Adhesive sheet and method for producing adhesive sheet

Abstract

The present invention provides an adhesive sheet (1A) having a substrate (10) and an adhesive layer (20). The adhesive layer (20) containing an energy ray curable resin has a cured portion (22) formed by curing the energy ray curable resin at both ends in the width direction and an uncured portion (21). The tensile strength F A1 and the tensile strength F B1 satisfy the relationship of the following mathematical formula (Mathematical formula 1A), F B1 / F A1 ≤ 30 ··· (Mathematical formula 1A). The tensile strength F A1 is: the tensile strength when a first test piece with a width of 25 mm is made from the region corresponding to the uncured portion (21), and the two ends in the length direction of the first test piece are clamped with a jig and stretched by 0.5 mm using a tensile testing machine; the tensile strength F B1 is: the tensile strength when a second test piece is made, and the two ends in the length direction of the second test piece are clamped with a jig and stretched by 0.5 mm using a tensile testing machine. The second test piece is made by bonding a first semiconductor chip on one end side in the length direction of the first test piece and bonding a second semiconductor chip on the other end side in the length direction in a first semiconductor chip and a second semiconductor chip having a longitudinal dimension of 45 mm, a transverse dimension of 35 mm, and a thickness dimension of 0.625 mm.

Description

Technical Field

[0001] The present invention relates to an adhesive sheet and a method for producing the adhesive sheet. Background Art

[0002] In recent years, the miniaturization, lightness and high functionality of electronic devices have been continuously developed. The semiconductor devices carried by electronic devices are also required to be miniaturized, thinned and high-density. Semiconductor chips are sometimes installed in packages close to their size. Such packages are sometimes also called chip scale packages (CSP). As one of the CSPs, wafer level packages (WLP) can be cited. In WLP, external electrodes are formed on the wafer before singulation by cutting, and the wafer is finally cut for singulation. As WLP, fan-in (Fan-In) type and fan-out (Fan-Out) type can be cited. In the fan-out type WLP (hereinafter, sometimes referred to as "FO-WLP"), the semiconductor chip is covered with a sealing material to form an area larger than the chip size to form a semiconductor chip sealed body, and a rewiring layer and external electrodes are formed not only on the circuit surface of the semiconductor chip, but also on the surface area of ​​the sealing material.

[0003] For example, Patent Document 1 describes a method for manufacturing a semiconductor package, which includes: for a plurality of semiconductor chips formed by singulation of a semiconductor wafer, retaining their circuit forming surfaces, surrounding them with a mold member to form an expanded wafer, and extending the rewiring pattern to an area outside the semiconductor chip to form a semiconductor package. In the manufacturing method described in Patent Document 1, before surrounding the plurality of semiconductor chips formed by singulation with the mold member, a wafer mount tape for expansion is alternately attached, and the wafer mount tape for expansion is extended to expand the distance between the plurality of semiconductor chips.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2010 / 058646 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the sheet expansion step, the tape or sheet on which the plurality of semiconductor chips are bonded is stretched to expand the intervals between the semiconductor chips. When the sheet is stretched by pulling, if the amount of elongation in the sheet surface is different, it is difficult to expand the intervals between the semiconductor chips uniformly.

[0009] In addition, there may be a problem in which the adhesive contained in the adhesive layer of the adhesive sheet oozes out from the end portions in the width direction of the sheet.

[0010] An object of the present invention is to provide an adhesive sheet having excellent expandability and capable of reducing the difference in the amount of elongation of the adhesive sheet in the in-plane direction when the adhesive sheet is stretched in a sheet expansion step to expand the distance between semiconductor chips.

[0011] Another object of the present invention is to provide an adhesive sheet having excellent expandability and capable of suppressing the seepage of the adhesive and reducing the difference in the elongation of the adhesive sheet in the in-plane direction when the adhesive sheet is stretched in the sheet expansion process to expand the distance between semiconductor chips, and a method for manufacturing the adhesive sheet.

[0012] Solutions to the problem

[0013] A pressure-sensitive adhesive sheet according to one embodiment of the present invention comprises a substrate and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive sheet has a tensile strength F A1 and tensile strength F B1 The relationship satisfying the following mathematical formula (Mathematical formula 1A) is:

[0014] F B1 / F A1 ≤30···(Mathematical formula 1A)

[0015] The tensile strength F A1 The first test piece with a width of 25 mm is prepared from the adhesive sheet, the substrate and the adhesive layer at both ends of the first test piece in the longitudinal direction are clamped with a clamp, and the tensile strength is measured by a tensile tester when stretched by 0.5 mm.

[0016] The tensile strength F B1 The method comprises the following steps: making a second test piece, clamping a substrate, an adhesive layer and a semiconductor chip at both ends of the second test piece in the longitudinal direction with a clamp, and measuring the tensile strength when stretched by 0.5 mm using a tensile testing machine. The second test piece is made by making the first semiconductor chip with a longitudinal dimension of 45 mm, a transverse dimension of 35 mm and a thickness dimension of 0.625 mm and the longitudinal dimension of the second semiconductor chip with an edge of 45 mm along the longitudinal direction of the first test piece, setting the interval between the first semiconductor chip and the second semiconductor chip to 35 μm, bonding the first semiconductor chip to the adhesive layer at one end of the first test piece in the longitudinal direction, and bonding the second semiconductor chip to the adhesive layer at the other end of the first test piece in the longitudinal direction.

[0017] A pressure-sensitive adhesive sheet according to one embodiment of the present invention comprises a substrate and a pressure-sensitive adhesive layer.

[0018] The adhesive layer contains an energy-ray-curable resin.

[0019] The adhesive layer comprises cured portions at both ends in the width direction of the adhesive layer where the energy-ray curable resin is cured, and uncured portions where the energy-ray curable resin is not cured.

[0020] The tensile strength F of the above adhesive sheet A1 and tensile strength F B1 The relationship satisfying the following mathematical formula (Mathematical formula 1A) is:

[0021] F B1 / F A1 ≤30···(Mathematical formula 1A)

[0022] The tensile strength F A1 The first test piece with a width of 25 mm was prepared from the adhesive sheet in the area corresponding to the uncured portion, and the substrate and the uncured portion of the adhesive layer at both ends of the first test piece in the longitudinal direction were clamped with a clamp, and the tensile strength was measured by a tensile tester when stretched by 0.5 mm.

[0023] The tensile strength F B1 The method comprises the following steps: preparing a second test piece, clamping a substrate, an adhesive layer of an uncured portion and a semiconductor chip at both ends of the second test piece in the longitudinal direction with a clamp, and measuring the tensile strength when stretched by 0.5 mm using a tensile testing machine. The second test piece is prepared by making the first semiconductor chip having a longitudinal dimension of 45 mm, a transverse dimension of 35 mm and a thickness dimension of 0.625 mm and the longitudinal dimension of 45 mm of the second semiconductor chip along the longitudinal direction of the first test piece, setting the interval between the first semiconductor chip and the second semiconductor chip to 35 μm, bonding the first semiconductor chip to the adhesive layer of the uncured portion at one end side in the longitudinal direction of the first test piece, and bonding the second semiconductor chip to the adhesive layer of the uncured portion at the other end side in the longitudinal direction of the first test piece.

[0024] In an adhesive sheet of one embodiment of the present invention, a third test piece is prepared by cutting a piece having a length of 150 mm and a width of 25 mm along the length direction of the adhesive sheet in a manner that includes a cured portion formed by curing the energy-ray-curing resin. The third test piece is clamped by a pair of chucks with a distance between the chucks set to 100 mm, and when it is stretched at a speed of 5 mm / sec until the distance between the chucks reaches 200 mm, preferably, no warping occurs at the interface between the cured portion and the substrate.

[0025] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention,

[0026] The above-mentioned adhesive sheet is stretched along a first direction, a second direction opposite to the first direction, a third direction perpendicular to the first direction, and a fourth direction opposite to the third direction. When the area ratio (S2 / S1)×100 of the area S1 of the above-mentioned adhesive sheet before stretching and the area S2 of the above-mentioned adhesive sheet after stretching is 381%, it is preferred that the above-mentioned cured portion of the above-mentioned adhesive layer does not peel off at the interface with the above-mentioned substrate.

[0027] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the tensile strength F A1 And the above tensile strength F B1 The relationship of the following mathematical formula (Mathematical formula 1B) is satisfied.

[0028] 1≤F B1 / F A1 ≤30···(Mathematical formula 1B)

[0029] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, it is preferred that the Young's modulus Y of the first test piece is A1 and the Young's modulus Y of the second test piece B1 The relationship of the following mathematical formula (Mathematical formula 2A) is satisfied.

[0030] Y B1 / Y A1 ≤19···(Mathematical formula 2A)

[0031] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the pressure-sensitive adhesive layer preferably contains an acrylic pressure-sensitive adhesive.

[0032] In the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the substrate preferably contains a urethane elastomer.

[0033] The adhesive sheet according to one embodiment of the present invention is preferably used in a chip expanding step for expanding the interval between a plurality of semiconductor chips in a semiconductor device manufacturing step.

[0034] The pressure-sensitive adhesive sheet according to one embodiment of the present invention is in a long strip shape and is wound into a roll shape.

[0035] A method for producing a pressure-sensitive adhesive sheet according to one embodiment of the present invention comprises:

[0036] A step of applying an adhesive composition containing an energy-ray-curable resin on a substrate to form an adhesive layer;

[0037] a step of irradiating both ends of the adhesive layer in the width direction with energy rays to cure the energy ray-curable resin to form a cured portion; and

[0038] A step of leaving all or part of the cured portion outside both ends in the width direction of the uncured portion where the energy ray curable resin is not cured, and cutting the outside of the cured portion.

[0039] In the method for producing a pressure-sensitive adhesive sheet according to one embodiment of the present invention,

[0040] It is preferred that the width of each of the cured portions remaining outside both end portions in the width direction of the uncured portion is independently 0.5 mm or more.

[0041] In the method for producing a pressure-sensitive adhesive sheet according to one embodiment of the present invention,

[0042] After the step of cutting the outer side of the cured portion, there is further provided a step of winding the cut pressure-sensitive adhesive sheet into a roll.

[0043] According to one embodiment of the present invention, it is possible to provide an adhesive sheet having excellent expandability and capable of reducing the difference in the amount of extension of the adhesive sheet in the in-plane direction when the adhesive sheet is stretched in the sheet expansion step to expand the distance between semiconductor chips.

[0044] According to another embodiment of the present invention, there can be provided an adhesive sheet having excellent expandability and capable of suppressing the seepage of the adhesive and reducing the difference in the elongation of the adhesive sheet in the in-plane direction when the adhesive sheet is stretched to expand the distance between semiconductor chips in the sheet expansion process, and a method for manufacturing the adhesive sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment.

[0046] Figure 2 It is a schematic diagram showing a state where the first test piece is clamped by the clamps of the tensile testing machine.

[0047] Figure 3 It is a schematic diagram showing a state where the second test piece is clamped by the clamps of the tensile testing machine.

[0048] Figure 4 It is a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment.

[0049] Figure 5 This is a perspective view showing a state where a pressure-sensitive adhesive sheet according to another embodiment is wound into a roll.

[0050] Fig. 6A This is a schematic cross-sectional view showing a method for producing a pressure-sensitive adhesive sheet according to another embodiment.

[0051] Figure 6B This is a schematic cross-sectional view showing a method for producing a pressure-sensitive adhesive sheet according to another embodiment.

[0052] Figure 6C This is a schematic cross-sectional view showing a method for producing a pressure-sensitive adhesive sheet according to another embodiment.

[0053] Figure 7 This is a plan view for explaining a biaxially stretched sheet expanding device used in the examples.

[0054] Explanation of symbols

[0055] 1 ... adhesive sheet, 10 ... substrate, 20 ... adhesive layer, CP1 ... first semiconductor chip, CP2 ... second semiconductor chip. DETAILED DESCRIPTION

[0056] Hereinafter, one embodiment of the present invention will be described.

[0057] [First embodiment]

[0058] [Adhesive sheet]

[0059] The adhesive sheet of this embodiment has a substrate and an adhesive layer. The shape of the adhesive sheet can be any shape, such as a tape (long strip form) or a label (sheet form).

[0060] Figure 1 This is a schematic cross-sectional view of an example of the pressure-sensitive adhesive sheet according to the present embodiment. Figure 1 4 discloses a pressure-sensitive adhesive sheet 1 including a substrate 10 and a pressure-sensitive adhesive layer 20 .

[0061] In the PSA sheet of the present embodiment, the ratio of the tensile strengths measured by a tensile testing machine on a first test piece and a second test piece prepared from the PSA sheet satisfies a given range.

[0062] (First test piece)

[0063] The first test piece was produced from the pressure-sensitive adhesive sheet of this embodiment. The width of the first test piece was 25 mm.

[0064] Figure 2 The diagram schematically shows a state where the substrate 10 and the adhesive layer 20 at one end of the first test piece are clamped by the first clamp 110 of the tensile tester, and the substrate 10 and the adhesive layer 20 at the other end of the first test piece are clamped by the second clamp 120 of the tensile tester.

[0065] (Second test piece)

[0066] The second test piece is made by attaching two semiconductor chips to the first test piece made of the adhesive sheet of this embodiment. In this embodiment, the two semiconductor chips are the first semiconductor chip and the second semiconductor chip. The dimensions of the first semiconductor chip and the second semiconductor chip are both 45 mm in longitudinal dimension, 35 mm in transverse dimension, and 0.625 mm in thickness.

[0067] The first semiconductor chip and the second semiconductor chip were bonded together so that the sides having a vertical dimension of 45 mm were aligned with the longitudinal direction of the first test piece.

[0068] The first semiconductor chip is attached to one end of the first test piece in the longitudinal direction. The second semiconductor chip is attached to the other end of the first test piece in the longitudinal direction. The interval between the first semiconductor chip and the second semiconductor chip attached to the first test piece is set to 35 μm,

[0069] Figure 3 It is a schematic diagram showing a state in which the substrate 10, the adhesive layer 20 and the first semiconductor chip CP1 on one end side of the second test piece are clamped by the first clamp 110 of the tensile testing machine, and the substrate 10, the adhesive layer 20 and the second semiconductor chip CP2 on the other end side of the second test piece are clamped by the second clamp 120 of the tensile testing machine.

[0070] (Tensile Strength)

[0071] In the pressure-sensitive adhesive sheet of the present embodiment, the tensile strengths of the first test piece and the second test piece measured using a tensile tester satisfy the relationship of the following mathematical formula (Mathematical Formula 1A).

[0072] F B1 / F A1 ≤30···(Mathematical formula 1A)

[0073] In the above formula (Formula 1A), the tensile strength F A1 This is the strength when the substrate and the adhesive layer at each end in the longitudinal direction of the first test piece are clamped with a clamp and stretched by 0.5 mm using a tensile tester.

[0074] In the above formula (Formula 1A), the tensile strength F B1 This is the strength when the substrate, the adhesive layer and the semiconductor chip at both ends of the second test piece in the longitudinal direction are clamped with a clamp and stretched by 0.5 mm using a tensile tester.

[0075] The inventors of the present invention have found that when the adhesive sheet is expanded (extended) at a portion where the semiconductor chip is not bonded and at a portion where the semiconductor chip is bonded, the behavior of the adhesive sheet in the extension mode is different. In addition, the inventors of the present invention have also found that in the existing adhesive sheet, the tensile strength of the portion where the semiconductor chip is not bonded is greatly different from the tensile strength of the portion where the semiconductor chip is bonded, and when the adhesive sheet is extended in the expansion process to increase the distance between the semiconductor chips, the difference in the elongation of the adhesive sheet in the in-plane direction is large.

[0076] According to the PSA sheet of this embodiment, F B1 / F A1 The ratio of the tensile strength of the adhesive sheet where the semiconductor chip is not bonded to the tensile strength of the adhesive sheet where the semiconductor chip is bonded is 30 or less. B1 / F A1 Therefore, according to the adhesive sheet of this embodiment, when the adhesive sheet is stretched in the sheet expansion step to expand the distance between the semiconductor chips, the difference in the elongation of the adhesive sheet in the in-plane direction is reduced, the expandability is excellent, and the non-uniformity of the distance between the semiconductor chips can be reduced.

[0077] It should be noted that the tensile strength F A1 and F B1 The stretching amount of 0.5 mm during the stretching is a rough standard for the stretching amount in the sheet expansion process. Therefore, the adhesive sheet of this embodiment can be used in the sheet expansion process with a stretching amount less than 0.5 mm, and can also be used in the sheet expansion process with a stretching amount greater than 0.5 mm.

[0078] According to the PSA sheet of this embodiment, due to the F B1 / F A1 Therefore, when the adhesive sheet of this embodiment is used in a sheet expansion step in which the sheet is stretched to a length greater than 0.5 mm, the difference in elongation in tensile strength between the portion of the adhesive sheet where the semiconductor chip is not bonded and the portion where the semiconductor chip is bonded can be prevented from becoming excessively large.

[0079] In the pressure-sensitive adhesive sheet of the present embodiment, the tensile strength F of the first test piece measured using a tensile testing machine is preferably A1 and the tensile strength F of the second test piece B1 The relationship of the following mathematical formula (Mathematical formula 1B) is satisfied.

[0080] 1≤F B1 / F A1 ≤30···(Mathematical formula 1B)

[0081] In the pressure-sensitive adhesive sheet of the present embodiment, the tensile strength F of the first test piece measured using a tensile testing machine is preferably A1 and the tensile strength F of the second test pieceB1 The relationship of the following mathematical formula (Mathematical formula 1C) is also satisfied.

[0082] F B1 / F A1 ≤20···(Mathematical formula 1C)

[0083] As F B1 / F A1 The method for adjusting the value of to be within the range of the above-mentioned mathematical formula (Mathematical formula 1A), mathematical formula (Mathematical formula 1B) or mathematical formula (Mathematical formula 1C) can be exemplified by the following method. For example, F can be adjusted by one of the following methods or by combining two or more of the following methods. B1 / F A1 The value of is adjusted to be within the range of the above-mentioned mathematical formula (Mathematical Formula 1A), mathematical formula (Mathematical Formula 1B) or mathematical formula (Mathematical Formula 1C), and the method is to change the composition of the adhesive composition used in the adhesive layer 20, change the thickness of the adhesive layer, change the material of the substrate, and change the thickness of the substrate.

[0084] (Young's modulus)

[0085] In the pressure-sensitive adhesive sheet of the present embodiment, the Young's modulus Y of the first test piece is preferably A1 and Young's modulus Y of the second test piece B1 The relationship of the following mathematical formula (Mathematical formula 2A) is satisfied.

[0086] Y B1 / Y A1 ≤19···(Mathematical formula 2A)

[0087] By satisfying the relationship of the above formula (Formula 2A), the ratio Y of the Young's modulus of the portion of the adhesive sheet where the semiconductor chip is not bonded to the Young's modulus of the portion where the semiconductor chip is bonded is B1 / Y A1 Therefore, when the adhesive sheet is extended in the expansion process to expand the distance between the semiconductor chips, it is easy to reduce the difference in the elongation of the adhesive sheet in the in-plane direction. In addition, by satisfying the relationship of the above mathematical formula (Mathematical Formula 2A), even if the adhesive sheet is used in the expansion process with a stretching amount greater than 0.5 mm, Y can be suppressed. B1 / Y A1 becomes too large.

[0088] The Young's modulus of the pressure-sensitive adhesive sheet can be measured by the measurement method described in the Examples described below.

[0089] (Base material)

[0090] Preferably, the substrate has a first substrate surface and a second substrate surface opposite to the first substrate surface. Figure 1As shown, the substrate 10 of the pressure-sensitive adhesive sheet 1 has a first substrate surface 11 and a second substrate surface 12 opposite to the first substrate surface 11 .

[0091] In the pressure-sensitive adhesive sheet of the present embodiment, the pressure-sensitive adhesive layer of the present embodiment is preferably provided on one of the first substrate surface and the second substrate surface.

[0092] From the viewpoint of being easily stretched to a large extent, the material of the substrate is preferably a thermoplastic elastomer or a rubber-based material, and more preferably a thermoplastic elastomer.

[0093] As thermoplastic elastomers, there can be cited: carbamate elastomers, olefin elastomers, vinyl chloride elastomers, polyester elastomers, styrene elastomers, acrylic elastomers, and amide elastomers. One thermoplastic elastomer can be used alone, or two or more can be used in combination. As a thermoplastic elastomer, from the viewpoint of being easy to stretch significantly, a carbamate elastomer is preferably used. That is, in the adhesive sheet of the present embodiment, it is preferred that the substrate contains a carbamate elastomer.

[0094] The substrate may be a laminated film formed by laminating a plurality of films formed of the above-mentioned materials (e.g., thermoplastic elastomers or rubber-like materials). Alternatively, the substrate may be a laminated film formed by laminating a film formed of the above-mentioned materials (e.g., thermoplastic elastomers or rubber-like materials) with other films.

[0095] The base material may contain additives in a film having the above-mentioned resin material as a main material.

[0096] Examples of additives include pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, and fillers. Examples of pigments include titanium dioxide and carbon black. In addition, examples of fillers include organic materials such as melamine resins, inorganic materials such as fumed silica, and metal materials such as nickel particles. The content of such additives is not particularly limited, but preferably falls within a range that enables the substrate to perform the desired function.

[0097] For substrate, in order to improve the adhesion of the adhesive layer stacked on at least any one of the first substrate surface and the second substrate surface, surface treatment or primer treatment can be implemented on one side or both sides as needed. As surface treatment, oxidation method and concavoconvex method can be cited. As primer treatment, a method for forming a primer layer on the substrate surface can be cited. As oxidation method, for example: corona discharge treatment, plasma discharge treatment, chromating treatment (wet), flame treatment, hot air treatment, ozone treatment, and ultraviolet irradiation treatment can be cited. As concavoconvex method, for example, sandblasting and spray treatment can be cited.

[0098] When the adhesive layer contains an energy-ray-curable adhesive, the substrate preferably has transmissivity to the energy ray. When ultraviolet rays are used as the energy ray, the substrate preferably has transmissivity to the ultraviolet rays. When electron beams are used as the energy ray, the substrate preferably has transmissivity to electron beams.

[0099] The thickness of the substrate is not limited as long as the adhesive sheet can properly function in the desired process. The thickness of the substrate is preferably 20 μm or more, more preferably 40 μm or more. In addition, the thickness of the substrate is preferably 250 μm or less, more preferably 200 μm or less.

[0100] In addition, when the thickness of multiple locations is measured at 2 cm intervals in the in-plane direction of the first substrate surface or the second substrate surface of the substrate, the standard deviation of the thickness of the substrate is preferably 2 μm or less, more preferably 1.5 μm or less, and further preferably 1 μm or less. By making the standard deviation 2 μm or less, the adhesive sheet has a high-precision thickness and can be stretched uniformly.

[0101] At 23°C, the tensile elastic modulus of the substrate in the MD and CD directions is 10 MPa to 350 MPa, respectively, and the 100% stress of the substrate in the MD and CD directions is 3 MPa to 20 MPa, respectively.

[0102] By setting the tensile elastic modulus and 100% stress within the above ranges, the PSA sheet can be stretched to a large extent.

[0103] The 100% stress of the substrate is a value obtained as follows. A test piece of 100 mm (length direction) × 15 mm (width direction) is cut from the substrate. The two ends of the cut test piece in the length direction are clamped with a clamp so that the length between the clamps is 50 mm. After clamping the test piece with the clamp, it is stretched in the length direction at a speed of 200 mm / min, and the measured value of the tensile force is read when the length between the clamps reaches 100 mm. The 100% stress of the substrate is the value obtained by dividing the measured value of the tensile force read by the cross-sectional area of ​​the substrate. The cross-sectional area of ​​the substrate is calculated according to the width length 15 mm × the thickness of the substrate (test piece). The cutting is performed in a manner that the travel direction (MD direction) or the direction perpendicular to the MD direction (CD direction) when the substrate is manufactured is consistent with the length direction of the test piece. It should be noted that in this tensile test, the thickness of the test piece is not particularly limited and can be the same as the thickness of the substrate as the test object.

[0104] At 23° C., the elongations at break of the substrate in the MD direction and the CD direction are preferably 100% or more, respectively.

[0105] When the elongations at break of the substrate in the MD direction and the CD direction are each 100% or more, the PSA sheet can be stretched to a large extent without breaking.

[0106] The tensile modulus of elasticity (MPa) of the substrate and the elongation at break (%) of the substrate can be measured as described below. The substrate is cut into 15mm×140mm to obtain a test piece. For the test piece, the elongation at break and the tensile modulus at 23°C are measured according to JIS K7161:2014 and JIS K7127:1999. Specifically, for the above-mentioned test piece, a tensile testing machine (manufactured by Shimadzu Corporation, product name "Autograph AG-IS 500N") is used, the distance between the chucks is set to 100mm, and then a tensile test is performed at a speed of 200mm / min to measure the elongation at break (%) and the tensile modulus (MPa). It should be noted that the measurement is carried out in two directions: the direction of travel (MD) when the substrate is manufactured and the direction (CD) at right angles thereto.

[0107] (Adhesive layer)

[0108] In the adhesive sheet of the present embodiment, the adhesive layer is not particularly limited as long as it satisfies the relationship of the above-mentioned mathematical formula (Mathematical Formula 1A). In order to satisfy the range of the relationship of the above-mentioned mathematical formula (Mathematical Formula 1A), for example, the material constituting the adhesive layer can be appropriately selected from the materials described below for combination.

[0109] For example, examples of the adhesive used for the adhesive layer include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, polyester-based adhesives, and urethane-based adhesives.

[0110] In the pressure-sensitive adhesive sheet of the present embodiment, the pressure-sensitive adhesive layer preferably contains an acrylic pressure-sensitive adhesive.

[0111] Energy ray curable resin (a1)

[0112] The pressure-sensitive adhesive layer preferably contains an energy-ray curable resin (a1). The energy-ray curable resin (a1) has an energy-ray curable double bond in the molecule.

[0113] The adhesive layer containing the energy-ray curable resin is cured by energy-ray irradiation, and the adhesive force is reduced. When it is desired to separate the adherend from the adhesive sheet, the adhesive layer can be easily separated by irradiating the adhesive layer with energy rays.

[0114] The energy beam curable resin (a1) is preferably a (meth)acrylic resin.

[0115] The energy ray curable resin (a1) is preferably an ultraviolet curable resin, and more preferably an ultraviolet curable (meth)acrylic resin.

[0116] The energy-ray-curable resin (a1) is a resin that is polymerized and cured when irradiated with energy rays. Examples of the energy rays include ultraviolet rays and electron beams.

[0117] As examples of energy-ray curable resins (a1), low molecular weight compounds (monofunctional monomers, polyfunctional monomers, monofunctional oligomers, and polyfunctional oligomers) having energy-ray polymerizable groups can be cited. Specifically, energy-ray curable resins (a1) can use acrylates such as trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, dipentaerythritol monohydroxy pentaacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, acrylates containing cyclic aliphatic skeletons such as dicyclopentadiene dimethoxy diacrylate and isobornyl acrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomers, epoxy-modified acrylates, polyether acrylates, itaconic acid oligomers, and other acrylate compounds.

[0118] The molecular weight of the energy beam curable resin (a1) is generally about 100 or more and 30,000 or less, and preferably about 300 or more and 10,000 or less.

[0119] ·(Meth)acrylic acid copolymer (b1)

[0120] The pressure-sensitive adhesive layer of the present embodiment preferably further contains a (meth)acrylic copolymer (b1). The (meth)acrylic copolymer is different from the energy-beam curable resin (a1) described above.

[0121] The (meth)acrylic copolymer (b1) preferably has an energy-ray-curable carbon-carbon double bond. That is, in the present embodiment, the pressure-sensitive adhesive layer preferably contains the energy-ray-curable resin (a1) and the energy-ray-curable (meth)acrylic copolymer (b1).

[0122] The pressure-sensitive adhesive layer of the present embodiment preferably contains 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 25 parts by mass or more of the energy-ray curable resin (a1) based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0123] The pressure-sensitive adhesive layer of the present embodiment preferably contains 80 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less of the energy-ray curable resin (a1) based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0124] The weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more.

[0125] The weight average molecular weight (Mw) of the (meth)acrylic copolymer (b1) is preferably 1.5 million or less, and more preferably 1 million or less.

[0126] In addition, the weight average molecular weight (Mw) in this specification is a value converted into standard polystyrene measured by gel permeation chromatography (GPC method).

[0127] The (meth)acrylic copolymer (b1) is preferably a (meth)acrylate polymer (b2) having an energy-ray-curable functional group (energy-ray-curable group) introduced into a side chain (hereinafter sometimes referred to as “energy-ray-curable polymer (b2)”).

[0128] The energy-ray-curable polymer (b2) is preferably a copolymer obtained by reacting an acrylic copolymer (b21) having a monomer unit containing a functional group with an unsaturated group-containing compound (b22) having a functional group bonded to the functional group. It should be noted that in this specification, (meth)acrylate refers to both acrylate and methacrylate. The same applies to other similar terms.

[0129] The acrylic copolymer (b21) preferably includes a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth)acrylic acid ester monomer or a (meth)acrylic acid ester monomer derivative.

[0130] The functional group-containing monomer as a structural unit of the acrylic copolymer (b21) is preferably a monomer having a polymerizable double bond and a functional group in the molecule. The functional group is preferably at least one functional group selected from hydroxyl, carboxyl, amino, substituted amino, and epoxy groups.

[0131] Examples of the hydroxyl-containing monomer include 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. The hydroxyl-containing monomer may be used alone or in combination of two or more.

[0132] Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. The carboxyl group-containing monomer may be used alone or in combination of two or more.

[0133] Examples of the amino group-containing monomer or substituted amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. The amino group-containing monomer or substituted amino group-containing monomer may be used alone or in combination of two or more.

[0134] As the (meth)acrylate monomer constituting the acrylic copolymer (b21), in addition to (meth)acrylate alkyl esters having an alkyl group carbon number of 1 to 20, for example, monomers having an alicyclic structure in the molecule (alicyclic structure-containing monomers) can be preferably used.

[0135] As the alkyl (meth)acrylate, an alkyl (meth)acrylate having an alkyl carbon number of 1 to 18 is preferred. More preferred alkyl (meth)acrylates include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The alkyl (meth)acrylate may be used alone or in combination of two or more.

[0136] As the alicyclic structure-containing monomer, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate can be preferably used. The alicyclic structure-containing monomer can be used alone or in combination of two or more.

[0137] The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a ratio of 1% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more.

[0138] The acrylic copolymer (b21) preferably contains the structural unit derived from the functional group-containing monomer in a ratio of 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0139] The acrylic copolymer (b21) preferably contains 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, of a structural unit derived from a (meth)acrylate monomer or a derivative thereof.

[0140] The acrylic copolymer (b21) preferably contains a structural unit derived from a (meth)acrylate monomer or a derivative thereof in a ratio of 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0141] The acrylic copolymer (b21) can be obtained by copolymerizing the above-mentioned functional group-containing monomer and a (meth)acrylic acid ester monomer or a derivative thereof by a common method.

[0142] The acrylic copolymer (b21) may contain at least one structural unit selected from dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like in addition to the above-mentioned monomers.

[0143] The energy ray-curable polymer (b2) can be obtained by reacting the acrylic copolymer (b21) having the above-mentioned functional group-containing monomer unit with the unsaturated group-containing compound (b22) having a functional group bonded to the functional group thereof.

[0144] The functional group of the unsaturated group-containing compound (b22) can be appropriately selected according to the type of functional group of the functional group-containing monomer unit of the acrylic copolymer (b21). For example, when the functional group of the acrylic copolymer (b21) is hydroxyl, amino or substituted amino, the functional group of the unsaturated group-containing compound (b22) is preferably an isocyanate group or an epoxy group, and when the functional group of the acrylic copolymer (b21) is an epoxy group, the functional group of the unsaturated group-containing compound (b22) is preferably an amino, carboxyl or aziridine group.

[0145] The unsaturated group-containing compound (b22) contains at least one energy-ray-polymerizable carbon-carbon double bond in one molecule, preferably one or more and six or less, and more preferably one or more and four or less.

[0146] Examples of the unsaturated group-containing compound (b22) include: 2-methacryloyloxyethyl isocyanate (2-isocyanatoethyl methacrylate), m-isopropenyl-α,α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or a polyisocyanate compound with hydroxyethyl (meth)acrylate; acryloyl monoisocyanate compounds obtained by the reaction of a diisocyanate compound or a polyisocyanate compound, a polyol compound, and hydroxyethyl (meth)acrylate; glycidyl (meth)acrylate; (meth)acrylic acid, 2-(1-aziridinyl)ethyl (meth)acrylate, 2-vinyl-2- Oxazoline, 2-isopropenyl-2- Oxazoline, etc.

[0147] The unsaturated group-containing compound (b22) is preferably used in a ratio (addition rate) of 50 mol % or more, more preferably 60 mol % or more, and further preferably 70 mol % or more, relative to the molar number of the functional group-containing monomer in the acrylic copolymer (b21).

[0148] In addition, the unsaturated group-containing compound (b22) is preferably used in a ratio of 95 mol% or less, more preferably 93 mol% or less, and further preferably 90 mol% or less, relative to the molar number of the functional group-containing monomer of the acrylic copolymer (b21).

[0149] In the reaction of the acrylic copolymer (b21) and the unsaturated group-containing compound (b22), the temperature, pressure, solvent, time, presence or absence of a catalyst, and the type of catalyst can be appropriately selected according to the combination of the functional groups of the acrylic copolymer (b21) and the functional groups of the unsaturated group-containing compound (b22). Thus, the functional groups of the acrylic copolymer (b21) react with the functional groups of the unsaturated group-containing compound (b22), and unsaturated groups are introduced into the side chains of the acrylic copolymer (b21), thereby obtaining an energy-ray-curable polymer (b2).

[0150] The weight average molecular weight (Mw) of the energy beam curable polymer (b2) is preferably 10,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more.

[0151] The weight average molecular weight (Mw) of the energy beam curable polymer (b2) is preferably 1.5 million or less, more preferably 1 million or less.

[0152] Photopolymerization initiator (C)

[0153] When the pressure-sensitive adhesive layer contains an ultraviolet-curable compound (for example, an ultraviolet-curable resin), the pressure-sensitive adhesive layer preferably contains a photopolymerization initiator (C).

[0154] By containing the photopolymerization initiator (C) in the pressure-sensitive adhesive layer, the polymerization curing time and the light irradiation amount can be reduced.

[0155] Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoylbenzoic acid, benzoylbenzoic acid methyl ester, benzoin dimethyl ether, 2,4-diethylthiazolone, 1-hydroxycyclohexylphenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, bibenzyl, diacetyl, β-chloroanthraquinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazyl N,N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}, and 2,2-dimethoxy-1,2-diphenylethane-1-one. These photopolymerization initiators may be used alone or in combination of two or more.

[0156] When the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1) are blended in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the total amount of the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1).

[0157] In addition, when an energy-ray curable resin (a1) and a (meth) acrylic copolymer (b1) are formulated in the adhesive layer, the photopolymerization initiator (C) is preferably used in an amount of 10 parts by mass or less, and more preferably used in an amount of 6 parts by mass or less, relative to 100 parts by mass of the total amount of the energy-ray curable resin (a1) and the (meth) acrylic copolymer (b1).

[0158] The pressure-sensitive adhesive layer may contain other components as appropriate in addition to the above components. Examples of other components include a crosslinking agent (E) and the like.

[0159] Cross-linking agent (E)

[0160] As the crosslinking agent (E), a polyfunctional compound reactive with the functional group of the (meth)acrylic copolymer (b1) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, Oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, and reactive phenolic resins, etc.

[0161] The amount of the crosslinking agent (E) to be blended is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, and even more preferably 0.04 parts by mass or more, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0162] The amount of the crosslinking agent (E) is preferably 8 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3.5 parts by mass or less, based on 100 parts by mass of the (meth)acrylic copolymer (b1).

[0163] The thickness of the adhesive layer is not particularly limited. For example, the thickness of the adhesive layer is preferably 10 μm or more, more preferably 20 μm or more. In addition, the thickness of the adhesive layer is preferably 150 μm or less, more preferably 100 μm or less.

[0164] (Peel-off Sheet)

[0165] For the adhesive sheet of the present embodiment, a release sheet may be laminated on the adhesive surface to protect the adhesive surface until the adhesive surface is attached to an adherend (e.g., a semiconductor chip, etc.). The composition of the release sheet is arbitrary. As an example of a release sheet, a plastic film that has been subjected to a release treatment using a release agent, etc., can be exemplified.

[0166] Specific examples of plastic films include polyester films and polyolefin films. Polyester films include films of polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate. Polyolefin films include films of polypropylene or polyethylene.

[0167] As the release agent, silicone-based, fluorine-based, and long-chain alkyl-based release agents can be used. Among these release agents, silicone-based release agents are preferred because they are inexpensive and can provide stable performance.

[0168] The thickness of the release sheet is not particularly limited, but is generally 20 μm or more and 250 μm or less.

[0169] [Method for producing adhesive sheet]

[0170] The pressure-sensitive adhesive sheet of the present embodiment can be produced in the same manner as conventional pressure-sensitive adhesive sheets.

[0171] The method for producing the pressure-sensitive adhesive sheet is not particularly limited as long as the pressure-sensitive adhesive layer described above can be laminated on one side of a substrate.

[0172] As an example of a method for manufacturing an adhesive sheet, the following method can be cited. First, a coating liquid containing an adhesive composition constituting an adhesive layer and further containing a solvent or a dispersion medium as needed is prepared. Next, the coating liquid is applied to one side of the substrate using a coating mechanism to form a coating film. As a coating mechanism, for example: a die coater, a curtain coater, a spray coater, a slit coater, and a blade coater can be cited. Next, by drying the coating film, an adhesive layer can be formed. As long as the coating liquid can be applied, its properties are not particularly limited. The coating liquid contains both a component for forming an adhesive layer as a solute and a component for forming an adhesive layer as a dispersion medium.

[0173] In addition, as another example of the manufacturing method of the adhesive sheet, the following method can be cited. First, a coating liquid is applied to the release surface of the above-mentioned release sheet to form a coating film. Next, the coating film is dried to form a laminate consisting of an adhesive layer and a release sheet. Next, a substrate can be attached to the surface of the adhesive layer of the laminate that is opposite to the release sheet side to obtain a laminate of an adhesive sheet and a release sheet. The release sheet in the laminate can be peeled off as a process material, or it can protect the adhesive layer until an adherend (for example, a semiconductor chip and a semiconductor wafer, etc.) is attached to the adhesive layer.

[0174] When the coating liquid contains a crosslinking agent, the (meth)acrylic copolymer (b1) in the coating film and the crosslinking agent can be crosslinked by changing the drying conditions of the coating film (e.g., temperature and time, etc.) or by separately performing a heat treatment, so as to form a crosslinked structure in the adhesive layer at a desired density. In order to allow the crosslinking reaction to proceed sufficiently, after laminating the adhesive layer on the substrate by the above-mentioned method, the obtained adhesive sheet can be conditioned by standing for several days in an environment of, for example, 23° C. and a relative humidity of 50%.

[0175] The thickness of the pressure-sensitive adhesive sheet of the present embodiment is preferably 30 μm or more, more preferably 50 μm or more. The thickness of the pressure-sensitive adhesive sheet is preferably 400 μm or less, more preferably 300 μm or less.

[0176] [How to use the adhesive sheet]

[0177] Since the adhesive sheet of the present embodiment can be bonded to various adherends, the adherend to which the adhesive sheet of the present embodiment can be applied is not particularly limited. For example, as the adherend, a semiconductor chip and a semiconductor wafer are preferred.

[0178] The pressure-sensitive adhesive sheet of this embodiment can be used for semiconductor processing, for example.

[0179] The adhesive sheet is preferably used in a chip expanding step for expanding the interval between a plurality of semiconductor chips in a semiconductor device manufacturing step.

[0180] The plurality of semiconductor chips are preferably bonded to the center portion of the adhesive sheet.

[0181] In addition, the plurality of semiconductor chips are preferably semiconductor chips obtained by cutting a semiconductor wafer. For example, a semiconductor wafer attached to a cutting sheet is cut and divided into a plurality of semiconductor chips, and the plurality of semiconductor chips obtained by the division can be directly transferred to the adhesive sheet of the present embodiment, or after being transferred to another adhesive sheet, the other adhesive sheet is transferred to the adhesive sheet of the present embodiment.

[0182] The expansion interval of multiple semiconductor chips depends on the size of the semiconductor chips and is not particularly limited. The adhesive sheet of this embodiment is preferably used to expand the mutual spacing of adjacent semiconductor chips in multiple semiconductor chips attached to one side of the adhesive sheet to more than 200 μm. It should be noted that there is no particular limit on the upper limit of the mutual spacing of the semiconductor chips. The upper limit of the mutual spacing of the semiconductor chips can be, for example, 6000 μm.

[0183] In addition, the adhesive sheet of this embodiment can also be used in the case where the interval between multiple semiconductor chips stacked on one side of the adhesive sheet is expanded by at least biaxial stretching. In this case, the adhesive sheet is stretched by applying tension along four directions of the +X axis direction, -X axis direction, +Y axis direction and -Y axis direction of the mutually orthogonal X axis and Y axis, for example, and more specifically, stretched along the MD direction and CD direction of the substrate.

[0184] Such biaxial stretching can be performed, for example, using a separation device that applies tension in the X-axis direction and the Y-axis direction. Here, the X-axis and the Y-axis are orthogonal axes, one of the directions parallel to the X-axis is set as the +X-axis direction, the direction opposite to the +X-axis direction is set as the -X-axis direction, one of the directions parallel to the Y-axis is set as the +Y-axis direction, and the direction opposite to the +Y-axis direction is set as the -Y-axis direction.

[0185] The above-mentioned separation device applies tension to the adhesive sheet in four directions, namely, the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction. For each of the four directions, it is preferred to have a plurality of holding mechanisms and a plurality of tension applying mechanisms corresponding to these holding mechanisms. The number of holding mechanisms and tension applying mechanisms in each direction depends on the size of the adhesive sheet, and can be, for example, more than 3 and less than 10.

[0186] Here, for example, in a group including a plurality of holding mechanisms and a plurality of tension imparting mechanisms provided in order to impart tension in the +X-axis direction, it is preferred that each holding mechanism has a holding member for holding an adhesive sheet, and each tension imparting mechanism causes the holding member corresponding to the tension imparting mechanism to move in the +X-axis direction to impart tension to the adhesive sheet. Furthermore, the plurality of tension imparting mechanisms are each independently preferably provided in such a manner that the holding mechanism can be moved in the +X-axis direction. In addition, in three groups including a plurality of holding mechanisms and a plurality of tension imparting mechanisms provided in order to impart tension in the -X-axis direction, the +Y-axis direction, and the -Y-axis direction, respectively, it is also preferred to have the same structure. Thus, the above-mentioned separation device can impart tensions of different sizes to the adhesive sheet in each region in a direction orthogonal to each direction.

[0187] Generally, when the adhesive sheet is held in the +X axis direction, -X axis direction, +Y axis direction and -Y axis direction by four holding members and stretched in the four directions, in addition to the four directions, tension is applied to the adhesive sheet in the combined direction thereof (e.g., the combined direction of the +X axis direction and the +Y axis direction, the combined direction of the +Y axis direction and the -X axis direction, the combined direction of the -X axis direction and the -Y axis direction, and the combined direction of the -Y axis direction and the +X axis direction). As a result, a difference may sometimes be caused between the intervals of the semiconductor chips in the inner area of ​​the adhesive sheet and the intervals of the semiconductor chips in the outer area.

[0188] However, in the above-mentioned separation device, multiple tension-applying mechanisms can independently apply tension to the adhesive sheet in each of the +X-axis direction, the -X-axis direction, the +Y-axis direction and the -Y-axis direction, thereby achieving stretching of the adhesive sheet in a manner that eliminates the difference in the spacing between the inner and outer sides of the above-mentioned adhesive sheet.

[0189] As a result, the interval between semiconductor chips can be accurately adjusted.

[0190] The above-mentioned separation device is preferably further provided with a measuring mechanism for measuring the mutual spacing of the semiconductor chips. Here, the above-mentioned tension applying mechanism is preferably arranged in a manner capable of individually moving the plurality of holding members based on the measurement result of the measuring mechanism. By providing the above-mentioned separation device with the measuring mechanism, the spacing can be further adjusted based on the measurement result of the semiconductor chip spacing obtained by the above-mentioned measuring mechanism, and as a result, the spacing of the semiconductor chips can be adjusted more accurately.

[0191] It should be noted that, in the above-mentioned detachment device, as a holding mechanism, a chuck mechanism and a decompression mechanism can be cited. As a chuck mechanism, for example, a mechanical chuck and a chuck cylinder can be cited. As a decompression mechanism, for example, a decompression pump and a vacuum extractor can be cited. In addition, in the above-mentioned detachment device, as a holding mechanism, it can be a structure that supports the adhesive sheet by an adhesive or magnetic force. In addition, as a holding member in the chuck mechanism, for example, a holding member having a lower supporting member that supports the adhesive sheet from below, a driving device supported by the lower supporting member, and a holding member having a structure that is supported by the output shaft of the driven device and can press the adhesive sheet from above by the drive of the driving device can be used. As the driving device, for example, an electric device and a transmission can be cited. As an electric device, for example: a rotary motor, a direct-acting motor, a linear motor, a single-axis robot, and a multi-joint robot can be cited. As a transmission, for example: a cylinder, a hydraulic cylinder, a rodless cylinder, and a rotary cylinder can be cited.

[0192] In addition, in the above-mentioned separation device, the tension applying mechanism may have a driving device, and the holding member may be moved by the driving device. As the driving device provided by the tension applying mechanism, the same driving device as the driving device provided by the above-mentioned holding member may be used. For example, the tension applying mechanism may be a structure including a direct-acting motor as a driving device and an output shaft sandwiched between the direct-acting motor and the holding member, and the driven direct-acting motor may move the holding member via the output shaft.

[0193] When the spacing between semiconductor chips is expanded using the adhesive sheet of this embodiment, the spacing can be expanded from a state where the semiconductor chips are in contact with each other, or from a state where the spacing between the semiconductor chips is basically not expanded, or from a state where the spacing between the semiconductor chips has been expanded to a given spacing, the spacing can be further expanded.

[0194] As a case where the semiconductor chips are in contact with each other or the interval between the semiconductor chips is not substantially expanded, for example, a semiconductor wafer may be divided on a dicing sheet to obtain a plurality of semiconductor chips, and then the plurality of semiconductor chips may be transferred from the dicing sheet to the adhesive sheet of the present embodiment, and then the interval between the semiconductor chips may be expanded. Alternatively, a semiconductor wafer may be divided on the adhesive sheet of the present embodiment to obtain a plurality of semiconductor chips, and then the interval between the semiconductor chips may be expanded.

[0195] As a case where the interval between semiconductor chips is further expanded from a state where the interval between them has been expanded to a given interval, after the interval between the semiconductor chips is expanded to a given interval using another adhesive sheet, preferably using the adhesive sheet of the present embodiment (the first stretching adhesive sheet), the semiconductor chips can be transferred from the sheet (the first stretching adhesive sheet) to the adhesive sheet of the present embodiment (the second stretching adhesive sheet), and then the adhesive sheet of the present embodiment (the second stretching adhesive sheet) is stretched, thereby further expanding the interval between the semiconductor chips. It should be noted that such transfer of semiconductor chips and stretching of adhesive sheets can be repeated multiple times until the interval between the semiconductor chips reaches the desired distance.

[0196] [Second embodiment]

[0197] [Adhesive sheet]

[0198] The pressure-sensitive adhesive sheet of the present embodiment has a substrate and a pressure-sensitive adhesive layer, similarly to the pressure-sensitive adhesive sheet of the first embodiment.

[0199] The adhesive layer of this embodiment is different from the adhesive sheet of the first embodiment in that it contains an energy-ray curable resin and has cured portions where the energy-ray curable resin is cured and uncured portions where the energy-ray curable resin is not cured at both widthwise ends of the adhesive layer.

[0200] In the pressure-sensitive adhesive sheet of the present embodiment, the ratio of the tensile strengths measured by a tensile testing machine on a first test piece and a second test piece prepared from an uncured portion of the pressure-sensitive adhesive sheet satisfies a given range.

[0201] In the following description, the parts different from the first embodiment are mainly described, and the overlapping description is omitted or simplified. The same components as the first embodiment are denoted by the same reference numerals, and the description is omitted or simplified.

[0202] The pressure-sensitive adhesive sheet of the present embodiment also has a substrate and a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet may be in any shape, such as a tape shape (long strip shape) or a label shape (sheet shape).

[0203] exist Figure 4 Schematic cross-sectional view of a pressure-sensitive adhesive sheet 1A according to the present embodiment is shown in FIG.

[0204] The adhesive sheet 1A includes a substrate 10 and an adhesive layer 20. The adhesive layer 20 contains an energy-ray curable resin. The adhesive layer 20 includes a cured portion 22 formed by curing the energy-ray curable resin and an uncured portion 21 in which the energy-ray curable resin is not cured. The cured portion 22 is formed by curing the energy-ray curable resin. Figure 4As shown, the adhesive layer 20 of the adhesive sheet 1A is formed at both ends in the width direction. An uncured portion 21 is provided between the cured portion 22 at one end side and the cured portion 22 at the other end side in the width direction.

[0205] Cured portions 22 are formed at both widthwise ends of the PSA sheet 1A by curing opposite sides of the PSA sheet 1A with energy rays. The cured portions 22 prevent the adhesive in the uncured portions 21 from oozing out of the PSA sheet 1A from the widthwise ends.

[0206] The cross-sectional shape of the solidified portion 22 is Figure 4 The shape is a rectangle, but it is not limited to a rectangle and any shape may be used as long as the bleeding of the adhesive can be suppressed.

[0207] The cured portion 22 is preferably formed continuously along both ends in the width direction of the adhesive sheet 1A. By forming the cured portion 22 continuously in the entire length direction of the adhesive sheet 1A, it is easier to suppress the adhesive from seeping out of the sheet from the uncured portion 21 to the ends in the sheet width direction. In the case where the cured portion 22 is formed discontinuously, there is a risk of the adhesive seeping out from the portion where the cured portion 22 is not formed.

[0208] When the adhesive sheet 1A is a long sheet, the cured portion 22 is preferably formed continuously along the entire length direction of the adhesive sheet 1A. By forming the cured portion 22 continuously along the entire length direction of the adhesive sheet 1A, it is easier to prevent the adhesive of the uncured portion 21 from seeping out of the sheet from the end portions in the sheet width direction.

[0209] exist Figure 5 FIG. 1 is a perspective view showing a long-strip adhesive sheet 1A wound into a roll. Figure 5 , the state where the adhesive sheet 1A is partially pulled out from the roll is shown.

[0210] like Figure 5 As shown in FIG. 1 , a cured portion 22 is formed at both ends of the adhesive sheet 1A in the width direction, and an uncured portion 21 is provided between the cured portion 22 at one end side and the cured portion 22 at the other end side in the width direction. The cured portion 22 is formed continuously in the entire length direction of the adhesive sheet 1A. Figure 5 The roll formed by winding the long strip of adhesive sheet 1A shown is often stored in a manner such that the width direction of the roll is perpendicular to the loading surface. Therefore, by continuously forming the cured portion 22 at both ends in the width direction of the adhesive sheet 1A, it is easy to suppress the adhesive from seeping out from the uncured portion 21 when the roll is stored.

[0211] The width of the cured portion 22 is preferably 0.5 mm or more, respectively. If the width of the cured portion 22 is 0.5 mm or more, it is easier to suppress the adhesive of the uncured portion 21 from the end portion in the width direction of the sheet to the outside of the sheet. In the case where the cured portion 22 is formed continuously along the end portion in the width direction, the width of the cured portion 22 may not be constant in the entire length direction, and is preferably formed with a width of 0.5 mm or more in the entire length direction.

[0212] The width of each cured portion 22 is preferably 10 mm or less. When the cured portion 22 is formed continuously along the width direction end portion, the width of the cured portion 22 is preferably 10 mm or less in the entire length direction.

[0213] It should be noted that the larger the width of the cured portion 22, the easier it is to suppress the seepage of the adhesive. On the other hand, the area of ​​the uncured portion 21 becomes narrower. Therefore, from the perspective of suppressing the seepage of the adhesive and ensuring the area of ​​the uncured portion 21 having adhesive force as an adhesive sheet, it is preferred to set an upper limit to the width of the cured portion 22.

[0214] (First test piece)

[0215] The first test piece was prepared from the region of the uncured portion 21 of the pressure-sensitive adhesive sheet 1A of the present embodiment. The width of the first test piece was 25 mm.

[0216] The state in which the first test piece of this embodiment is clamped is similar to the state in which the first test piece of the embodiment is clamped. Figure 2 The first clamp 110 of the tensile tester clamps the substrate 10 and the uncured portion 21 of the adhesive layer 20 at one end of the first test piece, and the second clamp 120 of the tensile tester clamps the substrate 10 and the uncured portion 21 of the adhesive layer 20 at the other end of the first test piece.

[0217] (Second test piece)

[0218] The second test piece is made by attaching two semiconductor chips to the first test piece made of the adhesive sheet 1A of this embodiment. In this embodiment, the two semiconductor chips are the first semiconductor chip and the second semiconductor chip. The dimensions of the first semiconductor chip and the second semiconductor chip are both 45 mm in the vertical dimension, 35 mm in the horizontal dimension, and 0.625 mm in the thickness dimension.

[0219] The first semiconductor chip and the second semiconductor chip were bonded together so that the sides having a vertical dimension of 45 mm were aligned with the longitudinal direction of the first test piece.

[0220] The first semiconductor chip was attached to one end of the first test piece in the longitudinal direction. The second semiconductor chip was attached to the other end of the first test piece in the longitudinal direction. The interval between the first semiconductor chip and the second semiconductor chip attached to the first test piece was set to 35 μm.

[0221] The state of the second test piece of this embodiment being clamped is different from that shown in the first embodiment. Figure 3 The first clamp 110 of the tensile tester is used to clamp the substrate 10, the uncured portion 21 of the adhesive layer 20 and the first semiconductor chip CP1 at one end of the second test piece, and the second clamp 120 of the tensile tester is used to clamp the substrate 10, the uncured portion 21 of the adhesive layer 20 and the second semiconductor chip CP2 at the other end of the second test piece.

[0222] (Tensile Strength)

[0223] In the pressure-sensitive adhesive sheet 1A of the present embodiment, the tensile strengths of the first test piece and the second test piece measured using a tensile tester also satisfy the relationship of the following mathematical formula (Mathematical Formula 1A).

[0224] F B1 / F A1 ≤30···(Mathematical formula 1A)

[0225] In the above formula (Formula 1A), the tensile strength F A1 This is the strength when the substrate and the adhesive layer at each end in the longitudinal direction of the first test piece are clamped with a clamp and stretched by 0.5 mm using a tensile tester.

[0226] In the above formula (Formula 1A), the tensile strength F B1 This is the strength when the substrate, the adhesive layer and the semiconductor chip at both ends of the second test piece in the longitudinal direction are clamped with a clamp and stretched by 0.5 mm using a tensile tester.

[0227] A third test piece is prepared by cutting a length of 150 mm and a width of 25 mm along the length direction of the adhesive sheet 1A in a manner that includes a cured portion 22 formed by curing an energy-ray-curing resin. The third test piece is clamped by a pair of chucks with the distance between the chucks set to 100 mm. When the third test piece is stretched at a speed of 5 mm / sec until the distance between the chucks reaches 200 mm, it is preferred that no warping occurs at the interface between the cured portion 22 and the substrate 10.

[0228] If the curing portion of the adhesive sheet is stretched (for example, when the adhesive sheet is expanded), the interface between the curing portion and the substrate is lifted, the lifted curing portion is broken from the adhesive layer, and the broken curing portion is scattered, which may cause the adherend and the expansion device attached to the adhesive sheet to cause contamination. However, the adhesive sheet 1A of this embodiment does not lift at the interface between the curing portion 22 and the substrate 10 in the tensile test using the third test piece, so it is easy to suppress the contamination of the adherend and the expansion device caused by the broken curing portion as described above. In order to prevent the curing portion 22 from lifting at the interface with the substrate 10, for example, a method of controlling the degree of curing of the energy ray curable resin can be cited.

[0229] The adhesive sheet 1A of the present embodiment is stretched along a first direction, a second direction opposite to the first direction, a third direction perpendicular to the first direction, and a fourth direction opposite to the third direction. When the area ratio (S2 / S1)×100 of the area S1 of the adhesive sheet 1A before stretching to the area S2 of the adhesive sheet 1A after stretching is 381%, it is preferred that the cured portion 22 of the adhesive layer 20 does not peel off at the interface with the substrate 10.

[0230] The first direction, the second direction, the third direction and the fourth direction preferably correspond to the four directions of the +X axis direction, -X axis direction, +Y axis direction and -Y axis direction of the biaxial stretching described later, for example. As an apparatus for stretching along the four directions, for example, a sheet expanding apparatus described later can be cited.

[0231] When the adhesive sheet 1A of this embodiment is stretched along four directions and the area ratio (S2 / S1)×100 before and after the stretching is 381%, the cured portion 22 of the adhesive layer 20 does not peel off at the interface of the substrate 10. Therefore, even if the adhesive sheet 1A is used in a sheet expansion process with a high elongation rate, it is easy to control the contamination of the adherend and the sheet expansion device caused by the broken cured portion.

[0232] [Method for producing adhesive sheet]

[0233] The method for producing the pressure-sensitive adhesive sheet 1A according to the present embodiment includes the following steps (P1) to (P3).

[0234] (P1) A step of applying an adhesive composition containing an energy-ray-curable resin onto the substrate 10 to form the adhesive layer 20 .

[0235] (P2) A step of irradiating both end portions in the width direction of the adhesive layer 20 with energy rays UV to cure the energy ray curable resin to form the cured portion 22 .

[0236] (P3) A step of cutting the outside of the cured portion 22 while leaving all or part of the cured portion 22 outside both ends in the width direction of the uncured portion 21 where the energy-beam-curable resin has not been cured.

[0237] The pressure-sensitive adhesive sheet 1A of the present embodiment can be produced, for example, as follows.

[0238] First, as step (P1), the adhesive layer 20 is formed on the substrate 10. In the present embodiment, the adhesive layer 20 can be formed in the same manner as in the first embodiment, for example.

[0239] Fig. 6A This is a schematic cross-sectional view for explaining the step (P2) of forming the cured portion 22 at both ends in the width direction of the pressure-sensitive adhesive sheet 1A.

[0240] Since the adhesive layer 20 contains an energy ray curable resin, irradiating both ends in the width direction with energy rays UV forms a cured portion 22. When the energy ray curable resin is an ultraviolet curable resin, ultraviolet rays are irradiated as energy rays.

[0241] The cured portion 22 is preferably formed to have a width larger than the width of the cured portion 22 required when used as the pressure-sensitive adhesive sheet 1A.

[0242] Figure 6B This is a schematic cross-sectional view for explaining the step (P3) of cutting both end portions in the width direction of the pressure-sensitive adhesive sheet 1A so that the cured portion 22 remains after the cured portion 22 is formed by irradiating the energy ray.

[0243] exist Figure 6B In the embodiment, the cured portion 22 is cut at positions C1 and C2, which are formed with a width greater than the width required when used as the adhesive sheet 1A. Cutting by cutting the cured portion 22 can prevent the adhesive from adhering to the cutting blade. The cut is formed along the length direction of the cured portion 22.

[0244] The width of the cured portion 22 remaining outside both ends of the uncured portion 21 in the width direction (the distance from the boundary between the uncured portion 21 and the cured portion 22 to the position C1 or the position C2 in cross-sectional view) is preferably 0.5 mm or more.

[0245] exist Figure 6C 2 shows the pressure-sensitive adhesive sheet 1A having the cured portions 22 formed at both ends in the width direction after being cut in step (P3), and the end material 1a.

[0246] It is preferable that the process (P3) of cutting the outer side of the cured portion 22 is followed by a further process of winding the cut pressure-sensitive adhesive sheet 1A into a roll.

[0247] [How to use the adhesive sheet]

[0248] The pressure-sensitive adhesive sheet 1A of the present embodiment can also be used in the same manner as the pressure-sensitive adhesive sheet of the first embodiment.

[0249] The adhesive sheet 1A of the present embodiment can be used, for example, for semiconductor processing applications. In the process of manufacturing a semiconductor device, it is preferable to use the adhesive sheet 1A in a chip expansion process for expanding the interval between a plurality of semiconductor chips.

[0250] The plurality of semiconductor chips are preferably bonded to the center portion (uncured portion 21 ) of the adhesive sheet 1A.

[0251] In the sheet expanding step, the cured portion 22 of the pressure-sensitive adhesive sheet 1A is preferably held by a holding mechanism of a separating device.

[0252] The adhesive sheet 1A of the present embodiment can suppress the oozing out of the adhesive and can reduce the difference in the amount of elongation of the adhesive sheet in the in-plane direction when the adhesive sheet is stretched in the sheet expanding step to expand the distance between semiconductor chips, and has excellent expandability.

[0253] [Variations of Embodiments]

[0254] The present invention is not limited to the above-described embodiment at all, and the present invention includes embodiments obtained by modifying the above-described embodiment, etc., within the scope that can achieve the object of the present invention.

[0255] Example

[0256] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

[0257] (Manufacturing of adhesive sheet)

[0258] [Example 1]

[0259] An acrylic copolymer was obtained by copolymerizing 62 parts by mass of butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA). A solution of a resin (Acryl A) was prepared by adding 2-isocyanatoethyl methacrylate (produced by Showa Denko K.K., product name "Karenz MOI" (registered trademark)) to the acrylic copolymer (adhesive main agent, solid content 35.0% by mass). The addition rate was 80% by mole of 2-isocyanatoethyl methacrylate relative to 100% by mole of 2HEA in the acrylic copolymer.

[0260] The weight average molecular weight (Mw) of the obtained resin (Acryl A) was 90,000, and Mw / Mn was 4.5. The weight average molecular weight Mw and number average molecular weight Mn in terms of standard polystyrene were measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw / Mn) was determined from the measured values.

[0261] UV resin A (10-functional urethane acrylate, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "UV-5806", Mw = 1740, containing a photopolymerization initiator) and a toluene diisocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") as a crosslinking agent were added to the adhesive main agent. 50 parts by mass of UV resin A and 0.2 parts by mass of crosslinking agent were added to 100 parts by mass of the solid content in the adhesive main agent. After the addition, the mixture was stirred for 30 minutes to prepare an adhesive composition A1.

[0262] Next, the prepared solution of PSA composition A1 was applied to a polyethylene terephthalate (PET) release film (manufactured by Lintec Corporation, product name "SP-PET381031", thickness 38 μm) and dried to form a 40 μm thick PSA layer on the release film.

[0263] A polyester polyurethane elastomer sheet (manufactured by Sheedom, product name "Higress DUS202", thickness 100 μm) as a substrate was bonded to the PSA layer, and then unnecessary portions at the ends in the width direction were cut off to prepare a PSA sheet.

[0264] [Example 2]

[0265] An acrylic copolymer was obtained by copolymerizing 52 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA). A solution (adhesive main agent) of a resin (Acryl A2) was prepared by adding 2-isocyanatoethyl methacrylate (produced by Showa Denko K.K., product name "Karenz MOI" (registered trademark)) to the acrylic copolymer. The addition rate was 90 mol% of 2-isocyanatoethyl methacrylate relative to 100 mol% of 2HEA in the acrylic copolymer.

[0266] The weight average molecular weight (Mw) of the obtained resin (Acryl A2) was 600,000, and Mw / Mn was 4.5. The weight average molecular weight Mw and number average molecular weight Mn in terms of standard polystyrene were measured by gel permeation chromatography (GPC), and the molecular weight distribution (Mw / Mn) was determined from the measured values.

[0267] To the adhesive main agent, an energy-ray curable resin A (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., product name "SA-TE60"), a photopolymerization initiator (manufactured by IGM Resins BV, product name "Omnirad 127D"), and a crosslinking agent (manufactured by TOYOCHEM, TMP-TDI (trimethylolpropane adduct of toluene diisocyanate)) were added. With respect to 100 parts by mass of the solid content in the adhesive main agent, 18 parts by mass of the energy-ray curable resin A, 1.3 parts by mass of the photopolymerization initiator, 0.2 parts by mass of the crosslinking agent, and ethyl acetate were added, and then stirred for 30 minutes to prepare an adhesive composition A1 having a solid content of 35.0% by mass.

[0268] Next, the prepared solution of adhesive composition A1 was applied to a polyethylene terephthalate (PET) release film (manufactured by Lintec Corporation, product name "PET752150"), and the coated film was dried at 90°C for 90 seconds and further dried at 100°C for 90 seconds to form an adhesive layer with a thickness of 30 μm on the release film.

[0269] A urethane substrate (product name "U-1490" manufactured by Kurabo Co., Ltd., thickness 100 μm, hardness 90 degrees (Type A)) was bonded to the adhesive layer to prepare an adhesive tape.

[0270] When the adhesive tape is cut into a width of 300 mm, two LED-UV units are set at the position of each cutting portion in a manner that spans the cutting portion. The distance between the front end of the lens of the LED-UV unit and the tape is set to 10 mm. Regarding the output power of the LED-UV unit, UV irradiation is performed with an output power of 50% for both units, and a cured portion is formed in the adhesive layer. The adhesive tape is cut along the formed cured portion to produce an adhesive sheet (width 300 mm) having a cured portion at both ends in the width direction. The width of the cured portion at both ends of the sheet in the width direction is shown in Table 2 and is set to 1.00 mm respectively. The cutting speed during cutting is set to 10 m / min. In addition, the relationship between the output power of the LED-UV unit and the amount of light and illumination of each LED-UV unit is shown in Table 2.

[0271] The description of the LED-UV unit used in Example 2 is as follows.

[0272] LED-UV unit

[0273] Made by HOYA CANDEO OPTRONICS

[0274] Control unit = H-1VC II

[0275] Light emitting part = H-1VH4

[0276] Lens = HO-03L

[0277] [Example 3]

[0278] The adhesive sheet of Example 3 was produced in the same manner as Example 2 except that the output power of the LED-UV unit in the production of the adhesive sheet of Example 2 was changed to 40% and the width of the cured portion at both ends of the sheet in the width direction was set to 0.50 mm as shown in Table 2.

[0279] [Example 4]

[0280] The adhesive sheet of Example 4 was produced in the same manner as Example 2 except that the output power of the LED-UV unit in the production of the adhesive sheet of Example 2 was changed to 90% and the width of the cured portion at both ends of the sheet in the width direction was set to 1.25 mm as shown in Table 2.

[0281] [Example 5]

[0282] For the adhesive sheet of Example 5, the substrate used in the preparation of the adhesive sheet of Example 2 was changed to pure pulp paper (weight per unit area: 60 g / m 2 ), except for this, it was produced in the same manner as Example 2.

[0283] [Example 6]

[0284] The pressure-sensitive adhesive sheet of Example 6 was produced in the same manner as in Example 2 except that the substrate in the production of the pressure-sensitive adhesive sheet of Example 2 was changed to a polyethylene terephthalate film (thickness: 50 μm).

[0285] [Comparative Example 1]

[0286] A PSA sheet was prepared in the same manner as in Example 1 except that the PSA main agent was changed as follows.

[0287] An acrylic copolymer was obtained by copolymerizing 52 parts by mass of butyl acrylate (BA), 20 parts by mass of methyl methacrylate (MMA), and 28 parts by mass of 2-hydroxyethyl acrylate (2HEA). A solution of a resin (Acryl B) was prepared by adding 2-isocyanatoethyl methacrylate (manufactured by Showa Denko K.K., product name "Karenz MOI" (registered trademark)) to the acrylic copolymer (adhesive main agent, solid content 35.0% by mass). The addition rate was 90% by mole of 2-isocyanatoethyl methacrylate relative to 100% by mole of 2HEA in the acrylic copolymer.

[0288] The weight average molecular weight (Mw) of the obtained resin (Acryl B) was 600,000, and Mw / Mn was 4.5. The weight average molecular weight Mw and molecular weight distribution (Mw / Mn) of the resin (Acryl B) of Comparative Example 1 were determined in the same manner as in Example 1.

[0289] [Comparative Example 2]

[0290] The pressure-sensitive adhesive sheet of Comparative Example 2 was produced in the same manner as in Example 2, except that UV irradiation was not performed in the production of the pressure-sensitive adhesive sheet of Example 2.

[0291] [Evaluation of Adhesive Sheet]

[0292] The following evaluations were performed on the produced pressure-sensitive adhesive sheets.

[0293] <Measurement method>

[0294] (Determination method of tensile strength)

[0295] As a tensile testing machine for measuring the tensile strength, Autograph AG-IS manufactured by Shimadzu Corporation was used.

[0296] A first test piece having a width of 25 mm was prepared from the PSA sheet. For the PSA sheet having a cured portion and an uncured portion, a first test piece was prepared from a region of the PSA sheet corresponding to the uncured portion.

[0297] The first semiconductor chip and the second semiconductor chip were bonded to the first test piece to produce the second test piece. Both the first semiconductor chip and the second semiconductor chip had a vertical dimension of 45 mm, a horizontal dimension of 35 mm, and a thickness of 0.625 mm.

[0298] The first semiconductor chip and the second semiconductor chip were bonded together so that their sides, each having a vertical dimension of 45 mm, were aligned along the longitudinal direction of the first test piece.

[0299] The first semiconductor chip was attached to one end of the first test piece in the longitudinal direction. The second semiconductor chip was attached to the other end of the first test piece in the longitudinal direction. The interval between the first semiconductor chip and the second semiconductor chip attached to the first test piece was set to 35 μm.

[0300] The substrate and adhesive layer at both ends of the first test piece in the longitudinal direction were clamped with a clamp, and the tensile strength was measured using a tensile testing machine. The tensile strength F of the first test piece when stretched by 0.5 mm (when the stretching distance is 0.5 mm) was A1 Shown in Table 1.

[0301] The substrate, adhesive layer and semiconductor chip at both ends of the second test piece in the longitudinal direction were clamped with a clamp, and the tensile strength was measured using a tensile testing machine. The tensile strength F of the second test piece when stretched by 0.5 mm (when the stretching distance is 0.5 mm) was B1 Shown in Table 1.

[0302] The unit of tensile strength is N.

[0303] Other conditions during the tensile test are as follows.

[0304] Distance between fixtures: 50mm

[0305] Stretching speed: 50mm / min

[0306] (Method for measuring Young's modulus)

[0307] According to JIS K7161 and JIS K7127, a tensile test was performed using a universal testing machine ("Autograph AG-IS500N" manufactured by Shimadzu Corporation). In the tensile test, the first test piece and the second test piece were fixed and the tensile test was performed at a tensile speed of 50 mm / min. Then, a stress-strain curve was prepared at this time, and the Young's modulus was calculated based on the slope of the stress-strain curve at the beginning of the test.

[0308] Table 1 shows the results of measuring the Young's modulus of the pressure-sensitive adhesive sheets of Example 1, Example 2, and Comparative Example 1.

[0309] [Table 1]

[0310] Example 1 Example 2 Comparative Example 1 <![CDATA[First test piece: Tensile strength F A1 [N]]]> 0.86 0.50 0.43 <![CDATA[Second test piece: Tensile strength F B1 [N]]]> 7.69 8.70 13.4 <![CDATA[F B1 / F A1 [-]]]> 8.94 17.40 31.16 <![CDATA[First test piece: Young's modulus Y A1 [MPa]]]> 27 19 24 <![CDATA[Second test piece: Young's modulus Y B1 [MPa]]]> 417 334 473 <![CDATA[Y B1 / YA1[-]]]> 15.44 17.58 19.71

[0311] As shown in Table 1, the F B1 / F A1 The ratio of the tensile strength of the adhesive sheet where the semiconductor chip is not bonded to the tensile strength of the adhesive sheet where the semiconductor chip is bonded is 30 or less. B1 / F A1 Therefore, according to the adhesive sheets of Examples 1 and 2, when the adhesive sheets are stretched in the sheet expansion process to expand the distance between the semiconductor chips, the difference in the elongation of the adhesive sheets in the in-plane direction is reduced, the expandability is excellent, and the non-uniformity of the distance between the semiconductor chips can be reduced.

[0312] (Evaluation method for suppression of bleed out of adhesive)

[0313] An adhesive sheet with a width of 300 mm and a cured portion formed at both ends in the width direction was wound up to make a roll. The roll was stored at 40°C, and after 3 days, it was confirmed by visual observation or microscopy whether there was adhesive oozing out of the roll ends. The evaluation criteria for oozing out inhibition were set as follows. In this example, evaluation A was judged as qualified.

[0314] Evaluation criteria for bleed suppression

[0315] Evaluation A: No appearance change at the end of the roll

[0316] Evaluation B: The roll end has a change in appearance

[0317] (Evaluation method of non-uniformity)

[0318] The PSA sheets prepared in Examples and Comparative Examples were cut into a size of 210 mm x 210 mm to obtain PSA sheets for testing. The sheets were cut so that each side was parallel or perpendicular to the MD direction of the substrate in the PSA sheet.

[0319] The silicon wafer was diced so that 49 chips in total were cut out so that chips of 3 mm×3 mm in size were arranged in 7 rows in the X-axis direction and in 7 rows in the Y-axis direction.

[0320] The release film of the test adhesive sheet was peeled off, and a total of 49 chips cut out as described above were attached to the center of the exposed adhesive layer. At this time, the chips were arranged in 7 rows along the X-axis direction and 7 rows along the Y-axis direction, and the distance between the chips was 35 μm in both the X-axis direction and the Y-axis direction.

[0321] Next, the test pressure-sensitive adhesive sheet with the chip attached thereto was placed in a biaxially stretchable sheet expansion device (separation device). Figure 7 A top view illustrating the sheet expanding device 100 is shown in FIG. Figure 7 In the embodiment, the X-axis and the Y-axis are orthogonal to each other, the positive direction of the X-axis is set to the +X-axis direction, the negative direction of the X-axis is set to the -X-axis direction, the positive direction of the Y-axis is set to the +Y-axis direction, and the negative direction of the Y-axis is set to the -Y-axis direction. The test adhesive sheet 200 is arranged in the sheet expansion device 100 in such a way that each side is parallel to the X-axis or the Y-axis. As a result, the MD direction of the substrate in the test adhesive sheet 200 is parallel to the X-axis or the Y-axis. It should be noted that Figure 7 The chip is omitted.

[0322] like Figure 7As shown, the sheet expansion device 100 has five holding mechanisms 101 in the +X axis direction, the -X axis direction, the +Y axis direction, and the -Y axis direction (a total of 20 holding mechanisms 101). Among the five holding mechanisms 101 in each direction, the holding mechanism 101A is located at both ends, the holding mechanism 101C is located in the center, and the holding mechanism 101B is located between the holding mechanism 101A and the holding mechanism 101C. These holding mechanisms 101 are used to clamp each side of the test adhesive sheet 200.

[0323] Here, if Figure 7 As shown, the side length of the test adhesive sheet 200 is 210 mm. In addition, the interval between the holding mechanisms 101 on each side is 40 mm. In addition, the interval between the end (vertex of the sheet) on one side of the test adhesive sheet 200 and the holding mechanism 101A that exists on the side and is closest to the end is 25 mm.

[0324] ·First expansion test

[0325] Next, a plurality of tension imparting mechanisms not shown in the figure corresponding to each holding mechanism 101 are driven to move the holding mechanisms 101 independently. The four sides of the test adhesive sheet are fixed with a clamp, and the test adhesive sheet is expanded at a speed of 5 mm / s and an expansion amount of 200 mm along the X-axis direction and the Y-axis direction. The result of the first expansion test is that the area of ​​the test adhesive sheet is expanded to 381% relative to the area before expansion. In this embodiment, the expansion test with an expansion amount of 200 mm is sometimes referred to as the first expansion test. The adhesive sheets of Examples 5 and 6 cannot be expanded.

[0326] After the test adhesive sheet 200 was expanded by the first sheet expansion test, the expanded state of the test adhesive sheet 200 was maintained by the ring frame.

[0327] In the state of maintaining the expanded state, the standard deviation is calculated based on the positional relationship between the chips, thereby evaluating the non-uniformity. The position of the chip on the test adhesive sheet is measured using a CNC image measuring instrument (manufactured by MITUTOYO, product name "Vision ACCEL"). The standard deviation is calculated using the data analysis software JMP13 manufactured by JMP. The evaluation criteria for non-uniformity are set as described below. In this embodiment, evaluation A or evaluation B is judged to be qualified.

[0328] · Evaluation criteria for non-uniformity

[0329] Evaluation A: The standard deviation was 100 μm or less.

[0330] Evaluation B: The standard deviation was 200 μm or less.

[0331] Evaluation C: The standard deviation was 201 μm or more.

[0332] (Evaluation method of adhesive lifting at 100% elongation)

[0333] The third test piece was prepared by cutting a length of 150 mm and a width of 25 mm along the length direction of the adhesive sheet in a manner that includes a cured portion cured by an energy-ray-curing resin. The third test piece was clamped with a pair of chucks of a tensile testing machine. As a tensile testing machine, Autograph AG-IS manufactured by Shimadzu Corporation was used. The distance between the chucks that clamped the third test piece was set to 100 mm. When the distance between the chucks reached 200 mm at a speed of 5 mm / sec, it was confirmed by visual observation whether the cured portion of the adhesive layer peeled off at the interface with the substrate and warped. The evaluation criteria for the adhesive warping at an elongation of 100% are set as described below. In this embodiment, evaluation A is judged to be qualified.

[0334] ·Evaluation criteria for adhesive lifting at 100% elongation

[0335] Evaluation A: No lifting of the cured portion of the adhesive layer occurred at an elongation of 100%

[0336] Evaluation B: When the elongation is 100%, the cured portion of the adhesive layer lifts up at one or more locations (area expansion evaluation method)

[0337] In the first expansion test, it was confirmed by visual observation whether the cured portion of the adhesive layer peeled off at the interface with the substrate and warped. The evaluation criteria for area expansion are set as described below. In this embodiment, evaluation A was judged to be qualified. The adhesive sheets of Examples 5 and 6 could not be evaluated because they could not expand.

[0338] Evaluation criteria for area scalability

[0339] Evaluation A: No lifting of the cured portion of the adhesive layer occurred in the first sheet expansion test.

[0340] Evaluation B: In the first sheet expansion test, lift-up of the cured portion of the adhesive layer occurred at one or more locations.

[0341] [Table 2]

[0342]

[0343] Since the adhesive sheets of Examples 2 to 6 have cured portions at both ends in the width direction, the adhesive can be prevented from leaking out. In addition, for the adhesive sheets of Examples 2 and 3, no adhesive warping occurred at an elongation of 100% and during the first sheet expansion test. This is believed to be because the cured portions of the adhesive sheets of Examples 2 and 3 are formed by UV irradiation with an output of about 40% to 50%, and the degree of curing of the cured portions is appropriately controlled.

Claims

1. An adhesive sheet for semiconductor processing, comprising a substrate and an adhesive layer, The material of the substrate is a thermoplastic resin elastomer, The substrate contains a urethane elastomer, The thickness of the substrate is 20 μm or more and 250 μm or less. The adhesive layer contains an acrylic adhesive, The adhesive layer contains an energy-ray-curable resin and a (meth)acrylate copolymer different from the energy-ray-curable resin. The adhesive layer includes cured portions at both ends in the width direction of the adhesive layer where the energy-ray curable resin is cured, and uncured portions where the energy-ray curable resin is not cured. The cured portion is formed by UV irradiation with an output power of 40% to 50%, wherein the output power of 40% corresponds to 64.476 mJ / cm 2 The above 50% output power corresponds to 78.624mJ / cm 2 The amount of light, The tensile strength F of the adhesive sheet for semiconductor processing A1 and tensile strength F B1 The relationship satisfying the following mathematical formula (Mathematical formula 1A) is: F B1 / F A1 ≤30···(Mathematical formula 1A) The tensile strength F A1 The first test piece with a width of 25 mm is prepared from the semiconductor processing adhesive sheet corresponding to the uncured portion, the substrate and the uncured portion of the adhesive layer at both ends of the first test piece in the longitudinal direction are clamped with a clamp, and the tensile strength when stretched by 0.5 mm is measured using a tensile tester. The tensile strength F B1 The second test piece is: a second test piece is prepared, the substrate, the adhesive layer of the uncured portion, the first semiconductor chip and the second semiconductor chip are clamped at both ends of the second test piece in the longitudinal direction by a clamp, and the tensile strength when stretched by 0.5 mm is measured using a tensile testing machine, the second test piece is prepared by making the longitudinal dimension of the first semiconductor chip and the longitudinal dimension of the second semiconductor chip 45 mm along the longitudinal direction of the first test piece, the longitudinal dimension of the first semiconductor chip is 45 mm, the transverse dimension is 35 mm, and the thickness dimension is 0.625 mm, and the longitudinal dimension of the first semiconductor chip and the longitudinal dimension of the second semiconductor chip are 45 mm, and the interval between the first semiconductor chip and the second semiconductor chip is set to 35 μm, the first semiconductor chip is bonded to the adhesive layer of the uncured portion at one end side of the longitudinal direction of the first test piece, and the second semiconductor chip is bonded to the adhesive layer of the uncured portion at the other end side of the longitudinal direction of the first test piece, The semiconductor processing adhesive sheet is used in a sheet expansion process in the manufacturing process of a semiconductor device, and the sheet expansion process is used to expand the intervals between multiple semiconductor chips. When the adherend is to be separated from the semiconductor processing adhesive sheet, the separation is achieved by irradiating the adhesive layer with energy rays.

2. The adhesive sheet for semiconductor processing according to claim 1, wherein A third test piece is prepared by cutting a piece having a length of 150 mm and a width of 25 mm along the length direction of the adhesive sheet for semiconductor processing in such a manner as to include a cured portion formed by curing the energy-ray-curable resin. The third test piece is clamped by a pair of chucks with a distance between the chucks set to 100 mm, and is stretched at a speed of 5 mm / sec until the distance between the chucks reaches 200 mm, and no warping occurs at the interface between the cured portion and the substrate.

3. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein The adhesive sheet for semiconductor processing is stretched along a first direction, a second direction opposite to the first direction, a third direction perpendicular to the first direction, and a fourth direction opposite to the third direction. When the area ratio of the adhesive sheet for semiconductor processing after stretching S2 to the area S1 of the adhesive sheet for semiconductor processing before stretching is 381%, the cured portion of the adhesive layer does not peel off at the interface with the substrate.

4. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein The tensile strength F A1 and the tensile strength F B1 Satisfying the relationship of the following mathematical formula (Mathematical formula 1B), 1≤F B1 / F A1 ≤30···(Mathematical formula 1B).

5. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein Young's modulus Y of the first test piece A1 and the Young's modulus Y of the second test piece B1 The relationship satisfying the following mathematical formula (Mathematical formula 2A) is: Y B1 / Y A1 ≤19···(Mathematical formula 2A).

6. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein The (meth)acrylate copolymer is a (meth)acrylate copolymer in which a functional group having energy ray curability is introduced into a side chain.

7. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein The width of the cured portion is independently 0.5 mm or more and 10 mm or less.

8. The adhesive sheet for semiconductor processing according to claim 1 or 2, wherein The adhesive sheet for semiconductor processing is in a long strip shape and is wound into a roll shape.

9. A method for producing an adhesive sheet for semiconductor processing, the method comprising: A step of applying an adhesive composition containing an energy-ray-curable resin and a (meth)acrylate copolymer different from the energy-ray-curable resin to a substrate to form an adhesive layer, wherein the adhesive layer contains an acrylic adhesive; The process of irradiating both ends of the adhesive layer in the width direction with UV having an output of 40% to 50% to cure the energy ray curable resin to form a cured portion, wherein the output of 40% corresponds to 64.476 mJ / cm 2 The above 50% output power corresponds to 78.624mJ / cm 2 The amount of light; as well as The step of leaving all or part of the cured portion outside both ends in the width direction of the uncured portion where the energy ray curable resin is not cured, and cutting the outside of the cured portion, The material of the substrate is a thermoplastic resin elastomer, The substrate contains a urethane elastomer, The thickness of the substrate is 20 μm or more and 250 μm or less. The semiconductor processing adhesive sheet is used in a sheet expansion process in a semiconductor device manufacturing process, and the sheet expansion process is used to expand the intervals between a plurality of semiconductor chips. When an adherend is to be separated from the semiconductor processing adhesive sheet, the separation is performed by irradiating an energy ray to the adhesive layer. The tensile strength F of the adhesive sheet for semiconductor processing A1 and tensile strength F B1 The relationship satisfying the following mathematical formula (Mathematical formula 1A) is: F B1 / F A1 ≤30···(Mathematical formula 1A) The tensile strength F A1 The first test piece with a width of 25 mm is prepared from the semiconductor processing adhesive sheet corresponding to the uncured portion, the substrate and the uncured portion of the adhesive layer at both ends of the first test piece in the longitudinal direction are clamped with a clamp, and the tensile strength when stretched by 0.5 mm is measured using a tensile tester. The tensile strength F B1 The second test piece is made by clamping the substrate, the adhesive layer of the uncured portion, the first semiconductor chip and the second semiconductor chip at both ends of the second test piece in the longitudinal direction with a clamp, and using a tensile testing machine to measure the tensile strength when stretched by 0.5 mm. The second test piece is made by making the longitudinal dimension of the first semiconductor chip with a longitudinal dimension of 45 mm, the transverse dimension of 35 mm and the thickness of 0.625 mm and the longitudinal dimension of the second semiconductor chip with an edge of 45 mm along the longitudinal direction of the first test piece, setting the interval between the first semiconductor chip and the second semiconductor chip to 35 μm, and bonding the first semiconductor chip to the adhesive layer of the uncured portion at one end side of the longitudinal direction of the first test piece, and bonding the second semiconductor chip to the adhesive layer of the uncured portion at the other end side of the longitudinal direction of the first test piece.

10. The method for producing an adhesive sheet for semiconductor processing according to claim 9, wherein: The width of the cured portion remaining outside both ends of the uncured portion in the width direction is independently 0.5 mm or more.

11. The method for producing an adhesive sheet for semiconductor processing according to claim 9 or 10, wherein: After the step of cutting the outer side of the cured portion, there is further provided a step of winding the cut pressure-sensitive adhesive sheet for semiconductor processing into a roll.

12. The method for producing an adhesive sheet for semiconductor processing according to claim 9 or 10, wherein: The width of the cured portion is independently 0.5 mm or more and 10 mm or less.

13. The method for producing an adhesive sheet for semiconductor processing according to claim 9 or 10, wherein: The (meth)acrylate copolymer is a (meth)acrylate copolymer in which a functional group having energy ray curability is introduced into a side chain.

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