JP2014088523A - 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 capable of satisfactorily fixing a semiconductor wafer to a pedestal and further capable of easily separating the pedestal from the semiconductor wafer.SOLUTION: Provided is an adhesive sheet for manufacturing a semiconductor used for fixing a semiconductor wafer to a pedestal. The adhesive sheet comprises a first adhesive layer and a second layer with a structure having many through holes and/or a nonwoven fabric-shaped structure as a skeleton, and the adhesive force of the second layer is lower than the adhesive force of the first adhesive layer.

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 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 can easily separate the pedestal from the semiconductor wafer. Moreover, it aims at providing the manufacturing method of the semiconductor device using this adhesive sheet for semiconductor device manufacture.

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

The present invention is an adhesive sheet for manufacturing a semiconductor device used for fixing a semiconductor wafer to a pedestal, and includes a first adhesive layer, a structure having a large number of through holes, and / or a non-woven structure. The adhesive layer has a second layer, and the adhesive strength of the second layer is lower than the adhesive strength of the first adhesive layer.

Since the adhesive sheet has a sheet shape, the material is not wasted unlike spin coating. In addition, it is not necessary to remove the dirt on the spin coater, and the apparatus maintenance is easy. Since the adhesive sheet is in the form of a sheet, the surface of the first adhesive layer can be formed more uniformly than when the adhesive layer is formed by spin coating, and the adhesive force of the first adhesive layer can be improved.

Since the said adhesive sheet has a 1st adhesive bond layer, a semiconductor wafer can be favorably fixed to a base. On the other hand, 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.

The second layer is a layer having a structure having a large number of through holes and / or a non-woven structure as a skeleton, and can be formed of a mesh such as a wire mesh, a non-woven fabric, or the like. For this reason, what is necessary is just to prepare the adhesive composition of a 1st adhesive bond layer as an adhesive material in manufacture of an adhesive sheet, and it is not necessary to prepare two types of adhesives, a filling layer and an edge bond like patent document 1. .

In the present invention, the adhesive strength of the first adhesive layer and the adhesive strength of the second layer refer to 90 ° peel peel force on a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel rate of 300 mm / min. . In addition, when a 1st adhesive bond layer is what adhere | attaches by performing imidation, thermosetting, etc., the 90 degree peel peel force in the state (for example, after imidation or after thermosetting) fixed to the silicon wafer. Say. The same applies to the second layer. Specifically, it can be measured by the method described in the examples.

It is preferable that the through holes and the pores of the nonwoven fabric-like structure are filled with an adhesive composition. In this case, the area where the adhesive composition comes into contact with the semiconductor wafer or the pedestal can be controlled by the aperture ratio of the structure having through holes, the density of the non-woven structure, etc. Can be formed.

It is preferable that at least a peripheral portion of the adhesive sheet for manufacturing a semiconductor device is formed by the first adhesive layer.
Since the peripheral part of the said adhesive sheet is formed of the 1st adhesive bond layer, it can fix favorably in this part.

It is preferable that a central portion inside the peripheral portion is formed by stacking the first adhesive layer and the second layer. According to the said structure, a semiconductor wafer or a base can be firmly fixed by the surface which consists only of a 1st adhesive bond layer. The semiconductor wafer or the pedestal can be satisfactorily fixed on the surface having the first adhesive layer and the second layer.
Further, since the first adhesive layer is formed in the peripheral portion of the adhesive sheet, it is easy to cut the first adhesive layer or to reduce the adhesive force of the first adhesive layer, and to be easily separated. Can be done.

In the adhesive sheet, it is also preferable that a central portion inside the peripheral portion is formed by the second layer. According to the said structure, a semiconductor wafer or a base can be favorably fixed by the surface which has a 1st adhesive bond layer and a 2nd layer. Further, since the first adhesive layer is formed in the peripheral portion of the adhesive sheet, it is easy to cut the first adhesive layer or to reduce the adhesive force of the first adhesive layer, and to be easily separated. Can be done.

The adhesive sheet is preferably formed by stacking the first adhesive layer and the second layer.

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.

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 cross-sectional view of the adhesive sheet of Embodiment 1. FIG. 2 is a plan view of the adhesive sheet of Embodiment 1. FIG. It is a top view of the structure which has many through-holes. It is sectional drawing of an adhesive sheet provided with a 3rd layer. It is sectional drawing of the adhesive sheet of Embodiment 2. FIG. It is a top view of the adhesive sheet of Embodiment 2. It is sectional drawing of the adhesive sheet of Embodiment 3. 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.

[Adhesive sheet]
The adhesive sheet for manufacturing a semiconductor device according to the present invention includes a first adhesive layer and a second layer having a structure having a large number of through holes and / or a non-woven structure as a skeleton. The adhesive strength of this layer is lower than the adhesive strength of the first adhesive layer.

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

[Embodiment 1]
FIG. 1 is a cross-sectional view of the adhesive sheet 5 of the first embodiment. As shown in FIG. 1, the adhesive sheet 5 has a peripheral portion 54 formed by the first adhesive layer 50, and a central portion 53 inside the peripheral portion 54 has a large number of penetrations through the first adhesive layer 50. It is formed by lamination with a second layer 51 having a structure having holes and / or a non-woven structure as a skeleton. That is, the adhesive sheet 5 includes a second layer 51 and a first adhesive layer 50 that is laminated on the second layer 51 in such a manner as to cover the upper surface and side surfaces of the second layer 51. The adhesive force of the second layer 51 is lower than the adhesive force of the first adhesive layer 50.

The semiconductor wafer or the pedestal can be firmly fixed on the surface composed of only the first adhesive layer 50. The semiconductor wafer or the pedestal can be satisfactorily fixed on the surface having the first adhesive layer 50 and the second layer 51.

Since the adhesive sheet 5 has the second layer 51 having a low adhesive force, for example, the base is easily separated from the semiconductor wafer by an external force by cutting the first adhesive layer 50 or reducing the adhesive force. it can. Since the first adhesive layer 50 is formed in the peripheral portion 54, the adhesive sheet 5 is easy to cut the first adhesive layer 50 or reduce the adhesive force of the first adhesive layer 50, and is separated. Can be easily performed.

The thickness of the adhesive sheet 5 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 can be filled without a gap. Moreover, the thickness of the adhesive sheet 5 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.

Although the thickness of the 1st adhesive bond layer 50 in the center part 53 can be set suitably, Preferably it is 0.1 micrometer or more, More preferably, it is 0.5 micrometer or more, More preferably, it is 1 micrometer or more. Moreover, this thickness becomes like this. Preferably it is 300 micrometers or less, More preferably, it is 200 micrometers or less.
Further, the thickness of the second layer 51 in the central portion 53 can be set as appropriate.

FIG. 2 is a plan view of the adhesive sheet 5 of the first embodiment. As shown in FIG. 2, the adhesive sheet 5 has a circular shape when viewed in plan.
The diameter of the adhesive sheet 5 is not particularly limited. For example, the diameter of the adhesive sheet 5 is preferably +1.0 to −1.0 mm with respect to the diameter of the pedestal.

Further, when the adhesive sheet 5 is viewed in plan, the shape of the second layer 51 is circular. The area of the second layer 51 when the adhesive sheet 5 is viewed in plan is preferably 10% or more, more preferably 20% or more with respect to the area of the adhesive sheet 5 when the adhesive sheet 5 is viewed in plan. Preferably it is 50% or more. If it is 10% or more, it is easy to cut the first adhesive layer 50 formed on the peripheral portion 54 or to reduce the adhesive force, and to easily separate the pedestal from the semiconductor wafer. The area of the second layer 51 is preferably 99.95% or less, more preferably 99.9% or less. A semiconductor wafer can be firmly fixed to a base as it is 99.95% or less.

The adhesive strength of the first adhesive layer 50 is preferably, for example, a 90 ° peel peel force on 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 favorably held on 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.

Although it does not specifically limit as an adhesive composition which comprises the 1st adhesive bond layer 50, The polyimide resin which has an imide group and has a structural unit derived from the diamine which has an ether structure in at least one part is used suitably it can. 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 50 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 50 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 second layer 51 has a structure 57 having a large number of through holes 56 and / or a non-woven structure as a skeleton. FIG. 3 is a plan view of a structure 57 having a large number of through holes 56. As shown in FIG. 3, the through-hole 56 penetrates in the thickness direction of the structure 57 (also referred to as the thickness direction of the adhesive sheet 5).

The adhesive force of the second layer 51 can be adjusted by adjusting the aperture ratio of the structure 57 having a large number of through holes 56. Specifically, when the through hole 56 is filled with an adhesive composition described later, the adhesive force can be increased by increasing the aperture ratio, and the adhesive force can be decreased by decreasing the aperture ratio.
The porosity of the structure 57 is preferably 5% or more, more preferably 8% or more, and further preferably 10% or more. When it is 5% or more, the adhesive composition filled in the through holes 56 can reach the adherend, and the adhesive force of the second layer 51 can be adjusted.
The open area ratio is preferably 98% or less, more preferably 95% or less, and still more preferably 90% or less. When it is 98% or less, the adhesive force of the second layer 51 can be made lower than that of the first adhesive layer 50 even when the same adhesive composition as that of the first adhesive layer 50 is filled in the through holes 56.

In the structure 57, the shape of the through hole 56 (the shape of the through hole 56 when the adhesive sheet 5 is viewed in plan) is not particularly limited, and examples thereof include a circle, an ellipse, and a polygon. The shapes of the through holes 56 may all be the same or different.

When the adhesive sheet 5 is viewed in plan, the size (area) of one through hole 56 is preferably 70 μm ² or more, more preferably 100 μm ² or more. Further, it is preferably 20 mm ² or less, more preferably 7 mm ² or less. The sizes of the through holes 56 may all be the same or different.

The material of the structure 57 having a large number of through-holes 56 and the non-woven fabric structure is not particularly limited. For example, polyolefins such as low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, polymethylpentene, ethylene-acetic acid Vinyl copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, Polyester such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyimide resin, polyetherimide, polyamide, wholly aromatic polyamide, polyphenyls Fuido, aramid (paper), glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, paper and the like. In addition, metal materials such as iron, copper, nickel, tungsten, aluminum, gold, silver, copper, brass, red copper, phosphor bronze, nichrome, monel metal, bronze, and stainless steel (SUS) can be used. These may be used alone or in combination of two or more. Especially, when it is the structure 57 which has many through-holes 56, from a heat resistant point, a metal material, the above-mentioned polyimide resin, and the above-mentioned silicone resin are preferable, and SUS and aluminum are more preferable. In the case of a non-woven structure, the above-described polyimide resin, the above-described silicone resin, and metal material are preferable from the viewpoint of heat resistance and contamination.

The lower the adhesive strength of the structure 57 having a large number of through-holes 56 and the non-woven structure, the more preferable, for example, 90 ° peel peeling with respect to a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min. The force is preferably less than 0.30 N / 20 mm, more preferably 0.20 N / 20 mm or less, and even more preferably 0.10 N / 20 mm or less. If the thickness is less than 0.30 N / 20 mm, the second layer 51 can be easily peeled off. The lower limit of the 90 ° peel peeling force is, for example, 0 N / 20 mm or more and 0.001 N / 20 mm or more.
When the structure 57 having a large number of through holes 56 and the non-woven structure are bonded by imidization or thermosetting, the 90 ° peel peeling force is fixed to the silicon wafer. The 90 ° peel peel force in a state (for example, after imidization or after thermosetting). Specifically, it can be measured by the method described in the examples.

The through-hole 56 and the porosity of the nonwoven fabric-like structure may be filled with the adhesive composition or may not be filled. It is preferable that the second layer having a low adhesive force can be easily formed by controlling the aperture ratio of the structure 57 and the density of the non-woven structure.

It does not specifically limit as an adhesive composition which fills the through-hole 56 or the porosity of a nonwoven fabric, For example, the above-mentioned polyimide resin, the above-mentioned silicone resin, etc. are mentioned.

The adhesive force of the second layer 51 is lower than the adhesive force of the first adhesive layer 50. The adhesive force of the second layer 51 is preferably, for example, a 90 ° peel peel force for a silicon wafer under 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. If the thickness is less than 0.30 N / 20 mm, the second layer 51 can be easily peeled off. The lower limit of the 90 ° peel peel force is preferably as low as possible, but is preferably 0 N / 20 mm or more, more preferably 0.001 N / 20 mm or more, still more preferably 0.01 N / 20 mm or more, and particularly preferably 0.10 N. / 20 mm or more.
The adhesive strength of the second layer 51 is adjusted by the opening ratio of the structure 57, the density of the nonwoven structure, the type of the adhesive composition that fills the through holes 56 and the pores of the nonwoven fabric, the material of the structure 57, and the like. it can.

As shown in FIG. 4, the adhesive sheet 5 may be formed with other layers. FIG. 4 is a cross-sectional view of the adhesive sheet 5 including the third layer 55. In the adhesive sheet 5 of FIG. 4, a third layer 55 is formed across the peripheral portion 54 and the central portion 53. The adhesive force of the third layer 55 is lower than the adhesive force of the first adhesive layer 50.

When the surface which consists only of the 3rd layer 55 is affixed on a semiconductor wafer or a base, the adhesive sheet 5 can be peeled easily. Further, the adhesive residue on the semiconductor wafer or the pedestal can be eliminated, and the cleaning process can be omitted.

The adhesive force of the third layer 55 is not particularly limited as long as it is lower than the adhesive force of the first adhesive layer 50. For example, the 90 ° peel peeling force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min is preferably less than 0.30 N / 20 mm, and preferably 0.20 N / 20 mm or less. More preferred. When the thickness is less than 0.30 N / 20 mm, the adhesive can be peeled without residue, and the semiconductor wafer cleaning process can be omitted. Moreover, the minimum of this 90 degree peeling force is not specifically limited, For example, it is 0 N / 20mm or more, Preferably it is 0.001 N / 20mm or more. A semiconductor wafer can be hold | maintained to a base as it is 0 N / 20mm or more.

The material constituting the third layer 55 is not particularly limited as long as it is selected so that the adhesive force of the third layer 55 is lower than the adhesive force of the first adhesive layer 50. A polyimide resin and the above-mentioned silicone resin can be used suitably. Especially, the said polyimide resin is preferable from the point of heat resistance, chemical resistance, and adhesive residue.

The manufacturing method of the adhesive sheet 5 is not particularly limited. For example, a solution containing a composition for forming the first adhesive layer 50 is applied to the structure 57 having a large number of through-holes 56 and the periphery thereof (region around the structure 57), and the through-holes 56 are applied. And the coating layer is formed on the structure 57 and around the structure 57. In this method, the coating layer formed around the structure 57 becomes the first adhesive layer 50 in the peripheral portion 54.

In addition, when the second layer 51 has a non-woven structure as a skeleton, a solution containing the composition for forming the first adhesive layer 50 is applied to the non-woven structure and the periphery thereof, It can be manufactured by filling the pores of the non-woven structure with the solution and forming a coating layer on and around the structure. In this method, the coating layer formed around the structure becomes the first adhesive layer 50 in the peripheral portion 54.

The viscosity of the solution to be applied can be set as appropriate. What is necessary is just to set the application quantity suitably.

[Embodiment 2]
The adhesive sheet of the present invention is not limited to the shape of the adhesive sheet 5. FIG. 5 is a cross-sectional view of the adhesive sheet 6 of the second embodiment. FIG. 6 is a plan view of the adhesive sheet 6 according to the second embodiment. As shown in FIGS. 5 and 6, the adhesive sheet 6 has a structure in which the peripheral portion 64 is formed by the first adhesive layer 60 and the central portion 63 inside the peripheral portion 64 has a large number of through holes 66. A second layer 61 having a body as a skeleton is formed. The adhesive force of the second layer 61 is lower than the adhesive force of the first adhesive layer 60.

The second layer 61 may have a non-woven structure as a skeleton.

The semiconductor wafer or the pedestal can be satisfactorily fixed on the surface having the first adhesive layer 60 and the second layer 61.

Since the adhesive sheet 6 has the second layer 61 having a low adhesive force, for example, the base is easily separated from the semiconductor wafer by an external force by cutting the first adhesive layer 60 or reducing the adhesive force. it can. Since the first adhesive layer 60 is formed in the peripheral portion 64, the adhesive sheet 6 can be easily cut off or reduced in the adhesive strength of the first adhesive layer 60, and separated. Can be easily performed.

The thickness of the adhesive sheet 6 is not specifically limited, For example, what was illustrated by the adhesive sheet 5 of Embodiment 1 is mentioned.

As shown in FIG. 6, the adhesive sheet 6 has a circular shape when viewed in plan. The diameter of the adhesive sheet 6 is not specifically limited, For example, what was illustrated by the adhesive sheet 5 of Embodiment 1 is mentioned. Moreover, the area of the 2nd layer 61 when the adhesive sheet 6 is planarly viewed is not specifically limited, For example, what was illustrated with the adhesive sheet 5 of Embodiment 1 is mentioned.

Examples of the adhesive force of the first adhesive layer 60 include those exemplified for the first adhesive layer 50.
The description of the first adhesive layer 60 is the same as the content of the first adhesive layer 50.

Examples of the adhesive force of the second layer 61 include those exemplified for the second layer 51.
The description of the second layer 61 is the same as the content of the second layer 51.

The manufacturing method of the adhesive sheet 6 is not particularly limited. For example, a solution including a composition for forming the first adhesive layer 60 is applied to a structure having a large number of through-holes 66 and the periphery thereof (region around the structure), and the through-holes 66 are formed as described above. It can be manufactured by filling with a solution and forming a coating layer around the structure. In this method, the coating layer formed around the structure becomes the first adhesive layer 60 in the peripheral portion 64.

When the second layer 61 has a non-woven structure as a skeleton, a solution containing the composition for forming the first adhesive layer 60 is applied to the non-woven structure and the periphery thereof. It can be produced by filling the pores of the non-woven structure with the solution and forming a coating layer around the structure. In this method, the coating layer formed around the structure becomes the first adhesive layer 60 in the peripheral portion 64.

The viscosity of the solution to be applied can be set as appropriate. What is necessary is just to set the application quantity suitably.

[Embodiment 3]
The adhesive sheet of the present invention is not limited to the shape of the adhesive sheets 5 and 6. FIG. 7 is a cross-sectional view of the adhesive sheet 7 of the third embodiment. As shown in FIG. 7, the adhesive sheet 7 is formed by laminating a first adhesive layer 70 and a second layer 71 having a structure having a large number of through holes and / or a non-woven fabric structure as a skeleton. Has been. 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. For example, a method of cutting and separating the boundary between the first adhesive layer 70 and the second layer 71 may be used.

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.

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

Examples of the adhesive force of the first adhesive layer 70 include those exemplified for the first adhesive layer 50.
The description of the first adhesive layer 70 is the same as the content of the first adhesive layer 50.

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 description of the second layer 71 is the same as the content of the second layer 51.

The manufacturing method of the adhesive sheet 7 is not particularly limited. For example, a solution containing a composition for forming the first adhesive layer 70 is applied to a structure having a large number of through holes, the through holes are filled with the solution, and a coating layer is formed on the structure. Can be manufactured.

When the second layer 71 has a non-woven structure as a skeleton, a non-woven structure is applied to the non-woven structure by applying a solution containing the composition for forming the first adhesive layer 70. It can be manufactured by filling the pores of the structure with the solution and forming a coating layer on the structure.

The viscosity of the solution to be applied can be set as appropriate. What is necessary is just to set the application quantity suitably.

In the above description, the adhesive sheets 5 to 7 having a circular shape in plan view have been described. However, the shape is not particularly limited, and may be another shape such as a polygon or an ellipse.

In addition, the adhesive sheets 5 to 7 in which the shapes of the second layers 51, 61, and 71 are circular when viewed in plan have been described. However, the shape is not particularly limited, and may be another shape such as a polygon or an ellipse.

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

[Method for Manufacturing Semiconductor Device]
The manufacturing method of the semiconductor device of 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.

In the following description, the case where the adhesive sheet 5 of Embodiment 1 is used will be described. FIG. 8 is a schematic diagram illustrating a state in which the semiconductor wafer 3 is fixed to the pedestal 1 using the adhesive sheet 5 of the first embodiment.

First, a process of fixing the semiconductor wafer 3 to the base 1 using the adhesive sheet 5 is performed. Specifically, the surface of the adhesive sheet 5 on which the first adhesive layer 50 and the second layer 51 are exposed is attached to the base 1, and only the first adhesive layer 50 of the adhesive sheet 5 is exposed. The surface is attached to the circuit forming surface of the semiconductor wafer 3.

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.

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.

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 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, it is 100-450 mm. As such a pedestal 1, a commercially available 200 mm wafer, 300 mm wafer, or the like can be used.

The method of attaching (fixing) is not particularly limited, but pressure bonding is preferable. The crimping is usually performed while pressing with a pressing means such as a crimping roll. As conditions for pressure bonding, for example, 20 to 300 ° C., 0.001 to 10 MPa, and 0.001 to 10 mm / sec are preferable. The crimping time is usually 0.1 to 10 minutes.
After the pressure bonding, the first adhesive layer 50 is 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.
In addition to the imidization of the first adhesive layer 50, an adhesive composition filled in the pores of through holes and nonwoven fabrics may be imidized, and a structure having a large number of through holes or a nonwoven structure May be imidized.

Next, the semiconductor wafer 3 is 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 back grinding and processing, the pedestal 1 is separated from the semiconductor wafer 3.

Although the separation method is not particularly limited, a method of cutting and separating the first adhesive layer 50 and a method of separating by reducing the adhesive force of the first adhesive layer 50 are suitable.

The cutting method is not particularly limited, and examples thereof include a method of cutting the first adhesive layer 50 by cutting the first adhesive layer 50 from the side surface of the adhesive sheet 5 inward. The cutting can be performed by a conventionally known method such as a cutter or a laser.
The method for reducing the adhesive strength of the first adhesive layer 50 is not particularly limited, and the first adhesive layer 50 is formed of a method for dissolving the first adhesive layer 50 with a solvent or a material whose adhesive strength is reduced by heating. In addition, a method of reducing the adhesive force by heating, and the like can be mentioned.

In the above description, as a method of fixing the semiconductor wafer 3 to the pedestal 1 using the adhesive sheet 5, the surfaces of the adhesive sheet 5 on which the first adhesive layer 50 and the second layer 51 are exposed are pasted on the pedestal 1. The method of attaching the surface of the adhesive sheet 5 where only the first adhesive layer 50 is exposed to the circuit forming surface of the semiconductor wafer 3 has been described. However, the method of fixing the semiconductor wafer 3 to the pedestal 1 using the adhesive sheet 5 is not particularly limited, and the surface of the adhesive sheet 5 on which only the first adhesive layer 50 is exposed is attached to the pedestal 1 and the adhesive sheet 5 may be a method in which the surface on which the first adhesive layer 50 and the second layer 51 are exposed is attached to the circuit forming surface of the semiconductor wafer 3.

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.

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 NMP: N-methyl-2-pyrrolidone D-2000: polyether diamine manufactured by Heinzmann (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)

Example 1
In an atmosphere under a nitrogen stream, D-4000 365 g, DDE 74 g, and PMDA 100 g were mixed and reacted at 70 ° C. in 1257 g of DMAc, and then cooled to room temperature (23 ° C.). An adhesive solution was obtained.
A second adhesive solution was obtained in the same manner as the first adhesive solution except that the composition according to Table 1 was followed. The second adhesive solution is applied to the separator and dried at 90 ° C. for 3 minutes to produce a sheet having a coating layer of the second adhesive solution. A sheet was obtained. The shape of the through hole when the perforated sheet was viewed in plan was circular, and the area of each through hole when the perforated sheet was viewed in plan was 78.5 μm ² . The diameter of each through hole was 10 μm. The aperture ratio was 50%.
The first adhesive solution was applied to the perforated sheet and its periphery (region around the perforated sheet), the through holes were filled with the first adhesive solution, and an application layer of the first adhesive solution was formed. Then, it was made to dry at 90 degreeC for 3 minute (s), and the adhesive sheet of the shape of Embodiment 1 shown to FIG.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 100 μm.
The diameter of the second layer was 196 mm, and the thickness of the second layer was 1 μm.
The thickness of the 1st adhesive bond layer in the center part of the adhesive sheet was 99 micrometers.

Example 2
A first adhesive solution was obtained in the same manner as in Example 1 except that the composition according to Table 1 was followed.
An adhesive sheet having the shape of Embodiment 1 shown in FIGS. 1 and 2 was obtained in the same manner as in Example 1 except that an aluminum mesh having an aperture ratio of 80% was used instead of the perforated sheet.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 120.5 μm.
The diameter of the second layer was 198 mm, and the thickness of the second layer was 0.5 μm.
The thickness of the 1st adhesive bond layer in the center part of the adhesive sheet was 120 micrometers.

Example 3
The point which obtained the 1st adhesive solution and the 2nd adhesive solution according to the mixing | blending of Table 1, the shape of the through-hole when a perforated sheet is planarly viewed, and the area of each through-hole are 7.0 mm ² The adhesive sheet having the shape of Embodiment 1 shown in FIGS. 1 and 2 was obtained in the same manner as in Example 1, except that the opening ratio was 10%.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 100 μm.
The diameter of the second layer was 197 mm, and the thickness of the second layer was 1 μm.
The thickness of the 1st adhesive bond layer in the center part of the adhesive sheet was 99 micrometers.

Comparative Example 1
A first adhesive solution was obtained in the same manner as in Example 1 except that the composition according to Table 1 was followed.
The first adhesive solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a single-layer adhesive sheet made of the first adhesive. 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 surface consisting only of the first adhesive layer (the first adhesive solution coating layer) of the adhesive sheet was bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to form silicon. An adhesive sheet with a wafer was obtained.
The adhesive sheet with a silicon wafer was processed into a width of 20 mm and a length of 100 mm, and 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). The results are shown in Table 1.

[Measurement of adhesive strength of perforated sheet and aluminum mesh (structure with many through holes)]
Examples 1 and 3
The perforated sheets of Examples 1 and 3 were bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to obtain a perforated sheet with a silicon wafer.
A perforated sheet 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 using a tensile tester (manufactured by Shimadzu Corporation, Autograph AGS-H) at a temperature of 23 ° C. and 300 mm / min. . The results are shown in Table 1.
Example 2
The aluminum mesh was bonded to an 8-inch silicon wafer to obtain an aluminum mesh with a silicon wafer. The obtained aluminum mesh with a silicon wafer was processed into 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]
A second layer (a second layer comprising a perforated sheet or an aluminum mesh and a first adhesive filled in the through holes) is cut out from the adhesive sheet, and the cut second layer is cut into 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 surfaces on which the first adhesive layer and the second layer of the adhesive sheets of Examples 1 to 3 were exposed were attached to a pedestal (a silicon wafer having a diameter of 200 mm and a thickness of 726 μm). 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. Pasting was performed 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.
Using a Thomson blade, a cut was made inward from the side surface of the adhesive sheet layer. The cut was made until the second layer was reached. After cutting, the silicon wafer was adsorbed upward using vacuum tweezers arranged on the upper side (silicon wafer side) of the laminate. The case where it was able to adsorb | suck was evaluated as (circle) and the case where it was not able to adsorb was evaluated as x. The results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Base 3 Semiconductor wafer 5 Adhesive sheet 50 1st adhesive layer 51 2nd layer 53 Center part 54 Peripheral part 55 3rd layer 56 Through-hole 57 Structure which has many through-holes 6 Adhesive sheet 60 1st adhesive Layer 61 Second layer 63 Central part 64 Peripheral part 66 Through-hole 7 Adhesive sheet 70 First adhesive layer 71 Second layer

Claims (7)

An adhesive sheet for manufacturing a semiconductor device used for fixing a semiconductor wafer to a pedestal,
A first adhesive layer, and a second layer having a structure having a large number of through holes and / or a non-woven structure as a skeleton,
The adhesive sheet for manufacturing a semiconductor device, wherein an adhesive force of the second layer is lower than an adhesive force of the first adhesive layer. 2. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the through-holes and the pores of the nonwoven fabric-like structure are filled with an adhesive composition. 3. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein at least a peripheral portion of the adhesive sheet for manufacturing a semiconductor device is formed by the first adhesive layer. 4. The adhesive sheet for manufacturing a semiconductor device according to claim 3, wherein a central portion inside the peripheral portion is formed by stacking the first adhesive layer and the second layer. 5. 4. The adhesive sheet for manufacturing a semiconductor device according to claim 3, wherein a central part inside the peripheral part is formed by the second layer. 5. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein the adhesive sheet is formed by stacking the first adhesive layer and the second layer. 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.

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