JP2983729B2 - 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 when performing dicing 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, there has been a problem that the element gap cannot be enlarged by the conventional radial stretching of the adhesive tape.

[0006] In order to solve this problem, a material in which soft polyvinyl chloride (PVC) is used as a central layer of a base film has already been put into practical use. Due to the contained stabilizer and plasticizer, chloride ions, metal ions, plasticizer, and the like may migrate and cause contamination of the surface of the semiconductor wafer.

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. A pressure-sensitive adhesive tape has been proposed in which a laminated film having a central layer of a hydrogenated product of a union, styrene-ethylene-butene-styrene copolymer (SEBS) is used as a base film. However, these pressure-sensitive adhesive tapes may partially delaminate during stretching or may be difficult to peel off the element pieces from the pressure-sensitive adhesive tape when picking up the element pieces, which may cause a pick-up error. Was enough.

[0008]

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, the present invention provides an adhesive tape for fixing a semiconductor wafer, in which partial delamination during stretching is prevented, element pieces are easily peeled off from the adhesive tape, and pick-up errors are extremely reduced.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a styrene-ethylene-butene (pentene) copolymer has been used as a central layer of a base film. , 5 wt% or more and 20 wt%
% Of the polymer film containing a polymer of a carboxylic acid group-containing monomer component in an amount of not more than 10%, when stretched, there is no delamination, enabling a large and uniform expansion of the element gap and sticking of the element pieces. The inventors have found that it is easy to peel off from the tape and that there are very few pickup errors, and based on this finding, the present invention has been made.

That is, the present invention relates to 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 styrene-ethylene-butene or pentene-based material as a constituent layer. A film layer of a composition obtained by mixing a polymer obtained by polymerizing a monomer component containing a carboxylic acid group with the copolymer in an amount of 5% by weight or more and 20% by weight or less is provided. An adhesive tape for fixing a semiconductor wafer, which is a laminated film in which an adhesive coating layer is laminated on the radiation-curable adhesive layer side and a transfer prevention layer on the other side, via an adhesive layer or directly to the layer. To provide. Here, the term “radiation” refers to light such as ultraviolet light or ionizing radiation such as an electron beam.

The styrene-ethylene-butene or pentene copolymer in the present invention includes a styrene-ethylene-butene (or pentene) -styrene block copolymer. Modified products obtained by adding or substituting a low molecular compound such as maleic acid containing a functional group such as a carboxyl group, or modified products, conventionally known products such as a mixture of the copolymer and a general-purpose resin such as polyolefin, or a mixture thereof. And the like, 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, cost, and processability.

In the above block copolymer, the styrene polymer block preferably has an average molecular weight of about 2000 to 100,000, and its glass transition temperature is preferably 20 ° C. or higher. Also, ethylene-butene (pentene)
The polymer block preferably has an average molecular weight of about 10,000 to 400,000 and a glass transition temperature of -20 ° C or lower. Further, since the polymer blocks other than styrene in the block copolymer are ethylene-butene (pentene) copolymers, they are excellent in heat resistance.

In this styrene-ethylene-butene or pentene copolymer, the preferred weight ratio of the styrene component A to the ethylene-butene (pentene) component B is A
/ B = 5/95 to 50/50, more preferably A / B
= 10/90-30/70.

The polymer composed of a monomer component having a carboxylic acid group mixed with the styrene-ethylene-butene (pentene) copolymer of the present invention is a styrene-ethylene-butene (pentene) copolymer. There is no particular condition except that the resin is compatible with the coalescence, but a resin having radiation transparency and flexibility is preferably used. Here, the carboxylic acid group means a free or salt form of a carboxyl group, a carboxylic acid ester group and the like.

Examples of such a polymer include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic Acid methyl copolymer, ethylene-ethyl methacrylate copolymer, homopolymers such as ionomers, conventionally known copolymers and the like, or a mixture thereof, or a mixture with other resins and elastomers and the like. The type of the resin and the blend ratio of 5 wt% or more and 20 wt% or less can be arbitrarily selected according to various conditions such as required characteristics of the base film, cost, and processability.

The above-mentioned copolymer includes any copolymer such as a graft copolymer, and the above-mentioned mixture includes any mixed form such as an alloy and IPN.

Further, the blend ratio of the polymer containing a carboxylic acid group in the polymer component is 5 wt% to 20 wt%.
The following is assumed. If the amount is less than 5% by weight, the delamination cannot be improved, and the effect of improving the pick-up property cannot be obtained. If the amount exceeds 20% by weight, the rubber-like elasticity of the base film is impaired. This is because it becomes impossible to obtain a large and uniform gap amount of the element pieces required in the pickup device with image recognition.

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 film made of another resin is laminated on a blend film made of the styrene-ethylene-butene (pentene) -styrene copolymer of the present invention and a polymer containing a carboxylic acid group in the constituent components of the polymer. The obtained multilayer film can be used as the center layer of the base film.

The resin for the film to be laminated on the blend film is not particularly limited, but it is preferable that the resin has radiation transparency and flexibility, depending on various conditions such as the required characteristics of the base film, cost and processability. Type of resin,
The thickness ratio of the styrene-ethylene-butene (pentene) -based copolymer film or less, and the film on the radiation coin adhesive layer side can be arbitrarily selected.

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. . The pressure-sensitive adhesive applied layer is for preventing the contamination of the semiconductor wafer due to the peeling of the pressure-sensitive adhesive at the time of stretching the pressure-sensitive adhesive tape by increasing the adhesive force between the pressure-sensitive adhesive and the base film.

As the resin for the anti-transfer layer used in the present invention, for example, an ethylene-based resin is preferable, and low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer is preferable. 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% or less as the vinyl acetate copolymer.

As an adhesive for bonding the center layer and the pressure-sensitive adhesive coating layer or the transfer prevention layer, an ethylene-vinyl acetate copolymer, a maleic acid-modified ethylene-vinyl acetate copolymer, or a maleic acid-modified ethylene-α-olefin copolymer may be used. A conventionally known adhesive compound such as a polymer and a copolymerized polyester resin, or a mixture thereof can be used.

The ethylene-vinyl acetate copolymer used as an adhesive, which is modified with maleic acid, having a vinyl acetate content of 20% or more is preferred because 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 laminated film.
% Is more preferred. In addition, since the structure of the base film is more symmetrical when both are provided than when only one of the pressure-sensitive adhesive coating layer and the transfer prevention layer is provided, the end of the base film may curl to one side or the other. Therefore, there is an advantage that it is preferable in operation.

When the other side of the base film to which the radiation-curable pressure-sensitive adhesive is applied is textured or coated with a lubricant, blocking is prevented, and friction between the pressure-sensitive adhesive tape and the jig when the pressure-sensitive adhesive tape is stretched is reduced. This is preferable because necking of the base film is prevented.

A blend film composed of a styrene-ethylene-butene (pentene) copolymer and a polymer containing a carboxylic acid group in a component in an amount of 5% by weight or more and less than 20% by weight is simply used. When used in layers,
Although contamination of the semiconductor wafer due to peeling of the pressure-sensitive adhesive can be prevented, the advantages of the pressure-sensitive adhesive applied layer and the transfer prevention layer described above are unfavorably deteriorated.

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 an adhesive containing 10 to 200 parts by weight of a compound and 5 to 100 parts by weight of a linear polyester or polyol urethane acrylate compound having two carbon-carbon double bonds is used, an adhesive layer after irradiation Can maintain the rubber-like elasticity (flexibility) of the pressure-sensitive adhesive tape after radiation irradiation.

When the pressure-sensitive 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. In addition, if necessary, a radiation-curable silicon acrylate or silicon methacrylate, or a specially treated surface coated with a metal material on the surface of the semiconductor wafer to be adhered, in order to reduce the adhesive strength of the device after radiation irradiation properly. Similarly, in order to lower the adhesive strength for fixing the element, an ion sequestering agent or the like, a tackifier, an adhesion regulator, a surfactant, or the like, or other modifiers and common components can be blended. 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 is fully cut into a size of 3 × 3 mm with a dicing saw, cured with ultraviolet light, and then expanded with a wafer expansion device (air pressure: 2.0 kg / cm 2). The amount of device gap in the vertical and horizontal directions when the expand stroke was increased by 10 mm was measured to determine the size and uniformity of the device gap. Here, the element gap amount includes a blade thickness of 40 μm at the time of dicing.

3) Delamination The degree of delamination between the layers of the base film when the adhesive tape was stretched was examined. The peeling state between the layers of the pressure-sensitive adhesive tape when stretched by the wafer expansion device was evaluated in the same manner as when the element gap was measured. 4) Pick-up error rate The probability of pick-up error when picking up element pieces was examined.

Examples 1 to 7 and Comparative Examples 1 to 3 Using the extruder, a base film having each layer structure as shown in Tables 1 and 2 was prepared by using the following resin alone or kneaded blend composition. It was prepared by (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 substrate film was subjected to a corona treatment on the pressure-sensitive adhesive application side, and a pressure-sensitive adhesive was applied so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, to prepare a radiation-curable pressure-sensitive adhesive tape. .

The resins and adhesives used are as follows. Resin A (styrene - ethylene - butene copolymer): Shell Chemical Co. KRATON G-165 0 X resin B (maleic acid-modified styrene - ethylene - butene copolymer): manufactured by Asahi Kasei Tuftec M1943 resin C (styrene - ethylene - Penten copolymer): Septon 2043 EAA manufactured by Kuraray (ethylene-acrylic acid copolymer (acrylic acid content 9%)): PRIMAKOL 1 manufactured by Dow Chemical
410 EPR (ethylene-propylene-diene copolymer): manufactured by Nippon Synthetic Rubber EP 51 EEA (ethylene-ethyl acrylate copolymer) : Japan
Petrochemical Nisseki Lextron EEA A3100 EVA-10 (ethylene-vinyl acetate copolymer (vinyl acetate content 10%)): Evatate H manufactured by Sumitomo Chemical Co., Ltd.
2021F 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 Isocyanurate compound 80 parts by weight

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

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 maintains flexibility and has excellent stretchability even after irradiation with radiation, so that the gap between the elements by the adhesive tape can be reduced. Since large and uniform enlargement is possible, image recognition of element pieces becomes easy. In addition, since delamination hardly occurs when the adhesive tape is stretched, the element pieces are easily peeled off from the adhesive applied layer during pickup. Therefore,
There is an excellent effect that the element can be picked up easily and without damage.

──────────────────────────────────────────────────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 Inside Furukawa Electric Co., Ltd. (72) Inventor Morikuni Hasebe 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) C09J 7 / 02-7/04 H01L 21/301 H01L 21/52 WPI / L (QUESTEL)

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 is a styrene-ethylene-butene or pentene copolymer as a constituent layer. A film layer of a composition obtained by mixing a polymer obtained by polymerizing a monomer component containing a carboxylic acid group in an amount of 5% by weight or more and 20% by weight or less, An adhesive tape for fixing a semiconductor wafer, wherein the adhesive tape is a laminated film in which an adhesive application layer is laminated on the radiation-curable adhesive layer side and an anti-transfer layer is laminated on the other side via an adhesive layer or directly.