KR20190133167A - Adhesive sheet - Google Patents

Abstract

The heat-expandable base material is a pressure-sensitive adhesive sheet comprising a resin and a heat-expandable particle having an expansion start temperature (t) of 120 to 250 ° C., a non-tacky heat-expandable base material, and a pressure-sensitive adhesive layer containing an adhesive resin. The adhesive sheet which satisfy | fills 1)-(2) is provided. The said adhesive sheet can be easily peeled off with a weak force at the time of peeling, suppressing the sedimentation of the said object at the time of heating, when fixing the object temporarily. Requirements (1): The storage elastic modulus (E ') 100 of the thermally expandable substrate at 100 ° C. is 2.0 × 10 ⁵ Pa or more. Requirement (2): The storage modulus (E ') (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles.

Description

Adhesive sheet

The present invention relates to an adhesive sheet.

The adhesive sheet may be used not only for semi-permanently fixing the member but also for temporary fixing for temporarily fixing these materials when processing building materials, interior materials, electronic parts, and the like.

Such a temporary fixing adhesive sheet requires both adhesiveness at the time of use and peelability after use.

For example, Patent Literature 1 discloses a heat-peelable pressure-sensitive adhesive sheet for temporary fixing at the time of cutting an electronic component, in which a heat-expandable pressure-sensitive adhesive layer containing thermally expandable microspheres is provided on at least one surface of the base material. Is disclosed.

This heat-peelable adhesive sheet adjusts the maximum particle diameter of thermally expansible microsphere with respect to the thickness of a thermally expansible adhesive layer, and adjusts the centerline average roughness of the surface of a thermally expansible adhesive layer before heating to 0.4 micrometer or less.

In the patent document 1, the said heat-peelable adhesive sheet can ensure the contact area with a to-be-adhered body at the time of an electronic component cutting, and can exhibit the adhesiveness which can prevent adhesive defects, such as chip scattering, After use, there is a substrate that can be easily peeled off by expanding the thermally expandable microspheres by heating to reduce the contact area with the adherend.

Patent Document 1: Japanese Patent No. 3594853

In recent years, miniaturization, thinning, and high-density electronic devices have progressed, and miniaturization, thinning, and high-density have also been demanded for semiconductor devices mounted in electronic devices. FOWLP (Fan 수 outLPWafer Leｖel Package) has attracted attention as a semiconductor package technology capable of responding to such a demand.

As shown in FIG. 3, the FOWLP 50 provides a redistribution layer 53 on the surface of the semiconductor chip 51 encapsulated by the encapsulation resin layer 52, and solder balls through the redistribution layer 53. It is a semiconductor package in which the 54 and the semiconductor chip 51 are electrically connected.

As shown in FIG. 3, since the FOWLP 50 can fan out the terminal which is the solder ball 54 to the outer side of the semiconductor chip 51, the number of terminals compared with the area of the semiconductor chip 51 is reduced. It can be applied to many applications.

By the way, in the manufacturing process of FOWLP, the sealing resin of the state which has the fluidity | liquidity which mounted the semiconductor chip on the adhesive sheet and heated to 100 degreeC back and forth is (1) adhesion of the semiconductor chip and the surroundings of the said semiconductor chip. The sealing process of (1) or (2) which fills on the surface of a sheet, heats, forms the layer which consists of sealing resin, or (2) laminates the resin film for sealing on a semiconductor chip, and heats and laminates. This is done. After the sealing step, the adhesive sheet is removed, and a FOWLP is manufactured by a step of forming a redistribution layer and solder balls on the surface of the exposed semiconductor chip side.

In the pressure-sensitive adhesive sheet used in the above sealing step, the positional shift of the semiconductor chip does not occur until after the semiconductor chip is placed and sealed with the sealing resin, and the sealing resin does not intrude at the adhesive interface between the semiconductor chip and the pressure-sensitive adhesive sheet. A degree of adhesion is required. On the other hand, after sealing, the peelability which can remove an adhesive sheet easily is calculated | required.

In the sealing process of the manufacturing method of said FOWLP, when using the heat-peelable adhesive sheet in which the thermally expansible adhesion layer containing thermally expansible microsphere was provided on the base material as described, for example in patent document 1, it is also considered. do.

However, according to the examination of the present inventors, when the adhesive sheet of patent document 1 is used for the said sealing process, the elasticity modulus of a thermally expansible adhesive layer falls by the heating in a sealing process, and the semiconductor chip which has been mounted is placed to the adhesive sheet side. It was found that it settled.

If the sealing resin is cured while the semiconductor chip is settled to the adhesive sheet side, the surface of the semiconductor chip side including the sealing resin after removing the adhesive sheet has a level difference between the surface of the semiconductor chip and the surface of the sealing resin, resulting in inferior flatness. . In addition, the misalignment of the semiconductor chips may occur, and the disadvantage may be that the distance between the chips is not constant.

Moreover, when removing the adhesive sheet of patent document 1, even if it heats and expands a thermally expansible adhesive layer, the case where peeling becomes difficult without an external force of a certain magnitude is also considered because a semiconductor chip settles to the adhesive sheet side.

In addition, such a problem is not limited to the sealing process of the manufacturing method of FOWLP, For example, it is a problem which may arise also in the manufacturing process of PSP (panel scale package), and heat-processes, fixing an object to an adhesive sheet, and performing it. This is a concern that may arise in the process.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pressure-sensitive adhesive sheet which can be easily peeled off with a weak force during peeling while suppressing sedimentation of the object during heating when the object is temporarily fixed. do.

MEANS TO SOLVE THE PROBLEM The present inventors set it as the structure of the adhesive sheet which consists of an adhesive layer which contains a resin and thermally expansible particle | grains, and is a non-tacky thermally expansible base material, and adhesive resin, and stores at the predetermined temperature of the said thermally expandable base material. It was found that the above problems can be solved by adjusting the elastic modulus E 'to a specific range.

That is, the present invention relates to the following [1] to [12].

 [1] An adhesive sheet comprising a resin, a thermally expandable particle having an expansion start temperature (t) of 120 to 250 ° C., a non-tacky thermally expandable substrate, and an adhesive layer comprising an adhesive resin, wherein the thermally expandable substrate is The adhesive sheet which satisfy | fills the following requirements (1)-(2).

Requirement (1): The storage elastic modulus (Ek) 100 of the thermally expandable substrate is 100 × 10 ⁵ Pa or more at 100 ° C.

Requirement (2): The storage elastic modulus (E) (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles.

 [2] The adhesive sheet according to the above [1], wherein the thermally expandable base material satisfies the following requirement (3).

Requirements (3): The storage elastic modulus (E ′) 23 of the thermally expandable substrate at 23 ° C. is 1.0 × 10 ⁶ Pa or more.

 [3] The pressure-sensitive adhesive sheet according to the above [1] or [2], wherein a ratio (heat-expandable base material / adhesive layer) of the thickness of the heat-expandable base material and the pressure-sensitive adhesive layer at 23 ° C is 0.2 or more.

 [4] The pressure sensitive adhesive sheet according to any one of [1] to [3], wherein the thermally expandable substrate has a thickness of 10 to 1000 µm and a thickness of the adhesive layer of 1 to 60 µm at 23 ° C.

 [5] The pressure sensitive adhesive sheet according to any one of [1] to [4], wherein a probe tack value on the surface of the thermally expandable substrate is less than 50 mN / 5 mmφ.

[6] The pressure sensitive adhesive sheet according to any one of [1] to [5], wherein the storage shear modulus (G ′) 23 of the pressure sensitive adhesive layer is 1.0 × 10 ⁴ to 1.0 × 10 ⁸ Pa at 23 ° C.

 [7] The pressure sensitive adhesive sheet according to any one of [1] to [6], wherein each of the two pressure sensitive adhesive layers is provided on both surfaces of the thermally expandable base material.

 [8] The pressure sensitive adhesive sheet according to any one of [1] to [7], in which the average particle diameter before expansion of the thermally expandable particles at 23 ° C is 3 to 100 µm.

 [9] The pressure sensitive adhesive sheet according to any one of [1] to [8], which uses a sealing resin and is used in a sealing step accompanied by heating.

 [10] A thermally expandable base material comprising a resin and thermally expandable particles having an expansion start temperature (t) of 120 to 250 ° C, which are non-tacky and satisfy the following requirements (1) to (2).

Requirement (1): The storage elastic modulus (Ek) 100 of the thermally expandable substrate is 100 × 10 ⁵ Pa or more at 100 ° C.

Requirement (2): The storage elastic modulus (E) (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles.

 [11] After the adhesive sheet according to any one of [1] to [9] is attached to the adherend, the adhesive sheet is peeled from the adherend by heat treatment at an expansion start temperature (t) or higher. , The use method of the adhesive sheet.

 [12] The method for using the pressure sensitive adhesive sheet according to the above [11], which uses a sealing resin and is used in a sealing step with heating.

When the adhesive sheet of the present invention is temporarily fixed, the sheet can be easily peeled off with a weak force during peeling while suppressing the settling of the target object during heating.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the adhesive sheet which shows an example of the structure of the adhesive sheet of this invention.
It is a cross-sectional schematic diagram of the double-sided adhesive sheet which shows an example of a structure of the adhesive sheet of this invention.
It is a cross-sectional schematic diagram which shows an example of FOWLP.

In this invention, an "active component" refers to the component except a dilution solvent among the components contained in the target composition.

In addition, a mass mean molecular weight (Mw) is a standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method, and is a value measured based on the method as described in an Example specifically.

In the present invention, for example, "(meth) acrylic acid" refers to both "acrylic acid" and "methacrylic acid", and similar terms are also the same.

In addition, about the preferable numerical range (for example, range of content etc.), the lower limit and upper limit described in steps can be combined independently, respectively. For example, from the description of "preferably 10 to 90, more preferably 30 to 60," "preferably the lower limit value 10" and "more preferable upper limit value 60" are combined to be "10 to 60". It may be.

[Configuration of PSA Sheet of the Present Invention]

The pressure-sensitive adhesive sheet of the present invention is not particularly limited as long as it includes a resin and thermally expandable particles, and has a pressure-sensitive adhesive layer containing a non-tacky heat-expandable base material and an adhesive resin.

1 and 2 are cross-sectional schematic diagrams of a pressure-sensitive adhesive sheet showing the configuration of the pressure-sensitive adhesive sheet of the present invention.

As an adhesive sheet of one form of this invention, the adhesive sheet 1a which has the adhesive layer 12 on the thermally expandable base material 11 shown to FIG. 1 (a) is mentioned.

In addition, the adhesive sheet of one embodiment of the present invention may be configured to further include a release material 13 on the adhesive surface of the adhesive layer 12, as in the adhesive sheet 1b shown in FIG. 1 (b).

As an adhesive sheet of another form of this invention, you may make it the structure which has two said adhesive layers, respectively on both surfaces of the said thermally expansible base material.

As an adhesive sheet of such a structure, both surfaces which have a structure which clamped the thermally expandable base material 11 as shown to FIG. 2 (a) to the 1st adhesive layer 121 and the 2nd adhesive layer 122, for example. The adhesive sheet 2a is mentioned.

Moreover, like the double-sided adhesive sheet 2b shown to FIG. 2 (b), it has further the peeling material 131 on the adhesive surface of the 1st adhesive layer 121, and on the adhesive surface of the 2nd adhesive layer 122 It is good also as a structure which has the peeling material 132 in the same.

In addition, in the double-sided adhesive sheet 2b shown to FIG. 2 (b), the peeling force at the time of peeling off the peeling material 131 from the 1st adhesive layer 121, and the peeling material 132 are the 2nd adhesive layer 122 When the peeling force at the time of peeling off from an adhesive is about the same, when pulling out both peeling materials to the outside, the adhesive layer may split and peel in accordance with two peeling materials, and may arise.

From the standpoint of suppressing such a phenomenon, it is preferable that the two release materials 131 and 132 use two types of release materials designed to have different peeling forces from the pressure-sensitive adhesive layers attached to each other.

As another adhesive sheet, in the double-sided adhesive sheet 2a shown to FIG. 2 (a), the peeling process was given to both adhesive surfaces of the 1st adhesive layer 121 and the 2nd adhesive layer 122 on both surfaces. The double-sided adhesive sheet which has a structure which rolled up what laminated | stacked the peeling material was laminated may be sufficient.

Here, in the adhesive sheet of one embodiment of the present invention, a constitution may be provided having another layer between the thermally expandable substrate and the pressure-sensitive adhesive layer.

However, from the viewpoint of the adhesive sheet which can be easily peeled off by a weak force, as in the adhesive sheets 1a and 1b shown in FIG. 1 and the double-sided adhesive sheets 2a and 2b shown in FIG. 11) and the pressure-sensitive adhesive layer 12 is preferably laminated directly.

[Thermally expandable base material]

The heat-expandable base material of the pressure-sensitive adhesive sheet of the present invention includes resin and heat-expandable particles having an expansion start temperature (t) of 120 to 250 ° C, and satisfy the following requirements (1) to (2) as non-tacky base materials. .

Requirement (1): The storage elastic modulus (Ek) 100 of the thermally expandable substrate is 100 × 10 ⁵ Pa or more at 100 ° C.

Requirement (2): The storage elastic modulus (E) (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles.

In addition, in this specification, the storage elastic modulus (E ') of a thermally expansible base material at predetermined temperature means the value measured according to the method as described in an Example.

For example, in the sealing step of the manufacturing process of FOWLP, the sealing resin of the state which has a fluidity by heating to around 100 degreeC is filled on a semiconductor chip, or the resin sheet for sealing is laminated | stacked on a semiconductor chip, and is heated and laminated. According to the method, it is common to encapsulate a semiconductor chip.

That is, the said requirement (1) assumes the temperature environment in the sealing process of the manufacturing process of FOWLP as 100 degreeC, and prescribes the storage elastic modulus (E ') of a thermally expansible base material in the temperature environment in a sealing process.

Generally, since the thermally expansible adhesive layer like the adhesive sheet of patent document 1 contains adhesive resin, there exists a tendency for the grade of the fall of storage elastic modulus (E ') to become very large with an increase of temperature.

Here, when the extent of the fall of the storage elastic modulus (E ') of a thermally expansible adhesive layer becomes very large, the thermally expansible particle and adhesive resin contained in a thermally expansible adhesive layer will flow easily, and the adhesive surface of a thermally expansible adhesive layer will therefore flow It becomes easy to deform.

As a result, when sealing is carried out on objects, such as a semiconductor chip, for example, by heating around 100 degreeC and flowing the sealing resin which has fluidity, an adhesive sheet becomes flexible according to the weight and heating of the said sealing resin. By doing so, the object tends to settle to the adhesive sheet side. The sedimentation of the object may be a cause of the positional shift of the object, the occurrence of the deviation of the distance between the objects, and the unevenness on the surface of the side where the object is placed after sealing, resulting in inferior flatness. In addition, this problem may similarly arise in the sealing method by the laminate using the resin film for sealing.

Moreover, also in the adhesive sheet which provided the new adhesive layer on the surface of said thermally expansible adhesive layer, the deformation | transformation of the adhesive surface of an adhesive layer by the flow of thermally expansible particle and adhesive resin in a thermally expansible adhesive layer as mentioned above is carried out. It is easy to occur, and the above-mentioned problem may arise.

In response to this problem, the pressure-sensitive adhesive sheet of the present invention contains a resin and thermally expandable particles, and as defined in the above requirement (1), the storage modulus (E ＇) 100 at 100 ° C. is 2.0 × 10 ⁵ Pa. The above-mentioned problem is aimed at by using the thermally expansible base material adjusted above.

Having a thermally expandable base material satisfying the requirement (1), the pressure-sensitive adhesive provided on the thermally expandable base material can be appropriately suppressed even under a temperature environment in a sealing step such as a manufacturing process of a FOWLP. The adhesive surface of the layer becomes difficult to deform.

As a result, the object settles to the adhesive sheet side by the weight of the encapsulation resin laminated on the object such as a semiconductor chip, or the pressure accompanying the laminate using the resin sheet for encapsulation. The occurrence of misalignment can be suppressed.

On the other hand, when the thermally expansible base material whose storage elastic modulus (E ') 100 is less than 2.0 * 10 <^5> Pa is used, the fluidity | liquidity of the thermally expansible particle | grains contained in a thermally expansible base material fully in the temperature environment of 100 degreeC which assumed the sealing process is sufficient. It is not suppressed, and the deformation | transformation of the adhesive surface of the adhesive layer provided on the thermally expansible base material tends to occur.

As a result, for example, when the adhesive sheet which has the said thermally expansible base material is used for the sealing process of manufacture of FOWLP, a semiconductor chip is an adhesive sheet according to the weight of sealing resin or the pressure accompanying a laminate using the resin sheet for sealing. It is settled to the pressure-sensitive adhesive layer side, and unevenness can be seen on the surface of the semiconductor chip side after encapsulation.

Although the storage elastic modulus (E ') 100 prescribed | regulated by the requirement (1) of the thermally expansible base material used by one Embodiment of this invention is 2.0 * 10 <^5> Pa or more, from said viewpoint, Preferably it is 4.0 * 10 <^5> Pa. Above, More preferably, it is 6.0 * 10 <^5> Pa or more, More preferably, it is 8.0 * 10 <^5> Pa or more, More preferably, it is 1.0 * 10 <^6> Pa or more.

In the encapsulation step, the storage elastic modulus (E) 100 defined in the requirement (1) of the thermally expandable substrate is preferably 1.0 × from the viewpoint of effectively suppressing the positional shift of the encapsulation object such as a semiconductor chip. 10 ¹² Pa or less, More preferably, it is 1.0 * 10 <^11> Pa or less, More preferably, it is 1.0 * 10 <^10> Pa or less, More preferably, it is 1.0 * 10 <^9> Pa or less.

On the other hand, the said requirement (2) defines the storage elastic modulus (E ') of a thermally expansible base material at the time of peeling of an adhesive sheet.

When peeling the adhesive sheet of the present invention from the adherend, the thermally expandable particles in the thermally expandable substrate are expanded by heating to a temperature at or above the expansion start temperature t of the thermally expandable particles, and irregularities are formed on the surface of the thermally expandable substrate. The pressure-sensitive adhesive layer laminated on the unevenness is also pushed up, and unevenness is formed on the pressure-sensitive adhesive surface.

The contact area between the adherend (semiconductor chip and cured encapsulating resin) and the adhesion surface is reduced by forming irregularities on the adhesive surface of the adhesive layer, and a space is formed between the adherend and the adhesion surface, thereby adhering from the adherend. The sheet can be easily peeled off with a weak force.

By the way, in order to improve the peelability of an adhesive sheet, when heating to the temperature beyond expansion start temperature t, it is necessary to make it easy to form an unevenness | corrugation on the adhesive surface of an adhesive layer. For that purpose, it is necessary to adjust the thermally expandable particles contained in the thermally expandable substrate so as to easily expand.

In the above requirement (2), the storage modulus (E) (t) of the thermally expandable substrate is defined at the expansion start temperature (t) of the thermally expandable particles. It can also be said to be an index which shows the rigidity of a base material.

That is, the according to the studies of the inventors, when the heat-expandable base material at the expansion initiating temperature of heat-expandable particles (t) the storage elastic modulus (E ') (t) exceeds 1.0 × 10 ⁷ Pa, the expansion starting temperature (t) or more Even when heated to a temperature and the thermally expandable particles attempt to expand, it was found that the expansion was suppressed so that the thermally expandable particles did not become sufficiently large and that the uneven formation of the adhesive surface of the pressure-sensitive adhesive layer laminated on the surface of the thermally expandable substrate was insufficient. .

The storage modulus (E) (t) specified in the requirement (2) of the heat-expandable base material used in one embodiment of the present invention is preferably 9.0 × 10 ⁶ Pa or less, more preferably 8.0 × from the above viewpoint. 10 ⁶ Pa or less, More preferably, it is 6.0x10 ⁶ Pa or less, More preferably, it is 4.0x10 ⁶ Pa or less.

Furthermore, from the viewpoint of suppressing the flow of the expanded thermally expandable particles, improving the shape retention of the irregularities formed on the adhesive surface of the pressure-sensitive adhesive layer, and further improving the peelability, the requirements described in the requirement (2) of the thermally expandable base material are given. The storage modulus (E ′) t is preferably 1.0 × 10 ³ Pa or more, more preferably 1.0 × 10 ⁴ Pa or more, and still more preferably 1.0 × 10 ⁵ Pa or more.

Moreover, it is preferable that the thermally expansible base material which the adhesive sheet of one embodiment of this invention has further satisfy | fills the following requirement (3).

Requirements (3): The storage elastic modulus (E ′) 23 of the thermally expandable substrate at 23 ° C. is 1.0 × 10 ⁶ Pa or more.

By using the thermally expansible base material which satisfy | fills the said requirement (3), position shift at the time of sticking objects, such as a semiconductor chip, can be prevented. Moreover, when sticking an object, excessive sedimentation to an adhesive layer can also be prevented.

For example, the semiconductor chip is normally placed so that its circuit surface is covered with the adhesive surface of the pressure-sensitive adhesive layer. For example, a well-known apparatus such as a flip chip bonder or a die bonder may be used for placing the semiconductor chip.

Here, when placing a semiconductor chip on the adhesive layer of an adhesive sheet using a flip chip bonder or a die bonder, the force which pushes a semiconductor chip in the thickness direction of an adhesive sheet is applied, and a semiconductor chip is a thickness direction of an adhesive layer. There is a possibility of excessive sedimentation on the side.

In addition, when placing a semiconductor chip on an adhesive sheet using a flip chip bonder or a die bonder, the force which moves a semiconductor chip to the horizontal direction of an adhesive sheet is also applied, and a semiconductor chip shifts in the horizontal direction of an adhesive layer. There is also concern.

However, such a problem can also be solved by making it the thermally expandable base material satisfying the above requirement (3).

In view of the above, the storage modulus (E) 23 of the thermally expandable base material specified in the requirement (3) is preferably 5.0 × 10 ⁶ to 5.0 × 10 ¹² Pa, more preferably 1.0 × 10 ⁷ to 1.0 × 10 ¹² Pa, more preferably 5.0 × 10 ⁷ to 1.0 × 10 ¹¹ Pa, still more preferably 1.0 × 10 ⁸ to 1.0 × 10 ¹⁰ Pa.

In one aspect of the present invention, the thickness of the thermally expandable substrate at 23 ° C is preferably 10 to 1000 µm, more preferably 20 to 500 µm, still more preferably 25 to 400 µm, even more preferably 30 to 300 µm.

In addition, in this specification, the thickness of a thermally expansible base material means the value measured according to the method as described in an Example. In addition, the thickness of the said thermally expansible base material is a value before expansion of thermally expansible particle | grains.

The heat-expandable base material which the adhesive sheet of one embodiment of the present invention has is a non-adhesive base material.

In the present invention, whether the non-tacky substrate is a non-tacky substrate is determined based on the surface of the target substrate when the probe tack value measured in accordance with JIS Z0237: 1991 is less than 50 mN / 5 mmφ. I judge it.

Here, the probe tack value on the surface of the thermally expandable base material used in one embodiment of the present invention is usually less than 50 mN / 5 mmφ, preferably less than 30 mN / 5 mmφ, more preferably less than 10 mN / 5 mmφ, Preferably it is less than 5 mN / 5 mmφ.

In addition, in this specification, the specific measuring method of the probe tack value on the surface of a thermally expansible base material follows the method as described in an Example.

Although the heat-expandable base material which the adhesive sheet of one embodiment of this invention contains resin and heat-expandable particle | grains, you may contain an additive for a base material as needed in the range which does not impair the effect of this invention.

In addition, the thermally expandable substrate may be formed of a resin composition (y) containing a resin and thermally expandable particles.

Hereinafter, each component contained in the resin composition (y) which is a formation material of a thermally expandable base material is demonstrated.

<Resin>

As resin contained in resin composition (y), what is necessary is just a polymer which can form the thermally expandable base material which satisfy | fills the said requirements (1) and (2).

Moreover, as resin contained in resin composition (y), non-adhesive resin may be sufficient and adhesive resin may be sufficient.

That is, even if the resin contained in the resin composition (y) is an adhesive resin, in the process of forming the thermally expandable base material with the resin composition (y), the resin obtained by polymerizing the adhesive resin with the polymerizable compound is non-tacky resin, The heat-expandable base material containing the resin may be non-tacky.

As mass average molecular weight (Mw) of the said resin contained in resin composition (y), Preferably it is 1,000-1 million, More preferably, it is 1000-700,000, More preferably, it is 1000-500,000.

In addition, when the said resin is a copolymer which has a 2 or more types of structural unit, the form of the said copolymer is not specifically limited, Any of a block copolymer, a random copolymer, and a graft copolymer may be sufficient.

As for content of the said resin, with respect to whole quantity (100 mass%) of the active ingredient of resin composition (y), Preferably it is 50-99 mass%, More preferably, it is 60-95 mass%, More preferably, it is 65-90 It is mass%, More preferably, it is 70-85 mass%.

Moreover, from the viewpoint of forming a thermally expandable base material satisfying the above requirements (1) and (2), the resin contained in the resin composition (y) includes at least one member selected from acrylic urethane resins and olefin resins. It is preferable.

Moreover, as said acrylic urethane type resin, the following resin (U1) is preferable.

Acrylic urethane resin (U1) formed by superposing | polymerizing the vinyl compound containing a urethane prepolymer (UP) and (meth) acrylic acid ester.

(Acrylic urethane resin (U1))

As a urethane prepolymer (UP) used as the main chain of acryl urethane-type resin (U1), the reaction material of a polyol and polyhydric isocyanate is mentioned.

Moreover, it is preferable that urethane prepolymer (UP) is obtained by performing the chain extension reaction using a chain extender further.

As a polyol used as a raw material of a urethane prepolymer (UP), an alkylene type polyol, an ether type polyol, ester type polyol, ester amide type polyol, ester ether polyol, carbonate type polyol, etc. are mentioned, for example.

These polyols may be used independently and may use 2 or more types together.

As a polyol used by one form of this invention, diol is preferable, ester type diol, alkylene type diol, and carbonate type diol are more preferable, and ester type diol and carbonate type diol are more preferable.

As ester type diol, For example, Alkanediol, such as 1, 3- propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 1, 6- hexanediol; Alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol; One or two or more selected from diols such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, diphenylmethane-4 and 4'-dicar Acid, succinic acid, adipic acid, azelaic acid, sebacic acid, het acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1, 3-dicarboxylic acid, cyclohexane-1, 4-dicarboxylic acid, hexa 1 type, or 2 or more types of condensers chosen from dicarboxylic acids, such as hydrophthalic acid, hexahydroisophthalic acid, hexahydro terephthalic acid, methyl hexahydrophthalic acid, and these anhydrides, are mentioned.

Specifically, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, Polybutylene hexamethylene adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azerate diol, polyethylene sebacate diol, poly Butylene azelate diol, polybutylene sebacate diol, poly neopentyl terephthalate diol and the like.

As alkylene type diol, For example, Alkanediol, such as 1, 3- propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol, 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; Etc. can be mentioned.

Examples of the carbonate type diol include 1, 4-tetramethylene carbonate diol, 1, 5-pentamethylene carbonate diol, 1, 6-hexamethylene carbonate diol, 1, 2-propylene carbonate diol, 1, 3-propylene carbonate Diol, 2, 2-dimethyl propylene carbonate diol, 1, 7-hepta methylene carbonate diol, 1, 8-octamethylene carbonate diol, 1, 4-cyclohexane carbonate diol, etc. are mentioned.

As polyhydric isocyanate used as a raw material of a urethane prepolymer (UP), aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, etc. are mentioned.

Such polyhydric isocyanate may be used independently and may use 2 or more types together.

Moreover, such polyvalent isocyanate may be a trimetholpropane adduct-type modified body, a biuret-type modified body reacted with water, and an isocyanurate-type modified body containing an isocyanurate ring.

Among these, as polyhydric isocyanate used by one form of this invention, diisocyanate is preferable and 4,4'- diphenylmethane diisocyanate (MDI), 2, 4-tolylene diisocyanate (2, 4-TDI) More preferably, 1 or more types chosen from 2, 6-tolylene diisocyanate (2, 6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate.

As alicyclic diisocyanate, it is 3-isocyanate methyl-3, 5, 5-trimethyl cyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1, 3- cyclopentane diisocyanate, 1, 3-cyclohexane di, for example. Isocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, etc. are mentioned, but isophorone diisocyanate (IPDI) is preferable.

In one embodiment of the present invention, as the urethane prepolymer (UP) serving as the main chain of the acrylic urethane resin (U1), a linear urethane prepolymer having a reaction product of diol and diisocyanate and having an ethylenically unsaturated group at the end thereof is preferable.

As a method of introducing an ethylenically unsaturated group into the sock end of the said linear urethane prepolymer, the method of making NCO group and hydroxyalkyl (meth) acrylate of the terminal of the linear urethane prepolymer which react by diol and a diisocyanate compound react is mentioned Can be.

As hydroxyalkyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy, for example Hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.

As a vinyl compound used as the side chain of acryl urethane type resin (U1), it contains at least (meth) acrylic acid ester.

As (meth) acrylic acid ester, 1 or more types chosen from alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate are preferable, and it uses together alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate. It is more preferable.

When using an alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate together, as a compounding ratio of hydroxyalkyl (meth) acrylate with respect to 100 mass parts of alkyl (meth) acrylates, Preferably it is 0.1-100. A mass part, More preferably, it is 0.5-30 mass parts, More preferably, it is 1.0-20 mass parts, More preferably, it is 1.5-10 mass parts.

As carbon number of the alkyl group which the said alkyl (meth) acrylate has, Preferably it is 1-24, More preferably, it is 1-12, More preferably, it is 1-8, More preferably, it is 1-3.

Moreover, as hydroxyalkyl (meth) acrylate, the same thing as hydroxyalkyl (meth) acrylate used in order to introduce an ethylenically unsaturated group in the distal end of the above-mentioned linear urethane prepolymer is mentioned.

As vinyl compounds other than (meth) acrylic acid ester, For example, aromatic hydrocarbon vinyl compounds, such as styrene, (alpha) -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 meta (acrylamide); Etc. can be mentioned.

These may be used independently and may use 2 or more types together.

As content of the (meth) acrylic acid ester in a vinyl compound, Preferably it is 40-100 mass%, More preferably, it is 65-100 mass%, More preferably, 80-100 with respect to whole quantity (100 mass%) of the said vinyl compound. 100 mass%, More preferably, it is 90-100 mass%.

As total content of the alkyl (meth) acrylate and hydroxyalkyl (meth) acrylate in a vinyl compound, Preferably it is 40-100 mass% with respect to whole quantity (100 mass%) of the said vinyl compound, More preferably, 65 ~ 100 mass%, More preferably, it is 80-100 mass%, More preferably, it is 90-100 mass%.

Acrylic urethane resin (U1) used by one form of this invention is obtained by mixing a urethane prepolymer (UP) and the vinyl compound containing a (meth) acrylic acid ester, and polymerizing both.

In the said polymerization, it is preferable to add and add a radical initiator further.

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

(Olefin resin)

As an olefin resin suitable as resin contained in a resin composition (y), it is a polymer which has at least a structural unit derived from an olefin monomer.

As said olefin monomer, a C2-C8 alpha olefin is preferable and ethylene, propylene, butylene, isobutylene, 1-hexene etc. are mentioned specifically ,.

Among these, ethylene and propylene are preferable.

Specific concrete olefin resins include, for example, ultra low density polyethylene (VLDPE, density: 880 kg / m 3 or more and less than 910 kg / m 3), low density polyethylene (LDPE, density: 910 kg / m 3 or more and less than 915 kg / m 3), medium density polyethylene Polyethylene resins such as (MDPE, density: 915 kg / m 3 or more and less than 942 kg / m 3), high density polyethylene (HDPE, density: 942 kg / m 3 or more), and linear low density polyethylene; Polypropylene resin (PP); Polybutene resin (PB); Ethylene-propylene copolymers; Olefin elastomers (TPO); Poly (4-methyl-1-pentene) (PMP); Ethylene-vinyl acetate copolymers (EVA); Ethylene-vinyl alcohol copolymers (EVOH); Olefin terpolymers such as ethylene-propylene- (5-ethylidene-2-norbornene); Etc. can be mentioned.

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

For example, the modified polymer formed by graft polymerizing unsaturated carboxylic acid or its anhydride to the above-mentioned unmodified olefin resin is mentioned as acid-modified olefin resin formed by acid-modification with respect to olefin resin. .

As said unsaturated carboxylic acid or its anhydride, for example, maleic acid, fumaric acid, itaconic acid, citraconic acid, glutamic acid, tetrahydrophthalic acid, aconic acid, (meth) acrylic acid, maleic anhydride, itaconic anhydride , Glutaconic anhydride, citraconic anhydride, aconic acid anhydride, norbornene dicarboxylic acid anhydride, tetrahydrophthalic anhydride and the like.

Moreover, unsaturated carboxylic acid or its anhydride may be used independently and may use 2 or more types together.

Examples of the acryl-modified olefin resin formed by acryl modification of the olefin resin include modified polymers obtained by graft polymerization of alkyl (meth) acrylate as a side chain to the above-mentioned unmodified olefin resin which is a main chain.

As carbon number of the alkyl group which said alkyl (meth) acrylate has, Preferably it is 1-20, More preferably, it is 1-16, More preferably, it is 1-12.

As said alkyl (meth) acrylate, the same thing as the compound selectable as a monomer (a1 ') mentioned later is mentioned, for example.

As a hydroxyl-modified olefin resin formed by hydroxyl-modifying about an olefin resin, the modified polymer formed by graft-polymerizing a hydroxyl-containing compound to the above-mentioned unmodified olefin resin which is a main chain is mentioned.

As said hydroxyl group containing compound, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl ( Hydroxyalkyl (meth) acrylates such as meta) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; Unsaturated alcohol, such as vinyl alcohol and allyl alcohol, etc. are mentioned.

(Resins other than acrylic urethane resins and olefin resins)

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

As such resin, For example, Vinyl-type resin, such as polyvinyl chloride vinyl, polyvinylidene chloride, and polyvinyl alcohol; Polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polystyrene; Acrylonitrile-butadiene-styrene copolymers; Cellulose triacetate; Polycarbonate; Polyurethane which does not correspond to acrylic urethane resin; Polysulfones; Polyether ether ketone; Polyethersulfones; Polyphenylene sulfide; Polyimide resins such as polyetherimide and polyimide; Polyamide-based resins; Acrylic resins; Fluorine resins and the like.

In view of forming a thermally expandable base material that satisfies the requirements (1) and (2), however, it is preferable that the content ratio of resins other than the acrylic urethane resin and the olefin resin in the resin composition (y) is small.

As content rate of resin other than acrylic urethane type resin and olefin resin, Preferably it is less than 30 mass parts, More preferably, it is less than 20 mass parts, with respect to 100 mass parts of total amounts of resin contained in a resin composition (y). Preferably it is less than 10 mass parts, More preferably, it is less than 5 mass parts, More preferably, it is less than 1 mass part.

<Thermally expandable particle>

The thermally expandable particles used in the present invention may be particles having an expansion start temperature t adjusted to 120 to 250 ° C, and are appropriately selected according to the use.

In addition, in this specification, the expansion start temperature t of thermally expansible particle | grains means the value measured based on the following method.

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

0.5 mg of thermally expandable particles to be measured are added to an aluminum cup having a diameter of 6.0 mm (inner diameter 5.65 mm) and a depth of 4.8 mm, and a sample having an aluminum lid (5.6 mm in diameter and 0.1 mm in thickness) is prepared thereon. do.

Using a dynamic viscoelasticity measuring device, the height of the sample is measured in a state where a force of 0.01 N is applied from the upper portion of the aluminum lid with a pressurizer. Then, in a state where a force of 0.01 N is applied with a pressurizer, heating is performed at a heating rate of 10 ° C / min from 20 ° C to 300 ° C, the displacement amount in the vertical direction of the pressurizer is measured, and the start of expansion of the displacement start temperature in the forward direction is started. Let it be temperature t.

The thermally expandable particles are preferably microencapsulated blowing agents composed of an outer shell made of a thermoplastic resin and an inclusion component contained in the outer shell and vaporized when heated to a predetermined temperature.

As the thermoplastic resin constituting the outer shell of the microencapsulated blowing agent, for example, vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride And polysulfones.

As the nested components contained in the outer shell, for example, propane, butane, pentane, hexane, heptane, octane, nonane, decane, isobutane, isopentane, isohexane, isoheptane, isooctane, isononane, isodecane and cyclopropane , Cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isododecane, cyclotridecane, hexyl cyclohexane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octa Decane, nonadecane, isotridecane, 4-methyl dodecane, isotetradecane, isopentadecane, isohexadecane, 2, 2, 4, 4, 6, 8, 8-heptamethyl nonane, isoheptadecane, iso Octadecane, isononadecane, 2, 6, 10, 14-tetramethyl pentadecane, cyclotridecane, heptyl cyclohexane, n-octyl cyclohexane, cyclopentadecane, nonyl cyclohexane, decylcyclohexane, pentadecyl cyclo Hexane, hexadecyl cyclohexane, heptadecyl cyclohexane And octadecyl cyclohexane.

These inclusion components may be used alone or in combination of two or more thereof.

The expansion start temperature t of the thermally expandable particles can be adjusted by appropriately selecting the kind of inclusion component.

The average particle diameter before expansion at 23 ° C. of the thermally expandable particles used in one embodiment of the present invention is preferably 3 to 100 μm, more preferably 4 to 70 μm, still more preferably 6 to 60 μm, even more preferably. 10 to 50 μm.

Also it means the average grain diameter before expansion of the heat expandable particles, and the volume median particle size (D _50), and a laser diffraction particle size distribution analyzer (for example, Malvern Corporation, product name "MASTERSIZER 3000") prior to the expansion measured using a In particle distribution of thermally expansible particle | grains, it means the particle diameter whose cumulative volume frequency calculated by the one where the particle diameter of thermally expansible particle before expansion is smaller corresponds to 50%.

As the 90% particle diameter (D ₉₀₎ prior to expansion in 23 ℃, the heat-expandable particles to be used in one aspect of the present invention, preferably from 10 ~ 150μm, more preferably 20 ~ 100μm, and more preferably 25 ~ 90μm, Even more preferably, it is 30-80 micrometers.

The 90% particle size (D ₉₀ ) before expansion of the thermally expandable particles refers to the thermally expandable particles before expansion, measured using a laser diffraction particle size distribution measuring device (for example, Malzern, product name "MASTERSIZER 3000"). In particle distribution, it means the particle diameter whose cumulative volume frequency calculated by the particle diameter of thermally expansible particle before expansion is smaller than 90%.

The volume maximum expansion ratio when it heats to the temperature beyond the expansion start temperature (t) of the thermally expandable particles used in one embodiment of the present invention is preferably 1.5 to 100 times, more preferably 2 to 80 times, even more preferably Is 2.5 to 60 times, even more preferably 3 to 40 times.

Content of thermally expansible particle | grains becomes like this. Preferably it is 1-40 mass%, More preferably, it is 5-35 mass%, More preferably, 10-10 with respect to whole quantity (100 mass%) of the active ingredient of resin composition (y). 30 mass%, More preferably, it is 15-25 mass%.

<Additive for base material>

The resin composition (y) used by one Embodiment of this invention may contain the additive for base materials contained in the base material which a general adhesive sheet has in the range which does not impair the effect of this invention.

As such a base material additive, a ultraviolet absorber, a light stabilizer, antioxidant, an antistatic agent, a slip agent, an anti blocking agent, a coloring agent, etc. are mentioned, for example.

In addition, these additives for base materials may be used independently, respectively and may use 2 or more types together.

When it contains such a base material additive, content of each base material additive becomes like this. Preferably it is 0.0001-20 mass parts, More preferably, it is 0.001--10 mass parts with respect to 100 mass parts of said resins in a resin composition (y). to be.

<Solvent-free resin composition (y1)>

As the resin composition (y) used in one embodiment of the present invention, from the viewpoint of forming a thermally expandable base material that satisfies the requirements (1) and (2), the mass average molecular weight (Mw) has an ethylenically unsaturated group having 50000 or less. A non-solvent type resin composition (y1) which mix | blends an oligomer, an energy-beam polymerizable monomer, and the above-mentioned thermally expandable particle | grains, and does not mix | blend a solvent is mentioned.

In a non-solvent type resin composition (y1), although a solvent is not mix | blended, an energy-beam polymerizable monomer contributes to the improvement of the plasticity of the said oligomer.

It is easy to form the thermally expansible base material which satisfy | fills the said requirements (1) and (2) by irradiating an energy ray with respect to the coating film formed from the non-solvent type resin composition (y1).

Moreover, the kind, shape, and compounding quantity (content) of the thermally expansible particle | grains mix | blended with a non-solvent type resin composition (y1) are as having mentioned above.

Although the mass average molecular weight (Mw) of the said oligomer contained in a non-solvent type resin composition (y1) is 50000 or less, Preferably it is 1000-50000, More preferably, 2000-40000, More preferably, 3000-35000, Even more preferable It is 4000 to 30000.

In addition, as said oligomer, what is necessary is just to have an ethylenically unsaturated group whose mass mean molecular weight is 50000 or less among resin contained in the resin composition (y) mentioned above, The urethane prepolymer (UP) mentioned above is preferable.

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

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

As an energy-beam polymerizable monomer, for example, isobonyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, and cyclo Alicyclic polymerizable compounds such as hexyl (meth) acrylate, adamantane (meth) acrylate, and tricyclodecane acrylate; Aromatic polymerizable compounds such as phenyl hydroxypropyl acrylate, benzyl acrylate and phenol ethylene oxide modified acrylate; Heterocyclic polymeric compounds, such as tetrahydrofurfuryl (meth) acrylate, morpholine acrylate, N-vinylpyrrolidone, and N-vinyl caprolactam, etc. are mentioned.

These energy ray polymerizable monomers may be used independently and may use 2 or more types together.

The content ratio [oligomer / energy ray polymerizable monomer] of the oligomer and the energy ray polymerizable monomer in the non-solvent type resin composition (y1) is, in mass ratio, preferably 20/80 to 90/10, more preferably Is 30/70 to 85/15, more preferably 35/65 to 80/20.

In one embodiment of the present invention, the solvent-free resin composition (y1) is preferably formed by further mixing a photopolymerization initiator.

By containing a photoinitiator, hardening reaction can fully advance also by irradiation of a comparatively low energy energy ray.

As a photoinitiator, it is 1-hydroxy cyclohexyl phenyl- ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethyl thiuram monosulfide, azo, for example. Bisisobutyronitrile, dibenzyl, diacetyl, 8-chloro anthraquinone, etc. are mentioned.

These photoinitiators may be used independently and may use 2 or more types together.

The compounding quantity of a photoinitiator becomes like this. Preferably it is 0.01-5 mass parts, More preferably, 0.01-4 mass parts, More preferably, 0.02-3 with respect to whole quantity (100 mass parts) of the said oligomer and an energy-beam polymerizable monomer. It is a mass part.

[Adhesive layer]

The adhesive layer which the adhesive sheet of one Embodiment of this invention should just contain adhesive resin, and may contain additives for adhesives, such as a crosslinking agent, a tackifier, a polymeric compound, and a polymerization initiator, as needed.

Moreover, it is preferable that the adhesive layer which the adhesive sheet of one form of this invention has is a non-thermally expansible adhesive layer from a viewpoint of preventing the object, such as a semiconductor chip mounted by heating in a sealing process, from settling in an adhesive layer.

In one embodiment of the present invention, the adhesive force of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer on which an object such as a semiconductor chip is placed at 23 ° C. before expansion of the thermally expandable particles is preferably 0.1 to 10.0 N / 25 mm, more preferably 0.2 To 8.0 N / 25 mm, more preferably 0.4 to 6.0 N / 25 mm, even more preferably 0.5 to 4.0 N / 25 mm.

When the said adhesive force is 0.1N / 25mm or more, to-be-adhered bodies, such as a semiconductor chip, can be fully fixed to such an extent that position shift can be prevented in the next process, such as a sealing process.

On the other hand, when the said adhesive force is 10.0 N / 25 mm or less, it can peel easily with a weak force by heating to the temperature of expansion start temperature t or more at the time of peeling.

In addition, said adhesive force means the value measured according to the method as described in an Example.

In the pressure-sensitive adhesive sheet of one embodiment of the present invention, as the storage shear modulus (GV) 23 of the pressure-sensitive adhesive layer on which objects such as semiconductor chips are placed at 23 ° C, preferably 1.0 × 10 ⁴ to 1.0 × 10 ⁸ Pa, More preferably, it is 5.0 * 10 <^4> -5.0 * 10 <^7> Pa, More preferably, it is 1.0 * 10 <^5> -1.0 * 10 <^7> Pa.

When the storage shear modulus (G ＇) 23 of the said adhesive layer is 1.0 * 10 <^4> Pa or more, position shift at the time of sticking objects, such as a semiconductor chip, can be prevented, and also to the adhesive layer at this time Excessive sedimentation can be prevented.

On the other hand, when the storage shear modulus (G ') 23 of the pressure-sensitive adhesive layer is 1.0 × 10 ⁸ Pa or less, it is easy to deform by heating to a temperature equal to or more than the expansion start temperature t at the time of peeling, and thermal expansion in the thermally expandable substrate Unevenness easily forms on the surface of the pressure-sensitive adhesive layer due to expansion of the sexual particles, and as a result, it can be easily peeled off with a weak force.

In addition, in this specification, the storage shear modulus (G ') 23 of an adhesive layer means the value measured according to the method as described in an Example.

In addition, in the case of an adhesive sheet having a plurality of pressure sensitive adhesive layers as in the double-sided pressure sensitive adhesive sheets 2a and 2b shown in FIG. 2, the storage shear modulus (G ＇) of the pressure sensitive adhesive layer on which an object such as a semiconductor chip is placed among the plurality of pressure sensitive adhesive layers (23) is preferably in the above range.

On the other hand, in order to fix an adhesive sheet, as storage storage elastic modulus (G ') 23 of the adhesive layer of the side stuck to a support body etc. at 23 degreeC, from a viewpoint of improving adhesiveness with a support body etc., Preferably it is 1.0x10. ⁴ to 1.0 × 10 ⁸ Pa, more preferably 3.0 × 10 ⁴ to 5.0 × 10 ⁷ Pa, still more preferably 5.0 × 10 ⁴ to 1.0 × 10 ⁷ Pa.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of one embodiment of the present invention is such that the unevenness is formed on the surface of the pressure-sensitive adhesive layer formed by the viewpoint of expressing excellent adhesive force and the expansion of thermally expandable particles in the heat-expandable base material by heat treatment. From the point of view of ease, it is preferably 1 to 60 µm, more preferably 2 to 50 µm, still more preferably 3 to 40 µm, even more preferably 5 to 30 µm.

In the pressure-sensitive adhesive sheet of one embodiment of the present invention, the ratio of the thickness of the thermally expandable base material to the thickness of the pressure-sensitive adhesive layer (heat-expandable base material / adhesive layer) at 23 ° C. in the sealing step such as a manufacturing process of FOWLP, on the object side after sealing. From the viewpoint of leveling the surface and preventing misalignment of the object, it 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, At the time, it is preferably 1000 or less, more preferably 200 or less, still more preferably 60 or less, and even more preferably 30 or less from the viewpoint of the adhesive sheet which can be easily peeled off with a weak force.

In addition, in this specification, when it is an adhesive sheet which has several adhesive layers like double-sided adhesive sheets 2a and 2b shown in FIG. 2, said "thickness of an adhesive layer" means the thickness of each adhesive layer. do. That is, it is preferable that thickness and the said ratio [thermally expansible base material / adhesive layer] are in the said range about each adhesive layer.

In addition, the thickness of an adhesive layer means the value measured according to the method as described in an Example.

The adhesive layer which the adhesive sheet of one form of this invention has can be formed from the adhesive composition containing adhesive resin.

In addition, like the double-sided adhesive sheets 2a and 2b shown in FIG. 2, in the adhesive sheet which has several adhesive layers, each adhesive layer may be formed from the same adhesive composition, and may be formed from different adhesive compositions.

Hereinafter, each component contained in the adhesive composition which is a formation material of an adhesive layer is demonstrated.

<Adhesive resin>

As adhesive resin used by 1 form of this invention, it is good if it has adhesiveness by said resin alone, and a mass mean molecular weight (Mw) is 10,000 or more polymer.

As mass average molecular weight (Mw) of adhesive resin used by 1 aspect of this invention, from a viewpoint of the improvement of adhesive force, Preferably it is 10,000-2 million, More preferably, it is 20,000-1,500,000, More preferably, it is 3 Only 1 million.

As specific adhesive resin, rubber resin, such as acrylic resin, urethane resin, and polyisobutylene resin, polyester resin, olefin resin, silicone resin, polyvinyl ether resin, etc. are mentioned, for example.

Such adhesive resin may be used independently and may use 2 or more types together.

In addition, when such adhesive resin is a copolymer which has a 2 or more types of structural unit, the form of the said copolymer is not specifically limited, Any of a block copolymer, a random copolymer, and a graft copolymer may be sufficient.

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

As said polymerizable functional group, a (meth) acryloyl group, a vinyl group, etc. are mentioned.

Moreover, although an ultraviolet ray and an electron beam are mentioned as an energy ray, an ultraviolet ray is preferable.

As for content of adhesive resin, with respect to whole quantity (100 mass%) of the active ingredient of an adhesive composition, Preferably it is 30-99.99 mass%, More preferably, it is 40-99.95 mass%, More preferably, 50-99.90 mass%, Even more preferably, it is 55-99.80 mass%, More preferably, it is 60-99.50 mass%.

In addition, in the following description of this specification, "content of each component with respect to the whole quantity of the active ingredient of an adhesive composition" is synonymous with "content of each component in the adhesive layer formed from the said adhesive composition."

In one embodiment of the present invention, the adhesive resin is acryl-based in view of expressing excellent adhesive force and from the viewpoint of easily forming irregularities on the surface of the pressure-sensitive adhesive layer formed by the expansion of the thermally expandable particles in the thermally expandable substrate by heat treatment. It is preferable to include resin.

As content rate of acrylic resin in adhesive resin, Preferably it is 30-100 mass%, More preferably, 50-100 mass%, More preferably, with respect to whole quantity (100 mass%) of adhesive resin contained in an adhesive composition. 70-100 mass%, More preferably, it is 85-100 mass%.

(Acrylic resin)

In one embodiment of the present invention, as the acrylic resin which can be used as the adhesive resin, for example, a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group or a cyclic structure can be used. The polymer etc. which contain the structural unit derived from a (meth) acrylate are mentioned.

As mass average molecular weight (Mw) of acrylic resin, Preferably it is 100,000-1,500,000, More preferably, it is 200,000-1,300,000, More preferably, it is 350,000-1,200,000, More preferably, it is 500,000-1,000,000. .

As acrylic resin used by one form of this invention, the structural unit (a1) derived from alkyl (meth) acrylate (a1 ') (henceforth also called "monomer (a1')", and a functional group containing monomer (a2 ') The acrylic copolymer (A1) which has a structural unit (a2) derived from () (hereafter also called "monomer (a2 ')") is more preferable.

As carbon number of the alkyl group which a monomer (a1 ') has, from a viewpoint of the improvement of adhesive characteristic, Preferably it is 1-24, More preferably, it is 1-12, More preferably, it is 2-10, More preferably, it is 4-8 to be.

Moreover, a linear alkyl group may be sufficient as the alkyl group which a monomer (a1 ') has, and a branched alkyl group may be sufficient as it.

As a monomer (a1 '), methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Usyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, etc. are mentioned.

These monomers (a1 ') may be used independently and may use 2 or more types together.

As a monomer (a1 '), butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.

Content of a structural unit (a1) becomes like this. Preferably it is 50-99.9 mass%, More preferably, 60-99.0 mass%, More preferably, with respect to the precursor unit (100 mass%) of an acryl-type copolymer (A1). 70-97.0 mass%, More preferably, it is 80-95.0 mass%.

As a functional group which a monomer (a2 ') has, a hydroxyl group, a carboxyl group, an amino group, an epoxy group, etc. are mentioned, for example.

That is, as a monomer (a2 '), a hydroxyl group containing monomer, a carboxyl group containing monomer, an amino group containing monomer, an epoxy group containing monomer, etc. are mentioned, for example.

These monomers (a2 ') may be used independently and may use 2 or more types together.

Among these, as a monomer (a2 '), a hydroxyl group containing monomer and a carboxyl group containing monomer are preferable.

As a hydroxyl group containing monomer, the same thing as the hydroxyl group containing compound mentioned above is mentioned, for example.

As a carboxyl group-containing monomer, For example, ethylenic unsaturated monocarboxylic acids, such as (meth) acrylic acid and crotonic acid; And ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid and anhydrides thereof, 2- (acryloyloxy) ethyl succinate, 2-carboxyethyl (meth) acrylate, and the like. .

As for content of a structural unit (a2), with respect to the precursor unit (100 mass%) of an acryl-type copolymer (A1), Preferably it is 0.1-40 mass%, More preferably, it is 0.5-35 mass%, More preferably, 1.0-30 mass%, More preferably, it is 3.0-25 mass%.

The acrylic copolymer (A1) may further have a structural unit (a3) derived from monomers (a3 ') other than monomer (a1') and (a2 ').

Moreover, in acrylic copolymer (A1), content of structural unit (a1) and (a2) becomes like this. Preferably it is 70-100 mass% with respect to the precursor unit (100 mass%) of an acrylic copolymer (A1). Preferably it is 80-100 mass%, More preferably, it is 90-100 mass%, More preferably, it is 95-100 mass%.

As a monomer (a3 '), For example, olefins, such as ethylene, propylene, isobutylene; Halogenated olefins such as vinyl chloride and vinylidene chloride; Diene monomers such as butadiene, isoprene and chloroprene; Cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth (Meth) acrylate which has cyclic structures, such as a) acrylate and an imide (meth) acrylate; Styrene, α-methylstyrene, vinyltoluene, vinyl formate, vinyl acetate, acrylonitrile, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmorpholine, N-vinylpyrrolidone, and the like. Can be.

The acrylic copolymer (A1) may be an energy ray-curable acrylic copolymer in which a polymerizable functional group is introduced into the side chain.

As said polymerizable functional group and the said energy ray, it is as having mentioned above.

In addition, a polymerizable functional group has the compound which has a substituent and a polymerizable functional group couple | bonded with the acryl-type copolymer which has the above-mentioned structural unit (a1) and (a2), and the functional group which the structural unit (a2) of the said acryl-type copolymer has. It can introduce | transduce by making it react.

As said compound, (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, glycidyl (meth) acrylate, etc. are mentioned, for example.

<Crosslinking system>

In one embodiment of the present invention, when the pressure-sensitive adhesive composition contains a pressure-sensitive resin containing the same functional group as the acrylic copolymer (A1) described above, it is preferable that the pressure-sensitive adhesive composition further contains a crosslinking agent.

The said crosslinking agent reacts with the adhesive resin which has a functional group, and bridge | crosslinks adhesive resins as said starting point of a functional group with a crosslinking origin.

As a crosslinking agent, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an aziridine type crosslinking agent, a metal chelate type crosslinking agent, etc. are mentioned, for example.

These crosslinking agents may be used independently and may use 2 or more types together.

Among these crosslinking agents, isocyanate-based crosslinking agents are preferable from the viewpoints of increasing the cohesive force to improve the adhesive force and the availability.

Although content of a crosslinking agent is adjusted suitably according to the number of functional groups which adhesive resin has, Preferably it is 0.01-10 mass parts, More preferably, it is 0.03-7 mass parts, More preferably, with respect to 100 mass parts of adhesive resin which has a functional group. Preferably it is 0.05-5 mass parts.

<Adhesive agent>

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

In this specification, an "adhesive tackifier" is a component which auxiliaryly improves the adhesive force of the above-mentioned adhesive resin, A mass mean molecular weight (Mw) points out an oligomer of less than 10,000, and distinguishes it from the above-mentioned adhesive resin.

The mass average molecular weight (Mw) of the tackifier is preferably 400 to 10,000, more preferably 500 to 8000, still more preferably 800 to 5000.

As a tackifier, C5 fractions, such as pentene, isoprene, piperine, 1, 3-pentadiene, which are produced | generated by the pyrolysis of rosin type resin, terpene type resin, styrene resin, and petroleum naphtha, are used, for example. C9 petroleum resin obtained by copolymerizing C9 petroleum resin obtained by copolymerizing C9 fractions, such as indene and vinyltoluene produced | generated by pyrolysis of petroleum naphtha, and hydrogenated resin which hydrogenated these.

The softening point of a tackifier becomes like this. Preferably it is 60-170 degreeC, More preferably, it is 65-160 degreeC, More preferably, it is 70-150 degreeC.

In addition, in this specification, the "softening point" of a tackifier means the value measured based on JISKK2531.

A tackifier may be used independently and may use together 2 or more types from which a softening point and a structure differ.

And when using 2 or more types of some tackifiers, it is preferable that the weighted average of the softening point of these some tackifiers falls in the said range.

Content of a tackifier becomes like this. Preferably it is 0.01-65 mass%, More preferably, it is 0.05-55 mass%, More preferably, 0.1-50 mass% with respect to whole quantity (100 mass%) of the active ingredient of an adhesive composition. More preferably, it is 0.5-45 mass%, More preferably, it is 1.0-40 mass%.

<Photoinitiator>

In one embodiment of the present invention, when the pressure-sensitive adhesive composition contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive resin, it is preferable to further contain a photopolymerization initiator.

By setting it as the adhesive composition containing an energy-ray-curable adhesive resin and a photoinitiator, the adhesive layer formed from the said adhesive composition can fully advance hardening reaction also by irradiation of a comparatively low energy energy ray, and can adjust adhesive force to a desired range. Will be.

Moreover, as a photoinitiator used by one form of this invention, the thing similar to what is mix | blended with the above-mentioned non-solvent type resin composition (y1) is mentioned.

Content of a photoinitiator becomes like this. Preferably it is 0.01-10 mass parts, More preferably, it is 0.03-5 mass parts, More preferably, it is 0.05-2 mass parts with respect to 100 mass parts of energy ray curable adhesive resins.

<Additive for adhesive>

In one embodiment of the present invention, the pressure-sensitive adhesive composition which is a material for forming the pressure-sensitive adhesive layer may contain an additive for pressure-sensitive adhesive used in a general pressure-sensitive adhesive, in addition to the above-mentioned additives within a range that does not impair the effects of the present invention.

As such an adhesive additive, antioxidant, a softener (plasticizer), an antirust agent, a pigment, a dye, a retarder, a reaction promoter (catalyst), a ultraviolet absorber, etc. are mentioned, for example.

In addition, these adhesive additives may be used independently, respectively and may use 2 or more types together.

When it contains such an adhesive additive, content of each adhesive additive is preferably 0.0001-20 mass parts, More preferably, it is 0.001-10 mass parts with respect to 100 mass parts of adhesive resin.

The adhesive composition which is a formation material of an adhesive layer may contain thermally expansible particle | grains in the range which does not impair the effect of this invention.

However, as mentioned above, it is preferable that the adhesive layer which the adhesive sheet of one form of this invention has is a non-thermally expansible adhesive layer. For this reason, the adhesive composition which is a formation material of the said adhesive layer is so preferable that there is very little content of thermally expansible particle | grains.

The content of the thermally expansible particles is preferably less than 5% by mass, more preferably less than 1% by mass, even more preferably less than 0.1% by mass, even more preferably based on the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition. Preferably it is less than 0.01 mass%, Especially preferably, it is less than 0.001 mass%.

[Peeling material]

Like the adhesive sheet 1b of FIG. 1 (b) and the adhesive sheet 2b of FIG. 2 (b), the adhesive sheet of one form of this invention may further have a peeling material on the sticking surface of an adhesive layer.

In addition, in the adhesive sheet which has two adhesive layers like the adhesive sheet 2b of FIG. 2 (b), the two peeling materials provided on the sticking surface of each adhesive layer are adjusted so that a difference of peeling force may differ. Is preferred.

As a peeling material, the peeling sheet which carried out the double-sided peeling process, the peeling sheet which carried out single sided peeling process, etc. are used, and what apply | coated the peeling agent on the base material for peeling materials, etc. are mentioned.

As a base material for peeling materials, For example, papers, such as a quality paper, glassine paper, and a kraft paper; Plastic films such as polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin and polyethylene naphthalate resin, and olefin resin films such as polypropylene resin and polyethylene resin; Etc. can be mentioned.

As a peeling agent, rubber type elastomers, such as silicone type resin, olefin type resin, isoprene type resin, butadiene type resin, long chain alkyl type resin, alkyd type resin, fluorine type resin etc. are mentioned, for example.

Although the thickness of a peeling material does not have a restriction | limiting in particular, Preferably it is 10-200 micrometers, More preferably, it is 25-170 micrometers, More preferably, it is 35-80 micrometers.

[Manufacturing Method of Adhesive Sheet]

There is no restriction | limiting in particular as a manufacturing method of the adhesive sheet of this invention, The manufacturing method (a) which has the following process (1a) and (2a) is mentioned.

Process (1a): The process of apply | coating the resin composition (y) which is a formation material of a thermally expansible base material, and forming a coating film on the peeling process surface of a peeling material, and drying or UV irradiation of the said coating film, and forming a thermally expansible base material.

Process (2a): The process of apply | coating the adhesive composition which is a formation material of an adhesive layer on the surface of the said thermally expansible base material, forming a coating film, and drying the said coating film to form an adhesive layer.

Moreover, as another manufacturing method of the adhesive sheet of this invention, the manufacturing method (b) which has the following process (1b)-(3b) is mentioned.

Process (1b): The process of apply | coating the resin composition (y) which is a formation material of a thermally expansible base material, and forming a coating film on the peeling process surface of a peeling material, and drying the said coating film to form a thermally expansible base material.

Process (2b): The process of apply | coating the adhesive composition which is a formation material of an adhesive layer on the peeling process surface of a peeling material to form a coating film, and drying the said coating film to form an adhesive layer.

Step (3b): A step of pasting the surface of the thermally expandable substrate formed in the step (1b) and the surface of the pressure-sensitive adhesive layer formed in the step (2b).

In the production methods (a) and (b), the resin composition (y) and the pressure-sensitive adhesive composition may further contain a diluent solvent to form a solution.

As a coating method, the spin coating method, the spray coating method, the bar coating method, the knife coating method, the roll coating method, the blade coating method, the die coating method, the gravure coating method, etc. are mentioned, for example.

Further, in the drying step of forming the thermally expandable base material with the coating film in the step (1a) of the manufacturing method (a) and the step (1b) of the manufacturing method, the drying temperature is prevented from the viewpoint of preventing expansion of the thermally expandable particles. Is preferably performed below the expansion start temperature t of the thermally expandable particles.

[Use of PSA Sheet of the Present Invention, Method of Using PSA Sheet]

The adhesive sheet of the present invention can be easily peeled off with a weak force at the time of peeling while suppressing the settling of the object at the time of heating when fixing the object temporarily.

For this reason, it is preferable that the adhesive sheet of this invention uses sealing resin, and is used at the sealing process with heating, and it is preferable to be used at the sealing process at the time of manufacturing a FOWLP specifically ,.

In the sealing process at the time of manufacturing a FOWLP, after mounting a semiconductor chip on the adhesive surface of the adhesive layer of the adhesive sheet of this invention, the upper surface and adhesive surface of a semiconductor chip are covered with sealing resin, and sealing resin is heated by heating. Heat cured and sealed.

At this time, when a general adhesive sheet is used, the elasticity modulus of each layer which comprises an adhesive sheet falls by the heating in a sealing process, and the semiconductor chip mounted is settled to the adhesive sheet side.

On the other hand, since the adhesive sheet of this invention satisfy | fills the said requirement (1), it effectively suppresses sedimentation to the adhesive sheet side of the semiconductor chip which may arise in the sealing process, and flattens the surface of the semiconductor chip side after sealing. In addition to this, the occurrence of positional shift of the semiconductor chip can be suppressed.

As sealing resin, arbitrary things can be suitably selected from what is used as a semiconductor sealing material, For example, what contains a thermosetting resin and an energy-beam curable resin is mentioned.

Moreover, as a form of sealing resin, it may be solid, such as a granular form and a film form at room temperature, and may be a liquid substance with fluidity like a composition, but it is preferable that it is a film form from a viewpoint of workability.

As a method of coating a semiconductor chip and its peripheral part using sealing resin, it can conventionally select and apply suitably according to the kind of sealing material among the methods currently applied to the semiconductor sealing process, For example, the roll lamination method, The vacuum press method, the vacuum lamination method, the spin coating method, the die coating method, the transfer molding method, the compression molding mold method and the like can be applied.

Moreover, it is preferable that a sealing process is performed on temperature conditions less than the expansion start temperature t of thermally expansible particle | grains.

In addition, although coating | covering process and thermosetting treatment of sealing resin may be performed separately, when heating sealing resin by coating | covering process, you may harden an sealing material by the said heating as it is, and may perform coating | coating process and thermosetting treatment simultaneously. good.

On the other hand, after the sealing step is completed, the pressure-sensitive adhesive sheet can be easily peeled off with a weak force by heating to a temperature equal to or higher than the expansion start temperature t.

As "temperature above expansion start temperature t" at the time of peeling an adhesive sheet, it is preferable that it is "expansion start temperature t + 10 degreeC" or more "expansion start temperature t + 60 degreeC" or less, and "expansion start temperature ( It is more preferable that it is "t) +15 degreeC" or more and "expansion start temperature t + 40 degreeC" or less.

Moreover, from the above-mentioned characteristic of the adhesive sheet of this invention, this invention can also provide the usage method of the adhesive sheet of following [1].

 [1] A method of using an adhesive sheet, wherein the adhesive sheet of the present invention described above is attached to the adherend, and then the adhesive sheet is peeled from the adherend by heat treatment at an expansion start temperature t or more.

Moreover, it is preferable that the said use method uses sealing resin, and is used in the sealing process with heating.

Example

Although this invention demonstrates concretely by the following example, this invention is not limited to a following example. In addition, the physical-property value in the following manufacture examples and examples is the value measured according to the following method.

<Mass average molecular weight (Mw)>

The gel permeation chromatography apparatus (manufactured by TOSOH CORPORATION, product name "HLC-8020") was used under the following conditions, and the value measured by standard polystyrene conversion was used.

(Measuring conditions)

Column: A sequence of `` TSK guard column HXL-L '' `` TSK gel G2500HXL '' `` TSK gel G2000HXL '' `` TSKTSgel G1000HXL '' (all manufactured by TOSOH CORPORATION)

Column temperature: 40 ℃

Developing solvent: tetrahydrofuran

Flow rate: 1.0 mL / min

<Measurement of the thickness of each layer>

It measured using the static-pressure thickness meter (a model number: "PG-02J", a standard standard: based on JIS67K6783, Z1702, Z1709) made from TECLOCK Co., Ltd.).

<Average particle size (D ₅₀ ), 90% particle size (D ₉₀ ) of thermally expandable particles>

The particle distribution of the thermally expandable particles before expansion was measured at 23 ° C. using a laser diffraction particle size distribution measuring device (for example, manufactured by Malzern, product name “MASTERSIZER 3000”).

Then, the particle size of the cumulative volume frequency calculated toward the small of a particle size distribution the particle diameter corresponding to 50% and 90%, respectively, "average particle diameter of the heat-expandable particles (D _50)" or the 90% particle diameter of the "heat-expandable particles (D ₉₀ ).

<Storage Modulus (E ') of Thermally Expandable Substrate>

When the measurement object was a non-adhesive heat-expandable base material, the heat-expandable base material was made into the size of 5 mm x 30 mm in width x 200 µm in thickness, and the peeling material was removed as a test sample.

Using a dynamic viscoelasticity measuring device (product name "DMAQ800" manufactured by TA Instruments), the test start temperature is 0 ° C, the test end temperature is 300 ° C, the heating rate is 3 ° C / min, the frequency is 1 Hz, and the amplitude is 20 μm. The storage modulus (E) of the test sample at the temperature was measured.

<Storage shear modulus (G ') of the adhesive layer, storage modulus (E') of the heat-expandable pressure-sensitive adhesive layer>

When the measurement object was a thermally expansible adhesive layer and an adhesive layer which have adhesiveness, the said thermally expansible adhesive layer and the adhesive layer were made into 8 mm diameter x 3 mm in thickness, and what removed the peeling material was used as the test sample.

By using the viscoelasticity measuring device (manufactured by Anton'Paar, device name "MCR300") under the conditions of the test start temperature of 0 ° C, the test end temperature of 300 ° C, the temperature increase rate of 3 ° C / min, and the frequency of 1 Hz, The storage shear modulus (G ＇) of the test sample at a predetermined temperature was measured.

And the value of storage elastic modulus (E ') was computed from the approximation formula "E' = 3G '" based on the value of the measured storage shear modulus (G').

<Probe tack value>

After cutting the heat-expandable base material or the heat-expandable pressure-sensitive adhesive layer to be a square of 10 mm on one side, the resultant was allowed to stand for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity) to remove the light peeling film as a test sample. did.

Under the environment of 23 ° C. and 50% RH (relative humidity), the test sample of the test sample, which was expressed by removing a light peeling film using a tagging tester (manufactured by NIPPON TOKUSHU SOKKI CO., LTD., Product name “NTS-4800”), was used. The probe tack value on the surface was measured in accordance with JIS # Z0237: 1991.

Specifically, a stainless steel probe having a diameter of 5 mm was brought into contact with the surface of the test sample at a contact load of 0.98 N / cm 2 for 1 second, and then the probe was removed from the surface of the test sample at a rate of 10 mm / sec. The force required to release was measured. And the measured value was made into the probe tack value of the test sample.

The detail of the adhesive resin, the additive, thermally expansible particle | grains, and peeling material used for formation of each layer in the following manufacture examples is as follows.

<Adhesive resin>

Acrylic copolymer (i): Mw 60 which has a structural unit derived from the raw material monomer which consists of 2-ethylhexyl acrylate (2EHA) / 2-hydroxyethyl acrylate (HEA) = 80.0 / 20.0 (mass ratio). A solution containing only an acrylic copolymer. Diluent solvent: ethyl acetate, solid content concentration: 40 mass%.

Acrylic copolymer (ii): n-butyl acrylate (BA) / methyl methacrylate (MMA) / 2-hydroxyethyl acrylate (HEA) / acrylic acid = 86.0 / 8.0 / 5.0 / 1.0 (mass ratio) The solution containing the acrylic copolymer of Mw 600,000 having a structural unit derived from a raw material monomer. Diluent solvent: ethyl acetate, solid content concentration: 40 mass%.

<Additive>

Isocyanate crosslinking agent (i): Product made from TOSOH CORPORATION, a product name "Coronate L", solid content concentration: 75 mass%.

Photoinitiator (i): The product name "IRGACURE 184" by BASF Corporation, 1-hydroxy cyclohexyl phenyl- ketone.

<Thermally expandable particle>

Thermally expandable particles (i): KUREHA CORPORATION, product name "S2640", expansion start temperature (t) = 208 ° C Average particle size (D ₅₀ ) = 24 µm, 90% particle diameter (D ₉₀ ) = 49 µm.

<Peel material>

-Heavy peeling film: The product name "SP-PET382150" made from LINTEC Corporation, and having provided the release agent layer formed from the silicone type release agent on one side of a polyethylene terephthalate (PET) film, thickness: 38 micrometers.

Hard peeling film: The product name "SP-PET381031" made from LINTEC Corporation, and having provided the release agent layer formed from the silicone type release agent on one side of PET film, thickness: 38 micrometers.

Production Example 1 (Formation of First Adhesive Layer (X-1))

5.0 mass parts (solid content ratio) of the said isocyanate type crosslinking agent (i) is mix | blended with 100 mass parts of solid content of the said acryl-type copolymer (i) which is adhesive resin, and it diluted with toluene, stirred uniformly, solid content concentration (effective component concentration) ) 25 mass% of composition (x-1) was prepared.

On the surface of the release agent layer of the heavy release film, the prepared composition (x-1) is applied to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to form a first adhesive layer having a thickness of 10 μm (X−). 1) formed.

Moreover, the storage shear modulus (G ') 23 of the 1st adhesive layer (X-1) at 23 degreeC was 2.5 * 10 <^5> Pa.

Production Example 2 (Formation of Second Adhesive Layer (X-2))

0.8 mass parts (solid content ratio) of the said isocyanate type crosslinking agent (i) is mix | blended with 100 mass parts of solid content of the said acrylic copolymer (ii) which is adhesive resin, and it diluted with toluene, stirred uniformly, solid content concentration (effective component) Concentration) 25 mass% of the composition (x-2) was prepared.

On the surface of the release agent layer of the light peeling film, the prepared composition (x-2) is applied to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to form a second adhesive layer having a thickness of 10 μm (X−). 2) formed.

Moreover, the storage shear modulus (G ') 23 of 2nd adhesive layer (X-2) was 23 * 10 <^4> Pa at 23 degreeC.

Production Example 3 (Formation of Thermally Expandable Substrate (Y-1))

(1) Preparation of Composition (y-1)

2-hydroxyethyl acrylate was made to react with the terminal isocyanate urethane prepolymer obtained by making ester type diol and isophorone diisocyanate (IPDI) react, and the bifunctional acrylic urethane oligomer of the mass mean molecular weight (Mw) 5000 was obtained.

40 mass% (solid content ratio) of isobornyl acrylate (IBXA) as an energy-beam polymerizable monomer, and 40 mass% (solid content ratio) of the acryl urethane oligomer synthesize | combined above, and phenyl hydroxypropyl acrylate (HPPA) 20 Mixing mass% (solid content ratio), 1-hydroxycyclohexyl phenyl ketone (made by BASF, product name "IRGACURE 184") 2.0 as a photoinitiator with respect to 100 mass parts of total amounts of an acryl urethane type oligomer and an energy-beam polymerizable monomer. 0.2 mass part (solid content ratio) of a phthalocyanine-type pigment was further mix | blended as a mass part (solid content ratio) and an additive, and the energy ray curable composition was prepared.

And the said heat-expandable particle | grain (i) was mix | blended with the said energy-beam curable composition, and the composition (y-1) of the non-solvent type which does not contain a solvent was prepared.

Moreover, content of thermally expansible particle | grains (i) with respect to whole quantity (100 mass%) of composition (y-1) was 20 mass%.

(2) Formation of Thermally Expandable Substrate (Y-1)

The prepared composition (y-1) was apply | coated on the surface of the peeling agent layer of the said light peeling film, and the coating film was formed.

Then, using an ultraviolet irradiation device (EYE GRAPHICS., Ltd., product name "ECS-401 GX") and a high pressure mercury lamp (EYE GRAPHICS., Ltd., product name "H04-L41"), illuminance 160 mW / Ultraviolet was irradiated on conditions of cm <2> and light quantity 500mJ / cm <2>, and the said coating film was hardened | cured and the thermally expansible base material (Y-1) of 50 micrometers in thickness was formed. In addition, the said illumination intensity and light quantity at the time of ultraviolet irradiation are the value measured using the illumination intensity and the light quantity meter (the product name "UV" Power "Puck" II "by EIT Corporation).

Production Example 4 (Formation of Thermally Expandable Substrate (Y-2))

(1) Synthesis of Urethane Prepolymer

Isophorone diisocyanate (IPDI) is equivalent ratio of the hydroxyl group of polycarbonate-type diol, and the isocyanate group of isophorone diisocyanate with respect to 100 mass parts (solid content ratio) of carbonate-type diol of mass mean molecular weight 1,000 in reaction container in nitrogen atmosphere. Is mix | blended so that it may become 1/1, and 160 mass parts of toluene were further added, and it stirred at 80 degreeC for 6 hours or more until the isocyanate group concentration reached the theoretical amount, stirring in nitrogen atmosphere.

Then, a solution obtained by diluting 1.44 parts by mass of 2-hydroxyethyl methacrylate (2-HEMA) (solid content ratio) to 30 parts by mass of toluene was added, and then, at 80 ° C, until the isocyanate group at the end of the dissipation disappeared. The reaction was further carried out to obtain a urethane prepolymer having a mass average molecular weight of 2.9 million.

(2) Synthesis of Acrylic Urethane Resin

In a reaction vessel under a nitrogen atmosphere, 100 parts by mass of the urethane prepolymer (solid content ratio) obtained in the above (1), 117 parts by mass of methyl methacrylate (MMA) (solid content ratio), 2-hydroxyethyl methacrylate (2- HEMA) 5.1 mass parts (solid content ratio), 1.1 mass parts (solid content ratio) of 1-thioglycerol, and 50 mass parts of toluene were added, and it heated up to 105 degreeC, stirring.

And in the reaction container, the solution which diluted 2.2 mass parts (solid content ratio) of radical initiator (Japan Finechem Inc., product name "ABN-E") to 210 mass parts of toluene was further maintained over 105 hours over 4 hours. Dropped.

After completion of dropwise addition, the mixture was reacted at 105 ° C for 6 hours to obtain a solution of acrylic urethane resin having a mass average molecular weight of 10.5 million.

(3) Formation of Thermally Expandable Substrate (Y-2)

1.4 mass parts of said isocyanate type crosslinking agents (i) (solid content ratio) and a catalyst 1.4 mass of dioctyl tin bis (2-ethylhexanoate) with respect to 100 mass parts of solid content of the solution of the acrylic urethane resin obtained by said (2). A part (solid content ratio) and the said thermally expansible particle | grains (i) were mix | blended, and it diluted with toluene, stirred uniformly, and prepared the composition (y-2) of 30 mass% of solid content concentration (active component concentration).

Moreover, content of thermally expansible particle | grains (i) with respect to whole quantity (100 mass%) of the active ingredient in obtained composition (y-2) was 20 mass%.

Then, on the surface of the release agent of the light peeling film, the prepared composition (y-2) is applied to form a coating film, and the coating film is dried at 100 ° C. for 120 seconds to form a thermally expandable substrate (Y-2) having a thickness of 50 μm. Formed.

Production Example 5 (Formation of Thermally Expandable Adhesive Layer (Y-3))

6.3 mass parts (solid content ratio) of the said isocyanate type crosslinking agent (i), and the said thermally expansible particle | grains (i) are mix | blended with 100 mass parts of solid content of the said acrylic copolymer (ii) which is adhesive resin, and it dilutes with toluene, It stirred uniformly and prepared the composition (y-3) of 30 mass% of solid content concentration (active component concentration).

Moreover, content of thermally expansible particle | grains (i) with respect to whole quantity (100 mass%) of the active ingredient in obtained composition (y-3) was 20 mass%.

And on the surface of the release agent layer of the said light peeling film, the prepared composition (y-3) is apply | coated and a coating film is formed, The said coating film is dried at 100 degreeC for 120 second, and the thermally expansible adhesive layer (Y- of thickness 50micrometer) is carried out. 3) formed.

Production Example 6 (Formation of Thermally Expandable Substrate (Y-4))

(1) Synthesis of Acrylic Copolymer (iii)

52 mass parts of n-butyl acrylate (BA), 20 mass parts of methyl methacrylate (MMA), and 28 mass parts of 2-hydroxyethyl acrylate (HEA) are solution-polymerized in an ethyl acetate solvent, and it is a non-energy-ray-curable An acrylic copolymer was obtained.

Regarding the total number of hydroxyl groups of the obtained acrylic copolymer, methacryloyloxyethyl isocyanate (MOI) in an amount such that the number of isocyanate groups is 0.9 equivalent is added to the solution containing the acrylic copolymer and reacted to the side chain. The energy-beam curable acrylic copolymer (iii) of Mw 1 million having a methacryloyl group was obtained.

(2) Formation of Thermally Expandable Substrate (Y-4)

And 0.5 mass part (solid content ratio) of the said isocyanate type crosslinking agent (i) and the said photoinitiator (i) are 3.0 mass parts with respect to 100 mass parts of solid content of the energy-beam curable acrylic copolymer (iii) obtained by said (1). A mass part (solid content ratio) and the said thermally expansible particle | grains (i) were mix | blended, and it diluted with toluene, stirred uniformly, and prepared the composition (y-4) of 30 mass% of solid content concentration (active component concentration).

Moreover, content of the thermally expansible particle (1) with respect to whole quantity (100 mass%) of the active ingredient in obtained composition (y-4) was 20 mass%.

And on the surface of the release agent layer of the said light peeling film, the prepared composition (y-4) is apply | coated and a coating film is formed, and after drying the said coating film at 100 degreeC for 120 second, roughness 160mW / cm <2>, light quantity 500mJ Ultraviolet rays were irradiated under the condition of / cm 2 to form a thermally expandable substrate (Y-4) having a thickness of 50 µm. In addition, the said illumination intensity and light quantity at the time of ultraviolet irradiation are the value measured using the illumination intensity and the light quantity meter (the product name "UV" Power "Puck" II "by EIT Corporation).

The method described above for the thermally expandable base materials (Y-1) to (Y-2) and (Y-4) formed in Production Examples 3 to 4 and 6 and the thermally expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5. Based on the above, the storage elastic modulus (E ′) was measured at 23 ° C., 100 ° C., and 208 ° C. which is the expansion start temperature of the used thermally expandable particles, and the probe tack value on the surface was also measured, respectively. These results are shown in Table 1.

Example 1

After exposing the surfaces of the first adhesive layer (X-1) formed in Production Example 1 and the thermally expandable substrate (Y-1) formed in Production Example 3 to each other, light peeling on the thermally expandable substrate (Y-1) side The film was removed, and the second adhesive layer (X-2) formed in Production Example 2 was stuck to each other on the surface of the exposed thermally expandable substrate (Y-1).

Adhesive sheet (1) which laminated | stacked light peeling film / 2nd adhesive layer (X-2) / thermally expansible base material (Y-1) / 1st adhesive layer (X-1) / heavy peeling film in this order by this Made.

Example 2

In the same manner as in Example 1, except that the thermally expandable substrate (Y-1) was replaced with the thermally expandable substrate (Y-2) formed in Production Example 4, the light-peelable film / second adhesive layer (X-2) / The adhesive sheet 2 which laminated | stacked the thermally expansible base material (Y-2) / 1st adhesive layer (X-1) / heavy peeling film in this order was produced.

Comparative Example 1

The exposed surfaces of the second adhesive layer (X-2) formed in Production Example 2 and the thermally expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5 were bonded to each other.

And the 1st adhesive layer (X-1) formed in the manufacture example 1 on the surface of the heat-expandable adhesive layer (Y-3) which removed and removed the light peeling film of the heat-expandable adhesive layer (Y-3) side. Glued together.

Adhesive sheet which laminated | stacked light peeling film / 2nd adhesive layer (X-2) / thermally expansible adhesive layer (Y-3) / 1st adhesive layer (X-1) / heavy peeling film in this order by this )

Comparative Example 2

In the same manner as in Example 1 except that the thermally expandable substrate (Y-1) was replaced with the thermally expandable substrate (Y-4) formed in Production Example 6, the light-peelable film / second adhesive layer (X-2) / The adhesive sheet 4 which laminated | stacked the thermally expansible base material (Y-4) / 1st adhesive layer (X-1) / heavy peeling film in this order was produced.

Comparative Example 3

The exposed surfaces of the second adhesive layer (X-2) formed in Production Example 2 and the heat-expandable pressure-sensitive adhesive layer (Y-3) formed in Production Example 5 are bonded to each other, and the light peeling film / second adhesive layer (X-2) ), The heat-expandable adhesive layer (Y-3) / the adhesive sheet 5 which laminated | stacked the light peeling film in this order was produced.

In addition, the following measurement was performed about the produced adhesive sheets 1-(5). These results are shown in Table 2.

<Position misalignment evaluation of the semiconductor chip at the time of sealing process>

The light peeling film on the side of the 2nd adhesive layer (X-2) which the produced adhesive sheets 1-5 has was removed, and the adhesive surface of the exposed 2nd adhesive layer (X-2) was stuck with a support body. .

And the heavy peeling film of the adhesive sheets 1-4, and the light peeling film of the other of the adhesive sheet 5 are removed, and the 1st adhesive layer (X-1) or thermally expansible adhesive layer (Y) which were exposed was exposed. On the adhesive surface of -3), nine semiconductor chips (each chip size is 6.4mm x 6.4mm, chip thickness is 200μm (＃ 2000)) so that the circuit surface of each semiconductor chip is in contact with the adhesive surface, It was placed at the required interval.

Then, the resin film for sealing was laminated | stacked on the adhesion surface and the semiconductor chip, the semiconductor chip was sealed using the vacuum heating press laminator ("7024 HP5" by ROHM'and HAAS), and the sealing body was produced.

In addition, sealing conditions are as follows.

Preheating temperature: 100 ° C for both tables and diagrams

Vacuum: 60 seconds

Dynamic press mode: 30 seconds

Static press mode: 10 seconds

Encapsulation temperature: 180 ° C (temperature lower than 208 ° C, which is the expansion start temperature of thermally expandable particles)

Encapsulation time: 60 minutes

After encapsulation, the adhesive sheets 1 to 5 were heated at 240 ° C. for expansion expansion temperature of the thermally expandable particles (240 ° C. or more) for 3 minutes to separate the encapsulation bodies from the adhesive sheets 1 to 5. The semiconductor chip of the surface of the separated sealing body (the surface on which the adhesive sheet was affixed) was observed by visual observation and a microscope, and the presence or absence of position shift of the semiconductor chip was confirmed, and the following references | standards evaluated.

A: The semiconductor chip which generate | occur | produced the position shift more than 25 micrometers than before sealing was not confirmed.

F: The semiconductor chip which produced 25 micrometers or more of position shift | deviation than before sealing was confirmed.

<Evaluation of the flatness of the surface of the semiconductor chip side after a sealing process>

Contact surface roughness meter ("SV3000" made by Mitutoyo Corporation) for the surface of the semiconductor chip side of the sealing body which isolate | separated the adhesive sheet (1)-(5) obtained by the above-mentioned "position misalignment evaluation of the semiconductor chip at the time of sealing process". The level | step difference was measured using and the following references | standards evaluated.

A: The location where the step | step with 2 micrometers or more arise was not recognized.

F: The location where the step | step with 2 micrometers or more generate | occur | produced was confirmed.

<Measurement of the adhesive force of the adhesive sheet before and after heating>

50 micrometers in thickness on the adhesive surface of the 2nd adhesive layer (X-2) which remove | eliminated the light peeling film by the side of the 2nd adhesive layer (X-2) which the produced adhesive sheets (1)-(5) have Polyethylene terephthalate (PET) film (manufactured by TOYOBO CO., LTD., Product name "Cosmo Shine A4100") was laminated to obtain an adhesive sheet with a base material.

And the heavy peeling film of the adhesive sheets 1-4 (4), and the light peeling film of the other of the adhesive sheet 5 is also removed, and the 1st adhesive layer (X-1) or thermally expansible adhesive layer (Y) which were expressed was removed. The adhesive surface of -3) was affixed on the stainless steel plate (SUS304 # 360 grinding | polishing) which is a to-be-adhered body, and the test sample was made to stand for 24 hours in 23 degreeC and 50% RH (relative humidity) environment.

And using the said test sample, under 23 degreeC and 50% RH (relative humidity) environment, based on JIS Z0237: 2000, according to 180 degree peeling method, it is 23 degreeC by the tensile velocity of 300 mm / min. The adhesive force of was measured.

Further, the above test sample was heated on a hot plate for 3 minutes at 240 ° C. which became the expansion start temperature (208 ° C.) or higher of the thermally expansible particles, and was 60 in a standard environment (23 ° C., 50% RH (relative humidity)). After standing still, based on JIS Z0237: 2000, the adhesive force after heating to the expansion start temperature or more was also measured with the tensile velocity of 300 mm / min according to the 180 degree peeling method.

Moreover, when measurement of adhesive force was difficult so that it could not stick to the stainless steel plate which is a to-be-adhered body, it was called "measurement impossible" and the adhesive force was 0 (N / 25mm).

From Table 2, since the adhesive sheets 1 and 2 of Examples 1 and 2 have the high suppression effect of sedimentation of a semiconductor chip at the time of the heating at the time of a sealing process, neither the position shift of a semiconductor chip is seen, nor sealing The surface of the semiconductor chip side after a process was also flat.

In addition, although the adhesive sheets 1 and 2 have a favorable adhesive force before heating, since adhesive force falls to the extent that it becomes impossible to measure after heating beyond the expansion start temperature, it is weak at the time of peeling. The result proved that it can peel easily.

In addition, since the adhesive sheet 3 of the comparative example 1 and the adhesive sheet 5 of the comparative example 3 have not a thermally expansible base material but a thermally expansible adhesive layer, sedimentation of a semiconductor chip at the time of the heating at the time of a sealing process It occurred, the position shift of the semiconductor chip was seen, and the step | step was seen on the surface of the semiconductor chip side after a sealing process. For this reason, it is considered unsuitable for use in the sealing process at the time of manufacturing a FOWLP, for example.

Moreover, the adhesive force before and after the heating of the adhesive sheet 4 of the comparative example 2 or more does not change so much, and it became a result which cannot be peeled off by heating.

1a, 1b: adhesive sheet
2a, 2b: double-sided adhesive sheet
11: thermally expandable substrate
12: adhesive layer
121: first adhesive layer
122: second adhesive layer
13, 131, 132: release material
50: FOWLP
51: semiconductor chip
52: bag resin layer
53: redistribution layer
54: solder ball

Claims (12)

A non-tacky heat-expandable base material comprising a resin, and heat-expandable particles having an expansion start temperature (t) of 120 to 250 ° C, and
Pressure-sensitive adhesive layer containing an adhesive resin,
As an adhesive sheet having a,
The thermally expandable base material satisfies the following requirements (1) to (2).
Requirement (1): The storage elastic modulus (Ek) 100 of the thermally expandable substrate is 100 × 10 ⁵ Pa or more at 100 ° C.
Requirement (2): The storage elastic modulus (E) (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles. The method of claim 1,
The said heat-expandable base material satisfy | fills the following requirements (3).
Requirements (3): The storage elastic modulus (E ′) 23 of the thermally expandable substrate at 23 ° C. is 1.0 × 10 ⁶ Pa or more. The method according to claim 1 or 2,
The adhesive sheet whose ratio (heat-expandable base material / adhesive layer) of the thickness of the said thermally expansible base material and the thickness of the said adhesive layer is 0.2 or more at 23 degreeC. The method according to any one of claims 1 to 3,
The adhesive sheet whose thickness of the said heat-expandable base material is 10-1000 micrometers at 23 degreeC, and the thickness of the said adhesive layer is 1-60 micrometers. The method according to any one of claims 1 to 4,
The adhesive sheet whose probe tack value on the surface of the said thermally expansible base material is less than 50 mN / 5mm (phi). The method according to any one of claims 1 to 5,
The adhesive sheet in which the storage shear modulus (G ') (23) of the said adhesive layer is 1.0 * 10 <^4> -1.0 * 10 <^8> Pa at 23 degreeC. The method according to any one of claims 1 to 6,
The adhesive sheet which has two said adhesive layers, respectively, on both surfaces of the said thermally expansible base material. The method according to any one of claims 1 to 7,
The adhesive sheet whose average particle diameter before expansion at 23 degreeC of the said thermally expansible particle is 3-100 micrometers. The method according to any one of claims 1 to 8,
The adhesive sheet which uses sealing resin and is used in the sealing process with heating. A thermally expandable base material comprising a resin and thermally expandable particles having an expansion start temperature (t) of 120 to 250 ° C, which is non-tacky, and satisfies the following requirements (1) to (2).
Requirement (1): The storage elastic modulus (Ek) 100 of the thermally expandable substrate is 100 × 10 ⁵ Pa or more at 100 ° C.
Requirement (2): The storage elastic modulus (E) (t) of the thermally expandable substrate is 1.0 × 10 ⁷ Pa or less at the expansion start temperature t of the thermally expandable particles. The method of using the pressure sensitive adhesive sheet, wherein the pressure sensitive adhesive sheet according to any one of claims 1 to 9 is attached to the adherend and then the adhesive sheet is peeled from the adherend by heat treatment at an expansion start temperature (t) or more. The method of claim 11,
The method of using an adhesive sheet which uses sealing resin and is used in the sealing process with heating.

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