JP2000281992A - Sheet for fixing semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject sheet which can prevent the occurrence of chippings at the time of dicing a semiconductor wafer. SOLUTION: A sheet for fixing a semiconductor wafer which comprises a base material in a sheet form and a pressure-sensitive adhesive layer laminated on the base material, wherein a chipping preventive layer is laminated between the base material and the pressure-sensitive adhesive layer. The chipping preventive layer comprises 100 pts.wt. of a base polymer, 10-200 pts.wt. of a heat-polymerizable compound, and 0.1-10 pts.wt. of a heat-polymerization initiator, and has a modulus of 5.0×105-1.0×1011 dyn/cm2 and a thickness of 5-25 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for fixing a semiconductor wafer using a synthetic resin sheet as a base material, and in particular, can prevent chipping (breaking of chips of a semiconductor wafer) when dicing a semiconductor wafer. The present invention relates to a semiconductor wafer fixing sheet capable of improving yield and dicing speed.

[0002]

BACKGROUND OF THE INVENTION The present applicant discloses a semiconductor wafer fixing sheet for preventing chipping in which a primer layer is laminated between a base material and an adhesive layer, and the primer layer has an effect of preventing chipping. (Japanese Patent Application No. 10-8815)
No. 8).

[0003]

However, in this semiconductor wafer fixing sheet, the anchoring property (adhesive strength of the adhesive to the substrate) is improved and the transfer rate of the plasticizer to the polyvinyl chloride substrate is increased. It's a great way to do it,
Looking closely, chipping had occurred during dicing.

Accordingly, an object of the present invention is to provide a semiconductor wafer fixing sheet which does not cause chipping during semiconductor wafer dicing.

[0005]

The present inventors have made intensive studies in view of the above, and as a result, have found that a heat permeable sheet as a base material and a semiconductor wafer fixing adhesive layer having an adhesive layer laminated on the base material are provided. In the sheet, an anti-chipping layer is laminated between the base material and the pressure-sensitive adhesive layer, and the anti-chipping layer is composed of 100 parts by weight of the base polymer, 10 to 200 parts by weight of the heat-polymerizable compound, and 0.1 to 10 parts of the heat-polymerization initiator. And an elastic modulus of the anti-chipping layer of 5.0 × 10 ^{5 to} 1.0 × 1.
It has been found that the above problem can be solved by setting the thickness to 0 ¹¹ dyn / cm ² and the thickness of the anti-chipping layer to 5 to 25 μm, thereby completing the present invention.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the above-mentioned chipping is prevented by providing an anti-chipping layer between a pressure-sensitive adhesive layer and a substrate, and limiting the elastic modulus and layer thickness of the anti-chipping layer. Things.

This anti-chipping layer is made of base polymer 1
00 parts by weight, 10 to 200 parts by weight of a heat-polymerizable compound, and 0.1 to 10 parts by weight of a heat-polymerization initiator. The compounding of the heat-polymerizable compound is to increase the cohesive force of the entire anti-chipping layer by the heated heat-polymerization initiator, and if the compounding ratio is too small, the portion hardened even when heated is reduced. It does not contribute to the improvement of cohesion, and if it is too much, the chipping layer becomes hard, and the chipping prevention layer is broken at the time of bonding, or it cannot be expanded, resulting in poor pickup. Therefore, preferably 10 to 200 parts by weight, more preferably 20 parts by weight -10
0 parts by weight is good. If the modulus of elasticity of the anti-chipping layer is too low, chipping of the back surface, that is, chipping occurs, and if it is too high, the anti-chipping layer becomes hard at the time of bonding with the wafer, and the anti-chipping layer breaks or expands at the time of bonding. 5.0 × 10 ^{5 to} 1.0 × 10 ¹¹ d
yn / cm ² , more preferably 1.0 × 1
0 ⁷ to 1.0 × good ^{10 10} dyn / cm ^2. If the thickness of the anti-chipping layer is too small, the effect of preventing chipping will not be obtained, and if it is too thick, bonding will not be successful. Therefore, the thickness is preferably 5 to 25 μm, more preferably 10 to 20 μm.

The heat-polymerizable compound is formed into a three-dimensional network by a heated heat-polymerization initiator, thereby preventing migration of the plasticizer. A low molecular weight compound having at least two polymerizable carbon-carbon double bonds in a molecule capable of forming a three-dimensional network is preferable, and specifically, an acrylate compound, urethane acrylate, urethane acrylate oligomer and / or monomer, epoxy acrylate , Polyester acrylate urethane and the like. The heat-polymerizable compound is not particularly limited, but preferably has a molecular weight of 300 to 30,000.

The acrylate compound includes, for example, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4 -Butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate and the like.

The urethane acrylate includes, for example, polyester urethane acrylate, polyether urethane acrylate, 4-functional urethane acrylate,
There is a functional urethane acrylate.

The urethane acrylate oligomer is a heat-polymerizable compound having at least two carbon-carbon double bonds, for example, a polyol compound of polyester type or polyether type and a polyvalent isocyanate compound such as ( 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane 4,4-diisocyanate, etc.)
Is reacted with a terminal isocyanate urethane prepolymer to give an acrylate or methacrylate having a hydroxyl group (for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate). , Polyethylene glycol methacrylate, etc.).

The above-mentioned epoxy acrylate is synthesized by reacting an epoxy group with acrylic acid or methacrylic acid, and includes bisphenol A type, bisphenol S type, bisphenol F type, epoxy oil type, and phenol novo. There are rack type, alicyclic type and the like.

The above-mentioned polyester acrylate is obtained by condensing acrylic acid to an OH group remaining on a polyester skeleton synthesized from a diol, a polyol and a dibasic acid to form an acrylate. For example, phthalic anhydride / propylene oxide diol / acrylic Acid, adipic acid / 1,6
-Hexanediol / acrylic acid, trimellitic acid / diethylene glycol / acrylic acid and the like.

In the present invention, the heat polymerization initiator is used to increase the cohesive force of the entire anti-chipping layer by increasing the bonding at the reaction point with the heat polymerizable compound when heated. If the compounding ratio is too small, the curing is slow and the workability is inferior, and if the compounding ratio is too large, unreacted initiator remains and contamination occurs.
10 parts by weight, more preferably 1 to 5 parts by weight.

As the heat polymerization initiator, there are an organic peroxide derivative and an azo polymerization initiator, and the azo polymerization initiator is more preferably an organic peroxide derivative because nitrogen is generated during heating. Specific examples of the heat polymerization initiator include ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate, azobisisobutyronitrile and the like. is there. If necessary, an amine compound such as triethylamine, tetraethylpentamine, or dimethylaminoether may be used in combination as a polymerization accelerator.

The heating is performed simultaneously in the drying step after the application of the anti-chipping layer.

As the pressure-sensitive adhesive for the semiconductor wafer fixing sheet according to the present invention, a conventionally known general-type pressure-sensitive adhesive can be used. Examples of the general-type pressure-sensitive adhesive include acrylic polymers, elastomers, and UV-curable pressure-sensitive adhesives (for example, JP-A-9-3286).
No. 63) and a heat-curable pressure-sensitive adhesive (for example, a pressure-sensitive adhesive described in JP-A-10-25456).

The substrate in the present invention is preferably one that allows heat from the outside of the substrate to reach the anti-chipping layer, for example, polyvinyl chloride, polybutene, polybutadiene, polyurethane, ethylene-vinyl acetate copolymer, polyethylene terephthalate, A single layer, a composite layer, or a plurality of layers of polyethylene, polypropylene, or the like can be employed. Further, a sheet of another material may be laminated on the surface opposite to the surface on which the anti-chipping layer is laminated. The thickness of the base material of the semiconductor wafer fixing sheet is generally 10 to 500 μm.
m.

The sheet for fixing a semiconductor wafer according to the present invention is stored by adhering release paper or a release sheet such as polyethylene laminated paper or release-treated plastic film on an adhesive as required.

According to the present invention, in a sheet for fixing a semiconductor wafer having an ultraviolet ray transmitting sheet as a substrate and an adhesive layer laminated on the substrate, chipping is performed between the substrate and the adhesive layer. An anti-chipping layer is laminated, and the anti-chipping layer is 100 parts by weight of the base polymer, and the ultraviolet curable compound 10
200 parts by weight and 0.1 to 10 parts by weight of an ultraviolet curing initiator, and the elastic modulus of the anti-chipping layer is 5.0 × 10 ⁵
１．０1.0 × 10 ¹¹ dyn / cm ^2, and the thickness of the anti-chipping layer is 5 to 25 μm, so that fine chipping does not occur.

[0021]

EXAMPLES Examples of the semiconductor wafer fixing sheet according to the present invention will be described in detail with reference to Table 1 while comparing them with comparative examples.

The semiconductor wafer fixing sheet according to each of the examples and the comparative examples includes a sheet substrate made of polyvinyl chloride having a thickness of 70 μm, an anti-chipping layer laminated on the substrate, and an anti-chipping layer. 10 μm thickness laminated on the layer
Of the general acrylic pressure-sensitive adhesive. Here, the anti-chipping layer contains 100 parts by weight of polyacryl as a base polymer in addition to the heat-polymerizable compound and the heat-polymerization initiator shown in Table 1. The heat-polymerizable compound in Table 1 employs a hexafunctional urethane acrylate oligomer, and the heat polymerization initiator employs peroxy dicarbonate. The numbers in the heat-polymerizable compound and the heat-polymerization initiator in Table 1 are parts by weight, and the heating amount after dicing is 100 ° C. × 10 minutes.

[0023]

[Table 1]

The "elastic modulus" in Table 1 indicates the ambient temperature 23
The temperature was measured with a measuring instrument RDA-II (Rheometrics) under the conditions of a temperature of 1 ° C. and a frequency of 1 Hz, and “chipping property” was measured 20 minutes after a 400 μm-thick silicon wafer was pasted on a semiconductor fixing sheet. 3.8mm × 7.
The chip, which was fully cut into a 0 mm square chip, was observed under a microscope of 200 times magnification, and 15 μm was added to all 30 randomly extracted samples.
When there was no chip having a size of m or more, it was evaluated as ○, and when it was not, evaluated as ×. The “expandability” was evaluated as “good” when the chip interval on the sheet was expanded as initially set when stretched by 50%, and as “x” when the chip interval was not so.
When the back surface of the picked-up chip was observed with a 200 × microscope, no adhesive was found when the adhesive was found, and × when the adhesive was found.

In Comparative Example 1 in which the amount of the heat-polymerizable compound in the anti-chipping layer was small, the composition became too soft and had a problem in chipping property, and in Comparative Example 2 in which the content was increased, it was too hard and there was a problem in expandability.

Comparative Example 3 containing a small amount of the heat polymerization initiator was too soft and had a problem in chipping property, and Comparative Example 4 containing a large amount of the heat polymerizable compound had a problem in contamination.

In Comparative Example 5 in which the thickness of the anti-chipping layer was reduced, there was a problem in chipping properties, and in Comparative Example 6 in which the thickness was 50 μm (not shown in the table), there was a problem in bonding.

If the elastic modulus is too low, there is a problem in the expandability (see Comparative Example 2), and if the elastic modulus is too high, there is a problem in the chipping property (see Comparative Example 5).

[0029]

The semiconductor wafer fixing sheet according to the present invention comprises a heat permeable sheet as a base material and a semiconductor wafer fixing sheet having an adhesive layer laminated on the base material. An anti-chipping layer between the agent layers, wherein the anti-chipping layer is 100 parts by weight of the base polymer;
The composition is provided with 10 to 200 parts by weight of the heat-polymerizable compound and 0.1 to 10 parts by weight of the heat-polymerization initiator, and the elasticity of the anti-chipping layer is set to 5.0 × 10 ^{5 to} 1.0 × 10 ¹¹ dyn / cm ^2. The thickness of the anti-chipping layer is set to 5 to 25 μm, so that chipping does not occur during dicing.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeru Wada 2-3-1-1, Kamakura-shi, Kanagawa Prefecture Inside Toyo Kagaku Co., Ltd. (72) Inventor Masashi Kume 2-3-1-1, Kamakura-shi, Kanagawa Toyo F-term in Chemical Co., Ltd. (reference) 4J004 AA05 AA10 AB01 AB07 CA05 CC02 CC04 CD05 CD06 DA02 DB02 FA05 FA08

Claims (1)

[Claims] 1. A semiconductor wafer fixing sheet having a sheet-like substrate and an adhesive layer laminated on the substrate, wherein an anti-chipping layer is laminated between the substrate and the adhesive layer. 100 parts by weight of the base polymer,
The composition is provided with 10 to 200 parts by weight of the heat-polymerizable compound and 0.1 to 10 parts by weight of the heat-polymerization initiator, and the elasticity of the anti-chipping layer is set to 5.0 × 10 ^{5 to} 1.0 × 10 ¹¹ dyn / cm ^2. A semiconductor wafer fixing sheet wherein the thickness of the anti-chipping layer is 5 to 25 μm.