WO2020189568A1

WO2020189568A1 - Adhesive sheet and semiconductor device production method

Info

Publication number: WO2020189568A1
Application number: PCT/JP2020/011177
Authority: WO
Inventors: 康彦垣内; 高志阿久津; 慎弥高岡
Original assignee: リンテック株式会社
Priority date: 2019-03-15
Filing date: 2020-03-13
Publication date: 2020-09-24
Also published as: JPWO2020189568A1; TW202045657A; CN113613893A; CN113613893B; KR20210141929A

Abstract

The invention addresses the problem of providing an adhesive sheet allowing a temporarily fixed adherend to be released readily by heating while suppressing surface contamination on the adherend surface after release, and providing a semiconductor device production method using the adhesive sheet. The adhesive sheet has a layered structure wherein an adhesive layer (X1), a thermally expanding base material layer (Y1) containing thermally expanding particles, and a non-thermally expanding base material layer (Y2), are disposed in this order. The Young's modulus of the adhesive layer (X1) at 23°C is 5.0 MPa or greater. The Young's modulus of the non-thermally expanding base material layer (Y2) at 23°C is higher than the Young's modulus of the adhesive layer (X1) at 23°C.

Description

Manufacturing method of adhesive sheet and semiconductor device

The present invention relates to an adhesive sheet and a method for manufacturing a semiconductor device using the adhesive sheet.

Adhesive sheets are not only used for semi-permanently fixing members, but also for processing and inspection of building materials, interior materials, electronic parts, etc. (hereinafter, "adhesion"). It may be used as a temporary fixing sheet for temporarily fixing (also called "body"). For example, in the manufacturing process of a semiconductor device, a temporary fixing sheet is used when processing a semiconductor wafer.

In the manufacturing process of a semiconductor device, a semiconductor wafer is processed into a semiconductor chip through a grinding process of reducing the thickness by grinding, an individualizing process of cutting and separating and individualizing. At this time, the semiconductor wafer is subjected to a predetermined process in a state of being temporarily fixed to the temporary fixing sheet. The semiconductor chips obtained by performing the predetermined processing are separated from the temporary fixing sheet, and then, if necessary, an expanding step of widening the distance between the semiconductor chips and a re-arrangement of a plurality of semiconductor chips having the widened distances. After an arrangement process, an inversion process for inverting the front and back of the semiconductor chip, and the like are appropriately performed, the semiconductor chip is mounted on the substrate. Also in each of the above steps, a temporary fixing sheet suitable for each application can be used.

Patent Document 1 discloses a heat-release type pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component, in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres is provided on at least one surface of a base material. .. According to the document, the heat-removable adhesive sheet can secure a contact area of a predetermined size with respect to the adherend when cutting an electronic component, and thus exhibits adhesiveness capable of preventing adhesive defects such as chip skipping. On the other hand, there is a description that it can be easily peeled off by reducing the contact area with the adherend by expanding the heat-expandable microspheres by heating after use.

Japanese Patent No. 3594853

However, when the pressure-sensitive adhesive layer contains the heat-expandable particles as in the pressure-sensitive adhesive sheet disclosed in Patent Document 1, the residue derived from the heat-expandable particles adheres to the surface of the adherend and heat. The surface of the adherend after being peeled off by heating due to the adhesion of some of the pressure-sensitive adhesive layers to the surface of the adherend due to the deformation and alteration of the pressure-sensitive adhesive layer due to the expansion of the expansive particles (so-called "glue residue"). Is concerned that it will be contaminated.

The present invention has been made in view of the above problems, and the temporarily fixed adherend can be easily peeled off by heating, and the contamination of the adherend surface after peeling can be suppressed. It is an object of the present invention to provide an adhesive sheet capable of being formed and a method for manufacturing a semiconductor device using the adhesive sheet.

The present inventors arranged the structure of the pressure-sensitive adhesive sheet in this order: (1) a pressure-sensitive adhesive layer, a heat-expandable base material layer containing heat-expandable particles, and a non-heat-expandable base material layer. Having a laminated structure, (2) adjusting the Young ratio of the pressure-sensitive adhesive layer to a specific range, and (3) the Young ratio of the pressure-sensitive adhesive layer and the Young ratio of the non-thermally expandable base material layer. We have found that the above problems can be solved by adjusting to a specific relationship, and have completed the present invention.

That is, the present invention relates to the following [1] to [15].
[1] A laminated structure in which a pressure-sensitive adhesive layer (X1), a heat-expandable base material layer (Y1) containing heat-expandable particles, and a non-heat-expandable base material layer (Y2) are arranged in this order. Have and
The Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is 5.0 MPa or less.
A pressure-sensitive adhesive sheet in which the Young's modulus of the non-thermally expandable base material layer (Y2) at 23 ° C. is higher than the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C.
[2] The pressure-sensitive adhesive sheet according to the above [1], wherein the pressure-sensitive adhesive layer (X1) has a thickness of 3 to 10 μm at 23 ° C.
[3] The product of the Young's modulus (unit: MPa) of the pressure-sensitive adhesive layer (X1) at 23 ° C. and the thickness (unit: μm) of the pressure-sensitive adhesive layer (X1) at 23 ° C. is 0.3 to The adhesive sheet according to the above [1] or [2], which is 50.
[4] Any of the above [1] to [3], wherein the pressure-sensitive adhesive layer (X1) is a layer formed from a pressure-sensitive adhesive composition (x-1) containing an acrylic resin and an isocyanate-based cross-linking agent. Adhesive sheet described in Crab.
[5] The pressure-sensitive adhesive sheet according to the above [4], wherein the isocyanate-based cross-linking agent contains an isocyanurate-type modified product having an isocyanurate ring.
[6] The pressure-sensitive adhesive sheet according to any one of [1] to [5] above, wherein the non-thermally expandable base material layer (Y2) has a Young's modulus of 700 MPa or more at 23 ° C.
[7] The pressure-sensitive adhesive sheet according to any one of [1] to [6] above, wherein the non-thermally expandable base material layer (Y2) is a polyethylene terephthalate film.
[8] The non-thermally expandable base material layer (Y2) further has an adhesive layer (X2) on a surface opposite to the laminated surface of the heat expandable base material layer (Y1). ] To [7].
[9] The pressure-sensitive adhesive sheet according to any one of [1] to [7] above, wherein the thermally expandable particles have an expansion start temperature (t) of 50 ° C. or higher and lower than 125 ° C.
[10] The pressure-sensitive adhesive sheet according to the above [8], wherein the thermally expandable particles have an expansion start temperature (t) of 50 ° C. or higher and lower than 125 ° C.
[11] The pressure-sensitive adhesive sheet according to the above [10], wherein the pressure-sensitive adhesive layer (X2) is a pressure-sensitive adhesive layer that is cured by irradiation with energy rays to reduce the adhesive strength.
[12] The object to be processed and inspected is attached to the adhesive sheet according to any one of [1] to [11] above.
A step of heating the pressure-sensitive adhesive sheet to a temperature equal to or higher than the expansion start temperature (t) of the heat-expandable particles contained in the pressure-sensitive adhesive sheet after applying one or more selected from processing and inspection to the processing inspection object. A method for manufacturing a semiconductor device, including.
[13] A method for manufacturing a semiconductor device, which comprises the following steps 1A to 3A, the following first separation step, and the following second separation step using the pressure-sensitive adhesive sheet according to the above [10] or [11].
Step 1A: A process of attaching the object to be processed to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet, and attaching a support to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet Step 2A: For the object to be processed Step 3A: A process of performing one or more treatments selected from a grinding process and an individualization process Step 3A: A thermocurable surface of the processed object to be processed, which is opposite to the pressure-sensitive adhesive layer (X2). First separation step: The pressure-sensitive adhesive sheet is heated to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C. to separate the pressure-sensitive adhesive layer (X1) from the support. Second separation step: Step of separating the pressure-sensitive adhesive layer (X2) from the object to be processed [14] Using the pressure-sensitive adhesive sheet according to the above [10] or [11], the following steps 1B to 3B, the following A method for manufacturing a semiconductor device including a first separation step and the following second separation step.
Step 1B: A process of attaching the object to be processed to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet, and attaching a support to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet Step 2B: For the object to be processed Step 3B: A process of performing one or more treatments selected from a grinding treatment and an individualizing treatment. The surface of the processed object to which the treatment has been subjected to the treatment is heat-curable on the surface opposite to the adhesive layer (X1). First separation step: The pressure-sensitive adhesive sheet is heated to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C., and the pressure-sensitive adhesive layer (X1) and the object to be processed are separated from each other. Separation step Second separation step: Step of separating the pressure-sensitive adhesive layer (X2) and the support [15] Using the pressure-sensitive adhesive sheet according to the above [11],
The method for manufacturing a semiconductor device according to the above [13] or [14], wherein the second separation step includes a step of curing the pressure-sensitive adhesive layer (X2) by irradiating the pressure-sensitive adhesive layer (X2) with energy rays. ..

The adhesive sheet of the present invention can easily peel off the temporarily fixed adherend by heating, and can suppress contamination of the surface of the adherend after peeling.

It is sectional drawing which shows an example of the structure of the pressure-sensitive adhesive sheet of this invention. It is sectional drawing which shows another example of the structure of the pressure-sensitive adhesive sheet of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention. It is sectional drawing explaining an example of the process of the manufacturing method of the semiconductor device of this invention.

In the present specification, the "active ingredient" refers to an ingredient contained in the target composition excluding the diluting solvent.
Further, in the present specification, the mass average molecular weight (Mw) is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method, and is specifically measured based on the method described in Examples. It is the value that was set.

In the present specification, for example, "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid", and other similar terms are also used.
Further, in the present specification, the lower limit value and the upper limit value described stepwise with respect to a preferable numerical range (for example, a range such as content) can be independently combined. For example, from the description of "preferably 10 to 90, more preferably 30 to 60", the "favorable lower limit value (10)" and the "more preferable upper limit value (60)" are combined to obtain "10 to 60". You can also do it.

In the present specification, the "energy beam" means an electromagnetic wave or a charged particle beam having an energy quantum, and examples thereof include ultraviolet rays, radiation, and electron beams. Ultraviolet rays can be irradiated by using, for example, an electrodeless lamp, a high-pressure mercury lamp, a metal halide lamp, a UV-LED, or the like as an ultraviolet source. The electron beam can be irradiated with an electron beam generated by an electron beam accelerator or the like.
As used herein, the term "energy ray polymerizable" means the property of polymerizing by irradiating with energy rays.

In the present specification, whether the "layer" is a "non-thermally expanding layer" or a "thermally expanding layer" is determined as follows.
When the layer to be judged contains the heat-expandable particles, the layer is heat-treated at the expansion start temperature (t) of the heat-expandable particles for 3 minutes. If the volume change rate calculated from the following formula is less than 5%, the layer is judged to be a "non-thermally expandable layer", and if it is 5% or more, the layer is a "thermally expandable layer". Judge that there is.
Volume change rate (%) = {(volume of the layer after heat treatment-volume of the layer before heat treatment) / volume of the layer before heat treatment} × 100
The layer containing no thermally expandable particles is referred to as a "non-thermally expandable layer".

In the present specification, the "front surface" of the semiconductor wafer and the semiconductor chip refers to the surface on which the circuit is formed (hereinafter, also referred to as the "circuit surface"), and the "back surface" of the semiconductor wafer and the semiconductor chip is the circuit formed. Refers to the surface that is not.

[Adhesive sheet]
In the pressure-sensitive adhesive sheet of the present invention, a pressure-sensitive adhesive layer (X1), a heat-expandable base material layer (Y1) containing heat-expandable particles, and a non-heat-expandable base material layer (Y2) are arranged in this order. The pressure-sensitive adhesive layer (X1) has a young ratio of 5.0 MPa or less at 23 ° C., and the non-thermally expandable base material layer (Y2) has a young ratio at 23 ° C. It is an adhesive sheet having a higher Young's ratio of the agent layer (X1) at 23 ° C.

In the pressure-sensitive adhesive sheet of the present invention, the heat-expandable particles contained in the heat-expandable base material layer (Y1) are heated to a temperature equal to or higher than the expansion start temperature (t) to expand, and the pressure-sensitive adhesive layer (X1) is adhered. By forming irregularities on the surface well, the contact area between the adherend attached to the adhesive surface of the adhesive layer (X1) and the adhesive surface is greatly reduced. As a result, the adherend can be easily peeled off from the adhesive sheet. Moreover, since the heat-expandable particles are contained in the heat-expandable base material layer (Y1), contamination of the adherend surface due to the heat-expandable particles is suppressed.
Here, in the pressure-sensitive adhesive sheet of the present invention, the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is adjusted to 5.0 MPa or less. Therefore, the pressure-sensitive adhesive layer (X1) firmly follows the unevenness of the surface of the heat-expandable base material layer (Y1) on the pressure-sensitive adhesive layer (X1) side caused by the expansion of the heat-expandable particles, and the pressure-sensitive adhesive layer (X1) Unevenness is well formed on the adhesive surface of X1).
On the other hand, when the Young ratio of the pressure-sensitive adhesive layer (X1) at 23 ° C. exceeds 5.0 MPa, the surface of the heat-expandable base material layer (Y1) on the pressure-sensitive adhesive layer (X1) side caused by the expansion of the heat-expandable particles. The pressure-sensitive adhesive layer (X1) cannot sufficiently follow the unevenness of the surface, and the surface unevenness on the pressure-sensitive adhesive layer (X1) side of the heat-expandable base material layer (Y1) is formed by the pressure-sensitive adhesive layer (X1). By at least one of being suppressed, unevenness is less likely to be formed on the adhesive surface of the adhesive layer (X1).
Further, since the coefficient of thermal expansion of the non-thermally expandable base material layer (Y2) at 23 ° C. is higher than the coefficient of thermal expansion of the pressure-sensitive adhesive layer (X1) at 23 ° C., it expands when the thermally expandable particles are expanded. Concavities and convexities are more likely to be formed on the surface of the heat-expandable base layer (Y1) on the pressure-sensitive adhesive layer (X1) side than on the surface of the sex-based base layer (Y1) on the non-expandable base layer (Y2) side. Therefore, unevenness is satisfactorily formed on the adhesive surface of the adhesive layer (X1).
When the Young ratio of the non-thermally expandable base material layer (Y2) at 23 ° C. is equal to or lower than the Young ratio of the pressure-sensitive adhesive layer (X1) at 23 ° C. Unevenness is less likely to be formed on the surface of the pressure-sensitive adhesive layer (X1) side of Y1), and unevenness is less likely to be formed on the adhesive surface of the pressure-sensitive adhesive layer (X1).

Here, the pressure-sensitive adhesive sheet of the present invention is heated to a temperature equal to or higher than the expansion start temperature (t) of the heat-expandable particles contained in the heat-expandable base material layer (Y1) so that the pressure-sensitive adhesive sheet and the adherend can be brought together. Adhesion can be significantly reduced. Therefore, when the pressure-sensitive adhesive sheet according to one aspect of the present invention is peeled off by heating, the pressure-sensitive adhesive sheet can be peeled off from the adherend without applying a force for peeling off the pressure-sensitive adhesive sheet. Specifically, in a laminated body in which an adhesive sheet is attached to an adherend, when the adhesive sheet is peeled off by heating, the adhesive sheet side is directed downward and the adhesive sheet is dropped from the adherend by gravity to peel off. Can be made to.
In the present specification, the state in which the adhesive sheet is peeled off from the adherend or peeled off without applying the force for peeling off the adhesive sheet is referred to as "self-peeling". Moreover, such a property is called "self-peeling property".

In the pressure-sensitive adhesive sheet of one aspect of the present invention, the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. enhances the followability of the pressure-sensitive adhesive layer (X1) to the deformation of the heat-expandable base material layer (Y1) and thermally expands. From the viewpoint of facilitating the formation of irregularities on the adhesive surface of the pressure-sensitive adhesive layer (X1) when the sex particles are expanded, it is preferably 4.5 MPa or less, more preferably 4.0 MPa or less, still more preferably 3.5 MPa or less. It is even more preferably 3.0 MPa or less, even more preferably 2.5 MPa or less, even more preferably 2.0 MPa or less, even more preferably 1.5 MPa or less, even more preferably 1.3 MPa or less. Moreover, it is usually 0.1 MPa or more.
In the present specification, the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is measured by the method described in Examples described later.

[Composition of adhesive sheet]
In the pressure-sensitive adhesive sheet of the present invention, a pressure-sensitive adhesive layer (X1), a heat-expandable base material layer (Y1) containing heat-expandable particles, and a non-heat-expandable base material layer (Y2) are arranged in this order. The pressure-sensitive adhesive sheet according to one aspect of the present invention may have a laminated structure, but the pressure-sensitive adhesive sheet (X1), the heat-expandable base material layer (Y1), and the non-heat-expandable base material layer (Y2) It may have only, or it may have other layers, if desired.
For example, when the pressure-sensitive adhesive sheet of one aspect of the present invention is used for one or more selected from processing and inspection of an adherend, a non-expandable base material layer is used from the viewpoint of improving the processability and inspectability of the adherend. It is preferable that the pressure-sensitive adhesive layer (X2) is further provided on the surface of (Y2) opposite to the laminated surface of the heat-expandable base material layer (Y1). By having this structure, the adherend is attached to one of the adhesive layers (X1) and the adhesive layer (X2), and the support is attached to the other adhesive layer. Can be done.
By fixing the adherend to the support via an adhesive sheet, vibration, misalignment, and adherence of the adherend when one or more selected from processing and inspection are applied to the adherend. It is possible to suppress damage and the like when the body is fragile, and improve the processing accuracy and processing speed as well as the inspection accuracy and inspection speed.
In the following description, unless otherwise specified, the "double-sided pressure-sensitive adhesive sheet" refers to a pressure-sensitive adhesive layer (X1), a heat-expandable base material layer (Y1) containing heat-expandable particles, and a non-heat-expandable group. It is assumed that the material layer (Y2) and the pressure-sensitive adhesive layer (X2) mean a pressure-sensitive adhesive sheet having a laminated structure arranged in this order.

The pressure-sensitive adhesive sheet according to one aspect of the present invention may have a release material on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer (X1). Further, when the pressure-sensitive adhesive sheet according to one aspect of the present invention has the structure of a double-sided pressure-sensitive adhesive sheet, it has a release material on the pressure-sensitive adhesive surface of at least one of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2). May be good.

Next, the configuration of the pressure-sensitive adhesive sheet according to one aspect of the present invention will be described more specifically with reference to the drawings.

The pressure-sensitive adhesive sheet according to one aspect of the present invention includes a pressure-sensitive adhesive layer (X1) as shown in FIG. An adhesive sheet 1a having a laminated structure in which the base material layer (Y2) is arranged in this order can be mentioned.
The pressure-sensitive adhesive sheet according to one aspect of the present invention may have a structure in which the release material 10 is further provided on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer (X1), as in the pressure-sensitive adhesive sheet 1b shown in FIG. 1 (b).

As another aspect of the pressure-sensitive adhesive sheet of the present invention, those having the structure of the double-sided pressure-sensitive adhesive sheet can be mentioned.
Examples of the pressure-sensitive adhesive sheet having such a structure include a pressure-sensitive adhesive layer (X1), a heat-expandable base material layer (Y1) containing heat-expandable particles, and non-heat as shown in FIG. Examples thereof include a pressure-sensitive adhesive sheet 2a having a laminated structure in which an expandable base material layer (Y2) and a pressure-sensitive adhesive layer (X2) are arranged in this order.
Further, as in the double-sided adhesive sheet 2b shown in FIG. 2B, the release material 10a is further provided on the adhesive surface of the adhesive layer (X1), and the release material is further provided on the adhesive surface of the adhesive layer (X2). It may be configured to have 10b.

In the double-sided pressure-sensitive adhesive sheet 2b shown in FIG. 2B, the peeling force when the release material 10a is peeled from the pressure-sensitive adhesive layer (X1) and the peeling force when the release material 10b is peeled off from the pressure-sensitive adhesive layer (X2). When both release materials are pulled outward and attempted to be peeled off, a phenomenon may occur in which the pressure-sensitive adhesive layer is divided and peeled off along with the two release materials. From the viewpoint of suppressing such a phenomenon, it is preferable to use two types of release materials designed so that the release forces from the pressure-sensitive adhesive layers attached to the two

release materials

10a and 10b are different from each other.

As yet another aspect of the pressure-sensitive adhesive sheet of the present invention, the double-sided pressure-sensitive adhesive sheet 2a shown in FIG. 2A is peeled off on both sides of the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2). A double-sided adhesive sheet having a structure in which the treated release material is laminated in a roll shape may be used.

The pressure-sensitive adhesive sheet according to one aspect of the present invention is between the pressure-sensitive adhesive layer (X1) and the heat-expandable base material layer (Y1), and between the heat-expandable base material layer (Y1) and the non-heat-expandable base material layer (Y2). It may or may not have another layer between at least one of the layers between and.
When the pressure-sensitive adhesive sheet according to one aspect of the present invention is the double-sided pressure-sensitive adhesive sheet, in addition to the above, a heat-expandable base material layer is provided between the pressure-sensitive adhesive layer (X1) and the heat-expandable base material layer (Y1). Another layer between at least one of the layers between (Y1) and the non-thermally expandable substrate layer (Y2) and between the non-thermally expandable substrate layer (Y2) and the pressure-sensitive adhesive layer (X2). It may or may not have another layer.
However, the pressure-sensitive adhesive sheet according to one aspect of the present invention has the viewpoint of transmitting the deformation of the heat-expandable base material layer (Y1) due to the expansion of the heat-expandable particles to the pressure-sensitive adhesive layer (X1) satisfactorily. ) And the heat-expandable base material layer (Y1) are preferably directly laminated.

Next, regarding the pressure-sensitive adhesive sheet of the present invention, after explaining the heat-expandable particles required for forming irregularities on the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer (X1) by heating, the pressure-sensitive adhesive layer (X1) and the heat-expanding The sex substrate layer (Y1), the non-thermally expandable substrate layer (Y2), and the pressure-sensitive adhesive layer (X2) will be described.

<Thermal expandable particles>
The thermally expandable particles used in the pressure-sensitive adhesive sheet of the present invention may be particles that expand by heating, and the expansion start temperature (t) is appropriately selected according to the use of the pressure-sensitive adhesive sheet.

By the way, in recent years, when a semiconductor chip is mounted on a substrate, the semiconductor chip is attached to the substrate via a thermosetting film-like adhesive called a die attach film (hereinafter, also referred to as "DAF"). The process is adopted.
The DAF is attached to one surface of the semiconductor wafer or a plurality of fragmented semiconductor chips, and is divided into the same shape as the semiconductor chip at the same time as the semiconductor wafer is fragmented or after being attached to the semiconductor chip. The semiconductor chip with DAF obtained by individualizing is attached (diatached) to the substrate from the DAF side, and then the semiconductor chip and the substrate are fixed by thermosetting the DAF. At this time, the DAF needs to retain the property of adhering by pressure sensitivity or heating until it is attached to the substrate. However, when the semiconductor chip with DAF is used as an adherend of a heat-release type adhesive sheet, the DAF is cured before the die attachment due to the heating when the thermally expandable particles are expanded, and the DAF with respect to the substrate is cured. Adhesive strength may decrease. It is desirable to suppress the decrease in the adhesive strength of the DAF because it causes a decrease in the bonding reliability between the semiconductor chip and the substrate. That is, it is desirable that the thermal change of the adherend is suppressed at the time of heat peeling.
From this point of view, in the pressure-sensitive adhesive sheet of one aspect of the present invention, the expansion start temperature (t) of the heat-expandable particles is preferably less than 125 ° C., more preferably 120 ° C. or lower, still more preferably 115 ° C. or lower, still more preferable. Is 110 ° C. or lower, more preferably 105 ° C. or lower.

Further, if a heat-release type adhesive sheet having a low expansion start temperature is used as the heat-expandable particles, the heat-expandable particles will expand due to a temperature rise such as when grinding the adherend. There is. Such unintended expansion of the heat-expandable particles leads to unintended separation and misalignment of the adherend, and is therefore desirable to be suppressed.
From this point of view, in the pressure-sensitive adhesive sheet of one aspect of the present invention, the expansion start temperature (t) of the heat-expandable particles is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, still more preferably 60 ° C. or higher, still more preferably. Is 70 ° C. or higher.
In addition, in this specification, the expansion start temperature (t) of a heat-expandable particle means a value measured based on the following method.

(Measurement method of expansion start temperature (t) of thermally expandable particles)
To an aluminum cup with a diameter of 6.0 mm (inner diameter 5.65 mm) and a depth of 4.8 mm, 0.5 mg of the heat-expandable particles to be measured are added, and an aluminum lid (diameter 5.6 mm, thickness 0. Prepare a sample on which 1 mm) is placed.
Using a dynamic viscoelasticity measuring device, the height of the sample is measured with a force of 0.01 N applied by a pressurizer from the upper part of the aluminum lid to the sample. Then, with a force of 0.01 N applied by the pressurizer, it is heated from 20 ° C. to 300 ° C. at a heating rate of 10 ° C./min, the amount of displacement of the pressurizer in the vertical direction is measured, and the displacement in the positive direction is measured. Let the displacement start temperature be the expansion start temperature (t).

The thermally expandable particles are microencapsulated foaming agents composed of an outer shell made of a thermoplastic resin and an contained component contained in the outer shell and vaporized when heated to a predetermined temperature. It is preferable to have.
Examples of the thermoplastic resin constituting the outer shell of the microencapsulating foaming agent include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethylmethacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone and the like.

Examples of the contained component which is a component contained in the outer shell of the microencapsulating foaming agent include propane, propylene, butene, n-butane, isopentane, isopentane, neopentane, n-pentane, n-hexane, isohexane, and n-. Examples thereof include low boiling point liquids such as heptane, n-octane, cyclopropane, cyclobutane and petroleum ether.
Among these, from the viewpoint of suppressing the thermal change of the adherend during heat peeling and suppressing the unintended expansion of the thermally expandable particles due to the temperature rise such as when grinding the adherend, heat is applied. When the expansion start temperature (t) of the expandable particles is 50 ° C. or higher and lower than 125 ° C., the inclusion components are preferably propane, isobutane, n-pentane, and cyclopropane.
One of these inclusion components may be used alone, or two or more thereof may be used in combination.
The expansion start temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of the inclusion component.

The average particle diameter of the heat-expandable particles used in one embodiment of the present invention before expansion at 23 ° C. is preferably 3 to 100 μm, more preferably 4 to 70 μm, still more preferably 6 to 60 μm, still more preferably 10 to 10. It is 50 μm.
The average particle size of the heat-expandable particles before expansion is the volume medium particle size (D ₅₀ ), and is a laser diffraction type particle size distribution measuring device (for example, manufactured by Malvern, product name “Mastersizer 3000”). In the particle distribution of the heat-expandable particles before expansion, the cumulative volume frequency calculated from the smaller particle size of the heat-expandable particles before expansion means the particle size corresponding to 50%.

The 90% particle diameter (D ₉₀ ) of the thermally expandable particles used in one embodiment of the present invention before expansion at 23 ° C. is preferably 10 to 150 μm, more preferably 15 to 100 μm, still more preferably 20 to 90 μm. Even more preferably, it is 25 to 80 μm.
The 90% particle size (D ₉₀ ) of the thermally expandable particles before expansion is the expansion measured using a laser diffraction type particle size distribution measuring device (for example, manufactured by Malvern, product name "Mastersizer 3000"). In the particle distribution of the previous heat-expandable particles, it means the particle size in which the cumulative volume frequency calculated from the smaller particle size of the heat-expandable particles before expansion corresponds to 90%.

The maximum volume expansion rate when the thermally expandable particles used in one embodiment of the present invention are heated to a temperature equal to or higher than the expansion start temperature (t) is preferably 1.5 to 200 times, more preferably 2 to 150 times, and further. It is preferably 2.5 to 120 times, and even more preferably 3 to 100 times.

<Adhesive layer (X1)>
The pressure-sensitive adhesive layer (X1) contained in the pressure-sensitive adhesive sheet of the present invention has a Young's modulus of 5.0 MPa or less at 23 ° C. Further, the adhesive layer (X1) of the pressure-sensitive adhesive sheet of the present invention has a Young's modulus at 23 ° C. lower than that of the non-thermally expandable base material layer (Y2) at 23 ° C.

The pressure-sensitive adhesive layer (X1) may be a heat-expandable layer or a non-heat-expandable layer, but is preferably a non-heat-expandable layer.
When the pressure-sensitive adhesive layer (X1) is a non-thermally expandable layer, the volume change rate (%) of the pressure-sensitive adhesive layer (X1) calculated from the above formula is less than 5%, preferably less than 2%. It is preferably less than 1%, more preferably less than 0.1%, and even more preferably less than 0.01%.
The pressure-sensitive adhesive layer (X1) preferably does not contain thermal-expandable particles, but may contain thermal-expandable particles within a range not contrary to the object of the present invention. When the pressure-sensitive adhesive layer (X1) contains thermally expandable particles, the smaller the content is, the more preferable, and the content is preferably less than 3% by mass, based on the total mass (100% by mass) of the pressure-sensitive adhesive layer (X1). It is preferably less than 1% by mass, more preferably less than 0.1% by mass, still more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass.

The pressure-sensitive adhesive layer (X1) contained in the pressure-sensitive adhesive sheet of the present invention can be formed from the pressure-sensitive adhesive composition (x-1) containing a pressure-sensitive adhesive resin.
Hereinafter, each component contained in the pressure-sensitive adhesive composition (x-1) will be described.

(Adhesive resin)
Examples of the adhesive resin include polymers having adhesiveness by themselves and having a mass average molecular weight (Mw) of 10,000 or more.
The mass average molecular weight (Mw) of the adhesive resin is preferably 10,000 to 2 million, more preferably 20,000 to 1.5 million, still more preferably 30,000 to 100, from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer (X1). It is ten thousand.

Specific examples of the adhesive resin include rubber-based resins such as acrylic resins, urethane-based resins, and polyisobutylene-based resins, polyester-based resins, olefin-based resins, silicone-based resins, and polyvinyl ether-based resins.
One type of these adhesive resins may be used alone, or two or more types may be used in combination.
When these adhesive resins are copolymers having two or more kinds of structural units, the form of the copolymer is not particularly limited, and block copolymers, random copolymers, and graft copolymers are used. It may be any of the polymers.

The adhesive resin may be an energy ray-curable adhesive resin in which a polymerizable functional group is introduced into the side chain.
Examples of the polymerizable functional group include those having a carbon-carbon double bond such as a (meth) acryloyl group, a vinyl group and an allyl group.
Further, as the energy ray, among the above-mentioned ones, ultraviolet rays that are easy to handle are preferable.

Here, in one aspect of the present invention, the adhesive resin is acrylic from the viewpoint of exhibiting excellent adhesive strength in the pressure-sensitive adhesive layer (X1) and adjusting the Young's modulus of the pressure-sensitive adhesive layer (X1) within the above range. It is preferable to contain a based resin.

The content of the acrylic resin in the adhesive resin is preferably 30 with respect to the total amount (100% by mass) of the adhesive resin contained in the adhesive composition (x-1) or the adhesive layer (X1). It is -100% by mass, more preferably 50 to 100% by mass, still more preferably 70 to 100% by mass, still more preferably 85 to 100% by mass.

(Acrylic resin)
In one aspect of the present invention, the acrylic resin that can be used as the adhesive resin includes, for example, a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, and a cyclic structure. Examples thereof include polymers containing a structural unit derived from (meth) acrylate having.

The mass average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1.5 million, more preferably 200,000 to 1.3 million, still more preferably 350,000 to 1.2 million, and even more preferably 500,000 to 1.1 million. ..

The acrylic resin used in one embodiment of the present invention includes a structural unit (a1) derived from an alkyl (meth) acrylate (a1') (hereinafter, also referred to as "monomer (a1')") and a functional group-containing monomer (a2). An acrylic copolymer (A1) having a structural unit (a2) derived from') (hereinafter, also referred to as "monomer (a2')") is more preferable.

The number of carbon atoms of the alkyl group of the monomer (a1') is preferably from the viewpoint of exhibiting excellent adhesive strength in the pressure-sensitive adhesive layer (X1) and adjusting the Young's modulus of the pressure-sensitive adhesive layer (X1) within the above range. Is 1 to 24, more preferably 1 to 12, still more preferably 2 to 10, and even more preferably 4 to 8.
The alkyl group contained in the monomer (a1') may be a straight chain alkyl group or a branched chain alkyl group.

Examples of the monomer (a1') include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and tridecyl (). Examples thereof include meta) acrylate and stearyl (meth) acrylate.
One of these monomers (a1') may be used alone, or two or more thereof may be used in combination.
As the monomer (a1'), butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.

The content of the structural unit (a1) is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass, based on the total structural unit (100% by mass) of the acrylic copolymer (A1). %, More preferably 70 to 97.0% by mass, and even more preferably 80 to 95.0% by mass.

Examples of the functional group contained in the monomer (a2') include a hydroxyl group, a carboxy group, an amino group, an epoxy group and the like.
That is, examples of the monomer (a2') include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer.
One of these monomers (a2') may be used alone, or two or more thereof may be used in combination.
Among these, as the monomer (a2'), a hydroxyl group-containing monomer and a carboxy group-containing monomer are preferable, and a hydroxyl group-containing monomer is more preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl (meth). ) Hydroxyalkyl (meth) acrylates such as acrylates and 4-hydroxybutyl (meth) acrylates; hydroxyl group-containing compounds such as unsaturated alcohols such as vinyl alcohols and allyl alcohols.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid, and citraconic acid, and their anhydrides. , 2- (Acryloyloxy) ethyl succinate, 2-carboxyethyl (meth) acrylate and the like.

The content of the structural unit (a2) is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, based on the total structural unit (100% by mass) of the acrylic copolymer (A1). %, More preferably 1.0 to 15% by mass, and even more preferably 3.0 to 10% by mass.

The acrylic copolymer (A1) may further have a structural unit (a3) derived from a monomer (a3') other than the monomers (a1') and (a2').
In the acrylic copolymer (A1), the total content of the structural units (a1) and (a2) is preferably relative to the total structural units (100% by mass) of the acrylic copolymer (A1). It is 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass.

Examples of the monomer (a3') include olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene and chloroprene; cyclohexyl (meth) acrylates, It has a cyclic structure such as benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and imide (meth) acrylate. (Meta) Acrylate; Examples thereof include styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmorpholine, and N-vinylpyrrolidone.

Further, the acrylic copolymer (A1) may be an energy ray-curable acrylic copolymer in which a polymerizable functional group is introduced into at least one of a main chain and a side chain.
The polymerizable functional group and the energy ray are as described above.
The polymerizable functional group is a substituent capable of binding to the acrylic copolymer having the above-mentioned structural units (a1) and (a2) and the functional group of the structural unit (a2) of the acrylic copolymer. It can be introduced by reacting with a polymerizable compound (Xa) having a polymerizable functional group.
Examples of the polymerizable compound (Xa) include (meth) acryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, (meth) acryloyl isocyanate, allyl isocyanate, glycidyl (meth) acrylate, and (meth). Acrylic acid and the like can be mentioned.

(Crosslinking agent)
In one aspect of the present invention, when the pressure-sensitive adhesive composition (x-1) contains a pressure-sensitive adhesive resin having a functional group like the above-mentioned acrylic copolymer (A1), it further contains a cross-linking agent. Is preferable.
The cross-linking agent reacts with a tacky resin having a functional group to cross-link the tacky resins with the functional group as a cross-linking starting point.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and metal chelate-based cross-linking agents.
One of these cross-linking agents may be used alone, or two or more thereof may be used in combination.
Among these cross-linking agents, isocyanate-based cross-linking agents are preferable from the viewpoint of increasing the cohesive force to improve the adhesive force and the availability.
Examples of the isocyanate-based cross-linking agent include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; dicyclohexylmethane-4,4'-diisocyanate, bicycloheptane triisocyanate, cyclopentylene diisocyanate, and cyclohexylene diisocyanate. , Methylcyclohexylene diisocyanate, methylenebis (cyclohexylisocyanate), 3-isocyanatemethyl-3,5,5-trimethylcyclohexylisocyanate, and alicyclic polyisocyanates such as hydrogenated xylylene diisocyanate; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, And polyisocyanate compounds such as acyclic aliphatic polyisocyanates such as lysine diisocyanate; and the like.
Examples of the isocyanate-based cross-linking agent include a trimethylolpropane adduct-type modified product of the polyhydric isocyanate compound, a burette-type modified product reacted with water, and an isocyanurate-type modified product containing an isocyanurate ring.
Among these, the isocyanurate ring is used from the viewpoint of suppressing the decrease in elastic modulus of the pressure-sensitive adhesive layer (X1) during heating and suppressing the adhesion of the residue derived from the pressure-sensitive adhesive layer (X1) to the adherend. It is preferable to use an isocyanurate-type modified product containing isocyanurate, more preferably an isocyanurate-type modified product of an acyclic aliphatic polyisocyanate, and further preferably use an isocyanurate-type modified product of hexamethylene diisocyanate.

The content of the cross-linking agent is appropriately adjusted according to the number of functional groups of the adhesive resin, and is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the adhesive resin having functional groups. It is more preferably 0.03 to 7 parts by mass, and further preferably 0.05 to 5 parts by mass. By adjusting the content of the cross-linking agent to the above range, the Young's modulus of the pressure-sensitive adhesive layer (X1) can be easily adjusted to the above range.

(Adhesive agent)
In one aspect of the present invention, the pressure-sensitive adhesive composition (x-1) may further contain a tackifier from the viewpoint of further improving the adhesive strength.
In the present specification, the "tacking agent" refers to a component that supplementarily improves the adhesive strength of the adhesive resin and has a mass average molecular weight (Mw) of less than 10,000, and the above-mentioned adhesive resin. Is distinct from.
The mass average molecular weight (Mw) of the tackifier is less than 10,000, preferably 400 to 9000, more preferably 500 to 8000, and even more preferably 800 to 5000.

As the tackifier, for example, it is obtained by copolymerizing a C5 distillate such as rosin resin, terpene resin, styrene resin, penten, isoprene, piperin, 1,3-pentadiene produced by thermal decomposition of petroleum naphtha. Examples thereof include C5-based petroleum resins, C9-based petroleum resins obtained by copolymerizing C9 distillates such as inden and vinyl toluene produced by thermal decomposition of petroleum naphtha, and hydrides obtained by hydrogenating these.

The softening point of the tackifier is preferably 60 to 170 ° C, more preferably 65 to 160 ° C, and even more preferably 70 to 150 ° C.
In the present specification, the "softening point" of the tackifier means a value measured in accordance with JIS K 2531.
As the tackifier, one type may be used alone, or two or more types having different softening points, structures, etc. may be used in combination. When two or more kinds of tackifiers are used, it is preferable that the weighted average of the softening points of the plurality of tackifiers belongs to the above range.

The content of the tackifier is preferably 0.01 to 65% by mass, more preferably 0.1 to 50% by mass, based on the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition (x-1). %, More preferably 1 to 40% by mass, still more preferably 2 to 30% by mass.

(Photopolymerization initiator)
In one aspect of the present invention, when the pressure-sensitive adhesive composition (x-1) contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive adhesive resin, it preferably further contains a photopolymerization initiator.
By preparing a pressure-sensitive adhesive composition containing an energy ray-curable pressure-sensitive adhesive resin and a photopolymerization initiator, the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition can be subjected to irradiation with relatively low-energy energy rays. The curing reaction can be sufficiently advanced, and the adhesive strength can be adjusted to a desired range.
Examples of the photopolymerization initiator used in one embodiment of the present invention include 1-hydroxy-cyclohexyl-phenylketone, benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin propyl ether, benzylphenyl sulfide, and tetramethylthium. Examples thereof include monosulfide, azobisisobutyrolnitrile, dibenzyl, diacetyl, 8-chloranthraquinone and the like.
One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.

The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and further preferably 0.% by mass with respect to 100 parts by mass of the energy ray-curable adhesive resin. It is 05 to 2 parts by mass.

(Additives for adhesives)
In one aspect of the present invention, the pressure-sensitive adhesive composition (x-1) is an additive for a pressure-sensitive adhesive used in a general pressure-sensitive adhesive in addition to the above-mentioned additives as long as the effect of the present invention is not impaired. May be contained.
Examples of such additives for adhesives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), ultraviolet absorbers and the like.
These adhesive additives may be used alone or in combination of two or more.

When these additives for adhesives are contained, the content of each additive for adhesives is independently, preferably 0.0001 to 20 parts by mass, based on 100 parts by mass of the adhesive resin. It is preferably 0.001 to 10 parts by mass.

(Thickness of the adhesive layer (X1) at 23 ° C.)
In one aspect of the present invention, the thickness of the pressure-sensitive adhesive layer (X1) at 23 ° C. exhibits good adhesive strength, and when the heat-expandable particles are expanded by heating, the thickness of the pressure-sensitive adhesive layer (X1) is increased. From the viewpoint of satisfactorily forming irregularities on the adhesive surface, it is preferably 3 to 10 μm, more preferably 3 to 8 μm, and even more preferably 3 to 7 μm.
By adjusting the thickness of the pressure-sensitive adhesive layer (X1) within the above range, the pressure-sensitive adhesive layer (X1) can be easily formed, and the adhesive surface of the pressure-sensitive adhesive layer (X1) is well formed with irregularities. It can be made easy.
The thickness of the pressure-sensitive adhesive layer (X1) at 23 ° C. is a value measured by the method described in Examples described later.

(The product of the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. and the thickness of the pressure-sensitive adhesive layer (X1) at 23 ° C.)
In one aspect of the present invention, the product of the Young's modulus (unit: MPa) of the pressure-sensitive adhesive layer (X1) at 23 ° C. and the thickness (unit: μm) of the pressure-sensitive adhesive layer (X1) at 23 ° C. is thermally expandable. From the viewpoint of satisfactorily forming irregularities on the adhesive surface of the pressure-sensitive adhesive layer (X1) when the particles are expanded by heating, the content is preferably 0.3 to 50, more preferably 1.0 to 30. It is more preferably 1.5 to 20, and even more preferably 2.0 to 10.

<Thermal expansion substrate layer (Y1)>
The heat-expandable base material layer (Y1) is a base material layer having heat-expandable particles, and is provided between the pressure-sensitive adhesive layer (X1) and the non-heat-expandable base material layer (Y2).
Here, in one aspect of the present invention, the heat-expandable base material layer (Y1) preferably satisfies the following requirement (1).
- Requirement (1): in the expansion starting temperature of the thermally expandable particles (t), thermally expandable base material layer (Y1) storage modulus E of the '(t) is less than or equal to 1.0 × ¹⁰ 7 Pa.
In the present specification, the storage elastic modulus E'of the heat-expandable base material layer (Y1) at a predetermined temperature means a value measured by the method described in Examples.

The above requirement (1) can be said to be an index showing the rigidity of the heat-expandable base material layer (Y1) immediately before the heat-expandable particles expand.
Before the expansion of the thermally expandable particles, the storage elastic modulus E'of the thermally expandable base material layer (Y1) decreases as the temperature rises. However, before and after reaching the expansion start temperature (t) of the thermally expandable particles, the thermally expandable particles start to expand, so that the decrease in the storage elastic modulus E'of the thermally expandable base material layer (Y1) is suppressed. To.
On the other hand, in order to facilitate the formation of irregularities on the adhesive surface of the pressure-sensitive adhesive layer (X1), the heat-expandable base material layer (Y1) is adhered by heating to a temperature equal to or higher than the expansion start temperature (t). It is necessary to make it easy for irregularities to be formed on the surface on the agent layer (X1) side. In the heat-expandable base layer (Y1) that satisfies the above requirement (1), the heat-expandable particles expand at the expansion start temperature (t) to become sufficiently large, and the pressure-sensitive adhesive of the heat-expandable base layer (Y1). Unevenness is likely to be formed on the surface on the layer (X1) side. Therefore, unevenness is likely to be formed on the adhesive surface of the adhesive layer (X1).

In one aspect of the present invention, the storage elastic modulus E'(t) defined in the requirement (1) of the heat-expandable base material layer (Y1) is preferably 9.0 × 10 ⁶ Pa or less from the above viewpoint. It is preferably 8.0 × 10 ⁶ Pa or less, more preferably 6.0 × 10 ⁶ Pa or less, and even more preferably 4.0 × 10 ⁶ Pa or less.
Further, the flow of the expanded heat-expandable particles is suppressed, the shape retention of the unevenness formed on the surface of the heat-expandable base material layer (Y1) on the pressure-sensitive adhesive layer (X1) side is improved, and the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer) From the viewpoint of making it easy for irregularities to be formed on the adhesive surface of X1), the storage elastic modulus E'(t) specified in the requirement (1) of the thermally expandable base material layer (Y1) is preferably 1.0 ×. It is 10 ³ Pa or more, more preferably 1.0 × 10 ⁴ Pa or more, and further preferably 1.0 × 10 ⁵ Pa or more.

From the viewpoint of forming the heat-expandable base material layer (Y1) satisfying the above requirement (1), the content of the heat-expandable particles in the heat-expandable base material layer (Y1) is the heat-expandable base material layer (Y1). It is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, still more preferably 10 to 30% by mass, still more preferably 15 to 25% by mass, based on the total mass (100% by mass) of the above.

Further, in one aspect of the present invention, the Young's modulus of the heat-expandable base material layer (Y1) at 23 ° C. is larger than the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C., and the non-heat-expandable base material layer. It is preferably larger than the Young's modulus of (Y2) at 23 ° C.
Specifically, the Young's modulus of the heat-expandable base material layer (Y1) at 23 ° C. is preferably 100 MPa or more, more preferably 200 MPa or more, still more preferably 300 MPa or more. Further, it is usually 600 MPa or less, preferably 500 MPa or less.

From the viewpoint of improving the interlayer adhesion between the heat-expandable base material layer (Y1) and other layers to be laminated, the surface of the heat-expandable base material layer (Y1) is subjected to an oxidation method, an unevenness method, or the like. Surface treatment, easy adhesion treatment, or primer treatment may be performed.
Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone, and ultraviolet irradiation treatment, and examples of the unevenness method include sandblasting method and solvent treatment method. And so on.

The heat-expandable base material layer (Y1) is preferably formed from a resin composition (y-1) containing a resin and heat-expandable particles.
The resin composition (y-1) may contain an additive for a base material, if necessary, as long as the effects of the present invention are not impaired.
Examples of the base material additive include an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, and a colorant.
These base material additives may be used alone or in combination of two or more.
When these base material additives are contained, the content of each base material additive is independently, preferably 0.0001 to 20 parts by mass, more preferably 0.0001 to 20 parts by mass with respect to 100 parts by mass of the resin. Is 0.001 to 10 parts by mass.

The heat-expandable particles contained in the resin composition (y-1), which is a material for forming the heat-expandable base material layer (Y1), are as described above.
The content of the heat-expandable particles is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, still more preferably, with respect to the total amount (100% by mass) of the active ingredient of the resin composition (y-1). Is 10 to 30% by mass, more preferably 15 to 25% by mass.

The resin contained in the resin composition (y-1) which is the material for forming the heat-expandable base material layer (Y1) may be a non-adhesive resin or an adhesive resin.
That is, even if the resin contained in the resin composition (y-1) is an adhesive resin, the adhesiveness is obtained in the process of forming the heat-expandable base material layer (Y1) from the resin composition (y-1). It is sufficient that the resin polymerizes with the polymerizable compound, the obtained resin becomes a non-adhesive resin, and the heat-expandable base material layer (Y1) containing the resin becomes non-adhesive.

The mass average molecular weight (Mw) of the resin contained in the resin composition (y-1) is preferably 10 to 1,000,000, more preferably 10 to 700,000, and even more preferably 10 to 500,000.
When the resin is a copolymer having two or more kinds of structural units, the form of the copolymer is not particularly limited, and any of a block copolymer, a random copolymer, and a graft copolymer can be used. It may be.

The content of the resin is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, still more preferably 65 to 65% by mass, based on the total amount (100% by mass) of the active ingredient of the resin composition (y-1). It is 90% by mass, more preferably 70 to 85% by mass.

From the viewpoint of forming the heat-expandable base material layer (Y1) satisfying the above requirement (1), the resin contained in the resin composition (y-1) is selected from acrylic urethane-based resin and olefin-based resin. It is preferable to include one or more of these.
Further, as the acrylic urethane resin, the following resin (U1) is preferable.
-Acrylic urethane resin (U1) obtained by polymerizing a urethane prepolymer (UP) and a vinyl compound containing a (meth) acrylic acid ester.

(Acrylic urethane resin (U1))
Examples of the urethane prepolymer (UP) that serves as the main chain of the acrylic urethane resin (U1) include a reaction product of a polyol and a multivalent isocyanate.
The urethane prepolymer (UP) is preferably obtained by further performing a chain extension reaction using a chain extender.

Examples of the polyol which is a raw material of the urethane prepolymer (UP) include an alkylene type polyol, an ether type polyol, an ester type polyol, an ester amide type polyol, an ester ether type polyol, and a carbonate type polyol.
One of these polyols may be used alone, or two or more thereof may be used in combination.
As the polyol used in one aspect of the present invention, a diol is preferable, an ester type diol, an alkylene type diol and a carbonate type diol are more preferable, and an ester type diol and a carbonate type diol are further preferable.

Examples of the ester-type diol include alkanediols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol; ethylene glycol, propylene glycol, and the like. One or more selected from diols such as diethylene glycol, alkylene glycol such as dipropylene glycol; and phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, diphenylmethane-4. , 4'-dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, hetic acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, hexa Examples thereof include dicarboxylic acids such as hydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, and methylhexahydrophthalic acid, and one or more selected from these anhydrides.
Specifically, polyethylene adipatediol, polybutylene adipatediol, polyhexamethylene adipatediol, polyhexamethyleneisophthalatediol, polyneopentyl adipatediol, polyethylenepropylene adipatediol, polyethylenebutylene adipatediol, polybutylenehexamethylene adipatediol, Polydiethylene adipatediol, poly (polytetramethylene ether) adipatediol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sevacate diol, polybutylene azelate diol, polybutylene sebacate diol and polyneo Examples thereof include pentyl terephthalate diol.

Examples of the alkylene-type diol include alkanediols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol; ethylene glycol, propylene glycol, and the like. Examples thereof include alkylene glycols such as diethylene glycol and dipropylene glycol; polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol; and polyoxyalkylene glycols such as polytetramethylene glycol.

Examples of the carbonate type diol include 1,4-tetramethylene carbonate diol, 1,5-pentamethylene carbonate diol, 1,6-hexamethylene carbonate diol, 1,2-propylene carbonate diol, and 1,3-propylene carbonate diol. , 2,2-Dimethylpropylene carbonate diol, 1,7-heptamethylene carbonate diol, 1,8-octamethylene carbonate diol, 1,4-cyclohexane carbonate diol and the like.

Examples of the polyisocyanate used as a raw material for the urethane prepolymer (UP) include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates.
One of these polyvalent isocyanates may be used alone, or two or more thereof may be used in combination.
Further, these polyvalent isocyanates may be a trimethylolpropane adduct-type modified product, a biuret-type modified product reacted with water, or an isocyanurate-type modified product containing an isocyanurate ring.

Among these, diisocyanate is preferable as the polyvalent isocyanate used in one embodiment of the present invention, and 4,4'-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6. -One or more selected from tolylene diisocyanate (2,6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate are more preferable.

Examples of the alicyclic diisocyanate include 3-isocyanate methyl-3,5,5-trimethylcyclohexylisocyanate (isophorone diisocyanate, IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, and 1,4-cyclohexane. Examples thereof include diisocyanate, methyl-2,4-cyclohexanediisocyanate and methyl-2,6-cyclohexanediisocyanate, but isophorone diisocyanate (IPDI) is preferable.

In one aspect of the present invention, the urethane prepolymer (UP) serving as the main chain of the acrylic urethane resin (U1) is a reaction product of a diol and a diisocyanate, and is a straight chain having ethylenically unsaturated groups at both ends. Urethane prepolymers are preferred.
As a method for introducing an ethylenically unsaturated group into both ends of the linear urethane prepolymer, an NCO group at the terminal of the linear urethane prepolymer formed by reacting a diol and a diisocyanate compound and a hydroxyalkyl (meth) acrylate There is a method of reacting with.

Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy. Examples thereof include butyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate.

The vinyl compound that forms the side chain of the acrylic urethane resin (U1) contains at least (meth) acrylic acid ester.
As the (meth) acrylic acid ester, one or more selected from alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate is preferable, and alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate are more preferably used in combination.

When alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate are used in combination, the blending ratio of hydroxyalkyl (meth) acrylate to 100 parts by mass of alkyl (meth) acrylate is preferably 0.1 to 100 parts by mass. It is preferably 0.5 to 30 parts by mass, more preferably 1.0 to 20 parts by mass, and even more preferably 1.5 to 10 parts by mass.

The alkyl group of the alkyl (meth) acrylate has preferably 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, still more preferably 1 to 8 carbon atoms, and even more preferably 1 to 3 carbon atoms.

Moreover, as the hydroxyalkyl (meth) acrylate, the same hydroxyalkyl (meth) acrylate used for introducing an ethylenically unsaturated group into both ends of the above-mentioned linear urethane prepolymer can be mentioned.

Examples of vinyl compounds other than (meth) acrylic acid ester include aromatic hydrocarbon-based vinyl compounds such as styrene, α-methylstyrene and vinyltoluene; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl acetate and vinyl propionate. , (Meta) acrylonitrile, N-vinylpyrrolidone, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, polar group-containing monomers such as meta (acrylamide); and the like.
One of these may be used alone, or two or more thereof may be used in combination.

The content of the (meth) acrylic acid ester in the vinyl compound is preferably 40 to 100% by mass, more preferably 65 to 100% by mass, still more preferably, based on the total amount (100% by mass) of the vinyl compound. It is 80 to 100% by mass, more preferably 90 to 100% by mass.

The total content of the alkyl (meth) acrylate and the hydroxyalkyl (meth) acrylate in the vinyl compound is preferably 40 to 100% by mass, more preferably 65 to 100% by mass, based on the total amount (100% by mass) of the vinyl compound. It is 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass.

The acrylic urethane resin (U1) used in one embodiment of the present invention is obtained by mixing a urethane prepolymer (UP) and a vinyl compound containing a (meth) acrylic acid ester and polymerizing both.
In the polymerization, it is preferable to further add a radical initiator.

In the acrylic urethane resin (U1) used in one embodiment of the present invention, the content ratio of the structural unit (u11) derived from the urethane prepolymer (UP) and the structural unit (u12) derived from the vinyl compound [(u11). ) / (U12)], preferably 10/90 to 80/20, more preferably 20/80 to 70/30, still more preferably 30/70 to 60/40, still more preferably 35 in terms of mass ratio. / 65-55 / 45.

(Olefin resin)
The olefin-based resin suitable as the resin contained in the resin composition (y-1) is a polymer having at least a structural unit derived from an olefin monomer.
The olefin monomer is preferably an α-olefin having 2 to 8 carbon atoms, and specific examples thereof include ethylene, propylene, butylene, isobutylene, and 1-hexene.
Among these, ethylene and propylene are preferable.

Specific olefinic resins, for example, ultra low density polyethylene (VLDPE, density: 880 kg / ^{m 3} or more 910 kg / ^m less than ^3), low density polyethylene (LDPE, density: 910 kg / ^{m 3} or more 915 kg / ^m less than ³ ), Medium density polyethylene (MDPE, density: 915 kg / m ³ or more and less than 942 kg / m ³ ), high density polyethylene (HDPE, density: 942 kg / m ³ or more), linear low density polyethylene and other polyethylene resins; polypropylene resin (PP); Polybutene resin (PB); Ethylene-propylene copolymer; Olefin-based elastomer (TPO); Poly (4-methyl-1-pentene) (PMP); Ethylene-vinyl acetate copolymer (EVA); Ethylene -Vinyl alcohol copolymer (EVOH); olefin-based ternary copolymer such as ethylene-propylene- (5-ethylidene-2-norbornene); and the like.

In one aspect of the present invention, the olefin resin may be a modified olefin resin further subjected to one or more modifications selected from acid modification, hydroxyl group modification, and acrylic modification.

For example, the acid-modified olefin-based resin obtained by acid-modifying an olefin-based resin is a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or an anhydride thereof with the above-mentioned non-modified olefin-based resin. Can be mentioned.
Examples of the unsaturated carboxylic acid or its anhydride include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth) acrylic acid, maleic anhydride, and itaconic anhydride. , Glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornendicarboxylic acid anhydride, tetrahydrophthalic anhydride and the like.
The unsaturated carboxylic acid or its anhydride may be used alone or in combination of two or more.

The acrylic-modified olefin-based resin obtained by subjecting the olefin-based resin to acrylic modification is a modification obtained by graft-polymerizing an alkyl (meth) acrylate as a side chain to the above-mentioned non-modified olefin-based resin which is the main chain. Polymers can be mentioned.
The alkyl group of the above alkyl (meth) acrylate has preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and further preferably 1 to 12 carbon atoms.
Examples of the above-mentioned alkyl (meth) acrylate include the same compounds as those that can be selected as the monomer (a1') described later.

Examples of the hydroxyl group-modified olefin resin obtained by subjecting the olefin resin to hydroxyl group modification include a modified polymer obtained by graft-polymerizing a hydroxyl group-containing compound on the above-mentioned non-modified olefin resin which is the main chain.
Examples of the above-mentioned hydroxyl group-containing compound include the same as the above-mentioned hydroxyl group-containing compound.

(Resin other than acrylic urethane resin and olefin resin)
In one aspect of the present invention, the resin composition (y-1) may contain a resin other than the acrylic urethane-based resin and the olefin-based resin as long as the effects of the present invention are not impaired.
Examples of such resins include vinyl resins such as polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene co-weight. Combined; cellulose triacetate; polycarbonate; polyurethane not applicable to acrylic urethane resin; polysulfone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resin such as polyetherimide and polyimide; polyamide resin; acrylic resin; Fluorine-based resin and the like can be mentioned.

However, from the viewpoint of forming the heat-expandable base material layer (Y1) satisfying the above requirement (1), the content of the acrylic urethane resin and the resin other than the olefin resin in the resin composition (y-1) is determined. Less is preferable.
The content of the resin other than the acrylic urethane resin and the olefin resin is preferably less than 30 parts by mass, more preferably 20 parts by mass with respect to 100 parts by mass of the total amount of the resin contained in the resin composition (y-1). It is less than parts by mass, more preferably less than 10 parts by mass, still more preferably less than 5 parts by mass, and even more preferably less than 1 part by mass.

(Solvent-free resin composition (y-1a))
As one aspect of the resin composition (y-1) used in one aspect of the present invention, an oligomer having an ethylenically unsaturated group having a mass average molecular weight (Mw) of 50,000 or less, an energy ray-polymerizable monomer, and the above-mentioned heat. Examples thereof include a solvent-free resin composition (y-1a) containing expandable particles and not containing a solvent.
In the solvent-free resin composition (y-1a), no solvent is blended, but the energy ray-polymerizable monomer contributes to the improvement of the plasticity of the oligomer.
By irradiating the coating film formed from the solvent-free resin composition (y-1a) with energy rays, it is easy to form a heat-expandable base material layer (Y1) satisfying the above requirement (1).

The types and shapes of the heat-expandable particles to be blended in the solvent-free resin composition (y-1a) and the blending amount (content) are as described above.

The mass average molecular weight (Mw) of the oligomer contained in the solvent-free resin composition (y-1a) is 50,000 or less, preferably 1000 to 50,000, more preferably 2000 to 40,000, still more preferably 3000 to 35,000. , Even more preferably 4000 to 30,000.

The oligomer may be any resin contained in the above-mentioned resin composition (y-1) having an ethylenically unsaturated group having a mass average molecular weight of 50,000 or less, and the above-mentioned urethane prepolymer. (UP) is preferable.
As the oligomer, a modified olefin resin having an ethylenically unsaturated group can also be used.

The total content of the oligomer and the energy ray-polymerizable monomer in the solvent-free resin composition (y-1a) is based on the total amount (100% by mass) of the solvent-free resin composition (y-1a). It is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, still more preferably 65 to 90% by mass, and even more preferably 70 to 85% by mass.

Examples of the energy ray-polymerizable monomer include isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, and adamantan (). Alicyclic polymerizable compounds such as meta) acrylates and tricyclodecane acrylates; aromatic polymerizable compounds such as phenylhydroxypropyl acrylates, benzyl acrylates and phenolethylene oxide modified acrylates; tetrahydrofurfuryl (meth) acrylates, morpholine acrylates, N- Examples thereof include heterocyclic polymerizable compounds such as vinylpyrrolidone and N-vinylcaprolactam.
One of these energy ray-polymerizable monomers may be used alone, or two or more thereof may be used in combination.

The content ratio [oligomer / energy ray-polymerizable monomer] of the oligomer to the energy ray-polymerizable monomer in the solvent-free resin composition (y-1a) is preferably 20/80 to 20/80 in mass ratio. It is 90/10, more preferably 30/70 to 85/15, and even more preferably 35/65 to 80/20.

In one aspect of the present invention, the solvent-free resin composition (y-1a) is preferably further blended with a photopolymerization initiator.
By containing the photopolymerization initiator, the curing reaction can be sufficiently advanced even by irradiation with relatively low energy energy rays.

Examples of the photopolymerization initiator include the same photopolymerization initiators that the pressure-sensitive adhesive composition (x-1) may contain.
One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.

The blending amount of the photopolymerization initiator is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 4 parts by mass, and further, based on the total amount (100 parts by mass) of the oligomer and the energy ray-polymerizable monomer. It is preferably 0.02 to 3 parts by mass.

(Thickness of thermally expandable base material layer (Y1))
In one aspect of the present invention, the thickness of the heat-expandable substrate layer (Y1) is preferably 10 to 1000 μm, more preferably 20 to 500 μm, still more preferably 25 to 400 μm, still more preferably 30 to 300 μm. ..

<Non-thermally expandable base material layer (Y2)>
The non-thermally expandable base material layer (Y2) contained in the pressure-sensitive adhesive sheet of the present invention is provided on the surface of the heat-expandable base material layer (Y1) opposite to the laminated surface of the pressure-sensitive adhesive layer (X1). In the pressure-sensitive adhesive sheet of the present invention, the Young's modulus of the non-thermally expandable base material layer (Y2) at 23 ° C. is higher than the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. Therefore, when the heat-expandable particles are expanded, the heat-expandable base layer (Y1) is more adherent than the surface of the heat-expandable base layer (Y1) on the non-heat-expandable base layer (Y2) side. Unevenness is likely to be formed on the surface of the agent layer (X1) side. Therefore, unevenness is satisfactorily formed on the adhesive surface of the adhesive layer (X1).
From this point of view, the Young's modulus of the non-thermally expandable base material layer (Y2) at 23 ° C. is preferably 700 MPa or more, more preferably 1000 MPa or more, still more preferably 1300 MPa or more, still more preferably 1600 MPa or more, still more preferably. It is 1800 MPa or more. In addition, it is usually 10,000 MPa or less.

Examples of the material for forming the non-thermally expandable base material layer (Y2) include resins, metals, and paper materials, which can be appropriately selected depending on the use of the pressure-sensitive adhesive sheet according to one aspect of the present invention.

Examples of the resin 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; polyethylene terephthalate and poly. Polyimide-based resins such as butylene terephthalate and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; polyether ether ketone; Polyether sulfone; polyphenylene sulfide; polyimide resin such as polyetherimide and polyimide; polyamide resin; acrylic resin; fluorine resin and the like can be mentioned.
Examples of the metal include aluminum, tin, chromium, titanium and the like.
Examples of the paper material include thin-leaf paper, medium-quality paper, high-quality paper, impregnated paper, coated paper, art paper, parchment paper, and glassin paper.
Among these, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are preferable.

These forming materials may be composed of one kind, or two or more kinds may be used in combination.
As the non-thermally expandable base material layer (Y2) in which two or more kinds of forming materials are used in combination, a paper material laminated with a thermoplastic resin such as polyethylene, or a metal film is formed on the surface of a resin film or sheet containing the resin. Examples thereof include those formed.
As a method for forming the metal layer, for example, a method of vapor-depositing the metal by a PVD method such as vacuum vapor deposition, sputtering, or ion plating, or a method of attaching a metal foil made of the metal by using a general adhesive. The method of doing this can be mentioned.

When the non-thermally expandable base material layer (Y2) contains a resin, it is a non-thermally expandable group from the viewpoint of improving the interlayer adhesion between the non-thermally expandable base material layer (Y2) and other layers to be laminated. The surface of the material layer (Y2) may also be subjected to surface treatment, easy adhesion treatment, or primer treatment by an oxidation method, an unevenness method, or the like, similarly to the above-mentioned thermal expansion base material layer (Y1). ..

Further, when the non-thermally expandable base material layer (Y2) contains a resin, the above-mentioned base material additive which can be contained in the resin composition (y-1) may be contained together with the resin.

The non-thermally expandable base material layer (Y2) is a non-thermally expandable layer determined based on the above method.
Therefore, the volume change rate (%) of the non-thermally expandable base material layer (Y2) calculated from the above formula is less than 5%, but preferably less than 2%, more preferably less than 1%, and further. It is preferably less than 0.1%, and even more preferably less than 0.01%.

Further, the non-thermally expandable base material layer (Y2) may contain thermally expandable particles as long as the volume change rate is within the above range. For example, by selecting the resin contained in the non-thermally expandable base material layer (Y2), it is possible to adjust the volume change rate within the above range even if the thermally expandable particles are contained.
However, the smaller the content of the heat-expandable particles in the non-heat-expandable base material layer (Y2), the more preferable.
The specific content of the heat-expandable particles is usually less than 3% by mass, preferably less than 1% by mass, more preferably with respect to the total mass (100% by mass) of the non-heat-expandable base material layer (Y2). Is less than 0.1% by mass, more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass. Even more preferably, it does not contain thermally expandable particles.

(Storage modulus of non-thermally expandable base material (Y2) at 23 ° C. E'(23))
The storage elastic modulus E'(23) of the non-thermally expandable substrate layer (Y2) at 23 ° C. is preferably 5.0 × 10 ⁷ to 5.0 × 10 ⁹ Pa, more preferably 5.0 × 10 ^8. It is ~ 4.5 × 10 ⁹ Pa, more preferably 1.0 × 10 ⁹ to 4.0 × 10 ⁹ Pa.
If the storage elastic modulus E of the non-heat-expandable base material layer (Y2) '(23) is 5.0 × ¹⁰ 7 Pa or more, heat-expandable base layer non-intumescent base material layer (Y1) ( It is easy to effectively suppress the expansion of the surface on the Y2) side, and it is easy to improve the deformation resistance of the adhesive sheet. On the other hand, if non-heat-expandable base material layer (Y2) of the storage modulus E '(23) is less than 5.0 × ¹⁰ 9 Pa, to improve the handling properties of the pressure-sensitive adhesive sheet easily.
In the present specification, the storage elastic modulus E'(23) of the non-thermally expandable base material layer (Y2) means a value measured by the method described in Examples.

(Storage modulus E'(t) at the expansion start temperature (t) of the non-thermally expandable base material layer (Y2))
The coefficient of thermal expansion E'(t) at the expansion start temperature (t) of the thermally expandable particles of the non-thermally expandable substrate layer (Y2) is preferably 5.0 × 10 ⁷ to 3.0 × 10 ⁹ Pa. It is more preferably 2.0 × 10 ⁸ to 2.5 × 10 ⁹ Pa, and even more preferably 5.0 × 10 ⁸ to 2.0 × 10 ⁹ Pa.
If the storage elastic modulus E of the non-heat-expandable base material layer (Y2) '(t) is 5.0 × 10 7 ^Pa or more, heat-expandable base layer non-intumescent base material layer (Y1) ( It is easy to effectively suppress the expansion of the surface on the Y2) side, and it is easy to improve the deformation resistance of the adhesive sheet. On the other hand, if non-heat-expandable base material layer (Y2) storage modulus E '(t) is 3.0 × 10 9 ^Pa or less, to improve the handling properties of the pressure-sensitive adhesive sheet easily.
In the present specification, the storage elastic modulus E'(t) of the non-thermally expandable base material layer (Y2) means a value measured by the method described in Examples.

(Thickness of non-thermally expandable base material layer (Y2))
The thickness of the non-thermally expandable base material layer (Y2) 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 non-thermally expandable base material layer (Y2) is 5 μm or more, the deformation resistance of the pressure-sensitive adhesive sheet can be easily improved. On the other hand, when the thickness of the non-thermally expandable base material layer (Y2) is 500 μm or less, the handleability of the pressure-sensitive adhesive sheet can be easily improved.
In addition, in this specification, the thickness of the non-thermally expandable base material layer (Y2) means the value measured by the method described in Example.

<Adhesive layer (X2)>
The pressure-sensitive adhesive layer (X2) is a layer arbitrarily provided on a surface of the non-thermally expandable base material layer (Y2) opposite to the laminated surface of the heat-expandable base material layer (Y1).
The pressure-sensitive adhesive layer (X2) may be a thermally expandable layer or a non-thermally expandable layer, but is preferably a non-thermally expandable layer. The pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) have different action mechanisms for reducing the adhesive strength of the pressure-sensitive adhesive layer, whereby the treatment for reducing the adhesive strength of one of the pressure-sensitive adhesive layers is performed. When doing so, it is possible to prevent the adhesive strength of the other adhesive layer from being unintentionally reduced.

When the pressure-sensitive adhesive layer (X2) is a non-thermally expandable layer, the volume change rate (%) of the pressure-sensitive adhesive layer (X2) calculated from the above formula is less than 5%, preferably less than 2%. It is preferably less than 1%, more preferably less than 0.1%, and even more preferably less than 0.01%.
The pressure-sensitive adhesive layer (X2) preferably does not contain heat-expandable particles, but may contain heat-expandable particles within a range not contrary to the object of the present invention.
When the pressure-sensitive adhesive layer (X2) contains thermally expandable particles, the smaller the content is, the more preferable, and the content is preferably less than 3% by mass, based on the total mass (100% by mass) of the pressure-sensitive adhesive layer (X2). It is preferably less than 1% by mass, more preferably less than 0.1% by mass, still more preferably less than 0.01% by mass, and even more preferably less than 0.001% by mass.

The pressure-sensitive adhesive layer (X2) is preferably formed from the pressure-sensitive adhesive composition (x-2) containing a pressure-sensitive adhesive resin. Hereinafter, each component contained in the pressure-sensitive adhesive composition (x-2) will be described.

(Adhesive composition (x-2))
The pressure-sensitive adhesive composition (x-2) contains a pressure-sensitive resin, and if necessary, a cross-linking agent, a pressure-sensitive adhesive, a polymerizable compound, a polymerization initiator, and general pressure-sensitive adhesive other than the above-mentioned components. It may contain an additive for a pressure-sensitive adhesive used in the agent.

(Adhesive resin)
The adhesive resin may be a polymer having adhesiveness by itself and having a mass average molecular weight (Mw) of 10,000 or more.
The mass average molecular weight (Mw) of the adhesive resin is preferably 10,000 to 2 million, more preferably 20,000 to 1.5 million, and further preferably 30,000 from the viewpoint of further improving the adhesive strength of the pressure-sensitive adhesive layer (X2). ~ 1 million.

Examples of the adhesive resin include those similar to the adhesive composition contained in the adhesive composition (x-1).
One type of these adhesive resins may be used alone, or two or more types may be used in combination.
When these adhesive resins are copolymers having two or more kinds of structural units, the form of the copolymer may be any of a block copolymer, a random copolymer, and a graft copolymer. There may be.

The adhesive resin contained in the pressure-sensitive adhesive composition (x-2) has a pressure-sensitive adhesive composition containing the pressure-sensitive adhesive resin from the viewpoint of differentiating the mechanism of action of reducing the adhesive strength with the pressure-sensitive adhesive layer (X1). x-2) is preferably a pressure-sensitive adhesive composition that is cured by irradiation with energy rays, and more preferably a pressure-sensitive adhesive composition having an energy ray-polymerizable functional group in the side chain. By forming from the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer (X2) can be made into a pressure-sensitive adhesive layer that is cured by energy ray irradiation and whose adhesive strength is reduced. As a result, the adhesive surface of the pressure-sensitive adhesive layer (X1) can be in a mode in which the adhesive strength is reduced by heating, and the adhesive surface of the pressure-sensitive adhesive layer (X2) can be in a mode in which the adhesive strength is reduced by irradiation with energy rays. The mechanism of action that reduces the adhesive strength of the pressure-sensitive adhesive layer can be different. Therefore, it is possible to prevent the adhesive strength of one of the pressure-sensitive adhesive layers from being unintentionally reduced when the treatment is performed to reduce the adhesive strength of the other pressure-sensitive adhesive layer.
Examples of the energy ray-polymerizable functional group include those having a carbon-carbon double bond such as a (meth) acryloyl group, a vinyl group, and an allyl group.
Among the above-mentioned energy rays, ultraviolet rays, which are easy to handle, are preferable.

When the pressure-sensitive adhesive composition (x-2) is a pressure-sensitive adhesive composition that is cured by irradiation with energy rays, the pressure-sensitive adhesive composition preferably further contains a photopolymerization initiator.
By containing the photopolymerization initiator, the polymerization of the energy ray-polymerizable component can proceed more efficiently.
Examples of the photopolymerization initiator include the same photopolymerization initiators that may be contained in the pressure-sensitive adhesive composition (x-1).
The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, based on 100 parts by mass of the total amount of the adhesive resin having an energy ray-polymerizable functional group. More preferably, it is 0.05 to 2 parts by mass.

The adhesive resin preferably contains an acrylic resin from the viewpoint of exhibiting excellent adhesive strength.
The content of the acrylic resin in the pressure-sensitive adhesive composition (x-2) is preferably 30 to 30% with respect to the total amount (100% by mass) of the pressure-sensitive resin contained in the pressure-sensitive adhesive composition (x-2). It is 100% by mass, more preferably 50 to 100% by mass, still more preferably 70 to 100% by mass, and even more preferably 85 to 100% by mass.

The content of the pressure-sensitive resin in the pressure-sensitive adhesive composition (x-2) is preferably 35 to 100% by mass, based on the total amount (100% by mass) of the active ingredients of the pressure-sensitive adhesive composition (x-2). It is more preferably 50 to 100% by mass, further preferably 60 to 98% by mass, and even more preferably 70 to 95% by mass.

(Crosslinking agent)
In one aspect of the present invention, when the pressure-sensitive adhesive composition (x-2) contains a pressure-sensitive adhesive resin having a functional group, the pressure-sensitive adhesive composition (x-2) preferably further contains a cross-linking agent.
The cross-linking agent reacts with a tacky resin having a functional group to cross-link the tacky resins with the functional group as a cross-linking starting point.

Examples of the cross-linking agent that may be contained in the pressure-sensitive adhesive composition (x-2) include those equivalent to the cross-linking agent that may be contained in the pressure-sensitive adhesive composition (x-1), but have a cohesive force. An isocyanate-based cross-linking agent is preferable from the viewpoint of increasing the adhesive strength and improving the adhesive strength, and from the viewpoint of easy availability.

The content of the cross-linking agent is appropriately adjusted according to the number of functional groups of the adhesive resin, and is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the adhesive resin having functional groups. It is more preferably 0.03 to 7 parts by mass, and further preferably 0.05 to 5 parts by mass.

(Adhesive agent)
In one aspect of the present invention, the pressure-sensitive adhesive composition (x-2) may further contain a pressure-sensitive adhesive from the viewpoint of further improving the adhesive strength.
As the pressure-sensitive adhesive that may be contained in the pressure-sensitive adhesive composition (x-2), the same pressure-imparting agent that may be contained in the pressure-sensitive adhesive composition (x-1) may be used. it can.

(Additives for adhesives)
Examples of the pressure-sensitive adhesive additive include the same pressure-sensitive adhesive additives that the pressure-sensitive adhesive composition (x-1) may contain.

The pressure-sensitive adhesive composition (x-2) can be produced by mixing a pressure-sensitive resin, a cross-linking agent used as necessary, a pressure-sensitive adhesive, an additive for pressure-sensitive adhesive, and the like.

(Thickness of the adhesive layer (X2) at 23 ° C.)
The thickness of the pressure-sensitive adhesive layer (X2) at 23 ° C. is preferably 5 to 150 μm, more preferably 8 to 100 μm, still more preferably 12 to 70 μm, and even more preferably 15 to 50 μm.
If the thickness of the pressure-sensitive adhesive layer (X2) at 23 ° C. is 5 μm or more, sufficient adhesive strength can be easily obtained, and unintentional peeling from the adherend during temporary fixing, misalignment of the adherend, etc. can occur. It tends to be suppressed. On the other hand, if the thickness of the pressure-sensitive adhesive layer (X2) at 23 ° C. is 150 μm or less, the pressure-sensitive adhesive sheet tends to be easy to handle.

<Release material>
Examples of the release material include a release sheet that has undergone double-sided release treatment, a release sheet that has undergone single-sided release treatment, and the like, in which a release agent is applied onto a base material for the release material.
Examples of the base material for the release material include plastic films and papers. Examples of the plastic film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin; and olefin resin films such as polypropylene resin and polyethylene resin. Examples of papers include high-quality paper. , Glassin paper, kraft paper, etc.

Examples of the release agent include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins, and butadiene-based resins; long-chain alkyl-based resins, alkyd-based resins, and fluorine-based resins. As the release agent, one type may be used alone, or two or more types may be used in combination.

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

[Manufacturing method of adhesive sheet]
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited, and examples thereof include a method for manufacturing a pressure-sensitive adhesive sheet having the following steps (1a) to (3a).
Step (1a): A step of applying the pressure-sensitive adhesive composition (x-1) on the peeling-treated surface of the release material to form the pressure-sensitive adhesive layer (X1).
Step (2a): The resin composition (y-1) is applied to one side of the non-thermally expandable base material layer (Y2) to form a non-thermally expandable base material layer (Y2) and a heat-expandable base material layer (Y-1). A step of forming a base material laminate in which Y1) is laminated.
Step (3a): The adhesive surface of the pressure-sensitive adhesive layer (X1) formed in the step (1a) and the surface of the base material laminate formed in the step (2a) on the heat-expandable base material layer (Y1) side. , The process of laminating.

Further, as another method for producing the pressure-sensitive adhesive sheet of the present invention, there is a method for manufacturing a double-sided pressure-sensitive adhesive sheet having the above-mentioned steps (4a) to (5a) in addition to the above-mentioned steps (1a) to (3a).
Step (4a): A step of applying the pressure-sensitive adhesive composition (x-2) on the peeling-treated surface of the release material to form the pressure-sensitive adhesive layer (X2).
Step (5a): A step of adhering the adhesive surface of the pressure-sensitive adhesive layer (X2) formed in step (4a) to the surface of the non-thermally expandable base material layer (Y2) of the pressure-sensitive adhesive sheet formed in step (3a).

In the method for producing the pressure-sensitive adhesive sheet, the resin composition (y-1), the pressure-sensitive adhesive composition (x-1), and the pressure-sensitive adhesive composition (x-2) are further blended with a diluting solvent to form a solution. May be good.
Examples of the coating method include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, and a gravure coating method.

Further, the step of drying the coating film formed from the resin composition (y-1), the pressure-sensitive adhesive composition (x-1), and the pressure-sensitive adhesive composition (x-2) causes the expansion of the heat-expandable particles. From the viewpoint of suppressing, it is preferable that the drying temperature is lower than the expansion start temperature (t) of the thermally expandable particles.

[Use and Usage of Adhesive Sheet of the Present Invention]
The pressure-sensitive adhesive sheet according to one aspect of the present invention can be easily peeled off by heating the temporarily fixed adherend, and can suppress contamination of the adherend surface after peeling, and is applicable to various applications. It is possible. Specifically, for example, a dicing sheet used when dicing an adherend such as a semiconductor wafer, a back grind sheet used in a process of grinding an adherend, a substrate such as a semiconductor chip individualized by dicing. Expanding tape used to increase the distance between wafers, transfer tape used to invert the front and back of adherends such as semiconductor chips, and temporary fixing used to temporarily fix an object to be inspected. Suitable for fixing sheets and the like.

The adherend of the pressure-sensitive adhesive sheet according to one aspect of the present invention is not particularly limited, and examples thereof include semiconductor chips, semiconductor wafers, compound semiconductors, semiconductor packages, electronic components, sapphire substrates, displays, and panel substrates.
When the expansion start temperature (t) of the heat-expandable particles is set to less than 125 ° C. as in the pressure-sensitive adhesive sheet of one aspect of the present invention, heat peeling is possible at a low temperature, so that heat of a semiconductor chip with DAF or the like can be obtained. It is suitable for temporarily fixing a variable adherend.
Further, when the expansion start temperature (t) of the heat-expandable particles is set to 50 ° C. or higher as in the pressure-sensitive adhesive sheet of one aspect of the present invention, thermal expansion due to temperature rise such as when grinding the adherend is performed. Since it can suppress the unintended expansion of the sex particles, it is suitable for use as a back grind sheet used in the process of grinding an adherend.

The heating temperature at which the pressure-sensitive adhesive sheet according to one aspect of the present invention is heat-peeled from the adherend is equal to or higher than the expansion start temperature (t) of the heat-expandable particles, and is preferably “a temperature higher than the expansion start temperature (t)”. , More preferably "expansion start temperature (t) + 2 ° C." or higher, further preferably "expansion start temperature (t) + 4 ° C." or higher, and even more preferably "expansion start temperature (t) + 5 ° C." or higher. Further, from the viewpoint of energy saving and suppressing the thermal change of the adherend at the time of heat peeling, it is preferably "expansion start temperature (t) + 50 ° C." or less, more preferably "expansion start temperature (t) + 40 ° C." or less. More preferably, it is "expansion start temperature (t) + 20 ° C." or less.
Further, the heating temperature at the time of heat peeling is preferably less than 125 ° C., more preferably 120 ° C. or lower, and further, within the range of the expansion start temperature (t) or higher, from the viewpoint of suppressing the thermal change of the adherend. It is preferably 115 ° C. or lower, more preferably 110 ° C. or lower, and even more preferably 105 ° C. or lower.

The heating method is not particularly limited as long as it can be heated to a temperature higher than the temperature at which the thermally expandable particles expand, and for example, an electric heater; dielectric heating; magnetic heating; near infrared rays, mid infrared rays, and far infrared rays. It is possible to appropriately use heating by electromagnetic waves such as infrared rays. The heating method may be any of a contact type heating method such as a heating roller and a heating press, and a non-contact type heating method such as an atmosphere heating device and infrared irradiation.

[Manufacturing method of semiconductor devices]
The present invention also provides a method for manufacturing a semiconductor device using the pressure-sensitive adhesive sheet according to one aspect of the present invention.
As one aspect of the method for manufacturing a semiconductor device of the present invention, the adhesive sheet of one aspect of the present invention is used as a temporary fixing sheet for performing at least one of processing and inspection of an adherend (hereinafter referred to as an aspect). , Also referred to as "a method for manufacturing a semiconductor device of the first aspect").
In addition, in this specification, a "semiconductor device" refers to a device in general that can function by utilizing semiconductor characteristics. For example, wafers with integrated circuits, thinned wafers with integrated circuits, chips with integrated circuits, thinned chips with integrated circuits, electronic components including these chips, and electronic components with the electronic components. Kind and the like.

<Manufacturing method of semiconductor device of the first aspect>
As a more specific aspect of the method for manufacturing a semiconductor device of the first aspect, a processing inspection object is attached to the pressure-sensitive adhesive sheet of one aspect of the present invention, and the processing inspection object is selected from processing and inspection. A method for manufacturing a semiconductor device, which includes a step of heating the pressure-sensitive adhesive sheet to the expansion start temperature (t) or higher after applying the above-mentioned one or more.
Examples of the processing inspection object include semiconductor chips, semiconductor wafers, compound semiconductors, semiconductor packages, electronic components, LED elements, sapphire substrates, displays, panel substrates, and the like.
The processing performed on the object to be inspected is not particularly limited, and examples thereof include grinding processing and individualization processing.
The inspection performed on the object to be processed is not particularly limited, but for example, defect inspection using an optical microscope or laser (for example, dust inspection, surface scratch inspection, wiring pattern inspection, etc.), visual surface inspection, etc. Can be mentioned.

In the method for manufacturing a semiconductor device of the first aspect, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet to which the processing inspection object is attached may be the pressure-sensitive adhesive layer (X1), and when the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, it is pressure-sensitive. It may be an agent layer (X2).
When the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, it is preferable that the object to be processed and inspected is attached to one of the pressure-sensitive adhesive layers and the support is attached to the other pressure-sensitive adhesive layer. By fixing the processing inspection object to the support via the adhesive sheet, vibration, misalignment, and damage to the fragile processing inspection object when performing at least one of processing and inspection. Etc. can be suppressed, and the processing accuracy and processing speed as well as the inspection accuracy and inspection speed can be improved. At this time, the support may be attached to the pressure-sensitive adhesive layer (X1) and the object to be processed and inspected may be attached to the pressure-sensitive adhesive layer (X2), or the object to be processed and inspected may be attached to the pressure-sensitive adhesive layer (X1). The support may be attached to the pressure-sensitive adhesive layer (X2).
When the support is attached to the pressure-sensitive adhesive layer (X1) and the object to be processed and inspected is attached to the pressure-sensitive adhesive layer (X2), the pressure-sensitive adhesive layer (X1) has excellent peelability after heat treatment. By attaching to, even if the support is made of a hard material, the adhesive sheet and the support can be heat-peeled without bending. Further, the composition of the pressure-sensitive adhesive layer (X2) may be appropriately selected according to the type of the object to be processed and inspected. For example, the pressure-sensitive adhesive layer (X2) may be a pressure-sensitive adhesive layer whose adhesive strength is reduced by irradiation with energy rays. Then, the object to be processed can be peeled off without being contaminated by the residue derived from the thermal expansion particles.
On the other hand, when the object to be processed and inspected is attached to the pressure-sensitive adhesive layer (X1) and the support is attached to the pressure-sensitive adhesive layer (X2), the object to be processed and inspected is an adhesive having excellent peelability after heat treatment. By being attached to the layer (X1), when heat peeling is performed after processing, it is not necessary to pick up the objects to be processed and inspected individually, and the objects can be easily peeled at once, so that the productivity of the semiconductor device is excellent. ..
Further, when the pressure-sensitive adhesive sheet according to one aspect of the present invention is used as a temporary fixing sheet for inspecting a processing inspection object as part of a manufacturing process, a plurality of processing inspections are performed on the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet. The inspection can be carried out with the object attached. After performing the inspection, for example, a part of the adhesive sheet to which the plurality of processing inspection objects are attached is locally heated to selectively select a specific processing inspection object attached to the portion. It can also be peeled off by heating. At this time, since the pressure-sensitive adhesive sheet according to one aspect of the present invention can be heat-peeled at a low temperature, it is excellent in workability and energy saving of the heat-peeling work, and the object to be processed and inspected is easily changed by heat. However, it is possible to suppress the thermal change of the processing inspection object due to heating at the time of heat peeling.

<Manufacturing method of semiconductor device of the second aspect>
As a method for manufacturing the semiconductor device of the second aspect, as the adhesive sheet of one aspect of the present invention, a double-sided adhesive sheet in which the expansion start temperature (t) of the heat-expandable particles is 50 ° C. or higher and lower than 125 ° C. is used, and the following steps are taken. Examples thereof include 1A to 3A, a manufacturing method including the following first separation step and the following second separation step (hereinafter, also referred to as “manufacturing method A”).
Step 1A: Attaching the object to be processed to the pressure-sensitive adhesive layer (X2) and attaching the support to the adhesive layer (X1) Step 2A: Select from grinding and individualizing the object to be processed. Step 3A: A step of sticking a thermosetting film on the surface of the processed object to be treated, which is opposite to the adhesive layer (X2). First separation step: The above. Step of separating the pressure-sensitive adhesive layer (X1) from the support by heating the pressure-sensitive adhesive sheet to the expansion start temperature (t) or more and less than 125 ° C. Second separation step: The pressure-sensitive adhesive layer (X2) and the processing target The process of separating things

Hereinafter, a method for manufacturing a semiconductor device including steps 1A to 3A, a first separation step, and a second separation step will be described with reference to the drawings. In the following description, an example in which a semiconductor wafer is used as a processing object will be mainly described, but the same applies to other processing objects. Examples of other processing objects include the same objects as described above as processing inspection objects.

(Step 1A)
Step 1A is a step of attaching the object to be processed to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet and attaching the support to the pressure-sensitive adhesive layer (X1).
FIG. 3 is a cross-sectional view illustrating a step of attaching the semiconductor wafer W to the adhesive layer (X2) of the adhesive sheet 2b and attaching the support 3 to the adhesive layer (X1).
The semiconductor wafer W is attached so that the surface W1 which is the circuit surface is on the adhesive layer (X2) side.
The semiconductor wafer W may be a silicon wafer, a wafer such as gallium arsenide, silicon carbide, sapphire, lithium tantalate, lithium niobate, gallium nitride, indium phosphorus, or a glass wafer.
The thickness of the semiconductor wafer W before grinding is usually 500 to 1000 μm.
The circuit included in the surface W1 of the semiconductor wafer W can be formed by, for example, a conventionally used general-purpose method such as an etching method or a lift-off method.

The material of the support 3 may be appropriately selected in consideration of required characteristics such as mechanical strength and heat resistance according to the type of the object to be processed, the content of processing, and the like.
Examples of the material of the support 3 include metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; epoxy resin, ABS resin, acrylic resin, engineering plastic, super engineering plastic, polyimide resin, polyamideimide resin and the like. Resin materials: Composite materials such as glass epoxy resin, and among these, SUS, glass, and silicon wafers are preferable.
Examples of the engineering plastic include nylon, polycarbonate (PC), polyethylene terephthalate (PET), and the like.
Examples of the super engineering plastic include polyphenylene sulfide (PPS), polyethersulfone (PES), and polyetheretherketone (PEEK).

The support 3 is preferably attached to the entire surface of the adhesive surface of the adhesive layer (X1). Therefore, the area of the surface of the support 3 on the side to be attached to the adhesive surface of the adhesive layer (X1) is preferably equal to or larger than the area of the adhesive surface of the adhesive layer (X1). Further, it is preferable that the surface of the support 3 on the side to be attached to the adhesive surface of the adhesive layer (X1) is flat.
The shape of the support 3 is not particularly limited, but is preferably plate-shaped.
The thickness of the support 3 may be appropriately selected in consideration of the required characteristics, but is preferably 20 μm or more and 50 mm or less, and more preferably 60 μm or more and 20 mm or less.

(Step 2A)
Step 2A is a step of performing one or more processes selected from a grinding process and an individualizing process on the object to be processed.
One or more processes selected from the grinding process and the individualizing process include, for example, a grinding process using a grinder or the like; an individualizing process by a blade dicing method, a laser dicing method, a stealth dicing (registered trademark) method; a blade tip. Grinding process and individualization process by dicing method, stealth tip dicing method; etc. can be mentioned.
Among these, individualization treatment by stealth dicing method, grinding treatment and individualization treatment by blade tip dicing method, grinding treatment and individualization treatment by stealth tip dicing method are preferable, and grinding treatment by blade tip dicing method. And individualization treatment, grinding treatment by stealth tip dicing method and individualization treatment are more preferable.

The stealth dicing method is a method in which a modified region is formed inside a semiconductor wafer by irradiation with laser light, and the semiconductor wafer is individualized using the modified region as a division starting point. The modified region formed on the semiconductor wafer is a portion brittled by multiphoton absorption, and the modified region is applied by applying stress in the direction in which the semiconductor wafer is parallel to the wafer surface and the wafer is expanded by expanding. The cracks extend toward the front surface and the back surface of the semiconductor wafer starting from the above, and are separated into semiconductor chips. That is, the modified region is formed along the dividing line when it is individualized.
The modified region is formed inside the semiconductor wafer by irradiation with a laser beam focused on the inside of the semiconductor wafer. The incident surface of the laser beam may be the front surface or the back surface of the semiconductor wafer. Further, the laser beam incident surface may be a surface to which the adhesive sheet is attached, in which case the laser beam is applied to the semiconductor wafer via the adhesive sheet.

The blade tip dicing method is also called the DBG method (Dicing Before Grinding). In the blade tip dicing method, a groove is formed in the semiconductor wafer in advance along the line to be divided at a depth shallower than the thickness, and then the semiconductor wafer is back-ground to be thin until the ground surface reaches at least the groove. It is a method of individualizing while making it. The groove reached by the ground surface becomes a notch penetrating the semiconductor wafer, and the semiconductor wafer is divided by the notch and separated into semiconductor chips. The pre-formed groove is usually provided on the surface (circuit surface) of the semiconductor wafer, and can be formed by dicing using, for example, a conventionally known wafer dicing apparatus provided with a dicing blade.

The stealth dicing method is also called the SDBG method (Stealth Dicing Before Grinding). Similar to the stealth dicing method, the stealth dicing method is a kind of method in which a modified region is formed inside the semiconductor wafer by irradiation with laser light, and the semiconductor wafer is individualized using the modified region as a division starting point. However, it differs from the stealth dicing method in that the semiconductor wafer is fragmented into semiconductor chips while thinning the semiconductor wafer by grinding. Specifically, while the semiconductor wafer having the modified region is back-ground to be thinned, the pressure applied to the semiconductor wafer at that time causes the modified region as a starting point to be directed toward the surface to be attached to the pressure-sensitive adhesive layer of the semiconductor wafer. The cracks are extended and the semiconductor wafer is separated into semiconductor chips.
The grinding thickness after the reformed region is formed may be the thickness reaching the reformed region, but even if it does not reach the reformed region strictly, it is ground to a position close to the reformed region. Then, it may be split by the processing pressure of a grinding wheel or the like.

When the semiconductor wafer W is individualized by the blade tip dicing method, it is preferable that a groove is formed in advance on the surface W1 of the semiconductor wafer W to be attached to the pressure-sensitive adhesive layer (X2) in step 1A.
On the other hand, when the semiconductor wafer W is individualized by the stealth tip dicing method, the semiconductor wafer W to be attached to the pressure-sensitive adhesive layer (X2) is irradiated with laser light in step 1A to form a modified region in advance. Alternatively, the semiconductor wafer W attached to the pressure-sensitive adhesive layer (X2) may be irradiated with a laser beam to form a modified region.

FIG. 4 shows a cross-sectional view illustrating a step of forming a plurality of reformed regions 5 on the semiconductor wafer W attached to the pressure-sensitive adhesive layer (X2) by using the laser light irradiation device 4.
The laser beam is irradiated from the back surface W2 side of the semiconductor wafer W, and a plurality of modified regions 5 are formed inside the semiconductor wafer W at substantially equal intervals.

In FIG. 5, a plurality of semiconductor chip CPs are shown while thinning the semiconductor wafer W by grinding the back surface W2 of the semiconductor wafer W on which the modified region 5 is formed by a grinder 6 and dividing the semiconductor wafer W starting from the modified region 5. A cross-sectional view illustrating the process of individualizing is shown.
In the semiconductor wafer W on which the modified region 5 is formed, for example, the back surface W2 of the semiconductor wafer W is ground in a state where the support 3 supporting the semiconductor wafer W is fixed on a fixed table such as a chuck table.

The thickness of the semiconductor chip CP after grinding is preferably 5 to 100 μm, more preferably 10 to 45 μm. Further, when the grinding process and the individualization process are performed by the stealth tip dicing method, the thickness of the semiconductor chip CP obtained by grinding can be easily set to 50 μm or less, more preferably 10 to 45 μm.
The size of the semiconductor chip CP after grinding in a plan view is preferably less than 600 mm ² , more preferably less than 400 mm ² , and even more preferably less than 300 mm ² . In addition, the plan view means to see in the thickness direction.
The shape of the semiconductor chip CP after fragmentation in a plan view may be a rectangular shape or an elongated shape such as a rectangle.
Since the pressure-sensitive adhesive sheet used in the method for manufacturing the semiconductor device of the second aspect has an expansion start temperature (t) of the thermally expandable particles of 50 ° C. or higher, it is thermally expandable due to a temperature rise such as when grinding is performed. It is possible to avoid a situation in which the particles unintentionally expand. Therefore, unintended separation and misalignment of the object to be processed are suppressed.

(Step 3A)
Step 3A is a step of attaching a thermosetting film to the surface of the processed object to be processed, which is opposite to the pressure-sensitive adhesive layer (X2).
FIG. 6 illustrates a step of attaching a thermosetting film 7 provided with a support sheet 8 to a surface of a plurality of semiconductor chip CPs obtained by performing the above treatment on a surface opposite to the pressure-sensitive adhesive layer (X2). A cross-sectional view is shown.

The thermosetting film 7 is a film having thermosetting property obtained by forming a resin composition containing at least a thermosetting resin, and is used as an adhesive when mounting a semiconductor chip CP on a substrate. The thermosetting film 7 may contain a curing agent for the thermosetting resin, a thermoplastic resin, an inorganic filler, a curing accelerator, and the like, if necessary.
As the thermosetting film 7, for example, a thermosetting film generally used as a die bonding film, a die attach film, or the like can be used.
The thickness of the thermosetting film 7 is not particularly limited, but is usually 1 to 200 μm, preferably 3 to 100 μm, and more preferably 5 to 50 μm.
The support sheet 8 may be any as long as it can support the thermosetting film 7. For example, the resin, metal, and the resin, metal, and the resin, metal, and the non-thermally expandable base material layer (Y2) of the pressure-sensitive adhesive sheet of one aspect of the present invention. Examples include paper materials.

Examples of the method of attaching the thermosetting film 7 to a plurality of semiconductor chip CPs include a method of laminating.
Laminating may be performed while heating or may be performed without heating. When the lamination is performed while heating, the heating temperature is preferably "a temperature lower than the expansion start temperature (t)" from the viewpoint of suppressing the expansion of the thermally expandable particles and suppressing the thermal change of the adherend. It is preferably "expansion start temperature (t) -5 ° C." or less, more preferably "expansion start temperature (t) -10 ° C." or less, and even more preferably "expansion start temperature (t) -15 ° C." or less.

(First separation process)
The first separation step is a step of heating the pressure-sensitive adhesive sheet to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C. to separate the pressure-sensitive adhesive layer (X1) from the support.
FIG. 7 is a cross-sectional view illustrating a step of heating the pressure-sensitive adhesive sheet 2b to separate the pressure-sensitive adhesive layer (X1) and the support 3.

The heating temperature in the first separation step is equal to or higher than the expansion start temperature (t) of the thermally expandable particles, and is preferably "a temperature higher than the expansion start temperature (t)", more preferably "expansion" in the range of 120 ° C. or lower. The start temperature (t) + 2 ° C. or higher, more preferably "expansion start temperature (t) + 4 ° C." or higher, and even more preferably "expansion start temperature (t) + 5 ° C." or higher. Further, the heating temperature in the first separation step is preferably "expansion start temperature (t) + 50 ° C." or less in the range of less than 125 ° C. from the viewpoint of energy saving and suppressing the thermal change of the adherend during heat peeling. , More preferably "expansion start temperature (t) + 40 ° C." or less, and even more preferably "expansion start temperature (t) + 20 ° C." or less.
The heating temperature in the first separation step is preferably 120 ° C. or lower, more preferably 115 ° C. or lower, still more preferably 115 ° C. or lower, within the range of the expansion start temperature (t) or higher, from the viewpoint of suppressing the thermal change of the adherend. It is 110 ° C. or lower, more preferably 105 ° C. or lower.

(Second separation step)
The second separation step is a step of separating the pressure-sensitive adhesive layer (X2) from the object to be processed.
FIG. 8 shows a cross-sectional view illustrating a step of separating the pressure-sensitive adhesive layer (X2) and the plurality of semiconductor chip CPs.
The method for separating the pressure-sensitive adhesive layer (X2) and the plurality of semiconductor chip CPs may be appropriately selected according to the type of the pressure-sensitive adhesive layer (X2). For example, when the pressure-sensitive adhesive layer (X2) is a pressure-sensitive adhesive layer whose adhesive strength is reduced by irradiation with energy rays, the pressure-sensitive adhesive layer (X2) is irradiated with energy rays to reduce the pressure-sensitive adhesive strength. It should be separated.

Through the steps 1A to 3A, the first separation step, and the second separation step, a plurality of semiconductor chip CPs attached on the thermosetting film 7 are obtained.
Next, it is preferable to divide the thermosetting film 7 to which the plurality of semiconductor chip CPs are attached into the same shape as the semiconductor chip CP to obtain the semiconductor chip CP with the thermosetting film 7. As a method for dividing the thermosetting film 7, for example, a method such as laser dicing with laser light, expanding, or fusing can be applied.
FIG. 9 shows a semiconductor chip CP with a thermosetting film 7 divided into the same shape as the semiconductor chip CP.

The semiconductor chip CP with the thermosetting film 7 further includes an expanding step of widening the distance between the semiconductor chip CPs, a rearrangement step of arranging a plurality of semiconductor chip CPs having a wide distance, and a plurality of semiconductor chip CPs, if necessary. After an appropriate inversion step of inverting the front and back of the above, the thermosetting film 7 is attached (diatached) to the substrate from the side. After that, the semiconductor chip and the substrate can be fixed by thermosetting the thermosetting film.

The method for manufacturing a semiconductor device according to one aspect of the present invention may not include step 3A in the manufacturing method A. When the step 3A is not included, the first separation step may be a step of heating the pressure-sensitive adhesive sheet to the expansion start temperature (t) or higher to separate the pressure-sensitive adhesive layer (X1) from the support. ..

The method for manufacturing the semiconductor device of the second aspect may be a manufacturing method including the following steps 1B to 3B, the following first separation step, and the following second separation step (hereinafter, also referred to as “manufacturing method B”). ..
Step 1B: A process of attaching the object to be processed to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet, and attaching a support to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet Step 2B: The process of attaching the support to the object to be processed. Step of applying one or more treatments selected from grinding treatment and individualization treatment Step 3B: Thermosetting is applied to the surface of the processed object to which the treatment has been performed, which is opposite to the adhesive layer (X1). Step of attaching the thermosetting film to be provided First separation step: The pressure-sensitive adhesive sheet is heated to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C. to separate the pressure-sensitive adhesive layer (X1) from the object to be processed. Step Second separation step: A step of separating the pressure-sensitive adhesive layer (X2) from the support.

Steps 1B to 3B are described by replacing the pressure-sensitive adhesive layer (X1) with the pressure-sensitive adhesive layer (X2) and the pressure-sensitive adhesive layer (X2) with the pressure-sensitive adhesive layer (X1) in the description of steps 1A to 3A. ..

The first separation step is a step of heating the pressure-sensitive adhesive sheet to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C. to separate the pressure-sensitive adhesive layer (X1) from the object to be processed.
The heating conditions such as the heating temperature of the pressure-sensitive adhesive sheet in the first separation step are the same as those described in the manufacturing method A.
By the first separation step, a plurality of semiconductor chips attached on the thermosetting film are obtained. Then, as in the case of the manufacturing method A described above, the thermosetting film is divided to obtain a semiconductor chip with a thermosetting film.

The second separation step is a step of separating the pressure-sensitive adhesive layer (X2) from the support.
The method for separating the pressure-sensitive adhesive layer (X2) and the support may be appropriately selected according to the type of the pressure-sensitive adhesive layer (X2). For example, when the pressure-sensitive adhesive layer (X2) is a pressure-sensitive adhesive layer whose adhesive strength is reduced by irradiation with energy rays, the pressure-sensitive adhesive layer (X2) is irradiated with energy rays to reduce the pressure-sensitive adhesive strength. It should be separated.

The method for manufacturing a semiconductor device according to one aspect of the present invention may not include step 3B in the manufacturing method B. When step 3B is not included, the first separation step is a step of heating the pressure-sensitive adhesive sheet to the expansion start temperature (t) or higher to separate the pressure-sensitive adhesive layer (X1) from the object to be processed. Good.

<Manufacturing method of semiconductor device of another aspect>
The method for manufacturing a semiconductor device of the present invention is not limited to the method for manufacturing a semiconductor device according to the first aspect described above, and may be a method for manufacturing a semiconductor device according to another aspect from the first aspect.

As another example of the method for manufacturing a semiconductor device of another aspect, there is a method of separating an object to be processed attached to another sheet from the other sheet by using the adhesive sheet of one aspect of the present invention. Can be mentioned.
For example, a plurality of semiconductor chips that are spaced apart on the expanding tape are attached to the adhesive surface of the expanding tape, but the work of picking up these chips one by one is complicated. According to the method for manufacturing a semiconductor device according to one aspect of the present invention, the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet according to one aspect of the present invention is attached to the exposed surface of a plurality of semiconductor chips attached on the expanding tape, and then. By peeling the expanding tape from the plurality of semiconductor chips, the plurality of semiconductor chips can be separated from the expanding tape at once.
Through the above steps, a plurality of semiconductor chips attached on the pressure-sensitive adhesive sheet according to one aspect of the present invention can be obtained. The plurality of semiconductor chips can be easily separated by subsequently heating the pressure-sensitive adhesive sheet to a temperature (t) or higher at which the heat-expandable particles start to expand. At this time, since the pressure-sensitive adhesive sheet according to one aspect of the present invention can be heat-peeled at a low temperature, it is excellent in workability and energy saving of heat-peeling work, and even if the object to be processed is easily thermally changed. , It is possible to suppress the thermal change of the adherend due to heating at the time of heat peeling.
The plurality of separated semiconductor chips may be transferred to another pressure-sensitive adhesive sheet, or may be subjected to a rearrangement step of aligning the plurality of semiconductor chips after being separated once.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples. The physical property values in the following synthesis examples, production examples, and examples are values measured by the following methods.

[Mass average molecular weight (Mw)]
It was measured under the following conditions using a gel permeation chromatograph device (manufactured by Tosoh Corporation, product name "HLC-8020"), and the value measured in terms of standard polystyrene was used.
(Measurement condition)
-Column: "TSK guard volume HXL-L""TSK gel G2500HXL""TSK gel G2000HXL""TSK gel G1000HXL" (all manufactured by Tosoh Corporation) are connected in sequence.-Column temperature: 40 ° C.
-Development solvent: tetrahydrofuran-Flow velocity: 1.0 mL / min

[Thickness of each layer]
The measurement was performed using a constant pressure thickness measuring instrument (model number: "PG-02J", standard: JIS K6783, Z1702, Z1709 compliant) manufactured by Teclock Co., Ltd.

[Average particle size of thermally expandable particles (D ₅₀ ), 90% particle size (D ₉₀ )]
The particle distribution of the thermally expandable particles before expansion at 23 ° C. was measured using a laser diffraction type particle size distribution measuring device (for example, manufactured by Malvern, product name “Master Sizar 3000”).
Then, the particle diameters corresponding to the cumulative volume frequencies of 50% and 90% calculated from the smaller particle diameter of the particle distribution are set to "average particle diameter of thermally expandable particles (D ₅₀ )" and "thermally expandable particles", respectively. 90% particle size (D ₉₀ ) ”.

[Storage modulus of substrate E']
A dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name) using a heat-expandable base material layer (Y1) and a non-heat-expandable base material layer (Y2) cut into a length of 5 mm and a width of 30 mm as test samples. Using "DMAQ800"), the storage elastic modulus E'at a predetermined temperature was measured under the conditions of a test start temperature of 0 ° C., a test end temperature of 200 ° C., a temperature rise rate of 3 ° C./min, a frequency of 1 Hz, and an amplitude of 20 μm. ..

[Young's modulus of the substrate at 23 ° C]
The Young's modulus of the heat-expandable base material layer (Y1) and the non-heat-expandable base material layer (Y2) was measured at a test speed of 200 mm / min according to JISK-7127 (1999).

In the following production examples, the details of the adhesive resin, additives, heat-expandable particles, and release material used to form each layer are as follows.

<Adhesive resin>
-Acrylic copolymer (A1): n-butyl acrylate (BA) / methyl methacrylate (MMA) / acrylic acid (AA) / 2-hydroxyethyl acrylate (HEA) = 86/8/1/5 (mass ratio) A solution containing an acrylic copolymer of Mw 600,000 having a structural unit derived from a raw material monomer composed of, diluting solvent: ethyl acetate, solid content concentration: 40% by mass.
Acrylic copolymer (A2): Raw material monomer composed of 2-ethylhexyl acrylate (2EHA) / acrylic acid (AA) / 2-hydroxyethyl acrylate (HEA) = 92.8 / 0.2 / 7 (mass ratio) Solution containing an acrylic copolymer of Mw 600,000 having a structural unit derived from, diluting solvent: ethyl acetate, solid content concentration: 35% by mass
-Acrylic copolymer (A3): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "Corponil N-9177", adhesive solution containing acrylic copolymer-Acrylic copolymer (A4): 2- An acrylic copolymer of Mw60 having a structural unit derived from a raw material monomer composed of ethylhexyl acrylate (2EHA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) = 60/30/10 (mass ratio). Containing solution, diluting polymer: ethyl acetate, solid content concentration: 40% by mass
-Acrylic copolymer (A5): A composition derived from a raw material monomer composed of n-butyl acrylate (BA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) = 52/20/28 (mass ratio). Acrylic copolymer having a unit was reacted with 2-methacryloyloxyethyl isocyanate (MOI) so that the addition rate with respect to all the hydroxyl groups in the acrylic copolymer was 80% based on the number of moles. Solution containing energy ray-curable acrylic copolymer, diluting solvent: ethyl acetate, solid content concentration: 35% by mass

<Additives>
-Isocyanate-based cross-linking agent (i): manufactured by Tosoh Corporation, product name "Coronate HX", solution containing isocyanurate-type modified hexamethylene diisocyanate, solid content concentration: 75% by mass
-Isocyanate-based cross-linking agent (ii): manufactured by Tosoh Corporation, product name "Coronate L", solution containing trimethylolpropane-modified tolylene diisocyanate, solid content concentration: 75% by mass
-Energy ray-curable compound: manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "Shikou UT-4332", polyfunctional urethane acrylate-photopolymerization initiator (i): bis (2,4,6-trimethylbenzoyl) phenylphos Finoxide / Photopolymerization Initiator (ii): 1-Hydroxycyclohexylphenylketone / phthalocyanine pigment

<Thermal expandable particles>
-Thermal expandable particles: manufactured by AkzoNobel, product name "Expancel (registered trademark) 031-40" (DU type), expansion start temperature (t) = 88 ° C., average particle diameter (D ₅₀ ) = 12.6 μm, 90 % Particle diameter (D ₉₀ ) = 26.2 μm

<Release material>
-Heavy release film: manufactured by Lintec Corporation, product name "SP-PET382150", polyethylene terephthalate (PET) film with a release agent layer formed from a silicone-based release agent on one side, thickness: 38 μm
-Light release film: manufactured by Lintec Corporation, product name "SP-PET381031", PET film with a release agent layer formed from a silicone-based release agent on one side, thickness: 38 μm

Production Example 1-1: Formation of Adhesive Layer (X1-A1) 0.74 parts by mass (solid content ratio) of the isocyanate-based cross-linking agent (i) is added to 100 parts by mass of the solid content of the acrylic copolymer (A1). A pressure-sensitive adhesive composition (x-1-A1) having a solid content concentration (active ingredient concentration) of 25% by mass was prepared by blending, diluting with toluene, and stirring uniformly.
Then, the prepared pressure-sensitive adhesive composition (x-1-A1) is applied onto the peeling surface of the light release film to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to have a thickness of 5 μm. Adhesive layer (X1-A1) was formed.

Production Example 1-2: Formation of Adhesive Layer (X1-A2) The acrylic copolymer (A1) is changed to the acrylic copolymer (A2), and the blending amount of the isocyanate-based cross-linking agent (i) is the same. The solid content concentration (effective) by the same method as in Production Example 1-1 except that the solid content of the acrylic copolymer (A2) was changed to 4.76 parts by mass (solid content ratio) with respect to 100 parts by mass. A pressure-sensitive adhesive composition (x-1-A2) having a component concentration of 25% by mass was prepared to form a pressure-sensitive adhesive layer (X1-A2) having a thickness of 5 μm.

Production Example 1-3: Formation of Adhesive Layer (X1-A3) The acrylic copolymer (A1) is changed to the acrylic copolymer (A3), and the blending amount of the isocyanate-based cross-linking agent (i) is the same. The solid content concentration (effective) by the same method as in Production Example 1-1 except that the solid content of the acrylic copolymer (A3) was changed to 3.85 parts by mass (solid content ratio) with respect to 100 parts by mass. A pressure-sensitive adhesive composition (x-1-A3) having a component concentration of 25% by mass was prepared, and a pressure-sensitive adhesive layer (X1-A3) having a thickness of 5 μm was formed.

Production Example 1-4: Formation of Adhesive Layer (X1-A4) The acrylic copolymer (A1) is changed to the acrylic copolymer (A4), and the blending amount of the isocyanate-based cross-linking agent (i) is the same. The solid content concentration (effective) by the same method as in Production Example 1-1 except that the solid content of the acrylic copolymer (A4) was changed to 15.8 parts by mass (solid content ratio) with respect to 100 parts by mass. A pressure-sensitive adhesive composition (x-1-A4) having a component concentration of 25% by mass was prepared, and a pressure-sensitive adhesive layer (X1-A4) having a thickness of 5 μm was formed.

Production Example 2: Formation of Adhesive Layer (X2) An energy ray-curable compound is added to 100 parts by mass of the solid content of the acrylic copolymer (A5), which is an energy ray-curable adhesive resin, by 4.2 parts by mass. 0.74 parts by mass of the isocyanate-based cross-linking agent (ii) and 1 part by mass of the photopolymerization initiator (i) are mixed, diluted with toluene, and uniformly stirred to obtain a solid content concentration (active ingredient concentration) of 30% by mass. The pressure-sensitive adhesive composition (x-2-A5) of the above was prepared.
Then, the prepared pressure-sensitive adhesive composition (x-2-A5) is applied onto the peeling surface of the heavy-release film to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to have a thickness of 20 μm. Adhesive layer (X2-A5) was formed.

Production Example 3: Formation of a base material laminate in which a heat-expandable base material layer (Y1) and a non-heat-expandable base material layer (Y2) are laminated (1) Preparation of a solvent-free resin composition (y-1a) 2-Hydroxyethyl acrylate is reacted with the terminal isocyanate urethane prepolymer obtained by reacting the ester-type diol with isophorone diisocyanate (IPDI) to obtain a bifunctional acrylic urethane-based oligomer having a mass average molecular weight (Mw) of 5000. Obtained.
Then, 40% by mass (solid content ratio) of the acrylic urethane-based oligomer synthesized above, 40% by mass (solid content ratio) of isobornyl acrylate (IBXA) and phenylhydroxypropyl acrylate (HPPA) as energy ray-polymerizable monomers. ) 20 parts by mass (solid content ratio) is blended, and 2.0 parts by mass (solid) of the photopolymerization initiator (ii) is further added to the total amount (100 parts by mass) of the acrylic urethane-based oligomer and the energy ray-polymerizable monomer. A phthalocyanine-based pigment (0.2 parts by mass (solid content ratio)) was blended as an additive to prepare an energy ray-curable composition.
Then, the heat-expandable particles (i) were blended with the energy ray-curable composition to prepare a solvent-free resin composition (y-1a) containing no solvent.
The content of the heat-expandable particles (i) was 20% by mass with respect to the total amount (100% by mass) of the solvent-free resin composition (y-1a).
(2) Formation of a base material laminate in which a heat-expandable base material layer (Y1) and a non-heat-expandable base material layer (Y2) are laminated As a non-heat-expandable base material layer (Y2), PET film (Toyo Boseki Co., Ltd.) A solvent-free resin composition (y-1a) was applied to one side of the PET film to form a coating film using a company-made product name “Cosmo Shine A4300”, thickness: 50 μm).
Then, using an ultraviolet irradiation device (manufactured by Eye Graphics Co., Ltd., product name "ECS-401GX") and a high-pressure mercury lamp (manufactured by Eye Graphics Co., Ltd., product name "H04-L41"), an illuminance of 160 mW / cm ² The coating film is cured by irradiating with ultraviolet rays under the condition of a light amount of 500 mJ / cm ² , and a heat-expandable base layer (Y1) having a thickness of 100 μm is placed on a PET film as a non-heat-expandable base layer (Y2). Formed. The above-mentioned illuminance and light intensity at the time of ultraviolet irradiation are values measured using an illuminance / light intensity meter (manufactured by EIT, product name "UV Power Pack II").

Incidentally, the storage elastic modulus E at 23 ° C. of the heat-expandable base layer (Y1) 'was 5.0 × ¹⁰ 8 Pa.
The Young's modulus of the heat-expandable substrate layer (Y1) at 23 ° C. was 330 MPa, and the Young's modulus of the non-thermally expandable substrate layer (Y2) at 23 ° C. was 2000 MPa.

Example 1
The adhesive surface of the pressure-sensitive adhesive layer (X1-A1) formed in Production Example 1-1 and the surface of the heat-expandable base material layer (Y1) of the base material laminate formed in Production Example 3 were bonded together. Next, the adhesive surface of the pressure-sensitive adhesive layer (X2-A5) formed in Production Example 2 and the PET film surface of the base material laminate were bonded together.
As a result, an adhesive sheet having the following structure was produced.
<Light release film> / <Adhesive layer (X1-A1), thickness: 5 μm> / <heat-expandable base layer (Y1), thickness: 100 μm> / <non-heat-expandable base layer (Y2) , Thickness: 50 μm> / <Adhesive layer (X2-A5), Thickness: 20 μm> / <Heavy release film>

Example 2
A pressure-sensitive adhesive sheet having the following constitution was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (X1-A2) formed in Production Example 1-2 was used.
<Light release film> / <Adhesive layer (X1-A2), thickness: 5 μm> / <thermally expandable base material layer (Y1), thickness: 100 μm> / <non-thermally expandable base material layer (Y2) , Thickness: 50 μm> / <Adhesive layer (X2-A5), Thickness: 20 μm> / <Heavy release film>

Comparative Example 1
A pressure-sensitive adhesive sheet having the following constitution was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (X1-A3) formed in Production Example 1-3 was used.
<Light release film> / <Adhesive layer (X1-A3), thickness: 5 μm> / <heat-expandable base layer (Y1), thickness: 100 μm> / <non-heat-expandable base layer (Y2) , Thickness: 50 μm> / <Adhesive layer (X2-A5), Thickness: 20 μm> / <Heavy release film>

Comparative Example 2
A pressure-sensitive adhesive sheet having the following constitution was produced in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (X1-A4) formed in Production Example 1-4 was used.
<Light release film> / <Adhesive layer (X1-A4), thickness: 5 μm> / <thermally expandable base material layer (Y1), thickness: 100 μm> / <non-thermally expandable base material layer (Y2) , Thickness: 50 μm> / <Adhesive layer (X2-A5), Thickness: 20 μm> / <Heavy release film>

[Evaluation of initial adhesive strength of adhesive layer (X1)]
The light release film of the adhesive sheet produced in Examples 1 and 2 and Comparative Examples 1 and 2 was removed, and the exposed adhesive surface of the adhesive layer (X1) was weighed on a soda lime glass plate as an adherend. A test sample was prepared by reciprocating once with a 2 kg roller, attaching the film, and then allowing the film to stand for 20 minutes in an environment of 23 ° C. and 50% RH (relative humidity).
Then, using a universal tensile tester (manufactured by Orientec Co., Ltd., model number: Tensilon RTC-1210A), pull 180 ° based on JIS Z0237: 2000 in an environment of 23 ° C and 50% RH (relative humidity). The adhesive strength of the test sample at 23 ° C. was measured at a tensile speed of 300 mm / min by the peeling method.
The initial adhesive strength of the test sample was measured twice, and the average value was calculated. In addition, any of the pressure-sensitive adhesive layers (X1-A1, X1-A2, X1-A3, and X1-A4) of the pressure-sensitive adhesive sheets in Examples 1 and 2 and Comparative Examples 1 and 2 are soda lime glass as an adherend. It was confirmed that the board was attached to a level where it would not come off under its own weight.

[Evaluation of self-peeling property]
Two 30 mm × 30 mm × 1.1 mm soda lime glass plates were prepared. Hereinafter, the two soda lime glass plates are referred to as "glass plate G1" and "glass plate G2", respectively.
The pressure-sensitive adhesive sheet produced in Example 1-2 and Comparative Example 1-2 was cut into 30 mm × 30 mm, and the pressure-sensitive adhesive layer (X1-A1, X1-) on the heat-expandable base material layer (Y1) side of the cut pressure-sensitive adhesive sheet was cut. The light release film was removed from A2, X1-A3, and X1-A4), and the glass plate G1 was attached. Next, after removing the heavy release film from the pressure-sensitive adhesive layer (X2-A5) on the non-thermally expandable base material layer (Y2) side and attaching the glass plate G2, a vacuum laminator (manufactured by Nikko Materials Co., Ltd.) A test sample was prepared by pressing at 60 ° C. under the condition of 0.2 MPa for 30 seconds under the name “V-130”).
Then, the test sample was placed on a hot plate and heated at 100 ° C., which is equal to or higher than the expansion start temperature of the heat-expandable particles, for 5 minutes. The test sample was placed on the hot plate so that the glass plate G2 side was on the side in contact with the hot plate and the adhesive sheet side was on the side not in contact with the hot plate.
After heating at 100 ° C. for 5 minutes, the peeling state of the glass plate G1 from the adhesive sheet was visually confirmed, and the self-peeling property was evaluated according to the following criteria.
A: The entire surface of the glass plate G1 is peeled off from the adhesive sheet.
F: Part or all of the glass plate G1 is not peeled from the adhesive sheet.

[Evaluation of Young's modulus of adhesive layer (X1)]
(1) Preparation of evaluation sample A 400 μm-thick adhesive layer (X1-A1) to which a PET-based release film (manufactured by Lintec Corporation, product name “SP-PET38 1031”, thickness: 38 μm) is attached to both sides. ), The pressure-sensitive adhesive layer (X1-A2), the pressure-sensitive adhesive layer (X1-A3), and the pressure-sensitive adhesive layer (X1-A4) were prepared.
(2) Tensile test The prepared evaluation sample was cut out to a size of 15 mm × 140 mm, and labels for film tension were attached to both ends 20 mm to prepare a dumbbell-shaped sample of 15 mm × 100 mm. Then, the Young's modulus when tensioning was performed at a speed of 200 mm / min with an Autograph AG-100N XPrus manufactured by Shimadzu Corporation was measured.

The evaluation results are shown in Table 1.

From Table 1, in the pressure-sensitive adhesive sheets of Examples 1 and 2, the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is 5.0 MPa or less, and the Young's modulus of the non-thermally expandable base material layer (Y2) at 23 ° C. Since the coefficient is higher than the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C., it can be seen that the self-peeling property is good. On the other hand, in the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2, since the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is larger than 5.0 MPa, it can be seen that the self-peeling property is deteriorated.

1a, 1b, 2a,

2b Adhesive sheet

10, 10a, 10b Release material 3 Support 4 Laser light irradiation device 5 Modified area 6 Grinder 7 Thermocurable film 8 Support sheet W Semiconductor wafer W1 Circuit surface of semiconductor wafer and semiconductor chip Back side of W2 semiconductor wafer and semiconductor chip CP semiconductor chip

Claims

The pressure-sensitive adhesive layer (X1), the heat-expandable base material layer (Y1) containing the heat-expandable particles, and the non-heat-expandable base material layer (Y2) have a laminated structure in which they are arranged in this order.
The Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C. is 5.0 MPa or less.
A pressure-sensitive adhesive sheet in which the Young's modulus of the non-thermally expandable base material layer (Y2) at 23 ° C. is higher than the Young's modulus of the pressure-sensitive adhesive layer (X1) at 23 ° C.
The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer (X1) has a thickness of 3 to 10 μm at 23 ° C.
The product of the Young's modulus (unit: MPa) of the pressure-sensitive adhesive layer (X1) at 23 ° C. and the thickness (unit: μm) of the pressure-sensitive adhesive layer (X1) at 23 ° C. is 0.3 to 50. , The adhesive sheet according to claim 1 or 2.
The one according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer (X1) is a layer formed from a pressure-sensitive adhesive composition (x-1) containing an acrylic resin and an isocyanate-based cross-linking agent. Adhesive sheet.
The pressure-sensitive adhesive sheet according to claim 4, wherein the isocyanate-based cross-linking agent contains an isocyanurate-type modified product having an isocyanurate ring.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the non-thermally expandable base material layer (Y2) has a Young's modulus of 700 MPa or more at 23 ° C.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the non-thermally expandable base material layer (Y2) is a polyethylene terephthalate film.
Claims 1 to 7, further comprising an adhesive layer (X2) on a surface of the non-thermally expandable base material layer (Y2) opposite to the laminated surface of the heat expandable base material layer (Y1). The adhesive sheet according to any one item.
The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the thermally expandable particles have an expansion start temperature (t) of 50 ° C. or higher and lower than 125 ° C.
The adhesive sheet according to claim 8, wherein the thermally expandable particles have an expansion start temperature (t) of 50 ° C. or higher and lower than 125 ° C.
The pressure-sensitive adhesive sheet according to claim 10, wherein the pressure-sensitive adhesive layer (X2) is a pressure-sensitive adhesive layer that is cured by irradiating with energy rays to reduce the adhesive strength.
The object to be processed and inspected is attached to the adhesive sheet according to any one of claims 1 to 11.
A step of heating the pressure-sensitive adhesive sheet to a temperature equal to or higher than the expansion start temperature (t) of the heat-expandable particles contained in the pressure-sensitive adhesive sheet after applying one or more selected from processing and inspection to the processing inspection object. A method for manufacturing a semiconductor device, including.
A method for manufacturing a semiconductor device, which comprises the following steps 1A to 3A, the following first separation step, and the following second separation step using the pressure-sensitive adhesive sheet according to claim 10 or 11.
Step 1A: A process of attaching the object to be processed to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet, and attaching a support to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet Step 2A: For the object to be processed Step 3A: A process of performing one or more treatments selected from a grinding treatment and an individualization treatment Step 3A: A heat-curable surface of the processed object to be processed, which is opposite to the adhesive layer (X2). First separation step: The pressure-sensitive adhesive sheet is heated to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C. to separate the pressure-sensitive adhesive layer (X1) from the support. Second separation step: A step of separating the pressure-sensitive adhesive layer (X2) from the object to be processed.
A method for manufacturing a semiconductor device, which comprises the following steps 1B to 3B, the following first separation step, and the following second separation step using the pressure-sensitive adhesive sheet according to claim 10 or 11.
Step 1B: A process of attaching the object to be processed to the pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet, and attaching a support to the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet Step 2B: For the object to be processed Step 3B: A process of performing one or more treatments selected from the grinding treatment and the individualization treatment Step 3B: The surface of the processed object to which the treatment has been subjected to the heat curable on the surface opposite to the adhesive layer (X1). First separation step: The pressure-sensitive adhesive sheet is heated to a temperature equal to or higher than the expansion start temperature (t) and lower than 125 ° C., and the pressure-sensitive adhesive layer (X1) and the object to be processed are separated from each other. Separation step Second separation step: A step of separating the pressure-sensitive adhesive layer (X2) and the support.
Using the adhesive sheet according to claim 11,
The method for manufacturing a semiconductor device according to claim 13 or 14, wherein the second separation step includes a step of curing the pressure-sensitive adhesive layer (X2) by irradiating the pressure-sensitive adhesive layer (X2) with energy rays.