JP6731782B2 - Release film for process that suppresses defective appearance of molded article, use thereof, and method for producing resin-sealed semiconductor using the release film - Google Patents

Description

The present invention relates to a release film for a process that can effectively suppress the appearance defect of a molded product, particularly an appearance defect due to wrinkles, preferably a release film for a semiconductor encapsulation process, and in particular, a semiconductor chip or the like is placed in a mold. The present invention relates to a process release film which is arranged between a semiconductor chip and the like and an inner surface of a mold when the resin is injection-molded, and a method of manufacturing a resin-sealed semiconductor using the release film.

In recent years, with the reduction in size and weight of semiconductor packages and the like, reduction of the amount of sealing resin used has been studied. It is desired to reduce the amount of release agent contained in the sealing resin so that the interface between the semiconductor chip and the resin can be firmly bonded even if the amount of the sealing resin used is reduced. .. For this reason, as a method of obtaining the mold releasability between the mold resin and the sealing resin after curing and molding, a method of disposing a release film between the inner surface of the mold and the semiconductor chip or the like is adopted.

As such a release film, a fluororesin film (for example, Patent Documents 1 and 2) and a poly-4-methyl-1-pentene resin film (for example, Patent Document 3) which are excellent in mold releasability and heat resistance are available. Proposed. However, these release films have a problem that wrinkles are likely to occur when they are attached to the inner surface of the mold, and the wrinkles are transferred to the surface of the molded product, resulting in poor appearance.

On the other hand, a laminated release film having a release layer and a heat resistant layer has been proposed. In these release films, the release layer has releasability, and the heat-resistant layer suppresses poor appearance. A typical one of these proposals focuses on the relationship of the storage elastic modulus between the release layer and the heat resistant layer (for example, refer to Patent Document 4). Patent Document 4 discloses a laminated release film in which the release layer has a relatively low storage elastic modulus and the heat-resistant layer has a relatively high storage elastic modulus, and more specifically, the release layer has a storage elastic modulus at 175°C. A release film for a semiconductor encapsulation process is described in which the modulus E′ is 45 MPa or more and 105 MPa or less, and the storage elastic modulus E′ of the heat-resistant layer at 175° C. is 100 MPa or more and 250 MPa or less.
Note that such a release film for process can be used not only in a semiconductor encapsulation process but also in a molding process of a reflector for a light emitting element such as a light emitting diode (see, for example, Patent Document 6).

In addition, the electrostatic charge of the release film also causes a defective appearance of the molded product. Since the release film used in the semiconductor encapsulation process is a resin film as described above, it is generally easily charged. For example, when the release film is unwound and used, static electricity is generated when the release film is peeled off, and foreign matter such as dust existing in the manufacturing atmosphere adheres to the charged release film and causes abnormal shape of the molded product (foreign matter). (Adhesion, etc.) and mold stains. In particular, some semiconductor chip sealing devices employ granular resin as the sealing resin, which causes shape abnormalities and mold stains due to the dust generated from the granular resin adhering to the release film, and the resulting contamination. The appearance defects described above cannot be ignored.
In recent years, in response to demands for thinner packages and improved heat dissipation, more and more packages have been formed in which semiconductor chips are flip-chip bonded and the back surface of the chips is exposed. This process is called a mold underfill (MUF) process. In the MUF process, sealing is performed in a state where the release film and the semiconductor chip are in direct contact with each other in order to protect and mask the semiconductor chip. At this time, if the release film is easily charged, there is a concern that the semiconductor chip may be broken due to charge-discharge during peeling.
Therefore, various techniques for preventing the charging of the sealing film have been proposed. For example, in Patent Document 5, a first thermoplastic resin layer in contact with a curable resin at the time of formation, a second thermoplastic resin layer in contact with a mold, a first thermoplastic resin layer, and a second thermoplastic resin layer. A release film comprising an intermediate layer disposed between a resin layer and the resin layer, the intermediate layer including a layer containing a polymeric antistatic agent.

JP, 2001-310336, A JP, 2002-110722, A JP-A-2002-361643 JP, 2010-208104, A International publication 2015/133630 A1 pamphlet JP, 2014-14928, A

However, with the development of the technical field, the required level for release films for processes such as release films for semiconductor encapsulation process is increasing year by year, and the process in which the appearance defect of the molded product is suppressed even under more severe process conditions. There is a strong demand for a release film for use, and in particular, a release film for a process in which the releasability, the suppression of appearance defects, and the mold followability are balanced at a particularly high level.

The present invention has been made in view of such circumstances, the molded product after resin sealing, can be easily released without using a mold structure or a release agent, and wrinkles or chips, abnormal shape ( It is an object of the present invention to provide a release film for a process, which can obtain a molded product without a defective appearance such as adhesion of foreign matter).

As a result of repeated intensive studies to solve the above problems, the present inventors have appropriately controlled the tensile elastic modulus at a specific temperature of the process release film, and a heat-resistant resin layer constituting the laminated film, It has been found that providing a layer containing a polymer-based charging agent is particularly important for suppressing appearance defects, and has completed the present invention.
That is, the present invention and each aspect thereof are as described in the following [1] to [23].

[1]
A release film for process, which is a laminated film including a release layer A and a heat-resistant resin layer B,
The release layer A has a contact angle with water of 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process, wherein the laminated film has a tensile elastic modulus at 120° C. of 75 MPa to 500 MPa.
[2]
The process release film according to [1], wherein the laminated film has a thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction of 3% or less.
[3]
The sum of the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction of the laminated film is 6% or less, [1 ] Or the release film for process as described in [2].
[4]
A release film for process, which is a laminated film including a release layer A and a heat-resistant resin layer B,
The release layer A has a contact angle with water of 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process as described above, wherein the laminated film has a tensile elastic modulus at 170° C. of 75 MPa to 500 MPa.
[5]
The release film for process according to [4], wherein the thermal dimensional change rate from 23° C. to 170° C. in the transverse (TD) direction of the laminated film is 4% or less.
[6]
The sum of the thermal dimensional change rate from 23°C to 170°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 170°C in the longitudinal (MD) direction of the laminated film is 7% or less. ] Or the release film for process according to [5].
[7]
The process according to any one of [1] to [6], wherein the heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent and an adhesive layer B2 containing an adhesive. Release film for.
[8]
The release film for process according to any one of [1] to [6], wherein the heat-resistant resin layer B comprises a layer B3 containing a polymer antistatic agent and an adhesive.
[9]
The release film for process according to any one of [1] to [8], wherein the heat dimensional change rate from 23° C. to 120° C. in the lateral (TD) direction of the heat-resistant resin layer B is 3% or less. ..
[10]
The sum of the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction of the heat resistant resin layer B is 6% or less. The release film for process according to [9].
[11]
The release film for process according to any one of [1] to [8], wherein the heat dimensional change rate of the heat-resistant resin layer B in the lateral (TD) direction from 23° C. to 170° C. is 3% or less. ..
[12]
The sum of the thermal dimensional change rate of 23° C. to 170° C. in the transverse (TD) direction and the thermal dimensional change rate of 23° C. to 120° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 5% or less. The release film for process according to [10].
[13]
The release layer A contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co)polymer, and a polystyrene resin, [1] to [12]. Release film for process described.
[14]
The release film for process according to any one of [1] to [13], wherein the heat-resistant resin layer B comprises a stretched film.
[15]
The release film for process according to [14], wherein the stretched film is selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film.
[16]
The heat of crystal fusion of 20 J/g or more and 100 J/g or less in the first temperature raising step measured by differential scanning calorimetry (DSC) according to JIS K7221 of the heat-resistant resin layer B, from [1] to [15] The release film for process according to any one of items.
[17]
The release film for process according to any one of [1] to [16], wherein the surface resistivity of the release layer A is 1×10 ¹³ Ω/□ or less.
[18]
The laminated film further has a release layer A′, and includes the release layer A, the heat-resistant resin layer B, and the release layer A′ in this order,
The release film for process according to any one of [1] to [17], wherein the release layer A′ has a contact angle with water of 90° to 130°.
[19]
At least one of the release layer A and the release layer A′ contains a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co)polymer, and a polystyrene resin, [18] The release film for process according to.
[20]
The release film for process according to [18] or [19], wherein the surface resistivity of the release layer A′ is 1×10 ¹³ Ω/□ or less.


[21]
The process release film [22] according to any one of [1] to [20], which is used in a sealing process using a thermosetting resin.
The process release film according to any one of [1] to [21], which is used in a semiconductor encapsulation process.
[23]
The release film for process according to any one of [1] to [21], which is used in a fiber-reinforced plastic molding process or a plastic lens molding process.
[24]
A method of manufacturing a resin-encapsulated semiconductor,
A step of disposing a resin-sealed semiconductor device at a predetermined position in a molding die,
A step of disposing the release film for semiconductor encapsulation process according to any one of [1] to [22] on the inner surface of the molding die so that the release layer A faces the semiconductor device; ,
After clamping the molding die, a step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process,
A method of manufacturing the above resin-encapsulated semiconductor, comprising:
[25]
A method of manufacturing a resin-sealed semiconductor,
A step of disposing a resin-sealed semiconductor device at a predetermined position in a molding die,
Arranging the release film for semiconductor encapsulation process according to any one of [18] to [20] on the inner surface of the molding die so that the release layer A′ faces the semiconductor device.
After clamping the molding die, a step of injecting and molding a sealing resin between the semiconductor device and the release film for semiconductor encapsulation process,
A method of manufacturing the above resin-encapsulated semiconductor, comprising:
In the present application, the “semiconductor device” is a concept including a semiconductor element (chip).

Since the release film for process of the present invention has a high level of releasability, suppression of defective appearance, and mold followability, which cannot be realized by the conventional technology, by using this, a semiconductor chip or the like is resin-sealed. It is possible to easily release the molded product obtained by stopping and the like, and it is possible to manufacture with high productivity a molded product that does not have a defective appearance such as wrinkles, chips, shape abnormalities (adhesion of foreign matter, etc.). The release film for process of the present invention is particularly suitable for use in a sealing device that employs a granular resin as a sealing resin.

It is a schematic diagram which shows an example of the release film for processes of this invention. It is a schematic diagram which shows the other example of the release film for processes of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin sealing semiconductor using the release film for processes of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin sealing semiconductor using the release film for processes of this invention. It is a schematic diagram which shows an example of the manufacturing method of the resin sealing semiconductor using the release film for processes of this invention. It is a schematic diagram which shows an example of the resin sealing semiconductor obtained by the manufacturing method of the resin sealing semiconductor of FIG. 4A and FIG. 4B.

Release film for process The release film for process of the present invention includes the following four aspects.
(First mode)
A release film for process, which is a laminated film including a release layer A and a heat-resistant resin layer B,
The release layer A has a contact angle with water of 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process, wherein the laminated film has a tensile elastic modulus at 120° C. of 75 MPa to 500 MPa.
(Second mode)
A release film for process, which is a laminated film including a release layer A and a heat-resistant resin layer B,
The release layer A has a contact angle with water of 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process as described above, wherein the laminated film has a tensile elastic modulus at 170° C. of 75 MPa to 500 MPa.
(Third aspect)
A release film for process, which is a laminated film including a release layer A, a heat-resistant resin layer B, and a release layer A′ in this order,
The contact angle of the release layer A and the release layer A′ with water is 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process, wherein the laminated film has a tensile elastic modulus at 120° C. of 75 MPa to 500 MPa.
(Fourth aspect)
A release film for process, which is a laminated film including a release layer A, a heat-resistant resin layer B, and a release layer A′ in this order,
The contact angle of the release layer A and the release layer A′ with water is 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
The release film for process as described above, wherein the laminated film has a tensile elastic modulus at 170° C. of 75 MPa to 500 MPa.

As is clear from the above aspects, the process release film of the present invention (hereinafter, also simply referred to as “release film”) is a release layer A having release properties for a molded article or a mold, and if desired, A laminated film comprising a release layer A′ and a heat-resistant resin layer B supporting the release layer, wherein the heat-resistant resin layer B contains a layer B1 containing a polymeric antistatic agent.

The process release film of the present invention is arranged on the inner surface of a molding die when a semiconductor element or the like is resin-sealed inside the molding die. At this time, the release layer A of the release film (which may be the release layer A′ when the release layer A′ is present) is placed on the resin-sealed side of the semiconductor element or the like (molded product). It is preferable to arrange them. By disposing the release film of the present invention, the resin-sealed semiconductor element or the like can be easily released from the mold.
The contact angle of the release layer A with water is 90° to 130°. By having such a contact angle, the release layer A has low wettability and is fixed to the cured sealing resin or the mold surface. The molded product can be easily released from the mold.
The contact angle of the release layer A with water is preferably 95° to 120°, more preferably 98° to 115°, and further preferably 100° to 110°.

As described above, since the release layer A (in some cases, the release layer A′) is disposed on the side of the molded product, from the viewpoint of the appearance of the molded product, the release layer A (in some cases, the release layer) in the resin sealing step is used. It is preferable to suppress the generation of wrinkles in the mold layer A′). This is because when wrinkles are generated in the release layer A (in some cases, the release layer A′), the generated wrinkles are transferred to the molded product, and the appearance of the molded product is likely to be poor.

In the present invention, in order to achieve the above object, as a laminated film constituting a release film for process, a release layer A (and optionally a release layer A′), and a heat-resistant resin supporting the release layer. A laminated film containing layer B, which has a tensile elastic modulus exhibiting a specific value, and which contains, as the heat-resistant resin layer B, a layer B1 containing a polymeric antistatic agent. Here, the laminated film containing the release layer A (and optionally the release layer A′) and the heat-resistant resin layer B supporting the release layer has a tensile elastic modulus at 120° C. of 75 MPa to 500 MPa. Or the tensile modulus at 170° C. is from 75 MPa to 500 MPa.
A mechanism in which a defective appearance of a molded article is extremely effectively suppressed by combining a laminated film having a tensile elastic modulus showing the above specific value and a heat-resistant resin layer including a layer containing a polymer antistatic agent. Is not necessarily clear, but the occurrence of wrinkles due to the tensile modulus of the laminated film being the above specific value, and the suppression of static electricity due to having a layer containing a polymeric antistatic agent and the process It is presumed that the suppression of the uptake of foreign matter such as the powder has some synergistic effect. That is, since foreign matter such as powder can be the starting point of wrinkles, suppressing the intake of foreign matter is more effective in suppressing the generation of wrinkles, while wrinkles can be the aggregation point of foreign matter. It is considered that the suppression of the occurrence of foreign matter is more effectively suppressed by the aggregation and growth of the foreign matter, and it has some relation with the suppression of the appearance defect of the molded product at a high level which could not be predicted by the conventional technology. Presumed.
Further, the surface resistivity of the release layer A (and optionally the release layer A′) of the laminated film is preferably 1×10 ¹³ Ω/□ or less from the viewpoint of preventing adhesion of dust and the like in the semiconductor manufacturing process, It is more preferably 5×10 ¹² Ω/□ or less, further preferably 1× ¹² Ω/□ or less, and particularly preferably 5×10 ¹¹ Ω/□ or less.
The surface resistivity of the release layer A (and optionally the release layer A′) of the laminated film can be measured, for example, by the method described in Examples of the present application.

As described above, the laminated film containing the release layer A (and optionally the release layer A′) and the heat-resistant resin layer B supporting the release layer has a tensile elastic modulus at 120° C. of from 75 MPa. It is 500 MPa or its tensile modulus at 170° C. is from 75 MPa to 500 MPa. Furthermore, the laminated film preferably has a tensile elastic modulus at 120° C. of 75 MPa to 500 MPa and a tensile elastic modulus at 170° C. of 75 MPa to 500 MPa.
When the tensile elastic modulus of the laminated film at 120° C. is 75 MPa to 500 MPa, or the tensile elastic modulus at 170° C. is 75 MPa to 500 MPa, wrinkles of the release layer in the resin sealing step or the like are generated. It can be effectively suppressed. The mechanism by which the occurrence of wrinkles in the release layer is suppressed by the tensile modulus of elasticity at a specific temperature of the laminated film constituting the release film for the process showing the above-mentioned specific value, but it is not always clear. It has a tensile elastic modulus of a certain value or more in the state of being restrained, so that deformation that leads to the generation of wrinkles is suppressed, and having a tensile elastic modulus of a certain value or less is related to the dispersion of strain. Presumed to be. If the pressure exceeds 500 MPa, the mold followability is poor, so that the end portion is less likely to be filled with the sealing resin, and there is a high possibility that appearance defects such as resin chipping occur.

The laminated film constituting the release film for process of the present invention preferably has a tensile elastic modulus at 120° C. of 80 MPa to 400 MPa,
More preferably from 85 MPa to 350 MPa,
More preferably from 88 MPa to 300 MPa,
Particularly preferably, it is 90 MPa to 280 MPa.
The laminated film constituting the release film for process of the present invention preferably has a tensile elastic modulus at 170° C. of 80 MPa to 400 MPa,
More preferably from 85 MPa to 350 MPa,
More preferably from 88 MPa to 300 MPa, more preferably from 90 MPa to 280 MPa, even more preferably from 95 MPa to 200 MPa,
It is particularly preferable that the pressure is 105 MPa to 170 MPa.
In the laminated film constituting the release film for process of the present invention, both the tensile elastic modulus at 120° C. and the tensile elastic modulus at 170° C. are both within the above-mentioned preferable range, and the flexibility in processing and It is particularly preferable because it has a wide range of applications.

Further, the laminated film containing the release layer A (and optionally the release layer A′) and the heat-resistant resin layer B supporting the release layer is from 23° C. to 120° C. in the TD direction (transverse direction). It is preferable that the thermal dimensional change rate is 3% or less, or the thermal dimensional change rate from 23° C. to 170° C. in the TD direction (transverse direction) is 4% or less. Further, the laminated film has a thermal dimensional change rate from 23° C. to 120° C. in the TD direction (transverse direction) of 3% or less and a thermal dimensional change from 23° C. to 170° C. in the TD direction (transverse direction). It is more preferable that the ratio is 4% or less.
The rate of thermal dimensional change from 23°C to 120°C in the TD direction (transverse direction) of the laminated film is 3% or less, or the thermal dimensional change from 23°C to 170°C in the TD direction (transverse direction). When the rate is 4% or less, it is possible to more effectively suppress the generation of wrinkles in the release layer in the resin sealing step and the like. In this embodiment, by using as the laminated film constituting the release film for process, the one in which the thermal dimensional change rate in the transverse (TD) direction exhibits the above-mentioned specific value, the generation of wrinkles in the release layer is further effectively suppressed. Although the mechanism is not clear, the use of a laminated film having a relatively small thermal expansion/contraction causes thermal expansion/contraction of the release layer A (or the release layer A′) due to heating/cooling during the process. It is speculated that it is related to being suppressed.

The laminated film constituting the release film for process of the present embodiment preferably has a thermal dimensional change rate from 23° C. to 120° C. in the TD direction (transverse direction) of 2.5% or less and 2.0. % Or less is more preferable, and 1.5% or less is further preferable. On the other hand, the laminated film preferably has a thermal dimensional change rate of −5.0% or more from 23° C. to 120° C. in the TD direction (transverse direction).
The laminated film constituting the release film for process of the present embodiment preferably has a thermal dimensional change rate of 3.5% or less from 23° C. to 170° C. in the TD direction (transverse direction), and is 3.0% or less. % Or less is more preferable, and 2.0% or less is still more preferable. On the other hand, the laminated film preferably has a thermal dimensional change rate of −5.0% or more from 23° C. to 170° C. in the TD direction (transverse direction).

The process release film of the present invention, which is a laminated film including the release layer A (and optionally the release layer A′) and the heat-resistant resin layer B supporting the release layer, has a TD direction (transverse direction). ) And the thermal dimensional change rate in the MD direction (longitudinal direction during the production of the film; hereinafter also referred to as “longitudinal (MD) direction”) are preferably equal to or less than a specific value.
That is, the sum of the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction of the laminated film is 6% or less. On the other hand, the laminated film is preferably the sum of the thermal dimensional change rate from 23° C. to 120° C. in the TD direction (transverse direction) and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction. Is preferably -5.0% or more.
The thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the longitudinal (MD) direction of the laminated film containing the release layer A (and optionally the release layer A′) and the heat-resistant resin layer B. When the sum of the thermal dimensional change rates from 23° C. to 120° C. is 6% or less, the generation of wrinkles when mounted on the inner surface of the mold can be more effectively suppressed.

Further, the thermal dimensional change rate from 23° C. to 170° C. and the longitudinal direction (MD) in the transverse (TD) direction of the laminated film containing the release layer A (and the release layer A′ if desired) and the heat-resistant resin layer B. The sum of the thermal dimensional change rates from 23°C to 170°C in the direction is preferably 7% or less, while the laminated film has a thermal dimension from 23°C to 170°C in the TD direction (transverse direction). The sum of the rate of change and the rate of thermal dimensional change from 23° C. to 170° C. in the longitudinal (MD) direction is preferably −5.0% or more.
Since the sum of the thermal dimensional change rate from 23° C. to 170° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 170° C. in the longitudinal (MD) direction of the laminated film is 7% or less, It is possible to more effectively suppress the generation of wrinkles when mounted on the inner surface of the mold.

Release layer A
The release layer A constituting the release film for process of the present invention has a contact angle to water of 90° to 130°, preferably 95° to 120°, more preferably 98° to 115°, More preferably, it is 100° to 110°. It is preferable to include a resin selected from the group consisting of a fluororesin, a 4-methyl-1-pentene (co)polymer, and a polystyrene-based resin, from the viewpoint of excellent mold releasability of a molded product and easy availability.

The fluororesin that can be used for the release layer A may be a resin containing a structural unit derived from tetrafluoroethylene. Although it may be a homopolymer of tetrafluoroethylene, it may be a copolymer with other olefins. Examples of other olefins include ethylene. A copolymer containing tetrafluoroethylene and ethylene as a monomer constitutional unit is a preferred example, and in such a copolymer, the proportion of constitutional units derived from tetrafluoroethylene is 55 to 100% by mass, and ethylene It is preferable that the ratio of the structural units derived from is 0 to 45% by mass.

The 4-methyl-1-pentene (co)polymer that can be used for the release layer A may be a homopolymer of 4-methyl-1-pentene, or 4-methyl-1-pentene, It may be a copolymer with another olefin having 2 to 20 carbon atoms (hereinafter referred to as "olefin having 2 to 20 carbon atoms").

In the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the olefin having 2 to 20 carbon atoms copolymerized with 4-methyl-1-pentene is 4-methyl. -1- It can give flexibility to the pentene. Examples of the olefin having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1 -Octadecene, 1-eicosene and the like are included. These olefins may be used alone or in combination of two or more.

In the case of a copolymer of 4-methyl-1-pentene and an olefin having 2 to 20 carbon atoms, the proportion of constituent units derived from 4-methyl-1-pentene is 96 to 99% by mass, and other than that. It is preferable that the ratio of the constituent unit derived from the olefin having 2 to 20 carbon atoms is 1 to 4% by mass. By reducing the content of the olefin-derived structural unit having 2 to 20 carbon atoms, the copolymer can be hardened, that is, the storage elastic modulus E'can be increased, and the occurrence of wrinkles in the sealing step or the like can be suppressed. Is advantageous to. On the other hand, by increasing the content of the structural unit derived from the olefin having 2 to 20 carbon atoms, the copolymer can be softened, that is, the storage elastic modulus E'can be lowered, and the mold followability can be improved. Is advantageous to.

The 4-methyl-1-pentene (co)polymer can be produced by methods known to those skilled in the art. For example, it can be produced by a method using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. The 4-methyl-1-pentene (co)polymer is preferably a (co)polymer having high crystallinity. The crystalline copolymer may be either a copolymer having an isotactic structure or a syndiotactic structure, but is particularly a copolymer having an isotactic structure. Is preferable from the viewpoint of physical properties and is easily available. Furthermore, the 4-methyl-1-pentene (co)polymer can be molded into a film, and if it has a strength to withstand the temperature and pressure at the time of mold molding, the stereoregularity and the molecular weight are also particularly limited. Not done. The 4-methyl-1-pentene copolymer may be a commercially available copolymer such as TPX (registered trademark) manufactured by Mitsui Chemicals, Inc.

The polystyrene resin that can be used for the release layer A includes a homopolymer and a copolymer of styrene, and the structural unit derived from styrene contained in the polymer is at least 60% by weight or more. It is preferably 80% by weight or more.
The polystyrene-based resin may be isotactic polystyrene or syndiotactic polystyrene, but isotactic polystyrene is preferable from the viewpoint of transparency, availability, etc., and releasability, heat resistance, etc. From the viewpoint of, syndiotactic polystyrene is preferable. Polystyrene may be used alone or in combination of two or more.

The release layer A preferably has heat resistance capable of withstanding the mold temperature during molding (typically 120 to 180° C.). From this viewpoint, the release layer A preferably contains a crystalline resin having a crystalline component, and the melting point of the crystalline resin is preferably 190°C or higher, more preferably 200°C or higher and 300°C or lower.
In order to provide the release layer A with crystallinity, for example, the fluororesin preferably contains at least a structural unit derived from tetrafluoroethylene, and the 4-methyl-1-pentene (co)polymer has 4-methyl-1. -It is preferable to include at least a constitutional unit derived from pentene, and it is preferable that the polystyrene-based resin include at least syndiotactic polystyrene. Since the resin constituting the release layer A contains a crystal component, wrinkles are less likely to occur in the resin sealing step and the like, and it is preferable to prevent the wrinkles from being transferred to the molded product and causing a poor appearance. ..

The resin containing the crystalline component that constitutes the release layer A has a heat of crystal fusion of 15 J/g or more and 60 J/g or less in the first heating step measured by differential scanning calorimetry (DSC) according to JIS K7221. Is preferable, and more preferably 20 J/g or more and 50 J/g or less. When it is 15 J/g or more, heat resistance and mold releasability capable of withstanding hot press molding in a resin sealing step and the like can be more effectively exhibited, and also the dimensional change rate is suppressed. As a result, wrinkles can be prevented from occurring. On the other hand, when the amount of heat of crystal fusion is 60 J/g or less, the release layer A has an appropriate hardness, and therefore, sufficient followability of the film to the mold can be obtained in the resin sealing step and the like. There is no risk of film damage.

The release layer A may further contain another resin in addition to the fluororesin, the 4-methyl-1-pentene copolymer, and/or the polystyrene resin. In this case, it is preferable that the hardness of the other resin is relatively high. Examples of other resins include polyamide-6, polyamide-66, polybutylene terephthalate, polyethylene terephthalate. Thus, even when the release layer A contains a large amount of soft resin (for example, a large amount of olefin having 2 to 20 carbon atoms in the 4-methyl-1-pentene copolymer), the hardness is relatively high. By further containing a high resin, the release layer A can be hardened, which is advantageous in suppressing the generation of wrinkles in the sealing step and the like.

The content of these other resins is preferably, for example, 3 to 30 mass% with respect to the resin component forming the release layer A. When the content of the other resin is 3 mass or more, the effect of the addition can be substantial, and when the content of the other resin is 30 mass% or less, the releasability of the mold or the molded product is maintained. be able to.

In addition, the release layer A includes, in addition to the fluororesin, 4-methyl-1-pentene (co)polymer, and/or polystyrene-based resin, a heat-resistant stabilizer and a weather-resistant stabilizer as long as the object of the present invention is not impaired. , A rust preventive agent, a copper anti-corrosion stabilizer, an antistatic agent, and the like, which may be included in known additives that are generally blended with the resin for film. The content of these additives can be, for example, 0.0001 to 10 parts by weight with respect to 100 parts by weight of the fluororesin, 4-methyl-1-pentene copolymer, and/or polystyrene resin.

The thickness of the release layer A is not particularly limited as long as it has sufficient releasability for a molded product, but is usually 1 to 50 μm, preferably 5 to 30 μm.

The surface of the release layer A may have a concavo-convex shape if necessary, and thereby the releasability can be improved. The method of providing the surface of the release layer A with unevenness is not particularly limited, but a general method such as embossing can be adopted.

Release layer A'
The release film for process of the present invention may further include a release layer A′ in addition to the release layer A and the heat-resistant resin layer B. That is, the process release film of the present invention may be a process release film that is a laminated film including the release layer A, the heat-resistant resin layer B, and the release layer A′ in this order.
The contact angle of water of the release layer A′, which may constitute the release film for process of the present invention, is 90° to 130°, preferably 95° to 120°, and more preferably 98°. 115°, more preferably 100° to 110°. Then, the preferable material, configuration, physical properties and the like of the release layer A′ are the same as those described for the release layer A above.

When the process release film is a laminated film including a release layer A, a heat-resistant resin layer B, and a release layer A′ in this order, the release layer A and the release layer A′ are the same. It may be a layer having a different structure or a layer having a different structure.
From the viewpoint of prevention of warpage and ease of handling due to the fact that both surfaces have similar releasability, the release layer A and the release layer A′ may have the same or substantially the same configuration. It is preferable that the mold release layer A and the mold release layer A′ are designed optimally in relation to the process using the mold release layer A, for example, the mold release layer A should be excellent in mold releasability from the mold. From the viewpoint of making the layer A′ excellent in releasability from the molded product, it is preferable that the release layer A and the release layer A′ have different configurations.
When the release layer A and the release layer A′ have different configurations, the release layer A and the release layer A′ may be made of the same material and have different configurations such as thickness. However, the material and the other structure may be different.

Heat resistant resin layer B
The heat-resistant resin layer B constituting the release film for process of the present invention has a function of supporting the release layer A (and the release layer A′ in some cases) and suppressing the generation of wrinkles due to mold temperature and the like.
The heat-resistant resin layer B constituting the release film for process of the present invention includes a layer B1 containing a polymer antistatic agent. Here, "including" the layer B1 containing a polymeric antistatic agent means that the heat resistant resin layer B is entirely composed of the layer B1 containing a polymeric antistatic agent, and When a part of B is composed of the layer B1 containing a polymeric antistatic agent, it is used to the effect of including both. Therefore, the heat-resistant resin layer B may or may not further include a layer other than the layer B1 containing the polymer antistatic agent.

The heat-resistant resin layer B constituting the release film for process of the present invention has a low surface specific resistance value by including the layer B1 containing a polymer antistatic agent, and contributes to antistatic property.
Surface resistivity of the heat-resistant resin layer B, from the viewpoint of preventing adhesion of dust or the like into the release layer A of the laminated film of the present invention, preferably ¹⁰ 10 Ω / □ or less, particularly preferably 10 ⁹ Ω / □ or less .. When the surface resistivity is 10 ¹⁰ Ω/□ or less, the antistatic property is effectively exhibited even on the surface of the release film for process of the present invention. Therefore, it is possible to effectively suppress the adhesion of foreign matter such as dust due to static electricity, and, for example, even when a part of the semiconductor element is in direct contact with the process release film during the manufacture of the semiconductor package, the process release film It is possible to effectively suppress the destruction of the semiconductor element due to charging-discharging.
The surface resistivity of the heat-resistant resin layer B is preferably as low as possible from the viewpoint of preventing adhesion of dust and the like to the release layer A of the laminated film of the present invention, and the lower limit is not particularly limited. The surface resistivity of the heat-resistant resin layer B tends to decrease as the conductivity of the polymer antistatic agent increases and the content of the polymer antistatic agent increases.
The surface specific resistance value of the heat-resistant resin layer B can be measured, for example, by the method described in Examples of the present application. However, the heat resistant resin layer B before lamination is used as a sample.

As the layer other than the layer B1 containing the polymer antistatic agent, for example, an adhesive layer B2 containing an adhesive can be preferably used. That is, the heat resistant resin layer B may include a layer B1 containing a polymer antistatic agent and an adhesive layer B2 containing an adhesive.
In this case, the heat-resistant resin layer B may be composed of only the layer B1 containing the polymer antistatic agent and the adhesive layer B2 containing the adhesive, or the layer containing the polymer antistatic agent. B1 and a layer other than the adhesive layer B2 containing an adhesive, for example, a layer of a thermoplastic resin containing no antistatic agent or an adhesive, a gas barrier layer, or the like may be further included.

The layer B1 containing the polymer antistatic agent may also contain an adhesive. That is, the heat resistant resin layer B may include the layer B3 containing a polymer antistatic agent and an adhesive.
In this case, the heat-resistant resin layer B may be composed of only the layer B3 containing the polymer antistatic agent and the adhesive, or other than the layer B3 containing the polymer antistatic agent and the adhesive. Other layers, for example, a layer B1 containing a polymer antistatic agent, an adhesive layer B2 containing an adhesive, a layer of a thermoplastic resin containing no antistatic agent or an adhesive, a gas barrier layer and the like may be further included. ..

In the release film for process of the present invention, the thermal dimensional change rate from 23° C. to 120° C. in the lateral (TD) direction of the heat resistant resin layer B is 3% or less, or the lateral (TD) of the heat resistant resin layer B (TD). It is preferable that the thermal dimensional change rate from 23° C. to 170° C. in the () direction is 3% or less. Furthermore, the heat-resistant resin layer B has a thermal dimension change rate of 23% to 120° C. in the lateral (TD) direction of 3% or less, and a thermal dimension of 23° C. to 170° C. in the lateral (TD) direction. It is more preferable that the rate of change is 3% or less.
The heat dimensional change rate from 23° C. to 120° C. in the lateral (TD) direction of the heat resistant resin layer B is 3% or less, or the heat from 23° C. to 170° C. in the lateral (TD) direction of the heat resistant resin layer B. When the dimensional change rate is 3% or less, it is possible to more effectively suppress the generation of wrinkles when the wrinkle is mounted on the inner surface of the mold.
As the heat-resistant resin layer B, by using a resin layer whose thermal dimensional change rate in the lateral (TD) direction exhibits the above-mentioned specific value, the mechanism by which the generation of wrinkles in the release layer is more effectively suppressed is not always clear. However, by using the heat-resistant resin layer B having relatively small thermal expansion/contraction, thermal expansion/contraction of the release layer A (or the release layer A′) due to heating/cooling during the process is suppressed. It is presumed to be related to.

As the heat-resistant resin layer B, any resin layer can be used including a non-stretched film, but it is particularly preferable to include a stretched film.
The stretched film tends to have a low or negative thermal expansion coefficient due to the influence of stretching in the manufacturing process, and the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction is 3% or less. Alternatively, since it is relatively easy to realize the characteristic that the thermal dimensional change rate from 23° C. to 170° C. in the lateral (TD) direction of the heat resistant resin layer B is 3% or less, It can be used preferably.
The thermal dimensional change rate of the heat-resistant resin layer B in the transverse (TD) direction from 23° C. to 120° C. is preferably 2% or less, more preferably 1.5% or less, and more preferably 1% or less. More preferably, on the other hand, it is preferably -10% or more.
The thermal dimensional change rate of the heat-resistant resin layer B in the lateral (TD) direction from 23° C. to 170° C. is preferably 2% or less, more preferably 1.5% or less, and more preferably 1% or less. More preferably, on the other hand, it is preferably -10% or more.

In the release film for process of the present invention, the thermal dimensional change rate of the heat-resistant resin layer B in the transverse (TD) direction from 23° C. to 120° C. and the thermal dimensional change in the longitudinal (MD) direction from 23° C. to 120° C. The sum of the rates is 6% or less, or the thermal dimension change rate of the heat-resistant resin layer B from 23°C to 170°C in the lateral (TD) direction and the thermal dimension from 23°C to 170°C in the longitudinal (MD) direction. The sum of change rates is preferably 5% or less. The sum of the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 6% or less, and The sum of the thermal dimensional change rate from 23° C. to 170° C. in the transverse (TD) direction of the heat-resistant resin layer B and the thermal dimensional change rate from 23° C. to 170° C. in the longitudinal (MD) direction is 5% or less. Is more preferable. Since the sum of the thermal dimensional change rate in the lateral (TD) direction and the thermal dimensional change rate in the longitudinal (MD) direction of the heat-resistant resin layer B is within the above range, the occurrence of wrinkles when mounted on the inner surface of the mold is further increased. It can be effectively suppressed.
The sum of the thermal dimensional change rate from 23°C to 120°C in the transverse (TD) direction of the heat-resistant resin layer B and the thermal dimensional change rate from 23°C to 120°C in the longitudinal (MD) direction is -3.0% or more. It is more preferably 5.0% or less, and further preferably -2.0% or more and 4.5% or less.
The sum of the thermal dimensional change rate from 23° C. to 170° C. in the lateral (TD) direction of the heat-resistant resin layer B and the thermal dimensional change rate from 23° C. to 170° C. in the longitudinal (MD) direction is −15.5% or more. It is more preferably 5.0% or less, further preferably -10.0% or more and 4.5% or less.
It is advantageous to use a stretched film from the viewpoint that the sum of the rate of thermal dimensional change in the transverse (TD) direction and the rate of thermal dimensional change in the longitudinal (MD) direction of the heat-resistant resin layer B is within the above range. It is particularly advantageous to properly control the conditions.

The stretched film may be a uniaxially stretched film or a biaxially stretched film. When the film is a uniaxially stretched film, it may be either longitudinally stretched or horizontally stretched, but it is preferably stretched in at least the transverse (TD) direction.
The method and apparatus for obtaining the stretched film are not particularly limited, and stretching may be performed by a method known in the art. For example, it can be stretched with a heating roll or a tenter type stretching machine.

As the stretched film, it is preferable to use a stretched film selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film. These stretched films are relatively easy to reduce the thermal expansion coefficient in the transverse (TD) direction or to make them negative by stretching, and have mechanical properties suitable for the use of the present invention, and It is particularly suitable as a stretched film in the heat resistant resin layer B because it is inexpensive and relatively easy to obtain.

As the stretched polyester film, a stretched polyethylene terephthalate (PET) film and a stretched polybutylene terephthalate (PBT) film are preferable, and a biaxially stretched polyethylene terephthalate (PET) film is particularly preferable.
The polyamide constituting the stretched polyamide film is not particularly limited, but polyamide-6, polyamide-66 and the like can be preferably used.
As the stretched polypropylene film, a uniaxially stretched polypropylene film, a biaxially stretched polypropylene film or the like can be preferably used.
The stretching ratio is not particularly limited, the thermal dimensional change rate is appropriately controlled, and an appropriate value may be appropriately set in order to realize suitable mechanical properties. , The transverse direction is preferably 2.7 to 8.0 times, and in the case of a stretched polyamide film, the longitudinal direction and the transverse direction are preferably 2.7 to 5.0 times, and stretched. In the case of a polypropylene film, in the case of a biaxially stretched polypropylene film, it is preferable that both the longitudinal direction and the transverse direction are in the range of 5.0 to 10.0 times, and in the case of a uniaxially stretched polypropylene film, 1. It is preferably in the range of 5 to 10.0 times.

The heat-resistant resin layer B has heat resistance that can withstand the temperature of the mold (typically 120 to 180° C.) during molding from the viewpoint of controlling the strength of the film and the rate of thermal dimensional change within an appropriate range. It is preferable. From this viewpoint, the heat-resistant resin layer B preferably contains a crystalline resin having a crystalline component, the melting point of the crystalline resin is preferably 125° C. or higher, and the melting point is 155° C. or higher and 300° C. or lower. Is more preferable, 185 to 210° C. is further preferable, and 185 to 205° C. is particularly preferable.

As described above, the heat resistant resin layer B preferably contains a crystalline resin having a crystalline component. As the crystalline resin to be contained in the heat resistant resin layer B, a crystalline resin such as a polyester resin, a polyamide resin or a polypropylene resin can be used in part or in whole. Specifically, it is preferable to use polyethylene terephthalate or polybutylene terephthalate for the polyester resin, polyamide 6 or polyamide 66 for the polyamide resin, and isotactic polypropylene for the polypropylene resin.

By including the crystalline component of the crystalline resin in the heat-resistant resin layer B, wrinkles are less likely to occur in the resin sealing step or the like, and it is more advantageous to prevent the wrinkles from being transferred to the molded product and causing a poor appearance. Become.
The resin constituting the heat-resistant resin layer B preferably has a heat of crystal fusion of 20 J/g or more and 100 J/g or less in the first heating step measured by differential scanning calorimetry (DSC) according to JIS K7221. It is more preferably 25 J/g or more and 65 J/g or less, more preferably 25 J/g or more and 55 J/g or less, more preferably 28 J/g or more and 50 J/g or less, and 28 J/g. It is more preferably g or more and 40 J/g or less, further preferably 28 J/g or more and 35 J/g or less. When it is 20 J/g or more, heat resistance and releasability capable of withstanding hot press molding in a resin sealing step or the like can be effectively exhibited, and the dimensional change rate can be suppressed to a small extent. It is also possible to prevent wrinkles from occurring. On the other hand, when the heat of crystal fusion is 100 J/g or less, appropriate hardness can be imparted to the heat-resistant resin layer B, so that the film can sufficiently follow the mold in the resin sealing step and the like. In addition to this, there is no possibility that the film is easily damaged. In the present embodiment, the heat of fusion of crystals means the heat quantity (J/g) on the vertical axis and the heat quantity (J/g) on the horizontal axis obtained in the first heating step in the measurement by differential scanning calorimetry (DSC) according to JIS K7221. In the chart showing the relationship with the temperature (°C), it means the numerical value obtained by the sum of the peak areas having a peak at 120°C or higher.
The heat of crystal fusion of the heat-resistant resin layer B can be adjusted by appropriately setting the heating and cooling conditions during film production and the stretching conditions.

The thickness of the heat resistant resin layer B is not particularly limited as long as the film strength can be secured, but is usually 1 to 1
The thickness is 00 μm, preferably 5 to 50 μm.

Layer B1 containing a polymeric antistatic agent
It is known that the polymer antistatic agent in the layer B1 containing the polymer antistatic agent, which is preferably used in the heat resistant resin layer B constituting the laminate of the present invention, has an antistatic function. A polymer compound can be used. For example, a cationic copolymer having a quaternary ammonium salt group as a side group, an anionic compound containing polystyrene sulfonic acid, a compound having a polyalkylene oxide chain (preferably a polyethylene oxide chain or a polypropylene oxide chain), a polyethylene glycol methacrylate copolymer. Examples thereof include polymers, polyether ester amides, polyether amide imides, polyether esters, nonionic polymers such as ethylene oxide-epichlorohydrin copolymers, and π-conjugated conductive polymers. These may be used alone or in combination of two or more.

The quaternary ammonium base in the copolymer having a quaternary ammonium base as a side group has an effect of imparting a rapid dielectric polarization relaxation property due to dielectric polarizability and conductivity.
The copolymer preferably has a carboxy group as a side group together with a quaternary ammonium salt group. When the copolymer has a carboxy group, the copolymer has crosslinkability and can form the layer B1 by itself. In addition, when used in combination with an adhesive such as a urethane-based adhesive, it can react with the adhesive to form a crosslinked structure and significantly improve adhesiveness, durability and other mechanical properties.
The copolymer may further have a hydroxy group as a side group. The hydroxy group has the effect of reacting with a functional group in the adhesive, such as an isocyanate group, to enhance the adhesiveness.

The copolymer can be obtained by copolymerizing the above-mentioned monomers having each functional group. Specific examples of the monomer having a quaternary ammonium salt group include dimethylaminoethyl acrylate quaternary compounds (including anions such as chloride, sulfate, sulfonate, and alkylsulfonate as counterions). Specific examples of the monomer having a carboxy group include (meth)acrylic acid, (meth)acroyloxyethylsuccinic acid, phthalic acid, and hexahydrophthalic acid.
It is also possible to copolymerize monomers other than these. Examples of the other monomer include alkyl (meth)acrylates, styrene, vinyl acetate, vinyl halides, vinyl derivatives such as olefins, and the like.

The proportion of copolymerized units having each functional group in the copolymer can be set appropriately. The proportion of copolymerized units having a quaternary ammonium salt group is preferably 15 to 40 mol% with respect to the total of all copolymerized units. When this ratio is 15 mol% or more, the antistatic effect is excellent. If it exceeds 40 mol %, the hydrophilicity of the copolymer may be too high. The proportion of units having a carboxy group is preferably 3 to 13 mol% based on the total of all units.

When the copolymer has a carboxy group as a side group, a crosslinking agent (curing agent) may be added to the copolymer. Examples of the crosslinking agent include bifunctional epoxy compounds such as glycerin diglycidyl ether, trifunctional epoxy compounds such as trimethylolpropane triglycidyl ether, and polyfunctional compounds such as ethyleneimine compounds such as trimethylolpropane triaziridinyl ether.
An imidazole derivative such as 2-methylimidazole, 2-ethyl, 4-methylimidazole or the like and other amines may be added to the copolymer as a ring-opening reaction catalyst of the bifunctional or trifunctional epoxy compound.

The π-conjugated conductive polymer is a conductive polymer having a main chain with developed π-conjugation. As the π-conjugated conductive polymer, known compounds can be used, and examples thereof include polythiophene, polypyrrole, polyaniline, and their derivatives.

As the polymer antistatic agent, those produced by a known method may be used, or commercially available products may be used. For example, as a commercial product of a copolymer having a quaternary ammonium salt group and a carboxy group as a side group, "BONDEIP (trade name)-PA100 main agent" manufactured by Konishi Co., Ltd. may be mentioned.

The following layers (1) to (4) and the like can be mentioned as preferred embodiments of the layer B1 containing a polymer antistatic agent.
Layer (1): The polymeric antistatic agent itself has a film-forming ability, and the polymeric antistatic agent is formed as it is or after being dissolved in a solvent and wet-coated, and dried if necessary. Layers.
Layer (2): a layer in which the polymeric antistatic agent itself has a film-forming ability and is meltable, and is formed by melt-coating the polymeric antistatic agent.
Layer (3): The binder has a film-forming ability and is meltable, and is formed by melt-coating a composition in which a polymeric antistatic agent is dispersed or dissolved in the binder. Layers.
Layer (4): The binder has a film-forming ability, and the composition containing the binder and the polymeric antistatic agent is applied as it is or in a solvent and wet-coated, and dried if necessary. Layer formed by. However, what corresponds to layer (1) does not correspond to layer (4).

In the layer (1), the polymeric antistatic agent itself has a film-forming ability means that the polymeric antistatic agent is soluble in a solvent such as an organic solvent and the solution is wet-coated and dried. Means that a film is formed on.
In the layer (2), the fact that the polymeric antistatic agent itself can be melted means that it can be melted by heating. “Having film forming ability” and “meltable” with respect to the binder in layers (3) and (4) have the same meaning.

The polymer antistatic agent in the layer (1) may or may not have crosslinkability. When the polymer antistatic agent has a crosslinking property, a crosslinking agent may be used together.
Examples of the polymer type antistatic agent having film forming ability and crosslinkability include a copolymer having a quaternary ammonium salt group and a carboxy group as the side groups.
Examples of the cross-linking agent include those mentioned above.
The thickness of the layer (1) is preferably 0.01 to 1.0 μm, particularly preferably 0.03 to 0.5 μm. When the thickness of the layer (1) is 0.01 μm or more, it is possible to easily obtain a sufficient antistatic effect, and when it is 1.0 μm or less, sufficient adhesion can be obtained during lamination. It will be easier.
Examples of the polymeric antistatic agent in the layer (2) include a polyolefin resin containing a surfactant, carbon black and the like. Examples of commercially available products include Perectron HS (manufactured by Sanyo Kasei Co., Ltd.). The preferable range of the thickness of the layer (2) is the same as the preferable range of the thickness of the layer (1).

Examples of the binder in the layer (3) include general-purpose thermoplastic resins. The thermoplastic resin is preferably a resin having a functional group that contributes to adhesion so that it will adhere during melt molding. A carbonyl group etc. are mentioned as this functional group.
The content of the polymeric antistatic agent in the layer (3) is preferably 10 to 40 parts by mass, and particularly preferably 10 to 30 parts by mass based on the total mass of the layer (3). The preferable range of the thickness of the layer (3) is the same as the preferable range of the thickness of the layer (1).

One example of a composition forming layer (4) is an adhesive. The adhesive means an adhesive containing a main agent and a curing agent, which exhibits adhesiveness when cured by heating or the like.
At this time, the layer B1 containing the polymeric antistatic agent also corresponds to the layer B3 containing the polymeric antistatic agent and the adhesive.
The adhesive may be a one-component adhesive or a two-component adhesive.
As the adhesive forming the layer (4) (hereinafter, also referred to as the adhesive for forming the layer (4)), for example, a polymer antistatic agent is added to an adhesive containing no polymer antistatic agent. The thing etc. are mentioned.
The polymer type antistatic agent added to the adhesive may have a film forming ability or may not have a film forming ability (for example, π-conjugated conductive polymer).
As the adhesive containing no polymer antistatic agent, known adhesives for dry lamination can be used. For example, polyvinyl acetate adhesives; homopolymers or copolymers of acrylic acid esters (ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), or acrylic acid esters and other monomers (methacrylic acid). Methyl, acrylonitrile, styrene, etc.) polyacrylic ester adhesives such as copolymers; cyanoacrylate adhesives; ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid) Etc.) ethylene copolymer-based adhesive consisting of a copolymer or the like; cellulose-based adhesive; polyester-based adhesive; polyamide-based adhesive; polyimide-based adhesive; urea resin or melamine resin-based amino resin-based adhesive Adhesives; phenolic resin adhesives; epoxy adhesives; polyurethane adhesives that crosslink polyols (polyether polyols, polyester polyols, etc.) with isocyanates and/or isocyanurates; reactive (meth)acrylic adhesives Rubber adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc.; Silicone adhesives; Inorganic adhesives made of alkali metal silicate, low melting point glass, etc.; Other adhesives can be used.

The content of the polymeric antistatic agent in the adhesive for forming the layer (4) is preferably such that the surface resistivity of the layer (4) is 10 ¹⁰ Ω/□ or less, and 10 ⁹ Ω/□ or less. Particularly preferred.
From the viewpoint of antistatic, the higher the content of the polymer antistatic agent in the adhesive for forming the layer (4) is, the more preferable. However, the polymer antistatic agent is a π-conjugated conductive polymer, When the layer B1 is formed by using an adhesive containing no π-conjugated conductive polymer as an adhesive containing no molecular antistatic agent to form the layer B1, the content of the polymeric antistatic agent When the amount is large, the adhesiveness of the layer (4) is deteriorated, and the adhesiveness between the first thermoplastic resin layer 2 and the second thermoplastic resin layer 3 may be insufficient. Therefore, the content of the polymer antistatic agent in the adhesive for forming the layer (4) in this case is preferably 40% by mass or less, and 30% by mass or less, based on the solid content of the resin serving as the binder. Is particularly preferable. The lower limit is preferably 1% by mass, and particularly preferably 5% by mass.

The thickness of the layer (4) is preferably 0.2 to 5 μm, particularly preferably 0.5 to 2 μm. When the thickness of the layer (4) is at least the lower limit value of the above range, the adhesiveness between the first thermoplastic resin layer and the second thermoplastic resin layer will be excellent, and the antistatic property will be excellent. When it is at most the upper limit of the above range, the productivity will be excellent.

The polymer antistatic layer included in the layer B1 may be one layer or two or more layers. For example, it may have only one kind of layers (1) to (4), or may have two or more kinds.
As the polymer antistatic layer, the layer (1) is preferable from the viewpoint of easy production. The layer (1) and any one or more of the layers (2) to (4) may be used in combination.

Adhesive layer B2
As the adhesive contained in the adhesive layer B2, which is preferably used in the heat resistant resin layer B constituting the laminate of the present invention, a conventionally known adhesive can be appropriately used. From the viewpoint of a political party for manufacturing the laminate of the present invention, an adhesive for dry lamination can be preferably used. For example, polyvinyl acetate adhesives; homopolymers or copolymers of acrylic acid esters (ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc.), or acrylic acid esters and other monomers (methacrylic acid). Polyacrylic ester adhesives composed of copolymers with methyl acid, acrylonitrile, styrene, etc.; cyanoacrylate adhesives; ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacryl) Ethylene copolymer adhesives consisting of copolymers with acids, etc.; Cellulose adhesives; Polyester adhesives; Polyamide adhesives; Polyimide adhesives; Urea resins or melamine resins, etc. amino resins -Based adhesives; phenolic resin-based adhesives; epoxy-based adhesives; polyurethane-based adhesives that crosslink polyols (polyether polyols, polyester polyols, etc.) with isocyanates and/or isocyanurates; reactive (meth)acrylic adhesives Agents; rubber adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc.; silicone adhesives; inorganic adhesives made of alkali metal silicate, low melting point glass, etc. You can

Layer B3 containing a polymeric antistatic agent and an adhesive
The polymer antistatic agent contained in the layer B3 containing the polymer antistatic agent and the adhesive, which is preferably used in the heat-resistant resin layer B constituting the laminate of the present invention, includes polymer antistatic agents Polymeric antistatic agents similar to those described above for the layer B1 containing an agent can be preferably used, and as the adhesive, the same adhesive as described above for the adhesive layer B2 containing an adhesive is suitable. Can be used for.
In the above-mentioned layer (4), when the composition forming the layer (4) is an adhesive, it is a particularly preferable example as an aspect of the layer B3 containing a polymer antistatic agent and an adhesive.

Other Layers The release film for process of the present invention may have layers other than the release layer A, the heat-resistant resin layer B, and the release layer A′ as long as the object of the present invention is not impaired. For example, an adhesive layer may be provided between the release layer A (or the release layer A′) and the heat resistant resin layer B, if necessary. The material used for the adhesive layer is not particularly limited as long as it can firmly bond the release layer A and the heat-resistant resin layer B and does not separate even in the resin sealing step and the release step.

For example, when the release layer A (or the release layer A′) contains a 4-methyl-1-pentene copolymer, the adhesive layer is a modified 4-methyl-1 graft-modified with an unsaturated carboxylic acid or the like. A pentene-based copolymer resin, an olefin-based adhesive resin composed of a 4-methyl-1-pentene-based copolymer and an α-olefin-based copolymer, and the like are preferable. When the release layer A (or the release layer A′) contains a fluororesin, the adhesive layer is preferably a polyester-based, acrylic-based, fluororubber-based adhesive or the like. The thickness of the adhesive layer is not particularly limited as long as the adhesiveness between the release layer A (or the release layer A′) and the heat resistant resin layer B can be improved, but is, for example, 0.5 to 10 μm.

The total thickness of the release film for process of the present invention is not particularly limited, but it is preferably, for example, 10 to 300 μm, more preferably 30 to 150 μm. When the total thickness of the release film is within the above range, the handling property when used as a roll is good and the amount of the film discarded is small, which is preferable.

Hereinafter, preferred embodiments of the release film for process of the present invention will be described more specifically. FIG. 1 is a schematic view showing an example of a process release film having a three-layer structure. As shown in FIG. 1, the release film 10 includes a heat-resistant resin layer 12 and a release layer 16 formed on one surface of the release film 10 with an adhesive layer 14 interposed therebetween.

The release layer 16 is the release layer A described above, the heat-resistant resin layer 12 is the heat-resistant resin layer B described above, and the adhesive layer 14 is the adhesive layer described above. The release layer 16 is preferably arranged on the side in contact with the sealing resin in the sealing process; the heat-resistant resin layer 12 is preferably arranged on the side in contact with the inner surface of the mold in the sealing process.

FIG. 2 is a schematic view showing an example of a process release film having a five-layer structure. Members having the same functions as those in FIG. 1 are designated by the same reference numerals. As shown in FIG. 2, the release film 20 includes a heat resistant resin layer 12 and release layers 16A and 16B formed on both surfaces of the release film 20 with an adhesive layer 14 interposed therebetween. The release layer 16A is the above-mentioned release layer A, the heat-resistant resin layer 12 is the above-mentioned heat-resistant resin layer B, the release layer 16B is the above-mentioned release layer A', and the adhesive layer 14 is each the above-mentioned. It is an adhesive layer.

The composition of the release layers 16A and 16B may be the same or different from each other. The release layers 16A and 16B may also have the same or different thicknesses. However, it is preferable that the release layers 16A and 16B have the same composition and the same thickness, because the release layers 16A and 16B have a symmetrical structure and warp of the release film itself is less likely to occur. In particular, since the release film of the present invention may generate stress due to heating in the sealing process, it is preferable to suppress warpage. Thus, it is preferable that the mold release layers 16A and 16B are formed on both surfaces of the heat resistant resin layer 12 because good mold releasability can be obtained on both the molded product and the inner surface of the mold.

Method for Manufacturing Release Film for Process The release film for process of the present invention can be manufactured by any method. For example, 1) a method for producing a release film for process by coextrusion molding and laminating a release layer A and a heat-resistant resin layer B (coextrusion forming method), 2) on a film to be the heat-resistant resin layer B To the release layer A or the adhesive layer by applying a molten resin of the resin, or by applying and drying a resin solution in which the release layer A or the adhesive layer resin is dissolved in a solvent, Method for producing release film for process (coating method), 3) A film to be the release layer A and a film to be the heat-resistant resin layer B are produced in advance, and these films are laminated (laminated). Depending on the method, there is a method of manufacturing a release film for process (laminating method).

In the method 3), various known laminating methods can be adopted as a method of laminating the respective resin films, and examples thereof include an extrusion laminating method, a dry laminating method, and a thermal laminating method.
In the dry laminating method, each resin film is laminated using an adhesive. As the adhesive, a known adhesive for dry lamination can be used. For example, polyvinyl acetate adhesives; homopolymers or copolymers of acrylic acid esters (ethyl acrylate, butyl acrylate, acrylic acid 2-ethylhexyl ester, etc.), or acrylic acid esters and other monomers (methacrylic acid). Methyl, acrylonitrile, styrene, etc.) polyacrylic ester adhesives such as copolymers; cyanoacrylate adhesives; ethylene and other monomers (vinyl acetate, ethyl acrylate, acrylic acid, methacrylic acid) Etc.) ethylene copolymer-based adhesive consisting of a copolymer or the like; cellulose-based adhesive; polyester-based adhesive; polyamide-based adhesive; polyimide-based adhesive; urea resin or melamine resin-based amino resin-based adhesive Adhesives; phenolic resin adhesives; epoxy adhesives; polyurethane adhesives that crosslink polyols (polyether polyols, polyester polyols, etc.) with isocyanates and/or isocyanurates; reactive (meth)acrylic adhesives Rubber adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc.; Silicone adhesives; Inorganic adhesives made of alkali metal silicate, low melting point glass, etc.; Other adhesives can be used. As the resin film laminated by the method 3), a commercially available resin film may be used, or a resin film manufactured by a known manufacturing method may be used. The resin film may be subjected to surface treatment such as corona treatment, atmospheric pressure plasma treatment, vacuum plasma treatment, and primer coating treatment. The method for producing the resin film is not particularly limited, and a known production method can be used.

1) The co-extrusion molding method is preferable in that defects such as foreign matter being caught between the resin layer serving as the release layer A and the resin layer serving as the heat-resistant resin layer and warpage of the release film are unlikely to occur. .. 3) The laminating method is a suitable manufacturing method when a stretched film is used for the heat-resistant resin layer B. In this case, it is preferable to form an appropriate adhesive layer at the interface between the films, if necessary. In order to improve the adhesiveness between the films, the interface between the films may be subjected to a surface treatment such as corona discharge treatment, if necessary.

The release film for process may be uniaxially or biaxially stretched, if necessary, whereby the film strength of the film can be increased.

The coating means in the above 2) coating method is not particularly limited, but various coaters such as a roll coater, a die coater and a spray coater are used. The melt extrusion means is not particularly limited, but for example, an extruder having a T-shaped die or an inflation die is used.

Manufacturing Process The release film for process of the present invention can be used by disposing it between the semiconductor chip and the like and the inner surface of the mold when the semiconductor chip and the like are arranged in the mold and resin is injected and molded. .. By using the release film for process of the present invention, it is possible to effectively prevent the release failure from the mold, the occurrence of burrs, and the like.
The resin used in the above manufacturing process may be either a thermoplastic resin or a thermosetting resin, but thermosetting resins are widely used in the technical field, and in particular, an epoxy thermosetting resin is used. It is preferable to use.
The most typical manufacturing process is encapsulation of a semiconductor chip, but the present invention is not limited to this, and the present invention can also be applied to a fiber-reinforced plastic molding process, a plastic lens molding process, or the like. ..

3, 4A and 4B are schematic views showing an example of a method for producing a resin-encapsulated semiconductor using the release film of the present invention.
As shown in FIG. 3a, the release film 1 of the present invention is supplied from a roll-shaped roll into the molding die 2 by the roll 1-2 and the roll 1-3. Next, the release film 1 is placed on the inner surface of the upper mold 2. If necessary, the inner surface of the upper mold 2 may be evacuated to bring the release film 1 into close contact with the inner surface of the upper mold 2. The semiconductor chip 6 arranged on the substrate is arranged in the lower mold 5 of the molding machine, and the sealing resin is arranged on the semiconductor chip 6, or the liquid sealing resin is so arranged as to cover the semiconductor chip 6. Is injected, the sealing resin 4 is housed between the upper mold 2 and the lower mold 5 in which the release film 1 suctioned by exhaust gas and arranged in close contact is arranged. Next, as shown in FIG. 3B, the upper mold 2 and the lower mold 5 are closed via the release film 1 of the present invention, and the sealing resin 4 is cured.

As a result of the mold closing and curing, the sealing resin 4 is fluidized into the mold as shown in FIG. 3C, the sealing resin 4 flows into the space and is filled so as to surround the side surface of the semiconductor chip 6 and sealed. The upper mold 2 and the lower mold 5 open the chip 6 and take out the chip 6. After the mold is opened and the molded product is taken out, the release film 1 is repeatedly used a plurality of times or a new release film is supplied and the mold is subjected to the next resin molding molding.

The release film of the present invention is brought into close contact with the upper mold, and is interposed between the mold and the sealing resin to prevent the resin from adhering to the mold and stain the resin mold surface of the mold. In addition, the molded product can be easily released from the mold.
The release film may be newly supplied and resin-molded for each resin molding operation, or may be newly supplied and resin-molded for each resin molding operation.

The encapsulating resin may be a liquid resin or a solid resin at room temperature, but an encapsulating material such as one that becomes liquid during resin encapsulation may be appropriately adopted. As the encapsulating resin material, specifically, an epoxy type (a biphenyl type epoxy resin, a bisphenol epoxy resin, an o-cresol novolac type epoxy resin, etc.) is mainly used, and as an encapsulating resin other than the epoxy resin, a polyimide type resin ( It is possible to use those normally used as a sealing resin such as a bismaleimide type) and a silicone type resin (thermosetting type). The resin encapsulation conditions vary depending on the encapsulating resin used, but may be appropriately set within a range of, for example, a curing temperature of 120° C. to 180° C., a molding pressure of 10 to 50 kg/cm ² , and a curing time of 1 to 60 minutes. it can.

The step of arranging the release film 1 on the inner surface of the molding die 8 and the step of arranging the semiconductor chip 6 in the molding die 8 are not particularly limited and may be performed at the same time. The release film 1 may be arranged after the arrangement, or the semiconductor chip 6 may be arranged after the release film 1 is arranged.

In this way, since the release film 1 has the release layer A (and the release layer A'if desired) having high release properties, the semiconductor package 4-2 can be easily released. Further, since the release film 1 has appropriate flexibility, it has excellent followability with respect to the shape of the mold, but is unlikely to be wrinkled by the heat of the molding die 8. Therefore, a wrinkle is not transferred to the resin-sealed surface of the sealed semiconductor package 4-2, and a portion not filled with the resin (resin chipping) does not occur, and the sealed semiconductor package has a good appearance. 4-2 can be obtained.

Further, not only the compression molding method of pressurizing and heating the solid encapsulating resin material 4 as shown in FIG. 3, but also the transfer molding method of injecting the encapsulating resin material in a fluid state as described later is adopted. Good.

4A and 4B are schematic views showing a transfer molding method which is an example of a method for producing a resin-sealed semiconductor using the release film of the present invention.

As shown in FIG. 4A, the release film 22 of the present invention is supplied from a roll-shaped roll into the molding die 28 by the roll 24 and the roll 26 (step a). Next, the release film 22 is placed on the inner surface 30A of the upper mold 30 (step b). If necessary, the upper mold inner surface 30A may be evacuated to bring the release film 22 into close contact with the upper mold inner surface 30A. Next, the semiconductor chip 34 to be resin-sealed (semiconductor chip 34 fixed to the substrate 34A) is placed in the molding die 28, and the sealing resin material 36 is set (step c), and the mold is clamped (step c). Step d).

Next, as shown in FIG. 4B, the sealing resin material 36 is injected into the molding die 28 under predetermined heating and pressurizing conditions (step e). At this time, the temperature of the molding die 28 (molding temperature) is, for example, 165 to 185° C., the molding pressure is, for example, 7 to 12 MPa, and the molding time is, for example, about 90 seconds. Then, after holding for a certain period of time, the upper mold 30 and the lower mold 32 are opened, and the resin-sealed semiconductor package 40 and the release film 22 are released simultaneously or sequentially (step f).

Then, as shown in FIG. 5, a desired semiconductor package 44 can be obtained by removing an excess resin portion 42 of the obtained semiconductor package 40. The release film 22 may be used as it is for resin encapsulation of other semiconductor chips, but each time molding is completed, the roll is operated to feed the film, and the release film 22 is newly molded. 28 is preferably supplied.

The step of arranging the release film 22 on the inner surface of the molding die 28 and the step of arranging the semiconductor chip 34 in the molding die 28 are not particularly limited and may be performed at the same time. The release film 22 may be placed after the placement, or the semiconductor chip 34 may be placed after the release film 22 is placed.

In this way, the release film 22 has the release layer A (and the release layer A′ if desired) having high release properties, so that the semiconductor package 40 can be easily released. Further, since the release film 22 has appropriate flexibility, it has excellent followability with respect to the shape of the mold, but is unlikely to be wrinkled by the heat of the molding mold 28. Therefore, it is possible to obtain the semiconductor package 40 having a good appearance, without wrinkles being transferred to the resin-sealed surface of the semiconductor package 40 or a portion not filled with the resin (resin chip).

The release film of the present invention is not limited to the step of resin-sealing a semiconductor element, but a step of molding and releasing various molded articles using a molding die, for example, fiber-reinforced plastic molding and release step, plastic lens molding. Also, it can be preferably used in the mold releasing step and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

In the following examples/comparative examples, the evaluation of physical properties/characteristics was performed by the following methods.
(Thermal dimensional change rate)
A film sample is cut out in a length (MD) direction and a width (MD) direction of the film to a length of 20 mm and a width of 4 mm, and using TA Instruments TMA (thermomechanical analyzer, product name: Q400), a chuck distance of 8 mm After holding for 5 minutes at 23° C. under a load of 0.005 N, the temperature is raised from 23° C. to 120° C. at a heating rate of 10° C./min, and the dimensional change in each direction is measured. The dimensional change rate was calculated according to (1).

Thermal dimensional change rate (%) (23→120° C.)={[(L ₂ −L ₁ )/L ₁ ]×100}
...(1)
L ₁ : Sample length at 23°C (mm)
L ₂ : Sample length at 120°C (mm)

Similarly, the temperature was raised from 23° C. to 170° C. at a heating rate of 10° C./min, the dimensional change in each direction was measured, and the dimensional change rate was calculated by the following formula (2).

Thermal dimensional change rate (%) (23→170° C.)={[(L ₃ −L ₁ )/L ₁ ]×100}
...(2)
L ₁ : Sample length at 23°C (mm)
L ₃ : Sample length at 170°C (mm)

Contact angle to water (water contact angle)
According to JIS R3257, the water contact angle of the surface of the release layer A was measured using a contact angle measuring device (FACECA-W manufactured by Kyowa Interface Face Science).
(Tensile modulus)
Method of Measuring Tensile Elastic Modulus Based on JIS K7127, the tensile elastic moduli at 23° C., 120° C. and 170° C. were obtained.
Measuring conditions: Tensile mode Measuring direction: Film longitudinal (MD) direction (film transport direction)

(Surface resistivity value)
A 10×10 cm test piece cut out from the obtained release film was stored at a temperature of 23° C. and a humidity of 50% RH for 24 hours. After that, an applied voltage was measured at 0.10 V, a temperature of 23° C., and a humidity of 50% RH using a digital ultra-high resistance/trace ammeter (8340A) manufactured by Advantest and a resistency chamber (R12704).

(Ash adhesion test)
The antistatic property of the release film is determined by rubbing the release film with a polyester fiber cloth 10 times in an atmosphere of 20° C. and 50% RH, and then checking the adhesion of ash.
No adhesion: ○
Significant adhesion: ×
And

(Melting point (Tm), heat of crystal fusion)
Using a Q100 manufactured by TA Instruments as a differential scanning calorimeter (DSC), about 5 mg of a polymer sample was precisely weighed, and in accordance with JISK7121, a nitrogen gas inflow rate: 50 ml/min under a condition of 25 The melting point (Tm) and the crystal heat of fusion of the sample were determined from the obtained thermal melting curve by heating from ℃ to 280° C. at a heating rate of 10° C./min.

(Releasability)
As shown in FIG. 3, the process release films produced in the respective examples/comparative examples were arranged with a tension of 10 N applied between the upper mold and the lower mold, and then the upper mold was parted. The surface was vacuum-adsorbed. Next, after filling the substrate with a sealing resin so as to cover the semiconductor chip, the semiconductor chip fixed to the substrate was placed in the lower mold and clamped. At this time, the temperature of the molding die (molding temperature) was 120° C., the molding pressure was 10 MPa, and the molding time was 400 seconds. Then, as shown in FIG. 3C, after the semiconductor chip was sealed with a sealing resin, the resin-sealed semiconductor chip (semiconductor package) was released from the release film.
The releasability of the release film was evaluated according to the following criteria.
◯: The release film spontaneously peels off when the mold is opened.
Δ: The release film does not peel off naturally, but it easily peels off when pulled by hand (when tension is applied).
X: The release film is in close contact with the resin-sealed surface of the semiconductor package and cannot be peeled off by hand.

(Appearance of molded product)
The appearance of the release film and the resin-sealed surface of the semiconductor package after the release was performed in the above steps was evaluated according to the following criteria.
◯: Both the release film and the semiconductor package have no wrinkles, and there is no burr on the outer periphery of the semiconductor package.
Δ: Both the release film and the semiconductor package have no wrinkles or slight wrinkles, and the outer periphery of the semiconductor package has slight burrs.
X: The semiconductor film as well as the release film has many wrinkles, or the outer peripheral portion of the semiconductor package has many burrs.

(Mold followability)
The mold followability of the release film when the release was performed in the above process was evaluated according to the following criteria.
◯: There is no resin chipping (portion not filled with resin) in the semiconductor package.
△: Slight resin chipping at the edge of the semiconductor package (excluding wrinkle chips) X: Many resin chipping at the edge of the semiconductor package (excluding wrinkle chips)

[Example 1]
As the base material B0a of the heat-resistant resin layer B, a biaxially stretched PET (polyethylene terephthalate) film having a thickness of 12 μm (manufactured by Toray Industries, Inc., product name: Lumirror S10) was used.
A PEDOT polythiophene resin (manufactured by Kaken Sangyo Co., Ltd., product name: MC-200) was used as the antistatic resin a, and a layer containing a polymer antistatic agent was formed. More specifically, the antistatic resin a is coated on one surface of the base material B0a of the heat resistant resin layer B at a coating amount of 0.1 g/m ² and dried to form a layer B1a containing a polymeric antistatic agent. Formed.
The rate of thermal dimensional change from 23° C. to 120° C. of the biaxially stretched PET film (heat resistant resin layer Ba) provided with the layer containing the polymer antistatic agent obtained above was − in the machine direction (MD) direction. It was 0.1% and 0.6% in the transverse (TD) direction. The melting point of the biaxially stretched PET film was 258°C, and the heat of crystal fusion was 39.4 J/g.

As the release layers A and A′, unstretched 4-methyl-1-pentene copolymer resin film Aa (A′a) was used. Specifically, a 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022) manufactured by Mitsui Chemicals, Inc. was used to form an unstretched film having a thickness of 15 μm. (Melting point: 229° C., heat of crystal fusion: 21.7 J/g)
The unstretched 4-methyl-1-pentene copolymer resin film has an adhesive property improved by an adhesive so that one film surface has a water contact angle of 30° or more based on JIS R3257 of 30 or less. Corona treatment was applied from the viewpoint.
The thermal dimensional change rate of the 4-methyl-1-pentene copolymer resin film Aa from 23° C. to 120° C. was 6.5% in the longitudinal (MD) direction and 3.1% in the transverse (TD) direction. It was

(adhesive)
The following urethane-based adhesive α was used as the adhesive used in the dry laminating step of bonding the films.
[Urethane adhesive α]
Main agent: Takelac A-616 (manufactured by Mitsui Chemicals, Inc.). Hardening agent: Takenate A-65 (manufactured by Mitsui Chemicals, Inc.). The main agent and the curing agent were mixed so that the mass ratio (main agent: curing agent) was 16:1, and ethyl acetate was used as a diluent.

(Production of release film)
The biaxially stretched PET film (heat-resistant resin layer Ba) provided with the antistatic layer was coated with urethane adhesive α at 1.5 g/m ² by gravure coating, and unstretched 4-methyl -1-After the corona-treated surface of the 1-pentene copolymer resin film Aa was laminated by dry lamination, the urethane adhesive α was added to the biaxially stretched PET film surface side of this laminated film at 1.5 g/m ² And the corona-treated surface of the unstretched 4-methyl-1-pentene copolymer resin film A'a is laminated by dry lamination to form a five-layer structure (release layer A/adhesive layer/heat-resistant resin layer). A process release film of B/adhesive layer/release layer A′) was obtained.
The dry laminating conditions were a substrate width of 900 mm, a conveying speed of 30 m/min, a drying temperature of 50 to 60° C., a laminating roll temperature of 50° C., and a roll pressure of 3.0 MPa.

The thermal dimensional change rate from 23° C. to 120° C. of the release film for the process was 1.0% in the machine direction (MD) and 1.4% in the transverse (TD) direction.
Table 1 shows the tensile elastic modulus, releasability, appearance of the molded product, mold followability, surface resistivity, and ash adhesion test evaluation results. The release film shows good releasability that spontaneously peels off when the mold is opened, and neither the release film nor the semiconductor package has wrinkles or burrs, that is, wrinkles are sufficiently suppressed, and the semiconductor package has It showed good mold followability without any resin chipping. That is, the process release film of Example 1 was a process release film having good mold releasability, appearance of the molded article, and mold followability. Moreover, ash adhesion was not observed.

[Examples 2 to 9]
A release film for process was produced in the same manner as in Example 1 except that the film configuration shown in Table 1 was used, and sealing and release were performed, and the characteristics were evaluated. The results are shown in Table 1.
The details of the polymeric antistatic agents b to e and the layers B1b to B1e containing the same shown in Table 1 are as follows.
As the antistatic resin b, PEDOT polythiophene resin (manufactured by Chukyo Yushi Co., Ltd., product name: S-495) was used to form a layer containing a polymer antistatic agent. More specifically, the antistatic resin b is applied to one surface of the base material B0a or the like of the heat-resistant resin layer B at a coating amount of 0.3 g/m ² and dried to contain a polymeric antistatic agent. B1b was formed. The rate of thermal dimensional change from 23° C. to 120° C. of the biaxially stretched PET film provided with the layer containing the polymer antistatic agent obtained above was the result shown in Table 1.
As the antistatic resin c, a PEDOT polythiophene resin (manufactured by Nagase & Co., product name: P-530RL) was used to form a layer containing a polymer antistatic agent. More specifically, the antistatic resin c is applied to one surface of the base material B0a or the like of the heat resistant resin layer B at a coating amount of 0.1 g/m ² and dried to contain a polymeric antistatic agent. B1c was formed. The rate of thermal dimensional change from 23° C. to 120° C. of the biaxially stretched PET film provided with the layer containing the polymer antistatic agent obtained above was the result shown in Table 1.
As the antistatic resin d, a quaternary ammonium salt-containing resin (manufactured by Taisei Fine Chemical Co., product name: 1SX-1090) was used to form a layer containing a polymeric antistatic agent. More specifically, the antistatic resin d is applied to one surface of the base material B0a of the heat-resistant resin layer B at a coating amount of 0.4 g/m ² and dried to contain a polymeric antistatic agent. B1d was formed. The rate of thermal dimensional change from 23° C. to 120° C. of the biaxially stretched PET film provided with the layer containing the polymer antistatic agent obtained above was the result shown in Table 1.
As the antistatic resin e, an anionic synthetic clay mineral-containing polyester resin (manufactured by Takamatsu Yushi Co., Ltd., product name: ASA-2050) was used to form a layer containing a polymer antistatic agent. Specifically, the antistatic resin e is applied to one surface of the base material B0a or the like of the heat resistant resin layer B at a coating amount of 0.4 g/m ² and dried to form a layer B1e containing a polymer antistatic agent. Formed.

An anionic synthetic clay mineral-containing polyester resin (manufactured by Takamatsu Yushi Co., Ltd., product name: ASA-2050) was used to form a layer containing a polymer antistatic agent. Specifically, the antistatic resin e is applied to one surface of the base material B0a or the like of the heat resistant resin layer B at a coating amount of 0.4 g/m ² and dried to form a layer B1e containing a polymer antistatic agent. Formed. Table 1 shows the test items such as the thermal dimensional change rate from 23° C. to 120° C., the water contact angle, and the evaluation results of the biaxially stretched PET film provided with the layer containing the polymer antistatic agent obtained above. It was as shown.

In all of the examples, the mold release film was good in all the test items of the mold release property, the appearance of the molded product, the mold followability, and the ash adhesion test, and the process release film was well balanced in terms of performance.

The details of each film shown in Table 1 are as follows.
(Aa) Unstretched 4MP-1 (TPX) film A non-stretched film having a thickness of 15 μm was formed using 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 229° C., heat of crystal fusion: 21.7 J/g)
(Ab) Non-stretched 4MP-1 (TPX) film A non-stretched film having a thickness of 50 μm was formed using 4-methyl-1-pentene copolymer resin (product name: TPX, brand name: MX022) manufactured by Mitsui Chemicals, Inc. What I did. (Melting point: 229° C., heat of crystal fusion: 21.7 J/g)
(B0a) Biaxially Stretched PET Film A 12 μm thick biaxially stretched PET (polyethylene terephthalate) film (manufactured by Toray Industries, Inc., product name: Lumirror S10) (melting point: 258° C., heat of crystal fusion: 39.4 J/g).
(B0b) Biaxially Stretched Nylon Film A biaxially stretched nylon film having a thickness of 15 μm (manufactured by Kojin Film & Chemicals Co., Ltd., product name: Bonyl RX) (melting point: 212° C., heat of crystal fusion: 53.1 J/g)
(B0c) Biaxially Stretched Polypropylene Film Biaxially stretched polypropylene film having a thickness of 20 μm (manufactured by Mitsui Chemicals Tohcello Co., Ltd., product name: U-2) (melting point: 160° C., heat of fusion of crystal: 93.3 J/g)
(B0d) Unstretched Nylon Film Unstretched nylon film with a film thickness of 20 μm (manufactured by Mitsubishi Plastics Co., Ltd., product name: Dynamilon C) (melting point: 220° C., heat of crystal fusion: 39.4 J/g)
(B0e) Non-Stretched Polybutylene Terephthalate Film A film obtained by forming a non-stretched film having a thickness of 20 μm using a polybutylene terephthalate resin (brand name: 5505S) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 219° C., heat of crystal fusion: 48.3 J/g)
(B0f) Non-Stretched Polybutylene Terephthalate Film A film obtained by forming a non-stretched film having a thickness of 50 μm using a polybutylene terephthalate resin (brand name: 5505S) manufactured by Mitsubishi Engineering Plastics Co., Ltd. (Melting point: 219° C., heat of crystal fusion: 48.3 J/g)

[Comparative Examples 1 to 3]
The characteristics of the release film for process were evaluated by sealing and releasing in the same manner as in Example 1 except that the film constitution shown in Table 1 was adopted.
In all of the comparative examples, the overall performance was below that of the examples, and the ash adhesion test results were particularly poor. Furthermore, with regard to the appearance, good results were not obtained except for Comparative Example 1.

[Examples 10 to 17]
A release film for process was prepared in the same manner as in Example 1 except that each film shown in Table 2 was used as the release layers A and A′ and the heat-resistant resin layer B in the combination shown in Table 2, and sealing and release were performed. Molding was done and the properties were evaluated.
As shown in FIG. 3a, the release film was placed between the upper mold and the lower mold with a tension of 20 N applied, and then vacuum-adsorbed on the parting surface of the upper mold. Next, after filling the substrate with a sealing resin so as to cover the semiconductor chip, the semiconductor chip fixed to the substrate was placed in the lower mold and clamped. At this time, the temperature of the molding die (molding temperature) was 170° C., the molding pressure was 10 MPa, and the molding time was 100 seconds. Then, as shown in FIG. 3C, after the semiconductor chip was sealed with a sealing resin, the resin-sealed semiconductor chip (semiconductor package) was released from the release film. The results are shown in Table 2.
Despite the evaluation of the high temperature range at 170° C., all of the examples have good mold releasability, appearance of the molded product, and mold followability, and are good in all the test items of the ash adhesion test, and are balanced in terms of performance. It was a release film for process that was able to be removed. In particular, Examples 15 to 17 were mold release films for processes, which had good mold releasability, appearance of molded products, mold followability, and ash adhesion test results.

[Comparative Examples 4 to 9]
A process release film was produced in the same manner as in Examples 10 to 17 except that the film configuration shown in Table 2 was used, and sealing and releasing were performed, and the characteristics were evaluated. The results are shown in Table 2.
In all of the comparative examples, the overall performance was below that of each example, and particularly no good results were obtained in both the appearance of the molded product and the ash adhesion test.

The details of each film shown in Table 2 are the same as those described above for each film shown in Table 1.
Details of the base materials B0g and B0h of the heat-resistant resin layer described only in Table 2 are as follows.
(B0g) Biaxially Stretched Nylon Film A biaxially stretched nylon film having a thickness of 15 μm (manufactured by Idemitsu Unitech Co., Ltd., product name: Unilon S330) (melting point: 221° C., heat of crystal fusion: 60.3 J/g)
(B0h) Biaxially Stretched PET Film A 25 μm thick biaxially stretched PET film (manufactured by Teijin DuPont Films, product name: FT3PE) (melting point: 214° C., heat of fusion of crystal: 40.3 J/g).

Since the release film for process of the present invention has a high level of releasability, wrinkle suppression, and mold followability, which cannot be realized by the prior art, by using this, a semiconductor chip or the like is resin-sealed. A product that has a practically high technical value that can be easily released from a molded product obtained by, for example, and that can produce a molded product that does not have a defective appearance such as wrinkles or chips with high productivity. Therefore, it has high availability in various fields of industry including the semiconductor process industry.
Further, the release film for process of the present invention can be used not only for semiconductor packages but also for various mold forming in fiber reinforced plastic molding process, plastic lens molding process, etc. It also has high availability in various fields of industry.

1, 1-2, 1-3: Release film 2: Upper mold 3: Suction port 4: Sealing resin 4-2: Semiconductor package 5: Lower mold 6: Semiconductor chip 7: Substrate 8: Molding mold 10, 20, 22: Release film 12: Heat-resistant resin layer B
14: Adhesive layers 16 and 16A: Release layer A
16B: Release layer A'
24 and 26: Roll 28: Mold 30: Upper mold 32: Lower mold 34: Semiconductor chip 34A: Substrate 36: Sealing resin 40, 44: Semiconductor package

Claims (24)

A release film for process, which is a laminated film including a release layer A and a heat-resistant resin layer B,
The release layer A has a contact angle with water of 90° to 130°,
The heat-resistant resin layer B includes a layer B1 containing a polymeric antistatic agent,
Ri 500MPa der tensile modulus from 75MPa at 120 ° C. of the laminated film, Ru 500MPa der tensile modulus from 85MPa at 170 ° C., a release film for the above process. The process release film according to claim 1, wherein a thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction of the laminated film is 3% or less. The sum of the thermal dimensional change rate from 23°C to 120°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 120°C in the longitudinal (MD) direction of the laminated film is 6% or less. The release film for process according to 1 or 2. The process release film according to any one of claims 1 to 3 , wherein a thermal dimensional change rate from 23°C to 170°C in the transverse (TD) direction of the laminated film is 4% or less. The sum of the thermal dimensional change rate from 23°C to 170°C in the transverse (TD) direction and the thermal dimensional change rate from 23°C to 170°C in the longitudinal (MD) direction of the laminated film is 7% or less. The release film for process according to any one of 1 to 4 . The process release layer according to any one of claims 1 to 5 , wherein the heat-resistant resin layer B comprises a layer B1 containing a polymeric antistatic agent and an adhesive layer B2 containing an adhesive. Type film. The process release film according to any one of claims 1 to 5 , wherein the heat-resistant resin layer B comprises a layer B3 containing a polymeric antistatic agent and an adhesive. The release film for process according to any one of claims 1 to 7 , wherein the heat-resistant resin layer B has a rate of thermal dimensional change in the lateral (TD) direction from 23°C to 120°C of 3% or less. The sum of the thermal dimensional change rate from 23° C. to 120° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 120° C. in the longitudinal (MD) direction of the heat resistant resin layer B is 6% or less. The release film for process according to claim 8 . The release film for process according to any one of claims 1 to 7 , wherein the heat-resistant resin layer B has a lateral (TD) direction thermal dimensional change rate from 23°C to 170°C of 3% or less. The sum of the thermal dimensional change rate from 23° C. to 170° C. in the transverse (TD) direction and the thermal dimensional change rate from 23° C. to 170° C. in the longitudinal (MD) direction of the heat-resistant resin layer B is 5% or less. The release film for process according to claim 10 . The release layer A is a fluororesin, 4-methyl-1-pentene (co) polymer, and a resin selected from the group consisting of polystyrene resin, according to any one of claims 1 to 11 Release film for process. The release film for process according to any one of claims 1 to 12 , wherein the heat-resistant resin layer B comprises a stretched film. The process release film according to claim 13 , wherein the stretched film is selected from the group consisting of a stretched polyester film, a stretched polyamide film, and a stretched polypropylene film. The heat of crystal fusion of 20 J/g or more and 100 J/g or less in the first temperature raising step measured by differential scanning calorimetry (DSC) according to JIS K7221 of the heat-resistant resin layer B, any one of claims 1 to 14 . The release film for process according to the item 1. Surface resistivity is 1 × 10 ¹³ Ω / □ or less, the process for release film according to any one of claims 1 to 15 of the releasing layer A. The laminated film further has a release layer A′, and includes the release layer A, the heat-resistant resin layer B, and the release layer A′ in this order,
The process release film according to any one of claims 1 to 16 , wherein a contact angle of the release layer A′ with water is 90° to 130°. At least one of the release layer A and the release layer A 'comprises a fluorine resin, 4-methyl-1-pentene (co) polymer, and resin selected from the group consisting of polystyrene resin, according to claim 17 The release film for process according to. The process release film according to claim 17 or 18 , wherein the surface specific resistance value of the release layer A′ is 1×10 ¹³ Ω/□ or less. The process release film according to any one of claims 1 to 19 , which is used in a sealing process using a thermosetting resin. Used in semiconductor encapsulation process, a release film for the process according to any one of claims 1 20. The process release film according to any one of claims 1 to 20 , which is used in a fiber-reinforced plastic molding process or a plastic lens molding process. A method of manufacturing a resin-encapsulated semiconductor,
A step of disposing a resin-sealed semiconductor device at a predetermined position in a molding die,
Disposing the release film for semiconductor encapsulation process according to any one of claims 1 to 21 on the inner surface of the molding die such that the release layer A faces the semiconductor device.
After clamping the molding die, a step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process,
A method of manufacturing the above resin-encapsulated semiconductor, comprising: A method of manufacturing a resin-encapsulated semiconductor,
A step of disposing a resin-sealed semiconductor device at a predetermined position in a molding die,
A step of disposing the release film for semiconductor encapsulation process according to any one of claims 17 to 19 on the inner surface of the molding die so that the release layer A′ faces the semiconductor device,
After clamping the molding die, a step of injecting and molding a sealing resin between the semiconductor device and the release film for the semiconductor sealing process,
A method of manufacturing the above resin-encapsulated semiconductor, comprising: