JP7685352B2 - Sheet for processing workpiece and method for manufacturing processed workpiece - Google Patents

Description

The present invention relates to a workpiece processing sheet that can be used to process workpieces such as semiconductor elements, and a method for manufacturing the processed workpieces.

The manufacturing method of a semiconductor device generally includes a dicing process in which a semiconductor wafer is diced on a dicing sheet to obtain multiple semiconductor chips, and a pick-up process in which the obtained semiconductor chips are individually picked up from the dicing sheet.

In the above pick-up process, in order to make it easier to pick up the semiconductor chips, the semiconductor chips may be pushed up individually from the side of the dicing sheet opposite the side on which the semiconductor chips are stacked. In particular, in the above pick-up process, in order to prevent collisions between the semiconductor chips during pick-up and to make pick-up easier, the dicing sheet is usually expanded to separate the semiconductor chips from each other. For this reason, the dicing sheet is required to have excellent flexibility that allows for good expansion.

Patent Document 1 discloses a dicing tape that is based on an expanding process, in which the ratio of the second tensile stress generated at a strain value of 20% in a tensile test performed on a dicing tape test piece having a width of 20 mm, an initial chuck distance of 100 mm, 23°C, and a tensile speed of 10 mm/min to the first tensile stress generated at a strain value of 20% in a tensile test performed on a dicing tape test piece having a width of 20 mm, an initial chuck distance of 100 mm, 23°C, and a tensile speed of 10 mm/min is 1.4 or more.

JP 2019-16634 A

Patent Document 1 also discloses that the thermal shrinkage rate in a heat treatment test conducted under conditions of a heating temperature of 100°C and a heat treatment time of 60 seconds is 2 to 30%. This is because the portion of the dicing tape outside the semiconductor chip holding area is heated and sufficiently shrunk before the expanded state is released. This makes it possible to prevent the spacing between the semiconductor chips with die bond film on the dicing tape from narrowing after the expanded state is released.

Depending on the type of semiconductor device, the semiconductor chips (workpieces) separated on the dicing sheet may be transferred to a transfer sheet, and the transfer sheet may then be expanded. In some cases, the semiconductor chips may be subjected to the desired processing, such as heating or inspection, while the transfer sheet is in an expanded state, and the semiconductor chips may be picked up from the transfer sheet after the expansion is released. In this case, it is desirable for the transfer sheet to be restored to its original shape. The dicing tape described in Patent Document 1 does not take such uses into consideration at all.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a workpiece processing sheet that has excellent restorability after being released from expansion, and a method for manufacturing a processed workpiece using the workpiece processing sheet.

Ｎ：試験力（Ｎ）
Ｌ：伸度（％）
Ｎ_Ｌ＋１：Ｌ＋1のときの試験力（Ｎ）
Ｌ_＋１：次項の伸度（％） In order to achieve the above object, first, the present invention provides a work processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate, characterized in that when a tensile test is performed on the substrate at 23°C and a tensile speed of 200 mm/min, the hysteresis loss calculated by the following formula (I) is 0.53 J or less (Invention 1).

N: Test force (N)
L: Elongation (%)
N _L+1 : Test force at L+1 (N)
L ₊₁ : Elongation (%)

The workpiece processing sheet according to the above invention (Invention 1) has the above physical properties and therefore has excellent restoring properties after being released from expansion. In other words, after the workpiece processing sheet holding the workpiece is expanded and then released from the expansion, the workpiece processing sheet is restored to its original shape and size.

In the above invention (Invention 1), it is preferable that the breaking elongation of the substrate in a tensile test at 23°C is 500% or more and 1500% or less (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the surface roughness (Ra) of the surface of the substrate opposite the pressure-sensitive adhesive layer is 0.01 μm or more and 5.00 μm or less (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the substrate contains a thermoplastic elastomer (Invention 4).

In the above inventions (Inventions 1 to 4), the substrate may be composed of a single layer containing a thermoplastic elastomer (Invention 5), or may be composed of multiple layers including a layer containing a thermoplastic elastomer (Invention 6).

In the above inventions (Inventions 1 to 6), it is preferable that the adhesive layer is expanded while holding multiple workpieces, and the workpieces are picked up from the adhesive layer after being released from the expanded state (Invention 7).

Secondly, the present invention provides a method for manufacturing a processed workpiece using the workpiece processing sheet (Inventions 1 to 7), comprising an expansion step of expanding the workpiece processing sheet while holding a plurality of workpieces in the adhesive layer, a processing step of performing a predetermined processing on the workpieces while the workpiece processing sheet is in the expanded state, a release step of releasing the workpiece processing sheet from the expanded state, and a pick-up step of picking up the processed workpieces from the adhesive layer of the workpiece processing sheet in the released state (Invention 8).

In the above invention (Invention 8), it is preferable to include a transfer step in which multiple workpieces are transferred to the adhesive layer of the workpiece processing sheet (Invention 9).

The workpiece processing sheet according to the present invention has excellent restoring properties after being released from expansion. Furthermore, according to the processed workpiece manufacturing method according to the present invention, the workpiece processing sheet has excellent restoring properties after being released from expansion, and therefore the workpiece is easy to handle after being released from expansion.

1 is a graph of a tensile curve showing hysteresis loss.

Ｎ：試験力（Ｎ）
Ｌ：伸度（％）
Ｎ_Ｌ＋１：Ｌ＋1のときの試験力（Ｎ）
Ｌ_＋１：次項の伸度（％） Hereinafter, an embodiment of the present invention will be described.
The work processing sheet according to one embodiment of the present invention includes a substrate and an adhesive layer laminated on one side of the substrate. When a tensile test is performed on the substrate at 23° C. and a tensile speed of 200 mm/min, the hysteresis loss calculated by the following formula (I) is 0.53 J or less.

N: Test force (N)
L: Elongation (%)
N _L+1 : Test force at L+1 (N)
L ₊₁ : Elongation (%)

The above hysteresis loss is obtained as the area enclosed by the load curve and unload curve in a graph of elongation (%)-normalized test force (N) when a tensile test is performed at 23°C so that the elongation of the substrate is 0%-100%-0%, and the test force at 100% elongation is normalized to 10 N. Specifically, it is obtained as the area of the shaded area enclosed by the load curve and unload curve in the graph of Figure 1. It is preferable that the above hysteresis loss is satisfied in both the MD direction (the flow direction during the manufacture of the substrate) and the CD direction (the direction perpendicular to the MD direction) of the substrate. Details of the above tensile test are as shown in the test example described later.

The workpiece processing sheet according to this embodiment has the above physical properties, and therefore has excellent restoring properties after being released from expansion. That is, after the workpiece processing sheet holding the workpiece is expanded and then the expansion is released, the workpiece processing sheet returns to its original shape and size. Therefore, even after the expansion is released, the holding position of the workpiece is accurately maintained, and the workpiece can be handled well. For example, with the workpiece processing sheet according to this embodiment in an expanded state, the desired processing of the workpiece on the workpiece processing sheet, such as heating or inspection, can be carried out well, and then after the expansion is released, the workpiece can be picked up well from the workpiece processing sheet.

The adhesive layer in the workpiece processing sheet is very soft compared to the substrate, so the tensile properties of the workpiece processing sheet are dominated by the tensile properties of the substrate. Therefore, in the workpiece processing sheet according to this embodiment, the tensile properties are determined by the hysteresis loss of the substrate as described above, which can be considered as the same as determining the workpiece processing sheet.

From the viewpoint of restorability after release from expansion, the hysteresis loss is 0.53 J or less, preferably 0.528 J or less, and particularly preferably 0.526 J or less. There is no particular limit to the lower limit of the hysteresis loss, and it is most preferably 0 J, but it is usually preferably 0 J or more, particularly preferably 0.15 J or more, and even more preferably 0.3 J or more.

In the work processing sheet according to this embodiment, the breaking elongation of the substrate in a tensile test at 23°C is preferably 500% or more, more preferably 540% or more, and particularly preferably 580% or more. The breaking elongation is preferably 1500% or less, more preferably 1400% or less, and particularly preferably 1300% or less. When the breaking elongation is within the above range, the work processing sheet can be expanded well in the expansion process, and the above-mentioned hysteresis loss tends to be easily satisfied. The above breaking elongation is preferably satisfied in both the MD and CD directions of the substrate.

In the work processing sheet according to this embodiment, the surface roughness (Ra) of the surface of the substrate opposite the adhesive layer is preferably 0.01 μm or more, more preferably 0.03 μm or more, and particularly preferably 0.05 μm or more. The surface roughness (Ra) is preferably 5.00 μm or less, more preferably 3.00 μm or less, and particularly preferably 2.00 μm or less. The "surface of the substrate opposite the adhesive layer" is the surface that comes into contact with a push-up tool when the push-up tool is used in the expansion process. The method for measuring the surface roughness (Ra) in this specification is as shown in the test example described later.

By having the surface roughness (Ra) within the above range, the workpiece processing sheet can be expanded well in the expansion process using a push-up jig or the like.

1. Structure of the work processing sheet (1) Substrate The material constituting the substrate of the work processing sheet according to this embodiment is not particularly limited as long as it satisfies the above-mentioned physical properties (particularly the physical properties determined by the tensile test). From the viewpoint of easily achieving the physical properties, it is preferable that the substrate in this embodiment contains a thermoplastic elastomer.

The substrate in this embodiment may be composed of a single layer or multiple layers. When the substrate in this embodiment is composed of a single layer, it is preferable that the substrate of the single layer contains a thermoplastic elastomer, and it is particularly preferable that the substrate has a thermoplastic elastomer as the main component (a component that accounts for more than 50% of the total). When the substrate in this embodiment is composed of multiple layers, it is preferable that at least one layer, preferably more than half the layers or layers with a thickness of more than half, and particularly preferably all layers contain a thermoplastic elastomer, and it is particularly preferable that the thermoplastic elastomer is the main component. This makes it easier for the substrate to satisfy the physical properties described above.

Examples of thermoplastic elastomers include urethane-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, styrene-based elastomers, acrylic-based elastomers, and amide-based elastomers. Among these, it is preferable to use urethane-based elastomers or styrene-based elastomers, as these are more easily able to achieve the above-mentioned physical properties.

A urethane-based elastomer is generally obtained by reacting a long-chain polyol, a diisocyanate, and a chain extender, and is composed of a soft segment having a structural unit derived from the long-chain polyol, and a hard segment having a polyurethane structure obtained by reacting a diisocyanate with a chain extender.

When urethane-based elastomers are classified according to the type of long-chain polyol used as the soft segment component, they can be divided into polyester-based polyurethane elastomers, polyether-based polyurethane elastomers, polycarbonate-based polyurethane elastomers, etc. Of these, it is preferable to use polyester-based polyurethane elastomers in the work processing sheet according to this embodiment, from the viewpoint of ease in achieving the above-mentioned physical properties.

Examples of the long-chain polyols include polyester polyols such as lactone-based polyester polyols and adipate-based polyester polyols; polyether polyols such as polypropylene (ethylene) polyols and polytetramethylene ether glycol; and polycarbonate polyols. Of these, it is preferable to use polyester polyols because they are easy to achieve the above-mentioned physical properties.

Examples of the above diisocyanates include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and hexamethylene diisocyanate. Of these, it is preferable to use hexamethylene diisocyanate because it is easy to achieve the above-mentioned physical properties.

The chain extender may be a low molecular weight polyhydric alcohol such as 1,4-butanediol or 1,6-hexanediol, or an aromatic diamine. Of these, it is preferable to use 1,6-hexanediol because it is easier to achieve the above-mentioned physical properties.

Examples of styrene-based elastomers include styrene-conjugated diene copolymers and styrene-olefin copolymers, among which styrene-conjugated diene copolymers are preferred. Specific examples of styrene-conjugated diene copolymers include unhydrogenated styrene-conjugated diene copolymers such as styrene-butadiene copolymer, styrene-butadiene-styrene copolymer (SBS), styrene-butadiene-butylene-styrene copolymer, styrene-isoprene copolymer, styrene-isoprene-styrene copolymer (SIS), and styrene-ethylene-isoprene-styrene copolymer; and hydrogenated styrene-conjugated diene copolymers such as styrene-ethylene/propylene-styrene copolymer (SEPS: hydrogenated styrene-isoprene-styrene copolymer) and styrene-ethylene-butylene-styrene copolymer (SEBS: hydrogenated styrene-butadiene copolymer). The styrene-based elastomer may be hydrogenated (hydrogenated) or unhydrogenated, but hydrogenated products are preferred. Among the above, hydrogenated styrene-conjugated diene copolymers are preferred from the viewpoint of the ease of achieving the aforementioned physical properties, and styrene-ethylene-butylene-styrene copolymers (SEBS) are particularly preferred.

When the substrate in this embodiment is composed of multiple layers, the materials constituting the layers other than the layer containing the thermoplastic elastomer are not particularly limited, but a material that does not inhibit the tensile properties of the layer containing the thermoplastic elastomer is preferred.

When the substrate in this embodiment is composed of multiple layers, it is preferably composed of 2 to 5 layers, particularly preferably composed of 3 to 4 layers, and more preferably composed of 3 layers. When the substrate is composed of two layers, it is preferable that both layers contain a thermoplastic elastomer. When the substrate is composed of three layers, it is preferable that two or more layers contain a thermoplastic elastomer, and particularly preferably that all three layers contain a thermoplastic elastomer. When there are multiple layers containing a thermoplastic elastomer in the substrate, the thermoplastic elastomers may be of the same type or different types. When the layers are of the same type, they may have the same composition or different compositions.

In order to improve adhesion with the adhesive layer, the surface of the substrate on which the adhesive layer is to be laminated may be subjected to a surface treatment such as an oxidation method or a roughening method, or a primer treatment. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment, and examples of the roughening method include sandblasting and thermal spraying treatment.

The substrate in this embodiment may contain various additives such as fillers, lubricants, colorants, flame retardants, plasticizers, antistatic agents, and fillers. In particular, the inclusion of a filler or lubricant may make it easier to meet the above-mentioned surface roughness (Ra).

The filler may be an inorganic filler or an organic filler. The inorganic filler may be spherical or amorphous. Among them, silica filler, especially amorphous silica filler, is preferably used.

Examples of lubricants include fatty acid lubricants, fatty acid amide lubricants, ester lubricants, polyethylene wax, liquid paraffin, etc., and one type may be used alone or two or more types may be used in combination.

In addition, when the adhesive layer in this embodiment contains a material that is cured by active energy rays, it is preferable that the substrate is transparent to active energy rays.

The method for producing the substrate in this embodiment is not particularly limited as long as it is possible to produce a substrate that achieves the above-mentioned physical properties. For example, the substrate can be produced by forming the above-mentioned materials into a sheet by melt extrusion methods such as the T-die method and round die method; calendaring method; or solution methods such as the dry method and wet method. In each production method, the surface roughness (Ra) of the obtained substrate can be adjusted by controlling the surface shape (roughness) of the member with which the formed sheet comes into contact, such as a cooling roll.

In this embodiment, the thickness of the substrate is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 25 μm or more. In this embodiment, the thickness of the substrate is preferably 500 μm or less, more preferably 300 μm or less, and particularly preferably 150 μm or less. By having the thickness of the substrate within the above range, the above-mentioned physical properties are easily satisfied, and excellent handling properties are also obtained.

(2) Adhesive Layer The adhesive constituting the adhesive layer in this embodiment is not particularly limited as long as it can exert the desired adhesive strength on the adherend (work). Examples of adhesives constituting the adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among these, it is preferable to use acrylic adhesives from the viewpoint of easily exerting the desired adhesive strength.

The adhesive constituting the adhesive layer in this embodiment may be an active energy ray curable adhesive or an active energy ray non-curable adhesive, and may be appropriately selected depending on the application. For example, when it is desired to greatly change the adhesive strength depending on the application, it is preferable to use an active energy ray curable adhesive. In this case, the adhesive layer is cured by irradiation with active energy rays, and the adhesive strength of the workpiece processing sheet to the adherend can be easily reduced. In particular, irradiation with active energy rays makes it possible to easily separate the processed workpiece from the workpiece processing sheet. If there is no need for the above, an active energy ray non-curable adhesive may be used.

The non-curable acrylic adhesive is preferably an adhesive obtained by crosslinking an adhesive composition containing a (meth)acrylic acid ester polymer and a crosslinking agent. In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the term "polymer" includes the concept of "copolymer."

The (meth)acrylic acid ester polymer preferably contains, as monomer units constituting the polymer, an alkyl (meth)acrylate ester and a reactive functional group-containing monomer. Preferred examples of the alkyl (meth)acrylate ester include alkyl (meth)acrylate esters having an alkyl group of 1 to 20 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Preferred examples of the reactive functional group-containing monomer include hydroxyl group-containing monomers, carboxy group-containing monomers, and amino group-containing monomers. These monomers may be used alone or in combination of two or more.

The crosslinking agent may be any that reacts with the reactive functional group of the (meth)acrylic acid ester polymer, and examples of such crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and amine-based crosslinking agents.

The thickness of the adhesive layer in this embodiment may be set appropriately depending on the application, but is usually preferably 1 to 100 μm, more preferably 5 to 50 μm, and even more preferably 8 to 20 μm. By having the thickness of the adhesive layer within the above range, the workpiece processing sheet according to this embodiment is more likely to exhibit the desired adhesiveness.

(3) Release sheet In the workpiece processing sheet according to this embodiment, a release sheet may be laminated on the side of the adhesive layer opposite the substrate (hereinafter sometimes referred to as the "adhesive side") in order to protect said side until it is attached to the workpiece.

The release sheet may have any configuration, and may be, for example, a plastic film that has been subjected to a release treatment using a release agent or the like. Specific examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. The release agent may be silicone-based, fluorine-based, or long-chain alkyl-based, and among these, silicone-based agents are preferred because they are inexpensive and provide stable performance.

There are no particular limitations on the thickness of the release sheet, and it may be, for example, 20 μm or more and 250 μm or less.

(4) Others In the workpiece processing sheet according to this embodiment, an adhesive layer may be laminated on the surface of the adhesive layer opposite to the substrate. In this case, the workpiece processing sheet according to this embodiment can be used, for example, as a dicing/die bonding sheet. In this sheet, a workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer, and the adhesive layer is diced together with the workpiece to obtain a chip on which the individualized adhesive layer is laminated. The individualized adhesive layer makes it possible for the chip to be easily fixed to the object on which the chip is mounted. As the material constituting the above-mentioned adhesive layer, it is preferable to use one containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, one containing a B-stage (semi-cured) thermosetting adhesive component, etc.

In addition, in the workpiece processing sheet according to this embodiment, a protective film forming layer may be laminated on the adhesive surface of the adhesive layer. In this case, the workpiece processing sheet according to this embodiment can be used, for example, as a sheet for forming a protective film and dicing. In such a sheet, a workpiece is attached to the surface of the protective film forming layer opposite to the adhesive layer, and the protective film forming layer is diced together with the workpiece to obtain a chip on which an individualized protective film forming layer is laminated. As the workpiece, it is preferable to use one having a circuit formed on one side, and in this case, the protective film forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. The individualized protective film forming layer can be cured at a predetermined timing to form a protective film having sufficient durability on the chip. The protective film forming layer is preferably made of an uncured curable adhesive.

2. Manufacturing method of the work processing sheet The manufacturing method of the work processing sheet according to the present embodiment is not particularly limited. For example, it is preferable to obtain the work processing sheet by forming an adhesive layer on a release sheet, and then laminating one side of a substrate on the side of the adhesive layer opposite to the release sheet.

The above-mentioned adhesive layer can be formed by a known method. For example, a coating liquid containing an adhesive composition for forming the adhesive layer and, if desired, a solvent or dispersion medium is prepared. Then, the coating liquid is applied to the releasable surface of the release sheet (hereinafter, sometimes referred to as the "release surface"). The resulting coating film is then dried to form the adhesive layer.

The coating of the coating liquid described above can be carried out by a known method, such as bar coating, knife coating, roll coating, blade coating, die coating, gravure coating, etc. The properties of the coating liquid are not particularly limited as long as it can be applied, and the liquid may contain the components for forming the adhesive layer as a solute or as a dispersoid. The release sheet may be peeled off as a processing material, or may protect the adhesive layer until it is applied to the adherend.

When the adhesive composition for forming the adhesive layer contains the above-mentioned crosslinking agent, it is preferable to advance the crosslinking reaction between the polymer component in the coating film and the crosslinking agent by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment, and form a crosslinked structure with the desired density in the adhesive layer. Furthermore, in order to advance the above-mentioned crosslinking reaction sufficiently, after laminating the adhesive layer and the substrate, curing may be performed, for example by leaving the adhesive layer to stand for several days in an environment of 23°C and a relative humidity of 50%.

3. Physical Properties of the Work Processing Sheet The work processing sheet according to this embodiment has a restoration rate of preferably 99.7% or more, more preferably 99.8% or more, particularly preferably 99.9% or more, and even more preferably 100% in a test example of the restoration evaluation described below. The work processing sheet according to this embodiment has the above-mentioned physical properties, and thus can achieve the excellent restoration rate as described above.

4. Method of using the workpiece processing sheet The workpiece processing sheet according to this embodiment can be suitably used to perform desired processing on multiple workpieces on the workpiece processing sheet when the workpiece processing sheet is in an expanded state. The processed workpieces can be picked up from the workpiece processing sheet after the expanded state is released, or from the workpiece processing sheet which has been further expanded thereafter. The workpiece processing sheet according to this embodiment has excellent restoring ability after being released from the expanded state, so that the holding position of the workpiece is accurately maintained, and the above-mentioned pick-up can be performed accurately.

The work is preferably singulated, and may be singulated on the work processing sheet by dicing or the like, or may be a work that has been singulated in a separate process and transferred to the work processing sheet. Types of singulated work include semiconductor elements, semiconductor chips, semiconductor packages, semiconductor components, glass components, etc., including LED elements, chip LEDs, etc. Examples of work before being singulated include semiconductor wafers and glass plates.

The work processing sheet is preferably expanded using a known expander having a push-up tool, but is not limited to this. This push-up tool contacts the surface of the base material of the work processing sheet opposite the adhesive layer, and pushes up the work processing sheet, thereby expanding the work processing sheet.

Examples of the desired processing include heat treatment, inspection, inspection under heat, etc., as well as deposition, sputtering, baking, etc. For example, in the case of inspection under heat, the workpiece processing sheet according to this embodiment can be sufficiently expanded, so that the distance between the workpieces can be relatively large, and thus the inspection of each workpiece can be carried out at the desired temperature.

The work processing sheet according to this embodiment can be used, for example, as a transfer sheet that also serves as an expand sheet and a pick-up sheet, and can also be used as a dicing sheet, a dicing/die bonding sheet, a sheet for forming a protective film, etc.

5. Processed Work Manufacturing Method By using the work processing sheet according to this embodiment, a processed work can be manufactured. The processed work manufacturing method according to one embodiment of the present invention includes an expansion step of expanding the work processing sheet while holding multiple workpieces with the adhesive layer, a processing step of performing a desired processing on the workpieces while the work processing sheet is in the expanded state, a release step of releasing the work processing sheet from the expanded state, and a pick-up step of picking up the processed workpieces from the adhesive layer of the work processing sheet in the released state. When holding multiple workpieces on the adhesive layer of the work processing sheet, a transfer step of transferring multiple workpieces to the adhesive layer may be included. In addition, when holding multiple workpieces on the adhesive layer of the work processing sheet, a dicing step of dicing the workpieces before being divided by the work processing sheet may be included.

The above-mentioned transfer process, dicing process, expansion process, release process and pick-up process can each be carried out by a known method. The specific processing in the processing process is not particularly limited, and for example, the processing described above can be carried out.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

For example, other layers may be provided on the side of the substrate opposite the adhesive layer, or between the substrate and the adhesive layer.

The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

Example 1
(1) Preparation of adhesive composition 80 parts by mass of 2-ethylhexyl acrylate (2EHA) and 20 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized by solution polymerization to obtain a (meth)acrylic acid ester polymer. The weight average molecular weight (Mw) of this (meth)acrylic acid ester polymer was measured by the method described below and was found to be 800,000.

100 parts by mass of the obtained (meth)acrylic acid ester polymer (based on solid content; the same applies below) was mixed with 5 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent in a solvent to obtain a coating solution of the adhesive composition.

(2) Formation of adhesive layer The coating solution of the adhesive composition obtained in the above step (1) was applied to the release-treated surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET381031", thickness: 38 μm) in which one side of a polyethylene terephthalate film was release-treated with a silicone-based release agent, and the resulting coating was dried for 1 minute at 100° C. This resulted in a laminate in which a 10 μm-thick adhesive layer was formed on the release surface of the release sheet.

(3) Preparation of substrate A polyester polyurethane elastomer (hardness (JIS-A): 90, density: 1.12 g/cm ³ ), which is a thermoplastic elastomer, was prepared as a raw material resin. The above thermoplastic elastomer (pellets) was fed to an extruder having a diameter of 50 mm of a single-layer inflation film-making device (manufactured by Tomii Machinery Co., Ltd., product name "IF1000-55S-TWRJ") and melt-kneaded. The pellets were then introduced into a single-layer die at a temperature of 205°C and extruded to obtain a substrate made of polyester polyurethane elastomer having a thickness of 30 μm.

(4) Preparation of work processing sheet One side of the substrate obtained in the above step (3) was bonded to the side of the adhesive layer of the laminate obtained in the above step (2) to obtain a work processing sheet. In the work processing sheet of Example 1, the tensile test described later was performed in the MD direction of the substrate.

The weight average molecular weight (Mw) mentioned above is a weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted into standard polystyrene.
<Measurement conditions>
Measuring device: Tosoh Corporation, HLC-8320
GPC columns (passed in the following order): TSK gel super H-H manufactured by Tosoh Corporation
TSK gel superHM-H
TSK gel superH2000
Measurement solvent: tetrahydrofuran Measurement temperature: 40°C

Example 2
(1) Preparation of Substrate As a raw material resin, a polyester-based polyurethane elastomer (hardness (JIS-A): 92, density: 1.24 g/cm ³ ) was prepared as a thermoplastic elastomer, and amorphous silica was prepared as a filler.

The above thermoplastic elastomer (pellets) and filler were fed into a 100 mm diameter extruder of a single-layer inflation film-making device (manufactured by Tomii Machinery Co., Ltd., product name "IF1000-55S-TWRJ") and melt-kneaded. The mixture was then guided to a single-layer die at a temperature of 205°C and extruded to obtain a substrate made of a polyester-based polyurethane elastomer (containing amorphous silica) with a thickness of 100 μm.

(2) Preparation of work processing sheet A work processing sheet was obtained by bonding one side of the substrate obtained in the above step (1) to the adhesive layer side of the laminate obtained in step (2) of Example 1. In addition, in the work processing sheet of Example 2, the tensile test described later was performed in the MD direction of the substrate.

Example 3
(1) Preparation of Substrate In this example, a substrate having a three-layer structure was prepared using the following three types of raw resin:
(a) Layer in contact with the pressure-sensitive adhesive layer (first layer)
Styrene-ethylene-butylene-styrene copolymer (SEBS) as a thermoplastic elastomer
(b) Middle layer (second layer)
Styrene-ethylene-butylene-styrene copolymer (SEBS) as a thermoplastic elastomer
(c) Layer on the opposite side to the pressure-sensitive adhesive layer (third layer)
Styrene-ethylene-butylene-styrene copolymer (SEBS) as a thermoplastic elastomer

The above resins (pellets) were put into the hopper of a single-screw extruder (Toshiba Machine Co., Ltd., product name "TEM-50", 50φmm, L/D=32), and the extruder temperatures were set as follows: C1: 210°C, C2: 230°C, C3: 230°C, C4: 230°C, C5: 230°C, and co-extruded from a 550mm wide T-die (temperature setting: 230°C, lip opening 0.3mm). The extruded molten resin was cooled and solidified by a winder equipped with a cooling roll (cooling roll: 700mm wide x φ350mm, roll temperature 30°C), and a substrate with a thickness of 145μm was obtained. In this substrate, the first layer had a thickness of 1μm, the second layer had a thickness of 138μm, and the third layer had a thickness of 6μm.

(2) Preparation of work processing sheet A work processing sheet was obtained by bonding the first layer side of the substrate obtained in the above step (1) with the adhesive layer side of the laminate obtained in step (2) of Example 1. In addition, in the work processing sheet of Example 3, the tensile test described later was performed in the CD direction of the substrate.

Example 4
The workpiece processing sheet of Example 3 is the same as the workpiece processing sheet of Example 3. However, in the workpiece processing sheet of Example 4, the tensile test described below was carried out in the MD direction of the substrate.

Example 5
Except for changing the type of cooling roll in the winding machine, the substrate and the workpiece processing sheet were prepared in the same manner as in Example 3. In addition, in the workpiece processing sheet of Example 5, the tensile test described later was performed in the CD direction of the substrate.

Example 6
The workpiece processing sheet of Example 6 is the same as the workpiece processing sheet of Example 5. However, in the workpiece processing sheet of Example 6, the tensile test described below was carried out in the MD direction of the substrate.

Example 7
(1) Preparation of substrate A polyester-based polyurethane elastomer (hardness (JIS-A): 88, density: 1.12 g/cm ³ ) was prepared as a thermoplastic elastomer as a raw resin. The above thermoplastic elastomer (pellets) was fed to an extruder having a diameter of 100 mm of a single-layer inflation film-making device (manufactured by Tomii Machinery Co., Ltd., product name "IF1000-55S-TWRJ") and melt-kneaded. The mixture was then introduced into a single-layer die at a temperature of 205°C and extruded to obtain a substrate made of polyester-based polyurethane elastomer having a thickness of 100 μm.

(2) Preparation of work processing sheet A work processing sheet was obtained by bonding the first layer side of the substrate obtained in the above step (1) with the adhesive layer side of the laminate obtained in step (2) of Example 1. In addition, in the work processing sheet of Example 7, the tensile test described later was performed in the MD direction of the substrate.

Example 8
A workpiece processing sheet was prepared in the same manner as in Example 7, except that the raw material resin of the substrate was changed to a thermoplastic elastomer, polyester-based polyurethane elastomer (hardness (JIS-A): 92, density: 1.24 g/cm ³ ). In addition, for the workpiece processing sheet of Example 8, the tensile test described later was performed in the MD direction of the substrate.

Example 9
A workpiece processing sheet was prepared in the same manner as in Example 7, except that the raw material resin of the substrate was changed to a thermoplastic elastomer, polyester-based polyurethane elastomer (hardness (ASTM D2240): 97, density: 1.22 g/cm ³ ). In addition, for the workpiece processing sheet of Example 9, the tensile test described later was performed in the MD direction of the substrate.

Comparative Example 1
(1) Preparation of Substrate In this example, a substrate having a three-layer structure was prepared using the following three types of raw resin:
(a) Layer in contact with the pressure-sensitive adhesive layer (first layer)
Styrene-ethylene-butylene-styrene copolymer (SEBS) as a thermoplastic elastomer
(b) Middle layer (second layer)
Styrene-ethylene-butylene-styrene copolymer (SEBS) as a thermoplastic elastomer
(c) Layer on the opposite side to the pressure-sensitive adhesive layer (third layer)
Polyethylene Resin

The above resins (pellets) were put into the hopper of a single-screw extruder (Toshiba Machine Co., Ltd., product name "TEM-50", 50φmm, L/D=32), and the extruder temperatures were set as follows: C1: 210°C, C2: 230°C, C3: 230°C, C4: 230°C, C5: 230°C, and co-extruded from a 550mm wide T-die (temperature setting: 230°C, lip opening 0.3mm). The extruded molten resin was cooled and solidified by a winder equipped with a cooling roll (cooling roll: 700mm wide x φ350mm, roll temperature 30°C), and a substrate with a thickness of 100μm was obtained. In this substrate, the thickness of the first layer was 2μm, the thickness of the second layer was 94μm, and the thickness of the third layer was 4μm.

(2) Preparation of work processing sheet A work processing sheet was obtained by bonding the first layer side of the substrate obtained in the above step (1) with the adhesive layer side of the laminate obtained in step (2) of Example 1. In addition, in the work processing sheet of Comparative Example 1, the tensile test described later was performed in the MD direction of the substrate.

Comparative Example 2
Except for changing the thickness of the second layer to 93 μm, the thickness of the third layer to 5 μm, and changing the type of cooling roll in the winder, a substrate and a workpiece processing sheet were prepared in the same manner as in Comparative Example 1. In addition, in the workpiece processing sheet of Comparative Example 2, the tensile test described later was performed in the MD direction of the substrate.

Comparative Example 3
Except for changing the thickness of the second layer to 91 μm, the thickness of the third layer to 7 μm, and changing the type of cooling roll in the winder, a substrate and a workpiece processing sheet were prepared in the same manner as in Comparative Example 1. In addition, in the workpiece processing sheet of Comparative Example 3, the tensile test described later was performed in the MD direction of the substrate.

Comparative Example 4
Except for changing the thickness of the second layer to 88 μm, the thickness of the third layer to 10 μm, and changing the type of cooling roll in the winder, a substrate and a workpiece processing sheet were prepared in the same manner as in Comparative Example 1. In addition, in the workpiece processing sheet of Comparative Example 4, the tensile test described later was performed in the MD direction of the substrate.

Comparative Example 5
(1) Preparation of a substrate A substrate was prepared by mixing 100 parts by mass (solid content equivalent; the same applies below) of polyvinyl chloride resin (manufactured by Taiyo Vinyl, product name "TH-1000", average polymerization degree: 1000), 10 parts by mass of terephthalic acid ester plasticizer A (di(2-ethylhexyl) terephthalate, manufactured by ADEKA, product name "ADEKA Cizer D-810", molecular weight: 391), 20 parts by mass of adipic acid polyester B1 (manufactured by ADEKA, product name "ADEKA Cizer PN-7160", weight average molecular weight: 800, plasticization efficiency value: 1.00) as an adipic acid ester plasticizer, and 5 parts by mass of adipic acid ester monomer C (manufactured by New Japan Chemical, product name "SANSO CIZER DINA", molecular weight 398), and phthalocyanine blue-based colorant (manufactured by Dainichiseika Chemicals, product name "DA A mixture consisting of 0.13 parts by mass of a quinacridone red colorant (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "DA P4121 Red"), 0.03 parts by mass of a quinacridone red colorant (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "DA P4121 Red"), and a small amount of a barium magnesium stabilizer was kneaded using a Banbury mixer at 180° C. The kneaded mixture was rolled with a calendar roll to obtain a substrate made of a polyvinyl chloride resin having a thickness of 80 μm.

(2) Preparation of workpiece processing sheet A workpiece processing sheet was obtained by bonding one side of the substrate obtained in the above step (1) to the adhesive layer side of the laminate obtained in step (2) of Example 1. In addition, in the workpiece processing sheet of Comparative Example 5, the tensile test described later was performed in the MD direction of the substrate.

[Test Example 1] (Measurement of surface roughness)
The surface roughness (Ra) of the surface of the substrate prepared in the examples and comparative examples on which the adhesive layer is not laminated was measured using an optical interference microscope (manufactured by Veeco, product name "surface profiler WYKO NT110") in accordance with JIS B601:2001. At this time, the measurement conditions were PSI, the magnification was 50 times, and the average value of five measurement points was taken as the surface roughness value. The results are shown in Table 1.

Ｎ：試験力（Ｎ）
Ｌ：伸度（％）
Ｎ_Ｌ＋１：Ｌ＋1のときの試験力（Ｎ）
Ｌ_＋１：次項の伸度（％） [Test Example 2] (Hysteresis Loss Measurement)
The substrates prepared in the examples and comparative examples were cut to a width of 15 mm x length of 150 mm, and these were used as test pieces. The test pieces were placed in a tensile/compression tester (manufactured by A&D Co., Ltd., product name "Tensilon") so that the stretchable portion of the test piece was 100 mm. Then, a tensile test was performed at a temperature of 23°C, a tensile speed of 200 mm/min, and the elongation was changed from 0% to 100% to 0%, and the test force was normalized to 10 N when the elongation was 100%. From the obtained graph, the hysteresis loss was calculated using the following formula (I). The results are shown in Table 1.

N: Test force (N)
L: Elongation (%)
N _L+1 : Test force at L+1 (N)
L ₊₁ : Elongation (%)

In addition, a tensile test was performed in the same manner as above, and the breaking elongation (%) was measured when the substrate broke. The results are shown in Table 1.

[Test Example 3] (Evaluation of restorability)
The workpiece processing sheets prepared in the examples and comparative examples were attached to a 6-inch ring frame of an expanding device (manufactured by JCM, product name "SE-100"), and a 2 cm square grid was drawn in the center of the workpiece processing sheet. Then, the 6-inch stage, which is a push-up jig, was pushed up at a push-up height of 34 mm and a push-up speed of 5 mm/s to expand the workpiece processing sheet, and this was maintained for 30 seconds. Thereafter, the push-up jig was returned to its original position to release the stress. The side length of the grid was measured 1 minute after the stress release, and the expansion rate (%) was calculated from the following formula. The measurements were performed in the MD and CD directions of the base material of the workpiece processing sheet, and the average value was taken as the expansion rate (%). The results are shown in Table 1.
Recovery rate (%)={1-(side length after stress release-side length before expansion)/side length before expansion}×100

Based on the above recovery rate (%), the recovery was evaluated according to the following criteria. The results are shown in Table 1.
A: The recovery rate was 99.7% or more.
×: The recovery rate was less than 99.7%.

As can be seen from Table 1, the work processing sheet produced in the embodiment had excellent restoring ability after being released from expansion.

The workpiece processing sheet of the present invention is suitable for use in applications in which, while the workpiece processing sheet is in an expanded state, multiple workpieces placed on the workpiece processing sheet are subjected to processing such as heating and inspection, and then the workpieces are picked up.

Claims (9)

A workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
When a tensile test is performed on the substrate at 23° C. and a tensile speed of 200 mm/min, the hysteresis loss calculated by the following formula (I) is 0.53 J or less,
The workpiece processing sheet is at least one of a transfer sheet that also serves as an expand sheet and a pick-up sheet, a dicing sheet, a dicing/die bonding sheet, and a sheet for forming a protective film.
A work processing sheet characterized by:

N: Test force (N)
L: Elongation (%)
N _L+1 : Test force at L+1 (N)
L ₊₁ : Elongation (%) A workpiece processing sheet comprising a substrate and an adhesive layer laminated on one side of the substrate,
When a tensile test is performed on the substrate at 23° C. and a tensile speed of 200 mm/min, the hysteresis loss calculated by the following formula (I) is 0.53 J or less,
The breaking elongation of the substrate in a tensile test at 23° C. is 500% or more and 1500% or less.
A work processing sheet characterized by:

N: Test force (N)
L: Elongation (%)
N _L+1 : Test force at L+1 (N)
L ₊₁ : Elongation (%) The workpiece processing sheet according to claim 1 or 2, characterized in that the surface roughness (Ra) of the substrate on the side opposite the adhesive layer is 0.01 μm or more and 5.00 μm or less. The workpiece processing sheet according to any one of claims 1 to 3, characterized in that the base material contains a thermoplastic elastomer. The work processing sheet according to any one of claims 1 to 4, characterized in that the substrate is composed of a single layer containing a thermoplastic elastomer. The workpiece processing sheet according to any one of claims 1 to 4, characterized in that the substrate is composed of multiple layers including a layer containing a thermoplastic elastomer. The workpiece processing sheet according to any one of claims 1 to 6, characterized in that it is used in an application in which a plurality of workpieces are expanded while held by the adhesive layer, and the workpieces are picked up from the adhesive layer after being released from the expanded state. A method for producing a processed workpiece using the workpiece processing sheet according to any one of claims 1 to 7, comprising the steps of:
an expanding step of expanding the workpiece processing sheet while holding a plurality of workpieces by the adhesive layer;
a processing step of performing a predetermined processing on the workpiece with the workpiece processing sheet in an expanded state;
a releasing step of releasing the work processing sheet from the expanded state;
A method for manufacturing a processed workpiece, comprising a pick-up process for picking up the processed workpiece from the adhesive layer of the workpiece processing sheet in the released state. The method for manufacturing a processed workpiece according to claim 8, further comprising a transfer step for transferring a plurality of workpieces onto the adhesive layer of the workpiece processing sheet.