JP7185638B2 - Semiconductor device manufacturing method - Google Patents

Description

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

2. Description of the Related Art In recent years, electronic devices have become smaller, lighter, and more functional, and along with this, semiconductor devices mounted in electronic devices are also required to be smaller, thinner, and higher in density.
A semiconductor chip is sometimes mounted in a package close to its size. Such a package is sometimes called a CSP (Chip Scale Package). Examples of CSP include WLP (Wafer Level Package), which is completed by processing up to the final package process on a wafer size, and PLP (Panel Level Package), which is completed by processing up to the final package process on a panel size larger than the wafer size. .

WLP and PLP are classified into fan-in type and fan-out type. In fan-out type WLP (hereinafter also referred to as "FOWLP") and PLP (hereinafter also referred to as "FOPLP"), a semiconductor chip is covered with a sealing material so as to have a region larger than the chip size. A rewiring layer and external electrodes are formed not only on the circuit surface of the semiconductor chip but also on the surface region of the encapsulant.
For example, in Patent Document 1, a plurality of semiconductor chips separated from a semiconductor wafer are surrounded by a molding member to form an extended wafer, leaving the circuit formation surface thereof, and forming an extended wafer in a region outside the semiconductor chip. A method for manufacturing a semiconductor package in which a rewiring pattern is formed by extending is described. In the manufacturing method described in Patent Literature 1, a semiconductor wafer is subjected to a dicing process in which the wafer is attached to a wafer mount tape for dicing (hereinafter, also referred to as a "dicing tape") and separated into individual pieces. A plurality of semiconductor chips obtained in the dicing process are transferred to a wafer mount tape for expansion (hereinafter also referred to as "expanding tape"), and the expanding tape is spread to increase the distance between the plurality of semiconductor chips. An expanding process is applied.

A dicing tape is used in the manufacturing process of semiconductor devices to singulate workpieces such as semiconductor wafers. While adhesive strength is required, separability that allows easy separation of individualized chips after dicing is also required.
As a dicing tape with improved separability after dicing, Patent Document 2 has a base material and an adhesive layer, and as a material for the adhesive layer, dicing using a material that is cured by ultraviolet irradiation to reduce adhesive strength. A tape is disclosed.

WO2010/058646 JP 2016-167510 A

However, in the dicing tape described in Patent Document 2, the chip and the adhesive layer are adhered over the entire adhesive surface even after ultraviolet irradiation, so that some degree of adhesive strength remains. Therefore, when the chips obtained by dicing are subjected to the next process, the process may be complicated, such as picking up the chips one by one.

Further, in the manufacturing process of the fan-out type package, as in the manufacturing method described in Patent Document 1, the semiconductor chips obtained by dicing may be moved onto an expanding tape.
As for the transfer, a method of directly transferring the semiconductor chip from the dicing tape to the expanding tape, and a method of transferring the semiconductor chip from the dicing tape to another adhesive sheet and transferring from the other adhesive sheet to the expanding tape are assumed. In either case, from the viewpoint of productivity, it is desirable to collectively transfer a plurality of semiconductor chips.
However, as in the dicing tape described in Patent Document 2, if a certain amount of adhesive strength remains after ultraviolet irradiation, a certain external force is required to separate the dicing tape from the semiconductor chip. Complex equipment is required to effect the separation.
In addition, since a load is applied to the semiconductor chips during separation, there is a problem that the semiconductor chips are likely to be misaligned and chipped.

The present invention has been made in view of the above problems, and is capable of easily transferring a plurality of chips obtained by dicing a workpiece to another adhesive sheet, and performing the transfer. It is an object of the present invention to provide a method of manufacturing a semiconductor device that can effectively suppress the occurrence of chip chipping during manufacturing.

The present inventors have developed a method for manufacturing a semiconductor device using an expandable adhesive sheet having a base material and an adhesive layer and containing expandable particles in any of the layers, comprising specific steps (1) to We have found that the above problems can be solved by a manufacturing method having (3).
That is, the present invention relates to the following [1] to [11].
[1] A method for manufacturing a semiconductor device using an expandable adhesive sheet (A) having a substrate (Y1) and an adhesive layer (X1) and containing expandable particles in one of the layers,
A method for manufacturing a semiconductor device, comprising the following steps (1) to (3) in this order.
Step (1): After attaching a workpiece to the adhesive layer (X1) of the adhesive sheet (A), the workpiece is diced and a plurality of individualized chips are formed on the adhesive layer (X1). The process of obtaining
Step (2): Using an adhesive sheet (B) having a substrate (Y2) and an adhesive layer (X2), on the surface opposite to the surface in contact with the adhesive layer (X1) of the plurality of chips, A step of attaching the adhesive layer (X2) of the adhesive sheet (B).
Step (3): A step of expanding the expandable particles to separate the plurality of chips attached to the adhesive sheet (B) from the adhesive sheet (A).
[2] The method for manufacturing a semiconductor device according to [1] above, wherein the adhesive sheet (B) is an adhesive sheet for expansion, and further includes the following step (4A) after the step (3).
Step (4A): A step of stretching the adhesive sheet (B) to widen the gaps between the plurality of chips attached to the adhesive sheet (B).
[3] Using a pressure-sensitive adhesive sheet (C) for expansion having a substrate (Y3) and a pressure-sensitive adhesive layer (X3), the following steps (4B-1) to (4B-3) are further performed, above [1 ] The manufacturing method of the semiconductor device according to .
Step (4B-1): Attach the adhesive layer (X3) of the adhesive sheet (C) to the surface of the plurality of chips on the adhesive sheet (B) opposite to the surface in contact with the adhesive layer (X2). process.
Step (4B-2): A step of separating the adhesive sheet (B) from the plurality of chips attached to the adhesive sheet (C).
Step (4B-3): A step of stretching the adhesive sheet (C) to widen the gaps between the plurality of chips attached to the adhesive sheet (C).
[4] The method for manufacturing a semiconductor device according to [2] or [3] above, wherein the adhesive sheet for expansion has a breaking elongation of 100% or more measured in the MD direction and the CD direction at 23°C.
[5] The expandable particles are thermally expandable particles having an expansion start temperature (t) of 60 to 270° C., and the step (3) heats the adhesive sheet (A) to obtain the adhesive sheet ( The method for manufacturing a semiconductor device according to any one of [1] to [4] above, wherein the step of separating the plurality of chips attached to B) from the adhesive sheet (A).
[6] The method for manufacturing a semiconductor device according to any one of [1] to [5] above, wherein step (1) includes stretching the adhesive sheet (A) after dicing the workpiece.
[7] The above [1] to the above, wherein the adhesive layer (X1) of the adhesive sheet (A) has an adhesive strength of 0.1 to 10.0 N/25 mm at 23° C. before the expandable particles expand. A method for manufacturing a semiconductor device according to any one of [6].
[8] The method for manufacturing a semiconductor device according to any one of [1] to [7] above, wherein the surface of the substrate (Y1) of the adhesive sheet (A) has a probe tack value of less than 50 mN/5 mmφ.
[9] The semiconductor according to any one of [1] to [8] above, wherein the substrate (Y1) of the adhesive sheet (A) is an expandable substrate (Y1-1) containing the expandable particles. Method of manufacturing the device.
[10] The method of manufacturing a semiconductor device according to any one of [1] to [9] above, wherein the workpiece is a semiconductor wafer.
[11] The method for manufacturing a semiconductor device according to [10] above, which is a method for manufacturing a fan-out semiconductor device.

According to the present invention, a plurality of chips obtained by dicing a workpiece can be easily transferred to another adhesive sheet, and chip chipping during transfer can be effectively suppressed. It is possible to provide a method for manufacturing a semiconductor device that can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of (a) adhesive sheet a1, (b) adhesive sheet b1 which shows an example of a structure of the adhesive sheet (A) used with the manufacturing method which concerns on this embodiment. It is sectional drawing explaining an example of the manufacturing method which concerns on this embodiment. FIG. 3 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 2 ; FIG. 4 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 3 ; FIG. 5 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment following FIG. 4 ; FIG. 6 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 5 ; FIG. 7 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 6 ; FIG. 8 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment following FIG. 7 ; FIG. 9 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 8 ; FIG. 10 is a cross-sectional view illustrating an example of the manufacturing method according to the present embodiment subsequent to FIG. 9; It is a top view explaining the biaxial stretching expansion apparatus used in the Example.

As used herein, the term “active ingredient” refers to the components contained in the target composition, excluding the diluent solvent.
Further, the mass average molecular weight (Mw) is a value converted to standard polystyrene measured by gel permeation chromatography (GPC), specifically a value measured based on the method described in Examples.

In this specification, for example, "(meth)acrylic acid" indicates both "acrylic acid" and "methacrylic acid", and the same applies to other similar terms.
Moreover, the lower limit value and upper limit value described stepwise for preferable numerical ranges (for example, ranges of content etc.) can be independently combined. For example, from the statement "preferably 10 to 90, more preferably 30 to 60", combining "preferred lower limit (10)" and "more preferred upper limit (60)" to "10 to 60" can also

As used herein, the term “chip transfer” means that the exposed surface of a chip attached to one adhesive sheet is attached to the other adhesive sheet, and then the one adhesive sheet is separated from the chip. and move the chip from one adhesive sheet to the other.

The method for manufacturing a semiconductor device according to the present embodiment has a substrate (Y1) and an adhesive layer (X1), and a semiconductor using an expandable adhesive sheet (A) containing expandable particles in one of the layers A device manufacturing method comprising the following steps (1) to (3) in this order.
Step (1): After attaching a workpiece to the adhesive layer (X1) of the adhesive sheet (A), the workpiece is diced and a plurality of individualized chips are formed on the adhesive layer (X1). The process of obtaining
Step (2): Using an adhesive sheet (B) having a substrate (Y2) and an adhesive layer (X2), on the surface opposite to the surface in contact with the adhesive layer (X1) of the plurality of chips, A step of attaching the adhesive layer (X2) of the adhesive sheet (B).
Step (3): A step of expanding the expandable particles to separate the plurality of chips attached to the adhesive sheet (B) from the adhesive sheet (A).
Workpieces used in the present embodiment include, for example, semiconductor wafers, LEDs (Light Emitting Diodes), MEMS (Micro Electro Mechanical Systems), ceramic devices, semiconductor packages, semiconductor devices having multiple devices, etc. and those that are diced in.
Further, in the present specification, the term "chip" means a piece obtained by dividing the workpiece.
Hereinafter, the pressure-sensitive adhesive sheet (A) used in the manufacturing method of the present embodiment will be described first, and then each manufacturing process including steps (1) to (3) will be described.

[Adhesive sheet (A)]
The pressure-sensitive adhesive sheet (A) is an expandable pressure-sensitive adhesive sheet having a substrate (Y1) and pressure-sensitive adhesive layers (X1) and containing expandable particles in any of the layers.
Before the expandable particles are expanded, the adhesive sheet (A) can firmly fix the workpiece by the adhesive surface of the adhesive layer (X1). Dicing can be performed with good workability while suppressing positional displacement of the workpiece.
On the other hand, when separating the adhesive sheet (A) and the chips obtained by dicing the work piece, the expandable particles are expanded to form irregularities on the adhesive surface of the adhesive layer (X1). By reducing the contact area between the adhesive surface of the adhesive layer (X1) and the chip, the adhesive strength can be made smaller than that of a conventional ultraviolet-curing dicing tape. As a result, a plurality of chips obtained by dicing can be easily transferred collectively to another adhesive sheet without requiring a complicated manufacturing apparatus, and at that time, positional displacement and chipping of chips can be prevented. It is also possible to suppress the occurrence of
Further, when separating the adhesive sheet (A) and the chips, by partially heating the adhesive sheet (A), not all the chips obtained by dicing but some of the obtained chips can be used. It is also possible to selectively separate some chips. Specifically, a plurality of chips obtained by dicing are divided into a plurality of units, and each unit is transferred to another adhesive sheet.

FIGS. 1(a) and 1(b) are cross-sectional schematic diagrams of adhesive sheets 1a and 1b, which are one mode of the adhesive sheet (A).
In one aspect of the present invention, like the adhesive sheets 1a and 1b, the base material (Y1) is preferably an expandable base material (Y1-1) containing expandable particles.

The pressure-sensitive adhesive sheet 1a shown in FIG. 1(a) has a pressure-sensitive adhesive layer (X1) on one side of a substrate (Y1-1). The adhesive sheet 1a is obtained by attaching a work piece onto the adhesive layer (X1), dicing the work piece to obtain a plurality of chips, and then separating the chips. When separating the adhesive sheet 1a and the chip, the expandable particles in the substrate (Y1-1) are expanded to generate irregularities on the surface of the adhesive layer (X1) in contact with the chip, and the adhesive Separation at the interface between layer (X1) and the chip can be facilitated.

The adhesive sheet 1b shown in FIG. 1(b) has an adhesive layer (X1) on one side of a substrate (Y1-1) and a non-expanding substrate (Y1') on the other side. The adhesive sheet 1b is used in the same manner as the adhesive sheet 1a, but when the expandable particles in the base material (Y1-1) are expanded, the non-expandable base material (Y1') is present. By doing so, it is possible to suppress the occurrence of unevenness on the surface of the non-expanding substrate (Y1′) side of the substrate (Y1-1), and thereby the unevenness on the surface of the pressure-sensitive adhesive layer (X1) side can be reduced more efficiently. can be formed

The structure of the pressure-sensitive adhesive sheet (A) is not limited to the structures shown in FIGS. 1(a) and (b). A configuration having another layer between the layer (X1) may be employed. However, from the viewpoint of obtaining a pressure-sensitive adhesive sheet that can be separated with a slight force, it is preferable to have a structure in which the substrate (Y1) and the pressure-sensitive adhesive layer (X1) are directly laminated. Moreover, the structure which has another adhesive layer on the surface on the opposite side to the adhesive layer (X1) of a base material (Y1) may be sufficient.
The adhesive sheet (A) may have a release material on the adhesive layer (X1). The release material is appropriately peeled off and removed when the pressure-sensitive adhesive sheet (A) is used in the manufacturing method according to the present embodiment.
The pressure-sensitive adhesive sheet (A) may have any shape such as sheet, tape, label, and the like.

(expansive particles)
The pressure-sensitive adhesive sheet (A) contains expandable particles in either the substrate (Y1) or the pressure-sensitive adhesive layer (X1).
The expandable particles are particularly limited as long as they expand themselves by an external stimulus to form unevenness on the adhesive surface of the adhesive layer (X1) and reduce the adhesive force to the adherend. not.
The expandable particles include, for example, thermally expandable particles that expand when heated, and energy linearly expandable particles that expand when irradiated with energy rays. is preferred.

The thermally expandable particles have an expansion initiation temperature (t) of preferably 60 to 270°C, more preferably 70 to 260°C, still more preferably 80 to 250°C.
In this specification, the expansion start temperature (t) of thermally expandable particles means a value measured based on the following method.
[Method for measuring expansion start temperature (t) of thermally expandable particles]
An aluminum cup with a diameter of 6.0 mm (inner diameter of 5.65 mm) and a depth of 4.8 mm was filled with 0.5 mg of thermally expandable particles to be measured, and an aluminum lid (5.6 mm in diameter and 0.6 mm in thickness) was placed thereon. 1 mm) is placed on the sample.
Using a dynamic viscoelasticity measuring device, the height of the sample is measured while a force of 0.01 N is applied to the sample from the top of the aluminum lid with a pressurizer. and. Heat from 20°C to 300°C at a heating rate of 10°C/min while applying a force of 0.01 N from the pressurizer, measure the amount of displacement in the vertical direction of the pressurizer, and start displacement in the positive direction. Let the temperature be the expansion start temperature (t).

The thermally expandable particles are microencapsulated foaming agents composed of an outer shell made of a thermoplastic resin and an encapsulated component that is encapsulated in the outer shell and vaporizes when heated to a predetermined temperature. Preferably.
Examples of thermoplastic resins constituting the outer shell of the microencapsulated foaming agent include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone.

Examples of encapsulated components encapsulated in the outer shell include propane, butane, pentane, hexane, heptane, octane, nonane, decane, isobutane, isopentane, isohexane, isoheptane, isooctane, isononane, isodecane, cyclopropane, cyclobutane, and cyclopentane. , cyclohexane, cycloheptane, cyclooctane, neopentane, dodecane, isododecane, cyclotridecane, hexylcyclohexane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nanodecane, isotridecane, 4-methyldodecane, isotetradecane, isopentadecane, iso Hexadecane, 2,2,4,4,6,8,8-heptamethylnonane, isoheptadecane, isooctadecane, isonanodecane, 2,6,10,14-tetramethylpentadecane, cyclotridecane, heptylcyclohexane, n-octylcyclohexane , cyclopentadecane, nonylcyclohexane, decylcyclohexane, pentadecylcyclohexane, hexadecylcyclohexane, heptadecylcyclohexane, octadecylcyclohexane and the like. These inclusion components may be used alone or in combination of two or more.
The expansion start temperature (t) of the thermally expandable particles can be adjusted by appropriately selecting the type of inclusion component.

The maximum volume expansion coefficient when heated to a temperature equal to or higher than the thermal expansion starting temperature (t) of the thermally expandable particles is preferably 1.5 to 100 times, more preferably 2 to 80 times, and still more preferably 2.5 to 60 times, more preferably 3 to 40 times.

The average particle size of the expandable particles at 23° C. before expansion is preferably 3-100 μm, more preferably 4-70 μm, even more preferably 6-60 μm, and even more preferably 10-50 μm.
The average particle size of the expandable particles before expansion is the volume-median particle size (D ₅₀ ), and is measured by a laser diffraction particle size distribution analyzer (for example, manufactured by Malvern, product name "Mastersizer 3000"). In the particle distribution of the expansive particles before expansion measured using the above method, the particle size corresponds to a cumulative volume frequency of 50% calculated from the smallest particle size of the expansive particles before expansion.

The 90% particle diameter (D ₉₀ ) of the expandable particles at 23° C. before expansion is preferably 10 to 150 μm, more preferably 20 to 100 μm, still more preferably 25 to 90 μm, still more preferably 30 to 80 μm. .
The 90% particle diameter (D ₉₀ ) of the expandable particles before expansion is measured using a laser diffraction particle size distribution analyzer (for example, manufactured by Malvern, product name “Mastersizer 3000”). In the particle distribution of the expandable particles in (1), the particle size corresponds to a cumulative volume frequency of 90% calculated from the smaller particle size of the expandable particles before expansion.

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

(Base material (Y1))
The base material (Y1) of the adhesive sheet (A) is a non-adhesive base material.
In the present invention, whether or not the substrate is non-adhesive is determined if the probe tack value measured in accordance with JIS Z0237:1991 is less than 50 mN/5 mmφ against the surface of the target substrate. The substrate is judged as a "non-adhesive substrate".
Here, the probe tack value on the surface of the substrate (Y1) used in the present embodiment is usually less than 50 mN/5 mmφ, preferably less than 30 mN/5 mmφ, more preferably less than 10 mN/5 mmφ, still more preferably 5 mN. /5 mmφ.
In this specification, a specific method for measuring the probe tack value on the surface of the substrate (Y1) is according to the method described in Examples.

The thickness of the substrate (Y1) is preferably 10-1000 μm, more preferably 20-500 μm, still more preferably 25-400 μm, still more preferably 30-300 μm.
In addition, in this specification, the thickness of a base material means the value measured by the method as described in an Example.

The substrate (Y1) can be formed from the resin composition (y1). Each component contained in the resin composition (y1), which is the material for forming the substrate (Y1), will be described below.

〔resin〕
The resin contained in the resin composition (y1) is not particularly limited as long as it is a resin that makes the substrate (Y1) non-adhesive, and may be a non-adhesive resin or an adhesive resin. good. That is, even if the resin contained in the resin composition (y1) is an adhesive resin, in the process of forming the base material (Y1) from the resin composition (y1), the adhesive resin undergoes a polymerization reaction with the polymerizable compound. Then, the obtained resin is a non-adhesive resin, and the substrate (Y1) containing the resin is non-adhesive.

The mass average molecular weight (Mw) of the resin contained in the resin composition (y1) is preferably 1,000 to 1,000,000, more preferably 1,000 to 700,000, and still more preferably 1,000 to 500,000. .
When the resin is a copolymer having two or more structural units, the form of the copolymer is not particularly limited, and may be a block copolymer, a random copolymer, or a graft copolymer. good too.

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, relative to the total amount (100% by mass) of the active ingredients in the resin composition (y1). % by mass, more preferably 70 to 85% by mass.

The resin contained in the resin composition (y1) preferably contains one or more selected from acrylic urethane resins and olefin resins. As the acrylic urethane resin, an acrylic urethane resin (U1) obtained by polymerizing a urethane prepolymer (UP) and a vinyl compound containing a (meth)acrylic acid ester is preferable. These resins are suitable from the viewpoint of expandability, particularly when the resin composition (y1) contains expandable particles.

[Acrylic urethane resin (U1)]
Examples of the urethane prepolymer (UP) that forms the main chain of the acrylic urethane resin (U1) include reaction products of polyols and polyvalent isocyanates.
In addition, it is preferable that the urethane prepolymer (UP) is obtained by subjecting the urethane prepolymer (UP) to a chain extension reaction using a chain extension agent.

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

Examples of ester diols include alkanediols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol and 1,6-hexanediol; ethylene glycol, propylene glycol, Diethylene glycol, alkylene glycol such as dipropylene glycol; and one or more selected from diols such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, diphenylmethane 4,4′-dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, hetic acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, One or more selected from dicarboxylic acids such as hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid, and anhydrides thereof may be mentioned.
Specifically, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene hexamethylene adipate diol, Polydiethylene adipate diol, poly(polytetramethylene ether) adipate diol, poly(3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol, polyneo pentyl terephthalate diol and the like.

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

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

Aromatic polyisocyanates, aliphatic polyisocyanates, alicyclic polyisocyanates, and the like are examples of polyvalent isocyanates that are raw materials for urethane prepolymers (UP).
These polyvalent isocyanates may be used alone or in combination of two or more.
Further, these polyvalent isocyanates may be trimethylolpropane adduct-type modified products, biuret-type modified products reacted with water, and isocyanurate-type modified products containing an isocyanurate ring.
Among these, diisocyanates are preferred as the polyvalent isocyanate used in the present embodiment, and 4,4'-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tri More preferably, one or more selected from diisocyanate (2,6-TDI), hexamethylene diisocyanate (HMDI), and alicyclic diisocyanate.

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

In the present embodiment, the urethane prepolymer (UP) that forms the main chain of the acrylic urethane resin (U1) is a linear urethane prepolymer that is a reaction product of diol and diisocyanate and has ethylenically unsaturated groups at both ends. Polymers are preferred.
As a method for introducing ethylenically unsaturated groups at both ends of the linear urethane prepolymer, an NCO group at the terminal of the linear urethane prepolymer obtained by reacting a diol and a diisocyanate compound, and a hydroxyalkyl (meth)acrylate and a method of reacting with.
Hydroxyalkyl (meth)acrylates include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxy Butyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like can be mentioned.

At least (meth)acrylic acid ester is included as the vinyl compound that becomes the side chain of the acrylic urethane resin (U1).
As the (meth)acrylic acid ester, one or more selected from alkyl (meth)acrylates and hydroxyalkyl (meth)acrylates is preferable, and it is more preferable to use alkyl (meth)acrylates and hydroxyalkyl (meth)acrylates together.
When alkyl (meth)acrylate and hydroxyalkyl (meth)acrylate are used in combination, the ratio of hydroxyalkyl (meth)acrylate to 100 parts by mass of alkyl (meth)acrylate is preferably 0.1 to 100 parts by mass, more It is preferably 0.5 to 30 parts by mass, more preferably 1.0 to 20 parts by mass, and even more preferably 1.5 to 10 parts by mass.

The number of carbon atoms in the alkyl group of the alkyl (meth)acrylate is preferably 1-24, more preferably 1-12, still more preferably 1-8, still more preferably 1-3.
Examples of hydroxyalkyl (meth)acrylates include the same hydroxyalkyl (meth)acrylates used for introducing ethylenically unsaturated groups to both ends of the linear urethane prepolymer described above.

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

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

The acrylic urethane resin (U1) used in this embodiment is obtained by mixing a urethane prepolymer (UP) and a vinyl compound containing a (meth)acrylic acid ester and polymerizing the two.
In the 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) and 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 even more preferably 35/65 in mass ratio. ~55/45.

[Olefin resin]
The olefin resin suitable as the resin contained in the resin composition (y1) is a polymer having at least structural units derived from an olefin monomer.
As the olefin monomer, α-olefins having 2 to 8 carbon atoms are preferable, and specific examples include ethylene, propylene, butylene, isobutylene, 1-hexene, and the like.
Among these, ethylene and propylene are preferred.

Specific olefin resins include, for example, ultra-low density polyethylene (VLDPE, density: 880 kg/m ³ or more and less than 910 kg/m ³ ), low density polyethylene (LDPE, density: 910 kg/m ³ or more and less than 915 kg/m ³ ), medium density polyethylene (MDPE, density: 915 kg/m ³ or more and less than 942 kg/m ³ ), high density polyethylene (HDPE, density: 942 kg/m ³ or more), polyethylene resin such as linear low density polyethylene; polypropylene resin (PP); polybutene resin (PB); ethylene-propylene copolymer; olefin elastomer (TPO); poly (4-methyl-1-pentene) (PMP); ethylene-vinyl acetate copolymer (EVA); -vinyl alcohol copolymer (EVOH); olefinic terpolymers such as ethylene-propylene-(5-ethylidene-2-norbornene);

In this embodiment, the olefin-based resin may be a modified olefin-based resin further subjected to one or more modifications selected from acid modification, hydroxyl group modification, and acrylic modification.

For example, the acid-modified olefin resin obtained by subjecting an olefin resin to acid modification is a modified polymer obtained by graft-polymerizing an unsaturated carboxylic acid or its anhydride to the above-described unmodified olefin resin. is mentioned.
Examples of unsaturated carboxylic acids or anhydrides thereof include maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, tetrahydrophthalic acid, aconitic acid, (meth)acrylic acid, maleic anhydride, and itaconic anhydride. , glutaconic anhydride, citraconic anhydride, aconitic anhydride, norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride and the like.
The unsaturated carboxylic acid or its anhydride may be used alone, or two or more of them may be used in combination.

The acrylic-modified olefin-based resin obtained by subjecting an olefin-based resin to acrylic modification includes modification obtained by graft-polymerizing an alkyl (meth)acrylate as a side chain to the above-described unmodified olefin-based resin that is the main chain. polymers.
The number of carbon atoms in the alkyl group of the above alkyl (meth)acrylate is preferably 1-20, more preferably 1-16, still more preferably 1-12.
Examples of the above alkyl (meth)acrylates include the same compounds as those that can be selected as the monomer (a1') described below.

Examples of the hydroxyl group-modified olefin resin obtained by modifying the olefin resin with hydroxyl groups include a modified polymer obtained by graft polymerizing a hydroxyl group-containing compound to the above-described unmodified olefin resin that is the main chain.
Examples of the above hydroxyl group-containing compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl hydroxyalkyl (meth)acrylates such as (meth)acrylate and 4-hydroxybutyl (meth)acrylate; and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

[Resins other than acrylic urethane resins and olefin resins]
In the present embodiment, the resin composition (y1) may contain a resin other than the acrylic urethane resin and the olefin resin as long as the effects of the present invention are not impaired.
Examples of such resins include vinyl resins such as polyvinyl chloride, polyvinylidene chloride and polyvinyl alcohol; polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; Coalescence; cellulose triacetate; polycarbonate; polyurethane not applicable to acrylic urethane resins; polysulfone; polyetheretherketone; polyethersulfone; polyphenylene sulfide; Fluorinated resins and the like are included.
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 20 parts by mass, with respect to 100 parts by mass of the total resin contained in the resin composition (y1). less than 10 parts by weight, more preferably less than 5 parts by weight, and even more preferably less than 1 part by weight.

The resin composition (y1) preferably contains expandable particles.
The pressure-sensitive adhesive sheet (A) contains expandable particles not in the pressure-sensitive adhesive layer but in the base material (Y1) having a high elastic modulus, so that the pressure-sensitive adhesive layer (X1 ) thickness, control of adhesive strength, viscoelastic modulus, etc., and the degree of freedom in design is improved. Thus, it is possible to suppress the positional deviation of the chips and the chipping of the chips. Furthermore, when the adhesive sheet (A) is used, the chips are placed on the adhesive surface of the adhesive layer (X1), so the substrate (Y1) containing expansive particles and the chips do not come into direct contact. . As a result, the residue derived from the expandable particles and part of the adhesive layer that has been greatly deformed are prevented from adhering to the chip, and the uneven shape formed on the adhesive layer is prevented from being transferred to the chip, thereby maintaining cleanliness. The chip can be used for the next step as it is.
A suitable content of expandable particles is as described above.

The resin composition (y1) may contain additives for base materials, if necessary, as long as the effects of the present invention are not impaired.
Examples of base material additives include ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, colorants, and the like. These base material additives may be used alone or in combination of two or more.
When these base additives are contained, the content of each base additive is preferably 0.0001 to 20 parts by mass with respect to 100 parts by mass of the resin in the resin composition (y1). , more preferably 0.001 to 10 parts by mass.

[Solvent-free resin composition (y1′)]
As one aspect of the resin composition (y1) used in the present embodiment, an oligomer having an ethylenically unsaturated group with a mass average molecular weight (Mw) of 50000 or less, an energy ray-polymerizable monomer, and the expandable particles described above are blended. and a solvent-free resin composition (y1′) containing no solvent.
The solvent-free resin composition (y1') does not contain a solvent, but the energy ray-polymerizable monomer contributes to the improvement of the plasticity of the oligomer.
The substrate (Y1) can be obtained by irradiating the coating film formed from the solventless resin composition (y1′) with energy rays.
The type, shape, and compounding amount (content) of the expandable particles to be blended in the solventless resin composition (y1′) are as described above.

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

As the oligomer, among the resins contained in the above resin composition (y1), those having an ethylenically unsaturated group with a mass average molecular weight (Mw) of 50000 or less may be used. UP) is preferred.
A modified olefin resin having an ethylenically unsaturated group may also be used as the oligomer.

The total content of the oligomer and the energy ray-polymerizable monomer in the solvent-free resin composition (y1′) is preferably 50 to 99 mass %, more preferably 60 to 95 mass %, still more preferably 65 to 90 mass %, still more preferably 70 to 85 mass %.

Energy beam-polymerizable monomers include, for example, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, cyclohexyl (meth)acrylate, adamantane ( Alicyclic polymerizable compounds such as meth) acrylate and tricyclodecane acrylate; Aromatic polymerizable compounds such as phenylhydroxypropyl acrylate, benzyl acrylate, and phenol ethylene oxide-modified acrylate; Examples include heterocyclic polymerizable compounds such as vinylpyrrolidone and N-vinylcaprolactam.
These energy ray-polymerizable monomers may be used alone or in combination of two or more.

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

In the present embodiment, the solventless resin composition (y1') preferably further contains a photopolymerization initiator.
By containing a photopolymerization initiator, the curing reaction can be sufficiently advanced even by irradiation with relatively low-energy energy rays.

Examples of photopolymerization initiators include 1-hydroxy-cyclohexyl-phenyl-ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzylphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyrol. nitrile, dibenzyl, diacetyl, 8-chloroanthraquinone and the like.
These photopolymerization initiators may be used alone or in combination of two or more.

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

From the viewpoint of improving the interlayer adhesion between the base material (Y1) and other layers to be laminated, the surface of the base material (Y1) is subjected to a surface treatment such as an oxidation method, a roughening method, a primer treatment, and an easy-adhesion treatment. may be applied. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromic acid treatment (wet), hot air treatment, ozone, and ultraviolet irradiation treatment. Examples of the roughening method include sandblasting, solvent treatment, and the like. are mentioned.

[Storage elastic modulus of substrate (Y1)]
The storage modulus E′(23) of the base material (Y1) at 23° C. is preferably 1.0×10 ⁶ Pa or more, more preferably 5.0×10 ⁶ to 5.0×10 ¹² Pa, still more preferably is 1.0×10 ⁷ to 1.0×10 ¹² Pa, more preferably 5.0×10 ⁷ to 1.0×10 ¹¹ Pa, still more preferably 1.0×10 ⁸ to 1.0× 10 ¹⁰ Pa. When the storage elastic modulus E' (23) of the substrate (Y1) is within the above range, it is possible to suppress the occurrence of positional displacement of the workpiece during dicing and positional displacement during chip transfer.
In addition, in this specification, the storage elastic modulus E' of the base material (Y1) at a predetermined temperature means a value measured by the method described in Examples.

When the substrate (Y1) is the expandable substrate (Y1-1) and contains thermally expandable particles as the expandable particles, the expandable substrate (Y1-1) at the expansion start temperature (t) of the thermally expandable particles Y1-1) preferably has a storage modulus E′(t) of 1.0×10 ⁷ Pa or less. As a result, at the temperature at which the thermally expandable particles are expanded, the expandable substrate (Y1-1) easily deforms following the volume expansion of the thermally expandable particles, and the adhesive surface of the adhesive layer (X1) is uneven. easier to form. This allows separation from the chip with a small external force.
From the above viewpoint, the storage elastic modulus E′(t) of the expandable base material (Y1-1) is more preferably 9.0×10 ⁶ Pa or less, more preferably 8.0×10 ⁶ Pa or less, and even more preferably 8.0×10 6 Pa or less. It is preferably 6.0×10 ⁶ Pa or less, more preferably 4.0×10 ⁶ Pa or less. In addition, from the viewpoint of suppressing the flow of the expanded thermally expandable particles, improving the shape retention of the unevenness formed on the adhesive surface of the adhesive layer (X1), and further improving the separability, the expandable base material ( The storage modulus E′(t) of Y1-1) is preferably 1.0×10 ³ Pa or more, more preferably 1.0×10 ⁴ Pa or more, and still more preferably 1.0×10 ⁵ Pa or more. be.

(Non-expandable base material (Y1'))
The adhesive sheet (A) may have an adhesive layer (X1) on one side of the expandable base material (Y1-1) and a non-expandable base material (Y1') on the other side. good.
The term "non-expandable substrate" used herein means that the volume change rate calculated from the following formula is less than 5% by volume when treated under conditions in which the expandable particles contained in the adhesive sheet (A) expand. defined as things.
Volume change rate (%) = (volume of the layer after treatment - volume of the layer before treatment) / volume of the layer before treatment x 100
The volume change rate (%) of the non-expandable substrate (Y1′) calculated from the above formula is preferably less than 2% by volume, more preferably less than 1% by volume, even more preferably less than 0.1% by volume, and more More preferably less than 0.01% by volume.
When the expandable particles are thermally expandable particles, the conditions for expanding the expandable particles are the conditions for heat treatment at the expansion start temperature (t) for 3 minutes.
The non-expandable substrate (Y1′) may contain expandable particles, but the smaller the content, the better. is typically less than 3% by weight, preferably less than 1% by weight, more preferably less than 0.1% by weight, even more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight, and the expansion It is most preferred that it contains no organic particles.

Examples of materials for forming the non-expandable base material (Y1′) include paper materials, resins, and metals.
Examples of the paper material include thin paper, medium quality paper, fine paper, impregnated paper, coated paper, art paper, parchment paper, glassine paper, and the like.
Examples of resins include polyolefin resins such as polyethylene and polypropylene; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyester resins such as butylene terephthalate and polyethylene naphthalate; polystyrene; acrylonitrile-butadiene-styrene copolymer; cellulose triacetate; polycarbonate; polyether sulfone; polyphenylene sulfide; polyimide-based resins such as polyetherimide and polyimide; polyamide-based resins; acrylic resins;
Examples of metals include aluminum, tin, chromium, and titanium.
These forming materials may be composed of one type, or two or more types may be used in combination.
As the non-expanding base material (Y1') using two or more kinds of forming materials in combination, a paper material laminated with a thermoplastic resin such as polyethylene, or a resin film or sheet containing a resin with a metal film formed on its surface. things, etc.
As a method for forming the metal layer, for example, the above metal is deposited by a PVD method such as vacuum deposition, sputtering, or ion plating, or a metal foil made of the above metal is attached using a general adhesive. and the like.

When the pressure-sensitive adhesive sheet (A) has a non-expandable base material (Y1′), the expansion of the expandable base material (Y1-1) and the non-expandable base material (Y1′) before expanding the expandable particles. The thickness ratio [(Y1-1)/(Y1')] is preferably 0.02-200, more preferably 0.03-150, still more preferably 0.05-100.

From the viewpoint of improving the interlayer adhesion between the non-expanding substrate (Y1′) and other layers to be laminated, when the non-expanding substrate (Y1′) contains a resin, the non-expanding substrate (Y1′) The surface of the substrate (Y1) may be subjected to a surface treatment such as an oxidation method or a roughening method, a primer treatment, or an adhesion-facilitating treatment, in the same manner as the base material (Y1).
When the non-expanding base material (Y1′) contains a resin, the resin composition (y1) may also contain the above base material additives.

(Adhesive layer (X1))
The adhesive layer (X1) is a layer having adhesiveness. The pressure-sensitive adhesive layer (X1) contains a pressure-sensitive adhesive resin and, if necessary, may contain pressure-sensitive adhesive additives such as a cross-linking agent, a tackifier, a polymerizable compound, and a polymerization initiator.

The adhesive force of the adhesive surface of the adhesive layer (X1) is preferably 0.1 to 10.0 N/25 mm, more preferably 0.2 to 8.0 N/25 mm at 23°C before the expandable particles expand. , more preferably 0.4 to 6.0 N/25 mm, still more preferably 0.5 to 4.0 N/25 mm. When the adhesive force is 0.1 N/25 mm or more, the workpiece can be sufficiently fixed, and displacement of the workpiece during dicing can be suppressed. On the other hand, when the adhesive strength is 10.0 N/25 mm or less, the chips can be easily separated with a slight force.
In addition, said adhesive force means the value measured by the method as described in an Example.

The storage shear modulus G'(23) of the pressure-sensitive adhesive layer (X1) is preferably 1.0×10 ⁴ to 1.0×10 ⁸ Pa, more preferably 5.0×10 ⁴ to 5 at 23° C. 0×10 ⁷ Pa, more preferably 1.0×10 ⁵ to 1.0×10 ⁷ Pa. When the storage shear modulus G' (23) of the pressure-sensitive adhesive layer (X1) is 1.0×10 ⁴ Pa or more, it is possible to prevent displacement of the chip when separating from the chip. On the other hand, when the storage shear elastic modulus G′ (23) of the pressure-sensitive adhesive layer (X1) is 1.0×10 ⁸ Pa or less, unevenness due to the expanded expandable particles is likely to be formed on the pressure-sensitive adhesive surface, and a small amount of force can be applied. Can be easily separated.
When the pressure-sensitive adhesive sheet (A) is a pressure-sensitive adhesive sheet having a plurality of pressure-sensitive adhesive layers, the storage shear modulus G' (23) of the pressure-sensitive adhesive layer to which the chip is attached is preferably within the above range, and the substrate ( It is preferable that the storage shear elastic modulus G' (23) of all the pressure-sensitive adhesive layers on the side of Y1) to which the chip is attached is within the above range.
In addition, in this specification, the storage shear modulus G' (23) of the pressure-sensitive adhesive layer (X1) means a value measured by the method described in Examples.

The thickness of the pressure-sensitive adhesive layer (X1) is determined from the viewpoint of exhibiting excellent adhesive strength, and the expansion of the expandable particles in the expandable base material due to heat treatment to form unevenness on the surface of the formed pressure-sensitive adhesive layer. From the viewpoint of facilitating the separation, the thickness is preferably 1 to 60 μm, more preferably 2 to 50 μm, still more preferably 3 to 40 μm, and even more preferably 5 to 30 μm.

The ratio of the thickness of the base material (Y1) to the thickness of the adhesive layer (X1) (base material (Y1)/adhesive layer (X1)) is, from the viewpoint of preventing chip displacement, at 23° C. It is preferably 0.2 or more, more preferably 0.5 or more, still more preferably 1.0 or more, and even more preferably 5.0 or more, and can be easily separated with a slight force when separating From the viewpoint of forming an adhesive sheet, it is preferably 1000 or less, more preferably 200 or less, still more preferably 60 or less, and even more preferably 30 or less.
The thickness of the pressure-sensitive adhesive layer (X1) means the value measured by the method described in Examples.

The adhesive layer (X1) can be formed from an adhesive composition (x1) containing an adhesive resin. Each component that can be contained in the pressure-sensitive adhesive composition (x1) is described below.

[Adhesive resin]
The adhesive resin, which is the material for forming the adhesive layer (X1), is preferably a polymer having adhesiveness by itself and a weight average molecular weight (Mw) of 10,000 or more. The mass average molecular weight (Mw) of the adhesive resin is more preferably 10,000 to 2,000,000, still more preferably 20,000 to 1,500,000, and still more preferably 30,000 to 1,000,000 from the viewpoint of improving adhesive strength.

Examples of adhesive resins include acrylic resins, urethane resins, rubber resins such as polyisobutylene resins, polyester resins, olefin resins, silicone resins, and polyvinyl ether resins.
These adhesive resins may be used alone or in combination of two or more.
In addition, when these adhesive resins are copolymers having two or more structural units, the form of the copolymer is not particularly limited, and may be block copolymers, random copolymers, and graft copolymers. Any polymer may be used.

The adhesive resin may be an energy ray-curable adhesive resin in which a polymerizable functional group is introduced into the side chain of the adhesive resin.
Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl group.
Moreover, although an ultraviolet-ray, an electron beam, etc. are mentioned as an energy ray, an ultraviolet-ray is preferable.

The content of the adhesive resin is preferably 30 to 99.99% by mass, more preferably 40 to 99.95% by mass, relative to the total amount (100% by mass) of the active ingredients of the adhesive composition (x1), More preferably 50 to 99.90% by mass, still more preferably 55 to 99.80% by mass, and even more preferably 60 to 99.50% by mass.
In the following description of this specification, "the content of each component with respect to the total amount of active ingredients of the pressure-sensitive adhesive composition" means "the content of each component in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is synonymous with

The adhesive resin exhibits excellent adhesive strength, and at the time of separation, it is easy to form unevenness due to the expansion of the expandable particles on the adhesive surface to improve the separability of the adhesive sheet. It preferably contains a resin.
The content of the acrylic resin in the adhesive resin is preferably 30 to 100% by mass, more preferably 50%, based on the total amount (100% by mass) of the adhesive resin contained in the adhesive composition (x1). ~100% by mass, more preferably 70 to 100% by mass, and even more preferably 85 to 100% by mass.

[Acrylic resin]
Examples of acrylic resins that can be used as adhesive resins include polymers containing structural units derived from alkyl (meth)acrylates having linear or branched alkyl groups, and (meth)acrylates having a cyclic structure. Examples include polymers containing structural units derived from alkyl (meth) acrylate (a1 ') (hereinafter also referred to as "monomer (a1 ')") derived from structural units (a1) and functional group-containing monomers (a2 ') (hereinafter also referred to as "monomer (a2')") is more preferably an acrylic copolymer (A1) having a structural unit (a2).

The number of carbon atoms in the alkyl group of the monomer (a1') is preferably 1 to 24, more preferably 1 to 12, still more preferably 2 to 10, and even more preferably 4 to 8, from the viewpoint of improving adhesive properties. is.
The alkyl group possessed by the monomer (a1') may be a straight-chain alkyl group or a branched-chain alkyl group.
Examples of the monomer (a1′) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl ( meth)acrylate, stearyl (meth)acrylate, and the like.
These monomers (a1') may be used alone or in combination of two or more.
Butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred as monomer (a1').
The content of the structural unit (a1) is preferably 50 to 99.9% by mass, more preferably 60 to 99.0% by mass, based on the total structural units (100% by mass) of the acrylic copolymer (A1). %, more preferably 70 to 97.0% by mass, and even more preferably 80 to 95.0% by mass.

Examples of functional groups possessed by the monomer (a2′) include hydroxyl groups, carboxyl groups, amino groups, epoxy groups and the like.
That is, examples of the monomer (a2′) include hydroxyl group-containing monomers, carboxy group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, and the like.
These monomers (a2') may be used alone or in combination of two or more.
Among these, hydroxyl group-containing monomers and carboxy group-containing monomers are preferable as the monomer (a2′).
Examples of hydroxyl group-containing monomers include the same hydroxyl group-containing compounds as described above.
Carboxy group-containing monomers include, for example, ethylenically unsaturated monocarboxylic acids such as (meth)acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid, and their anhydrides , 2-(acryloyloxy)ethyl succinate, 2-carboxyethyl (meth)acrylate and the like.
The content of the structural unit (a2) is preferably 0.1 to 40% by mass, more preferably 0.5 to 35% by mass, based on the total structural units (100% by mass) of the acrylic copolymer (A1). %, more preferably 1.0 to 30% by mass, and even more preferably 3.0 to 25% by mass.

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

Examples of the monomer (a3′) include olefins such as ethylene, propylene and isobutylene; halogenated olefins such as vinyl chloride and vinylidene chloride; diene monomers such as butadiene, isoprene and chloroprene; Having a cyclic structure such as benzyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, imide (meth)acrylate, etc. (Meth)acrylate; styrene, α-methylstyrene, vinyltoluene, 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 polymerizable functional groups introduced into side chains. The polymerizable functional group and the energy ray are as described above. The polymerizable functional group is an acrylic copolymer having the above-described structural units (a1) and (a2), and a substituent capable of bonding to the functional group of the structural unit (a2) of the acrylic copolymer. and a compound having a polymerizable functional group.
Examples of the compound include (meth)acryloyloxyethyl isocyanate, (meth)acryloylisocyanate, glycidyl (meth)acrylate, and the like.

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

[Crosslinking agent]
When the adhesive composition (x1) contains a functional group-containing adhesive resin such as the acrylic copolymer (A1) described above, it preferably further contains a cross-linking agent.
The cross-linking agent reacts with the adhesive resin having a functional group to cross-link the adhesive resins with each other using the functional group as a cross-linking starting point.
Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and metal chelate-based cross-linking agents.
These cross-linking agents may be used alone or in combination of two or more.
Among these cross-linking agents, isocyanate-based cross-linking agents are preferred from the viewpoints of increasing cohesive strength and improving adhesive strength, and from the viewpoint of availability and the like.
The content of the cross-linking agent is appropriately adjusted according to the number of functional groups possessed by the adhesive resin. More preferably 0.03 to 7 parts by mass, still more preferably 0.05 to 5 parts by mass.

[Tackifier]
The pressure-sensitive adhesive composition (x1) may further contain a tackifier from the viewpoint of further improving the adhesive strength.
As used herein, the term "tackifier" refers to a component that supplementarily improves the adhesive strength of the adhesive resin described above, and refers to an oligomer having a weight-average molecular weight (Mw) of less than 10,000. It is distinguished from the hard resin.
The weight average molecular weight (Mw) of the tackifier is preferably 400-10,000, more preferably 500-8,000, still more preferably 800-5,000.

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

The softening point of the tackifier is preferably 60 to 170°C, more preferably 65 to 160°C, still more preferably 70 to 150°C.
In addition, in this specification, the "softening point" of a tackifier means the value measured based on JISK2531.
The tackifiers may be used alone, or two or more of them having different softening points, structures, etc. may be used in combination. When two or more tackifiers are used, the weighted average of the softening points of the tackifiers preferably falls within the above range.

The content of the tackifier is preferably 0.01 to 65% by mass, more preferably 0.05 to 55% by mass, relative to the total amount (100% by mass) of the active ingredients of the adhesive composition (x1), More preferably 0.1 to 50% by mass, even more preferably 0.5 to 45% by mass, and even more preferably 1.0 to 40% by mass.

[Photopolymerization initiator]
In the present embodiment, when the pressure-sensitive adhesive composition (x1) contains an energy ray-curable pressure-sensitive adhesive resin as the pressure-sensitive adhesive resin, it preferably further contains a photopolymerization initiator.
By making the adhesive composition containing an energy ray-curable adhesive resin and a photopolymerization initiator, the curing reaction is sufficiently advanced even by irradiation with relatively low-energy energy rays, and the desired adhesive strength is obtained. It is possible to adjust the range.
As the photopolymerization initiator, the same ones as those blended in the solventless resin composition (y1) can be mentioned.
The content of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, still more preferably 0.01 to 10 parts by mass, with respect to 100 parts by mass of the energy ray-curable adhesive resin. 05 to 2 parts by mass.

[Additive for adhesive]
In the present embodiment, the pressure-sensitive adhesive composition (x1), which is the material for forming the pressure-sensitive adhesive layer (X1), is used for general pressure-sensitive adhesives in addition to the additives described above, as long as the effects of the present invention are not impaired. It may contain additives for pressure-sensitive adhesives.
Examples of such adhesive additives include antioxidants, softeners (plasticizers), rust inhibitors, pigments, dyes, retarders, reaction accelerators (catalysts), and ultraviolet absorbers.
In addition, these additives for pressure-sensitive adhesives may be used alone, respectively, or two or more of them may be used in combination.
When these adhesive additives are contained, the content of each adhesive additive is preferably 0.0001 to 20 parts by mass, more preferably 0.001, per 100 parts by mass of the adhesive resin. ~10 parts by mass.
The adhesive layer (X1) may contain expandable particles. The content is preferably 5 parts by mass or less, more preferably 2 parts by mass or less, and most preferably not contained with respect to 100 parts by mass of the adhesive resin.

(Release material)
As the optionally used release material, a release sheet subjected to double-sided release treatment, a release sheet subjected to single-sided release treatment, and the like are used.
Examples of substrates for the release material include papers such as fine paper, glassine paper, and kraft paper; polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin; plastic films such as olefin resin films; and the like.
Examples of release agents include rubber-based elastomers such as silicone-based resins, olefin-based resins, isoprene-based resins and butadiene-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and the like.
Although the thickness of the release material is not particularly limited, it is preferably 10 to 200 μm, more preferably 25 to 170 μm, still more preferably 35 to 80 μm.

<Method for producing adhesive sheet (A)>
The method for producing the pressure-sensitive adhesive sheet (A) is not particularly limited, and examples thereof include production method (I) having the following steps (Ia) and (Ib).
Step (Ia): The resin composition (y1), which is the material for forming the base material (Y1), is applied onto the release-treated surface of the release material to form a coating film, and the coating film is dried or UV-cured, A step of forming a base material (Y1).
Step (Ib): The pressure-sensitive adhesive composition (x1), which is the material for forming the pressure-sensitive adhesive layer (X1), is applied to the surface of the formed substrate (Y1) to form a coating film, and the coating film is dried. and forming an adhesive layer (X1).

Another method for producing the pressure-sensitive adhesive sheet (A) includes, for example, production method (II) having the following steps (IIa) to (IIc).
Step (IIa): The resin composition (y1), which is the material for forming the substrate (Y1), is applied onto the release-treated surface of the release material to form a coating film, and the coating film is dried or UV-cured, A step of forming a base material (Y1).
Step (IIb): The pressure-sensitive adhesive composition (x1), which is the material for forming the pressure-sensitive adhesive layer (X1), is applied to the release-treated surface of the release material to form a coating film, and the coating film is dried and adhered. A step of forming an agent layer.
Step (IIc): A step of bonding the surface of the substrate (Y1) formed in step (IIa) and the surface of the adhesive layer (X1) formed in step (IIb).

In the production methods (I) and (II) above, the resin composition (y1) and the pressure-sensitive adhesive composition (x1) may be mixed with a diluent solvent to form a solution.
Examples of coating methods include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating.

The drying or UV irradiation in the manufacturing method (I) and the manufacturing method (II) is preferably carried out by appropriately selecting conditions under which the expandable particles do not expand. For example, when the resin composition (y1) containing thermally expandable particles is dried to form the substrate (Y1), the drying temperature is preferably lower than the expansion initiation temperature (t) of the thermally expandable particles. .
Further, when the pressure-sensitive adhesive sheet (A) has an expandable base material (Y1-1) and a non-expandable base material (Y1'), the resin composition (y1 ) may be applied onto a pre-formed non-expandable substrate (Y1'). The non-expandable base material (Y') is formed, for example, by using a resin composition that is the material for forming the non-expandable base material (Y') and performing the same operations as in steps (Ia) and (IIa). be able to.

[Method for manufacturing a semiconductor device according to the present embodiment]
Next, each step of the method for manufacturing the semiconductor device according to this embodiment will be described.
The method for manufacturing a semiconductor device according to this embodiment has the following steps (1) to (3) in this order.
Step (1): After attaching a workpiece to the adhesive layer (X1) of the adhesive sheet (A), the workpiece is diced and a plurality of individualized chips are formed on the adhesive layer (X1). The process of obtaining
Step (2): Using an adhesive sheet (B) having a substrate (Y2) and an adhesive layer (X2), on the surface opposite to the surface in contact with the adhesive layer (X1) of the plurality of chips, A step of attaching the adhesive layer (X2) of the adhesive sheet (B).
Step (3): A step of expanding the expandable particles to separate the plurality of chips attached to the adhesive sheet (B) from the adhesive sheet (A).
An example of using a semiconductor wafer as a workpiece will be described below with reference to the drawings.

<Step (1)>
In FIGS. 2(a) and (b), after affixing a semiconductor wafer W to the adhesive layer (X1) of the adhesive sheet (A), the semiconductor wafer W is diced, and individual pieces are formed on the adhesive layer (X1). A cross-sectional view for explaining the step (1) of obtaining a plurality of separated semiconductor chips CP is shown.

The semiconductor wafer W may be, for example, a silicon wafer or a compound semiconductor wafer such as gallium or arsenic.
A semiconductor wafer W has circuits W2 on its circuit surface W1. Examples of methods for forming the circuit W2 include an etching method and a lift-off method. In this specification, the surface opposite to the circuit surface W1 may be referred to as "chip rear surface".
The semiconductor wafer W is preliminarily ground to a predetermined thickness and attached to the adhesive sheet (A) with the rear surface of the chip exposed. As a method of grinding the semiconductor wafer W, for example, a known method using a grinder or the like can be used.
A ring frame may be attached to the adhesive sheet (A) for the purpose of holding the semiconductor wafer W thereon. In this case, the ring frame and the semiconductor wafer W are placed on the adhesive layer (X1) of the adhesive sheet (A) and lightly pressed to fix them.
Next, the semiconductor wafer W held by the adhesive sheet (A) is diced into individual pieces to form a plurality of semiconductor chips CP. For dicing, a cutting means such as a dicing saw, laser, plasma dicing, stealth dicing, or the like is used. The cutting depth during dicing may be appropriately set in consideration of the thickness of the semiconductor wafer.
Note that this process may be referred to as a "first dicing process" in order to distinguish it from another dicing process described later.
The step (1) may include a process of stretching the adhesive sheet (A) after dicing the semiconductor wafer W, in order to widen the intervals between the obtained plurality of semiconductor chips CP.

<Step (2)>
In FIG. 3, using an adhesive sheet (B) having a substrate (Y2) and an adhesive layer (X2), a plurality of semiconductor chips CP are coated on the surface opposite to the surface in contact with the adhesive layer (X1). , a cross-sectional view for explaining the step (2) of attaching the adhesive layer (X2) of the adhesive sheet (B).

The aspect of the pressure-sensitive adhesive sheet (B) may be appropriately determined depending on the subsequent steps. For example, when an expanding step for widening the space between a plurality of semiconductor chips CP is performed as a step subsequent to the first dicing step, an adhesive sheet for expansion (hereinafter also referred to as "expanding tape") is used as the adhesive sheet (B). should be used. On the other hand, in consideration of the workability of the subsequent processes, a reversing process for reversing the front and back sides of the plurality of semiconductor chips CP (that is, the circuit surface W1 and the chip back surface) is performed between the first dicing process and the expanding process. For implementation, an adhesive sheet for reversal (hereinafter also referred to as "adhesive sheet for reversal") may be used.
FIG. 3 shows an example of using a reversible pressure-sensitive adhesive sheet as the pressure-sensitive adhesive sheet (B).
Next, aspects of the pressure-sensitive adhesive sheet (B) suitable as the reversing pressure-sensitive adhesive sheet and the expanding tape will be described.

(Reversing adhesive sheet)
The reversal pressure-sensitive adhesive sheet has a substrate (Y2) and a pressure-sensitive adhesive layer (X2), and after the plurality of semiconductor chips CP are transferred from the pressure-sensitive adhesive sheet (A), the plurality of semiconductor chips CP are further transferred to another It is used to reverse the surface of the semiconductor chip CP that is in contact with the adhesive layer by transferring it to the adhesive sheet.
The reversal pressure-sensitive adhesive sheet is not particularly limited as long as it can achieve the above purpose, but since it is necessary to be able to be attached and separated from the semiconductor chip, an adhesive containing expandable particles such as the pressure-sensitive adhesive sheet (A) A sheet, an adhesive sheet having an adhesive layer composed of a non-energy ray-curable adhesive having removability, such as an expandable tape to be described later, an adhesive having an adhesive layer composed of an energy ray-curable adhesive A sheet or the like is suitable.
The substrate (Y2) of the pressure-sensitive adhesive sheet for reversal can be formed using the material for forming the substrate (Y1) of the pressure-sensitive adhesive sheet (A). Further, the pressure-sensitive adhesive layer (X2) of the reversing pressure-sensitive adhesive sheet can be formed using a material for forming the pressure-sensitive adhesive layer (X1) or the pressure-sensitive adhesive layer (X2) of the expandable tape described later. .
When the adhesive sheet (A) is used as the adhesive sheet (B), the aspect of the adhesive sheet (A) used in step (1) and the aspect of the adhesive sheet (A) used in this step are the same. may be different.

The thickness of the substrate (Y2) of the reversible pressure-sensitive adhesive sheet is preferably 10-1000 μm, more preferably 20-500 μm, even more preferably 25-400 μm, still more preferably 30-300 μm.
The thickness of the pressure-sensitive adhesive layer (X2) of the reversible pressure-sensitive adhesive sheet is preferably 1-60 μm, more preferably 2-50 μm, even more preferably 3-40 μm, and even more preferably 5-30 μm.

(expand tape)
Next, the adhesive sheet (B) suitable as an expanded tape will be described.
The expanding tape has a base material (Y2) and an adhesive layer (X2), and after transferring a plurality of semiconductor chips CP from the adhesive sheet (A) onto the adhesive layer (X2), the plurality of semiconductor chips CP are transferred to the adhesive layer (X2). It is used to stretch the adhesive sheet (B) to widen the space between the chips CP.

Materials for the base material (Y2) of the expanded tape include, for example, polyvinyl chloride resin, polyester resin (polyethylene terephthalate, etc.), acrylic resin, polycarbonate resin, polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene resin, polyimide resin, Examples include polyurethane resins and polystyrene resins.
The base material (Y2) of the expanded tape preferably contains a thermoplastic elastomer, a rubber-based material, or the like, and more preferably contains a thermoplastic elastomer.
Examples of thermoplastic elastomers include urethane-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, polyester-based elastomers, styrene-based elastomers, acrylic-based elastomers, and amide-based elastomers.

The base material (Y2) of the expanded tape may be a laminate of a plurality of films made of the above materials, or may be a laminate of a film made of the above materials and another film.
The base material (Y2) of the expanded tape contains various additives such as pigments, dyes, flame retardants, plasticizers, antistatic agents, lubricants, fillers, etc. in a film mainly made of the above resin material. may

The adhesive layer (X2) of the expanded tape may be composed of a non-energy ray-curable adhesive, or may be composed of an energy ray-curable adhesive.
As the non-energy ray-curable adhesive, those having desired adhesive strength and removability are preferable, and examples thereof include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, and polyester adhesives. , polyvinyl ether-based adhesives, and the like. Among these, acrylic pressure-sensitive adhesives are preferable from the viewpoint of effectively suppressing the falling off of semiconductor chips and the like when the pressure-sensitive adhesive sheet (B) is stretched.

Since the energy ray-curable adhesive is cured by energy ray irradiation and its adhesive strength is lowered, the semiconductor chip and the adhesive sheet (B) can be easily separated by irradiating them with the energy ray. .
Energy ray-curable adhesives constituting the adhesive layer (X2) of the expanded tape include, for example, (a) a polymer having energy ray-curable properties and (b) having at least one or more energy ray-curable groups. Examples include those containing one or more selected from monomers and/or oligomers.
(a) As the energy ray-curable polymer, a (meth)acrylic acid ester (co)polymer having an energy ray-curable functional group such as an unsaturated group (energy ray-curable group) introduced into the side chain coalescence is preferred. The acrylic ester (co)polymer includes, for example, an alkyl (meth)acrylate having an alkyl group having 1 to 18 carbon atoms, a polymerizable double bond, a hydroxy group, a carboxy group, an amino group, a substituted Examples include those obtained by copolymerizing a monomer having a functional group such as an amino group or an epoxy group in the molecule, and then reacting an unsaturated group-containing compound having a functional group that binds to the functional group. be done.
(b) Monomers and/or oligomers having at least one energy ray-curable group include esters of polyhydric alcohols and (meth)acrylic acid, specifically cyclohexyl (meth)acrylate, monofunctional acrylates such as isobornyl (meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1 Polyfunctional acrylates such as ,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, etc. , polyester oligo(meth)acrylate, polyurethane oligo(meth)acrylate and the like.
In addition to the components described above, the energy ray-curable pressure-sensitive adhesive may optionally contain a photopolymerization initiator, a cross-linking agent, and the like.

The thickness of the base material (Y2) of the expanded tape is not particularly limited, but is preferably 20-250 μm, more preferably 40-200 μm.
The thickness of the adhesive layer (X2) of the expanded tape is not particularly limited, but is preferably 3-50 μm, more preferably 5-40 μm.

The breaking elongation of the expanded tape measured in the MD direction and the CD direction at 23° C. is preferably 100% or more. When the elongation at break is within the above range, it is possible to extend the film to a large extent. Therefore, it can be suitably used for applications such as the manufacture of fan-out type packages, where it is necessary to sufficiently separate semiconductor chips from each other.

When the pressure-sensitive adhesive layer (X2) of the pressure-sensitive adhesive sheet (B) is composed of an energy ray-curable pressure-sensitive adhesive, the expandable particles contained in the pressure-sensitive adhesive sheet (A) are thermally expandable particles. is preferred.

<Step (3)>
FIG. 4 shows a cross-sectional view for explaining the step (3) of expanding the expandable particles to separate the plurality of semiconductor chips CP from the adhesive sheet (A).
In this step, the expandable particles are expanded by heat, energy rays, etc., depending on the type thereof, to form unevenness on the adhesive surface (X1a) of the adhesive layer (X1), thereby increasing the adhesive surface ( The adhesive force between X1a) and the plurality of semiconductor chips CP is reduced to separate the adhesive sheet (A) from the plurality of semiconductor chips CP.

The method for expanding the expandable particles may be appropriately selected according to the type of the expandable particles. When the expandable particles are thermally expandable particles, they may be heated to a temperature equal to or higher than the expansion start temperature (t). . Here, the "temperature equal to or higher than the expansion start temperature (t)" is preferably "expansion start temperature (t) + 10°C" or higher and "expansion start temperature (t) + 60°C" or lower. t)+15° C.” or more and “expansion start temperature (t)+40° C.” or less. Specifically, depending on the type of the thermally expandable particles, for example, they may be expanded by heating in the range of 70 to 330°C.

The expansion of the expandable particles is preferably carried out in a state where the surface (Y1a) of the substrate (Y1) opposite to the pressure-sensitive adhesive layer (X1) is fixed. By fixing the surface (Y1a), the occurrence of unevenness on the surface (Y1a) side is physically suppressed, and unevenness is efficiently formed on the adhesive surface (X1a) side of the adhesive layer (X1). be able to. Any method can be adopted for the fixing. A method of fixing the surface (Y1a) of the substrate (Y1) using a suction table having a hard support on the surface (Y1a) of the substrate (Y1) via an arbitrary adhesive layer, double-sided adhesive sheet, etc. and the like.
The suction table has a decompression mechanism such as a vacuum pump, and fixes the target on the suction surface by sucking the target through a plurality of suction holes with the decompression mechanism.
The material of the hard support may be appropriately determined in consideration of mechanical strength, heat resistance, etc. Examples include metallic materials such as SUS; non-metallic inorganic materials such as glass and silicon wafers; epoxy, ABS, acrylic, Resin materials such as engineering plastics, super engineering plastics, polyimides and polyamideimides; composite materials such as glass epoxy resins; among these, SUS, glass, silicon wafers and the like are preferred. Engineering plastics include nylon, polycarbonate (PC), polyethylene terephthalate (PET), and the like. Super engineering plastics include polyphenylene sulfide (PPS), polyethersulfone (PES), polyetheretherketone (PEEK), and the like.

<Expanding process>
Next, an expanding step is performed to widen the intervals between the plurality of semiconductor chips CP obtained above.
The expanding step includes the following step (4A) or steps (4B-1) to (4B-3) (hereinafter also referred to as “step (4B)” after step (3), depending on the aspect of the pressure-sensitive adhesive sheet (B). ) can be implemented.

Step (4A): A step in which the adhesive sheet (B) is an adhesive sheet for expansion, and the adhesive sheet for expansion is stretched to widen the gaps between the plurality of semiconductor chips attached to the adhesive sheet (B).

Step (4B-1): On the surface of the adhesive sheet (B) opposite to the surface in contact with the adhesive layer (X2) of the plurality of semiconductor chips, the adhesive layer (C) of the adhesive sheet (C), which is an expanded tape, is applied. The step of attaching X3).
Step (4B-2): A step of separating the adhesive sheet (B) from the plurality of semiconductor chips CP attached to the adhesive sheet (C).
Step (4B-3): A step of stretching the adhesive sheet for expansion to widen the gaps between the plurality of semiconductor chips attached to the adhesive sheet (C).

Step (4A) is a case where the adhesive sheet (B) used in step (2) is an expandable tape. good.

Step (4B) is a case where the pressure-sensitive adhesive sheet (B) is a reversing pressure-sensitive adhesive sheet, and a plurality of adhesive sheets are attached from the pressure-sensitive adhesive sheet (B), which is a pressure-sensitive adhesive sheet for reversing, to the pressure-sensitive adhesive sheet (C), which is a pressure-sensitive adhesive sheet for expansion. After transferring the semiconductor chip CP, it is a step of expanding.
In this embodiment, step (4B) will be described.

In FIGS. 5A and 5B, an expanding tape is applied to the surface opposite to the surface in contact with the adhesive layer (X2) of the plurality of semiconductor chips CP on the adhesive sheet (B), which is an adhesive sheet for reversing. A cross-sectional view showing a step (4B-1) of attaching the adhesive layer (X3) of the adhesive sheet (C), and then a step (4B-2) of separating the adhesive sheet (B) from the plurality of semiconductor chips CP. It is shown.
The method of separating the adhesive sheet (B) from the plurality of semiconductor chips CP may be appropriately selected according to the type of the adhesive sheet (B). When the pressure-sensitive adhesive layer (X2) is composed of a curable adhesive, it can be removed again under predetermined conditions. It should be separated after reducing the adhesive force.
Preferred aspects of the expanded tape are as described above.

FIGS. 6A and 6B illustrate the step (4B-3) of stretching the adhesive sheet (C) to widen the gaps between the plurality of semiconductor chips CP attached to the adhesive sheet for expansion (C). A cross-sectional view is shown.
Through the above steps, as shown in FIG. 6A, the multiple semiconductor chips CP are placed on the adhesive layer (X3) of the adhesive sheet (C).
Next, as shown in FIG. 6B, the adhesive sheet (C) is stretched to widen the distance D between the plurality of semiconductor chips CP.
As a method of stretching the adhesive sheet (C), a method of stretching the adhesive sheet (C) by pressing an annular or circular expander, or a method of gripping the outer peripheral portion of the adhesive sheet (C) using a gripping member or the like and stretching it. etc.
The distance D between the plurality of semiconductor chips CP after expansion may be appropriately determined according to the form of the desired semiconductor device, and is preferably 50 to 6000 μm.

<Steps (5) to (8)>
The method for manufacturing a semiconductor device according to the present embodiment uses an adhesive sheet (D) having a substrate (Y4) and an adhesive layer (X4), and further performs the following steps (5) to (8). may
Step (5): A step of transferring the plurality of semiconductor chips CP spaced apart in the expanding step to the adhesive layer (X4) of the adhesive sheet (D).
Step (6): Covering the plurality of semiconductor chips CP and the peripheral portions of the plurality of semiconductor chips CP on the adhesive surface of the adhesive layer (X4) with a sealing material, and curing the sealing material. a step of obtaining a hardened sealed body in which the semiconductor chip is sealed with a hardened sealing material;
Step (7): A step of separating the pressure-sensitive adhesive sheet (D) from the cured encapsulant.
Step (8): A step of forming a rewiring layer on the cured sealing body from which the pressure-sensitive adhesive sheet (D) has been separated.
However, the adhesive sheet (C), which is an expanded tape, may be used as the adhesive sheet (D), in which case step (5) is not required. In this case, the adhesive sheet (D) described below means the adhesive sheet (C).
Steps (5) to (8) will be described in order below.

[Step (5)]
Step (5) is a step of transferring the plurality of semiconductor chips CP spaced apart in the expanding step to the adhesive layer (X4) of the adhesive sheet (D).
In FIGS. 7A and 7B, an adhesive sheet (D) is applied to the surface opposite to the surface in contact with the adhesive layer (X3) of the plurality of semiconductor chips CP on the adhesive sheet for expansion (C). A cross-sectional view showing a step of separating the adhesive sheet (C) from the plurality of semiconductor chips CP after attaching the adhesive layer (X4) is shown.
Here, the adhesive sheet (D) is to be separated from the cured sealed body after sealing a plurality of semiconductor chips CP on its adhesive surface (X4a) to obtain a cured sealed body. . Therefore, in the adhesive sheet (D), the position of the semiconductor chip does not shift during sealing with the sealing material, and the sealing material does not enter the adhesive interface between the semiconductor chip and the temporary fixing sheet. A degree of adhesion is required, and separability that can be easily removed after sealing is required.
The adhesive sheet (D) is not particularly limited as long as it can achieve the above purpose. A pressure-sensitive adhesive sheet containing the adhesive, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of a non-energy ray-curable pressure-sensitive adhesive having removability, and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of an energy ray-curable pressure-sensitive adhesive are suitable. . Among these, it is preferable to use the pressure-sensitive adhesive sheet (A) from the viewpoint of achieving both excellent adhesiveness and separability.
When the adhesive sheet (A) is used as the adhesive sheet (D), the aspect of the adhesive sheet (A) used in step (1) and the aspect of the adhesive sheet (A) used in this step are the same. may be different.

In this step, the method of separating the adhesive sheet (C) and the plurality of semiconductor chips CP may be determined according to the form of the adhesive sheet (C), as in the case of the adhesive sheet (B).

[Step (6)]
8A to 8C, the plurality of semiconductor chips CP and the peripheral portions 45 of the plurality of semiconductor chips CP on the adhesive surface (X4a) of the adhesive layer (X4) are sealed with the sealing material 40. covering (hereinafter also referred to as a “coating step”) and curing the sealing material 40 (hereinafter also referred to as a “curing step”) so that the plurality of semiconductor chips CP are cured sealing material 41 A cross-sectional view for explaining the step (6) of obtaining a cured sealing body 50 sealed in the .

The sealing material 40 has a function of protecting the plurality of semiconductor chips CP and their associated elements from the external environment. The encapsulating material 40 is not particularly limited, and can be appropriately selected and used from those conventionally used as semiconductor encapsulating materials.
The encapsulating material 40 has curable properties from the viewpoint of mechanical strength, heat resistance, insulating properties, etc. Examples thereof include thermosetting resin compositions and energy ray curable resin compositions.
Examples of the thermosetting resin contained in the thermosetting resin composition that is the sealing material 40 include epoxy resin, phenol resin, and cyanate resin. Epoxy resin is preferable from the viewpoint of the above.
In addition to the thermosetting resin, the thermosetting resin composition may optionally include a curing agent such as a phenolic resin curing agent and an amine curing agent, a curing accelerator, an inorganic filler such as silica, Additives such as elastomers may be contained.
The sealing material 40 may be solid or liquid at room temperature. Moreover, the form of the sealing material 40 which is solid at room temperature is not particularly limited, and may be, for example, a granular form, a sheet form, or the like.
In the present embodiment, it is preferable to use a sheet-like sealing material (hereinafter also referred to as "sheet-like sealing material") to perform the covering step and the curing step. In the method using a sheet-like sealing material, the sheet-like sealing material is placed so as to cover the plurality of semiconductor chips CP and their peripheral portions 45, thereby covering the plurality of semiconductor chips CP and their peripheral portions 45 with the sealing material. 40. At this time, it is preferable to heat and pressure-bond the plurality of semiconductor chips CP while appropriately reducing the pressure by a vacuum lamination method or the like so that there is no portion where the sealing material 40 is not filled in the gaps between the plurality of semiconductor chips CP.

As a method for covering the plurality of semiconductor chips CP and their peripheral portions 45 with the encapsulant 40, an arbitrary method may be appropriately selected and applied from conventional methods applied to the semiconductor encapsulation process. For example, a roll lamination method, a vacuum press method, a vacuum lamination method, a spin coating method, a die coating method, a transfer molding method, a compression molding method, or the like can be applied.
In these methods, the sealing material 40 is usually heated at the time of coating to impart fluidity in order to improve the filling properties of the sealing material 40 .
The temperature for heating the thermosetting resin composition in the coating step varies depending on the type of the sealing material 40, the type of the adhesive sheet (D), etc., but is, for example, 30 to 180°C, and 50 to 170°C. Preferably, 70 to 150°C is more preferable. The heating time is, for example, 5 seconds to 60 minutes, preferably 10 seconds to 45 minutes, more preferably 15 seconds to 30 minutes.

As shown in FIG. 8B, the sealing material 40 covers the entire exposed surfaces of the plurality of semiconductor chips CP and also fills the gaps between the plurality of semiconductor chips CP.

Next, as shown in FIG. 8C, after performing a coating step, the sealing material 40 is cured to obtain a cured sealing body in which a plurality of semiconductor chips CP are sealed with the cured sealing material 41. Get 50.
In the curing step, the temperature for curing the encapsulating material 40 varies depending on the type of the encapsulating material 40, the type of the adhesive sheet (D), etc., but is, for example, 80 to 240°C, preferably 90 to 200°C. , 100 to 170° C. is more preferable. The heating time is, for example, 10 to 180 minutes, preferably 20 to 150 minutes, more preferably 30 to 120 minutes.
Through the step (6), the cured sealing body 50 in which the plurality of semiconductor chips CP separated by a predetermined distance are embedded in the cured sealing material 41 is obtained.

[Step (7)]
Next, as shown in FIG. 8(d), the adhesive sheet (D) is separated from the cured sealant 50. Next, as shown in FIG.
The method for separating the pressure-sensitive adhesive sheet (D) may be appropriately selected according to the type of the pressure-sensitive adhesive sheet (D). When the adhesive sheet (A) is used as the adhesive sheet (D), it can be separated from the cured sealing body 50 by expanding the expandable particles contained in the adhesive sheet (A). The conditions for expanding the expandable particles are as described for the pressure-sensitive adhesive sheet (A).

In this embodiment, the circuit surface W1 of the plurality of semiconductor chips CP is described as an example in which the sealing step is performed while being in contact with the adhesive layer (X4) of the adhesive sheet (D). The sealing step may be performed in an exposed state (that is, a state in which the back surface of the chip is in contact with the adhesive layer (X4)). In this case, the circuit surfaces W1 of the plurality of semiconductor chips CP are covered with the sealing resin. What is necessary is just to expose the circuit surface W1.

[Step (8)]
9A to 9C are cross-sectional views illustrating the step (8) of forming a rewiring layer on the cured sealing body 50 from which the adhesive sheet (D) has been separated.
FIG. 9B shows a cross-sectional view for explaining the step of forming the first insulating layer 61 on the circuit surface W1 of the semiconductor chip CP and the surface 50a of the hardening sealing body 50. As shown in FIG.
A first insulating layer 61 containing an insulating resin is formed on the circuit surface W1 and the surface 50a so as to expose the circuit W2 of the semiconductor chip CP or the internal terminal electrode W3 of the circuit W2. Examples of insulating resins include polyimide resins, polybenzoxazole resins, and silicone resins. 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. 9C shows a cross-sectional view for explaining the step of forming the rewiring 70 electrically connected to the semiconductor chip CP encapsulated in the cured encapsulant 50. As shown in FIG.
In this embodiment, the rewiring 70 is formed following the formation of the first insulating layer 61 . 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 can be formed by a known method such as a subtractive method or a semi-additive method.

FIG. 10A shows a cross-sectional view for explaining the step of forming the second insulating layer 62 covering the rewiring 70. As shown in FIG.
The rewiring 70 has external electrode pads 70A for external terminal electrodes. An opening or the like is provided in the second insulating layer 62 to expose the external electrode pad 70A for the external terminal electrode. In the present embodiment, the external electrode pads 70A are provided inside and outside the area (the area corresponding to the circuit surface W1) of the semiconductor chip CP of the cured sealing body 50 (the area corresponding to the surface 50a on the cured sealing body 50). exposed to Further, the rewiring 70 is formed on the surface 50a of the hardening sealing body 50 so that the external electrode pads 70A are arranged in an array. Since the present embodiment has a structure in which the external electrode pads 70A are exposed outside the region of the semiconductor chip CP of the cured sealing body 50, FOWLP or FOPLP can be obtained.

(Connection process with external terminal electrodes)
Next, external terminal electrodes 80 may be connected to the external electrode pads 70A, if necessary.
FIG. 10B shows a cross-sectional view for explaining the process of connecting the external terminal electrodes 80 to the external electrode pads 70A.
An external terminal electrode 80 such as a solder ball is placed on the external electrode pad 70A exposed from the second 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 and lead-free solder.

(Second dicing step)
FIG. 10(c) shows a cross-sectional view for explaining the second dicing step for singulating the cured sealing body 50 to which the external terminal electrodes 80 are connected.
In this step, the cured sealing body 50 is separated into individual semiconductor chips CP. A method for separating the cured sealant 50 into individual pieces is not particularly limited, and can be carried out by a cutting means such as a dicing saw.
By dividing the cured sealant 50 into individual pieces, the semiconductor device 100 for each semiconductor chip CP is manufactured. As described above, the semiconductor device 100 in which the external terminal electrodes 80 are connected to the external electrode pads 70A fanned out to the outside of the semiconductor chip CP is manufactured as FOWLP, FOPLP, or the like.

(Mounting process)
In this embodiment, it is also preferable to include a step of mounting the individualized semiconductor device 100 on a printed wiring board or the like.

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

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

<Measurement of thickness of each layer>
It was measured using a constant pressure thickness measuring instrument manufactured by Teclock Co., Ltd. (model number: “PG-02J”, standard specifications: JIS K6783, Z1702, Z1709).

<Average particle size ( _D50 ) and 90% particle size ( _D90 ) of thermally expandable particles>
The particle distribution of the thermally expandable particles before expansion at 23° C. was measured using a laser diffraction particle size distribution analyzer (eg, product name “Mastersizer 3000” manufactured by Malvern).
Then, the particle diameters corresponding to the cumulative volume frequencies of 50% and 90% calculated from the smaller particle diameter in the particle distribution are determined as the "average particle diameter of the thermally expandable particles (D ₅₀ )" and the "thermally expandable particles 90% particle size (D ₉₀ ).

<Storage elastic modulus E′ of expandable substrate>
When the object to be measured is a non-adhesive expandable substrate, the expandable substrate measures 5 mm long×30 mm wide×200 μm thick, and the release material is removed to obtain a test sample.
Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, product name “DMAQ800”), the test start temperature is 0 ° C., the test end temperature is 300 ° C., the temperature increase rate is 3 ° C./min, the frequency is 1 Hz, and the amplitude is 20 μm. The storage elastic modulus E' of the test sample was measured at a predetermined temperature under the conditions of .

<Storage shear modulus G′ of pressure-sensitive adhesive layer>
When the object to be measured is a pressure-sensitive adhesive layer having stickiness, the pressure-sensitive adhesive layer was 8 mm in diameter and 3 mm in thickness, and a test sample was obtained by removing the release material.
Using a viscoelasticity measuring device (manufactured by Anton Paar, device name "MCR300"), the torsional shear method was performed under the conditions of a test start temperature of 0 ° C., a test end temperature of 300 ° C., a temperature increase rate of 3 ° C./min, and a frequency of 1 Hz. measured the storage shear modulus G' of the test samples at a given temperature. Then, the value of the storage elastic modulus E' was calculated from the approximate expression "E'=3G'" based on the value of the measured storage shear elastic modulus G'.

<Probe tack value>
After cutting the expansible base material or adhesive layer to be measured into a square with a side of 10 mm, let it stand for 24 hours in an environment of 23 ° C. and 50% RH (relative humidity), and remove the light release film. used as a test sample.
The test sample is subjected to a tacking tester (manufactured by Nihon Tokushu Sokki Co., Ltd., product name "NTS-4800") in an environment of 23 ° C. and 50% RH (relative humidity) to remove the light release film. The probe tack value on the surface of the test sample, which was expressed by the test sample, was measured according to JIS Z0237:1991.
Specifically, a stainless steel probe with a diameter of 5 mm is brought into contact with the surface of the test sample for 1 second with a contact load of 0.98 N/cm ² , and then the probe is moved at a speed of 10 mm/second to the test sample. The force required to release from the surface was measured. The measured value was used as the probe tack value of the test sample.

The details of the adhesive resin, additive, thermally expandable particles, and release material used to form each layer in the following production examples are as follows.
<Adhesive resin>
-Acrylic copolymer (i): 2-ethylhexyl acrylate (2EHA)/2-hydroxyethyl acrylate (HEA) = 80.0/20.0 (mass ratio) having structural units derived from raw material monomers, A solution containing an acrylic copolymer of Mw 600,000. Dilution solvent: ethyl acetate, solid content concentration: 40% by mass.
<Additive>
· Isocyanate cross-linking agent (i): manufactured by Tosoh Corporation, product name "Coronate L", solid content concentration: 75% by mass.
· Photopolymerization initiator (i): manufactured by BASF, product name “Irgacure 184”, 1-hydroxy-cyclohexyl-phenyl-ketone.
<Thermal expandable particles>
- Thermally expandable particles (i): manufactured by Kureha Co., Ltd., product name "S2640", expansion start temperature (t) = 208°C, average particle size ( _D50 ) = 24 µm, 90% particle size ( _D90 ) = 49 µm .
<Release material>
· Heavy release film: manufactured by Lintec Corporation, product name "SP-PET382150", a polyethylene terephthalate (PET) film provided with a release agent layer formed from a silicone release agent on one side, thickness: 38 µm.
· Light release film: product name “SP-PET381031” manufactured by Lintec Corporation, a PET film provided with a release agent layer formed from a silicone release agent on one side, thickness: 38 μm.

Production example 1
(Formation of adhesive layer (X1))
5.0 parts by mass of the isocyanate cross-linking agent (i) (solid content ratio) is blended with 100 parts by mass of the solid content of the solution of the acrylic copolymer (i), which is an adhesive resin, and diluted with toluene. and uniformly stirred to prepare a pressure-sensitive adhesive composition (x1) having a solid content concentration (active ingredient concentration) of 25% by mass.
Then, on the surface of the release agent layer of the heavy release film, the prepared pressure-sensitive adhesive composition (x1) is applied to form a coating film, and the coating film is dried at 100 ° C. for 60 seconds to a thickness of 10 μm. to form a pressure-sensitive adhesive layer (X1). The storage shear modulus G'(23) of the pressure-sensitive adhesive layer (X1) at 23°C was 2.5 x ^105Pa .

Production example 2
(Formation of expandable substrate (Y1-1))
A terminal isocyanate urethane prepolymer obtained by reacting an ester diol and isophorone diisocyanate (IPDI) is reacted with 2-hydroxyethyl acrylate to obtain a bifunctional acrylic urethane oligomer having a mass average molecular weight (Mw) of 5000. Obtained.
Then, to 40% by mass (solid content ratio) of the acrylic urethane-based oligomer synthesized above, 40% by mass (solid content ratio) of isobornyl acrylate (IBXA) and phenylhydroxypropyl acrylate (HPPA) are added as energy ray-polymerizable monomers. ) 20% by mass (solid content ratio), and further photopolymerization initiator (i) 2.0 parts by mass (solid content ratio) with respect to 100 parts by mass of the total amount of acrylic urethane oligomer and energy ray polymerizable monomer and 0.2 parts by mass (solid content ratio) of a phthalocyanine pigment as an additive to prepare an energy ray-curable composition. The heat-expandable particles (i) were added to the energy ray-curable composition to prepare a solvent-free resin composition (y1) containing no solvent. The content of the thermally expandable particles (i) was 20% by mass with respect to the total amount (100% by mass) of the resin composition (y1).
Next, the prepared resin composition (y1) was applied onto the surface of the release agent layer of the light release film to form a coating film. Then, using an ultraviolet irradiation device (manufactured by Eyegraphics, product name “ECS-401GX”) and a high-pressure mercury lamp (manufactured by Eyegraphics, product name “H04-L41”), an illuminance of 160 mW/cm ² and a light intensity of 500 mJ/ The coating film was cured by irradiating with ultraviolet rays under the condition of cm ² to form an expandable base material (Y1-1) having a thickness of 50 μm. The above illuminance and light amount during ultraviolet irradiation are values measured using an illuminance/photometer (manufactured by EIT, product name “UV Power Puck II”).
The storage elastic modulus E' at 23°C of the expandable substrate (Y1-1) obtained above was 5.0 × 10 ⁸ Pa, and the storage elastic modulus E' at 100°C was 4.0 × 10. The storage modulus E′ at ⁶ Pa and 208° C. was 4.0×10 ⁶ Pa. In addition, the probe tack value of the expandable substrate (Y1-1) was 2 mN/5 mmφ.

Production example 3
(Preparation of adhesive sheet (A))
The surfaces of the pressure-sensitive adhesive layer (X1) formed in Production Example 1 and the expandable base material (Y1-1) formed in Production Example 2 were bonded together. As a result, an adhesive sheet (A) was prepared by laminating the light release film/expandable substrate (Y1-1)/adhesive layer (X1)/heavy release film in this order.

Production example 4
(Preparation of adhesive sheet (B) (expanded tape))
An acrylic copolymer obtained by reacting butyl acrylate/2-hydroxyethyl acrylate = 85/15 (mass ratio), and 80 mol% methacryloyloxyethyl isocyanate (MOI) with respect to 2-hydroxyethyl acrylate. were reacted to obtain an energy ray-curable polymer. The mass average molecular weight (Mw) of this energy ray-curable polymer was 600,000. 100 parts by mass of the obtained energy ray-curable polymer, 3 parts by mass of 1-hydroxycyclophenyl ketone (manufactured by BASF, product name “Irgacure 184”) as a photopolymerization initiator, and tolylene diisocyanate as a cross-linking agent. 0.45 parts by mass of a system crosslinking agent (manufactured by Tosoh Corporation, product name "Coronate L") was mixed in a solvent to obtain an adhesive composition.
Next, on the surface of the release agent layer of a release film (manufactured by Lintec Corporation, product name "SP-PET3811") in which a silicone-based release agent layer is formed on one side of a polyethylene terephthalate (PET) film, the above The adhesive composition was applied and dried by heating to form an adhesive layer (X2) having a thickness of 10 μm on the release film. After that, one side of a polyester-based polyurethane elastomer sheet (manufactured by Seedam Co., Ltd., product name “Higress DUS202”, thickness 50 μm) is laminated as a base material (Y2) to the exposed surface of the adhesive layer, thereby forming an adhesive layer. A pressure-sensitive adhesive sheet (B) (expanded tape) was obtained in a state in which the release film was attached to the surface.

[Manufacture of semiconductor devices]
Example 1
Using the pressure-sensitive adhesive sheet (A) and the pressure-sensitive adhesive sheet (B) obtained above, a semiconductor device was manufactured by the following method.
<Step (1)>
The pressure-sensitive adhesive sheet (A) obtained in Production Example 3 was cut into a size of 230 mm×230 mm.
Peel off the heavy release film and light release film from the cut adhesive sheet (A), and attach a ring frame and a semiconductor wafer (diameter: 150 mm, thickness: 350 μm) to the surface of the exposed adhesive layer (X1). did. Next, the semiconductor wafer was diced in a full cut using a dicer (manufactured by Disco, product name “DFD-651”) under the following conditions. As a result, a plurality of individualized semiconductor chips (1800 pieces) were obtained on the adhesive layer (X1) of the adhesive sheet (A).
・ Dicing blade: manufactured by Disco, product name “NBC-ZH2050 27HECC”
・Number of revolutions: 30,000 rpm
・Height: 0.06mm
・60mm/sec
・Chip size: 3mm x 3mm
<Step (2)>
Next, the adhesive sheet (B) obtained in Production Example 4 was cut into a size of 210 mm×210 mm. At this time, each side of the sheet after cutting was cut so as to be parallel or perpendicular to the MD direction of the substrate (Y2) of the pressure-sensitive adhesive sheet (B). Next, the release sheet is peeled off from the adhesive sheet (B), and the adhesive layer (X2) of the adhesive sheet (B) is applied to the surface opposite to the surface in contact with the adhesive layer (X1) of the plurality of semiconductor chips. affixed. At this time, a group of semiconductor chips was transferred so as to be positioned at the center of the adhesive sheet (B). Also, the dicing lines when the semiconductor wafer was singulated were transferred so as to be parallel or perpendicular to each side of the adhesive sheet (B).
<Step (3)>
Next, a hot plate is pressed against the surface of the expandable substrate (Y1-1) of the adhesive sheet (A) opposite to the adhesive layer (X), and the adhesive sheet (A) is thermally expanded. The thermally expandable particles are heated at 240° C. for 3 minutes, which is equal to or higher than the expansion start temperature (208° C.) of the thermally expandable particles, and the plurality of semiconductor chips and the adhesive sheet (A) are attached to the adhesive sheet (B). separated. When the adhesive sheet (A) was separated, the adhesive sheet (A) was separated from the plurality of semiconductor chips all at once while maintaining a flat shape without bending the adhesive sheet (A).
<Expanding process>
Subsequently, the pressure-sensitive adhesive sheet (B) having a plurality of semiconductor chips attached thereto was placed in an expanding device capable of biaxial stretching. As shown in FIG. 11, the expanding device is arranged in the X-axis direction (the positive direction is the +X-axis direction and the negative direction is the -X-axis direction) and the Y-axis direction (the positive direction is the +Y-axis direction) which are orthogonal to each other. , the negative direction is the -Y-axis direction), and has holding means for stretching in each direction (ie +X-axis direction, -X-axis direction, +Y-axis direction, -Y-axis direction). The MD direction of the adhesive sheet (B) is aligned with the X-axis or Y-axis direction, and the adhesive sheet (B) is placed in an expanding device, each side of the adhesive sheet (B) is held by the holding means, and then under the following conditions: , the adhesive sheet (B) was stretched to increase the distance between the plurality of semiconductor chips attached on the adhesive layer (X2) of the adhesive sheet (B).
・Number of holding means: 5 per side ・Stretching speed: 5 mm/sec
- Stretching distance: Each side was stretched by 60 mm.

Comparative example 1
<Step (1)>
A ring frame and a semiconductor wafer ( diameter: 150 mm, thickness: 350 μm). After that, in the same manner as the step (1) of Example 1, a plurality of singulated semiconductor chips were obtained.
<Step (2)>
It was carried out in the same manner as in Example 1.
<Step (3)>
The surface of the dicing tape for comparison on the base material side was irradiated with ultraviolet rays at an illuminance of 230 mW/cm ² and a light amount of 190 mJ/cm ² to cure the adhesive layer, and the plurality of semiconductor chips attached to the adhesive sheet (B). The dicing tape for comparison was separated. When separating the dicing tape for comparison, the dicing tape for comparison was separated from a plurality of semiconductor chips at the same time while maintaining a planar shape without bending the dicing tape for comparison.
<Expanding process>
It was carried out in the same manner as in Example 1.

[Evaluation of chip chipping]
The appearance of the plurality of semiconductor chips obtained above after being expanded was observed under a microscope to confirm the presence or absence of chip chipping of the semiconductor chips, and evaluation was made according to the following criteria.
A: There was a chip chip.
· F: There was no tip chipping.

[Measurement of adhesive strength of adhesive sheet]
(Measurement of adhesive strength before and after heating adhesive sheet (A))
The light release film of the produced adhesive sheet (A) was removed. Next, the heavy release film of the adhesive sheet (A) was also removed, and the exposed adhesive surface of the adhesive layer (X1) was attached to a stainless steel plate (SUS304, No. 360 polishing) as an adherend. A test sample was prepared by standing for 24 hours in an environment of 50% RH (relative humidity).
Using the above test sample, in an environment of 23 ° C. and 50% RH (relative humidity), based on JIS Z0237: 2000, by a 180 ° peeling method, at a pulling speed of 300 mm / min, adhesive strength at 23 ° C. was measured.
In addition, the above test sample is heated on a hot plate at 240 ° C., which is the expansion start temperature (208 ° C.) or higher of the thermally expandable particles, for 3 minutes, in a standard environment (23 ° C., 50% RH (relative humidity) ) for 60 minutes, and then under the same conditions as above, the adhesive strength after heating at the expansion start temperature or higher was also measured.

(Adhesive strength measurement of comparison dicing tape before and after UV irradiation)
The adhesive surface of a dicing tape for comparison (manufactured by Lintec Co., Ltd., product name "D-820") was attached to a stainless steel plate (SUS304, polished #360) as an adherend, and subjected to 23 ° C. and 50% RH (relative humidity). A test sample was prepared by standing for 24 hours under the environment of , and the adhesive strength at 23°C before ultraviolet irradiation was measured under the same conditions as for the adhesive sheet (A).
Next, after irradiating ultraviolet rays at an illuminance of 230 mW/cm ² and a light amount of 190 mJ/cm ² from the substrate side of the comparative dicing tape, the adhesive force at 23° C. after ultraviolet irradiation was measured under the same conditions as above.

From the results in Table 1, the pressure-sensitive adhesive sheet (A) used in the production method of the present embodiment has a lower adhesive strength after expansion than the conventional ultraviolet irradiation-type pressure-sensitive adhesive sheet, and is obtained by dicing a semiconductor wafer. It can be seen that a plurality of chips can be easily transferred to another adhesive sheet, and chip chipping during transfer can be effectively suppressed.

1a Adhesive sheet (a)
1b adhesive sheet (a)
40 sealing material 41 hardening sealing material 45 peripheral portion of semiconductor chip CP 50 hardening sealing body 50a surface 61 first insulating layer 62 second insulating layer 70 rewiring 70A external electrode pad 80 external terminal electrode 100 semiconductor device 200 expanding device 210 holding means CP semiconductor chip W1 circuit surface W2 circuit W3 internal terminal electrode

Claims (11)

A method for manufacturing a semiconductor device using an expandable adhesive sheet (A) having a substrate (Y1) and an adhesive layer (X1),
The base material (Y1) is an expandable base material (Y1-1) containing expandable particles,
The storage modulus E'(23) of the substrate (Y1) at 23°C is 1.0 × 10 ⁶ to 5.0 × 10 ¹² Pa,
A method for manufacturing a semiconductor device, comprising the following steps (1) to (3) in this order.
Step (1): After attaching a workpiece to the adhesive layer (X1) of the adhesive sheet (A), the workpiece is diced and a plurality of individualized chips are formed on the adhesive layer (X1). The process of obtaining
Step (2): Using an adhesive sheet (B) having a substrate (Y2) and an adhesive layer (X2), on the surface opposite to the surface in contact with the adhesive layer (X1) of the plurality of chips, A step of attaching the adhesive layer (X2) of the adhesive sheet (B).
Step (3): A step of expanding the expandable particles to separate the plurality of chips attached to the adhesive sheet (B) from the adhesive sheet (A). 2. The method of manufacturing a semiconductor device according to claim 1, wherein the adhesive sheet (B) is an adhesive sheet for expansion, and further comprises the following step (4A) after step (3).
Step (4A): A step of stretching the adhesive sheet (B) to widen the gaps between the plurality of chips attached to the adhesive sheet (B). The following steps (4B-1) to (4B-3) are further performed using the adhesive sheet (C) for expansion having the substrate (Y3) and the adhesive layer (X3), according to claim 1. A method of manufacturing a semiconductor device.
Step (4B-1): Attach the adhesive layer (X3) of the adhesive sheet (C) to the surface of the plurality of chips on the adhesive sheet (B) opposite to the surface in contact with the adhesive layer (X2). process.
Step (4B-2): A step of separating the adhesive sheet (B) from the plurality of chips attached to the adhesive sheet (C).
Step (4B-3): A step of stretching the adhesive sheet (C) to widen the gaps between the plurality of chips attached to the adhesive sheet (C). 4. The method of manufacturing a semiconductor device according to claim 2, wherein said adhesive sheet for expansion has a breaking elongation of 100% or more measured in the MD direction and the CD direction at 23[deg.]C. The expandable particles are thermally expandable particles having an expansion start temperature (t) of 60 to 270° C., and the step (3) heats the adhesive sheet (A) to form the adhesive sheet (B). 5. The method of manufacturing a semiconductor device according to claim 1, wherein said step of separating said plurality of attached chips from said adhesive sheet (A). 6. The method of manufacturing a semiconductor device according to claim 1, wherein the step (1) includes stretching the adhesive sheet (A) after dicing the workpiece. Any one of claims 1 to 6, wherein the adhesive layer (X1) of the adhesive sheet (A) has an adhesive strength of 0.1 to 10.0 N/25 mm at 23°C before the expandable particles expand. 2. A method for manufacturing a semiconductor device according to item 1. 8. The method of manufacturing a semiconductor device according to claim 1, wherein the surface of the base material (Y1) of the adhesive sheet (A) has a probe tack value of less than 50 mN/5 mmφ. The storage modulus E'(23) of the substrate (Y1) at 23°C is 5.0 × 10 ⁶ ～5.0×10 ¹² 9. The method of manufacturing a semiconductor device according to claim 1, wherein the material is Pa. 10. The method of manufacturing a semiconductor device according to claim 1, wherein said workpiece is a semiconductor wafer. 11. The method for manufacturing a semiconductor device according to claim 10, which is a method for manufacturing a fan-out type semiconductor device.

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