WO2018083986A1

WO2018083986A1 - Adhesive sheet for stealth dicing

Info

Publication number: WO2018083986A1
Application number: PCT/JP2017/037739
Authority: WO
Inventors: 茂之山下
Original assignee: リンテック株式会社
Priority date: 2016-11-02
Filing date: 2017-10-18
Publication date: 2018-05-11
Also published as: TWI727110B; JPWO2018083986A1; KR102481281B1; JP6980680B2; CN109906504B; TW201818460A; CN109906504A; KR20190080862A

Abstract

An adhesive sheet for stealth dicing, comprising a base material and an adhesive layer laminated on to one surface side of the base material. The adhesive sheet for stealth dicing fulfills the relationship indicated by formula (1) (∆L_90°C–∆L_60°C<0 µm … (１)) when the base material is heated using a thermomechanical analysis device from 25°C to 120°C at a temperature-increasing speed of 20°C/min and the base material is pulled under a load of 0.2 g, ∆L_60°C being the amount of change in length of the base material obtained when the initial length of the base material is deducted from the length of the base material at 60°C, and ∆L_90°C being the amount of change in the length of the base material obtained when the initial length of the base material is deducted from the length of the base material at 90°C. Said adhesive sheet for stealth dicing has excellent heat shrinking properties.

Description

Stealth dicing adhesive sheet

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

Developed multilayer circuits in which a plurality of semiconductor chips are three-dimensionally stacked in response to the increase in capacity and functionality of electronic circuits. Conventionally, in such a laminated circuit, the conductive connection of the semiconductor chip is generally performed by wire bonding. However, due to the recent need for miniaturization and high functionality, the semiconductor chip can be connected without wire bonding. An effective method has been developed in which a chip is provided with an electrode (TSV) penetrating from the circuit formation surface to the back surface to directly conduct conductive connection between the upper and lower chips. As a method for manufacturing a chip with a through electrode, for example, a through hole is formed in a predetermined position of a semiconductor wafer by plasma or the like, a conductor such as copper is poured into the through hole, etching is performed, and then the surface of the semiconductor wafer And a method of providing a circuit and a through electrode. At this time, the wafer is heated.

Such ultra-thin wafers and TSV wafers are extremely fragile, and may be damaged in the back grinding 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 backside grinding and processing of the wafer are completed, the wafer is transferred from the hard support onto the dicing sheet, the periphery of the dicing sheet is fixed by a ring frame, and then the wafer is diced into a plurality of chips. Thereafter, chips are picked up from the dicing sheet.

When picking up the chip obtained by the 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. Such an expander supports the area of the dicing sheet to which the chip is adhered from the surface opposite to the surface to which the chip is adhered, and is adhered 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.

Also, when performing the above expansion, after adsorbing the dicing sheet with the adsorption table while maintaining the expanded state, the area between the area where the ring frame is affixed and the area where the chip is affixed in the dicing sheet A process (heat shrink) for heating and shrinking may be performed. Due to the shrinkage, in the dicing sheet, a force is generated to stretch the region where the chip is attached in the peripheral direction, and as a result, the chip is separated even after the dicing sheet is released from the suction by the suction table. Can be maintained.

Patent Document 1 shows a sufficient shrinkability in the heat shrinking process, and is provided with a predetermined base film as one of the problems that it does not cause problems due to looseness after the heat shrinking process, and according to a predetermined test. A wafer processing tape is disclosed in which the maximum heat shrinkage stress is a predetermined value.

Japanese Patent No. 5554118

By the way, the dicing method includes a dicing method using a dicing blade, a dicing method (stealth dicing) including forming a modified portion inside the wafer by laser irradiation and dividing the wafer by the modified portion. Exists. Among these, in the method using a dicing blade, the portion of the wafer that contacts the dicing blade is cut, and thus the obtained chips are separated by the cut width even in a state where no expansion is performed. Become. On the other hand, in stealth dicing, a modified portion is formed in a wafer by laser beam irradiation, and a plurality of chips are obtained by dividing the wafer in the modified portion. Therefore, a portion to be cut as described above does not occur on the wafer, and the obtained chips are almost in contact with each other in a state where no expansion is performed.

Therefore, when stealth dicing is performed rather than dicing using a dicing blade, it is difficult to maintain the chips in a state of being widely separated when performing the above-described heat shrink, resulting in poor pickup. Such a problem is likely to occur. Therefore, in the pressure-sensitive adhesive sheet used also for stealth dicing, the pressure-sensitive adhesive sheet is favorably contracted by heat shrink and can be maintained in a state where the chips are well separated (hereinafter, sometimes referred to as “excellent in heat shrinkability”). Is particularly required.

However, the conventional pressure-sensitive adhesive sheet such as the wafer processing tape disclosed in Patent Document 1 is not sufficiently heat-shrinkable, and in particular when stealth dicing is performed, it is not possible to keep the chips widely separated. As a result, the problem of pick-up failure is likely to occur.

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

In order to achieve the above object, first, the present invention is a pressure-sensitive adhesive sheet for stealth dicing comprising a base material and an adhesive layer laminated on one side of the base material, wherein the base material is When the substrate is pulled with a load of 0.2 g while being heated from 25 ° C. to 120 ° C. at a temperature increase rate of 20 ° C./min using a thermomechanical analyzer, the length of the substrate at 60 ° C. Then, 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 from the length of the base material at 90 ° C. When the amount of change in the length of the substrate obtained by subtracting is ΔL _{90 ° C.} , the following formula (1)
ΔL _{90 ° C.} −ΔL _{60 ° C.} <0 μm (1)
A stealth dicing pressure-sensitive adhesive sheet characterized by satisfying the above relationship is provided (Invention 1).

In the stealth dicing pressure-sensitive adhesive sheet according to the invention (Invention 1), the amount of change ΔL _{90 ° C.} and ΔL _{60 °} _C. of the length of the substrate measured using a thermomechanical analyzer has the relationship of the above formula (1). By satisfy | filling, the outstanding heat shrink property can be exhibited, and, as a result, the state which the chip | tips separated can be maintained favorably, As a result, the problem of pick-up failure can be suppressed.

In the said invention (invention 1), in the DSC curve about the said base material obtained by heating the said base material from 0 degreeC to 200 degreeC with a temperature increase rate of 10 degree-C / min using a differential scanning calorimeter, When the minimum 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 relationship (Invention 2).

In the said invention (invention 1 and 2), the said base material is a DSC curve about the said base material obtained by heating from 0 degreeC to 200 degreeC with the temperature increase rate of 10 degree-C / min using a differential scanning calorimeter. 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.} , the following formula (3)
H _{105 ° C-200 ° C} / H _{25 ° C} ≧ 1.0 (3)
It is preferable to satisfy the 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 rate of temperature increase 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.} Formula (4)
H _{105 ° C.-200 ° C./H} _{30 ° C.-100 ° C.} ≧ 0.1 (4)
It is preferable to satisfy the relationship (Invention 4).

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

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

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

The stealth dicing adhesive sheet according to the present invention is excellent in heat shrinkability.

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

1. Components of Stealth Dicing Adhesive Sheet (1) Substrate In the stealth dicing adhesive sheet according to this embodiment, the substrate is heated from 25 ° C. to 120 ° C. at a temperature rising rate of 20 ° C./min using a thermomechanical analyzer. When pulling 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 following formula (1)
ΔL _{90 ° C.} −ΔL _{60 ° C.} <0 μm (1)
Satisfy the relationship.

When a base material satisfy | fills the relationship of said Formula (1), it means that the length in 90 degreeC is shorter than the length in 60 degreeC in a base material. Therefore, when the base material is heated to a temperature such as 90 ° C. or higher and 200 ° C. or lower during heat shrinkage, the base material can be satisfactorily shrunk. Thereby, the adhesive sheet for stealth dicing provided with the base material has excellent heat shrinkability, and after heat shrink, the state in which the chips are separated from each other can be well maintained, and collision between the chips occurs. It is possible to perform a good pickup that is suppressed. The details of the measuring methods of the above-mentioned variation ΔL _{90 ° C.} and ΔL _{60 ° C.} are as described in the test examples described later.

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

In addition, as a workpiece | work in which the adhesive sheet for stealth dicing which concerns on this embodiment is used, glass members, such as semiconductor members, such as a semiconductor wafer and a semiconductor package, a glass plate, etc. are mentioned, for example. 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 chips after heat shrinking, so that the workpiece is thin and thereby the chip is easily damaged by the collision. Even if it is used, the said damage can be suppressed effectively. Therefore, as a work for which the adhesive sheet for stealth dicing is used, a semiconductor wafer having a through electrode and having a very thin thickness is generally preferable.

In the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, in a DSC curve for a base material obtained by heating from 0 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter, 30 ° C. When the minimum value of the measured value (mW) in the range from 100 to 100 ° C. is H _{30 ° C.-100 ° C.} and the measured value (mW) at _{25 ° C.} is H _{25 ° C.} , the substrate is expressed by the following formula (2 )
H _{30 ° C.-100 ° C./H} _{25 ° C.} ≦ 4.0 (2)
It is preferable to satisfy the relationship. When a base material satisfy | fills said Formula (2), the tendency for a base material not to have an endothermic peak in the temperature range of 30 degreeC to 100 degreeC increases, and melting | fusing point of a base material becomes a comparatively high thing. 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 substrate 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.

In view of the fact that the stealth dicing adhesive sheet exhibits further excellent heat resistance, the value of H _{30 ° C.-100 ° C./H} _{25 ° C.} is particularly preferably 3.0 or less. Further, the lower limit value 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 stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, a DSC curve for a base material obtained by heating from 0 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter is 105 ° C. When the minimum value of the measured value (mW) in the range from 200 to 200 ° C. is H _{105 ° C.-200 ° C.,} and the measured value (mW) at _{25 ° C.} is H _{25 ° C.} , the substrate is expressed by the following formula (3 )
H _{105 ° C-200 ° C} / H _{25 ° C} ≧ 1.0 (3)
It is preferable to satisfy the relationship. When a base material satisfy | fills said Formula (3), it becomes easy for a base material to satisfy | fill the relationship of Formula (1) mentioned above, and the adhesive sheet for stealth dicing provided with the said base material effectively has the outstanding heat shrink property. It will be demonstrated. As a result, after heat shrink, the state where the chips are separated from each other can be better maintained, and a good pickup in which 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.

The value of H _{105 ° C.-200 ° C./H} _{25 ° C.} is particularly preferably 1.1 or more from the viewpoint that the stealth dicing pressure-sensitive adhesive sheet exhibits further excellent heat resistance. 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 stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, in a DSC curve for a base material obtained by heating from 0 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min using a differential scanning calorimeter, 30 ° C. When the minimum value of the measured value (mW) in the range of 100 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. When a base material satisfy | fills said Formula (4), it becomes easy for a base material to satisfy | fill the relationship of Formula (1) mentioned above, and the adhesive sheet for stealth dicing provided with the said base material effectively has the outstanding heat shrink property. It will be demonstrated. As a result, after heat shrink, the state where the chips are separated from each other can be better maintained, and a good pickup in which collision between the chips is suppressed can be effectively performed. Furthermore, when the substrate satisfies the above formula (4), the substrate tends to have no 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 substrate 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 substrate 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 pressure-sensitive 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, more preferably 1 .5 or more is preferable. The upper limit value of the values of H _{105 ° C.-200 ° C./H} _{30 ° C.-100 ° C.} is not particularly limited, but is usually preferably 20 or less.

In the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, the tensile elastic modulus at 23 ° C. of the substrate 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 modulus is 450 MPa or less, the base material is easily contracted by heating, and therefore, it is possible to effectively maintain the semiconductor chip and the glass chip in a separated state after the heat shrink. 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 including the base material has excellent workability and handling properties. In addition, the detail of the measuring method of the said tensile elasticity modulus is as describing in the test example mentioned later.

The material of the substrate is not particularly limited as long as it satisfies the relationship of the above formula (1) relating to measurement by a thermomechanical analyzer and exhibits a desired function in the use process of 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 can exhibit good permeability to the energy rays irradiated for curing the pressure-sensitive adhesive layer. preferable.

The base material is preferably a resin film mainly composed of a resin-based material. Specific examples thereof include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, and an ethylene-norbornene copolymer. Film, polyolefin film such as norbornene resin film; ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid methyl copolymer film, other ethylene- (meth) acrylic acid ester copolymer film Ethylene copolymer films such as ethylene-vinyl acetate copolymer films; polyvinyl chloride films such as polyvinyl chloride films and vinyl chloride copolymer films; (meth) acrylic acid ester copolymer films; polyurethane films Beam; polystyrene films; fluororesin film; polyimide film; and a polycarbonate film. In the polyolefin-based film, the polyolefin may be a block copolymer or a random copolymer. Examples of the polyethylene film include a low density polyethylene (LDPE) film, a linear low density polyethylene (LLDPE) film, and a high density polyethylene (HDPE) film. In addition, modified films such as these crosslinked films and ionomer films are also used. The substrate may be a laminated film in which a plurality of the above-described films are laminated. In this laminated film, the material constituting each layer may be the same or different. In addition, “(meth) acrylic acid” in the present specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the substrate, among the above films, from the viewpoint of easily satisfying the relationship of the above formula (1) relating to measurement by a thermomechanical analyzer, a low density polyethylene film, a linear low density polyethylene film, a polypropylene film of a random copolymer (random) Polypropylene film) or ethylene-methacrylic acid copolymer film is preferably used.

The substrate may contain various additives such as a flame retardant, a plasticizer, an antistatic agent, a lubricant, an antioxidant, a colorant, an infrared absorber, and an ion scavenger. The content of these additives is not particularly limited, but is preferably in a range where the base material exhibits a desired function.

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

The thickness of the substrate is preferably 450 μm or less, particularly preferably 400 μm or less, and more preferably 350 μm or less. The thickness is preferably 20 μm or more, particularly preferably 25 μm or more, and more 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 well separated and maintained. Moreover, when the thickness of the base material is 20 μm or more, the base material has good rigidity, and the stealth dicing pressure-sensitive adhesive sheet can effectively support the workpiece.

(2) Pressure-sensitive 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 use process of the pressure-sensitive adhesive sheet for stealth dicing. When the pressure-sensitive adhesive sheet for stealth dicing includes the pressure-sensitive adhesive layer, the workpiece can be easily adhered 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. As the non-energy ray curable pressure-sensitive adhesive, those having desired adhesive strength and removability are preferable. For example, acrylic pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, and polyester-based pressure-sensitive adhesive Polyvinyl ether-based pressure-sensitive adhesives can be used. Among these, an acrylic pressure-sensitive adhesive that can effectively suppress dropping of a semiconductor chip or 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 its adhesive strength decreases. Therefore, when it is desired to separate the semiconductor chip and the adhesive sheet for stealth dicing, it can be easily separated by irradiating energy rays. Can be made.

The energy ray-curable pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be mainly composed of a polymer having energy ray-curability, or a non-energy ray-curable polymer (polymer not having energy ray-curability). And a mixture of a monomer and / or an oligomer having at least one energy ray curable group. Further, it may be a mixture of a polymer having energy ray curable properties and a non-energy ray curable polymer, a polymer having energy ray curable properties and a monomer having at least one energy ray curable group and / or It may be a mixture with an oligomer or a mixture of these three.

First, the case where the energy ray-curable pressure-sensitive adhesive is composed mainly of a polymer having energy ray-curability will be described below.

The polymer having energy ray curability is a (meth) acrylic acid ester (co) polymer (A) (hereinafter referred to as “energy ray”) in which a functional group having energy ray curability (energy ray curable group) is introduced into the side chain. It may be referred to as “curable polymer (A)”). This energy beam 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.

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) contains 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 has

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl ( Examples thereof include meth) acrylate and 4-hydroxybutyl (meth) acrylate, and these 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 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.

Examples of the (meth) acrylic acid ester monomer constituting the acrylic copolymer (a1) include an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, and an alicyclic structure in the molecule, for example. The monomer (alicyclic structure-containing monomer) is preferably used.

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

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

Furthermore, the acrylic copolymer (a1) preferably contains 50% by mass or more, particularly preferably 60% by mass or more, and further preferably 70% by mass of a structural unit derived from a (meth) acrylic acid ester monomer or a derivative thereof. It contains in the above ratio. The acrylic copolymer (a1) preferably contains 99% by mass or less, particularly preferably 95% by mass or less, and more preferably 90% by mass of a structural unit derived from a (meth) acrylic acid ester monomer or a derivative thereof. Contains 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 in a conventional manner. Dimethylacrylamide, vinyl formate, vinyl acetate, styrene and the like may be copolymerized.

By reacting the acrylic copolymer (a1) having the functional group-containing monomer unit with an unsaturated group-containing compound (a2) having a functional group bonded to the functional group, an energy beam curable polymer (A ) Is obtained.

The functional group of the unsaturated group-containing compound (a2) can be appropriately selected according to the type of 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. When the functional group that the system copolymer (a1) has is an epoxy group, the functional group that the unsaturated group-containing compound (a2) has is preferably an amino group, a carboxy group, or an aziridinyl group.

The unsaturated group-containing compound (a2) contains at least one, preferably 1-6, more preferably 1-4, energy-polymerizable carbon-carbon double bonds in one molecule. ing. Specific examples of such unsaturated group-containing compound (a2) include, for example, 2-methacryloyloxyethyl isocyanate, meta-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate, allyl isocyanate, 1,1- ( Bisacryloyloxymethyl) ethyl isocyanate; acryloyl monoisocyanate compound obtained by reaction of diisocyanate compound or polyisocyanate compound with hydroxyethyl (meth) acrylate; diisocyanate compound or polyisocyanate compound, 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.

The unsaturated group-containing compound (a2) is preferably at least 50 mol%, particularly preferably at least 60 mol%, more preferably 70 mol, based on the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). % Is used at a rate of at least%. In addition, the unsaturated group-containing compound (a2) is preferably 95 mol% or less, particularly preferably 93 mol% or less, more preferably, relative to the number of moles of the functional group-containing monomer of the acrylic copolymer (a1). It is used at a ratio 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) Depending on the combination, the reaction temperature, pressure, solvent, time, presence / absence of catalyst, and type of catalyst 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), so that the unsaturated group is contained in the acrylic copolymer (a1). It introduce | transduces into a side chain and an energy-beam curable polymer (A) is obtained.

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 more preferably 200,000 or more. Is preferred. The weight average molecular weight (Mw) is preferably 1.5 million or less, and particularly preferably 1 million or less. In addition, the weight average molecular weight (Mw) in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography method (GPC method).

Even when the energy ray curable adhesive is mainly composed of an energy ray curable polymer such as an energy ray curable polymer (A), the energy ray curable adhesive is an energy ray curable monomer. And / or the oligomer (B) may further be contained.

As the energy ray-curable monomer and / or oligomer (B), for example, an ester of a polyhydric alcohol and (meth) acrylic acid or the like 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, trimethylolpropane tri (meth) acrylate, penta Erythritol 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 Polyfunctional acrylic esters such as di (meth) acrylate and dimethyloltricyclodecane di (meth) acrylate, polyester oligo (meth) acrylate, polyurethane oligo (meta Acrylate, and the like.

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

Here, when using ultraviolet rays 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, benzoin methyl benzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone, 1-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, β-chloranthraquinone, (2,4 6-trimethylbenzyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate, oligo {2-hydroxy-2-me Le-1- [4- (1-propenyl) phenyl] propanone}, and 2,2-dimethoxy-1,2-and the like. These may be used alone or in combination of two or more.

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

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

Examples of the non-energy ray curable polymer component or oligomer component (D) include polyacrylates, polyesters, polyurethanes, polycarbonates, polyolefins, etc., and polymers or oligomers having a weight average molecular weight (Mw) of 3000 to 2.5 million. Is preferred. By mix | blending the said component (D) with energy-beam curable adhesive, the adhesiveness and peelability before hardening, the intensity | strength after hardening, the adhesiveness with another layer, storage stability, etc. can be improved. The compounding quantity of the said component (D) is not specifically limited, It determines suitably in the range of more than 0 mass part and 50 mass parts or less with respect to 100 mass parts of energy-beam curable copolymers (A).

As the crosslinking agent (E), a polyfunctional compound having reactivity with the functional group of the energy beam 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, A reactive phenol resin etc. can be mentioned.

The amount of the crosslinking agent (E) is preferably 0.01 parts by mass or more, particularly 0.03 parts by mass or more, with respect to 100 parts by mass of the energy ray curable copolymer (A). More preferably, it is 0.04 parts by mass or more. The amount of the crosslinking agent (E) is preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, with respect to 100 parts by mass of the energy ray curable copolymer (A). Furthermore, it is preferable that it is 3.5 mass parts or less.

Next, the case where the energy beam curable pressure-sensitive adhesive is mainly composed of a mixture of a non-energy beam curable polymer component and a monomer and / or oligomer having at least one energy beam curable group will be described below. .

As the non-energy ray curable polymer component, for example, the same components as the acrylic copolymer (a1) described above 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 blending ratio of the non-energy ray curable polymer component and 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 of the monomer and / or oligomer having an energy ray-curable group is preferably 1 part by mass or more, and particularly preferably 60 parts by mass or more. The blending ratio is preferably not more than 200 parts by mass of monomers and / or oligomers 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 crosslinking agent (E) can be appropriately blended as described above.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, particularly preferably 2 μm or more, and more 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, the adhesive sheet for stealth dicing exhibits a good adhesive force, and the peeling of the workpiece at an unintended stage can be effectively suppressed. . Moreover, it is suppressed that the adhesive force of the adhesive sheet for stealth dicing becomes too high because the thickness of an adhesive layer is 50 micrometers or less, and generation | occurrence | production of a pick-up defect, etc. can be suppressed effectively.

(3) Release sheet In the adhesive sheet for stealth dicing according to this embodiment, a release sheet is laminated on the surface for the purpose of protecting the adhesive surface until the adhesive surface in the adhesive layer is applied to the workpiece. Also good. The configuration of the release sheet is arbitrary, and examples include a release film of a plastic film 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, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, a silicone-based material that is inexpensive and provides stable performance is preferable. Although there is no restriction | limiting in particular about the thickness of a peeling sheet, Usually, they are 20 micrometers or more and 250 micrometers or less.

2. Production method of stealth dicing pressure-sensitive adhesive sheet In the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, the base material production method is as long as the obtained base material satisfies the relationship of the above formula (1) relating to measurement by a thermomechanical analyzer. There is no particular limitation. For example, using the materials described above, a substrate 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.

In the stealth dicing pressure-sensitive adhesive sheet according to this embodiment, the method for forming the pressure-sensitive adhesive layer is not particularly limited. For example, an adhesive sheet for stealth dicing 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 adhesive composition constituting the pressure-sensitive adhesive layer and, if desired, a coating liquid further containing a solvent or a dispersion medium are prepared, and a release-treated surface of the release sheet (hereinafter referred to as “release surface”) .) On top, a coating film is formed by applying the coating solution with a die coater, curtain coater, spray coater, slit coater, knife coater, etc., 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 may contain a component for forming the pressure-sensitive adhesive layer as a solute or 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 stealth dicing adhesive sheet is attached to a workpiece.

When the coating liquid for forming the pressure-sensitive adhesive layer contains a cross-linking agent, it is possible to change the above drying conditions (temperature, time, etc.) What is necessary is just to advance the crosslinking reaction of an energy-beam curable polymer (A) or a non-energy-beam curable polymer component, and a crosslinking agent (E), and to form a crosslinked structure with a desired existing density in an adhesive layer. In order to sufficiently proceed with this crosslinking reaction, after the pressure-sensitive adhesive layer is laminated on the base material by the above-described method, the obtained pressure-sensitive adhesive sheet for stealth dicing is several times in an environment of, for example, 23 ° C. and a relative humidity of 50%. Curing may be performed such as standing for days.

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

3. Method for Using Stealth Dicing Adhesive Sheet The stealth dicing adhesive sheet according to this embodiment can be used for stealth dicing. Moreover, the adhesive sheet for stealth dicing which concerns on this embodiment can be used for the manufacturing method of a semiconductor device provided with the process of stealth dicing.

As described above, the adhesive sheet for stealth dicing according to the present embodiment can suppress the collision between chips after heat shrinking, and thus is suitably used for a workpiece that is thin and thereby easily breaks the chip. 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. The back grinding can be performed by a general method.

Subsequently, the semiconductor wafer on which back grinding has been completed is transferred from the hard support to the adhesive sheet for stealth dicing. At this time, the surface on the adhesive layer side of the adhesive sheet for stealth dicing is attached to the back-ground 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, And a method of sliding a hard support from a semiconductor wafer, a method of decomposing an adhesive by laser light irradiation, and the like. In addition, after a hard support body is isolate | separated from a semiconductor wafer, the peripheral part in the adhesive sheet for stealth dicing is affixed with respect to a ring frame.

Subsequently, a process of cleaning the semiconductor wafer laminated on the stealth dicing adhesive sheet with a solvent is performed. Thereby, the adhesive agent remaining on the semiconductor wafer can be removed. The cleaning can be performed by a general method, for example, a method of immersing a laminate of an adhesive sheet for stealth dicing and a semiconductor wafer in a solvent, a frame slightly larger than the semiconductor wafer so as to surround the wafer. And a method of placing the solution on the adhesive sheet for stealth dicing and introducing a solvent into the frame.

Subsequently, if necessary, another semiconductor wafer may be laminated on the semiconductor wafer laminated on the stealth dicing adhesive sheet. At this time, the semiconductors can be fixed using an adhesive or the like, for example, can be fixed by a non-conductive adhesive film (NCF). You may repeat the lamination | stacking of a semiconductor wafer until it becomes the required number of lamination | stacking. Such stacking of semiconductor wafers is preferably performed when a TSV wafer is used as a semiconductor wafer and a laminated circuit is manufactured.

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

Subsequently, the semiconductor wafer is divided at a modified portion formed by stealth dicing to obtain a plurality of semiconductor chips. The division can be performed, for example, by placing a laminate of an adhesive sheet for stealth dicing and a semiconductor wafer in an expanding apparatus and expanding in a 0 ° C. to room temperature environment.

Subsequently, the adhesive sheet for stealth dicing is expanded again. The expansion is performed mainly for the purpose of separating the obtained semiconductor chips. Furthermore, the adhesive sheet for stealth dicing is adsorbed by an adsorption table while maintaining the expanded state. The expanding 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 apparatus, and the suction table used can also be performed using a general one.

Subsequently, with the stealth dicing adhesive sheet adsorbed on the adsorption table, the region of the stealth dicing adhesive sheet in which the obtained semiconductor chips are laminated is contracted by heating (heat shrink). . Specifically, the region between the region where the semiconductor chip is laminated in the stealth dicing adhesive sheet and the region where the ring frame is pasted in the stealth dicing adhesive sheet is heated to shrink the region. As heating conditions at this time, the temperature of the stealth dicing pressure-sensitive adhesive sheet is preferably 90 ° C. or higher. Moreover, it is preferable that the temperature of the adhesive sheet for stealth dicing shall be 200 degrees C or less. In the stealth dicing pressure-sensitive adhesive sheet according to the present embodiment, the amount of change ΔL _{90 ° C.} and ΔL _{60 °} _C. of the length of the substrate measured using the thermomechanical analyzer satisfies the relationship of the above-described formula (1). The substrate can be favorably shrunk by heating. Thereby, as will be described later, even after releasing the stealth dicing adhesive sheet from the suction by the suction table, the state where the semiconductor chips are separated from each other can be maintained well, and the semiconductor chip is picked up well. Can do.

Subsequently, the adhesive sheet for stealth dicing is released from the suction by the suction table described above. In the heat shrink process, the area between the area where the semiconductor chip is laminated in the pressure-sensitive adhesive sheet for stealth dicing and the area where the ring frame is affixed in the pressure-sensitive adhesive sheet for stealth dicing contracted, so that the pressure-sensitive adhesive sheet for stealth dicing Then, the force which stretches the area | region where the semiconductor chip was affixed in the peripheral part direction has arisen. As a result, it is possible to maintain a state where the semiconductor chips are separated from each other even after being released from the suction by the suction table.

Thereafter, individual semiconductor chips are picked up from the stealth dicing adhesive sheet in a state of being separated from the adjacent semiconductor chips. This pickup can be performed by a general method using a general apparatus. As described above, the stealth dicing pressure-sensitive adhesive sheet according to this embodiment can maintain the semiconductor chips in a well-separated state as a result of exhibiting excellent heat shrink properties, thereby improving the pickup. It can be carried out.

The embodiment described above is described for facilitating understanding of the present invention, and is 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, other layers may be provided between the substrate and the pressure-sensitive adhesive layer, or on the surface of the substrate opposite to the pressure-sensitive adhesive layer.

Hereinafter, the present invention will be described more specifically 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 substrate A resin composition containing low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd., product name “Sumikasen F-412-1”) is transferred to a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name “ Extrusion was performed by a “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 acrylate (BA), 10 parts by mass of methyl methacrylate (MMA) and 28 parts by mass of 2-hydroxyethyl acrylate (HEA) were 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 give an energy beam curable polymer ( A) was obtained. When the molecular weight of this energy beam 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 (in terms of solid content, the same applies hereinafter) and 1-hydroxycyclohexyl phenyl ketone (product name “Irgacure 184” manufactured by BASF) as a photopolymerization initiator Part and 1.0 part by mass of tolylene diisocyanate (manufactured by Tosoh Corporation, product name “Coronate L”) as a crosslinking agent were mixed in a solvent to obtain a pressure-sensitive adhesive composition.

(3) Formation of pressure-sensitive adhesive layer Release surface of a release sheet (product name “SP-PET381031”, manufactured by Lintec Corporation) in which a silicone release agent layer is formed on one side of a 38 μm-thick polyethylene terephthalate (PET) film On the other hand, the said adhesive composition was apply | coated and dried by heating, and the 20-micrometer-thick adhesive layer was formed on the peeling sheet.

(4) Manufacture of adhesive sheet for stealth dicing By sticking the surface opposite to the release sheet of the adhesive layer formed in the step (3) and one side of the substrate prepared in the step (1). Thus, an adhesive sheet for stealth dicing was obtained.

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

Example 3
Resin composition containing low-density polyethylene as a base material (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”). A stealth dicing pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that a substrate having a thickness of 70 μm obtained by molding was used.

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

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

Example 6
Resin composition containing ethylene-methacrylic acid copolymer (product name “Nucleel NH903C” manufactured by Mitsui Dupont Polychemical Co., Ltd.) as a base material and a small T-die extruder (product name “Laboratory” manufactured by Toyo Seiki Seisakusho Co., Ltd.) A pressure-sensitive adhesive sheet for stealth dicing was produced in the same manner as in Example 1 except that a substrate having a thickness of 70 μm obtained by extrusion molding using a plastmill ”) was used.

[Comparative Example 1]
An 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 the substrate.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-reduced weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

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

[Test Example 2] (Measurement with a differential scanning calorimeter)
4.0 mg was cut out from the base material produced in the Example and the comparative example, and it was set as the 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 (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 measured value (mW) in the range from 30 ° C. to 100 ° C. is H _{30 ° C.-100 °} C. To 200 ° C., the minimum value of the measured value (mW) was 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 with a thermomechanical analyzer)
The base material produced by the Example and the comparative example was cut into the size of 4.5 mm x 20 mm, and it was set as the measurement sample. The measurement sample was placed on a thermomechanical analyzer (manufactured by BRUKER, product name “TMA4000SA”) with a distance between chucks 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 major axis direction with a load of 0.2 g. And the distance between chuck | zippers of the measurement sample in 60 degreeC and 90 degreeC was measured, respectively.

Then, the amount of change ΔL _{60 ° C.} (μm) in the distance between the chucks of the measurement sample was calculated by subtracting the initial chuck distance from the distance between the chucks of the measurement sample at _{60 ° C.} Further, the amount of change ΔL _{90 ° C.} (μm) in the distance between chucks of the measurement sample was calculated by subtracting the initial chuck distance from the distance between chucks of the measurement sample at _{90 ° C.} 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 the release sheet was peeled from the stealth dicing adhesive sheet produced in the examples and comparative examples, the substrate side surface of the stealth dicing adhesive sheet was placed on a multi-wafer mounter (product name “RAD-2700 F, manufactured by Lintec Corporation”). / 12 ") was adsorbed for 2 minutes. During the adsorption, the adsorption table was heated to 70 ° C.

After the lapse of 2 minutes, the suction by the suction table was stopped, and then the transport means provided in the multi-wafer mounter was driven so that the stealth dicing adhesive sheet was separated from the suction table. At this time, the separation was performed satisfactorily, and "O" was able to convey the stealth dicing adhesive sheet without any problem, and the stealth dicing adhesive sheet was slightly adhered to the porous table, but the stealth dicing adhesive sheet “△” indicates that the material could be conveyed, and “×” indicates that the stealth dicing adhesive sheet was in close contact with the porous table and could not be conveyed, and the heat resistance of the stealth dicing adhesive sheet was evaluated. did. The results are shown in Table 1.

The above heat resistance evaluation was also performed when the adsorption 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 from the stealth dicing adhesive sheet produced in the examples and comparative examples, and the multi-wafer mounter (product name “RAD-2700 F / 12”, manufactured by Lintec Corporation) was applied to the exposed adhesive surface of the 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 affixed on the adhesive sheet for stealth dicing is irradiated with laser light having a wavelength of 1342 nm using a laser saw (manufactured by DISCO, product name “DFL7361”), and the resulting chip size is 8 mm. A modified portion was formed in the silicon wafer so as to be 8 mm.

Next, the silicon wafer and ring frame after the laser beam irradiation, to which the adhesive sheet for stealth dicing was attached, were placed on a die separator (manufactured by Disco Corporation, product name “DDS2300”), and the withdrawal speed was 100 mm / Second (expanded) with an expanding amount of 10 mm. As a result, the semiconductor wafer was divided at the modified portion, and a plurality of semiconductor chips each having a chip size of 8 mm × 8 mm were obtained.

Subsequently, an adhesive sheet for stealth dicing was expanded at a withdrawal speed of 1 mm / second and an expanding amount of 7 mm. Furthermore, after the adhesive sheet for stealth dicing was adsorbed by the adsorption table in the expanded state, the area between the area where the semiconductor chip was adhered and the area where the ring frame was adhered in the adhesive sheet for stealth dicing was heated. As 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 adsorption table supporting the stealth dicing adhesive sheet and the heater was set to 13 mm. Thereby, the adhesive sheet for stealth dicing was heated to about 180 degreeC.

Thereafter, the adhesive sheet for stealth dicing was released from the adsorption by the adsorption table, the distance between adjacent semiconductor chips was measured at five points, and the average value was calculated. And the case where the said average value is 20 micrometers or more was set to "(circle)", and the case where it is less than 20 micrometers was set to "x", and heat shrink property was evaluated. The results are shown in Table 1.

As can be seen from Table 1, the stealth dicing adhesive sheets obtained in the examples were excellent in heat shrink properties. In addition, the stealth dicing adhesive sheets obtained in Examples 1 to 3 were 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

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,
In the case where the substrate is pulled with a load of 0.2 g while being heated 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 the time of ° C. is ΔL 60 ° C. , and the base material is calculated from the length of the base material at 90 ° C. When the amount of change in the length of the base material obtained by reducing the initial length is ΔL 90 ° C. , the following formula (1)
ΔL 90 ° C. −ΔL 60 ° C. <0 μm (1)
An adhesive sheet for stealth dicing characterized by satisfying the above relationship.
In the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min using a differential scanning calorimeter, the base material is in the range of 30 ° C. to 100 ° C. When the minimum measured value is 30 ° C-100 ° C and the measured value at 25 ° C is 25 ° C , the following formula (2)
H 30 ° C.-100 ° C./H 25 ° C. ≦ 4.0 (2)
The adhesive sheet for stealth dicing according to claim 1, wherein the relationship is satisfied.
In the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min using a differential scanning calorimeter, the base material is in the range of 105 ° C. to 200 ° C. 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)
The pressure-sensitive adhesive sheet for stealth dicing according to claim 1 or 2, wherein the relationship is satisfied.
In the DSC curve for the base material obtained by heating from 0 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min using a differential scanning calorimeter, the base material is in the range of 30 ° C. to 100 ° C. 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)
The pressure-sensitive adhesive sheet for stealth dicing according to any one of claims 1 to 3, wherein the relationship is satisfied.
The adhesive sheet for stealth dicing according to any one of claims 1 to 4, wherein the base material has a tensile elastic modulus at 23 ° C of 50 MPa or more and 450 MPa or less.
The adhesive sheet for stealth dicing according to any one of claims 1 to 5, wherein the workpiece is a semiconductor wafer having through electrodes.
7. The method of manufacturing a semiconductor device according to claim 1, wherein the stealth dicing pressure-sensitive adhesive sheet having a workpiece laminated thereon is used in a method for manufacturing a semiconductor device including a step of shrinking a region where the workpiece is not laminated by heating. The adhesive sheet for stealth dicing according to any one of the above.