Method for manufacturing support sheets and workpieces

Abstract

To provide a support sheet which includes a base material and an energy ray curable adhesive layer, and in which the adhesive layer is formed on a matte surface of the base material, and the matte surface of the base material is fully embedded with the adhesive layer, the support sheet with a workpiece or workpiece processed product stuck thereon allowing, even when being heated, the workpiece processed product to be picked up normally from the support sheet.SOLUTION: A support sheet 1 includes a base material 11 and an adhesive layer 12 formed on one face 11a of the base material. The one face 11a is a matte surface. The adhesive layer 12 contains an energy ray curable compound and is energy ray curable, the energy ray curable compound having a viscosity at 23°C of 350 mPa s or less. When the support sheet 1 is stuck on a mirror surface of a silicon mirror wafer by the adhesive layer 12, and the adhesive layer 12 is heated at 130°C to be energy ray-cured, an adhesive force (X1) between the energy ray cured product and the silicon mirror wafer is 400 mN / 25 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a support sheet and a method for manufacturing a workpiece. [Background technology]

[0002] A support sheet is used when processing workpieces such as wafers to manufacture processed products such as chips. A typical support sheet comprises a base material and an adhesive layer provided on one surface of the base material. The adhesive layer in the support sheet is, for example, attached to the workpiece to be processed, and the support sheet fixes the workpiece in place during processing. If the processing is dicing, the support sheet functions as a dicing sheet. The resulting processed product is finally pulled away from the support sheet and picked up for use in its intended application. In this case, if the adhesive layer is energy-ray curable, curing the adhesive layer with energy rays reduces the adhesive force between the cured product and the processed product, making it easier to pick up the processed product.

[0003] On the surface of the adhesive layer opposite the substrate side, a protective film-forming film may be provided to form a protective film on the workpiece, thereby constituting a protective film-forming composite sheet. The protective film-forming film in the protective film-forming composite sheet is, for example, attached to the workpiece to be processed, and the protective film-forming composite sheet fixes the workpiece during processing and forms a protective film on the workpiece or workpiece processed product. The resulting workpiece processed product is finally pulled away from the support sheet with the protective film attached, picked up, and used for its intended purpose. Similarly, if the adhesive layer is energy-ray curable, energy-ray curing of the adhesive layer facilitates the pickup of the workpiece processed product with the protective film attached.

[0004] On the other hand, the support sheet may be heated while the workpiece or workpiece is attached to it. This heating may be done, for example, to remove foreign matter such as low molecular weight resin components adhering to the surface of the workpiece. It may also be done to wash away and remove fine foreign matter that has been generated during processing such as dicing of the workpiece and is adhering to the surface of the workpiece, and then to dry the workpiece. These heating processes are usually carried out with an upper limit of around 135°C. However, if the heat resistance of the support sheet is insufficient, heating the support sheet with the workpiece or workpiece attached to it at such a temperature may ultimately make it impossible to pick up the workpiece from the support sheet.

[0005] A heat-resistant support sheet suitable for heating has been disclosed, comprising a base material and an adhesive layer, wherein the Young's modulus of the base material at 23°C and the storage modulus E' of the base material at 120°C after heating at 120°C for 4 hours are both specified within a specific range (see Patent Document 1). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-119592 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, in the substrate used to construct the support sheet, at least one of its surfaces may have a relatively large degree of unevenness and be rough. Such surfaces have a relatively low gloss and appear to be matte-finished, and are sometimes referred to as "matte surfaces." In a support sheet in which an adhesive layer is provided on the matte surface of the substrate, for example, in the parts of the matte surface of the substrate corresponding to the valleys of the unevenness, it may be difficult to fill them with the adhesive layer, resulting in voids.

[0008] As described above, when a gap occurs between the substrate and the adhesive layer, the light transmittance may decrease when light is shone from outside the substrate side of the support sheet through the substrate to the adhesive layer side. In that case, for example, when a workpiece is processed to produce a workpiece, when the workpiece on the support sheet is observed and inspected through the support sheet, the workpiece cannot be observed properly, resulting in a decrease in inspection accuracy. Furthermore, if the adhesive layer is energy ray curable, when energy rays are shone onto the adhesive layer through the substrate, the irradiation may not be performed properly, resulting in a problem where the adhesive layer cannot be cured properly. In contrast, the support sheet disclosed in Patent Document 1 does not aim to solve these problems.

[0009] The present invention provides a support sheet comprising a base material and an adhesive layer, wherein the adhesive layer is energy ray curable, is provided on the matte surface of the base material, and the matte surface of the base material is sufficiently embedded with the adhesive layer, thereby enabling normal pickup of the workpiece from the support sheet even when the support sheet with a workpiece or workpiece attached is heated. [Means for solving the problem]

[0010] To solve the above problems, the present invention adopts the following configuration. [1] A support sheet comprising a base material and an adhesive layer provided on one surface of the base material, wherein the one surface is a matte surface, the adhesive layer contains an energy ray curable compound and is energy ray curable, the viscosity of the energy ray curable compound at 23°C is 350 mPa·s or less, the support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, the adhesive layer after attachment is heated at 130°C, the adhesive layer after heating is energy ray cured, and the adhesive force (X1) between the energy ray cured product of the adhesive layer and the silicon mirror wafer is measured, wherein the adhesive force (X1) is 400 mN / 25 mm or less. [2] The support sheet according to [1], wherein the adhesive layer further contains an energy-ray curable acrylic resin. [3] The support sheet according to [1] or [2], wherein the support sheet is attached to the surface of a stainless steel plate by the adhesive layer, the adhesive layer is heated to 130°C after attachment, and the adhesive force (Y2) between the heated adhesive layer and the stainless steel plate is measured, and the adhesive force (Y2) is 13,000 mN / 25 mm or more. [4] The support sheet according to any one of [1] to [3], wherein the support sheet is attached to the surface of a stainless steel plate by the adhesive layer, the adhesive layer after attachment is heated at 130°C, the adhesive layer after heating is cured by energy rays, and the adhesive force (Y1) between the energy-ray cured product of the adhesive layer and the stainless steel plate is measured and the adhesive force (Y1) is 300 mN / 25 mm or more.

[0011] [5] The support sheet according to any one of [1] to [4], wherein the support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, the adhesive layer is heated at 130°C after attachment, and the adhesive force (X2) between the heated adhesive layer and the silicon mirror wafer is measured, and the adhesive force (X2) is 13,000 mN / 25 mm or more. [6] The support sheet according to any one of items [1] to [5], wherein the average value of the light transmittance of the support sheet in the wavelength range of 400 to 800 nm is 80% or more. [7]. A method for manufacturing a workpiece, the manufacturing method comprising: attaching the adhesive layer in the support sheet according to any one of [1] to [6] to the workpiece and the ring frame, thereby obtaining a workpiece with a support sheet comprising the workpiece and the support sheet provided on the workpiece, and fixing the workpiece with the support sheet to the ring frame in an attaching step; after the attaching step, heating the adhesive layer in the support sheet fixed to the ring frame in a heating step; after the attaching step, processing the workpiece in the workpiece with the support sheet fixed to the ring frame to produce the workpiece in a processing step; after the heating step and the processing step, curing the adhesive layer attached to the ring frame by energy beam curing in a curing step; and after the curing step, separating and picking up the workpiece from the cured product of the adhesive layer in a picking-up step, a method for manufacturing a workpiece.

Advantages of the Invention

[0012] According to the present invention, there is provided a support sheet comprising a base material and an adhesive layer, the adhesive layer being energy beam curable, provided on the matte surface of the base material, the matte surface of the base material being sufficiently embedded in the adhesive layer, and enabling normal picking up of the workpiece from the support sheet even when the support sheet with the workpiece or the workpiece attached thereto is heated.

Brief Description of the Drawings

[0013] [Figure 1] It is a cross-sectional view schematically showing an example of a support sheet according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view for schematically explaining an example of a method for manufacturing a workpiece with a protective film according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0014] ◇Support Sheet A support sheet according to an embodiment of the present invention includes a base material and an adhesive layer provided on one surface of the base material. The one surface is a matte surface, and the adhesive layer contains an energy ray curable compound (which may be referred to as "energy ray curable compound (α)" in this specification), and is energy ray curable. The viscosity of the energy ray curable compound at 23°C is 350 mPa·s or less. The support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, the adhesive layer after attachment is heated at 130°C, and the adhesive layer after heating is cured by energy rays. When measuring the adhesive force (X1) (which may be simply referred to as "adhesive force (X1)" in this specification) between the energy ray cured product of the adhesive layer and the silicon mirror wafer, the adhesive force (X1) is 400 mN / 25 mm or less.

[0015] The support sheet of this embodiment can be used, for example, in the manufacture of workpieces as described later. The support sheet of this embodiment can be laminated with a protective film forming film, for example, to form a composite sheet for forming a protective film as described later.

[0016] In the support sheet of this embodiment, since the viscosity of the energy ray curable compound at 23°C is 350 mPa·s or less, it is possible to suppress the occurrence of voids between the matte surface of the base material and the adhesive layer, and the embedding property of the matte surface of the base material by the adhesive layer is high. Thus, because the embedding property of the matte surface of the base material by the adhesive layer is high, the average value of the light transmittance in the visible light region of the support sheet becomes high. Therefore, when inspecting the presence or absence of damage such as cracks and chips, so-called chipping, in the workpiece through the support sheet while the workpiece obtained by processing the workpiece using the support sheet is held on the support sheet, the inspection accuracy is high. Examples of the light transmittance in the visible light region include the light transmittance in the wavelength range of 400 to 800 nm (which may be referred to as "light transmittance (400 - 800 nm)" in this specification). Furthermore, because the adhesive layer on the matte surface of the substrate has high embedding properties, when irradiating the adhesive layer with energy rays through the substrate, the adhesive layer can be properly irradiated and thus cured properly.

[0017] In the support sheet of this embodiment, the adhesive strength (X1) is 400 mN / 25 mm or less, so that even after the support sheet to which the workpiece or workpiece processed object is attached is heated to a high temperature, the workpiece processed object can be made from the workpiece on the support sheet, the adhesive layer in the support sheet is cured to form a cured support sheet, and then the workpiece processed object can be picked up normally from the cured support sheet, resulting in high pick-upability. Examples of heating at this time include heating to remove foreign matter such as low molecular weight resin components adhering to the surface of the workpiece. Another example of heating at this time is heating to wash and remove fine foreign matter that is generated during processing such as dicing of the workpiece and adheres to the surface of the workpiece with water, and then to dry the workpiece processed object. An upper limit of the heating temperature during these heating processes is approximately 135°C.

[0018] In this specification, a support sheet after the adhesive layer has hardened may be referred to as a "hardened support sheet" in order to distinguish it from a support sheet before the adhesive layer has hardened.

[0019] In this specification, "room temperature" means a temperature that is neither cooled nor heated, i.e., a normal temperature, such as 18-28°C.

[0020] In this embodiment, examples of workpieces include wafers and semiconductor device panels.

[0021] Examples of the aforementioned wafers include semiconductor wafers composed of elemental semiconductors such as silicon, germanium, and selenium, and compound semiconductors such as GaAs, GaP, InP, CdTe, ZnSe, and SiC; and insulating wafers composed of insulators such as sapphire and glass. A circuit is formed on one side of a workpiece, such as these wafers. In this specification, the side of the workpiece on which the circuit is formed is referred to as the "circuit side." The side of the workpiece opposite to the circuit side is referred to as the "back side." A wafer is divided into chips by means of dicing or other methods. In this specification, as with the wafer, the side of the chip on which the circuit is formed is referred to as the "circuit side," and the side of the chip opposite the circuit side is referred to as the "back side." It is preferable that the circuit surface of the workpiece is provided with protruding electrodes such as bumps and pillars. It is preferable that the protruding electrodes are made of solder.

[0022] The aforementioned semiconductor device panel is handled during the manufacturing process of a semiconductor device. A specific example of such a panel is a semiconductor device in which one or more electronic components are sealed with a sealing resin, and multiple such semiconductor devices are arranged planarly within a circular, rectangular, or other shaped area.

[0023] In this embodiment, the workpiece is obtained by processing a workpiece. For example, if the workpiece is a wafer, the workpiece is a chip, and if the workpiece is a semiconductor wafer, the workpiece is a semiconductor chip.

[0024] In this specification, "energy beam" means an electromagnetic wave or charged particle beam that has an energy quantum. Examples of energy beams include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be irradiated, for example, by using high-pressure mercury lamps, fusion lamps, xenon lamps, black lights, or LED lamps as ultraviolet light sources. Electron beams can be irradiated using those generated by electron accelerators, etc. In this specification, "energy ray curable" means the property of hardening when irradiated with energy rays, and "non-energy ray curable" means the property of not hardening even when irradiated with energy rays. In this specification, "non-curable" means the property of not curing by any means, such as heating or irradiation with energy rays.

[0025] Figure 1 is a schematic cross-sectional view showing an example of a support sheet according to one embodiment of the present invention. Note that, for convenience in order to make the features of the present invention easier to understand, the figures used in the following description may show enlarged versions of key parts, and the dimensional ratios of each component may not be the same as in reality.

[0026] The support sheet 1 shown herein comprises a base material 11 and an adhesive layer 12 provided on one surface 11a of the base material 11. The support sheet 1 further comprises a release film 13 provided on the surface 12a of the adhesive layer 12 opposite to the base material 11 side. One side 11a of the base material 11 is a matte surface. The adhesive layer 12 contains an energy ray-curable compound (α) and is energy ray-curable. The adhesive strength (X1) measured using the support sheet 1 is 400 mN / 25 mm or less.

[0027] The support sheet of this embodiment is not limited to the one shown in Figure 1, and some components of the one shown in Figure 1 may be modified, deleted, or added, as long as the effects of the present invention are not impaired. For example, the support sheet 1 shown in Figure 1 includes a release film 13, but in the support sheet of this embodiment, the release film can be of any configuration, and the support sheet of this embodiment does not need to include a release film. For example, the support sheet 1 shown in Figure 1 comprises a base material 11, an adhesive layer 12, and a release film 13. However, the support sheet of this embodiment may also comprise other layers that do not correspond to the base material, adhesive layer, or release film. The other layers can be arbitrarily selected according to the purpose and are not particularly limited. However, in the support sheet of this embodiment, it is preferable that the base material and the adhesive layer are in direct contact with each other, and that the adhesive layer and the release film are in direct contact with each other.

[0028] Next, we will describe the details of each layer that makes up the support sheet of this embodiment.

[0029] <<Adhesive layer, adhesive composition (I)>> The adhesive layer is in the form of a sheet or film, contains the energy-ray curable compound (α), and is energy-ray curable. The physical properties of the adhesive layer can be adjusted before and after curing.

[0030] The adhesive layer may consist of one layer (single layer) or of two or more layers. If it consists of multiple layers, these layers may be identical or different, and there are no particular limitations on the combination of these layers.

[0031] In this specification, not only in the case of adhesive layers, "multiple layers may be identical or different from one another" means "all layers may be identical, all layers may be different, or only some layers may be identical," and further, "multiple layers are different from one another" means "at least one of the constituent materials and thickness of each layer is different from the other."

[0032] The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 60 μm, even more preferably 5 to 30 μm, and particularly preferably 8 to 25 μm. Having the adhesive layer thickness within this range improves the embedding ability of the adhesive layer on the matte surface of the substrate, and improves the aforementioned pick-up ability of the workpiece from the cured support sheet. Here, "thickness of the adhesive layer" refers to the total thickness of the adhesive layer. For example, the thickness of an adhesive layer consisting of multiple layers refers to the total thickness of all the layers that make up the adhesive layer.

[0033] In this specification, unless otherwise specified, "thickness" refers to the average of the thicknesses measured at five randomly selected locations on the object, not just in the case of an adhesive layer, and can be obtained using a constant-pressure thickness measuring instrument in accordance with JIS K7130.

[0034] The adhesive layer can be formed using an adhesive composition (I) containing an energy-ray curable compound (α). For example, the adhesive composition (I) can be applied to the surface to which the adhesive layer is to be formed, and dried as necessary to form the adhesive layer in the desired area. The ratio of the content of components that do not vaporize at room temperature in the adhesive composition (I) is usually the same as the ratio of the content of the same components in the adhesive layer.

[0035] In the adhesive layer, the ratio of the total content of one or more of the following components in the adhesive layer to the total mass of the adhesive layer shall not exceed 100% by mass. Similarly, in adhesive composition (I), the ratio of the total content of one or more of the following components in adhesive composition (I) to the total mass of adhesive composition (I) shall not exceed 100% by mass.

[0036] The adhesive composition (I) may be applied by known methods, such as using various coaters including an air knife coater, blade coater, bar coater, gravure coater, roll coater, roll knife coater, curtain coater, die coater, knife coater, screen coater, Meyer bar coater, and kiss coater.

[0037] The drying conditions for the adhesive composition (I) are not particularly limited. However, if the adhesive composition (I) contains a solvent as described later, it is preferable to heat dry it. In particular, the adhesive composition (I) containing a solvent is preferably heat dried at a temperature of 70 to 130°C for 10 seconds to 5 minutes.

[0038] When providing an adhesive layer on a substrate, for example, the adhesive composition (I) may be applied to the substrate and dried as necessary. Alternatively, for example, the adhesive composition (I) may be applied to a release film and dried as necessary to form an adhesive layer on the release film, and the exposed surface of this adhesive layer may be bonded to one surface of the substrate (more specifically, the matte surface) to laminate the adhesive layer on the substrate. In this case, the release film may be removed at either the manufacturing or use stage of the support sheet.

[0039] <Energy ray curable compound (α)> The energy-ray curable compound (α) is not particularly limited as long as its viscosity at 23°C is 350 mPa·s or less and it is energy-ray curable. The viscosity of the energy-curable compound (α) at ​​23°C may be, for example, 320 mPa·s or less, 220 mPa·s or less, 120 mPa·s or less, or 60 mPa·s or less. The lower the viscosity, the better the embedding ability of the adhesive layer on the mat surface of the substrate. The lower limit of the viscosity of the energy ray-curable compound (α) at ​​23°C is not particularly limited. For example, energy ray-curable compounds (α) with a viscosity of 5 mPa·s or higher are more readily available. The viscosity of the energy-curable compound (α) at ​​23°C may be, for example, 5 to 350 mPa·s, 5 to 320 mPa·s, 5 to 220 mPa·s, 5 to 120 mPa·s, and 5 to 60 mPa·s or less. However, these are just examples of the aforementioned viscosities.

[0040] The viscosity of the energy-curable compound (α) at ​​23°C can be measured, for example, using a single-cylinder type B (Brookfeed type) rotational viscometer.

[0041] Examples of energy-ray curable compounds (α) include monomers or oligomers having energy-ray polymerizable unsaturated groups that can be cured by irradiation with energy rays. Each molecule of the energy-ray curable compound (α) has one or more of the energy-ray polymerizable unsaturated groups, and may have three or more, but it is preferable to have one or two. Examples of energy-ray polymerizable unsaturated groups include the (meth)acryloyl group.

[0042] In this specification, "(meth)acryloyl group" is a concept that encompasses both "acryloyl group" and "methacryloyl group." The same applies to terms similar to "(meth)acryloyl group." For example, "(meth)acrylic acid" is a concept that encompasses both "acrylic acid" and "methacrylic acid," and "(meth)acrylate" is a concept that encompasses both "acrylate" and "methacrylate."

[0043] The energy-ray curable compound (α) is preferably a (meth)acrylic acid ester which may have substituents. Examples of substituted (meth)acrylic acid esters include compounds in which one or more carbon atoms in an alcohol-derived hydrocarbon group (a hydrocarbon group bonded to an oxygen atom that does not constitute a carbonyl group in an oxycarbonyl group (-OC(=O)-)) are substituted with substituents together with the hydrogen atoms bonded to these carbon atoms (for example, in units of -CH2-, =CH-). However, two adjacent carbon atoms are not substituted with substituents.

[0044] The hydrocarbon group in the (meth)acrylic acid ester, which is the energy-curable compound (α), may be linear, branched, or cyclic, and if cyclic, it may be monocyclic or polycyclic. The hydrocarbon group may have both a linear structure (either a linear structure or a branched structure, or both) and a cyclic structure.

[0045] The hydrocarbon group may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the aliphatic hydrocarbon group may be either a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. In this specification, a hydrocarbon group having only an aliphatic group and no aromatic cyclic group is an aliphatic hydrocarbon group, and a hydrocarbon group having both an aliphatic group and an aromatic cyclic group, or having only an aromatic cyclic group, is an aromatic hydrocarbon group.

[0046] The hydrocarbon group is preferably a cyclic structure, that is, a cyclic hydrocarbon group, or a hydrocarbon group having both a chain structure and a cyclic structure.

[0047] The hydrocarbon group is preferably an alkyl group, an alkylene group, or an aralkyl group (arylalkyl group).

[0048] The substituent may be an atomic group having a structure in which multiple atoms are bonded together, or it may be a single atom. Preferred substituents include, for example, an oxygen atom (-O-).

[0049] When the hydrocarbon group has the substituents, the number of substituents is adjusted as appropriate depending on the type of hydrocarbon group, but is usually preferably 1 to 4, and more preferably 1 to 3.

[0050] The number of carbon atoms in the hydrocarbon group is preferably 3 to 20, and may be any of 3 to 16, 3 to 12, and 3 to 8, or any of 4 to 20, 9 to 20, and 13 to 20, or any of 4 to 16 and 9 to 14. However, these are just examples of the number of carbon atoms. Here, "number of carbon atoms in the hydrocarbon group" means the number of carbon atoms in the hydrocarbon group before substitution with the substituent, if the hydrocarbon group has the substituent. For example, if the hydrocarbon group has only an oxygen atom (-O-) as a substituent, the number of carbon atoms in the hydrocarbon group means the number of carbon atoms in the hydrocarbon group when this oxygen atom is replaced with the pre-substituted group such as a methylene group (-CH2-).

[0051] The hydrocarbon group is preferably a hydrocarbon group having a cyclic structure and which may have an oxygen atom as a substituent; more preferably a hydrocarbon group having both a chain-like structure and a cyclic structure and which may have an oxygen atom as a substituent; even more preferably an aliphatic hydrocarbon group or an aromatic hydrocarbon group which may have an oxygen atom as a substituent; it is an aromatic hydrocarbon group having both an aliphatic group having an oxygen atom as a substituent and an aromatic cyclic group without a substituent (in this specification, the energy ray curable compound (α) in this case may be referred to as "energy ray curable compound (α1)"), or an aliphatic hydrocarbon group having both a cyclic structure without a substituent and a chain-like structure without a substituent (in this specification, the energy ray curable compound (α) in this case may be referred to as "energy ray curable compound (α2)"), or an aliphatic hydrocarbon group having both a cyclic structure having an oxygen atom as a substituent and a chain-like structure without a substituent (in this specification, the energy ray curable compound (α) in this case may be referred to as "energy ray curable compound (α3)"). By using such an energy-ray curable compound (α), the embedding ability of the adhesive layer on the matte surface of the substrate is further improved.

[0052] An example of the energy ray curable compound (α1) is energy ray curable compound (α)-1, which will be described later in the examples. An example of the aforementioned energy ray curable compound (α2) is energy ray curable compound (α)-2, which will be described later in the examples. An example of the aforementioned energy ray curable compound (α3) is energy ray curable compound (α)-3, which will be described later in the examples.

[0053] The molecular weight of the energy-ray-curable compound (α) is not particularly limited, but is preferably 500 or less. By using such an energy-ray-curable compound (α), the embedding ability of the adhesive layer on the matte surface of the substrate is further improved.

[0054] The molecular weight of the energy-ray-curable compound (α) is preferably 100 to 500, more preferably 200 to 400, and may be, for example, 200 to 310 and 200 to 280, or 250 to 400 and 310 to 400, or 250 to 310. Having a molecular weight below the upper limit further enhances the embedding ability of the adhesive layer on the matte surface of the substrate. Having a molecular weight above the lower limit further stabilizes the structure of the adhesive layer. However, these are just examples of molecular weights for the energy-ray-curable compound (α). Energy-ray curable compound (α1), energy-ray curable compound (α2), and energy-ray curable compound (α3) having any of the molecular weights shown herein are particularly preferred energy-ray curable compound (α).

[0055] The energy-ray curable compound (α) is a (meth)acrylic acid ester which may have a structure in which one or more carbon atoms in the hydrocarbon group derived from the alcohol in the (meth)acrylic acid ester are substituted with substituents together with the hydrogen atoms bonded to these carbon atoms, and it is preferable that the hydrocarbon group has a cyclic structure and the molecular weight is 500 or less. Such energy ray curable compound (α) is preferably one in which the hydrocarbon group is an alkyl group, an alkylene group, or an aralkyl group, and the substituent is an oxygen atom. It is preferably one of the energy ray curable compound (α1), the energy ray curable compound (α2), or the energy ray curable compound (α3), and is preferably one with a molecular weight within any of the further limited numerical ranges described above. It is more preferably one that satisfies one or more of these four conditions simultaneously.

[0056] The energy ray curable compound (α) contained in the adhesive layer and adhesive composition (I) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0057] In the adhesive composition (I), the ratio of the energy ray curable compound (α) to the total content of all components other than the solvent is preferably 5% by mass or more, and may be 10% by mass or more, or 14% by mass or more. On the other hand, the ratio is 100% by mass or less. This statement is equivalent to saying that the ratio of the content of the energy ray curable compound (α) to the total mass of the adhesive layer is preferably 5% by mass or more, and may be 10% by mass or more, or 14% by mass or more, and that the ratio is 100% by mass or less. This is based on the fact that, in the process of removing the solvent from a solvent-containing resin composition to form a resin film, the amount of components other than the solvent usually does not change, and the ratio of the contents of non-solvent components is the same in the resin composition and the resin film. Therefore, in this specification, not only in the case of an adhesive layer, but also thereafter, the content of non-solvent components will only be described in the resin film obtained by removing the solvent from the resin composition.

[0058] <Energy-ray curable acrylic resin (Ia)> Preferably, the adhesive layer and adhesive composition (I) further contain an energy-ray curable acrylic resin (also referred to herein as "energy-ray curable acrylic resin (Ia)"). The adhesive layer containing the energy-ray curable compound (α) and the energy-ray curable acrylic resin (Ia) makes it easier to adjust both the embedding ability of the mat surface of the substrate and the adhesive strength (X1).

[0059] Examples of the energy-ray curable acrylic resin (Ia) include resins having a structure in which an unsaturated group is introduced into the side chain of a non-energy-ray curable acrylic resin.

[0060] [Non-energy ray curable acrylic resin] Examples of the non-energy ray curable acrylic resin include acrylic polymers having structural units derived from alkyl (meth)acrylate esters and structural units derived from functional group-containing monomers.

[0061] Examples of the (meth)acrylate alkyl ester include those in which the alkyl group constituting the alkyl ester has 1 to 20 carbon atoms. The alkyl group constituting the alkyl ester may be linear, branched, or cyclic, but it is preferably linear or branched.

[0062] Among the alkyl (meth)acrylate esters mentioned above, those in which the alkyl group is linear or branched include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate Examples include n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate (lauryl methacrylate), tridecyl methacrylate, tetradecyl methacrylate (myristyl methacrylate), pentadecyl methacrylate, hexadecyl methacrylate (palmityl methacrylate), heptadecyl methacrylate, octadecyl methacrylate (stearyl methacrylate), nonadecyl methacrylate, and eicosyl methacrylate.

[0063] Among the alkyl (meth)acrylate esters mentioned above, those in which the alkyl group is cyclic include, for example, isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate.

[0064] Among the above, the alkyl (meth)acrylate ester is preferably 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, dodecyl acrylate (lauryl acrylate), or dodecyl methacrylate (lauryl methacrylate) in that it can reduce the adhesive strength (X1).

[0065] Examples of the functional group-containing monomers include those in which the functional group reacts with a crosslinking agent (described later) to serve as a starting point for crosslinking, or those in which the functional group reacts with a group in an unsaturated group-containing compound (described later) that can bond (react) with a non-energy ray curable acrylic resin, thereby enabling the introduction of an unsaturated group into the side chain of the acrylic polymer.

[0066] Examples of the functional group-containing monomers include hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like.

[0067] Examples of the hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; and non-(meth)acrylic unsaturated alcohols (unsaturated alcohols that do not have a (meth)acryloyl skeleton) such as vinyl alcohol and allyl alcohol. Among these, the hydroxyl group-containing monomer is preferably hydroxyalkyl methacrylate, and more preferably 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, or 2-hydroxybutyl methacrylate, in that it can reduce the adhesive force (X1).

[0068] Examples of the carboxyl group-containing monomers include ethylenically unsaturated monocarboxylic acids (monocarboxylic acids having an ethylenically unsaturated bond) such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids (dicarboxylic acids having an ethylenically unsaturated bond) such as fumaric acid, itaconic acid, maleic acid, and citraconic acid; anhydrides of the ethylenically unsaturated dicarboxylic acids; and carboxyalkyl esters of (meth)acrylic acid such as 2-carboxyethyl methacrylate.

[0069] Examples of the epoxy group-containing monomers include glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate.

[0070] The functional group-containing monomer is preferably a hydroxyl group-containing monomer.

[0071] Non-energy ray curable acrylic resins may have constituent units derived from other monomers that do not fall under either the constituent units derived from alkyl (meth)acrylate esters or the constituent units derived from the functional group-containing monomers.

[0072] The other monomers mentioned above are not particularly limited as long as they can be copolymerized with alkyl (meth)acrylate esters, etc. Examples of other monomers include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0073] The constituent units derived from alkyl (meth)acrylate, the constituent units derived from the functional group-containing monomer, and the constituent units derived from the other monomers in the non-energy ray-curable acrylic resin may each consist of only one type or two or more types, and if there are two or more types, their combinations and ratios can be arbitrarily selected.

[0074] In non-energy ray curable acrylic resins, the content of constituent units derived from alkyl (meth)acrylate is preferably 65 to 99% by mass relative to the total amount of constituent units.

[0075] In non-energy ray curable acrylic resins, the content of constituent units derived from functional group-containing monomers is preferably 1 to 35% by mass relative to the total amount of constituent units.

[0076] In a non-energy ray curable acrylic resin, the content of the constituent units derived from the other monomers is preferably 0 to 10% by mass relative to the total amount of constituent units.

[0077] Energy-ray curable acrylic resin (Ia) can be obtained, for example, by reacting the functional groups in a non-energy-ray curable acrylic resin with an unsaturated group-containing compound having an energy-ray polymerizable unsaturated group.

[0078] The aforementioned unsaturated group-containing compound is a compound that, in addition to the energy-ray polymerizable unsaturated group, has a group that can bond with the non-energy-ray curable acrylic resin by reacting with a functional group in the non-energy-ray curable acrylic resin. Examples of the energy-ray polymerizable unsaturated group include a (meth)acryloyl group, a vinyl group (ethenyl group), an allyl group (2-propenyl group), and the (meth)acryloyl group, which is preferred. Examples of groups that can bond with the functional groups in the non-energy ray curable acrylic resin include isocyanate groups and glycidyl groups that can bond with hydroxyl groups or amino groups, and hydroxyl groups and amino groups that can bond with carboxyl groups or epoxy groups.

[0079] Examples of the unsaturated group-containing compounds include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and glycidyl (meth)acrylate.

[0080] When obtaining an energy-ray curable acrylic resin (Ia) by reacting the functional groups in a non-energy-ray curable acrylic resin with an unsaturated group-containing compound having an energy-ray polymerizable unsaturated group, the total number of moles of unsaturated groups in the unsaturated group-containing compound relative to the total number of moles of functional groups in the non-energy-ray curable acrylic resin may be 0.6 times or more and 0.75 times or more, but it is preferably 0.8 times or more, more preferably 0.85 times or more, and even more preferably 0.9 times or more. The larger the total number of moles of unsaturated groups, the lower the adhesive force (X1) can be, and the higher the pickability of the workpiece from the cured support sheet tends to be. On the other hand, it is preferable that the total number of moles of unsaturated groups in the unsaturated group-containing compound is 1 or less compared to the total number of moles of functional groups in the non-energy ray curable acrylic resin.

[0081] The energy-curable acrylic resin (Ia) contained in the adhesive layer and adhesive composition (I) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0082] When the adhesive layer and adhesive composition (I) contain an energy-curable acrylic resin (Ia), the ratio of the energy-curable compound (α) content in the adhesive layer to the total mass of the adhesive layer is preferably 5 to 50% by mass, for example, it may be 5 to 35% by mass and 5 to 25% by mass, or 10 to 50% by mass and 14 to 50% by mass, or 10 to 35% by mass. When the ratio is above the lower limit, the embedding ability of the adhesive layer on the matte surface of the substrate is improved. When the ratio is below the upper limit, the pick-up ability, which allows the workpiece to be picked up from the support sheet without any problems, is improved.

[0083] When the adhesive layer and adhesive composition (I) contain an energy-curable acrylic resin (Ia), the ratio of the content of the energy-curable acrylic resin (Ia) in the adhesive layer to the total mass of the adhesive layer is preferably 50 to 95% by mass, for example, it may be 65 to 95% by mass and 75 to 95% by mass, or 50 to 90% by mass and 50 to 86% by mass, or 65 to 90% by mass. When the ratio is above the lower limit, the pickability is improved so that the workpiece can be picked up from the support sheet without any problems. When the ratio is below the upper limit, the embedding ability of the adhesive layer on the matte surface of the substrate is improved.

[0084] <Other ingredients> The adhesive layer and adhesive composition (I) may contain other components that do not fall under either the energy-ray curable compound (α) or the energy-ray curable acrylic resin (Ia), as long as they do not impair the effects of the present invention. Examples of the other components mentioned above include crosslinking agents (β), photopolymerization initiators (γ), and additives.

[0085] The other components contained in the adhesive layer and adhesive composition (I) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0086] [Crosslinking agent (β)] When preparing the energy-ray curable acrylic resin (Ia), if unreacted functional groups remain in the non-energy-ray curable acrylic resin with the unsaturated group-containing compound, the energy-ray curable acrylic resin (Ia) will have these functional groups. When using such an energy-ray curable acrylic resin (Ia), the adhesive layer and adhesive composition (I) may further contain a crosslinking agent (β). In the adhesive layer and adhesive composition (I) containing the crosslinking agent (β), the energy-ray curable acrylic resins (Ia) can be crosslinked with each other.

[0087] Examples of crosslinking agents (β) include isocyanate-based crosslinking agents (crosslinking agents having an isocyanate group) such as tolylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and adducts of these diisocyanates; epoxy-based crosslinking agents (crosslinking agents having a glycidyl group) such as ethylene glycol glycidyl ether; aziridine-based crosslinking agents (crosslinking agents having an aziridinyl group) such as hexa[1-(2-methyl)-aziridinyl]triphosphate triazine; metal chelate-based crosslinking agents (crosslinking agents having a metal chelate structure) such as aluminum chelate; and isocyanurate-based crosslinking agents (crosslinking agents having an isocyanuric acid skeleton). Among these, the crosslinking agent (β) is preferably an adduct of hexamethylene diisocyanate or an isocyanurate-modified hexamethylene diisocyanate, as this makes it easier to set the adhesive strength (X1) within the range described later.

[0088] The crosslinking agent (β) contained in the adhesive layer and adhesive composition (I) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0089] In the adhesive layer, the content of the crosslinking agent (β) is preferably 0.1 to 7 parts by mass per 100 parts by mass of the energy-ray curable acrylic resin (Ia), for example, it may be any of 0.1 to 5 parts by mass and 0.1 to 3 parts by mass, or any of 0.5 to 7 parts by mass, 1 to 7 parts by mass and 3 to 7 parts by mass, or any of 0.5 to 5 parts by mass and 1 to 3 parts by mass.

[0090] [Photopolymerization initiator (γ)] The adhesive layer and adhesive composition (I) may further contain a photopolymerization initiator (γ). The adhesive layer and adhesive composition (I) containing the photopolymerization initiator (γ) will undergo a sufficient curing reaction even when irradiated with relatively low-energy rays such as ultraviolet light.

[0091] Examples of the photopolymerization initiator (γ) include benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methyl benzoate, and benzoin dimethyl ketal; acetophenone compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one; and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl Examples include acylphosphine oxide compounds such as diphenylphosphine oxide; sulfide compounds such as benzylphenyl sulfide and tetramethylthiuram monosulfide; α-ketol compounds such as 1-hydroxycyclohexylphenyl ketone; azo compounds such as azobisisobutyronitrile; titanocene compounds such as titanocene; thioxanthone compounds such as thioxanthone; peroxide compounds; diketone compounds such as diacetyl; benzyl; dibenzyl; benzophenone; 2,4-diethylthioxanthone; 1,2-diphenylmethane; 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone; and quinone compounds such as 1-chloroanthraquinone and 2-chloroanthraquinone. As the photopolymerization initiator (γ), for example, photosensitizers such as amines can also be used. Among these, the photopolymerization initiator (γ) is preferably 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one, as it makes it easier to set the tackiness (X1) within the range described later.

[0092] The photopolymerization initiator (γ) contained in the adhesive layer and adhesive composition (I) may be one type or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0093] In the adhesive layer, the content of the photopolymerization initiator (γ) is preferably 0.5 to 5 parts by mass per 100 parts by mass of the total content of the energy-curable compound (α) and the energy-curable acrylic resin (Ia), regardless of whether the adhesive layer contains energy-curable acrylic resin (Ia). For example, it may be 1 to 4 parts by mass or 1.5 to 3.5 parts by mass.

[0094] [Additives] Examples of known additives include antistatic agents, antioxidants, plasticizers, fillers, rust inhibitors, colorants (pigments, dyes), sensitizers, tackifiers, reaction retarders, and crosslinking accelerators (catalysts). The reaction retarder is, for example, a component that suppresses the unintended crosslinking reaction that occurs in the adhesive composition (I) during storage due to the action of a catalyst mixed in the adhesive composition (I). Examples of reaction retarders include those that form a chelate complex by chelation with the catalyst, and more specifically, components that have two or more carbonyl groups (-C(=O)-) in one molecule.

[0095] The adhesive layer and adhesive composition (I) may contain only one type of additive, or two or more types, and if there are two or more types, their combination and ratio can be arbitrarily selected.

[0096] The content of the additives in the adhesive composition (I) is not particularly limited and may be appropriately selected depending on the type of additive.

[0097] [solvent] The adhesive composition (I) may contain a solvent. The presence of a solvent in the adhesive composition (I) improves its applicability to the surface to be coated.

[0098] The solvent is preferably an organic solvent, and examples of such organic solvents include ketones such as methyl ethyl ketone and acetone; esters (carboxylic acid esters) such as ethyl acetate; ethers such as tetrahydrofuran and dioxane; aliphatic hydrocarbons such as cyclohexane and n-hexane; aromatic hydrocarbons such as toluene and xylene; and alcohols such as 1-propanol and 2-propanol.

[0099] The adhesive composition (I) may contain only one solvent or two or more solvents, and if there are two or more solvents, their combination and ratio can be arbitrarily selected.

[0100] The solvent content of the adhesive composition (I) is not particularly limited and may be adjusted as appropriate.

[0101] <An embodiment of the adhesive layer> Examples of preferred adhesive layers and adhesive compositions (I) include those containing an energy-ray curable compound (α), an energy-ray curable acrylic resin (Ia), a crosslinking agent (β), and a photopolymerization initiator (γ).

[0102] <Method for producing adhesive composition (I)> The adhesive composition (I) is obtained by blending an energy-ray curable compound (α) with other components that constitute the adhesive composition (I), such as an energy-ray curable acrylic resin (Ia) if necessary. There are no particular restrictions on the order in which each component is added during formulation, and two or more components may be added simultaneously. The method of mixing each component during formulation is not particularly limited; it can be appropriately selected from known methods such as mixing by rotating a stirring bar or impeller, mixing using a mixer, or mixing by applying ultrasonic waves. The temperature and time during the addition and mixing of each component are not particularly limited as long as the components do not deteriorate, and can be adjusted as appropriate, but a temperature of 15 to 30°C is preferred.

[0103] <<Base material>> The substrate is in the form of a sheet or film, and its constituent materials include, for example, various resins. The aforementioned resins include, for example, polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE); polyolefins other than polyethylene such as polypropylene, polybutene, polybutadiene, polymethylpentene, and norbornene resin; ethylene-based copolymers such as ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, and ethylene-norbornene copolymer (polymers obtained using ethylene as a monomer); and vinyl chloride-based resins such as polyvinyl chloride and vinyl chloride copolymer (obtained using vinyl chloride as a monomer). Examples of materials include: modified resins; polystyrene; polycycloolefins; polyesters such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalenedicarboxylate, and all aromatic polyesters having aromatic cyclic groups as all constituent units; copolymers of two or more of the above polyesters; poly(meth)acrylic acid esters; polyurethanes; polyurethane acrylates; polyimides; polyamides; polycarbonates; fluororesins; polyacetals; modified polyphenylene oxides; polyphenylene sulfides; polysulfones; polyether ketones, etc. Furthermore, the resin may also include, for example, a polymer alloy such as a mixture of the polyester and other resins. In the polymer alloy of polyester and other resins, it is preferable that the amount of the resin other than polyester is relatively small. Furthermore, examples of the resin include crosslinked resins obtained by crosslinking one or more of the resins exemplified so far; and modified resins such as ionomers using one or more of the resins exemplified so far.

[0104] Among the above, polypropylene or polybutylene terephthalate is preferred as the resin that constitutes the base material, in terms of providing higher heat resistance (around 135°C) and flexibility of the base material.

[0105] The resin constituting the base material may consist of only one type, or two or more types. If there are two or more types, their combination and ratio can be arbitrarily selected.

[0106] In addition to the main constituent materials such as the aforementioned resin, the base material may also contain various known additives such as fillers, colorants, antioxidants, organic lubricants, catalysts, and plasticizers.

[0107] In the aforementioned support sheet, since the adhesive layer is energy ray curable, the substrate is preferably one that transmits energy rays and is transparent.

[0108] In the substrate, at least one surface may be a matte surface, both surfaces may be matte surfaces, or one surface may be a matte surface and the other surface may be a glossy surface with a low degree of unevenness. In the support sheet, an adhesive layer is provided on the matte surface of the base material. When both sides of the base material are matte surfaces, it is preferable that the adhesive layer be provided on the matte surface with the greater surface roughness (Ra).

[0109] The matte surface of a substrate is a surface with a roughness above a certain value and has low gloss, making it clearly identifiable by its appearance. Substrates with at least one matte surface are commercially available and can also be manufactured by known methods.

[0110] The surface roughness (Ra) of the matte surface of the substrate is preferably 0.05 μm or more, and may be, for example, 0.1 μm or more, 0.4 μm or more, or 0.7 μm or more. When the surface roughness is above the lower limit, the effect of the present invention, which is that the adhesive layer on the matte surface of the substrate has high embedding properties, is more significantly obtained. In addition, blocking of the substrates when they are stored stacked is further suppressed. There is no particular upper limit to the surface roughness (Ra) of the matte surface of the substrate. For example, in order to prevent the surface from becoming excessively uneven, the surface roughness is preferably 2 μm or less. The surface roughness (Ra) of the matte surface of the substrate may be, for example, 0.05 to 2 μm, 0.1 to 2 μm, 0.4 to 2 μm, and 0.7 to 2 μm. However, these are just examples of surface roughness.

[0111] In this specification, "surface roughness (Ra)" is not limited to the matte surface of the substrate, but refers to the so-called arithmetic mean roughness determined in accordance with JIS B0601:2001.

[0112] The surface roughness (Ra) of the glossy surface of the substrate is preferably less than 0.05 μm, and may be, for example, 0.04 μm or less. Having the surface roughness within this range results in a higher average light transmittance of the support sheet described later in the 400-800 nm wavelength range. The lower limit of the surface roughness (Ra) of the glossy surface of the substrate is not particularly limited. For example, in terms of suppressing blocking of the substrates when they are stored stacked, the surface roughness is preferably 0.01 μm or more. The surface roughness (Ra) of the glossy surface of the substrate may be, for example, 0.01 μm or more and less than 0.05 μm, or 0.01 to 0.04 μm. However, these are just examples of surface roughness.

[0113] The surface roughness (Ra) of both sides of the substrate can be adjusted, for example, by the molding conditions of the substrate or the surface treatment conditions. Examples of surface treatments include sandblasting and solvent treatment to create unevenness, and polishing to smooth the surface.

[0114] The substrate may be subjected to oxidation treatments such as corona discharge treatment, electron beam irradiation treatment, plasma treatment, ozone / ultraviolet irradiation treatment, flame treatment, chromic acid treatment, or hot air treatment; lipophilic treatment; hydrophilic treatment; etc., on its surface to adjust its adhesion to the adhesive layer provided thereon. The surface of the substrate may also be primed.

[0115] The base material may consist of one layer (single layer) or of two or more layers. If it consists of multiple layers, these layers may be identical or different, and there are no particular limitations on the combination of these layers.

[0116] The thickness of the substrate is preferably 50 to 300 μm, and more preferably 60 to 100 μm. Having the substrate thickness within this range improves the heat resistance (e.g., around 135°C), flexibility, and suitability for attachment to the workpiece of the support sheet. Here, "substrate thickness" refers to the total thickness of the substrate. For example, the thickness of a substrate consisting of multiple layers refers to the total thickness of all the layers that make up the substrate.

[0117] The substrate can be manufactured by known methods. For example, a substrate containing a resin can be manufactured by molding a resin composition containing the resin.

[0118] <<Release film>> The aforementioned release film may be one of known types. More specifically, a release film may be one in which one or both sides of the release film substrate are release surfaces. The release film substrate is preferably a polyethylene terephthalate film. The aforementioned release surface can be formed by peeling the surface of the substrate for the release film with a known release agent. The thickness of the release film may be, for example, 2 to 300 μm, and is preferably 20 to 100 μm.

[0119] Next, the physical properties of the support sheet (adhesive layer) will be described.

[0120] <Adhesive strength (X1)> The adhesive strength (X1) is 400 mN / 25 mm or less, preferably 340 mN / 25 mm or less, and may be, for example, 280 mN / 25 mm or less, 220 mN / 25 mm or less, or 180 mN / 25 mm or less. The smaller the adhesive strength (X1), the higher the pickability, which allows the workpiece to be picked up from the cured support sheet without any problems. The lower limit of the adhesive strength (X1) is not particularly limited. For example, an adhesive layer with an adhesive strength (X1) of 30 mN / 25 mm or more can be formed more easily. The adhesive strength (X1) may be, for example, 30-400 mN / 25 mm, 30-340 mN / 25 mm, 30-280 mN / 25 mm, 30-220 mN / 25 mm, or 30-180 mN / 25 mm or less. However, these are just examples of adhesive strength (X1).

[0121] The adhesive strength (X1) can be measured, for example, by the method shown below. Specifically, first, a test piece with a width of 25 mm is cut from the support sheet. Next, the test piece (support sheet) is attached to the mirror surface of the silicon mirror wafer using the adhesive layer within it to produce a silicon mirror wafer with the test piece attached. This attachment is preferably performed at room temperature, with an attachment speed of 290-310 mm / min and an attachment pressure of 0.3 MPa, using a laminating roller. Next, the silicon mirror wafer with the test specimen attached is heated at 130°C for 2 hours. Next, the silicon mirror wafer with the test specimen attached was cooled by air cooling until its temperature reached 23°C, and then subjected to an illuminance of 230 mW / cm². 2 , light intensity 200mJ / cm 2 Under these conditions, the adhesive layer in the silicon mirror wafer with the test specimen attached, after cooling, is cured by irradiating it with energy rays through the substrate. Next, at room temperature, the test specimen is peeled from the silicon mirror wafer at a peeling speed of 300 mm / min. At this time, the test specimen is peeled in its longitudinal direction so that the side of the silicon mirror wafer to which the test specimen was attached and the side of the test specimen to which the silicon mirror wafer was attached form a 180° angle, a so-called 180° peeling procedure. The load (peeling force) at this 180° peeling is then measured, and the measurement length is set to 50 mm. The measurement values ​​for the first 5 mm and the last 5 mm are excluded from the valid values. The average of these measured values ​​is then adopted as the adhesive strength (X1) (mN / 25 mm). In this embodiment, such peeling force measurements may be performed on two or more test pieces (support sheets), and the average value of the multiple obtained measurements may be adopted as the adhesive force (X1).

[0122] <Adhesive strength (X2)> When the support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, and the adhesive layer is heated to 130°C after attachment, the adhesive force (X2) (which may be simply referred to as "adhesion force (X2)" in this specification) between the heated adhesive layer and the silicon mirror wafer is measured, it is preferable that the adhesive force (X2) is 13,000 mN / 25 mm or more. By using such a support sheet, even after the support sheet with the workpiece or workpiece attached is heated to a high temperature, peeling of the workpiece from the support sheet is suppressed even when a large force is applied to the workpiece due to processing of the workpiece or washing of the workpiece.

[0123] The adhesive strength (X2) is more preferably 14,000 mN / 25 mm or more, and may be, for example, 14,700 mN / 25 mm or more, 15,400 mN / 25 mm or more, or 16,100 mN / 25 mm or more. The greater the adhesive strength (X2), the greater the effect of suppressing peeling of the workpiece from the support sheet. The upper limit of the adhesive strength (X2) is not particularly limited. For example, an adhesive layer with an adhesive strength (X2) of 19,000 mN / 25 mm or less can be formed more easily. The adhesive strength (X2) may be, for example, 13,000 to 19,000 mN / 25 mm, 14,000 to 19,000 mN / 25 mm, 14,700 to 19,000 mN / 25 mm, 15,400 to 19,000 mN / 25 mm, and 16,100 to 19,000 mN / 25 mm. However, these are just examples of adhesive strength (X2).

[0124] The adhesive strength (X2) can be measured, for example, by the method shown below. Specifically, a silicon mirror wafer with a test piece attached is prepared using the same method as when measuring the adhesive strength (X1), heated at 130°C for 2 hours, and then cooled to 23°C by air cooling. Next, under conditions of 23°C, the test specimen is peeled off the cooled silicon mirror wafer at a peeling speed of 300 mm / min. At this time, the test specimen is peeled in its longitudinal direction, so as to be called 180° peeling, where the side of the silicon mirror wafer to which the test specimen was attached and the side of the test specimen to which the silicon mirror wafer was attached form a 180° angle. The load (peeling force) at this 180° peeling is then measured, and the measurement length is set to 50 mm. The measurement values ​​for the first 5 mm and the last 5 mm are excluded from the valid values. The average of these measured values ​​is then adopted as the adhesive force (X2) (mN / 25 mm). In this embodiment, such peeling force measurements may be performed on two or more test pieces (support sheets), and the average value of the multiple obtained measurements may be adopted as the adhesive force (X2).

[0125] <Adhesion (Y1)> The support sheet is attached to the surface of a stainless steel (SUS) plate using the adhesive layer, the adhesive layer is heated to 130°C after attachment, the heated adhesive layer is energy-ray cured, and the adhesive force (Y1) (sometimes simply referred to as "adhesion force (Y1)" in this specification) between the energy-ray cured adhesive layer and the stainless steel plate is measured, and it is preferable that the adhesive force (Y1) is 300 mN / 25 mm or more. In the method for manufacturing workpieces described later, a workpiece with a support sheet, comprising a workpiece and a support sheet provided on the workpiece, is fixed to a ring frame. In this state, a workpiece is manufactured from the workpiece, and the adhesive layer in the support sheet is cured by energy rays, becoming a cured support sheet. That is, after the energy ray curing of the adhesive layer, a cured support sheet workpiece, comprising a workpiece and a cured support sheet provided on the workpiece, or a cured support sheet workpiece, comprising a workpiece and a cured support sheet provided on the workpiece, can be obtained from the workpiece with a support sheet. In this way, after the energy ray curing of the adhesive layer, a laminate of the workpiece or workpiece and the cured support sheet is fixed to the ring frame. Furthermore, by using a support sheet with an adhesive strength (Y1) of 300 mN / 25 mm or more, even if the workpiece with the support sheet is further heated while fixed to the ring frame, and then energy rays are irradiated onto the contact portion of the support sheet (adhesive layer) with the ring frame, the peeling of the laminate of the workpiece or workpiece processed and the cured support sheet from the ring frame is suppressed.

[0126] The adhesive strength (Y1) is more preferably 400 mN / 25 mm or more, and may be, for example, 500 mN / 25 mm or more, or 600 mN / 25 mm or more. The greater the adhesive strength (Y1), the greater the effect of suppressing the peeling of the laminate of the workpiece or processed workpiece and the cured support sheet from the ring frame. The upper limit of the adhesive strength (Y1) is not particularly limited. For example, an adhesive layer with an adhesive strength (Y1) of 2000 mN / 25 mm or less can be formed more easily. The adhesive strength (Y1) may be, for example, 300-2000 mN / 25 mm, 400-2000 mN / 25 mm, 500-2000 mN / 25 mm, or 600-2000 mN / 25 mm. However, these are just examples of adhesive strength (Y1).

[0127] The adhesive strength (Y1) can be measured, for example, by the method shown below. Specifically, first, a test piece with a width of 25 mm is cut from the support sheet. Next, the test piece (support sheet) is attached to one side of a 1000 μm thick SUS plate using the adhesive layer within it to produce a SUS plate with the test piece attached. This attachment is preferably carried out at room temperature, with an attachment speed of 290 to 310 mm / min and an attachment pressure of 0.3 MPa, using a laminating roller. Next, the SUS plate with the test specimen attached is heated at 130°C for 2 hours. Next, the SUS plate with the test specimen attached was cooled by air cooling until its temperature reached 23°C, and then subjected to an illuminance of 230 mW / cm². 2 , light intensity 200mJ / cm 2 Under these conditions, the adhesive layer in the SUS plate with the test specimen attached, after cooling, is cured by irradiating it with energy rays through the substrate. Next, at room temperature, the test specimen is peeled from the SUS plate at a peeling speed of 300 mm / min. At this time, the test specimen is peeled in its longitudinal direction so that the side of the SUS plate to which the test specimen was attached and the side of the test specimen to which the SUS plate was attached form a 180° angle, a so-called 180° peeling procedure. The load (peeling force) at this 180° peeling is then measured, and the measurement length is set to 50 mm. The measurement values ​​at the first 5 mm and the measurement values ​​at the last 5 mm are excluded from the valid values. The average of these measurement values ​​is then adopted as the adhesive strength (Y1) (mN / 25 mm). In this embodiment, such peeling force measurements may be performed on two or more test pieces (support sheets), and the average value of the multiple obtained measurements may be adopted as the adhesive force (Y1).

[0128] <Adhesion (Y2)> When the support sheet is attached to the surface of a stainless steel (SUS) plate by the adhesive layer, and the adhesive layer is heated to 130°C after attachment, the adhesive force (Y2) between the heated adhesive layer and the stainless steel plate (sometimes simply referred to as "adhesion force (Y2)" in this specification) is measured, it is preferable that the adhesive force (Y2) is 13,000 mN / 25 mm or more. By using such a support sheet, in the method for manufacturing workpieces described later, even if the workpiece with the support sheet, or the workpiece with the support sheet comprising a workpiece and a support sheet provided on the workpiece, is further heated while fixed to the ring frame, peeling of the workpiece with the support sheet or the workpiece with the support sheet from the ring frame is suppressed.

[0129] The adhesive strength (Y2) is more preferably 14,000 mN / 25 mm or more, and may be, for example, 15,000 mN / 25 mm or more, 16,000 mN / 25 mm or more, or 17,000 mN / 25 mm or more. The greater the adhesive strength (Y2), the greater the effect of suppressing the peeling of the workpiece with the support sheet or the workpiece processed with the support sheet from the ring frame. The upper limit of the adhesive strength (Y2) is not particularly limited. For example, an adhesive layer with an adhesive strength (Y2) of 20,000 mN / 25 mm or less can be formed more easily. The adhesive strength (Y2) may be, for example, 13,000 to 20,000 mN / 25 mm, 14,000 to 20,000 mN / 25 mm, 15,000 to 20,000 mN / 25 mm, 16,000 to 20,000 mN / 25 mm, or 17,000 to 20,000 mN / 25 mm. However, these are just examples of adhesive strength (Y2).

[0130] The adhesive strength (Y2) can be measured, for example, by the method shown below. Specifically, a SUS plate with a test specimen is prepared using the same method as when measuring the adhesive strength (Y1), heated at 130°C for 2 hours, and then cooled to 23°C by air cooling. Next, under conditions of 23°C, the test specimen is peeled off the cooled SUS plate at a peeling speed of 300 mm / min. At this time, the test specimen is peeled in its longitudinal direction, so as to be called 180° peeling, where the side of the SUS plate to which the test specimen was attached and the side of the test specimen to which the SUS plate was attached form a 180° angle. The load (peeling force) at this 180° peeling is then measured, and the measurement length is set to 50 mm. The measurement values ​​for the first 5 mm and the last 5 mm are excluded from the valid values. The average of these measured values ​​is then adopted as the adhesive strength (Y2) (mN / 25 mm). In this embodiment, such peeling force measurements may be performed on two or more test pieces (support sheets), and the average value of the obtained multiple measurements may be adopted as the adhesive force (Y2).

[0131] <Adhesive strength (X0)> When the support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, and the silicon mirror wafer equipped with the support sheet is left standing for 30 minutes at a temperature of 23°C, and the adhesive force (X0) between the adhesive layer and the silicon mirror wafer (sometimes simply referred to as "adhesion force (X0)" in this specification) is measured, it is preferable that the adhesive force (X0) is 2000 mN / 25 mm or more. By using such a support sheet, even when a large force is applied to the workpiece or workpiece processed object while it is attached to the support sheet, such as during high-load processing of the workpiece (for example, high-speed dicing of a semiconductor wafer) or high-load water washing of the workpiece processed object (for example, high-pressure water washing of a semiconductor chip after dicing), peeling of the workpiece processed object from the support sheet is suppressed.

[0132] The adhesive strength (X0) is more preferably 2500 mN / 25 mm or more, and may be, for example, 3000 mN / 25 mm or more, 3500 mN / 25 mm or more, or 4000 mN / 25 mm or more. The greater the adhesive strength (X0), the greater the effect of suppressing peeling of the workpiece from the support sheet. The upper limit of the adhesive strength (X0) is not particularly limited. For example, in terms of balancing the adhesive strength (X0) with other physical properties of the adhesive layer, it is preferable that the adhesive strength (X0) is 6000 mN / 25 mm or less. The adhesive strength (X0) may be, for example, 2000-6000 mN / 25 mm, 2500-6000 mN / 25 mm, 3000-6000 mN / 25 mm, 3500-6000 mN / 25 mm, and 4000-6000 mN / 25 mm. However, these are just examples of adhesive strength (X0).

[0133] The adhesive strength (X0) can be measured, for example, by the method shown below. Specifically, first, a test piece with a width of 25 mm is cut from the support sheet. Next, the test piece (support sheet) is attached to the mirror surface of the silicon mirror wafer using the adhesive layer within it to produce a silicon mirror wafer with the test piece attached. This attachment is preferably performed at room temperature, with an attachment speed of 290-310 mm / min and an attachment pressure of 0.3 MPa, using a laminating roller. Next, the silicon mirror wafer with the test specimen attached is left to stand for 30 minutes under a temperature of 23°C. Next, at room temperature, the test specimen is peeled from the silicon mirror wafer at a peeling speed of 300 mm / min. At this time, the test specimen is peeled in its longitudinal direction so that the side of the silicon mirror wafer to which the test specimen was attached and the side of the test specimen to which the silicon mirror wafer was attached form a 180° angle, a so-called 180° peeling procedure. The load (peeling force) at this 180° peeling is then measured, and the measurement length is set to 50 mm. The measurement values ​​for the first 5 mm and the last 5 mm are excluded from the valid values. The average of these measured values ​​is then adopted as the adhesive strength (X0) (mN / 25 mm). In this embodiment, such peeling force measurements may be performed on two or more test pieces (support sheets), and the average value of the obtained multiple measurements may be adopted as the adhesive force (X0).

[0134] <Method for adjusting the adhesive strength of the adhesive layer> The various adhesive forces of the adhesive layer described above, namely the adhesive force between the energy-ray cured product of the adhesive layer after heating and the silicon mirror wafer (X1); the adhesive force between the adhesive layer after heating and the silicon mirror wafer (X2); the adhesive force between the energy-ray cured product of the adhesive layer after heating and the SUS plate (Y1); the adhesive force between the adhesive layer after heating and the SUS plate (Y2); and the adhesive force between the adhesive layer and the silicon mirror wafer (X0), can be adjusted by adjusting the type and content of the components contained in the adhesive layer.

[0135] For example, by incorporating an energy-curable acrylic resin (Ia) having constituent units derived from a functional group-containing monomer having a methacrylic group into the adhesive layer, the adhesive strength (X1) can be reduced. For example, by incorporating an energy-ray curable acrylic resin (Ia) with a relatively high glass transition temperature into the adhesive layer, the adhesive strength (X1) can be reduced. For example, when reacting a functional group (e.g., a hydroxyl group) in the acrylic polymer with a group in the unsaturated group-containing compound that can bond to the functional group (e.g., an isocyanate group in (meth)acryloyloxyethyl isocyanate), an energy-ray curable acrylic resin (Ia) can be prepared by setting the total number of moles of the groups in the unsaturated group-containing compound that can bond to the functional group to a relatively large amount (e.g., 0.75 times or more) relative to the total number of moles of the functional group in the acrylic polymer. By incorporating such an energy-ray curable acrylic resin (Ia) into the adhesive layer, the adhesive strength (X1) can be reduced.

[0136] For example, by including an energy-ray curable compound (α) in the adhesive layer, the adhesive strength (X2) can be increased compared to when the energy-ray curable compound (α) is not included. However, by adjusting the type of energy-ray curable compound (α), the adhesive strength (X2) can be further increased. For example, when using an energy-ray curable acrylic resin (Ia) obtained by reacting a functional group (e.g., a hydroxyl group) in the acrylic polymer with a group (e.g., an isocyanate group in (meth)acryloyloxyethyl isocyanate) in the unsaturated group-containing compound that can bond with the functional group, the adhesive strength (X2) can be increased by incorporating an energy-ray curable acrylic resin (Ia) in the adhesive layer that has fewer unreacted functional groups derived from the acrylic polymer (in other words, fewer functional groups that can react with the crosslinking agent (β)). For example, the adhesive strength (X2) can be increased by reducing the amount of crosslinking agent (β) in the adhesive layer.

[0137] For example, by incorporating an energy-curable acrylic resin (Ia) having constituent units derived from a functional group-containing monomer having a methacrylic group into the adhesive layer, the adhesive strength (Y1) can be increased. For example, by including an (meth)acrylic acid ester having an oxygen atom (-O-) as a substituent in the adhesive layer as an energy-ray curable compound (α), the adhesive strength (Y1) can be increased. For example, when using an energy-ray curable acrylic resin (Ia) obtained by reacting a functional group (e.g., a hydroxyl group) in the acrylic polymer with a group (e.g., an isocyanate group in (meth)acryloyloxyethyl isocyanate) that can bond to the functional group in the unsaturated group-containing compound, the adhesive strength (Y1) can be increased by including an energy-ray curable acrylic resin (Ia) in the adhesive layer that has fewer unreacted functional groups derived from the acrylic polymer (in other words, fewer functional groups that can react with the crosslinking agent (β)). For example, the adhesive strength (Y1) can be increased by reducing the amount of crosslinking agent (β) in the adhesive layer.

[0138] For example, by including an energy-ray curable compound (α) in the adhesive layer, the adhesive strength (Y2) can be increased compared to when the energy-ray curable compound (α) is not included. However, by adjusting the type of energy-ray curable compound (α), the adhesive strength (Y2) can be further increased. For example, when using an energy-ray curable acrylic resin (Ia) obtained by reacting a functional group (e.g., a hydroxyl group) in the acrylic polymer with a group (e.g., an isocyanate group in (meth)acryloyloxyethyl isocyanate) in the unsaturated group-containing compound that can bond with the functional group, the adhesive strength (Y2) can be increased by including an energy-ray curable acrylic resin (Ia) in the adhesive layer that has fewer unreacted functional groups derived from the acrylic polymer (in other words, fewer functional groups that can react with the crosslinking agent (β)). For example, the adhesive strength (Y2) can be increased by reducing the amount of crosslinking agent (β) in the adhesive layer.

[0139] For example, when using an energy-ray curable acrylic resin (Ia) obtained by reacting a functional group (e.g., a hydroxyl group) in the acrylic polymer with a group (e.g., an isocyanate group in (meth)acryloyloxyethyl isocyanate) in the unsaturated group-containing compound that can bond with the functional group, the adhesive strength (X0) can be increased by including an energy-ray curable acrylic resin (Ia) in the adhesive layer that has fewer unreacted functional groups derived from the acrylic polymer (in other words, fewer functional groups that can react with the crosslinking agent (β)). For example, the adhesive strength (X0) can be increased by reducing the amount of crosslinking agent (β) in the adhesive layer.

[0140] For example, in an adhesive layer containing an energy-curable compound (α), an energy-curable acrylic resin (Ia), and a crosslinking agent (β), using a crosslinking agent (β) with a chain structure that does not have a ring structure tends to increase the adhesive strength (Y2) and decrease the adhesive strength (X1) compared to using one with a ring structure. For example, in an adhesive layer containing an energy-curable compound (α), an energy-curable acrylic resin (Ia), and a crosslinking agent (β), using a crosslinking agent (β) that has urethane bonds, such as a diisocyanate trimethylolpropane adduct, tends to increase the adhesive strength (Y2) and decrease the adhesive strength (X1) compared to using one that does not have urethane bonds. For example, in an adhesive layer containing an energy-ray curable compound (α), an energy-ray curable acrylic resin (Ia), and a crosslinking agent (β), reducing the content of the energy-ray curable compound (α) can lower the adhesive strength (X1) compared to when the content is increased.

[0141] <Average light transmittance of the support sheet (400-800nm)> The average value of the light transmittance (400-800 nm) of the support sheet is preferably 80% or higher, and may be, for example, 82% or higher, or 84% or higher. When the average value of the light transmittance (400-800 nm) is above the lower limit, the inspection accuracy is improved when inspecting for damage such as cracks or chips (e.g., chipping) in the workpiece through the support sheet while the workpiece is held on the support sheet. The upper limit of the average value of the aforementioned light transmittance (400-800 nm) is not particularly limited. For example, a support sheet having an average value of 95% or less of the aforementioned light transmittance (400-800 nm) can be manufactured more easily. The average value of the aforementioned light transmittance (400-800 nm) may be, for example, 80-95%, 82-95%, or 84-95%. However, these are just examples of average values ​​for the aforementioned light transmittance (400-800 nm). However, in this specification, unless otherwise specified, the light transmittance of the support sheet refers not only to the light transmittance in the wavelength range of 400 to 800 nm, but also to the light transmittance of the support sheet without the release film.

[0142] The average light transmittance (400-800 nm) of the support sheet can be calculated, for example, by the method shown below. Specifically, light is shone onto the support sheet from the outside of the substrate side, and the light transmittance is measured by direct light reception without using an integrating sphere. The value of light transmittance T is measured for each 1 nm interval in the wavelength range of 400 to 800 nm, where n (nm) is the wavelength. n Measure the formula (where n is an integer between 400 and 800). Then, measure the T when n is between 400 and 800. n Add up all the values ​​and get the total T400-800 Calculate it. The obtained T 400-800 is divided by the measurement number of T n (that is, 800 - 400 + 1 = 401) (T 400-800 / 401), whereby the average value of the light transmittance (400 to 800 nm) of the support sheet can be calculated.

[0143] The average value of the light transmittance (400 to 800 nm) of the support sheet can be adjusted, for example, by adjusting the type and content of the components contained in the base material, the roughness of both surfaces of the base material (for example, surface roughness (Ra)), etc. Further, the average value of the light transmittance (400 to 800 nm) of the support sheet can also be adjusted by adjusting the type and content of the components contained in the adhesive layer.

[0144] <An example of the support sheet> In addition to the adhesive force (X1), the support sheet preferably has one or more selected from the group consisting of the adhesive force (X2), the adhesive force (Y1), the adhesive force (Y2), the adhesive force (X0), and the average value of the light transmittance (400 to 800 nm) within any of the above numerical ranges. That is, as an example of a preferable support sheet, for example, the following condition (1-1): (1-1) The adhesive force (X1) between the energy ray-cured product of the adhesive layer after heating and the silicon mirror wafer is 400 mN / 25 mm or less. satisfies, and the following conditions (1-2) to (1-6): (1-2) The adhesive force (X2) between the adhesive layer after heating and the silicon mirror wafer is 13000 mN / 25 mm or more. (1-3) The adhesive force (Y1) between the energy ray-cured product of the adhesive layer after heating and the SUS plate is 300 mN / 25 mm or more. (1-4) The adhesive force (Y2) between the adhesive layer after heating and the SUS plate is 13000 mN / 25 mm or more. (1-5) The adhesive force (X0) between the adhesive layer and the silicon mirror wafer is 2000 mN / 25 mm or more. (1-6) The average light transmittance (400-800 nm) of the support sheet is 80% or higher. A support sheet that satisfies one or more conditions selected from the group consisting of the following: A more preferable example of a support sheet is, for instance, a support sheet that satisfies all of the above conditions (1-1) to (1-6). In the support sheet illustrated here, it is particularly preferable that one or more values ​​selected from the group consisting of the average values ​​of adhesive strength (X1), adhesive strength (X2), adhesive strength (Y1), adhesive strength (Y2), adhesive strength (X0), and light transmittance (400-800 nm) are further limited to one of the numerical ranges described above.

[0145] ◇Method of manufacturing support sheets The support sheet can be manufactured by laminating the aforementioned layers that constitute it in corresponding positional relationships, and adjusting the shape of some or all of the layers as necessary. The method for forming each layer is as described above. For example, a support sheet can be manufactured by applying the above-mentioned adhesive composition (I) to one side (the matte side) of a substrate and drying it as needed.

[0146] A support sheet can also be manufactured by applying an adhesive composition (I) to one side of a release film, drying it as needed to form an adhesive layer on the release film, and then bonding the exposed side of this adhesive layer to one side (matte side) of a substrate. In this case, it is preferable to apply the adhesive composition (I) to the release-treated side of the release film.

[0147] The pressure applied when bonding the adhesive layer to the substrate (bonding pressure) is preferably 0.2 to 0.6 MPa. A pressure above the lower limit allows for sufficiently high adhesion between the adhesive layer and the substrate, and also enhances the embedding ability of the adhesive layer into the matte surface of the substrate. A pressure below the upper limit avoids excessive pressure. The bonding of such an adhesive layer to the substrate is preferably carried out under temperature conditions of 15°C or higher, but may also be carried out at room temperature.

[0148] A support sheet having the aforementioned other layer can be manufactured, for example, by applying a composition for forming the other layer to a suitable location on the substrate or adhesive layer, drying it as necessary to form the other layer, and then laminating any further necessary layers as needed. Alternatively, it can be manufactured by laminating a film-like other layer to a suitable location on the substrate or adhesive layer to provide the other layer, and then laminating any further necessary layers as needed.

[0149] ◇ Composite sheet for forming protective film The support sheet can be laminated with a protective film forming film to form a protective film-forming composite sheet. That is, the protective film-forming composite sheet comprises the support sheet and a protective film-forming film provided on the surface of the adhesive layer in the support sheet opposite to the substrate side. More specifically, the protective film-forming composite sheet comprises a substrate, an adhesive layer provided on one surface of the substrate, and a protective film-forming film provided on the surface of the adhesive layer opposite to the substrate side. The protective film-forming composite sheet may further include a release film provided on the surface of the protective film-forming film opposite to the adhesive layer side.

[0150] <<Protective film-forming film>> The protective film-forming film is a film for forming a protective film on any part of the workpiece. By using the protective film-forming composite sheet, a workpiece with a protective film can be manufactured, comprising a workpiece and a protective film provided on any part of the workpiece. For example, if the workpiece is a wafer, a chip with a protective film can be manufactured, comprising a chip and a protective film provided on the back surface of the chip, by using the protective film-forming composite sheet.

[0151] The protective film-forming film may be curable or non-curable. That is, the protective film-forming film may function as a protective film upon curing, or it may function as a protective film in an uncured state. The curable protective film may be either thermosetting or energy ray curable, or it may possess both thermosetting and energy ray curable properties.

[0152] The protective film may consist of one layer (single layer) or of two or more layers. If the protective film consists of multiple layers, these layers may be identical or different, and the combination of these layers is not particularly limited.

[0153] Examples of thermosetting protective film-forming films include those containing a polymer component (A) and a thermosetting component (B). Examples of polymer component (A) include acrylic resin, urethane resin, phenoxy resin, silicone resin, saturated polyester resin, and the like. Examples of thermosetting components (B) include epoxy-based thermosetting resins, thermosetting polyimide resins, and unsaturated polyester resins. In this specification, thermosetting polyimide resin is a general term encompassing a polyimide precursor and a thermosetting polyimide, both of which form a polyimide resin through thermosetting. The epoxy-based thermosetting resin comprises an epoxy resin (B1) and a thermosetting agent (B2).

[0154] In addition to these components, the thermosetting protective film may further contain one or more selected from the group consisting of a curing accelerator (C), a filler (D), a coupling agent (E), a crosslinking agent (F), an energy ray curable resin (G), a photopolymerization initiator (H), a colorant (I), and a general-purpose additive (J).

[0155] Examples of energy-ray curable protective film-forming films include those containing an energy-ray curable component (a). Examples of the energy ray curable component (a) include a polymer (a1) having an energy ray curable group and a weight-average molecular weight of 80,000 to 2,000,000, and a compound (a2) having an energy ray curable group and a molecular weight of 100 to 80,000.

[0156] The energy-ray curable protective film preferably contains, in addition to the energy-ray curable component (a), a polymer (b) that does not have energy-ray curable groups. Examples of polymers (b) that do not have energy-ray curable groups include acrylic resins, urethane resins, phenoxy resins, silicone resins, and saturated polyester resins.

[0157] The energy-ray curable protective film may further contain, in addition to the energy-ray curable component (a) and the polymer (b) that does not have an energy-ray curable group, one or more selected from the group consisting of colorants, thermosetting components, thermosetting agents, fillers, coupling agents, crosslinking agents, photopolymerization initiators, and general-purpose additives.

[0158] Examples of non-curing protective film-forming films include those containing polymer components. Examples of the polymer component include polymer component (A) mentioned above as a component of the thermosetting protective film, similar to non-curable resins.

[0159] The non-curing protective film may further contain, in addition to the polymer component, one or more substances selected from the group consisting of colorants, fillers, coupling agents, crosslinking agents, and general-purpose additives.

[0160] The thickness of the protective film is preferably 1 to 100 μm. A protective film with a thickness greater than or equal to the lower limit can be formed. A protective film with a thickness less than or equal to the upper limit can be avoided. Here, "thickness of protective film" refers to the total thickness of the protective film. For example, the thickness of a protective film consisting of multiple layers refers to the total thickness of all the layers that make up the protective film.

[0161] A protective film can be formed using a protective film-forming composition containing its constituent materials (a thermosetting protective film-forming composition for forming a thermosetting protective film, an energy ray-curable protective film-forming composition for forming an energy ray-curable protective film, and a non-curable protective film-forming composition for forming a non-curable protective film). For example, a protective film can be formed by coating the surface to be formed with the protective film-forming composition and drying it as necessary. The ratio of components that do not vaporize at room temperature in the protective film-forming composition is usually the same as the ratio of those components in the protective film-forming film.

[0162] ◇Method for manufacturing a composite sheet for forming a protective film The aforementioned composite sheet for forming the protective film can be manufactured by laminating the aforementioned layers in corresponding positional relationships and, if necessary, adjusting the shape of some or all of the layers. The method for forming each layer is as described above. For example, a protective film-forming composition can be applied to one side of a release film and dried as necessary to form a protective film on the release film. A protective film-forming composite sheet can then be manufactured by bonding the exposed side of this protective film-forming film (the side opposite to the release film side) to the exposed side of the adhesive layer in the support sheet (the side opposite to the substrate side). It is preferable to apply the protective film-forming composition to the release treatment side of the release film.

[0163] ◇Manufacturing method for workpieces (Method of using support sheets) The support sheet can be used in the manufacture of workpieces. In other words, a method for manufacturing a workpiece according to one embodiment of the present invention includes: an attachment step of fixing a workpiece with a support sheet, comprising the workpiece and the support sheet provided on the workpiece, to the ring frame by attaching the adhesive layer in the support sheet to the workpiece and the ring frame; a heating step of heating the adhesive layer in the support sheet fixed to the ring frame after the attachment step; a processing step of manufacturing the workpiece by processing the workpiece in the workpiece with support sheet fixed to the ring frame after the attachment step; a curing step of curing the adhesive layer attached to the ring frame with energy rays after the heating step and the processing step; and a pickup step of separating and picking up the workpiece from the cured adhesive layer after the curing step.

[0164] A manufacturing method for a workpiece when the workpiece is a semiconductor wafer, that is, a manufacturing method for a semiconductor chip, includes: an attachment step of fixing a semiconductor wafer with a support sheet, which comprises the semiconductor wafer and the support sheet provided on the semiconductor wafer, to the ring frame by attaching the adhesive layer in the support sheet to the semiconductor wafer and the ring frame; a heating step of heating the adhesive layer in the support sheet fixed to the ring frame after the attachment step; a processing step of producing the semiconductor chip by dividing the semiconductor wafer in the semiconductor wafer with support sheet fixed to the ring frame after the attachment step; a curing step of curing the adhesive layer attached to the ring frame with energy rays after the heating step and the processing step; and a pickup step of separating and picking up the semiconductor chip from the cured adhesive layer after the curing step.

[0165] The order in which the heating step and the processing step are performed after the bonding step can be arbitrarily selected according to the purpose. For example, the heating step may be performed before the processing step, or the processing step may be performed before the heating step. For example, in the manufacturing method, the heating step may be performed to remove foreign matter such as low molecular weight resin components adhering to the surface of the workpiece by volatilization. In this case, the heating step may be performed either before or after the processing step. Also, in the manufacturing method, after washing and removing fine foreign matter that is generated during processing such as dicing of the workpiece and adheres to the surface of the workpiece with water, the heating step may be performed to dry the workpiece. In this case, the heating step is performed after the processing step. Furthermore, in the manufacturing method, the heating step for removing these foreign matter and the heating step for drying may be performed together, or these heating steps may be performed in a single step.

[0166] <<An example of a manufacturing method for a workpiece>> Figure 2 is a schematic cross-sectional view illustrating an example of the manufacturing method when the workpiece is a semiconductor wafer. Here, we will describe the manufacturing method using the support sheet 1 shown in Figure 1.

[0167] <Pasting process> In the aforementioned attachment process, the adhesive layer 12 in the support sheet 1 is attached to the semiconductor wafer 9 (more specifically, the back surface 9b of the semiconductor wafer 9) and the ring frame 8, thereby fixing the semiconductor wafer 109 with a support sheet, which comprises the semiconductor wafer 9 and the support sheet 1 provided on the back surface 9b of the semiconductor wafer 9, to the ring frame 8, as shown in Figure 2(a). The semiconductor wafer 109 with a support sheet is the workpiece with a support sheet. The support sheet 1 is used after removing the release film 13. The side 12a of the adhesive layer 12 opposite to the substrate 11 is the same as one side 1a of the support sheet 1 (the side facing the adhesive layer 12). In Figure 2, bumps and other features on the circuit surface 9a of the semiconductor wafer 9 are omitted from the illustration.

[0168] In the bonding process, the central portion of the adhesive layer 12 in the width direction is bonded to the semiconductor wafer 9, and the surrounding portion is bonded to the ring frame 8.

[0169] The support sheet 1 (adhesive layer 12) can be attached to the semiconductor wafer 9 and ring frame 8 at room temperature. The attachment speed when attaching the support sheet 1 (adhesive layer 12) to the semiconductor wafer 9 and ring frame 8 is not particularly limited, but is preferably 200 to 400 mm / min.

[0170] <Heating process> After the bonding step, in the heating step, as shown in Figure 2(b), the adhesive layer 12 in the support sheet 1 fixed to the ring frame 8 is heated. In this case, heating of the adhesive layer 12 is associated with heating the entire semiconductor wafer 109 with the support sheet attached, and this heating allows for the removal of foreign substances such as low molecular weight resin components adhering to the surface of the semiconductor wafer 9 (e.g., the circuit surface 9a) by volatilization.

[0171] The heating temperature of the adhesive layer 12 (semiconductor wafer 109 with support sheet) is preferably 100 to 135°C. A heating temperature above the lower limit ensures sufficient heating effects. A heating temperature below the upper limit avoids excessive heating, suppressing, for example, the degradation of the semiconductor wafer 109 with support sheet.

[0172] If the adhesive strength (Y2) of the support sheet 1 is 13,000 mN / 25 mm or more, then even if the semiconductor wafer 109 with the support sheet is heated while fixed to the ring frame 8 during the heating process, peeling of the semiconductor wafer 109 with the support sheet from the ring frame 8 is suppressed.

[0173] <Processing process> After the bonding and heating steps, in the processing step, as shown in Figure 2(c), the semiconductor wafer 9 in the heated semiconductor wafer 109 with a support sheet fixed to the ring frame 8 is divided to produce a semiconductor chip 90, which is the workpiece. The processing step yields a semiconductor chip group 901 with a support sheet, in which multiple semiconductor chips 90 are aligned and held on a single support sheet 1.

[0174] Reference numeral 90a indicates the circuit surface of the semiconductor chip 90, which corresponds to the circuit surface 9a of the semiconductor wafer 9. The reference numeral 90b indicates the back surface of the semiconductor chip 90, which corresponds to the back surface 9b of the semiconductor wafer 9.

[0175] The semiconductor wafer 9 can be divided by known methods. For example, the semiconductor wafer 9 can be divided by various dicing methods such as blade dicing using a blade, laser dicing using laser irradiation, or water dicing by spraying water containing an abrasive. Furthermore, the semiconductor wafer 9 can also be divided by using a semiconductor wafer 9 that has a modified layer formed by stealth dicing (registered trademark) and has not been divided, and by expanding the semiconductor wafer 9 in a direction parallel to its circuit surface 9a or back surface 9b.

[0176] Stealth dicing (registered trademark) is a method described below. First, a section to be divided is set within the semiconductor wafer, and a laser beam is irradiated to focus on this section, thereby forming a modified layer within the semiconductor wafer. Unlike other parts of the semiconductor wafer, the modified layer is altered by the laser beam irradiation and has weakened strength. Therefore, when force is applied to the semiconductor wafer, cracks extending in both directions of the semiconductor wafer are generated in the modified layer within the semiconductor wafer, becoming the starting point for the division (cutting) of the semiconductor wafer. Next, force is applied to the semiconductor wafer to divide it at the location of the modified layer, and a semiconductor chip is manufactured.

[0177] In the case of the support sheet 1, if the adhesive force (X2) is 13,000 mN / 25 mm or more, even after the support sheet 1 with the semiconductor wafer 9 attached (in other words, the semiconductor wafer 109 with the support sheet attached) is heated to a high temperature with an upper limit of approximately 135°C in the heating step, peeling of the semiconductor chip 90 from the support sheet 1 (adhesive layer 12) is suppressed even if a large force is applied to the semiconductor chip 90 in the processing step, such as by splitting the semiconductor wafer 9 or washing the semiconductor chip 90 with water.

[0178] In the support sheet 1, if the adhesive force (X0) is 2000 mN / 25 mm or more, even if a large force is applied to the semiconductor chip 90 during the processing step by rapidly dividing the semiconductor wafer 9 into small semiconductor chips 90, or by washing the small semiconductor chips 90 with a lot of cutting debris attached to them with high-pressure water, the peeling of the semiconductor chip 90 from the support sheet 1 (adhesive layer 12) is suppressed.

[0179] <Curing process> After the heating and processing steps, in the curing step, as shown in Figure 2(d), the adhesive layer 12 attached to the ring frame 8 is cured by energy rays. The curing step yields a group of semiconductor chips 901' with a cured support sheet, in which multiple semiconductor chips 90 are aligned and held on a single cured support sheet 1'. The support sheet 1 becomes a cured support sheet 1' when the adhesive layer 12 is cured by energy rays, becoming an energy ray cured product 12'. The semiconductor chip group 901' with a cured support sheet is a laminate of the workpiece and the cured support sheet as described above (in other words, a workpiece with a cured support sheet), and is the same as the semiconductor chip group 901 with a support sheet, except that the adhesive layer 12 is its energy ray cured product 12'.

[0180] During energy ray curing of the adhesive layer 12 (when energy rays are irradiated onto the adhesive layer 12), the irradiance of the energy rays is 60-320 mW / cm². 2 Preferably, the amount of energy rays is 100-1000 mJ / cm². 2 It is preferable that this be the case. It is preferable that the energy rays are irradiated onto the adhesive layer 12 from outside the support sheet 1, through the substrate 11 (via the substrate 11).

[0181] In the case of the support sheet 1, if the adhesive force (Y1) is 300 mN / 25 mm or more, the semiconductor wafer 109 with the support sheet is heated while fixed to the ring frame 8 during the heating process, and even if energy rays are irradiated to the contact portion of the support sheet 1 (adhesive layer 12) with the ring frame 8 during the curing process, peeling of the cured semiconductor chip group 901' with the support sheet from the ring frame 8 is suppressed.

[0182] <Pickup Process> After the curing process, in the pickup process, as shown in Figure 2(e), the semiconductor chip 90 can be separated and picked up from the energy ray cured product 12' of the adhesive layer in the cured support sheet 1', thereby allowing the target semiconductor chip 90 to be extracted from the group of semiconductor chips 901' with the cured support sheet. Here, the direction of pickup is indicated by the arrow P.

[0183] When the semiconductor chip 90 is picked up, delamination occurs between the back surface 90b of the semiconductor chip 90 and the side 12a' of the energy-ray cured adhesive layer 12' opposite to the substrate 11. At this time, the adhesive force between the energy-ray cured adhesive layer 12' and the semiconductor chip 90 is smaller than the adhesive force between the adhesive layer 12 and the semiconductor chip 90, so the semiconductor chip 90 can be easily peeled off from the energy-ray cured adhesive layer 12' and easily picked up. The side 12a' of the energy-ray cured adhesive layer 12' opposite to the substrate 11 side corresponds to the side 12a of the adhesive layer 12 opposite to the substrate 11 side, and is the same as one side (the side of the energy-ray cured adhesive layer 12' side) 1a' of the cured support sheet 1'.

[0184] The semiconductor chip 90 can be picked up by known methods. For example, a vacuum collet or the like can be used as a separation means 7 for separating the semiconductor chip 90 from the cured support sheet 1' (energy ray cured product 12' of the adhesive layer).

[0185] In the support sheet 1, the adhesive force (X1) is 400 mN / 25 mm or less. Therefore, even after heating the support sheet 1 with the semiconductor wafer 9 attached (in other words, the semiconductor wafer 109 with the support sheet attached) at a high temperature with an upper limit of approximately 135°C during the heating process, the semiconductor chip 90 can be fabricated from the semiconductor wafer 9 on the support sheet 1, and the semiconductor chip 90 can be picked up normally from the cured support sheet 1', resulting in high pickability.

[0186] <Other processes> The above manufacturing method may include other steps that do not fall under any of the following categories: the bonding step, the heating step, the processing step, the curing step, or the picking step. The types of other processes, the number of other processes, and the timing of performing these other processes can all be arbitrarily selected according to the purpose and are not particularly limited.

[0187] <<Other examples of methods for manufacturing workpieces>> Up to this point, we have described a method for manufacturing a workpiece in which the bonding process, heating process, processing process, curing process, and pickup process are performed in this order (hereinafter sometimes referred to as "manufacturing method (1)"). However, the method for manufacturing a workpiece in this embodiment is not limited to this (manufacturing method (1)). For example, in the above manufacturing method, as described above, the order in which the heating process and processing process are performed may be reversed.

[0188] <Pasting process> In this method of manufacturing a workpiece (hereinafter sometimes referred to as "manufacturing method (2)"), a bonding step is performed first. The bonding step in manufacturing method (2) is the same as the bonding step in manufacturing method (1).

[0189] <Processing process> In the processing step, following the bonding step in manufacturing method (2), a semiconductor chip, which is the workpiece, is produced by dividing the semiconductor wafer in the unheated semiconductor wafer with a support sheet fixed to the ring frame. The processing step yields a group of semiconductor chips with support sheets, which is the same as in manufacturing method (1), except that they are not heated.

[0190] In the support sheet, if the adhesive force (X0) is 2000 mN / 25 mm or more, even if a large force is applied to the semiconductor chip during the processing step, such as by rapidly dividing the semiconductor wafer into small semiconductor chips or washing the small semiconductor chips with a lot of cutting debris attached to them with high-pressure water, the peeling of the semiconductor chip from the support sheet (adhesive layer) is suppressed.

[0191] <Heating process> In the heating step, after the bonding and processing steps of manufacturing method (2), the adhesive layer in the support sheet fixed to the ring frame is heated. In this case, heating of the adhesive layer is associated with heating the entire semiconductor chip group with the support sheet. This heating allows for the removal of foreign matter, such as low molecular weight resin components adhering to the surface of the semiconductor chip (e.g., the circuit side), by volatilization. Furthermore, after washing and removing fine foreign matter generated during semiconductor wafer dicing and adhering to the surface of the semiconductor chip with water, the semiconductor chip can be dried by this heating. The heating step yields a semiconductor chip group with a support sheet similar to that of manufacturing method (1).

[0192] In the case of the support sheet, if the adhesive force (X2) is 13,000 mN / 25 mm or more, then in the heating process, even if a large force is applied to the semiconductor chip after the support sheet with the semiconductor chip attached (in other words, the group of semiconductor chips with the support sheet) is heated to a high temperature with an upper limit of approximately 135°C, peeling of the semiconductor chip from the support sheet (adhesive layer) is suppressed.

[0193] In the case of the support sheet, if the adhesive strength (Y2) is 13,000 mN / 25 mm or more, even if the semiconductor chip group with the support sheet is heated while fixed to the ring frame during the heating process, peeling of the semiconductor chip group with the support sheet from the ring frame is suppressed.

[0194] <Curing process> After the heating step and processing step of manufacturing method (2), the curing step can be performed in the same manner as in manufacturing method (1), and the curing step yields a group of semiconductor chips with cured support sheets in the same manner as in manufacturing method (1).

[0195] In the case of the support sheet, if the adhesive force (Y1) is 300 mN / 25 mm or more, in the heating step, the support sheet with the semiconductor chips attached (in other words, the group of semiconductor chips with the support sheet) is heated while fixed to the ring frame, and furthermore, in the curing step, even if energy rays are irradiated to the contact portion of the support sheet (adhesive layer) with the ring frame, peeling of the cured support sheet with semiconductor chips from the ring frame is suppressed.

[0196] <Pickup Process> After the curing step in manufacturing method (2), the pickup step can be performed in the same manner as in manufacturing method (1), and the target semiconductor chip can be extracted by the pickup step in the same manner as in manufacturing method (1).

[0197] In the support sheet, the adhesive strength (X1) is 400 mN / 25 mm or less, so that even after the semiconductor chip group with the support sheet is heated to a high temperature with an upper limit of approximately 135°C in the heating process, the semiconductor chips can be picked up normally from the cured support sheet, resulting in high pickability.

[0198] <Other processes> Manufacturing method (2) may include other steps similar to those in manufacturing method (1). In manufacturing method (2), the type of other process, the number of other processes, and the timing of performing the other processes can all be arbitrarily selected according to the purpose and are not particularly limited. [Examples]

[0199] The present invention will be described in more detail below with reference to specific examples. However, the present invention is not limited in any way to the examples shown below.

[0200] <Raw materials for resin manufacturing> The full names of the resin manufacturing raw materials, which are abbreviated in this example and comparative example, are shown below. 2EHA: 2-ethylhexyl acrylate 2EHMA: 2-ethylhexyl methacrylate HEA: 2-hydroxyethyl acrylate HEMA: 2-hydroxyethyl methacrylate MOI: 2-Methacryloyloxyethyl isocyanate

[0201] <Raw materials for the manufacture of adhesive composition (I)> In this example and comparative example, the raw materials used in the production of the adhesive composition (I) are as follows. The viscosity of the four crosslinking agents (β) at 23°C was measured using a Viscotec digital rotational viscometer, "ViscoLead Advance". [Energy ray curable compound (α)] (α)-1:2-(2-phenoxyethoxy)ethyl acrylate, manufactured by Shin Nakamura Chemical Industry Co., Ltd., "AMP-20GY", viscosity at 23°C 18 mPa·s, molecular weight 236.1 (α)-2: R-684 manufactured by Nippon Kayaku Co., Ltd., viscosity at 23°C 180 mPa·s, molecular weight 304.4) (α)-3: (2-(1-(acryloyloxy)-2-methylpropan-2-yl)-5-ethyl-1,3-dioxan-5-yl)methyl acrylate, manufactured by Shin Nakamura Chemical Industry Co., Ltd., "A-DOG", viscosity at 23℃: 310 mPa·s, molecular weight: 326.4) [Other energy-ray-curable compounds (α')] (α')-1: ATM-4E manufactured by Shin-Nakamura Chemical Industry Co., Ltd., viscosity at 23℃: 360 mPa·s, molecular weight: 528.6 [Crosslinking agent (β)] (β)-1:1,6-hexamethylene diisocyanate trimethylolpropane adduct (Tosoh Corporation's "Coronate HL") (β)-2: Isocyanurate modified form of hexamethylene diisocyanate (Tosoh Corporation's "Coronate HX") [Photopolymerization initiator (γ)] (γ)-1:2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one (IGM Resins "Omnirad® 127")

[0202] [ka]

[0203] Furthermore, both energy-ray curable compounds (α)-1 and (α)-3 are substituted acrylic acid esters. In energy-ray curable compound (α)-1, the hydrocarbon group derived from the alcohol has 2 substituents and the hydrocarbon group has 12 carbon atoms. In energy-ray curable compound (α)-3, the hydrocarbon group derived from the alcohol has 2 substituents and the hydrocarbon group has 13 carbon atoms. On the other hand, energy-ray curable compound (α)-2 is an acrylic acid ester without substituents. In energy-ray curable compound (α)-2, the hydrocarbon group derived from the alcohol has 12 carbon atoms.

[0204] [Example 1] <<Manufacturing of support sheets>> <Manufacturing of energy-ray curable acrylic resin (Ia)> Energy-ray curable acrylic resin (Ia)-1 was obtained by adding MOI to acrylic polymer (1) and carrying out an addition reaction at 50°C for 48 hours in an air stream. The acrylic polymer (1) is a copolymer of 2EHA (35 parts by mass), 2EHMA (45 parts by mass), and HEMA (20 parts by mass). The amount of MOI used was such that the total number of isocyanate groups in the MOI was 0.95 times the total number of hydroxyl groups derived from HEMA in the acrylic polymer (1). The weight-average molecular weight of the obtained energy-ray curable acrylic resin (Ia)-1 was 440,000, and the glass transition temperature was -26°C.

[0205] <Manufacturing of adhesive composition (I)> An energy-ray-curable adhesive composition (I)-1 was prepared, containing energy-ray-curable acrylic resin (Ia)-1 (100 parts by mass), energy-ray-curable compound (α)-1 (15 parts by mass), crosslinking agent (β)-1 (1.17 parts by mass), and photopolymerization initiator (γ)-1 (3 parts by mass), and further containing methyl ethyl ketone as a solvent, with the total concentration of all components other than the solvent being 25% by mass. Note that the content of components other than methyl ethyl ketone shown herein is the content of the target product excluding the solvent.

[0206] <Formation of the adhesive layer> A release film (second release film) made of polyethylene terephthalate film, in which one side was peeled by silicone treatment, was used. The adhesive composition (I)-1 obtained above was applied to the peeled surface and heated and dried at 100°C for 2 minutes to form an energy ray curable adhesive layer with a thickness of 15 μm.

[0207] <Manufacturing of support sheets> Next, at room temperature, a polypropylene film (manufactured by Dia Plus Film Co., Ltd., 80 μm thick) was bonded to the exposed surface of the adhesive layer at a bonding speed of 5 m / min and under pressure of 0.4 MPa. One side of this polypropylene film was a matte surface with a surface roughness (Ra) of 0.90 μm, and the other side was a fine matte surface with a surface roughness (Ra) of 0.12 μm. The adhesive layer was then bonded to the matte surface of this polypropylene film. Based on the above, the desired support sheet was obtained.

[0208] <<Evaluation of the support sheet>> <Measurement of adhesive strength (X1) between the energy ray cured adhesive layer after heating and the silicon mirror wafer> From the support sheet obtained above, a test piece with a width of 25 mm was cut out. Under bonding temperature conditions of 23°C (laminating roller temperature 23°C, silicon mirror wafer temperature 23°C), with a bonding speed of 300 mm / min and a bonding pressure of 0.3 MPa, the test piece was bonded to the mirror surface of a silicon mirror wafer (thickness 650 nm) using the adhesive layer within it, thereby obtaining a silicon mirror wafer with the test piece attached. This silicon mirror wafer with the test piece attached was placed inside an oven heated to 130°C and heated at this temperature (130°C) for 2 hours. Next, the silicon mirror wafer with the test specimen attached was removed from the oven and cooled to 23°C by air cooling. Then, an illuminance of 230 mW / cm² was applied using an ultraviolet irradiation device (Lintec RAD-2000UV). 2 , light intensity 200mJ / cm 2 Under these conditions, the adhesive layer in the silicon mirror wafer with the extracted test specimen was cured by irradiating it with ultraviolet light through the substrate.

[0209] Next, in an environment of 23°C, with a peeling speed of 300 mm / min, the test piece was peeled from the silicon mirror wafer. At this time, the test piece was peeled in the length direction so that the surface of the silicon mirror wafer where the test piece was attached and the surface of the test piece where the silicon mirror wafer was attached formed an angle of 180° (180° peeling was performed). Then, the load (peeling force) at the time of this 180° peeling was measured. With the measurement length being 50 mm, the measured values for the first 5 mm length and the measured values for the last 5 mm length were excluded from the valid values. And the average value of those measured values was adopted as the adhesive force (mN / 25 mm). Such measurement of the adhesive force was performed twice, and the average value at that time was adopted as the adhesive force (X1) (mN / 25 mm) between the energy ray-cured product of the adhesive layer after heating and the silicon mirror wafer. The results are shown in Table 1.

[0210] <Measurement of the adhesive force (X2) between the adhesive layer after heating and the silicon mirror wafer> A silicon mirror wafer with a test piece was produced in the same manner as when measuring the above adhesive force (X1), heated at 130°C for 2 hours, and cooled by natural cooling until the temperature reached 23°C. Next, in an environment of 23°C, with a peeling speed of 300 mm / min, the test piece was peeled from this cooled silicon mirror wafer. At this time, the test piece was peeled in the length direction so that the surface of the silicon mirror wafer where the test piece was attached and the surface of the test piece where the silicon mirror wafer was attached formed an angle of 180° (180° peeling was performed). Then, the load (peeling force) at the time of this 180° peeling was measured. With the measurement length being 50 mm, the measured values for the first 5 mm length and the measured values for the last 5 mm length were excluded from the valid values. And the average value of those measured values was adopted as the adhesive force (mN / 25 mm). Such measurement of the adhesive force was performed twice, and the average value at that time was adopted as the adhesive force (X2) (mN / 25 mm) between the adhesive layer after heating and the silicon mirror wafer. The results are shown in Table 1.

[0211] <Measurement of the Adhesive Force (Y1) between the Energy Ray Cured Product of the Adhesive Layer after Heating and the SUS Plate> The test piece was attached to the #1200 polished surface of a SUS plate (manufactured by Partech Co., Ltd., "SUS304 #1200HL, thickness 1000 μm, size 70 mm × 150 mm") instead of the mirror surface of the silicon mirror wafer. A SUS plate with a test piece was obtained in the same manner as when measuring the adhesive force (X1) described above, except for this point. Next, for this SUS plate with a test piece, it was heated at 130°C for 2 hours in the same manner as in the case of the silicon mirror wafer with a test piece when measuring the adhesive force (X1) described above, and cooled by natural cooling until its temperature reached 23°C. Then, the adhesive layer in the test piece on the SUS plate with a test piece was cured by ultraviolet irradiation through the substrate.

[0212] Next, in an environment at 23°C, with a peeling speed of 300 mm / min, the test piece was peeled from the SUS plate. At this time, the test piece was peeled in the longitudinal direction so that the surface of the SUS plate where the test piece was attached and the surface of the test piece where the SUS plate was attached formed an angle of 180° (180° peeling was performed). Then, the load (peeling force) during this 180° peeling was measured. With a measurement length of 50 mm, the measured values for the first 5 mm length and the last 5 mm length were excluded from the valid values. And the average value of the measured values was adopted as the adhesive force (mN / 25 mm). Such measurement of the adhesive force was performed twice, and the average value at that time was adopted as the adhesive force (Y1) (mN / 25 mm) between the energy ray cured product of the adhesive layer after heating and the SUS plate. The results are shown in Table 1.

[0213] <Measurement of the Adhesive Force (Y2) between the Adhesive Layer after Heating and the SUS Plate> A SUS plate with a test piece was prepared in the same manner as when measuring the adhesive force (Y1) described above, heated at 130°C for 2 hours, and cooled by natural cooling until its temperature reached 23°C. Next, under conditions of 23°C, the test specimen was peeled off the cooled SUS plate at a peeling speed of 300 mm / min. At this time, the test specimen was peeled in its longitudinal direction such that the surface of the SUS plate to which the test specimen was attached and the surface of the test specimen to which the SUS plate was attached formed an angle of 180° (180° peeling was performed). The load (peeling force) at the time of this 180° peeling was measured, and the measurement length was set to 50 mm. The measurement values ​​for the first 5 mm and the last 5 mm were excluded from the valid values. The average of these measurement values ​​was then adopted as the adhesive strength (mN / 25 mm). The adhesive strength was measured twice, and the average value was used as the adhesive strength (Y2) (mN / 25mm) between the heated adhesive layer and the SUS plate. The results are shown in Table 1.

[0214] <Measurement of adhesive strength (X0) between the adhesive layer and the silicon mirror wafer> A silicon mirror wafer with a test piece attached was prepared using the same method as when measuring the adhesive strength (X1) described above. Next, the silicon mirror wafer with the test specimen attached was left to stand for 30 minutes under a temperature of 23°C. Next, under conditions of 23°C, the test specimen was peeled off the silicon mirror wafer after static storage at a peeling speed of 300 mm / min. At this time, the test specimen was peeled in its longitudinal direction such that the surface of the silicon mirror wafer to which the test specimen was attached and the surface of the test specimen to which the silicon mirror wafer was attached formed an angle of 180° (180° peeling was performed). The load (peeling force) at the time of this 180° peeling was measured, and the measurement length was set to 50 mm. The measurement values ​​for the first 5 mm and the measurement values ​​for the last 5 mm were excluded from the valid values. The average of these measurement values ​​was then adopted as the adhesive strength (mN / 25 mm). The adhesive strength was measured twice, and the average value was adopted as the adhesive strength (X0) (mN / 25mm) between the adhesive layer and the silicon mirror wafer. The results are shown in Table 1.

[0215] <Calculation of the average light transmittance (400-800nm) of the support sheet, and evaluation of the embedding properties of the adhesive layer on the matte surface of the substrate> Using a UV-vis measuring device (Shimadzu Corporation's "UV-vis-NIR3600"), the support sheet obtained above was irradiated with light from the outside of the substrate side, and the light transmittance was measured by direct light reception without using an integrating sphere. The wavelength range for this measurement was 190 to 2000 nm. The light transmittance values ​​were then added up for every 1 nm in the visible light wavelength range of 400 to 800 nm, and the average value (%) of the light transmittance (400 to 800 nm) of the support sheet was calculated by dividing the sum by the number of added light transmittance values ​​(i.e., 800 - 400 + 1 = 401). From this average value, the embedding ability of the adhesive layer on the matte surface of the substrate was evaluated according to the following criteria. These results are shown in Table 1. (Evaluation Criteria) A: The average light transmittance (400-800nm) of the support sheet is 80% or higher, and the adhesive layer on the matte surface of the substrate provides high embedding properties. B: The average light transmittance (400-800nm) of the support sheet is less than 80%, indicating insufficient embedding by the adhesive layer on the matte surface of the substrate.

[0216] <Evaluation of the accuracy of chipping inspection for support sheets> (Manufacturing of silicon chip groups with support sheets) An 8-inch silicon wafer (350 μm thick) with one side polished to #2000 grit was prepared. Of the adhesive layer in the support sheet obtained above, the central region in the width direction was attached to this silicon wafer, and the region surrounding the area attached to the silicon wafer was attached to the ring frame. At this time, the attachment of the adhesive layer to the silicon wafer and ring frame was performed under attachment temperature conditions of 23°C (laminate roller temperature 23°C, silicon wafer temperature 23°C), with an attachment speed of 300 mm / min and an attachment pressure of 0.3 MPa. In this way, the silicon wafer with the support sheet, which consisted of the silicon wafer and the support sheet provided on one side of the silicon wafer, was fixed to the ring frame (attachment process). Next, the silicon wafer with the support sheet fixed to the ring frame was placed inside the oven and heated at 130°C for 2 hours (heating process). Next, the silicon wafer with the support sheet fixed to the ring frame was removed from the oven and cooled to 23°C by air cooling. Then, using a dicing device (DISCO "DFD6362"), multiple silicon chips measuring 1 mm x 1 mm were produced by dicing the silicon wafer within the silicon wafer with the support sheet fixed to the ring frame (processing step). At this time, a DISCO "ZH05-SD2000-N1-90 CC" dicing blade was used, with a blade rotation speed of 20,000 rpm, a blade feed rate of 50 mm / s, and a blade height of 0.06 mm. The blade was inserted into the silicon wafer with the support sheet from the silicon wafer side surface and cut to a depth of 20 μm from the adhesive layer side surface of the substrate. Based on the above, a group of silicon chips with a support sheet was fabricated, in which multiple silicon chips are aligned and held on a single support sheet.

[0217] (Evaluation of the accuracy of chipping inspection of support sheets) From this group of silicon chips with support sheets, 100 silicon chips were selected from regions divided from the center and its vicinity on the silicon wafer before dicing, in two orthogonal directions, totaling 10 rows. Using an optical microscope (KEYENCE VHX-7000), the surfaces of these 100 silicon chips attached to the support sheets were observed at 200x magnification, with the focus directed through the support sheets. Each silicon chip was observed for approximately 1 second. The number of silicon chips with cracks or chips (chipping) of 100 μm or larger on the surface attached to the support sheets was then counted. This count was performed by three different observers, and the average value was calculated and adopted as the chipping count C1.

[0218] Next, under a temperature of 23°C, adhesive tape (Lintec's "PET50 PL Thin") was applied to the exposed surface (the side opposite to the support sheet) of all the silicon chips in the group of silicon chips with support sheets. This adhesive tape is composed of a base material with a thickness of 50 μm and an acrylic adhesive layer provided on one side of the base material. Next, using a UV irradiation device (Lintec RAD-2000UV), the adhesive layer in the silicone chip group with the support sheet attached, after the adhesive tape has been applied, is irradiated from the outside of the substrate side through the substrate at an illuminance of 230 mW / cm². 2 , light intensity 200mJ / cm 2 The adhesive layer was cured by UV irradiation under these conditions. Next, the cured support sheets were removed from the group of silicon chips with cured support sheets. Then, 100 silicon chips were selected from the exposed group, the same number as those used to calculate C1 above. Using an optical microscope (KEYENCE VHX-7000), the exposed surface (the surface that was attached to the support sheet) of these 100 silicon chips was focused at 200x magnification and observed. At this time, one observer spent a sufficient amount of time observing the silicon chips to avoid missing any abnormalities. The number of silicon chips with cracks or chips of 100 μm or larger (chipping) on ​​the exposed surface of the silicon chips was then confirmed to be C2.

[0219] The chipping inspection accuracy value was calculated according to the following formula (i), and the chipping inspection accuracy of the support sheet was evaluated according to the following criteria. The results are shown in Table 1. [Chipping inspection accuracy value] = (C2 - C1) / C2 × 100 (i) (Evaluation Criteria) A: The inspection accuracy value is less than 3, the chipping inspection accuracy of the support sheet is high, and the inspection accuracy is acceptable. B: The inspection accuracy value is between 3 and 10, which is inferior to A, but the chipping inspection accuracy of the support sheet is good, and the inspection accuracy is acceptable. C: The inspection accuracy value is 10 or higher, the chipping inspection accuracy of the support sheet is low, and the inspection accuracy is unsatisfactory.

[0220] <Evaluation of the pickability of silicon chips on the support sheet> (Manufacturing of silicon chip groups with support sheets) Using the same method as in the "Evaluation of Chipping Inspection Accuracy of Support Sheets" described above, the silicon wafer with the support sheet attached was fixed to a ring frame (attachment step), and this silicon wafer with the support sheet attached, fixed to the ring frame, was placed inside an oven and heated at 130°C for 2 hours (heating step). Next, the silicon wafer with the support sheet fixed to the ring frame was removed from the oven and cooled to 23°C by air cooling. Then, using a dicing device (DISCO "DFD6362"), multiple silicon chips measuring 3mm x 3mm were produced by dicing the silicon wafer within the silicon wafer with the support sheet fixed to the ring frame (processing step). At this time, a DISCO "ZH05-SD2000-N1-90 CC" dicing blade was used, with a blade rotation speed of 35000 rpm, a blade feed rate of 30 mm / s, and a blade height of 0.06 mm. The blade was inserted into the silicon wafer with the support sheet from the silicon wafer side surface and cut to a depth of 20 μm from the adhesive layer side surface of the substrate. Based on the above, a group of silicon chips with a support sheet was fabricated, in which multiple silicon chips are aligned and held on a single support sheet.

[0221] (Evaluation of the pickability of silicon chips on the support sheet) Next, using an ultraviolet irradiation device (Lintec RAD-2000UV), an illuminance of 230 mW / cm² was applied to the adhesive layer in the group of silicone chips with support sheets, from outside the substrate side, through the substrate. 2 , light intensity 200mJ / cm 2 By irradiating the ring frame with ultraviolet light under these conditions, the adhesive layer attached to the ring frame was cured with ultraviolet light (curing process). Next, using a pick-up die bonding apparatus ("BESTEM D-510" manufactured by Canon Machinery), the silicon chips of the silicon chip group with a cured support sheet were picked up by separating them from the cured product of the adhesive layer under the following pick-up conditions (pick-up process). This pick-up was performed on a total of 100 silicon chips in an area of 10 columns in two orthogonal directions, which were divided from the center and its vicinity in the silicon wafer before dicing among the silicon chips of the silicon chip group with a cured support sheet. One silicon chip was picked up by the method of pushing it up from the support sheet side with one pin. Then, the pick-up property of the support sheet was evaluated according to the following criteria. The results are shown in Table 1. (Pick-up conditions) Lifting speed: 5 mm / s Expansion amount: 4 mm Radius of curvature of the pin tip: 0.75 mm (Evaluation criteria) A: All (100) silicon chips were successfully picked up. B: 1 to 4 silicon chips could not be successfully picked up, but all other (96 to 99) silicon chips were successfully picked up. C: 5 or more silicon chips could not be successfully picked up.

[0222] [Example 2] [Manufacture and evaluation of the support sheet] An energy ray-curable adhesive composition (I)-2 having the same composition as in Example 1 except that the energy ray-curable compound (α)-3 (10 parts by mass) was contained instead of the energy ray-curable compound (α)-1 (15 parts by mass) and the content of the crosslinking agent (β)-1 was 1.33 parts by mass instead of 1.17 parts by mass was prepared. Then, the support sheet was manufactured and evaluated in the same manner as in Example 1 except that this adhesive composition (I)-2 was used instead of the adhesive composition (I)-1. The results are shown in Table 1.

[0223] [Example 3] <<Manufacturing and evaluation of support sheets>> Energy-ray curable adhesive composition (I)-3 was prepared, having the same composition as in Example 1, except that it contained energy-ray curable compound (α)-2 (10 parts by mass) instead of energy-ray curable compound (α)-1 (15 parts by mass), and the crosslinking agent (β)-1 content was 1.33 parts by mass instead of 1.17 parts by mass. Then, a support sheet was manufactured and evaluated in the same manner as in Example 1, except that adhesive composition (I)-3 was used instead of adhesive composition (I)-1. The results are shown in Table 1.

[0224] [Example 4] <<Manufacturing of support sheets>> <Manufacturing of energy-ray curable acrylic resin (Ia)> An addition reaction was carried out in an air stream at 50°C for 48 hours by adding MOI to the aforementioned acrylic polymer (1) to obtain energy-ray curable acrylic resin (Ia)-2. The amount of MOI used was such that the total number of isocyanate groups in the MOI was 0.785 times the total number of hydroxyl groups derived from HEMA in the acrylic polymer (1). The weight-average molecular weight of the obtained energy-ray curable acrylic resin (Ia)-2 was 500,000, and the glass transition temperature was -26°C.

[0225] <Manufacturing of adhesive composition (I)> An energy-ray-curable adhesive composition (I)-4 was prepared, containing energy-ray-curable acrylic resin (Ia)-2 (100 parts by mass), energy-ray-curable compound (α)-1 (25 parts by mass), crosslinking agent (β)-2 (4.12 parts by mass), and photopolymerization initiator (γ)-1 (3 parts by mass), and further containing methyl ethyl ketone as a solvent, with the total concentration of all components other than the solvent being 25% by mass. Note that the content of all components other than methyl ethyl ketone shown herein is the content of the target product excluding the solvent.

[0226] <Manufacturing of support sheets> The support sheet was manufactured in the same manner as in Example 1, except that adhesive composition (I)-4 was used instead of adhesive composition (I)-1.

[0227] <<Evaluation of the support sheet>> The support sheets obtained above were evaluated using the same method as in Example 1. The results are shown in Table 1.

[0228] [Comparative Example 1] <<Manufacturing of support sheets>> <Manufacturing of adhesive compositions> An energy-ray-curable adhesive composition (R)-1 was prepared, containing energy-ray-curable acrylic resin (Ia)-1 (100 parts by mass), crosslinking agent (β)-1 (0.53 parts by mass), and photopolymerization initiator (γ)-1 (3 parts by mass), and further containing methyl ethyl ketone as a solvent, with the total concentration of all components other than the solvent being 25% by mass. Note that the content of components other than methyl ethyl ketone shown herein is the content of the target product excluding the solvent.

[0229] <Manufacturing of support sheets> The support sheet was manufactured in the same manner as in Example 1, except that adhesive composition (R)-1 was used instead of adhesive composition (I)-1.

[0230] <<Evaluation of the support sheet>> The support sheets obtained above were evaluated using the same method as in Example 1. The results are shown in Table 1.

[0231] [Comparative Example 2] <<Manufacturing of support sheets>> <Manufacturing of energy-ray curable acrylic resin (Ia)> Energy-ray curable acrylic resin (Ia)-3 was obtained by adding MOI to acrylic polymer (2) and carrying out an addition reaction at 50°C for 48 hours in an air stream. The acrylic polymer (2) is a copolymer of 2EHA (35 parts by mass), 2EHMA (45 parts by mass), and HEA (20 parts by mass). The amount of MOI used was such that the total number of isocyanate groups in the MOI was 0.7 times the total number of hydroxyl groups derived from HEA in the acrylic polymer (2). The weight-average molecular weight of the obtained energy-ray curable acrylic resin (Ia)-3 was 880,000, and the glass transition temperature was -35°C.

[0232] <Manufacturing of adhesive compositions> An energy-ray-curable adhesive composition (R)-2 was prepared, containing energy-ray-curable acrylic resin (Ia)-3 (100 parts by mass), crosslinking agent (β)-1 (9.26 parts by mass), and photopolymerization initiator (γ)-1 (3 parts by mass), and further containing methyl ethyl ketone as a solvent, with the total concentration of all components other than the solvent being 25% by mass. Note that the content of components other than methyl ethyl ketone shown herein is the content of the target product excluding the solvent.

[0233] <Manufacturing of support sheets> The support sheet was manufactured in the same manner as in Example 1, except that adhesive composition (R)-2 was used instead of adhesive composition (I)-1.

[0234] <<Evaluation of the support sheet>> The support sheets obtained above were evaluated using the same method as in Example 1. The results are shown in Table 1.

[0235] [Comparative Example 3] <<Manufacturing of support sheets>> <Manufacturing of adhesive compositions> An energy-ray-curable adhesive composition (R)-3 was prepared, containing an energy-ray-curable acrylic resin (Ia)-3 (100 parts by mass), another energy-ray-curable compound (α')-1 (10 parts by mass), a crosslinking agent (β)-1 (9.26 parts by mass), and a photopolymerization initiator (γ)-1 (3 parts by mass), and further containing methyl ethyl ketone as a solvent, with the total concentration of all components other than the solvent being 25% by mass. Note that the content of all components other than methyl ethyl ketone shown herein is the content of the target product excluding the solvent.

[0236] <Manufacturing of support sheets> The support sheet was manufactured in the same manner as in Example 1, except that adhesive composition (R)-3 was used instead of adhesive composition (I)-1.

[0237] <<Evaluation of the support sheet>> The support sheets obtained above were evaluated using the same method as in Example 1. The results are shown in Table 1.

[0238] [Table 1]

[0239] As is clear from the results above, in Examples 1 to 4, the viscosity of the energy ray curable compound (α) at ​​23°C was 310 mPa·s or less, and the embedding ability of the adhesive layer on the matte surface of the substrate was high. As a result, in Examples 1 to 4, the average value of the light transmittance (400-800 nm) of the support sheet was 80.1% or higher, which is sufficiently high, and the chipping inspection accuracy of the support sheet was high. Furthermore, in Examples 1 to 4, the adhesive strength (X1) was 350 mN / 25 mm or less, and even after heating the support sheet with the silicon mirror wafer attached at 130°C for 2 hours, almost all of the silicon chips could be picked up normally, indicating high pick-up performance. In particular, in Examples 1 to 3, the adhesive strength (X1) was 200 mN / 25 mm or less, resulting in even higher pick-up performance. Thus, the support sheets of Examples 1 to 4 possessed the desired characteristics.

[0240] In Examples 1-4, the adhesive composition (I) contained an energy-ray curable acrylic resin (Ia) and an energy-ray curable compound (α), and it was presumed that the above-mentioned properties could be easily achieved. In particular, it was presumed that the above-mentioned properties could be easily achieved because the energy-ray curable compound (α) had a structure within a specific range.

[0241] Furthermore, in Examples 1 to 3, the adhesive strength (Y2) was 15,600 mN / 25 mm or more, which was sufficiently large, and even when the silicon wafer with the support sheet fixed to the ring frame was heated at a high temperature, the peeling of the silicon wafer with the support sheet from the ring frame was suppressed. Furthermore, in Examples 1 to 3, the adhesive force (X2) was 15,000 mN / 25 mm or more, which was sufficiently large. Even when large forces were applied to the silicon chips during processes such as dicing the silicon mirror wafer or washing the silicon chips with water after heating the silicon wafer with the support sheet at a high temperature, the peeling of the silicon chips from the support sheet was suppressed. Furthermore, in Examples 1 to 3, the adhesive force (X0) was 2900 mN / 25 mm or more, which is sufficiently large. It was therefore inferred that even when a significantly large force is applied to the silicon chip, such as during high-speed dicing of silicon mirror wafers or high-pressure water washing of silicon chips after dicing, peeling of the silicon chip from the support sheet can be suppressed.

[0242] In particular, in Examples 1 and 2, the adhesive strength (Y1) was remarkably high, at 470 mN / 25 mm or more. It was hypothesized that even if the support sheets in Examples 1 and 2 were to be fixed to the ring frame in the state of the silicon wafer with the support sheet attached and heated, and even if energy rays were irradiated onto the contact portion of the support sheet (adhesive layer) with the ring frame, the peeling of the cured support sheet-attached silicon chip group from the ring frame could be suppressed.

[0243] Thus, the support sheets of Examples 1-3 were preferable because they also exhibited superior properties beyond the intended purpose.

[0244] In contrast, Comparative Examples 1 and 2 did not use the energy-ray curable compound (α), resulting in poor embedding of the adhesive layer on the matte surface of the substrate. As a result, the average light transmittance (400-800 nm) of the support sheets in Comparative Examples 1 and 2 was 79.1% or less, which was insufficient, and the chipping inspection accuracy of the support sheets was low. The support sheets in Comparative Examples 1 and 2 did not possess the desired properties. In addition, in Comparative Example 2, the adhesive strength (X1) was high, and after heating the support sheet with the silicon mirror wafer attached at 130°C for 2 hours, the silicon chip could not be picked up properly, indicating poor pick-up performance.

[0245] Furthermore, in Comparative Example 1, both the adhesive strength (Y1) and adhesive strength (Y2) were insufficient, and it was inferred that this support sheet was insufficient in suppressing peeling from the ring frame, regardless of whether it was a silicon wafer with the support sheet attached or a group of silicon chips with a cured support sheet attached. Furthermore, in Comparative Example 2, the adhesive strength (X2) was low, and it was inferred that the effect of suppressing the peeling of the silicon chip from the support sheet was low when a large force was applied to the silicon chip after heating the silicon wafer with the support sheet at a high temperature, such as during dicing of the silicon mirror wafer or washing of the silicon chip after dicing.

[0246] In Comparative Example 3, the adhesive composition (I) contained another energy-ray-curable compound (α') instead of the energy-ray-curable compound (α), and its viscosity at 23°C was high at 360 mPa·s. As a result, the embedding ability of the adhesive layer on the matte surface of the substrate was poor, even worse than in Comparative Examples 1 and 2. Consequently, the average light transmittance (400-800 nm) of the support sheet in Comparative Example 3 was even lower than in Comparative Examples 1 and 2. In addition, the adhesive strength (X1) in Comparative Example 3 was high, even greater than that in Comparative Example 2. Thus, the support sheet of Comparative Example 3 was even inferior to the support sheets of Comparative Examples 1 and 2 in terms of characteristics, and therefore no further evaluation was performed on Comparative Example 3. [Industrial applicability]

[0247] This invention can be used in the manufacturing of workpieces such as semiconductor chips. [Explanation of Symbols]

[0248] 1...Support sheet, 11...Substrate, 11a...One side of the substrate, 12...Adhesive layer, 12'...Energy ray cured product, 8...Ring frame, 9...Semiconductor wafer, 90...Semiconductor chip, 109...Semiconductor wafer with support sheet

Claims

1. It is a support sheet, The support sheet comprises a base material and an adhesive layer provided on one surface of the base material. One of the aforementioned surfaces is a matte surface, The adhesive layer contains an energy-ray curable compound and is energy-ray curable. The viscosity of the energy ray curable compound at 23°C is 350 mPa·s or less. The support sheet is attached to the mirror surface of the silicon mirror wafer by the adhesive layer, the adhesive layer is heated to 130°C after attachment, the heated adhesive layer is energy-ray cured, and the adhesive force (X1) between the energy-ray cured adhesive layer and the silicon mirror wafer is measured, and the adhesive force (X1) is 400 mN / 25 mm or less. A support sheet wherein the support sheet is attached to the mirror surface of a silicon mirror wafer by the adhesive layer, the adhesive layer is heated to 130°C after attachment, and the adhesive force (X2) between the heated adhesive layer and the silicon mirror wafer is measured, and the adhesive force (X2) is 13,000 mN / 25 mm or more.

2. The support sheet according to claim 1, wherein the adhesive layer further contains an energy-ray curable acrylic resin.

3. The support sheet according to claim 1 or 2, wherein the support sheet is attached to the surface of a stainless steel plate by the adhesive layer, the adhesive layer is heated to 130°C after attachment, and the adhesive force (Y2) between the heated adhesive layer and the stainless steel plate is measured, and the adhesive force (Y2) is 13,000 mN / 25 mm or more.

4. The support sheet according to any one of claims 1 to 3, wherein the support sheet is attached to the surface of a stainless steel plate by the adhesive layer, the adhesive layer is heated to 130°C after attachment, the adhesive layer is energy-ray cured after heating, and the adhesive force (Y1) between the energy-ray cured product of the adhesive layer and the stainless steel plate is measured, and the adhesive force (Y1) is 300 mN / 25 mm or more.

5. The support sheet according to any one of claims 1 to 4, wherein the average value of the light transmittance of the support sheet in the wavelength range of 400 to 800 nm is 80% or more.

6. A method for manufacturing a workpiece, The manufacturing method includes a bonding step of fixing a workpiece with a support sheet, which comprises the workpiece and the support sheet provided on the workpiece, to the ring frame by bonding the adhesive layer in the support sheet according to any one of claims 1 to 5 to the workpiece and the ring frame, After the aforementioned bonding step, a heating step is performed to heat the adhesive layer in the support sheet fixed to the ring frame, After the aforementioned bonding step, a processing step is performed to produce the workpiece by processing the workpiece in the workpiece with the support sheet fixed to the ring frame, After the heating step and processing step, a curing step is performed in which the adhesive layer attached to the ring frame is cured by energy rays. A method for manufacturing a workpiece, comprising a pick-up step after the curing step, in which the workpiece is pulled away from the cured product of the adhesive layer and picked up.

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