CN112262459A

CN112262459A - Method for manufacturing cured sealing body

Info

Publication number: CN112262459A
Application number: CN201980038938.3A
Authority: CN
Inventors: 山田忠知; 田久真也
Original assignee: Lintec Corp
Current assignee: Lintec Corp
Priority date: 2018-06-08
Filing date: 2019-05-22
Publication date: 2021-01-22
Also published as: TWI816796B; JPWO2019235217A1; WO2019235217A1; TW202000822A; JP7267272B2; KR20210018272A

Abstract

The present invention relates to a method for producing a cured seal, which is a method for producing a cured seal using a pressure-sensitive adhesive sheet having a base material (Y) provided with an expandable base material layer (Y1) containing expandable particles and a non-expandable base material layer (Y2), a1 st pressure-sensitive adhesive layer (X1), and a 2 nd pressure-sensitive adhesive layer (X2), wherein the method for producing a cured seal comprises the following steps (1) to (3), and (1): a step of adhering the adhesive surface of the 1 st adhesive layer (X1) to a hard support and placing a sealing object on a part of the adhesive surface of the 2 nd adhesive layer (X2); step (2): a step in which the bonding surface between the object to be sealed and the 2 nd adhesive layer (X2) is covered with a sealing material, and the sealing material is cured to obtain a cured sealing body; step (3): and a step of expanding the expandable particles to separate the expandable particles at an interface P between the hard support and the 1 st pressure-sensitive adhesive layer (X1).

Description

Method for manufacturing cured sealing body

Technical Field

The present invention relates to a method for producing a cured sealing body.

Background

The adhesive sheet is used not only for semipermanently fixing a member but also for temporarily fixing a target member when processing or inspecting a building material, an interior material, an electronic component, or the like.

Such pressure-sensitive adhesive sheets for temporary fixation are required to have both adhesiveness during use and peelability after use.

For example, patent document 1 discloses a heat-peelable pressure-sensitive adhesive sheet for temporary fixation of cut electronic components, which is provided with a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres on at least one surface of a substrate.

In the heat-peelable pressure-sensitive adhesive sheet, the maximum particle diameter of the heat-expandable microspheres is adjusted with respect to the thickness of the heat-expandable pressure-sensitive adhesive layer, and the center line average roughness of the surface of the heat-expandable pressure-sensitive adhesive layer before heating is adjusted to 0.4 μm or less.

Patent document 1 describes the following: the heat-peelable pressure-sensitive adhesive sheet can exhibit adhesiveness that can prevent poor adhesion such as chip scattering because a sufficient adhesion area to an adherend can be secured when an electronic component is cut, and can be easily peeled off by reducing the contact area with the adherend if the heat-expandable microspheres are expanded by heating after use.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3594853

Disclosure of Invention

Problems to be solved by the invention

In recent years, electronic devices have been reduced in size, thickness, and density, and semiconductor devices mounted in electronic devices are also required to be reduced in size, thickness, and density. As a semiconductor packaging technology capable of meeting such a demand, FOWLP (Fan out Wafer Level Package) is attracting attention.

The FOWLP is a semiconductor package in which a rewiring layer is provided on a surface of a cured sealing body on a semiconductor chip side, and a solder ball and the semiconductor chip are electrically connected to each other through the rewiring layer, wherein the cured sealing body is formed by sealing a plurality of semiconductor chips arranged at a predetermined interval with a sealing material.

FOWLP can extend terminals as solder balls to the outside of a semiconductor chip (Fan-out), and therefore, it can be applied to applications in which the number of terminals is larger than the area of a semiconductor chip.

However, in general, FOWLP is manufactured through the following processes:

a sealing step of placing the circuit surface of a semiconductor chip on an adhesive sheet, filling the periphery of the semiconductor chip with a sealing resin having fluidity heated to about 100 ℃, and heating the resin to form a layer of the sealing resin, or laminating a sealing resin film on the semiconductor chip and heating the resin to laminate the resin; and

and a step of removing the adhesive sheet and forming a rewiring layer and solder balls on the exposed surface of the semiconductor chip side.

In the sealing step of the above-described FOWLP production method, it is also conceivable to use a heat-peelable pressure-sensitive adhesive sheet in which a heat-expandable pressure-sensitive adhesive layer containing heat-expandable microspheres is provided on a substrate, as described in patent document 1, for example.

However, since the heat-expandable pressure-sensitive adhesive layer of the heat-peelable pressure-sensitive adhesive sheet described in patent document 1 contains the heat-expandable microspheres, there is a concern that the adhesive strength is reduced when processing such as a sealing step or inspection is performed, as compared with a pressure-sensitive adhesive layer containing no heat-expandable microspheres.

For example, the decrease in adhesive strength in the sealing step causes defects such as misalignment of the semiconductor chip mounted on the adhesive layer, and adhesion of resin to the circuit surface of the semiconductor chip due to the intrusion of sealing resin into the bonding interface between the semiconductor chip and the adhesive sheet.

In particular, the elastic modulus of the thermally-expansible pressure-sensitive adhesive layer is usually or is adjusted to be low in order to easily form irregularities on the surface when the thermally-expansible microballs are expanded, but there is a concern that the semiconductor chip mounted on the surface of the thermally-expansible pressure-sensitive adhesive layer having a low elastic modulus is likely to be displaced in the sealing step.

The occurrence of misalignment of the semiconductor chip and the adhesion of the sealing resin to the circuit surface of the semiconductor chip cause a reduction in yield in the manufacture of the semiconductor device. Such a problem can occur in an object to be sealed other than the semiconductor chip.

Accordingly, there is a need for a method of manufacturing a cured sealing body that can suppress the following disadvantages that can occur when obtaining a cured sealing body, including: the occurrence of misalignment of an object to be sealed such as a semiconductor chip, and the adhesion of a sealing resin to an exposed surface of the object to be sealed such as a circuit surface of the semiconductor chip.

In the production of FOWLP, a support and a semiconductor chip are generally fixed to each other by a double-sided adhesive sheet having adhesive layers on both sides of a substrate. For example, in the heat-peelable pressure-sensitive adhesive sheet described in patent document 1, a double-sided pressure-sensitive adhesive sheet is generally produced in which a heat-expandable pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer are provided on both sides of a substrate, a semiconductor chip is placed on the heat-expandable pressure-sensitive adhesive layer side, and the pressure-sensitive adhesive layer side is bonded to a support to perform various processes such as a sealing step.

However, in the case of using the heat-peelable pressure-sensitive adhesive sheet, the interface between the heat-expandable pressure-sensitive adhesive layer and the cured sealing material is separated, and the double-sided pressure-sensitive adhesive sheet described above is stuck to the support. In such a case, a cleaning step of the support is required, which causes a reduction in productivity.

On the other hand, a method of attaching the thermally expandable adhesive layer to the support when using the above-described double-sided adhesive sheet is also considered, and it is considered that the peelability when removing the double-sided adhesive sheet from the support after the sealing step is improved.

However, the thermally expandable adhesive layer in which the thermally expandable microspheres have expanded becomes very brittle.

Therefore, in the cured sealant with the double-sided adhesive sheet peeled from the support, since the thermally expandable adhesive layer is located at the outermost layer, a part of the thermally expandable adhesive layer is peeled off during transportation and processing in the subsequent step, and the thermally expandable adhesive layer is easily peeled off. In the case where the thermal expansion adhesive layer after detachment adheres to various devices in the manufacturing environment and contaminates the devices, cleaning of the devices is necessary, and this causes a reduction in productivity.

That is, in the production of the cured sealing body, it is also required to suppress contamination in the production environment without requiring a cleaning process, thereby improving productivity.

The present invention aims to provide a method for producing a cured sealing body, which can effectively suppress the occurrence of misalignment of a sealing object and the adhesion of a sealing resin to the exposed surface of the sealing object when a sealing material is used for the sealing object to obtain the cured sealing body, thereby improving the yield, and can suppress the pollution in the production environment to improve the productivity.

Means for solving the problems

The present inventors have found that the above-mentioned problems can be solved by using an adhesive sheet having a1 st adhesive layer and a 2 nd adhesive layer on both surfaces of a substrate, respectively, in a process of producing a cured sealing body by using a sealing material for a sealing object, the substrate including at least an expandable base layer and a non-expandable base layer containing expandable particles, and the 1 st adhesive layer and the 2 nd adhesive layer being non-expandable adhesive layers.

That is, the present invention relates to the following [1] to [10 ].

[1] A method for producing a cured sealing body by using an adhesive sheet,

the adhesive sheet comprises a substrate (Y) and, respectively, a1 st adhesive layer (X1) and a 2 nd adhesive layer (X2) on both sides of the substrate (Y), wherein the substrate (Y) comprises at least an expandable base layer (Y1) and a non-expandable base layer (Y2) each containing expandable particles, and the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) are non-expandable adhesive layers,

the adhesive sheet is capable of generating unevenness on the adhesive surface of the 1 st adhesive layer (X1) by the expansion of the expandable particles,

the method for producing the cured sealing body comprises the following steps (1) to (3):

step (1): a step of adhering the adhesive surface of the 1 st adhesive layer (X1) to a hard support and placing a sealing object on a part of the adhesive surface of the 2 nd adhesive layer (X2);

step (2): a step in which the object to be sealed and the bonding surface of the 2 nd adhesive layer (X2) on at least the peripheral portion of the object to be sealed are covered with a sealing material, and the sealing material is cured to obtain a cured sealing body in which the object to be sealed is sealed with the sealing material;

step (3): and a step of expanding the expandable particles and separating the expanded expandable particles from the interface P between the hard support and the 1 st adhesive layer (X1) in a state where the cured sealing body is laminated on the 2 nd adhesive layer (X2).

[2] The method for producing a cured sealing body according to the above [1], wherein,

the adhesive sheet has a1 st adhesive layer (X1) on the expandable base material layer (Y1) side of the base material (Y), and has a 2 nd adhesive layer (X2) on the non-expandable base material layer (Y2) side of the base material (Y).

[3] The method for producing a cured sealing body according to the above [1] or [2], wherein,

the base material (Y) comprises the expandable base material layer (Y1), a non-expandable base material layer (Y2-1) provided on the 1 st pressure-sensitive adhesive layer (X1) side of the expandable base material layer (Y1), and a non-expandable base material layer (Y2-2) provided on the 2 nd pressure-sensitive adhesive layer (X2) side of the expandable base material layer (Y1),

the storage modulus E 'of the non-expandable base material layer (Y2-1) when the expandable particles expand is lower than the storage modulus E' of the non-expandable base material layer (Y2-2) when the expandable particles expand.

[4] The method for producing a cured sealing body according to the above [1] or [2], wherein,

the non-expandable substrate layer (Y2) is present at a position farther from the 1 st adhesive layer (X1) than the expandable substrate layer (Y1), the non-expandable substrate layer (Y2) is not present between the expandable substrate layer (Y1) and the 1 st adhesive layer (X1),

the storage modulus E 'of the non-expandable base material layer (Y2) when the expandable particles expand is larger than the storage modulus E' of the expandable base material layer (Y1) when the expandable particles expand.

[5] The method for producing a cured sealing body according to any one of the above [1] to [4], wherein,

in the step (3), when the expandable particles are expanded, the layers constituting the adhesive sheet are not separated from each other.

[6] The method for producing a cured sealing body according to any one of the above [1] to [5], wherein,

the expandable particles are thermally expandable particles having an expansion initiation temperature (t) of 60 to 270 ℃.

[7] The method for producing a cured sealing body according to item [6], wherein,

the expansion of the thermally expandable particles is performed by heat treatment between "expansion start temperature (t) +10 ℃" and "expansion start temperature (t) +60 ℃" of the thermally expandable particles.

[8] The method for producing a cured sealing body according to the above [6] or [7], wherein,

the expandable base material layer (Y1) is a thermally expandable base material layer (Y1-1) containing the thermally expandable particles, and the storage modulus E' (23) of the thermally expandable base material layer (Y1-1) at 23 ℃ is 1.0X 10⁶Pa or above.

[9] The method for producing a cured sealing body according to any one of the above [1] to [8], wherein,

the volume change rate (%) of the non-expandable base material layer (Y2) is less than 2 vol%.

[10] The method for producing a cured sealing body according to any one of the above [1] to [9], wherein,

the object to be sealed is a semiconductor chip.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the method for producing a cured sealing body of the present invention, it is possible to effectively suppress the occurrence of misalignment of a sealing object and the adhesion of a sealing resin to an exposed surface of the sealing object when the cured sealing body is obtained by using a sealing material for the sealing object, thereby improving the yield, and to suppress contamination in the production environment and improve the productivity.

Drawings

Fig. 1 is a schematic cross-sectional view of an adhesive sheet used in the method for manufacturing a semiconductor chip according to the present invention, illustrating an example of the structure of the adhesive sheet.

Fig. 2 is a schematic cross-sectional view of steps (1) to (3) of the method for manufacturing a semiconductor chip according to the present invention.

Description of the symbols

1a, 1b adhesive sheet

(X1) adhesive layer No. 1

(X2) 2 nd adhesive layer

(Y) base Material

(Y1) expandable base Material layer

(Y2) non-expandable substrate layer

(Y2-1) No. 1 non-expandable substrate layer

(Y2-2) No. 2 non-expandable substrate layer

50 hard support

60 object to be sealed

61 exposed surface

70 sealing Material

80 cured seal

Detailed Description

In the present specification, whether a target layer is an "expandable layer" or a "non-expandable layer" can be determined as follows: after the treatment for swelling was performed for 3 minutes, the determination was made based on the volume change rate before and after the treatment, which was calculated from the following equation.

Volume change rate (%) { (volume of the layer after treatment-volume of the layer before treatment)/volume of the layer before treatment } × 100

That is, if the volume change rate is 5 vol% or more, the layer is determined to be an "expandable layer", and if the volume change rate is less than 5 vol%, the layer is determined to be a "non-expandable layer".

As the "treatment for expanding" in the present invention, for example, in the case where the expandable particles are thermally expandable particles, the heat treatment may be performed for 3 minutes at the expansion start temperature (t) of the thermally expandable particles.

In the present specification, the "active ingredient" refers to a component other than the diluting solvent among the components contained in the target composition.

The weight average molecular weight (Mw) is a value in terms of standard polystyrene measured by a Gel Permeation Chromatography (GPC) method, and specifically is a value measured by the method described in examples.

In the present specification, for example, "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid", and other similar terms are also used.

In addition, regarding a preferable numerical range (for example, a range of a content or the like), the lower limit value and the upper limit value described in the paragraph may be independently combined. For example, according to the description of "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit value (10)" and the "more preferable upper limit value (60)" may be combined to obtain "10 to 60".

[ method for producing cured sealing body of the present invention ]

The method for producing a cured product of the present invention (hereinafter also simply referred to as "the method for producing the present invention") is a method for producing a cured product of the present invention using a pressure-sensitive adhesive sheet having a substrate (Y) and having a1 st pressure-sensitive adhesive layer (X1) and a 2 nd pressure-sensitive adhesive layer (X2) on both surfaces of the substrate (Y), the substrate (Y) having at least an expandable base layer (Y1) and a non-expandable base layer (Y2) containing expandable particles, the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) being non-expandable pressure-sensitive adhesive layers, the pressure-sensitive adhesive sheet being capable of generating irregularities on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) by expansion of the expandable particles,

the production method of the present invention includes the following steps (1) to (3).

Step (1): and a step of adhering the adhesive surface of the 1 st adhesive layer (X1) to the hard support and placing the object to be sealed on a part of the adhesive surface of the 2 nd adhesive layer (X2).

Step (2): and a step of coating the object to be sealed and the bonding surface of the 2 nd pressure-sensitive adhesive layer (X2) on at least the peripheral portion of the object to be sealed with a sealing material, and curing the sealing material to obtain a cured sealing body in which the object to be sealed is sealed with the sealing material.

[ constitution of adhesive sheet used in production method of the present invention ]

Fig. 1 is a schematic cross-sectional view of the adhesive sheet showing an example of the structure of the adhesive sheet used in the production method of the present invention.

The pressure-sensitive adhesive sheet used in the production method of the present invention may be exemplified by a pressure-sensitive adhesive sheet 1a having a substrate (Y) as shown in fig. 1(a), the substrate (Y) including at least an expandable base layer (Y1) and a non-expandable base layer (Y2), and having a1 st pressure-sensitive adhesive layer (X1) and a 2 nd pressure-sensitive adhesive layer (X2) on both sides of the substrate (Y), the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) being non-expandable pressure-sensitive adhesive layers.

The substrate (Y) of the psa sheet 1a shown in fig. 1(a) has a structure in which an expandable substrate layer (Y1) and a non-expandable substrate layer (Y2) are directly laminated, but the substrate (Y) may have other structures.

For example, like the substrate (Y) of the adhesive sheet 1b shown in FIG. 1(b), the 1 st non-heat-expandable substrate layer (Y2-1) and the 2 nd non-heat-expandable substrate layer (Y2-2) may be provided on both sides of the expandable substrate layer (Y1).

In the pressure-sensitive adhesive sheet used in one embodiment of the present invention, a release material may be further laminated on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) and the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2).

In this configuration, a material in which a release material having both surfaces subjected to a release treatment is laminated on the adhesive surface of one of the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) may be wound into a roll.

These release materials are provided for protecting the adhesive surface of the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2), and are removed when the adhesive sheet is used.

In the psa sheet 1a shown in fig. 1(a), for example, when the peeling force when peeling the release material laminated on the 1 st psa layer (X1) is equal to the peeling force when peeling the release material laminated on the 2 nd psa layer (X2), the peeling materials on both sides are pulled outward and peeled off, which may cause the psa sheet 1a to be torn off and peeled off with the two release materials.

Therefore, as the release material laminated on the 1 st pressure-sensitive adhesive layer (X1) and the release material laminated on the 2 nd pressure-sensitive adhesive layer (X2), two release materials designed to have different release forces from the pressure-sensitive adhesive layers to be stuck to each other are preferably used.

The pressure-sensitive adhesive sheet used in the production method of the present invention is adjusted so that the swelling of the expandable particles can produce irregularities on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1).

For example, the psa sheet 1a shown in fig. 1(a) has a structure in which a1 st psa layer (X1) as a non-expandable psa layer is laminated on an expandable substrate layer (Y1) containing expandable particles, and a 2 nd psa layer (X2) as a non-expandable psa layer is laminated on a non-expandable substrate layer (Y2).

In the psa sheet 1a, when the expandable particles in the expandable base material layer (Y1) expand, irregularities are formed on the surface of the expandable base material layer (Y1), and the 1 st psa layer (X1) in contact with this surface is lifted up by these irregularities, resulting in irregularities also being formed on the adhesive surface of the 1 st psa layer (X1).

In the production method of the present invention, as in the above step (1), the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) is bonded to the hard support.

Further, in the step (3), when the expandable particles are expanded, since the surface of the 1 st pressure-sensitive adhesive layer (X1) to be bonded is uneven and the contact area with the hard support is reduced, the expandable particles can be easily separated at a time by a small force at the interface P between the hard support and the 1 st pressure-sensitive adhesive layer (X1).

In addition, when the expandable particles are expanded, the expandable substrate layer (Y1) and the non-expandable substrate layer (Y2) may be adjusted so that the separation can be easily achieved at a time with a small force even at the interface.

On the other hand, as in the above step (1), the object to be sealed is placed on the adhesion surface of the 2 nd pressure-sensitive adhesive layer (X2), and in the step (2), the object to be sealed placed and the 2 nd pressure-sensitive adhesive layer (X2) in the peripheral portion of the object to be sealed are covered with the sealing material, and the sealing material is cured to form a cured sealed body. Then, when the expandable particles are expanded as defined in the above step (3), the cured sealing body is laminated on the 2 nd pressure-sensitive adhesive layer (X2) and separated at the interface P between the hard support and the 1 st pressure-sensitive adhesive layer (X1).

That is, when separating from the hard support, it is necessary to hold a plurality of semiconductor chips on the 2 nd adhesive layer (X2) of the adhesive sheet.

For this reason, the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) is preferably adjusted so as to suppress the formation of irregularities, so that it can maintain a level of adhesive force capable of holding the cured sealing body even under the expansion of the expandable particles.

For example, in the psa sheet 1a shown in fig. 1(a), the non-expandable base layer (Y2) is provided on the surface of the expandable base layer (Y1) opposite to the 1 st psa layer (X1), and the 2 nd psa layer (X2) is laminated on the surface of the non-expandable base layer (Y2).

In the psa sheet 1a, when the expandable particles expand, the non-expandable base material layer (Y2) is present, and therefore stress from the expandable base material layer (Y1) side due to expansion of the expandable particles is absorbed by the non-expandable base material layer (Y2). As a result, the formation of irregularities on the bonding surface of the 2 nd pressure-sensitive adhesive layer (X2) laminated on the non-expandable base material layer (Y2) is suppressed, and the cured sealant can be held in a state laminated on the bonding surface.

In the psa sheet 1b shown in fig. 1(b), the storage modulus E' of the 1 st non-expandable substrate layer (Y2-1) is preferably adjusted to be low so that irregularities are formed on the adhesive surface of the 1 st psa layer (X1) when the expandable particles expand.

On the other hand, the storage modulus E' of the 2 nd non-thermally-expansible base material layer (Y2-2) is preferably adjusted to be high so as to suppress the formation of irregularities on the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) when the expandable particles expand.

That is, the storage modulus E 'of the 1 st non-expandable substrate layer (Y2-1) when the expandable particles expand is preferably adjusted to be lower than the storage modulus E' of the 2 nd non-expandable substrate layer (Y2-2) when the expandable particles expand.

However, when it is desired to obtain a cured sealed body by using an expandable pressure-sensitive adhesive layer containing expandable particles and placing a sealing object on the adhesive surface of the expandable pressure-sensitive adhesive layer as described in patent document 1, the adhesive force tends to be insufficient because the expandable pressure-sensitive adhesive layer on which the sealing object is placed contains the expandable particles.

Therefore, in the sealing step in the step (2), there is a possibility that displacement of the object to be sealed occurs, and the sealing resin of the sealing material enters the adhesion interface between the object to be sealed and the expandable adhesive layer, and the sealing resin adheres to the exposed surface of the object to be sealed (for example, the circuit surface of the semiconductor chip).

In addition, the following methods are also considered: a cured sealed body is obtained by using a double-sided pressure-sensitive adhesive sheet having an expandable pressure-sensitive adhesive layer on one surface of a substrate and a non-expandable pressure-sensitive adhesive layer on the other surface, bonding the expandable pressure-sensitive adhesive layer to a hard support, and placing a sealing object on the non-expandable pressure-sensitive adhesive layer.

However, since the adhesive force of the expandable adhesive layer tends to be insufficient and the object to be sealed and the rigid support are not sufficiently fixed, the object to be sealed placed on the non-expandable adhesive layer tends to move when the object to be sealed is coated with the sealing material. Therefore, in the sealing step, the position of the object to be sealed is likely to be displaced, and the adhesion of the sealing resin to the exposed surface of the object to be sealed is likely to occur.

It is also conceivable to avoid the above-described drawbacks by selecting an adhesive resin so that the expandable adhesive layer has high adhesive force.

However, when the expandable pressure-sensitive adhesive layer is made to have high adhesive force, expansion of the expandable particles may be insufficient depending on the type of the pressure-sensitive adhesive resin contained in the expandable pressure-sensitive adhesive layer, and even if the expandable particles are expanded, the expandable particles may not be easily peeled off at one time.

That is, when a sealing object is placed on the expandable pressure-sensitive adhesive layer having a high adhesive force, there is a possibility that it is difficult to peel the formed cured seal from the expandable pressure-sensitive adhesive layer, and even if the cured seal is peeled, a part of the expandable pressure-sensitive adhesive layer may remain in the cured seal.

In addition, when an expandable pressure-sensitive adhesive layer having high adhesive force is attached to a hard support, when the expandable particles are expanded to peel the double-sided pressure-sensitive adhesive sheet from the hard support, a part of the pressure-sensitive adhesive layer may remain on the surface of the hard support, and a cleaning step of the support may be required, which also causes a reduction in productivity.

In addition, the expandable adhesive layer after expansion of the expandable particles becomes very brittle. In the cured seal body with a double-sided adhesive sheet separated from the hard support, the expandable adhesive layer is located on the outermost layer, and when the cured seal body is conveyed or processed in the next step, a part of the expandable adhesive layer located on the outermost layer is detached, and the expandable adhesive layer is likely to be peeled off.

When the exfoliated expandable adhesive layer adheres to various devices in the production environment and contaminates the devices, the device needs to be cleaned, which causes a reduction in productivity.

On the other hand, the adhesive sheet used in the production method of the present invention has a substrate (Y) that includes at least a swellable base material layer (Y1) containing swellable particles and a non-swellable base material layer (Y2), and is adjusted so that irregularities are formed on the adhesive surface of the 1 st adhesive layer (X1) when the swellable particles swell.

Therefore, the adhesive composition as a material for forming the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) is also highly flexible in selection.

That is, unlike the expandable pressure-sensitive adhesive layer limited by the pressure-sensitive adhesive resin used as described above, the pressure-sensitive adhesive resin used for the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) can be selected without considering the expandability of the expandable particles.

Further, since the 1 st pressure-sensitive adhesive layer (X1) to be bonded to the hard support is a non-expandable pressure-sensitive adhesive layer and does not need to contain expandable particles, it can be sufficiently fixed to the hard support, and therefore, it is possible to effectively suppress the disadvantages of displacement of the object to be sealed and adhesion of the sealing resin to the exposed surface of the object to be sealed, which are caused by insufficient fixation of the object to be sealed to the hard support.

In addition, when the hard support and the bonded adhesive sheet are separated, the hard support and the bonded adhesive sheet can be easily separated at one time, and the contamination of the separated hard support can be effectively suppressed.

In the cured sealant with the psa sheet after separation, the expandable substrate layer (Y1) containing the expanded expandable particles is not located at least at the outermost layer, and has a certain degree of strength compared to the case where the adhesive layer contains the expandable particles. Therefore, the expandable base material layer (Y1) after expansion is less likely to fall off.

In the cured sealant with the psa sheet after separation, the 1 st psa layer (X1) located at the outermost layer is a non-expandable psa layer and does not need to contain expandable particles, so that disadvantages such as the detachment of the 1 st psa layer (X1) are not likely to occur.

Therefore, in the production method of the present invention, contamination in the production environment can be effectively suppressed, and therefore, a cleaning step accompanied by contamination is not required, and excellent productivity can be exhibited.

[ Properties of adhesive sheet ]

The adhesive sheet used in one embodiment of the present invention is easily separated at one time with a small force at the interface P between the hard support and the 1 st adhesive layer (X1) by generating unevenness on the adhesive surface of the 1 st adhesive layer (X1) adhered to the hard support due to expansion of the expandable particles.

Here, in the pressure-sensitive adhesive sheet used in one embodiment of the present invention, the peeling force (F) at the time of separating at the interface P by swelling the swellable particles is set to₁) It is usually 0 to 2000mN/25mm, preferably 0 to 1000mN/25mm, more preferably 0 to 150mN/25mm, still more preferably 0 to 100mN/25mm, and still more preferably 0 to 50mN/25 mm.

The peel force (F) is₁) In the case of 0mN/25mm, the peel force may be too small to be measured even when the peel force is measured by the method described in examples.

On the other hand, when the sealing object is cured with the sealing material before the expandable particles expand, the higher the adhesive strength of the 1 st pressure-sensitive adhesive layer (X1), the more preferable the adhesive strength is from the viewpoint of effectively suppressing the occurrence of misalignment of the sealing object and the adhesion of the sealing resin to the exposed surface of the sealing object, and improving the yield.

From the above-described viewpoint, in the pressure-sensitive adhesive sheet used in one embodiment of the present invention, the peeling force (F) when the expandable particles are separated at the interface P before expansion₀) Preferably 0.05 to 10.0N/25mm, more preferably 0.1 to 8.0N/25mm, still more preferably 0.15 to 6.0N/25mm, and still more preferably 0.2 to 4.0N/25 mm.

The above-mentioned peeling force (F)₀) The adhesion of the 1 st adhesive layer (X1) to the rigid support can also be considered.

In the adhesive sheet used in one embodiment of the present invention, the peeling force (F)₁) And peel force (F)₀) Ratio of [ (F)₁)/(F₀)]Preferably 0 to 0.9, more preferably 0 to 0.8, further preferably 0 to 0.5, and further preferably 0 to 0.2.

The peel force (F)₁) Is a value measured in an environment where the expandable particles expand. For example, when the expandable particles are thermally expandable particles, the peel force (F) is measured₁) The temperature condition in the case (a) is not less than the expansion starting temperature (t) of the thermally expandable particles.

On the other hand, as a measure of the peeling force (F)₀) The temperature condition in the case of the above is not limited as long as the expandable particles are not expanded, and is substantially room temperature (23 ℃).

Wherein the peel force (F)₁) And peel force (F)₀) The more specific measurement conditions and measurement methods in (4) are based on the methods described in examples.

In addition, in the adhesive sheet used in one embodiment of the present invention, the adhesive strength of the 2 nd adhesive layer (X2) at room temperature (23 ℃) is preferably 0.1 to 10.0N/25mm, more preferably 0.2 to 8.0N/25mm, further preferably 0.4 to 6.0N/25mm, and further preferably 0.5 to 4.0N/25 mm.

In the present specification, the adhesive force of the 2 nd adhesive layer (X2) is a value measured by the method described in examples.

Hereinafter, each layer constituting the pressure-sensitive adhesive sheet used in one embodiment of the present invention will be described.

< substrate (Y) >)

The base material (Y) of the pressure-sensitive adhesive sheet used in one embodiment of the present invention includes at least a swellable base material layer (Y1) containing swellable particles and a non-swellable base material layer (Y2).

The substrate (Y) may be a laminate of an expandable substrate layer (Y1) and a non-expandable substrate layer (Y2) as in the psa sheet 1a shown in fig. 1(a), or a laminate of a1 st non-thermally expandable substrate layer (Y2-1) and a 2 nd non-thermally expandable substrate layer (Y2-2) provided on both sides of an expandable substrate layer (Y1) as in the psa sheet 1b shown in fig. 1 (b).

The substrate (Y) of the psa sheet used in one embodiment of the invention may have a configuration in which an adhesive layer is provided between the expandable substrate layer (Y1) and the non-expandable substrate layer (Y2).

For example, in the case of the configuration of the adhesive sheet 1b shown in fig. 1(b), an adhesive layer may be provided between the expandable base material layer (Y1) and the 1 st non-thermally-expandable base material layer (Y2-1) and/or the 2 nd non-thermally-expandable base material layer (Y2-2).

By providing the adhesive layer, the interlayer adhesion between the expandable base material layer (Y1) and the non-expandable base material layer (Y2) can be improved.

The adhesive layer may be formed of a conventional adhesive, an adhesive composition as a forming material of the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2).

In one embodiment of the present invention, from the viewpoint of obtaining a pressure-sensitive adhesive sheet in which unevenness is generated on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) by swelling of the swellable particles, and the formation of unevenness is suppressed on the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2), the substrate (Y) is preferably a material having a swellable base layer (Y1) and a non-swellable base layer (Y2) at least on the outermost surface.

This embodiment includes a substrate (Y) obtained by laminating the substrate (Y), the expandable base material layer (Y1), the adhesive layer, and the non-expandable base material layer (Y2) of the adhesive sheet 1a shown in fig. 1(a) in this order.

The expandable base material layer (Y1) and the non-expandable base material layer (Y2) constituting the base material (Y) are both non-adhesive layers.

In the present invention, when determining whether or not a layer is a non-adhesive layer, if the probe tack value measured in accordance with JIS Z0237:1991 with respect to the surface of the layer to be determined is less than 50mN/5mm φ, the layer is determined to be a "non-adhesive layer".

The probe tack values of the surfaces of the expandable substrate layer (Y1) and the non-expandable substrate layer (Y2) of the pressure-sensitive adhesive sheet (I) used in one embodiment of the present invention are each independently usually lower than 50mN/5mm, preferably lower than 30mN/5mm, more preferably lower than 10mN/5mm, and still more preferably lower than 5mN/5 mm.

In the present specification, the specific method for measuring the probe viscosity value on the surface of the heat-expandable substrate can be the method described in the examples.

In the pressure-sensitive adhesive sheet used in one embodiment of the present invention, the thickness of the base material (Y) is preferably 15 to 2000 μm, more preferably 25 to 1500 μm, still more preferably 30 to 1000 μm, and still more preferably 40 to 500 μm.

The thickness of the expandable base material (Y1) before expansion of the expandable particles is preferably 10 to 1000 μm, more preferably 20 to 700 μm, still more preferably 25 to 500 μm, and still more preferably 30 to 300. mu.m.

The thickness of the non-swelling substrate (Y2) is preferably 10 to 1000 μm, more preferably 20 to 700 μm, still more preferably 25 to 500 μm, and still more preferably 30 to 300 μm.

In the present specification, when a plurality of expandable substrates (Y1) or non-expandable substrates (Y2) are present with another layer interposed therebetween as in the psa sheet 1b shown in fig. 1(b), the thickness of the expandable substrate (Y1) or non-expandable substrate (Y2) indicates the thickness of each layer.

In the pressure-sensitive adhesive sheet used in one embodiment of the present invention, the thickness ratio [ (Y1)/(Y2) ] of the expandable base material layer (Y1) to the non-expandable base material layer (Y2) before expansion of the expandable particles is preferably 0.02 to 200, more preferably 0.03 to 150, and further preferably 0.05 to 100.

In the psa sheet used in one embodiment of the present invention, the thickness ratio [ (Y1)/(X1) ] between the swellable substrate layer (Y1) before swelling of the swellable particles and the 1 st psa layer (X1) directly laminated on the swellable substrate layer (Y1) is preferably 0.2 or more, more preferably 0.5 or more, even more preferably 1.0 or more, even more preferably 5.0 or more, and preferably 1000 or less, more preferably 200 or less, even more preferably 60 or less, even more preferably 30 or less.

In the psa sheet used in one embodiment of the present invention, the thickness ratio [ (Y2)/(X2) ] between the non-expandable substrate layer (Y2) and the 2 nd psa layer (X2) directly laminated on the non-expandable substrate layer (Y2) is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more, and is preferably 20 or less, more preferably 10 or less, and still more preferably 5 or less.

The expandable base material layer (Y1) and the non-expandable base material layer (Y2) constituting the base material (Y) will be described below.

< expandable substrate layer (Y1) >)

The expandable base material layer (Y1) constituting the base material (Y) is a layer containing expandable particles and expandable by a predetermined expansion treatment.

The content of the expandable particles in the expandable base material layer (Y1) is preferably 1 to 40 mass%, more preferably 5 to 35 mass%, even more preferably 10 to 30 mass%, and even more preferably 15 to 25 mass% with respect to the total mass (100 mass%) of the expandable base material layer (Y1).

In addition, from the viewpoint of improving interlayer adhesion between the expandable base material layer (Y1) and another layer laminated thereon, the surface of the expandable base material layer (Y1) may be subjected to a surface treatment by an oxidation method, a roughening method, or the like, an easy adhesion treatment, or an undercoating treatment.

Examples of the oxidation method include: examples of the method of forming the concavities and convexities include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet type), hot air treatment, ozone treatment, and ultraviolet irradiation treatment: sand blasting, solvent treatment, and the like.

As the expandable particles contained in the expandable base layer (Y1), any particles that expand by being subjected to a predetermined treatment may be used, and examples thereof include: thermally expandable particles that expand when heated to a predetermined temperature or higher, UV expandable particles that expand when gas is generated inside the particles by absorbing a predetermined amount of ultraviolet light, and the like.

The volume maximum expansion ratio of the expandable particles is preferably 1.5 to 100 times, more preferably 2 to 80 times, further preferably 2.5 to 60 times, and further preferably 3 to 40 times.

The average particle diameter of the expandable particles before expansion at 23 ℃ is preferably 3 to 100 μm, more preferably 4 to 70 μm, further preferably 6 to 60 μm, and further preferably 10 to 50 μm.

The average particle diameter of the expandable particles is the volume median diameter (D)₅₀) The term "particle size" means a particle size at which the cumulative volume frequency calculated from the particles having a small particle size among the expandable particles corresponds to 50% in the particle distribution of the expandable particles measured by a laser diffraction particle size distribution measuring apparatus (for example, product name "Mastersizer 3000" manufactured by Malvern).

The particle diameter (D) of the expandable particles before expansion at 23 ℃ is 90%₉₀) Preferably 10 to 150 μm, more preferably 20 to 100 μm, further preferably 25 to 90 μm, and further preferably 30 to 80 μm.

The expandable particles have a 90% particle diameter (D)₉₀) The cumulative volume frequency calculated from particles having a small particle diameter among the expandable particles in the particle distribution of the expandable particles measured by a laser diffraction particle size distribution measuring apparatus (for example, product name "Mastersizer 3000" manufactured by Malvern) corresponds to a particle diameter of 90%.

In one embodiment of the present invention, the expandable particles are preferably those having an expansion initiation temperature (t) of 60 to 270 ℃.

That is, the expandable base material layer (Y1) is preferably a thermally expandable base material layer (Y1-1) containing thermally expandable particles having an expansion start temperature (t) of 60 to 270 ℃, and more preferably the thermally expandable base material layer (Y1-1) satisfies the following condition (1).

Condition (1): the storage modulus E' (t) of the thermally-expansible base layer (Y1-1) is 1.0X 10 at the expansion initiation temperature (t) of the thermally-expansible particles⁷Pa or less.

In the present specification, the storage modulus E' of the thermally expandable base material layer (Y1-1) at a given temperature is a value measured by the method described in examples.

The condition (1) is considered to be an index for characterizing the rigidity of the thermally-expansible base layer (Y1-1) immediately before the thermally-expansible particles expand.

That is, if the thermally expandable base material layer (Y1-1) has flexibility of such a degree as to satisfy the above condition (1) when the thermally expandable particles expand, irregularities are likely to be formed on the surface of the thermally expandable base material layer (Y1-1), and irregularities are also likely to be formed on the adhesive surface of the 1 st pressure-sensitive adhesive layer (X1). As a result, the hard support and the 1 st adhesive layer (X1) can be easily separated at a time by a small force at the interface P.

From the above viewpoint, the storage modulus E' (t) of the thermally expandable base material layer (Y1-1) defined by the condition (1) is preferably 9.0 × 10⁶Pa or less, more preferably 8.0X 10⁶Pa or less, more preferably 6.0X 10⁶Pa or less, more preferably 4.0X 10⁶Pa or less.

In addition, the storage modulus E' (t) of the thermally-expansible base layer (Y1-1) defined by the condition (1) is preferably 1.0 × 10 from the viewpoints of suppressing the flow of the thermally-expansible particles after expansion, improving the shape retention of irregularities generated on the surface of the thermally-expansible base layer (Y1-1), and easily generating irregularities on the adhesive surface of the 1 st pressure-sensitive adhesive layer (X1)³Pa or more, more preferably 1.0X 10⁴Pa or more, preferably 1.0X 10⁵Pa or above.

The thermally expandable base material layer (Y1-1) preferably satisfies the following condition (2), and more preferably satisfies the condition (2) in addition to the condition (1).

Condition (2): the heat-expandable base material layer (Y1-1) had a storage modulus E' (23) of 1.0X 10 at 23 DEG C⁶Pa or above.

By obtaining the thermally expandable base material layer (Y1-1) satisfying the above condition (2), it is possible to prevent displacement when the semiconductor wafer is bonded to the bonding surface of the 2 nd adhesive layer (X2), and also possible to prevent excessive sinking of the semiconductor wafer into the 2 nd adhesive layer (X2).

From the above viewpoint, the storage modulus E' (23) of the thermally expandable base material layer (Y1-1) defined under the above condition (2) is preferably 5.0 × 10⁶～5.0×10¹²Pa, more preferably 1.0X 10⁷～1.0×10¹²Pa, more preferably 5.0X 10⁷～1.0×10¹¹Pa, more preferably 1.0X 10⁸～1.0×10¹⁰Pa。

The thermally expandable particles contained in the thermally expandable base material layer (Y1-1) are preferably thermally expandable particles having an expansion initiation temperature (t) of 60 to 270 ℃.

In the present specification, the expansion start temperature (t) of the thermally expandable particles is a value measured by the following method.

[ method for measuring expansion initiation temperature (t) of thermally expandable particles ]

A sample was prepared by placing 0.5mg of the thermally expandable particles to be measured in an aluminum cup having a diameter of 6.0mm (inner diameter: 5.65mm) and a depth of 4.8mm, and covering the aluminum cup with an aluminum lid (diameter: 5.6mm and thickness: 0.1mm) from above.

The height of the sample was measured using a dynamic viscoelasticity measuring apparatus in a state where a force of 0.01N was applied to the sample from the upper part of the aluminum cap by a indenter. Then, the sample was heated from 20 ℃ to 300 ℃ at a temperature rising rate of 10 ℃/min while a force of 0.01N was applied by the indenter, and the amount of displacement of the indenter in the vertical direction was measured, and the displacement start temperature in the positive direction was defined as the expansion start temperature (t).

The thermally expandable particles are preferably a microencapsulated blowing agent containing an outer shell made of a thermoplastic resin and an encapsulated component encapsulated by the outer shell and vaporized when heated to a predetermined temperature.

Examples of the thermoplastic resin constituting the shell of the microencapsulated blowing agent include: vinylidene chloride-acrylonitrile copolymers, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, and the like.

Examples of the inner package component enclosed by the outer shell include: propane, butane, pentane, hexane, heptane, octane, nonane, decane, isobutane, isopentane, isohexane, isoheptane, isooctane, isononane, isodecane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isododecane, cyclotridecane, hexylcyclohexane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, isotridecyl, 4-methyldodecane, isotetradecane, isopentadecane, isohexadecane, 2,4,4,6,8, 8-heptamethylnonane, isoheptadecane, isooctadecane, isononane, 2,6,10, 14-tetramethylpentadecane, cyclotridecane, heptylcyclohexane, n-octylcyclohexane, cyclopentadecane, nonylcyclohexane, decylcyclohexane, pentadecylcyclohexane, hexadecylcyclohexane, isohexadecane, isopentadecane, isopentane, hexadecane, heptadecane, Heptadecylcyclohexane, octadecylcyclohexane, and the like.

These inner-containing components may be used alone or in combination of two or more.

The expansion starting temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of the encapsulated component.

The expandable substrate layer (Y1) is preferably formed from a resin composition (Y) containing a resin and expandable particles.

The resin composition (y) may contain a base material additive as needed within a range not to impair the effects of the present invention.

Examples of the additive for a base material include: ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, colorants, and the like.

These additives for base materials may be used alone or in combination of two or more.

When these additives for base materials are contained, the content of each additive for base materials is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, per 100 parts by mass of the resin.

As described above, the expandable particles contained in the resin composition (Y) which is a material for forming the expandable base layer (Y1) are preferably thermally expandable particles.

The content of the expandable particles is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, still more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass, based on the total amount (100% by mass) of the active ingredients in the resin composition (y).

The resin contained in the resin composition (Y) as a material for forming the expandable base layer (Y1) may be a non-adhesive resin or an adhesive resin.

That is, even if the resin contained in the resin composition (Y) is an adhesive resin, the adhesive resin and the polymerizable compound may be subjected to a polymerization reaction in the process of forming the expandable base layer (Y1) from the resin composition (Y), and the resulting resin may be a non-adhesive resin, and the expandable base layer (Y1) containing the resin may be non-adhesive.

The weight average molecular weight (Mw) of the resin contained in the resin composition (y) is preferably 1000 to 100 ten thousand, more preferably 1000 to 70 ten thousand, and still more preferably 1000 to 50 ten thousand.

When the resin is a copolymer having two or more kinds of structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

The content of the resin is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, even more preferably 65 to 90% by mass, and even more preferably 70 to 85% by mass, based on the total amount (100% by mass) of the active ingredients in the resin composition (y).

In one embodiment of the present invention, in order to obtain a swellable base layer (Y1) in which unevenness is easily formed on the surface when the swellable particles swell, the resin contained in the resin composition (Y) preferably contains at least one selected from an acrylic urethane resin and an olefin resin.

The acrylic urethane resin is preferably the following resin (U1).

An acrylic urethane resin (U1) obtained by polymerizing a Urethane Prepolymer (UP) and a vinyl compound containing a (meth) acrylate.

[ urethane acrylate resin (U1) ]

As the Urethane Prepolymer (UP) forming the main chain of the acrylic urethane-based resin (U1), a reaction product of a polyol and a polyisocyanate is exemplified.

The Urethane Prepolymer (UP) is preferably a prepolymer obtained by further performing a chain extension reaction using a chain extender.

Examples of the polyol to be a raw material of the Urethane Prepolymer (UP) include: alkylene polyols, ether polyols, ester polyols, esteramide polyols, ester-ether polyols, carbonate polyols, and the like.

These polyols may be used alone or in combination of two or more.

The polyol used in one embodiment of the present invention is preferably a diol, more preferably an ester diol, an alkylene diol, and a carbonate diol, and even more preferably an ester diol or a carbonate diol.

Examples of the ester diol include polycondensates of one or more selected from the following diols and one or more selected from the following dicarboxylic acids and anhydrides thereof: alkane diols such as 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, and 1, 6-hexanediol, and alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; the dicarboxylic acids include: phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4-diphenyldicarboxylic acid, diphenylmethane-4, 4' -dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, chlorendic acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1, 3-dicarboxylic acid, cyclohexane-1, 4-dicarboxylic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid, and the like.

Specific examples thereof include: polyethylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate 1, 6-hexanediol, polyhexamethylene isophthalate 1, 6-hexanediol, polyhexamethylene glycol adipate glycol, polyethylene glycol propylene adipate glycol, polybutylene adipate 1, 6-hexanediol, polydiethylene glycol adipate glycol, poly (polytetramethylene ether) adipate glycol, poly (3-methylpentaneadipate) glycol, polyethylene glycol azelate glycol, polyethylene glycol sebacate glycol, polybutylene azelate glycol, polybutylene sebacate glycol, and polybutylene terephthalate glycol.

Examples of alkylene glycols include: alkane diols such as 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, and 1, 6-hexanediol; alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; polyoxyalkylene glycols such as polytetramethylene glycol; and so on.

Examples of the carbonate diol include: 1, 4-tetramethylene carbonate diol, 1, 5-pentamethylene carbonate diol, 1, 6-hexamethylene carbonate diol, 1, 2-propylene carbonate diol, 1, 3-propylene carbonate diol, 2-dimethylpropylene carbonate diol, 1, 7-heptamethylene carbonate diol, 1, 8-octamethylene carbonate diol, 1, 4-cyclohexane carbonate diol, etc.

Examples of the polyisocyanate to be used as a raw material of the Urethane Prepolymer (UP) include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates.

These polyisocyanates may be used alone or in combination of two or more.

These polyisocyanates may be modified trimethylolpropane adduct type, biuret type modified by reaction with water, or isocyanurate type modified containing an isocyanurate ring.

Among these, the polyisocyanate used in one embodiment of the present invention is preferably a diisocyanate, and more preferably at least one selected from the group consisting of 4, 4' -diphenylmethane diisocyanate (MDI), 2, 4-toluene diisocyanate (2,4-TDI), 2, 6-toluene diisocyanate (2,6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate.

Examples of the alicyclic diisocyanate include: 3-isocyanatomethyl-3, 5, 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate and the like, preferably isophorone diisocyanate (IPDI).

In one embodiment of the present invention, the Urethane Prepolymer (UP) forming the main chain of the acrylic urethane resin (U1) is preferably a linear urethane prepolymer having an ethylenically unsaturated group at both ends, which is a reaction product of a diol and a diisocyanate.

As a method for introducing an ethylenically unsaturated group into both ends of the linear urethane prepolymer, a method in which an NCO group at the end of a linear urethane prepolymer obtained by reacting a diol and a diisocyanate compound is reacted with a hydroxyalkyl (meth) acrylate is exemplified.

Examples of the hydroxyalkyl (meth) acrylate include: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.

The vinyl compound forming the side chain of the acrylic urethane resin (U1) contains at least (meth) acrylate.

The (meth) acrylate is preferably at least one selected from the group consisting of alkyl (meth) acrylates and hydroxyalkyl (meth) acrylates, and more preferably an alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate are used in combination.

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

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

In addition, examples of the hydroxyalkyl (meth) acrylate include the same hydroxyalkyl (meth) acrylate as described above for introducing an ethylenically unsaturated group to both ends of the linear urethane prepolymer.

Examples of the vinyl compound other than the (meth) acrylate include: aromatic hydrocarbon vinyl compounds such as styrene, α -methylstyrene and vinyltoluene; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; polar group-containing monomers such as vinyl acetate, vinyl propionate, (meth) acrylonitrile, N-vinylpyrrolidone, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, and (meth) acrylamide; and so on.

These compounds may be used alone, or two or more of them may be used in combination.

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

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

In the acrylic urethane resin (U1) used in one embodiment of the present invention, the content ratio [ (U11)/(U12) ] of the structural unit (U11) derived from the Urethane Prepolymer (UP) to the structural unit (U12) derived from the vinyl compound is preferably 10/90 to 80/20, more preferably 20/80 to 70/30, still more preferably 30/70 to 60/40, and still more preferably 35/65 to 55/45 in terms of mass ratio.

[ olefin-based resin ]

The olefin-based resin preferably used as the resin contained in the resin composition (y) includes a polymer having at least a structural unit derived from an olefin monomer.

The olefin monomer is preferably an α -olefin having 2 to 8 carbon atoms, and specific examples thereof include: ethylene, propylene, butene, isobutylene, 1-hexene, and the like.

Of these, ethylene and propylene are preferred.

Specific examples of the olefin-based resin include: ultra-low density polyethylene (VLDPE, density: 880 kg/m)³Above and below 910kg/m³) Low density polyethylene (LDPE, density: 910kg/m³Above and below 915kg/m³) Medium density polyethylene (MDPE, density: 915kg/m³Above and below 942kg/m³) High density polyethylene (HDPE, density: 942kg/m³The above), linear low-density polyethylene, and other polyethylene resins; polypropylene resin (PP); polybutene resin (PB); ethylene-propylene copolymers; olefin-based elastomers (TPO); ethylene-vinyl acetate copolymers (EVA); olefin terpolymers such as ethylene-propylene- (5-ethylidene-2-norbornene); and so on.

In one embodiment of the present invention, the olefin-based resin may be a modified olefin-based resin further modified with one or more kinds of modification selected from acid modification, hydroxyl modification, and acrylic modification.

For example, as an acid-modified olefin-based resin obtained by acid-modifying an olefin-based resin, there can be mentioned a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or an acid anhydride thereof onto the above-mentioned unmodified olefin-based resin.

Examples of the unsaturated carboxylic acid or anhydride thereof include: maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth) acrylic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride, and the like.

The unsaturated carboxylic acid or anhydride thereof may be used alone or in combination of two or more.

Examples of the acrylic-modified olefin-based resin obtained by acrylic-modifying an olefin-based resin include modified polymers obtained by graft-polymerizing alkyl (meth) acrylates as side chains onto the above-mentioned unmodified olefin-based resin as a main chain.

The alkyl group of the alkyl (meth) acrylate has preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, and still more preferably 1 to 12 carbon atoms.

Examples of the alkyl (meth) acrylate include the same compounds as those which can be selected as the monomer (a 1') described later.

Examples of the hydroxyl-modified olefin-based resin obtained by hydroxyl-modifying an olefin-based resin include modified polymers obtained by graft-polymerizing a hydroxyl-containing compound to the above-mentioned unmodified olefin-based resin as a main chain.

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

(resins other than the urethane acrylate resin and the olefin resin)

In one embodiment of the present invention, the resin composition (y) may contain a resin other than the acrylic urethane resin and the olefin resin within a range not to impair the effects of the present invention.

Examples of such resins include: vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymers, and ethylene-vinyl alcohol copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymers; cellulose triacetate; a polycarbonate; polyurethanes that do not belong to the group of acrylic urethane resins; polymethylpentene; polysulfones; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; a polyamide-based resin; acrylic resin; fluorine-based resins, and the like.

Among them, from the viewpoint of forming the expandable base layer (Y1) in which unevenness is easily formed on the surface when the expandable particles expand, it is preferable that the resin composition (Y) contains a small amount of a resin other than the acrylic urethane resin and the olefin resin.

The content of the resin other than the acrylic urethane resin and the olefin resin is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, still more preferably less than 10 parts by mass, yet still more preferably less than 5 parts by mass, and yet still more preferably less than 1 part by mass, based on 100 parts by mass of the total amount of the resins contained in the resin composition (y).

[ solventless resin composition (y1) ]

One embodiment of the resin composition (y) is a solventless resin composition (y1) containing an ethylenically unsaturated group-containing oligomer having a weight average molecular weight (Mw) of 50000 or less, an energy ray polymerizable monomer, and the above thermally expandable particles and containing no solvent.

The solvent-free resin composition (y1) does not contain a solvent, but the energy ray-polymerizable monomer contributes to improvement in plasticity of the oligomer.

By irradiating the coating film formed from the solvent-free resin composition (Y1) with an energy ray, the expandable base layer (Y1) in which unevenness is easily formed on the surface when the expandable particles expand, and particularly, the thermally expandable base layer (Y1-1) satisfying the above conditions (1) and (2) can be easily formed.

The type, shape, and blending amount (content) of the expandable particles blended in the solvent-free resin composition (y1) are the same as those of the resin composition (y), as described above.

The oligomer contained in the solventless resin composition (y1) has a weight average molecular weight (Mw) of 50000 or less, preferably 1000 to 50000, more preferably 2000 to 40000, still more preferably 3000 to 35000, and still more preferably 4000 to 30000.

The oligomer may be any oligomer having an ethylenically unsaturated group with a weight average molecular weight of 50000 or less in the resin contained in the resin composition (y), and is preferably the Urethane Prepolymer (UP).

As the oligomer, a modified olefin-based resin having an ethylenically unsaturated group can be used.

The total content of the oligomer and the energy ray-polymerizable monomer in the solvent-free resin composition (y1) is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, even more preferably 65 to 90% by mass, and even more preferably 70 to 85% by mass, based on the total amount (100% by mass) of the solvent-free resin composition (y 1).

Examples of the energy ray-polymerizable monomer include: alicyclic polymerizable compounds such as isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, adamantyl (meth) acrylate, and tricyclodecanyl acrylate; aromatic polymerizable compounds such as phenyl hydroxypropyl acrylate, benzyl acrylate, and phenol ethylene oxide-modified acrylate; heterocyclic polymerizable compounds such as tetrahydrofurfuryl (meth) acrylate, morpholine acrylate, N-vinylpyrrolidone and N-vinylcaprolactam.

These energy ray-polymerizable monomers may be used alone, or two or more of them may be used in combination.

The blending ratio of the oligomer to the energy ray polymerizable monomer (the oligomer/energy ray polymerizable monomer) is preferably 20/80 to 90/10, more preferably 30/70 to 85/15, and still more preferably 35/65 to 80/20.

In one embodiment of the present invention, the solventless resin composition (y1) is preferably further blended with a photopolymerization initiator.

By containing a photopolymerization initiator, the curing reaction can be sufficiently performed by irradiation with energy rays of relatively low energy.

Examples of the photopolymerization initiator include: 1-hydroxycyclohexyl phenyl ketone, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, bibenzyl, butanedione, 8-chloroanthraquinone, and the like.

These photopolymerization initiators may be used alone or in combination of two or more.

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

< non-expandable substrate layer (Y2) >)

Examples of the material for forming the non-expandable base layer (Y2) constituting the base material (Y) include: paper, resin, metal, and the like.

Examples of the paper include: thin paper, medium paper, high-quality paper, impregnated paper, coated paper, art paper, parchment paper, glassine paper and the like.

Examples of the resin include: polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymers, and ethylene-vinyl alcohol copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymers; cellulose triacetate; a polycarbonate; polyurethane resins such as polyurethane and acrylic modified polyurethane; polymethylpentene; polysulfones; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; a polyamide-based resin; acrylic resin; fluorine-based resins, and the like.

Examples of the metal include: aluminum, tin, chromium, titanium, and the like.

These forming materials may be composed of one kind, or two or more kinds may be used in combination.

Examples of the non-expandable base material layer (Y2) using two or more types of forming materials in combination include a material obtained by laminating paper materials with a thermoplastic resin such as polyethylene, and a material obtained by forming a metal film on the surface of a resin film or sheet containing a resin.

Examples of the method for forming the metal layer include: a method of depositing the above metal by a PVD method such as vacuum deposition, sputtering, or ion plating, or a method of attaching a metal foil made of the above metal using a conventional adhesive, and the like.

In the case where the non-expandable base material layer (Y2) contains a resin, from the viewpoint of improving interlayer adhesion between the non-expandable base material layer (Y2) and another layer to be laminated, the surface of the non-expandable base material layer (Y2) may be subjected to a surface treatment by an oxidation method, a roughening method, or the like, an easy adhesion treatment, or an undercoating treatment, as in the case of the expandable base material layer (Y1).

When the non-expandable substrate layer (Y2) contains a resin, the resin may be contained, and the substrate additive that may be contained in the resin composition (Y) may be contained.

Preferably, the non-expandable substrate layer (Y2) is present at a position farther from the first pressure-sensitive adhesive layer (X1) than the expandable substrate layer (Y1), the non-expandable substrate layer (Y2) is not present between the expandable substrate layer (Y1) and the first pressure-sensitive adhesive layer (X1), and the storage modulus E 'of the non-expandable substrate layer (Y2) when the expandable particles expand is larger than the storage modulus E' of the expandable substrate layer (Y1) when the expandable particles expand. As described above, since the non-expandable base material layer (Y2) is not present between the expandable base material layer (Y1) and the 1 st pressure-sensitive adhesive layer (X1), the irregularities generated on the surface of the expandable base material layer (Y1) by the expansion of the expandable particles are transmitted to the 1 st pressure-sensitive adhesive layer (X1), and the non-expandable base material layer (Y2) is not interposed therebetween, so that the irregularities are likely to be generated also on the bonding surface of the 1 st pressure-sensitive adhesive layer (X1). Further, when the expandable particles expand, since the storage modulus E 'of the non-expandable base material layer (Y2) is larger than the storage modulus E' of the expandable base material layer (Y1), it is possible to suppress the occurrence of irregularities on the surface of the expandable base material layer (Y1) on the non-expandable base material layer (Y2) side when the expandable particles expand, and as a result, the occurrence of irregularities on the surface of the expandable base material layer (Y1) on the 1 st pressure-sensitive adhesive layer (X1) side becomes easy, and therefore, the occurrence of irregularities also on the bonding surface of the 1 st pressure-sensitive adhesive layer (X1) is easy.

As described above, the storage modulus E' of the non-expandable base material layer (Y2) when the expandable particles expand is preferably 1.0MPa or more from the viewpoint of facilitating the formation of irregularities on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1), and is preferably 1.0 × 10 from the viewpoint of facilitating the attachment work and the detachment work, facilitating the formation of irregularities on the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2), or facilitating the handling of the roll product³MPa or less. From this viewpoint, the storage modulus E' of the non-expandable base material layer (Y2) when the expandable particles expand is preferably 1.0 to 5.0 × 10²MPa, more preferably 1.0X 10¹～1.0×10²MPa, more preferably 5.0X 10¹～1.0×10³MPa。

From the above-mentioned viewpoints and from the viewpoint of preventing the occurrence of displacement when the semiconductor wafer is bonded to the bonding surface of the 2 nd pressure-sensitive adhesive layer (X2), the storage modulus E' (23) of the non-expandable base material layer (Y2) at 23 ℃ is preferably 5.0 × 10¹～5.0×10⁴MPa, more preferably 1.0X 10²～1.0×10⁴MPa, more preferably 5.0X 10²～5.0×10³MPa. The non-expandable substrate layer (Y2) is a non-expandable layer determined by the above method.

Therefore, the volume change (%) of the non-expandable substrate layer (Y2) calculated from the above formula is less than 5 vol%, preferably less than 2 vol%, more preferably less than 1 vol%, still more preferably less than 0.1 vol%, and still more preferably less than 0.01 vol%.

The non-expandable base material layer (Y2) may contain thermally expandable particles as long as the volume change rate is within the above range. For example, by selecting the resin contained in the non-expandable base material layer (Y2), the volume change rate can be adjusted to the above range even if the thermally expandable particles are contained.

However, the smaller the content of the thermally expandable particles in the non-expandable base material layer (Y2), the more preferable.

The content of the specific thermally expandable particles is usually less than 3 mass%, preferably less than 1 mass%, more preferably less than 0.1 mass%, still more preferably less than 0.01 mass%, and yet still more preferably less than 0.001 mass% based on the total mass (100 mass%) of the non-expandable base material layer (Y2).

< 1 st adhesive layer (X1), 2 nd adhesive layer (X2) >

The pressure-sensitive adhesive sheet used in one embodiment of the present invention has a1 st pressure-sensitive adhesive layer (X1) and a 2 nd pressure-sensitive adhesive layer (X2) as non-expandable pressure-sensitive adhesive layers.

In the manufacturing method of the present invention, the adhesive surface of the 1 st adhesive layer (X1) is bonded to the hard support, and the object to be sealed is placed on the adhesive surface of the 2 nd adhesive layer (X2), thereby forming a cured sealed body.

By using the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) as non-expandable pressure-sensitive adhesive layers, it is possible to effectively suppress the disadvantages of displacement of the object to be sealed due to insufficient fixation between the object to be sealed and the hard support, and adhesion of the sealing resin to the exposed surface of the object to be sealed.

In addition, by using the non-expandable pressure-sensitive adhesive layer as the 1 st pressure-sensitive adhesive layer (X1), in addition to the above-described effects, it is possible to suppress the occurrence of troubles such as the 1 st pressure-sensitive adhesive layer (X1) coming off in the cured sealant with a pressure-sensitive adhesive sheet separated from the cured support and contaminating various devices in the production environment.

For the 1 st adhesive layer (X1), it is required to have the following properties: before the expandable particles contained in the expandable base layer (Y1) expand, the adhesion to the hard support is high, and the object to be sealed can be sufficiently fixed to the hard support.

From this viewpoint, the shear storage modulus G' (23) of the 1 st adhesive layer (X1) at 23 ℃ is preferably 1.0X 10⁸Pa or less, more preferably 5.0X 10⁷Pa or less, more preferably 1.0X 10⁷Pa or less.

On the other hand, when the expandable particles in the expandable base material layer (Y1) expand, the surface of the expandable base material layer (Y1) is required to have such rigidity that the irregularities formed on the surface of the 1 st pressure-sensitive adhesive layer (X1) can be formed.

From this viewpoint, the shear storage modulus G' (23) of the 1 st adhesive layer (X1) at 23 ℃ is preferably 1.0X 10⁴Pa or more, more preferably 5.0X 10⁴Pa or more, preferably 1.0X 10⁵Pa or above.

The 2 nd pressure-sensitive adhesive layer (X2) is required to have adhesion not only to the object to be sealed but also to a cured seal body obtained by sealing the object to be sealed with a sealing material. Further, it is necessary to suppress the phenomenon that the object to be sealed sinks into the 2 nd pressure-sensitive adhesive layer (X2) excessively.

From these viewpoints, the shear storage modulus G' (23) of the 2 nd adhesive layer (X2) at 23 ℃ is preferably 1.0X 10⁴～1.0×10⁸Pa, more preferably 5.0X 10⁴～5.0×10⁷Pa, more preferably 9.0X 10⁴～1.0×10⁷Pa。

In the present specification, the shear storage modulus G' (23) of the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) is a value measured by the method described in examples.

The thickness of the 1 st adhesive layer (X1) is preferably 1 to 60 μm, more preferably 2 to 50 μm, still more preferably 3 to 40 μm, and still more preferably 5 to 30 μm.

The thickness of the 2 nd adhesive layer (X2) is preferably 1 to 60 μm, more preferably 2 to 50 μm, still more preferably 3 to 40 μm, and still more preferably 5 to 30 μm.

The 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) may be formed of an adhesive composition (X) containing an adhesive resin.

The pressure-sensitive adhesive composition (x) may further contain a pressure-sensitive adhesive additive such as a crosslinking agent, a tackifier, a polymerizable compound, or a polymerization initiator, if necessary.

Hereinafter, each component contained in the adhesive composition (x) will be described.

(adhesive resin)

As the adhesive resin used in one embodiment of the present invention, the resin alone may have adhesive properties and be a polymer having a weight average molecular weight (Mw) of 1 ten thousand or more.

The weight average molecular weight (Mw) of the pressure-sensitive adhesive resin used in one embodiment of the present invention is preferably 1 to 200 ten thousand, more preferably 2 to 150 ten thousand, and even more preferably 3 to 100 ten thousand, from the viewpoint of improving the pressure-sensitive adhesive force.

Specific examples of the adhesive resin include: rubber-based resins such as acrylic resins, urethane-based resins and polyisobutylene-based resins, polyester-based resins, olefin-based resins, silicone-based resins, and polyvinyl ether-based resins.

These adhesive resins may be used alone or in combination of two or more.

When the adhesive resin is a copolymer having two or more kinds of structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer, and a graft copolymer.

The adhesive resin used in one embodiment of the present invention may be an energy ray-curable adhesive resin in which a polymerizable functional group is introduced into a side chain of the adhesive resin.

For example, when the 2 nd adhesive layer (X2) is formed from an energy ray-curable adhesive composition containing an energy ray-curable adhesive resin, the adhesive strength can be reduced by irradiation with an energy ray, and therefore the obtained cured seal can be easily separated from the 2 nd adhesive layer (X2).

Examples of the polymerizable functional group include a (meth) acryloyl group and a vinyl group.

The energy ray includes ultraviolet rays and electron beams, and preferably ultraviolet rays.

The material for forming the pressure-sensitive adhesive layer, which can be irradiated with an energy ray to reduce the adhesive force, may be an energy ray-curable pressure-sensitive adhesive composition containing a monomer or oligomer having a polymerizable functional group.

These energy ray-curable adhesive compositions preferably further contain a photopolymerization initiator.

By containing the photopolymerization initiator, the curing reaction can be sufficiently advanced even by irradiation with energy rays of relatively low energy.

Examples of the photopolymerization initiator include those similar to those blended in the above solventless resin composition (y 1).

The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.05 to 2 parts by mass, per 100 parts by mass of the energy ray-curable adhesive resin or 100 parts by mass of the monomer or oligomer having a polymerizable functional group.

In one embodiment of the present invention, the pressure-sensitive adhesive resin preferably contains an acrylic resin from the viewpoint of exhibiting excellent adhesion. In particular, when the 1 st pressure-sensitive adhesive layer (X1) is formed from a pressure-sensitive adhesive composition containing an acrylic resin, irregularities can be easily formed on the surface of the 1 st pressure-sensitive adhesive layer.

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

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

(crosslinking agent)

In one embodiment of the present invention, when the adhesive composition (x) contains an adhesive resin having a functional group, the adhesive composition (x) preferably further contains a crosslinking agent.

The crosslinking agent is a component that reacts with an adhesive resin having a functional group to crosslink the adhesive resins with each other with the functional group as a crosslinking starting point.

Examples of the crosslinking agent include: isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, and the like.

These crosslinking agents may be used alone, or two or more of them may be used in combination.

Among these crosslinking agents, isocyanate-based crosslinking agents are preferable from the viewpoint of improving cohesive force to improve adhesive force, and from the viewpoint of easiness in acquisition.

The content of the crosslinking agent may be appropriately adjusted depending on the number of functional groups contained in the adhesive resin, but is preferably 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, based on 100 parts by mass of the adhesive resin having functional groups.

(tackifier)

In one embodiment of the present invention, the pressure-sensitive adhesive composition (x) may further contain a tackifier from the viewpoint of further improving the adhesive strength.

In the present specification, the "tackifier" is a component which is different from the above adhesive resin, and is an oligomer having a weight average molecular weight (Mw) of less than 1 ten thousand among components which increase the adhesive force of the above adhesive resin in an auxiliary manner.

The tackifier has a weight average molecular weight (Mw) of preferably 400 to 10000, more preferably 500 to 8000, and further preferably 800 to 5000.

Examples of the tackifier include: rosin-based resins, terpene-based resins, styrene-based resins, C5-based petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1, 3-pentadiene, which are produced by thermal decomposition of naphtha, C9-based petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyl toluene, which are produced by thermal decomposition of naphtha, hydrogenated resins obtained by hydrogenating these resins, and the like.

The softening point of the thickener is preferably 60 to 170 ℃, more preferably 65 to 160 ℃, and further preferably 70 to 150 ℃.

In the present specification, the "softening point" of the tackifier means a value measured in accordance with JIS K2531.

The tackifier may be used alone, or two or more different in softening point, structure, and the like may be used in combination.

Also, in the case where two or more kinds of tackifiers are used, it is preferable that the weighted average of the softening points of the plurality of tackifiers falls within the above range.

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

(additive for adhesive)

In one embodiment of the present invention, the adhesive composition (x) may contain, in addition to the above-mentioned additives, an additive for adhesives used in conventional adhesives within a range not to impair the effects of the present invention.

Examples of such additives for adhesives include: antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction promoters (catalysts), ultraviolet absorbers, antistatic agents, and the like.

These additives for adhesives may be used alone or in combination of two or more.

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

The 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) are both non-expandable adhesive layers, but preferably do not substantially contain expandable particles.

Here, "substantially not containing expandable particles" means that expandable particles are not contained in the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) for a specific purpose. Therefore, the case where the expandable particles are mixed as impurities into the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2) is excluded.

Specifically, the content of the swellable particles is preferably less than 1 mass%, more preferably less than 0.1 mass%, even more preferably less than 0.01 mass%, and even more preferably less than 0.001 mass% with respect to the total amount (100 mass%) of the active ingredients of the binder composition (X) as the material forming the 1 st binder layer (X1) and the 2 nd binder layer (X2), or with respect to the total mass (100 mass%) of the 1 st binder layer (X1) and the 2 nd binder layer (X2).

< stripping Material >

The pressure-sensitive adhesive sheet used in one embodiment of the present invention may further include a release material laminated on the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) and the 2 nd pressure-sensitive adhesive layer (X2).

As the release material, a release sheet subjected to a double-sided release treatment, a release sheet subjected to a single-sided release treatment, or the like can be used, and examples thereof include a material obtained by applying a release agent to a release material substrate.

Examples of the base material for release material include: high quality paper, cellophane, kraft paper and the like; plastic films such as polyester resin films such as polyethylene terephthalate resins, polybutylene terephthalate resins, and polyethylene naphthalate resins, and olefin resin films such as polypropylene resins and polyethylene resins; and so on.

Examples of the release agent include: rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins.

The thickness of the release agent is not particularly limited, but is preferably 10 to 200. mu.m, more preferably 25 to 170. mu.m, and still more preferably 35 to 80 μm.

[ Steps of the method for producing a cured sealing body according to the present invention ]

The method for producing a cured sealing body using the adhesive sheet of the present invention includes the following steps (1) to (3).

Step (2): and a step in which the object to be sealed and the bonding surface of the 2 nd adhesive layer (X2) on at least the peripheral portion of the object to be sealed are covered with a sealing material, and the sealing material is cured to obtain a cured sealing body in which the object to be sealed is sealed with the sealing material.

Fig. 2 is a schematic cross-sectional view of steps (1) to (3) of the method for producing a cured sealing body according to the present invention.

Hereinafter, the steps (1) to (3) will be described with reference to fig. 2 as appropriate.

< Process (1) >

Fig. 2(a) is a schematic cross-sectional view of step (1) in the case of using the adhesive sheet 1a shown in fig. 1 (a).

As shown in fig. 2(a), the step (1) is a step of bonding the adhesive surface of the 1 st adhesive layer (X1) of the adhesive sheet 1a to the rigid support 50 and placing the object to be sealed 60 on a part of the adhesive surface of the 2 nd adhesive layer (X2).

In this step, it is preferable that the object to be sealed 60 is placed on a part of the adhesive surface of the 2 nd adhesive layer (X2) so that the exposed surface 61 is in contact with the adhesive surface.

The number of objects to be sealed placed on a part of the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) may be only one, or may be plural as shown in fig. 2 (a). When a plurality of objects to be sealed are placed, the objects to be sealed are preferably placed so that the interval between adjacent objects to be sealed is constant.

Note that, although fig. 2 shows an embodiment using the adhesive sheet 1a shown in fig. 1(a), when an adhesive sheet having another configuration is used, it is also preferable that the hard support, the adhesive sheet, and the semiconductor chip are laminated or placed in this order, and the adhesive surface of the 1 st adhesive layer (X1) of the adhesive sheet is attached to the hard support, and the adhesive surface of the 2 nd adhesive layer (X2) is attached to the exposed surface of the object to be sealed.

The step (1) is preferably performed in an environment in which the expandable particles do not expand.

For example, when thermally expandable particles are used as the expandable particles, the step (1) may be performed at a temperature lower than the expansion start temperature (t) of the thermally expandable particles, and specifically, preferably performed in an environment of 0 to 80 ℃ (in a case where the expansion start temperature (t) is 60 to 80 ℃, in an environment lower than the expansion start temperature (t)).

The hard support is preferably attached to the entire surface of the pressure-sensitive adhesive surface of the 1 st pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet. Therefore, the hard support is preferably plate-shaped.

As shown in fig. 2, the surface area of the hard support to which the 1 st pressure-sensitive adhesive layer (X1) is bonded is preferably equal to or larger than the surface area of the 1 st pressure-sensitive adhesive layer (X1) to which it is bonded.

Examples of the material constituting the hard support include: metal materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; epoxy resin, ABS resin, acrylic resin, engineering plastic, special engineering plastic, polyimide resin, polyamide-imide resin and other resin materials; and composite materials such as glass epoxy resins, and among these, SUS, glass, and silicon wafers are preferable.

The engineering plastics include: nylon, Polycarbonate (PC), and polyethylene terephthalate (PET).

As the special engineering plastics, there may be mentioned: polyphenylene Sulfide (PPS), polyether sulfone (PES), and polyether ether ketone (PEEK).

The thickness of the hard support is preferably 20 μm or more and 50mm or less, and more preferably 60 μm or more and 20mm or less.

The young's modulus of the hard support is preferably 1.0GPa or more, more preferably 5.0GPa or more, further preferably 10GPa or more, and still further preferably 20GPa or more, from the viewpoint of sufficiently fixing the semiconductor chip to the hard support and effectively suppressing the occurrence of misalignment of the object to be sealed and adhesion of the sealing resin to the exposed surface of the object to be sealed in step (2).

In the present specification, the Young's modulus of the rigid support is a value measured at room temperature (25 ℃ C.) according to the static Young's modulus test method of JIS Z2280: 1993.

On the other hand, examples of the object to be sealed placed on a part of the adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) include: semiconductor chips, semiconductor wafers, compound semiconductors, semiconductor packages, electronic components, sapphire substrates, displays, panel substrates, and the like.

The sealing object to be placed may be composed of the same kind of material, or may be composed of 2 or more different kinds of materials.

The exposed surface of the object to be sealed is a surface which is in contact with the adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) and is covered with the sealing material, and specifically corresponds to a circuit surface.

In the manufacturing method of the present invention, since the object to be sealed is sufficiently fixed to the rigid support, it is possible to effectively suppress the adhesion of the sealing resin to the exposed surface of the object to be sealed in the sealing step of step (2). For example, if the sealing resin adheres to the circuit surface, the wiring of the circuit is broken, which causes a reduction in the yield.

Examples of a method for placing the object to be sealed include: a pick-and-place method using a flip chip welder, a chip mounter and the like, and a one-time transfer printing method using a transfer printing device.

The arrangement, number of arrangement, and the like of the objects to be sealed may be determined as appropriate depending on the form, number of production, and the like of the target package.

The cured seal produced by the production method of the present invention is preferably used for FOWLP. Therefore, the object to be sealed is preferably a semiconductor chip.

As the semiconductor chip, those conventionally known can be used, and a semiconductor chip in which an integrated circuit including circuit elements such as transistors, resistors, and capacitors is formed on a circuit surface thereof can be used.

A semiconductor chip used in one embodiment of the present invention can be obtained by dicing a semiconductor wafer in which a circuit is formed by an etching method, a lift-off (lift-off) method, or the like on one surface of a substrate made of silicon, SiC (silicon carbide), gallium, arsenic, or the like.

The method for obtaining semiconductor chips from a semiconductor wafer may be a stealth dicing method, a pre-dicing method, or a method other than these methods.

The exposed surface of the semiconductor chip placed on the adhesive surface of the 2 nd adhesive layer (X2) is preferably a circuit surface on which a circuit is formed.

By placing the circuit surface of the semiconductor chip on the adhesive surface of the 2 nd adhesive layer (X2), the circuit surface of the semiconductor chip can be protected during the process of step (2).

On the other hand, the surface of the semiconductor chip opposite to the circuit surface (hereinafter also referred to as "back surface") is the surface coated with the sealing material in the subsequent step, and is usually a flat surface on which no circuit, electrode, or the like is formed.

Here, as in FOWLP, FOPLP, or the like, it is preferable to apply the semiconductor chip to a package in which a region larger than the chip size is covered with an encapsulating material, and a rewiring layer is formed not only on the circuit surface of the semiconductor chip but also on the surface region of the encapsulating material.

Therefore, the semiconductor chips are mounted on a part of the bonding surface of the 2 nd adhesive layer (X2), preferably the plurality of semiconductor chips are mounted on the bonding surface with a constant interval therebetween, and more preferably the plurality of semiconductor chips are mounted on the bonding surface with a constant interval therebetween and arranged in a matrix of a plurality of rows and a plurality of columns.

The distance between the semiconductor chips may be determined as appropriate depending on the form of the target package.

< Process (2) >

As shown in fig. 2 b, the step (2) is a step of coating the object to be sealed 60 and the adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) at least in the peripheral portion of the object to be sealed 60 with a sealing material 70 (hereinafter, also referred to as "coating treatment"), and curing the sealing material 70 (hereinafter, also referred to as "curing treatment") to obtain a cured sealing body 80 in which the object to be sealed 60 is sealed with the sealing material 70.

In the coating treatment in step (2), when the entire exposed surface of the object to be sealed is coated with the sealing material and a plurality of objects to be sealed are placed thereon, the sealing material is preferably coated so as to fill the gap between the objects to be sealed.

As shown in fig. 2(b), the object to be sealed 60 and the 2 nd pressure-sensitive adhesive layer (X2) may be coated with the sealing material 70 so that the entire bonding surface is coated.

The sealing material has a function of protecting the object to be sealed and its accompanying elements from the external environment.

The sealing material used in the production method of the present invention is preferably a thermosetting sealing material containing a thermosetting resin from the viewpoint of workability.

The sealing material may be a solid material in the form of particles, beads, films, or the like at room temperature, or may be a liquid material in the form of a composition, but from the viewpoint of workability, a film-shaped sealing material, that is, a sealing resin film is preferable.

The coating method may be selected from conventional methods used in a sealing step and used according to the type of the sealing material.

Specific coating methods include, for example: roll lamination, vacuum pressing, vacuum lamination, spin coating, die coating, transfer molding, compression molding, and the like.

The coating treatment and the curing treatment in the step (2) are preferably performed in an environment in which the expandable particles do not expand.

For example, when thermally expandable particles are used as the expandable particles, the step (2) may be performed under a temperature condition lower than the expansion start temperature (t) of the thermally expandable particles, and specifically, preferably performed in an environment of 0 to 80 ℃ (in a case where the expansion start temperature (t) is 60 to 80 ℃, in an environment lower than the expansion start temperature (t)).

After the coating treatment, the sealing material is cured to obtain a cured sealing body in which the object to be sealed is sealed with the sealing material.

The coating step and the thermosetting step may be performed separately, but when the sealing material is heated in the coating step, the sealing material may be directly thermally cured by the heating, and the coating step and the thermosetting step may be performed simultaneously.

< Process (3) >

The step (3) is a step of expanding the expandable particles and separating the expandable particles from the interface P between the hard support and the 1 st pressure-sensitive adhesive layer (X1) in a state where the cured sealing material is laminated on the 2 nd pressure-sensitive adhesive layer (X2).

Fig. 2(c) shows a state in which the expandable particles in the expandable base material layer (Y1) are expanded and separated at the interface P between the hard support 50 and the 1 st pressure-sensitive adhesive layer (X1).

In this step, the method for swelling the swellable particles can be appropriately selected depending on the type of the swellable particles.

For example, when thermally expandable particles are used as the expandable particles, the thermally expandable particles are expanded by performing a heat treatment at a temperature equal to or higher than the expansion starting temperature (t) of the thermally expandable particles.

In this case, the "temperature not lower than the expansion start temperature (t)" is preferably not lower than the "expansion start temperature (t) +10 ℃ and not higher than the" expansion start temperature (t) +60 ℃, and more preferably not lower than the "expansion start temperature (t) +15 ℃ and not higher than the" expansion start temperature (t) +40 ℃ ".

In the production method of the present invention, the adhesive sheet having the expandable base material layer (Y1) containing expandable particles is used and adjusted so that the expansion of the expandable particles can form irregularities on the adhesive surface of the 1 st adhesive layer (X1) adhered to the hard support, thereby enabling separation at the interface P between the hard support and the 1 st adhesive layer (X1).

Therefore, contamination of the hard support such as remaining of a part of the 1 st adhesive layer (X1) on the surface of the hard support after separation can be suppressed, and the hard support can be cleaned without a cleaning step, thereby improving productivity.

In addition, in this step, it is preferable that the expandable particles are expanded so as not to cause separation between layers constituting the adhesive sheet.

That is, as shown in fig. 2(c), it is preferable that a part of the layer of the adhesive sheet is removed by the step (3) without remaining on the surface of the rigid support 50.

In general, the hard support from which the adhesive sheet has been separated is subjected to the same process by re-attaching a new adhesive sheet. In this case, if the layers constituting the adhesive sheet are separated from each other and a part of the layer of the adhesive sheet remains on the surface of the hard support, a step for removing the layer is required.

On the other hand, in this step, when the expandable particles are expanded, the interlayer of each layer constituting the adhesive sheet is not separated, and therefore the above-mentioned problem does not occur, and the productivity of producing a cured sealant can be further improved

In addition, in the cured sealant with the psa sheet after separation, since the 1 st psa layer (X1) located at the outermost layer of the psa sheet is a non-expandable psa layer, disadvantages such as the 1 st psa layer (X1) becoming detached are not likely to occur. From this point of view, the problem of contamination in the manufacturing environment is suppressed, and this becomes a factor for further improving productivity.

In addition, the cured sealing body obtained after removing the adhesive sheet effectively suppresses the occurrence of misalignment of the object to be sealed and the adhesion of the sealing resin to the exposed surface of the object to be sealed.

Therefore, according to the manufacturing method of the present invention, the yield in manufacturing such a cured sealing body can be improved.

The obtained cured sealing body may be subjected to a step of grinding the sealing material of the cured sealing body until the surface of the object to be sealed is exposed, a step of rewiring the circuit surface, a step of forming external electrode pads and then connecting the external electrode pads to the external terminal electrodes, and the like.

Further, the external terminal electrode may be connected to the cured sealing body and then singulated to manufacture the semiconductor device.

Examples

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

< weight average molecular weight (Mw) >)

The measurement was carried out under the following conditions using a gel permeation chromatography apparatus (product name "HLC-8020" available from Tosoh corporation) and the value was measured in terms of standard polystyrene.

(measurement conditions)

Column chromatography: a chromatographic column formed by sequentially connecting TSK guard column HXL-L, TSK gel G2500HXL, TSK gel G2000HXL and TSK gel G1000HXL (all manufactured by Tosoh Corp.) in sequence

Column temperature: 40 deg.C

Developing solvent: tetrahydrofuran (THF)

Flow rate: 1.0mL/min

< average particle diameter of Expandable particles, 90% particle diameter (D)₉₀) Measurement of

The particle distribution of the target expandable particles was measured using a laser diffraction particle size distribution measuring apparatus (for example, a Mastersizer3000 manufactured by Malvern).

Then, based on the particle distribution, the particle diameter having a cumulative volume frequency of 50% calculated from the particles having a small particle diameter among the expandable particles is referred to as "average particle diameter", and the particle diameter having a cumulative volume frequency of 90% is referred to as "90% particle diameter (D)₉₀)”。

< measurement of thickness of each layer >

The measurement was carried out using a constant-pressure thickness gauge (model: "PG-02J", Standard: based on JIS K6783, Z1702 and Z1709) manufactured by TECCLOCK.

< storage modulus E' of the thermally expandable base material layer (Y1)

The resultant thermally expandable base layer (Y1) was sized to be 5mm in length by 30mm in width by 200 μm in thickness, and the release material was removed, and the resultant material was used as a test sample.

The storage modulus E' of the test sample at a given temperature was measured using a dynamic viscoelasticity measuring apparatus (product name "DMAQ 800" manufactured by TA INSTRUMENTS Co., Ltd.) under conditions of a test initiation temperature of 0 ℃, a test completion temperature of 300 ℃, a temperature rise rate of 3 ℃/min, a frequency of 1Hz, and an amplitude of 20 μm.

< storage elastic modulus G' >, of the 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2)

The 1 st adhesive layer (X1) and the 2 nd adhesive layer (X2) thus formed were cut into a circular shape having a diameter of 8mm, and then the release material was removed and the resultant was laminated to prepare a sample having a thickness of 3mm, which was used as a test sample.

The shear storage modulus G' of the test sample at a given temperature was measured by the torsional shear method using a viscoelasticity measuring apparatus (manufactured by Anton Paar, Inc., under the apparatus name "MCR 300") under conditions of a test start temperature of 0 ℃, a test end temperature of 300 ℃, a temperature rise rate of 3 ℃/min, and a frequency of 1 Hz.

< Probe viscosity number >

The substrate layer to be measured was cut into a square having a side length of 10mm, and then left to stand in an atmosphere of 23 ℃ and 50% RH (relative humidity) for 24 hours, and the obtained sample was used as a test sample.

The probe tack value of the surface of the test sample was measured in an environment of 23 ℃ and 50% RH (relative humidity) by using a tack tester (product name "NTS-4800" manufactured by Nippon Special instruments Co., Ltd.) in accordance with JIS Z0237: 1991.

Specifically, a probe made of stainless steel having a diameter of 5mm was subjected to a contact load of 0.98N/cm for 1 second²After contacting with the surface of the test sample, the force required to separate the probe from the surface of the test sample at a speed of 10 mm/sec was measured, and the obtained value was taken as the probe tack value of the test sample.

< measurement of adhesive force of No. 2 adhesive layer (X2) >

A PET film (product name "COSMOSHINE A4100" available from Toyo Boseki K.K.) having a thickness of 50 μm was laminated on the pressure-sensitive adhesive surface of the 2 nd pressure-sensitive adhesive layer (X2) formed on the release film to prepare a pressure-sensitive adhesive sheet with a substrate.

Then, the release film was removed, the adhesive surface of the exposed 2 nd adhesive layer (X2) was adhered to a stainless steel plate (SUS 304360) as an adherend, and after standing for 24 hours in an environment of 23 ℃ and 50% RH (relative humidity), the adhesive force at 23 ℃ was measured in the same environment at a tensile rate of 300 mm/min based on JIS Z0237:2000 by a 180 ° peel method.

< Young's modulus of rigid support >

The measurement was carried out at room temperature (25 ℃ C.) based on the static Young's modulus test method of JIS Z2280: 1993.

Production example 1 (Synthesis of urethane acrylate resin)

(1) Synthesis of urethane prepolymer

In a reaction vessel under a nitrogen atmosphere, isophorone diisocyanate was added to 100 parts by mass (solid content ratio) of a polycarbonate diol having a weight average molecular weight of 1,000 so that the equivalent ratio of the hydroxyl group of the polycarbonate diol to the isocyanate group of the isophorone diisocyanate was 1/1, then 160 parts by mass of toluene was added, and the reaction was allowed to proceed at 80 ℃ for 6 hours or more while stirring under a nitrogen atmosphere until the isocyanate group concentration reached the theoretical amount.

Subsequently, a solution prepared by diluting 1.44 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA) with 30 parts by mass of toluene was added thereto, and the reaction was further carried out at 80 ℃ for 6 hours until the isocyanate groups at both ends disappeared to obtain a urethane prepolymer having a weight average molecular weight of 2.9 ten thousand.

(2) Synthesis of acrylic urethane resin

100 parts by mass (solid content ratio) of the urethane prepolymer obtained in production example 1, 117 parts by mass (solid content ratio) of Methyl Methacrylate (MMA), 5.1 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA), 1.1 parts by mass of 1-thioglycerol (solid content ratio), and 50 parts by mass of toluene were charged into a reaction vessel under a nitrogen atmosphere, and the temperature was raised to 105 ℃ with stirring.

Then, a solution prepared by diluting 2.2 parts by mass (solid content ratio) of a radical initiator (product name "ABN-E" manufactured by Nippon Seiko Kabushiki Kaisha) with 210 parts by mass of toluene was further added dropwise to the reaction vessel over 4 hours while keeping the temperature at 105 ℃.

After completion of the dropwise addition, the reaction was carried out at 105 ℃ for 6 hours to obtain a solution of an acrylic urethane resin having a weight-average molecular weight of 10.5 ten thousand.

Production example 2 (preparation of adhesive sheet)

In the following production of the pressure-sensitive adhesive sheet, the details of the pressure-sensitive adhesive resin, the additive, the thermally expandable particles, the substrate and the release agent used for forming each layer are as follows.

< adhesive resin >

The adhesive resin, additive, thermally expandable particles, base material and release agent used for forming each layer in the production of the adhesive sheet described below are described in detail below.

< adhesive resin >

Acrylic copolymer (i): an acrylic copolymer having Mw60 ten thousand structural units derived from a raw material monomer composed of 2-ethylhexyl acrylate (2 EHA)/2-hydroxyethyl acrylate (HEA) at a mass ratio of 80.0/20.0.

Acrylic copolymer (ii): an acrylic copolymer having Mw60 ten thousand structural units derived from a raw material monomer composed of n-Butyl Acrylate (BA)/Methyl Methacrylate (MMA)/2-hydroxyethyl acrylate (HEA)/acrylic acid (mass ratio) of 86.0/8.0/5.0/1.0.

< additives >

Isocyanate crosslinking agent (i): product name "Coronate L" manufactured by tokyo corporation, solid content concentration: 75% by mass.

< thermally expandable particles >

Thermally expandable particles (i): manufactured by Kureha under the name of "S2640", expansion initiation temperature (t) of 208 ℃ and average particle diameter before expansion at 23 ℃ (D)₅₀) Particle size of 90% (D) before swelling at 23 ℃ ═ 24 μm₉₀)＝49μm。

< stripping Material >

Heavy release film: "SP-PET 382150" manufactured by lindecco corporation, a material in which a release agent layer formed of a silicone release agent is provided on one surface of a polyethylene terephthalate (PET) film, and the thickness: 38 μm.

Light release film: "SP-PET 381031" manufactured by Lindelco corporation, having a release agent layer formed of a silicone release agent provided on one surface of a PET film, and having a thickness: 38 μm.

(1) Formation of adhesive layer No. 1 (X1)

An adhesive composition having a solid content (effective component concentration) of 25 mass% was prepared by adding 5.0 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i) to 100 parts by mass of the solid content of the acrylic copolymer (i) as an adhesive resin, diluting with toluene, and stirring until uniform.

Then, the pressure-sensitive adhesive composition was applied to the surface of the release agent layer of the heavy release film to form a coating film, and the coating film was dried at 100 ℃ for 60 seconds to form a1 st pressure-sensitive adhesive layer (X1) as a non-expandable pressure-sensitive adhesive layer having a thickness of 5 μm.

Wherein the 1 st adhesive layer (X1) has a shear storage modulus G' (23) of 2.5X 10 at 23 deg.C⁵Pa。

(2) Formation of 2 nd adhesive layer (X2)

The isocyanate-based crosslinking agent (i) was added in an amount of 0.8 parts by mass (solid content ratio) to 100 parts by mass of the solid content of the acrylic copolymer (ii) as an adhesive resin, diluted with toluene, and stirred until uniform, thereby preparing an adhesive composition having a solid content concentration (effective component concentration) of 25% by mass.

Then, the pressure-sensitive adhesive composition was applied to the surface of the release agent layer of the light release film to form a coating film, and the coating film was dried at 100 ℃ for 60 seconds to form a 2 nd pressure-sensitive adhesive layer (X2) having a thickness of 10 μm.

Wherein the 2 nd adhesive layer (X2) has a shear storage modulus G' (23) of 9.0X 10 at 23 deg.C³Pa。

The adhesive force of the 2 nd adhesive layer (X2) measured by the above method was 1.0N/25 mm.

The probe tack values of the 2 nd adhesive layer (X2) and the 1 st adhesive layer (X1) were significantly 50mN/5mm Φ or more, and therefore measurement of the probe tack values was omitted.

(3) Production of base Material (Y)

To 100 parts by mass of the solid content of the acrylic urethane resin obtained in production 1, 6.3 parts by mass (solid content ratio) of an isocyanate-based crosslinking agent (i), 1.4 parts by mass (solid content ratio) of tin dioctylbis (2-ethylhexanoate) as a catalyst, and the thermally expandable particles (i) were mixed, diluted with toluene, and stirred until uniform, to prepare a resin composition having a solid content (effective component concentration) of 30% by mass.

Wherein the content of the thermally expandable particles (i) is 20% by mass based on the total amount (100% by mass) of the active ingredients in the obtained resin composition.

Then, the resin composition was applied to the surface of a polyethylene terephthalate (PET) film (product name: COSMOSHINE A4100, manufactured by Toyo chemical Co., Ltd., probe tack value: 0mN/5 mm. phi.) having a thickness of 50 μm as a non-swelling substrate to form a coating film, and the coating film was dried at 100 ℃ for 120 seconds to form a swelling substrate layer (Y1) having a thickness of 50 μm.

Here, the PET film corresponds to the non-expandable base material layer (Y2).

As a sample for measuring the physical property value of the expandable base material layer (Y1), a coating film was formed by applying the resin composition to the surface of the release agent layer of the light release film, and the coating film was dried at 100 ℃ for 120 seconds, thereby similarly forming an expandable base material layer (Y1) having a thickness of 50 μm.

Then, the storage modulus and the probe tack value at each temperature of the expandable base material layer (Y1) were measured by the above-mentioned measurement methods, and the measurement results are as follows.

Storage modulus at 23 ℃ E' (23) ═ 2.0X 10⁸Pa

Storage modulus at 208 ℃ E' (208) ═ 5.0X 10⁵Pa

Viscosity value of probe 0mN/5mm phi

The storage modulus and the probe tack value at each temperature of the PET film, i.e., the non-expandable base layer (Y2) were measured, and the measurement results are as follows.

Storage modulus at 23 ℃ E' (23) ═ 1.0X 10³MPa

Storage modulus at 208 ℃ E' (208) ═ 0.8X 10²MPa

Viscosity value of probe 0mN/5mm phi

(4) Lamination of layers

The non-expandable base material layer (Y2) of the base material (Y1) produced in (1-3) was bonded to the 2 nd pressure-sensitive adhesive layer (X2) formed in (2) above, and the thermally expandable base material layer (Y1) was bonded to the 1 st pressure-sensitive adhesive layer (X1) formed in (1) above.

Then, a pressure-sensitive adhesive sheet was produced by laminating a heavy release film/1 st pressure-sensitive adhesive layer (X1)/swellable base material layer (Y1)/non-swellable base material layer (Y2)/2 nd pressure-sensitive adhesive layer (X2)/light release film in this order.

The peel force (F) of the pressure-sensitive adhesive sheet thus produced was measured in the following manner based on the above method₀) And (F)₁)。

As a result, the peeling force (F)₀) 0.23N/25mm, peel force (F)₁) 0mN/25mm, peeling force (F)₁) And peel force (F)₀) Ratio of [ (F)₁)/(F₀)]Is 0.

< peeling force (F)₀) Measurement of

The pressure-sensitive adhesive sheet thus produced was left to stand in an atmosphere of 23 ℃ and 50% RH (relative humidity) for 24 hours, and then the heavy release film of the pressure-sensitive adhesive sheet was removed, and the exposed 1 st pressure-sensitive adhesive layer (X1) was attached to a silicon wafer.

Subsequently, the end of the silicon wafer to which the adhesive sheet was attached was fixed to a lower chuck of a universal tensile testing machine (product name "TENSILON UTM-4-100", manufactured by Orientec corporation), and the adhesive sheet was fixed to an upper chuck.

Then, the peel force measured when peeling was performed at a tensile rate of 300 mm/min at the interface P between the silicon wafer and the 1 st pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet by a 180 ℃ peeling method in the same environment as described above based on JIS Z0237:2000 was taken as "peel force (F1)"₀)”。

< peeling force (F)₁) Measurement of

The heavy release film of the pressure-sensitive adhesive sheet thus prepared was removed, and the exposed 1 st pressure-sensitive adhesive layer (X1) was attached to a silicon wafer, and heated at 240 ℃ for 3 minutes to expand the heat-expandable particles in the expandable base layer (Y1).

Then, the above-mentioned peeling force (F) is applied₀) Similarly, the peel force measured when peeling at the interface P between the silicon wafer and the 1 st pressure-sensitive adhesive layer (X1) of the pressure-sensitive adhesive sheet under the above conditions was defined as "peel force (F)₁)”。

In addition, the peeling force (F)₁) When the pressure-sensitive adhesive sheet (I) is completely separated from the silicon wafer and the pressure-sensitive adhesive sheet (I) cannot be fixed, the measurement of (1) is terminated and the peel force (F) at that time is measured₁) The sample was regarded as "0 mN/25 mm".

Example 1

< Process (1) >

The adhesive sheet produced in production example 2 was cut into a square size of 230mm × 230 mm.

The heavy release film of the cut adhesive sheet was peeled off using a tape laminating machine for back grinding (manufactured by Lindco corporation, device name "RAD-3510F/12"), and the exposed adhesive surface of the 1 st adhesive layer (X1) was adhered to a hard support (material: silicon, thickness: 725 μm, Young's modulus: 30 GPa). Then, the light release film was further peeled off, and 9 semiconductor chips (each having a rectangular parallelepiped shape with a length of 6.4mm × 6.4 × a thickness of 200 μm (# 2000)) were mounted on the exposed adhesive surface of the 2 nd adhesive layer (X2) with a predetermined interval so that the circuit surface on which the circuit was formed was in contact with the adhesive surface.

< Process (2) >

The adhesive surfaces of 9 semiconductor chips and the 2 nd adhesive layer (X2) on at least the peripheral portions of the semiconductor chips were coated with a thermosetting sealing resin film as a sealing material, and the sealing resin film was thermally cured by using a vacuum heat and pressure laminator ("7024 HP 5" manufactured by ROHM and HAAS corporation) to produce a cured sealed body in which the semiconductor chips were sealed with the sealing material.

The sealing conditions were as follows.

Preheating temperature: the operating table and the diaphragm are all 100 DEG C

Vacuum suction: 60 seconds

Dynamic printing mode: 30 seconds

Static pressure mode: 10 seconds

Sealing temperature: 60 minutes at 180 DEG C

When the semiconductor chip was coated with the sealing resin film, no misalignment of the semiconductor chip was observed.

< Process (3) >

The temperature in the system comprising the hard support, the adhesive sheet and the cured sealing body was set to 240 ℃ or higher, which is the expansion initiation temperature (208 ℃) of the thermally expandable particles (i), and the heat treatment was performed at the same temperature for 3 minutes.

After the heat treatment, the hard support and the 1 st adhesive layer (X1) were easily separated at one time at the interface. At this time, the cured sealant was kept in a state of being laminated on the 2 nd pressure-sensitive adhesive layer (X2), and no separation occurred between the layers constituting the pressure-sensitive adhesive sheet.

Therefore, it is considered that the surface of the hard support after the separation of the pressure-sensitive adhesive sheet had no residue of the 1 st pressure-sensitive adhesive layer (X1) and no contamination was observed, and that a new cleaning step for the surface of the hard support was not necessary.

In addition, the obtained semiconductor chip sealed in the cured sealing body was not displaced, and the adhesion of the sealing resin was not observed on the circuit surface.

In addition, with respect to the cured seal with the pressure-sensitive adhesive sheet after separation from the rigid support, no adverse effect such as peeling of the 1 st pressure-sensitive adhesive layer (X1) located at the outermost layer of the pressure-sensitive adhesive sheet was observed, and it can be said that the occurrence of contamination in the production environment was suppressed.

Claims

1. A method for producing a cured sealing body by using an adhesive sheet,

2. The method for producing a cured seal according to claim 1,

3. The method for producing a cured seal according to claim 1,

4. The method for producing a cured seal according to claim 1 or 2, wherein,

5. The method for producing a cured seal according to any one of claims 1 to 4, wherein,

6. The method for producing a cured seal according to any one of claims 1 to 5, wherein,

7. The method for producing a cured seal according to claim 6,

8. The method for producing a cured seal according to claim 6 or 7,

9. The method for producing a cured seal according to any one of claims 1 to 8, wherein,

10. The method for producing a cured seal according to any one of claims 1 to 9, wherein,

the object to be sealed is a semiconductor chip.