JPH10310749A - Adhesive film for semiconductor wafer dicing, and dicing of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject film capable of preventing the chip in dicing from causing dispersion, etc., by adjusting the subject film to have an adhesive layer containing a base polymer of a specific constitution and a crosslinking agent, and to have a specific sticking characteristic for the temperature change. SOLUTION: The objective adhesive film is the one having a sticker layer containing 100 pts.wt. base polymer obtained by copolymerizing (A) 40-98 wt.% at least one kind of monomer having a structure of the formula [R1 is H or CH3 ; X is COOR2 (R2 is a 10-50C aliphatic group), etc.], (B) 1-30 wt.% monomer having a functional group capable of reacting with a cross-linking agent, and (C) 1-59 wt.% monomer copolymerizable with the components A and B, and 0.1-5 pts.wt. crosslinking agent. The sticking power to the SUS 304-BA board is 150-2000 g/25 mm at A deg.C-40 deg.C and 100 g/25 mm at B deg.C-C deg.C [0<A deg.C<40 deg.C and (-50) deg.C <=B deg.C<=C deg.C<=(A-3) deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive film for dicing a semiconductor wafer and a method for dicing a semiconductor wafer using the adhesive film. More specifically, an adhesive film for dicing a semiconductor wafer having an adhesive layer whose adhesive force changes dramatically due to a temperature change, and a method of mounting the adhesive film on a surface of a semiconductor wafer such as a silicon wafer on which an integrated circuit is incorporated ( The semiconductor wafer is fixed by attaching to a surface (hereinafter, referred to as a wafer back surface) opposite to the wafer front surface (hereinafter, referred to as a wafer back surface), divided into element pieces, and separated and taken out for each element (hereinafter, a pickup and a pickup). Say) how about.

[0002]

2. Description of the Related Art Normally, a semiconductor integrated circuit is formed by slicing a high-purity silicon single crystal or the like into a semiconductor wafer, forming an integrated circuit on the surface thereof by ion implantation, etching, or the like, and further grinding the back surface of the semiconductor wafer. The thickness of the semiconductor wafer is reduced to about 100 to 600 μm by grinding such as polishing, lapping, lapping, and the like, then divided into element pieces (hereinafter, referred to as chips) (hereinafter, referred to as dicing), and the obtained chips are mounted. It is manufactured by a method of incorporating it into a package through processes such as bonding and sealing. Among these processes, in a dicing process for forming a semiconductor wafer into chips, an adhesive film is used to prevent chips from scattering at the time of dicing and to facilitate the dicing process.

[0003] Specifically, an adhesive film is attached to a metal or plastic circular or square frame called a ring frame, and a semiconductor wafer is attached and fixed from the back side thereof. After fixing the semiconductor wafer, the wafer is diced into chips by a rotating round blade (hereinafter referred to as a dicing blade) while water is applied. After dicing, each chip is picked up from the adhesive film. Generally, sticking an adhesive film to a ring frame or semiconductor wafer
This is performed by an automatic sticking device called a wafer mounter, a wafer mount frame manufacturing device, or the like. To pick up the diced chips, expand the adhesive film radially, widen the gap between the chips, push up the chips with a needle or the like through the adhesive film, and suction with a vacuum collet, air tweezers, etc. Is used.

When dicing is performed by sticking the back surface of the semiconductor wafer to an adhesive film and performing dicing, a strong adhesive force that does not cause chips to be scattered during dicing is necessary. At the same time, when chips are picked up from the adhesive film, ,
A weak adhesive strength that can be easily peeled is required.

The performances required of the adhesive film during dicing and picking up are mutually exclusive. If the adhesive force is increased to prevent the chips from scattering during dicing, a problem that the pickup cannot be picked up during picking up (hereinafter, referred to as a problem). , Referred to as pickup failure)
In contrast, if the adhesive force is reduced to prevent a pickup failure, chips may be scattered during dicing. In particular, when chips are scattered, not only does the yield of chips decrease, but the scattered chips may damage expensive dicing blades.In this case, extra work is required for blade replacement work and readjustment. It will be necessary.

As a method for solving these problems, for example, Japanese Unexamined Patent Application Publication No. 60-196965 discloses an adhesive thin plate for fixing a semiconductor wafer at the time of cutting and separating a semiconductor wafer into small pieces, which has a light transmitting property. And a pressure-sensitive adhesive layer provided on the support and having a property of being hardened by light irradiation and formed into a three-dimensional network, is disclosed.

However, the pressure-sensitive adhesive layer (adhesive layer) having the property of being cured by light irradiation and forming a three-dimensional network as disclosed in the publication is a pressure-sensitive adhesive layer which is polymerized by radical polymerization. When oxygen enters between the wafer and the pressure-sensitive adhesive layer, the curing reaction does not proceed sufficiently due to the effect of inhibiting polymerization of oxygen, and the uncured pressure-sensitive adhesive with low cohesive force is applied to the chip when picking up the chip after dicing. There was a case where a surface on which a circuit was not incorporated (hereinafter referred to as a back surface of a chip) was contaminated. Generally, the back surface of a semiconductor wafer has irregularities due to the back surface grinding, and it is impossible to attach the semiconductor wafer without interposing air (oxygen) at all. In addition, a large-scale apparatus and a large cost are required to create a system from which oxygen is removed for application. Such contamination caused by the pressure-sensitive adhesive layer may cause a bonding defect between the chip and the base when the chip is incorporated into a package in the next step (hereinafter, these will be referred to as packaging defects), It may cause a product defect such as affecting the electrical characteristics of the circuit.

Further, in the above invention, ultraviolet rays are substantially used as light to be applied when the pressure-sensitive adhesive film (adhesive film) is peeled off. However, it is said that it is not desirable to use this ultraviolet light from the viewpoint of work environment hygiene, such as causing a disease such as inducing skin cancer or generating ozone.

As a method for solving the above problems (dispersion of chips during dicing, defective pick-up) without using ultraviolet rays, Japanese Patent Application Laid-Open No. 7-263381 discloses an adhesive and a plastic film base material. An adhesive film for dicing a semiconductor wafer used for fixing when dicing a semiconductor wafer, wherein the adhesive has an adhesive force at or above the melting point of which is three times or more the adhesive force at or below the melting point. A dicing method using is disclosed. However, the pressure-sensitive adhesive film disclosed in this publication can solve the problems such as scattering of chips during dicing, defective pickup, and deterioration of the working environment due to the use of ultraviolet rays. May have occurred.

In recent years, as the performance of chips has been improved by increasing the capacity and integration of semiconductor integrated circuits, it has been feared that contamination on the back surface of the chips will affect the electrical characteristics of the semiconductor integrated circuits. Also, when handling expensive high performance chips, it has become necessary to reduce the defective rate of packaging in order to increase the efficiency of productivity. Therefore, not only the prevention of chip scattering at the time of semiconductor wafer dicing and the workability at the time of pickup are balanced, but also the use of the adhesive film for semiconductor wafer dicing and the adhesive film with less contamination on the back surface of the chip. There is a demand for a method of dicing semiconductor wafers.

[0011]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to prevent chips from scattering with a strong adhesive force when dicing a semiconductor wafer and to cool the chips by cooling when picking up. The semiconductor integrated circuit can be easily picked up without lowering the power and reducing the workability, and can be easily picked up.Furthermore, there is almost no contaminant adhering to the back surface of the chip from the adhesive layer after the picking up. An object of the present invention is to provide an adhesive film for semiconductor wafer dicing that can cope with higher performance of chips by high integration and the like, and a semiconductor wafer dicing method using the adhesive film.

[0012]

Means for Solving the Problems As a result of diligent studies, the present inventors have found that a pressure-sensitive adhesive layer having a constitution in which a base polymer obtained by copolymerizing a specific monomer is crosslinked with a crosslinker, and a specific By using an adhesive film adjusted to have adhesive properties, within a specific temperature range, affixed to the backside of the semiconductor wafer and diced, and after dicing, by picking up while cooling to a specific low temperature region In addition, it can prevent chip scattering during dicing, trouble during pickup, and deterioration of the working environment.
The present inventors have found that the above object can be achieved without contaminating the back surface of the chip, and have reached the present invention.

That is, the first invention of the present invention is an adhesive film for dicing a semiconductor wafer having an adhesive layer provided on one side of a base film, which is used for fixing when dividing a semiconductor wafer into element pieces. And the pressure-sensitive adhesive layer has the general formula (1)

[0014]

Embedded image (Wherein, R ₁ is —H or —CH ₃ , X is —COOR ₂ ,
_{-CONHR 3, -OR 4, -OCOR 5} , -R 6 or -
C ₆ H ₄ -R ₇ is shown. Here, R _{2 to} R ₆ have 10 carbon atoms.
50 aliphatic group or at least partially fluorine-substituted aliphatic group having a carbon number of 6 to 50,, R ₇ has a carbon number 8
At least one monomer (I) selected from the group consisting of monomers having the following structures:
8% by weight, 1 to 30% by weight of a monomer (II) having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent, and 1 to 59% by weight of a monomer (III) copolymerizable with the monomers (I) and (II)
And 100% by weight of a base polymer obtained by copolymerizing a monomer mixture containing, as an essential component,
A to 40 ° C. (0 ° C. <A ° C. <40
C) in a temperature range of 150 to 2,000 when the adhesive force is applied to the SUS304-BA plate in the temperature range.
0 ° C./25 mm, B ° C. to C ° C. [−50 ° C. ≦ B ° C. ≦ C ° C.
SUS30 when cooled to the temperature range of (A-3) ° C]
An adhesive film for dicing a semiconductor wafer, wherein the adhesive strength to a 4-BA plate is 100 g / 25 mm or less.

According to a second aspect of the present invention, when the semiconductor wafer is divided into element pieces, an adhesive film is attached to the back surface thereof,
A method for dicing a semiconductor wafer, in which the element pieces obtained from the pressure-sensitive adhesive film are separated and picked up after the division, wherein the pressure-sensitive adhesive film for semiconductor wafer dicing is applied to the back surface of the semiconductor wafer at a temperature of A ° C to 40 ° C (0 ° C < A ℃ <
40 ° C.), the semiconductor wafer is divided while applying cooling water kept in the temperature range, and then B ° C. to C ° C. [−50 ° C. ≦ B ° C. ≦ C ° C. ≦ (A -3)
[C] after cooling to a temperature range of [° C], the element pieces are separated from the adhesive film and picked up.

When the semiconductor wafer is diced in a temperature range of A ° C. to 40 ° C. (0 ° C. <A ° C. <40 ° C.), the adhesive film for dicing a semiconductor wafer of the present invention has a strong adhesive force on the back surface of the semiconductor wafer. Adhere to prevent chip scattering. Further, after completion of dicing, when the obtained chip is picked up, B ° C to C ° C [−50 ° C ≦ B ° C.
≦ C ° C. ≦ (A-3) ° C.] can reduce the adhesive strength.

Therefore, it is possible to prevent a trouble at the time of pickup such as a pickup failure. After pickup, contaminants due to the adhesive layer hardly adhere to the back surface of the chip, and an excellent effect of preventing contamination of the back surface of the chip is exhibited. Therefore, according to the present invention, there is provided a method capable of efficiently producing a semiconductor integrated circuit with higher performance with a high yield. Also, the working environment is not deteriorated.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The first invention of the present invention is a pressure-sensitive adhesive film for semiconductor wafer dicing (hereinafter referred to as pressure-sensitive adhesive film) whose adhesive force can change drastically with a change in temperature. In the second invention, the pressure-sensitive adhesive film is formed from A ° C to 40 ° C (0 ° C
<A ° C. <40 ° C.) and adhered to the back surface of a semiconductor wafer (hereinafter referred to as a wafer) via an adhesive layer in a temperature range of
Further, chips are prevented from being scattered by dicing the semiconductor wafer while applying cooling water within the temperature range, and then, a temperature range of B ° C. to C ° C. [−5] lower than the temperature range.
A semiconductor wafer dicing method characterized in that the semiconductor chip is cooled to a temperature range of 0 ° C. ≦ B ° C. ≦ C ° C. ≦ (A-3) ° C., and the obtained chip is picked up while maintaining a cooled state.

First, the method for producing the pressure-sensitive adhesive film of the present invention will be described. The pressure-sensitive adhesive film of the present invention is obtained by applying a pressure-sensitive adhesive solution or an emulsion solution (hereinafter, referred to as a pressure-sensitive adhesive coating solution) containing a component constituting a pressure-sensitive adhesive layer to a base film and drying the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer. Manufactured. In this case, it is preferable to attach a release film to the surface of the pressure-sensitive adhesive layer in order to protect the pressure-sensitive adhesive layer from contamination caused by the environment. Also, a method of applying a pressure-sensitive adhesive on one surface of a release film and drying to form a pressure-sensitive adhesive layer, then attaching a substrate film to the surface of the pressure-sensitive adhesive layer and transferring the pressure-sensitive adhesive layer to the substrate film side It is also manufactured by In this case, there is an advantage that the surface of the pressure-sensitive adhesive layer is not contaminated when the pressure-sensitive adhesive layer is dried.

Whether to apply the pressure-sensitive adhesive coating solution to one surface of the base film or the release film is determined in consideration of the heat resistance, surface tension, contamination on the back surface of the wafer, and the like of the base film and the release film. . For example, when the heat resistance of the release film is superior to that of the base film, an adhesive layer is provided on the surface of the release film and then transferred to the base film. If the heat resistance is equivalent or the base film is better, provide an adhesive layer on the surface of the base film,
A release film is attached to the surface. However, considering that the adhesive film is attached to the back surface of the semiconductor wafer via the surface of the adhesive layer exposed when the release film is peeled off, in order to prevent contamination of the wafer back surface by the adhesive layer, A method is preferred in which a release film having good heat resistance is used, and a pressure-sensitive adhesive coating solution is applied to the surface thereof and dried to form a pressure-sensitive adhesive layer.

Examples of the base film used for the pressure-sensitive adhesive film of the present invention include films produced from synthetic resins, natural rubbers, synthetic rubbers and the like. To give a concrete example,
Ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, polybutadiene, soft vinyl chloride resin, polyolefin, polyester, polyamide, ionomer, and other resins, and their copolymer elastomers, and diene, nitrile, and silicone And films of synthetic rubber such as acryl based. The base film may be a single layer or a laminate. The thickness of the base film affects the loosening of the adhesive film when dicing the wafer, the workability of sticking to the back surface of the wafer and the ring frame, and the expandability. From such a viewpoint, the thickness of the base film is usually 30 to 600 μm. Preferably it is 40 to 300 μm.

Considering the expandability of the pressure-sensitive adhesive film in the expanding step usually performed when picking up chips, JIS K 7113-1995 or JIS
The tensile breaking strength measured in accordance with K6760-1995 is 0.8 to 6 kgf / mm ² , and the tensile breaking elongation is 100
What processed the resin of ~ 2000% into a film shape is preferable. For example, films such as ionomers and ethylene-methacrylic acid copolymers are preferably used. In order to improve the adhesive strength between the substrate film and the pressure-sensitive adhesive layer, it is preferable to subject the surface of the substrate film on which the pressure-sensitive adhesive layer is provided to a corona discharge treatment or a chemical treatment. An undercoat may be used between the base film and the pressure-sensitive adhesive layer.

Examples of the release film disposed on the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention include synthetic resin films such as polypropylene and polyethylene terephthalate. Preferably, the surface thereof is subjected to a silicone treatment or the like as necessary. The thickness of the release film is usually 20 to
It is 300 μm. Preferably it is 30 to 100 μm.

The pressure-sensitive adhesive layer used in the pressure-sensitive adhesive film of the present invention is a pressure-sensitive adhesive layer having a constitution in which a base polymer obtained by copolymerizing a monomer mixture having a specific constitution is crosslinked with a specific amount of a crosslinking agent. -40 ° C (0 ° C <A ° C
In the temperature range of <40 ° C.), it exhibits sufficient adhesive strength to prevent chips from being scattered during wafer dicing, and has a low-temperature range outside the temperature range of B ° C. to C ° C. [−50 ° C. when picking up the obtained chips. ≦ B ° C ≦ C ° C ≦ (A-3) ° C]
By cooling to the temperature range described above, the adhesive force is reduced, and the pickup can be easily performed without causing a pickup failure.

The base polymer has the general formula (1)

[0026]

Embedded image (Wherein, R ₁ is —H or —CH ₃ , X is —COOR ₂ ,
_{-CONHR 3, -OR 4, -OCOR 5} , -R 6 or -
C ₆ H ₄ -R ₇ is shown. Here, R _{2 to} R ₆ have 10 carbon atoms.
50 aliphatic group or at least partially fluorine-substituted aliphatic group having a carbon number of 6 to 50,, R ₇ has a carbon number 8
At least one monomer (I) selected from the group of monomers having the following structures: (i) an alkyl group having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent; It is obtained by copolymerizing a monomer mixture containing a monomer (III) copolymerizable with II) as an essential component.

Specific examples of the monomer (I) include acrylates, methacrylates, and acrylamides having an aliphatic group having 10 to 50 carbon atoms or an aliphatic group having at least a part of which is substituted by fluorine and having 6 to 50 carbon atoms. At least one monomer selected from derivatives, methacrylamide derivatives, vinyl ether derivatives, vinyl ester derivatives, α-olefins and derivatives thereof, and styrene derivatives having an alkyl group having 8 to 24 carbon atoms. .

Among these, acrylates, methacrylates, and acrylamide derivatives having a linear aliphatic group having 14 to 50 carbon atoms in consideration of the temperature dependence of the adhesive properties, polymerization reactivity, availability of monomers, and the like. And the same methacrylamide derivatives are preferred. More preferred are acrylates, methacrylates, acrylamide derivatives, and methacrylamide derivatives having a linear aliphatic group having 14 to 22 carbon atoms. Particularly preferably, it has 14 to 14 carbon atoms.
Acrylates and methacrylates having 18 linear aliphatic groups.

The monomer (I) is preferably contained in an amount of 40 to 98% by weight based on the total amount of all the monomers used as the base polymer raw materials. More preferably, it is 50 to 98% by weight, still more preferably 60 to 98% by weight. As the weight due to the monomer (I) in the pressure-sensitive adhesive layer increases, the
The adhesive strength when cooled to a temperature range of ~ C ° C tends to decrease.

Specific examples of the monomer (II) having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent include acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, citraconic acid, fumaric acid, maleic acid and monoalkyl itaconate. Monoalkyl mesaconate, monoalkyl citraconic, monoalkyl fumarate, monoalkyl maleate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate And at least one selected from tert-butylaminoethyl methacrylate and the like. The monomer (II) is used in consideration of the amount of the monomer (I) used, and is 1 to 30% by weight based on the total amount of all monomers used as the base polymer raw material.
It is used so as to be contained in the range.

The monomer (III) is prepared by converting the monomer (I)
And those copolymerizable with the monomer (II).
Specific examples include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc., having 1 to 8 carbon atoms. At least one selected from the group consisting of alkyl acrylates or alkyl methacrylates having an alkyl group of the following, vinyl acetate, acrylonitrile, styrene and the like.

Among them, the alkyl acrylate or alkyl methacrylate having an alkyl group having 1 to 8 carbon atoms has the effect of increasing the polymerization rate of the base polymer and lowering the production cost of the base polymer, as well as being obtained. This is preferable in that it has an effect of increasing the molecular weight of the base polymer (the pressure-sensitive adhesive layer is less likely to contaminate the wafer by increasing the molecular weight of the base polymer). The monomer (III) is used in such a manner that it is contained in the range of 1 to 59% by weight in the total amount of all monomers to be used as the base polymer raw material in consideration of the amount of the monomer (I) and the monomer (II). Is done.

Further, in addition to the monomers (I), (II) and (III), glycidyl acrylate, glycidyl methacrylate, isocyanate ethyl acrylate, isocyanate ethyl methacrylate,
2- (1-aziridinyl) ethyl acrylate, 2-
A monomer having a self-crosslinking functional group such as (1-aziridinyl) ethyl methacrylate and a polyfunctional monomer such as divinylbenzene, vinyl acrylate, vinyl methacrylate, allyl acrylate, and allyl methacrylate are appropriately used. They may be combined.

As a method for polymerizing the base polymer,
Various known methods such as a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method can be employed. Examples of the polymerization reaction mechanism include radical polymerization, anionic polymerization, and cationic polymerization, and it is preferable to perform polymerization by radical polymerization in consideration of production costs and the like. When polymerized by a radical polymerization reaction, as a radical polymerization initiator, organic compounds such as benzoyl peroxide, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, di-tert-butyl peroxide, di-tert-amyl peroxide, etc. Inorganic peroxides such as peroxides, ammonium persulfate, potassium persulfate, and sodium persulfate;
Examples include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, and 4,4'-azobis-4-cyanovaleric acid. These are appropriately selected according to the properties of the obtained base polymer and the polymerization method.

In consideration of the contamination on the back surface of the wafer, the higher the molecular weight of the base polymer is, the more preferable it is. Therefore, the weight average molecular weight is 300,00 in terms of polystyrene.
0 to 1,500,000 is preferred. More preferably 5
00,000 to 1,500,000.

In the present invention, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film contains a crosslinking agent as an essential component in addition to the base polymer. By containing a crosslinking agent, the base polymer is crosslinked, and it becomes difficult to contaminate the back surface of the wafer. In addition, the content of the crosslinking agent in an appropriate amount varies depending on the state of the unevenness of the wafer,
When the adhesive film is peeled off by cooling after the wafer dicing, there is also an effect that the adhesive strength is easily reduced.

Examples of the cross-linking agent include tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylolpropane adduct of toluene diisocyanate.
Isocyanate compounds such as polyisocyanate, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, resorcin diglycidyl ether, etc. Epoxy compounds, trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis (1- Aziridinecarboxamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide), N, N'-toluene-2,4-bis (1-
Aziridine compounds such as aziridinecarboxamide) and trimethylolpropane-tri-β- (2-methylaziridine) propionate; and melamine compounds such as hexamethoxymethylolmelamine. These may be used alone or in combination of two or more.

The content of the crosslinking agent is 0.1 to 5 parts by weight based on 100 parts by weight of the base rimer. More preferably, it is 0.1 to 3 parts by weight. When the content of the crosslinking agent is small,
When the chip is picked up, a part of the pressure-sensitive adhesive layer tends to remain on the back surface of the chip and become contaminated. When the content is large, the adhesion between the back surface of the wafer and the chip and the pressure-sensitive adhesive layer is deteriorated at A ° C. to 40 ° C., and the chips tend to be scattered during dicing. Furthermore, even if the content of the crosslinking agent is too large, the decrease in the adhesive strength during cooling may be insufficient, and a pickup failure may occur during chip pickup.

In consideration of the above, the properties of the base polymer, the conditions for using the adhesive film (the state of the back surface of the wafer or chip, the shape of the chip, the size of the chip,
Dicing conditions, etc.) and the thickness of the pressure-sensitive adhesive layer described later, etc. are taken into consideration and appropriately contained within the above range.

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film of the present invention may appropriately contain a plasticizer, a tackifier, a stabilizer, a normal pressure-sensitive adhesive, etc., in addition to the base polymer and the crosslinking agent.
The thickness of the pressure-sensitive adhesive layer is appropriately determined according to the state of the back surface of the wafer or chip, the shape of the chip, the size of the chip, dicing conditions, etc., but the adhesive force when dicing the semiconductor wafer, after the dicing is completed Taking into account the characteristics of picking up the obtained chip, usually 2 to 10
It is about 0 μm. Preferably it is 5-70 μm, more preferably 5-30 μm.

As a method for applying the pressure-sensitive adhesive to one surface of the base film or the release film, conventionally known coating methods, for example, a roll coater method, a reverse roll coater method, a gravure roll coater method, a bar coater method, a comma coater Method, die coater method or the like can be adopted. The drying conditions of the applied pressure-sensitive adhesive coating liquid are not particularly limited, but generally, the drying is performed at 80 to 200 ° C. for 10 seconds to 10 seconds.
It is preferable to dry for minutes. More preferably 80 to
Dry at 170 ° C. for 15 seconds to 5 minutes. In order to sufficiently promote the crosslinking reaction between the crosslinking agent and the base polymer,
After the drying of the coating solution for the pressure-sensitive adhesive, the pressure-sensitive adhesive film may be heated at 40 ° C to 80 ° C for about 5 to 300 hours.

Thus, the pressure-sensitive adhesive film according to the present invention produced as described above has a temperature of at least A ° C to 40 ° C.
(0 ° C <A ° C <40 ° C)
The adhesive strength in the temperature range when adhered to a 4-BA plate is 150 to 2,000 g / 25 mm, and the adhesive strength is B ° C to C ° at the time of peeling [−50 ° C ≦ B ° C ≦ C ° C. ≤
(A-3) ° C.] to a temperature range of 100 ° C.
g / 25 mm or less.
The higher the adhesive strength in the temperature range of A ° C. to 40 ° C., the better, and therefore the preferred adhesive strength is 200 to 2000 g / 2.
5 mm, more preferably 250-2000 g / 25 mm
It is. In addition, B ° C which is a lower temperature range than the above temperature range.
The lower the adhesive strength when cooled to the temperature range of ＣC ° C. [−50 ° C. ≦ B ° C. ≦ C ° C. ≦ (A-3) ° C.], the lower the better. Therefore, the preferred adhesive strength when cooled to B ° C. to C ° C. is 80 g / 25 mm or less, more preferably 50 g / 25 mm or less.
It is 25 mm or less.

The adhesive strength is appropriately adjusted within the above range in consideration of the size and shape of the chip obtained by dicing, the dicing time, the back surface shape of the wafer and the chip, and the like. Thus, the chips are not scattered from the step of attaching the adhesive film to the back surface of the wafer, through the dicing step of the wafer, and immediately before the step of picking up the obtained chips, and the chips are not scattered. When picking up, by cooling to a temperature range of B ° C. to C ° C., it is possible to pick up without causing a pick-up failure.

The values of the temperatures A.degree. C. and C.degree.
Adjustment by changing the composition of the pressure-sensitive adhesive layer
Can be. Among them, especially the values of A ° C. and C ° C.
Tend to depend on the configuration. In particular, of the monomer (I)
It changes greatly depending on the type and amount. For example, monomer
R in the general formula (1) of (I)_Two, R_Three, R_Four, R_Five, R
₆, R₇As the number of carbon atoms increases, the value of A ° C. increases
There is a tendency. Accordingly, the value of C ° C. increases accordingly.
Become a trend. Further, when the amount of the monomer (I) is large, A
-(A-3) of the pressure-sensitive adhesive film at a temperature change around
The adhesive property change becomes sharp, and C ° C approaches (A-3) ° C.
It tends to be.

In the present invention, the range of A is 0 ° C. <A ° C.
It is necessary to adjust the properties of the pressure-sensitive adhesive film so as to be in the range of <40 ° C. Further, within this range, considering the working environment when attaching the adhesive film, the temperature control of the cooling water used at the time of dicing, etc., 0 ° C <A ° C ≦ 15 ° C
Is preferably adjusted to the range described above. B ° C and C
The range of ° C. is -50 ° C. in consideration of the cost of the equipment required for cooling, the load on the semiconductor chip due to cooling (strain may be caused by rapidly cooling the chip, and the chip may be damaged). As described above, it is preferable to adjust the properties of the pressure-sensitive adhesive film, more preferably-
10 ° C. or higher. Further, when the temperature exceeds 0 ° C., the cost required for cooling is reduced, which is particularly preferable. Further, the range of B ° C. to C ° C. is preferably wider as the temperature control during cooling becomes easier. However, if the adhesive strength falls within the range of the present application when cooled within the above range, the range of B ° C. to C ° C. may be narrow, and B ° C. may be equal to C °. However, when the temperature range is narrow, it is necessary to more accurately control the temperature during cooling. Above, most preferred A
To summarize the relationship between ° C, B ° C and C ° C, 0 ° C <B ° C ≤ C
C. ≦ (A−3) ° C. and A ° C. ≦ 15 ° C.

The method for producing the pressure-sensitive adhesive film of the present invention is as described above. From the viewpoint of preventing contamination of the back surface of the wafer or chip, the production environment of the raw materials such as the base film and the release film and the adjustment of the pressure-sensitive adhesive coating liquid are adjusted. , Storage, application and drying environment,
It is preferable to maintain the cleanliness of class 1,000 or less specified in US Federal Standard 209b.

Next, the wafer dicing method of the present invention will be described. The method of dicing a wafer according to the present invention includes:
The pressure-sensitive adhesive film described above, a specific temperature range A ° C. ~
At a temperature of 40 ° C. (0 ° C. <A ° C. <40 ° C.), dicing is performed while cooling water in the temperature range is applied, and when a chip obtained after the dicing is completed is picked up, a specific Temperature range B ° C to C ° C [-5
It is characterized in that the pickup is performed in a state of cooling to 0 ° C ≦ B ° C ≦ C ° C ≦ (A-3) ° C].

More specifically, first, the release film is peeled from the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film to expose the surface of the pressure-sensitive adhesive layer, and at a temperature range of A ° C. to 40 ° C. (0 ° C. <A ° C. <40 ° C.) It is adhered to a metal or plastic ring frame via the adhesive layer. Then, the wafer is attached to the adhesive film in the frame of the ring frame from the back surface. Thereafter, the wafer is divided (diced) into chips while applying cooling water in a temperature range of A ° C. to 40 ° C. with a dicing blade for the purpose of removing frictional heat and removing wafer cuttings. After completion of dicing, B ° C to C ° C
The temperature is cooled to a temperature range of [−50 ° C. ≦ B ° C. ≦ C ° C. ≦ (A-3) ° C.], and a chip obtained in a cooled state is picked up.

After the dicing of the wafer is completed, before picking up the obtained chips, a step (expanding step) of expanding the adhesive film radially and widening the interval between the chips may be performed.

The operation of attaching the adhesive film to the back surface of the wafer may be performed manually, or may be performed using an apparatus for attaching the adhesive film to the wafer, which is called a wafer mounter or a wafer mount manufacturing apparatus. You may. Examples of such a device include, for example, model AT
M-8100 and the like. The temperature at the time of sticking is A ℃ ～ 4
As a method of controlling the temperature to 0 ° C. (0 ° C. <A ° C. <40 ° C.), various known methods can be employed. For example, when the A ° C. is lower than the normal working environment (about 15 ° C. to 30 ° C.), the working environment It is easy to control the temperature to be in the temperature range,
preferable.

As the dicing method, a known method is adopted. For example, there is a full cut method in which a wafer is completely divided into chips by a dicing blade. Dicing is performed while cooling water is applied to a dicing blade or the like.
It is necessary to control to 40 ° C. The temperature control method of the cooling water is, for example, in a thermostat controlled at A ° C to 40 ° C.
Various known methods such as passing cooling water may be used. Examples of the dicing apparatus include DFD-2S / 8 manufactured by Disco Corporation.

After completion of dicing, expanding is performed if necessary, and then the pressure-sensitive adhesive film is heated to a temperature of B ° C. to C ° C. [−
50 ° C ≦ B ° C ≦ C ° C ≦ (A-3) ° C], and the chip obtained in the cooled state is picked up. The pick-up operation may be performed manually, but is generally performed by a method in which the tip is pushed up by a needle or the like and is suctioned by a vacuum collet, air tweezers, or the like. As a method of cooling the pressure-sensitive adhesive film, cold air is applied from the substrate side or chip side of the pressure-sensitive adhesive film,
There are various known methods. The temperature between B ° C and C ° C is 0
When the pressure-sensitive adhesive film is adjusted so as to exceed ℃, it is advantageous in terms of cost required for cooling.

According to the present invention, when dicing a wafer, chips are not scattered during dicing because the adhesive film firmly holds the chips. In addition, the scattered chips do not damage the expensive dicing blade. Further, since cooling after the dicing is finished, the peeling adhesive strength of the adhesive film is reduced, so that a pick-up failure does not occur when picking up the obtained chip, and the back surface of the chip is not contaminated. Therefore, the yield of the semiconductor chips whose performance is improved is improved, and production at low cost becomes possible.

As a semiconductor wafer to which the present invention can be applied,
Not only silicon wafers, but also germanium and gallium
Semiconductor wafers of arsenic, gallium-phosphorus, gallium-arsenic-aluminum, and the like can be given. Of these, when applied to a semiconductor wafer that has an uneven back surface due to back surface grinding or the like and the chip unit price tends to be expensive due to high performance, particularly compared to the conventional wafer dicing adhesive film. Has excellent effects.

As a modification of the present invention, the adhesive film of the present invention can be applied to wafers other than semiconductor wafers, such as optical glass and ceramic substrates. In the present invention, in the case of a wafer other than a semiconductor wafer such as an optical glass or a ceramic substrate, a surface of the wafer to be bonded to the adhesive film for wafer dicing is referred to as a back surface.

[0056]

The present invention will be described below in further detail with reference to examples. In the following Examples and Comparative Examples,
The production of adhesive films for semiconductor wafer dicing (after the preparation of the adhesive coating solution) and the dicing of semiconductor wafers using the adhesive films for semiconductor wafer dicing are all performed to a cleanliness level of 1,000 or less specified in US Federal Standard 209b. Performed in a maintained environment. The present invention is not limited to these examples.

The performance of the obtained pressure-sensitive adhesive film and each characteristic in a semiconductor wafer dicing method using the film were evaluated by the following methods (1) to (3). (1) Percentage of chips scattered during dicing (%) A semiconductor silicon wafer (diameter: 6 inches, thickness: 300) on which a 5 mm square integrated circuit is formed on the surface and the back surface is finished
μm), the adhesive films obtained in Examples and Comparative Examples were adhered at 23 ° C., respectively. After sticking, using a dicing device [manufactured by Disco: Free Automatic Dicing Saw, Model: DFD-2S / 8],
Full-cut dicing was performed for each circuit while cooling with water at 23 ° C. The same dicing operation was performed three times using three semiconductor silicon wafers for each example and comparative example. At this time, the number of scattered chips was counted, and the ratio (%) of scattered chips was determined. Furthermore, the state of breakage of the dicing blade after dicing was observed.

(2) Pickup defect rate (%) After the dicing of the above (1), the pressure-sensitive adhesive film is cooled to 5 ° C., and while maintaining this temperature, the pressure-sensitive adhesive film is pushed up with a needle from the base film side of the pressure-sensitive adhesive film. The chips were picked up by suction with air tweezers. The ratio (%) of the chips that could not be picked up to the number of chips that did not scatter in (1) above was determined.

(3) Observation of contamination on the back surface of the chip by a microscope (%) For the chip picked up in the above (2), the back surface of the chip is optical microscope [OPTIPHO manufactured by Nikon Corporation:
T2], observation was performed in the range of 50 to 1000 times, and the number of contaminated chips was counted. The ratio (%) of the contaminated chip to the picked-up chip was evaluated.

(4) Adhesive force (g / 25 mm) characteristics JIS Z 0237-1 except for the conditions specified below.
991. The adhesive films obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were placed on the SUS304-BA plate (vertical:
(20 cm, width: 5 cm) and left for 1 hour. After standing, -10 ° C, -5 ° C, 0 ° C, 3 ° C, 7 ° C, 1
At 0 ° C., 15 ° C., 23 ° C., and 40 ° C., one end of the sample was sandwiched, and a peeling angle: 180 ° and a peeling speed: 300 mm /
min. The sample was peeled off from the surface of the SUS304-BA plate at, and the stress at the time of peeling was measured and converted to g / 25 mm. From the measured adhesive strength to the high adhesive strength temperature range (A ° C ~
(40 ° C.) and a low temperature range (B ° C. to C ° C.) and the adhesive strength in each temperature range. The adhesive properties (23 ° C.) of the adhesive film obtained in Comparative Example 4 were also measured according to the above method (details are described in Comparative Example 4).

Preparation Example <Synthesis of base polymer 1> Tetradecyl acrylate [monomer (I)] 75 parts by weight, 2-hydroxyethyl methacrylate [monomer (II)] 2 parts by weight, acrylic acid [monomer (II)] 1 Parts by weight, 12 parts by weight of butyl acrylate [monomer (III)], 10 parts by weight of ethyl acrylate [monomer (III)], and 0.05 parts by weight of azobisisobutyronitrile (AIBN) as an initiator. And 70 ° C. in 100 parts by weight of ethyl acetate under a nitrogen atmosphere.
To obtain a solution of the base polymer 1 (solid content: 50% by weight). The weight average molecular weight of the obtained base polymer 1 was determined by gel permeation chromatography (GP
When measured in C), it was about 700,000 in terms of polystyrene. <Synthesis of base polymers 2 to 5> A solution of base polymers 2 to 5 having the molecular weights shown in [Table 1] in the same manner as in the synthesis of base polymer 1 except that the monomer mixture shown in [Table 1] was used. (Solid content 50% by weight) was obtained. The weight average molecular weight of each base polymer was measured in the same manner as for base polymer 1, and the results are shown in [Table 1].

[0062]

[Table 1]

Example 1 A solution of the base polymer 1 obtained in the preparation example (solid content: 50%)
100 parts by weight) of 100 parts by weight of ethyl acetate and 50 parts by weight of an isocyanate-based crosslinking agent [Olester P-49-75S, manufactured by Mitsui Toatsu Chemicals, Inc. (solid content: 75% by weight)].
13 parts by weight (0.1 part by weight as a solid content of a crosslinking agent) was added to prepare an adhesive coating solution. This coating solution was applied to one side of a polypropylene film (release film, thickness: 50 μm) using a roll coater, and dried at 120 ° C. for 1 minute to provide a 10 μm thick adhesive layer. Next, an ethylene-methacrylic acid copolymer base film having a thickness of 120 μm subjected to corona discharge treatment (methacrylic acid content: 10 wt.
%) By applying and pressing the treated surfaces to transfer the pressure-sensitive adhesive layer, thereby producing a pressure-sensitive adhesive film. The adhesive property of the obtained adhesive film was 3 ° C. in the range of 15 ° C. to 40 ° C.
An adhesive strength of 50 to 450 g / 25 mm was exhibited. further,
The adhesive strength when it was stuck on a SUS304-BA plate at 23 ° C and cooled to 3 ° C to 7 ° C was 30 to 50 g / 25 mm. The obtained adhesive film was heated at 23 ° C. for 5 m.
An integrated circuit having an m-square is formed and attached to the back surface of a semiconductor silicon wafer (diameter: 6 inches, thickness: 300 μm) on which the back surface has been ground, and a dicing apparatus [manufactured by Disco: Free Automatic Dicing Saw, type: DFD- 2S
/ 8], full-cut dicing was performed for each circuit while cooling with 23 ° C. water. After the dicing, the chip was cooled to around 5 ° C., pushed up with a needle from the substrate film side, and picked up by suction with air tweezers. The same dicing operation was performed three times using three semiconductor silicon wafers. There were no chips scattered during dicing, and no pickup failure occurred. The back surface of the chip after the pick-up is measured using an optical microscope [OPTIPHOT2 manufactured by Nikon Corp.]
When observed in a range of ~ 1000 times, no chips were contaminated. The results are shown in [Table 2].

Examples 2 to 6 and Comparative Examples 1 to 3 An adhesive film was produced by the same operation as in Example 1 except for the conditions shown in Table 2, and dicing and pickup were performed by the same operation. . The physical properties, dicing results and the like of the obtained pressure-sensitive adhesive film are shown in [Table 2].

Comparative Example 4 91 parts by weight of butyl acrylate, 4.5 of acrylonitrile
Parts by weight, 4.5 parts by weight of acrylic acid, and 150 parts by weight of toluene in 1 part by weight of 2,2'-azobis-isobutyronitrile (hereinafter referred to as AIBN) under nitrogen atmosphere.
Copolymerization was performed at 0 ° C. to obtain a base polymer solution (solid content: 40% by weight). 100 parts by weight of this base polymer solution (solid content 40% by weight) is added to an isocyanate-based crosslinking agent [Mitsui Toatsu Chemical Co., Ltd., Olester P-49-75].
S, (solid content: 75% by weight)], 2 parts by weight (1.5 parts by weight as a cross-linking agent solid content), 6 parts by weight of dipentaerythritol monohydroxypentaacrylate and 0.4 part by weight of α-hydroxycyclohexyl phenyl ketone. This was added to prepare an adhesive coating solution. This coating solution was applied to one surface of a polypropylene film (release film, thickness: 50 μm) using a roll coater, and dried at 120 ° C. for 1 minute to provide a 15 μm thick adhesive layer. Next, an ethylene-methacrylic acid copolymer base film having a thickness of 120 μm subjected to corona discharge treatment (methacrylic acid content: 10 wt.
%) By applying and pressing the treated surfaces to transfer the pressure-sensitive adhesive layer, thereby producing a pressure-sensitive adhesive film. The obtained adhesive film showed an adhesive force of 450 g / 25 mm to the SUS304-BA plate at 23 ° C. 23 ° C
Then, after adhering to a SUS304-BA plate and allowing to stand for 1 hour, ultraviolet rays generated from a high-pressure mercury lamp (40 W / cm) from the ethylene-methacrylic acid copolymer base film side were irradiated for 15 c.
After light irradiation for 20 seconds from a distance of m, the adhesive strength when peeled off was 80 g / 25 mm. A semiconductor silicon wafer (diameter: 6 inches, diameter: 6 inches, on which an integrated circuit of 5 mm square was formed at 23 ° C.
Attached to the back surface with a thickness of 300 μm), using a dicing device [manufactured by Disco Corporation: Free Automatic Dicing Saw, Model: DFD-2S / 8], applying water at 23 ° C. and cooling, and cutting the entire circuit. Dicing. After dicing, a 1-inch high pressure mercury lamp (40 W / cm) was applied from the ethylene-methacrylic acid copolymer base film side.
After irradiating light for 20 seconds from a distance of 5 cm, the chip was picked up by pushing up from the substrate film side with a needle and adsorbing with air tweezers. The same dicing operation was performed three times using three semiconductor silicon wafers. There were no chips scattered during dicing, and no pickup failure occurred. An optical microscope [Nikon Corporation: OPTIPHO]
As a result of observation using T2] in a range of 50 to 1000 times, 1% of the chips were contaminated by the pressure-sensitive adhesive layer. The results are shown in [Table 2].

[0066]

[Table 2]

[0067]

The pressure-sensitive adhesive film for dicing a semiconductor wafer according to the present invention has a pressure-sensitive adhesive layer containing a base polymer and a cross-linking agent having a specific structure. When dicing a semiconductor wafer, chips are scattered with a strong pressure. It is characterized in that it has a property that the adhesive strength is easily reduced only by cooling when picking up. Therefore, when a semiconductor wafer is diced using the adhesive film, chips are not scattered during the dicing, and the diced blade is not damaged by the scattered chips. Further, since the peeling stress is small, the picked-up chip can be easily picked up without causing a pick-up failure when picking up the obtained chip. Further, contaminants from the pressure-sensitive adhesive layer hardly adhere to the back surface of the chip after pickup. Therefore, in the technical field of high performance, the present invention exerts excellent effects such as improvement in yield and reduction in manufacturing cost.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 133/06 C09J 133/06 133/26 133/26 H01L 21/301 H01L 21/78 N (72) Inventor Hideki Fukumoto Aichi 2-1, Tango-dori, Minami-ku, Nagoya-shi Mitsui Toatsu Chemicals Co., Ltd.

Claims (4)

[Claims] 1. An adhesive film for dicing a semiconductor wafer, wherein an adhesive layer is provided on one side of a base film, which is used for fixing when a semiconductor wafer is divided into element pieces. General formula (1) (Wherein, R ₁ is —H or —CH ₃ , X is —COOR ₂ ,
_{-CONHR 3, -OR 4, -OCOR 5} , -R 6 or -
C ₆ H ₄ -R ₇ is shown. Here, R _{2 to} R ₆ have 10 carbon atoms.
50 aliphatic group or at least partially fluorine-substituted aliphatic group having a carbon number of 6 to 50,, R ₇ has a carbon number 8
At least one monomer (I) selected from the group consisting of monomers having the following structures:
8% by weight, 1 to 30% by weight of a monomer (II) having a functional group capable of undergoing a crosslinking reaction with a crosslinking agent, and 1 to 59% by weight of a monomer (III) copolymerizable with the monomers (I) and (II)
And 100% by weight of a base polymer obtained by copolymerizing a monomer mixture containing, as an essential component,
A to 40 ° C. (0 ° C. <A ° C. <40
C) in a temperature range of 150 to 2,000 when the adhesive force is applied to the SUS304-BA plate in the temperature range.
0 ° C./25 mm, B ° C. to C ° C. [−50 ° C. ≦ B ° C. ≦ C ° C.
SUS30 when cooled to the temperature range of (A-3) ° C]
An adhesive film for dicing a semiconductor wafer, wherein the adhesive strength to a 4-BA plate is 100 g / 25 mm or less. 2. The relationship between A ° C., B ° C. and C ° C. is 0 ° C. <B
The pressure-sensitive adhesive film for dicing a semiconductor wafer according to claim 1, wherein the temperature satisfies the relationship: ≤ C ≤ C ≤ (A-3) deg. 3. A dicing method for a semiconductor wafer, wherein when a semiconductor wafer is divided into element pieces, an adhesive film is attached to the back surface thereof, and after the division is completed, the element pieces obtained from the adhesive film are peeled off and picked up. The pressure-sensitive adhesive film according to claim 1,
C. (0.degree. C. <A.degree. C. <40.degree. C.), the semiconductor wafer is divided while applying cooling water maintained in the temperature range, and then B.degree. C. to C.degree. B ℃ ≦
A method for dicing a semiconductor wafer, comprising cooling the element to a temperature range of C ° C. ≦ (A-3) ° C., and then peeling and picking up the element pieces from the adhesive film. 4. The relationship between A.degree. C., B.degree. C. and C.degree.
4. The method for dicing a semiconductor wafer according to claim 3, wherein: C.ltoreq.C.degree. C..ltoreq. (A-3) .degree.