JP3290471B2 - Wafer processing tape and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape for processing a wafer. Wafer processing tapes are used in a semiconductor integrated circuit (hereinafter referred to as IC) manufacturing process.

[0002]

2. Description of the Related Art In general, an IC is formed by slicing a high-purity silicon single crystal or the like into a semiconductor wafer (hereinafter sometimes abbreviated simply as a wafer) and then diffusing the surface of the semiconductor wafer by means such as impurity diffusion or ultra-fine processing. It is manufactured by a method of incorporating an integrated circuit, dicing and chipping.

In each of these steps, a tape for processing a wafer is used on the wafer surface in order to prevent damage or breakage of the surface pattern of the wafer.

Generally, an aqueous emulsion adhesive and a solvent-based adhesive are used as the adhesive.
From the viewpoint of hygiene and cost, an aqueous emulsion pressure-sensitive adhesive is preferred.

In addition, when a film using a solvent-based adhesive is used when a film for wafer processing is used for wafer processing and then washed to remove deposits on the surface of the wafer, contamination with water cleaning may occur. Can not be completely removed, it takes time and labor to use an organic solvent, etc., and there is also a problem in terms of safety and hygiene.
On the other hand, in a film using an aqueous emulsion adhesive,
Even water washing can sufficiently remove contamination.

[0006] However, the water-based emulsion pressure-sensitive adhesive has a disadvantage that its water resistance is inferior to that of the solvent-based pressure-sensitive adhesive. As a wafer processing tape which solves this drawback, a wafer processing tape using an acrylic resin emulsion pressure-sensitive adhesive obtained by adding a fluorine-containing monomer to a monomer of a pressure-sensitive adhesive material and polymerizing the same has been developed.

However, since the fluorine-containing monomer has water repellency and oil repellency, it has poor compatibility with other monomers, and requires a large amount of a surfactant to mix these monomers. . The adhesive obtained by polymerization is
On the contrary, the water resistance is deteriorated, and the surfactant bleeds on the surface, and if the surfactant is peeled off after being attached to the wafer, the surface of the wafer is contaminated.

[0008]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a wafer processing tape which does not contaminate a wafer and has excellent water resistance.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, when a fluorine-containing monomer is added to a monomer of a pressure-sensitive adhesive material for polymerization, a reactive surfactant is used. When used, the bond with the emulsion particles is a physical bond, the separation of the fluorine-containing monomer and other monomers does not occur, and the added amount can be polymerized in a smaller amount than that of the non-reactive surfactant, and is obtained by polymerization. The present inventors have found that a wafer processing tape obtained by applying the obtained acrylic resin emulsion pressure-sensitive adhesive composition to a base film does not contaminate the wafer and has excellent water resistance, and thus completed the present invention.

That is, according to the present invention, 0.1 to 5.0 parts by weight of a reactive surfactant is added to 100 parts by weight of a monomer mixture containing 3.0 to 20.0% by weight of a fluorine-containing monomer to carry out polymerization. An acrylic resin emulsion pressure-sensitive adhesive, and then applying the acrylic resin emulsion pressure-sensitive adhesive to a substrate film.

Further, the present invention is a method of grinding the back surface of a wafer, characterized by using the tape for processing a wafer.

The monomer mixture includes (meth) acrylate monomers such as methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate, and acrylic acid, methacrylic acid, which is a carboxylic acid-containing vinyl compound. It is a mixture of a monomer such as crotonic acid, maleic acid, fumaric acid, and itaconic acid, and a fluorine-containing monomer.

The fluorine-containing monomer is a fluorine-containing vinyl compound. Examples thereof include trifluoroethyl acrylate, trifluoroethyl methacrylate, heptadecafluorodecyl acrylate, and heptadecafluorodecyl methacrylate.

The fluorine-containing monomer in the monomer mixture is 3.0 to 20.0% by weight. More preferably, it is 5.0 to 10.0% by weight. If it is less than 3.0% by weight, the water resistance will not be improved, and if it exceeds 20.0% by weight, the compatibility with other monomers will be poor and copolymerization will not be performed well.

The reactive surfactant at the time of polymerization used in the present invention can be appropriately selected as long as it has a vinyl group in the molecule, and is preferably a nonionic surfactant or an anionic surfactant which is an ammonium salt. It is a surfactant.

For example, as the nonionic surfactant, a compound obtained by adding an allyl group to a benzene ring of polyoxyethylene alkyl phenyl ether, and as the anionic surfactant, polyoxyethylene alkyl phenyl ether sulfate is used. Compounds obtained by adding an allyl group to the benzene ring of a chloride, compounds obtained by adding a sulfate to a compound obtained by adding a higher alcohol and an allyl group to maleic acid, and the like.

However, in the case of anionic surfactants of soda salt and potassium salt, sodium ions and potassium ions remaining in the adhesive may cause corrosion of the wafer.

The addition amount of the reactive surfactant is 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, based on 100 parts by weight of the monomer mixture. . If the amount is less than 0.1 part by weight, the stability during polymerization is poor, many aggregates are generated, and the yield is poor. 5 . If the amount exceeds 0 parts by weight, the resulting pressure-sensitive adhesive film absorbs water, resulting in poor water resistance.

The acrylic resin emulsion adhesive is an adhesive obtained by adding a reactive surfactant, deionized water, and a polymerization initiator to a monomer mixture and emulsion-polymerizing the resulting mixture in water. It can be performed appropriately according to the force. The acrylic resin emulsion adhesive thus polymerized usually contains 30 to 60 wt.
% Solid content (acrylic resin), but can be further diluted with water for viscosity adjustment at the time of coating.

If necessary, a crosslinking agent such as an epoxy resin may be added to the acrylic resin emulsion pressure-sensitive adhesive.

As the base film used in the present invention, a film made of synthetic resin or natural or synthetic rubber can be appropriately selected.

Examples of the material of the base film include ethylene-vinyl acetate copolymer, polybutadiene,
Soft vinyl chloride resin, polyolefin, polyester,
Thermoplastic elastomers such as polyamides, and synthetic rubbers such as diene, nitrile, silicone, and acrylic rubbers.

As a method for applying the acrylic resin emulsion pressure-sensitive adhesive compounding liquid to the base film, a known coating method such as a reverse roll coater, a gravure coater, a bar coater, a die coater, a comma coater, etc. is used. This is possible by drying with hot air at 150 ° C. The coating thickness after drying is usually 1 μm to 100
It is about μm.

It is preferable to attach a synthetic resin film called a separator to the pressure-sensitive adhesive layer side in order to protect the pressure-sensitive adhesive layer if necessary.

The method of grinding the back surface of the wafer is not particularly limited, and a known method may be appropriately used for physical grinding using a grinder or the like or chemical grinding using chemical etching or the like.

[0026]

The present invention will be described more specifically with reference to the following examples. Example 1 150.0 parts by weight of deionized water was added to a flask equipped with a thermometer, a reflux condenser, a dropping funnel, a nitrogen inlet, and a stirrer.
As a reactive surfactant, 3.0 parts by weight of a compound obtained by adding an allyl group to a benzene ring of polyoxyethylene nonylphenyl ether (ethylene oxide 20 mol) was added, and the mixture was heated to 70 ° C. while stirring under a nitrogen atmosphere. Thereafter, 0.5 parts by weight of ammonium persulfate (polymerization initiator) is added and dissolved. Then, methyl methacrylate 2
2.5 parts by weight, 2-ethylhexyl acrylate
A monomer mixture consisting of 5 parts by weight, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid, and 10.0 parts by weight of trifluoroethyl acrylate was continuously added dropwise for 4 hours, and stirring was continued for 3 hours after completion of the addition. Polymerization was continued to obtain an acrylic resin emulsion pressure-sensitive adhesive having a solid content of about 40% by weight.

[0027] EV obtained by forming a film of this compounded liquid by the T-die method.
A 110 μm thick film composed of two layers, A and PP, was applied to the corona-treated EVA surface with a roll coater,
After drying at 0 ° C., a wafer processing tape having an acrylic resin emulsion pressure-sensitive adhesive layer having a coating thickness of 30 μm was obtained.

The wafer processing tape obtained in this way is JIS
Attached to a SUS plate having irregularities of 30 μm at the maximum height at a reference length of 0.8 mm defined in B0601,
It was immersed in water and evaluated for water resistance. This reference length is
This is the reference measurement length of the sample when measuring the roughness of the surface of the measured object.

The evaluation method is as follows. The SUS plate to which the tape for wafer processing is adhered is immersed in water for 10 minutes, and the SUS plate is evaluated based on the infiltration area of water, and the ratio of the infiltration area to the total area of the SUS plate is expressed as a percentage. Indicated. The size of the SUS plate is 5 cm in width, 20 cm in length, and 100 cm ² in area.

Further, a water drop was dropped on the surface of the pressure-sensitive adhesive of the tape for wafer processing, and the contact angle was measured. The greater the water repellency, the greater the contact angle.

Further, the wafer processing tape is
An automatic tape peeling machine ("ATRM-2000B" manufactured by Takatori Co., Ltd.) is attached to an inch semiconductor wafer by using an automatic tape pasting machine ("ATM-1000B" manufactured by Takatori Co., Ltd.) and left at room temperature for one day. The wafer processing tape is peeled off by using the same, and the obtained 4-inch semiconductor wafer is subjected to a surface inspection apparatus HLD-3 manufactured by Hitachi Electronics Engineering Co., Ltd.
The degree of contamination of the wafer was measured based on the number of foreign particles having a size of 0.2 μm or more according to 00B. As shown in Table 1, the water resistance was good and the wafer was free from contamination.

Example 2 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 70.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid and 3.0 parts by weight of heptadecafluorodecyl acrylate was added. Example 1 was repeated except that 0.1 part by weight of a compound obtained by adding an allyl group to the benzene ring of an ammonium salt of ethylene nonylphenyl ether sulfate (ethylene oxide 10 mol) was used. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1. The wafer processing tape thus obtained was evaluated in the same manner as in Example 1.
The results were good as shown in [Table 1].

Example 3 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
100 parts by weight of a monomer mixture consisting of 53.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid, and 20.0 parts by weight of heptadecafluorodecyl methacrylate are added, and a reactive surfactant is added. As ammonium salt of polyoxyethylene nonyl phenyl ether sulfate (ethylene oxide 1
0 mol) of a compound obtained by adding an allyl group to a benzene ring in an amount of 5.0 parts by weight. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1. The tape for wafer processing thus obtained was used in Example 1.
Was evaluated in the same way as The results were good as shown in [Table 1].

Comparative Example 1 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
Ammonium salt of polyoxyethylene nonyl phenyl ether sulfate as a reactive surfactant using 100 parts by weight of a monomer mixture consisting of 73.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, and 2.0 parts by weight of methacrylic acid (Ethylene oxide 10 mol) Compound 3.0 in which an allyl group is added to the benzene ring
Same as Example 1 except that parts by weight were used. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1. The wafer processing tape thus obtained was evaluated in the same manner as in Example 1. The result was poor water resistance as shown in [Table 1].

Comparative Example 2 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 68.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid and 5.0 parts by weight of trifluorodecyl acrylate was added, and polyoxyethylene nonylphenyl was used as a surfactant. Polymerization was carried out in the same manner as in Example 1 except that 5.0 parts by weight of ether (10 mol of ethylene oxide) was used, but polymerization was not possible due to poor compatibility of the monomers. Comparative Example 3 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 68.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid and 5.0 parts by weight of heptadecafluorodecyl acrylate was added, and polyoxyethylene nonyl was used as a surfactant. Same as Example 1 except that 10.0 parts by weight of ammonium salt of phenyl ether sulfate (10 mol of ethylene oxide) was used. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1.
The wafer processing tape thus obtained was evaluated in the same manner as in Example 1. The result was poor water resistance as shown in [Table 1].

Comparative Example 4 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 43.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid, and 30.0 parts by weight of heptadecafluorodecyl methacrylate was added. Polymerization was carried out in the same manner as in Example 1 except that 5.0 parts by weight of a compound having an allyl group added to the benzene ring of ethylene nonyl phenyl ether (20 mol of ethylene oxide) was used. Did not.

Comparative Example 5 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 70.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid, and 3.0 parts by weight of heptadecafluorodecyl methacrylate was added. Polymerization was carried out in the same manner as in Example 1 except that 0.05 parts by weight of a compound obtained by adding an allyl group to the benzene ring of ammonium salt of ethylene nonyl phenyl ether sulfate (ethylene oxide 10 mol) was used. Was not good and could not be polymerized.

Comparative Example 6 22.5 parts by weight of methyl methacrylate, acrylic acid-2-
A monomer mixture consisting of 63.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid and 10.0 parts by weight of heptadecafluorodecyl acrylate was added. Example 1 was repeated except that 10.0 parts by weight of a compound in which an allyl group was added to the benzene ring of ethylene nonylphenyl ether (20 mol of ethylene oxide) was used. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1. The wafer processing tape thus obtained was evaluated in the same manner as in Example 1. The result was poor water resistance as shown in [Table 1].

Comparative Example 7 Methyl methacrylate 22.5 parts by weight, acrylic acid-2-
A monomer mixture consisting of 72.5 parts by weight of ethylhexyl, 2.0 parts by weight of glycidyl methacrylate, 2.0 parts by weight of methacrylic acid, and 1.0 part by weight of heptadecafluorodecyl acrylate was added. Example 1 was repeated except that 0.5 part by weight of a compound obtained by adding an allyl group to the benzene ring of an ammonium salt of ethylene nonylphenyl ether sulfate (ethylene oxide 10 mol) was used. Using this liquid mixture, a tape for processing a wafer was obtained in the same manner as in Example 1. The wafer processing tape thus obtained was evaluated in the same manner as in Example 1.
The result was poor water resistance as shown in [Table 1].

[0040]

[Table 1]

[0041]

By using an acrylic resin emulsion pressure-sensitive adhesive obtained by polymerizing a monomer mixture containing a fluorine-containing monomer with a reactive surfactant, the wafer processing tape has excellent water resistance and does not contaminate the wafer.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-186832 (JP, A) JP-A-3-35011 (JP, A) JP-A-61-141713 (JP, A) JP-A-59-1986 59764 (JP, A) JP-A-4-46979 (JP, A) JP-A-63-296222 (JP, A) JP-A-62-101678 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) H01L 21/301 H01L 21/304 C09J 7/02

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein the fluorine-containing monomer is 3.0 to 20.0.
0.1 to 5.0 parts by weight of a reactive surfactant is added to 100 parts by weight of the monomer mixture, which is 100% by weight, and polymerized to form an acrylic resin emulsion pressure-sensitive adhesive. Wafer processing tape characterized by being applied to a material film. 2. A wafer backside grinding method using the wafer processing tape according to claim 1.