TWI494226B - Adhesive tape for semiconductor wafer protection - Google Patents

Description

Adhesive tape for semiconductor wafer protection Technical field

The present invention relates to an adhesive tape for semiconductor wafer protection used in a gas etching process and a plasma cutting process.

Background technique

After the semiconductor wafer is formed on the surface of the wafer, the back side of the wafer is subjected to a grinding process, and a back grinding process for adjusting the thickness of the wafer and a cutting process for slicing the wafer according to a predetermined wafer size are performed.

In recent years, IC cards have become widespread and the capacity of USB memory has rapidly increased, and the number of wafers to be overlapped has increased, and there has been a demand for further thinning. Therefore, semiconductor wafers having a thickness of about 200 μm to 350 μm have to be thinned to a thickness of 50 to 100 μm or less.

Further, although the necessity of increasing the number of laminated wafers for the purpose of improving the function, the thin film formation of the wafer has been developed, but the amount of wafer used has also increased, so that it is necessary to increase the number of wafers that can be manufactured in a single process. Corresponding to this, the wafer has been enlarged in diameter, and currently processing with 12 吋 (300 mm) wafers is the mainstream. However, in order to further improve the processing efficiency of the wafer, a review of 18 吋 (450 mm) wafer processing has also been conducted.

3(a) and 3(b) are layout diagrams showing wafers on a small-diameter semiconductor wafer 21 and a large-diameter semiconductor wafer 31. As shown in Fig. 3(a), in the wafer arrangement in which the wafers 23 are arranged in a checkerboard pattern, the cutting can be performed by a conventional cutting blade. However, when a wafer having a larger size such as a memory device is formed at a wafer diameter of 300 mm or more, the pattern is formed on the surface of the wafer, and the field of unusable use is increased, resulting in a wafer that cannot be used as a product. increase. Therefore, in order to increase the yield of the wafer, as shown in FIG. 3(b), the wafer 33 is densely arranged toward the outer periphery of the semiconductor wafer 31. Since the wafers are arranged at equal intervals so far (Fig. 3(a)), the wafers are arranged in various directions instead of the equal directions (Fig. 3(b)), so the cutting lanes (cutting lines) are not straight lines, and it is difficult Straight cut with a blade.

In order to solve the above problems, it has been proposed to use a laser or the like to cut a condition other than a straight line, irradiate laser light into the inside of the semiconductor wafer, selectively form a modified portion, and form a cutting line with the modified portion as a starting point. A so-called stealth dicing method for dividing a semiconductor wafer (Patent Document 1). However, by laser cutting the wafer, the wafer will be damaged, so that the bending strength of the remaining wafer is not improved.

For the above problem, a method of plasma cutting has been proposed (Patent Document 2). Plasma cutting is a method of selectively etching a portion of a semiconductor wafer that is not covered by a mask by plasma. By the above cutting method, the wafer can be selectively sliced, and the cutting can be performed normally even if the cutting track is bent. Moreover, the etching rate is extremely high, so in recent years, it has become one of the processes most suitable for wafer segmentation. However, when plasma cutting, a fluorine-based gas that is highly reactive with a wafer such as sulfur hexafluoride (SF6) or carbon tetrafluoride (CF4) is used. As a gas for plasma generation, it is necessary to protect the surface which is not etched by a mask due to its high etching rate, and it is shielded by a resist or tape beforehand. Further, after the plasma is etched, a state in which the film remains is formed. Therefore, various problems such as the use of a large amount of solvent to remove the resist or the residue cannot be removed, resulting in defects such as a germanium wafer, have not yet been solved, so that it has not yet been popularized. .

Further, the plasma cutting method exposes the wafer to the plasma to generate a high temperature state by heat generation, and causes a problem of heating deterioration of the adhesive tape for semiconductor wafer protection. The adhesive tape for semiconductor wafer protection after heat deterioration deteriorates the adhesive on the adhesive body, loses the peeling function, and loses the effect of the adhesive tape for semiconductor wafer protection.

In addition, in recent years, a new method of processing by a gas cluster etching method which suppresses the energy applied to a wafer and controls the etching rate after processing by the above-described stealth cutting method has been newly proposed. The gas cluster etching method is a method in which a gas is blown into a vacuum environment to form a cluster of gas molecules, and the wafer is processed to collide with the wafer (Patent Document 3). After the cluster of collision wafers applies kinetic energy to the wafer, it will decompose into gas molecules and scatter. Thereby, etching of the wafer surface can be performed. By applying the above etching treatment after the processing of the stealth cutting method, the modified portion formed by the laser can be removed, and the bending strength is expected to be improved. Further, in the gas cluster etching method, chlorine trifluoride (ClF ₃ ) is used as the reaction gas, and the combination of Cl-F is extremely small, so that it is not required to be pre-ionized beforehand, such as a plasma generating gas such as carbon tetrafluoride (CF ₄ ). Therefore, the damage to the substrate is extremely small, and it is not necessary to protect by the mask, and the wafer can be easily cut and processed.

Gas etching process and electricity using gas cluster etching The slurry cutting process is the same, and when wafer processing is performed, the phenomenon of heat generation is caused by the chemical reaction between the wafer and the gas molecules. The above-mentioned heat generation may also exceed 200 ° C. The processing method with the above-mentioned heat generation must prevent the base film from being thermally fused to the chuck holding the semiconductor wafer protective tape, or the substrate film shrinks and the semiconductor wafer is damaged. .

Advanced technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2003-33887

Patent Document 2: Japanese Patent Laid-Open Publication No. 2007-19386

Patent Document 3: Japanese Patent Laid-Open Publication No. 2011-171584

Summary of invention

SUMMARY OF THE INVENTION The object of the present invention is to provide an adhesive tape for semiconductor wafer protection having heat resistance and heat shrink resistance which is not adhered to a chuck or excessively shrinkage even when exposed to a high temperature in a gas etching process and a plasma cutting process. .

In order to achieve the above object, the following invention is provided.

(1) An adhesive tape for protecting a semiconductor wafer, comprising: an adhesive layer formed on one surface of a base film and a base film, wherein the base film is the most side on which the adhesive layer is not formed The outer layer has a cast film layer containing a hardened resin, so that the probe made of SUS304 having a diameter of 3.0 mm is brought into contact with the measurement sample at a speed of 30 mm/min, and the contact load is 100 gf. When the contact time was 1 second, the peak of the adhesion of the cast film layer measured by the probe test when the probe was peeled upward at a peeling speed of 600 mm/min was 100 kPa or less at 200 °C.

(2) The adhesive tape for protecting a semiconductor wafer according to (1), wherein the base film is composed only of a cast film layer.

(3) The adhesive tape for protecting a semiconductor wafer according to (1) or (2), wherein the cast film layer contains a cured acrylic copolymer or a polyester resin.

(4) The adhesive tape for protecting a semiconductor wafer according to any one of (1) to (3), wherein the cast film layer is composed of an acrylic copolymer which has been cured by a curing agent or radiation.

(5) The adhesive tape for protecting a semiconductor wafer according to any one of (1) to (4), wherein the breaking strength is 0.5 N/mm or more, and the elongation at break is 200% or more.

(6) The adhesive tape for protecting a semiconductor wafer according to any one of (1) to (5), wherein the speed of the probe made of SUS304 having a diameter of 3.0 mm is 30 mm/min when it is brought into contact with the measurement sample. When the contact load is 100 gf and the contact time is 1 second, the adhesion of the adhesive layer measured by the probe test when the probe is peeled upward at a peeling speed of 600 mm/min is 25 ° C. The next is 50~400kPa.

According to the present invention, it is possible to provide a semiconductor wafer protective adhesive having heat resistance and heat shrink resistance which is not adhered to a chuck or excessively shrinkage even when exposed to a high temperature in a gas etching process or a plasma cutting process. band.

1, 1a‧‧‧Semiconductor wafer protection Adhesive tape

3‧‧‧Substrate film

5‧‧‧Adhesive layer

7‧‧‧ cast film layer

9‧‧‧ resin film layer

11‧‧‧ wafer

13‧‧‧etching gas

15‧‧‧Ring frame

17‧‧‧ chuck

21‧‧‧Semiconductor wafer

23‧‧‧ wafer

31‧‧‧Semiconductor wafer

33‧‧‧ wafer

Fig. 1(a) is a cross-sectional view showing the adhesive tape 1 for semiconductor wafer protection of the embodiment, and Fig. 1(b) is a cross-sectional view showing the adhesive tape 1a for semiconductor wafer protection of the embodiment.

Fig. 2 illustrates a gas etching process using the adhesive tape 1 for semiconductor wafer protection of the present embodiment.

Figure 3 (a) is a configuration diagram of a wafer on a small-diameter semiconductor wafer. (b) is a configuration diagram of a wafer on a large-diameter semiconductor wafer.

Form for implementing the invention

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 1(a) is a cross-sectional view showing the adhesive tape 1 for semiconductor wafer protection of the embodiment, and Fig. 1(b) is a cross-sectional view showing the adhesive tape 1a for semiconductor wafer protection of the embodiment.

The adhesive tape 1 for semiconductor wafer protection includes a base film 3 and an adhesive layer 5 provided on the base film 3. Further, each layer may be pre-divided (precut) into a predetermined shape in accordance with a program and a device. Further, the adhesive tape 1 for semiconductor wafer protection of the present embodiment may be in a form in which the wafer is divided into a single wafer or a long sheet is wound into a tubular shape. Hereinafter, the structure of each layer will be described.

<Substrate film>

The base film 3 is provided with a cast film layer 7 containing a hardened resin on the outermost layer on the side where the adhesive layer 5 is not formed. Moreover, in Fig. 1(a), although the laminate is shown In the base film 3 of the cast film layer 7 and the resin film layer 9, the resin film other than the resin film layer 9 may be laminated on the base film 3 only if the outermost layer is the cast film layer 7.

The cast film layer is a layer formed by coating a resin composition. The cast film layer 7 uses a resin which can be crosslinked and has a three-dimensional mesh structure, so that it is not easily softened when exposed to a high temperature, and is not easily fused to the chuck. Further, since the cast film layer 7 is formed by brushing, the residual stress is small, heat shrinkage is less likely to occur at a high temperature, and wafer position shift in the gas etching process is less likely to occur.

Further, as shown in FIG. 1(b), the base film 3 may be formed of only the cast film layer 7, and the adhesive layer 5 may be provided on the one side of the cast film layer 7 to protect the semiconductor wafer. Tape 1a. When the base film 3 is composed only of the cast film layer 7, the entire base film 3 is composed of a cast film layer, so that the adhesive tape 1a for semiconductor wafer protection and the resin film layer 9 and the cast film layer 7 are laminated. The adhesive tape 1 for semiconductor wafer protection of the base film 3 can constitute an adhesive tape having a low heat shrinkage ratio. Since the heat shrinkage rate of the adhesive tape 1a for semiconductor wafer protection is low, in the gas etching process exposed to a high temperature, the position of the wafer of the adherend is less likely to occur, and bending and shrinkage are less likely to occur.

Further, the adhesion of the cast film layer 7 is 100 kPa or less at 200 ° C, preferably 50 kPa, and more preferably 30 kPa or less. This adhesion is the peak of the adhesion measured by the probe test. When the adhesive force of the cast film layer 7 exceeds 100 kPa at 200 ° C, it tends to adhere to the chuck when heated in a gas etching process or the like.

Further, the adhesion of the cast film layer 7 is preferably 20 kPa or less at 25 °C. If the adhesion of the cast film layer 7 exceeds 20 kPa at 25 ° C, it will not be easily peeled off from the chuck at normal temperature. Also, sticking may occur when the adhesive tape is rolled up.

The resin film layer 9 is not particularly limited, but examples of the resin used include polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, and ethylene vinyl acetate copolymerization. a homopolymer or copolymer of an α-olefin such as an ethylene-acrylic acid copolymer or an ionic polymer or a mixture thereof, polyethylene terephthalate, polycarbonate, polymethyl methacrylate or the like A thermoplastic elastomer such as an engineering plastic, a polyurethane, a styrene-ethylene-butylene or a pentene copolymer.

The thickness of the base film 3 is preferably 50 to 200 μm .

Further, when the base film 3 is a laminate of the resin film layer 9 and the cast film layer 7, the thickness of the cast film layer 7 is preferably 5 to 100 μm , more preferably 5 to 50 μm .

When the base film is formed only by the cast film layer 7, the thickness of the cast film layer 7 is preferably 50 to 200 μm , more preferably 50 to 100 μm .

Although the thickness of the resin film layer 9 is not particularly limited, it is usually in the range of 50 to 150 μm .

The cast film layer 7 is preferably composed of a composition coated with an acrylic copolymer or a polyester resin, and further cured by a hardener or radiation. Compared with the stretch film which is formed by the borrowing method and which is thinned by the stretching process, the cast film layer 7 formed by brushing has less residual stress, and is less heat-shrinked when exposed to high temperature. Further, the cast film layer 7 of the present embodiment has a three-dimensional mesh structure due to cross-linking, and the adhesive force at 200 ° C is small, so that it is not fused to the chuck when exposed to a high temperature.

Further, the breaking strength of the adhesive tapes 1 and 1a for semiconductor wafer protection is preferably 0.5 N/mm or more, and the elongation at break is preferably 200% or more. Having the above characteristics, that is, not causing damage when attaching and peeling off the semiconductor wafer Cracking and other issues.

(resin constituting the cast film layer)

The cast film layer 7 is formed of a hardened resin, in particular, a resin obtained by hardening an acrylic copolymer or a polyester resin. The acrylic copolymer or the polyester resin is not particularly limited, and an energy ray-curable resin, a hardener-curable resin, a thermosetting resin, or the like can be used, and an energy ray-curable resin or a hardener-curable resin is preferably used. When an energy ray-curable resin is used, the resin is cured by irradiating an energy ray after application. When a hardener hardening type resin is used, a crosslinking agent is added to the resin, and after being applied and dried, it is aged and cured. When a thermosetting resin is used, it is heated after coating to harden the resin.

In the case of laminating the cast film layer 7 and the resin film layer 9, a method of applying a curing resin to the resin film layer 9 and curing the film, and a method of adhering the cured film by an adhesive or the like may be mentioned. When the unlaminated cast film layer 7 is formed, the curable resin is applied onto the peelable film, and then cured, and then peeled off from the film to obtain a cast film layer 7.

(acrylic copolymer)

The acrylic copolymer for forming the cast film layer 7 is not particularly limited. For example, when an energy ray-curable resin is used, it may be composed of an acrylic adhesive and an energy ray polymerizable compound as a main component. The acrylic adhesive and the energy ray polymerizable compound can be specifically used as described below.

The component of the acrylic adhesive is a (meth)acrylic copolymer and a curing agent. (meth)acrylic copolymers may be exemplified by (meth) propyl The enoate is a copolymer of a copolymer constituent unit, a copolymer of a (meth) acrylate and a functional monomer, a mixture of the copolymers, and the like. The molecular weight of the copolymers is preferably a low molecular weight having a weight average molecular weight of about 10,000 to 200,000 in terms of ductility of the base film.

Further, the curing agent is used for reacting with a functional group contained in the (meth)acrylic copolymer to adjust the adhesion and cohesion. For example, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)toluene, 1,3- An epoxy compound containing two or more epoxy groups in a molecule such as bis(N,N-diglycidylaminomethyl)benzene, N,N,N,N'-tetraglycidyl-m-xylylenediamine or the like 2,4-diisocyanate, phenyl 2,6-diisocyanate, 1,3 diisocyanate, 1,4 diisocyanate, diphenyl An isocyanate compound having two or more isocyanate groups in a molecule such as methyl-4,4-diisocyanate, tetramethylol-tris-β-aziridine propionate, or trimethylol -Tri-β-aziridine propionate, trimethylolpropane-tri-β-aziridine propionate, trimethylolpropane-tri-β-(2-methylaziridine) An aziridine-based compound containing two or more aziridine groups in a molecule such as a propionate. The amount of the curing agent to be added can be adjusted in accordance with the desired adhesive strength, and it is appropriate to add 0.1 to 5.0 parts by mass to 100 parts by mass of the (meth)acrylic copolymer.

Further, when a hardener-curable resin is used, it is preferable to add an equivalent amount to a functional group reactive with a hardener in a (meth)acrylic copolymer in order to suppress adhesion and ensure strength and elongation as a film. It is appropriate to add a hardener such as 2.0 to 30 parts by mass to 100 parts by mass of the (meth)acrylic copolymer.

The energy ray-curable resin is generally adhered to the aforementioned acrylic The agent and the energy ray polymerizable compound are mainly composed of a component. As the energy ray-polymerizable compound, a low molecular weight compound containing at least two photopolymerizable carbon-carbon double bonds in a molecule which can be three-dimensionally networked by irradiation with ultraviolet rays is widely used. Specifically, trimethylolpropane triacrylate, tetramethylol methane tetraacrylate, neopentyl alcohol triacrylate, neopentyl alcohol tetraacrylate, dipentaerythritol monohydroxypentaacrylic acid can be widely used. Ester, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, 1,6 hexanediol diacrylate, polyethylene glycol diacrylate, and oligoester acrylate.

Further, the acrylic adhesive may be an urethane acrylate oligomer in addition to the above acrylate compound. The urethane acrylate oligomer is a polyvalent alcohol compound such as a polyester type or a polyether type and a polyvalent isocyanate compound (such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-two). a terminal isocyanate urethane prepolymer obtained by reacting toluene diisocyanate, 1,4-dimethylbenzene diisocyanate, diphenylmethyl 4,4-diisocyanate or the like to obtain a hydroxyl group-containing acrylate or methacrylate (such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate, etc. ) It is made by reacting with it.

The blending ratio of the acrylic adhesive to the energy ray-polymerizable compound in the energy ray-curable resin is 50 to 200 parts by mass, and 50 to 150 parts by mass, based on 100 parts by mass of the acrylic adhesive. The range is better. Within the range of the above-mentioned blending ratio, the adhesion of the energy ray-curable resin can be greatly reduced after the energy ray irradiation.

Further, the energy ray-curable resin may also be an acrylic adhesive itself. As the energy ray-polymerizable acrylate copolymer, the energy ray-polymerizable compound is blended with the acrylic adhesive as above.

Further, when the energy ray-curable resin is polymerized by an energy ray, a photopolymerization initiator such as benzoin isopropyl ether, benzoin isobutyl ether, diphenyl ketone, mischidone, chlorothioxanthone, benzyl group may be used in combination. Methyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenylpropane, and the like. By adding at least one of these to the energy ray-curable resin, the polymerization reaction can be carried out efficiently. In addition, the so-called energy line means free energy rays such as ultraviolet rays or electron beams.

(polyester resin)

The polyester resin for forming the cast film layer 7 is not particularly limited. For example, when a hardener-hardening resin is used, the hardener-curable polyester resin composition and the hardener are mainly composed. .

The hardener-curable polyester resin composition is a composition containing a polyester resin containing a functional group reactive with a hardener, and a hydroxyl group-containing polyester polyol can be suitably used.

Further, the hardener is used for reacting with a functional group contained in the hardener-curable polyester resin composition to adjust the adhesion and cohesion. An isocyanate compound containing two or more isocyanate groups in the above molecule can be suitably used.

<Adhesive layer>

The adhesive layer 5 can be formed by applying an adhesive to the base film 3. The adhesive layer 5 constituting the adhesive tape 1 for semiconductor wafer protection of the present embodiment has a retentive property of not being peeled off from the wafer during the gas etching process. can. Also, it is desirable to have less outgassing to avoid contamination of the wafer and device during heating.

In particular, the adhesion of the adhesive layer 5 before the irradiation of the energy ray or the like is preferably 50 to 400 kPa at 25 °C. The adhesion described above avoids peeling between the semiconductor wafer and the wafer of the adhesive.

In the present embodiment, the composition of the adhesive constituting the adhesive layer 5 is not particularly limited. However, in order to improve the peeling property, it is preferable to have energy ray curability, and it is preferable to be a material which can be easily peeled off from the wafer 21 after curing. The energy ray-curable adhesive may be composed of, for example, an acrylic adhesive and an energy ray polymerizable compound used as the main component of the cast film layer 7 . When an energy ray-curable adhesive is used, energy ray hardening may be applied before the gas etching process in order to improve heat resistance.

(use)

The adhesive tape 1 for semiconductor wafer protection of the present embodiment can be applied to an etching process for performing gas on a wafer sliced by a stealth dicing process.

(gas etching procedure)

The method of using the adhesive tape 1 for protecting a semiconductor wafer according to the present embodiment when applied to a gas etching process will be described with reference to FIG. 2 .

2 is a cross-sectional view showing a gas etching process for etching a wafer 11 in which a semiconductor wafer has been sliced by an etching gas 13 by a stealth dicing process. As shown in FIG. 2, a plurality of wafers 11 on which a semiconductor wafer has been sliced by a stealth dicing process are fixed to an adhesive tape for protecting a semiconductor wafer fixed to the ring frame 15. Moreover, the wafer 11 has been held by the chuck 17. Then, the etching gas 13 is irradiated, and the exposed face of the wafer 11 is etched.

The gas etching process can remove the modified field formed by the laser light remaining on the wafer dicing surface. The field of modification has been easily broken, so if the field of modification remains on the wafer 11, the wafer 11 will begin to rupture from the field of modification. The bending strength of the wafer 11 can be improved by removing the modified region and the uneven portion of the surface of the wafer 11. The gas etching is exemplified by a method of blowing a chlorine trifluoride (ClF ₃ ) gas heated to 200 ° C at a pressure of 0.3 to 2.0 MPa in a treatment chamber which has been depressurized to about 1 kPa.

At this time, the semiconductor wafer protective adhesive tape 1 is heated by irradiating the heated etching gas 13 or chemical reaction between the etching gas 13 and the wafer 11. Although the portion contacting the chuck 17 is cooled by circulating cooling water into the chuck 17, but the portion where the chuck 17 is not contacted and the heat generation is greater than the cooling capacity, the adhesive tape 1 for semiconductor wafer protection may be heated to about 200 ° C. .

(Effect of this embodiment)

In the present embodiment, even if the casting layer 7 of the contact chuck 17 is heated to 200 ° C and the adhesive force is still below a predetermined value, the adhesive tape 1 for semiconductor wafer protection of the present embodiment can be gas-etched without being fused to On the chuck 17.

Further, in the present embodiment, since the base film 3 is provided with the cast film layer 7, the heat shrinkage rate of the adhesive tape for semiconductor wafer protection is small, and the wafer positional deviation and wafer contact can be avoided in the gas etching process. .

In particular, in the present embodiment, when the base film is formed of only the cast film layer, the heat shrinkage rate of the adhesive tape for semiconductor wafer protection is smaller.

[Examples]

Next, in order to clarify the effects of the present embodiment, the examples and comparative examples will be described in detail, but the present invention is not limited to the examples.

[Production of Adhesive Tape for Semiconductor Wafer Protection]

(1) Fabrication of substrate film

(Laminated film of cast film A and resin film A)

A vinyl methacrylate (EMMA) resin "ACRYFT WD201 (trade name)" produced by Sumitomo Chemical Co., Ltd. was used, and a resin film A having a thickness of 100 μm was formed by a T-die method.

The ultraviolet curable acrylic copolymer A is applied onto a release film and dried to a thickness of 30 μm , and then the resin film A is bonded thereto and cured by irradiation with ultraviolet rays to obtain a total thickness of 130 μ. A laminated film of resin film A and cast film A of m.

The composition of the ultraviolet curable acrylic copolymer composition A is as follows.

The above acrylate copolymer and radiation polymerizable compound are as follows.

Acrylate copolymer: copolymerized 2-ethylhexyl acrylate, methacrylate, 2-hydroxy acrylate A copolymer having a weight average molecular weight of 100,000 and a glass transition temperature of -10 ° C.

Radiation-polymerizable compound: an epoxy acrylate oligomer having a weight average molecular weight of 1,100.

(cast film B)

The hardener-curable polyester resin composition is applied onto the release film and dried, and after bonding with other release film, it is aged for one week, and after hardening, it is peeled off from the release film to obtain a film shape. Cast film B. The thickness of the cast film B after drying was 70 μm .

The composition of the hardener-curable polyester resin composition is as follows.

(Resin film B)

A 100 μm polyethylene terephthalate film (produced by Teijin DuPont Films, G2: trade name) was used as the resin film B.

(2) Preparation of Adhesive Composition A

To 400 g of toluene in a solvent, 446.5 g of 2-ethylhexyl acrylate, 45 g of methyl methacrylate, 3.4 g of methacrylic acid, and 0.5 g of benzoyl peroxide as a polymerization initiator were dropped in 2 hours. The mixed solution was simultaneously subjected to a reaction at a temperature of 100 ° C for 4 hours to obtain a solution of the functional group-containing polymer (2). Next, 5.1 g of 2-hydroxyethyl methacrylate and 0.1 g of hydroquinone as a polymerization inhibitor were added to the polymer (2) as a photopolymerizable carbon-carbon double The compound (1) having a bond and a functional group is reacted at 120 ° C for 6 hours, and then neutralized with acetic acid to prepare a solution of the compound (A). 1 part by mass of a polyisocyanate (Nippon Polyurethane Co., Ltd.: CORONATEL) (B) and a photopolymerization initiator (Irgacure 184 manufactured by Nihon Ciba-Geigy Co., Ltd.), based on 100 parts by mass of the compound (A) in the solution of the compound (A). 0.5 parts by mass of the compound (A) was added and mixed to prepare an acrylic energy ray-curable adhesive composition A.

<First Embodiment>

The prepared adhesive composition A is applied to the resin film A side of the film formed by laminating the cast film A and the resin film A, and dried to form an adhesive tape for protecting a semiconductor wafer.

<Second embodiment>

The adhesive composition A is applied to the cast film B and dried to form an adhesive tape for protecting a semiconductor wafer.

<First Comparative Example>

The adhesive composition A is applied to the resin film A and dried to form an adhesive tape for protecting a semiconductor wafer.

<Second Comparative Example>

The adhesive composition A is applied to the resin film B and dried to form an adhesive tape for protecting a semiconductor wafer.

[Physical properties and evaluation of adhesive tape for semiconductor wafer protection]

(1) Determination of adhesion

The measurement was carried out using a viscosity tester TAC-II of RHESCA Corporation. In the measurement mode, the pressure probe is used to set the pressure value, and the pressure is maintained. Constant Load that continues to control until the set time elapses. After peeling off the separator, the substrate film was placed on the carrier with the side on which the adhesive layer was not formed facing upward, and was contacted with a probe made of SUS304 having a diameter of 3.0 mm from the upper side. The probe was brought into contact with the measurement sample at a speed of 30 mm/min, a contact load of 100 gf, and a contact time of 1 second. Then, the probe was peeled upward at a peeling speed of 600 mm/min, and the force required for the peeling was measured, and the peak was used as the adhesive force. The adhesion is made to correspond to the temperature to be measured, and the probe and the sheet temperature such as the adhesion at 200 ° C are set to 200 ° C.

(2) Evaluation of gas etching procedures

A mirror wafer with a diameter of 6 inches and a thickness of 100 μm is bonded to the adhesive tape for semiconductor wafer protection, and is cut from the wafer surface by 10 mm square (the depth of the substrate is 20 μm ) into 6 wafers. Thereafter, in the vacuum processing chamber, the adhesive tape for protecting the semiconductor wafer was adsorbed on the chuck, and gas etching of ClF ₃ was performed for 30 seconds. At this time, warm water of 70 ° C was poured into the chuck to cool the adhesive tape for the semiconductor wafer and the wafer. After the procedure, it is evaluated whether the adhesive tape can be easily peeled off from the chuck.

The meanings of ○ and × in the table are as follows.

"○": After the gas etching process, the adhesive tape can be easily peeled off from the chuck.

"X": After the gas etching process, the adhesive tape cannot be easily peeled off from the chuck, or the adhesive tape is broken and melted.

(3) Displacement evaluation of the wafer

Gas etching evaluation has been evaluated as a process that can be processed and stripped from the chuck, and the wafer spacing caused by the cutting of the five parts by the optical microscope is confirmed by the offset in the gas etching process. For example, the offset is 3 μm with respect to the slit width of 25 μm due to the cutting, and the interval between wafers after the gas etching process is 22 μm . The deviation of all the parts within ±1μm was rated as ◎, and the deviation of all parts within ±2.5μm was rated as ○, and even if only one part of the 5 parts was shifted by ±2.5μm or more Will also be rated as ×.

(4) Breaking strength, elongation at break

A test piece was prepared by punching through an adhesive tape in accordance with the No. 1 dumbbell shape (JIS K 6301), and then measured using a tensile tester (JIS B 7721). After the test piece was recorded with a 40 mm mark, the tensile tester was used to measure the load (tensile strength) and elongation at the time of dividing between the lines. However, the stretching speed was 300 mm/min.

As shown in Table 1, in the adhesive tape for protecting a semiconductor wafer of the first to second embodiments, the side where the adhesive layer is not formed is the cast film layer A to B, and the adhesive force of the outermost layer is 100 kPa even at 200 ° C. Hereinafter, the base film of the adhesive tape does not adhere to the chuck in the gas etching process.

In particular, the substrate film of the second embodiment is only a cast film, so that the heat is less contracted, and the wafer displacement in the gas etching process is less.

In the first comparative example, since the outermost layer on the side of the base film on which the adhesive is not formed is the resin film A, the base film of the adhesive tape is fused to the chuck in the gas etching process. After the gas etching process, it is difficult to strip the substrate film from the chuck.

In the second comparative example, the adhesion of the outermost layer on the side where the adhesive film is not formed on the base film is 100 kPa or less even at 200 ° C. However, under the influence of the heating in the etching process, the film is formed by the film. Residual stress shrinks and causes the adhesive tape to float from the chuck without being cooled by the chuck, so the discoloration of the wafer and the deterioration of the adhesive have been found.

The preferred embodiments of the present invention have been described above with reference to the drawings, but the invention is not limited thereto. Those skilled in the art can devise various modifications and alterations within the scope of the technical idea disclosed in the present disclosure, and of course, should be construed as falling within the technical scope of the present invention.

1, 1a‧‧‧Adhesive tape for semiconductor wafer protection

3‧‧‧Substrate film

5‧‧‧Adhesive layer

7‧‧‧ cast film layer

9‧‧‧ resin film layer

Claims (6)

An adhesive tape for protecting a semiconductor wafer, comprising: a base film and an adhesive layer formed on one surface of the base film, wherein the base film has an outermost layer on a side where the adhesive layer is not formed The cast film layer containing the hardened resin is set to have a speed of 30 mm/min when the probe made of SUS304 having a diameter of 3.0 mm is brought into contact with the measurement sample, a contact load of 980 mN (100 gf), and a contact time of 1 second. The peak of the adhesion of the cast film layer measured by the probe test when the probe was peeled upward at a peeling speed of 600 mm/min was 100 kPa or less at 200 °C. The adhesive tape for protecting a semiconductor wafer according to claim 1, wherein the substrate film is composed only of a cast film layer. The adhesive tape for protecting a semiconductor wafer according to claim 1, wherein the cast film layer contains a hardened acrylic copolymer or a polyester resin. The adhesive tape for protecting a semiconductor wafer according to claim 1, wherein the cast film layer is composed of an acrylic copolymer which has been hardened by a curing agent or radiation. The adhesive tape for protecting a semiconductor wafer according to claim 1, wherein the breaking strength is 0.5 N/mm or more and the elongation at break is 200% or more. The adhesive tape for protecting a semiconductor wafer according to claim 1, wherein a probe made of SUS304 having a diameter of 3.0 mm is brought into contact with the measurement sample at a speed of 30 mm/min, a contact load of 980 mN (100 gf), and a contact time of 1 In the second condition, the probe is stripped upward at a peeling speed of 600 mm/min. The peak of the adhesion of the aforementioned adhesive layer measured by the probe test was 50 to 400 kPa at 25 °C.