WO2023054318A1

WO2023054318A1 - Method for producing semiconductor device

Info

Publication number: WO2023054318A1
Application number: PCT/JP2022/035847
Authority: WO
Inventors: 康喜中石; 智則篠田; 拓根本; 桜子田村; 章生加太; 智史川田
Original assignee: リンテック株式会社
Priority date: 2021-09-29
Filing date: 2022-09-27
Publication date: 2023-04-06
Also published as: JPWO2023054318A1; TW202333211A

Abstract

The present invention relates to a method for producing a semiconductor device, the method using a double-sided adhesive sheet which has at least an adhesive layer (X1) that serves as the one surface-side outer layer and an adhesive layer (X2) that serves as the other surface-side outer layer, wherein the adhesive layer (X2) is an energy ray-curable adhesive layer and at least one of the layers other than the adhesive layer (X2) is a thermally expandable layer that contains thermally expandable particles. This method for producing a semiconductor device comprises specific steps 1 to 4 in this order, while comprising an energy ray irradiation step at a specific timing.

Description

Semiconductor device manufacturing method

The present invention relates to a method of manufacturing a semiconductor device.

In the manufacturing process of semiconductor devices, semiconductor wafers are processed into semiconductor chips through a grinding process to reduce the thickness by grinding and a singulation process to cut and separate into individual pieces. At this time, the semiconductor wafer is subjected to a predetermined processing while being temporarily fixed to the temporary fixing sheet. After the semiconductor chips obtained by performing the predetermined processing are separated from the temporary fixing sheet, if necessary, an expanding step is performed to widen the gap between the semiconductor chips, and a re-arrangement of a plurality of semiconductor chips with widened gaps is performed. After an arrangement process, a reversing process for reversing 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-peelable pressure-sensitive adhesive sheet for temporary fixing when cutting an electronic component, in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres is provided on at least one side of a base material. . In the same document, the heat-peelable pressure-sensitive adhesive sheet can secure a contact area of a predetermined size with respect to the adherend when cutting electronic parts, and thus exhibits adhesiveness capable of preventing adhesion defects such as chip flying. On the other hand, it is described that if the heat-expandable microspheres are expanded by heating after use, the contact area with the adherend can be reduced, so that they can be easily peeled off.

Japanese Patent No. 3594853

When the temporary fixing sheet is used for processing an object, one surface of the temporary fixing sheet is attached to the object and the other surface is attached to a support, and then subjected to a predetermined process. . In this case, a double-sided pressure-sensitive adhesive sheet having pressure-sensitive adhesive layers on both sides is used as the temporary fixing sheet.
Here, an object to be processed is attached to the adhesive layer on one side of the double-sided adhesive sheet, and the adhesive layer on the other side is a heat-peelable adhesive layer whose adhesive strength is reduced by the action of thermal expansion. However, when the surface on which the heat-peelable pressure-sensitive adhesive layer is provided is attached to a support, there is a problem that the object to be processed is sometimes difficult to separate from the surface of the double-sided pressure-sensitive adhesive sheet attached to the object.

The present invention has been made in view of the above-mentioned problems, and an object to be processed is attached to a pressure-sensitive adhesive layer, which is an outer layer on one side of a double-sided pressure-sensitive adhesive sheet. Provided is a method for manufacturing a semiconductor device in which an object to be processed is processed by attaching a support to a layer, and the object to be processed and the support can be easily separated from the double-sided adhesive sheet after processing. With the goal.

The present inventors have proposed a double-sided pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer as the outer layer on one side is a heat-peelable pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer as the outer layer on the other side is an energy ray-curable pressure-sensitive adhesive. Manufacture of a semiconductor device in which a double-sided adhesive sheet is used as a layer, an object to be processed is attached to the energy ray-curable adhesive layer, a support is attached to the heat-peelable adhesive layer, and the object is processed. In the method, the inventors have found that the above problems can be solved by performing the energy ray irradiation step for curing the energy ray-curable pressure-sensitive adhesive layer at a specific time, and have completed the present invention.

That is, the present invention relates to the following [1] to [12].
[1] having at least an adhesive layer (X1) as an outer layer on one side and an adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
Using a double-sided pressure-sensitive adhesive sheet in which at least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method of manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
energy ray irradiation step: a step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2) without expanding the thermally expandable particles [2] At least a pressure-sensitive adhesive layer (X1) as an outer layer on the surface side and a pressure-sensitive adhesive layer (X2) as an outer layer on the other surface side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
Using a double-sided pressure-sensitive adhesive sheet in which at least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method of manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy beam irradiation step: the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet so that the temperature of the thermally expandable layer does not exceed a temperature lower than the expansion start temperature (t) of the thermally expandable particles by 5°C. The step of curing the pressure-sensitive adhesive layer (X2) by irradiating energy rays to [3] the pressure-sensitive adhesive layer (X1) as an outer layer on one side and the pressure-sensitive adhesive layer (X2) as an outer layer on the other side ) is a double-sided pressure-sensitive adhesive sheet having at least
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
At least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
A laminate obtained by laminating a glass plate made of soda lime glass and having a thickness of 1.1 mm on the adhesive layer (X2) of the double-sided adhesive sheet was placed at a temperature of 22°C + the expansion start temperature (t) of the thermally expandable particles. Using a double-sided adhesive sheet having a total light transmittance (T _A ) at a wavelength of 380 nm in the thickness direction of the laminate (L _A ) for measuring the total light transmittance obtained by heating for 1 minute at a temperature of less than 20%,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method for manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy ray irradiation step: Step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with energy rays to cure the pressure-sensitive adhesive layer (X2) [4] Applying the energy ray irradiation step to the double-sided pressure-sensitive adhesive sheet On the other hand, the method for manufacturing a semiconductor device according to any one of [1] to [3], wherein the method is performed while performing a cooling treatment.
[5] The above [1] to [4], wherein the energy beam irradiation step is a step performed in a chamber filled with gas and satisfies the following requirements (I) or (II): A method for manufacturing a semiconductor device according to any one of the above.
(I) The energy beam irradiation step is a step of replacing at least part of the gas filled in the chamber with gas supplied from outside the chamber during the energy beam irradiation step.
(II) The energy ray irradiation step further repeats a cycle of irradiating one double-sided pressure-sensitive adhesive sheet with an energy ray and then starting irradiation of another double-sided pressure-sensitive adhesive sheet with an energy ray to obtain a plurality of double-sided pressure-sensitive adhesive sheets. A step of sequentially irradiating the adhesive sheet with energy rays,
The repeated cycle is
In at least one cycle, after irradiating the one double-sided pressure-sensitive adhesive sheet with an energy ray and before starting irradiation of the energy ray on the other double-sided pressure-sensitive adhesive sheet, the gas filled in the chamber is replaced with gas supplied from outside the chamber.
[6] The step 2 includes grinding the workpiece,
The above [1] to [5], wherein the energy beam irradiation step is performed at least at any time after the step of attaching the workpiece in step 1 and before the step of grinding the workpiece. A method for manufacturing a semiconductor device according to any one of the above.
[7] The step 1 is a step of performing the support attaching step after the processing object attaching step,
The method for manufacturing a semiconductor device according to any one of [1] to [6] above, wherein the energy beam irradiation step is performed after the object attachment step and before the support attachment step.
[8] All layers other than the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet and the support have energy ray transparency,
The above [1], wherein the energy ray irradiation step is performed by irradiating the energy ray from the side of the support after the step of attaching the support in the step 1 and before the step 3 at least at any time. A method for manufacturing a semiconductor device according to any one of [7].
[9] The method for manufacturing a semiconductor device according to any one of [1] to [8] above, wherein the thermally expandable particles have an expansion start temperature (t) of 50°C or higher and lower than 125°C.
[10] The double-sided pressure-sensitive adhesive sheet further has a base layer (Y), and the pressure-sensitive adhesive layer (X1), the base layer (Y), and the pressure-sensitive adhesive layer (X2) are The method for manufacturing a semiconductor device according to any one of the above [1] to [9], comprising:
[11] The method of manufacturing a semiconductor device according to [10] above, wherein at least one of the adhesive layer (X1) and the base layer (Y) is the thermally expandable layer.
[12] The step 2 includes a step of grinding and singulating the workpiece,
As a preliminary step for singulation of the object to be processed,
A step of forming a groove as a dividing line on the surface of the object to be processed that is attached to the adhesive layer (X2) before the step of grinding and singulating, or the grinding and singulation a step of forming a modified region, which is a line to be divided, inside the object before the step of converting,
The step of grinding and singulating the object to be processed is performed on the adhesive layer (X2) of the object to be processed in a state in which the object to be processed is supported by the support via the double-sided adhesive sheet. The above [ 1] A method for manufacturing a semiconductor device according to any one of [11].

According to the present invention, an object to be processed is attached to the pressure-sensitive adhesive layer that is the outer layer on one side of the double-sided pressure-sensitive adhesive sheet, and a support is attached to the adhesive layer that is the outer layer on the other side of the double-sided pressure-sensitive adhesive sheet. It is possible to provide a method for manufacturing a semiconductor device to be processed, in which the object to be processed and the support can be easily separated from the double-sided pressure-sensitive adhesive sheet after processing.

1 is a cross-sectional view showing an example of the configuration of a double-sided pressure-sensitive adhesive sheet used in the production method of the present invention; FIG. FIG. 4 is a cross-sectional view showing another example of the configuration of the double-sided pressure-sensitive adhesive sheet used in the production method of the present invention; It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention. It is a sectional view explaining an example of a process of a manufacturing method of a semiconductor device of the present invention.

In this specification, the lower and upper limits described stepwise for preferable numerical ranges (for example, ranges of contents, etc.) can be independently combined. For example, from the statement "preferably 10 to 90, more preferably 30 to 60", combining "preferred lower limit (10)" and "more preferred upper limit (60)" to "10 to 60" can also

For the sake of convenience, the drawings used in the description of this specification show the main parts enlarged or simplified. Therefore, the dimensional ratio, number, etc. of each component are not necessarily the same as in reality.

The mechanism of action described in this specification is speculation, and does not limit the mechanism of the effects of the present invention.

As used herein, the term "active ingredient" means an ingredient excluding the diluent solvent among the ingredients contained in the target composition.

As used herein, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.

In this specification, the term "semiconductor device" means all devices that can function by utilizing semiconductor characteristics. Examples of semiconductor devices include 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. and electronic equipment.

As used herein, the term "energy ray" means an electromagnetic wave or charged particle beam having an energy quantum, and examples thereof include electromagnetic radiation such as ultraviolet rays and gamma rays; particle radiation such as electron beams.
As used herein, "energy ray-polymerizable" means the property of polymerizing by irradiation with energy rays. Moreover, "energy ray curability" means the property of being cured by irradiation with an energy ray.

In this specification, whether a "layer" is a "non-thermally expandable layer" or a "thermally expandable layer" is determined by the following method.
When the layer to be judged contains thermally expandable particles, the layer is heat-treated for 3 minutes at the expansion start temperature (t) of the thermally expandable particles. If the volume change rate calculated from the following formula is less than 5%, the layer is determined to be a "non-thermally expandable layer", and if it is 5% or more, the layer is a "thermally expandable layer". judge 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} x 100
In this specification, when the "layer" is a non-thermally expandable layer, the volume change rate (%) of the non-thermally expandable layer calculated from the above formula is less than 5%, preferably less than 2%, More preferably less than 1%, still more preferably less than 0.1%, even more preferably less than 0.01%.
Further, in this specification, when the non-thermally expandable layer does not substantially contain thermally expandable particles, and the layer to be evaluated does not substantially contain thermally expandable particles, the layer is referred to as "non-thermally It is judged to be an inflatable layer. Specifically, the content of the thermally expandable particles in the non-thermally expandable layer is preferably less than 3% by mass, more preferably 1% by mass, relative to the total mass (100% by mass) of the non-thermally expandable layer. %, more preferably less than 0.1% by weight, even more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight, and is most preferably free of thermally expandable particles.

In this specification, the "circuit surface" of the semiconductor wafer means the surface on which the circuits are formed, and the "back surface" of the semiconductor wafer means the surface on which the circuits are not formed.

In this specification, the thickness of each layer is the thickness at 23°C, specifically the value measured based on the method described in the Examples.

In this specification, the adhesive strength of each layer means the adhesive strength to the mirror surface of the silicon mirror wafer, and in an environment of 23° C. and 50% RH (relative humidity), 180° peeling based on JIS Z0237:2000. means the adhesive force measured at a pulling speed of 300 mm/min according to the Law.

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, specifically a value measured based on the method described in Examples. is.

In this specification, the total light transmittance is a value obtained by measuring a transmission spectrum by ultraviolet-visible spectroscopy, specifically a value measured based on the method described in Examples.

[Method for manufacturing a semiconductor device]
The method for manufacturing a semiconductor device according to the first aspect of the present invention (hereinafter also referred to as the “method for manufacturing the first aspect”) comprises:
At least having an adhesive layer (X1) as an outer layer on one side and an adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
Using a double-sided pressure-sensitive adhesive sheet in which at least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step The method for manufacturing a semiconductor device includes the following energy beam irradiation step after the process object attaching step of the step 1 and before the step 3 at least at any time.
Energy ray irradiation step: A step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2) without expanding the thermally expandable particles.

The method for manufacturing a semiconductor device according to the second aspect of the present invention (hereinafter also referred to as the "manufacturing method of the second aspect") uses the double-sided pressure-sensitive adhesive sheet and includes the steps 1 to 4 in this order,
A method for manufacturing a semiconductor device, comprising the following energy beam irradiation step at least at any time after step 1 of attaching an object to be processed and before step 3.
Energy beam irradiation step: the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet so that the temperature of the thermally expandable layer does not exceed a temperature lower than the expansion start temperature (t) of the thermally expandable particles by 5°C. The step of curing the pressure-sensitive adhesive layer (X2) by irradiating with an energy ray

The method for manufacturing a semiconductor device according to the third aspect of the present invention (hereinafter also referred to as the "manufacturing method of the third aspect") comprises:
A double-sided pressure-sensitive adhesive sheet having at least a pressure-sensitive adhesive layer (X1) as an outer layer on one side and a pressure-sensitive adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
At least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
A laminate obtained by laminating a glass plate made of soda lime glass and having a thickness of 1.1 mm on the adhesive layer (X2) of the double-sided adhesive sheet was placed at a temperature of 22°C + the expansion start temperature (t) of the thermally expandable particles. Using a double-sided adhesive sheet having a total light transmittance (T _A ) at a wavelength of 380 nm in the thickness direction of the laminate (L _A ) for measuring the total light transmittance obtained by heating for 1 minute at a temperature of less than 20%,
Having the above steps 1 to 4 in this order,
The method for manufacturing a semiconductor device includes the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy ray irradiation step: a step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2)

In addition, unless otherwise specified, the following description shall explain all of the manufacturing methods of the first, second and third aspects.

In the production method of the present embodiment, the outer layer on one side has an adhesive layer (X1) that is a heat-peelable adhesive layer, and the outer layer on the other side is an energy ray-curable adhesive layer. Using a double-sided pressure-sensitive adhesive sheet having a certain pressure-sensitive adhesive layer (X2), a support is attached to the pressure-sensitive adhesive layer (X1), and the processing object is processed in a state in which the processing target is attached to the pressure-sensitive adhesive layer (X2). . In this way, the pressure-sensitive adhesive layer on one side of the double-sided pressure-sensitive adhesive sheet and the pressure-sensitive adhesive layer on the other side of the double-sided pressure-sensitive adhesive sheet have different mechanisms of action for reducing the adhesive force, so that the pressure-sensitive adhesive layer on either side is It is possible to avoid unintentionally lowering the adhesive strength of the other adhesive layer when performing the treatment for reducing the adhesive strength.
After processing the object to be processed, the double-sided pressure-sensitive adhesive sheet is peeled off from the support and the object after processing. An energy ray irradiation step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2) is also included. That is, according to the production method of the present embodiment, the expansion of the thermally expandable particles in the thermally expandable layer is still suppressed when the pressure-sensitive adhesive layer (X2) is irradiated with energy rays. When the pressure-sensitive adhesive layer (X2) is irradiated with energy rays after the thermally expandable particles in the thermally expandable layer have expanded, the transmittance of the energy rays in the thermally expandable layer decreases due to the expanded thermally expandable particles. This makes it difficult for the irradiated energy rays to reach the pressure-sensitive adhesive layer (X2). Therefore, curing of the pressure-sensitive adhesive layer (X2) may be insufficient. On the other hand, according to the production method of the present embodiment, the energy beam irradiated toward the pressure-sensitive adhesive layer (X2) can reach the pressure-sensitive adhesive layer (X2) satisfactorily even through the thermally expandable layer. is. As a result, the pressure-sensitive adhesive layer (X2) can be efficiently cured, and the processed object can be easily separated from the pressure-sensitive adhesive layer (X2).

The double-sided pressure-sensitive adhesive sheets used in the manufacturing methods of the first, second, and third embodiments will be described first, and then each step will be described.

[Double-sided adhesive sheet]
The double-sided pressure-sensitive adhesive sheet used in the production method of the present embodiment (hereinafter also referred to as "double-sided pressure-sensitive adhesive sheet of the present embodiment") includes a pressure-sensitive adhesive layer (X1) as an outer layer on one side and a and a pressure-sensitive adhesive layer (X2) as an outer layer, the pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer, and at least one of the layers other than the pressure-sensitive adhesive layer (X2) is heated. A thermally expandable layer containing expandable particles.

From the viewpoint of simplifying the configuration, the double-sided pressure-sensitive adhesive sheet of this embodiment may have only the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2). From the viewpoint of improving the handleability of the double-sided pressure-sensitive adhesive sheet and the processing accuracy of the object to be processed, it further has a base layer (Y), the pressure-sensitive adhesive layer (X1), the base layer (Y), and the adhesive and agent layer (X2) in this order.

1(a) and 1(b) show schematic cross-sectional views of the double-sided pressure-sensitive adhesive sheet of this embodiment.
The double-sided pressure-sensitive adhesive sheet 1a shown in FIG. 1(a) is a double-sided pressure-sensitive adhesive sheet having only the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2).
The double-sided pressure-sensitive adhesive sheet 1b shown in FIG. 1(b) is a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer (X1), a base layer (Y), and a pressure-sensitive adhesive layer (X2) in this order.

<Thermal expansion layer>
In the double-sided PSA sheet of this embodiment, at least one of the layers other than the PSA layer (X2) is a thermally expandable layer containing thermally expandable particles.
The number of thermally expandable layers may be one, or two or more, but preferably one.
The thermally expandable layer may be the adhesive layer (X1) or a layer other than the adhesive layer (X1). When the double-sided pressure-sensitive adhesive sheet of the present embodiment has a base layer (Y), at least one of the pressure-sensitive adhesive layer (X1) and the base layer (Y) is preferably a thermally expandable layer, More preferably, the substrate layer (Y) is a thermally expandable layer.
When the substrate layer (Y) is a thermally expandable layer, unevenness due to the thermally expandable particles before thermal expansion is less likely to appear on the surface of the adhesive layer (X1), and the adhesive layer (X1) and the support It tends to have good adhesion to the body.

The thickness of the thermally expandable layer needs to be appropriately determined depending on which layer is the thermally expandable layer among the layers of the double-sided pressure-sensitive adhesive sheet of the present embodiment. from the viewpoint of improving the adhesiveness, the winding aptitude when the double-sided pressure-sensitive adhesive sheet is produced in a long state, etc. is more preferred.

(Thermal expandable particles)
The thermally expandable particles are not particularly limited as long as they are particles that expand when heated.
The thermally expandable particles may be used singly or in combination of two or more.

The expansion initiation temperature (t) of the thermally expandable particles is preferably 50° C. or higher and lower than 225° C., more preferably 55 to 200° C., still more preferably 60 to 180° C., even more preferably 70 to 155° C., still more preferably is 75-130°C.
When the expansion start temperature (t) of the thermally expandable particles is 50° C. or higher, it tends to be possible to suppress unintended expansion due to frictional heat generated when processing an object to be processed, reaction heat during the energy beam irradiation step, and the like. be. Further, when the expansion start temperature (t) of the thermally expandable particles is less than 225°C, there is a tendency that the thermal change of the object to be processed during thermal separation can be suppressed.
In addition to the above reasons, when a thermosetting film is attached to the back surface of the object to be processed in step 3 described later, from the viewpoint of suppressing the progress of an unintended curing reaction of the thermosetting film, etc. It is preferable to lower the expansion start temperature (t) of the thermally expandable particles. Specifically, it may be in the range of 50.degree.

In this specification, the expansion start temperature (t) of thermally expandable particles means a value measured based on the following method.
<<Method for measuring expansion start temperature (t) of thermally expandable particles>>
An aluminum cup with a diameter of 6.0 mm (inner diameter of 5.65 mm) and a depth of 4.8 mm was filled with 0.5 mg of thermally expandable particles to be measured, and an aluminum lid (5.6 mm in diameter and 0.6 mm in thickness) was placed on top of the cup. 1 mm) is placed on the sample.
Using a dynamic viscoelasticity measuring device, the height of the sample is measured while a force of 0.01 N is applied to the sample from the top of the aluminum lid with a pressurizer. Then, with a force of 0.01 N applied by the pressurizer, it was heated from 20° C. to 300° C. at a temperature increase rate of 10° C./min, and the amount of displacement in the vertical direction of the pressurizer was measured. Let the displacement start temperature be the expansion start temperature (t).

The thermally expandable particles are preferably microencapsulated foaming agents composed of an outer shell made of a thermoplastic resin and an encapsulated component that is encapsulated in the outer shell and vaporizes when heated to a predetermined temperature. .
The thermoplastic resin constituting the outer shell of the microencapsulated foaming agent includes, for example, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, or structural units contained in these thermoplastic resins. Examples thereof include copolymers obtained by polymerizing two or more of the monomers to be formed.

Examples of encapsulated components that are encapsulated in the outer shell of the microencapsulated foaming agent include propane, propylene, butene, n-butane, isobutane, isopentane, neopentane, n-pentane, n-hexane, isohexane, n- Low boiling point liquids such as heptane, n-octane, cyclopropane, cyclobutane, and petroleum ether are included. Among these, when the expansion start temperature (t) of the thermally expandable particles is 50° C. or higher and lower than 125° C., propane, isobutane, n-pentane, and cyclopropane are preferable as the encapsulated component.
One type of inclusion component may be used alone, or two or more types may be used in combination.
The expansion start temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of inclusion component.

The average particle diameter (D ₅₀ ) of the thermally expandable particles before expansion at 23° C. is preferably 3 to 100 μm, more preferably 4 to 70 μm, even more preferably 6 to 60 μm, still more preferably 10 to 50 μm.
The 90% particle diameter (D ₉₀ ) of the thermally expandable particles before expansion at 23° C. is preferably 10 to 150 μm, more preferably 15 to 100 μm, still more preferably 20 to 90 μm, still more preferably 25 to 80 μm. .
The average particle size (D ₅₀ ) and 90% particle size (D ₉₀ ) of the thermally expandable particles before expansion can be measured by the method described in Examples.

The maximum volume expansion coefficient when heated to a temperature equal to or higher than the expansion start temperature (t) of the thermally expandable particles is preferably 1.5 to 200 times, more preferably 2 to 150 times, and still more preferably 2.5 to 120. times, more preferably 3 to 100 times.

The content of the thermally expandable particles in the thermally expandable layer is preferably 3 to 45% by mass, more preferably 7 to 40% by mass, and still more preferably the total mass (100% by mass) of the thermally expandable layer. is 10 to 35% by mass.
When the content of the thermally expandable particles is 3% by mass or more, the peelability tends to be improved during heat peeling. Further, when the content of the thermally expandable particles is 45% by mass or less, the thermally expandable particles and other components tend to be easily mixed in the preparation of the composition for forming the thermally expandable layer. be.

<Adhesive layer (X1)>
The pressure-sensitive adhesive layer (X1) is a pressure-sensitive adhesive layer as an outer layer on one side of the double-sided pressure-sensitive adhesive sheet of the present embodiment.
The pressure-sensitive adhesive layer (X1) is a layer on the surface of which irregularities are formed due to thermally expandable particles expanded by heating. The contact area is reduced and it can be easily peeled off from the adherend.
The adhesive layer (X1) can be formed, for example, from an adhesive composition (x-1) containing an adhesive resin.

(Adhesive composition (x-1))
The adhesive composition (x-1) contains an adhesive resin.

[Adhesive resin]
As the adhesive resin, for example, a polymer having adhesiveness by itself and having a mass average molecular weight (Mw) of 10,000 or more can be mentioned. In addition, adhesive resin may not have adhesiveness by itself, but may express adhesiveness by addition of a tackifier or a plasticizer.
The mass average molecular weight (Mw) of the adhesive resin is preferably 10,000 to 2,000,000, more preferably 20,000 to 1,500,000, and still more preferably 30,000 to 100, from the viewpoint of improving the adhesive strength of the adhesive layer (X1). Ten thousand.
Adhesive resin may be used individually by 1 type, and may use 2 or more types together.

The tacky resin may be a polymer having a single structural unit, or a copolymer having two or more structural units. When the adhesive resin is a copolymer, the form of the copolymer may be block copolymer, random copolymer or graft copolymer.

Examples of adhesive resins include acrylic resins, urethane resins, polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins. Among these, the adhesive resin preferably contains an acrylic resin from the viewpoint of expressing excellent adhesive strength in the adhesive layer (X1).

The content of the acrylic resin in the adhesive resin is preferably 30 to 100% by mass, more preferably 30 to 100% by mass, based on the total amount (100% by mass) of the adhesive resin contained in the adhesive composition (x-1). is 50 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 85 to 100% by mass.

The mass average molecular weight (Mw) of the acrylic resin is preferably 100,000 to 1,500,000, more preferably 200,000 to 1,300,000, still more preferably 350,000 to 1,200,000, and even more preferably 500,000 to 1,100,000.

Examples of acrylic resins include polymers containing structural units derived from alkyl (meth)acrylates having alkyl groups, polymers containing structural units derived from (meth)acrylates having a cyclic structure, and the like. . Among these, a polymer containing a structural unit derived from an alkyl (meth)acrylate having an alkyl group is preferable, and is derived from an alkyl (meth)acrylate (a1′) (hereinafter also referred to as “monomer (a1′)”). and a functional group-containing monomer (a2′) (hereinafter also referred to as “monomer (a2′)”).

The number of carbon atoms in the alkyl group of the monomer (a1′) is preferably 1 to 24, more preferably 1 to 12, and even more preferably 2 to 2, from the viewpoint of exhibiting excellent adhesive strength in the adhesive layer (X1). 10, more preferably 4-8.
In this specification, unless otherwise specified, the "alkyl group" may be linear or branched.

Examples of the monomer (a1′) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, iso-butyl (meth)acrylate, Acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate and the like. Among these, n-butyl acrylate and 2-ethylhexyl acrylate are preferred.
Monomer (a1′) may be used alone or in combination of two or more.

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 units (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 functional groups possessed by the monomer (a2′) include hydroxyl groups, carboxyl groups, amino groups, epoxy groups and the like.
That is, examples of the monomer (a2′) include hydroxyl group-containing monomers, carboxy group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like. Among these, hydroxyl group-containing monomers and carboxy group-containing monomers are preferable, and hydroxyl group-containing monomers are more preferable.
Monomer (a2') may be used alone or in combination of two or more.

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

Carboxy group-containing monomers include, for example, 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 units (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 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, still more preferably 95 to 100% by mass.

The content of the adhesive resin in the adhesive composition (x-1) is preferably 35 to 100% by mass with respect to the total amount (100% by mass) of the active ingredients in the adhesive composition (x-1), More preferably 50 to 100% by mass, still more preferably 60 to 100% by mass, still more preferably 70 to 99.5% by mass.

[Crosslinking agent]
When the pressure-sensitive adhesive composition (x-1) contains a pressure-sensitive adhesive resin having a functional group, it preferably further contains a cross-linking agent.
The cross-linking agent reacts with the adhesive resin having a functional group to cross-link the adhesive resins with each other using the functional group as a cross-linking starting point.

Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and metal chelate-based cross-linking agents.
The cross-linking agents may be used alone or in combination of two or more.
Among these cross-linking agents, isocyanate-based cross-linking agents are preferable from the viewpoints of increasing cohesive strength and improving adhesive strength, and from the viewpoints of availability and the like.
Examples of isocyanate-based cross-linking agents include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; Alicyclic polyisocyanates such as methylcyclohexylene diisocyanate, methylenebis(cyclohexyl isocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, hydrogenated xylylene diisocyanate; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate acyclic aliphatic polyisocyanates such as; polyvalent isocyanate compounds such as;
Examples of the isocyanate-based cross-linking agent include trimethylolpropane adduct-type modified products of the above polyvalent isocyanate compounds, biuret-type modified products reacted with water, and isocyanurate-type modified products containing an isocyanurate ring.
Among these, it contains an isocyanurate ring from the viewpoint of suppressing a decrease in the elastic modulus of the pressure-sensitive adhesive layer (X1) during heating and suppressing adhesion of residues derived from the pressure-sensitive adhesive layer (X1) to the support. It is preferable to use an isocyanurate-type modified product, more preferably to use an isocyanurate-type modified product of acyclic aliphatic polyisocyanate, and even more preferably to 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 possessed by the adhesive resin. More preferably 0.03 to 7 parts by mass, still more preferably 0.05 to 5 parts by mass.

[Tackifier]
The pressure-sensitive adhesive composition (x-1) may further contain a tackifier from the viewpoint of further improving the adhesive strength.
As used herein, the term "tackifier" refers to a component that supplementarily improves the adhesive strength of the adhesive resin and has a weight-average molecular weight (Mw) of less than 10,000.
The weight average molecular weight (Mw) of the tackifier is less than 10,000, preferably 400 to 9,000, more preferably 500 to 8,000, still more preferably 800 to 5,000.

Examples of tackifiers include rosin-based resins, terpene-based resins, styrene-based resins, pentene produced by thermal decomposition of petroleum naphtha, isoprene, piperine, obtained by copolymerizing C5 fractions such as 1,3-pentadiene. C5 petroleum resins obtained by thermal decomposition of petroleum naphtha, C9 petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene generated by thermal decomposition of petroleum naphtha, and hydrogenated resins obtained by hydrogenating these.

The content of the tackifier is preferably 0.01 to 65% by mass, more preferably 0.1 to 50% by mass, relative to the total amount (100% by mass) of the active ingredients of the adhesive composition (x-1). %, more preferably 1 to 40% by mass, and even more preferably 2 to 30% by mass.

[Additive for adhesive]
The pressure-sensitive adhesive composition (x-1) may contain additives for pressure-sensitive adhesives used in general pressure-sensitive adhesives, in addition to the components described above, as long as the effects of the present invention are not impaired.
Examples of adhesive additives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), and ultraviolet absorbers.
In addition, the additives for pressure-sensitive adhesives may be used alone, respectively, or two or more of them may be used in combination.

When the pressure-sensitive adhesive composition (x-1) contains a pressure-sensitive adhesive additive, the content of each pressure-sensitive adhesive additive is independently preferably 0 per 100 parts by mass of the pressure-sensitive adhesive resin. 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass.

(Polymerizable composition)
When the pressure-sensitive adhesive layer (X1) is a thermally expandable layer, the pressure-sensitive adhesive layer (X1) may be formed from the above-described pressure-sensitive adhesive composition (x-1), but the heat from the drying step after application From the viewpoint of suppressing the expansion of the expandable particles, it is preferable to irradiate the polymerizable composition containing the energy ray-polymerizable component and the thermally expandable particles with an energy ray. By using a polymerizable composition for forming the pressure-sensitive adhesive layer (X1), there is no need to use a solvent and the drying step can be omitted, so the thermally expandable particles having a relatively low expansion initiation temperature (t) can be selected.
As the energy ray-polymerizable component, for example, various monomers exemplified as raw material monomers for the acrylic resin described above as the adhesive resin can be used.
The polymerizable composition preferably contains a photopolymerization initiator from the viewpoint of sufficiently advancing the energy ray polymerization reaction. As the photopolymerization initiator, the photopolymerization initiator described in the solventless resin composition (y-1a) described later can be used. In addition, the polymerizable composition may contain the crosslinking agent, tackifier, adhesive additive, etc. described in the above adhesive composition (x-1).

(Adhesive strength of the adhesive layer (X1) before thermally expanding the thermally expandable layer)
The adhesive strength of the pressure-sensitive adhesive layer (X1) before thermally expanding the thermally expandable layer is preferably 0.1 to 12.0 N/25 mm, more preferably 0.5 to 9.0 N/25 mm, still more preferably 1 .0 to 8.0 N/25 mm, more preferably 1.2 to 7.5 N/25 mm.
When the adhesive strength of the adhesive layer (X1) before thermally expanding the thermally expandable layer is 0.1 N/25 mm or more, unintended peeling from the support during temporary fixing, positional displacement, etc. can be more effectively prevented. tend to be suppressed. Further, when the adhesive strength is 12.0 N/25 mm or less, the peelability at the time of heat peeling can be further improved.

(Adhesive strength of adhesive layer (X1) after thermally expanding the thermally expandable layer)
The adhesive strength of the adhesive layer (X1) after thermal expansion of the thermally expandable layer is preferably 1.5 N/25 mm or less, more preferably 0.05 N/25 mm or less, and still more preferably 0.01 N/25 mm or less. , and more preferably 0 N/25 mm. The adhesive force of 0 N/25 mm means an adhesive force below the measurable limit in the method for measuring adhesive force described above. A case of unintentional peeling is also included.

(Thickness of adhesive layer (X1))
The thickness of the adhesive layer (X1) expresses good adhesive strength, and when a layer other than the adhesive layer (X1) such as the base layer (Y) is a thermally expandable layer, the thermal expansion From the viewpoint of forming good unevenness on the adhesive surface of the adhesive layer (X1) when the thermally expandable particles in the adhesive layer are expanded by heating, it is preferably 3 to 10 μm, more preferably 3 to 8 μm, and further It is preferably 3 to 7 μm.

<Base material layer (Y)>
The substrate layer (Y) is preferably a layer made of a non-adhesive substrate.
The probe tack value on the surface of the substrate layer (Y) is usually less than 50 mN/5 mmφ, preferably less than 30 mN/5 mmφ, more preferably less than 10 mN/5 mmφ, still more preferably less than 5 mN/5 mmφ.
In addition, in this specification, the probe tack value on the surface of the substrate means the value measured by the following method.
≪How to measure the probe tack value≫
After cutting the base material to be measured into a square with a side of 10 mm, a test sample was left to stand in an environment of 23 ° C. and 50% RH (relative humidity) for 24 hours. ), using a tacking tester (manufactured by Nippon Tokushu Sokki Co., Ltd., product name “NTS-4800”), the probe tack value on the surface of the test sample is measured in accordance with JIS Z0237: 1991. be able to. Specifically, a stainless steel probe with a diameter of 5 mm was brought into contact with the surface of the test sample at a contact load of 0.98 N/cm ² for 1 second, and then the probe was moved at a speed of 10 mm/second to the surface of the test sample. The force required to remove it from the surface can be measured and the resulting value taken as the probe tack value for that test sample.

The substrate layer (Y) may be subjected to, for example, a surface treatment such as an oxidation method or a roughening method, an adhesion-facilitating treatment, or a primer treatment, from the viewpoint of improving interlayer adhesion with other layers.
Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone, ultraviolet irradiation treatment, etc. Examples of roughening methods include sandblasting, solvent treatment, and the like. is mentioned.

The substrate layer (Y) may be a thermally expandable layer (hereinafter also referred to as “thermally expandable substrate layer (Y1)”), a non-thermally expandable layer (hereinafter, “non-thermally expandable substrate layer (Y2)”).
When the substrate layer (Y) includes the thermally expandable substrate layer (Y1), the deformation of the thermally expandable substrate layer (Y1) due to the expansion of the thermally expandable particles is well transmitted to the adhesive layer (X1). From a viewpoint, it is preferable to include a non-thermally expandable substrate layer (Y2) together with the thermally expandable substrate layer (Y1). That is, the double-sided pressure-sensitive adhesive sheet of the present embodiment comprises a pressure-sensitive adhesive layer (X1), a thermally expandable base layer (Y1), a non-thermally expandable base layer (Y2), and a pressure-sensitive adhesive layer (X2). , in this order.
In FIG. 2, an adhesive layer (X1), a thermally expandable substrate layer (Y1), a non-thermally expandable substrate layer (Y2), and an adhesive layer (X2) are laminated in this order. A cross-sectional schematic diagram of a double-sided pressure-sensitive adhesive sheet 1c having a laminated structure is shown.

<Thermal expandable base layer (Y1)>
The thermally expandable substrate layer (Y1) can be formed, for example, from a resin composition (y-1) containing a resin and thermally expandable particles.

(Resin composition (y-1))
Resin composition (y-1) is a resin composition containing a resin and thermally expandable particles.

〔resin〕
The resin may be a non-adhesive resin or a tacky resin. Even if the resin contained in the resin composition (y-1) is an adhesive resin, in the process of forming the thermally expandable base layer (Y1) from the resin composition (y-1), the adhesive resin is It suffices that the polymerizable compound undergoes a polymerization reaction, the resulting resin becomes a non-adhesive resin, and the thermally expandable substrate layer (Y1) becomes non-adhesive.
One of the resins may be used alone, or two or more of them may be used in combination.

The mass average molecular weight (Mw) of the resin is preferably 1,000 to 1,000,000, more preferably 1,000 to 700,000, and still more preferably 1,000 to 500,000.

The resin may be a polymer having a single structural unit, or a copolymer having two or more structural units. When the resin is a copolymer, the form of the copolymer may be block copolymer, random copolymer or graft copolymer.

As the resin contained in the resin composition (y-1), from the viewpoint of facilitating the formation of unevenness on the adhesive surface of the pressure-sensitive adhesive layer (X1) and from the viewpoint of improving the sheet shape retention after thermal expansion, It preferably contains one or more selected from the group consisting of acrylic urethane resins and olefin resins.

≪Acrylic urethane resin≫
As the acrylic urethane resin, the following acrylic urethane resin (U1) is preferable.
• An acrylic urethane resin (U1) obtained by polymerizing a urethane prepolymer (UP) and a vinyl compound containing a (meth)acrylic acid ester.
In the present specification, the term "prepolymer" means a compound obtained by polymerizing a monomer and capable of forming a polymer by further polymerization.

Urethane prepolymers (UP) include reaction products of polyols and polyvalent isocyanates.
In addition, it is preferable that the urethane prepolymer (UP) is obtained by subjecting the urethane prepolymer (UP) to a chain extension reaction using a chain extension agent.

Examples of polyols used as raw materials for urethane prepolymers (UP) include alkylene-type polyols, ether-type polyols, ester-type polyols, esteramide-type polyols, ester/ether-type polyols, and carbonate-type polyols.
These polyols may be used alone or in combination of two or more.
The polyol is preferably a diol, more preferably an ester-type diol, an alkylene-type diol or a carbonate-type diol, and still more preferably an ester-type diol or a carbonate-type diol.

Examples of ester diols include alkanediols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol and 1,6-hexanediol; ethylene glycol, propylene glycol, 1 or 2 or more selected from diols such as alkylene glycols such as diethylene glycol and dipropylene glycol; ,4'-dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, het acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, hexa Condensation products of one or more selected from dicarboxylic acids such as hydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid, and anhydrides thereof may be mentioned.
Specifically, for example, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene hexamethylene adipate diol, polydiethylene adipate diol, poly(polytetramethylene ether) adipate diol, poly(3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol, polyneopentyl terephthalate diol and the like.

Examples of polyvalent isocyanates used as raw materials for urethane prepolymers (UP) include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates.
Polyvalent isocyanate may be used individually by 1 type, and may use 2 or more types together.
Further, the polyvalent isocyanate 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, diisocyanates are preferred as polyvalent isocyanates, and 4,4′-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2, 6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanates are more preferred.

Alicyclic diisocyanates include, for example, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane Examples include diisocyanate, methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexanediisocyanate, and isophorone diisocyanate (IPDI) is preferred.

The urethane prepolymer (UP) is preferably a linear urethane prepolymer having ethylenically unsaturated groups at both ends.
Examples of ethylenically unsaturated groups include (meth)acryloyl groups, vinyl groups, and allyl groups, and among these, (meth)acryloyl groups are preferred.
As a method for introducing ethylenically unsaturated groups at both ends of a straight-chain urethane prepolymer, for example, an NCO group at the end of the straight-chain urethane prepolymer obtained by reacting a diol with a diisocyanate compound and a hydroxyalkyl (meth) A method of reacting with acrylate can be mentioned.
Examples of the hydroxyalkyl (meth)acrylate to be reacted with the terminal NCO group include the same hydroxyalkyl (meth)acrylates as the monomer (a2′) described above.

≪Olefin resin≫
An olefin resin is a polymer having at least structural units derived from an olefin monomer.
As the olefin monomer, α-olefins having 2 to 8 carbon atoms are preferable, and specific examples include ethylene, propylene, butylene, isobutylene, 1-hexene, and the like. Among these, ethylene and propylene are preferred.

The olefin-based resin may be a modified olefin-based resin that has undergone one or more modifications selected from acid modification, hydroxyl modification, and acrylic modification.

Examples of the acid-modified olefin resin obtained by subjecting an olefin resin to acid modification include a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or its anhydride to an unmodified olefin resin. be done.
Examples of unsaturated carboxylic acids or anhydrides thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth)acrylic acid, maleic anhydride, itaconic anhydride, and anhydride. glutaconic acid, citraconic anhydride, aconitic anhydride, norbornenedicarboxylic anhydride, tetrahydrophthalic anhydride and the like.
One type of unsaturated carboxylic acid or its anhydride may be used alone, or two or more types may be used in combination.

Examples of acrylic-modified olefin-based resins obtained by subjecting olefin-based resins to acrylic modification include, for example, modification obtained by graft-polymerizing alkyl (meth)acrylates as side chains to unmodified olefin-based resins that are main chains. polymers.
The number of carbon atoms in the alkyl group of the alkyl (meth)acrylate is preferably 1-20, more preferably 1-16, still more preferably 1-12.
Examples of alkyl (meth)acrylates include the same alkyl (meth)acrylates listed above as the monomer (a1′).

Examples of the hydroxyl group-modified olefin resin obtained by modifying the olefin resin with hydroxyl groups include a modified polymer obtained by graft-polymerizing a hydroxyl group-containing compound to an unmodified olefin resin that is the main chain.
The hydroxyl group-containing compound includes, for example, the same hydroxyl group-containing compounds as the monomer (a2′) described above.

<<Resins other than acrylic urethane resins and olefin resins>>
The resin composition (y-1) may contain a resin other than the acrylic urethane-based resin and the olefin-based resin within a range that does not impair the effects of the present invention.
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 copolymer; Coalescence; cellulose triacetate; polycarbonate; polyurethane not applicable to acrylic urethane resins; polysulfone; polyetheretherketone; polyethersulfone; polyphenylene sulfide; ; fluorine-based resins and the like.

However, from the viewpoint of improving the sheet shape retention property after thermal expansion, the content of the resin other than the acrylic urethane resin and the olefin resin in the resin composition (y-1) is preferably small, and is not contained. is more preferable.
When the resin composition (y-1) contains a resin other than the acrylic urethane resin and the olefin resin, the content thereof is the total amount (100% by mass) of the resin contained in the resin composition (y-1). , preferably less than 30% by mass, more preferably less than 20% by mass, even more preferably less than 10% by mass, even more preferably less than 5% by mass, and even more preferably less than 1% by mass.

[Base material additive]
The resin composition (y-1) may contain additives for base materials, if necessary, to the extent that the effects of the present invention are not impaired.
Examples of base material additives include ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, colorants, and the like.
The base material additives may be used alone or in combination of two or more.
When the resin composition (y-1) contains a base material additive, the content of each base material additive is preferably 0.0001 to 0.0001 to 100 parts by mass of the resin independently. 20 parts by mass, more preferably 0.001 to 10 parts by mass.

The resin composition (y-1) may be diluted with a solvent. Examples of the solvent include aromatic hydrocarbons such as toluene; esters such as ethyl acetate; ketones such as methyl ethyl ketone and acetone; and organic solvents such as alcohols such as isopropyl alcohol. However, as in the case where the pressure-sensitive adhesive layer (X1) contains thermally expandable particles, from the viewpoint of suppressing the expansion of the thermally expandable particles during the drying process after coating, the energy ray-polymerizable component and the thermally expandable It is preferable to form the thermally expandable substrate layer (Y1) by irradiating the solvent-free resin composition (y-1a) containing particles and containing no solvent with energy rays.

(Solvent-free resin composition (y-1a))
As one aspect of the solvent-free resin composition (y-1a), an oligomer having an ethylenically unsaturated group with a mass average molecular weight (Mw) of 50,000 or less as an energy ray-polymerizable component (hereinafter simply referred to as "ethylenic (also referred to as "an unsaturated group-containing oligomer"), an energy ray-polymerizable monomer, and the above-described thermally expandable particles, and a resin composition containing no solvent.
Although the solvent-free resin composition (y-1a) does not contain a solvent, the energy ray-polymerizable monomer contributes to improving the plasticity of the oligomer having an ethylenically unsaturated group.
By irradiating the solvent-free resin composition (y-1a) with an energy ray, an oligomer having an ethylenically unsaturated group, an energy ray-polymerizable monomer, etc. are polymerized to form a thermally expandable base layer (Y1 ) is formed.
Examples of the ethylenically unsaturated group include those mentioned above, and among these, a (meth)acryloyl group is preferred.

The weight average molecular weight (Mw) of the oligomer having an ethylenically unsaturated group is 50,000 or less, preferably 1,000 to 50,000, more preferably 2,000 to 40,000, still more preferably 3,000. 000 to 35,000, more preferably 4,000 to 30,000.

As the oligomer having an ethylenically unsaturated group, among the resins contained in the above resin composition (y-1), those having an ethylenically unsaturated group with a weight average molecular weight (Mw) of 50,000 or less. Among them, the urethane prepolymer (UP) described above is more preferable, and a linear urethane prepolymer having ethylenically unsaturated groups at both ends is even more preferable.
As the oligomer having an ethylenically unsaturated group, a modified olefinic resin having an ethylenically unsaturated group obtained by introducing an ethylenically unsaturated group into the above-described olefinic resin can also be used.

The total content of the oligomer having an ethylenically unsaturated group and the energy ray-polymerizable monomer in the solvent-free resin composition (y-1a) is the total amount (100 mass of the solvent-free resin composition (y-1a) %), preferably 70 to 99.5 mass%, more preferably 75 to 99.2 mass%, still more preferably 80 to 98.8 mass%, still more preferably 85 to 98.5 mass% be.

An energy ray-polymerizable monomer is a monomer having an energy ray-polymerizable functional group.
Examples of energy ray-polymerizable functional groups include ethylenically unsaturated groups such as (meth)acryloyl groups, vinyl groups, and allyl groups. Among these, a (meth)acryloyl group is preferred. The energy ray-polymerizable monomer may be an energy ray-polymerizable monofunctional monomer having only one energy ray-polymerizable functional group, or an energy ray-polymerizable polyfunctional monomer having two or more energy ray-polymerizable functional groups. However, from the viewpoint of obtaining a flexible thermally expandable substrate layer (Y1) that does not hinder the expansion of the thermally expandable particles, it is preferable to use at least an energy ray-polymerizable monofunctional monomer.
Energy ray-polymerizable monofunctional monomers include, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, alicyclic polymerizable compounds such as adamantane (meth)acrylate and tricyclodecane acrylate; aromatic polymerizable compounds such as phenylhydroxypropyl acrylate, benzyl acrylate, and phenol ethylene oxide-modified acrylate; Examples thereof include heterocyclic polymerizable compounds such as N-vinylpyrrolidone and N-vinylcaprolactam. Among these, isobornyl (meth)acrylate, phenylhydroxypropyl acrylate, and cyclohexyl (meth)acrylate are preferred.
The energy ray-polymerizable monomer may be used singly or in combination of two or more, or an energy ray-polymerizable monofunctional monomer and an energy ray-polymerizable polyfunctional monomer may be used in combination. good.

Content ratio of the oligomer having an ethylenically unsaturated group and the energy ray-polymerizable monomer in the solvent-free resin composition (y-1a) [oligomer having an ethylenically unsaturated group/energy ray-polymerizable monomer] is preferably 20/80 to 85/15, more preferably 25/75 to 80/20, still more preferably 30/70 to 75/25, in mass ratio.

The solvent-free resin composition (y-1a) preferably contains a photopolymerization initiator from the viewpoint of allowing the curing reaction to proceed sufficiently even when irradiated with relatively low-energy energy rays. .
Examples of photopolymerization initiators include 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzylphenyl sulfide, tetramethylthiuram. monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloroanthraquinone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and the like. Among these, 1-hydroxycyclohexylphenyl ketone is preferred.
A photoinitiator may be used individually by 1 type, and may use 2 or more types together.
The content of the photopolymerization initiator is preferably 0.01 to 5 parts by mass, more preferably 0.01, with respect to the total amount (100 parts by mass) of the oligomer having an ethylenically unsaturated group and the energy ray-polymerizable monomer. to 4 parts by mass, more preferably 0.02 to 3 parts by mass.

(Thickness of thermally expandable base layer (Y1))
The thickness of the thermally expandable substrate layer (Y1) before thermal expansion is preferably 15 to 250 μm, more preferably 50 to 225 μm, even more preferably 75 to 150 μm.
When the thickness of the thermally expandable base layer (Y1) before thermal expansion is 15 μm or more, unevenness caused by the thermally expandable particles before thermal expansion tends to be difficult to appear on the surface of the pressure-sensitive adhesive layer (X1). It is easy to improve the peelability at the time of heat peeling. Moreover, when the thickness of the thermally expandable substrate layer (Y1) before thermal expansion is 250 μm or less, the double-sided pressure-sensitive adhesive sheet tends to be excellent in handleability.

<Non-thermally expandable base layer (Y2)>
Examples of materials for forming the non-thermally expandable base material layer (Y2) include resins, metals, and paper materials.
Examples of resins include polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyester resins such as butylene terephthalate and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; polyethersulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyamide resins; acrylic resins;
Examples of metals include aluminum, tin, chromium, and titanium.
Examples of the paper material include thin paper, medium quality paper, fine paper, impregnated paper, coated paper, art paper, parchment paper, and glassine paper.
Among these, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate are preferred.

These forming materials may be composed of one type, or two or more types may be used in combination.
Examples of the non-thermally expandable base material layer (Y2) using a combination of two or more forming materials include those obtained by laminating a paper material with a thermoplastic resin such as polyethylene, a resin film containing a resin, or a sheet having a metal layer on its surface. Examples include those having a film formed thereon.
As a method for forming the metal layer, for example, the above metal is deposited by a PVD method such as vacuum deposition, sputtering, or ion plating, or a metal foil made of the above metal is attached using a general adhesive. and the like.

When the non-thermally expandable base material layer (Y2) contains a resin, it may contain the above base material additives that can also be contained in the resin composition (y-1) together with the resin.

(Storage elastic modulus E′ (23) at 23° C. of the non-thermally expandable base layer (Y2))
The storage 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 to 4.5×10 ⁹ Pa, more preferably 1.0×10 ⁹ to 4.0×10 ⁹ Pa.
When the storage elastic modulus E′(23) of the non-thermally expandable base material layer (Y2) is 5.0×10 ⁷ Pa or more, the deformation resistance of the double-sided PSA sheet tends to be easily improved. Moreover, when the storage elastic modulus E′(23) of the non-thermally expandable base layer (Y2) is 5.0×10 ⁹ Pa or less, the double-sided PSA sheet tends to be excellent in handleability.
In addition, in this specification, the storage elastic modulus E'(23) of the non-thermally expandable base layer (Y2) means a value measured by the method described in Examples.

(Thickness of non-thermally expandable base layer (Y2))
The thickness of the non-thermally expandable base layer (Y2) is preferably 5-500 μm, more preferably 15-300 μm, and still more preferably 20-200 μm.
When the thickness of the non-thermally expandable substrate layer (Y2) is 5 μm or more, the deformation resistance of the double-sided PSA sheet tends to be easily improved. Moreover, when the thickness of the non-thermally expandable base material layer (Y2) is 500 μm or less, the double-sided pressure-sensitive adhesive sheet tends to be excellent in handleability.

<Adhesive layer (X2)>
The pressure-sensitive adhesive layer (X2) is a pressure-sensitive adhesive layer as an outer layer on the other side of the double-sided pressure-sensitive adhesive sheet of the present embodiment, and is an energy ray-curable pressure-sensitive adhesive layer having the property of being cured by irradiation with energy rays. be.
The pressure-sensitive adhesive layer (X2) can be formed, for example, from a pressure-sensitive adhesive composition (x-2) containing an energy ray-polymerizable component.

(Adhesive composition (x-2))
The adhesive composition (x-2) contains an energy ray-polymerizable component.
As the energy ray-polymerizable component, it is preferable to contain an adhesive resin having an energy ray-polymerizable functional group (hereinafter also referred to as "energy ray-polymerizable adhesive resin"). In addition, the energy ray-polymerizable adhesive resin may not have adhesiveness by itself, and may express adhesiveness by adding a tackifier or a plasticizer.

[Energy beam polymerizable adhesive resin]
Examples of the energy ray-polymerizable functional group possessed by the energy ray-polymerizable adhesive resin include the same groups as those described above. Among these, a (meth)acryloyl group is preferred.
The energy ray-polymerizable adhesive resin may be used alone or in combination of two or more.

The energy ray-polymerizable adhesive resin may have a single structural unit, or may be a copolymer having two or more structural units. When the energy ray-polymerizable adhesive resin is a copolymer, the form of the copolymer may be any of block copolymer, random copolymer and graft copolymer.

Examples of energy ray-polymerizable adhesive resins include acrylic resins, urethane-based resins, rubber-based resins, and silicone-based resins that have energy ray-polymerizable properties. Among these, acrylic resins having energy ray polymerizability are preferred, and acrylic copolymers having energy ray polymerizability (hereinafter also referred to as “acrylic copolymer (A2)”) are more preferred.

The acrylic copolymer (A2) contains a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms from the viewpoint of further improving the adhesive strength of the pressure-sensitive adhesive layer (X2). is preferred.
Structural units derived from alkyl (meth)acrylates having an alkyl group with 4 or more carbon atoms may be used singly or in combination of two or more.
The number of carbon atoms in the alkyl group of the alkyl (meth)acrylate having 4 or more carbon atoms in the alkyl group is preferably 4 to 12, more preferably 4 to 8, and still more preferably 4 to 6.
Examples of alkyl (meth)acrylates in which the alkyl group has 4 or more carbon atoms include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, and nonyl (meth)acrylate. Acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate and the like. Among these, butyl (meth)acrylate is preferred, and butyl acrylate is more preferred.
From the viewpoint of adhesiveness, the content of the alkyl (meth)acrylate whose alkyl group has 4 or more carbon atoms is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, still more preferably 40 to 60% by mass.

From the viewpoint of improving the elastic modulus and adhesive properties of the pressure-sensitive adhesive layer (X2), the acrylic copolymer (A2) is a structural unit derived from an alkyl (meth)acrylate having an alkyl group having 4 or more carbon atoms. In addition, it preferably contains a structural unit derived from an alkyl (meth)acrylate having 1 to 3 carbon atoms in the alkyl group.
Structural units derived from alkyl (meth)acrylates in which the alkyl group has 1 to 3 carbon atoms may be used singly or in combination of two or more.
Examples of alkyl (meth)acrylates having 1 to 3 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate and the like. . Among these, methyl (meth)acrylate and ethyl (meth)acrylate are preferred, and methyl methacrylate and ethyl acrylate are more preferred.
The content of structural units derived from alkyl (meth)acrylates in which the alkyl group has 1 to 3 carbon atoms is preferably 1 in all structural units derived from acrylic monomers constituting the acrylic copolymer (A2). to 35% by mass, more preferably 5 to 30% by mass, and even more preferably 15 to 25% by mass.

The acrylic copolymer (A2) preferably further contains structural units derived from functional group-containing monomers.
By containing a structural unit derived from a functional group-containing monomer, the acrylic copolymer (A2) reacts with a functional group as a cross-linking starting point that reacts with a cross-linking agent, or with an ethylenically unsaturated group-containing compound to form an acrylic A functional group can be introduced that enables introduction of an ethylenically unsaturated group into the side chain of the system copolymer (A2).
The structural units derived from the functional group-containing monomers contained in the acrylic copolymer (A2) may be one type alone or two or more types.

Examples of functional group-containing monomers include the same hydroxyl group-containing monomers and carboxy group-containing monomers as the monomer (a2') described above. Among these, hydroxyl group-containing monomers are preferred, 2-hydroxyethyl (meth)acrylate is more preferred, and 2-hydroxyethyl acrylate is even more preferred.

The content of the structural unit derived from the functional group-containing monomer is preferably 1 to 40% by mass, more preferably 10 to 35% by mass, in all the structural units derived from the acrylic monomer constituting the acrylic copolymer (A2). %, more preferably 20 to 30 mass %.

The acrylic copolymer (A2) may contain, in addition to the above structural units, structural units derived from other monomers copolymerizable with acrylic monomers.
The structural units derived from other monomers contained in the acrylic copolymer (A2) may be of one type alone or two or more types.

The acrylic copolymer (A2) is preferably one into which an ethylenically unsaturated group is introduced in order to impart energy ray curability.
The ethylenically unsaturated group is, for example, a functional group of the acrylic copolymer (A2) containing a structural unit derived from a functional group-containing monomer, a reactive substituent having reactivity with the functional group, and an ethylenically unsaturated group. It can be introduced by reacting with a reactive substituent of a compound having a saturated group (hereinafter also referred to as "unsaturated group-containing compound"). The unsaturated group-containing compounds may be used singly or in combination of two or more.

Examples of the ethylenically unsaturated group possessed by the unsaturated group-containing compound include those mentioned above, and among these, a (meth)acryloyl group is preferred.
Examples of reactive substituents that the unsaturated group-containing compound has include an isocyanate group and a glycidyl group.
Examples of unsaturated group-containing compounds include 2-(meth)acryloyloxyethyl isocyanate, (meth)acryloylisocyanate, glycidyl (meth)acrylate and the like. Among these, 2-(meth)acryloyloxyethyl isocyanate is preferred, and 2-methacryloyloxyethyl isocyanate is more preferred.

When the acrylic copolymer (A2) containing structural units derived from functional group-containing monomers is reacted with the unsaturated group-containing compound, the total number of functional groups in the acrylic copolymer (A2) is The ratio of functional groups that react with the unsaturated group-containing compound is preferably 30 to 96 mol%, more preferably 60 to 94 mol%, still more preferably 80 to 92 mol%.
When the ratio of the functional group that reacts with the unsaturated group-containing compound is within the above range, it is easy to adjust the energy ray curability imparted to the acrylic copolymer (A2), and the unsaturated group-containing compound and The non-reacted functional groups can be reacted with a cross-linking agent to cross-link the acrylic copolymer (A2).

The mass average molecular weight (Mw) of the acrylic copolymer (A2) is preferably 200,000 to 1,500,000, more preferably 300,000 to 1,000,000, still more preferably 400,000 to 600,000.
When the mass average molecular weight (Mw) of the acrylic copolymer (A2) is within the above range, the adhesive strength and cohesive strength tend to be better.

The content of the acrylic copolymer (A2) in the adhesive composition (x-2) is preferably 60 with respect to the total amount (100% by mass) of the active ingredients in the adhesive composition (x-2). ~99% by mass, more preferably 70 to 95% by mass, still more preferably 80 to 90% by mass.

[Energy ray-curable compound]
The pressure-sensitive adhesive composition (x-2) may further contain an energy ray-curable compound other than the above components for the purpose of adjusting the cohesive force of the pressure-sensitive adhesive layer (X2).
The energy ray-curable compounds may be used singly or in combination of two or more.
Energy ray-curable compounds include, for example, monomers or oligomers that can be polymerized and cured by energy ray irradiation.
Examples of energy ray-curable compounds include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and 1,4-butylene glycol. Polyvalent (meth)acrylate monomers such as di(meth)acrylate and 1,6-hexanediol (meth)acrylate; urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, epoxy (meth)acrylate oligomers such as acrylate; Among these, urethane (meth)acrylate is preferred. Urethane (meth)acrylate is preferably polyfunctional urethane (meth)acrylate.
When the pressure-sensitive adhesive composition (x-2) contains an energy ray-curable compound, the content of the energy ray-curable compound is preferably 1 to 30 mass parts with respect to 100 parts by mass of the energy ray-polymerizable adhesive resin. parts, more preferably 5 to 20 parts by mass, still more preferably 8 to 15 parts by mass.

[Photopolymerization initiator]
The pressure-sensitive adhesive composition (x-2) preferably contains a photopolymerization initiator from the viewpoint of allowing the curing reaction to proceed sufficiently even when irradiated with relatively low-energy energy rays.
The photopolymerization initiator includes, for example, the same photopolymerization initiators mentioned in the description of the solvent-free resin composition (y-1a). Among these, 2,2-dimethoxy-2-phenylacetophenone is preferred.
A photoinitiator may be used individually by 1 type, and may use 2 or more types together.
The content of the photopolymerization initiator in the adhesive composition (x-2) is preferably 0.01 to 10 parts by mass, more preferably 0 parts by mass, with respect to 100 parts by mass of the total amount of the energy ray-polymerizable adhesive resin. 0.03 to 5 parts by mass, more preferably 0.05 to 3 parts by mass.

[Crosslinking agent]
When the energy ray-polymerizable adhesive resin further has a functional group other than the energy ray-polymerizable functional group, the adhesive composition (x-2) preferably further contains a cross-linking agent.
The cross-linking agent includes, for example, the same cross-linking agents as mentioned in the description of the pressure-sensitive adhesive composition (x-1). Among these, trimethylolpropane adduct-type modified polyisocyanate compounds are preferred, trimethylolpropane adduct-type modified aromatic polyisocyanate compounds are more preferred, and trimethylolpropane adduct-type modified tolylene diisocyanate is even more preferred. .
The content of the cross-linking agent in the pressure-sensitive adhesive composition (x-2) is appropriately adjusted according to the number of functional groups possessed by the energy-ray-polymerizable adhesive resin. 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and still more preferably 0.05 to 5 parts by mass.

[Tackifier]
The pressure-sensitive adhesive composition (x-2) may further contain a tackifier from the viewpoint of further improving the adhesive strength. The tackifier includes, for example, the same tackifiers mentioned in the description of the adhesive composition (x-1).

[Additive for adhesive]
The pressure-sensitive adhesive composition (x-2) may contain additives for pressure-sensitive adhesives used in general pressure-sensitive adhesives, in addition to the additives described above, within a range that does not impair the effects of the present invention. .
As the adhesive additive, for example, the same ones as the adhesive additive mentioned in the explanation of the adhesive composition (x-1) can be mentioned.

(Thickness of adhesive layer (X2))
The thickness of the pressure-sensitive adhesive layer (X2) is preferably 5-150 μm, more preferably 8-100 μm, even more preferably 12-70 μm, still more preferably 15-50 μm.
When the thickness of the pressure-sensitive adhesive layer (X2) is within the above range, there is a tendency that the workpiece can be well fixed.

<Total light transmittance of double-sided adhesive sheet>
As described above, in the production method of the present embodiment, when the pressure-sensitive adhesive layer (X2) is cured, it is difficult to be affected by the decrease in energy ray transmittance due to the expanded thermally expandable layer. Therefore, according to the manufacturing method of the present embodiment, for example, the content of the thermally expandable particles in the thermally expandable layer is high, or the thickness of the thermally expandable layer is large, and the energy generated by the thermally expandable layer after expansion Even in the case of using a double-sided PSA sheet with a large decrease in line transmittance, the PSA layer (X2) has a feature of obtaining good curability.
Therefore, a 1.1 mm thick glass plate made of soda-lime glass was placed on the adhesive layer (X2) of the double-sided adhesive sheet, which is an indicator of the energy ray transmittance of the double-sided adhesive sheet after the thermally expandable layer was expanded. The laminate for total light transmittance measurement (L _A ) obtained by heating the laminate for 1 minute at a temperature of expansion start temperature (t) of the thermally expandable particles + 22 ° C. Wavelength 380 nm in the thickness direction The total light transmittance (T _A ) of, for example, may be less than 60%, may be less than 50%, may be less than 40%, may be less than 30%, may be less than 20 %, may be less than 15%, or may be less than 10%.
Among the above ranges, even when the energy ray transmittance is greatly reduced by the thermally expandable layer after expansion, the characteristic of the production method of the present embodiment that good curability of the pressure-sensitive adhesive layer (X2) can be obtained is effective. From the viewpoint of effectively expressing the total light transmittance (T _A ) of the double-sided PSA sheet, it is preferable that the total light transmittance (T A ) of the double-sided PSA sheet is low. A double-sided PSA sheet having a light transmittance (T _A ) of less than 20% is used.
As the double-sided PSA sheet having a total light transmittance (T _A ) of less than 20%, as described above, the thermally expandable layer has a higher content of thermally expandable particles, or the thermally expandable layer has a higher content of thermally expandable particles. In addition to those having a large thickness, for example, a double-sided pressure-sensitive adhesive sheet when a material having low energy ray transmittance is selected for the substrate layer (Y) or the pressure-sensitive adhesive layer (X1) can be used.

<Method for producing double-sided adhesive sheet>
The method for producing the double-sided pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, and for example, the double-sided pressure-sensitive adhesive sheet can be produced by a method including a step of forming the pressure-sensitive adhesive layer (X1), a step of forming the pressure-sensitive adhesive layer (X2), and the like. . The order of these steps is not particularly limited, and they may be performed simultaneously.

The pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) constitute, for example, the pressure-sensitive adhesive composition (x-1) or the pressure-sensitive adhesive composition (x-2), the release sheet or the base layer (Y). It can be formed by coating on a substrate and then drying. When the pressure-sensitive adhesive layer (X1) is formed using a polymerizable composition, the polymerizable composition is applied onto a release sheet or a substrate constituting the substrate layer (Y), and then irradiated with energy rays. Thus, the pressure-sensitive adhesive layer (X1) can be formed.
Examples of methods for applying the adhesive composition (x-1) and the adhesive composition (x-2) include spin coating, spray coating, bar coating, knife coating, roll coating, and blade coating. method, die coating method, gravure coating method, and the like.

The pressure-sensitive adhesive layer (X1) or the pressure-sensitive adhesive layer (X2) formed on the release sheet is formed by, for example, attaching the pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive layer (X2) to each other according to the configuration of the desired double-sided pressure-sensitive adhesive sheet. Alternatively, the adhesive layer (X1) may be attached to one surface of the substrate and the adhesive layer (X2) may be attached to the other surface of the substrate.

Next, each step of the manufacturing method of this embodiment will be described with reference to FIGS.
3 to 9 show an embodiment in which a double-sided pressure-sensitive adhesive sheet 1c is used as a double-sided pressure-sensitive adhesive sheet, and a semiconductor wafer W, which is an object to be processed, is ground and singulated by a stealth dicing method. is not limited to the following embodiments.

<Step 1>
Step 1 is a process object attaching step of attaching a workpiece to the adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support attaching step of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. And, it is a step including.

In the manufacturing method of the present embodiment, the support is attached to the pressure-sensitive adhesive layer (X1) whose adhesion is greatly reduced by heating. As a result, even when the support is made of a hard material, the double-sided pressure-sensitive adhesive sheet and the support can be easily separated without bending the two.

(object to be processed)
Examples of workpieces include semiconductor chips, semiconductor wafers, compound semiconductors, semiconductor packages, electronic components, LED elements, sapphire substrates, glass substrates, displays, and panel substrates. Among these, the manufacturing method of the present embodiment is suitable for processing semiconductor wafers. Note that even materials that are insulators, such as sapphire and glass, and that do not directly affect the semiconductor characteristics of the semiconductor device can serve as objects to be processed in the present embodiment as long as they are used in the semiconductor device.
Examples of semiconductor wafers include silicon wafers; wafers of gallium arsenide, silicon carbide, lithium tantalate, lithium niobate, gallium nitride, indium phosphide, and the like.
The thickness of a semiconductor wafer before processing is typically 500-1,000 μm.

(support)
The material of the support may be appropriately selected depending on the type of object to be processed, the details of processing, etc., and considering the required properties such as mechanical strength and heat resistance.
Materials of the support include, for example, metallic materials such as SUS; nonmetallic inorganic materials such as glass and silicon wafers; epoxy resins, ABS resins, acrylic resins, engineering plastics, super engineering plastics, polyimide resins, polyamideimide resins, and the like. resin materials; compound materials such as glass epoxy resins; among these, SUS, glass, and silicon wafers are preferable.
Engineering plastics include, for example, nylon, polycarbonate (PC), polyethylene terephthalate (PET), and the like.
Super engineering plastics include, for example, polyphenylene sulfide (PPS), polyethersulfone (PES), polyetheretherketone (PEEK), and the like.
As will be described later, when the energy ray irradiation step is performed by irradiating the energy ray from the side of the support after the step of attaching the support in step 1 and before step 3, at least at any time, the support is A material having energy ray transparency is preferred. Examples of the support having energy ray transparency include glass and resin materials. On the other hand, examples of the support having low energy ray transmittance include metal materials and silicon wafers.

The support is preferably attached to the entire adhesive surface of the adhesive layer (X1). Therefore, the area of the surface of the support on the adhesive surface of the adhesive layer (X1) is preferably equal to or greater than the area of the adhesive surface of the adhesive layer (X1). Further, the surface of the support on the side to be attached to the adhesive surface of the adhesive layer (X1) is preferably planar.
Although the shape of the support is not particularly limited, it is preferably plate-like.
The thickness of the support may be appropriately selected in consideration of the required properties, preferably 20 μm or more and 50 mm or less, more preferably 60 μm or more and 20 mm or less.

FIG. 3 shows a cross-sectional view in which the semiconductor wafer W is attached to the adhesive layer (X2) of the double-sided adhesive sheet 1c, and the support 2 is attached to the adhesive layer (X1).
The semiconductor wafer W is attached so that the circuit surface W1 faces the adhesive layer (X2).

<Step 2>
Step 2 is a step of processing the surface of the object opposite to the surface attached to the pressure-sensitive adhesive layer (X2) while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet. is.

Step 2 preferably includes a step of performing one or more processes selected from grinding and singulation on the object to be processed (hereinafter also referred to as “shape processing step”), and grinds and singulates the object to be processed. It is more preferable to include the step of fragmenting.

As the shape processing process, for example, grinding processing using a grinder, etc.; singulation processing by blade dicing method, laser dicing method, plasma dicing method; blade tip dicing method (DBG; Dicing Before Grinding), stealth tip dicing method (SDBG) : Grinding and singulation by Stealth Dicing Before Grinding; Among these, grinding and singulation by a blade tip dicing method or a stealth tip dicing method are preferable.

In the blade tip dicing method, grooves are formed in advance on one surface of an object to be processed to a depth shallower than the thickness of the object to be divided lines. It is a method of separating into individual pieces. The grooves reached by the ground surface become cuts penetrating the object to be cut into pieces along the dividing line. The pre-formed grooves can be formed, for example, by dicing using a wafer dicing machine equipped with a dicing blade. If the workpiece is a semiconductor wafer, the grooves are formed in the circuit surface of the semiconductor wafer.

In the stealth dicing method, a modified region, which is a line to be divided, is formed inside an object to be processed such as a semiconductor wafer by irradiating it with a laser beam, and a grinding process is performed to make the object to be processed into pieces while thinning them. The method. Specifically, while the object to be processed having the modified region is ground and thinned, the pressure applied to the object at that time is applied to the adhesive layer of the object to be adhered with the modified region as a starting point. The crack is extended toward and the object to be processed is separated into individual pieces along the planned division line.
The grinding thickness after forming the modified region may be a thickness that reaches the modified region. It may be broken by processing pressure of a grinding wheel or the like.
The modified region is a portion embrittled by multiphoton absorption, and is formed by laser beam irradiation focused inside the object to be processed. The incident surface of the laser beam is not particularly limited, and the object may be irradiated with the laser beam through the double-sided adhesive sheet.

When step 2 includes a step of grinding and singulating the object, as a preliminary step for singulating the object, an adhesive layer ( X2) Forming a modified region, which is a line to be divided, inside the object before the step of forming a groove, which is a line to be divided, on the surface to be attached to X2), or the step of grinding and singulating. preferably further comprising the steps of: Then, in the step of grinding and singulating the object to be processed, the object to be processed is attached to the adhesive layer (X2) of the object to be processed in a state where the object is supported by the support via the double-sided adhesive sheet. It is preferable that the step is a step of grinding the surface on the opposite side of the surface and dividing the workpiece along the planned division lines with the grooves or the modified regions as starting points to individualize the workpiece.
The method for forming the groove and the method for forming the modified region are as described above.
The formation of the grooves is performed before attaching the workpiece to the double-sided pressure-sensitive adhesive sheet of the present embodiment.
On the other hand, the formation of the modified region may be performed before or after the object to be processed is attached to the double-sided pressure-sensitive adhesive sheet of the present embodiment. From the viewpoint that the object can be held on the support from the formation of the modified region to the separation into individual pieces, it is preferable to carry out the adhesion after the application.

In the manufacturing method of the present embodiment, when the object to be processed is ground, the thickness of the object to be processed after grinding is preferably 5 to 100 μm, more preferably 10 to 45 μm.
In the manufacturing method of the present embodiment, when chips are manufactured by singulating an object to be processed such as a semiconductor wafer, the size of the obtained chips in plan view is preferably less than 600 mm ² , more preferably less than 400 mm ² , More preferably less than 300 mm ² . In addition, planar view means seeing in a thickness direction.
The shape of the chip in plan view may be a square or an elongated shape such as a rectangle.

FIG. 4 shows a step of forming a plurality of modified regions 4 on the semiconductor wafer W adhered to the adhesive layer (X2) using the laser beam irradiation device 3. As shown in FIG.
A laser beam is irradiated from the back surface W2 side of the semiconductor wafer W, and a plurality of modified regions 4 are formed inside the semiconductor wafer W at substantially equal intervals.

5(a) and 5(b) show cross-sectional views for explaining the process of separating the semiconductor wafer W into a plurality of semiconductor chips CP while thinning it.
As shown in FIG. 5A, the rear surface W2 of the semiconductor wafer W on which the modified region 4 is formed is ground by a grinder 5. At this time, the pressure applied to the semiconductor wafer W cuts the semiconductor wafer W from the modified region 4 as a starting point. give rise to As a result, as shown in FIG. 5B, a plurality of semiconductor chips CP obtained by thinning and singulating the semiconductor wafer W are obtained. When grinding and singulating the semiconductor wafer W, the support 2 is preferably fixed on a fixed table such as a chuck table.

Step 2 includes, if necessary, a step of applying a semiconductor tape to the surface of the object opposite to the adhesive layer (X2) (hereinafter also referred to as a "semiconductor tape applying step"). good too.
Examples of semiconductor tapes include known semiconductor tapes such as die attach films and dicing tapes. Only one type of semiconductor tape may be applied, or two or more types may be applied.
The semiconductor tape is preferably attached to the surface of the object to be processed on the side opposite to the adhesive layer (X2) after the shape processing step. Later, it is more preferable to attach the adhesive layer (X2) to the surface of the individualized object opposite to the adhesive layer (X2).

FIG. 6 shows a cross-sectional view in which a thermosetting film 6 having a support sheet 7 is attached as a die attach film to the surface of a plurality of semiconductor chips CP opposite to the adhesive layer (X2). It is

<Energy beam irradiation process>
The manufacturing method of the present embodiment has an energy ray irradiation step at least at some time after the step of sticking an object to be processed in Step 1 and before Step 3.
In the energy ray irradiation step, the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet is irradiated with energy rays to cure the pressure-sensitive adhesive layer (X2). The semiconductor wafer, which is the object to be processed, itself has low energy ray transparency, or even if it has energy ray transparency, the energy ray is transmitted by the circuit wiring, electrodes, etc. provided on the object to be processed. Permeation is blocked. Therefore, the double-sided pressure-sensitive adhesive sheet is irradiated with energy rays so as to face the surface opposite to the surface to which the object to be processed is attached. In the production method of the present embodiment, since the energy beam irradiation step is performed before step 3, the energy beam irradiated toward the adhesive layer (X2) can be applied to the adhesive even through the thermally expandable layer. It is possible to reach layer (X2).
The energy beam irradiation step may be performed only once, or may be performed in multiple steps.

The timing of performing the energy ray irradiation step is not particularly limited as long as it is after the process of attaching the workpiece in Step 1 and before Step 3, and examples thereof include the following timings (a) to (c).
(a) after the step of attaching the workpiece in step 1 and at least at any time before step 2 (b) at any time within step 2 (c) after step 2 and step 3 Before

When performing the energy beam irradiation step at the time (a), even if the blade tip dicing method or the stealth tip dicing method is adopted, the semiconductor wafer W is still singulated into a plurality of semiconductor chips CP in the energy beam irradiation step. It has not been. When the energy beam irradiation step is performed after the semiconductor wafer W is singulated into a plurality of semiconductor chips CP, the energy beams pass through the gaps between the plurality of semiconductor chips CP and the semiconductor tape is irradiated with the energy beams. If the adhesive has energy ray reactivity, the reaction may proceed. This may cause problems such as peeling of the plurality of semiconductor chips CP from the semiconductor tape. Such a problem can be prevented by selecting the timing (a) as the timing for performing the energy beam irradiation step. For the period (a), more specifically, at least one of the following periods (a1) to (a3) can be selected according to the order of processing performed in step 1.
(a1) In the case where step 1 is a step of performing the support sticking step after the work object sticking step, (a2) step 1 after the work object sticking step and before the support sticking step , in the case of the step of performing the support sticking step after the work object sticking step, after the support sticking step and before step 2 (a3), step 1 is after the support sticking step or the supporting step. After the step of attaching the object to be processed and before step 2 in the case of performing the step of attaching the object to be processed at the same time as the body attaching step

For the period (b), more specifically, at least one of the following periods (b1) and (b2) can be selected according to the processing performed in step 2.
(b1) When step 2 includes a singulation preliminary step, after the singulation preliminary step and before subsequent grinding and singulation, (b2) step 2 includes a shape processing step and a shape processing step. After the shape processing step and before the semiconductor tape applying step when the subsequent semiconductor tape applying step is included

When step 2 includes a step of grinding the object to be processed as a shape processing step, and the energy beam irradiation step is performed during at least one of the periods (a) and (b1), i.e., grinding the object to be processed. When the energy beam irradiation step is performed before the step, the pressure-sensitive adhesive layer (X2) attached to the object is hardened and has a high elastic modulus when the object is ground. Therefore, sinking, vibration, movement, etc. of the object to be processed during grinding can be effectively suppressed, and the machining accuracy of the object to be processed can be improved. Specifically, it is possible to suppress variations in the thickness of the workpiece thinned by grinding, chipping during singulation, and the like.
On the other hand, as the timing (c), for example, even when the energy beam irradiation step is performed after the step 2 is completed and before the transportation for performing the step 3, the vibration caused by the cured adhesive layer (X2) during transportation can be effectively suppressed, so damage to the workpiece can be suppressed.
The adhesive layer (X2) is reduced in adhesive strength by performing the energy beam irradiation step, but it is sufficient for processing in which force is applied in the shearing direction or the pressing direction, such as grinding and singulation. can exert a strong holding power.

Further, when the energy ray irradiation step is performed during the period (a1), since the support is not attached during the energy ray irradiation, a support having low energy ray transmittance can be selected.
When all the layers other than the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet and the support have energy ray transparency, the energy ray irradiation step is performed after the support attachment step of step 1. , and at least some time before step 3, energy rays may be irradiated from the support side.

Although the pressure-sensitive adhesive layer (X2) is cured by irradiation with energy rays, the thermally expandable particles of the thermally expandable layer may unintentionally expand due to reaction heat or the like generated at that time. In particular, when a semiconductor tape is applied to an object to be processed by the above-described semiconductor tape applying step, a heat having a low expansion start temperature (t) is used to suppress thermal change of the semiconductor tape during thermal peeling. Expandable particles may be used. In that case, the unintended expansion described above tends to occur easily.
A double-sided PSA sheet with expanded thermally expandable particles may unintentionally peel off from the support before step 3. In addition, the degree of expansion of the thermally expandable particles may become uneven depending on the area, making it difficult to process. In some cases, the thickness accuracy of the object after grinding is lowered, and cracks, chipping, etc., may occur in the object to be processed. In addition, when performing the singulation preliminary step, non-uniformity in the thickness of the double-sided pressure-sensitive adhesive sheet may affect the accuracy of the laser irradiation position.
From this point of view, in the production method of the first aspect of the present invention, in the energy beam irradiation step, the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet is irradiated with energy beams without expanding the thermally expandable particles to produce the pressure-sensitive adhesive. It has a step of curing the layer (X2), and in the production method of the second aspect of the present invention, in the energy beam irradiation step, the temperature of the thermally expandable layer is the expansion start temperature (t) of the thermally expandable particles. A step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with energy rays to cure the pressure-sensitive adhesive layer (X2) so as not to exceed a temperature lower than 5°C.
In addition, in the production method of the first aspect of the present invention, the fact that the thermally expandable particles are not expanded can be confirmed, for example, by the fact that the thickness of the thermally expandable layer does not change before and after the energy beam irradiation step. can.
Further, in the production method of the second aspect of the present invention, the temperature not exceeding 5 ° C. lower than the expansion start temperature (t) of the thermally expandable particles is, for example, the [Energy beam irradiation step during the energy beam irradiation step of the example described later. Temperature Measurement of Adhesive Sheet].

Methods for suppressing the expansion of the thermally expandable particles during the energy beam irradiation step include, for example, a method of performing the energy beam irradiation step while cooling the double-sided adhesive sheet, a method of adjusting the light intensity of the energy beam, and the like. is mentioned.

Examples of the method of performing cooling while performing cooling include, for example, a method in which the cooling is performed by lowering the temperature of the atmosphere in which the double-sided pressure-sensitive adhesive sheet exists, and a method in which a heat conductor is directly or indirectly added to the double-sided pressure-sensitive adhesive sheet as the cooling. Examples include a method of performing a process of bringing them into contact with each other.

The step of irradiating an energy ray, in which the temperature of the atmosphere in which the double-sided pressure-sensitive adhesive sheet exists is lowered, is a step performed in a chamber filled with gas, and a step satisfying the following requirement (I) or (II). preferable.
(I) The energy beam irradiation step is a step of replacing at least part of the gas filled in the chamber with gas supplied from outside the chamber during the energy beam irradiation step.
(II) In the energy beam irradiation step, a cycle of irradiating one double-sided pressure-sensitive adhesive sheet with an energy beam and then starting irradiation of another double-sided pressure-sensitive adhesive sheet with an energy beam is repeated to obtain a plurality of double-sided pressure-sensitive adhesive sheets. A step of sequentially irradiating the sheet with an energy beam, wherein the repeated cycle includes irradiating the one double-sided pressure-sensitive adhesive sheet with an energy beam, and then irradiating the other double-sided pressure-sensitive adhesive sheet with the energy beam in at least one cycle. At least a part of the gas filled in the chamber is replaced with gas supplied from outside the chamber before starting to irradiate the sheet with energy rays.

By satisfying the requirement (I) or (II), the temperature of the atmosphere in the chamber can be lowered, thereby cooling the double-sided PSA sheet.
The gas inside the chamber and the gas supplied from outside the chamber may be air or an inert gas such as nitrogen or argon. A gas is preferred, and nitrogen is more preferred.
The temperature of the gas supplied from outside the chamber may be lower than the temperature of the atmosphere inside the chamber, and may be, for example, room temperature or may be cooled below room temperature.
In the requirement (I) above, gas replacement may be performed continuously or intermittently during energy beam irradiation.
In the above requirement (II), the timing of the gas replacement cycle is not particularly limited, and may be performed periodically, or may be performed irregularly depending on the temperature of the atmosphere in the chamber. It is preferable to do this every time.

As the energy beam irradiation step in which the heat conductor is directly or indirectly brought into contact with the double-sided pressure-sensitive adhesive sheet, for example, the pressure-sensitive adhesive layer (X2) of the object to be processed attached to the pressure-sensitive adhesive layer (X2) is A step of irradiating the energy beam with a heat conductor in contact with the opposite surface is preferred.
In order to enhance the cooling effect, the heat conductor may have an artificial cooling mechanism such as circulating a coolant inside, or it may not have an artificial cooling mechanism. good too. Even if the heat conductor itself is not intentionally cooled, the heat absorbed from the contact surface with the double-sided pressure-sensitive adhesive sheet can be naturally radiated from the surface of the heat conductor itself, thereby producing a cooling effect. Although the material of the heat conductor is not particularly limited, metals such as copper, aluminum, iron, and stainless steel are preferable from the viewpoint of thermal conductivity. Further, heat radiation means such as heat radiation fins may be provided.

As a method for adjusting the light intensity of the energy beam, for example, depending on the type of energy beam and the structure of the double-sided pressure-sensitive adhesive sheet, the light intensity may be appropriately selected so that the temperature of the double-sided pressure-sensitive adhesive sheet is within a range in which the thermally expandable particles do not expand. Just do it.
For example, when ultraviolet light is used as the energy beam, the amount of light at a wavelength of 365 nm is preferably 50 to 1,000 mJ/cm ² from the viewpoint of curing the pressure-sensitive adhesive layer (X2) while suppressing temperature rise of the double-sided pressure-sensitive adhesive sheet. , more preferably 100 to 900 mJ/cm ² , still more preferably 300 to 850 mJ/cm ² .
In addition, if necessary, the temperature rise of the double-sided pressure-sensitive adhesive sheet can be suppressed by performing energy beam irradiation in multiple times.

When ultraviolet rays are used as energy rays, for example, electrodeless lamps, high-pressure mercury lamps, metal halide lamps, LED-UV, and the like can be used as ultraviolet light sources. Among these, LED-UV is preferable from the viewpoint that it is easy to suppress the temperature rise of the double-sided pressure-sensitive adhesive sheet.
Moreover, when using a reflector when irradiating an ultraviolet-ray, as a reflector, well-known reflectors, such as an aluminum mirror and a cold mirror, can be used, for example. Among these, a cold mirror is preferable from the viewpoint that it is easy to suppress the temperature rise of the double-sided pressure-sensitive adhesive sheet. However, when using an ultraviolet light source such as LED-UV, which has excellent straightness, the reflector may not be used.

Two or more methods for suppressing the expansion of the thermally expandable particles during the energy beam irradiation step may be employed in combination. For example, the light intensity of the energy rays may be adjusted while performing a process of lowering the temperature of the atmosphere in which the double-sided pressure-sensitive adhesive sheet exists.
It is preferable to suppress the temperature rise of the thermally expandable layer by adopting these means, etc., but the temperature of the thermally expandable layer preferably does not exceed 70°C, more preferably does not exceed 60°C. By carrying out the steps, for example, when thermally expandable particles having an expansion start temperature (t) of 75 to 105° C. are used, expansion of the thermally expandable particles can be efficiently suppressed. The temperature of the thermally expandable layer during energy beam irradiation is usually maintained at 5°C or higher, preferably 10°C or higher.

<Step 3>
Step 3 is a step of heating the double-sided pressure-sensitive adhesive sheet to the expansion start temperature (t) of the thermally expandable particles or higher to separate the pressure-sensitive adhesive layer (X1) from the support.
FIG. 7 shows a cross-sectional view for explaining the process of heating the double-sided pressure-sensitive adhesive sheet 1c to separate the pressure-sensitive adhesive layer (X1) from the support 2. As shown in FIG.

The heating temperature in step 3 is equal to or higher than the expansion start temperature (t) of the thermally expandable particles, preferably "a temperature higher than the expansion start temperature (t)", more preferably "expansion start temperature (t) + 2°C" or higher. More preferably, it is "expansion start temperature (t) + 4°C" or higher, and still more preferably "expansion start temperature (t) + 5°C" or higher.
In addition, the heating temperature in step 3 is preferably “expansion start temperature (t) + 50 ° C.” or less, more preferably “expansion start temperature ( t) + 40°C" or less, more preferably "expansion start temperature (t) + 20°C" or less.
From the viewpoint of suppressing thermal change of the object to be processed, the heating temperature in step 3 is preferably less than 125°C, more preferably 120°C or less, and still more preferably 115°C within a range equal to or higher than the expansion start temperature (t). Below, more preferably 110° C. or less, still more preferably 105° C. or less.

<Step 4>
Step 4 is a step of separating the pressure-sensitive adhesive layer (X2) and the object to be processed.
Since the pressure-sensitive adhesive layer (X2) is cured by the energy ray irradiation process and its adhesive strength is lowered, it can be easily peeled off from the object to be processed by a known peeling means.

FIG. 8 shows a cross-sectional view for explaining the step of separating the adhesive layer (X2) and the plurality of semiconductor chips CP.
The obtained thermosetting film 6 to which the plurality of semiconductor chips CP are attached is preferably divided into the same shape as the semiconductor chips CP to obtain the semiconductor chips CP with the thermosetting film 6 . As a method for dividing the thermosetting film 6, for example, a method such as laser dicing using a laser beam, expansion, or fusion cutting can be applied.
FIG. 9 shows semiconductor chips CP with thermosetting films 6 that are divided on the support sheet 7 in the same shape as the semiconductor chips CP.

The semiconductor chip CP with the thermosetting film 6 on the support sheet 7 is further subjected to an expansion process or the like for widening the gap between the semiconductor chips CP as necessary, and then picked up and placed on the thermosetting film 6 side. is attached (die attached) to the substrate from the After that, the semiconductor chip CP and the substrate can be fixed by thermosetting the thermosetting film 6 .

The present invention will be specifically described by the following examples, but the present invention is not limited to the following examples. In addition, the physical property value in each example is the value measured by the following method.

[Mass average molecular weight (Mw)]
Using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020"), measurement was performed under the following conditions, and the values measured in terms of standard polystyrene were used.
(Measurement condition)
・ Column: "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", "TSK gel G1000HXL" (both manufactured by Tosoh Corporation) are sequentially connected ・Column temperature: 40 ° C.
・Developing solvent: tetrahydrofuran ・Flow rate: 1.0 mL/min

[Thickness of each layer]
It was measured at 23° C. using a constant pressure thickness measuring instrument manufactured by Teclock Co., Ltd. (model number: “PG-02J”, standard specifications: conforming to JIS K6783, Z1702, Z1709).

[Average particle size (D ₅₀ ) and 90% particle size (D ₉₀ ) of thermally expandable particles]
Using a laser diffraction particle size distribution analyzer (for example, manufactured by Malvern, product name "Mastersizer 3000"), the particle distribution of the thermally expandable particles before expansion at 23 ° C. is measured, and the particle size of the particle distribution is small. The particle diameters corresponding to the cumulative volume frequencies of 50% and 90% calculated from the method are defined as the "average particle diameter of the thermally expandable particles ( _D50 )" and the "90% particle diameter of the thermally expandable particles ( _D90 ), respectively. "

[Storage elastic modulus E′ (23) at 23° C. of the non-thermally expandable base layer (Y2)]
Using a non-thermally expandable base material layer (Y2) cut to 30 mm long and 5 mm wide as a test sample, using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name "DMAQ800"), the test start temperature The storage elastic modulus E′ at 23° C. was measured under the conditions of 0° C., test end temperature of 200° C., temperature increase rate of 3° C./min, frequency of 1 Hz, and amplitude of 20 μm. As a result, the storage elastic modulus E′(23) at 23° C. of the PET film, which is the non-thermally expandable base layer (Y2) described later, was 2.27×10 ⁹ Pa.

[Method for measuring total light transmittance at a wavelength of 380 nm in the thickness direction]
The transmission spectrum of each measurement sample was measured under the following conditions to obtain the total light transmittance at a wavelength of 380 nm in the thickness direction.
<Measurement conditions>
Measurement wavelength range: 200-800nm
Measurement temperature: 23°C
Measurement atmosphere: air Measurement device: UV-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, product name "UV-3600") equipped with an integrating sphere accessory (manufactured by Shimadzu Corporation, product name "ISR-3100") ”)

[Temperature measurement of adhesive sheet during energy beam irradiation process]
For the purpose of finding energy ray irradiation conditions suitable for the manufacturing method of the present embodiment, an investigation was made on the temperature rise due to energy ray irradiation of the energy ray-curable pressure-sensitive adhesive layer.

Reference example 1
A semiconductor processing sheet "D-675" manufactured by Lintec Corporation was attached as a single-sided adhesive sheet having an ultraviolet curable adhesive layer to a 12-inch standard silicon wafer and ring frame. A thermocouple for temperature measurement was placed on the surface of the pressure-sensitive adhesive sheet opposite to the surface bonded to the silicon wafer. The installation position of the thermocouple was set at the center of the circular adhesive sheet in plan view of the adhesive sheet. Next, using "RAD-2010m/12" manufactured by Lintec Co., Ltd. as an ultraviolet irradiation device, the pressure-sensitive adhesive sheet is irradiated with ultraviolet rays at an illuminance of 230 mW/cm ² at a wavelength of 365 nm and a light amount (at a wavelength of 365 nm) shown in Table 1. After that, the temperature of the adhesive sheet was measured. The UV lamp attached to the ultraviolet irradiation device was a high-pressure mercury lamp, and the reflector was an aluminum mirror.

Reference example 2
In Reference Example 1, the pressure-sensitive adhesive sheet was irradiated with ultraviolet rays and the temperature of the pressure-sensitive adhesive sheet was measured in the same manner as in Reference Example 1, except that the reflector was changed to a cold mirror. Table 1 shows the results.

Reference example 3
In Reference Example 1, the procedure was the same as in Reference Example 1, except that the ultraviolet irradiation device was changed to an LED-UV lamp having a selective light intensity at 365 nm, and the illuminance was changed to 2,000 mW/cm ² . The pressure-sensitive adhesive sheet was irradiated with ultraviolet rays, and the temperature of the pressure-sensitive adhesive sheet was measured. Note that the LED-UV lamp does not have a reflector because the emitted ultraviolet rays travel straight. Table 1 shows the results.

From Table 1, it can be seen that the temperature of the adhesive sheet increases as the amount of ultraviolet light irradiated to the energy ray-curable adhesive layer increases. Further, by comparing Reference Examples 1 to 3, it can be seen that the cold mirror suppresses the temperature rise of the adhesive sheet more than the aluminum mirror, and the LED-UV lamp suppresses the temperature rise more than the high-pressure mercury lamp.

[Production of double-sided pressure-sensitive adhesive sheet and measurement of total light transmittance]
Next, a double-sided pressure-sensitive adhesive sheet that can be used in the manufacturing method of the present embodiment was manufactured, and the influence on the total light transmittance when the thermally expandable layer of the double-sided pressure-sensitive adhesive sheet was expanded was investigated.
The details of the materials used to manufacture the double-sided pressure-sensitive adhesive sheet 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) solution containing an acrylic copolymer with Mw of 600,000, diluent solvent: ethyl acetate, solid content concentration: 40 mass%
・Acrylic copolymer (A2): A structure derived from a raw material monomer consisting of n-butyl acrylate (BA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) = 52/20/28 (mass ratio) An acrylic copolymer having a unit is reacted with 2-methacryloyloxyethyl isocyanate (MOI) so that the addition rate to all hydroxyl groups in the acrylic copolymer is 90% on a molar basis, Mw 500,000 Solution containing energy ray-curable acrylic copolymer, dilution solvent: ethyl acetate, solid content concentration: 35% by mass

(crosslinking agent)
· Isocyanate-based cross-linking agent (i): manufactured by Tosoh Corporation, product name "Coronate (registered trademark) HX", isocyanurate-type modified form of hexamethylene diisocyanate, solid content concentration: 100% by mass
· Isocyanate cross-linking agent (ii): manufactured by Tosoh Corporation, product name "Coronate (registered trademark) L", solution containing trimethylolpropane-modified tolylene diisocyanate, solid content concentration: 75% by mass

(Energy ray-curable compound)
・ Energy ray-curable compound (i): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name “Shikou UT-4332”, polyfunctional urethane acrylate

(Photoinitiator)
- Photoinitiator (i): bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide - Photoinitiator (ii): 1-hydroxycyclohexylphenyl ketone

(Additive)
・Phthalocyanine pigment

(Thermal expandable particles)
・Thermal expandable particles: manufactured by Nouryon, 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 size ( _D90 ) = 26.2 µm

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

<Production of double-sided adhesive sheet>
Production example 1
(Formation of adhesive layer (X1))
To 100 parts by mass of the solid content of the acrylic copolymer (A1), 0.74 parts by mass of the isocyanate cross-linking agent (i) (solid content ratio) is blended, diluted with toluene, stirred uniformly, and the active ingredient A pressure-sensitive adhesive composition (x-1) having a concentration of 25% by mass was prepared. Then, on the release surface of the heavy release film, the adhesive composition (x-1) is applied to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to form a 5 μm thick adhesive layer. (X1) was formed.

(Formation of adhesive layer (X2))
To 100 parts by mass of the solid content of the acrylic copolymer (A2), 12 parts by mass of the energy ray-curable compound (i) (solid content ratio), and 1.1 parts by mass of the isocyanate cross-linking agent (ii) (solid content ratio) , Photopolymerization initiator (i) 1 part by mass (solid content ratio) was blended, diluted with toluene, and stirred uniformly to prepare an adhesive composition (x-2) having an active ingredient concentration of 30% by mass. . Then, the adhesive composition (x-2) is applied to the release surface of the light release film to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to form a 20 μm thick adhesive layer. (X2) was formed.

(Formation of substrate laminate by laminating thermally expandable substrate layer (Y1) and non-thermally expandable substrate layer (Y2))
A terminal isocyanate urethane prepolymer obtained by reacting an ester diol and isophorone diisocyanate (IPDI) is reacted with 2-hydroxyethyl acrylate to form an oligomer having a mass average molecular weight (Mw) of 5,000 at both ends. A linear urethane prepolymer having an ethylenically unsaturated group (an oligomer having an ethylenically unsaturated group) was obtained.
Then, to 40 parts by mass (solid content ratio) of the urethane prepolymer synthesized above, 40 parts by mass (solid content ratio) of isobornyl acrylate (IBXA) and phenylhydroxypropyl acrylate (HPPA) are added as energy ray-polymerizable monomers. 20 parts by mass (solid content ratio) are blended, and 20 parts by mass of cyclohexyl acrylate (CHA) (solid content ratio), 2.0 parts by mass of photopolymerization initiator (ii) (solid content ratio), and as additives , and 0.2 parts by mass (solid content ratio) of a phthalocyanine pigment were blended to prepare an energy ray-curable composition.
Then, thermally expandable particles are added to the energy ray-curable composition so that the content of the thermally expandable particles is 30% by mass with respect to the total mass (100% by mass) of the resulting thermally expandable substrate layer (Y1). A solvent-free resin composition (y-1a) was prepared by blending and containing no solvent.

Next, a PET film (manufactured by Toyobo Co., Ltd., product name “Cosmoshine (registered trademark) A4300”, thickness: 50 μm) was prepared as a non-thermally expandable base layer (Y2). The non-solvent resin composition (y-1a) was applied to one side of the PET film so that the thermally expandable substrate layer (Y1) formed had a thickness of 100 μm to form a coating film.
Then, using an ultraviolet irradiation device (manufactured by Eyegraphics Co., Ltd., product name “ECS-401GX”) and a high-pressure mercury lamp (manufactured by Eyegraphics Co., Ltd., product name “H04-L41”), an illuminance of 160 mW / cm ² , and irradiated with ultraviolet rays under the conditions of a light amount of 500 mJ / cm ² to cure the coating film, and the thermally expandable base layer (Y1) was formed on the PET film as the non-thermally expandable base layer (Y2). A substrate laminate was obtained. The above illuminance and light amount during ultraviolet irradiation are values measured using an illuminance/photometer (manufactured by EIT, product name “UV Power Puck II”).

(Formation of double-sided adhesive sheet with release material)
The adhesive surface of the adhesive layer (X1) formed above and the surface of the thermally expandable substrate layer (Y1) of the substrate laminate were bonded together. Next, the adhesive surface of the adhesive layer (X2) formed above and the surface of the PET film of the substrate laminate were bonded together.
As a result, a double-sided pressure-sensitive adhesive sheet with a release material having the following structure was produced.
<Heavy Release Film>/<Adhesive Layer (X1), Thickness: 5 μm>/<Thermal Expandable Base Layer (Y1), Thickness: 100 μm>/<Non-thermally Expandable Base Layer (Y2), Thickness Thickness: 50 μm>/<Adhesive layer (X2), thickness: 20 μm>/<Light release film>

<Measurement of total light transmittance (T _A ) and (T _B )>
The light release film was removed from the adhesive layer (X2) of the double-sided adhesive sheet with a release material obtained in Production Example 1, and a glass plate (soda lime glass, Thickness 1.1 mm) using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., product name “V-130”) and pressed for 30 seconds at 60 ° C. and 0.2 MPa to attach the adhesive layer. By removing the heavy release film from (X1), a laminate for total light transmittance measurement (L _B ) in which a double-sided pressure-sensitive adhesive sheet before thermal expansion and a glass plate were laminated was produced.
In addition, the laminate for total light transmittance measurement (L _B ) prepared in the same manner as above was heated so that the glass plate was on the side in contact with the hot plate and the double-sided adhesive sheet was on the side not in contact with the hot plate. It was placed on a plate and heated at 110° C. (that is, 88° C.+22° C., which is the expansion start temperature (t) of the thermally expandable particles) for 1 minute. Thus, a laminate for total light transmittance measurement (L _A ) in which the thermally expanded double-sided pressure-sensitive adhesive sheet and the glass plate were laminated was produced.
Using the laminate for total light transmittance measurement (L _A ) and the laminate for total light transmittance measurement (L _B ) prepared above as measurement samples, under the above conditions, the light incident surface is the pressure-sensitive adhesive layer (X1 ) side, the total light transmittance at a wavelength of 380 nm in the thickness direction of the double-sided pressure-sensitive adhesive sheet was measured. As a result, the value of the total light transmittance (T _B ) of the laminate for total light transmittance measurement (L _B ) in which the double-sided pressure-sensitive adhesive sheet and the glass plate before thermal expansion were laminated was 40.1%. The value of the total light transmittance (T A ) of the laminate for total light transmittance measurement (L _A ) in which the double-sided pressure-sensitive adhesive sheet and the glass plate were laminated after expansion was 15.2 _% .
From the above results, it can be seen that the double-sided pressure-sensitive adhesive sheet of Production Example 1 has a significantly reduced UV transmittance after being peeled off by heating. Therefore, even if the pressure-sensitive adhesive layer (X2) is irradiated with ultraviolet rays through the thermally expandable layer after the thermal peeling, it is difficult to sufficiently cure the pressure-sensitive adhesive layer (X2).
On the other hand, in the production method of the present embodiment, even when using a double-sided pressure-sensitive adhesive sheet, such as the double-sided pressure-sensitive adhesive sheet obtained in Production Example 1, in which the UV transmittance is greatly reduced after being peeled off by heating, the pressure-sensitive adhesive layer (X2) Since the expansion of the thermally expandable layer is suppressed when the adhesive layer (X2) is irradiated with ultraviolet rays, it is possible to sufficiently cure the pressure-sensitive adhesive layer (X2).

1a, 1b, 1c double-sided adhesive sheet 2 support 3 laser beam irradiation device 4 modified region 5 grinder 6 thermosetting film 7 support sheet W semiconductor wafer W1 circuit surface of semiconductor wafer W2 back surface of semiconductor wafer CP semiconductor chip (X1) Adhesive layer (X1)
(X2) Adhesive layer (X2)
(Y) Base layer (Y)
(Y1) Thermally expandable base layer (Y1)
(Y2) Non-thermally expandable base layer (Y2)

Claims

At least having an adhesive layer (X1) as an outer layer on one side and an adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
Using a double-sided pressure-sensitive adhesive sheet in which at least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method of manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy ray irradiation step: A step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2) without expanding the thermally expandable particles.
At least having an adhesive layer (X1) as an outer layer on one side and an adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
Using a double-sided pressure-sensitive adhesive sheet in which at least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method of manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy beam irradiation step: the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet so that the temperature of the thermally expandable layer does not exceed a temperature lower than the expansion start temperature (t) of the thermally expandable particles by 5°C. The step of curing the pressure-sensitive adhesive layer (X2) by irradiating with an energy ray
A double-sided pressure-sensitive adhesive sheet having at least a pressure-sensitive adhesive layer (X1) as an outer layer on one side and a pressure-sensitive adhesive layer (X2) as an outer layer on the other side,
The pressure-sensitive adhesive layer (X2) is an energy ray-curable pressure-sensitive adhesive layer,
At least one of the layers other than the pressure-sensitive adhesive layer (X2) is a thermally expandable layer containing thermally expandable particles,
A laminate obtained by laminating a glass plate made of soda lime glass and having a thickness of 1.1 mm on the adhesive layer (X2) of the double-sided adhesive sheet was placed at a temperature of 22°C + the expansion start temperature (t) of the thermally expandable particles. Using a double-sided adhesive sheet having a total light transmittance (T A ) at a wavelength of 380 nm in the thickness direction of the laminate for total light transmittance measurement (L A ) obtained by heating for 1 minute at a temperature of less than 20%,
Having the following steps 1 to 4 in this order,
Step 1: A process object attaching step of attaching an object to be processed to the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet, and a support of attaching a support to the pressure-sensitive adhesive layer (X1) of the double-sided pressure-sensitive adhesive sheet. Step 2: Processing the object while the object is supported by the support via the double-sided pressure-sensitive adhesive sheet Step 3: Attaching the double-sided pressure-sensitive adhesive sheet to the A step of separating the pressure-sensitive adhesive layer (X1) and the support by heating to the expansion start temperature (t) of the thermally expandable particles or higher Step 4: separating the pressure-sensitive adhesive layer (X2) and the object to be processed Separating step A method for manufacturing a semiconductor device, comprising the following energy ray irradiation step after step 1 of attaching an object to be processed and before step 3 at least at any time.
Energy ray irradiation step: a step of irradiating the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet with an energy ray to cure the pressure-sensitive adhesive layer (X2)
The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the energy beam irradiation step is performed while cooling the double-sided adhesive sheet.
4. The energy beam irradiation step according to any one of claims 1 to 3, wherein the step is performed in a chamber filled with gas and satisfies the following requirements (I) or (II): and a method for manufacturing a semiconductor device.
(I) The energy beam irradiation step is a step of replacing at least part of the gas filled in the chamber with gas supplied from outside the chamber during the energy beam irradiation step.
(II) The energy ray irradiation step further repeats a cycle of irradiating one double-sided pressure-sensitive adhesive sheet with an energy ray and then starting irradiation of another double-sided pressure-sensitive adhesive sheet with an energy ray to obtain a plurality of double-sided pressure-sensitive adhesive sheets. A step of sequentially irradiating the adhesive sheet with energy rays,
The repeated cycle is
In at least one cycle, after irradiating the one double-sided pressure-sensitive adhesive sheet with an energy ray and before starting irradiation of the energy ray on the other double-sided pressure-sensitive adhesive sheet, the gas filled in the chamber is replaced with gas supplied from outside the chamber.
The step 2 includes grinding the workpiece,
4. Any one of claims 1 to 3, wherein the energy beam irradiation step is performed at least at any time after the step of attaching the workpiece in step 1 and before the step of grinding the workpiece. A method for manufacturing the semiconductor device according to the above item.
The step 1 is a step of performing the support attaching step after the process object attaching step,
4. The method of manufacturing a semiconductor device according to claim 1, wherein said energy ray irradiation step is performed after said object attachment step and before said support attachment step.
All layers other than the pressure-sensitive adhesive layer (X2) of the double-sided pressure-sensitive adhesive sheet and the support have energy ray transparency,
Claims 1 to 1, wherein the energy ray irradiation step is performed by irradiating an energy ray from the side of the support at least some time after the step 1 of attaching the support and before the step 3. 4. The method for manufacturing a semiconductor device according to any one of 3.
The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the thermally expandable particles have an expansion start temperature (t) of 50°C or higher and lower than 125°C.
The double-sided pressure-sensitive adhesive sheet further has a base layer (Y), and has the pressure-sensitive adhesive layer (X1), the base layer (Y), and the pressure-sensitive adhesive layer (X2) in this order. 4. The method of manufacturing a semiconductor device according to claim 1.
11. The method of manufacturing a semiconductor device according to claim 10, wherein at least one of said adhesive layer (X1) and said base material layer (Y) is said thermally expandable layer.
The step 2 includes a step of grinding and singulating the workpiece,
As a preliminary step for singulation of the object to be processed,
A step of forming a groove as a dividing line on the surface of the object to be processed that is attached to the adhesive layer (X2) before the step of grinding and singulating, or the grinding and singulation a step of forming a modified region, which is a line to be divided, inside the object before the step of converting,
The step of grinding and singulating the object to be processed is performed on the adhesive layer (X2) of the object to be processed in a state in which the object to be processed is supported by the support via the double-sided adhesive sheet. It is a step of grinding the surface opposite to the surface to which it is attached, and dividing the workpiece along the planned division lines with the groove or the modified region as a starting point to separate the object into individual pieces. 4. The method for manufacturing a semiconductor device according to any one of 1 to 3.