Method for manufacturing semiconductor device and semiconductor wafer with adhesive sheet for semiconductor processing

Abstract

The present application relates to a method for manufacturing a semiconductor device using a semiconductor processing adhesive sheet having a substrate, an intermediate layer, and an adhesive layer in this order, and one or more of the substrate, the intermediate layer, and the adhesive layer contains thermally expandable particles, the method comprising steps 1 to 4.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor device and a semiconductor wafer with a semiconductor processing adhesive sheet. Background Technology

[0002] With the rapid development of information terminal equipment towards thinner, smaller, and more multifunctional designs, the semiconductor devices mounted on these devices are also required to be thinner and denser.

[0003] In the manufacturing process of semiconductor devices, processes such as back-side grinding and monolithization of semiconductor wafers are performed. In order to protect the circuit surface of the semiconductor wafer, these processes are performed while the semiconductor processing adhesive sheet is attached to the circuit surface of the semiconductor wafer.

[0004] As an adhesive sheet for semiconductor processing, an adhesive sheet having an adhesive layer and a substrate supporting the adhesive layer is typically used. With the adhesive layer of the semiconductor processing adhesive sheet adhered to the circuit surface of a semiconductor wafer, and the substrate fixed to a support device such as a chuck stage, back-side grinding and monolithization of the semiconductor wafer are performed while protecting the circuit surface. Then, after the given processing has been completed, the semiconductor processing adhesive sheet is peeled off from the surface of the semiconductor wafer.

[0005] However, the surface of the semiconductor wafer to which the semiconductor processing adhesive is attached is not necessarily flat; sometimes the semiconductor processing adhesive is attached to a surface with protrusions. For example, in recent years, flip-chip bonding technology has been put into practical use as a technology for miniaturizing semiconductor device modules. This flip-chip bonding technology involves back-side grinding and monolithization of a semiconductor wafer (hereinafter also referred to as a "bumped wafer") with multiple bumps having a height of about tens to hundreds of μm formed on the circuit surface, and then directly bonding these bumps to the wiring substrate.

[0006] When a semiconductor processing adhesive sheet is bonded to the bump-forming surface of a bump-bumped wafer, the portion of the adhesive sheet covering the bump is raised higher than other portions, sometimes creating a protrusion on the substrate side opposite to the bonding surface. When the surface with this protrusion is fixed and the back side of the semiconductor wafer is ground, the uniformity of the thickness of the semiconductor wafer after back side grinding deteriorates.

[0007] To alleviate the above problems, sometimes an intermediate layer for embedding the protrusions is provided on the semiconductor processing adhesive sheet that is pasted onto the surface with the protrusions.

[0008] In Patent Document 1, a temporary fixing strip for grinding a substrate is disclosed. The temporary fixing strip has a supporting substrate and an adhesive layer stacked on one side of the supporting substrate. The supporting substrate has a first layer that supports the substrate and a second layer that is located between the first layer and the adhesive layer and has a buffering function. When the substrate with a protrusion on at least one surface is joined to the adhesive layer, the front end of the protrusion penetrates the adhesive layer and is located in the second layer. When the adhesive force of the adhesive layer after being irradiated by the energy ray is set to F1 [N / 25mm] and the adhesive force of the second layer is set to F2 [N / 25mm], the relationship F1 > F2 is satisfied.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2020-77799 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] According to the temporary fixing strip in Patent Document 1, the protrusions provided on the surface of the substrate penetrate the adhesive layer and become located in a second layer equivalent to the intermediate layer. As a result, uniform pressing pressure can be applied to the entire surface of the substrate, thus allowing it to be thinned with uniform thickness.

[0014] As in the technology of Patent Document 1, by forming an intermediate layer in a semiconductor processing adhesive sheet and embedding the protrusion of the adhered object in the intermediate layer, there is a tendency to suppress the generation of protrusions on the substrate side surface of the semiconductor processing adhesive sheet.

[0015] However, in cases where the protrusion is large in height or area, simply embedding the protrusion in the interlayer may not be sufficient to suppress the formation of protrusions. Furthermore, increasing the embedding depth reduces the mechanical strength of the interlayer, sometimes resulting in insufficient protection around the protrusion, or a portion of the interlayer adhering to the protrusion periphery after peeling. Therefore, there are limitations to suppressing the formation of protrusions on semiconductor processing adhesive sheets bonded to semiconductor wafers with protrusions simply by embedding the protrusion in the interlayer.

[0016] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a method for manufacturing a semiconductor device that can reduce the height difference between the protrusions and non-protrusions generated on a semiconductor processing adhesive sheet bonded to a semiconductor wafer having protrusions, thereby improving the processing accuracy of the semiconductor wafer, and a semiconductor wafer with a semiconductor processing adhesive sheet that can be used in the manufacturing method.

[0017] Methods for solving problems

[0018] The inventors conducted in-depth research and found that the above-mentioned problems could be solved by the following method, thereby completing the following invention. The method includes: using a semiconductor processing adhesive sheet having a substrate, an intermediate layer and an adhesive layer in sequence, and having one or more layers selected from the substrate, the intermediate layer and the adhesive layer as thermally expandable layers containing thermally expandable particles, and partially expanding the semiconductor processing adhesive sheet by a specific method.

[0019] That is, the present invention relates to the following [1] to

[14] .

[0020] [1] A method for manufacturing a semiconductor device, comprising using a semiconductor processing adhesive sheet having a substrate, an intermediate layer and an adhesive layer in sequence, wherein one or more layers selected from the substrate, the intermediate layer and the adhesive layer are thermally expandable layers containing thermally expandable particles, and the method for manufacturing the semiconductor device comprises the following steps 1 to 4.

[0021] Step 1: A step of attaching the semiconductor processing adhesive sheet to the surface (Wα) of a semiconductor wafer (W) having a protrusion, with the adhesive layer as the adhesive surface;

[0022] Step 2: On the substrate side surface (Sα) of the pasted semiconductor processing adhesive sheet, a cooling material is brought into contact with the upper surface of the protrusion in both the protrusion and non-protrusion portions, wherein the protrusion is generated by the protrusion and the non-protrusion is the portion other than the protrusion.

[0023] Step 3: While in contact with the cooling material, the semiconductor wafer (W) with protrusions is heated to above the expansion start temperature (t) of the thermally expanding particles. Thus, the semiconductor processing adhesive sheet is heated from the semiconductor wafer (W) side with protrusions. Through the cooling effect of the cooling material, the expansion of the portion of the semiconductor processing adhesive sheet with the protrusions as its surface is suppressed, while the portion with the non-protrusions as its surface is expanded, thereby reducing the height difference between the protrusions and the non-protrusions.

[0024] Step 4: A step of processing the semiconductor wafer (W) with protrusions while the substrate of the semiconductor processing adhesive sheet is fixed.

[0025] [2] According to the semiconductor device manufacturing method described in [1] above, wherein,

[0026] The thermal conductivity of the cooling material at 20°C is above 50 W / m·K.

[0027] [3] The method for manufacturing a semiconductor device according to [1] or [2] above, wherein,

[0028] The cooling material is metal.

[0029] [4] The method for manufacturing a semiconductor device according to any one of [1] to [3] above, wherein,

[0030] The thickness of the cooling material is more than 100 times the thickness of the thermal expansion layer.

[0031] [5] The method for manufacturing a semiconductor device according to any one of [1] to [4] above, wherein,

[0032] The thickness of the intermediate layer is 10–500 μm.

[0033] [6] The method for manufacturing a semiconductor device according to any one of [1] to [5] above, wherein,

[0034] The thickness of the adhesive layer is 1–80 μm.

[0035] [7] The method for manufacturing a semiconductor device according to any one of [1] to [6] above, wherein,

[0036] The content of the thermally expandable particles is 0.05 to 25% by mass relative to the total mass (100% by mass) of the thermally expandable layer.

[0037] [8] The method for manufacturing a semiconductor device according to any one of [1] to [7] above, wherein,

[0038] The expansion initiation temperature (t) of the thermally expandable particles is above 50°C and below 125°C.

[0039] [9] The method for manufacturing a semiconductor device according to any one of [1] to [8] above, wherein,

[0040] The intermediate layer is the thermal expansion layer.

[0041]

[10] The method for manufacturing a semiconductor device according to any one of [1] to [9] above, wherein,

[0042] The heating of the semiconductor wafer (W) with protrusions in step 3 is performed by heating the side (Wβ) of the semiconductor wafer (W) opposite to the side (Wα).

[0043]

[11] The method for manufacturing a semiconductor device according to any one of [1] to

[10] above, wherein,

[0044] The height of the protrusion is 10–500 μm.

[0045]

[12] The method for manufacturing a semiconductor device according to any one of [1] to

[11] above, wherein,

[0046] The semiconductor wafer (W) with protrusions is a semiconductor wafer with bumps as the protrusions.

[0047]

[13] According to the semiconductor device manufacturing method described in

[12] above, wherein,

[0048] The processing in step 4 is back-side grinding of the semiconductor wafer with the bumps.

[0049]

[14] A semiconductor wafer with a semiconductor processing adhesive sheet is formed by attaching the semiconductor processing adhesive sheet, which sequentially comprises a substrate, an intermediate layer and an adhesive layer, to the surface (Wa) of a semiconductor wafer (W) having a protrusion, with the adhesive layer as the adhesive surface, wherein,

[0050] The semiconductor processing adhesive sheet, when viewed from above, has the following characteristics:

[0051] Regions with or without gaps (a) and

[0052] Region (b) has a higher volumetric porosity than region (a) and a greater thickness than region (a).

[0053] The surface (Sα) on the substrate side is planarized by the thickness difference between region (a) and region (b).

[0054] The effects of the invention

[0055] According to the present invention, a method for manufacturing a semiconductor device can be provided that can reduce the height difference between protrusions and non-protrusions generated on a semiconductor processing adhesive sheet bonded to a semiconductor wafer having protrusions, thereby improving the processing accuracy of the semiconductor wafer, and a semiconductor wafer with a semiconductor processing adhesive sheet can be used in the manufacturing method. Attached Figure Description

[0056] Figure 1 This is a cross-sectional view showing an example of the structure of an adhesive sheet for semiconductor processing.

[0057] Figure 2 This is a top view used to illustrate a semiconductor wafer (W) with protrusions.

[0058] Figure 3 This is a cross-sectional view illustrating an example of a process in the manufacturing method of the semiconductor device of the present invention.

[0059] Figure 4 This is a cross-sectional view illustrating an example of a process in the manufacturing method of the semiconductor device of the present invention.

[0060] Figure 5 This is a cross-sectional view illustrating an example of a process in the manufacturing method of the semiconductor device of the present invention.

[0061] Figure 6 This is a cross-sectional view illustrating an example of a process in the manufacturing method of the semiconductor device of the present invention.

[0062] Symbol Explanation

[0063] 1. Substrate

[0064] 2. Intermediate layer

[0065] 3 Adhesive layer

[0066] 4. Peeling tablets

[0067] 5. Pre-defined dividing line

[0068] 6 Devices

[0069] 7. Bumps

[0070] 8 Device Area

[0071] 9. Non-forming regions of the device

[0072] 10, 10a, 10b Adhesive sheets for semiconductor processing

[0073] 11 convex part

[0074] 11' is part of the protrusion 11

[0075] 12 non-convex parts

[0076] 12' Non-convex portion 12 Expanded portion

[0077] 13 Cooling materials

[0078] 14 Heating Plate

[0079] 15 Supporting devices

[0080] 16 Grinding machine

[0081] W Adhesive

[0082] Wα The side of the adhered object

[0083] Wβ The other side of the adhered material

[0084] The substrate side surface of the Sα adhesive sheet 10

[0085] The surface of the cooling material in contact with the substrate side surface Sα of Cα Detailed Implementation

[0086] In this specification, the lower limit and upper limit values ​​of the preferred numerical ranges can be combined independently. For example, based on the description of "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 set "10 to 60".

[0087] In this specification, for example, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and so on.

[0088] In this specification, "energy rays" refers to rays that possess energy quanta within electromagnetic waves or beams of charged particles. Examples of such rays include ultraviolet light, radiation, and electron beams. Ultraviolet light can be emitted by sources such as electrodeless lamps, high-pressure mercury lamps, metal halide lamps, and UV-LEDs. Electron beams can be emitted by irradiating electron beams generated by electron beam accelerators or similar devices.

[0089] In this specification, "energy-ray polymerizability" refers to the property of polymerization occurring upon irradiation with energy rays. Similarly, "energy-ray curing property" refers to the property of curing occurring upon irradiation with energy rays.

[0090] In this specification, whether a “layer” is a “non-thermal expansion layer” or a “thermal expansion layer” is determined as follows.

[0091] If the layer to be judged contains thermally expandable particles, the layer is heated for 3 minutes at the expansion start temperature (t) of the thermally expandable particles. If the volume change rate calculated according to the following formula is less than 5%, the layer is judged as a "non-thermally expandable layer"; if it is 5% or more, the layer is judged as a "thermally expandable layer".

[0092] • 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

[0093] It should be noted that layers that do not contain thermally expanding particles are considered "non-thermally expanding layers".

[0094] In this specification, when the "layer" is a non-thermal expansion layer, the volume change rate (%) of the non-thermal expansion layer calculated according to 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%.

[0095] Furthermore, in this specification, when the "layer" is a non-thermally expandable layer, the non-thermally expandable layer preferably does not contain thermally expandable particles, but it may contain thermally expandable particles within a range that does not depart from the purpose of the present invention. When the non-thermally expandable layer contains thermally expandable particles, the lower the content, the more preferred. Relative to the total mass (100% by mass) of the non-thermally expandable layer, 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.

[0096] In this specification, the “circuit side” of a semiconductor wafer refers to the side on which a circuit is formed, and the “back side” of a semiconductor wafer refers to the side on which no circuit is formed.

[0097] In this specification, "semiconductor device" refers to any device capable of functioning by utilizing the characteristics of semiconductors. Examples include wafers with integrated circuits, thinned wafers with integrated circuits, chips with integrated circuits, thinned chips with integrated circuits, electronic components containing these chips, and electronic devices containing such electronic components.

[0098] In this specification, the thickness of each layer refers to the thickness at 23°C, which is the value measured by the method described in the examples.

[0099] The mechanisms of action described in this specification are speculative and do not limit the mechanisms by which the present invention achieves its effects.

[0100] [Semiconductor Device Manufacturing Method]

[0101] One aspect of the present invention provides a method for manufacturing a semiconductor device, which uses a semiconductor processing adhesive sheet having a substrate, an intermediate layer and an adhesive layer in sequence, wherein one or more of the substrate, the intermediate layer and the adhesive layer are thermally expandable layers containing thermally expandable particles, and the method for manufacturing the semiconductor device includes the following steps 1 to 4.

[0102] Step 1: A step of attaching the above-mentioned semiconductor processing adhesive sheet to the surface (Wα) of the semiconductor wafer (W) having the protrusion, using the above-mentioned adhesive layer as the bonding surface.

[0103] Step 2: On the substrate side surface (Sα) of the above-mentioned bonded semiconductor processing adhesive sheet, a cooling material is brought into contact with the upper surface of the protrusion, which is formed by the protrusion and the non-protrusion is the portion other than the protrusion.

[0104] Step 3: While in contact with the cooling material, the semiconductor wafer (W) with protrusions is heated to above the expansion start temperature (t) of the thermally expanding particles. This heats the semiconductor processing adhesive sheet from the semiconductor wafer (W) side. Through the cooling effect of the cooling material, the expansion of the portion of the semiconductor processing adhesive sheet with the protrusions as its surface is suppressed, while the portion with the non-protrusions as its surface expands, thus reducing the height difference between the protrusions and the non-protrusions.

[0105] Step 4: A step of processing the semiconductor wafer (W) with protrusions while the substrate of the above-mentioned semiconductor processing adhesive sheet is fixed.

[0106] Hereinafter, the semiconductor processing adhesive sheet used in a method for manufacturing a semiconductor device according to one aspect of the present invention will be described first, and then the various steps included in the method for manufacturing a semiconductor device according to one aspect of the present invention will be described in detail.

[0107] <Adhesive Sheets for Semiconductor Processing>

[0108] One embodiment of the present invention is an adhesive sheet for semiconductor processing (hereinafter also simply referred to as "adhesive sheet") having a substrate, an intermediate layer and an adhesive layer in sequence.

[0109] In one embodiment of the invention, an adhesive sheet is attached to the protruding surface (Wα) of a semiconductor wafer (W) to protect the surface and to allow for a given processing of the semiconductor wafer (W). Then, after the given processing of the semiconductor wafer (W) has been performed, the adhesive sheet of one embodiment of the invention is peeled off.

[0110] Figure 1 (a) shows an adhesive sheet as one aspect of the present invention, which is an adhesive sheet 10a having a substrate 1, an intermediate layer 2 and an adhesive layer 3 stacked in sequence.

[0111] One embodiment of the adhesive sheet of the present invention, such as adhesive sheet 10a, may have only a substrate, an intermediate layer, and an adhesive layer, or may have other layers as needed. Examples of other layers include, for instance, a release sheet disposed on the side of the adhesive layer opposite to the intermediate layer.

[0112] Figure 1 (b) An adhesive sheet 10b of the present invention is shown, having a release tab 4 as another layer. In the adhesive sheet 10b, the release tab 4 is laminated on the adhesive surface of the adhesive layer 3.

[0113] Next, a preferred embodiment of the layers of the adhesive sheet according to one aspect of the present invention will be described.

[0114] (Thermal expansion layer)

[0115] In one embodiment of the present invention, the adhesive sheet is selected from a substrate, an intermediate layer and an adhesive layer, and one or more of these layers are thermally expandable layers containing thermally expandable particles.

[0116] One embodiment of the adhesive sheet of the present invention may have two or more thermally expandable layers, preferably only one layer. In the case where the adhesive sheet of one embodiment of the present invention has two or more thermally expandable layers, there may be layers other than thermally expandable layers between the thermally expandable layers, or there may be no layers other than thermally expandable layers between the thermally expandable layers.

[0117] In one embodiment of the present invention, the adhesive sheet preferably has an intermediate layer that is thermally expandable, and more preferably has an intermediate layer that is thermally expandable while the substrate and adhesive layer are non-thermally expandable. When the intermediate layer is thermally expandable and the substrate and adhesive layer are non-thermally expandable, the irregularities caused by the thermally expandable particles are less likely to be exposed on the surface of the adhesive layer or the substrate, and there is a tendency for good adhesion to the semiconductor wafer (W) or good retention when held using a support device such as a chuck stage.

[0118] The thickness of the thermal expansion layer is not particularly limited, as long as it is appropriately determined which of the layers in the adhesive sheet according to one aspect of the invention is the thermal expansion layer.

[0119] It should be noted that, in this specification, the term "thickness of the thermally expandable layer" refers to the total thickness of all thermally expandable layers in an adhesive sheet according to one embodiment of the present invention. For example, if only one of the substrate, intermediate layer, and adhesive layer in an adhesive sheet according to one embodiment of the present invention is a thermally expandable layer, the thickness of that layer is the thickness of the thermally expandable layer. Furthermore, if two or more of the substrate, intermediate layer, and adhesive layer in an adhesive sheet according to one embodiment of the present invention are thermally expandable layers, the total thickness of those two or more layers is the thickness of the thermally expandable layer.

[0120] [Particles with thermal expansion]

[0121] Thermally expandable particles are simply particles that expand when heated.

[0122] One type of thermally expanding particle can be used alone, or two or more types can be used in combination.

[0123] The expansion initiation temperature (t) of the thermally expandable particles is preferably 50°C or higher and lower than 125°C, more preferably 55–120°C, further preferably 60–115°C, even more preferably 70–110°C, and even more preferably 75–105°C. When the expansion initiation temperature (t) of the thermally expandable particles is 50°C or higher, there is a tendency to easily suppress unexpected expansion. In addition, when the expansion initiation temperature (t) of the thermally expandable particles is lower than 125°C, the heating temperature during heat-peeling can be suppressed to a lower level.

[0124] It should be noted that, in this specification, the expansion start temperature (t) of thermally expandable particles refers to a value measured based on the following method.

[0125] (Method for determining the expansion start temperature (t) of thermally expandable particles)

[0126] 0.5 mg of thermally expandable particles, which are the test objects, are added to an aluminum cup with a diameter of 6.0 mm (inner diameter of 5.65 mm) and a depth of 4.8 mm to prepare a sample with an aluminum lid (diameter of 5.6 mm and thickness of 0.1 mm) placed on top of it.

[0127] 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 through a pressure head from the top of the aluminum cap. Then, while a force of 0.01 N was applied through the pressure head, the sample was heated from 20 °C to 300 °C at a heating rate of 10 °C / min, and the displacement of the pressure head in the vertical direction was measured. The temperature at which the displacement in the positive direction began was taken as the expansion initiation temperature (t).

[0128] As a thermally expandable particle, a microencapsulated foaming agent is preferably composed of an outer shell and an inner component encapsulated within the outer shell, the outer shell being made of a thermoplastic resin, and the inner component vaporizing when heated to a given temperature.

[0129] Examples of thermoplastic resins constituting the outer shell of microencapsulated foaming agents include: polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, or copolymers obtained by polymerizing two or more monomers that form the structural units contained in these thermoplastic resins.

[0130] The inner component, which is the component encapsulated within the shell of the microencapsulated foaming agent, can be exemplified by low-boiling-point liquids such as propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, n-heptane, n-octane, cyclopropane, cyclobutane, and petroleum ether. From the viewpoint of suppressing unexpected expansion and keeping the heating temperature during heat stripping to a low level, propane, isobutane, n-pentane, and cyclopropane are preferred as the inner component, provided that the expansion start temperature (t) of the thermally expandable particles is set to 50°C or higher and below 125°C.

[0131] These inner components can be used alone or in combination of two or more.

[0132] The expansion initiation temperature (t) of thermally expandable particles can be adjusted by appropriately selecting the type of internal components.

[0133] The average particle size of the thermally expandable particles before expansion at 23°C is preferably 3–100 μm, more preferably 4–70 μm, further preferably 6–60 μm, and even more preferably 10–50 μm.

[0134] It should be noted that the average particle size of thermally expandable particles before expansion is the volume median particle size (D). 50 The cumulative volume frequency, calculated from the side with the smallest particle size of the thermally expandable particles before expansion, is equivalent to 50% of the particle size in the particle distribution before expansion, as measured using a laser diffraction particle size distribution measuring device (e.g., Malvern's Mastersizer 3000).

[0135] 90% of the particle size (D) of thermally expandable particles before expansion at 23°C 90 The preferred size is 10–150 μm, more preferably 15–100 μm, further preferably 20–90 μm, and even more preferably 25–80 μm.

[0136] It should be noted that the 90% particle size (D) before expansion of thermally expandable particles 90 This refers to the cumulative volumetric frequency, calculated from the side with the smallest particle size of the thermally expandable particles before expansion, 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"). This frequency corresponds to 90% of the particle size.

[0137] In one embodiment of the present invention, the maximum volume expansion rate of the thermally expandable particles when heated to a temperature above the expansion start 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.

[0138] The content of thermally expandable particles relative to the total mass (100% by mass) of the thermally expandable layer is preferably 0.05 to 25% by mass, more preferably 0.1 to 15% by mass, further preferably 0.2 to 10% by mass, and even more preferably 0.3 to 5% by mass. When the content of thermally expandable particles is 0.05% by mass or more, there is a tendency to easily flatten the protrusions of the adhesive sheet caused by the protrusions of the semiconductor wafer (W). In addition, when the content of thermally expandable particles is 25% by mass or less, the unevenness of the thermally expandable particles before thermal expansion is less likely to be exposed on the surface of the adhesive layer or the substrate, and there is a tendency to improve the adhesion to the semiconductor wafer (W) or the retention by a support device such as a chuck stage.

[0139] (Substrate)

[0140] As one embodiment of the present invention, the substrate used can be made of any material capable of supporting a semiconductor wafer (W), and there are no particular limitations.

[0141] The substrate is preferably a non-adhesive substrate.

[0142] The probe adhesion value of the substrate surface is typically less than 50 mN / 5 mmφ, preferably less than 30 mN / 5 mmφ, more preferably less than 10 mN / 5 mmφ, and even more preferably less than 5 mN / 5 mmφ.

[0143] It should be noted that, in this specification, the probe adhesion value of the substrate surface refers to the value measured by the following method.

[0144] <Probe viscosity value>

[0145] The substrate to be tested can be cut into squares with sides of 10 mm and left to stand for 24 hours at 23°C and 50% RH (relative humidity) to prepare test samples. The probe viscosity value of the surface of the test samples is then measured using a viscosity testing machine (manufactured by Nippon Special Test Instruments Co., Ltd., product name "NTS-4800") at 23°C and 50% RH (relative humidity) according to JIS Z0237:1991. Specifically, the viscosity can be measured at a contact load of 0.98 N / cm for 1 second. 2 After a stainless steel probe with a diameter of 5 mm is brought into contact with the surface of the test sample, the force required to remove the probe from the surface of the test sample at a speed of 10 mm / s is measured, and the obtained value is taken as the probe viscosity value of the test sample.

[0146] Materials used as base materials include, for example, resin, metal, and paper.

[0147] 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.

[0148] Examples of metals include aluminum, tin, chromium, and titanium.

[0149] Examples of paper materials include: thin paper, medium-quality paper, high-quality paper, coated paper, art paper, tracing paper, and cellophane.

[0150] The preferred resins are polyester resins such as polyethylene terephthalate (hereinafter also referred to as "PET"), polybutylene terephthalate, and polyethylene naphthalate.

[0151] These forming materials can consist of one type or a combination of two or more types.

[0152] Examples of substrates formed by combining two or more forming materials include: substrates obtained by laminating paper materials with thermoplastic resins such as polyethylene, and substrates in which a metal film is formed on the surface of a resin film or sheet containing resin. It should be noted that methods for forming the metal layer include: methods for depositing the aforementioned metal using PVD methods such as vacuum evaporation, sputtering, or ion plating, or methods for bonding a metal foil formed from the aforementioned metal using a common adhesive.

[0153] It should be noted that, from the viewpoint of improving the interlayer adhesion between the substrate and other layers to be laminated, when the substrate contains resin, the surface of the substrate can be subjected to surface treatments such as oxidation, texturing, easy-to-adhere treatments, or primer treatments.

[0154] Depending on the requirements, the substrate may contain substrate additives. Examples of substrate additives include: ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, lubricants, anti-blocking agents, and colorants. It should be noted that these substrate additives may be used individually or in combination of two or more.

[0155] When the substrate is a thermally expandable layer containing thermally expandable particles (hereinafter also referred to as "thermally expandable substrate"), the substrate can be formed by a substrate composition containing resin and thermally expandable particles.

[0156] The preferred method for the type and content of thermally expandable particles is the same as the preferred method for the type and content of thermally expandable particles in the description of the thermally expandable layer above.

[0157] The type of resin contained in the composition for the substrate is preferably a urethane resin or an olefin resin among the types of resins mentioned above, more preferably a urethane resin, and even more preferably an acrylic-modified polyurethane.

[0158] When the substrate composition contains acrylic-modified polyurethane, the substrate composition may be a solvent-free resin composition that contains, in addition to acrylic-modified polyurethane and thermally expandable particles, energy-ray polymerizable monomers, photopolymerization initiators, etc., and does not contain a solvent.

[0159] In solvent-free resin compositions, although no solvent is used, energy-ray polymerizable monomers help improve plasticity. By irradiating the solvent-free resin composition with energy rays, acrylic-modified polyurethane, energy-ray polymerizable monomers, etc., can be polymerized to form a thermally expandable substrate.

[0160] As polymerizable monomers and photopolymerization initiators for energy rays, examples include substances that are the same polymerizable monomers and photopolymerization initiators optionally contained in the intermediate layer compositions described later.

[0161] The substrate can be a substrate laminate formed by laminating a thermally expandable substrate with a non-thermally expandable substrate (hereinafter also referred to as "non-thermally expandable substrate").

[0162] When the substrate is the above-mentioned substrate laminate, the thermally expandable substrate may be disposed on the intermediate layer side and the non-thermally expandable substrate may be disposed on the side opposite to the intermediate layer side, or the non-thermally expandable substrate may be disposed on the intermediate layer side and the thermally expandable substrate may be disposed on the side opposite to the intermediate layer side.

[0163] When a non-thermally expandable substrate is placed on the side opposite to the interlayer side, the unevenness caused by the expanded thermally expandable particles is less likely to be exposed on the surface opposite to the interlayer side, and the holding properties provided by support devices such as chuck tables tend to become better. On the other hand, when a non-thermally expandable substrate is placed on the interlayer side, there is a tendency to easily control the unexpected expansion of the thermally expandable substrate due to frictional heat during the processing of the adhered object (W).

[0164] The thickness of the substrate 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 is 5 μm or more, there is a tendency to easily improve the deformation resistance of the adhesive sheet. In addition, when the thickness of the substrate is 500 μm or less, there is a tendency to easily improve the processability of the adhesive sheet.

[0165] It should be noted that the thickness of the substrate refers to the overall thickness of the substrate. For example, the thickness of a substrate composed of multiple layers refers to the total thickness of all the layers that make up the substrate.

[0166] (Middle layer)

[0167] The intermediate layer is a layer disposed between the substrate and the adhesive layer.

[0168] The composition of the intermediate layer is not particularly limited, but the intermediate layer is preferably formed from a resin-containing intermediate layer composition.

[0169] Examples of resins contained in compositions used as intermediate layers include urethane (meth)acrylates and acrylic resins.

[0170] [Carbamate (meth)acrylate]

[0171] Carbamate (meth)acrylates are compounds having at least a (meth)acryloyl group and a carbamate bond, and possess the property of being polymerized by irradiation with energy rays. By including carbamate (meth)acrylates in the composition for the intermediate layer, there is a tendency for the resulting intermediate layer to have improved flexibility.

[0172] Carbamate (meth)acrylates can be used alone or in combination of two or more.

[0173] The urethane (meth) acrylate can be a monofunctional urethane (meth) acrylate or a polyfunctional urethane (meth) acrylate, preferably a polyfunctional urethane (meth) acrylate, and more preferably a difunctional urethane (meth) acrylate.

[0174] The weight-average molecular weight (Mw) of the urethane (meth)acrylate is preferably 10,000 to 100,000, more preferably 20,000 to 90,000, further preferably 25,000 to 70,000, and even more preferably 30,000 to 60,000.

[0175] Carbamate (meth)acrylates can be obtained, for example, by reacting a polyol compound with a polyisocyanate compound and then reacting the resulting terminal isocyanate carbamate prepolymer with a (meth)acrylate having hydroxyl groups.

[0176] Examples of polyol compounds include: alkylene polyols, ether polyols, ester polyols, esteramide polyols, ester / ether polyols, carbonate polyols, etc.

[0177] Polyol compounds can be used alone or in combination of two or more.

[0178] Examples of polyisocyanates include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. Furthermore, these polyisocyanates can be trimethylolpropane addition-type modifiers, biuret-type modifiers resulting from water reaction, and isocyanurate-type modifiers containing isocyanurate rings.

[0179] Polyisocyanates can be used alone or in combination of two or more.

[0180] Examples of (meth)acrylates having 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, etc.

[0181] (Meth)acrylates containing hydroxyl groups can be used alone or in combination of two or more.

[0182] The content of urethane (meth)acrylate in the intermediate layer composition is preferably 20-90% by mass, more preferably 35-80% by mass, and even more preferably 50-70% by mass, relative to the total amount (100% by mass) of the active ingredients in the intermediate layer composition.

[0183] [Acrylic resins]

[0184] Acrylic resins that can be used as resins contained in compositions for use as intermediate layers include the same acrylic resins that can be used as adhesive resins for adhesive layers as described later.

[0185] The composition for the intermediate layer more preferably contains polymeric monomers other than the aforementioned urethane (meth) acrylate and urethane (meth) acrylate.

[0186] [Polymerizable monomers]

[0187] The polymerizable monomer is preferably a polymerizable compound other than a urethane (meth)acrylate, which is a compound that can be polymerized with other components by irradiation with energy rays. Specifically, the polymerizable monomer is preferably a compound having at least one (meth)acryloyl group.

[0188] Polymerizable monomers can be used alone or in combination of two or more.

[0189] Examples of polymerizable monomers include: (meth)acrylates having alkyl groups with 1 to 30 carbon atoms; (meth)acrylates having functional groups such as hydroxyl, amide, amino, and epoxy groups; (meth)acrylates having alicyclic structures; (meth)acrylates having aromatic structures; (meth)acrylates having heterocyclic structures; vinyl compounds such as styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, and N-vinylcaprolactam; allyl compounds such as allyl glycidyl ether; etc.

[0190] Examples of (meth)acrylates having alkyl groups having 1 to 30 carbon atoms include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, eicosyl methacrylate, etc.

[0191] The (meth)acrylate having an alkyl group having 1 to 30 carbon atoms preferably has 4 to 24 carbon atoms, more preferably 8 to 18 carbon atoms, and even more preferably 10 to 14 carbon atoms.

[0192] Examples of (meth)acrylates with functional groups include: hydroxyl-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; amide-containing compounds such as (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide; amino-containing (meth)acrylates such as (meth)acrylates containing primary amino groups, (meth)acrylates containing secondary amino groups, and (meth)acrylates containing tertiary amino groups; and glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate.

[0193] Examples of (meth)acrylates having an alicyclic structure include isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, and adamantane (meth)acrylate. Among these, isobornyl (meth)acrylate and trimethylcyclohexyl (meth)acrylate are preferred.

[0194] Examples of (meth)acrylates having an aromatic structure include: phenyl hydroxypropyl (meth)acrylate, benzyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, etc.

[0195] Examples of (meth)acrylates having a heterocyclic structure include tetrahydrofurfuryl (meth)acrylate and morpholine (meth)acrylate.

[0196] Among the above options for polymerizable monomers, the composition for the intermediate layer preferably contains (meth)acrylates having alkyl groups having 1 to 30 carbon atoms and (meth)acrylates having an alicyclic structure.

[0197] The content of (meth)acrylate having an alkyl group having 1 to 30 carbon atoms in the intermediate layer composition is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and even more preferably 5 to 15% by mass, relative to the total amount (100% by mass) of the active ingredient in the intermediate layer composition.

[0198] The content of (meth)acrylates having an alicyclic structure in the intermediate layer composition is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 30% by mass, relative to the total amount (100% by mass) of the active ingredients in the intermediate layer composition.

[0199] The total content of polymerizable monomers in the intermediate layer composition is preferably 8 to 70% by mass, more preferably 15 to 50% by mass, and even more preferably 30 to 40% by mass, relative to the total amount of the active ingredients in the intermediate layer composition (100% by mass).

[0200] The ratio of urethane (meth)acrylate content to polymerizable monomer content in the composition for the intermediate layer (urethane (meth)acrylate / polymerizable monomer) is preferably 20 / 80 to 90 / 10 by mass, more preferably 40 / 60 to 80 / 20, and even more preferably 60 / 40 to 70 / 30.

[0201] [Photopolymerization initiator]

[0202] The preferred intermediate layer composition contains urethane (meth)acrylate and polymerizable monomers, and further contains a photopolymerization initiator. By including a photopolymerization initiator in the intermediate layer composition, the curing reaction can be fully carried out even when irradiated by low-energy rays.

[0203] Photopolymerization initiators can be used alone or in combination of two or more.

[0204] Examples of photopolymerization initiators include: benzoin compounds, acetophenone compounds, phosphine oxide compounds, titanium cinnamate compounds, thioxanone compounds, peroxide compounds, and photosensitizers such as amines and quinones.

[0205] More specifically, examples include: 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, etc.

[0206] The content of photopolymerization initiator in the composition for the intermediate layer is preferably 0.05 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, relative to a total of 100 parts by mass of urethane (meth)acrylate and polymerizable monomers.

[0207] [Chain transfer agent]

[0208] The preferred intermediate layer composition contains urethane (meth)acrylate and polymerizable monomers, and further contains a chain transfer agent. By including a chain transfer agent in the intermediate layer composition, components with short molecular chains may remain even after curing, and the cured polymer has flexibility.

[0209] Chain transfer agents can be used alone or in combination of two or more.

[0210] Examples of chain transfer agents include compounds containing thiol groups. Examples of thiol-containing compounds include: nonylthiol, 1-dodecylthiol, 1,2-ethanedithiol, 1,3-propanedithiol, triazine thiol, triazine dithiol, triazine trithiol, 1,2,3-propanetrithiol, tetraethylene glycol bis(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetrathioglycolate, dipentaerythritol hexa(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, 1,4-bis(3-mercaptobutyryloxy)butane, pentaerythritol tetra(3-mercaptobutyrylate), 1,3,5-tris(3-mercaptobutoxyethyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, etc. The preferred option is pentaerythritol tetra(3-mercaptobutyrate).

[0211] The content of chain transfer agent in the intermediate layer composition is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to a total of 100 parts by mass of urethane (meth)acrylate and polymerizable monomers.

[0212] [Particles with thermal expansion]

[0213] When the intermediate layer is a thermally expandable layer containing thermally expandable particles, the intermediate layer can be formed by using a composition containing thermally expandable particles. The preferred methods for the type and content of thermally expandable particles are the same as those for the type and content of thermally expandable particles described above in the description of thermally expandable layers.

[0214] [Additives for the intermediate layer]

[0215] Without impairing the effects of the present invention, in addition to the components described above, the intermediate layer composition may also contain intermediate layer additives. Examples of intermediate layer additives include: antioxidants, plasticizers, fillers, rust inhibitors, pigments, dyes, and tackifiers.

[0216] It should be noted that these intermediate layer additives can be used individually or in combination of two or more.

[0217] When the intermediate layer composition contains these intermediate layer additives, the content of each intermediate layer additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, relative to a total of 100 parts by mass of urethane (meth)acrylate and polymerizable monomers.

[0218] Without impairing the effects of the invention, the intermediate layer composition used in one embodiment of the invention may contain a solvent, but is preferably a solvent-free resin composition containing urethane (meth)acrylate and polymerizable monomers and containing no solvent.

[0219] Although the solvent-free resin composition does not contain solvents, the aforementioned polymerizable monomers help to improve the plasticity of the resin.

[0220] By irradiating the solvent-free resin composition with energy rays, urethane (meth)acrylate, polymerizable monomers, etc., polymerize to form an intermediate layer.

[0221] [Thickness of the intermediate layer]

[0222] In one embodiment of the adhesive sheet of the present invention, the thickness of the intermediate layer is preferably 10 to 500 μm, more preferably 20 to 350 μm, and even more preferably 30 to 200 μm. When the thickness of the intermediate layer is 10 μm or more, it tends to facilitate the embedding of protrusions of the semiconductor wafer (W). In addition, when the thickness of the intermediate layer is 500 μm or less, it tends to improve the operability of the adhesive sheet.

[0223] It should be noted that the thickness of the intermediate layer refers to the overall thickness of the intermediate layer. For example, the thickness of an intermediate layer composed of multiple layers refers to the total thickness of all the layers that make up the intermediate layer.

[0224] (Adhesive layer)

[0225] The adhesive layer is a layer disposed on the side opposite to the substrate of the intermediate layer, and is a layer that is adhered to the protruding side (Wα) of the semiconductor wafer (W).

[0226] The adhesive layer is preferably a layer that can be cured by energy rays. By making the adhesive layer curable by energy rays, the surface of the semiconductor wafer (W) can be well protected by sufficient adhesion before energy ray curing, and the peel force is reduced after energy ray curing, making it easy to peel off from the semiconductor wafer (W).

[0227] The adhesive layer can be formed from an adhesive composition containing an adhesive resin.

[0228] Examples of adhesive compositions include, for example, type X adhesive compositions, type Y adhesive compositions, type XY adhesive compositions, etc.

[0229] X-type adhesive composition: an energy-ray curable adhesive composition containing a non-energy-ray curable adhesive resin (hereinafter also referred to as "Adhesive Resin I") and energy-ray curable compounds other than the adhesive resin.

[0230] Type Y adhesive composition: an energy-curable adhesive composition containing an energy-curable adhesive resin (hereinafter also referred to as "Adhesive Resin II") with unsaturated groups introduced into the side chains of a non-energy-curable adhesive resin, and free of energy-curable compounds other than the adhesive resin.

[0231] XY type adhesive composition: an energy-ray curable adhesive composition containing the above-mentioned energy-ray curable adhesive resin II and energy-ray curable compounds other than the adhesive resin.

[0232] Among them, the energy-curable adhesive is preferably an XY type adhesive composition.

[0233] Next, the components that make up the adhesive layer will be explained in more detail.

[0234] In the following description, "adhesive resin" is used to refer to one or both of adhesive resin I and adhesive resin II.

[0235] The adhesive resin can be an adhesive resin without functional groups, but it is preferred to be an adhesive resin with functional groups. By giving the adhesive resin functional groups, for example, reactivity with the crosslinking agent described later, energy ray curing properties, etc., can be obtained.

[0236] Examples of functional groups found in adhesive resins include: unsaturated groups with energy-ray polymerization properties such as (meth)acryloyl, vinyl, and allyl groups; and hydroxyl, carboxyl, amino, and epoxy groups. Among these, (meth)acryloyl and hydroxyl groups are preferred. Adhesive resins may have one type of functional group or two or more types of functional groups.

[0237] Examples of adhesive resins include acrylic resins, urethane resins, rubber resins, and silicone resins. Among these, acrylic resins are preferred.

[0238] [Acrylic resins]

[0239] Acrylic resins are any polymers containing acrylic monomers as monomer components, without particular limitations, but preferably contain structural units derived from (meth)acrylate alkyl esters.

[0240] Examples of alkyl (meth)acrylates include, for example, alkyl (meth)acrylates with alkyl groups having 1 to 20 carbon atoms.

[0241] The alkyl groups in (meth)acrylates can be either straight-chain or branched.

[0242] From the viewpoint of further improving the adhesion of the adhesive layer, acrylic resins preferably contain structural units of (meth)acrylate alkyl esters with 4 or more carbon atoms derived from alkyl groups.

[0243] The structural units of (meth)acrylate alkyl esters containing alkyl groups with 4 or more carbon atoms can be one or more.

[0244] The alkyl ester of (meth)acrylate having 4 or more carbon atoms preferably has 4 to 12 carbon atoms, more preferably 4 to 8, and even more preferably 4 to 6.

[0245] Alkyl esters of (meth)acrylate having 4 or more carbon atoms as the alkyl group include, for example, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, 2-ethylhexyl (meth)acrylate is preferred, and 2-ethylhexyl acrylate is more preferred.

[0246] From the viewpoint of further improving the adhesion of the adhesive layer, the content of alkyl (meth)acrylate with 4 or more carbon atoms is preferably 30 to 90% by mass, more preferably 40 to 80% by mass, and even more preferably 50 to 70% by mass in the structural units of the acrylic monomers constituting the acrylic resin.

[0247] From the viewpoint of achieving good elastic modulus and adhesive properties of the adhesive layer, it is preferable that the acrylic resin contains structural units of (meth)acrylate alkyl esters with 4 or more carbon atoms derived from alkyl groups, and structural units of (meth)acrylate alkyl esters with 1 to 3 carbon atoms derived from alkyl groups.

[0248] The structural units of alkyl (meth)acrylates containing alkyl groups with 1 to 3 carbon atoms can be one or more.

[0249] Alkyl methacrylates having 1 to 3 carbon atoms as the alkyl group include, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, and n-propyl methacrylate. Among these, methyl methacrylate and ethyl methacrylate are preferred, and methyl methacrylate and ethyl acrylate are more preferred.

[0250] The content of the structural unit of (meth)acrylate alkyl ester with 1 to 3 carbon atoms from the alkyl group is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, and even more preferably 15 to 25% by mass from the structural unit of the acrylic monomer constituting the acrylic resin.

[0251] Acrylic resins preferably further contain structural units derived from functionalized monomers.

[0252] By incorporating structural units from functionalized monomers into acrylic resins, functional groups that can serve as crosslinking initiation points for reaction with crosslinking agents, or functional groups that can react with compounds containing unsaturated groups to introduce unsaturated groups into the side chains of acrylic resins, can be introduced.

[0253] Acrylic resins contain one or more structural units derived from functional group monomers.

[0254] Examples of monomers containing functional groups include: hydroxyl monomers, carboxyl monomers, amino monomers, and epoxy monomers.

[0255] 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 alcohols and allyl alcohols; etc.

[0256] 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.

[0257] Preferably, it is a hydroxyl-containing monomer, more preferably 2-hydroxyethyl methacrylate, and even more preferably 2-hydroxyethyl acrylate.

[0258] The content of structural units from functional group monomers is preferably 1 to 35% by mass, more preferably 5 to 30% by mass, and even more preferably 15 to 25% by mass from the structural units from acrylic monomers constituting acrylic resins.

[0259] In addition to the structural units mentioned above, acrylic resins may also contain structural units from other monomers that can copolymerize with acrylic monomers.

[0260] Acrylic resins contain structural units derived from other monomers, which can be one or two or more.

[0261] Other monomers include, for example, styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, and acrylamide.

[0262] To further impart energy-ray curability, acrylic resins can be infused with unsaturated groups that have energy-ray polymerization properties.

[0263] For example, an unsaturated group can be introduced by reacting a functional group of an acrylic resin containing a structural unit derived from a functional group monomer with a reactive substituent and an unsaturated group (hereinafter also referred to as a "compound containing an unsaturated group") that is reactive to the functional group. A compound containing an unsaturated group can be used alone or in combination of two or more.

[0264] Examples of unsaturated groups in compounds containing unsaturated groups include (meth)acryloyl, vinyl, and allyl groups. Among these, (meth)acryloyl is preferred.

[0265] Examples of reactive substituents in compounds containing unsaturated groups include isocyanate groups and glycidyl groups.

[0266] Examples of compounds containing unsaturated groups include 2-(meth)acryloyloxyethyl isocyanate, (meth)acryloyl isocyanate, and (meth)acrylate glycidyl ester. Among these, 2-(meth)acryloyloxyethyl isocyanate is preferred, and more preferably 2-methacryloyloxyethyl isocyanate.

[0267] When an acrylic resin containing structural units derived from functional group monomers is reacted with a compound containing unsaturated groups, the ratio of the total number of functional groups in the acrylic resin to the functional groups that react with the compound containing unsaturated groups is not particularly limited, but is preferably 30 to 90 mol%, more preferably 40 to 80 mol%, and even more preferably 50 to 70 mol%.

[0268] When the ratio of functional groups that react with compounds containing unsaturated groups is within the above range, acrylic resins can be given sufficient energy-curable properties, and the acrylic resins can be crosslinked by reacting the functional groups that have not reacted with compounds containing unsaturated groups with a crosslinking agent.

[0269] The weight-average molecular weight (Mw) of acrylic resins is not particularly limited, but is preferably 300,000 to 1,500,000, more preferably 450,000 to 1,000,000, and even more preferably 600,000 to 900,000. When the weight-average molecular weight (Mw) of acrylic resins is within the above range, there is a tendency for the adhesive strength and cohesiveness of the adhesive layer to become better.

[0270] The content of acrylic resin in the adhesive composition is preferably 70-99% by mass, more preferably 80-98% by mass, and even more preferably 90-97% by mass, relative to the total amount (100% by mass) of the active ingredients in the adhesive composition.

[0271] [Cross-linking agent]

[0272] When the adhesive composition contains an adhesive resin having functional groups, it is preferable to further contain a crosslinking agent.

[0273] The crosslinking agent reacts with an adhesive resin containing functional groups, and the adhesive resins crosslink with each other using the functional group as the starting point for crosslinking.

[0274] Crosslinking agents can be used alone or in combination of two or more.

[0275] Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, and metal chelate crosslinking agents. Among these crosslinking agents, isocyanate crosslinking agents are preferred from the viewpoints of improving cohesion and adhesion, as well as ease of acquisition.

[0276] Examples of isocyanate crosslinking agents include: aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and phenyl dimethylene diisocyanate; alicyclic polyisocyanates such as dicyclohexylmethane-4,4'-diisocyanate, dicycloheptan triisocyanate, cyclopentane diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, methylene bis(cyclohexyl isocyanate), 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, and hydrogenated phenyl dimethylene diisocyanate; noncyclic aliphatic polyisocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; and other polyisocyanate compounds.

[0277] In addition, examples of isocyanate crosslinking agents include: trimethylolpropane addition-type modified polyisocyanate compounds, biuret-type modified polyisocyanates that react with water, and isocyanurate-type modified polyisocyanates containing isocyanurate rings.

[0278] Preferably, it is a trimethylolpropane addition-type modified polyisocyanate compound, more preferably a trimethylolpropane addition-type modified aromatic polyisocyanate compound, and even more preferably a trimethylolpropane addition-type modified toluene diisocyanate.

[0279] The content of the crosslinking agent in the adhesive composition can be appropriately adjusted according to the number of functional groups possessed by the adhesive resin. It is preferably 0.01 to 10 parts by weight, more preferably 0.03 to 7 parts by weight, and even more preferably 0.05 to 5 parts by weight relative to 100 parts by weight of the adhesive resin.

[0280] [Photopolymerization initiator]

[0281] The adhesive composition preferably further contains a photopolymerization initiator. By including a photopolymerization initiator in the energy-curable adhesive, there is a tendency for the energy-curing reaction to proceed sufficiently even using low-energy rays such as ultraviolet light.

[0282] Photopolymerization initiators can be used alone or in combination of two or more.

[0283] Examples of photopolymerization initiators include: 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, biacetyl, β-chloroanthraquinone, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide. Among these, 2,2-dimethoxy-2-phenylacetophenone is preferred.

[0284] The content of photopolymerization initiator in the adhesive composition is preferably 0.01 to 10 parts by mass relative to the total amount of adhesive resin (100 parts by mass), more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 3 parts by mass.

[0285] [Tackifier]

[0286] From the viewpoint of further improving adhesion, the adhesive composition may further contain tackifiers.

[0287] One type of tackifier can be used alone, or two or more types can be used in combination.

[0288] Examples of tackifiers include: rosin resins, terpene resins, styrene resins, pentene, isoprene, piperine (generated by the thermal decomposition of naphtha), C5 petroleum resins obtained by copolymerizing C5 fractions such as 1,3-pentadiene, indene (generated by the thermal decomposition of naphtha), C9 petroleum resins obtained by copolymerizing C9 fractions such as vinyltoluene, and hydrogenated resins obtained by hydrogenating these compounds.

[0289] When the adhesive composition contains a tackifier, the tackifier content is preferably 0.01 to 65% by mass, more preferably 0.1 to 50% by mass, and even more preferably 1 to 40% by mass, relative to the total amount (100% by mass) of the active ingredients in the adhesive composition.

[0290] [Energy-cured compounds]

[0291] For the purpose of adjusting the cohesiveness of the adhesive layer, the adhesive composition may further contain energy-curing compounds other than the above-mentioned components.

[0292] Energy-curing compounds can be used alone or in combination of two or more.

[0293] Examples of energy-curable compounds include monomers or oligomers that can be polymerized and cured by energy irradiation.

[0294] Examples of energy-curable compounds include: trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol (meth)acrylate, and other poly(meth)acrylate monomers; oligomers of urethane (meth)acrylates, polyester (meth)acrylates, polyether (meth)acrylates, epoxy (meth)acrylates, etc. From the viewpoint of curability, dipentaerythritol hexa(meth)acrylate is preferred, and more preferably dipentaerythritol hexaacrylate.

[0295] When the adhesive composition contains an energy-curable compound, the content of the energy-curable compound is not particularly limited, but is preferably 10 to 100 parts by weight, more preferably 20 to 70 parts by weight, and even more preferably 30 to 40 parts by weight relative to 100 parts by weight of the adhesive resin.

[0296] [Particles with thermal expansion]

[0297] When the adhesive layer is a thermally expandable layer containing thermally expandable particles, the adhesive layer can be formed using an adhesive composition containing thermally expandable particles. The preferred methods for the type and content of thermally expandable particles are the same as those for the type and content of thermally expandable particles described above in the description of thermally expandable layers.

[0298] [Additives for Adhesives]

[0299] In one aspect of the invention, without impairing the effects of the invention, in addition to the components described above, the adhesive composition may also contain adhesive additives generally used in adhesives.

[0300] Examples of such adhesive additives include: antioxidants, plasticizers, rust inhibitors, pigments, dyes, retarders, reaction promoters (catalysts), and ultraviolet absorbers.

[0301] It should be noted that these adhesive additives can be used individually or in combination of two or more.

[0302] When the adhesive composition contains these adhesive additives, the content of each adhesive 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 adhesive resin.

[0303] [Thickness of adhesive layer]

[0304] The thickness of the adhesive layer is preferably 1 to 80 μm, more preferably 2 to 60 μm, and even more preferably 3 to 40 μm. When the thickness of the adhesive layer is 1 μm or more, good adhesion can be obtained, and it tends to better protect the circuit surface of the semiconductor wafer (W) during processing. In addition, when the thickness of the adhesive layer is 80 μm or less, it tends to easily suppress the generation of tape debris when the adhesive sheet is cut.

[0305] (Manufacturing method of adhesive sheet for semiconductor processing)

[0306] The method for manufacturing the adhesive sheet according to one aspect of the present invention is not particularly limited and can be manufactured by known methods.

[0307] One aspect of the present invention is that the adhesive sheet for semiconductor processing can be manufactured, for example, by laminating an adhesive layer onto an intermediate layer after forming an intermediate layer on a substrate.

[0308] The substrate of the adhesive sheet of one aspect of the present invention can be a commercially available substrate or can be formed by known methods.

[0309] In the case of a substrate laminate consisting of a thermally expandable substrate and a non-thermally expandable substrate, the substrate laminate can be formed, for example, by coating one side of the non-thermally expandable substrate with the solvent-free resin composition used to form the thermally expandable substrate and then irradiating it with energy rays.

[0310] As a method for coating solvent-free resin compositions, known methods can be used, such as spin coating, spray coating, bar coating, doctor blade coating, roller coating, scraper coating, mold coating, gravure coating, etc.

[0311] As a method for forming an intermediate layer on a substrate, one example is a method in which the above-mentioned intermediate layer is coated onto the substrate with a composition and then cured by irradiation with energy rays.

[0312] As a method for coating an intermediate layer, the same method as the method for coating the above-mentioned solvent-free resin composition can be cited.

[0313] The energy rays can irradiate the composition for the intermediate layer only once, but from the viewpoint of easily controlling the curing degree of the intermediate layer, it is preferable to irradiate it multiple times.

[0314] When the energy radiation is ultraviolet light, the conditions for the first ultraviolet irradiation are: the ultraviolet irradiance is preferably 30–500 mW / cm². 2 More preferably, it is 50–340 mW / cm². 2 The preferred ultraviolet radiation dose is 100–2500 mJ / cm². 2 More preferably, it is 150–2000 mJ / cm². 2 .

[0315] The conditions for the second ultraviolet irradiation are: the ultraviolet irradiance is preferably 100–1000 mW / cm². 2 More preferably, it is 200–500 mW / cm 2 The preferred ultraviolet radiation dose is 300–5000 mJ / cm². 2 More preferably, it is 500–3000 mJ / cm². 2 The illuminance and irradiance of the second ultraviolet irradiation should preferably be greater than those of the first irradiation.

[0316] Irradiation with energy rays is preferably performed while the coated film is isolated from oxygen. One method for isolating the coated film from oxygen is, for example, attaching a release liner to the coated film.

[0317] As another method for forming an intermediate layer on a substrate, one example is to coat the intermediate layer composition described above onto the release surface of a release sheet, then irradiate it with energy rays to form the intermediate layer, and finally adhere the intermediate layer to one side of the substrate. The preferred methods for coating the intermediate layer composition and the irradiation conditions with energy rays are the same as described above.

[0318] Next, the adhesive layer is laminated onto the surface of the intermediate layer with the substrate. It should be noted that if a release liner is attached to the intermediate layer, the release liner should be peeled off.

[0319] One method for laminating an adhesive layer onto an intermediate layer is, for example, applying an adhesive composition directly to the surface of the intermediate layer and then drying it to form the adhesive layer.

[0320] Alternatively, as another method of laminating the adhesive layer onto the intermediate layer, it is possible to apply an adhesive composition to the release surface of the release sheet, dry it to form an adhesive layer, and then adhere the adhesive layer to the surface of the intermediate layer.

[0321] As a method for coating the adhesive composition, the same method as that for coating the intermediate layer composition can be cited. The drying conditions for the adhesive composition can be appropriately adjusted according to the type and content of the solvent in the adhesive composition.

[0322] As described above, a semiconductor processing adhesive sheet having a substrate, an intermediate layer, and an adhesive layer in sequence can be obtained. A method for manufacturing the semiconductor processing adhesive sheet according to one aspect of the present invention is described, in which a release liner is attached to the surface of the adhesive layer of the semiconductor processing adhesive sheet, and the release liner is removed.

[0323] [Semiconductor Device Manufacturing Method]

[0324] Next, after describing the processing object, namely the semiconductor wafer (W) having protrusions, in one aspect of the semiconductor device manufacturing method of the present invention, each step of the semiconductor device manufacturing method of one aspect of the present invention will be described in sequence.

[0325] <Semiconductor wafers (W)>

[0326] A semiconductor wafer (W) is formed by forming circuits, bumps, etc. on a substrate used for semiconductor wafers.

[0327] Examples of substrates used for semiconductor wafers include: silicon wafers; wafers made of gallium arsenide, silicon carbide, sapphire, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, etc.; and glass wafers.

[0328] The shape of a semiconductor wafer (W) when viewed from above is not particularly limited, and a disc-shaped wafer is usually used. The size of the disc-shaped semiconductor wafer (W) can be appropriately selected according to the equipment and manufacturing method used in each process, for example, sizes such as 8 inches (200 mm) in diameter and 12 inches (300 mm) in diameter can be given.

[0329] The thickness of the portion of the semiconductor wafer (W) excluding the protrusions is not particularly limited, but from the viewpoint of operability and processability of the semiconductor wafer (W), it is preferably 100 to 1000 μm, more preferably 200 to 900 μm, and even more preferably 300 to 800 μm.

[0330] The semiconductor wafer (W) has a protrusion on one side (Wα).

[0331] Examples of protrusions include circuits and bumps formed on the surface (Wα) of a semiconductor wafer (W). Preferably, the semiconductor wafer (W) has bumps.

[0332] Examples of bumps include those made of metals such as gold, silver, copper, nickel, tin, lead, and alloys containing these metals.

[0333] There are no particular limitations on the shape of the bump, for example, it can be spherical, cylindrical, elliptical cylindrical, ellipsoidal of revolution, conical, elliptical cone, cubic, cuboid, trapezoidal, etc.

[0334] There is no particular limit to the number of bumps formed on the semiconductor wafer (W), which can be changed appropriately according to design requirements.

[0335] The height of the protrusions on the semiconductor wafer (W) is not particularly limited, but from the viewpoint of significantly demonstrating the effect of the semiconductor device manufacturing method of one aspect of the present invention, it is preferably 10 to 500 μm, more preferably 15 to 400 μm, and even more preferably 20 to 300 μm.

[0336] exist Figure 2 In the figure, as an example of a semiconductor wafer (W), a schematic diagram of a semiconductor wafer W with bumps as protrusions (hereinafter also referred to as "bumped wafer W") is shown in top view.

[0337] A plurality of devices 6, divided by predetermined dividing lines 5, are formed on surface Wα of a bumped wafer W. Circuits (not shown) are formed on each device 6, such as... Figure 2 As shown in the enlarged view, multiple protrusions 7 are formed as protrusions.

[0338] The surface Wα of the bumped wafer W has a device region 8 with multiple devices 6 arranged between predetermined dividing lines 5, and a device non-forming region 9 that becomes the remaining part when monolithization.

[0339] Next, the various steps of a manufacturing method according to one aspect of the present invention will be described with reference to the accompanying drawings. It should be noted that, for ease of understanding of the features of the present invention, the parts that are the main parts used in the following description are shown enlarged or simplified for convenience. Therefore, the size ratios, quantities, etc., of each component may not be the same as in reality.

[0340] <Process 1>

[0341] Step 1 is a step of attaching a semiconductor processing adhesive sheet of one aspect of the present invention to the surface (Wα) of a semiconductor wafer (W) having a protrusion, with the adhesive layer as the adhesive surface.

[0342] Figure 3 (a) and (b) show cross-sectional views illustrating the process of attaching an adhesive sheet 10 of one aspect of the present invention to the surface Wα of a bumped wafer W.

[0343] Figure 3 (a) is equivalent to Figure 2The cross-sectional view of the bumped wafer W shown is shown in the figure. That is, the bumped wafer W has multiple devices 6 divided by a predetermined dividing line 5, multiple bumps 7 formed on each device 6, device regions 8, and device non-forming regions 9 on the surface Wα.

[0344] exist Figure 3 (b) shows the state in which the adhesive sheet 10 is attached to surface Wα of the bumped wafer W. It should be noted that the illustrations of the individual layers of the adhesive sheet 10 are omitted. The adhesive sheet 10 is attached to surface Wα with the adhesive layer as the bonding surface, and the surface opposite to the bonding surface is the substrate side surface Sα. The adhesive sheet 10 can be any semiconductor processing adhesive sheet used in the semiconductor device manufacturing method of one aspect of the present invention, such as the adhesive sheet 10a described above.

[0345] like Figure 3 As shown in (b), a protrusion 11 caused by the bump 7 and a non-protrusion 12 other than the protrusion 11 are formed on the substrate side surface Sα of the adhesive sheet 10 attached to the bumped wafer W. Figure 3 In method (b), the adhesive sheet 10 covers... Figure 3 (a) The area of ​​device region 8 shown in the diagram becomes a protrusion 11, covering Figure 3 (a) The portion of the device that does not form region 9 becomes non-convex portion 12.

[0346] In step 1, there is no particular limitation on the method of pasting the adhesive sheet. For example, existing known methods such as using a laminator can be applied.

[0347] <Process 2>

[0348] Step 2 is the following step: On the surface (Sα) of the substrate side of the above-mentioned adhesive sheet for semiconductor processing after the above-mentioned bonding, a cooling material is brought into contact with the upper surface of the above-mentioned protrusion, which is generated by the above-mentioned protrusion, and the above-mentioned non-protrusion is the part other than the protrusion.

[0349] (Cooling material)

[0350] The cooling material used in step 2 contacts the upper surface of the protrusion produced on the substrate side (Sα) of the adhesive sheet. This is done to suppress the thermal expansion of the adhesive sheet with the protrusion by means of its cooling effect during the heating in step 3.

[0351] The material of the cooling material is not particularly limited as long as it has a cooling effect, but a heat conductor is preferred. When the cooling material is a heat conductor, the cooling effect of the part with the protrusion is obtained by heat transfer to the heat conductor generated from the upper surface of the protrusion in contact with the heat conductor.

[0352] To improve the cooling effect, the heat conductor used as a cooling material may have an artificial cooling device that allows refrigerant to circulate internally. However, from an economic and production point of view, it may not need to have an artificial cooling device. That is, the heat conductor itself may not be intentionally cooled. In this case, the cooling effect can be achieved by naturally dissipating heat from the portion in contact with the upper surface of the protrusion of the adhesive sheet through the surface of the heat conductor itself.

[0353] As a heat conductor, a metal is preferred. Examples of metals include elemental metals such as copper, silver, gold, iron, zinc, lead, tin, nickel, chromium, and aluminum; and alloys such as stainless steel and brass. Among these, copper and aluminum are preferred from the viewpoint of versatility and thermal conductivity, with copper being more preferred.

[0354] From the viewpoint of improving cooling effect, the thermal conductivity of the heat conductor at 20°C is preferably 50 W / m·K or higher, more preferably 100 W / m·K or higher, and even more preferably 200 W / m·K or higher. Furthermore, from the viewpoint of versatility, the thermal conductivity of the cooling material used as the heat conductor at 20°C can be 1000 W / m·K or lower, 700 W / m·K or lower, or 500 W / m·K or lower.

[0355] The cooling material preferably has a flat surface as the surface (Sα) that contacts the substrate side (hereinafter also referred to as "surface (Cα)").

[0356] When the cooling material has a flat surface (Cα), the shape and size of the flat surface are not particularly limited; for example, it can be set to be substantially the same as the shape and size of the upper surface of the protrusion. By setting the shape and size of the cooling material's surface (Cα) to be substantially the same as the shape and size of the upper surface of the protrusion, and aligning the shape of the surface (Cα) with the shape of the upper surface of the protrusion, it is easy to selectively suppress the thermal expansion of the adhesive sheet on the portion of the surface with the protrusion.

[0357] The shape and size of the surface (Cα) of the cooling material are not limited to the methods described above. For example, the area of ​​the surface (Cα) of the cooling material can be smaller than the area of ​​the upper surface of the protrusion. When the thermal conductivity of the cooling material is high, a larger area than the area of ​​the surface (Cα) in contact with the cooling material can easily achieve a cooling effect. Therefore, even if the surface (Cα) of the cooling material, which has an area smaller than the area of ​​the upper surface of the protrusion, is in contact with a portion of the upper surface of the protrusion, there is a tendency to suppress the thermal expansion of the adhesive sheet on the part of the surface with the protrusion.

[0358] On the other hand, to further improve the cooling effect of the cooling material, the area of ​​the surface (Cα) of the cooling material can be made larger than the area of ​​the upper surface of the convex part, so that it is in contact with the entire surface of the upper surface of the convex part. By increasing the area of ​​the surface (Cα) of the cooling material, the cooling effect of the convex part that is in contact with the surface (Cα) of the cooling material tends to be improved.

[0359] From the viewpoint of achieving sufficient cooling effect, the thickness of the cooling material is preferably 100 times or more, more preferably 500 times or more, and even more preferably 1000 times or more, the thickness of the thermal expansion layer. Furthermore, from the viewpoint of processability, the thickness of the cooling material can be less than 10,000 times, less than 6,000 times, or less than 3,000 times the thickness of the thermal expansion layer.

[0360] Figure 4 The diagram shows a cross-sectional view illustrating the process of making the cooling material 13 contact the surface Sα on the substrate side of the adhesive sheet 10, which produces a protrusion 11 and the upper surface of the protrusion 11 in the portion other than the protrusion, i.e., the non-protrusion 12.

[0361] exist Figure 4 In the process, the cooling material 13 is in contact with the entire surface of the upper surface of the protrusion 11, and the size of the surface Cα of the cooling material 13 that is in contact with the surface Sα of the substrate side is basically the same as the size of the upper surface of the protrusion 11.

[0362] <Process 3>

[0363] Step 3 involves heating the semiconductor wafer (W) with the protrusions to above the expansion start temperature (t) of the thermally expanding particles while it is in contact with the cooling material. This heats the semiconductor processing adhesive sheet from the semiconductor wafer (W) side with the protrusions, and through the cooling effect of the cooling material, suppresses the expansion of the portion of the semiconductor processing adhesive sheet with the protrusions as its surface, and causes the portion with the non-protrusions as its surface to expand, thereby reducing the height difference between the protrusions and the non-protrusions.

[0364] In step 3, the adhesive sheet attached to the semiconductor wafer (W) is heated from the semiconductor wafer (W) side by heating the semiconductor wafer (W) to above the expansion start temperature (t) of the thermally expandable particles.

[0365] As a method for heating a semiconductor wafer (W), for example, it can be a method of heating the side (Wβ) of the semiconductor wafer (W) opposite to the aforementioned side (Wα). If a portion of the aforementioned side (Wα) is exposed, the exposed side (Wα) can be heated. By heating a portion of the semiconductor wafer (W) which has excellent thermal conductivity, the entire semiconductor wafer (W) can also be heated by heat transfer.

[0366] From the viewpoint of easily controlling the heating part and the heating temperature, the method of heating the semiconductor wafer (W) is preferably a method of contacting the semiconductor wafer (W) with a heated heat conductor, and more preferably a method of contacting the surface (Wβ) of the semiconductor wafer (W) with a heated heat conductor.

[0367] From the viewpoint of uniform heating, the method of contacting the heated heat conductor with the semiconductor wafer (W) is preferably a method of contacting the semiconductor wafer (W) with a heat conductor having a smooth surface, and more preferably a method of contacting a heating plate. Examples of heating plates include metal plates and ceramic plates.

[0368] The surface temperature of the heated heat conductor in contact with the semiconductor wafer (W) is at or above the expansion start temperature (t) of the thermally expanding particles, preferably "a temperature higher than the expansion start temperature (t)," more preferably "expansion start temperature (t) + 2°C" or higher, even more preferably "expansion start temperature (t) + 4°C" or higher, and even more preferably "expansion start temperature (t) + 5°C" or higher. Furthermore, from the viewpoint of energy efficiency and suppressing thermal changes in the semiconductor wafer (W) during heat stripping, the surface temperature of the heated heat conductor is preferably "expansion start temperature (t) + 50°C" or lower, more preferably "expansion start temperature (t) + 40°C" or lower, and even more preferably "expansion start temperature (t) + 30°C" or lower.

[0369] Furthermore, regarding the surface temperature of the heated heat conductor in contact with the semiconductor wafer (W), from the viewpoint of suppressing thermal changes in the semiconductor wafer (W), it is preferably 130°C or less, more preferably 120°C or less, and even more preferably 115°C or less, in the range above the expansion start temperature (t).

[0370] Figure 5 (a) and (b) show a process in which the surface Wβ of the bumped wafer W opposite to surface Wα is heated to above the expansion start temperature (t) of the thermally expandable particles while the cooling material 13 is in contact with the upper surface of the bump 11.

[0371] like Figure 5As shown in (a), the adhesive sheet 10 is heated by bringing the heating plate 14 into contact with the surface Wβ of the bumped wafer W. At this time, for the portion of the adhesive sheet 10 with a protrusion 11 on its surface that contacts the cooling material 13, thermal expansion is suppressed by the cooling effect of the cooling material 13. On the other hand, for the portion of the adhesive sheet 10 with a non-protrusion 12 on its surface that does not contact the cooling material 13, the cooling effect of the superior cooling material 13 is not easily achieved, and thermal expansion occurs.

[0372] The result is, as Figure 5 As shown in (b). Figure 5 In (a), the non-convex portion 12 has expanded, and the height of the expanded portion 12' is close to... Figure 5 (a) The height of part 11' of the protrusion 11 is reduced, the height difference between the protrusion 11 and the non-protrusion 12 is reduced, and the surface Sα on the substrate side is flattened.

[0373] The amount of expansion of the portion with non-protrusions 12 on the surface in step 3 can be adjusted, for example, by the content of thermally expandable particles in the thermally expandable layer. That is, if the height difference between the protrusions and non-protrusions is large before step 3, the expansion amount can be increased simply by increasing the content of thermally expandable particles in the thermally expandable layer. Conversely, if the height difference between the protrusions and non-protrusions is small before step 3, the expansion amount can be reduced simply by decreasing the content of thermally expandable particles in the thermally expandable layer.

[0374] <Process 4>

[0375] Step 4 is a process in which the semiconductor wafer (W) having the above-mentioned protrusions is processed while the substrate of the above-mentioned semiconductor processing adhesive sheet is fixed.

[0376] Examples of processing performed in step 4 include back-side grinding of a semiconductor wafer (W) with protrusions and monolithization of a semiconductor wafer (W) with protrusions. In one embodiment of the semiconductor device manufacturing method of the present invention, the preferred processing is back-side grinding of a semiconductor wafer (W) with protrusions, and more preferably, back-side grinding of a semiconductor wafer with bumps as protrusions.

[0377] Figure 6 The diagram shows a cross-sectional view illustrating the process of thinning a bumped wafer W while the substrate-side surface Sα of the adhesive sheet 10 is fixed.

[0378] exist Figure 6In this process, the substrate-side surface Sα of the adhesive sheet 10 is fixed to a support device 15 such as a chuck table, and the back surface Wβ of the bumped wafer W is ground to the desired thickness by a grinding machine 16. Because the substrate-side surface Sα of the adhesive sheet 10 has excellent flatness, uniform pressing pressure can be applied to the entire back surface of the semiconductor wafer, thereby thinning the semiconductor wafer W to a uniform thickness.

[0379] <Stripping Process>

[0380] After processing is performed in step 4, a stripping process can be performed to peel off the semiconductor processing adhesive sheet from the processed semiconductor wafer (W).

[0381] In cases where the adhesive layer of the adhesive sheet is formed by an energy-curable adhesive, the adhesive is cured by irradiating it with energy rays, reducing the peel force of the adhesive layer, and then the adhesive sheet is peeled off.

[0382] [Semiconductor wafer with bonding pad for semiconductor processing]

[0383] One aspect of the present invention is a semiconductor wafer with a semiconductor processing adhesive sheet, which is formed by attaching the semiconductor processing adhesive sheet, which sequentially comprises a substrate, an intermediate layer, and an adhesive layer, to the surface (Wa) of a semiconductor wafer (W) having protrusions, with the adhesive layer as the adhesive surface.

[0384] The aforementioned semiconductor processing adhesive sheet, when viewed from above, has the following characteristics:

[0385] Regions with or without gaps (a) and

[0386] Region (b) has a higher volumetric porosity than region (a) and a greater thickness than region (a).

[0387] The surface (Sα) on the substrate side is planarized by the difference in thickness between the aforementioned region (a) and the aforementioned region (b).

[0388] According to one aspect of the present invention, a semiconductor wafer with a semiconductor processing adhesive sheet is equivalent to a semiconductor wafer with a semiconductor processing adhesive sheet in which foamed thermally expandable particles are used as thermally expandable particles in the manufacturing method of a semiconductor device according to one aspect of the present invention, and the height difference between the protrusions and non-protrusions of the semiconductor processing adhesive sheet is reduced through the above-described steps 1 to 3. Therefore, a semiconductor wafer with a semiconductor processing adhesive sheet according to one aspect of the present invention can be manufactured by the above-described steps 1 to 3.

[0389] That is, the region (a) containing or not containing voids refers to the region that forms a protrusion in the semiconductor processing adhesive sheet bonded to the semiconductor wafer (W) when viewed from above. Regarding this protrusion, in step 3 of the semiconductor device manufacturing method according to one aspect of the present invention, the expansion of thermally expanding particles in the semiconductor processing adhesive sheet is suppressed by the cooling effect of the cooling material. Therefore, region (a) does not contain voids, or even if it does contain voids, its volume content is smaller than that of region (b).

[0390] Furthermore, region (b) refers to the region that is a non-protruding portion in the semiconductor processing adhesive sheet of one embodiment of the present invention, which is attached to the semiconductor wafer (W) when viewed from above. Regarding this non-protruding portion, in step 3 of the semiconductor device manufacturing method of one embodiment of the present invention, since the cooling effect of the cooling material is difficult to achieve, the thermally expandable particles in the semiconductor processing adhesive sheet expand due to heating, resulting in a higher void volume content than in region (a).

[0391] Thus, in a semiconductor wafer with a semiconductor processing adhesive sheet according to one aspect of the present invention, region (b) contains more voids than region (a). Moreover, due to the presence of voids, region (b) is thicker than region (a), and therefore, the surface (Sα) on the substrate side is planarized by the difference in thickness between region (a) and region (b).

[0392] Example

[0393] The present invention will be specifically described through the following embodiments, but the present invention is not limited to the following embodiments. It should be noted that the physical property values ​​in each embodiment are values ​​measured by the following methods.

[0394] [Weight-average molecular weight (Mw)]

[0395] The determination was performed using a gel permeation chromatography apparatus (manufactured by Tosoh Corporation, product name "HLC-8020") under the following conditions, and the values ​​were converted to standard polystyrene.

[0396] (Measurement conditions)

[0397] • Column: Consists of “TSK guard column HXL-L”, “TSK gel G2500HXL”, “TSK gel G2000HXL”, and “TSK gel G1000HXL” (all manufactured by Tosoh Corporation) connected in sequence.

[0398] Column temperature: 40℃

[0399] • Elution solvent: tetrahydrofuran

[0400] • Flow rate: 1.0 mL / min

[0401] [Thickness of each layer]

[0402] The measurement was performed at 23°C using a constant pressure thickness gauge (model: "PG-02J", based on standard specifications: JISK6783, Z1702, Z1709) manufactured by Teclock.

[0403] Average particle size (D) of thermally expandable particles 50 ), 90% particle size (D 90 )]

[0404] The particle distribution of thermally expandable particles before expansion at 23°C was measured using a laser diffraction particle size distribution measuring device (e.g., Malvern Mastersizer 3000). The particle sizes at which the cumulative volume frequencies, calculated starting from the side with the smallest particle size, correspond to 50% and 90% of the particle size, were then defined as the "average particle size (Dmin) of the thermally expandable particles." 50 ")" and "90% particle size of thermally expandable particles (D 90 )".

[0405] [Thickness accuracy of silicon wafers after backside grinding]

[0406] Regarding the thickness accuracy of silicon wafers after back-side grinding, a thickness measuring device (Hamamatsu Photonics, trade name "C8870") was used to measure the thickness of the entire surface of the silicon wafer at a measurement interval of 5 mm. The difference between the maximum and minimum thickness was calculated in the form of TTV (Total Thickness Variation) and evaluated.

[0407] Manufacturing of adhesive sheets for semiconductor processing

[0408] Manufacturing Examples 1-3

[0409] [Manufacturing of bonding sheets 1-3 for semiconductor processing]

[0410] Semiconductor processing adhesive sheets 1 to 3 were manufactured using the method shown below.

[0411] It should be noted that in the following description, the description of the copolymer composition, such as "X / Y / Z=A / B / C", indicates that the copolymer is a copolymer of monomer X, monomer Y and monomer Z, and is obtained by copolymerizing A parts by mass of monomer X, B parts by mass of monomer Y and C parts by mass of monomer Z.

[0412] (Preparation of the composition for the intermediate layer)

[0413] The intermediate layer, composed of 65 parts by mass of urethane acrylate oligomer (Arkema, trade name "CN9021 NS"), 25 parts by mass of isobornyl acrylate, 10 parts by mass of dodecyl acrylate, 3.4 parts by mass of photopolymerization initiator (IGMResins BV, trade name "Omnirad 1173", 2-hydroxy-2-methyl-1-phenylpropane-1-one), and 1.0 part by mass of chain transfer agent (Showa Denko, trade name "Karenz MT PE1", pentaerythritol tetra(3-mercaptobutyrate)), in the amounts listed in Table 1, exhibits the following thermally expandable particles (Nouryon, product name "Expancel (registered trademark) 031-40" (DU type), expansion start temperature (t) = 88°C, and average particle size (D). 50 =12.6μm, 90% particle size (D) 90 ( )=26.2μm), and a composition for use as an intermediate layer of a solvent-free resin composition was obtained.

[0414] (Fabrication of a substrate with an intermediate layer)

[0415] The intermediate layer composition obtained above is applied to a PET film (manufactured by Toyobo Co., Ltd., trade name "COSMOSHINE A4160", thickness 50μm) as a substrate by a doctor blade, so that the thickness of the intermediate layer reaches 100μm, thus forming an intermediate layer composition layer.

[0416] Next, a PET release film (manufactured by Lintec Corporation, trade name "SP-PET381130", thickness 38μm) is laminated onto the exposed surface of the composite layer in the formed intermediate layer to isolate the intermediate layer from oxygen. Then, a high-pressure mercury lamp is used at an illuminance of 80mW / cm². 2 Irradiation dose 200mJ / cm 2 After the first ultraviolet irradiation under certain conditions, a high-pressure mercury lamp was used at an illuminance of 330 mW / cm². 2 Irradiation dose 1260 mJ / cm 2 Under certain conditions, a second ultraviolet irradiation was performed, thereby curing the intermediate layer with the composition layer, and a substrate with an intermediate layer and a release sheet was produced.

[0417] (Preparation of the adhesive composition)

[0418] A polymer obtained by reacting 100 parts by weight of an acrylic copolymer (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., with 2-ethylhexyl acrylate (2EHA) / ethyl acrylate (EA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) = 60 / 15 / 5 / 20 (mass ratio)) with 2-methacryloyloxyethyl isocyanate (MOI) in a manner that adds 60 mol% of the hydroxyl groups of all the hydroxyl groups of the acrylic copolymer, with a weight average molecular weight (Mw) of 800,000; 1.1 parts by weight of trimethylolpropane-added toluene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate L") as a crosslinking agent; and 2,2-dimethoxy-2-phenylacetophenone (IGMResins) as a photopolymerization initiator. A binder composition was prepared by adding 2.2 parts by weight of toluene to adjust the concentration of solid components to 30% by weight, and stirring for 30 minutes.

[0419] (Preparation of the adhesive layer with release film)

[0420] Next, the prepared adhesive composition was coated onto a PET release film (manufactured by Lintec Corporation, trade name "SP-PET381130", thickness 38 μm), and dried to form an adhesive layer with a thickness of 10 μm on the release film, thus obtaining an adhesive layer with a release film.

[0421] (Fabrication of adhesive sheets for semiconductor processing)

[0422] The release film of the substrate with the intermediate layer obtained above is removed, and the adhesive layer with the release film obtained above is attached to the surface of the exposed intermediate layer, thereby obtaining semiconductor processing adhesive sheets 1 to 3 having a substrate, an intermediate layer, an adhesive layer and a release sheet in sequence.

[0423] Manufacturing Example 4

[0424] [Manufacturing of bonding sheet 4 for semiconductor processing]

[0425] In Manufacturing Example 1, the same as in Manufacturing Example 1, an adhesive sheet 4 for semiconductor processing was obtained except that thermally expandable particles were not incorporated into the composition for the intermediate layer.

[0426] [Semiconductor device manufacturing]

[0427] Next, a semiconductor device was manufactured using the semiconductor processing adhesive sheet prepared above.

[0428] It should be noted that in the following embodiments and comparative examples, in order to easily grasp the effects of the present invention, the protrusions of the silicon wafer are formed using an adhesive sheet with a PET substrate, and an excessively large protrusion is intentionally formed relative to the semiconductor processing adhesive sheet to be bonded. Therefore, the amount of reduction in the height difference between the protrusions and non-protrusions based on the manufacturing method of the present invention can be easily grasped.

[0429] Examples 1-3, Comparative Example 1

[0430] (1. Formation of the protrusion)

[0431] A 60mm diameter, PET-backed adhesive sheet (125μm thick) is glued to the center of one side of a circular silicon wafer (200mm in diameter, 740μm thick) as a protrusion. This creates a 125μm high protrusion in the center of the silicon wafer.

[0432] (2. Fabrication of a silicon wafer with a semiconductor processing adhesive sheet)

[0433] Next, the release film is removed from the semiconductor processing adhesive sheet obtained in each manufacturing example, and the exposed adhesive layer is used as the bonding surface. Using a BG tape laminator (manufactured by Lintec Corporation, product name "RAD 3510F / 12"), the worktable is heated to 65°C, and the adhesive layer is bonded to the entire surface of the side of the silicon wafer on which the protrusion is formed at a lamination speed of 5 mm / sec and a lamination pressure of 0.3 MPa.

[0434] Through the above process, a silicon wafer with a semiconductor processing adhesive sheet is obtained before thermal expansion, formed by a silicon wafer with a protrusion formed on one surface and a semiconductor processing adhesive sheet, wherein the semiconductor processing adhesive sheet is adhered to the entire surface of the silicon wafer on the side with the protrusion formed.

[0435] It should be noted that, in the following, when viewing a silicon wafer with a bonding sheet for semiconductor processing from above, the area containing the protrusion is sometimes referred to as the "protrusion forming area", and the area not containing the protrusion is referred to as the "non-protrusion forming area".

[0436] In addition, the silicon wafer with a semiconductor processing adhesive sheet before thermal expansion is referred to as "wafer with adhesive sheet (1)".

[0437] (3. Thickness measurement of wafer (1) with adhesive sheet)

[0438] Next, the silicon wafer side surface of the wafer (1) with the adhesive sheet was placed on a flat surface, and the substrate side surface was configured to be the contact surface of the constant pressure thickness gauge. The thickness of the protrusion-forming region and the non-protrusion-forming region was measured at four points respectively. It should be noted that for the protrusion-forming region, the thickness measurement points were set at four points equally spaced on a circle concentric with the protrusion-forming region and with a diameter of about 1 / 2 of the protrusion-forming region. For the non-protrusion-forming region, the thickness measurement points were set at four points equally spaced on a circle concentric with the non-protrusion-forming region and with a diameter of about 2 / 3 of the non-protrusion-forming region. Table 1 shows the average thickness of the protrusion-forming region and the average thickness of the non-protrusion-forming region in the wafer (1) with the adhesive sheet. As shown in Table 1, the thickness of the protrusion-forming region is greater than the thickness of the non-protrusion-forming region, and a protrusion is formed on the substrate side surface of the adhesive sheet.

[0439] (4. Heat expansion treatment of adhesive sheet)

[0440] Next, the wafer (1) with the adhesive sheet is placed on a flat surface with the substrate side surface as the top side, and a cylindrical copper (60 mm in diameter and 200 mm in thickness) used as a cooling material is stacked on the wafer (1) with the adhesive sheet in such a way that its bottom surface is aligned with the area formed by the protrusions in the substrate side surface.

[0441] Next, a wafer (1) with copper-coated adhesive sheets was placed on a heating plate with the silicon wafer side in contact with the heating plate and the substrate side with the copper adhesive sheets not in contact with the heating plate. It was heated for 2 minutes at 110°C, above the expansion start temperature of thermally expanding particles. Then, the wafer was left to stand in a standard environment (23°C, 50% RH) for 60 minutes as a wafer with adhesive sheets after thermal expansion. Hereinafter, the wafer with adhesive sheets after thermal expansion will be referred to as "wafer with adhesive sheets (2)".

[0442] (5. Thickness measurement of wafer (2) with adhesive sheet)

[0443] Next, the thickness of the wafer (2) with the adhesive sheet was measured using the same method as described in "3. Thickness Measurement of the Wafer (1) with Adhesive Sheet". Table 1 shows the average thickness of the protrusion forming region and the average thickness of the non-protrusion forming region in the wafer (2) with the adhesive sheet.

[0444] [Table 1]

[0445]

[0446] ※The thickness of each layer is the average value.

[0447] As shown in Table 1, in Examples 1-3, the thickness difference [(B)-(A)] of the wafer (2) with adhesive sheet after heat expansion treatment is less than the thickness difference [(B)-(A)] of the wafer (1) with adhesive sheet before heat expansion treatment. Furthermore, in Examples 1-3, since the reduced thickness difference varies depending on the content of thermally expandable particles, the protrusion of the adhesive sheet can be flattened by adjusting the content of thermally expandable particles accordingly to the height of the protrusion.

[0448] (6. Backside grinding of silicon wafers)

[0449] Next, the substrate side surface of the wafer (2) with adhesive sheet obtained in Example 3 and Comparative Example 1 was fixed using a chuck stage, and the back side of the silicon wafer was ground to a given thickness using a grinder.

[0450] However, in Comparative Example 1, the back-side grinding was stopped midway because the silicon wafer broke due to excessive protrusions on the substrate side surface during back-side grinding. After the back-side grinding was completed, the TTV of the back-side-ground silicon wafer was measured using the method described above. The result showed that the TTV of the silicon wafer in Example 3 was reduced by about 50% or more compared to the TTV of the silicon wafer in Comparative Example 1.

Claims

1. A method for manufacturing a semiconductor device, comprising using a semiconductor processing adhesive sheet, the semiconductor processing adhesive sheet having sequentially comprising a substrate, an intermediate layer, and an adhesive layer, wherein one or more layers selected from the substrate, the intermediate layer, and the adhesive layer are thermally expandable layers containing thermally expandable particles, the method for manufacturing the semiconductor device comprising the following steps 1 to 4. Step 1: A step of attaching the semiconductor processing adhesive sheet to the surface (Wα) of a semiconductor wafer (W) having a protrusion, with the adhesive layer as the adhesive surface; Step 2: On the substrate side surface (Sα) of the pasted semiconductor processing adhesive sheet, a cooling material is brought into contact with the upper surface of the protrusion in both the protrusion and non-protrusion portions, wherein the protrusion is generated by the protrusion and the non-protrusion is the portion other than the protrusion. Step 3: While in contact with the cooling material, the semiconductor wafer (W) with protrusions is heated to above the expansion start temperature (t) of the thermally expanding particles. Thus, the semiconductor processing adhesive sheet is heated from the semiconductor wafer (W) side with protrusions. Through the cooling effect of the cooling material, the expansion of the portion of the semiconductor processing adhesive sheet with the protrusions as its surface is suppressed, while the portion with the non-protrusions as its surface is expanded, thereby reducing the height difference between the protrusions and the non-protrusions. Step 4: A step of processing the semiconductor wafer (W) with protrusions while the substrate of the semiconductor processing adhesive sheet is fixed.

2. The method for manufacturing a semiconductor device according to claim 1, wherein, The thermal conductivity of the cooling material at 20°C is above 50 W / m·K.

3. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The cooling material is metal.

4. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The thickness of the cooling material is more than 100 times the thickness of the thermal expansion layer.

5. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The thickness of the intermediate layer is 10–500 μm.

6. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The thickness of the adhesive layer is 1–80 μm.

7. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The content of the thermally expandable particles is 0.05 to 25% by mass relative to the total mass (100% by mass) of the thermally expandable layer.

8. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The expansion initiation temperature (t) of the thermally expandable particles is above 50°C and below 125°C.

9. The method for manufacturing a semiconductor device according to claim 1 or 2, wherein, The intermediate layer is the thermal expansion layer.

10. The method of manufacturing a semiconductor device according to claim 1 or 2, wherein, The heating of the semiconductor wafer (W) with protrusions in step 3 is performed by heating the side (Wβ) of the semiconductor wafer (W) opposite to the side (Wα).

11. The method of manufacturing a semiconductor device according to claim 1 or 2, wherein, The height of the protrusion is 10–500 μm.

12. The method of manufacturing a semiconductor device according to claim 1 or 2, wherein, The semiconductor wafer (W) with protrusions is a semiconductor wafer with bumps as the protrusions.

13. The method of manufacturing a semiconductor device according to claim 12, wherein, The processing in step 4 is back-side grinding of the semiconductor wafer with the bumps.

14. A semiconductor wafer with a semiconductor processing adhesive sheet, wherein the semiconductor processing adhesive sheet, which sequentially comprises a substrate, an intermediate layer, and an adhesive layer, is bonded to the surface (Wa) of a semiconductor wafer (W) having a protrusion, with the adhesive layer as the bonding surface, wherein, The semiconductor processing adhesive sheet, when viewed from above, has the following characteristics: Regions with or without gaps (a) and Region (b) has a higher volumetric porosity than region (a) and a greater thickness than region (a). The surface (Sα) on the substrate side is planarized by the thickness difference between region (a) and region (b).

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