JP6738672B2 - Release film and method for manufacturing semiconductor package - Google Patents

Description

The present invention relates to a release film and a method for producing a resin molded product.

A release film is used to prevent the resin from adhering to a mold or roll when manufacturing printer boards, sealing parts for electronic devices such as ceramic electronic components and semiconductor packages, or other various resin products. There is.
As a material for the release film, a material having a high releasability due to its properties and having heat resistance to withstand the molding temperature is used. For example, ethylene-tetrafluoroethylene copolymer (ETF
It is known to use a fluorine-based resin such as E) as a release film. Patent Document 1 discloses that a biaxially oriented polystyrene film containing a syndiotactic polystyrene (SPS) resin and an antioxidant is used as a release film.

JP-A-2015-21017

However, depending on the resin, the release film may adhere to the resin molded product even if the release film as described above is used.
It is an object of the present invention to provide a new method for producing a resin molded product obtained by molding a resin having such high adhesiveness and adhesiveness. And it aims at providing the release film preferably used for such a manufacturing method.

The release film of the present invention is a release film for use in resin molding, comprising a support layer having releasability and a temporary transfer layer provided on one surface of the support layer, wherein the temporary transfer layer is , At least a part of which is transferred to the resin molded product and removed from the resin molded product.
The release film of the present invention is used by being interposed between a resin and a molding die (for example, a metal die, a resin die) or a roll. Therefore, when the resin is molded with the molding die or roll, the resin and the molding die or roll do not come into contact with each other. Further, since only the temporary transfer layer is transferred to the resin molded product, it can be easily removed from the resin molded product. This release film is suitable for molding a resin having high adhesiveness and adhesiveness with a molding die or roll.

In the release film of the present invention, when the thickness of the temporary transfer layer is 35 μm or less, it is easier to remove the temporary transfer layer after being transferred to the resin molded product.
In the release film of the present invention, when the support layer has a biaxially oriented SPS polymer film, it has excellent release properties, heat resistance and chemical resistance.

The method for producing a resin molded article of the present invention comprises a step of preparing a release film having a support layer having releasability and a temporary transfer layer provided on one surface of the support layer, and via the release film. Forming a resin, a step of transferring at least a part of the temporary transfer layer of the release film to a resin molded article, and a step of removing the temporary transfer layer transferred to the resin molded article. It has a feature.
INDUSTRIAL APPLICABILITY The resin molded product manufacturing method of the present invention can reduce wear of the molding die without complicating the manufacturing process. In particular, it is suitable for molding a resin having poor mold releasability and high adhesiveness/adhesiveness with a molding die.

The step of molding the resin of the present invention is preferably a step of molding the resin with a molding die or roll.
The step of removing the temporary transfer layer of the present invention is preferably a step of removing the temporary transfer layer by polishing, blasting or washing. In this case, the process of removing the temporary transfer layer can be simplified. In particular, when the resin molded product is an electronic device including a resin sealing portion, after the molding of the sealing portion, a polishing step of the sealing portion surface for thinning, a polishing step for exposing the connection electrode, and the like, The release film of the present invention can be used as the removal of the temporary transfer layer, and the release film of the present invention can be used in the conventional manufacturing process without increasing the number of processes.

FIG. 1a is a side view showing an embodiment of the release film of the present invention, and FIG. 1b is a side view showing another embodiment of the release film of the present invention. 2a, 2b, and 2c are schematic views showing a resin molding step of an embodiment of the method for manufacturing a resin molded product of the present invention. FIG. 3a is a schematic view showing a transfer step of a temporary transfer layer in an embodiment of a method for producing a resin molded product of the present invention, and FIGS. 3b and 3c are other embodiments of a method for producing a resin molded product of the present invention, respectively. FIG. 6 is a schematic view showing a transfer step of the temporary transfer layer of FIG. 4A and 4B are schematic views showing the resin molding process of the embodiment.

As shown in FIG. 1, the release film of this embodiment includes a support layer 11 having releasability and a temporary transfer layer 12 provided on one surface (lower surface in FIG. 1) of the support layer 11.
The release film 10 is a film that is disposed between the resin 20 and the molding die 30 and that molds the resin 20 with the molding die 30 without directly contacting the resin molding surface 30 a of the molding die 30 with the resin 20. (See Figures 2a,b).

The support layer 11 contacts the resin molding surface 30a of the molding die 30. The support layer 11 is a mold 30.
It is excellent in mold releasability and slipperiness, and has toughness that follows the irregularities of the molding die 30.
It also has heat resistance to withstand the molding temperature.
The thickness of the support layer 11 is preferably 20 μm or more, more preferably 25 μm or more, particularly preferably 30 μm or more, preferably 100 μm or less, more preferably 90 μm or less, further preferably 80 μm or less, particularly preferably 75 μm or less. is there. If it is too thin or too thick, manufacturing and handling will be complicated.

As the support layer 11, a styrene-based polymer, a propylene-based polymer, an ethylene-based polymer, a polyester-based resin such as polyethylene terephthalate (PET), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF) or ethylene-tetrafluoroethylene copolymerization Examples thereof include synthetic resin films such as fluorine-based resins such as combined (ETFE).
As the styrene-based polymer, a polymer having a syndiotactic (SPS) structure (
SPS polymers) are preferred. The types of SPS-based polymers include polystyrene, poly(alkylstyrene), poly(halogenated styrene), poly(halogenated alkylstyrene), poly(alkoxystyrene), poly(vinyl benzoate), and hydrogenated polymers thereof. Examples thereof include a coalesced product and a mixture thereof, or a copolymer containing them as a main component. Poly (
Examples of the alkyl styrene) include poly(methylstyrene), poly(ethylstyrene), poly(isopropylstyrene), poly(tertiarybutylstyrene), poly(phenylstyrene), poly(vinylnaphthalene), poly(vinylstyrene), etc. Are listed. Examples of poly(halogenated styrene) include poly(chlorostyrene), poly(bromostyrene), poly(fluorostyrene) and the like. As poly(halogenated alkyl styrene),
Examples thereof include poly(chloromethylstyrene). As poly(alkoxystyrene),
Examples thereof include poly(methoxystyrene) and poly(ethoxystyrene).

The synthetic resin film is preferably biaxially oriented. For example, biaxial orientation can be performed by simultaneously or sequentially stretching. As such a biaxially oriented synthetic resin film, an SPS-based polymer simultaneous (sequential) biaxially stretched film or a PET simultaneous (sequential) biaxially stretched film is preferable, and an SPS-based polymer simultaneous biaxially stretched film is particularly preferable.

On the other hand, like the release film 10a shown in FIG. 1b, the support layer 11 may have a two-layer structure or a multilayer structure of three or more layers. In that case, for example, at least the layer 11a that is in contact with the resin molding surface 30a of the molding die is a layer having excellent releasability and slipperiness with respect to the resin molding surface 30a of the molding die. Then, at least the layer 11b that is in contact with the temporary transfer layer 12 is a layer that is easily separated from the temporary transfer layer 12 or a layer having a small interlayer adhesion strength with the temporary transfer layer 12.

The temporary transfer layer 12 is a layer that contacts the resin 20. Further, the temporary transfer layer 12 is transferred onto the surface of the resin molded product in the process of separating the release film 10 from the resin molded product after molding the resin 20 into the resin molded product, and then removed from the resin molded product.
The interlayer adhesion strength of the temporary transfer layer 12 to the resin 20 is larger than the interlayer adhesion strength of the support layer 11. As a result, after the resin 20 is sealed, the temporary transfer layer 12 is easily peeled off from the support layer 11 and easily transferred to the resin molded product. Further, the temporary transfer layer 12 has a toughness that follows the irregularities of the molding die. Further, it is preferable that the effect of the molding temperature is small. For example, those that do not thermally decompose to generate gas, foam, or become brittle to cause cracks are preferable.
When the temporary transfer layer 12 is removed from the resin molded product by polishing or blasting, the temporary transfer layer 12 preferably has low viscosity and low elasticity. On the other hand, when the temporary transfer layer 12 is removed from the resin molded article by washing with a liquid (water, solvent), the temporary transfer layer 12 is preferably soluble in the liquid (water, solvent).

The thickness of the temporary transfer layer 12 is preferably 35 μm or less, more preferably 25 μm or less, and particularly preferably 15 μm or less. If it is too thick, removal after transfer to a resin molded product becomes complicated. On the other hand, when the resin 20 is too thin, it is difficult to laminate the film, and the resin 20 breaks during resin molding, and the resin 20 becomes a temporary transfer layer 12.
There is a case where it penetrates through the substrate and comes into contact with the support layer 11, so that it is preferably 5 nm or more,
The thickness is more preferably 50 nm or more, and particularly preferably 1 μm or more.
The temporary transfer layer 12 can be laminated on one surface of the support layer 11 by coating, extrusion laminating, thermal laminating, vapor deposition, sputtering, dry laminating, printing or the like.
The material of the temporary transfer layer 12 is appropriately selected according to the materials of the support layer 11 and the resin 20. For example, synthetic resins include polyolefin resins such as polyethylene and polypropylene, polyvinyl alcohol, polyester resins, acrylic resins, polyurethane resins, epoxy resins, polyamide resins, silicone resins, fluorine resins, synthetic rubbers, etc. And modified products and mixtures thereof. Other examples include metals, metal oxides, silica, and various printing inks.

Next, a method for manufacturing the resin molded product of this embodiment will be described.
The method for manufacturing a resin molded product according to the present embodiment includes a step of preparing the release film 10, a step of press-molding the resin 20 with the molding die 30 via the release film 10, and a temporary transfer layer of the release film 10. There is a step of transferring 12 to the resin molded product, and a step of removing the temporary transfer layer 12 transferred to the resin molded product.

2A to 2C show an outline of a step of press-molding the resin 20 with the molding die 30 via the release film 10. In this step, the sealing portion 25 that covers the upper surface of the substrate 15 is formed. Preferably, it is a sealing part of a semiconductor package that seals a substrate on which a semiconductor element is mounted.

As shown in FIG. 2 a, the molding die 30 has an upper molding die 31 and a lower molding die 32. The upper molding die 31 is provided with a recess 31a, and a space is created when the upper molding die 31 and the lower molding die 32 are brought close to each other. The inner surface of the recess 31a becomes the resin molding surface 30a.
Next, as shown in FIG. 2b, the release film 10 is deformed along the recess 31a of the upper molding die 31 and fixed to the upper molding die 31 (lower surface in FIG. 2a). The release film 10 can be fixed, for example, by suctioning from the suction port 31b of the upper molding die 31. On the other hand, the substrate 15 is placed on the lower molding die 32, and the resin 20 is filled on the substrate 15. Thereby, the upper molding die 31
The substrate 15, the resin 20, and the release film 10 are sequentially arranged from the bottom between the lower molding die 32 and the lower molding die 32. The substrate 15 is preferably fixed to the lower molding die 32. The fixing can be performed, for example, by sucking from the suction port 32a of the lower molding die 32.
Then, as shown in FIG. 2c, the resin molding surface 30a of the upper molding die 31 is heated to the molding temperature, and the upper molding die 31 (or the lower molding die 32) is changed to the lower molding die 32 (or the upper molding die 31). The resin 20 is sealed while the space between the upper molding die 31 and the lower molding die 32 is pressed close to each other and the resin 20 is sealed.
Mold to 5. The molding temperature is selected according to the resin 20 to be molded. For example, it is 100°C or higher, preferably 130°C or higher, particularly preferably 150°C or higher, and the upper limit is about 250°C or lower, usually 200°C or lower. For a resin molded at about 130° C. to 200° C., an SPS stretched film, particularly an SPS biaxially stretched film, is preferably used as the support layer 11.

In the manufacturing method of this embodiment, the substrate 15, the resin 20, and the release film 10 are sequentially arranged from the bottom to perform resin molding, but the positional relationship may be upside down. That is, the release film 1
0 may be fixed to the lower mold, the substrate 15 may be fixed to the upper mold, and the resin 20 may be disposed on the release film 10.
In the manufacturing method of this embodiment, the resin 20 is used for compression molding while being compressed by the upper and lower molding dies, but the present invention is not limited to this. For example, it may be used for injection molding or transfer molding in which a space formed between the upper and lower molds is filled with a molten resin or powdery or liquid prepolymer and solidified. Further, it may be used for roll forming. Further, the molding die may use a resin die instead of the metal die.

As the resin 20, epoxy resin, melamine resin, urea resin, alkyd resin,
Examples thereof include thermosetting resins such as polyimide resins, and thermoplastic resins such as polyester resins, polyurethane resins, and acrylic resins. In particular, epoxy resins have low oxygen/moisture permeability and high chemical resistance, and are therefore preferable as sealing parts for electronic devices such as semiconductor packages, printed circuit boards, and ceramic electronic components.
Examples of the resin molded product include a semiconductor package having a sealing portion, a printed circuit board, another electronic device such as a ceramic electronic component, a thermosetting resin product, and a thermoplastic resin product. Particularly, a semiconductor package is preferable. In this embodiment, the semiconductor package in which one side of the substrate is sealed is described, but a semiconductor package in which the entire substrate is sealed may be used.
In that case, a mold release film is sandwiched between the upper mold and the resin, and between the lower mold and the resin to perform resin molding.

Next, a process of transferring the temporary transfer layer 12 of the release film 10 to the resin molded product will be described. That is, after the upper molding die 31 is separated from the lower molding die 32, or at the same time when the upper molding die 31 is separated from the lower molding die 32, the temporary transfer layer 12 of the release film 10 is separated from the resin molded article.
And is transferred to the sealing portion 25 of the resin molded product.
In FIG. 3 a, the temporary transfer layer 12 is transferred to the sealing portion 25 only in the portion in contact with the sealing portion 25. That is, the temporary transfer layer 12 is partially cut and divided into a portion 12 a transferred to the sealing portion 25 and a portion 12 b remaining on the release film 10. In this case, the subsequent step of removing the temporary transfer layer 12 becomes easy.
In FIG. 3B, the entire temporary transfer layer 12 is transferred to the sealing portion 25.
In FIG. 3 c, a part of the temporary transfer layer 12 that is in contact with the sealing portion 25 is transferred to the sealing portion 25. That is, similar to FIG. 3 a, the temporary transfer layer 12 is divided into a portion 12 a transferred to the sealing portion 25 and a portion 12 b remaining on the release film 10.

Finally, a process of removing the temporary transfer layer 12 transferred to the resin molded product will be described.
Examples of the method for removing the temporary transfer layer 12 transferred to the sealing portion 25 of the resin molded product include methods such as polishing, blasting, and cleaning. For example, in the method of manufacturing a semiconductor package, the sealing portion 25
After molding, there is a step of polishing the surface of the sealing portion in order to reduce the thickness, but this polishing step may also serve as the removal step of the temporary transfer layer 12. In that case, existing equipment can be used, the number of steps can be the same as in the conventional method, complication of the manufacturing steps can be avoided, and the product cost can be suppressed.

[Example 1]
A PVA layer (temporary transfer layer 12) was provided by coating polyvinyl alcohol (PVA) on one surface of a 50 μm SPS-based polymer simultaneous biaxially stretched film (support layer 11) to obtain a release film 10 in FIG. The thickness of the PVA layer after the coating was dried was 10 μm. This is Example 1.
[Example 2]
A linear low-density polyethylene (LLDPE) is extrusion-laminated on one surface of a 50 μm SPS-based polymer simultaneous biaxially stretched film (support layer 11) to provide a 15 μm LLDPE layer (temporary transfer layer 12). A film 10 was obtained. This is Example 2.
[Example 3]
Linear low density polyethylene (LL) is provided on one side of the PET simultaneous biaxially stretched film (support layer 11).
DPE) was extrusion laminated to provide a 15 μm LLDPE layer (temporary transfer layer 12) to obtain a release film 10 of FIG. This is Example 3.
Table 1 shows the configurations of Examples 1 to 3.

Using the release film 10 of Examples 1 to 3, as shown in FIGS. 4A and 4B, the resin 20 was press-molded by the mold 30 including the upper mold 31 and the lower mold 32. Specifically, the substrate 15, the resin 20, and the release film 10 are sequentially arranged from the bottom between the upper and lower molds, and the upper mold 31
The resin molding surface 30a of is heated to the molding temperature, the upper molding die 31 is brought close to the lower molding die 32,
The resin 20 was molded into the sealing portion 25 of the resin molded product. Reference numeral 16 is a spacer for controlling the approach of the upper molding die 31 and the lower molding die 32. Epoxy resin flakes (prepolymer) were used as the resin 20. The thickness of the substrate 15 is 1 mm, the molding temperature is 180° C.,
Molding (hot pressing) time was 3 minutes.
In each of the examples, the temporary transfer layer 12 of the release film 10 was transferred to the sealing portion 25 by separating the release film 10 from the sealing portion 25 after molding the sealing portion 25.
In each of the examples, the transferred temporary transfer layer 12 could be removed from the sealing portion 25 by polishing or blasting. When the release film 10 of Example 1 was used, the temporary transfer layer 12 could be removed by washing with water.

10 Release film 11 Support layer 12 Temporary transfer layer 12a Transferred portion 12b Remaining portion 15 Substrate 16 Spacer 20 Resin 25 Sealing portion 30 Mold 30a Resin molding surface 31 Upper molding die 31a Recess 31b Suction port 32 Lower molding Mold 32a Suction port

Claims (6)

A release film for use in resin molding in a semiconductor package sealing process ,
A support layer having a biaxially oriented SPS-based polymer film and having releasability,
Provided on one side of said support layer, and a that Do a polyolefin resin temporary transfer layer,
At least a part of the temporary transfer layer is transferred to a resin molded product, and removed from the resin molded product in a polishing step of the resin molded product.
Release film. The thickness of the temporary transfer layer is 35 μm or less (excluding those having a thickness of less than 10 μm) ,
The release film according to claim 1. The temporary transfer layer is made of linear low-density polyethylene ,
The release film according to claim 1 or 2. The temporary transfer layer is a layer laminated by extrusion lamination on the one surface of the support layer,
The release film according to claim 1. A step of preparing the release film according to any one of claims 1 to 4 ,
A step of arranging the substrate, the resin, and the release film in this order, and molding while compressing the resin with upper and lower molds;
And transferring the sealing portion of the resin molded article at least part of said temporary transfer layer of the release film,
Was removed by polishing the temporary transfer layer transferred to the sealing portion, and a step of polishing the sealing portion surface,
Manufacturing method of semiconductor package . The step of removing the temporary transfer layer transferred to the sealing portion by polishing is a step of polishing the surface of the sealing portion for thinning the semiconductor package.
The method for manufacturing a semiconductor package according to claim 5.

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