Method for manufacturing a semiconductor device

Abstract

The present application relates to a manufacturing method of a semiconductor device, which is a manufacturing method of a semiconductor device using an adhesive sheet having an adhesive layer (X1) containing a thermally expandable particle, a substrate (Y), and an adhesive layer (X2) which is cured by irradiation of energy rays to cause a reduction in adhesive force, in this order, and includes specific processes 1 to 5.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a semiconductor device. Background Technology

[0002] In recent years, the miniaturization, lightweighting, and high functionality of electronic devices have been developed. Along with this, there are also requirements for the miniaturization, thinning, and high density of the semiconductor devices carried by electronic devices.

[0003] In the manufacturing process of semiconductor devices, semiconductor wafers are processed into semiconductor chips through grinding processes to reduce their thickness and dicing processes to separate and dice them into individual wafers. At this time, the semiconductor wafers are subjected to given processing while being temporarily fixed to a temporary fixing sheet. After the semiconductor chips obtained from the given processing are separated from the temporary fixing sheet, they are subjected to wafer expansion processes to increase the spacing between the semiconductor chips as needed, rearrangement processes to arrange the multiple semiconductor chips with increased spacing, and flipping processes to flip the front and back sides of the semiconductor chips, and then they are mounted on a substrate.

[0004] When mounting semiconductor chips onto a substrate, a process is employed where the semiconductor chips are bonded to the substrate using a thermosetting film adhesive called a die-mount film (hereinafter also referred to as "DAF"). The DAF is bonded to one side of a semiconductor wafer or multiple monolithically assembled semiconductor chips, which are cut into the same shape as the semiconductor chips during or after the wafer is monolithically assembled. The monolithically assembled semiconductor chip with DAF is bonded to the substrate from the DAF side (die mounting), and then the semiconductor chip is bonded to the substrate by thermosetting the DAF. Therefore, the DAF needs to maintain its adhesive properties through pressure or heat until it is bonded to the substrate, thus requiring a process to achieve this.

[0005] To improve the machining accuracy and speed when grinding or assembling semiconductor wafers and other workpieces, it is necessary to use temporary fixing mechanisms such as temporary fixing plates to suppress vibrations and misalignments of the workpieces during machining. On the other hand, from the perspective of improving productivity, it is required that the workpieces can be quickly separated from the fixing mechanism after machining is completed.

[0006] Patent Document 1 discloses a method for cutting electronic components using a heat-release adhesive sheet for temporary fixation, in which a thermally expandable adhesive layer containing thermally expandable microspheres is provided on at least one side of a substrate. The document describes that this heat-release adhesive sheet ensures a given contact area with the adhered object during cutting of the electronic component, thus providing adhesion that prevents poor adhesion such as chip splashing. Furthermore, by heating after use to expand the thermally expandable microspheres, the contact area with the adhered object is reduced, thereby achieving easy peeling.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 3594853 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] However, when the workpiece is fixed to the thermally expandable adhesive layer and cut as disclosed in Patent Document 1, there is a risk that after peeling by heating, residues from thermally expandable particles may adhere to the surface of the workpiece, or the adhesive layer may deform or degenerate due to the expansion of the thermally expandable particles, causing part of the adhesive layer to adhere to the surface of the workpiece (so-called "residual adhesive"), thus contaminating the surface of the workpiece.

[0012] The present invention was made in view of the above-mentioned problems, and aims to provide a method for manufacturing a semiconductor device that eliminates the risk of contamination of the workpiece by thermally expanding particles and the expanded adhesive layer, and has excellent processability and productivity.

[0013] Problem Solving Methods

[0014] The inventors have discovered that the above-mentioned problems can be solved by using an adhesive sheet having an adhesive layer containing thermally expanding particles, a substrate, and an adhesive layer whose adhesive strength is reduced by curing it by irradiation with energy rays, and including specific steps 1 to 5.

[0015] That is, the present invention relates to the following [1] to

[10] .

[0016] [1] A method for manufacturing a semiconductor device, which is a method for manufacturing a semiconductor device using an adhesive sheet, the adhesive sheet having sequentially an adhesive layer (X1) containing thermally expanding particles, a substrate (Y), and an adhesive layer (X2) that is cured by irradiation with energy rays, thereby reducing adhesive strength.

[0017] This method includes the following steps 1 to 5:

[0018] Step 1: The process of attaching the object to be processed to the adhesive layer (X2) of the adhesive sheet and attaching the support to the adhesive layer (X1) of the adhesive sheet;

[0019] Step 2: A step involving performing one or more processing treatments on the above-mentioned workpiece, selected from grinding and single-piece processing;

[0020] Step 3: A step of attaching a thermosetting film to the side of the workpiece opposite to the adhesive layer (X2) after the above processing has been performed;

[0021] Step 4: The process of separating the adhesive layer (X1) and the support body by heating the adhesive sheet;

[0022] Step 5: A step of separating the adhesive layer (X2) from the object being processed by irradiating it with energy rays.

[0023] [2] The semiconductor device manufacturing method described in [1] above, wherein the above processing is a single-wafer processing based on the Stealth Dicing method, a grinding process and single-wafer processing based on the blade tip cutting method, or a grinding process and single-wafer processing based on the Stealth Dicing method.

[0024] [3] The manufacturing method of the semiconductor device according to [1] or [2] above, wherein the above processing is based on grinding processing and monolithic processing using stealth tip cutting method.

[0025] [4] The method for manufacturing a semiconductor device according to any one of [1] to [3] above, wherein the expansion initiation temperature (t) of the thermally expandable particles is 50 to 110°C.

[0026] [5] According to the semiconductor device manufacturing method described in [4] above, step 4 is a step of separating the adhesive layer (X1) and the support by heating the adhesive sheet to above and below the expansion initiation temperature (t) of the thermally expandable particles.

[0027] [6] In the method for manufacturing a semiconductor device according to any one of [1] to [5] above, the content of the thermally expandable particles is 1 to 30% by mass relative to the total mass (100% by mass) of the adhesive layer (X1).

[0028] [7] The method for manufacturing a semiconductor device according to any one of [1] to [6] above, wherein the average particle size (D) of the thermally expandable particles at 23°C is... 50 The range is 1–30 μm.

[0029] [8] The method for manufacturing a semiconductor device according to any one of [1] to [7] above, wherein the storage modulus E'(23) of the substrate (Y) at 23°C is 5.0 × 10⁻⁶. 7 ~5.0×10 9 Pa.

[0030] [9] The method for manufacturing a semiconductor device according to any one of [1] to [8] above, wherein the object of processing is a semiconductor wafer.

[0031]

[10] The method for manufacturing a semiconductor device according to any one of [1] to [9] above, wherein the energy ray is ultraviolet light.

[0032] The effects of the invention

[0033] According to the present invention, a method for manufacturing a semiconductor device can be provided that eliminates the risk of contamination of the workpiece by thermally expanding particles and the expanded adhesive layer, and has excellent processability and productivity. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view showing an example of the structure of the adhesive sheet of the present invention.

[0035] Figure 2 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0036] Figure 3 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0037] Figure 4 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0038] Figure 5 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0039] Figure 6 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0040] Figure 7 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0041] Figure 8 This is a cross-sectional view illustrating an example of the process of manufacturing a semiconductor device according to the present invention.

[0042] Symbol Explanation

[0043] 1a, 1b Adhesive sheets

[0044] 10a, 10b Stripping materials

[0045] 2. Support

[0046] 3. Laser irradiation device

[0047] 4 Modified regions

[0048] 5. Grinding machine

[0049] 6. Thermosetting films

[0050] 7 Support plates

[0051] W Semiconductor wafer

[0052] W1 Circuit plane of semiconductor wafers and semiconductor chips

[0053] The back of W2 semiconductor wafers and semiconductor chips

[0054] CP semiconductor chip

[0055] (X1) Adhesive layer (X1)

[0056] (X2) Adhesive layer (X2)

[0057] (Y) Substrate (Y) Detailed Implementation

[0058] In this specification, "active ingredient" refers to the component in the composition to be targeted, excluding the diluent.

[0059] Additionally, in this specification, the weight-average molecular weight (Mw) is a value converted to standard polystyrene by gel permeation chromatography (GPC), specifically a value determined based on the method described in the examples.

[0060] In this specification, for example, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and so on.

[0061] Furthermore, in this specification, the lower and upper limits of the preferred numerical ranges (e.g., the range of content, etc.) are described hierarchically and can be combined independently. For example, based on the description "preferred to be 10 to 90, more preferably 30 to 60", the "preferred lower limit (10)" and the "more preferably upper limit (60)" can be combined to obtain "10 to 60".

[0062] In this specification, "energy ray" refers to a ray containing energy quanta within an electromagnetic wave or a beam of charged particles. Examples of such rays include ultraviolet light, radiation, and electron beams. For instance, ultraviolet light sources such as electrodeless lamps, high-pressure mercury lamps, metal halide lamps, and UV-LEDs can be used to irradiate the target area. Regarding electron beams, electron beams generated by electron beam accelerators or similar devices can be used for irradiation.

[0063] In this specification, "energy-ray polymerizability" refers to the property of polymerization occurring when irradiated with energy rays.

[0064] In this specification, the determination of whether a “layer” is a “non-thermal expansion layer” or a “thermal expansion layer” is as described below.

[0065] If the layer being judged contains thermally expandable particles, the layer is heated for 3 minutes at the expansion initiation temperature (t) of the thermally expandable particles. If the volume change rate calculated by the following formula is less than 5%, the layer is judged as a "non-thermally expandable layer"; if it is more than 5%, the layer is judged as a "thermally expandable layer".

[0066] • Volume change rate (%) = {(Volume of the above layer after heat treatment - Volume of the above layer before heat treatment) / Volume of the above layer before heat treatment} × 100

[0067] It should be noted that layers that do not contain thermally expanding particles are considered "non-thermally expanding layers".

[0068] In this specification, the “surface” of a semiconductor wafer and semiconductor chip refers to the surface on which a circuit is formed (hereinafter also referred to as the “circuit surface”), and the “back side” of a semiconductor wafer and semiconductor chip refers to the surface on which no circuit is formed.

[0069] [Semiconductor device manufacturing method]

[0070] One aspect of the present invention is a method for manufacturing a semiconductor device using an adhesive sheet, the adhesive sheet comprising, in sequence, an adhesive layer (X1) containing thermally expanding particles, a substrate (Y), and an adhesive layer (X2) that is cured by irradiation with energy rays, thereby resulting in reduced adhesive strength.

[0071] This method includes the following steps 1 to 5:

[0072] Step 1: The process of attaching the object to be processed to the adhesive layer (X2) of the adhesive sheet and attaching the support to the adhesive layer (X1) of the adhesive sheet;

[0073] Step 2: A step involving performing one or more processing treatments on the above-mentioned workpiece, selected from grinding and single-piece processing;

[0074] Step 3: A step of attaching a thermosetting film to the side of the workpiece opposite to the adhesive layer (X2) after the above processing has been performed;

[0075] Step 4: The process of separating the adhesive layer (X1) and the support body by heating the adhesive sheet;

[0076] Step 5: A step of separating the adhesive layer (X2) from the object being processed by irradiating it with energy rays.

[0077] Here, in this specification, "semiconductor device" means any device capable of performing a function by utilizing the characteristics of semiconductors. Examples include: a wafer having an integrated circuit, a thinned wafer having an integrated circuit, a chip having an integrated circuit, a thinned chip having an integrated circuit, electronic components containing such chips, and electronic devices having such electronic components.

[0078] Furthermore, as a "processing object" that is processed in the manufacturing method of a semiconductor device according to one aspect of the present invention, semiconductor wafers and semiconductor chips can be representative examples, but there is no particular limitation as long as the processing object is applicable to the manufacturing method of the present invention.

[0079] According to one aspect of the semiconductor device manufacturing method of the present invention, the workpiece is processed in a state where it is bonded to an adhesive layer (X2) that will cure upon irradiation with energy rays, thereby reducing its adhesive strength. Using this method, after processing, the workpiece can be separated from the adhesive sheet by irradiating the adhesive layer (X2) with energy rays, thus preventing contamination of the workpiece by thermally expanding particles and the expanded adhesive layer.

[0080] In addition, according to one aspect of the semiconductor device manufacturing method of the present invention, when processing the workpiece, a support is attached to an adhesive layer (X1) containing thermally expanding particles.

[0081] The adhesive layer (X1) is a layer whose surface is formed by the expansion of thermally expandable particles (t) by heating it to a temperature above the expansion initiation temperature (t) of the thermally expandable particles, thereby reducing the contact area with the adhered object. Due to the reduced contact area, the adhesion between the adhesive layer (X1) and the adhered object is significantly reduced, allowing the adhesive sheet to be quickly separated from the support by its own weight or the weight of the adhered object, without the need for peeling force. For example, during heat peeling, the adhesive sheet with the object being processed can be tilted downwards, causing it to fall from the support due to gravity, thus separating the layers.

[0082] In this way, the adhesive layer (X1) is a layer whose adhesion to the support can be significantly reduced by heating, so the adhesion before heat peeling can be designed to be high. Therefore, when using the semiconductor device manufacturing method of one aspect of the present invention, vibration, misalignment, etc. of the workpiece caused by insufficient adhesion between the adhesive sheet and the support can be suppressed, and excellent processing accuracy and processing speed can be obtained.

[0083] It should be noted that, in this specification, the state in which the adhesive sheet can be peeled off from the adhered object without applying a peeling force is referred to as "self-peeling". Furthermore, this property is called "self-peelability".

[0084] Hereinafter, the adhesive sheet used in the manufacturing method of a semiconductor device according to one aspect of the present invention will be described first, and then the various steps included in the manufacturing method of a semiconductor device according to one aspect of the present invention will be described in detail.

[0085] [Adhesive sheet]

[0086] In one embodiment of the present invention, the adhesive sheet used is an adhesive sheet having, in sequence, an adhesive layer (X1) containing thermally expanding particles, a substrate (Y), and an adhesive layer (X2) that is cured by irradiation with energy rays, thereby resulting in a reduction in adhesive strength.

[0087] In one embodiment of the invention, the adhesive sheet may have a release material on the adhesive surface of one or both of the adhesive layers (X1) and (X2).

[0088] The composition of the adhesive sheet used in one embodiment of the present invention will now be described in more detail with reference to the accompanying drawings.

[0089] As an example of the adhesive sheet used in one aspect of the present invention, the following examples are cited: Figure 1 (a) shows a double-sided adhesive sheet 1a having a substrate (Y) sandwiched between adhesive layers (X1) and adhesive layers (X2).

[0090] Alternatively, it can also be formed as follows Figure 1 (b) shows a double-sided adhesive sheet 1b with a release material 10a on the adhesive surface of the adhesive layer (X1) and a release material 10b on the adhesive surface of the adhesive layer (X2).

[0091] It should be noted that, in Figure 1In the double-sided adhesive sheet 1b shown in (b), when the peeling force when peeling the release material 10a from the adhesive layer (X1) and the peeling force when peeling the release material 10b from the adhesive layer (X2) are equal, sometimes the adhesive layer is cut off and detached along with the release materials on both sides when trying to pull the release materials outwards to peel them off. From the viewpoint of suppressing this phenomenon, it is preferable to use two release materials 10a and 10b on both sides that are designed to have different peeling forces from the adhesive layers that are bonded to each other.

[0092] As an adhesive sheet in other ways, it can also be used in Figure 1 (a) The double-sided adhesive sheet 1a shown is a double-sided adhesive sheet formed by stacking peeling material on the adhesive surfaces of one of the adhesive layers (X1) and the adhesive layer (X2) and rolling it into a roll.

[0093] In one embodiment of the present invention, the adhesive sheet may or may not have other layers between the substrate (Y) and the adhesive layer (X1). Additionally, in another embodiment of the present invention, the adhesive sheet may or may not have other layers between the substrate (Y) and the adhesive layer (X2).

[0094] Preferably, a layer capable of suppressing expansion in the adhesive layer (X1) is directly laminated on the side opposite to the adhesive surface, and more preferably, a substrate (Y) is directly laminated thereon.

[0095] <Substrate (Y)>

[0096] Examples of materials that can be used to form the substrate (Y) include resin, metal, paper, etc., which may be appropriately selected depending on the purpose of the adhesive sheet used in one aspect of the invention.

[0097] Examples of resins include: polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; polyetheretherketone; polyethersulfone; polyphenylene sulfide; polyetherimide, polyimide, and other polyimide resins; polyamide resins; acrylic resins; and fluorinated resins.

[0098] Examples of metals include aluminum, tin, chromium, and titanium.

[0099] Examples of paper materials include: thin paper, medium-quality paper, high-quality paper, impregnated paper, coated paper, art paper, tracing paper, and cellophane.

[0100] Among these materials, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are preferred.

[0101] These forming materials can consist of one type or a combination of two or more.

[0102] Examples of substrates (Y) that use two or more forming materials in combination include: materials made by laminating paper with thermoplastic resins such as polyethylene, and materials on which a metal layer is formed on the surface of a resin film or sheet containing resin.

[0103] Examples of methods for forming a metal layer include: evaporating metal using PVD methods such as vacuum evaporation, sputtering, and ion plating; and bonding metal foil using conventional adhesives.

[0104] From the viewpoint of improving the interlayer adhesion between the substrate (Y) and the other layers stacked thereon, the surface of the substrate (Y) can be treated with surface treatments such as oxidation and texturing, easy-to-adhere treatments, and primer treatments.

[0105] Examples of oxidation methods include corona discharge treatment, plasma discharge treatment, wet chromic acid treatment, hot air treatment, ozone irradiation treatment, and ultraviolet irradiation treatment. Examples of surface treatment methods include sandblasting and solvent treatment.

[0106] The substrate (Y) may contain, in addition to the aforementioned resin, additives used as substrate materials, such as ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, and colorants. These substrate additives may be used individually or in combination of two or more.

[0107] When the substrate (Y) contains the above-mentioned resin and substrate additives, the content of each substrate additive is preferably 0.0001 to 20 parts by weight, more preferably 0.001 to 10 parts by weight, relative to 100 parts by weight of the above-mentioned resin.

[0108] The substrate (Y) is preferably a non-thermally expandable layer.

[0109] When the substrate (Y) is a non-thermally expandable layer, the volume change rate (%) of the substrate (Y) calculated by the above formula is less than 5%, preferably less than 2%, more preferably less than 1%, further preferably less than 0.1%, and even more preferably less than 0.01%.

[0110] Without departing from the scope of the present invention, the substrate (Y) may also contain thermally expandable particles, but preferably does not contain thermally expandable particles.

[0111] When the substrate (Y) contains thermally expandable particles, the lower the content, the better. Relative to the total mass (100% by mass) of the substrate (Y), it is preferably less than 3% by mass, more preferably less than 1% by mass, further preferably less than 0.1% by mass, even more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass.

[0112] [Physical properties of substrate (Y), etc.]

[0113] (Storage modulus E'(23) of substrate (Y) at 23°C)

[0114] The storage modulus E'(23) of the substrate (Y) at 23°C is preferably 5.0 × 10⁻⁶. 7 ~5.0×10 9 Pa, more preferably 5.0 × 10 8 ~4.5×10 9 Pa, more preferably 1.0 × 10 9 ~4.0×10 9 Pa.

[0115] The energy storage modulus E'(23) of the substrate (Y) is 5.0 × 10⁻⁶. 7 When Pa is above a certain value, it can effectively suppress the expansion of the substrate (Y) side of the adhesive layer (X1) and improve the deformation resistance of the adhesive sheet. On the other hand, the storage modulus E'(23) of the substrate (Y) is 5.0 × 10⁻⁶. 9 When the pressure is below Pa, the operability of the adhesive sheet can be improved.

[0116] It should be noted that, in this specification, the energy storage modulus E'(23) of the substrate (Y) represents the value measured by the method described in the examples.

[0117] (Storage modulus E'(t) of substrate (Y) at expansion initiation temperature (t))

[0118] The storage modulus E'(t) of the substrate (Y) at the expansion initiation temperature (t) of the thermally expanding particles is preferably 5.0 × 10⁻⁶. 6 ~4.0×10 9 Pa, more preferably 2.0 × 10 8 ~3.0×10 9 Pa, more preferably 5.0 × 10 8 ~2.5×10 9 Pa.

[0119] The storage modulus E'(t) of the substrate (Y) is 5.0 × 10⁻⁶. 6 When Pa is above a certain value, it can effectively suppress the expansion of the substrate (Y) side of the adhesive layer (X1) and improve the deformation resistance of the adhesive sheet. On the other hand, the storage modulus E'(t) of the substrate (Y) is 4.0 × 10⁻⁶. 9 When the pressure is below Pa, the operability of the adhesive sheet can be improved.

[0120] It should be noted that, in this specification, the storage modulus E'(t) of the substrate (Y) represents the value measured by the method described in the examples.

[0121] (Thickness of substrate (Y))

[0122] The thickness of the substrate (Y) is preferably 5 to 500 μm, more preferably 15 to 300 μm, and even more preferably 20 to 200 μm. When the thickness of the substrate (Y) is 5 μm or more, the deformation resistance of the adhesive sheet can be improved. On the other hand, when the thickness of the substrate (Y) is 500 μm or less, the operability of the adhesive sheet can be improved.

[0123] It should be noted that, in this specification, the thickness of the substrate (Y) represents a value measured by the method described in the examples.

[0124] <Adhesive layer (X1)>

[0125] The adhesive layer (X1) is an adhesive layer containing thermally expanding particles.

[0126] The adhesive layer (X1) is a layer whose surface is formed by the expansion of thermally expandable particles by heating it to above the expansion initiation temperature (t) of the thermally expandable particles, thereby reducing the adhesion to the adhered object.

[0127] The following describes the components contained in the adhesive layer (X1).

[0128] [Particles with thermal expansion]

[0129] The expansion initiation temperature (t) of the thermally expanding particles contained in the adhesive layer (X1) is not particularly limited, and can be appropriately selected according to the application of the adhesive sheet. For example, from the viewpoint of suppressing the expansion of thermally expanding particles caused by temperature rise during grinding or other processes on the workpiece, it is preferably 50°C or higher, more preferably 55°C or higher, further preferably 60°C or higher, and even more preferably 70°C or higher. On the other hand, from the viewpoint of suppressing the curing of the thermosetting film adhered to the workpiece during heat peeling, it is preferably 110°C or lower, more preferably 105°C or lower, further preferably 100°C or lower, and even more preferably 95°C or lower.

[0130] It should be noted that, in this specification, the expansion initiation temperature (t) of the thermally expandable particles represents a value determined based on the following method.

[0131] [Method for determining the expansion initiation temperature (t) of thermally expandable particles]

[0132] The sample was prepared by adding 0.5 mg of thermally expandable particles, which were to be measured, into an aluminum cup with a diameter of 6.0 mm (inner diameter of 5.65 mm) and a depth of 4.8 mm, and then covering it with an aluminum lid (diameter of 5.6 mm and thickness of 0.1 mm).

[0133] Using a dynamic viscoelasticity measuring device, the height of the sample was measured while a force of 0.01 N was applied to the sample from the top of the aluminum cap using an indenter. Then, while a force of 0.01 N was applied using the indenter, the sample was heated from 20 °C to 300 °C at a heating rate of 10 °C / min, and the displacement of the indenter in the vertical direction was measured. The initial temperature of the displacement in the positive direction was taken as the expansion initiation temperature (t).

[0134] As thermally expandable particles, microencapsulated foaming agents are preferred, comprising an outer shell formed of thermoplastic resin and an inner component encapsulated by the outer shell that vaporizes when heated to a given temperature.

[0135] There are no particular limitations on the thermoplastic resin that forms the outer shell of the microencapsulated foaming agent. It is sufficient to select materials and compositions that can undergo state changes such as melting, dissolving, and rupture at the expansion initiation temperature (t) of the thermally expandable particles.

[0136] Examples of the aforementioned thermoplastic resins include: vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, etc. These thermoplastic resins can be used alone or in combination of two or more.

[0137] As the component encapsulated within the shell of the microencapsulated foaming agent, i.e., the inner component, any component that expands at the initial expansion temperature (t) of the thermally expanding particles can be included. Examples include: propane, propylene, n-butane, butene, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, isobutane, isopentane, isohexane, isohexane, isohexane, isononane, isodecane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isodecadecane, cyclotridecane, hexylcyclohexane, tridecane, and tetradecane. Pentadecane, hexadecane, heptadecanane, octadecane, nonadecanane, isotridecanane, 4-methyldodecane, isotetradecane, isopentadecanane, isopentadecanane, isohexadecanane, 2,2,4,4,6,8,8-heptamethylnonane, isohexadecanane, isooctadecane, isononadecanane, 2,6,10,14-tetramethylpentadecanane, cyclotridecane, heptylcyclohexane, n-octylcyclohexane, cyclopentadecanane, nonylcyclohexane, decylcyclohexane, pentadecylcyclohexane, hexadecylcyclohexane, heptadecanylcyclohexane, octadecylcyclohexane, petroleum ether, etc. From the viewpoint of lowering the expansion initiation temperature (t) and suppressing the curing of the thermosetting film adhered to the workpiece when the adhesive layer (X1) is heated and peeled off, the following low-boiling-point liquids are preferred: propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, n-heptane, n-octane, cyclopropane, cyclobutane, petroleum ether, etc.

[0138] These encapsulated ingredients can be used alone or in combination of two or more.

[0139] The expansion initiation temperature (t) of thermally expandable particles can be adjusted by appropriately selecting the type of encapsulating component.

[0140] The average particle size (D) of thermally expandable particles at 23°C before thermal expansion. 50 The preferred size is 1–30 μm, more preferably 4–25 μm, further preferably 6–20 μm, and even more preferably 10–15 μm.

[0141] It should be noted that the average particle size (D) of thermally expandable particles 50 ) refers to the volume median particle size (D) 50 In the particle distribution of thermally expandable particles before expansion, as measured using a laser diffraction particle size distribution measuring device (e.g., Malvern, product name "Mastersizer 3000"), the cumulative volume frequency calculated starting from the smallest particle size corresponds to 50% of the particle size.

[0142] 90% of the particle size (D) of thermally expandable particles at 23°C before thermal expansion 90The preferred size is 2–60 μm, more preferably 8–50 μm, further preferably 12–40 μm, and even more preferably 20–30 μm.

[0143] It should be noted that 90% of the particle size (D) of thermally expandable particles 90 This refers to the cumulative volume frequency, calculated starting from the smallest particle size, of the thermally expandable particles before expansion, as measured using the aforementioned laser diffraction particle size distribution measuring device. This frequency corresponds to 90% of the particle size.

[0144] The maximum volume expansion rate when the thermally expandable particles are heated to a temperature above the expansion initiation temperature (t) is preferably 1.5 to 200 times, more preferably 2 to 150 times, further preferably 2.5 to 120 times, and even more preferably 3 to 100 times.

[0145] The content of thermally expandable particles is preferably 1 to 30% by mass, more preferably 2 to 25% by mass, and even more preferably 3 to 20% by mass, relative to the total mass (100% by mass) of the adhesive layer (X1).

[0146] When the content of thermally expandable particles is 1% by mass or more, there is a tendency for improved peelability during heat peeling. In addition, when the content of thermally expandable particles is 30% by mass or less, the adhesive force of the adhesive layer (X1) becomes good, and the tendency to suppress warping of the adhesive sheet during heat peeling is improved.

[0147] [Adhesive resin]

[0148] The adhesive resin contained in the adhesive layer (X1) can be selected according to the method of forming the adhesive layer (X1).

[0149] It should be noted that, in this invention, the term "adhesive resin" is also used broadly to include the concept of resins that are substantially composed of adhesive resins but do not have adhesive properties, but exhibit adhesive properties by adding plasticizing components or the like.

[0150] Examples of methods for forming the adhesive layer (X1) include: irradiating an energy ray with a polymeric composition containing an energy ray polymerizable component and thermally expandable particles (hereinafter also referred to as "polymeric composition (x-1A)") to form an adhesive layer (X1) containing the aforementioned energy ray polymerizable component and thermally expandable particles; and coating an adhesive composition containing an adhesive resin and thermally expandable particles (hereinafter also referred to as "adhesive composition (x-1B)") to form an adhesive layer (X1), etc.

[0151] Next, preferred methods for the adhesive resin in the methods using the polymeric composition (x-1A) and the adhesive composition (x-1B) will be described respectively.

[0152] -Method using polymerizable composition (x-1A)-

[0153] The method using the polymerizable composition (x-1A) is a method of forming an adhesive layer (X1) containing a polymer of the energy-ray polymerizable component and thermally expandable particles by irradiating the polymerizable composition (x-1A) containing energy-ray polymerizable components and thermally expandable particles with energy rays. Therefore, using this method, the adhesive resin contained in the adhesive layer (X1) becomes a polymer formed by polymerizing the energy-ray polymerizable component contained in the polymerizable composition (x-1A) with energy rays.

[0154] Since the polymerizable composition (x-1A) is a composition in which the energy-ray polymerizable components are polymerized to a high molecular weight through subsequent energy-ray polymerization, it can contain low molecular weight energy-ray polymerizable components when forming the layer. Therefore, for the polymerizable composition (x-1A), the viscosity suitable for coating can be adjusted without the use of solvents such as diluents. As a result, when forming the adhesive layer (X1) using the polymerizable composition (x-1A), the heating and drying process for removing solvents can be omitted, and unexpected expansion of thermally expandable particles during heating and drying can be suppressed. Furthermore, since it is not necessary to adjust the expansion initiation temperature (t) of the thermally expandable particles to above the heating and drying temperature, the expansion initiation temperature (t) of the thermally expandable particles can be lowered. Even when materials prone to thermal changes, such as semiconductor chips with DAF, are used as the adherend, thermal changes of the adherend caused by heating during heat peeling can be suppressed.

[0155] The polymerizable composition (x-1A) contains an energy-ray polymerizable component that polymerizes by irradiation with energy rays, and this component has energy-ray polymerizable functional groups.

[0156] Examples of functional groups that can polymerize with energy beams include (meth)acryloyl, vinyl, and allyl groups, which have carbon-carbon double bonds. It should be noted that in this specification, functional groups that partially contain vinyl or substituted vinyl groups, such as (meth)acryloyl and allyl, and vinyl or substituted vinyl groups themselves are sometimes collectively referred to as "vinyl-containing groups".

[0157] In the polymerizable composition (x-1A), it is preferable to contain a monomer (a1) having an energy-ray polymerizable functional group (hereinafter also referred to as "(a1) component") and a prepolymer (a2) having an energy-ray polymerizable functional group (hereinafter also referred to as "(a2) component") as an energy-ray polymerizable component.

[0158] It should be noted that, in this specification, a prepolymer refers to a compound that is polymerized from monomers and can be further polymerized to form a polymer.

[0159] (Single with energy-ray-aggregating functional groups (a1))

[0160] As a monomer (a1) with an energy-ray polymerizable functional group, it is acceptable to have any monomer with an energy-ray polymerizable functional group, or it may have a hydrocarbon group or other functional groups besides the energy-ray polymerizable functional group.

[0161] Examples of hydrocarbon groups present in component (a1) include aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these hydrocarbon groups.

[0162] Aliphatic hydrocarbon groups can be straight-chain or branched aliphatic hydrocarbon groups, or they can be alicyclic hydrocarbon groups.

[0163] Examples of aliphatic hydrocarbon groups with 1 to 20 carbon atoms include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, n-hexyl, 2-ethylhexyl, n-octyl, isooctyl, n-decyl, n-dodecyl, n-myristyl, n-palmityl, n-stearyl, etc.

[0164] Examples of alicyclic hydrocarbon groups include cyclopentyl, cyclohexyl, and isobornyl, which have 3 to 20 carbon atoms.

[0165] Examples of aromatic hydrocarbon groups include phenyl.

[0166] Examples of groups that combine aliphatic and aromatic hydrocarbon groups include phenoxyethyl and benzyl.

[0167] From the viewpoint of further improving the adhesive strength of the adhesive layer (X1), the (a1) component preferably contains monomers (a1-1) (hereinafter also referred to as "(a1-1) component") that have energy-ray polymerizable functional groups and straight-chain or branched aliphatic hydrocarbon groups, monomers (a1-2) (hereinafter also referred to as "(a1-2) component") that have energy-ray polymerizable functional groups and alicyclic hydrocarbon groups, etc.

[0168] When component (a1) contains component (a1-1), its content relative to the total (100% by mass) of component (a1) is preferably 20-80% by mass, more preferably 40-70% by mass, and even more preferably 50-60% by mass.

[0169] When component (a1) contains component (a1-2), its content relative to the total (100% by mass) of component (a1) is preferably 5 to 60% by mass, more preferably 10 to 40% by mass, and even more preferably 20 to 30% by mass.

[0170] Monomers having energy-ray polymerizable functional groups and functional groups other than energy-ray polymerizable functional groups can be exemplified by monomers having hydroxyl, carboxyl, thiohydroxy, primary amino, or secondary amino groups as functional groups other than energy-ray polymerizable functional groups. Among these functional groups, from the viewpoint of further improving the formability of the adhesive layer (X1), it is preferable that component (a1) contains monomers (a1-3) having energy-ray polymerizable functional groups and hydroxyl groups (hereinafter also referred to as "(a1-3) component").

[0171] When component (a1) contains components (a1-3), its content relative to the total (100% by mass) of component (a1) is preferably 1 to 60% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 20% by mass.

[0172] The number of energy-ray polymerizable functional groups in component (a1) can be one or more. In addition, from the viewpoint of further improving the self-peelability of the adhesive layer (X1), it is preferable that component (a1) contains monomers (a1-4) having three or more energy-ray polymerizable functional groups (hereinafter also referred to as "(a1-4) component").

[0173] When component (a1) contains components (a1-4), its content relative to the total (100% by mass) of component (a1) is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass.

[0174] As a monomer having one energy-ray polymerizable functional group, it is preferred to have one monomer containing a vinyl group (hereinafter also referred to as "polymerizable vinyl monomer").

[0175] As a monomer having two or more energy-ray polymerizable functional groups, a monomer having two or more (meth)acryloyl groups is preferred (hereinafter also referred to as "polyfunctional (meth)acrylate monomer"). By including the above-mentioned compounds in component (a1), the cohesiveness of the adhesive obtained by polymerization of them is improved, and an adhesive layer (X1) with less contamination from the adhered material after peeling can be formed.

[0176] Polymerizable Vinyl Monomers

[0177] As a polymerizable vinyl monomer, there are no special limitations as long as it has a vinyl group, and those previously known can be used appropriately.

[0178] Polymerizable vinyl monomers can be used alone or in combination of two or more.

[0179] Examples of polymerizable vinyl monomers include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, decyl methacrylate, dodecyl methacrylate, myristyl methacrylate, palmitate methacrylate, stearyl methacrylate, and other compounds corresponding to components (a1-1) above; cyclohexyl methacrylate, isobornyl methacrylate, and other compounds corresponding to components (a1-2) above; phenoxyethyl methacrylate, benzyl methacrylate, polyoxyethylene-modified methacrylate, and other methacrylates that do not have functional groups other than vinyl groups in their molecules. Among these, 2-ethylhexyl methacrylate and isobornyl methacrylate are preferred.

[0180] Polymerizable vinyl monomers may also be monomers that further have functional groups other than vinyl groups within the molecule. Examples of such functional groups include hydroxyl, carboxyl, thiohydroxy, primary amino, or secondary amino groups. Among these functional groups, polymerizable vinyl monomers having hydroxyl groups corresponding to the components described in (a1-3) above are preferred.

[0181] Examples of polymerizable vinyl monomers containing hydroxyl groups include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and other hydroxyalkyl (meth)acrylate esters; N-hydroxymethylacrylamide, N-hydroxymethylmethacrylamide, and other hydroxyacrylamides. Examples of polymerizable vinyl monomers containing carboxyl groups include: acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, and other olefinically unsaturated carboxylic acids. Among these monomers, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are preferred.

[0182] Other polymerizable vinyl monomers include, for example: vinyl esters such as vinyl acetate and vinyl propionate; olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; styrene monomers such as styrene and α-methylstyrene; diene monomers such as butadiene, isoprene, and chloroprene; nitrile monomers such as acrylonitrile and methacrylonitrile; amide monomers such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N,N-dimethyl(methyl)acrylamide, N,N-diethyl(methyl)acrylamide, and N-vinylpyrrolidone; and monomers containing tertiary amino groups such as N,N-diethylaminoethyl methacrylate and N-(meth)acryloylmorpholine.

[0183] Multifunctional (meth)acrylate monomers

[0184] As a polyfunctional (meth)acrylate monomer, there are no special limitations as long as it is a monomer with more than two (meth)acryloyl groups in one molecule, and those known in the past can be used appropriately.

[0185] Multifunctional (meth)acrylate monomers can be used alone or in combination of two or more.

[0186] Examples of multifunctional (meth)acrylate monomers include: 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol dimethacrylate, neopentyl glycol adipate dimethacrylate, neopentyl glycol dimethacrylate with hydroxypentanoic acid, dicyclopentyl dimethacrylate, caprolactone-modified dicyclopentyl dimethacrylate, ethylene oxide-modified dimethacrylate phosphate, di(acryloyloxyethyl)isocyanurate, allylated cyclohexyl dimethacrylate, and dimethacrylate modified with ethylene oxide isocyanurate, etc.; and difunctional (meth)acrylate monomers such as trimethylolpropane trimethacrylate and dipentaerythritol dimethacrylate. Tetraol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, bis(acryloyloxyethyl)hydroxyethyl isocyanurate, ethylene oxide modified isocyanurate triacrylate, ε-caprolactone modified tri(acryloyloxyethyl)isocyanurate, diglycerol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, propionic acid modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc., are polyfunctional (meth)acrylate monomers corresponding to the components (a1-4) above.

[0187] Content of component (a1)

[0188] The total content of polymerizable vinyl monomers in the polymerizable composition (x-1A) is preferably 10 to 80% by mass, more preferably 30 to 75% by mass, and even more preferably 50 to 70% by mass, relative to the total amount (100% by mass) of the active ingredient in the polymerizable composition (x-1A).

[0189] The total content of polyfunctional (meth)acrylate monomers in the polymeric composition (x-1A) is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 2 to 5% by mass, relative to the total amount (100% by mass) of the active ingredient in the polymeric composition (x-1A).

[0190] The total content of component (a1) in polymeric composition (x-1A) is preferably 15 to 90% by mass, more preferably 35 to 80% by mass, and even more preferably 55 to 75% by mass, relative to the total amount (100% by mass) of the active ingredient in polymeric composition (x-1A).

[0191] (a2) Prepolymer with energy-ray polymerizable functional groups

[0192] Examples of prepolymers (a2) having energy-ray polymerizable functional groups include prepolymers having one energy-ray polymerizable functional group and prepolymers having two or more energy-ray polymerizable functional groups. From the viewpoint of forming an adhesive layer with excellent self-peelability and minimal contamination from adhered material after peeling, component (a2) preferably contains a prepolymer having two or more energy-ray polymerizable functional groups, more preferably a prepolymer having two energy-ray polymerizable functional groups, and even more preferably a prepolymer having two energy-ray polymerizable functional groups, with these energy-ray polymerizable functional groups at both ends.

[0193] As component (a2), it is preferable to contain a prepolymer having two or more (meth)acryloyl groups as energy-ray polymerizable functional groups (hereinafter also referred to as "multifunctional (meth)acrylate prepolymer"). By including the above-mentioned compounds in component (a2), the cohesiveness of the adhesive obtained by polymerization of them is improved, and an adhesive layer (X1) with excellent self-peelability and minimal contamination of the adhered material after peeling can be formed.

[0194] Multifunctional (meth)acrylate prepolymers

[0195] As a multifunctional (meth)acrylate prepolymer, there are no special limitations as long as it is a prepolymer with more than two (meth)acryloyl groups in one molecule, and those previously known can be used appropriately.

[0196] Multifunctional (meth)acrylate prepolymers can be used alone or in combination of two or more.

[0197] Examples of multifunctional (meth)acrylate prepolymers include: urethane acrylate prepolymers, polyester acrylate prepolymers, epoxy acrylate prepolymers, polyether acrylate prepolymers, polybutadiene acrylate prepolymers, silicone acrylate prepolymers, and polyacrylamide acrylate prepolymers.

[0198] Carbamate acrylate prepolymers can be obtained by esterifying the following polyurethane prepolymers with (meth)acrylic acid or (meth)acrylic acid derivatives, for example by reacting polyisocyanates with compounds such as polyalkylene polyols, polyether polyols, polyester polyols, hydrogenated isoprene with hydroxyl terminals, and hydrogenated butadiene with hydroxyl terminals.

[0199] Examples of polyalkylene polyols that can be used in the manufacture of urethane acrylate prepolymers include polypropylene glycol, polyethylene glycol, polybutane glycol, and polyhexane glycol, among which polypropylene glycol is preferred. It should be noted that, when the number of functional groups in the resulting urethane acrylate prepolymer is to be three or more, appropriate combinations of ingredients such as glycerol, trimethylolpropane, triethanolamine, pentaerythritol, ethylenediamine, diethylenetriamine, sorbitol, and sucrose can be used.

[0200] Examples of polyisocyanates that can be used in the manufacture of urethane acrylate prepolymers include: aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylene diisocyanate; aromatic diisocyanates such as toluene diisocyanate, xylene diisocyanate, and diphenyl diisocyanate; and alicyclic diisocyanates such as dicyclohexylmethane diisocyanate and isophorone diisocyanate. Among these polyisocyanates, aliphatic diisocyanates are preferred, and hexamethylene diisocyanate is more preferred. It should be noted that polyisocyanates are not limited to bifunctional polyisocyanates; trifunctional or higher polyisocyanates can also be used.

[0201] Examples of (meth)acrylic acid derivatives that can be used in the manufacture of urethane acrylate prepolymers include: hydroxyethyl acrylate, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate; ethyl isocyanate acrylate, ethyl isocyanate methacrylate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate, etc. Among these (meth)acrylic acid derivatives, ethyl isocyanate is preferred.

[0202] Other methods for manufacturing urethane acrylate prepolymers include reacting the hydroxyl groups of compounds such as polyalkylene polyols, polyether polyols, polyester polyols, hydrogenated isoprene with hydroxyl-terminated ends, and hydrogenated butadiene with hydroxyl-terminated ends with the -N=C=O portion of (meth)acrylate isocyanate. In this case, the (meth)acrylate isocyanate can be, for example, 2-isocyanoethyl acrylate, 2-isocyanoethyl methacrylate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate, etc.

[0203] Polyester acrylate prepolymers can be obtained, for example, by esterifying the hydroxyl groups of a polyester prepolymer with hydroxyl groups at both ends, obtained by condensation of a polycarboxylic acid and a polyol, with (meth)acrylic acid. Alternatively, they can be obtained by esterifying the terminal hydroxyl groups of a prepolymer obtained by adding an olefin oxide to a polycarboxylic acid with (meth)acrylic acid.

[0204] Epoxy acrylate prepolymers can be obtained, for example, by reacting the epoxy rings of low molecular weight bisphenol-type epoxy resins, phenolic varnish-type epoxy resins, etc., with (meth)acrylic acid. Alternatively, carboxyl-modified epoxy acrylate prepolymers, which are obtained by partially modifying epoxy acrylate prepolymers with dicarboxylic anhydrides, can also be used.

[0205] Polyether acrylate prepolymers can be obtained, for example, by esterifying the hydroxyl groups of a polyether polyol with (meth)acrylic acid.

[0206] Polyacrylacrylate prepolymers can have acryl groups on the side chains, or they can have acryl groups at both ends or one end. Polyacrylacrylate prepolymers with acryl groups on the side chains can be obtained, for example, by adding glycidyl methacrylate to the carboxyl group of polyacrylic acid. Alternatively, polyacrylacrylate prepolymers with acryl groups at both ends can be obtained, for example, by polymerizing polyacrylate prepolymers synthesized via ATRP (Atom Transfer Radical Polymerization) to introduce acryl groups at both ends into a long-terminal structure.

[0207] (a2) The weight-average molecular weight (Mw) of the component is preferably 10,000 to 350,000, more preferably 15,000 to 200,000, and even more preferably 20,000 to 50,000.

[0208] Content of component (a2)

[0209] The total content of polyfunctional (meth)acrylate prepolymer in polymeric composition (x-1A) is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and even more preferably 20 to 30% by mass, relative to the total amount (100% by mass) of the active ingredient in polymeric composition (x-1A).

[0210] The total content of component (a2) in the polymeric composition (x-1A) is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, and even more preferably 20 to 30% by mass, relative to the total amount (100% by mass) of the active ingredient in the polymeric composition (x-1A).

[0211] Based on quality standards, the content ratio of component (a2) to component (a1) in the polymeric composition (x-1A) [(a2) / (a1)] is preferably 10 / 90 to 70 / 30, more preferably 20 / 80 to 50 / 50, and even more preferably 25 / 75 to 40 / 60.

[0212] Among the above-mentioned energy-ray polymerizable components, the preferred polymerizable composition (x-1A) contains polymerizable vinyl monomers, polyfunctional (meth)acrylate monomers, and polyfunctional (meth)acrylate prepolymers.

[0213] The total content of polymerizable vinyl monomers, polyfunctional (meth)acrylate monomers and polyfunctional (meth)acrylate prepolymers in the polymerizable composition (x-1A) relative to the total amount of energy-ray polymerizable components (100% by mass) is preferably 80% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and even more preferably 99% by mass or more, or may be 100% by mass.

[0214] The total content of the energy-ray polymerizable component is preferably 70-98% by mass, more preferably 75-97% by mass, further preferably 80-96% by mass, and even more preferably 82-95% by mass, relative to the total amount (100% by mass) of the active ingredient in the adhesive composition (x-1A) or the total mass (100% by mass) of the adhesive layer (X1).

[0215] The total content of the above-mentioned energy-ray polymerizable components can be interpreted as the content of the polymer formed by energy-ray polymerization of the energy-ray polymerizable components contained in the adhesive layer (X1).

[0216] (Particles with thermal expansion)

[0217] The preferred method for the thermally expandable particles contained in the polymeric composition (x-1A) is the same as the preferred method for the thermally expandable particles described above as a component contained in the adhesive layer (X1). The content of the thermally expandable particles relative to the total mass (100% by mass) of the adhesive layer (X1) can be understood alternatively as the content of the thermally expandable particles relative to the total amount (100% by mass) of the effective components of the polymeric composition (x-1A).

[0218] (Photopolymerization initiator)

[0219] From the viewpoint that the polymerization of the energy-ray polymerizable component can be carried out more efficiently, the polymerizable composition (x-1A) preferably contains a photopolymerization initiator.

[0220] Examples of photopolymerization initiators include: benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propane-1-one, and 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) Ketones, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzoin dimethyl ether, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligomer [2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, etc. Photopolymerization initiators can be used alone or in combination of two or more.

[0221] When the polymerizable composition (x-1A) contains a photopolymerization initiator, its content relative to 100 parts by weight of the energy ray polymerizable component is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, and even more preferably 0.3 to 1 part by weight.

[0222] When the content of the photopolymerization initiator is 0.1 parts by weight or more, the polymerization of the energy-ray polymerizable component can proceed more effectively. On the other hand, when the content is 10 parts by weight or less, unreacted and residual photopolymerization initiator can be eliminated or reduced, and the resulting adhesive layer (X1) can be easily adjusted to the desired physical properties.

[0223] (solvent)

[0224] It should be noted that the polymerizable composition (x-1A) may contain solvents such as diluents within a range that does not depart from the purpose of the present invention, but it is preferable to be solvent-free. That is, the polymerizable composition (x-1A) is preferably a solvent-free polymerizable composition.

[0225] By making the polymerizable composition (x-1A) a solvent-free polymerizable composition, the solvent-based heating and drying can be omitted when forming the adhesive layer (X1), thus suppressing the expansion of thermally expanding particles during heating and drying. Furthermore, when using solvents, thermally expanding particles sometimes exist unevenly on one side due to volume reduction during drying, leading to reduced adhesion to the substrate (Y) or decreased bonding strength of the adhesive surface. On the other hand, with a solvent-free polymerizable composition, polymerization can be carried out while maintaining the thermally expanding particles uniformly dispersed in the energy-ray polymerizable component to form the adhesive layer (X1), thus reducing the likelihood of the problems described above.

[0226] When the polymeric composition (x-1A) contains a solvent, the lower the content of the solvent, the better. The content of the solvent is preferably 10% by mass or less, more preferably 1% by mass or less, further preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less, relative to the total amount (100% by mass) of the active ingredient in the polymeric composition (x-1A).

[0227] The polymeric composition (x-1A) may also contain other components besides those described above. Examples of such other components include tackifiers and adhesive additives, which will be listed later.

[0228] (Method for manufacturing polymeric composition (x-1A))

[0229] The polymerizable composition (x-1A) can be manufactured by mixing an energy-ray polymerizable component, thermally expandable particles, and other components as needed. The resulting polymerizable composition (x-1A) is a composition in which the energy-ray polymerizable component is polymerized to a higher molecular weight through subsequent energy-ray polymerization. Therefore, during the formation of the layer, a suitable viscosity can be adjusted using a low molecular weight energy-ray polymerizable component. Thus, the polymerizable composition (x-1A) can be directly used as a coating solution for the formation of the adhesive layer (X1) without the addition of solvents such as diluents.

[0230] It should be noted that the adhesive layer (X1) formed by irradiating the polymeric composition (x-1A) with energy rays contains a variety of polymers polymerized by the energy ray polymeric components and thermally expandable particles dispersed in the polymers. However, in some cases, it is impossible or almost impractical to directly define them by their structure and physical properties.

[0231] -Method using adhesive composition (x-1B)-

[0232] The method of using the adhesive composition (x-1B) is a method of forming an adhesive layer (X1) by coating an adhesive composition (x-1B) containing an adhesive resin and thermally expandable particles. Using this method, the adhesive resin contained in the adhesive layer (X1) becomes the adhesive resin itself contained in the adhesive composition (x-1B).

[0233] The adhesive composition (x-1B) is a composition containing an adhesive resin and thermally expandable particles.

[0234] The following describes each component contained in the adhesive composition (x-1B).

[0235] The preferred method for the thermally expandable particles contained in the adhesive composition (x-1B) is the same as the preferred method for the thermally expandable particles described above as a component contained in the adhesive layer (X1). The content of the thermally expandable particles relative to the total mass (100% by mass) of the adhesive layer (X1) can be understood alternatively as the content of the thermally expandable particles relative to the total amount (100% by mass) of the effective components of the adhesive composition (x-1B).

[0236] As the adhesive resin contained in the adhesive composition (x-1B), it can be any polymer that has adhesive properties on its own and has a weight-average molecular weight (Mw) of 10,000 or more.

[0237] From the viewpoint of improving adhesive strength, the weight-average molecular weight (Mw) of the adhesive resin is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,500,000, and even more preferably 30,000 to 1,000,000.

[0238] Examples of specific adhesive resins include, for example, acrylic resins, urethane resins, rubber resins such as polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. Among these, acrylic resins are preferred from the viewpoint of exhibiting excellent adhesive strength and from the viewpoint of easily forming an uneven surface on the formed adhesive layer by utilizing the expansion of thermally expanding particles based on heat treatment.

[0239] These adhesive resins can be used alone or in combination of two or more.

[0240] In addition, when these adhesive resins are copolymers having two or more structural units, the form of the copolymer is not particularly limited and can be any form of block copolymer, random copolymer, or graft copolymer.

[0241] The content of adhesive resin is preferably 30 to 99.99% by mass, more preferably 40 to 99.95% by mass, further preferably 50 to 99.90% by mass, even more preferably 55 to 99.80% by mass, and even more preferably 60 to 99.50% by mass, relative to the total amount (100% by mass) of the active ingredient in the adhesive composition (x-1B) or the total mass (100% by mass) of the adhesive layer (X1).

[0242] The adhesive composition (x-1B) may also contain other components besides those described above. Examples of other components include solvents, tackifiers (described later), and adhesive additives.

[0243] The adhesive composition (x-1B) can be manufactured by adding an adhesive resin, other components as needed, etc.

[0244] [Other ingredients]

[0245] The adhesive layer (X1) may also contain other components besides adhesive resin and thermally expandable particles.

[0246] Other components mentioned above include: tackifiers, adhesive additives that are commonly used in adhesives and other than those mentioned above.

[0247] (Thickening agent)

[0248] Tackifiers are components used as needed to further improve adhesive strength.

[0249] In this specification, "tackifier" refers to a component with a weight-average molecular weight (Mw) of less than 10,000, which is distinct from adhesive resins.

[0250] The tackifier has a weight-average molecular weight (Mw) of less than 10,000, preferably 400 to 9,000, more preferably 500 to 8,000, and even more preferably 800 to 5,000.

[0251] Examples of tackifiers include: rosin resins, terpene resins, styrene resins, C5 petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by the thermal decomposition of naphtha, C9 petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene produced by the thermal decomposition of naphtha, and hydrogenated resins obtained by hydrogenation of these resins.

[0252] The softening point of the tackifier is preferably 60–170°C, more preferably 65–160°C, and even more preferably 70–150°C.

[0253] It should be noted that in this specification, the “softening point” of the tackifier is a value measured based on JIS K 2531.

[0254] Tackifiers can be used alone, or two or more with different softening points, structures, etc., can be used in combination. When using two or more tackifiers, it is preferable that the weighted average of the softening points of these multiple tackifiers falls within the above-mentioned range.

[0255] When the adhesive layer (X1) contains a tackifier, its content relative to the total mass (100% by mass) of the adhesive layer (X1) is preferably 0.01 to 65% by mass, more preferably 0.1 to 50% by mass, further preferably 1 to 40% by mass, and even more preferably 2 to 30% by mass.

[0256] (Additives for adhesives)

[0257] Examples of adhesive additives include: silane coupling agents, antioxidants, plasticizers, rust inhibitors, pigments, dyes, retardants, reaction accelerators (catalysts), and ultraviolet absorbers. These adhesive additives can be used individually or in combination of two or more.

[0258] When the adhesive layer (X1) contains adhesive additives, the content of each adhesive additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, relative to the total mass (100% by mass) of the adhesive layer (X1).

[0259] [Physical properties of the adhesive layer (X1), etc.]

[0260] (Adhesive layer (X1) at 23°C before thermal expansion)

[0261] The adhesive strength of the adhesive layer (X1) at 23°C before thermal expansion is preferably 0.1 to 12.0 N / 25 mm, more preferably 0.5 to 9.0 N / 25 mm, further preferably 1.0 to 8.0 N / 25 mm, and even more preferably 1.2 to 7.5 N / 25 mm.

[0262] When the adhesive layer (X1) has an adhesive force of 0.1 N / 25 mm or more at 23°C before thermal expansion, it can more effectively suppress unexpected peeling and misalignment of the adhered object during temporary fixation. On the other hand, when the adhesive force is 12.0 N / 25 mm or less, the peelability during heat peeling can be further improved.

[0263] It should be noted that, in this specification, the adhesive force of the adhesive layer refers to the adhesive force relative to the mirror surface of the silicon mirror wafer.

[0264] In addition, in this specification, the adhesive strength of the adhesive layer (X1) at 23°C before thermal expansion specifically refers to the value measured by the method described in the examples.

[0265] (Adhesive strength of adhesive layer (X1) at 23°C after thermal expansion)

[0266] The adhesive layer (X1) has an adhesive strength of 1.5 N / 25 mm or less after thermal expansion at 23°C, more preferably 0.05 N / 25 mm or less, further preferably 0.01 N / 25 mm or less, and even more preferably 0 N / 25 mm. It should be noted that an adhesive strength of 0 N / 25 mm refers to an adhesive strength below the test limit in the method for measuring the adhesive strength at 23°C after thermal expansion described later, and also includes cases where the adhesive strength is too low and peeling occurs unexpectedly during the fixing of the adhesive sheet for testing.

[0267] In this specification, the adhesive strength of the adhesive layer (X1) at 23°C after thermal expansion specifically refers to the value measured by the method described in the examples.

[0268] (Shear storage modulus G'(23) of adhesive layer (X1) at 23°C)

[0269] The shear storage modulus G'(23) of the adhesive layer (X1) at 23°C is preferably 1.0 × 10⁻⁶. 4 ~5.0×10 7 Pa, more preferably 5.0 × 10 4 ~1.0×10 7 Pa, more preferably 1.0 × 10 5 ~5.0×10 6 Pa.

[0270] The shear storage modulus G'(23) of the adhesive layer (X1) is 1.0 × 10⁻⁶. 4 When Pa is above a certain value, it can suppress the misalignment of the adhered object during temporary fixation and the excessive sinking of the adhered object into the adhesive layer (X1). On the other hand, the shear storage modulus G'(23) is 5.0 × 10⁻⁶. 7 When Pa is below, there is a tendency for unevenness to form on the surface of the adhesive layer (X1) due to the expansion of thermally expandable particles, thereby improving the peelability during heat peeling.

[0271] It should be noted that, in this specification, the shear storage modulus G'(23) of the adhesive layer (X1) at 23°C represents the value measured by the method described in the examples.

[0272] The adhesive layer (X1) is a layer containing thermally expandable particles, and the shear storage modulus G' of the adhesive layer (X1) may be affected by the thermally expandable particles. From the viewpoint of measuring the shear storage modulus G' after excluding the influence of thermally expandable particles, it is possible to prepare an adhesive layer (hereinafter also referred to as "non-expandable adhesive layer (X1')") with the same composition as the adhesive layer (X1) except that it does not contain thermally expandable particles, and to measure the shear storage modulus G' of this adhesive layer.

[0273] (Shear storage modulus G'(23) of the non-expanding adhesive layer (X1') at 23°C)

[0274] The shear storage modulus G'(23) of the non-expanding adhesive layer (X1') at 23°C is preferably 1.0 × 10⁻⁶. 4 ~5.0×10 7 Pa, more preferably 5.0 × 10 4 ~1.0×10 7 Pa, more preferably 1.0 × 10 5 ~5.0×10 6 Pa.

[0275] The shear storage modulus G'(23) of the non-expanding adhesive layer (X1') is 1.0 × 10⁻⁶. 4 When Pa is above a certain value, it can suppress the misalignment of the adhered object during temporary fixation and the excessive sinking of the adhered object into the adhesive layer (X1). On the other hand, the shear storage modulus G'(23) is 5.0 × 10⁻⁶. 7 When Pa is below, there is a tendency for unevenness to form on the surface of the adhesive layer (X1) due to the expansion of thermally expandable particles, thereby improving the peelability during heat peeling.

[0276] (Shear storage modulus G'(t) of the non-expanding adhesive layer (X1') at the expansion initiation temperature (t))

[0277] The shear storage modulus G'(t) of the non-expanding adhesive layer (X1') at the expansion initiation temperature (t) of the aforementioned thermally expandable particles is preferably 5.0 × 10⁻⁶. 3 ~1.0×10 7 Pa, more preferably 1.0 × 10 4 ~5.0×10 6 Pa, more preferably 5.0 × 10 4 ~1.0×10 6 Pa.

[0278] The shear storage modulus G'(t) of the non-expanding adhesive layer (X1') is 5.0 × 10⁻⁶. 3At Pa or higher, it can suppress misalignment of the adhered material during temporary fixation and excessive embedding of the adhered material into the adhesive layer (X1), while also suppressing warping of the adhesive sheet during heat peeling, thereby improving operability. On the other hand, the shear storage modulus G'(t) is 1.0 × 10⁻⁶. 7 When Pa is below, there is a tendency for unevenness to form on the surface of the adhesive layer (X1) due to the expansion of thermally expandable particles, thereby improving the peelability during heat peeling.

[0279] It should be noted that, in this specification, the shear storage modulus G' of the non-expanding adhesive layer (X1') at a given temperature represents a value measured by the method described in the examples.

[0280] (Thickness of adhesive layer (X1) at 23°C)

[0281] The thickness of the adhesive layer (X1) at 23°C is preferably 5 to 150 μm, more preferably 10 to 100 μm, and even more preferably 20 to 80 μm.

[0282] When the adhesive layer (X1) has a thickness of 5 μm or more at 23°C, it is easy to obtain sufficient adhesive force, which can suppress the tendency for unexpected peeling or misalignment of the adhered object during temporary fixation. On the other hand, when the thickness of the adhesive layer (X1) at 23°C is 150 μm or less, the peelability during heat peeling is improved, and the warping of the adhesive sheet during heat peeling is suppressed, thereby improving operability.

[0283] It should be noted that, in this specification, the thickness of the adhesive layer represents a value measured by the method described in the examples. Furthermore, the thickness of the adhesive layer (X1) is the value before the thermally expanding particles expand.

[0284] <Adhesive layer (X2)>

[0285] The adhesive layer (X2) is an adhesive layer that is cured by irradiation with energy rays, resulting in a decrease in adhesive strength.

[0286] In one embodiment of the present invention, the adhesive layer used for bonding the workpiece is an adhesive layer (X2) that is cured by irradiation with energy rays, thereby reducing its adhesive strength. This prevents contamination of the workpiece surface due to thermally expanding particles and the expanded adhesive layer when the workpiece is peeled off the adhesive layer. Furthermore, by using different mechanisms for reducing the adhesive strength of adhesive layers (X1) and (X2), it is possible to prevent unintentional reduction of the adhesive strength of the other adhesive layer when reducing the adhesive strength of either layer.

[0287] The adhesive layer (X2) is preferably a non-thermally expandable layer, and the volume change rate (%) of the adhesive layer (X2) calculated by the above formula is less than 5%, preferably less than 2%, more preferably less than 1%, further preferably less than 0.1%, and even more preferably less than 0.01%.

[0288] The adhesive layer (X2) is preferably free of thermally expanding particles, but may contain thermally expanding particles to a extent that does not depart from the purpose of the invention.

[0289] When the adhesive layer (X2) contains thermally expandable particles, the lower the content, the better. It is preferably less than 3% by mass, more preferably less than 1% by mass, further preferably less than 0.1% by mass, even more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass relative to the total mass (100% by mass) of the adhesive layer (X2).

[0290] The adhesive layer (X2) is preferably formed from an energy-curable adhesive composition (x-2) (hereinafter also simply referred to as "adhesive composition (x-2)").

[0291] By forming from the adhesive composition (x-2), the adhesive layer (X2) can be made into an adhesive layer that will be cured by energy ray irradiation, resulting in a decrease in adhesive strength.

[0292] The following describes each component contained in the adhesive composition (x-2).

[0293] Examples of energy-curable adhesive compositions (x-2) include: an adhesive composition (x-2A) that contains an energy-curable low-molecular-weight compound in addition to a non-energy-curable adhesive resin (I) (hereinafter also referred to as "adhesive resin (I)"), or an adhesive composition (x-2B) that contains an energy-curable adhesive resin (II) (hereinafter also referred to as "adhesive resin (II)") whose side chains are incorporating unsaturated groups.

[0294] [Non-energy radiation curable adhesive resin (I)]

[0295] The weight-average molecular weight (Mw) of the non-energy-curable adhesive resin (I) is preferably 250,000 to 1,500,000, more preferably 350,000 to 1,300,000, further preferably 450,000 to 1,100,000, and even more preferably 650,000 to 1,050,000.

[0296] Examples of non-energy-curable adhesive resins (I) include acrylic resins, rubber resins, and silicone resins. Among these, acrylic resins are preferred.

[0297] The following is a detailed explanation of acrylic resins.

[0298] (Acrylic resins)

[0299] As an acrylic resin, a resin containing a structural unit (p1) derived from an alkyl (meth)acrylate monomer (hereinafter also referred to as "monomer (p1)") having 4 or more carbon atoms is preferred.

[0300] Acrylic resins may also be homopolymers consisting only of structural units (p1) derived from monomers (p1) as described above, but preferably copolymers that further contain structural units (p2) derived from alkyl (meth)acrylate monomers (hereinafter also referred to as "monomers (p2)") having 1 to 3 carbon atoms and / or structural units (p3) derived from functionalized monomers (p3) (hereinafter also referred to as "monomers (p3)").

[0301] From the viewpoint of improving the adhesive strength of the adhesive layer (X2), the number of carbon atoms of the alkyl group in the monomer (p1) is preferably 4 to 20, more preferably 4 to 12, and even more preferably 4 to 6. Furthermore, the alkyl group in the monomer (p1) can be any alkyl group, whether straight-chain or branched.

[0302] Examples of monomers (p1) include: butyl methacrylate, pentyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, etc.

[0303] It should be noted that these monomers (p1) can be used alone or in combination of two or more.

[0304] Of these monomers, butyl (meth)acrylate is preferred from the viewpoint of improving the adhesive strength of the adhesive layer (X2).

[0305] When the acrylic resin is a copolymer, the content of structural unit (p1) relative to all structural units of the acrylic resin is preferably 40 to 98% by mass, more preferably 45 to 95% by mass, and even more preferably 50 to 90% by mass.

[0306] Examples of monomers (p2) include methyl methacrylate, ethyl methacrylate, and propyl methacrylate.

[0307] It should be noted that these monomers (p2) can be used alone or in combination of two or more.

[0308] Among these monomers, methyl methacrylate is preferred.

[0309] When the acrylic resin is a copolymer, the content of structural unit (p2) relative to all structural units of the acrylic resin is preferably 1 to 30% by mass, more preferably 3 to 26% by mass, and even more preferably 6 to 22% by mass.

[0310] Monomer (p3) refers to a monomer having a functional group that can react with the crosslinking agent described later to become a crosslinking initiation point or a functional group that has a crosslinking promoting effect.

[0311] Examples of functional groups present in monomers (p3) include hydroxyl, carboxyl, amino, and epoxy groups. Among these functional groups, carboxyl or hydroxyl groups are preferred from the viewpoint of reactivity with crosslinking agents.

[0312] Examples of monomers (p3) include: hydroxyl-containing monomers, carboxyl-containing monomers, amino-containing monomers, and epoxy-containing monomers.

[0313] These monomers (p3) can be used alone or in combination of two or more.

[0314] Among these monomers, hydroxyl-containing monomers and carboxyl-containing monomers are preferred, and hydroxyl-containing monomers are even more preferred.

[0315] Examples of hydroxyl-containing monomers include: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, and other hydroxyalkyl methacrylates; unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[0316] Examples of carboxyl-containing monomers include: (meth)acrylic acid, crotonic acid and other olefinic unsaturated monocarboxylic acids; fumaric acid, itaconic acid, maleic acid, citraconic acid and other olefinic unsaturated dicarboxylic acids and their anhydrides; 2-carboxyethyl methacrylate, etc.

[0317] When the acrylic resin is a copolymer, the content of structural unit (p3) relative to all structural units of the acrylic resin is preferably 1 to 35% by mass, more preferably 3 to 32% by mass, and even more preferably 6 to 30% by mass.

[0318] In addition, acrylic resins may also contain structural units derived from monomers capable of copolymerizing with acrylic monomers, other than the structural units (p1) to (p3) mentioned above. Examples of such monomers include: styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0319] [Energy-curable adhesive resin (II)]

[0320] Adhesive resin (II) is an energy-curable adhesive resin in which unsaturated groups are introduced into the side chains of the above-mentioned non-energy-curable adhesive resin (I).

[0321] The weight-average molecular weight (Mw) of the energy-curable adhesive resin (II) with unsaturated groups introduced into its side chains is preferably 300,000 to 1,600,000, more preferably 400,000 to 1,400,000, further preferably 500,000 to 1,200,000, and even more preferably 700,000 to 1,100,000.

[0322] As the main chain of the adhesive resin (II), the adhesive resin (I) described above can be used, but an acrylic resin is preferred, and an acrylic copolymer having structural units (p1), (p2) and (p3) is more preferred.

[0323] Unsaturated groups present in the side chains of adhesive resin (II) include (meth)acryloyl, vinyl, allyl, etc., with (meth)acryloyl being preferred.

[0324] The synthesis of adhesive resin (II) can be exemplified by the following method: a functional group is copolymerized with an adhesive resin (I) to form a functional group, a compound having both a substituent and an unsaturated group that can bind to the functional group is added, and the functional group of the copolymer is bound to the substituent to obtain adhesive resin (II).

[0325] As functionalized monomers copolymerized with adhesive resin (I), the compounds listed above as monomers (p3) can be cited.

[0326] Examples of substituents that can bind to this functional group include isocyanate groups and glycidyl groups.

[0327] Therefore, examples of compounds having both substituents and unsaturated groups that can bind to this functional group include (meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and (meth)acrylate glycidyl ester.

[0328] [Cross-linking agent]

[0329] The adhesive compositions (x-2A) and (x-2B) preferably further contain a crosslinking agent.

[0330] The main purpose of adding a crosslinking agent is to react with the functional groups in the side chains of the non-energy-curable adhesive resin (I) or energy-curable adhesive resin (II) of the acrylic resin, which are derived from the monomer (p3), thereby crosslinking the adhesive resins with each other.

[0331] Examples of crosslinking agents include: isocyanate crosslinking agents such as toluene diisocyanate, hexamethylene diisocyanate, and their adducts; epoxy crosslinking agents such as ethylene glycol glycidyl ether; aziridine crosslinking agents such as hexa[1-(2-methyl)-aziridinyl]triazine triphosphate; chelate crosslinking agents such as aluminum chelates; and so on. These crosslinking agents can be used alone or in combination of two or more.

[0332] Among these crosslinking agents, isocyanate-based crosslinking agents are preferred from the viewpoints of improving cohesion and thus adhesion, as well as ease of availability.

[0333] The amount of crosslinking agent can be appropriately selected according to the number of functional groups in the structure of adhesive resins (I) and (II), but from the viewpoint of promoting the crosslinking reaction, it is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 4 parts by mass relative to 100 parts by mass of adhesive resins (I) and (II).

[0334] [Photopolymerization initiator]

[0335] Furthermore, the adhesive compositions (x-2A) and (x-2B) preferably further contain a photopolymerization initiator. By containing a photopolymerization initiator, the curing reaction can be fully carried out even by low-energy rays such as ultraviolet light.

[0336] Examples of photopolymerization initiators include: 1-hydroxy-cyclohexyl-phenyl-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, dimethyl ethyl ketone, 8-chloroanthraquinone, etc.

[0337] These photopolymerization initiators can be used alone or in combination of two or more.

[0338] The amount of photopolymerization initiator is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, and even more preferably 0.05 to 2 parts by weight, relative to 100 parts by weight of adhesive resins (I) and (II).

[0339] [Other Additives]

[0340] Other additives may also be included in the adhesive compositions (x-2A) and (x-2B) without compromising the effects of the present invention.

[0341] Other additives may include those that are the same as the tackifiers and adhesive additives optionally contained in the adhesive layer (X1), preferably in the same manner and amount.

[0342] In addition, from the viewpoint of improving the coatability relative to the substrate, release sheet, etc., the adhesive compositions (x-2A) and (x-2B) can also be diluted with a solvent to form a solution.

[0343] Examples of solvents include: methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, and dimethyl ethyl ketone. Alkane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol, etc.

[0344] It should be noted that these solvents can be the same solvents used in generating adhesive resins (I) and (II), or one or more solvents other than those used in preparation can be added to the solution of the adhesive composition in order to uniformly coat it.

[0345] When diluting the adhesive compositions (x-2A) and (x-2B) with a solvent, it is preferable to formulate the solvent in such a way that the concentration of its solid components reaches a preferred concentration of 5 to 60% by mass, more preferably 10 to 45% by mass, and even more preferably 15 to 30% by mass.

[0346] The adhesive composition (x-2) can be manufactured by mixing an adhesive resin, a crosslinking agent as needed, a photopolymerization initiator, and other additives.

[0347] [Physical properties of the adhesive layer (X2), etc.]

[0348] (Adhesive strength of adhesive layer (X2))

[0349] The adhesive force of the adhesive surface of the adhesive layer (X2) before irradiation by energy rays is preferably 4.0 to 30.0 N / 25 mm, more preferably 6.0 to 27.0 N / 25 mm, further preferably 8.0 to 24.0 N / 25 mm, and even more preferably 10.0 to 20.0 N / 25 mm.

[0350] When the adhesive force of the adhesive layer (X2) before energy ray irradiation is 4.0 N / 25 mm or more, it can more effectively suppress unexpected peeling from the adhered object and misalignment of the adhered object during temporary fixation. On the other hand, when the adhesive force is 30.0 N / 25 mm or less, the adhesive force after energy ray irradiation can be suppressed to a low level.

[0351] The adhesive force of the adhesive surface of the adhesive layer (X2) after irradiation by energy rays is preferably 0.01 to 2.0 N / 25 mm, more preferably 0.02 to 1.0 N / 25 mm, further preferably 0.03 to 0.50 N / 25 mm, and even more preferably 0.05 to 0.30 N / 25 mm.

[0352] When the adhesive surface of the adhesive layer (X2) has an adhesive force of 0.01 N / 25 mm or more after energy ray irradiation, it can effectively suppress the unexpected detachment of the workpiece during the process. On the other hand, when the adhesive force is 2.0 N / 25 mm or less, it is easy to peel off without causing damage to the adhered object.

[0353] (Shear storage modulus G'(23) of adhesive layer (X2) at 23°C)

[0354] The shear storage modulus G'(23) of the adhesive layer (X2) at 23°C is preferably 5.0 × 10⁻⁶. 3 ~1.0×10 7 Pa, more preferably 1.0 × 10 4 ~5.0×10 6 Pa, more preferably 5.0 × 10 4 ~1.0×10 6 Pa.

[0355] The shear storage modulus G'(23) of the adhesive layer (X2) is 5.0 × 10⁻⁶. 3 When Pa is above a certain value, there is a tendency to suppress the misalignment of the adhered object during temporary fixation and the excessive sinking of the adhered object into the adhesive layer (X2). On the other hand, the shear storage modulus G'(23) is 1.0 × 10⁻⁶. 7 When the pressure is below a certain level, there is a tendency for increased adhesion to the adhered object.

[0356] It should be noted that, in this specification, the shear storage modulus G'(23) of the adhesive layer (X2) at 23°C can be determined using the same method as that used for the shear storage modulus G' of the adhesive layer (X1) at 23°C.

[0357] (Thickness of adhesive layer (X2) at 23°C)

[0358] The thickness of the adhesive layer (X2) at 23°C is preferably 5–150 μm, more preferably 8–100 μm, further preferably 12–70 μm, and even more preferably 15–50 μm.

[0359] When the adhesive layer (X2) is 5 μm or thicker at 23°C, sufficient adhesive force is easily obtained, and there is a tendency to suppress unexpected peeling or misalignment of the adhered object during temporary fixation. On the other hand, when the adhesive layer (X2) is 150 μm or less thick at 23°C, the operation of the adhesive sheet tends to become easier.

[0360] <Removal Material>

[0361] As a release material, release sheets that have undergone double-sided release treatment or single-sided release treatment can be used, and materials in which a release agent is coated on the substrate of the release material can be used.

[0362] Examples of substrates used as release materials include plastic films and paper. Examples of plastic films include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; and olefin resin films such as polypropylene resin and polyethylene resin. Examples of paper include high-quality paper, cellophane, and kraft paper.

[0363] Examples of release agents include: silicone resins, olefin resins, isoprene resins, butadiene resins, and other rubber elastomers; long-chain alkyl resins, alkyd resins, fluoropolymers, etc. A release agent can be used alone or in combination with two or more other agents.

[0364] The thickness of the release material is preferably 10–200 μm, more preferably 20–150 μm, and even more preferably 35–80 μm.

[0365] <Method for manufacturing adhesive sheet>

[0366] In one embodiment of the present invention, the method for manufacturing the adhesive sheet is preferably a method that appropriately selects the type of material used.

[0367] Hereinafter, a method for manufacturing an adhesive sheet that uses the above-described polymeric composition (x-1A) or adhesive composition (x-1B) to form an adhesive layer (X1) will be described, but the method for manufacturing the adhesive sheet used in one embodiment of the present invention is not limited to these methods.

[0368] -Method using polymerizable composition (x-1A)-

[0369] When a polymeric composition (x-1A) is used in the formation of the adhesive layer (X1), the adhesive sheet used in one aspect of the invention is preferably manufactured by a method comprising a step of irradiating the polymeric composition (x-1A) with energy rays to form a polymer of the energy-ray polymeric component. More specifically, the method preferably includes steps IA to IIIA described below.

[0370] Process IA: A process of forming a polymeric composition layer (x-1A) on one side of a substrate (Y);

[0371] Step IIA: A step in which an adhesive layer (X1) containing the polymer and the thermally expandable particles is formed by irradiating the above-mentioned polymeric composition layer with energy rays to form a polymer of the above-mentioned energy ray polymeric component;

[0372] Process IIIA: The process of forming an adhesive layer (X2) on the other side of the substrate (Y).

[0373] The following is an explanation of processes IA to IIIA.

[0374] [Process IA]

[0375] There are no particular limitations on process IA as long as it is a process of forming a polymeric composition layer on one side of the substrate (Y), but it is preferred to include the following processes IA-1 to IA-3.

[0376] Process IA-1: A process of forming a polymeric composition layer by coating a polymeric composition (x-1A) onto the peeling surface of the peeling material;

[0377] Step IA-2: A step of irradiating the above polymeric composition layer with a first energy ray to prepolymerize the energy ray polymeric components in the polymeric composition layer;

[0378] Process IA-3: The process of attaching a substrate (Y) to the polymeric composition layer after irradiation by the first energy ray.

[0379] (Process IA-1)

[0380] Process IA-1 is a process of forming a polymeric composition layer by coating a polymeric composition (x-1A) onto the peeling surface of the peeling material.

[0381] In process IA-1, methods for coating the polymeric composition (x-1A) onto the release material include, for example, spin coating, spray coating, wire rod coating, doctor blade coating, roller coating, scraper coating, mold coating, gravure coating, etc.

[0382] As described above, the polymerizable composition (x-1A) is preferably a solvent-free polymerizable composition. When the polymerizable composition (x-1A) is a solvent-free polymerizable composition, the solvent heating and drying step may not be performed in this process. On the other hand, if the polymerizable composition (x-1A) contains a solvent within a range that does not depart from the purpose of this invention, heating and drying may be performed after coating the polymerizable composition (x-1A), but the heating temperature in this case should be set below the expansion initiation temperature (t) of the thermally expandable particles.

[0383] (Process IA-2)

[0384] Process IA-2 is a process in which the polymeric composition layer formed in process IA-1 is irradiated with a first energy ray to prepolymerize the energy ray polymeric components in the polymeric composition layer.

[0385] The purpose of implementing the first energy ray irradiation is to achieve a high viscosity in the polymeric composition by prepolymerizing the energy ray polymeric components, thereby improving the shape retention of the polymeric composition layer.

[0386] During the first energy ray irradiation, the polymerizable components of the energy ray are not fully polymerized, but only prepolymerized. This improves the adhesion between the polymerizable composition layer and the substrate (Y) in process IA-3.

[0387] As the energy ray used in the first energy ray irradiation in process IA-2, ultraviolet light, which is easy to operate, is preferred among the aforementioned energy rays.

[0388] The preferred ultraviolet irradiance during first-energy ray irradiation is 70–250 mW / cm². 2 More preferably, it is 100–200 mW / cm 2 A further preferred value is 130–170 mW / cm². 2 Furthermore, the intensity of ultraviolet light in the first energy ray irradiation is preferably 40–200 mJ / cm². 2 More preferably 60–150 mJ / cm 2 Further preferred values ​​are 80–120 mJ / cm². 2 .

[0389] The first energy beam irradiation can be performed once or in multiple stages. Alternatively, to suppress the temperature rise of the polymeric composition layer caused by polymerization heat, the polymeric composition layer can be cooled while being irradiated.

[0390] (Process IA-3)

[0391] Process IA-3 is the process of bonding the substrate (Y) to the polymeric composition layer after irradiation by the first energy ray.

[0392] There is no particular limitation on the method of attaching the substrate (Y) to the polymeric composition layer. For example, the method of laminating the substrate (Y) to expose the side of the polymeric composition layer.

[0393] Lamination can be performed while heating or without heating, but from the viewpoint of suppressing the expansion of thermally expanding particles, it is preferable to perform it without heating. In this case, the polymeric composition layer that has been prepolymerized by irradiation with the first energy ray exhibits good adhesion to the substrate (Y) even without heating.

[0394] [Process IIA]

[0395] Process IIA is a process of forming a polymer of energy-ray polymerizable components by irradiating the polymeric composition layer formed in process IA with energy rays, and forming an adhesive layer (X1) containing the polymer and thermally expandable particles.

[0396] Here, when the first energy ray irradiation is performed in process IA, the energy ray irradiation in process IIA is the second energy ray irradiation performed on the prepolymerized polymeric composition layer.

[0397] The energy irradiation in step IIA differs from the first energy irradiation, and is preferably carried out to the point that even if further energy irradiation is performed, there will be virtually no further polymerization of the energy irradiation polymeric components.

[0398] In process IIA, energy rays irradiate the components, causing the polymerization of the energy ray polymerizable components to proceed, thereby forming a polymer of the energy ray polymerizable components that constitute the adhesive layer (X1).

[0399] The energy rays used in the energy irradiation of process IIA are preferably ultraviolet rays, which are easy to operate.

[0400] The ultraviolet irradiation intensity during energy ray irradiation in process IIA is preferably 100–350 mW / cm². 2 More preferably, it is 150–300 mW / cm 2 A further preferred value is 180–250 mW / cm². 2 .

[0401] The preferred intensity of ultraviolet light during energy irradiation in process IIA is 500–4,000 mJ / cm². 2 More preferably, it is 1,000 to 3,000 mJ / cm². 2 A further preferred value is 1,500–2,500 mJ / cm³. 2 .

[0402] The energy beam irradiation in process IIA can be performed once or in multiple stages. Alternatively, to suppress the temperature rise of the polymeric composition layer caused by polymerization heat, the polymeric composition layer can be cooled while being irradiated.

[0403] It should be noted that when process IA includes processes IA-1 to IA-3 as described above, the polymeric composition layer is obtained as an intermediate layer of a laminate formed by sequentially stacking a release material, the polymeric composition layer, and a substrate (Y). In this case, irradiation with a second energy ray can also be performed on the laminate having this configuration. From the viewpoint of being able to sufficiently irradiate the polymeric composition layer, which exists as an intermediate layer of the laminate, it is preferable to select one or more of the release material and the substrate (Y) that have energy ray transmittance.

[0404] From the viewpoint of suppressing the expansion of thermally expandable particles, it is preferable that none of the steps included in the above-mentioned steps IA and IIA include a step of heating the polymeric composition.

[0405] It should be noted that "heating" here refers to intentional heating, such as during drying or lamination, and does not include temperature rise caused by heat imparted to the polymerizable composition by energy ray irradiation, or by the heat of polymerization generated by the polymerization of the energy ray polymerizable composition.

[0406] When a heating process of the polymerizable composition is included as needed, the heating temperature is preferably "a temperature below the expansion initiation temperature (t)," more preferably "expansion initiation temperature (t) - 5°C" or less, further preferably "expansion initiation temperature (t) - 10°C" or less, and even more preferably "expansion initiation temperature (t) - 15°C" or less. Furthermore, if the temperature of the polymerizable composition unexpectedly rises, cooling is preferable to bring the temperature of the polymerizable composition back to the aforementioned temperature range.

[0407] [Process IIIA]

[0408] Process IIIA is the process of forming an adhesive layer (X2) on the other side of the substrate (Y).

[0409] The adhesive layer (X2) preferably includes the following processes IIIA-1 and IIIA-2.

[0410] Process IIIA-1: A process of applying an adhesive composition (x-2) to one side of the peelable material to form an adhesive layer (X2);

[0411] Process IIIA-2: The process of attaching the adhesive layer (X2) formed in process IIIA-1 to the other side of the substrate (Y).

[0412] In step IIIA-1, the method for coating the adhesive composition (x-2) can be the same as the method for coating the polymerizable composition (x-1A) in step IA-1. Additionally, if the adhesive layer (X2) contains a solvent, a step of drying the coating film after coating the adhesive composition (x-2) may also be included.

[0413] It should be noted that, as described above, from the viewpoint of suppressing the phenomenon of the adhesive layer and the two release materials being cut off and detached together, it is preferable to design the release material used in step IIIA-1 and the release material used in step IA-1 to have different release forces.

[0414] In step IIIA-2, as a method for bonding the adhesive layer (X2) to the substrate (Y), the same method as the method for bonding the substrate (Y) to the polymeric composition layer in step IA-3 can be listed, and the preferred embodiment is also the same.

[0415] -Method using adhesive composition (x-1B)-

[0416] When the adhesive composition (x-1B) described above is used in the formation of the adhesive layer (X1), the adhesive sheet used in one aspect of the present invention can be manufactured by, for example, a method including the steps IB to IIIB described below.

[0417] • Process IB: A process in which an adhesive composition (x-1B) is applied to the peeling surface of the peeling material to form a coating film, and the coating film is dried to form an adhesive layer (X1).

[0418] • Process IIB: A process in which an adhesive composition (x-2) is applied as a forming material for an adhesive layer to the peeling surface of another peeling material to form a coating film, and the coating film is dried to form an adhesive layer (X2).

[0419] • Process IIIB: A process in which the adhesive layer (X1) formed in process IB is bonded to one side of the substrate, and the adhesive layer (X2) formed in process IIB is bonded to the other side of the substrate.

[0420] The preferred methods and conditions for coating, drying and bonding the adhesive composition in each process are the same as those described in the method of using the polymeric composition (x-1A) above.

[0421] [Each step in the manufacturing process of a semiconductor device]

[0422] Hereinafter, the steps included in the method for manufacturing a semiconductor device, which is one aspect of the present invention, will be described sequentially with reference to the accompanying drawings. It should be noted that the following description will primarily focus on the case where a semiconductor wafer is used as the workpiece, but the same applies to other workpieces.

[0423] <Process 1>

[0424] Step 1 is the process of attaching the object to be processed to the adhesive layer (X2) of the adhesive sheet and attaching the support to the adhesive layer (X1).

[0425] Figure 2 The diagram shows a cross-sectional view illustrating the process of attaching a semiconductor wafer W to an adhesive layer (X2) on an adhesive sheet 1a and attaching a support 2 to an adhesive layer (X1).

[0426] The bonding of the semiconductor wafer W makes the surface W1, which serves as the circuit surface, become the adhesive layer (X2) side.

[0427] The semiconductor wafer W can be a silicon wafer, or a wafer made of gallium arsenide, silicon carbide, sapphire, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, or glass.

[0428] The thickness of a semiconductor wafer W before grinding is typically 500–1,000 μm.

[0429] The circuitry on the surface W1 of a semiconductor wafer W can be formed using conventional methods such as etching or lift-off.

[0430] The material of the support 2 can be appropriately selected based on the type of object being processed, the processing content, and other factors, taking into account the required characteristics such as mechanical strength and heat resistance.

[0431] Examples of materials that can be used as the support 2 include: metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; resin materials such as epoxy resin, ABS resin, acrylic resin, engineering plastics, special engineering plastics, polyimide resin, and polyamide-imide resin; and composite materials such as glass and epoxy resin. Among these materials, SUS, glass, and silicon wafers are preferred.

[0432] Examples of engineering plastics mentioned above include nylon, polycarbonate (PC), and polyethylene terephthalate (PET).

[0433] Examples of the aforementioned special engineering plastics include polyphenylene sulfide (PPS), polyethersulfone (PES), and polyether ether ketone (PEEK).

[0434] The support 2 is preferably adhered to the entire adhesive surface of the adhesive layer (X1). Therefore, the area of ​​the surface of the support 3 adhered to the adhesive surface of the adhesive layer (X1) is preferably greater than the area of ​​the adhesive surface of the adhesive layer (X1). In addition, the surface of the support 3 adhered to the adhesive surface of the adhesive layer (X1) is preferably planar.

[0435] The shape of the support 2 is not particularly limited, but it is preferably plate-shaped.

[0436] The thickness of the support 2 can be appropriately selected considering the required characteristics, preferably 20μm or more and 50mm or less, more preferably 60μm or more and 20mm or less.

[0437] <Process 2>

[0438] Step 2 is a process of performing one or more treatments on the above-mentioned workpiece, selected from grinding and single-piece processing.

[0439] Examples of processing methods selected from grinding and single-piece processing include: grinding using a grinding machine; and single-piece processing based on blade cutting, laser cutting, Stealth Dicing (registered trademark), blade tip cutting, and stealth tip cutting.

[0440] Among these, the preferred methods are single-piece processing based on Stealth Dicing, grinding and single-piece processing based on blade tip cutting, and grinding and single-piece processing based on stealth tip cutting. More preferred methods are grinding and single-piece processing based on blade tip cutting and grinding and single-piece processing based on stealth tip cutting.

[0441] Stealth dicing is a method of monolithizing a semiconductor wafer by irradiating it with a laser to create a modified region inside the wafer and using this modified region as the starting point for dicing. The modified region formed in the semiconductor wafer is a portion that has become brittle due to multiphoton absorption. During wafer expansion, stress is applied to the semiconductor wafer in a direction parallel to the wafer surface and in which the wafer expands. This causes the wafer to extend from the modified region towards the surface and back surface cracks of the semiconductor wafer, thereby monolithizing it into a semiconductor chip. In other words, the modified region is formed along the dicing line used during monolithization.

[0442] The modified region is formed inside the semiconductor wafer by irradiating it with a laser whose focal point is focused on the interior of the semiconductor wafer. The incident surface of the laser can be either the surface or the back surface of the semiconductor wafer. Alternatively, the incident surface of the laser can be the surface with an adhesive sheet attached, in which case the laser is irradiated onto the semiconductor wafer via the adhesive sheet.

[0443] The blade tip cutting method, also known as DBG (Dicing Before Grinding), involves pre-forming grooves along predetermined lines on a semiconductor wafer to a depth shallower than its thickness. The wafer is then subjected to back-side grinding, extending at least to the grooves, to achieve thinning and monolithic wafer formation. The grooves reached by the grinding surface become cuts through the semiconductor wafer, which are then divided into monolithic semiconductor chips. The pre-formed grooves are typically located on the surface (circuit plane) of the semiconductor wafer and can be formed by cutting, for example, using a conventional wafer dicing apparatus equipped with a dicing blade.

[0444] Stealth Dicing Before Grinding (SDBG) is a method similar to Stealth Dicing, where a modified region is created inside a semiconductor wafer by irradiating it with a laser, and the wafer is then monolithically assembled from this modified region. However, SDBG differs from Stealth Dicing in that it simultaneously thins the wafer through grinding and assembling it into a semiconductor chip. Specifically, the semiconductor wafer with the modified region is thinned by back-side grinding, and pressure is applied to the wafer at this time to propagate cracks from the modified region toward the bonding surface of the adhesive layer, thereby monolithically assembling the wafer into a semiconductor chip.

[0445] It should be noted that the grinding thickness after the modified region is formed can be the thickness that reaches the modified region. However, even if it does not reach the modified region precisely, it can be ground to a position near the modified region and then cut off by the processing pressure of a grinding stone or the like.

[0446] In the SDBG process, after the semiconductor chips are monolithically formed, they are in a state of mutual contact, which easily leads to a phenomenon known as chipping, where small defects are generated at the outer edges due to vibration. Therefore, the semiconductor device manufacturing method of one aspect of the present invention, which can suppress vibration by firmly fixing it relative to a support, is particularly suitable for the SDBG process.

[0447] When using a blade tip cutting method to monolithize a semiconductor wafer W, it is preferable to pre-form a groove on the surface W1 of the semiconductor wafer W to be bonded to the adhesive layer (X2) in step 1.

[0448] On the other hand, when using the stealth tip cutting method to monolithize the semiconductor wafer W, the modified area can be pre-formed by irradiating the semiconductor wafer W to be pasted onto the adhesive layer (X2) in step 1 with a laser, or the modified area can be formed by irradiating the semiconductor wafer W already pasted onto the adhesive layer (X2) with a laser.

[0449] Figure 3 A cross-sectional view is shown illustrating the process of forming multiple modified regions 4 relative to a semiconductor wafer W bonded to an adhesive layer (X2) using a laser irradiation device 3.

[0450] A laser is irradiated from the back side W2 of the semiconductor wafer W, thereby forming multiple modified regions 4 at substantially equal intervals inside the semiconductor wafer W.

[0451] Figure 4A cross-sectional view is shown illustrating the process of grinding the back side W2 of a semiconductor wafer W with modified regions 4 using a grinding machine 5, and thinning the semiconductor wafer W into multiple semiconductor chips CP by cutting along the edge starting from the modified regions 4.

[0452] For a semiconductor wafer W with modified region 4 formed, for example, its back surface W2 is ground while the support 3 supporting the semiconductor wafer W is fixed on a fixed table such as a chuck table.

[0453] The thickness of the ground semiconductor chip CP is preferably 5 to 100 μm, more preferably 10 to 45 μm. In addition, when grinding and monolithic processing are performed by stealth tip cutting, it becomes easier to obtain a semiconductor chip CP with a thickness of 50 μm or less, more preferably 10 to 45 μm.

[0454] The size of the ground semiconductor chip CP, viewed from above, is preferably less than 600 mm. 2 More preferably, less than 400mm 2 Further optimization is preferred for thicknesses below 300mm. 2 It should be noted that the "top view" refers to viewing along the thickness direction.

[0455] The shape of a monolithic semiconductor chip (CP) when viewed from above can be square, rectangular, or other elongated shapes.

[0456] <Process 3>

[0457] Step 3 is the process of attaching a thermosetting film to the side of the workpiece opposite to the adhesive layer (X2) after the above processing has been performed.

[0458] Figure 5 A cross-sectional view is shown illustrating the process of attaching a thermosetting film 6 with a support sheet 7 to the side opposite to the adhesive layer (X2) of a plurality of semiconductor chips CP obtained by performing the above-described process.

[0459] Thermosetting film 6 is a thermosetting film obtained by forming a resin composition containing at least a thermosetting resin, and is used as an adhesive when mounting a semiconductor chip CP onto a substrate. Thermosetting film 6 may also contain, as needed, a curing agent of the aforementioned thermosetting resin, a thermoplastic resin, an inorganic filler, a curing accelerator, etc.

[0460] As the thermosetting film 6, a thermosetting film commonly used as, for example, a chip bonding film, a chip mounting film, etc. can be used.

[0461] The thickness of the thermosetting film 6 is not particularly limited, but it is usually 1 to 200 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm.

[0462] The support sheet 7 can be made of any material that can support the thermosetting film 6. Examples of materials include resin, metal, and paper, which are used as the substrate (Y) of the adhesive sheet in one aspect of the present invention.

[0463] As a method for attaching the thermosetting film 6 to multiple semiconductor chips CP, examples include lamination-based methods.

[0464] Lamination can be performed while heating or without heating. When lamination is performed while heating, from the viewpoint of suppressing the expansion of thermally expandable particles and suppressing thermal changes in the adhered material, the heating temperature is preferably "a temperature below the expansion initiation temperature (t)", more preferably "expansion initiation temperature (t) - 5°C" or less, further preferably "expansion initiation temperature (t) - 10°C" or less, and even more preferably "expansion initiation temperature (t) - 15°C" or less.

[0465] <Process 4>

[0466] Step 4 is a step of separating the adhesive layer (X1) and the support body by heating the adhesive sheet to above the expansion initiation temperature (t).

[0467] Figure 6 A cross-sectional view is shown illustrating the process of separating the adhesive layer (X1) from the support 2 by heating the adhesive sheet 1a.

[0468] The heating temperature in step 4 is at or above the expansion initiation temperature (t) of the thermally expandable particles, preferably "above the expansion initiation temperature (t)," more preferably "expansion initiation temperature (t) + 2°C" or more, further preferably "expansion initiation temperature (t) + 4°C" or more, and even more preferably "expansion initiation temperature (t) + 5°C" or more. Furthermore, from the viewpoint of energy efficiency and suppressing thermal changes in the adhered material during heat peeling, the heating temperature in step 4 is preferably "expansion initiation temperature (t) + 50°C" or less, more preferably "expansion initiation temperature (t) + 40°C" or less, and even more preferably "expansion initiation temperature (t) + 20°C" or less.

[0469] From the viewpoint of suppressing thermal changes in the adhered material, the heating temperature in step 4 is in the range above the expansion initiation temperature (t), preferably below 120°C, more preferably below 115°C, further preferably below 110°C, and even more preferably below 105°C.

[0470] <Process 5>

[0471] Step 5 is a step of separating the adhesive layer (X2) from the object being processed by irradiating the adhesive layer (X2) with energy rays.

[0472] Figure 7 A cross-sectional view illustrating the process of separating the adhesive layer (X2) and multiple semiconductor chips CP is shown.

[0473] Since the adhesive layer (X2) will cure by irradiation with energy rays, resulting in a decrease in adhesive strength, the workpiece can be easily separated from the adhesive layer (X2) by irradiation with energy rays.

[0474] As for the energy rays used in the energy irradiation of step 5, ultraviolet light, which is easy to operate, is preferred among the aforementioned energy rays. Regarding the illuminance and intensity of the ultraviolet light, any illuminance and intensity sufficient to sufficiently reduce the adhesion between the adhesive layer (X2) and the workpiece is acceptable; for example, the illuminance of the ultraviolet light is preferably 100–400 mW / cm². 2 More preferably, it is 150–350 mW / cm 2 A further preferred value is 180–300 mW / cm². 2 The preferred intensity of ultraviolet light is 100–2,000 mJ / cm². 2 More preferably, 200–1,000 mJ / cm² 2 A further preferred value is 300–500 mJ / cm². 2 .

[0475] The energy rays can be applied from any direction as long as they can cure the adhesive layer (X2), but from the viewpoint of ensuring effective curing, it is preferable to apply the energy rays from the adhesive layer (X1) side. In this case, from the viewpoint of being able to sufficiently irradiate the adhesive layer (X2) with energy rays, the substrate (Y) and the adhesive layer (X1) preferably have energy ray transmittance.

[0476] After the above processes 1 to 5, multiple semiconductor chips CP can be obtained by pasting them onto the thermosetting film 6.

[0477] Next, preferably, the thermosetting film 6 on which multiple semiconductor chips CP are attached is divided into shapes identical to the semiconductor chips CP to obtain a semiconductor chip CP with thermosetting film 6. Methods for dividing the thermosetting film 6 can include, for example, laser cutting, wafer enlargement, or melting using a laser.

[0478] Figure 8 The semiconductor chip CP is shown as having a thermosetting film 6 divided into the same shape as the semiconductor chip CP.

[0479] For the semiconductor chip CP with thermosetting film 6, after further performing a wafer expansion process to increase the spacing between the semiconductor chip CPs as needed, a rearrangement process to arrange the multiple semiconductor chip CPs with increased spacing, and a flipping process to flip the front and back sides of the multiple semiconductor chip CPs, the chip is attached (chip mounting) to the substrate from the thermosetting film 6 side. Then, by thermally curing the thermosetting film 6, the semiconductor chip and the substrate can be bonded together.

[0480] Example

[0481] The present invention will be specifically described in conjunction with the following embodiments, but the present invention is not limited to the following embodiments.

[0482] It should be noted that in the following description, "non-expanding adhesive layer (X1')" means an adhesive layer that does not contain thermally expanding particles. The adhesive layer that does not contain thermally expanding particles and is used to determine the shear storage modulus G' is a non-expanding adhesive layer (X1').

[0483] The physical property values ​​in the following examples are values ​​determined by the following methods.

[0484] [Weight-average molecular weight (Mw)]

[0485] The values ​​were determined using a gel permeation chromatography apparatus (manufactured by Tosoh Corporation, product name "HLC-8020") under the following conditions and converted to standard polystyrene.

[0486] (Measurement conditions)

[0487] • Chromatographic column: A chromatographic column consisting of “TSK guard column HXL-L”, “TSK gel G2500HXL”, “TSK gel G2000HXL”, and “TSK gel G1000HXL” (all manufactured by Tosoh Corporation) connected in sequence.

[0488] Column temperature: 40℃

[0489] • Developing solvent: Tetrahydrofuran

[0490] • Flow rate 1.0 mL / min

[0491] [Thickness of each layer]

[0492] The measurement was performed using a constant pressure thickness gauge (model: "PG-02J", standard: based on JIS K6783, Z1702, Z1709) manufactured by TECLOCK Co., Ltd.

[0493] Average particle size (D) of thermally expandable particles 50 ), 90% particle size (D90 )]

[0494] The particle distribution of thermally expandable particles before expansion at 23°C was determined using a laser diffraction particle size distribution measuring device (e.g., Malvern, product name "Mastersizer 3000").

[0495] Furthermore, the cumulative volume frequency of the smallest particles in the particle distribution, corresponding to 50% and 90% of the particle size, is taken as the "average particle size (D) of thermally expandable particles". 50 ")" and "90% particle size of thermally expandable particles (D 90 )".

[0496] [Storage modulus E' of substrate (Y)]

[0497] The substrate (Y) cut into 5mm x 30mm sections was used as the test sample. The storage modulus E' at a given temperature was measured using a dynamic viscoelasticity measuring device (manufactured by TAINSTRUMENTS, product name "DMAQ800") under the following conditions: test start temperature 0℃, test end temperature 200℃, heating rate 3℃ / min, frequency 1Hz, and amplitude 20μm.

[0498] [Shear storage modulus G'(23) of adhesive layer (X1) at 23°C]

[0499] The adhesive layer (X1) was made into a diameter of 8 mm × thickness of 3 mm and used as a test sample. The shear storage modulus G' (23) at 23 °C was determined by torsional shear method under the conditions of test start temperature of 0 °C, test end temperature of 300 °C, heating rate of 3 °C / min and frequency of 1 Hz.

[0500] [Shear storage modulus G' of the non-expanding adhesive layer (X1')]

[0501] In order to determine the shear storage modulus G' after excluding the influence of thermally expanding particles, a non-expanding adhesive layer (X1') with the same structure as the adhesive layer (X1) except that it does not contain thermally expanding particles in each manufacturing example was prepared as a sample for measuring the shear storage modulus corresponding to the adhesive layer (X1) of each manufacturing example, and its shear storage modulus G' was measured.

[0502] A non-expanding adhesive layer (X1') was made into a sample with a diameter of 8 mm and a thickness of 3 mm. The shear storage modulus G'(23) at 23 °C and the shear storage modulus G'(t) at the expansion initiation temperature (t) of the thermally expandable particles were determined by torsion shear method under the conditions of test initiation temperature of 0 °C, test termination temperature of 300 °C, heating rate of 3 °C / min and frequency of 1 Hz.

[0503] It should be noted that the expansion initiation temperature (t) of the thermally expandable particles in the non-expandable adhesive layer (X1') of the sample used for shear storage modulus determination refers to the expansion initiation temperature (t) of the thermally expandable particles contained in the adhesive layer (X1) of the manufacturing example corresponding to the sample used for shear storage modulus determination. In this manufacturing example, as will be described later, it refers to 88°C.

[0504] Synthesis example 1

[0505] (Synthesis of carbamate acrylate prepolymers)

[0506] 100 parts by weight of polypropylene glycol (weight-average molecular weight (Mw) 3,000, 4 parts by weight of hexamethylene diisocyanate, and 0.02 parts by weight of dioctyltin dilaurate were mixed and stirred at 80°C for 6 hours to obtain the reactant. Infrared spectroscopy was used to determine the IR spectrum of the obtained reactant, confirming that the isocyanate groups had essentially disappeared.

[0507] Then, 1 part by mass of 2-isocyanoethyl acrylate was mixed relative to the total amount of the obtained reactants, and the mixture was stirred at 80°C for 3 hours to obtain a urethane acrylate prepolymer. Infrared spectroscopy was used to determine the IR spectrum of the obtained urethane acrylate prepolymer, confirming that the isocyanate groups had essentially disappeared. The weight-average molecular weight (Mw) of the obtained urethane acrylate prepolymer was 25,000.

[0508] [Manufacturing of adhesive sheets]

[0509] Manufacturing Examples 1-3

[0510] (Preparation of polymeric compositions)

[0511] By mixing the components listed in Table 1 according to the formulation, a solvent-free polymerizable composition was obtained. It should be noted that the details of each component listed in Table 1 are as follows.

[0512] [Polymerizable vinyl monomers]

[0513] 2EHA: 2-Ethylhexyl acrylate ((a1-1) component)

[0514] IBXA: Isoborneol Acrylate ((a1-2) component)

[0515] HEA: 2-Hydroxyethyl acrylate ((a1-3) component)

[0516] 4HBA: 4-Hydroxybutyl acrylate ((a1-3) component)

[0517] [Multifunctional (meth)acrylate monomers]

[0518] Trifunctional monomer: Ethylene oxide-modified triacrylate isocyanurate ((a1-4) component)

[0519] [Multifunctional (meth)acrylate prepolymer]

[0520] Carbamate acrylate prepolymer: Component ((a2) component) prepared in Synthesis Example 1

[0521] Polyacrylamide acrylate prepolymer: "KANEKA XMAP (registered trademark) RC100C" (manufactured by Kaneka Corporation, polyacrylic acid prepolymer with acrylamide groups at both ends, weight average molecular weight (Mw): 21,500) ((a2) composition)

[0522] [Photopolymerization initiator]

[0523] 1-Hydroxycyclohexylphenyl ketone

[0524] [Particles with thermal expansion]

[0525] Manufactured by AkzoNobel, product name "Expancel (registered trademark) 031-40" (DU type), expansion initiation temperature (t) = 88℃, average particle size (D) 50 =12.6μm, 90% particle size (D) 90 = 26.2μm

[0526] It should be noted that in Table 1, “-” in “Composition of Adhesive Layer (X1) or Non-expanding Adhesive Layer (X1')” indicates that the component is not included.

[0527] (Making the adhesive sheet)

[0528] An adhesive sheet was manufactured using the solvent-free polymeric composition described above, in the following order.

[0529] A solvent-free polymerizable composition was coated onto the release surface of a polyethylene terephthalate (PET) release film (manufactured by Lintec Corporation, product name "SP-PET382150", thickness: 38 μm) to form a polymerizable composition layer. This polymerizable composition layer was then subjected to an illuminance of 150 mW / cm². 2 Light intensity 100mJ / cm 2 Prepolymerization was performed by irradiating the material with ultraviolet light. The thickness of the polymeric composition layer was adjusted in such a way that the thickness of the resulting adhesive layer (X1) was as described in Table 2.

[0530] Next, a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., Cosmo Shine (registered trademark), product number "A4300", thickness: 50 μm) serving as the substrate (Y) was adhered to the exposed side of the aforementioned polymeric composition layer, thus obtaining a laminate consisting of a release film, a polymeric composition layer, and the substrate (Y) stacked sequentially. It should be noted that the storage modulus E'(23) of the substrate (Y) at 23°C is 3.0 × 10⁻⁶. 9 The storage modulus E'(t) of Pa and substrate (Y) at the expansion initiation temperature (t) of the thermally expanding particles is 2.4 × 10⁻⁶. 9 Pa.

[0531] The laminate obtained above is subjected to an illuminance of 200 mW / cm² from the peel film side. 2 Light intensity 2,000 mJ / cm 2 (at 500mJ / cm) 2 The adhesive layer (X1) was formed by irradiating ultraviolet light under the condition of irradiation 4 times, resulting in an adhesive sheet in which a release film, an adhesive layer (X1) and a substrate (Y) were sequentially stacked.

[0532] It should be noted that the illuminance and light intensity mentioned above during ultraviolet irradiation were measured using an illuminance / light intensity meter (manufactured by EIT Corporation, product name "UV Power Puck II").

[0533] Next, the adhesive sheets produced in each example were evaluated as follows. The evaluation results are shown in Table 2.

[0534] [Determination of adhesive strength of adhesive layer (X1) at 23°C before thermal expansion]

[0535] The release film was removed from the adhesive layer (X1) of the adhesive sheet cut into 25mm×250mm pieces. Based on JIS Z0237:2000, the surface of the exposed adhesive layer (X1) was bonded to the mirror surface of the silicon mirror wafer using a 2kg rubber roller. The wafer was then immediately left to stand for 20 minutes at 23°C and 50% RH (relative humidity).

[0536] After standing under the above conditions, the adhesive force was measured in an environment of 23°C and 50% RH (relative humidity) using a tensile testing machine (manufactured by A&D Corporation, product name "TENSILON (registered trademark)"), based on JIS Z0237:2000, using the 180° peel method, at a tensile speed of 300 mm / min.

[0537] [Determination of adhesive strength of adhesive layer (X1) at 23°C after thermal expansion]

[0538] In addition, the above-mentioned test sample was placed on a hot plate with the silicon mirror wafer in contact with the hot plate and the adhesive side out of contact with the hot plate. It was heated at 100°C above the expansion initiation temperature of the thermally expanding particles for 1 minute and then left to stand in a standard environment (23°C, 50% RH (relative humidity)) for 60 minutes. Based on JIS Z0237:2000, the adhesive force of the adhesive layer (X1) was measured using the 180° peel method at a tensile speed of 300 mm / min.

[0539] It should be noted that if the adhesive force is too small when fixing the adhesive sheet for testing, resulting in unexpected peeling and making it difficult to measure the adhesive force, the adhesive force is considered to be 0 N / 25 mm.

[0540] [Evaluation of self-peeling properties]

[0541] The release film was removed from the adhesive layer (X1) of the adhesive sheet cut into 50mm × 50mm pieces. Based on JIS Z0237:2000, the exposed surface of the adhesive layer (X1) was bonded to the mirror surface of the silicon mirror wafer using a 2kg rubber roller. Immediately afterward, it was left to stand for 20 minutes at 23°C and 50% RH (relative humidity) as a test sample. Next, the test sample was placed on a hot plate with the silicon mirror wafer in contact with the hot plate and the adhesive sheet side out of contact. It was heated for a maximum of 60 seconds at 100°C, above the expansion initiation temperature of the thermally expanding particles. The percentage (%) of the peeled area of ​​the adhesive sheet at the time of 60 seconds of heating was calculated (peeled area × 100 / total area of ​​the adhesive sheet), and evaluated according to the following criteria.

[0542] A: The adhesive sheet peeled off completely within 60 seconds.

[0543] B: The area that peeled off after heating for 60 seconds was more than 30% but less than 100%.

[0544] C: The area that peeled off after heating for 60 seconds was less than 30%.

[0545] In addition, for samples rated "A", the time (in seconds) required until the entire surface was peeled off was measured.

[0546] [Table 1]

[0547]

[0548] [Table 2]

[0549]

[0550] As shown in Table 2, the adhesive sheets manufactured in Examples 1 to 3 all have sufficient adhesive strength before heat peeling, but can be heat peeled at a low temperature (100°C). Furthermore, it can be seen that the adhesive strength and self-peeling properties of these adhesive sheets can be adjusted by modifying the composition of the polymeric composition and the thickness of the adhesive layer (X1).

[0551] [Semiconductor device manufacturing]

[0552] Example 1

[0553] Next, a semiconductor device was manufactured using the manufacturing method of this embodiment.

[0554] It should be noted that the double-sided adhesive sheet used in the manufacturing method of semiconductor devices is made by the method shown below.

[0555] [Making Double-Sided Adhesive Sheets]

[0556] (1) Preparation of energy-ray curable adhesive composition (x-2)

[0557] 52 parts by mass of butyl acrylate, 20 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate were solution polymerized in ethyl acetate to obtain a non-energy-curable acrylic copolymer. A amount of methacryloyloxyethyl isocyanate, with an isocyanate group number equivalent to 0.9 equivalents of the total number of hydroxyl groups in the resulting acrylic copolymer, was added to the solution containing the acrylic copolymer and reacted to generate an energy-curable acrylic copolymer (1) (Mw: 1 million) with energy-polymerizable side chains.

[0558] Then, relative to 100 parts by weight of the solid content of the acrylic copolymer (1), 0.5 parts by weight of isocyanate crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate L") as a crosslinking agent (solid content ratio) and 0.57 parts by weight of 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins Corporation, product name "Omnirad 184") as a photopolymerization initiator (solid content ratio) were added to prepare a solution of energy-ray curable adhesive composition (x-2).

[0559] (2) Manufacturing of double-sided adhesive sheets

[0560] An adhesive sheet (1) was prepared by sequentially stacking a release film, an adhesive layer (X1), and a substrate (Y) as manufactured in Example 1.

[0561] On the other hand, the energy-curable adhesive composition (x-2) prepared above was coated on the release treatment surface of a polyethylene terephthalate (PET) release film (manufactured by Lintec Corporation, product name "SP-PET381031", thickness: 38 μm), and dried at 100°C for 1 minute to form an adhesive layer (X2) (thickness: 20 μm) on the release film.

[0562] Then, the adhesive layer (X2) is bonded to the substrate (Y) of the adhesive sheet (1) to obtain a double-sided adhesive sheet formed by sequentially stacking the release film, adhesive layer (X1), substrate (Y), adhesive layer (X2) and release film.

[0563] [Semiconductor device manufacturing]

[0564] (Process 1)

[0565] Using a back-grinding tape laminator (manufactured by Lintec Corporation, device name "RAD-3510F / 12"), on a table at room temperature (25°C), the material after removing the release film from the adhesive layer (X2) of the double-sided adhesive sheet prepared above is laminated onto the circuit surface of a 12-inch diameter, 730μm thick wafer with patterned circuit surfaces in such a way that the adhesive layer (X2) is brought into contact with the circuit surface of the wafer.

[0566] On the other hand, a mirror wafer (12 inches in diameter and 750 μm thick) was attached to the adhesive layer (X1) exposed after the release film was removed from the adhesive layer (X1) of the double-sided adhesive sheet, thus obtaining a laminate consisting of the support, the double-sided adhesive sheet and the wafer stacked in sequence.

[0567] (Process 2)

[0568] Next, a stealth laser irradiation device (DISCO Corporation, device name "DFL7361") was used to irradiate the back side of the wafer opposite to the circuit formation surface, creating a modified region inside the wafer. Then, a grinding / polishing machine (DISCO Corporation, device name "DGP8761") was used to grind the back side of the wafer while exposing it to ultrapure water, resulting in a chip with a thickness of 20 μm. It should be noted that during these processes, vibrations and misalignments of the workpiece caused by insufficient adhesion between the double-sided adhesive sheet and the support were effectively suppressed.

[0569] (Process 3)

[0570] Next, a chip mounting film with a support sheet is attached to the back side of the monolithized chip using a pick-and-place machine (manufactured by Lintec Corporation, product name "RAD2700") at 50°C, so that the back side of the chip is in contact with the chip mounting film, thus obtaining a laminate having a support, an adhesive sheet, a chip, a chip mounting film and a support sheet in sequence.

[0571] (Step 4)

[0572] The aforementioned laminate was placed on the hot plate with the support side in contact with the hot plate, and heated at 100°C for 1 minute above the expansion initiation temperature of the thermally expandable particles to separate the adhesive layer (X1) of the adhesive sheet from the support.

[0573] It should be noted that, in terms of the adhesion between the heated adhesive layer (X1) and the support, when the support is facing upwards and the adhesive sheet with the chip is facing downwards, the adhesive sheet with the chip is reduced to the point where it will fall off due to its weight.

[0574] (Step 5)

[0575] Next, the adhesive layer (X1) of the adhesive sheet exposed after separation from the support was illuminated at an illuminance of 230 mW / cm². 2 Light intensity 380mJ / cm 2 Under conditions of ultraviolet irradiation, the adhesive layer (X2) was cured, causing a decrease in adhesion, and then the adhesive layer (X2) was separated from the chip. The surface of the chip after separation from the adhesive layer (X2) was visually inspected, and no contamination or residual adhesive was detected.

[0576] After the chip mounting film is cut into shapes identical to the chip, the support sheet is removed, resulting in a monolithically formed chip with the chip mounting film. A chip bonding machine is then used to attach the chip with the chip mounting film to a substrate from the chip mounting film side, and the chip mounting film is thermally cured, thereby bonding the chip to the substrate and obtaining a semiconductor device.

[0577] As can be seen from the above, the semiconductor device manufacturing method of one aspect of the present invention has excellent processability and productivity of the workpiece, and will not contaminate the workpiece due to thermally expandable particles and expanded adhesive layer.

Claims

1. A method for manufacturing a semiconductor device, comprising a method for manufacturing a semiconductor device using an adhesive sheet, the adhesive sheet comprising, in sequence, an adhesive layer X1 containing thermally expanding particles, a substrate Y, and an adhesive layer X2 that is cured by irradiation with energy rays, thereby resulting in reduced adhesive strength. The expansion initiation temperature (t) of the thermally expandable particles is 50~100℃. This method includes the following steps 1 to 5: Step 1: The step of attaching the object to be processed to the adhesive layer X2 of the adhesive sheet and attaching the support to the adhesive layer X1 of the adhesive sheet; Step 2: Performing one or more processing treatments on the workpiece selected from grinding and single-piece processing; Step 3: A step of attaching a thermosetting film to the side of the workpiece opposite to the adhesive layer X2 after the aforementioned processing. Step 4: The process of separating the adhesive layer X1 from the support by heating the adhesive sheet to above the expansion initiation temperature (t) of the thermally expandable particles and below 110°C; Step 5: A step of separating the adhesive layer X2 from the workpiece by irradiating it with energy rays. After step 5 above, the workpiece and the substrate are bonded together by heat curing the thermosetting film on the workpiece to the thermosetting film.

2. The method for manufacturing a semiconductor device according to claim 1, wherein, The processing methods are: single-piece processing based on stealth cutting, grinding processing and single-piece processing based on blade tip cutting, or grinding processing and single-piece processing based on stealth tip cutting.

3. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The content of the thermally expandable particles is 1 to 30% by mass relative to the total mass (100% by mass) of the adhesive layer X1.

4. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The average particle size D of the thermally expandable particles at 23°C 50 The range is 1~30μm.

5. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The storage modulus E' of substrate Y at 23℃ is 5.0 × 10⁻⁶. 7 ~5.0×10 9 Pa.

6. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The object being processed is a semiconductor wafer.

7. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The energy rays mentioned are ultraviolet rays.

8. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, In step 4, the adhesive sheet is heated from the support side.

9. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, In step 4, the support side of the adhesive sheet is heated using a hot plate.

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