CN110462816B - Method for manufacturing semiconductor device and adhesive sheet - Google Patents

Method for manufacturing semiconductor device and adhesive sheet Download PDF

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Publication number
CN110462816B
CN110462816B CN201880022421.0A CN201880022421A CN110462816B CN 110462816 B CN110462816 B CN 110462816B CN 201880022421 A CN201880022421 A CN 201880022421A CN 110462816 B CN110462816 B CN 110462816B
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CN
China
Prior art keywords
adhesive
adhesive layer
semiconductor chip
expandable particles
mass
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CN201880022421.0A
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Chinese (zh)
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CN110462816A (en
Inventor
阿久津高志
冈本直也
中山武人
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Lintec Corp
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Lintec Corp
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Publication of CN110462816A publication Critical patent/CN110462816A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/89—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using at least one connector not provided for in any of the groups H01L24/81 - H01L24/86
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J5/00—Adhesive processes in general; Adhesive processes not provided for elsewhere, e.g. relating to primers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/50—Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
    • H01L21/56—Encapsulations, e.g. encapsulation layers, coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/12—Mountings, e.g. non-detachable insulating substrates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/28—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection
    • H01L23/31—Encapsulations, e.g. encapsulating layers, coatings, e.g. for protection characterised by the arrangement or shape
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/52—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames
    • H01L23/522—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body
    • H01L23/525—Arrangements for conducting electric current within the device in operation from one component to another, i.e. interconnections, e.g. wires, lead frames including external interconnections consisting of a multilayer structure of conductive and insulating layers inseparably formed on the semiconductor body with adaptable interconnections
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/04105—Bonding areas formed on an encapsulation of the semiconductor or solid-state body, e.g. bonding areas on chip-scale packages
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10—Bump connectors; Manufacturing methods related thereto
    • H01L2224/12—Structure, shape, material or disposition of the bump connectors prior to the connecting process
    • H01L2224/12105—Bump connectors formed on an encapsulation of the semiconductor or solid-state body, e.g. bumps on chip-scale packages
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/93—Batch processes
    • H01L2224/95—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips
    • H01L2224/96—Batch processes at chip-level, i.e. with connecting carried out on a plurality of singulated devices, i.e. on diced chips the devices being encapsulated in a common layer, e.g. neo-wafer or pseudo-wafer, said common layer being separable into individual assemblies after connecting

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Adhesive Tapes (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Dicing (AREA)
  • Die Bonding (AREA)
  • Laminated Bodies (AREA)

Abstract

The present invention provides a method for producing a semiconductor device having steps (1) to (4) and a method for producing a semiconductor device using an adhesive sheet having an adhesive layer and a non-adhesive base material containing expandable particles, and an adhesive sheet used in the method. Step (1): a step of adhering the frame member having the opening formed thereon to the adhesive surface of the adhesive layer; step (2): a step of placing a semiconductor chip on a part of an adhesive surface of the adhesive layer exposed at the opening of the frame member; step (3): a step of covering a peripheral portion of the semiconductor chip, the frame member, and the adhesive surface of the adhesive layer with a sealing material, and curing the sealing material to obtain a cured sealing body in which the semiconductor chip is sealed with the cured sealing material; step (4): and a step of expanding the expandable particles and peeling the adhesive sheet from the cured sealing body. The invention can restrain the semiconductor chip from generating position deviation in the manufacturing process of fan-out type package, and has excellent productivity, and the obtained semiconductor device has excellent flatness of the rewiring layer forming surface.

Description

Method for manufacturing semiconductor device and adhesive sheet
Technical Field
The present invention relates to a method for manufacturing a semiconductor device and an adhesive sheet.
Background
In recent years, miniaturization, weight saving, and higher functionality of electronic devices have been advanced, and along with this, miniaturization, thickness reduction, and higher density of semiconductor devices mounted in electronic devices have been demanded.
Semiconductor chips are sometimes mounted in packages that are close to their size. Such packages are sometimes also referred to as CSPs (chip scale packages, chip Scale Package). As CSP, there may be mentioned: WLP (wafer level package ) completed with a wafer size processed to a final packaging process, PLP (panel level package ) completed with a panel size larger than the wafer size processed to a final packaging process, and the like.
WLP and PLP can be classified into Fan-In type and Fan-Out type. In the fan-out WLP (hereinafter, also referred to as "FOWLP") and PLP (hereinafter, also referred to as "FOPLP"), a semiconductor chip is covered with a sealing material to form a region larger than the chip size, and a semiconductor chip sealing body is formed, and a rewiring layer and an external electrode are formed not only on the circuit surface of the semiconductor chip but also on the surface region of the sealing material.
Further, FOWLP and FOPLP can be manufactured, for example, by the following steps: a step of placing a plurality of semiconductor chips on an adhesive sheet for temporary fixation (hereinafter, also referred to as a "temporary fixation sheet"), a step of covering the semiconductor chips with a sealing material having fluidity, a step of curing the sealing material by heat, a step of peeling the temporary fixation sheet from the sealing material, and a step of forming a rewiring layer on the exposed surface of the semiconductor chips.
The temporary fixing sheet used in the above-described steps is required to have adhesion properties such that the semiconductor chip is not displaced between the coating step and the curing step (hereinafter, these steps are also referred to as "sealing step") and the sealing material does not enter the adhesion interface between the semiconductor chip and the temporary fixing sheet, and to have peelability that can be easily removed without adhesive residue after the sealing step. That is, the temporary fixing sheet used for the production of FOWLP and FOPLP is required to have both adhesion at the time of use and releasability after use.
For example, patent document 1 discloses the following method: in the FOWLP manufacturing method, after a sealing step is performed on a temporary fixing sheet having a base material formed of a polyimide film and an adhesive layer formed of a silicone adhesive provided on the surface of the base material, the temporary fixing sheet is bent by hand and peeled off. However, the step of peeling the temporary fixing sheet by hand or the like is complicated, and from the viewpoint of improving productivity, it is required that the temporary fixing sheet can be peeled off with a smaller external force.
As a temporary fixing sheet excellent in releasability, for example, patent document 2 discloses a heat-peelable adhesive sheet for temporary fixing at the time of cutting an electronic component, which is provided with a heat-expandable adhesive layer containing heat-expandable microspheres on at least one surface of a base material. In the production of FOWLP and FOPLP, a heat-peelable pressure-sensitive adhesive sheet described in patent document 2 may be used.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2015-32646
Patent document 2: japanese patent No. 3594853
Disclosure of Invention
Problems to be solved by the invention
However, according to the studies by the present inventors, it is found that when the heat-peelable adhesive sheet described in patent document 2 is used as a temporary fixing sheet in the production of FOWLP and FOPLP, the semiconductor chips placed on the adhesive sheet side in the placing step and the sealing step are shifted in position because the elastic modulus of the thermally expandable adhesive layer is low. As a result, after the sealing step, a step is generated between the surface of the semiconductor chip and the surface of the sealing material on the surface of the semiconductor chip side from which the adhesive sheet has been removed (hereinafter, also referred to as "rewiring layer formation surface"), and thus, the flatness is deteriorated and the positional accuracy of the semiconductor chip is lowered. Such a decrease in the flatness of the rewiring layer formation surface and a decrease in the positional accuracy of the semiconductor chip cause a decrease in the rewiring accuracy, and thus suppression is desired.
In addition, it is considered that, when the adhesive sheet is removed, even if the heat-expandable adhesive layer is expanded by heating, the semiconductor chip is already immersed in the adhesive sheet side, and therefore, peeling is difficult without an external force of a certain magnitude.
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a method for manufacturing a semiconductor device, which can suppress positional displacement of a semiconductor chip in a manufacturing process of a fan-out package, is excellent in productivity, and is excellent in flatness of a re-wiring layer formation surface of the obtained semiconductor device, and an adhesive sheet usable in the manufacturing method.
Means for solving the problems
The present inventors have found that the above-described problems can be solved by using an adhesive sheet having a specific layer structure including a base material that contains expandable particles and is non-adhesive in a process for manufacturing a fan-out package.
That is, the present invention relates to the following [1] to [11].
[1] A method for manufacturing a semiconductor device using an adhesive sheet having an adhesive layer and a non-adhesive base material containing expandable particles,
the method comprises the following steps (1) to (4),
step (1): a step of adhering the frame member having the opening formed thereon to the adhesive surface of the adhesive layer;
Step (2): a step of placing a semiconductor chip on a part of an adhesive surface of the adhesive layer exposed at the opening of the frame member;
step (3): a step of covering a peripheral portion of the semiconductor chip, the frame member, and the adhesive surface of the adhesive layer with a sealing material, and curing the sealing material to obtain a cured sealing body in which the semiconductor chip is sealed with the cured sealing material;
step (4): and a step of expanding the expandable particles and peeling the adhesive sheet from the cured sealing body.
[2] The method for manufacturing a semiconductor device according to [1], further comprising the following step (5),
step (5): and forming a rewiring layer on the cured sealing body after the adhesive sheet is peeled off.
[3] The method for manufacturing a semiconductor device according to the above [1] or [2], wherein the expandable particles are thermally expandable particles, and the step (4) is a step of expanding the thermally expandable particles by heating the adhesive sheet and peeling the adhesive sheet from the cured sealing body
[4] The method for manufacturing a semiconductor device according to [3], wherein the expansion initiation temperature (t) of the thermally expandable particles is 120 to 250 ℃.
[5] The method for manufacturing a semiconductor device according to [4], wherein the substrate satisfies the following requirements (1) to (2),
element (1): the storage modulus E' (100) of the substrate at 100 ℃ is 2.0X10 5 Pa or more;
element (2): the substrate has a storage modulus E' (t) of 1.0X10 at the expansion initiation temperature (t) of the thermally expandable particles 7 Pa or below.
[6] The method for manufacturing a semiconductor device according to any one of [1] to [5], wherein the expandable particles have an average particle diameter of 3 to 100 μm before expansion at 23 ℃.
[7]Above [1]]～[6]The method for manufacturing a semiconductor device according to any one of claims, wherein the adhesive layer has a shear modulus G' (23) at 23 ℃ of 1.0×10 4 ～1.0×10 8 Pa。
[8] The method for manufacturing a semiconductor device according to any one of [1] to [7], wherein a ratio of a thickness of the base material to a thickness of the adhesive layer (base material/adhesive layer) is 0.2 or more at 23 ℃.
[9] The method for manufacturing a semiconductor device according to any one of [1] to [8], wherein the thickness of the base material is 10 to 1000 μm and the thickness of the adhesive layer is 1 to 60 μm at 23 ℃.
[10] The method for manufacturing a semiconductor device according to any one of [1] to [9], wherein the probe adhesion value of the substrate surface is less than 50mN/5 mm. Phi.
[11] An adhesive sheet used in the method for producing a semiconductor device according to any one of [1] to [10], wherein the adhesive sheet has an adhesive layer and a non-adhesive base material containing expandable particles.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide a method for manufacturing a semiconductor device, which can suppress positional displacement of a semiconductor chip in a manufacturing process of a fan-out package, is excellent in productivity, and is excellent in flatness of a re-wiring layer formation surface of the obtained semiconductor device, and an adhesive sheet usable in the manufacturing method.
Drawings
Fig. 1 is a cross-sectional view of an adhesive sheet showing an example of the structure of the adhesive sheet according to the present embodiment.
Fig. 2 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment.
Fig. 3 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment, next to fig. 2.
Fig. 4 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment, next to fig. 3.
Symbol description
10. Double-sided adhesive sheet
11. Substrate material
11a surface
12. Adhesive layer
12a adhesive surface
13. Release material
20. Frame component
21. An opening part
30. Peripheral portion of semiconductor chip in adhesive surface of adhesive layer
40. Sealing material
41. Cured sealing material
50. Cured seal
50a face
61. 1 st insulating layer
62. 2 nd insulating layer
70. Rewiring
70A external electrode pad
80. External terminal electrode
90. Suction table
91. Suction hole
100. Semiconductor device with a semiconductor device having a plurality of semiconductor chips
CP semiconductor chip
W1 circuit surface
W2 circuit
W3 internal terminal electrode
Detailed Description
In the present invention, the term "active ingredient" refers to a component other than a diluting solvent among components contained in the composition to be subjected to the composition.
The weight average molecular weight (Mw) is a value converted to standard polystyrene measured by Gel Permeation Chromatography (GPC), and is specifically measured by the method described in examples.
In the present invention, for example, "(meth) acrylic" means both "acrylic" and "methacrylic", and other similar terms are the same.
The lower limit value and the upper limit value described in stages may be independently combined with each other in a preferable numerical range (for example, a range of content or the like). For example, according to the description of "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit value (10)" and the "more preferable upper limit value (60)" may be combined to obtain "10 to 60".
[ method for manufacturing semiconductor device ]
The method for manufacturing a semiconductor device according to the present embodiment is a method for manufacturing a semiconductor device using an adhesive sheet having an adhesive layer and a non-adhesive base material containing expandable particles, and includes the following steps (1) to (4).
Step (1): a step of adhering the frame member having the opening to the adhesive surface of the adhesive layer
Step (2): a step of placing a semiconductor chip on a part of the adhesive surface of the adhesive layer exposed at the opening of the frame member
Step (3): a step of covering the peripheral portion of the semiconductor chip in the bonding surface of the frame member, the adhesive layer, and the semiconductor chip with a sealing material, and curing the sealing material to obtain a cured sealing body in which the semiconductor chip is sealed with the cured sealing material
Step (4): expanding the expandable particles and peeling the adhesive sheet from the cured sealing body
Hereinafter, an adhesive sheet usable in the method for manufacturing a semiconductor device according to the present embodiment will be described first, and then each manufacturing process including steps (1) to (4) will be described.
< adhesive sheet >
The pressure-sensitive adhesive sheet of the present embodiment is not particularly limited as long as it has a pressure-sensitive adhesive layer and a non-pressure-sensitive adhesive base material containing expandable particles (hereinafter also referred to as "expandable base material").
The adhesive sheet may take various shapes such as a sheet, a tape, a label, and the like.
(Structure of adhesive sheet)
Fig. 1 (a) is a cross-sectional view of an adhesive sheet 10 according to the present embodiment.
As shown in fig. 1 (a), the pressure-sensitive adhesive sheet 10 of the present embodiment has a pressure-sensitive adhesive layer 12 on a base material 11.
As in the adhesive sheet 10a shown in fig. 1 (B), the adhesive sheet of the present embodiment may have a structure in which the release material 13 is further provided on the adhesive surface 12a of the adhesive layer 12. The release material 13 can be suitably peeled off and removed when the adhesive sheet 10a is used in the method for manufacturing a semiconductor device according to the present embodiment.
The expandable base material, the pressure-sensitive adhesive layer, and the release material used as needed in the pressure-sensitive adhesive sheet of the present embodiment will be described in order.
(intumescent base material)
The expandable substrate is a non-adhesive substrate containing expandable particles.
In general, the thermally expandable adhesive layer of the adhesive sheet described in patent document 2 contains sufficient expandable particles in addition to an adhesive having a low elastic modulus as a main component, and therefore a certain thickness is required. The following disadvantages therefore occur: the semiconductor chip is displaced between the mounting step and the sealing step, and the semiconductor chip is immersed in the adhesive sheet side, so that the rewiring layer formation surface cannot be flattened.
On the other hand, in the pressure-sensitive adhesive sheet of the present embodiment, since the expandable particles contain a non-adhesive resin having a high elastic modulus, the degree of freedom in design such as thickness adjustment of the pressure-sensitive adhesive layer on which the semiconductor chip is placed, control of the adhesive force, the viscoelastic modulus, and the like is improved. This can prevent the semiconductor chip from being displaced and from sinking into the double-sided adhesive sheet, thereby forming a rewiring layer forming surface excellent in flatness.
In addition, in the case of using the adhesive sheet of the present embodiment, since the semiconductor chip is placed on the adhesive surface of the adhesive layer, the expandable base material does not directly come into surface contact with the rewiring layer. This can prevent the residue from the expandable particles and a part of the adhesive layer after the substantial deformation from adhering to the rewiring layer formation surface, and the uneven shape formed on the thermally expandable adhesive layer is transferred to the rewiring layer formation surface, thereby reducing the smoothness, and providing a rewiring layer formation surface excellent in cleanliness and smoothness.
The thickness of the expandable substrate is preferably 10 to 1000. Mu.m, more preferably 20 to 500. Mu.m, still more preferably 25 to 400. Mu.m, still more preferably 30 to 300. Mu.m.
In the present specification, the thickness of the expandable base material is a value measured by the method described in examples.
The expandable substrate of the adhesive sheet is a non-adhesive substrate.
In the present invention, the judgment as to whether or not the substrate is non-adhesive is performed by: as to the surface of the target substrate, the substrate was judged as a "non-adhesive substrate" as long as the probe tack value measured in accordance with JIS Z0237:1991 was less than 50mN/5 mm. Phi.
Here, the probe tack value of the surface of the expandable substrate used in the present embodiment is usually less than 50mN/5 mm. Phi., preferably less than 30mN/5 mm. Phi., more preferably less than 10mN/5 mm. Phi., still more preferably less than 5mN/5 mm. Phi.
In the present specification, a specific method for measuring the probe tack value of the surface of the expandable substrate was performed according to the method described in examples.
The expandable base material of the pressure-sensitive adhesive sheet of the present embodiment contains a resin and expandable particles, and may contain a base material additive as necessary, within a range that does not impair the effects of the present invention.
The expandable base material may be formed of a resin composition (y) containing a resin and expandable particles.
The components contained in the resin composition (y) as the expandable base material forming material will be described below.
< resin >)
The resin contained in the resin composition (y) is not particularly limited as long as the expandable base material is a non-adhesive resin, and may be a non-adhesive resin or an adhesive resin.
That is, even if the resin contained in the resin composition (y) is an adhesive resin, the adhesive resin and the polymerizable compound are polymerized in the process of forming the expandable base material from the resin composition (y), and the obtained resin is a non-adhesive resin, and the expandable base material containing the resin is non-adhesive.
The weight average molecular weight (Mw) of the resin contained in the resin composition (y) is preferably 1000 to 100 ten thousand, more preferably 1000 to 70 ten thousand, and even more preferably 1000 to 50 ten thousand.
In the case where the resin is a copolymer having 2 or more structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer and a graft copolymer.
The content of the resin is preferably 50 to 99% by mass, more preferably 60 to 95% by mass, still more preferably 65 to 90% by mass, and still more preferably 70 to 85% by mass, relative to the total amount (100% by mass) of the active ingredient of the resin composition (y).
The resin contained in the resin composition (y) preferably contains 1 or more kinds selected from the group consisting of acrylic urethane resins and olefin resins.
The acrylic urethane resin is preferably the following resin (U1).
An acrylic urethane resin (U1) obtained by polymerizing a Urethane Prepolymer (UP) with a vinyl compound containing a (meth) acrylic ester.
[ acrylic urethane resin (U1) ]
As the Urethane Prepolymer (UP) forming the main chain of the acrylic urethane resin (U1), reactants of a polyol and a polyisocyanate are exemplified.
The Urethane Prepolymer (UP) is preferably obtained by further performing a chain extension reaction using a chain extender.
Examples of the polyol to be a raw material of the Urethane Prepolymer (UP) include: alkylene polyols, ether polyols, ester amide polyols, ester/ether polyols, carbonate polyols, and the like.
These polyols may be used alone or in combination of 2 or more.
The polyhydric alcohol used in the present embodiment is preferably a diol, more preferably an ester diol, an alkylene diol, and a carbonate diol, and still more preferably an ester diol and a carbonate diol.
Examples of the ester diol include: alkanediols such as 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol and 1, 6-hexanediol; polycondensates of one or more selected from diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and the like, and one or more selected from dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4-diphenyldicarboxylic acid, diphenylmethane-4, 4' -dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, chlorobridge acid, maleic acid, fumaric acid, itaconic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid and anhydrides thereof.
Specifically, there may be mentioned: polyethylene glycol adipate glycol, polybutylene glycol adipate glycol, polyhexamethylene glycol isophthalate glycol, polytetramethylene glycol adipate glycol, polyethylene glycol propylene glycol adipate glycol, polybutylene glycol hexamethylene glycol adipate glycol, polyethylene glycol adipate glycol, polytetramethylene ether glycol adipate glycol, poly (3-methylpentanedioate) glycol, polyethylene azelate glycol, polyethylene sebacate glycol, polybutylene azelate glycol, polybutylene sebacate glycol, and polyethylene glycol terephthalate.
Examples of the alkylene glycol include: alkanediols such as 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, neopentyl glycol and 1, 6-hexanediol; alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and the like; polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; polyoxyalkylene glycols such as polytetramethylene glycol; etc.
Examples of the carbonate diol include: 1, 4-butanediol carbonate diol, 1, 5-pentanediol carbonate diol, 1, 6-hexanediol carbonate diol, 1, 2-propanediol carbonate diol, 1, 3-propanediol carbonate diol, 2-dimethylpropanediol carbonate diol, 1, 7-heptanediol carbonate diol, 1, 8-octanediol carbonate diol, 1, 4-cyclohexanediol carbonate diol, and the like.
Examples of the polyisocyanate used as a raw material of the Urethane Prepolymer (UP) include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates.
These polyisocyanates may be used alone or in combination of 2 or more.
These polyisocyanates may be trimethylolpropane adduct type modified products, biuret type modified products obtained by reacting with water, or isocyanurate type modified products containing an isocyanurate ring.
Among these, the polyisocyanate used in one embodiment of the present invention is preferably a diisocyanate, and more preferably at least one selected from the group consisting of 4,4' -diphenylmethane diisocyanate (MDI), 2, 4-toluene diisocyanate (2, 4-TDI), 2, 6-toluene diisocyanate (2, 6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate.
Examples of the alicyclic diisocyanate include: 3-isocyanatomethyl-3, 5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 1, 3-cyclopentane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, methyl-2, 6-cyclohexane diisocyanate, and the like, isophorone diisocyanate (IPDI) being preferred.
In the present embodiment, the Urethane Prepolymer (UP) forming the main chain of the acrylic urethane resin (U1) is a reactant of a diol and a diisocyanate, and is preferably a linear urethane prepolymer having an ethylenically unsaturated group at both ends.
As a method for introducing an ethylenically unsaturated group at both ends of the linear urethane prepolymer, there can be mentioned: a method of reacting a terminal NCO group of a linear urethane prepolymer formed by reacting a diol with a diisocyanate compound with a hydroxyalkyl (meth) acrylate.
As the hydroxyalkyl (meth) acrylate, there may be mentioned, for example: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and the like.
The branched vinyl compound forming the urethane acrylate resin (U1) contains at least (meth) acrylate.
The (meth) acrylic acid ester is preferably 1 or more selected from the group consisting of alkyl (meth) acrylates and hydroxyalkyl (meth) acrylates, and more preferably the alkyl (meth) acrylates and the hydroxyalkyl (meth) acrylates are used in combination.
When the alkyl (meth) acrylate and the hydroxyalkyl (meth) acrylate are used in combination, the blending ratio of the hydroxyalkyl (meth) acrylate is preferably 0.1 to 100 parts by mass, more preferably 0.5 to 30 parts by mass, still more preferably 1.0 to 20 parts by mass, and still more preferably 1.5 to 10 parts by mass, relative to 100 parts by mass of the alkyl (meth) acrylate.
The number of carbon atoms of the alkyl group of the alkyl (meth) acrylate is preferably 1 to 24, more preferably 1 to 12, still more preferably 1 to 8, and still more preferably 1 to 3.
Further, as the hydroxyalkyl (meth) acrylate, there may be mentioned the same one as that used for introducing an ethylenically unsaturated group at both ends of the above-mentioned linear urethane prepolymer.
Examples of the vinyl compound other than the (meth) acrylate include: aromatic hydrocarbon vinyl compounds such as styrene, α -methylstyrene, and vinyltoluene; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; polar group-containing monomers such as vinyl acetate, vinyl propionate, (meth) acrylonitrile, N-vinylpyrrolidone, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, and (meth) acrylamide; etc.
These vinyl compounds may be used alone or in combination of 2 or more.
The content of the (meth) acrylic acid ester in the vinyl compound is preferably 40 to 100 mass%, more preferably 65 to 100 mass%, even more preferably 80 to 100 mass%, and still more preferably 90 to 100 mass% based on the total amount (100 mass%) of the vinyl compound.
The total content of the alkyl (meth) acrylate and the hydroxyalkyl (meth) acrylate in the vinyl compound is preferably 40 to 100% by mass, more preferably 65 to 100% by mass, still more preferably 80 to 100% by mass, and still more preferably 90 to 100% by mass, based on the total amount (100% by mass) of the vinyl compound.
The acrylic urethane resin (U1) used in the present embodiment can be obtained by mixing a Urethane Prepolymer (UP) with a vinyl compound containing a (meth) acrylate and polymerizing both.
In this polymerization, it is preferable to further add a radical initiator.
In the acrylic urethane resin (U1) used in the present embodiment, the content ratio of the structural unit (U11) derived from the Urethane Prepolymer (UP) to the structural unit (U12) derived from the vinyl compound) [ U11)/(U12) ] is preferably 10/90 to 80/20, more preferably 20/80 to 70/30, still more preferably 30/70 to 60/40, and still more preferably 35/65 to 55/45 in terms of mass ratio.
[ olefin-based resin ]
As the resin contained in the resin composition (y), a suitable olefin-based resin is a polymer having at least a structural unit derived from an olefin monomer.
The olefin monomer is preferably an α -olefin having 2 to 8 carbon atoms, and specific examples thereof include: ethylene, propylene, butene, isobutylene, 1-hexene, and the like.
Among them, ethylene and propylene are preferable.
Specific examples of the olefin-based resin include: ultra low density polyethylene (VLDPE, density: 880 kg/m) 3 Above and below 910kg/m 3 ) Low density polyethylene (LDPE, density: 910kg/m 3 Above and below 915kg/m 3 ) Medium density polyethylene (MDPE, density: 915kg/m 3 Above and below 942kg/m 3 ) High density polyethylene (HDPE, density: 942kg/m 3 Above), linear low density polyethylene and other polyethylene resins; polypropylene resin (PP); polybutene resin (PB); ethylene-propyleneA copolymer; olefinic elastomers (TPOs); poly (4-methyl-1-pentene) (PMP); ethylene vinyl acetate copolymer (EVA); ethylene vinyl alcohol copolymer (EVOH); olefin terpolymers such as ethylene-propylene- (5-ethylidene-2-norbornene); etc.
In the present embodiment, the olefin-based resin may be a modified olefin-based resin obtained by further modifying at least one selected from the group consisting of acid modification, hydroxyl modification and acryl modification.
For example, as the acid-modified olefin-based resin obtained by acid-modifying an olefin-based resin, there may be mentioned a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or an acid anhydride thereof to the above-mentioned unmodified olefin-based resin.
Examples of the unsaturated carboxylic acid or anhydride thereof include: maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth) acrylic acid, maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dianhydride, tetrahydrophthalic anhydride, and the like.
The unsaturated carboxylic acid or its anhydride may be used alone or in combination of 2 or more.
The acryl-modified olefin-based resin obtained by modifying an olefin-based resin with an acryl group includes a modified polymer obtained by graft polymerizing an alkyl (meth) acrylate as a side chain to the above-mentioned unmodified olefin-based resin as a main chain.
The number of carbon atoms of the alkyl group of the alkyl (meth) acrylate is preferably 1 to 20, more preferably 1 to 16, and still more preferably 1 to 12.
Examples of the alkyl (meth) acrylate include those similar to those described below which can be selected as the monomer (a 1').
The hydroxyl-modified olefin-based resin obtained by modifying an olefin-based resin with a hydroxyl group includes a modified polymer obtained by graft-polymerizing a hydroxyl-containing compound to the above-mentioned unmodified olefin-based resin as a main chain.
Examples of the hydroxyl group-containing compound include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; unsaturated alcohols such as vinyl alcohol and allyl alcohol.
[ acrylic urethane resin and resin other than olefin resin ]
In the present embodiment, the resin composition (y) may contain a resin other than the acrylic urethane resin and the olefin resin within a range that does not impair the effects of the present invention.
Examples of such resins include: vinyl resins such as polyvinyl chloride, polyvinylidene chloride and polyvinyl alcohol; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; a polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; a polycarbonate; polyurethane which is not an acrylic urethane resin; polysulfone; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyether imide and polyimide; polyamide resin; an acrylic resin; fluororesin, and the like.
The content ratio of the resin other than the acrylic urethane resin and the olefin resin is preferably less than 30 parts by mass, more preferably less than 20 parts by mass, still more preferably less than 10 parts by mass, still more preferably less than 5 parts by mass, and still more preferably less than 1 part by mass relative to 100 parts by mass of the total amount of the resin contained in the resin composition (y).
< Expandable particles >)
The expandable particles are not particularly limited as long as they can expand themselves by an external stimulus to form irregularities in the adhesive layer and reduce the adhesion to the adherend.
Examples of the expandable particles include: the heat-expandable particles that expand by heating, energy ray-expandable particles that expand by irradiation with energy rays, and the like are preferable from the viewpoints of versatility and operability.
The thermally expandable particles are preferably particles having an expansion initiation temperature (t) adjusted to 120 to 250 ℃.
In the present specification, the expansion initiation temperature (t) of the thermally expandable particles is a value measured by the following method.
[ method for measuring expansion initiation temperature (t) of thermally-expansive particles ]
A sample was prepared by adding 0.5mg of thermally expandable particles to be measured to an aluminum cup having a diameter of 6.0mm (inner diameter of 5.65 mm) and a depth of 4.8mm, and putting an aluminum cap (diameter of 5.6mm and thickness of 0.1 mm) thereon.
The height of the sample was measured by applying a force of 0.01N to the sample from the upper part of the aluminum cap using a dynamic viscoelasticity measuring apparatus, and then, by applying a force of 0.01N to the sample using the indenter, the sample was heated from 20℃to 300℃at a heating rate of 10℃per minute in this state, and the displacement amount of the indenter in the vertical direction was measured, and the displacement initiation temperature in the forward direction was defined as the expansion initiation temperature (t).
The thermally expandable particles are preferably microcapsule foaming agents each comprising an outer shell made of a thermoplastic resin and an inner-shell component which is encapsulated in the outer shell and which is gasified when heated to a predetermined temperature.
Examples of the thermoplastic resin constituting the shell of the microcapsule foaming agent include: vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, polysulfone, and the like.
Examples of the inner package component that is enclosed in the outer shell include: propane, butane, pentane, hexane, heptane, octane, nonane, decane, isobutane, isopentane, isohexane, isoheptane, isooctane, isononane, isodecane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isododecane, cyclodecane, hexylcyclohexane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, isotridecane, 4-methyldodecane, isotetradecane, isopentadecane, isohexadecane, 2,4, 6, 8-heptamethylnonane, isoheptadecane, isostearane, 2,6,10, 14-tetramethylpentadecane, tridecane, heptylcyclohexane, n-octylcyclohexane, cyclopentadecane, nonylcyclohexane, decylcyclohexane, pentadecane, hexadecylcyclohexane, heptadecane, octadecylcyclohexane, and the like.
These inner package components may be used alone or in combination of 2 or more.
The expansion initiation temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of the inner package component.
The volume maximum expansion ratio of the thermally expandable particles used in the present embodiment is preferably 1.5 to 100 times, more preferably 2 to 80 times, further preferably 2.5 to 60 times, and still more preferably 3 to 40 times when the particles are heated to a temperature equal to or higher than the thermal expansion initiation temperature (t).
The average particle diameter of the expandable particles before expansion at 23℃used in the present embodiment is preferably 3 to 100. Mu.m, more preferably 4 to 70. Mu.m, still more preferably 6 to 60. Mu.m, still more preferably 10 to 50. Mu.m.
The average particle diameter of the expandable particles before expansion means the volume median particle diameter (D 50 ) The cumulative volume frequency calculated from the particle size of the expandable particles before expansion, which is measured by a laser diffraction particle size distribution measuring apparatus (for example, manufactured by Malvern corporation, product name "Mastersizer 3000"), is 50% of the particle size.
As the expandable particles used in the present embodiment, the particle diameter (D) of 90% of the expandable particles before expansion at 23 ℃ 90 ) Preferably 10 to 150. Mu.m, more preferably 20 to 100. Mu.m, still more preferably 25 to 90. Mu.m, still more preferably 30 to 80. Mu.m.
The expandable particles had a particle diameter of 90% before expansion (D 90 ) Using a laser diffraction type particle size distribution measuring apparatus (e.gIn the particle distribution of the expandable particles before expansion, which was measured by Malvern corporation under the product name "Mastersizer 3000"), the cumulative volume frequency calculated from the particle diameter of the expandable particles before expansion was 90% of the particle diameter.
The content of the expandable particles is preferably 1 to 40 mass%, more preferably 5 to 35 mass%, still more preferably 10 to 30 mass%, and still more preferably 15 to 25 mass% relative to the total amount (100 mass%) of the active ingredient of the resin composition (y).
Additive for substrate >
The resin composition (y) used in the present embodiment may further contain a base material additive contained in a base material of a general adhesive sheet within a range that does not impair the effect of the present invention.
Examples of such additives for a substrate include: ultraviolet light absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, colorants, and the like.
These additives for a substrate may be used alone or in combination of 2 or more.
When these base material additives are contained, the content of each base material additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, based on 100 parts by mass of the resin in the resin composition (y).
Solvent-free resin composition (y 1) >, and process for producing the same
One embodiment of the resin composition (y) used in the present embodiment is a solvent-free resin composition (y 1) in which an oligomer having an ethylenically unsaturated group and having a weight average molecular weight (Mw) of 50000 or less, an energy ray polymerizable monomer, and the above-described expandable particles are blended, and in which no solvent is blended.
In the solvent-free resin composition (y 1), the energy ray polymerizable monomer contributes to improvement of the plasticity of the oligomer although the solvent is not blended.
The expandable substrate can be obtained by irradiating a coating film formed from the solvent-free resin composition (y 1) with an energy beam.
The type, shape, and amount (content) of the expandable particles blended in the solvent-free resin composition (y 1) are as described above.
The weight average molecular weight (Mw) of the oligomer contained in the solvent-free resin composition (y 1) is 50000 or less, preferably 1000 to 50000, more preferably 2000 to 40000, still more preferably 3000 to 35000, still more preferably 4000 to 30000.
The oligomer may be any oligomer having an ethylenically unsaturated group, and the Urethane Prepolymer (UP) is preferable, as long as the weight average molecular weight (Mw) of the resin contained in the resin composition (y) is 50000 or less.
As the oligomer, a modified olefin resin having an ethylenically unsaturated group or the like may be used.
The total content of the oligomer and the energy ray polymerizable monomer in the solvent-free resin composition (y 1) is preferably 50 to 99 mass%, more preferably 60 to 95 mass%, even more preferably 65 to 90 mass%, and even more preferably 70 to 85 mass%, based on the total amount (100 mass%) of the solvent-free resin composition (y 1).
Examples of the energy ray polymerizable monomer include: alicyclic polymerizable compounds such as isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, adamantyl (meth) acrylate, and tricyclodecyl acrylate; aromatic polymerizable compounds such as phenylpropyl acrylate, benzyl acrylate, and phenol ethylene oxide-modified acrylate; and heterocyclic polymerizable compounds such as tetrahydrofurfuryl (meth) acrylate, morpholinyl acrylate, N-vinylpyrrolidone and N-vinylcaprolactam.
These energy ray polymerizable monomers may be used alone or in combination of 2 or more.
In the solvent-free resin composition (y 1), the content ratio of the oligomer to the energy ray-polymerizable monomer (the oligomer/the energy ray-polymerizable monomer) is preferably 20/80 to 90/10, more preferably 30/70 to 85/15, and even more preferably 35/65 to 80/20 in terms of mass ratio.
In the present embodiment, the solvent-free resin composition (y 1) is preferably further blended with a photopolymerization initiator.
By containing the photopolymerization initiator, the curing reaction can be sufficiently performed by irradiation with an energy ray having a relatively low energy.
Examples of the photopolymerization initiator include: 1-hydroxycyclohexyl phenyl ketone, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzyl phenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, and the like.
These photopolymerization initiators may be used alone or in combination of 2 or more.
The amount of the photopolymerization initiator to be blended is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 4 parts by mass, and even more preferably 0.02 to 3 parts by mass, based on the total amount (100 parts by mass) of the oligomer and the energy ray polymerizable monomer.
< storage modulus of substrate >)
The storage modulus E' (23) of the expandable base material of the pressure-sensitive adhesive sheet of the present embodiment at 23 ℃ is preferably 1.0×10 6 Pa or more, more preferably 5.0X10 6 ～5.0×10 12 Pa, more preferably 1.0X10 7 ～1.0×10 12 Pa, still more preferably 5.0X10 7 ～1.0×10 11 Pa, still more preferably 1.0X10 8 ～1.0×10 10 Pa. By using the expandable base material having the storage modulus E' (23) within the above range, positional displacement of the semiconductor chip can be prevented, and the semiconductor chip can be prevented from sinking into the adhesive layer.
For example, the semiconductor chip is placed in such a manner that its circuit face is covered with the adhesive surface of the adhesive layer. The semiconductor chip may be mounted by a known device such as a flip chip bonder or a die bonder. In the above-described steps, when the semiconductor chip is placed on the adhesive layer of the adhesive sheet using the flip chip bonder or the die bonder, a force pressing the semiconductor chip into the thickness direction of the adhesive sheet is applied, and therefore, there is a possibility that the semiconductor chip excessively sinks into the thickness direction side of the adhesive layer. In addition, when the semiconductor chip is placed on the adhesive sheet using the flip chip bonder or the die bonder, a force for moving the semiconductor chip in the horizontal direction of the adhesive sheet is applied, and therefore, there is also a possibility that the semiconductor chip is displaced in the horizontal direction of the adhesive layer. However, these problems can also be solved by using an expandable substrate that satisfies the storage modulus E' (23) described above.
In the present specification, the storage modulus E' of the expandable substrate at a given temperature is a value measured by the method described in examples.
The expandable base material of the pressure-sensitive adhesive sheet of the present embodiment preferably has a storage modulus satisfying the following requirement (1).
Element (1): the storage modulus E' (100) of the expandable base material at 100 ℃ is 2.0X10 5 Pa or more.
Since the expandable base material satisfying the requirement (1) can appropriately suppress the flow of the expandable particles even in the temperature environment of the sealing step in the FOWLP and FOPLP production process, the adhesive surface of the adhesive layer provided on the expandable base material is less likely to be deformed. As a result, positional displacement of the semiconductor chip can be prevented, and the semiconductor chip can be prevented from sinking into the adhesive layer.
From the above point of view, the storage modulus E' (100) of the expandable base material is more preferably 4.0X10 5 Pa or more, more preferably 6.0X10 5 Pa or more, and more preferably 8.0X10 5 Pa or more, more preferably 1.0X10 6 Pa or more.
In addition, from the viewpoint of effectively suppressing positional displacement of the semiconductor chip in the sealing step, the storage modulus E' (100) of the expandable base material is preferably 1.0×10 12 Pa or less, more preferably 1.0X10 11 Pa or less, more preferably 1.0X10 10 Pa or less, and more preferably 1.0X10 9 Pa to PaAnd (3) downwards.
In the case where the expandable base material included in the pressure-sensitive adhesive sheet of the present embodiment contains thermally expandable particles as the expandable particles, it is preferable that the storage modulus satisfies the following requirement (2).
Element (2): the expandable base material has a storage modulus E' (t) of 1.0X10 at the expansion initiation temperature (t) of the thermally expandable particles 7 Pa or below.
By having an expandable base material satisfying the requirement (2), the expandable base material is easily deformed following the volume expansion of the thermally expandable particles at a temperature at which the thermally expandable particles expand, and irregularities are easily formed on the adhesive surface of the adhesive layer. This makes it possible to peel off the object with a small external force.
From the above point of view, the storage modulus E' (t) of the expandable base material is more preferably 9.0X10 6 Pa or less, more preferably 8.0X10 6 Pa or less, and more preferably 6.0X10 6 Pa or less, and still more preferably 4.0X10 6 Pa or below.
In addition, from the viewpoints of suppressing the flow of the thermally expandable particles after expansion, improving the shape retention of irregularities formed on the adhesive surface of the adhesive layer, and further improving the peelability, the storage modulus E' (t) of the expandable base material is preferably 1.0×10 3 Pa or more, more preferably 1.0X10 4 Pa or more, more preferably 1.0X10 5 Pa or more.
(adhesive layer)
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment may contain a pressure-sensitive adhesive resin, and may contain, if necessary, an adhesive additive such as a crosslinking agent, a tackifier, a polymerizable compound, and a polymerization initiator.
The pressure-sensitive adhesive layer is preferably a non-swelling pressure-sensitive adhesive layer from the viewpoint of preventing the semiconductor chip placed therein from sinking into the pressure-sensitive adhesive layer by heating in the sealing step.
In the pressure-sensitive adhesive sheet of the present embodiment, the pressure-sensitive adhesive force at 23℃of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer before expansion of the expandable particles is preferably 0.1 to 10.0N/25mm, more preferably 0.2 to 8.0N/25mm, still more preferably 0.4 to 6.0N/25mm, and still more preferably 0.5 to 4.0N/25mm.
When the adhesive force is 0.1N/25mm or more, the semiconductor chip can be sufficiently fixed to a degree that positional displacement of the semiconductor chip in the sealing step can be prevented.
On the other hand, when the adhesive force is 10.0N/25mm or less, the adhesive force can be easily peeled off from the adherend with a small external force.
The adhesive force mentioned above is a value measured by the method described in examples.
In the pressure-sensitive adhesive sheet of the present embodiment, the shear modulus G' (23) of the pressure-sensitive adhesive layer at 23 ℃ is preferably 1.0×10 4 ～1.0×10 8 Pa, more preferably 5.0X10 4 ～5.0×10 7 Pa, more preferably 1.0X10 5 ～1.0×10 7 Pa。
In the case of an adhesive sheet having a plurality of adhesive layers, the shear modulus G '(23) of the adhesive layer to which the semiconductor chip is attached is preferably within the above range, and the shear modulus G' (23) of the entire adhesive layer on the side of the expandable base material to which the semiconductor chip is attached is preferably within the above range.
The shear modulus G' (23) of the adhesive layer was 1.0X10 4 When Pa is equal to or greater, positional displacement of the semiconductor chip can be prevented, and the semiconductor chip can be prevented from sinking into the adhesive layer.
On the other hand, the shear modulus G' (23) of the adhesive layer was 1.0X10 8 When Pa or less, the surface of the pressure-sensitive adhesive layer is easily roughened by expansion of the expandable particles in the expandable base material, and as a result, the pressure-sensitive adhesive layer can be easily peeled off with a small force.
In the present specification, the shear modulus G' (23) of the adhesive layer refers to a value measured by the method described in examples.
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment preferably has a thickness of 1 to 60 μm, more preferably 2 to 50 μm, still more preferably 3 to 40 μm, still more preferably 5 to 30 μm, from the viewpoint of exhibiting excellent pressure-sensitive adhesive force and from the viewpoint of easily forming irregularities on the surface of the pressure-sensitive adhesive layer formed by expansion of expandable particles in the expandable base material.
The pressure-sensitive adhesive sheet of the present embodiment is preferably 0.2 or more, more preferably 0.5 or more, still more preferably 1.0 or more, still more preferably 5.0 or more, from the viewpoint of flattening the rewiring layer formation surface and preventing positional displacement of the semiconductor chip, as a ratio of the thickness of the expandable substrate to the thickness of the pressure-sensitive adhesive layer (expandable substrate/pressure-sensitive adhesive layer) at 23 ℃.
The thickness of the adhesive layer refers to a value measured by the method described in examples.
The adhesive layer may be formed of an adhesive composition including an adhesive resin.
Hereinafter, each component contained in the adhesive composition as a material for forming the adhesive layer will be described.
< adhesive resin >)
The adhesive resin used in the present embodiment is preferably a polymer having adhesive properties alone and a weight average molecular weight (Mw) of 1 ten thousand or more.
The weight average molecular weight (Mw) of the adhesive resin used in the present embodiment is more preferably 1 to 200 tens of thousands, still more preferably 2 to 150 tens of thousands, and still more preferably 3 to 100 tens of thousands, from the viewpoint of improving the adhesive force.
Examples of the adhesive resin include: rubber-based resins such as acrylic resins, urethane resins and polyisobutylene resins, polyester resins, olefin resins, silicone resins and polyvinyl ether resins.
These adhesive resins may be used alone or in combination of 2 or more.
In the case where these adhesive resins are copolymers having 2 or more structural units, the form of the copolymer is not particularly limited, and may be any of a block copolymer, a random copolymer and a graft copolymer.
The adhesive resin used in the present embodiment may be an energy ray curable adhesive resin in which a polymerizable functional group is introduced into a side chain of the adhesive resin.
Examples of the polymerizable functional group include a (meth) acryloyl group and a vinyl group.
The energy lines include: ultraviolet rays, electron beams, and the like, and ultraviolet rays are preferable.
The content of the adhesive resin is preferably 30 to 99.99 mass%, more preferably 40 to 99.95 mass%, even more preferably 50 to 99.90 mass%, still more preferably 55 to 99.80 mass%, and still more preferably 60 to 99.50 mass%, relative to the total amount (100 mass%) of the active ingredients of the adhesive composition.
In the following description of the present specification, the "content of each component relative to the total amount of the active components of the adhesive composition" means the same as "content of each component in the adhesive layer formed from the adhesive composition".
In the present embodiment, the adhesive resin preferably contains an acrylic resin from the viewpoint of exhibiting excellent adhesive force and from the viewpoint of easily forming irregularities on the surface of the formed adhesive layer by expansion of the expandable particles in the expandable base material due to the heat treatment.
The content of the acrylic resin in the adhesive resin is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 70 to 100 mass%, and even more preferably 85 to 100 mass% with respect to the total amount (100 mass%) of the adhesive resin contained in the adhesive composition.
[ acrylic resin ]
In the present embodiment, examples of the acrylic resin that can be used as the adhesive resin include a polymer containing a structural unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group, a polymer containing a structural unit derived from a (meth) acrylate having a cyclic structure, and the like.
The weight average molecular weight (Mw) of the acrylic resin is preferably 10 to 150 tens of thousands, more preferably 20 to 130 tens of thousands, still more preferably 35 to 120 tens of thousands, still more preferably 50 to 110 tens of thousands.
The acrylic resin is more preferably an acrylic copolymer (A1), and the acrylic copolymer (A1) has a structural unit (A1) derived from an alkyl (meth) acrylate (A1 ') (hereinafter, also referred to as "monomer (A1')") and a structural unit (a 2) derived from a functional group-containing monomer (a 2 ') (hereinafter, also referred to as "monomer (a 2')").
The number of carbon atoms of the alkyl group in the monomer (a 1') is preferably 1 to 24, more preferably 1 to 12, still more preferably 2 to 10, still more preferably 4 to 8, from the viewpoint of improving the adhesive property.
The alkyl group contained in the monomer (a 1') may be a linear alkyl group or a branched alkyl group.
Examples of the monomer (a 1') include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, and the like.
These monomers (a 1') may be used alone or in combination of 2 or more.
As the monomer (a 1'), butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable.
The content of the structural unit (A1) is preferably 50 to 99.9 mass%, more preferably 60 to 99.0 mass%, still more preferably 70 to 97.0 mass%, and still more preferably 80 to 95.0 mass% relative to the total structural units (100 mass%) of the acrylic copolymer (A1).
Examples of the functional group of the monomer (a 2') include: hydroxyl, carboxyl, amino, epoxy, and the like.
That is, examples of the monomer (a 2') include: hydroxyl group-containing monomers, carboxyl group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like.
These monomers (a 2') may be used alone or in combination of 2 or more.
Among them, the monomer (a 2') is preferably a hydroxyl group-containing monomer or a carboxyl group-containing monomer.
Examples of the hydroxyl group-containing monomer include those similar to the above-mentioned hydroxyl group-containing compound.
Examples of the carboxyl group-containing monomer include: ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid, anhydrides thereof, 2- (acryloyloxy) ethyl succinate, 2-carboxyethyl (meth) acrylate, and the like.
The content of the structural unit (a 2) is preferably 0.1 to 40% by mass, more preferably 0.5 to 35% by mass, still more preferably 1.0 to 30% by mass, and still more preferably 3.0 to 25% by mass, relative to the total structural units (100% by mass) of the acrylic copolymer (A1).
The acrylic copolymer (A1) may further have a structural unit (a 3) derived from a monomer (a 3 ') other than the monomers (A1 ') and (a 2 ').
In the acrylic copolymer (A1), the content of the structural units (A1) and (a 2) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and still more preferably 95 to 100% by mass, based on the total structural units (100% by mass) of the acrylic copolymer (A1).
Examples of the monomer (a 3') include: olefins such as ethylene, propylene, and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene, and chloroprene; (meth) acrylic esters having a cyclic structure such as cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and imide (meth) acrylate; styrene, alpha-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, (meth) acrylamide, (meth) acrylonitrile, (meth) acryloylmorpholine, N-vinylpyrrolidone, and the like.
The acrylic copolymer (A1) may be an energy ray curable acrylic copolymer having a polymerizable functional group introduced into a side chain thereof.
The polymerizable functional group and the energy ray are as described above.
The polymerizable functional group can be introduced by reacting the acrylic copolymer having the above-mentioned structural units (a 1) and (a 2) with a compound having a substituent capable of bonding to the functional group of the structural unit (a 2) of the acrylic copolymer and a polymerizable functional group.
Examples of the above-mentioned compound include: (meth) acryloyloxyethyl isocyanate, (meth) acryloyloxyisocyanate, (meth) glycidyl acrylate, and the like.
< crosslinker >
In the present embodiment, when the adhesive composition contains the functional group-containing adhesive resin such as the acrylic copolymer (A1), it is preferable to further contain a crosslinking agent.
The crosslinking agent is a substance that reacts with the adhesive resin having a functional group and crosslinks the adhesive resins with each other using the functional group as a crosslinking origin.
Examples of the crosslinking agent include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, metal chelate-based crosslinking agents, and the like.
These crosslinking agents may be used alone or in combination of 2 or more.
Among these crosslinking agents, isocyanate-based crosslinking agents are preferable from the viewpoints of improving cohesive force and enhancing adhesive force, and from the viewpoints of easy availability.
The content of the crosslinking agent may be appropriately adjusted by the amount of the functional group of the adhesive resin, and is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 7 parts by mass, and even more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the adhesive resin having the functional group.
< tackifier >)
In the present embodiment, the adhesive composition preferably further contains a tackifier from the viewpoint of further improving the adhesive force.
In the present specification, the term "tackifier" refers to a component that aids in improving the adhesive force of the adhesive resin, and is an oligomer having a weight average molecular weight (Mw) of less than 1 ten thousand, and is distinguished from the adhesive resin.
The weight average molecular weight (Mw) of the thickener is preferably 400 to 10000, more preferably 500 to 8000, and even more preferably 800 to 5000.
Examples of the thickener include: rosin-based resins, terpene-based resins, styrene-based resins, C5-based petroleum resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperylene, and 1, 3-pentadiene produced by thermal cracking of naphtha, C9-based petroleum resins obtained by copolymerizing C9 fractions such as indene and vinyl toluene produced by thermal cracking of naphtha, hydrogenated resins obtained by hydrogenating these resins, and the like.
The softening point of the tackifier is preferably 60 to 170 ℃, more preferably 65 to 160 ℃, and still more preferably 70 to 150 ℃.
In the present specification, the "softening point" of the tackifier means a value measured in accordance with JIS K2531.
The tackifier may be used alone or in combination of 2 or more kinds different in softening point, structure and the like.
In the case of using 2 or more kinds of tackifiers, it is preferable that the weighted average of softening points of these kinds of tackifiers is in the above range.
The content of the tackifier is preferably 0.01 to 65 mass%, more preferably 0.05 to 55 mass%, still more preferably 0.1 to 50 mass%, still more preferably 0.5 to 45 mass%, and still more preferably 1.0 to 40 mass% relative to the total amount (100 mass%) of the active ingredients of the adhesive composition.
< photopolymerization initiator >)
In the present embodiment, when the adhesive composition contains an energy ray curable adhesive resin as the adhesive resin, it is preferable to further contain a photopolymerization initiator.
By preparing an adhesive composition containing an energy ray curable adhesive resin and a photopolymerization initiator, an adhesive layer formed from the adhesive composition can sufficiently undergo a curing reaction even by irradiation with a low-energy ray, and the adhesive force can be adjusted to a desired range.
The photopolymerization initiator may be the same as the initiator blended in the solvent-free resin composition (y 1).
The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the energy-ray-curable adhesive resin.
< additive for adhesive >)
In the present embodiment, the adhesive composition as the material for forming the adhesive layer may contain an additive for an adhesive used in a general adhesive in addition to the above-described additive within a range that does not impair the effects of the present invention.
Examples of such an additive for a binder include: antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, reaction inhibitors, reaction accelerators (catalysts), ultraviolet absorbers, and the like.
These additives for adhesives may be used alone or in combination of 2 or more.
When these additives for adhesives are contained, the content of each additive for adhesives is preferably 0.0001 to 20 parts by mass, more preferably 0.001 to 10 parts by mass, per 100 parts by mass of the adhesive resin.
The pressure-sensitive adhesive composition as a material for forming the pressure-sensitive adhesive layer may contain expandable particles within a range that does not impair the effects of the present invention.
However, as described above, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present embodiment is preferably a non-swelling pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive composition as a material for forming the pressure-sensitive adhesive layer preferably has a content of the expandable particles as small as possible.
The content of the expandable particles is preferably less than 5 mass%, more preferably less than 1 mass%, still more preferably less than 0.1 mass%, still more preferably less than 0.01 mass%, and particularly preferably less than 0.001 mass% relative to the total amount (100 mass%) of the active ingredients of the adhesive composition.
(Release Material)
As in the adhesive sheet 10a of fig. 1 (B), the adhesive sheet of the present embodiment may further have a release material on the adhesive surface of the adhesive layer.
As the release material, a release sheet subjected to a double-sided release treatment, a release sheet subjected to a single-sided release treatment, or the like can be used, and examples thereof include a release sheet having a release agent coated on a base material for a release material.
Examples of the base material for a release material include: paper such as full pulp paper, cellophane, kraft paper and the like; plastic films such as polyester resin films including polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, and olefin resin films including polypropylene resin and polyethylene resin; etc.
Examples of the stripping agent include: and rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long-chain alkyl resins, alkyd resins, and fluorine resins.
The thickness of the release material is not particularly limited, but is preferably 10 to 200. Mu.m, more preferably 25 to 170. Mu.m, and still more preferably 35 to 80. Mu.m.
[ method for producing pressure-sensitive adhesive sheet ]
The method for producing the pressure-sensitive adhesive sheet of the present embodiment is not particularly limited, and a production method (a) having the following steps (1 a) and (2 a) may be mentioned.
Step (1 a): and a step of forming a coating film by applying a resin composition (y) as a forming material of the expandable base material on the release treated surface of the release material, and drying or UV-curing the coating film.
Step (2 a): and a step of forming a coating film by applying an adhesive composition as a material for forming an adhesive layer on the surface of the formed expandable base material, and drying the coating film to form an adhesive layer.
Further, as another method for producing the pressure-sensitive adhesive sheet of the present embodiment, there is mentioned a method (b) comprising the following steps (1 b) to (3 b).
Step (1 b): and a step of forming a coating film by applying a resin composition (y) as a forming material of the expandable base material on the release treated surface of the release material, and drying or UV-curing the coating film.
Step (2 b): and a step of forming an adhesive layer by applying an adhesive composition as a material for forming the adhesive layer on the release treated surface of the release material to form a coating film and drying the coating film.
Step (3 b): and (2) bonding the surface of the expandable base material formed in the step (1 b) to the surface of the adhesive layer formed in the step (2 b).
In the above production methods (a) and (b), the resin composition (y) and the adhesive composition may be further mixed with a diluting solvent to prepare a solution.
Examples of the coating method include: spin coating, spray coating, bar coating, blade coating, roll coating, blade coating, die coating, gravure coating, and the like.
In the step (1 a) of the production method (a) and the step (1 b) of the production method (b), drying or UV irradiation of the expandable substrate formed from the coating film is preferably performed under conditions selected appropriately so that the expandable particles do not expand. For example, when the resin composition (y) containing the thermally expandable particles is dried to form an expandable base material, it is preferable to perform the drying under a condition that the drying temperature is lower than the expansion initiation temperature (t) of the thermally expandable particles.
< manufacturing Process of semiconductor device of the present embodiment >
Next, each step of the method for manufacturing a semiconductor device according to the present embodiment will be described.
The method for manufacturing a semiconductor device according to the present embodiment is a method for manufacturing a semiconductor device using the adhesive sheet, and includes the following steps (1) to (4).
Step (1): a step of adhering the frame member having the opening to the adhesive surface of the adhesive layer
Step (2): a step of placing a semiconductor chip on a part of an adhesive surface of the adhesive layer exposed at the opening of the frame member;
step (3): a step of coating the peripheral portion of the semiconductor chip on the bonding surface of the frame member and the adhesive layer with a sealing material, and curing the sealing material to obtain a cured sealing body in which the semiconductor chip is sealed with the cured sealing material
Step (4): expanding the expandable particles and peeling the adhesive sheet from the cured sealing body
Hereinafter, each step of the method for manufacturing a semiconductor device according to the present embodiment will be described with reference to the drawings.
(step (1))
Fig. 2 (a) shows a cross-sectional view illustrating the step (1), in which the frame member 20 having the opening 21 formed therein is adhered to the adhesive surface 12a of the adhesive layer 12 of the adhesive sheet 10.
In the case where the pressure-sensitive adhesive sheet 10 has the release material 13, the release material 13 is peeled off in advance.
The frame member 20 is formed in a lattice shape and has a plurality of openings 21.
The frame member 20 is preferably made of a material having heat resistance. The frame member 20 may be made of: metals such as copper, stainless steel, and 42 alloy; resins called engineering plastics such as polyimide resins, polyacetal resins, polyamide resins, polycarbonate resins, modified polyphenylene ether resins, and polybutylene terephthalate resins; glass epoxy resin and the like.
Thickness t of frame member 20 FR For example 100 μm to 3mm, preferably 100 μm to 1mm, more preferably 100 μm to 500 μm. Thickness t of frame member 20 FR When the thickness is 100 μm or more, warpage of the semiconductor package can be suppressed even when sealing a large area. Thickness t of frame member 20 FR When the thickness is 3mm or less, the productivity of the manufacturing process of the semiconductor device can be prevented from being lowered.
The opening 21 is a hole penetrating the front and rear surfaces of the frame member 20. The shape of the opening 21 is not particularly limited as long as the semiconductor chip CP can be accommodated in the frame. The depth of the hole of the opening 21 is not particularly limited as long as the semiconductor chip CP can be accommodated. In the present embodiment, a frame member having a plurality of openings 21 is used as the frame member 20, but a frame member having 1 opening may be used if the object of the present invention can be achieved.
The frame member 20 may preferably place a plurality of semiconductor chips CP on the adhesive surface 12a in a matrix-like state arranged in a plurality of rows and a plurality of columns with a certain interval therebetween.
(step (2))
Fig. 2 (B) is a cross-sectional view illustrating a step (2) in which the semiconductor chip CP is placed on a part of the adhesive surface 12a of the adhesive layer 12 exposed at the opening 21 of the frame member 20.
The semiconductor chip CP may be a conventionally known semiconductor chip CP. The semiconductor chip CP has an integrated circuit formed of circuit elements such as transistors, resistors, and capacitors on a circuit surface W1 thereof.
The semiconductor chip CP is placed, for example, such that the circuit surface W1 thereof is covered with the adhesive surface 12a. The semiconductor chip CP may be placed by a known device such as a flip chip bonder or a die bonder.
The layout, the number of layout, and the like of the semiconductor chips CP can be appropriately determined according to the targeted package form, the number of productions, and the like.
Here, the method of manufacturing a semiconductor device according to the present embodiment can be preferably used for a package in which the semiconductor chip CP is covered with the sealing material in a region larger than the chip size, such as FOWLP and FOPLP, and a rewiring layer is formed not only on the circuit surface W1 of the semiconductor chip CP but also on the surface region of the sealing material. Therefore, the semiconductor chip CP may be placed on a part of the adhesive surface 12a of the adhesive layer 12 exposed at the opening 21 of the frame member 20, and the semiconductor chip CP is more preferably placed at a certain interval from the frame member 20 surrounding the semiconductor chip CP. The interval between the semiconductor chip CP and the frame member 20 can be appropriately determined according to the form of the target package or the like.
By placing the semiconductor chip CP on a portion of the adhesive surface 12a of the adhesive layer 12 exposed at the opening 21 of the frame member 20, the peripheral portion 30 of the semiconductor chip CP can be formed in the adhesive surface 12a of the adhesive layer 12. In fig. 2 (B), the peripheral portion 30 of the semiconductor chip CP refers to the adhesive surface 12a of the adhesive layer 12 corresponding to the gap between the semiconductor chip CP and the frame member 20.
(step (3))
Fig. 2 (C) and (D) show cross-sectional views illustrating the step (3), in which the peripheral portion 30 of the semiconductor chip CP in the adhesive surface 12a of the adhesive layer 12, the frame member 20, and the semiconductor chip CP are covered with the sealing material 40, and the sealing material 40 is cured, to obtain a cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41.
Hereinafter, the step of coating the peripheral portion 30 of the semiconductor chip CP on the adhesive surface 12a of the frame member 20 and the adhesive layer 12 with the sealing material 40 is sometimes referred to as a "coating step", and the step of curing the sealing material 40 to obtain the cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41 is sometimes referred to as a "curing step".
As shown in fig. 2 (C), in the coating step, the peripheral portion 30 of the semiconductor chip CP in the adhesive surface 12a of the adhesive layer 12, the frame member 20, and the semiconductor chip CP are coated with the sealing material 40. The sealing material 40 covers the entire exposed surface of the semiconductor chip CP and the frame member 20, and fills the gap between the semiconductor chip CP and the frame member 20.
The sealing material 40 has a function of protecting the semiconductor chip CP and its accessory elements from the external environment.
The sealing material 40 is not particularly limited, and any material may be appropriately selected from materials currently used as semiconductor sealing materials.
The sealing material 40 is a material having curability from the viewpoints of mechanical strength, heat resistance, insulation, and the like, and examples thereof include: thermosetting resin compositions, energy ray-curable resin compositions, and the like.
In the present embodiment, a case where the sealing material 40 is a thermosetting resin composition will be described below.
The thermosetting resin contained in the thermosetting resin composition of the sealing material 40 includes, for example: epoxy resins, phenolic resins, cyanate resins, and the like are preferable from the viewpoints of mechanical strength, heat resistance, insulation, moldability, and the like.
The thermosetting resin composition may contain, in addition to the thermosetting resin, a phenolic resin curing agent, a curing agent such as an amine curing agent, a curing accelerator, an inorganic filler such as silica, and an additive such as an elastomer, as required.
The sealing material 40 may be solid or liquid at room temperature. The form of the sealing material 40 that is solid at room temperature is not particularly limited, and may be, for example, granular, sheet-like, or the like.
As a method of coating the semiconductor chip CP and the peripheral portion 30 thereof and the frame member 20 with the sealing material 40, any method may be appropriately selected from methods currently applied to semiconductor sealing processes, and for example, a roll lamination method, a vacuum lamination method, a spin coating method, a die coating method, a transfer molding method, a compression molding method, and the like may be applied.
In these methods, the sealing material 40 is heated at the time of coating to impart fluidity to the sealing material 40 in order to improve the filling property of the sealing material 40.
As shown in fig. 2 (D), after the coating step, the sealing material 40 is cured, and a cured sealing body 50 in which the semiconductor chip CP is sealed with the cured sealing material 41 is obtained.
As described above, the pressure-sensitive adhesive sheet 10 used in the present embodiment contains expandable particles that expand by heat, energy rays, or the like, and in step (4) described later, the adhesive force between the adhesive surface 12a and the cured sealing body 50 is reduced by expanding the expandable particles, so that the pressure-sensitive adhesive sheet 10 is peeled from the cured sealing body 50. Therefore, in the coating step and the curing step, it is preferable to coat and cure the sealing material 40 under a condition that the expandable particles do not expand.
For example, when the expandable particles contained in the pressure-sensitive adhesive sheet 10 are thermally expandable particles, the heating conditions (heating temperature and heating time) in the coating step and the curing step are preferably heating conditions in which the rate of increase in the thickness of the pressure-sensitive adhesive sheet 10 due to expansion of the thermally expandable particles is 10% or less, more preferably heating conditions in which the rate of increase is 5% or less, and even more preferably heating conditions in which the rate of increase is 0% (i.e., heating conditions in which the thermally expandable particles do not expand). The rate of increase in the thickness of the pressure-sensitive adhesive sheet 10 can be calculated based on the following formula by measuring the thickness of the pressure-sensitive adhesive sheet 10 before and after heating under a predetermined condition using a constant pressure gauge (product name "PG-02") in accordance with JIS K6783, Z1702, and Z1709, for example.
The thickness increase rate (%) = (thickness after heating-thickness before heating) ×100/thickness before heating, however, when the sealing material 40 is heated in the coating step, the sealing material 40 may be directly cured by the heating. That is, in this case, the coating step and the curing step may be performed simultaneously.
In the present embodiment, the case where the thermosetting resin composition is used as the sealing material 40 and the thermally expandable particles are used as the expandable particles has been described, but for example, the case where the sealing material 40 is an energy ray curable resin composition and the expandable particles are thermally expandable particles may be employed, and the case where the sealing material 40 is an energy ray curable resin composition and the expandable particles are energy ray expandable particles may be employed, and in these cases, it is preferable that the thickness increase rate of the adhesive sheet 10 in the coating step and the curing step satisfies the above range.
The specific example of the temperature at which the thermosetting resin composition is heated in the coating step varies depending on the type of the sealing material 40 to be used, the type of the expandable particles, and the like, and is, for example, 30 to 180 ℃, preferably 50 to 170 ℃, and more preferably 70 to 150 ℃. The heating time is, for example, 5 seconds to 60 minutes, preferably 10 seconds to 45 minutes, and more preferably 15 seconds to 30 minutes.
When the thermosetting resin composition is pressure-bonded in the coating step, the pressure of the pressure-bonding is, for example, 0.1 to 2.0MPa, preferably 0.2 to 1.8MPa, and more preferably 0.3 to 1.6MPa.
In the case of pressure-bonding the thermosetting resin composition while reducing the pressure in the coating step, the pressure is, for example, 0.1 to 5.0MPa, preferably 0.5 to 4.0MPa.
In the above curing step, the specific example of the temperature at which the sealing material 40 is cured varies depending on the type of the sealing material 40 used, the type of the expandable particles, and the like, and is, for example, 80 to 240 ℃, preferably 90 to 200 ℃, and more preferably 100 to 170 ℃. The heating time is, for example, 10 to 180 minutes, preferably 20 to 150 minutes, and more preferably 30 to 120 minutes.
In the present embodiment, the coating step and the curing step are preferably performed using a sheet-shaped sealing material (hereinafter, also referred to as a "sheet-shaped sealing material").
In the method using the sheet-like sealing material, the semiconductor chip CP and its peripheral portion 30 and the frame member 20 are covered with the sealing material 40 by placing the sheet-like sealing material so as to cover the semiconductor chip CP and its peripheral portion 30 and the frame member 20. At this time, heating and pressure bonding are preferably performed by vacuum lamination or the like while appropriately reducing pressure so that the portion where the sealing material 40 is not filled is not generated in the gap between the semiconductor chip CP and the frame member 20. The preferred modes of the conditions of pressure reduction, heating and pressure bonding are as described above. Then, the laminated sealing material 40 is heated to be cured. The preferred manner of curing temperature is as described above.
The sheet-like sealing material may be a laminate sheet supported by a resin sheet such as polyethylene terephthalate. In this case, the resin sheet may be peeled from the sealing material after the laminate sheet is placed so as to cover the semiconductor chip CP and the peripheral portion 30 thereof and the frame member 20 with the sheet-like sealing material.
In the case of using a sheet-like sealing material, the 1 st heating and pressing step may be performed after the sheet-like sealing material is laminated and before the step of thermally curing the sheet-like sealing material. In the 1 st heating and pressing step, the semiconductor chip CP and the adhesive sheet 10 covered with the sealing material 40 are sandwiched between plate-like members from both sides, and pressed under predetermined conditions of temperature, time and pressure. By performing the 1 st heating and pressing step, the sealing material 40 is easily filled into the space between the semiconductor chip CP and the frame member 20. Further, by performing the 1 st heating and pressing step, the irregularities of the sealing material layer formed of the sealing material 40 may be flattened. As the plate-like member, for example, a metal plate such as stainless steel can be used.
By the step (3), the cured sealing body 50 in which the plurality of semiconductor chips CP are embedded in the cured sealing material 41 can be obtained.
In the steps (4) and (5) described later, a step of forming a rewiring layer on the exposed surface after the pressure-sensitive adhesive sheet 10 is peeled off from the cured sealing body 50 is performed. In order to improve the operability of the cured sealing body 50 in these steps, a reinforcing member may be attached to the exposed surface (i.e., the surface opposite to the expandable base material) of the cured sealing body 50 as needed. The reinforcing member is not particularly limited, and is preferably a reinforcing plate having excellent heat resistance such as glass epoxy resin, for example, and is preferably adhered to the entire exposed surface of the cured sealing body 50. The reinforcing member may be attached by an adhesive layer, for example. The reinforcing member is removable after achieving the purpose thereof, and therefore, the adhesive layer is preferably fixed and peeled as needed.
The adhesion of the reinforcing member can be performed, for example, by a 2 nd heating and pressing step in which a thermosetting adhesive layer and a reinforcing plate are laminated in this order on the exposed surface of the cured sealing body 50, and then the reinforcing plate and the reinforcing plate are sandwiched between the reinforcing plate side and the adhesive sheet side, respectively, as needed, and the reinforcing member is pressed under predetermined conditions of temperature, time and pressure. In the 2 nd heat press step, a metal plate such as stainless steel can be used as the plate-like member.
(Process (4))
Fig. 2 (E) is a cross-sectional view illustrating the step (4), in which the expandable particles are expanded and the adhesive sheet 10 is peeled from the cured sealing body 50.
Specifically, by expanding the expandable particles by heat, energy rays, or the like according to the type thereof, irregularities are formed on the adhesive surface 12a of the adhesive layer 12, and thereby the adhesive force between the adhesive surface 12a and the cured sealing body 50 is reduced, and the adhesive sheet 10 is peeled off.
Step 4 is preferably performed in a state where the surface 11a of the substrate 11 opposite to the pressure-sensitive adhesive layer 12 is fixed by a fixing jig or the like. By fixing the surface 11a, the formation of irregularities on the surface 11a side can be suppressed when the expandable particles are expanded, whereby irregularities can be efficiently formed on the adhesive surface 12a side of the adhesive layer 12, and further excellent peelability can be obtained.
As shown in fig. 2 (E), in the present embodiment, the surface 11a of the adhesive sheet 10 is fixed using a suction table 90 having a plurality of suction holes 91 as the fixing jig. The suction table 90 has a pressure reducing device such as a vacuum pump, and sucks the object from the plurality of suction holes 91 by the pressure reducing device, thereby fixing the object to the suction surface.
The method for suppressing the occurrence of irregularities on the surface 11a side of the substrate 11 is not limited to the above-described method, and any method that can physically suppress the occurrence of irregularities on the surface 11a side of the substrate 11 may be used. As an example thereof, a method of adhering a hard support to the surface 11a by an arbitrary adhesive layer, a double-sided adhesive sheet, or the like is given.
The material of the hard support may be appropriately determined in consideration of mechanical strength, heat resistance, and the like, and examples thereof include: metal materials such as SUS; nonmetallic inorganic materials such as glass and silicon wafers; resin materials such as polyimide and polyamideimide; glass epoxy resin and the like. The thickness of the hard support may be appropriately determined in consideration of mechanical strength, handleability, and the like, and is, for example, 100 μm to 50mm.
The pressure-sensitive adhesive layer (hereinafter, also referred to as "the 2 nd pressure-sensitive adhesive layer") used for adhering the hard support is not particularly limited, and may be formed using a pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer 12. The 2 nd adhesive layer may be provided on the surface 11a side of the base material 11 in advance. In this case, the adhesive surface of the 2 nd adhesive layer may further have a release material. That is, the pressure-sensitive adhesive sheet 10 may have a structure of the pressure-sensitive adhesive layer 12/the base material 11/the 2 nd pressure-sensitive adhesive layer, or may have a structure of the release material/the pressure-sensitive adhesive layer 12/the base material 11/the 2 nd pressure-sensitive adhesive layer/the release material.
The method for expanding the expandable particles may be appropriately selected according to the type of expandable particles.
When the expandable particles are thermally expandable particles, the temperature may be heated to a temperature equal to or higher than the expansion initiation temperature (t). Here, the "temperature equal to or higher than the expansion start temperature (t)" is preferably equal to or higher than the expansion start temperature (t) +10deg.C "and equal to or lower than the expansion start temperature (t) +60deg.C", and more preferably equal to or higher than the expansion start temperature (t) +15deg.C "and equal to or lower than the expansion start temperature (t) +40deg.C". Specifically, the thermally expandable particles may be expanded by heating to a temperature in the range of 120 to 250 ℃, for example, depending on the type of the thermally expandable particles.
After the expandable particles are expanded, the adhesive sheet 10 is peeled from the cured sealing body 50. Since the adhesive sheet 10 of the present embodiment has excellent peelability, peeling can be performed with an external force smaller than that of the conventional temporary fixing sheet. The method of peeling is not particularly limited, and for example, peeling can be performed using a tape remover.
The production method of the present embodiment may include the following steps, as needed, before or after the release of the pressure-sensitive adhesive sheet 10 from the cured sealing body 50 in step (4): the surface of the cured sealing body 50 opposite to the rewiring layer forming surface is ground to reduce the thickness of the cured sealing body 50.
(Process (5))
The manufacturing method of the present embodiment preferably includes a step (5), and in the step (5), a rewiring layer is formed on the cured sealing body 50 from which the double-sided adhesive sheet 10 is peeled off.
Fig. 3 (a) is a cross-sectional view of the cured sealing body 50 after the release of the adhesive sheet 10.
In this step, a rewiring connected to the circuits W2 of the exposed plurality of semiconductor chips CP is formed on the circuit surface W1 and on the surface 50a of the cured sealing body 50 other than the region corresponding to the semiconductor chip CP.
Fig. 3 (B) is a cross-sectional view illustrating a step of forming the 1 st insulating layer 61 on the circuit surface W1 of the semiconductor chip CP and the surface 50a of the cured sealing member 50.
The 1 st insulating layer 61 containing an insulating resin is formed on the circuit surface W1 and the surface 50a to expose the circuit W2 of the semiconductor chip CP or the internal terminal electrode W3 of the circuit W2. The insulating resin may be: polyimide resin, polybenzoAzole resins, silicone resins, and the like. The material of the internal terminal electrode W3 is not limited as long as it is a conductive material, and examples thereof include: metals such as gold, silver, copper, and aluminum, and alloys containing these metals.
Fig. 3 (C) is a cross-sectional view illustrating a step of forming a rewiring 70 electrically connected to the semiconductor chip CP sealed in the cured sealing body 50.
In this embodiment mode, the re-wiring 70 is formed after the 1 st insulating layer 61 is formed. The material of the rewiring 70 is not limited as long as it is a conductive material, and examples thereof include: metals such as gold, silver, copper, and aluminum, and alloys containing these metals. The rewiring 70 may be formed by a known method such as a metal surface etching method or a semi-additive method.
Fig. 4 (a) is a cross-sectional view illustrating a step of forming the 2 nd insulating layer 62 covering the rewiring 70.
The rewiring 70 has an external electrode pad 70A for an external terminal electrode. An opening or the like is provided in the 2 nd insulating layer 62 to expose the external electrode pad 70A for the external terminal electrode. In the present embodiment, the external electrode pad 70A is exposed to the inside and outside of the region (region corresponding to the circuit surface W1) of the semiconductor chip CP of the cured sealing body 50 (region corresponding to the surface 50A on the cured sealing body 50). The rewiring 70 is formed on the surface 50A of the cured sealing body 50 so that the external electrode pads 70A are arranged in an array. In the present embodiment, the external electrode pad 70A is exposed to the outside of the region of the semiconductor chip CP of the cured sealing body 50, so that FOWLP or FOPLP can be obtained.
(connection step with external terminal electrode)
Fig. 4 (B) is a cross-sectional view illustrating a process of connecting the external terminal electrode 80 to the external electrode pad 70A.
The external terminal electrode 80 such as a solder ball is placed on the external electrode pad 70A exposed from the 2 nd insulating layer 62, and the external terminal electrode 80 and the external electrode pad 70A are electrically connected by soldering or the like. The material of the solder ball is not particularly limited, and examples thereof include lead-containing solder, lead-free solder, and the like.
(cutting step)
Fig. 4 (C) is a cross-sectional view illustrating a process of singulating the cured sealing body 50 connected to the external terminal electrode 80.
In this step, the cured sealing body 50 is singulated by the semiconductor chip CP unit. The method for singulating the cured sealing body 50 is not particularly limited, and may be performed by a cutting device such as a microtome (dicing saw).
By singulating the cured encapsulant 50, the semiconductor device 100 of the semiconductor chip CP unit can be manufactured. As described above, the semiconductor device 100 in which the external terminal electrode 80 is connected to the external electrode pad 70A outside the region fanned out to the semiconductor chip CP can be manufactured as FOWLP, FOPLP, or the like.
(mounting step)
In the present embodiment, the method preferably further includes a step of mounting the singulated semiconductor device 100 on a printed wiring board or the like.
Examples
The present invention is specifically described by the following examples, but the present invention is not limited to the following examples. The physical properties in the following production examples and examples were measured by the following methods.
Weight average molecular weight (Mw) >
The measurement was performed using a gel permeation chromatography apparatus (product name "HLC-8020" manufactured by Tosoh Co., ltd.) under the following conditions, and the measurement value converted into standard polystyrene was used.
(measurement conditions)
Chromatographic column: the columns were connected in this order by "TSK guard column HXL-L", "TSK gel G2500HXL", "TSK gel G2000HXL", "TSK gel G1000HXL" (manufactured by Tosoh Co., ltd.)
Column temperature: 40 DEG C
Elution solvent: tetrahydrofuran (THF)
Flow rate: 1.0 mL/min
< measurement of thickness of layers >
The measurement was performed using a constant pressure thickness gauge (model: PG-02J, according to JIS K6783, Z1702, Z1709) manufactured by Teclock Co.
< average particle diameter of thermally-expansive particles (D 50 ) 90% particle diameter (D) 90 )＞
The particle distribution of the thermally expandable particles before expansion at 23℃was measured using a laser diffraction type particle size distribution measuring apparatus (for example, manufactured by Malvern corporation under the product name "Mastersizer 3000").
Then, particle diameters corresponding to a cumulative volume frequency of 50% and 90% calculated from the particle diameter smaller in the particle distribution were taken as "average particle diameter of the thermally expandable particles (D 50 ) 90% of the particle diameter (D 90 )”。
< storage modulus E' >, of an expandable substrate
When the object to be measured is a non-adhesive expandable substrate, the expandable substrate is sized to be 5mm in the longitudinal direction and 30mm in the transverse direction and 200 μm in the thickness, and the substrate from which the release material was removed is used as a test sample.
The storage modulus E' of the test sample at a given temperature was measured using a dynamic viscoelasticity measuring apparatus (manufactured by TA Instruments Co., ltd., product name "DMAQ 800") under the conditions of a test start temperature of 0 ℃, a test end temperature of 300 ℃, a heating rate of 3 ℃ per minute, a vibration frequency of 1Hz, and an amplitude of 20. Mu.m.
< shear modulus G 'of adhesive layer, storage modulus E' of Expandable adhesive layer >
When the object to be measured is an expandable pressure-sensitive adhesive layer and pressure-sensitive adhesive layer having tackiness, the expandable pressure-sensitive adhesive layer and pressure-sensitive adhesive layer were made to have a diameter of 8mm×a thickness of 3mm, and the pressure-sensitive adhesive layer from which the release material was removed was used as a test sample.
The shear modulus G' of the test sample at a given temperature was measured by a torsional shear method using a viscoelasticity measuring apparatus (manufactured by Anton Paar Co., ltd., apparatus name "MCR 300") under the conditions of a test start temperature of 0 ℃, a test end temperature of 300 ℃, a temperature rising rate of 3 ℃/min and a vibration frequency of 1 Hz.
Then, based on the measured value of the shear modulus G ', the value of the storage modulus E ' is calculated according to the approximate expression "E ' =3g″.
< probe tack value >
The expandable base material or the expandable adhesive layer as the measurement object was cut into squares having a side length of 10mm, and then left to stand in an atmosphere of 50% RH (relative humidity) at 23℃for 24 hours, after which the light release film was removed, the resultant was used as a test sample.
The test sample was subjected to removal of the light release film, and the probe adhesion value of the exposed surface of the test sample was measured in accordance with JIS Z0237:1991 using an adhesion tester (product name "NTS-4800", manufactured by Japanese Seisakusho Kogyo Co., ltd.) at 23℃under 50% RH (relative humidity).
Specifically, the contact load was 0.98N/cm in 1 second 2 After a stainless steel probe having a diameter of 5mm was brought into contact with the surface of the test sample, the measurement was performedThe force required to move the probe away from the surface of the test sample at a speed of 10 mm/sec was measured. The measured value was then used as the probe tack value for the test sample.
The following details of the adhesive resin, additives, thermally expandable particles, and release material used in the production examples are as follows.
< adhesive resin >)
Acrylic copolymer (i): a solution comprising a weight average molecular weight (Mw) 60 ten thousand of an acrylic copolymer having a structural unit derived from a raw material monomer consisting of 2-ethylhexyl acrylate (2 EHA)/2-hydroxyethyl acrylate (HEA) =80.0/20.0 (mass ratio). Dilution solvent: ethyl acetate, solid content concentration: 40 mass%.
Acrylic copolymer (ii): a solution comprising a weight average molecular weight (Mw) 60 ten thousand of an acrylic copolymer having structural units derived from a raw material monomer consisting of n-Butyl Acrylate (BA)/Methyl Methacrylate (MMA)/2-hydroxyethyl acrylate (HEA)/acrylic acid=86.0/8.0/5.0/1.0 (mass ratio). Dilution solvent: ethyl acetate, solid content concentration: 40 mass%.
< additive >)
Isocyanate crosslinker (i): product name "Coronate L", manufactured by eastern co., ltd., solid content concentration: 75 mass%.
Photopolymerization initiator (i): BASF corporation, under the product name "Irgacure 184", 1-hydroxycyclohexyl phenyl ketone.
< thermally-expansive particles >)
Thermally expandable particles (i): manufactured by Kureha corporation, product name "S2640", expansion initiation temperature (t) =208 ℃, average particle diameter (D 50 ) =24 μm,90% particle size (D 90 )＝49μm。
< Release Material >)
Heavy release film: a release agent layer made of an organosilicon release agent was provided on one side of a polyethylene terephthalate (PET) film, and the thickness was as follows: 38 μm.
Light release film: the product name "SP-PET381031" manufactured by lindaceae is a film in which a release agent layer made of an organosilicon release agent is provided on one surface of a PET film, and the thickness is as follows: 38 μm.
Production example 1 (formation of adhesive layer (X))
5.0 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i) was blended with 100 parts by mass of the solid content of the acrylic copolymer (i) as an adhesive resin, diluted with toluene, and stirred uniformly to prepare a composition (x-1) having a solid content concentration (active ingredient concentration) of 25% by mass.
Then, the prepared composition (X-1) was applied onto the surface of the release agent layer of the heavy release film to form a coating film, and the coating film was dried at 100℃for 60 seconds to form an adhesive layer (X) having a thickness of 10. Mu.m.
The shear modulus G' (23) of the adhesive layer (X) at 23℃was 2.5X10 5 Pa。
Production example 2 (formation of an Expandable substrate (Y-1))
(1) Preparation of composition (y-1)
The terminal isocyanate urethane prepolymer obtained by reacting an ester diol with isophorone diisocyanate (IPDI) was reacted with 2-hydroxyethyl acrylate to obtain a 2-functional urethane acrylate oligomer having a weight average molecular weight (Mw) of 5000.
Then, 40 mass% (solid content ratio) of isobornyl acrylate (IBXA) and 20 mass% (solid content ratio) of phenyl hydroxypropyl acrylate (HPPA) as energy ray-polymerizable monomers were blended with 40 mass% (solid content ratio) of the above-synthesized urethane acrylate oligomer, and 2.0 mass parts (solid content ratio) of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF corporation under the product name "Irgacure 184") as a photopolymerization initiator and 0.2 mass parts (solid content ratio) of phthalocyanine pigment as an additive were further blended with 100 mass parts of the total amount of the urethane acrylate oligomer and the energy ray-polymerizable monomers, to prepare an energy ray-curable composition.
Then, the heat-expandable particles (i) were blended with the energy ray-curable composition to prepare a solvent-free composition (y-1) containing no solvent.
The content of the thermally expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the composition (y-1).
(2) Formation of an expandable substrate (Y-1)
The prepared composition (y-1) was coated on the surface of the release agent layer of the light release film to form a coating film.
Then, the irradiation was performed with an ultraviolet irradiation apparatus (product name "ECS-401GX" manufactured by Eye Graphics Co., ltd.) and a high-pressure mercury lamp (product name "H04-L41" manufactured by Eye Graphics Co., ltd.) at an illuminance of 160mW/cm 2 Light quantity 500mJ/cm 2 The film was cured by irradiation with ultraviolet rays under the conditions of (a) to form an expandable substrate (Y-1) having a thickness of 50. Mu.m. The illuminance and the light amount at the time of ultraviolet irradiation were measured using an illuminance/light meter (manufactured by EIT corporation under the product name "UV Power Puck II").
Production example 3 (formation of an Expandable substrate (Y-2))
(1) Synthesis of urethane prepolymers
In a reaction vessel under a nitrogen atmosphere, isophorone diisocyanate was blended with 100 parts by mass (solid component ratio) of a carbonate-type diol having a weight average molecular weight (Mw) of 1,000 so that the equivalent ratio of the hydroxyl group of the carbonate-type diol to the isocyanate group of isophorone diisocyanate (IPDI) was 1/1, 160 parts by mass of toluene was further added, and the mixture was reacted at 80℃for 6 hours or more while stirring under a nitrogen atmosphere until the isocyanate group concentration reached the theoretical amount.
Then, a solution obtained by diluting 1.44 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA) in 30 parts by mass of toluene was added, and the mixture was further reacted at 80 ℃ for 6 hours or more until the isocyanate groups at both ends disappeared, whereby a urethane prepolymer having a weight average molecular weight (Mw) of 2.9 ten thousand was obtained.
(2) Synthesis of acrylic urethane resin
100 parts by mass (solid content ratio) of the urethane prepolymer obtained in the above (1), 117 parts by mass (solid content ratio) of Methyl Methacrylate (MMA), 5.1 parts by mass (solid content ratio) of 2-hydroxyethyl methacrylate (2-HEMA), 1.1 parts by mass (solid content ratio) of 1-thioglycerol, and 50 parts by mass of toluene were charged into a reaction vessel under a nitrogen atmosphere, and the mixture was stirred and heated to 105 ℃.
Then, a solution of 2.2 parts by mass (solid content ratio) of a radical initiator (product name "ABN-E" manufactured by Japan Finechem corporation) diluted with 210 parts by mass of toluene was further added dropwise to the reaction vessel while maintaining the temperature at 105 ℃ for 4 hours.
After completion of the dropwise addition, the reaction was carried out at 105℃for 6 hours to obtain a solution of an acrylic urethane resin having a weight average molecular weight (Mw) of 10.5 ten thousand.
(3) Formation of an expandable substrate (Y-2)
6.3 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i), 1.4 parts by mass (solid content ratio) of dioctyltin bis (2-ethylhexanoate) as a catalyst, and the thermally expandable particles (i) were mixed with 100 parts by mass of the solid content of the solution of the acrylic urethane resin obtained in the above (2), diluted with toluene, and stirred uniformly to prepare a composition (y-2) having a solid content (active ingredient concentration) of 30% by mass.
The content of the thermally expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the active ingredient in the obtained composition (y-2).
Then, the prepared composition (Y-2) was applied onto the surface of the release agent layer of the light release film to form a coating film, and the coating film was dried at 100℃for 120 seconds to form an expandable substrate (Y-2) having a thickness of 50. Mu.m.
Production example 4 (formation of Expandable adhesive layer (Y-3))
6.3 parts by mass (solid content ratio) of the isocyanate-based crosslinking agent (i) and the thermally expandable particles (i) were mixed with 100 parts by mass of the solid content of the acrylic copolymer (ii) as the adhesive resin, and diluted with toluene and stirred uniformly to prepare a composition (y-3) having a solid content concentration (active ingredient concentration) of 30% by mass.
The content of the thermally expandable particles (i) was 20% by mass relative to the total amount (100% by mass) of the active ingredient in the obtained composition (y-3).
Then, the prepared composition (Y-3) was applied onto the surface of the release agent layer of the light release film to form a coating film, and the coating film was dried at 100℃for 120 seconds to form an expandable adhesive layer (Y-3) having a thickness of 50. Mu.m.
The storage modulus E' and the probe tack value at 23℃and 100℃and 208℃were measured for the expandable substrates (Y-1) to (Y-2) formed in production examples 2 to 3 and the expandable adhesive layer (Y-3) formed in production example 4, respectively, based on the above-mentioned methods, wherein 208℃is the expansion initiation temperature of the heat-expandable particles used. These results are shown in table 1.
TABLE 1
Example 1
The pressure-sensitive adhesive layer (X) formed in production example 1 and the surface of the expandable substrate (Y-1) formed in production example 2 were bonded to each other, and a pressure-sensitive adhesive sheet (1) in which a light release film/expandable substrate (Y-1)/pressure-sensitive adhesive layer (X)/heavy release film were laminated in this order was produced.
Example 2
An adhesive sheet (2) in which a light release film/an expandable substrate (Y-2)/an adhesive layer (X)/a heavy release film were laminated in this order was produced in the same manner as in example 1, except that the expandable substrate (Y-1) was replaced with the expandable substrate (Y-2) formed in production example 3.
Comparative example 1
An adhesive sheet (3) in which a light release film/an expandable adhesive layer (Y-3)/an adhesive layer (X)/a heavy release film were laminated in this order was produced in the same manner as in example 1, except that the expandable base material (Y-1) was replaced with the expandable adhesive layer (Y-3) formed in production example 4.
Comparative example 2
The light release film/expandable adhesive layer (Y-3) formed in production example 4 was used as the adhesive sheet (4) as it is.
The following measurements were performed on the produced pressure-sensitive adhesive sheets (1) to (4). These results are shown in table 2.
< evaluation of positional deviation of semiconductor chip in sealing Process >)
The heavy release film is peeled from the pressure-sensitive adhesive sheets (1) to (3) to expose the pressure-sensitive adhesive layer (X). Then, a copper frame member having a predetermined number of 10mm×10mm openings was adhered to the adhesive surface of the adhesive layer (X) of the adhesive sheets (1) to (3) and the expandable adhesive layer (Y-3) of the adhesive sheet (4).
Next, the light release film is removed from the adhesive sheets (1) to (4), and the exposed expandable base material or expandable adhesive layer is fixed to the suction surface of a suction stage having a plurality of suction holes as shown in fig. 2 (E).
Next, 9 semiconductor chips (chip size 6.4mm×6.4mm, chip thickness 200 μm (# 2000)) were placed on the adhesive surface exposed at the plurality of openings at a necessary interval from the frame member so that the adhesive surface was in contact with the circuit surface of the semiconductor chip.
Then, a sealing resin film (sealing material) was laminated on the adhesive surface, the frame member and the semiconductor chip, and the adhesive surface, the frame member and the semiconductor chip were covered with the sealing material using a vacuum-heated and pressurized laminator (7024 HP5 manufactured by ROHM and HAAS company), and the sealing material was cured, to prepare a cured sealing body. The sealing conditions are as follows.
Preheating temperature: the workbench and the membrane are all 100 DEG C
Vacuum suction: 60 seconds
Dynamic compaction mode: 30 seconds
Static press mode: for 10 seconds
Sealing temperature: 180 ℃ (a temperature lower than the expansion initiation temperature of the thermally expandable particles by 208 ℃)
Sealing time: 60 minutes
After sealing, the adhesive sheets (1) to (4) were heated at 240℃higher than the expansion initiation temperature (208 ℃) of the thermally expandable particles for 3 minutes, the cured sealing body was separated from the adhesive sheets (1) to (4), and the surface (re-wiring layer forming surface) of the separated cured sealing body was observed with naked eyes and a microscope to confirm the presence or absence of positional displacement of the semiconductor chip, and the evaluation was made according to the following criteria.
A: the semiconductor chip having a positional shift of 25 μm or more than before sealing was not confirmed.
F: the semiconductor chip was confirmed to have a positional shift of 25 μm or more than before sealing.
Evaluation of flatness of semiconductor chip-side surface after sealing Process
Using the adhesive sheets (1) to (4), a cured sealing body was produced in the same manner as the above-described "evaluation of positional deviation of semiconductor chips during the sealing step", and was separated from the adhesive sheet.
The surface (re-wiring layer formation surface) of each semiconductor chip side of the cured sealing body produced was measured using a contact surface roughness measuring instrument (SV 3000 manufactured by Mitutoyo corporation), and the level difference was evaluated according to the following criteria.
A: the region where the difference in height of 2 μm or more was generated was not confirmed.
F: it was confirmed that a difference in height of 2 μm or more was generated.
< measurement of adhesive force of adhesive sheet before and after heating >)
An adhesive sheet from which the re-release films of the adhesive sheets (1) to (3) were removed and an adhesive sheet (4) were prepared, and the adhesive layer (X) or the expandable adhesive layer (Y-3) was adhered to a stainless steel plate (SUS 304 360) as an adherend, and left to stand at 23℃under 50% RH (relative humidity) for 24 hours, respectively, to give test samples.
Then, using the above-mentioned test sample, the adhesive force at 23℃was measured by 180℃peeling at a stretching speed of 300 mm/min based on JIS Z0237:2000 under an atmosphere of 23℃and 50% RH (relative humidity).
The test sample was heated on a hot plate at 240℃which is higher than the expansion initiation temperature (208 ℃) of the thermally expandable particles for 3 minutes, allowed to stand in a standard atmosphere (23 ℃ C., 50% RH (relative humidity)) for 60 minutes, and then the adhesive force after heating at 300 mm/min at the expansion initiation temperature or higher was measured by a 180 DEG peeling method according to JIS Z0237:2000.
When the adhesion was difficult to measure by the degree to which the adhesive force could not be adhered to the adherend stainless steel sheet, the adhesive force was evaluated as "no measurement", and was set to 0 (N/25 mm).
As is clear from table 2, according to the manufacturing method of the adhesive sheets (1) and (2) using examples 1 and 2, the effect of suppressing the sinking of the semiconductor chip is good in the heating at the time of the sealing step, and therefore, the positional shift of the semiconductor chip is not observed, and the surface (the rewiring layer forming surface) on the semiconductor chip side after the sealing step is also flat.
In addition, the adhesive sheets (1) and (2) have good adhesive force before heating, but the adhesive force after heating at a temperature equal to or higher than the expansion initiation temperature is reduced to an undetectable level, and as a result, it was confirmed that peeling can be easily performed with a slight force at the time of peeling.
On the other hand, the adhesive sheets (3) and (4) of comparative example 1 and 2 do not have an expandable base material, but have an expandable adhesive layer, and therefore, sinking of the semiconductor chip occurs during heating in the sealing step, positional displacement of the semiconductor chip is observed, and a level difference is observed on the surface (re-wiring layer formation surface) of the semiconductor chip side after the sealing step. Therefore, it is considered that it is not suitable for use in, for example, a sealing process in the production of FOWLP and FOPLP.

Claims (11)

1. A method for manufacturing a semiconductor device using an adhesive sheet having an adhesive layer and a non-adhesive base material containing expandable particles,
the storage modulus E' (t) of the substrate at 23 ℃ is 1.0X10 6 Pa or more，
The method comprises the following steps (1) to (4),
step (1): a step of adhering the frame member having the opening formed thereon to the adhesive surface of the adhesive layer;
step (2): a step of placing a semiconductor chip on a part of an adhesive surface of the adhesive layer exposed at the opening of the frame member;
step (3): a step of covering a peripheral portion of the semiconductor chip, the frame member, and the adhesive surface of the adhesive layer with a sealing material, and curing the sealing material to obtain a cured sealing body in which the semiconductor chip is sealed with the cured sealing material;
Step (4): and a step of expanding the expandable particles and peeling the adhesive sheet from the cured sealing body.
2. The method for manufacturing a semiconductor device according to claim 1, further comprising the step (5),
step (5): and forming a rewiring layer on the cured sealing body after the adhesive sheet is peeled off.
3. The method for manufacturing a semiconductor device according to claim 1, wherein,
the expandable particles are thermally expandable particles,
the step (4) is a step of heating the adhesive sheet to expand the thermally expandable particles and peeling the adhesive sheet from the cured sealing body.
4. The method for manufacturing a semiconductor device according to claim 3, wherein the expansion initiation temperature (t) of the thermally expandable particles is 120 to 250 ℃.
5. The method for manufacturing a semiconductor device according to claim 4, wherein the substrate satisfies the following requirements (1) to (2),
element (1): energy storage of the substrate at 100 DEG CModulus E' (100) of 2.0X10 5 Pa or more;
element (2): the substrate has a storage modulus E' (t) of 1.0X10 at the expansion initiation temperature (t) of the thermally expandable particles 7 Pa or below.
6. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein an average particle diameter of the expandable particles before expansion at 23 ℃ is 3 to 100 μm.
7. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein a shear modulus G' (23) of the adhesive layer at 23 ℃ is 1.0 x 10 4 ～1.0×10 8 Pa。
8. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein a ratio of a thickness of the base material to a thickness of the adhesive layer (base material/adhesive layer) is 0.2 or more at 23 ℃.
9. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein the thickness of the base material is 10 to 1000 μm and the thickness of the adhesive layer is 1 to 60 μm at 23 ℃.
10. The method for manufacturing a semiconductor device according to any one of claims 1 to 5, wherein a probe viscosity value of the substrate surface is less than 50mN/5mm Φ.
11. An adhesive sheet used in the method for producing a semiconductor device according to any one of claims 1 to 10, the adhesive sheet comprising an adhesive layer and a non-adhesive base material containing expandable particles.
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