JP2011216704A - Adhesive tape for semiconductor wafer processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape for semiconductor wafer processing that reduces the occurrence of chipping caused during dicing.SOLUTION: The adhesive tape for semiconductor wafer processing having an adhesive layer formed on a base film is characterized in that the base film has a nonhydrogenated resin layer containing a nonhydrogenated styrene-isoprene-styrene block copolymer or nonhydrogenated styrene-butadiene-styrene block copolymer.

Description

  The present invention relates to an adhesive tape for processing semiconductor wafers, and more specifically, an adhesive for processing semiconductor wafers that can reduce chipping or cracking (hereinafter referred to as chipping) that occurs when a semiconductor wafer is cut and separated into small pieces. Regarding tape.

  In a manufacturing process of a semiconductor device such as an IC or LSI, the semiconductor wafer such as silicon or gallium arsenide is cut and separated (diced) into small pieces and then subjected to a pickup process. A general semiconductor wafer dicing step and pick-up step will be described with reference to the cross-sectional view shown in FIG.

  First, a semiconductor wafer 25 is attached to an adhesive tape 23 in which both ends are fixed to a holder 21 and an adhesive is applied on a base film (FIG. 3A), and the wafer is divided into small pieces (chips) by dicing. ) 27 (FIG. 3B). Next, in order to pick up the element piece 27, the expander 29 is pushed up in the direction in which the adhesive tape 23 is lifted (A direction in the figure), and the adhesive tape 23 is expanded in the direction toward the outside of the holder 21 (B direction in the figure). The space between the element small pieces 27 is expanded (FIG. 3C), and all of the element small pieces 27 or a part of the element small pieces 27 are picked up by the vacuum chuck 31 (FIG. 3D).

  Conventionally, in a process from a dicing process of a semiconductor wafer to a pickup process, an adhesive tape in which an adhesive is applied to a base film has been used. In such an adhesive tape, in consideration of expandability, a base material made of a relatively soft resin is used. For example, a polyvinyl chloride film or a polyethylene film may be used.

  During dicing, chipping or cracking called chipping occurs, and it is not uncommon for the size to be 100 μm or more. When chipping reaches the circuit surface, the performance of the circuit itself may be hindered. In addition, chip fragments generated by chipping during the pick-up process may adhere to the surface of another chip and destroy the circuit itself.

  Chipping is caused by contact between the tip and the blade due to vibration of the tip being cut by a rotary blade called a blade during dicing. Therefore, there is a method in which the wafer is completely fixed with wax instead of the adhesive tape so that vibration does not occur (see Patent Document 1). However, when dicing is repeatedly performed as in the manufacturing process, fixing and removing with wax becomes troublesome, which is not realistic. In addition, when the wax cannot be completely removed, it remains as contamination of the wafer, so that it is difficult to apply to an electronic device that is extremely disliked of the contaminant.

  Further, in order to provide a dicing film in which chips are not easily chipped during cutting in the dicing process of a semiconductor wafer, the styrene-butadiene copolymer hydrogen is used with respect to 100 parts by weight of the styrene-isoprene copolymer hydrogenated product. A substrate film for dicing having at least one layer containing an additive, a polypropylene resin, or a resin composition obtained by mixing 5 to 100 parts by weight of a mixture thereof is disclosed (see Patent Document 2). However, the chip chip prevention effect was not sufficient.

JP-A-7-169718 JP 2009-004568 A

  An object of the present invention is to provide a pressure-sensitive adhesive tape for processing a semiconductor wafer that can reduce the occurrence of chipping during dicing.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by applying a base film containing an unhydrogenated thermoplastic elastomer resin composition to an adhesive tape for processing semiconductor wafers. It was. The present invention has been made based on the above findings.

That is, the present invention provides the following inventions.
(1) In a pressure-sensitive adhesive tape for processing a semiconductor wafer having an adhesive layer on a base film, the base film is a non-hydrogenated styrene-isoprene-styrene block copolymer or a styrene-butadiene-styrene block. A pressure-sensitive adhesive tape for processing a semiconductor wafer, comprising an unhydrogenated resin layer containing an unhydrogenated copolymer.
(2) The base film is formed by laminating a plurality of layers, and one of the plurality of layers is the non-hydrogenated resin layer. Adhesive tape.
(3) The base film includes, in the plurality of layers, a first outer layer and a second outer layer, and the unhydrogenated resin layer is between the first outer layer and the second outer layer. (2) The adhesive tape for processing a semiconductor wafer according to (2).
(4) The pressure-sensitive adhesive tape for processing a semiconductor wafer according to (2) or (3), wherein the thickness of the unhydrogenated resin layer is 50% or more with respect to the total thickness of the base film. .
(5) In the unhydrogenated resin layer, the content of the unhydrogenated styrene-isoprene-styrene block copolymer or the unhydrogenated styrene-butadiene-styrene block copolymer The pressure-sensitive adhesive tape for processing a semiconductor wafer according to any one of (1) to (4), wherein the pressure-sensitive adhesive tape is 10 to 75 wt% with respect to the resin constituting the layer.
(6) Among the plurality of layers, at least one of the non-hydrogenated resin layers is a styrene-hydrogenated isoprene-styrene block copolymer, a styrene-hydrogenated butadiene-styrene block copolymer, or a styrene- The pressure-sensitive adhesive tape for processing a semiconductor wafer according to (2) or (3), comprising at least one copolymer selected from the group of hydrogenated isoprene / butadiene-styrene block copolymers.
(7) The adhesive tape for semiconductor wafer processing according to any one of (1) to (6), wherein the adhesive forming the adhesive layer is an acrylic adhesive.

  With the pressure-sensitive adhesive tape for processing a semiconductor wafer according to the present invention, it is possible to greatly reduce chipping in the processing of the wafer.

Sectional drawing which shows the adhesive tape 1 for semiconductor wafer processing which concerns on this invention. (A), (b) Sectional drawing which shows the adhesive tapes 13 and 17 for semiconductor wafer processing concerning this invention. (A)-(d) Sectional drawing explaining the dicing process and pick-up process of a semiconductor wafer. The figure which shows the loss coefficient of an unhydrogenated and hydrogenated styrene-type thermoplastic elastomer resin.

(Semiconductor wafer processing adhesive tape)
The adhesive tape 1 for processing a semiconductor wafer according to the present invention comprises a base film 3 and an adhesive layer 5 formed on the base film 3 as shown in the sectional view of FIG. Usually, the surface of the pressure-sensitive adhesive layer 5 is protected by applying an optional release liner 7 until it is used. In this invention, the adhesive tape 1 is also an adhesive sheet and contains what is called a dicing tape. In the pressure-sensitive adhesive tape 1 for processing a semiconductor wafer according to the present invention, the substrate film 3 contains a non-hydrogenated styrene-isoprene-styrene block copolymer or a non-hydrogenated styrene-butadiene-styrene block copolymer. A pressure-sensitive adhesive tape for processing semiconductor wafers, comprising an additive resin layer. In each figure, the same reference sign means the same thing, and explanation of some drawings is omitted. Moreover, the size of each component is schematic and does not indicate the actual scale.

  Further, when a stretchable film is interposed in the base film 3, for example, when the stretchable film is laminated on the side where the adhesive layer of the base film 3 is not provided, the expansion can be easily performed. Specific examples of such resins include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ethylene / propylene copolymer, propylene copolymer, and ethylene-propylene-diene copolymer vulcanization. , Polybutene, polybutadiene, polymethylpentene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid methyl copolymer, ethylene- (meth) acrylic acid ethyl copolymer Polymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, polyurethane, polyamide, ionomer, nitrile rubber, butyl rubber, styrene isoprene rubber, styrene butadiene rubber, natural rubber and the like Films made of water additives or modified products It is used. These stretchable films can be used by combining or laminating two or more of these resins.

  Chipping is caused by a rotary blade called a blade at the time of dicing, and the inventors of the present invention diligently studied the cause of the chipping, and the chip during cutting vibrates due to the rotation of the blade. And the blade was found to come into contact.

  Therefore, the pressure-sensitive adhesive tape for processing a semiconductor wafer according to the present invention prevents chipping by providing a vibration damping characteristic in order to attenuate chip vibration generated during dicing. The vibration damping characteristic is a characteristic that reduces vibration by converting vibration energy into heat energy. There is a loss factor (Tanδ) as an index for evaluating the vibration damping characteristics, and this loss factor is calculated by measuring dynamic viscoelasticity.

Here, a general method for measuring dynamic viscoelasticity will be described. This method is a method in which a periodic micro-strain is given to a test specimen and the response to the micro-strain is measured. It is possible to know how much both elastic and viscous elements are included. If the test body is a perfect elastic body, the response to it appears in the same phase, and the loss coefficient determined by the ratio of the storage elastic modulus and the loss elastic modulus becomes zero. However, if there is a viscous element, a delay occurs in the response, and the loss coefficient takes a positive value.
The storage elastic modulus appears due to the elastic element, and when the elastic element is deformed by applying stress, it receives a response to it and has the property of conserving mechanical energy, whereas the loss elastic modulus is attributed to the viscous element When it is deformed by stress application, mechanical energy corresponding to the applied stress has a property of being consumed as heat.
In the present invention, the stress is given from the rotation of the blade during dicing, but if the loss coefficient of the adhesive tape for semiconductor wafer processing is greater than a specific value, the vibration of the chip corresponding to the recovery of deformation against the stress is suppressed. Therefore, chipping can be reduced.

  When dicing with the blade, heat is generated by contact between the rotating blade and the wafer. The rotation speed of the blade is normally 25000-55000 rpm, and when the value is converted into a frequency, it becomes 400-900 Hz. In order to suppress normal heat generation, cooling water of 15 to 25 ° C. is flowed to the contact portion during dicing, and the conductive wafer processing adhesive tape is kept at a substantially constant temperature (for example, 23 ° C.). By setting the minimum loss coefficient of the adhesive tape for semiconductor wafer processing at a temperature of 23 ° C. and a frequency of 400 to 900 Hz to 0.20 or more, chip vibration generated during dicing can be attenuated and chipping can be prevented.

(Unhydrogenated resin layer)
In FIG. 2 which is a cross-sectional view showing pressure-sensitive adhesive tapes 13 and 17 for processing a semiconductor wafer according to the present invention, the unhydrogenated resin layer 11 includes an unhydrogenated styrene-isoprene-styrene block copolymer, styrene-butadiene- It is composed of a non-hydrogenated styrene block copolymer alone or a blend of styrene-isoprene-styrene block copolymer unhydrogenated or styrene-butadiene-styrene block copolymer unhydrogenated with another resin. Is desirable.

  Other resins blended with these unhydrogenated products include polypropylene, low density polyethylene, medium density polyethylene, linear low density polyethylene which is an ethylene-α olefin copolymer, or ultra low density polyethylene, α- Resins whose olefins are propylene, butene-1, octene-1, 4methylpentene-1, hexene-1 and octene-1, styrene copolymers, ethylene-vinyl acetate copolymers (hereinafter referred to as "EVA") , Ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (hereinafter referred to as “EMMA”), ethylene-methacrylic acid copolymer (hereinafter referred to as “EMMA”). , "EMAA"), ethylene-ethyl methacrylate copolymer Body or a mixture of these resins.

  In the present invention, the unhydrogenated styrene-isoprene-styrene block copolymer or the unhydrogenated styrene-butadiene-styrene block copolymer contained in the unhydrogenated resin layer 11 of the base film 3 is Since the structure has rubber elasticity due to the inclusion of many double bonds in the structure, it has a high loss factor and is highly effective in reducing chipping.

  The unhydrogenated styrene block copolymer (styrene thermoplastic elastomer resin) used in the unhydrogenated resin layer 11 of the present invention is a polymer block composed of styrene units and a polymer composed of isoprene units or butadiene units. A block copolymer composed of blocks in which a carbon-carbon double bond based on an isoprene unit or a butadiene unit is not hydrogenated is used. Hydrogenation is a hydrogenation reaction (hydrogenation) in which an unsaturated bond is reduced with hydrogen.

  The content of styrene units in the unhydrogenated styrene-isoprene-styrene block copolymer or unhydrogenated styrene-butadiene-styrene block copolymer is preferably 5 to 40% by weight, and more Preferably it is 5 to 25% by weight. If the content is less than 5% by weight, the styrene-isoprene-styrene block copolymer or the styrene-butadiene-styrene block copolymer may not be stably polymerized. This is because it may become brittle. Note that, by reducing the rigidity of the copolymer, the extrusion processability is improved, and the thickness unevenness can be further reduced.

  Further, the number of parts of the styrene block copolymer unhydrogenated product (styrene-based thermoplastic elastomer unhydrogenated product) in the present invention is 10 to 75 wt% in the resin constituting the unhydrogenated resin layer 11. It is preferable. If the content of the unhydrogenated styrenic block copolymer in the present invention is too small, sufficient vibration damping properties may not be obtained, and the chipping suppression effect may be small. Moreover, when there is too much content of a styrene-type block copolymer unhydrogenated film, the film itself will become too soft and handling and cutting property will deteriorate.

  In the conventional use example of the styrene thermoplastic elastomer resin, a styrene thermoplastic elastomer resin to which hydrogen is added is used. The reason for adding hydrogen is due to oxidative degradation of styrene-isoprene-styrene block copolymer or styrene-butadiene-styrene block copolymer due to oxygen in the atmosphere caused by the presence of double bonds in isoprene or butadiene. This is for preventing the resin from becoming brittle and improving the weather resistance.

  Although the weather resistance of the styrene-based thermoplastic elastomer resin composition is improved by hydrogenation, the rubber elasticity is reduced by reducing double bonds in the structure, and unhydrogenated styrene-based thermoplastics. Compared to the elastomer resin composition, the peak temperature of the loss coefficient is lowered. Therefore, the styrene-based thermoplastic elastomer hydrogenated product is less effective in improving the chipping performance under the environment in the region near 23 ° C. using the semiconductor wafer processing adhesive tape.

  Moreover, the adhesive tape 1 comprises the base film 3 using the unhydrogenated resin layer 11 and the outer layer 15 like the adhesive tape 13 shown in FIG. The pressure-sensitive adhesive layer 5 may be provided, or the base film 3 with the unhydrogenated resin layer 11 sandwiched between the first outer layer 15a and the second outer layer 15b as in the pressure-sensitive adhesive tape 17 shown in FIG. May be configured.

  In particular, as shown in FIG. 2B, in the adhesive tape 17 for processing a semiconductor wafer, the base film 3 is composed of at least the unhydrogenated resin layer 11 and the first outer layer 15a and the second outer layer 15b on both sides thereof. By constituting the resin layer of at least one layer, the resin layer of the outer layer 15 protects the portion of the unhydrogenated resin layer 11 where the unhydrogenated styrenic thermoplastic elastomer resin is exposed to oxygen in the atmosphere. It is possible to provide a pressure-sensitive adhesive tape for processing semiconductor wafers which prevents brittleness due to oxidative deterioration caused by the presence of bonds, has excellent weather resistance, and has excellent chipping performance.

(Outer layer)
The constituent resin of the outer layer 15 is, for example, a resin compatible with an unhydrogenated styrene-isoprene-styrene block copolymer or an unhydrogenated styrene-butadiene-styrene block copolymer, and a thermoplastic resin having rubber elasticity. Preferably it consists of. As such a thermoplastic resin, for example, polypropylene, low density polyethylene, medium density polyethylene, linear low density polyethylene which is an ethylene-α olefin copolymer or ultra low density polyethylene, and α-olefin is propylene, Butene-1, octene-1, 4methylpentene-1, hexene-1, octene-1 resin, styrene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-methyl acrylate copolymer, Of ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, ethylene-methyl methacrylate copolymer (EMMA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl methacrylate copolymer, or these resins It may be a mixture. Particularly preferably, as the styrene-based copolymer, a styrene-hydrogenated isoprene-styrene block copolymer, a styrene-hydrogenated butadiene-styrene block copolymer, a styrene-hydrogenated isoprene / butadiene-styrene block copolymer, or these And a copolymer of these copolymers and the above-mentioned thermoplastic resin. When these copolymers are mixed with the above-described thermoplastic resin, the content of these copolymers is preferably 10 to 75 wt% with respect to the resin constituting the outer layer 15. By applying these copolymers, the unhydrogenated resin layer is excellent in compatibility with the unhydrogenated thermoplastic elastomer resin layer, and the unhydrogenated resin layer is prevented from being deteriorated by oxygen in the atmosphere. An adhesive tape for processing a semiconductor wafer excellent in chipping performance can be provided.

  The thickness of the unhydrogenated resin layer 11 is 50% or more, preferably 70% or more with respect to the thickness of the entire base film 3. By setting it as such layer thickness, since a blade edge | tip becomes easy to bite in in a tape, it comes to be able to cut very easily. By making it easy to cut, in addition to reducing cut mistakes and improving yield, the line speed can be increased and productivity can be greatly improved. When the thickness of the unhydrogenated resin layer 11 is less than 50% with respect to the entire thickness of the base film 3, the cutting edge is difficult to bite into the tape, so that a cut mistake occurs. In the semiconductor production line, most of the transition to each process such as tape bonding, tape cutting, dicing, etc. is performed fully automatically. If a cut error occurs, the process is stopped and the production yield is increased. Gets worse. In addition, the thickness of the unhydrogenated resin layer 11 is preferably 30 to 100 μm, more preferably 45 to 90 μm, and still more preferably 50 to 80 μm.

  Further, among the layers constituting the base film, the surface in contact with the pressure-sensitive adhesive layer 5 may be subjected to corona treatment or other layers such as a primer in order to improve adhesion. The thickness of the base film 3 is not particularly limited, but is preferably 30 to 200 μm, particularly preferably 50 to 100 μm.

(Adhesive layer)
The pressure-sensitive adhesive layer 5 can be formed of various conventionally known pressure-sensitive adhesives. Such an adhesive is not limited at all, but for example, an adhesive having a base polymer such as rubber, acrylic, silicone or polyvinyl ether is used. The thickness of the pressure-sensitive adhesive layer 5 is preferably 5 to 20 μm, more preferably 8 to 12 μm.

  In order to add cohesion to these base polymers, a crosslinking agent can be blended. Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a metal chelate-based crosslinking agent, an aziridine-based crosslinking agent, and an amine resin corresponding to the base polymer. Further, the pressure-sensitive adhesive can contain various additive components as desired within the range in which the object of the present invention is not impaired.

  A radiation-curing type or heat-foaming type pressure-sensitive adhesive can also be used. As the radiation curable adhesive, an adhesive that is cured by ultraviolet rays, electron beams, etc., and can be easily peeled off at the time of peeling can be used. An adhesive that easily peels can be used. Further, the adhesive may be an adhesive that can be used for dicing and die bonding. As the radiation curable pressure-sensitive adhesive, for example, those described in JP-B-1-56112 and JP-A-7-135189 are preferably used, but are not limited thereto. In the present invention, it is preferable to use an ultraviolet curable adhesive. In that case, it is only necessary to have a property of being cured by radiation to form a three-dimensional network. For example, at least two photopolymerizations in a molecule relative to a normal rubber-based or acrylic pressure-sensitive base resin (polymer). A compound comprising a low molecular weight compound having a reactive carbon-carbon double bond (hereinafter referred to as a photopolymerizable compound) and a photopolymerization initiator is used.

  The above rubber-based or acrylic base resins are natural rubber, rubber polymers such as various synthetic rubbers, or poly (meth) acrylic acid alkyl esters, (meth) acrylic acid alkyl esters, (meth) acrylic acid alkyl esters. And an acrylic polymer such as a copolymer of the above and other unsaturated monomer copolymerizable therewith.

Moreover, an initial stage adhesive force can be set to arbitrary values by mixing an isocyanate type hardening | curing agent in said adhesive. Specific examples of such a curing agent include polyvalent isocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane. -4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, Lysine isocyanate and the like are used.
In the case of an ultraviolet curable pressure-sensitive adhesive, by mixing a photopolymerization initiator in the pressure-sensitive adhesive, it is possible to reduce the polymerization curing time and the amount of ultraviolet irradiation by ultraviolet irradiation.

  Specific examples of such a photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethyl thiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone and the like can be mentioned.

(Release liner)
The tape for processing a semiconductor wafer of the present invention is usually supplied as a release liner 7 laminated on an adhesive layer, and the release liner 7 is peeled off before use. As the release liner 7, paper impregnated with silicone oil or wax, or a release plastic film is preferably used. Moreover, the thickness of this release liner 7 should just be thickness which does not have trouble in roll winding, for example, is about 5-300 micrometers, Preferably it is 20-50 micrometers.

  According to the present invention, an unhydrogenated thermoplastic elastomer resin having an excellent loss factor in the vicinity of a region of 23 ° C. is applied to a base film of an adhesive tape for processing a semiconductor wafer, thereby providing a semiconductor wafer having excellent chipping performance. An adhesive tape for processing can be provided.

  Further, according to the present invention, an unhydrogenated resin layer containing an unhydrogenated resin is sandwiched between a first outer layer and a second outer layer that do not contain an unhydrogenated resin, whereby unhydrogenated by oxygen in the atmosphere. It is possible to provide a pressure-sensitive adhesive tape for processing a semiconductor wafer that suppresses a double bond reaction of a styrene-based thermoplastic elastomer resin and has excellent weather resistance.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples. In the following examples, each characteristic was tested and evaluated as follows.

(Measurement of loss factor of unhydrogenated resin / hydrogenated resin)
Using the following unhydrogenated resin and hydrogenated resin, the loss factor of the resin constituting the substrate was measured.
Unhydrogenated resin: styrene-isoprene-styrene block copolymer unhydrogenated product; Kuraray Co., Ltd. Highbler 5125
Hydrogenated resin: styrene-hydrogenated isoprene-styrene block copolymer; Hibler 7125 manufactured by Kuraray Co., Ltd.

These resins are molded into a sheet shape by hot pressing, and then a rheovibron dynamic viscoelasticity measuring device DDV-III (manufactured by AND) is used, and the temperature rising rate is 3 ° C./min, and the frequency is −100 ° C. to 50 ° C. The loss coefficient at the time of temperature dispersion at ° C was measured.
The result of the loss factor measurement in the sheet form of the resin is shown in FIG.

  As shown in FIG. 4, the loss factor of the unhydrogenated styrene thermoplastic elastomer resin is higher than that of the hydrogenated styrene thermoplastic elastomer resin at a temperature around 15 to 30 ° C. In particular, unhydrogenated styrene-based thermoplastic elastomer resin exhibits an excellent loss factor as compared with hydrogenated styrene-based thermoplastic elastomer resin in an environment in the vicinity of 23 ° C. using an adhesive tape for processing semiconductor wafers. For this reason, if an unhydrogenated styrene-based thermoplastic elastomer resin can be used in producing an adhesive tape for processing semiconductor wafers, it can have excellent chipping performance.

(Production and evaluation of adhesive tape for semiconductor wafer processing)
Each evaluation of a chipping property, a loss factor, an expandability, cutting property, and a weather resistance was performed using the adhesive tape for semiconductor wafer processing of the Example and comparative example created in the following way.

  In this example / comparative example, as shown in FIG. 2B, the intermediate layer (non-hydrogenated resin layer in the example) is sandwiched between the first outer layer and the second outer layer, and the second layer An adhesive layer is formed on the outer layer.

  The adhesive tape for processing a semiconductor wafer was prepared by extruding a base material film having each layer structure as shown in Table 1 with a resin alone or a kneader kneaded blend composition (co) using an extruder. The thickness of the obtained base film is all 100 μm. The obtained base film was subjected to corona treatment on the pressure-sensitive adhesive application side, and the pressure-sensitive adhesive was applied so that the thickness of the pressure-sensitive adhesive layer after drying was 10 μm, thereby preparing a pressure-sensitive adhesive tape for semiconductor wafer processing. Each evaluation of this adhesive tape was tested according to the evaluation method. The results are shown in Table 1. In addition, the number in the parenthesis in Table 1 means wt% of the blending ratio of the resin, and PP (50) + SIS (50) means that PP and SIS are mixed at a ratio of 50 wt%.

The base material constituting resin and the pressure-sensitive adhesive used in this example and comparative example are as follows.
(Substrate constituent resin)
SIS: unhydrogenated styrene-isoprene-styrene block copolymer;
Kuraray Co., Ltd. Highblur 5125
SEPS: styrene-hydrogenated isoprene-styrene block copolymer;
Made by Kuraray Co., Ltd.
SBS: styrene-butadiene-styrene block copolymer unhydrogenated product;
Clayton D made by Kraton Polymer Japan Co., Ltd.
SEBS: styrene-hydrogenated butadiene-styrene block copolymer;
Clayton G made by Kraton Polymer Japan Co., Ltd.
PP: Homo polypropylene; J-105G manufactured by Ube Industries
PE: Low-density polyethylene; Tosoh Petrocene 205
EVA: ethylene-vinyl acetate copolymer; manufactured by Ube Industries, Ltd. V212
EMAA: Ethylene-ethyl methacrylate copolymer; Nukurel N1214 manufactured by Mitsui DuPont Polychemical Co., Ltd.

(Adhesive)
Polyisocyanate compound (manufactured by Nippon Polyurethane Co., Ltd.) in 100 parts by mass of acrylic base polymer (copolymer comprising 2-ethylhexyl acrylate, methyl acrylate, 2-hydroxyethyl acrylate, weight average molecular weight 200,000, glass transition point = −35 ° C.) , Trade name Coronate L) 3 parts by mass, 10 parts by mass of tetramethylolmethane tetraacrylate as a compound having a photopolymerizable carbon-carbon double bond, 1 part by mass of α-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator, Obtained by mixing.

(Weather resistance test)
A test piece having a width of 25 mm and a length of 100 mm was cut out from the adhesive tape for semiconductor processing of the examples and comparative examples, left in a dark environment at a constant environment of 23 ° C. and a humidity of 50%, and visually observed after a certain period of time. Evaluation was made according to the following criteria.
◎: No yellowing after 3 months ○: Yellowing within 1-3 months ×: Yellowing within 1 month

(Cutting test)
When cutting the tape into a circle, a rotary cutter with a rounded edge was used to measure whether the tape could be cut smoothly.
◎: Completely cut over the entire circumference ○: 2/3 or more could be cut Δ: 1/3 or more was an uncut portion ×: Could not be cut

(Expandability test)
A 6-inch wafer was mounted on the semiconductor processing pressure-sensitive adhesive tapes of Examples and Comparative Examples, and dicing was performed (chip size is 5 mm square). After UV irradiation (500 mJ / m ² ), the width of the chip was measured by pulling down the fixing ring by 10 mm with a die bonder (manufactured by NEC Machinery, CPS-100FM, trade name).
: 300um ~
○: 100 to 300 um
Δ: 50 to 100 um
×: 50 um or less

(Measurement of loss factor of tape)
A test piece having a width of 5 mm and a length of 10 mm was cut out from the adhesive tape for processing a semiconductor wafer in Examples and Comparative Examples. The test piece is fixed to a supporting jig of a dynamic viscoelasticity measuring apparatus (Rheogel-E4000, manufactured by UBM), measured at a temperature of 23 ° C. and a frequency of 400 to 900 Hz, and the loss coefficient within the range is minimized. Got the value.

(Chipability evaluation)
A surface gold vapor-deposited wafer having a diameter of 6 inches and a thickness of 350 μm is bonded to the adhesive tape for processing semiconductor wafers in Examples and Comparative Examples, and a chip size is 5 mm using a dicing apparatus (manufactured by DISCO, DAD-340). Dicing was performed so as to form corners. The dicing conditions are: a rotating round blade rotation speed: 40000 rpm, a cutting speed: 100 mm / s, and a cutting water flow rate of 20 mL. Moreover, the depth which a rotary round blade cuts into an adhesive tape in the case of dicing was performed so that it might be set to 30 micrometers.
After dicing, UV irradiation is performed (500 mJ / m ² ), 50 chips are randomly taken out from one wafer, and the maximum chipping value on each side of the chip back surface (adhesive surface) is measured with a microscope (100 to 200 times). The average of all values was calculated.

(Comprehensive evaluation)
A comprehensive evaluation was made in consideration of weather resistance, cutting properties, expandability, loss factor and chipping properties.
◎: Good ○: Pass △: Level that can be used as a product ×: Fail

  As is clear from any of the examples, the inclusion of SIS or SBS, which is an unhydrogenated styrenic thermoplastic elastomer resin having an excellent loss factor, in the intermediate layer of the base film is superior to the comparative example. An adhesive tape for processing semiconductor wafers that exhibits chipping performance and is effective as a dicing tape with weatherability, cutting performance, expandability, and chipping performance could be obtained.

Further, when Comparative Example 4, Example 4, and Example 3 are compared, it can be seen that the thickness of the unhydrogenated resin layer is preferably 50% or more with respect to the total thickness of the base film.
Further, when Comparative Example 5, Example 5, Example 2, Example 3, Example 6, and Comparative Example 6 are compared, the content of SIS or SBS is relative to the resin constituting the unhydrogenated resin layer. It turns out that it is preferable that it is 10-75 wt%.

DESCRIPTION OF SYMBOLS 1 ......... Adhesive tape for semiconductor wafer processing 3 ......... Base film 5 ......... Adhesive layer 7 ......... Release liner 11 ......... Unhydrogenated resin layer 13 ......... Adhesive tape for semiconductor wafer processing 15 ……… Outer layer 17 ……… Semiconductor wafer processing adhesive tape 21 ……… Holder 23 ……… Adhesive tape 25 ……… Semiconductor wafer 27 ……… Element chip (semiconductor chip)
29 ……… Expander 31 ……… Vacuum chuck

Claims (7)

  In a pressure-sensitive adhesive tape for processing a semiconductor wafer having a pressure-sensitive adhesive layer on a base film, the base film is a non-hydrogenated styrene-isoprene-styrene block copolymer or a styrene-butadiene-styrene block copolymer. A pressure-sensitive adhesive tape for processing a semiconductor wafer, comprising an unhydrogenated resin layer containing an unhydrogenated product. The base film is formed by laminating a plurality of layers,
The pressure-sensitive adhesive tape for processing a semiconductor wafer according to claim 1, wherein one of the plurality of layers is the non-hydrogenated resin layer. The base film includes a first outer layer and a second outer layer in the plurality of layers,
The pressure-sensitive adhesive tape for processing a semiconductor wafer according to claim 2, wherein the non-hydrogenated resin layer is located between the first outer layer and the second outer layer.   The pressure-sensitive adhesive tape for semiconductor wafer processing according to claim 2 or 3, wherein the thickness of the unhydrogenated resin layer is 50% or more with respect to the total thickness of the base film.   In the unhydrogenated resin layer, the content of the unhydrogenated styrene-isoprene-styrene block copolymer or the unhydrogenated styrene-butadiene-styrene block copolymer constitutes the unhydrogenated resin layer. The pressure-sensitive adhesive tape for processing a semiconductor wafer according to claim 1, wherein the pressure-sensitive adhesive tape is 10 to 75 wt% with respect to the resin to be processed.   Among the plurality of layers, at least one of the non-hydrogenated resin layers is a styrene-hydrogenated isoprene-styrene block copolymer, a styrene-hydrogenated butadiene-styrene block copolymer, or a styrene-hydrogenated isoprene. 4. The pressure-sensitive adhesive tape for processing a semiconductor wafer according to claim 2 or 3, comprising at least one copolymer selected from the group of / butadiene-styrene block copolymers.   The pressure-sensitive adhesive tape for forming a semiconductor wafer according to any one of claims 1 to 6, wherein the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive.

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