JP6980680B2 - Adhesive sheet for stealth dicing - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive sheet for stealth dicing (registered trademark), and preferably relates to a pressure-sensitive adhesive sheet for stealth dicing using a semiconductor wafer having a through electrode as a work.

In response to the increase in capacity and functionality of electronic circuits, the development of laminated circuits in which a plurality of semiconductor chips are three-dimensionally laminated is in progress. In such a laminated circuit, in the past, it was common to perform conductive connection of semiconductor chips by wire bonding, but due to the recent need for miniaturization and high functionality, semiconductors are not used without wire bonding. An effective method has been developed in which an electrode (TSV) penetrating from the circuit forming surface to the back surface is provided on the chip and the upper and lower chips are directly conductively connected to each other. As a method for manufacturing a chip with a through electrode, for example, a through hole is provided at a predetermined position on a semiconductor wafer by plasma or the like, a conductor such as copper is poured into the through hole, and then etching or the like is performed on the surface of the semiconductor wafer. A method of providing a circuit and a through electrode can be mentioned. At this time, the wafer will be heated.

Since such ultra-thin wafers and TSV wafers are extremely fragile, they may be damaged in the back grinding (back grind) process, the subsequent processing process, and the transfer process. Therefore, during these steps, the wafer is held on a hard support such as glass via an adhesive.

After the back surface grinding and processing of the wafer are completed, the wafer is transferred from the hard support onto the dicing sheet, the peripheral edge of the dicing sheet is fixed by a ring frame, and then the wafer is diced and individualized into multiple chips. After that, the chip is picked up from the dicing sheet.

When picking up the chip obtained by the above dicing, the dicing sheet to which the chip is attached is expanded. As a result, the chips are separated from each other, and it becomes easy to pick up the chips individually. In such an expand, the area of the dicing sheet to which the chip is attached is supported by the stage from the surface opposite to the surface to which the chip is attached, and is attached to the peripheral edge of the dicing sheet with respect to the height of the stage. This is done by relatively lowering the height of the ring frame.

Further, when performing the above expansion, after adsorbing the dicing sheet on the suction table while maintaining the expanded state, the area between the area where the ring frame is attached and the area where the chip is attached in the dicing sheet is formed. A process of heating and shrinking (heat shrink) may be performed. Due to the shrinkage, the dicing sheet generates a force to stretch the area to which the chips are attached toward the peripheral edge, and as a result, the chips are separated from each other even after the dicing sheet is released from the suction by the suction table. Can be maintained.

Patent Document 1 is provided with a predetermined base film and is subjected to a predetermined test, with one of the problems of exhibiting sufficient shrinkage in the heat shrinkage step and not causing a defect due to slack after the heat shrinkage step. A wafer processing tape having a maximum heat shrinkage stress of a predetermined value is disclosed.

Patent No. 5554118

By the way, as the dicing method, a dicing method using a dicing blade, a dicing method (stealth dicing) including forming a modified portion inside the wafer by irradiation with a laser beam and dividing by the modified portion, and the like are used. exist. Of these, in the method using the dicing blade, the portion of the wafer in contact with the dicing blade is cut, so that the obtained chips are separated by the cut width even when the dicing blade is not expanded. Become. On the other hand, in stealth dicing, a modified portion is formed in the wafer by irradiation with laser light, and the wafer is divided in the modified portion to obtain a plurality of chips. Therefore, the cut portion as described above does not occur in the wafer, and the obtained chips are almost in contact with each other in a state where the expansion is not performed.

Therefore, it is more difficult to maintain the chips widely separated from each other when performing the heat shrink described above in the case of performing stealth dicing than in the case of performing dicing using a dicing blade, resulting in poor pickup. Such problems are likely to occur. Therefore, in the adhesive sheet that is also used for stealth dicing, the adhesive sheet shrinks satisfactorily due to heat shrink, and the chips can be maintained in a satisfactorily separated state (hereinafter, may be referred to as "excellent in heat shrinkability"). Is especially required.

However, conventional adhesive sheets such as the wafer processing tape disclosed in Patent Document 1 do not have sufficient heat shrinkability, and it is difficult to maintain the chips widely separated from each other, especially when performing stealth dicing. As a result, problems such as poor pickup are likely to occur.

The present invention has been made in view of such an actual situation, and an object of the present invention is to provide an adhesive sheet for stealth dicing having excellent heat shrinkability.

In order to achieve the above object, first, the present invention is a pressure-sensitive adhesive sheet for stealth dicing including a base material and a pressure-sensitive adhesive layer laminated on one side of the base material, wherein the base material is: When the base material is pulled with a load of 0.2 g while heating from 25 ° C. to 120 ° C. at a heating rate of 20 ° C./min using a thermomechanical analyzer, the length of the base material at 60 ° C. The amount of change in the length of the base material obtained by subtracting the initial length of the base material is ΔL _{60 ° C.,} and the initial length of the base material is obtained from the length of the base material at 90 ° C. When the amount of change in the length of the base material obtained by subtracting is set to ΔL _{90 ° C.} , the following equation (1)
ΔL _{90 ° C − ΔL 60 ° C} <0 μm… (1)
(Invention 1), the present invention provides an adhesive sheet for stealth dicing, which is characterized by satisfying the above-mentioned relationship.

In the adhesive sheet for stealth dicing according to the above invention (Invention 1), the amount of change in the length of the base material ΔL _{90 ° C.} and ΔL _{60 °} C. measured by using a thermomechanical analyzer have the relationship of the above formula (1). By satisfying the conditions, excellent heat shrinkability can be exhibited, and as a result, the state in which the chips are separated from each other can be maintained satisfactorily, and as a result, problems such as poor pickup can be suppressed.

In the above invention (Invention 1), the base material is obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter in the DSC curve for the base material. When the minimum value of the measured value in the range of 30 ° C to 100 ° C is H _{30 ° C-100 ° C} and the measured value at _{25 ° C} is H 25 ° C, the following formula (2)
H _{30 ° C-100 ° C} / H _{25 ° C} ≤ 4.0 ... (2)
It is preferable to satisfy the above relationship (Invention 2).

In the above inventions (Inventions 1 and 2), the base material is a DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter. In the following equation (3), when the minimum value of the measured value in the range of 105 ° C to 200 ° C is H _{105 ° C-200 ° C} and the measured value at _{25 ° C is H 25 ° C.}
H _{105 ° C-200 ° C} / H _{25 ° C} ≧ 1.0… (3)
It is preferable to satisfy the above relationship (Invention 3).

In the above inventions (Inventions 1 to 3), the base material is a DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter. When the minimum value of the measured value in the range of 30 ° C to 100 ° C is H _{30 ° C-100 ° C} and the minimum value of the measured value in the range of 105 ° C to 200 ° C is H _{105 ° C-200 ° C} , the following Equation (4)
H _{105 ° C-200 ° C} / H _{30 ° C-100 ° C} ≧ 0.1… (4)
It is preferable to satisfy the above relationship (Invention 4).

In the above inventions (Inventions 1 to 4), the substrate preferably has a tensile elastic modulus of 50 MPa or more and 450 MPa or less at 23 ° C. (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable to use a semiconductor wafer having a through electrode as a work (Invention 6).

In the above inventions (Inventions 1 to 6), it is used in a method for manufacturing a semiconductor device including a step of shrinking a region where the work is not laminated by heating in the stealth dicing pressure-sensitive adhesive sheet on which the work is laminated. It is preferable (Invention 7).

The adhesive sheet for stealth dicing according to the present invention has excellent heat shrinkability.

Hereinafter, embodiments of the present invention will be described.
The pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment includes a base material and a pressure-sensitive adhesive layer laminated on one side of the base material.

1. 1. Components of Adhesive Sheet for Stealth Dicing (1) Base Material In the adhesive sheet for stealth dicing according to this embodiment, a thermomechanical analyzer is used to raise the base material from 25 ° C to 120 ° C at a heating rate of 20 ° C / min. When pulled with a load of 0.2 g while heating, the amount of change in the length of the base material obtained by subtracting the initial length of the base material from the length of the base material at _{60 ° C.} is ΔL 60 ° C. ( μm), and when the amount of change in the length of the base material obtained by subtracting the initial length of the base material from the length of the base material at _{90 ° C} is ΔL 90 ° C (μm), the base material becomes , The following formula (1)
ΔL _{90 ° C − ΔL 60 ° C} <0 μm… (1)
Satisfy the relationship.

When the base material satisfies the relationship of the above formula (1), it means that the length of the base material at 90 ° C. is shorter than the length at 60 ° C. Therefore, when the base material is heated to a temperature of, for example, 90 ° C. or higher and 200 ° C. or lower during heat shrink, the base material can be satisfactorily shrunk. As a result, the adhesive sheet for stealth dicing provided with the base material has excellent heat shrinkability, and after heat shrink, the chips can be well maintained in a separated state, and the chips collide with each other. It is possible to perform a suppressed and good pickup. The details of the measurement method of the change amounts ΔL _{90 ° C.} and ΔL _{60 ° C.} are as described in the test examples described later.

Further, from the viewpoint that the adhesive sheet for stealth dicing exhibits more excellent heat shrinkability, _{the value of ΔL 90 ° C.} −ΔL _{60 ° C.} is particularly preferably −10 μm or less. The lower limit of the value of ΔL _{90 ° C.} −ΔL _{60 ° C.} is not particularly limited, but is usually −3000 μm or more, and particularly preferably −2000 μm or more.

Examples of the work in which the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment is used include semiconductor wafers, semiconductor members such as semiconductor packages, and glass members such as glass plates. The semiconductor wafer may be a semiconductor wafer (TSV wafer) having a through electrode. As described above, the adhesive sheet for stealth dicing according to the present embodiment can suppress the collision between the chips after heat shrinking, so that the thickness is thin, and the work is liable to be damaged by the collision. Even when it is used, the damage can be effectively suppressed. Therefore, as a work in which an adhesive sheet for stealth dicing is used, a semiconductor wafer having a through electrode having a very thin thickness is generally suitable.

In the adhesive sheet for stealth dicing according to the present embodiment, the DSC curve for the substrate obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter shows a temperature of 30 ° C. When the minimum value of the measured value (mW) in the range of 100 ° C. is H _{30 ° C.-100 ° C.} and the measured value (mW) at _{25 ° C.} is H 25 ° C., the base material is the following formula (2). )
H _{30 ° C-100 ° C} / H _{25 ° C} ≤ 4.0 ... (2)
It is preferable to satisfy the relationship of. When the base material satisfies the above formula (2), the base material tends not to have an endothermic peak in the temperature range of 30 ° C. to 100 ° C., and the melting point of the base material becomes relatively high. Therefore, the base material and the adhesive sheet for stealth dicing provided with the base material have excellent heat resistance. In particular, even when the adhesive sheet for stealth dicing is placed on a heated adsorption table, adhesion to the adsorption table due to softening of the base material is suppressed, and the adhesive sheet for stealth dicing can be satisfactorily removed from the adsorption table. Can be separated. The details of the measurement method using the differential scanning calorimeter are as described in the test examples described later.

From the viewpoint that the adhesive sheet for stealth dicing exhibits further excellent heat resistance, _{the value of H 30 ° C-100 ° C} / H _{25 ° C} is particularly preferably 3.0 or less. The lower limit of the value of H _{30 ° C.-100 ° C./H 25 ° C.} is not particularly limited, but is usually preferably 0.1 or more.

In the adhesive sheet for stealth dicing according to the present embodiment, the DSC curve for the substrate obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter shows 105 ° C. When the minimum value of the measured value (mW) in the range from 200 ° C. is H _{105 ° C.-200 ° C.} and the measured value (mW) at _{25 ° C.} is H 25 ° C., the base material is the following formula (3). )
H _{105 ° C-200 ° C} / H _{25 ° C} ≧ 1.0… (3)
It is preferable to satisfy the relationship of. When the base material satisfies the above formula (3), the base material easily satisfies the relationship of the above-mentioned formula (1), and the adhesive sheet for stealth dicing provided with the base material effectively exhibits excellent heat shrinkability. It will be demonstrated. As a result, after heat shrinking, the state in which the chips are separated from each other can be better maintained, and good pickup in which the collision between the chips is suppressed can be effectively performed. The details of the measurement method using the differential scanning calorimeter are as described in the test examples described later.

From the viewpoint that the adhesive sheet for stealth dicing exhibits further excellent heat resistance, _{the value of H 105 ° C. −200 ° C./H 25 ° C.} is particularly preferably 1.1 or more. The upper limit of the value of H _{105 ° C-200 ° C} / H _{25 ° C} is not particularly limited, but is usually preferably 20 or less.

In the adhesive sheet for stealth dicing according to the present embodiment, the DSC curve for the substrate obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter shows a temperature of 30 ° C. When the minimum value of the measured value (mW) in the range of 100 ° C to 100 ° C is H _{30 ° C-100 ° C} and the minimum value of the measured value (mW) in the range of 105 ° C to 200 ° C is H _{105 ° C-200 ° C.} , The base material is the following formula (4)
H _{105 ° C-200 ° C} / H _{30 ° C-100 ° C} ≧ 0.1… (4)
It is preferable to satisfy the relationship of. When the base material satisfies the above formula (4), the base material easily satisfies the relationship of the above-mentioned formula (1), and the adhesive sheet for stealth dicing provided with the base material effectively exhibits excellent heat shrinkability. It will be demonstrated. As a result, after heat shrinking, the state in which the chips are separated from each other can be better maintained, and good pickup in which the collision between the chips is suppressed can be effectively performed. Further, when the base material satisfies the above formula (4), the base material tends not to have an endothermic peak in the temperature range of 30 ° C to 100 ° C, and has an endothermic peak in the temperature range of 105 ° C to 200 ° C. The tendency increases, and the melting point of the base material becomes relatively high. As a result, the base material and the adhesive sheet for stealth dicing provided with the base material have excellent heat resistance. In particular, even when the adhesive sheet for stealth dicing is placed on a heated adsorption table, adhesion to the adsorption table due to softening of the base material is suppressed, and the adhesive sheet for stealth dicing can be satisfactorily removed from the adsorption table. Can be separated. The details of the measurement method using the differential scanning calorimeter are as described in the test examples described later.

From the viewpoint that the adhesive sheet for stealth dicing exhibits further excellent heat resistance, _{the value of H 105 ° C-200 ° C} / H _{30 ° C-100 ° C} is particularly preferably 0.7 or more, and further 1 It is preferably .5 or more. The upper limit of the value of H _{105 ° C-200 ° C} / H _{30 ° C-100 ° C} is not particularly limited, but is usually preferably 20 or less.

In the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the tensile elastic modulus of the base material at 23 ° C. is preferably 450 MPa or less, particularly preferably 400 MPa or less, and further preferably 300 MPa or less. Further, the tensile elastic modulus is preferably 50 MPa or more, particularly preferably 70 MPa or more, and further preferably 100 MPa or more. When the tensile elastic modulus is 450 MPa or less, the base material easily shrinks due to heating, and therefore, after heat shrinking, it is possible to effectively maintain the semiconductor chips and the glass chips in a separated state. Become. On the other hand, when the tensile elastic modulus is 50 MPa or more, the base material has sufficient rigidity, and the stealth dicing pressure-sensitive adhesive sheet provided with the base material is excellent in processability and handleability. The details of the method for measuring the tensile elastic modulus are as described in the test examples described later.

The material of the base material is not particularly limited as long as it satisfies the relationship of the above formula (1) regarding the measurement by the thermomechanical analyzer and exhibits a desired function in the process of using the adhesive sheet for stealth dicing. Further, when the pressure-sensitive adhesive layer is composed of an energy ray-curable pressure-sensitive adhesive, the material of the base material may exhibit good permeability to the energy rays irradiated for curing the pressure-sensitive adhesive layer. preferable.

The base material is preferably a resin film whose main material is a resin-based material, and specific examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, and an ethylene-norbornene copolymer. Polyethylene-based films such as films and norbornene resin films; ethylene- (meth) acrylic acid copolymer films, ethylene- (meth) methyl acrylate copolymer films, and other ethylene- (meth) acrylic acid ester copolymer films. Ethylene-based copolymer films such as; ethylene-vinyl acetate copolymer films; polyvinyl chloride films, polyvinyl chloride-based films such as vinyl chloride copolymer films; (meth) acrylic acid ester copolymer films; polyurethane films; Polyvinyl film; fluororesin film; polyimide film; polycarbonate film and the like can be mentioned. In the polyolefin-based film, the polyolefin may be a block copolymer or a random copolymer. Examples of polyethylene films include low density polyethylene (LDPE) films, linear low density polyethylene (LLDPE) films, high density polyethylene (HDPE) films and the like. Further, modified films such as these crosslinked films and ionomer films are also used. Further, the base material may be a laminated film in which a plurality of the above-mentioned films are laminated. In this laminated film, the materials constituting each layer may be the same type or different types. In addition, "(meth) acrylic acid" in this specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the base material, among the above films, a low density polyethylene film, a linear low density polyethylene film, and a random copolymer polypropylene film (random) from the viewpoint of easily satisfying the relationship of the above formula (1) regarding the measurement by the thermomechanical analyzer. Polyethylene film) or polyethylene-methacrylic acid copolymer film is preferably used.

The substrate may contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ion scavengers and the like. The content of these additives is not particularly limited, but is preferably in the range in which the base material exhibits a desired function.

The surface on which the pressure-sensitive adhesive layer of the base material is laminated may be subjected to surface treatment such as primer treatment, corona treatment, and plasma treatment in order to improve the adhesion to the pressure-sensitive adhesive layer.

The thickness of the base material is preferably 450 μm or less, particularly preferably 400 μm or less, and further preferably 350 μm or less. The thickness is preferably 20 μm or more, particularly preferably 25 μm or more, and further preferably 50 μm or more. When the thickness of the base material is 450 μm or less, the base material is easily heat-shrinked, and the semiconductor chips and the glass chips can be kept satisfactorily separated from each other. Further, when the thickness of the base material is 20 μm or more, the base material has good rigidity, and the adhesive sheet for stealth dicing can effectively support the work.

(2) Adhesive layer In the pressure-sensitive adhesive sheet for stealth dicing according to the present embodiment, the pressure-sensitive adhesive layer is not particularly limited as long as it exhibits a desired function in the process of using the pressure-sensitive adhesive sheet for stealth dicing. When the pressure-sensitive adhesive sheet for stealth dicing is provided with the pressure-sensitive adhesive layer, it becomes easy to satisfactorily attach the work to the surface on the pressure-sensitive adhesive layer side.

The pressure-sensitive adhesive layer may be composed of a non-energy ray-curable pressure-sensitive adhesive or an energy ray-curable pressure-sensitive adhesive. The non-energy ray-curable pressure-sensitive adhesive preferably has desired adhesive strength and re-peelability, and is, for example, an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, or a polyester-based pressure-sensitive adhesive. , Polyvinyl ether adhesives and the like can be used. Among these, an acrylic pressure-sensitive adhesive that can effectively suppress the falling off of semiconductor chips and the like when the pressure-sensitive adhesive sheet for stealth dicing is stretched is preferable.

On the other hand, the energy ray-curable adhesive is cured by energy ray irradiation and the adhesive strength is lowered. Therefore, when it is desired to separate the semiconductor chip and the adhesive sheet for stealth dicing, the energy ray-curable adhesive can be easily separated by irradiating with energy rays. Can be made to.

The energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be mainly composed of a polymer having energy ray-curing property, or a non-energy ray-curable polymer (polymer having no energy ray-curing property). It may be mainly composed of a mixture of a monomer having at least one energy ray-curable group and / or an oligomer. It may also be a mixture of an energy ray curable polymer and a non-energy ray curable polymer, a monomer having an energy ray curable polymer and at least one energy ray curable group, and / or. It may be a mixture with an oligomer or a mixture of three kinds thereof.

First, a case where the energy ray-curable pressure-sensitive adhesive contains a polymer having energy ray-curability as a main component will be described below.

The polymer having energy ray curability is a (meth) acrylic acid ester (co) polymer (A) in which a functional group (energy ray curable group) having energy ray curability is introduced into the side chain (hereinafter referred to as “energy ray curable”). It may be referred to as "curable polymer (A)"). This energy ray-curable polymer (A) reacts an acrylic copolymer (a1) having a functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group. It is preferable that it is obtained by allowing it to be obtained.

The acrylic copolymer (a1) preferably contains a structural unit derived from a functional group-containing monomer and a structural unit derived from a (meth) acrylic acid ester monomer or a derivative thereof.

The functional group-containing monomer as a constituent unit of the acrylic copolymer (a1) has a polymerizable double bond and a functional group such as a hydroxy group, a carboxy group, an amino group, a substituted amino group and an epoxy group in the molecule. It is preferable that the monomer is contained in.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl ( Examples thereof include meth) acrylate and 4-hydroxybutyl (meth) acrylate, which are used alone or in combination of two or more.

Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer or the substituted amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

As the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1), in addition to the alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, for example, an alicyclic structure in the molecule is formed. A monomer having an alicyclic structure (monomer containing an alicyclic structure) is preferably used.

Examples of the alkyl (meth) acrylate include alkyl (meth) acrylates having an alkyl group having 1 to 18 carbon atoms, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (. Meta) acrylate, 2-ethylhexyl (meth) acrylate and the like are preferably used. These may be used individually by 1 type, or may be used in combination of 2 or more type.

Examples of the alicyclic structure-containing monomer include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate, isobornyl (meth) acrylate, and dicyclopentenyl (meth) acrylate. , (Meta) dicyclopentenyloxyethyl acrylate and the like are preferably used. These may be used individually by 1 type, or may be used in combination of 2 or more type.

The acrylic copolymer (a1) contains a structural unit derived from the functional group-containing monomer in an amount of preferably 1% by mass or more, particularly preferably 5% by mass or more, still more preferably 10% by mass or more. Further, the acrylic copolymer (a1) contains a structural unit derived from the functional group-containing monomer in a proportion of preferably 35% by mass or less, particularly preferably 30% by mass or less, still more preferably 25% by mass or less. do.

Further, the acrylic copolymer (a1) contains a structural unit derived from the (meth) acrylic acid ester monomer or a derivative thereof, preferably 50% by mass or more, particularly preferably 60% by mass or more, still more preferably 70% by mass. It is contained in the above ratio. Further, the acrylic copolymer (a1) contains a structural unit derived from the (meth) acrylic acid ester monomer or a derivative thereof, preferably 99% by mass or less, particularly preferably 95% by mass or less, still more preferably 90% by mass. It is contained in the following proportions.

The acrylic copolymer (a1) can be obtained by copolymerizing a functional group-containing monomer as described above with a (meth) acrylic acid ester monomer or a derivative thereof by a conventional method, but in addition to these monomers, Dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like may be copolymerized.

An energy ray-curable polymer (A) is obtained by reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with the unsaturated group-containing compound (a2) having a functional group bonded to the functional group. ) Is obtained.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected depending on the type of the functional group of the functional group-containing monomer unit of the acrylic copolymer (a1). For example, when the functional group of the acrylic copolymer (a1) is a hydroxy group, an amino group or a substituted amino group, the functional group of the unsaturated group-containing compound (a2) is preferably an isocyanate group or an epoxy group, and acrylic. When the functional group of the system copolymer (a1) is an epoxy group, the functional group of the unsaturated group-containing compound (a2) is preferably an amino group, a carboxy group or an aziridinyl group.

Further, the unsaturated group-containing compound (a2) contains at least one, preferably 1 to 6, and more preferably 1 to 4 energy ray-polymerizable carbon-carbon double bonds in one molecule. ing. Specific examples of such an unsaturated group-containing compound (a2) include 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, and 1,1-(. Bisacrylloyloxymethyl) ethyl isocyanate; Acryloyl monoisocyanate compound obtained by reacting a diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; a diisocyanate compound or polyisocyanate compound, a polyol compound, and hydroxyethyl (meth). Acryloyl monoisocyanate compound obtained by reaction with acrylate; glycidyl (meth) acrylate; (meth) acrylic acid, 2- (1-aziridinyl) ethyl (meth) acrylate, 2-vinyl-2-oxazoline, 2-isopropenyl- 2-Oxazoline and the like can be mentioned.

The unsaturated group-containing compound (a2) is preferably 50 mol% or more, particularly preferably 60 mol% or more, still more preferably 70 mol, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). Used at a rate of% or more. The unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, still more preferably 93 mol% or less, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used in a proportion of 90 mol% or less.

In the reaction between the acrylic copolymer (a1) and the unsaturated group-containing compound (a2), the functional group of the acrylic copolymer (a1) and the functional group of the unsaturated group-containing compound (a2) are used. Depending on the combination, the reaction temperature, pressure, solvent, time, presence / absence of catalyst, and type of polymer can be appropriately selected. As a result, the functional group present in the acrylic copolymer (a1) reacts with the functional group in the unsaturated group-containing compound (a2), and the unsaturated group is contained in the acrylic copolymer (a1). It is introduced into the side chain to obtain an energy ray-curable polymer (A).

The weight average molecular weight (Mw) of the energy ray-curable polymer (A) thus obtained is preferably 10,000 or more, particularly preferably 150,000 or more, and further preferably 200,000 or more. Is preferable. The weight average molecular weight (Mw) is preferably 1.5 million or less, and particularly preferably 1 million or less. The weight average molecular weight (Mw) in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography method (GPC method).

Even when the energy ray-curable pressure-sensitive adhesive contains a polymer having energy ray-curable properties such as the energy ray-curable polymer (A) as a main component, the energy ray-curable pressure-sensitive adhesive is an energy ray-curable monomer. And / or the oligomer (B) may be further contained.

As the energy ray-curable monomer and / or oligomer (B), for example, an ester of a polyhydric alcohol and (meth) acrylic acid can be used.

Examples of the energy ray-curable monomer and / or oligomer (B) include monofunctional acrylic acid esters such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate, trimethyl propanthry (meth) acrylate, and penta. Elythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol Examples thereof include polyfunctional acrylic acid esters such as di (meth) acrylate and dimethylol tricyclodecanedi (meth) acrylate, polyester oligo (meth) acrylate, and polyurethane oligo (meth) acrylate.

When the energy ray-curable monomer and / or oligomer (B) is blended with the energy ray-curable polymer (A), the energy ray-curable monomer and / or oligomer (B) in the energy ray-curable pressure-sensitive adhesive. ) Is preferably more than 0 parts by mass, and particularly preferably 60 parts by mass or more, with respect to 100 parts by mass of the energy ray-curable polymer (A). The content is preferably 250 parts by mass or less, and particularly preferably 200 parts by mass or less, with respect to 100 parts by mass of the energy ray-curable polymer (A).

Here, when ultraviolet rays are used as energy rays for curing the energy ray-curable pressure-sensitive adhesive, it is preferable to add a photopolymerization initiator (C), and by using this photopolymerization initiator (C), The polymerization curing time and the amount of light irradiation can be reduced.

Specific examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, and benzoin dimethyl ketal. 2,4-diethylthioxanthone, 1-hydroxycyclohexylphenylketone, benzyldiphenylsulfide, tetramethylthium monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4) 6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-methyl-1- [4- (1-propenyl) phenyl] propanone}, 2, Examples thereof include 2-dimethoxy-1,2-diphenylethane-1-one. These may be used alone or in combination of two or more.

The photopolymerization initiator (C) is an energy ray-curable copolymer (A) (in the case of blending an energy ray-curable monomer and / or an oligomer (B), the energy ray-curable copolymer (A)). And the total amount of the energy ray-curable monomer and / or oligomer (B) is 100 parts by mass) 0.1 parts by mass or more, particularly preferably 0.5 parts by mass or more with respect to 100 parts by mass. Further, the photopolymerization initiator (C) is an energy ray-curable copolymer (A) (when the energy ray-curable monomer and / or oligomer (B) is blended, the energy ray-curable copolymer (A). The total amount of A) and the energy ray-curable monomer and / or oligomer (B) is 100 parts by mass). It is preferably used in an amount of 10 parts by mass or less, particularly 6 parts by mass or less with respect to 100 parts by mass.

In the energy ray-curable pressure-sensitive adhesive, other components may be appropriately added in addition to the above components. Examples of other components include a non-energy ray-curable polymer component or an oligomer component (D), a cross-linking agent (E), and the like.

Examples of the non-energy ray-curable polymer component or oligomer component (D) include polyacrylic acid esters, polyesters, polyurethanes, polycarbonates, polyolefins and the like, and polymers or oligomers having a weight average molecular weight (Mw) of 3000 to 2.5 million. Is preferable. By blending the component (D) with an energy ray-curable pressure-sensitive adhesive, it is possible to improve the adhesiveness and peelability before curing, the strength after curing, the adhesiveness with other layers, the storage stability and the like. The blending amount of the component (D) is not particularly limited, and is appropriately determined in the range of more than 0 parts by mass and 50 parts by mass or less with respect to 100 parts by mass of the energy ray-curable copolymer (A).

As the cross-linking agent (E), a polyfunctional compound having reactivity with a functional group of the energy ray-curable copolymer (A) or the like can be used. Examples of such polyfunctional compounds include isocyanate compounds, epoxy compounds, amine compounds, melamine compounds, aziridine compounds, hydrazine compounds, aldehyde compounds, oxazoline compounds, metal alkoxide compounds, metal chelate compounds, metal salts, ammonium salts, etc. Examples thereof include reactive phenolic resins.

The blending amount of the cross-linking agent (E) is preferably 0.01 part by mass or more, particularly 0.03 part by mass or more, with respect to 100 parts by mass of the energy ray-curable copolymer (A). It is preferable, more preferably 0.04 parts by mass or more. The amount of the cross-linking agent (E) to be blended is preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, based on 100 parts by mass of the energy ray-curable copolymer (A). Further, it is preferably 3.5 parts by mass or less.

Next, a case where the energy ray-curable pressure-sensitive adhesive contains a mixture of a non-energy ray-curable polymer component and a monomer and / or an oligomer having at least one energy ray-curable group as a main component will be described below. ..

As the non-energy ray-curable polymer component, for example, the same component as the above-mentioned acrylic copolymer (a1) can be used.

As the monomer and / or oligomer having at least one energy ray-curable group, the same one as the above-mentioned component (B) can be selected. The compounding ratio of the non-energy ray-curable polymer component to the monomer and / or oligomer having at least one energy ray-curable group is at least one or more with respect to 100 parts by mass of the non-energy ray-curable polymer component. The amount is preferably 1 part by mass or more of the monomer and / or oligomer having an energy ray-curable group, and particularly preferably 60 parts by mass or more. The compounding ratio is preferably 200 parts by mass or less of the monomer and / or oligomer having at least one energy ray-curable group with respect to 100 parts by mass of the non-energy ray-curable polymer component. It is preferably less than or equal to parts by mass.

Also in this case, the photopolymerization initiator (C) and the cross-linking agent (E) can be appropriately blended in the same manner as described above.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, particularly preferably 2 μm or more, and further preferably 3 μm or more. The thickness is preferably 50 μm or less, particularly preferably 30 μm or less, and further preferably 20 μm or less. When the thickness of the pressure-sensitive adhesive layer is 1 μm or more, good adhesive strength is exhibited for the work of the pressure-sensitive adhesive sheet for stealth dicing, and peeling of the work at an unintended stage can be effectively suppressed. .. Further, when the thickness of the pressure-sensitive adhesive layer is 50 μm or less, it is possible to prevent the adhesive strength of the pressure-sensitive adhesive sheet for stealth dicing from becoming excessively high, and it is possible to effectively suppress the occurrence of pick-up defects and the like.

(3) Release sheet In the adhesive sheet for stealth dicing according to the present embodiment, the release sheet is laminated on the surface for the purpose of protecting the adhesive surface until the adhesive surface of the adhesive layer is attached to the work. May be good. The structure of the release sheet is arbitrary, and examples thereof include a plastic film peeled with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, a silicone type, a fluorine type, a long chain alkyl type or the like can be used, and among these, a silicone type which can obtain stable performance at a low cost is preferable. The thickness of the release sheet is not particularly limited, but is usually 20 μm or more and 250 μm or less.

2. 2. Method for Manufacturing Adhesive Sheet for Stealth Dicing In the adhesive sheet for stealth dicing according to the present embodiment, the method for producing the base material is as long as the obtained base material satisfies the relationship of the above formula (1) regarding the measurement by the thermomechanical analyzer. Not particularly limited. For example, using the above-mentioned materials, a base material can be produced by a melt extrusion method such as a T-die method or a round die method; a calendar method; a solution method such as a dry method or a wet method. Among these manufacturing methods, it is preferable to use the T-die method.

Further, in the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, the method for forming the pressure-sensitive adhesive layer is not particularly limited. For example, a stealth dicing pressure-sensitive adhesive sheet can be obtained by transferring the pressure-sensitive adhesive layer formed on the release sheet to one side of the base material produced as described above. In this case, a pressure-sensitive composition constituting the pressure-sensitive adhesive layer and, if desired, a coating liquid containing a solvent or a dispersion medium may be prepared and the peel-treated surface of the peel-off sheet (hereinafter referred to as "peeling surface"). A coating liquid is applied onto the coating liquid using a die coater, a curtain coater, a spray coater, a slit coater, a knife coater, etc. to form a coating film, and the coating film is dried to form an adhesive layer. be able to. The properties of the coating liquid are not particularly limited as long as it can be applied, and the coating liquid may contain a component for forming the pressure-sensitive adhesive layer as a solute or as a dispersoid. The release sheet in this laminate may be peeled off as a process material, or may be used to protect the adhesive surface of the adhesive layer until the adhesive sheet for stealth dicing is attached to the work.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a cross-linking agent, the inside of the coating film may be changed by changing the above-mentioned drying conditions (temperature, time, etc.) or by separately providing a heat treatment. The cross-linking reaction between the energy ray-curable polymer (A) or the non-energy ray-curable polymer component and the cross-linking agent (E) may be allowed to proceed to form a cross-linked structure in the pressure-sensitive adhesive layer at a desired abundance density. In order to sufficiently proceed this cross-linking reaction, after laminating the pressure-sensitive adhesive layer on the substrate by the above method or the like, the obtained pressure-sensitive adhesive sheet for stealth dicing is placed in an environment of, for example, 23 ° C. and a relative humidity of 50%. It may be cured by letting it stand for a day.

Instead of transferring the pressure-sensitive adhesive layer formed on the release sheet to one side of the base material as described above, the pressure-sensitive adhesive layer may be formed directly on the base material. In this case, the above-mentioned coating liquid for forming the pressure-sensitive adhesive layer is applied to one side of the base material to form a coating film, and the coating film is dried to form the pressure-sensitive adhesive layer.

3. 3. Method of Using Adhesive Sheet for Stealth Dicing The adhesive sheet for stealth dicing according to the present embodiment can be used for stealth dicing. Further, the adhesive sheet for stealth dicing according to the present embodiment can be used in a method for manufacturing a semiconductor device including a stealth dicing step.

As described above, the adhesive sheet for stealth dicing according to the present embodiment can suppress the collision between the chips after heat shrinking, and is therefore suitable for a work having a thin thickness and which is likely to cause damage to the chips. can do. For example, the adhesive sheet for stealth dicing according to the present embodiment can be suitably used for a semiconductor wafer (TSV) having a through electrode.

Hereinafter, an example of a method for manufacturing a semiconductor device including a stealth dicing process will be described. First, a step of grinding (back grinding) one side of a work (semiconductor wafer) fixed to a hard support is performed. The semiconductor wafer is fixed to the hard support with, for example, an adhesive. As the hard support, for example, glass or the like is used. Backgrinding can be done by a general method.

Subsequently, the semiconductor wafer whose back grind is completed is transferred from the rigid support to the adhesive sheet for stealth dicing. At this time, the surface of the pressure-sensitive adhesive sheet for stealth dicing on the pressure-sensitive adhesive layer side is attached to the back-grinded surface of the semiconductor wafer, and then the hard support is separated from the semiconductor wafer. Separation of the hard support from the semiconductor wafer can be performed by a method according to the type of adhesive used for fixing the hard support and the semiconductor wafer. For example, after softening the adhesive by heating, the adhesive can be separated. , A method of sliding a hard support from a semiconductor wafer, a method of decomposing an adhesive by irradiation with laser light, and the like. After the hard support is separated from the semiconductor wafer, the peripheral portion of the adhesive sheet for stealth dicing is attached to the ring frame.

Subsequently, a step of cleaning the semiconductor wafer laminated on the stealth dicing pressure-sensitive adhesive sheet with a solvent is performed. This makes it possible to remove the adhesive remaining on the semiconductor wafer. The cleaning can be performed by a general method, for example, a method of immersing a laminate of a stealth dicing pressure-sensitive adhesive sheet and a semiconductor wafer in a solvent, and surrounding the wafer with a frame slightly larger than the semiconductor wafer. A method of arranging the adhesive sheet for stealth dicing and pouring a solvent into the frame can be mentioned.

Subsequently, if necessary, another semiconductor wafer may be laminated on the semiconductor wafer laminated on the stealth dicing pressure-sensitive adhesive sheet. At this time, the semiconductors can be fixed to each other by using an adhesive or the like, and can be fixed by, for example, a nonconductive film (NCF). The stacking of semiconductor wafers may be repeated until the required number of stacks is reached. Such lamination of semiconductor wafers is particularly preferably performed when a TSV wafer is used as the semiconductor wafer and a laminated circuit is manufactured.

Subsequently, stealth of a semiconductor wafer or a laminate of semiconductor wafers on an adhesive sheet for stealth dicing (hereinafter, "semiconductor wafer" means a semiconductor wafer or a laminate of semiconductor wafers unless otherwise specified). Dicing is done. In this step, the semiconductor wafer is irradiated with laser light to form a modified portion in the semiconductor wafer. The irradiation of the laser beam can be performed using the devices and conditions generally used in stealth dicing.

Subsequently, the semiconductor wafer is divided in a reforming portion formed by stealth dicing to obtain a plurality of semiconductor chips. The division can be performed, for example, by installing a laminate of a stealth dicing pressure-sensitive adhesive sheet and a semiconductor wafer in an expanding device and expanding it in an environment of 0 ° C. to room temperature.

Then, the adhesive sheet for stealth dicing is expanded again. The expansion is performed mainly for the purpose of separating the obtained semiconductor chips from each other. Further, the adhesive sheet for stealth dicing is adsorbed on the adsorption table while maintaining the expanded state. The expansion here can be performed at room temperature or in a heated state. Further, the expansion can be performed by a general method using a general device, and the suction table used can also be performed by a general method.

Subsequently, while the stealth dicing pressure-sensitive adhesive sheet is adsorbed on the adsorption table, the region of the stealth dicing pressure-sensitive adhesive sheet on which the obtained semiconductor chips are laminated is shrunk (heat-shrinked) by heating. .. Specifically, the region between the region where the semiconductor chips are laminated in the stealth dicing pressure-sensitive adhesive sheet and the region where the ring frame is attached in the stealth dicing pressure-sensitive adhesive sheet is heated to shrink the region. As the heating conditions at this time, it is preferable that the temperature of the pressure-sensitive adhesive sheet for stealth dicing is 90 ° C. or higher. Further, the temperature of the adhesive sheet for stealth dicing is preferably 200 ° C. or lower. In the adhesive sheet for stealth dicing according to the present embodiment, the amount of change in the length of the base material ΔL _{90 ° C.} and ΔL _{60 °} C. measured by using a thermomechanical analyzer satisfies the relationship of the above-mentioned formula (1). , The base material can be satisfactorily shrunk by heating. As a result, as will be described later, even after the adhesive sheet for stealth dicing is released from the adsorption by the adsorption table, the state in which the semiconductor chips are separated from each other can be maintained well, and the semiconductor chips can be picked up satisfactorily. Can be done.

Subsequently, the adhesive sheet for stealth dicing is released from the adsorption by the adsorption table described above. In the heat shrink step, the region between the region where the semiconductor chips are laminated in the adhesive sheet for stealth dicing and the region where the ring frame is attached in the adhesive sheet for stealth dicing shrinks, so that the adhesive sheet for stealth dicing shrinks. Then, a force is generated to stretch the region to which the semiconductor chip is attached toward the peripheral edge portion. As a result, the semiconductor chips can be maintained in a separated state even after being released from the suction by the suction table.

Then, the individual semiconductor chips are picked up from the adhesive sheet for stealth dicing in a state of being separated from the adjacent semiconductor chips. This pickup can be done in a general way using common equipment. As described above, the adhesive sheet for stealth dicing according to the present embodiment exhibits excellent heat shrinkability, and as a result, the semiconductor chips can be maintained in a state of being well separated from each other, thereby making the pickup good. It can be carried out.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, another layer may be provided between the base material and the pressure-sensitive adhesive layer, or on the surface of the base material opposite to the pressure-sensitive adhesive layer.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
(1) Preparation of base material A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "Sumicasen F-421-1") is used in a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "". It was extruded by "Laboplast Mill") to obtain a substrate having a thickness of 70 μm.

(2) Preparation of pressure-sensitive adhesive composition 62 parts by mass of n-butyl (BA) acrylate, 10 parts by mass of methyl methacrylate (MMA) and 28 parts by mass of 2-hydroxyethyl acrylate (HEA) are reacted. The obtained acrylic copolymer (a1) is reacted with 80 mol% of methacryloyloxyethyl isocyanate (MOI) with respect to the HEA of the acrylic copolymer (a1) to form an energy ray-curable polymer (MOI). A) was obtained. When the molecular weight of this energy ray-curable polymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 500,000.

100 parts by mass of the obtained energy ray-curable polymer (solid content equivalent, the same applies hereinafter) and 3.0 mass of 1-hydroxycyclohexylphenylketone (manufactured by BASF, product name "Irgacure 184") as a photopolymerization initiator. A portion and 1.0 part by mass of tolylene diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") as a cross-linking agent were mixed in a solvent to obtain a pressure-sensitive adhesive composition.

(3) Formation of Adhesive Layer The peeling surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET38131") in which a silicone-based release agent layer is formed on one side of a polyethylene terephthalate (PET) film having a thickness of 38 μm. On the other hand, the pressure-sensitive adhesive composition was applied and dried by heating to form a pressure-sensitive adhesive layer having a thickness of 20 μm on the release sheet.

(4) Preparation of adhesive sheet for stealth dicing By bonding the surface of the adhesive layer formed in the above step (3) opposite to the release sheet and one side of the base material prepared in the above step (1). , Obtained an adhesive sheet for stealth dicing.

[Example 2]
A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "Sumikasen F-723P") is used as a base material, and a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill") is used. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a base material having a thickness of 70 μm obtained by extrusion molding was used.

[Example 3]
A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name "Sumikasen CE3506") is extruded by a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill") as a base material. A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a 70 μm-thick substrate obtained by molding was used.

[Example 4]
A resin composition containing random polypropylene as a base material (manufactured by Prime Polymer Co., Ltd., product name "Prime TPO J-5710") is used in a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill"). A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a base material having a thickness of 70 μm obtained by extrusion molding was used.

[Example 5]
A resin composition containing random polypropylene as a base material (manufactured by Prime Polymer Co., Ltd., product name "Prime TPO F-3740") is used in a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Laboplast Mill"). A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a base material having a thickness of 70 μm obtained by extrusion molding was used.

[Example 6]
As a base material, a resin composition containing an ethylene-methacrylic acid copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd., product name "Nucrel NH903C") is used in a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Lab"). A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a base material having a thickness of 70 μm obtained by extrusion molding with a plast mill ”) was used.

[Comparative Example 1]
A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a polybutylene terephthalate film having a thickness of 80 μm was used as a base material.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard volume HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C

[Test Example 1] (Measurement of tensile modulus of substrate)
The substrates prepared in Examples and Comparative Examples were cut into 15 mm × 140 mm test pieces, and the tensile modulus was measured at a temperature of 23 ° C. and a relative humidity of 50% according to JIS K7161: 2014. Specifically, the above test piece is set to a chuck distance of 100 mm with a tensile tester (manufactured by Orientec, product name "Tensilon RTA-T-2M"), and then a tensile test is performed at a speed of 200 mm / min. The tensile elastic modulus (MPa) was measured. The measurement was performed in both the extrusion direction (MD) at the time of molding the base material and the direction perpendicular to the extrusion direction (CD), and the average value of these measurement results was taken as the tensile modulus fracture elongation. The results are shown in Table 1.

[Test Example 2] (Measurement by differential scanning calorimeter)
4.0 mg of the substrate prepared in Examples and Comparative Examples was cut out and used as a measurement sample. The measurement sample was heated from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter (manufactured by TA Instruments, product name “Q2000”) to obtain a DSC curve.

In the obtained DSC curve, the measured value (mW) at _{25 ° C. is H 25 ° C.,} and the minimum value of the measured value (mW) in the range of 30 ° C. to 100 ° C. is H _{30 ° C.-100 ° C.} , 105 ° C. The minimum value of the measured value (mW) in the range from 200 ° C to 200 ° C was set to H _{105 ° C-200 ° C.} These results are shown in Table 1.

Also, _{H 30 ℃ -100 ℃} ratio _{(H 30 ℃ -100 ℃ / H} 25 ℃) against _{H 25 ° C.,} the ratio of _{H 105 ° C. -200 ° C.} for _{H 25 ℃ (H 105 ℃ -200} ℃ / H 25 ℃ ), and the ratio of _{H 105 ° C. -200 ° C.} for _{H 30 ℃ -100 ℃ (H 105} ℃ -200 ℃ / H 30 ℃ -100 ℃) was calculated. These results are shown in Table 1.

[Test Example 3] (Measurement by thermomechanical analyzer)
The base materials prepared in Examples and Comparative Examples were cut into a size of 4.5 mm × 20 mm and used as a measurement sample. The measurement sample was installed in a thermomechanical analyzer (manufactured by BRUKER, product name "TMA4000SA") with a chuck-to-chuck distance of 15 mm, and then heated from 25 ° C to 120 ° C at a heating rate of 20 ° C / min. It was pulled in the long axis direction with a load of 0.2 g. Then, the distances between the chucks of the measurement samples at 60 ° C. and 90 ° C. were measured, respectively.

Then, by subtracting the initial chuck-to-chuck distance from the chuck-to-chuck distance of the measurement sample at _{60 ° C., the} amount of change in the chuck-to-chuck distance of the measurement sample ΔL 60 ° C. (μm) was calculated. Further, by subtracting the initial chuck-to-chuck distance from the chuck-to-chuck distance of the measurement sample at _{90 ° C., the} amount of change in the chuck-to-chuck distance of the measurement sample ΔL 90 ° C. (μm) was calculated. Further, a value (ΔL _{90 ° C. − ΔL 60 ° C.} ) (μm) obtained by subtracting ΔL _{60 ° C. from ΔL 90 ° C. was calculated.} These results are shown in Table 1.

[Test Example 4] (Evaluation of heat resistance)
After peeling the release sheet from the stealth dicing pressure-sensitive adhesive sheet manufactured in Examples and Comparative Examples, the surface of the stealth dicing pressure-sensitive adhesive sheet on the substrate side is surfaced with a multi-wafer mounter (manufactured by Lintec Corporation, product name "RAD-2700 F"). It was adsorbed on the adsorption table provided with / 12 ") for 2 minutes. During the adsorption, the adsorption table was heated to 70 ° C.

After 2 minutes had elapsed, the suction by the suction table was stopped, and then the transport means provided in the multi-wafer mounter was driven so that the adhesive sheet for stealth dicing was separated from the suction table. At this time, the one in which the separation was performed well and the adhesive sheet for stealth dicing could be conveyed without any problem was marked with "○", and the adhesive sheet for stealth dicing was slightly adhered to the porous table, but the adhesive sheet for stealth dicing was slightly adhered. The heat resistance of the stealth dicing adhesive sheet is evaluated as "△" for those that could be transported and "×" for those that could not be transported because the adhesive sheet for stealth dicing completely adhered to the porous table. did. The results are shown in Table 1.

The above evaluation of heat resistance was also performed when the suction table was heated to 90 ° C. The results are shown in Table 1.

[Test Example 5] (Evaluation of heat shrinkability)
The release sheet was peeled off from the adhesive sheet for stealth dicing manufactured in Examples and Comparative Examples, and the multi-wafer mounter (manufactured by Lintec Corporation, product name "RAD-2700 F / 12") was applied to the adhesive surface of the exposed adhesive layer. ) Was attached to a silicon wafer (outer diameter: 8 inches, thickness: 100 μm) and a ring frame (made of stainless steel).

Next, the silicon wafer attached on the adhesive sheet for stealth dicing is irradiated with a laser beam having a wavelength of 1342 nm using a laser saw (manufactured by DISCO, product name “DFL7361”), and the obtained chip size is 8 mm. A modified portion was formed in the silicon wafer so as to have a size of × 8 mm.

Next, the silicon wafer and ring frame after laser irradiation to which the adhesive sheet for stealth dicing was attached were installed on a die separator (manufactured by Disco Corporation, product name "DDS2300"), and the withdrawal speed was 100 mm / at 0 ° C. It was expanded (cool expanded) with an expanding amount of 10 mm per second. As a result, the semiconductor wafer was divided at the reforming portion, and a plurality of semiconductor chips having a chip size of 8 mm × 8 mm were obtained.

Subsequently, the adhesive sheet for stealth dicing was expanded at a withdrawal speed of 1 mm / sec and an expanding amount of 7 mm. Further, after adsorbing the stealth dicing pressure-sensitive adhesive sheet on the adsorption table in the expanded state, the area between the region where the semiconductor chip was attached and the region where the ring frame was attached was heated in the stealth dicing pressure-sensitive adhesive sheet. As the heating conditions at this time, the set temperature of the IR heater was set to 600 ° C., the rotation speed was set to 1 deg / sec, and the distance between the suction table supporting the adhesive sheet for stealth dicing and the heater was set to 13 mm. As a result, the adhesive sheet for stealth dicing was heated to about 180 ° C.

After that, the adhesive sheet for stealth dicing was released from the adsorption by the adsorption table, the distance between the adjacent semiconductor chips was measured at 5 points, and the average value was calculated. Then, the heat shrinkability was evaluated by setting the case where the average value is 20 μm or more as “◯” and the case where the average value is less than 20 μm as “x”. The results are shown in Table 1.

As can be seen from Table 1, the adhesive sheet for stealth dicing obtained in the examples was excellent in heat shrinkability. Further, the adhesive sheets for stealth dicing obtained in Examples 1 to 3 were also excellent in heat resistance.

The adhesive sheet for stealth dicing of the present invention can be suitably used when stealth dicing a semiconductor wafer having a through electrode.

Claims (7)

A stealth dicing pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer laminated on one side of the base material.
60 of the base material when the base material is pulled with a load of 0.2 g while heating from 25 ° C. to 120 ° C. at a heating rate of 20 ° C./min using a thermomechanical analyzer. The amount of change in the length of the base material obtained by subtracting the initial length of the base material from the length at _{° C. is ΔL 60 ° C.} , and the base material is obtained from the length of the base material at 90 ° C. When the amount of change in the length of the base material obtained by subtracting the initial length of is ΔL _{90 ° C.} , the following equation (1)
_{ΔL 90 ℃ -ΔL 60 ℃ <0μm} ... (1)
Satisfy the relationship,
The base material is in the range of 30 ° C. to 100 ° C. in the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter. When the minimum value of the measured value is H _{30 ° C-100 ° C} and the measured value at _{25 ° C} is H 25 ° C, the following formula (2)
H _{30 ° C-100 ° C} / H _{25 ° C} ≤ 4.0 ... (2)
Features and to Luz stealth dicing adhesive sheet that satisfies the relationship. A stealth dicing pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer laminated on one side of the base material.
60 of the base material when the base material is pulled with a load of 0.2 g while heating from 25 ° C. to 120 ° C. at a heating rate of 20 ° C./min using a thermomechanical analyzer. The amount of change in the length of the base material obtained by subtracting the initial length of the base material from the length at _{° C. is ΔL 60 ° C.} , and the base material is obtained from the length of the base material at 90 ° C. When the amount of change in the length of the base material obtained by subtracting the initial length of is ΔL _{90 ° C.} , the following equation (1)
_{ΔL 90 ℃ -ΔL 60 ℃ <0μm} ... (1)
Satisfy the relationship,
The base material is in the range of 105 ° C. to 200 ° C. in the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter. When the minimum value of the measured value is H _{105 ° C-200 ° C} and the measured value at _{25 ° C} is H 25 ° C, the following formula (3)
H _{105 ° C-200 ° C} / H _{25 ° C} ≧ 1.0… (3)
Features and to Luz stealth dicing adhesive sheet that satisfies the relationship. A stealth dicing pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer laminated on one side of the base material.
60 of the base material when the base material is pulled with a load of 0.2 g while heating from 25 ° C. to 120 ° C. at a heating rate of 20 ° C./min using a thermomechanical analyzer. The amount of change in the length of the base material obtained by subtracting the initial length of the base material from the length at _{° C. is ΔL 60 ° C.} , and the base material is obtained from the length of the base material at 90 ° C. When the amount of change in the length of the base material obtained by subtracting the initial length of is ΔL _{90 ° C.} , the following equation (1)
_{ΔL 90 ℃ -ΔL 60 ℃ <0μm} ... (1)
Satisfy the relationship,
The base material is in the range of 30 ° C. to 100 ° C. in the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter. When the minimum value of the measured value is H _{30 ° C-100 ° C} and the minimum value of the measured value in the range of 105 ° C to 200 ° C is H _{105 ° C-200 ° C} , the following formula (4)
H _{105 ° C-200 ° C} / H _{30 ° C-100 ° C} ≧ 0.1… (4)
Features and to Luz stealth dicing adhesive sheet that satisfies the relationship. The pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 3 , wherein the base material has a tensile elastic modulus of 50 MPa or more and 450 MPa or less at 23 ° C. The pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 4 , wherein a semiconductor wafer having a through electrode is used as a work. Claims 1 to 5 , wherein the stealth dicing pressure-sensitive adhesive sheet on which the works are laminated is used in a method for manufacturing a semiconductor device including a step of shrinking a region where the works are not laminated by heating. Adhesive sheet for stealth dicing according to any one. The pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 6, wherein the surface of the pressure-sensitive adhesive layer opposite to the base material is directly attached to the work.