JP3012060B2 - Adhesive tape for fixing semiconductor wafers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape used in a process for manufacturing various semiconductors. More specifically, for example, a wafer on which a pattern is formed is cut into individual patterns and divided into semiconductor elements. The present invention relates to a radiation-curable pressure-sensitive adhesive tape for fixing a semiconductor wafer used at the time.

[0002]

2. Description of the Related Art Conventionally, a pickup method using a radiation-curable pressure-sensitive adhesive tape has been proposed for performing a dicing process for cutting and separating a semiconductor wafer on which a circuit pattern is formed into element pieces.

This is radiation, for example light such as ultraviolet light,
Or a method using a pressure-sensitive adhesive tape for fixing a semiconductor wafer comprising a base film that transmits ionizing radiation such as an electron beam, and a pressure-sensitive adhesive layer coated on the base film and having a property of being cured by irradiation with radiation. It is. More specifically, the element fixing adhesive force at the time of dicing processing is made to be a strong adhesive force, and after cutting and separating the semiconductor wafer into element pieces, irradiation is performed from the base film side to cure the radiation-curable adhesive layer, This is a method in which the element fixing adhesive force is greatly reduced so that a large element of, for example, 25 mm ² or more can be easily picked up regardless of the size of the element piece.

In this method, a radiation-curable compound contained in a pressure-sensitive adhesive layer of a pressure-sensitive adhesive tape for fixing a semiconductor wafer, in which a radiation-curable pressure-sensitive adhesive is coated on a radiation-transparent substrate film, is cured by irradiation with radiation to form an adhesive. It is based on the principle that a three-dimensional network structure is given to the agent to significantly reduce its fluidity and adhesive strength.

However, in such an adhesive tape, the adhesive is cured by a curing reaction of a radiation-curable compound to give a three-dimensional network structure and reduce the adhesive strength. As a result, the shape elasticity is almost lost during pickup. For this reason, it may not be possible to enlarge the element gap by the conventional radial stretching of the adhesive tape.

[0006] In order to solve this problem, the use of flexible polyvinyl chloride (PVC) as the center layer of the base film has already been put into practical use. In some cases, chlorine ions, metal ions, plasticizers, etc. migrate to cause contamination of the surface of the semiconductor wafer due to the inclusion of such stabilizers and plasticizers.

Therefore, as disclosed in JP-A-2-215528, a thermoplastic resin having rubbery elasticity, for example, polybutene-1, polyurethane, polyester elastomer, 1,2-polybutadiene, styrene-isoprene-styrene copolymer. Adhesive tapes have been proposed in which a base film is a laminated film having a central layer of a combined hydrogenated product or styrene-ethylene-butene-styrene copolymer (SEBS). However, these adhesive tapes also require the necking of the base film itself (film stretching) in order to obtain a large and uniform gap amount of element pieces required in a pickup device with image recognition even after stretching after irradiation of radiation. In some cases, partial elongation occurs due to poor force transmission), and rubber-like elasticity is lost due to deterioration of the base film due to irradiation, and the properties are still insufficient.

When polyamide is used as the base film, the base film causes necking.
When the adhesive tape is stretched, there is a problem that the interval between the element pieces does not increase. In addition, since the absolute elongation is small, it breaks when stretched at a high rate . High absolute elongation and high elongation
There is also polyamide, but the problem of necking is not solved ,
It is not suitable because the interval between the element pieces when the adhesive tape is stretched tends to be narrowed.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive tape for fixing a semiconductor wafer which has solved the above-mentioned problems. That is, an object of the present invention is to provide a pressure-sensitive adhesive tape for fixing a semiconductor wafer, which can be stretched without necking or breaking the pressure-sensitive adhesive tape after irradiation, so that the element gap can be significantly increased. I do.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, a base film having a polyamide-polyether copolymer film layer as a central layer has been developed. It has been found that the gap between the elements at the time of stretching can be greatly increased, and that there is no breakage.
The present invention has been accomplished based on this finding.

That is, the present invention provides an adhesive tape for fixing a semiconductor wafer having a radiation-curable adhesive layer provided on one side of a substrate film, wherein the substrate film has a polyamide-polyether copolymer film in a central layer. Having layers,
An adhesive tape for fixing a semiconductor wafer, which is a laminated film having an adhesive coating layer on the radiation-curable adhesive layer side and an anti-transfer layer on the other side via an adhesive layer or directly to this layer. Is provided. Here, the radiation refers to a light beam such as an ultraviolet ray or an ionizing radiation such as an electron beam.

The polyamide-polyether copolymer used in the present invention includes, in addition to a graft copolymer or a block copolymer, an alloy of polyamide and polyether,
It also includes mixed forms such as N. The elongation is preferably 150% or more.

The polyamide used in the present invention is a lactam represented by nylon 6 (polycapramide), nylon 11 (polyundecanamide), nylon 12 (polydodecanamide) or a homopolymer mainly containing ω-aminocarboxylic acid. Diamines and dicarboxylic acids represented by polyamides, copolyamides, nylon 6,6 (polyhexamethylene adipamide), nylon 6,10 (polyhexamethylene sebacamide), nylon 6,12 ( polyhexamethylene capramide), etc. And homopolyamides and copolyamides containing as a main component. At the same time, polyether amides and polyester amides, which are copolymers of amide monomers and monomers other than amide monomers, are also included.

The polyether used in the present invention means a polymer of a diol such as polyethylene glycol, polypropylene glycol, polybutylene glycol and polytetramethylene glycol.

In the polymerization of the polyamide-polyether copolymer of the present invention, one or more dicarboxylic acids such as dodecane diacid, terephthalic acid, isophthalic acid, etc. may be used in addition to the polyamide component and the polyether component. It may be added. The polyamide-polyether copolymer used in the present invention may contain ordinary additives such as heat stabilizers and lubricants.

Modified products obtained by adding or substituting low molecular compounds such as maleic acid containing a functional group such as a carboxyl group to the above copolymers as required, and modified products, and mixtures of the above copolymers with general-purpose resins such as polyolefins. Conventionally known ones, or a mixture thereof can be used, and the type and mixing ratio of the resin can be arbitrarily selected according to various conditions such as required characteristics of the base film and cost. Further, a blend film composed of a composition obtained by mixing another resin with the polyamide-polyether copolymer of the present invention can be used as the center layer.

The resin for a blend film with the polyamide-polyether copolymer of the present invention is not particularly limited except that it is a resin compatible with the polyamide-polyether copolymer. It is preferable to have flexibility in radiation transmission and low density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polymethylpentene, ethylene-ethyl acrylate copolymer Copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ionomer, ethylene-propylene-diene copolymer, etc. Known polymers such as homopolymers and copolymers of Objects, or other resin and requirements of the substrate film include mixtures of the elastomer, the type of resin in accordance with the circumstances such as cost, it is possible to arbitrarily select the blending ratio at 50 wt% or less. In addition,
It is preferable to blend a resin having excellent adhesiveness with the pressure-sensitive adhesive applied layer and the transfer prevention layer, since delamination hardly occurs when the pressure-sensitive adhesive tape is stretched.

As a mixing means for preparing the resin of the present invention, a heating roll, a Banbury mixer and the like are generally employed. The use of the mixing means as described above makes mixing easy and reliable, so that the obtained base film also has the effect that there is no whitening phenomenon even when bent.
Further, a multilayer film of the polyamide-polyether copolymer film of the present invention and a film made of another resin can be used as the central layer.

The resin for the film to be laminated on the single film or the blend film of the polyamide-polyether copolymer of the present invention is not particularly limited, but it is preferable that the resin has radiation transparency and flexibility. For example, a resin for a blend film that is compatible with a polyamide-polyether-based copolymer, a resin that is hardly compatible but satisfies requirements, such as a conventionally known resin, or a mixture thereof, or a laminated film of these, or another Mixtures with resins and elastomers, etc. are listed, depending on the required properties of the base film, processability, cost and other circumstances, the type of resin, the thickness of the polyamide-polyether copolymer film or less, the radiation-curable adhesive layer The side film can be arbitrarily selected.

It is preferable to laminate a polyamide-polyether copolymer and a resin having excellent adhesiveness with the adhesive coating layer or the transfer prevention layer since delamination hardly occurs when the adhesive tape is stretched.

As a method for producing the multilayer film, a conventionally known co-extrusion method, lamination method, or the like is used. At this time, as is usually performed in the production of a normal laminated film, an adhesive between the multilayer films is used. May be applied. As such an adhesive, a conventionally known adhesive such as an ethylene-vinyl acetate copolymer or a maleic acid-modified ethylene-vinyl acetate copolymer can be used.

The resin for the pressure-sensitive adhesive coating layer on the side to be coated with the radiation-curable pressure-sensitive adhesive used in the present invention is radiation-transparent, hardly contaminates the Si wafer, and has an adhesive force with the radiation-curable pressure-sensitive adhesive. Larger ones, for example, ethylene-based ones are preferable, and low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene -Methacrylic acid copolymer, ethylene-acrylic acid copolymer, etc., conventionally known ones, and mixtures thereof, and the like, which can be arbitrarily selected depending on the adhesiveness to the radiation-curable pressure-sensitive adhesive used. . This pressure-sensitive adhesive coating layer serves to strengthen the adhesion between the pressure-sensitive adhesive and the substrate film, and prevents contamination of the semiconductor wafer due to peeling of the pressure-sensitive adhesive from the substrate film when the pressure-sensitive adhesive tape is stretched after wafer processing. To contribute.

The resin for the transfer prevention layer used in the present invention is preferably, for example, an ethylene resin, and is preferably a low-density polyethylene, a linear low-density polyethylene, an ethylene-vinyl acetate copolymer, or an ethylene-methyl methacrylate copolymer. A conventionally known polymer such as a polymer, an ethylene-ethyl methacrylate copolymer, an ethylene-methacrylic acid copolymer, an ethylene-acrylic acid copolymer, or a mixture thereof may be used. This anti-transfer layer does not hinder the elongation characteristics of the pressure-sensitive adhesive tape and is intended to prevent blocking of the base film.

In order to reduce friction between the adhesive tape and the jig during stretching of the adhesive tape and prevent necking of the base film, a low-density polyethylene, an ethylene-vinyl acetate copolymer, and It is preferable to use an ethylene-vinyl acetate copolymer having a vinyl acetate content of 5% by weight or less as the vinyl acetate copolymer.

As a method of laminating the center layer and the pressure-sensitive adhesive coating layer or the transfer prevention layer, a known method such as a co-extrusion method, heat fusion or lamination method with an adhesive is used. Examples of the adhesive in the case of laminating using an adhesive include an ethylene-vinyl acetate copolymer, a maleic acid-modified ethylene-vinyl acetate copolymer, a maleic acid-modified ethylene-α-olefin copolymer, a copolymerized polyester resin, and the like. Adhesive compounds, or mixtures thereof.

The ethylene-vinyl acetate copolymer used as an adhesive or the maleic acid-modified copolymer of this copolymer is preferably one having a vinyl acetate content of 20% by weight or more, since it has a large adhesive strength and hardly causes delamination. Known methods such as a coextrusion method and a lamination method are used for the production of the laminated film.

The thickness of the substrate film is usually preferably from 30 to 300 μm from the viewpoints of strong elongation characteristics and radiation transparency. The thickness ratio of the center layer of the base film is arbitrarily set according to the required characteristics of the base film, but is usually preferably 30% or more with respect to the total thickness of the base film.
% Is more preferable, and the provision of both the pressure-sensitive adhesive coating layer and the transfer prevention layer provides a symmetrical structure of the base film in addition to the above, so that the end of the base film is provided. Does not curl on either side,
There is also the advantage of being operationally favorable.

The surface of the base material film on the transfer prevention layer side is subjected to graining or lubricant coating to prevent blocking, and to prevent necking of the base material film by reducing friction between the adhesive tape and the jig when the adhesive tape is stretched. effective.

As the radiation-curable pressure-sensitive adhesive, a conventionally known pressure-sensitive adhesive is used. At least one selected from the group consisting of a cyanurate compound and an isocyanurate compound having a carbon-carbon double bond per 100 parts by weight of an acrylic pressure-sensitive adhesive is used. When using an adhesive containing 10 to 200 parts by weight of one kind of compound and 5 to 100 parts by weight of a linear polyester or polyol urethane acrylate compound having two carbon-carbon double bonds, an adhesive after irradiation with radiation Since the rubbery elasticity of the layer can be maintained, the effect of maintaining the rubbery elasticity (flexibility) of the pressure-sensitive adhesive tape after irradiation is particularly large.

When the adhesive tape for fixing a semiconductor wafer of the present invention is cured by ultraviolet irradiation, a photopolymerization initiator such as isopropylbenzoin ether, isobutyl benzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, dodecylthioxanthone, dimethylthioxanthone is used. , Diethylthioxanthone, benzyl dimethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenyl propane, etc. added to the pressure-sensitive adhesive layer allows the curing reaction to proceed efficiently even if the curing reaction time or the amount of ultraviolet irradiation is small, and the element is fixed. Adhesive strength can be reduced.

Further, if necessary, the surface of a radiation-curable silicon acrylate or silicon methacrylate or a semiconductor wafer as an adherend is coated with a metal substance in order to properly reduce the adhesive strength of fixing the element after irradiation. In order to similarly reduce the adhesive strength for fixing the element to the specially treated surface, an ion sequestering agent, etc., and a tackifier, an adhesion regulator, a surfactant, etc., or other modifiers and conventional components should be blended. Can be. The thickness of the radiation-curable pressure-sensitive adhesive layer is usually 2 to 50 μm.

[0032]

Next, the present invention will be described in more detail with reference to examples. In the following examples, each characteristic was tested and evaluated as follows.

1) Adhesive Force (g / 25 mm) The magnitude of the element-fixed adhesive force before irradiation and the degree of decrease after irradiation were examined. A 5-inch diameter Si wafer was used as an adherend on the radiation-curable pressure-sensitive adhesive tape thus prepared, and JIS-Z0
The adhesive force before and after ultraviolet irradiation was measured based on 237 (9).
0 ° peeling, peeling speed 50 mm / min). At this time, the surface state of the wafer bonded to the adhesive tape was a mirror surface state.

2) Element gap (μm) The size of the element gap and the degree of uniformity in the vertical and horizontal directions when the adhesive tape was stretched were examined. A 5-inch diameter Si wafer fixed to the prepared radiation-curable adhesive tape was fully cut into a size of 3 × 3 mm with a dicing saw, cured by ultraviolet irradiation, and then expanded with a wafer expansion device (air pressure 2.0 kg / c).
In m), the length of the element gap in the vertical and horizontal directions when the expanded stroke was raised by 10 mm and stretched was measured, and the size and uniformity of the element gap were observed. Here, the element gap amount is
Including the blade thickness of 40 μm during dicing.

3) Strength of Expanding Adhesive Tape The state of the tape at an expanding stroke of 30 mm was examined. Full cut into a size of 3 × 3 mm in the same manner as in the method 2), and the expand stroke is 30 mm.
The state of whether or not the pressure-sensitive adhesive tape when it was raised and stretched was broken was examined.

Examples 1 to 6 and Comparative Examples 1 to 4 Using the extruder, a base film having each of the layers shown in Tables 1 and 2 was used as a resin A to E alone or in a kneaded blend composition. By using (co) extrusion processing. The thickness of each of the obtained base films (consisting of the pressure-sensitive adhesive applied layer, the center layer, and the transfer prevention layer) is 100 μm. The obtained base film is subjected to a corona treatment on the side of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer after drying has a thickness of 10 μm.
An adhesive was applied so as to obtain a radiation-curable adhesive tape.

The resins and adhesives used are shown below. Resin A (polyamide-polyether copolymer): Pebax 3533SNOO manufactured by Toray Resin B (polyamide-polyether copolymer): Daiamide PAE 47MS1 EPR (ethylene-propylene-diene copolymer) manufactured by Daicel Chemical: Nippon Gosei Rubber EP 51 resin C (polyamide): Daiamide manufactured by Daicel Chemical
L1940 Resin D (polyamide): Aramid CM104 manufactured by Toray
1 Resin E (polybutene-1) EVA-10 (ethylene-vinyl acetate copolymer (vinyl acetate content 10%)): Evatate H2 manufactured by Sumitomo Chemical Co., Ltd.
021F EVA-3 (ethylene-vinyl acetate copolymer (vinyl acetate content 3%)): Yucalon-Eva V11 manufactured by Mitsubishi Yuka
3K LLDPE (linear low-density polyethylene): Tosoh Petrocene 205 Adhesive A: Acrylic adhesive 100 parts by weight Isocyanurate compound 80 parts by weight Urethane acrylate compound 20 parts by weight Photopolymerization initiator 1 part by weight Adhesive B: acrylic Adhesive 100 parts by weight Cyanurate compound 40 parts by weight Urethane acrylate compound 10 parts by weight

[0038]

When the adhesive tape for fixing a semiconductor of the present invention is used for cutting a semiconductor wafer or the like, the adhesive tape after irradiation can be stretched without necking or breaking the adhesive tape. Large expansion can be performed. Therefore, the image recognition of the element piece becomes easy. Therefore, there is an excellent effect that the element can be picked up easily and without damage.

[Table 1]

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Ishiwatari 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Inventor Kazushige Iwamoto 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Morikuni Hasebe 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (56) References JP-A-5-148457 (JP, A) JP-A Sho 63-17980 (JP, A) JP-A-5-28828 (JP, A) JP-A-4-270760 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 7/02 H01L 21/301 H01L 21/68

Claims (1)

(57) [Claims] 1. A pressure-sensitive adhesive tape for fixing a semiconductor wafer having a radiation-curable pressure-sensitive adhesive layer provided on one side of a substrate film, wherein the substrate film has a polyamide-polyether copolymer film in a central layer as a layer structure. A semiconductor film having a layer, an adhesive coating layer on the side of the radiation-curable pressure-sensitive adhesive layer, or an adhesive coating layer on the side of the radiation-curable pressure-sensitive adhesive layer, and a transfer prevention layer on the other side. Adhesive tape for wafer fixing.