JP2014070183A - Adhesive sheet for manufacturing semiconductor device, and method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet for manufacturing a semiconductor device and a method for manufacturing a semiconductor device capable of properly fixing a semiconductor wafer on a pedestal, as well as easily separating the pedestal from the semiconductor wafer.SOLUTION: An adhesive sheet for manufacturing a semiconductor device is used for fixing a semiconductor wafer on a pedestal, and a first adhesive layer and a second layer with adhesive strength lower than the first adhesive layer are laminated therein. Further, a method for manufacturing a semiconductor device uses the adhesive sheet. Further, a step (A) of adhering a semiconductor wafer onto an adhesive sheet (a); a step (B) of adhering the pedestal onto the adhesive sheet (b); and a step (C) of laminating the adhesive sheet (a) of the semiconductor wafer with the adhesive sheet (a), obtained by the step (A), and the adhesive sheet (b) of a pedestal with the adhesive sheet (b), obtained by the step (B), are included. One of the adhesive sheets (a) and (b) has adhesive strength lower than the other.

Description

The present invention relates to an adhesive sheet for manufacturing a semiconductor device and a method for manufacturing a semiconductor device.

Conventionally, in a semiconductor device manufacturing process, after a semiconductor wafer is temporarily fixed on a pedestal, a predetermined process such as back grinding is performed on the semiconductor wafer, and then the pedestal is separated from the semiconductor wafer. There is. In such a process, it is important that the pedestal can be easily separated from the semiconductor wafer.

As a method for temporarily fixing a semiconductor wafer on a pedestal, it is known to use a liquid adhesive. The liquid adhesive is applied to the semiconductor wafer or the pedestal by spin coating.

In Patent Document 1, a device wafer as a first substrate and a carrier substrate as a second substrate are pressure-bonded through a filling layer that does not form a strong adhesive bond, and a bonding material is filled into the periphery of the filling layer. A method of forming an edge bond by curing and bonding the first substrate and the second substrate is disclosed.

Patent Document 2 discloses a bonding composition layer containing a compound selected from the group consisting of oligomers and polymers, selected from the group consisting of polymers and oligomers of imides, amidoimides and amidoimide-siloxanes. A method of joining the first substrate and the second substrate via the above is disclosed.

Special table 2011-510518 gazette Special table 2010-53385 gazette

The filling layer described in Patent Document 1 and the bonding composition layer described in Patent Document 2 are applied by spin coating or the like. However, if a layer with a thickness of 10 μm or more necessary for adhesion is formed by coating, the coated surface is generally rough, the unevenness followability is poor, the desired adhesive force cannot be obtained, and the semiconductor wafer is sufficiently fixed to the pedestal. There are cases where it is not possible.

In addition, when applying by spin coating, there is a problem that most of the material is wasted. In addition, since the material has a high viscosity for bonding, labor is required to remove the dirt on the spin coater.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an adhesive sheet for manufacturing a semiconductor device that can satisfactorily fix a semiconductor wafer to a pedestal and easily separate the pedestal from the semiconductor wafer. It is another object of the present invention to provide a method for manufacturing a semiconductor device that can satisfactorily fix a semiconductor wafer to a pedestal and can easily separate the pedestal from the semiconductor wafer.

The present inventor has found that the above-mentioned problems can be solved by adopting the following configuration, and has completed the present invention.

1st this invention is the adhesive sheet for semiconductor device manufacture used in order to fix a semiconductor wafer to a base, Comprising: The 1st adhesive bond layer and the 2nd layer whose adhesive force is lower than the said 1st adhesive bond layer And an adhesive sheet for manufacturing a semiconductor device.

Since the adhesive sheet is in the form of a sheet, the surface can be formed more uniformly than when the adhesive layer is formed by spin coating. Furthermore, the material is not wasted like spin coating. Moreover, since it is a sheet form, it can be used simply.

Moreover, the 1st adhesive bond layer and the 2nd layer whose adhesive force is lower than the said 1st adhesive bond layer are laminated | stacked. Since it has a 1st adhesive bond layer, a semiconductor wafer can be favorably fixed to a base. Since the second layer having a lower adhesive force than the first adhesive layer is provided, the pedestal can be easily separated from the semiconductor wafer by an external force.

In the first aspect of the present invention, the adhesive strength of the first adhesive layer and the adhesive strength of the second layer are the 90 ° peel peeling from the silicon wafer under the conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min. I say power. In addition, in the adhesive sheet which fixes a semiconductor wafer to a base by performing imidation, thermosetting, etc., the 90 degree peel peeling force in the state (for example, after imidation or after thermosetting) fixed to a silicon wafer is said. Specifically, it can be measured by the method described in the examples.

The first aspect of the present invention also relates to a method for manufacturing a semiconductor device, comprising: a step of fixing a semiconductor wafer to a pedestal using the adhesive sheet for manufacturing a semiconductor device; and a step of separating the pedestal from the semiconductor wafer.

The step of fixing the semiconductor wafer to the pedestal using the adhesive sheet for manufacturing a semiconductor device includes attaching the semiconductor wafer to the first adhesive layer and attaching the pedestal to the second layer. Preferably, the step of fixing the semiconductor wafer to the pedestal.

The first adhesive layer has a higher adhesive force than the second layer, and is excellent in unevenness followability such as the surface of a semiconductor wafer. According to the said structure, since a 1st adhesive bond layer can track the unevenness | corrugation on the surface of a semiconductor wafer, a semiconductor wafer can be favorably fixed to a base. On the other hand, since the 2nd layer whose adhesive force is lower than a 1st adhesive bond layer contacts a base, it is easy to peel an adhesive sheet from a base. In addition, there is little adhesive residue on the pedestal and it is easy to reuse the pedestal.

2nd this invention, the process (A) which affixes a semiconductor wafer to an adhesive sheet (a), the process (B) which affixes a base to an adhesive sheet (b), and the adhesion | attachment obtained by the said process (A) Bonding the adhesive sheet (a) of the semiconductor wafer with the sheet (a), and the adhesive sheet (b) of the base with the adhesive sheet (b) obtained by the step (B) (C), The present invention relates to a method of manufacturing a semiconductor device in which one adhesive force of the adhesive sheets (a) and (b) is lower than the other.

Since the sheet-like adhesive sheets (a) and (b) are used, materials are not wasted unlike spin coating.

Moreover, one adhesive force of the said adhesive sheet (a) and (b) is lower than the other. For this reason, it is easy to separate the pedestal from the semiconductor wafer. In addition, since the adhesive sheet having a relatively high adhesive force is used, the semiconductor wafer can be satisfactorily fixed to the pedestal.

In the second aspect of the present invention, the adhesive strength of the adhesive sheet (a) and the adhesive strength of the adhesive sheet (b) are 90 ° peel to a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min. Refers to peeling force. In the case where the adhesive sheets (a) and (b) are bonded by imidization or thermosetting, 90 ° in a state fixed to the silicon wafer (for example, after imidization or thermosetting). Refers to peel strength. Specifically, it can be measured by the method described in the examples.

It is preferable that the adhesive strength of the adhesive sheet (b) is lower than that of the adhesive sheet (a).

According to the said structure, an adhesive sheet (a) has higher adhesive force than an adhesive sheet (b), and is excellent in uneven | corrugated followable | trackability, such as a semiconductor wafer surface. Since the adhesive sheet (a) can follow the irregularities on the surface of the semiconductor wafer, the semiconductor wafer can be satisfactorily fixed to the pedestal. On the other hand, since the adhesive sheet (b) having an adhesive force lower than that of the adhesive sheet (a) is in contact with the pedestal, the adhesive sheet (b) is easily peeled from the pedestal. In addition, there is little adhesive residue on the pedestal and it is easy to reuse the pedestal.

ADVANTAGE OF THE INVENTION According to this invention, while a semiconductor wafer can be favorably fixed to a base, a base can be easily isolate | separated from a semiconductor wafer.

2 is a schematic cross-sectional view of an adhesive sheet according to Embodiment 1. FIG. It is a cross-sectional schematic diagram of the adhesive sheet of Embodiment 2. It is a schematic diagram which shows a mode that the semiconductor wafer was affixed on the adhesive sheet of Embodiment 1. FIG. It is a schematic diagram which shows a mode that the semiconductor wafer was fixed to the base using the adhesive sheet of Embodiment 1. FIG. It is a cross-sectional schematic diagram of an adhesive sheet (a). It is a schematic diagram which shows a mode that the semiconductor wafer was affixed on the adhesive sheet (a). It is a cross-sectional schematic diagram of an adhesive sheet (b). It is a schematic diagram which shows a mode that the base was affixed on the adhesive sheet (b). It is a schematic diagram which shows a mode that the semiconductor wafer was fixed to the base using the adhesive sheets (a) and (b).

[Adhesive sheet]
In the adhesive sheet for manufacturing a semiconductor device according to the first aspect of the present invention, a first adhesive layer and a second layer having an adhesive force lower than that of the first adhesive layer are laminated.

Hereinafter, the adhesive sheet of the first invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an adhesive sheet 7 according to the first embodiment. As shown in FIG. 1, the adhesive sheet 7 is formed by laminating a first adhesive layer 70 and a second layer 71. The adhesive force of the second layer 71 is lower than the adhesive force of the first adhesive layer 70.

Since the adhesive sheet 7 has the first adhesive layer 70, the semiconductor wafer can be satisfactorily fixed to the pedestal. Moreover, since it has the 2nd layer 71 whose adhesive force is lower than the 1st adhesive bond layer 70, a base can be easily isolate | separated from a semiconductor wafer with external force.

The thickness of the 1st adhesive bond layer 70 is not specifically limited, For example, it is 10 micrometers or more, Preferably it is 50 micrometers or more. When the thickness is 10 μm or more, the unevenness on the surface of the semiconductor wafer can be followed, and the adhesive sheet 7 can be filled without a gap. Moreover, the thickness of the 1st adhesive bond layer 70 is 500 micrometers or less, for example, Preferably it is 300 micrometers or less. When the thickness is 500 μm or less, variation in thickness and shrinkage / expansion during heating can be suppressed or prevented.

The thickness of the 2nd layer 71 is not specifically limited, For example, it is 1 micrometer or more, Preferably it is 5 micrometers or more. When it is 1 μm or more, it is easy to bond to the pedestal. The thickness of the second layer 71 is, for example, 500 μm or less, and preferably 300 μm or less. When the thickness is 500 μm or less, variation in thickness and shrinkage / expansion during heating can be suppressed or prevented.

Since the first adhesive layer 70 generally has a lower elastic modulus than the second layer 71, the surface of the first adhesive layer 70 is likely to swell during formation. From such a viewpoint, it is preferable to make the first adhesive layer 70 thin and the second layer 71 thick. On the other hand, since the first adhesive layer 70 generally has a higher glass transition temperature than the second layer 71, the first adhesive layer 70 has a large shrinkage during formation. From such a viewpoint, it is preferable to make the first adhesive layer 70 thick and the second layer 71 thin.

The shape of the adhesive sheet 7 when viewed from above is not particularly limited, but is usually circular.

The adhesive force of the second layer 71 is not particularly limited as long as it is lower than the adhesive force of the first adhesive layer 70. The adhesive strength of the second layer 71 is preferably, for example, a 90 ° peel peel force for a silicon wafer under a temperature of 23 ± 2 ° C. and a peel speed of 300 mm / min is less than 0.30 N / 20 mm. More preferably, it is 20 N / 20 mm or less. When it is less than 0.30 N / 20 mm, the pedestal can be easily separated from the semiconductor wafer. On the other hand, the lower limit of the 90 ° peel strength is preferably 0.001 N / 20 mm or more, more preferably 0.005 N / 20 mm or more, and still more preferably 0.010 N / 20 mm or more. When it is 0.001 N / 20 mm or more, the semiconductor wafer can be fixed to the pedestal well, and back grinding and the like can be performed well.

The adhesive force of the first adhesive layer 70 is preferably, for example, a 90 ° peel peel force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel speed of 300 mm / min is 0.30 N / 20 mm or more. 0.40 N / 20 mm or more is more preferable. When it is 0.30 N / 20 mm or more, the semiconductor wafer can be satisfactorily fixed to the pedestal, and back grinding and the like can be favorably performed. The upper limit of the 90 ° peel peel force is not particularly limited and is preferably as large as possible. For example, it is 30 N / 20 mm or less, preferably 20 N / 20 mm or less.

As shown in FIG. 2, the adhesive sheet of 1st this invention may be formed with another layer (Embodiment 2). FIG. 2 is a schematic cross-sectional view of an adhesive sheet including a third layer. The adhesive sheet 7 in FIG. 2 is formed by stacking a third layer 75, a second layer 71, and a first adhesive layer 70.

The adhesive force of the third layer 75 is preferably lower than the adhesive force of the first adhesive layer 70. Thereby, when the 3rd layer 75 of the adhesive sheet 7 is affixed on a base, the adhesive sheet 7 can be easily peeled from a base. Further, the adhesive residue on the pedestal can be eliminated, and the pedestal cleaning step can be omitted.

The adhesive strength of the third layer 75 is preferably such that the 90 ° peel peel force for a silicon wafer under the conditions of a temperature of 23 ± 2 ° C. and a peel rate of 300 mm / min is less than 0.30 N / 20 mm. More preferably, it is 20 N / 20 mm or less. The adhesive sheet 7 can be peeled easily as it is less than 0.30 N / 20 mm. Further, the adhesive residue on the pedestal and the like can be eliminated, and the cleaning process for the pedestal and the like can be omitted. On the other hand, the lower limit of the 90 ° peel peel force is preferably 0.001 N / 20 mm or more. When it is 0.001 N / 20 mm or more, the semiconductor wafer can be fixed to the pedestal well, and back grinding and the like can be performed well.

The adhesive composition constituting the first adhesive layer 70 is not particularly limited as long as it is selected so that the adhesive force of the first adhesive layer 70 is higher than the adhesive force of the second layer 71.

As an adhesive composition constituting the first adhesive layer 70, a polyimide resin having an imide group and having a structural unit derived from a diamine having an ether structure at least partially can be used. Moreover, a silicone resin can also be used suitably. Especially, the said polyimide resin is preferable from the point of heat resistance, chemical resistance, and adhesive residue.

The polyimide resin can be generally obtained by imidizing (dehydrating and condensing) a polyamic acid that is a precursor thereof. As a method for imidizing the polyamic acid, for example, a conventionally known heat imidization method, azeotropic dehydration method, chemical imidization method and the like can be employed. Of these, the heating imidization method is preferable. When the heat imidization method is employed, it is preferable to perform heat treatment under a nitrogen atmosphere or an inert atmosphere such as a vacuum in order to prevent deterioration of the polyimide resin due to oxidation.

The polyamic acid is charged in an appropriately selected solvent such that an acid anhydride and a diamine (including both a diamine having an ether structure and a diamine not having an ether structure) have a substantially equimolar ratio. Can be obtained by reaction.

The diamine having an ether structure is not particularly limited as long as it is a compound having an ether structure and having at least two terminals having an amine structure. Examples thereof include diamine having a glycol skeleton.

Examples of the diamine having a glycol skeleton include a polypropylene glycol structure and a diamine having one amino group at each end, a polyethylene glycol structure, and one amino group at each end. Examples thereof include a diamine having a polytetramethylene glycol structure and a diamine having an alkylene glycol such as a diamine having one amino group at each end. Moreover, the diamine which has two or more of these glycol structures and has one amino group in both the ends can be mentioned.

The molecular weight of the diamine having an ether structure is preferably in the range of 100 to 5000, and more preferably 150 to 4800. When the molecular weight of the diamine having an ether structure is in the range of 100 to 5000, it is easy to obtain the first adhesive layer 70 having high adhesive strength at low temperatures and exhibiting peelability at high temperatures.

In the formation of the polyimide resin, a diamine having no ether structure can be used in combination with a diamine having an ether structure. Examples of the diamine having no ether structure include aliphatic diamines and aromatic diamines. By using a diamine having no ether structure in combination, the adhesion with the adherend can be controlled. The mixing ratio of the diamine having an ether structure and the diamine having no ether structure is preferably in the range of 100: 0 to 10:90, more preferably 100: 0 to 20: in terms of molar ratio. 80, more preferably 99: 1 to 30:70. When the mixing ratio of the diamine having an ether structure and the diamine having no ether structure is within a range of 100: 0 to 10:90 in terms of molar ratio, the thermal peelability at a high temperature is excellent.

Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, 1,8-diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane, 4,9-dioxa-1,12-diaminododecane, , 3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane (α, ω-bisaminopropyltetramethyldisiloxane) and the like. The molecular weight of the aliphatic diamine is usually 50 to 1,000,000, preferably 100 to 30,000.

Examples of the aromatic diamine include 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, and 4,4′-diaminodiphenylpropane. 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) -2,2- Dimethylpropane, 4,4'-diaminobenzophenone, etc. It is. The molecular weight of the aromatic diamine is usually 50 to 1000, preferably 100 to 500. The molecular weight of the aliphatic diamine and the molecular weight of the aromatic diamine are values measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene (weight average molecular weight).

Examples of the acid anhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 2,2-bis (2, 3-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), bis (2,3-dicarboxyphenyl) methane dianhydride Bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydride, pyromellitic dianhydride, ethylene glycol bis trimellitic dianhydride and the like. These may be used alone or in combination of two or more.

Examples of the solvent for reacting the acid anhydride with the diamine include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, and cyclopentanone. These may be used alone or in combination. Further, in order to adjust the solubility of raw materials and resins, a nonpolar solvent such as toluene or xylene may be appropriately mixed and used.

Examples of the silicone resin include peroxide cross-linked silicone pressure-sensitive adhesives, addition reaction type silicone pressure-sensitive adhesives, dehydrogenation reaction type silicone pressure-sensitive adhesives, and moisture-curing type silicone pressure-sensitive adhesives. The said silicone resin may be used individually by 1 type, and may use 2 or more types together. When the silicone resin is used, the heat resistance becomes high, and the storage elastic modulus and adhesive strength at high temperatures can be appropriate values. Among the silicone resins, addition reaction type silicone pressure-sensitive adhesives are preferable in terms of few impurities.

The adhesive composition constituting the first adhesive layer 70 may contain other additives. Examples of such other additives include flame retardants, silane coupling agents, and ion trapping agents. Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resin. Examples of the silane coupling agent include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like. Examples of the ion trapping agent include hydrotalcites and bismuth hydroxide. Such other additives may be only one kind or two or more kinds.

The material constituting the second layer 71 is not particularly limited as long as it is selected so that the adhesive force of the second layer 71 is lower than the adhesive force of the first adhesive layer 70. As a material constituting the second layer 71, the aforementioned polyimide resin and the aforementioned silicone resin can also be used. Especially, the said polyimide resin is preferable from the point of heat resistance, chemical resistance, and adhesive residue.

The material constituting the third layer 75 is not particularly limited as long as the material is selected so that the adhesive force of the third layer 75 is lower than the adhesive force of the first adhesive layer 70. What was illustrated by the layer 71 of this is mentioned.

(Manufacture of adhesive sheets)
The adhesive sheet 7 is produced as follows, for example. First, a solution containing a material for forming the second layer 71 is prepared. Next, the solution is applied on a substrate so as to have a predetermined thickness to form a coating film, and then the coating film is dried under predetermined conditions to form the second layer 71. Examples of the base material include metal foil such as SUS304, 6-4 alloy, aluminum foil, copper foil, Ni foil, polyethylene terephthalate (PET), polyethylene, polypropylene, fluorine-based release agent, and long-chain alkyl acrylate release agent. A plastic film, paper, or the like whose surface is coated with a release agent such as, can be used. Moreover, it does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, spin coat coating etc. are mentioned.

On the other hand, a solution containing a composition for forming the first adhesive layer 70 is prepared.

Next, a solution containing a composition for forming the first adhesive layer 70 is formed on the base material on which the second layer 71 is laminated to a predetermined thickness from the second layer 71 side. In this way, a coating film is formed. Thereafter, the coating film is dried under predetermined conditions to form the first adhesive layer 70. From the above, the adhesive sheet 7 shown in FIG. 1 is obtained.

Note that the third layer 75 illustrated in FIG. 2 can be formed by a method similar to that of the second layer 71.

The adhesive sheet for manufacturing a semiconductor device according to the first aspect of the present invention is used for fixing a semiconductor wafer to a pedestal. Specifically, it can be suitably used in the method for manufacturing a semiconductor device according to the first aspect of the present invention described later.

[Method for Manufacturing Semiconductor Device]
The manufacturing method of the semiconductor device of 1st this invention includes the process of fixing a semiconductor wafer to a base using an adhesive sheet, and the process of isolate | separating a base from a semiconductor wafer. As such a method, for example, the step of fixing the semiconductor wafer to the pedestal by attaching the semiconductor wafer to the first adhesive layer and attaching the pedestal to the second layer, and the step of separating the pedestal from the semiconductor wafer The method containing these is mentioned. In the case of the method, the first adhesive layer can follow the irregularities on the surface of the semiconductor wafer, and the semiconductor wafer can be fixed to the pedestal satisfactorily. On the other hand, since the 2nd layer whose adhesive force is lower than a 1st adhesive bond layer contacts a base, it is easy to peel an adhesive sheet from a base. In addition, there is little adhesive residue on the pedestal and it is easy to reuse the pedestal.

In the following description, the case where the adhesive sheet 7 of Embodiment 1 is used will be described. FIG. 3 is a schematic diagram illustrating a state in which a semiconductor wafer is attached to the adhesive sheet of the first embodiment. FIG. 4 is a schematic diagram illustrating a state in which the semiconductor wafer is fixed to the pedestal using the adhesive sheet of the first embodiment.

First, the circuit formation surface of the semiconductor wafer 3 and the first adhesive layer 70 are bonded together (FIG. 3).

A semiconductor wafer 3 having a circuit forming surface and a non-circuit forming surface is used. Moreover, what has a silicon penetration electrode (through-silicon via) can be used conveniently. This is because a silicon wafer having through silicon vias is usually thinned by back grinding, which will be described later, so that it is desirable to fix the silicon wafer to the pedestal 1 and reinforce the strength.

The semiconductor wafer 3 is not particularly limited, and examples thereof include a germanium wafer, a gallium-arsenic wafer, a gallium-phosphorus wafer, a gallium-arsenic-aluminum wafer, and a compound semiconductor wafer such as a sapphire wafer. Among these, a silicon wafer is preferable.

Although the thickness of the semiconductor wafer 3 is not specifically limited, For example, it is 400-1200 micrometers, Preferably it is 450-1000 micrometers.

Although the diameter of the semiconductor wafer 3 is not specifically limited, For example, it is 75-450 mm. As such a semiconductor wafer 3, a commercially available 200 mm wafer, 300 mm wafer, or the like can be used.

The bonding method (the bonding method) is not particularly limited, and examples thereof include a method of bonding at 23 to 250 ° C. and 0.01 to 10 MPa.
In addition, what is necessary is just to cut the adhesive sheet 7 before bonding or after bonding as needed, when the area of the adhesive sheet 7 is larger than the area of the semiconductor wafer 3.

Next, the base 1 and the second layer 71 are bonded together (FIG. 4).

The pedestal 1 is not particularly limited, and examples thereof include compound wafers such as silicon wafers, SiC wafers, and GaAs wafers, glass wafers, metal foils such as SUS, 6-4 Alloy, Ni foil, and Al foil. In the case of adopting a round shape in plan view, a silicon wafer or a glass wafer is preferable. Moreover, when it is a rectangle by planar view, a SUS board or a glass plate is preferable.

Moreover, as the base 1, for example, low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, polymethylpentene, etc. Polyolefin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene -Hexene copolymers, polyesters such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamide Polyphenyl sulphates id, aramid (paper), can be glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, also possible to use paper or the like.

The pedestal 1 may be used alone or in combination of two or more. Although the thickness of the base 1 is not specifically limited, For example, it is about 10 micrometers-about 20 mm normally.

Although the diameter of the base 1 is not specifically limited, For example, they are 75-450 mm and 100-450 mm. As such a pedestal 1, a commercially available 200 mm wafer, 300 mm wafer, or the like can be used.

The bonding method (the bonding method) is not particularly limited, and examples thereof include a method of bonding at 23 to 250 ° C. and 0.01 to 10 MPa.
In addition, what is necessary is just to cut the adhesive sheet 7 as needed, when the area of the adhesive sheet 7 is larger than the area of the base 1. FIG.

After bonding, the first adhesive layer 70 and the second layer 71 are imidized as necessary. Thereby, the semiconductor wafer 3 can be favorably fixed to the base 1. Imidization can be performed by a conventionally known method, for example, it can be imidized under conditions of 150 to 500 ° C. and 0.5 to 5 hours. Only one of the first adhesive layer 70 and the second layer 71 may be imidized.

In addition, after bonding, the first adhesive layer 70 and the second layer 71 may be thermoset as necessary. When a silicone resin is used as the first adhesive layer 70 and the second layer 71, the semiconductor wafer 3 can be satisfactorily fixed to the base 1 by thermosetting. Only one of the first adhesive layer 70 and the second layer 71 may be thermally cured.

Subsequently, the semiconductor wafer 3 fixed to the base 1 can be back-ground. The back grinding can be performed by a conventionally known method.

The thickness of the back-ground semiconductor wafer is, for example, 1 to 300 μm, and preferably 5 to 100 μm.

After the back grinding, the non-circuit forming surface (the back ground surface) of the semiconductor wafer 3 can be processed. Examples of processing methods include electrode formation, metal wiring formation, and protective film formation. Note that a through silicon via may be formed by the processing.

After performing desired processing such as back grinding and processing on the semiconductor wafer 3, the pedestal 1 is separated from the semiconductor wafer 3.

The method for separating the pedestal 1 from the semiconductor wafer 3 is not particularly limited, and examples thereof include a method of applying an external force. Specifically, a method of separating only the pedestal 1, a method of separating the second layer 71 with the pedestal 1, and the like can be given. In addition, a method of cutting and separating the boundary between the first adhesive layer 70 and the second layer 71 is also suitable.

Note that the base 1 may be separated from the semiconductor wafer 3 after the adhesive force of the first adhesive layer 70 is reduced. As a method of reducing the adhesive force of the first adhesive layer 70, a method of lowering the adhesive force by dissolving the first adhesive layer 70 with a solvent, the first adhesive layer 70 is physically applied with a cutter or a laser. The first adhesive layer 70 is made of a material whose adhesive strength is reduced by heating, and the adhesive strength is reduced by heating, and heating in the presence of a surfactant. A method of performing ultrasonic cleaning, a method of penetrating a chemical solution into the first adhesive layer 70 (for example, a method of performing SC-1 cleaning, a method of penetrating a solution such as N-methyl-2-pyrrolidone), etc. Can be mentioned.

In the above description, the method of attaching the semiconductor wafer 3 to the first adhesive layer 70 and attaching the pedestal 1 to the second layer 71 has been described. However, the present invention is not limited to this, and the base 1 may be attached to the first adhesive layer 70 and the semiconductor wafer 3 may be attached to the second layer 71.

Further, the case where the semiconductor wafer 3 having a circuit forming surface and a non-circuit forming surface is used has been described. However, the present invention is not limited to those having a circuit forming surface and a non-circuit forming surface, and both surfaces may be non-circuit forming surfaces.

[Manufacturing method of other semiconductor device]
The manufacturing method of the semiconductor device of the second aspect of the present invention includes a step (A) of attaching a semiconductor wafer to the adhesive sheet (a), a step (B) of attaching a base to the adhesive sheet (b), and the step (A Step of bonding the adhesive sheet (a) of the semiconductor wafer with the adhesive sheet (a) obtained by the step (b) and the adhesive sheet (b) of the base with the adhesive sheet (b) obtained by the step (B) ( C). Moreover, one adhesive force of the said adhesive sheet (a) and (b) is lower than the other.

Since one adhesive force of the adhesive sheets (a) and (b) is lower than the other, the pedestal is easily separated from the semiconductor wafer. In addition, since the adhesive sheet having a relatively high adhesive force is used, the semiconductor wafer can be satisfactorily fixed to the pedestal.

It is preferable that the adhesive strength of the adhesive sheet (b) is lower than that of the adhesive sheet (a). In this case, the adhesive sheet (a) has a higher adhesive force than the adhesive sheet (b), and is excellent in irregularity followability on the surface of the semiconductor wafer and the like. Therefore, since the adhesive sheet (a) can follow the irregularities on the surface of the semiconductor wafer, the semiconductor wafer can be satisfactorily fixed to the pedestal. On the other hand, since the adhesive sheet (b) having an adhesive force lower than that of the adhesive sheet (a) is in contact with the pedestal, the adhesive sheet (b) is easily peeled from the pedestal. In addition, there is little adhesive residue on the pedestal and it is easy to reuse the pedestal.

In the following description, a case where the adhesive strength of the adhesive sheet (b) is lower than that of the adhesive sheet (a) will be described.

A method for manufacturing a semiconductor device according to the second aspect of the present invention will be described below with reference to the drawings.
FIG. 5 is a schematic cross-sectional view of the adhesive sheet (a). FIG. 6 is a schematic view showing a state in which a semiconductor wafer is attached to the adhesive sheet (a). FIG. 7 is a schematic cross-sectional view of the adhesive sheet (b). FIG. 8 is a schematic diagram showing a state in which a pedestal is attached to the adhesive sheet (b). FIG. 9 is a schematic view showing a state in which the semiconductor wafer is fixed to the pedestal using the adhesive sheets (a) and (b).

Step (A)
In the step (A), the semiconductor wafer 4 is attached to the adhesive sheet (a) 13 (FIG. 6).

First, the adhesive sheet (a) 13 will be described. As shown in FIG. 5, the adhesive sheet (a) 13 has a substrate 12 on one side and a separator 14 on the other side.

Although it does not specifically limit as an adhesive composition which comprises the adhesive sheet (a) 13, What was illustrated by the 1st adhesive bond layer 70 is suitable.

The adhesive strength of the adhesive sheet (a) 13 is preferably, for example, a 90 ° peel peel force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel speed of 300 mm / min is 0.30 N / 20 mm or more. 0.40 N / 20 mm or more is more preferable. When it is 0.30 N / 20 mm or more, the semiconductor wafer 4 can be fixed to the pedestal satisfactorily, and back grinding and the like can be performed satisfactorily. The upper limit of the 90 ° peel peel force is not particularly limited and is preferably as large as possible. For example, it is 30 N / 20 mm or less, preferably 20 N / 20 mm or less.

As the substrate 12, metal foil such as SUS304, 6-4 alloy, aluminum foil, copper foil, Ni foil, polyethylene terephthalate (PET), polyethylene, polypropylene, fluorine release agent, long chain alkyl acrylate release agent Examples thereof include a plastic film or paper whose surface is coated with a release agent such as

Examples of the separator 14 include plastic film and paper whose surface is coated with a release agent such as polyethylene terephthalate (PET), polyethylene, polypropylene, a fluorine release agent, and a long-chain alkyl acrylate release agent.

The semiconductor wafer 4 is not particularly limited, and examples include those exemplified for the semiconductor wafer 3.

In step A, the separator 14 is peeled off, and the semiconductor wafer 4 is attached to the adhesive sheet (a) 13.

The attaching method is not particularly limited, and examples thereof include a method of attaching at 23 to 250 ° C. and 0.01 to 10 MPa.
In addition, when the area of the adhesive sheet (a) 13 is larger than the area of the semiconductor wafer 4, the adhesive sheet (a) 13 may be cut as necessary before or after the attachment.

Process (B)
At a process (B), the base 2 is affixed on the adhesive sheet (b) 23 (FIG. 8).

As shown in FIG. 7, the adhesive sheet (b) 23 has a base material 22 on one surface and a separator 24 on the other surface.

Although it does not specifically limit as an adhesive composition which comprises the adhesive sheet (b) 23, What was illustrated by the 2nd layer 71 is suitable.

The adhesive strength of the adhesive sheet (b) 23 is preferably, for example, a 90 ° peel peeling force to a silicon wafer under a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min is less than 0.30 N / 20 mm, More preferably, it is 0.20 N / 20 mm or less. If it is less than 0.30 N / 20 mm, the base 2 can be easily separated from the semiconductor wafer 4. On the other hand, the lower limit of the 90 ° peel strength is preferably 0.001 N / 20 mm or more, more preferably 0.005 N / 20 mm or more, and still more preferably 0.010 N / 20 mm or more. When it is 0.001 N / 20 mm or more, the semiconductor wafer 4 can be fixed to the pedestal 2 satisfactorily and back grinding can be performed satisfactorily.

It does not specifically limit as the base material 22, What was illustrated by the base material 12 etc. are mentioned. It does not specifically limit as the separator 24, What was illustrated by the separator 14 etc. are mentioned.

The pedestal 2 is not particularly limited, and examples thereof include those exemplified for the pedestal 1.

In step B, the separator 24 is peeled off, and the base 2 is attached to the adhesive sheet (b) 23.

The attaching method is not particularly limited, and examples thereof include a method of attaching at 23 to 250 ° C. and 0.01 to 10 MPa.
When the area of the adhesive sheet (b) 23 is larger than the area of the pedestal 2, the adhesive sheet (b) 23 may be cut before or after application as necessary.

Process (C)
In the step (C), the adhesive sheet (a) 13 of the semiconductor wafer 4 with the adhesive sheet (a) 13 obtained in the step (A) and the base 2 with the adhesive sheet (b) 23 obtained in the step (B). The adhesive sheet (b) 23 is bonded together (FIG. 9). Thereby, the semiconductor wafer 4 can be fixed to the base 2.

The bonding method is not particularly limited. After bonding, the adhesive sheet (a) 13 and the adhesive sheet (b) 23 are imidized as necessary. Thereby, the semiconductor wafer 4 can be favorably fixed to the base 2. Imidization can be performed by a conventionally known method, for example, it can be imidized under conditions of 150 to 500 ° C. and 0.5 to 5 hours. Only one of the adhesive sheet (a) 13 and the adhesive sheet (b) 23 may be imidized.

Moreover, after bonding, the adhesive sheet (a) 13 and the adhesive sheet (b) 23 may be thermoset as necessary. When a silicone resin is used as the adhesive sheet (a) 13 and the adhesive sheet (b) 23, the semiconductor wafer 4 can be satisfactorily fixed to the base 2 by thermosetting. Only one of the adhesive sheet (a) 13 and the adhesive sheet (b) 23 may be thermally cured.

The semiconductor wafer 4 fixed to the other process base 2 can be back-ground. The back grinding can be performed by a conventionally known method.

The thickness of the back-ground semiconductor wafer is, for example, 1 to 300 μm, and preferably 5 to 100 μm.

After the back grinding, the non-circuit forming surface (the back ground surface) of the semiconductor wafer 4 can be processed. Examples of processing methods include electrode formation, metal wiring formation, and protective film formation. Note that a through silicon via may be formed by the processing.

After a desired process such as back grinding or processing is performed on the semiconductor wafer 4, the pedestal 2 is separated from the semiconductor wafer 4.

The method for separating the pedestal 2 from the semiconductor wafer 4 is not particularly limited, and examples thereof include the method exemplified in the description of the method for separating the pedestal 1 from the semiconductor wafer 3.

In the above description, the case where the adhesive strength of the adhesive sheet (b) 23 is lower than that of the adhesive sheet (a) 13 has been described. However, the present invention is not limited to this, and the adhesive strength of the adhesive sheet (b) 23 may be higher than that of the adhesive sheet (a) 13.

In this case, the adhesive force of the adhesive sheet (b) 23 is, for example, a 90 ° peel peel force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel speed of 300 mm / min is 0.30 N / 20 mm or more. It is preferable that it is 0.40 N / 20 mm or more. The upper limit of the 90 ° peel peel force is, for example, 30 N / 20 mm or less, preferably 20 N / 20 mm or less.
Moreover, the adhesive strength of the adhesive sheet (a) 13 is, for example, that the 90 ° peel peeling force for a silicon wafer under the conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min is less than 0.30 N / 20 mm. Preferably, it is 0.20 N / 20 mm or less. The lower limit of the 90 ° peel strength is preferably 0.001 N / 20 mm or more, more preferably 0.005 N / 20 mm or more, and further preferably 0.010 N / 20 mm or more.

Moreover, in the above description, the case where the adhesive sheet (a) 13 has the base material 12 and the separator 14 was demonstrated. However, the present invention is not limited to this, and the adhesive sheet (a) 13 may not have the separator 14 and may not have the substrate 12. The adhesive sheet (b) 23 is the same, and the adhesive sheet (b) 23 may not have the separator 24 and may not have the base material 22.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

The components used in the examples will be described.
PMDA: pyromellitic dianhydride (molecular weight: 218.1)
DDE: 4,4′-diaminodiphenyl ether (molecular weight: 200.2)
D-4000: Heinzmann polyether diamine (molecular weight: 4023.5)
DMAc: N, N-dimethylacetamide D-2000: Heinzmann polyether diamine (molecular weight: 1990.8)
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride PPD: p-phenylenediamine separator (long polyester film treated on one side with a silicone-based release agent: thickness 38 μm)

An adhesive sheet was produced by the following method.

Example 1
In an atmosphere under a nitrogen stream, D-4000 239.8 g, DDE 79.9 g and PMDA 100.0 g were mixed and reacted at 1912.0 g of DMAc at 70 ° C. to obtain a first adhesive layer solution. (Polyamic acid solution A) was obtained. The resulting first adhesive layer solution was cooled to room temperature (23 ° C.).
A second layer solution (polyamic acid solution B) was obtained in the same manner as the first adhesive layer solution except that the formulation in Table 1 was followed. The resulting second layer solution was cooled to room temperature (23 ° C.).
The second layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having the second layer. On the obtained sheet, the first adhesive layer solution was applied and dried at 90 ° C. for 3 minutes to form a first adhesive layer. As a result, an adhesive sheet in which the first adhesive layer and the second layer were laminated was obtained.
The entire diameter of the adhesive sheet was 200 mm, and the thickness was 100 μm.
The diameter of the first adhesive layer was 200 mm, and the thickness was 90 μm.
The diameter of the second layer was 200 mm and the thickness was 10 μm.

Examples 2-3
An adhesive sheet was obtained in the same manner as in Example 1 except that the composition according to Table 1 was followed.

Comparative Example 1
Using the first adhesive layer solution of Example 1, an adhesive sheet (single layer) composed of the first adhesive layer was obtained. The adhesive sheet was circular and had a diameter of 200 mm and a thickness of 150 μm.

[Measurement of adhesive strength of first adhesive layer]
The first adhesive layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a first adhesive layer having a thickness of 20 μm.
The first adhesive layer of the obtained sheet was bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to obtain a first adhesive layer with a silicon wafer.
The first adhesive layer with a silicon wafer was processed to a width of 20 mm and a length of 100 mm, and a 90 ° peel evaluation was performed at a temperature of 23 ° C. and 300 mm / min using a tensile tester (manufactured by Shimadzu Corporation, Autograph AGS-H). went. The results are shown in Table 1.

[Measurement of adhesive strength of second layer]
The second layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a second layer having a thickness of 20 μm.
The second layer of the obtained sheet was bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to obtain a second layer with a silicon wafer.
A second layer with a silicon wafer is processed to a width of 20 mm and a length of 100 mm, and a 90 ° peel evaluation is performed at a temperature of 23 ° C. and 300 mm / min using a tensile tester (manufactured by Shimadzu Corp., Autograph AGS-H). It was. The results are shown in Table 1.

[Process resistance evaluation]
Examples 1-3
The 2nd layer of the adhesive sheet of Examples 1-3 was affixed on the base (diameter 200mm, thickness 726 micrometers silicon wafer). The pasting was performed by roll lamination at a temperature of 90 ° C. and a pressure of 0.1 MPa.
Next, the adhesive sheet surface of the adhesive sheet with a pedestal was attached to the circuit forming surface of a silicon wafer having a diameter of 200 mm and a thickness of 725 μm. The pasting was performed by roll lamination at a temperature of 90 ° C. and a pressure of 0.1 MPa. After pasting, the adhesive sheet was imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours. As a result, a laminated body in which the pedestal, the adhesive sheet, and the silicon wafer were sequentially laminated was obtained.
Backgrinding was performed using the obtained laminate, and the case where the silicon wafer could be sufficiently fixed in the backgrind and satisfactorily background could be obtained. As evaluated.
Comparative Example 1
A laminate was obtained by the same method as in Examples 1 to 3, and the process resistance was evaluated.
The results are shown in Table 1.

[Peelability evaluation]
A laminated body in which a pedestal, an adhesive sheet, and a silicon wafer were sequentially laminated was obtained by the same method as in the process resistance evaluation.
A cut was made at the boundary between the first adhesive layer and the second layer using a Thomson blade (1 mm cut from the edge of the silicon wafer). After cutting, the silicon wafer was adsorbed upward using vacuum tweezers arranged on the silicon wafer side of the laminate. The case where the first adhesive layer with a silicon wafer was peeled from the laminate by adsorption was evaluated as ◯, and the case where the first adhesive layer could not be peeled was evaluated as x. The results are shown in Table 1.

1 pedestal 2 pedestal 3 semiconductor wafer 4 semiconductor wafer 7 adhesive sheet 12 base material 13 adhesive sheet 14 separator 22 base material 23 adhesive sheet 24 separator 70 first adhesive layer 71 second layer 75 third layer

Claims (5)

An adhesive sheet for manufacturing a semiconductor device used for fixing a semiconductor wafer to a pedestal,
An adhesive sheet for manufacturing a semiconductor device, wherein a first adhesive layer and a second layer having lower adhesive strength than the first adhesive layer are laminated. Fixing the semiconductor wafer to the pedestal using the adhesive sheet for manufacturing a semiconductor device according to claim 1;
And a step of separating the pedestal from the semiconductor wafer. The step of fixing the semiconductor wafer to the pedestal using the adhesive sheet for manufacturing a semiconductor device includes attaching the semiconductor wafer to the first adhesive layer and attaching the pedestal to the second layer. The method of manufacturing a semiconductor device according to claim 2, wherein the semiconductor wafer is a step of fixing the semiconductor wafer to the pedestal. A step (A) of attaching a semiconductor wafer to the adhesive sheet (a);
A step (B) of attaching a pedestal to the adhesive sheet (b);
The adhesive sheet (a) of the semiconductor wafer with the adhesive sheet (a) obtained by the step (A) and the adhesive sheet (b) of the base with the adhesive sheet (b) obtained by the step (B). Including the step of bonding (C),
A method for manufacturing a semiconductor device, wherein one of the adhesive sheets (a) and (b) has a lower adhesive strength than the other. The method for manufacturing a semiconductor device according to claim 4, wherein an adhesive force of the adhesive sheet (b) is lower than that of the adhesive sheet (a).

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