JP2007002218A - Base film for dicing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base film for dicing, wherein transparency is excellent and the recovery of a wasted dicing film to a rack can be conducted quickly and easily. <P>SOLUTION: The base film for dicing comprises a styrenic elastomer resin composition (SE resin composition) comprising (i) 100-20 wt.% of a styrenic elastomer resin (SE resin A) having a glass transition point of 40-60°C and 70-90 wt.% of a styrene ratio and (ii) 0-80 wt.% of a styrenic elastomer resin (SE resin B) having a glass transition point of not higher than 30°C and 7-80 wt.% of a styrene ratio. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dicing film for fixing a semiconductor wafer or the like when the semiconductor wafer or the like is diced into chips.

  The semiconductor wafer is made in advance with a large area, then diced into chips (cut and separated), and transferred to the mounting process. In the dicing, a dicing film is used for fixing the semiconductor wafer.

  The dicing film is basically composed of an adhesive layer for fixing the semiconductor wafer and a resin layer (a substrate film for dicing) that receives the cutting of the dicing cutter. As the substrate film for dicing, a polyolefin film or a polyvinyl chloride film is generally used. However, the polyvinyl chloride film is in decline due to environmental problems.

  In addition, after the semiconductor wafer attached to the adhesive layer of the dicing film is diced into chips, the dicing film is uniformly expanded (expanded) in the vertical and horizontal directions in order to facilitate the pick-up process. A process of spreading the film uniformly is required. Therefore, the dicing film is required to have uniform and smooth expandability after dicing. Moreover, with the recent further downsizing of wafers (for example, 10 × 10 mm is reduced to 1 × 1 mm), there is a substrate film for dicing that can be expanded uniformly and smoothly without tearing or cutting. It is desired.

  The cut semiconductor wafer chip is fixed to a dicing film, and in this state, the semiconductor wafer chip is visually inspected for defective parts such as chipping. In order to facilitate this visual inspection, the substrate film for dicing is required to have high transparency.

  After dicing, the dicing film is expanded so that the semiconductor wafer chip can be easily picked up, a certain gap is formed in the chip, and the chip is picked up by the picker, and the process is completed. The used dicing film is contracted by heating at a predetermined temperature (warm air) and collected and stored in a film recovery container (rack). At this time, the dicing film is required to be a film that can be heated and shrunk to at least a size that can be easily stored in a rack in consideration of the recoverability of the film.

  However, since the known dicing film has a small shrinkage ratio due to heating, it is not easy to collect it in the rack. In addition, when the wafer is cut to a smaller size, the expansion of the film becomes large, so that the recovery of the film becomes even more difficult, and in reality, recovery by this heating is impossible. Therefore, a dicing film having a characteristic of restoring shrinkage at a lower temperature is desired.

  By the way, a dicing film is usually rolled, manufactured, stored and transported. For this reason, when the blocking between films occurs, the quality deteriorates. That is, even if it has excellent quality as a dicing film, it is difficult to provide a high-quality dicing film unless the problem due to blocking is solved.

  The main object of the present invention is to provide a substrate film for dicing that is excellent in transparency and that can quickly and easily collect used dicing film in a rack (hereinafter referred to as rack recoverability). Objective. The rack is a name used in the industry, and is also called a sipper or a case.

  As a result of intensive studies to solve the above problems, the present inventor has (i) a styrene elastomer resin 100 having a glass transition temperature (Tg) of 40 to 60 ° C. and a styrene ratio of 70 to 90% by weight. Dicing comprising -20% by weight and (ii) a styrene-based elastomer resin composition comprising 0-80% by weight of a styrene-based elastomer resin having a glass transition temperature (Tg) of 30 ° C. or less and a styrene ratio of 7-80% by weight It has been found that the substrate film for use has high transparency and rack recoverability. Based on this knowledge, further studies have been made and the present invention has been completed.

  That is, the present invention provides the following substrate film for dicing.

  Item 1. (I) 100-20% by weight of a styrene elastomer resin (SE resin A) having a glass transition temperature of 40-60 ° C and a styrene ratio of 70-90% by weight, and (ii) a glass transition temperature of 30 ° C or less. A substrate film for dicing comprising a styrene elastomer resin composition (SE resin composition) comprising 0 to 80 wt% of a styrene elastomer resin (SE resin B) having a styrene ratio of 7 to 80 wt%.

  Item 2. Item 2. The substrate film for dicing according to Item 1, wherein the styrene ratio of the entire styrene-based elastomer resin composition is 40 to 90% by weight.

  Item 3. Item 3. The substrate film for dicing according to Item 1 or 2, comprising a multilayer structure having at least one layer containing the styrenic elastomer resin composition.

  Item 4. Item 4. The substrate film for dicing according to any one of Items 1 to 3, further comprising an adhesive layer on the substrate film for dicing.

Hereinafter, the present invention will be described in detail.
I. Dicing Substrate Film The dicing substrate film of the present invention is (i) a styrene elastomer resin having a glass transition temperature of 40 to 60 ° C. and a styrene ratio of 70 to 90% by weight (hereinafter also referred to as “SE resin A”). 100 to 20 wt%, and (ii) 0 to 80 wt% of a styrene elastomer resin (hereinafter also referred to as “SE resin B”) having a glass transition temperature of 30 ° C. or less and a styrene ratio of 7 to 80 wt%. A styrene elastomer resin composition (hereinafter also referred to as “SE resin composition”) is included.

  The SE resin composition contained in the dicing substrate film of the present invention will be described. The SE resin composition is composed of SE resin A and SE resin B, which are hydrogenated products (hereinafter referred to as “hydrogenated copolymers”) of copolymers of styrene monomers and diene monomers. Call).

  Examples of the styrene monomer include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N, N-dimethyl-p-aminoethylstyrene, N, N-diethyl- Examples thereof include p-aminoethylstyrene, and these may be used alone or in combination of two or more. Styrene is particularly preferred.

  The diene monomer is a diolefin having a pair of conjugated double bonds, such as 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1. 1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, etc., with 1,3-butadiene and isoprene being particularly common. These may be used alone or in combination of two or more. In particular, butadiene is preferred.

  The hydrogenated copolymer is a hydrogenated random copolymer of a styrene monomer and a diene monomer (hereinafter also referred to as “hydrogenated random copolymer”), and a styrene monomer. And a hydrogenated product of a block copolymer of a monomer and a diene monomer (hereinafter also referred to as “hydrogenated block copolymer”).

Here, specific examples of the hydrogenated random copolymer has the _{formula: -CH (C 6 H 5)} CH 2 - and styrene-based monomer unit represented by the _{formula: -CH 2 CH 2 CH 2 CH} 2 - ethylene unit represented by the _{formula: -CH (C 2 H 5)} CH 2 - hydrogenated butylene units are randomly bonded represented by random copolymers.

  The hydrogenated random copolymer can be produced, for example, by the method described in JP-A No. 2004-59741 or according thereto.

  The hydrogenated block copolymer has a block segment derived from a styrene monomer at one or both ends of the copolymer, and further has a block segment derived from a diene monomer, or these Blended ones are listed.

The hydrogenated block copolymer, for example, to one end of the copolymer, the _{formula: -CH (C 6 H 5)} CH 2 - has a block segment derived from styrene monomers represented by the therein The block segment includes an ethylene unit represented by the formula: —CH ₂ CH ₂ CH ₂ CH ₂ — and / or a butylene unit represented by the formula: —CH (C ₂ H ₅ ) CH ₂ —. And a hydrogenated block copolymer having a segment containing an ethylene unit represented by the formula: —CH ₂ CH ₂ CH ₂ CH ₂ — at the other end of the copolymer. As a specific example of the hydrogenated block copolymer as described above, SEBC is exemplified.

As another hydrogenated block copolymer, for example, it has a block segment derived from a styrenic monomer at both ends of the copolymer, and in the middle thereof, the formula: —CH ₂ CH ₂ CH ₂ CH ₂ - ethylene units represented by, and / or the _{formula: -CH (C 2 H 5)} CH 2 - hydrogenated block copolymer having a block segment comprising a butylene unit represented by like. As a specific example of the hydrogenated block copolymer as described above, SEBS is exemplified.

  Among such hydrogenated copolymers, a hydrogenated random copolymer is preferable from the viewpoint of flexibility, transparency, and the like.

  SE resin A is such a hydrogenated copolymer, and the content of styrene monomer units (styrene ratio) is usually 70 to 90% by weight, preferably 70 to 80% by weight, more preferably 75 to 75%. The content (diene ratio) of the diene monomer unit is usually 30 to 10% by weight, preferably 30 to 20% by weight, and more preferably 25 to 20% by weight. The content of styrene monomer units is measured using an ultraviolet spectrophotometer or a nuclear magnetic resonance apparatus (NMR), and the content of diene monomer units is measured using a nuclear magnetic resonance apparatus (NMR). be able to. Moreover, the glass transition temperature (Tg) of SE resin A is about 40-60 degreeC, Preferably it is about 40-55 degreeC. The glass transition temperature (Tg) is measured by differential scanning calorimetry (DSC method). Moreover, the weight average molecular weight (Mw) of SE resin A can be measured using commercially available standard gel permeation chromatography (GPC), for example, about 100,000 to 500,000, preferably about 150,000 to 300,000. .

  SE resin B is such a hydrogenated copolymer, and the content of styrene monomer units (styrene ratio) is usually 7 to 80% by weight, preferably 10 to 70% by weight, more preferably. The content of the diene monomer units (diene ratio) is usually 20 to 93% by weight, preferably 30 to 90% by weight, more preferably 30 to 80% by weight. . The glass transition temperature (Tg) of the SE resin B is 30 ° C. or less, preferably about −40 to 20 ° C. Moreover, the weight average molecular weight (Mw) of SE resin B is about 100,000 to 500,000, preferably about 150,000 to 300,000 as measured by GPC method.

  Furthermore, the SE resin composition comprising SE resin A and SE resin B preferably has a styrene ratio of 40 to 90% by weight, more preferably 50 to 80% by weight, in the entire composition. This is because in this range, expandability and shrinkage recovery properties are improved.

  The SE resin A or SE resin B used in the present invention is a hydrogenated product obtained by hydrogenating a copolymer composed of a styrene monomer and a diene monomer by a known method (for example, a nickel catalyst). is there. This is because it becomes a more stable resin excellent in heat resistance, chemical resistance, durability and the like. The hydrogenation rate of SE resin A or SE resin B is 85% or more, preferably 90% or more, more preferably 95% or more of the double bond based on the conjugated diene compound in the copolymer. This hydrogenation rate can be measured using a nuclear magnetic resonance apparatus (NMR).

  In the SE resin composition of the present invention, the content ratio of SE resin A and SE resin B is 100 to 20% by weight of SE resin A and 0 to 80% by weight of SE resin B, as described above. SE resin A is 90 to 30% by weight, SE resin B is 10 to 70% by weight, more preferably SE resin A is 80 to 40% by weight, and SE resin B is 20 to 60% by weight. If it is this range, it will become a film excellent in transparency and rack recoverability. When SE resin A is less than 20% by weight and SE resin B exceeds 80% by weight, the restorability due to shrinkage is undesirably lowered.

  In the present invention, the copolymer before hydrogenation is, for example, a styrene monomer and a diene monomer in a hydrocarbon solvent such as n-hexane, an organic alkali metal compound (n-butyllithium), etc. Can be produced by anionic living polymerization using the initiator.

  The copolymer of a styrene monomer and a diene monomer can be adjusted by employing a known method, for example, N, N, N ′, N′-tetramethylethylenediamine as a regulator. A tertiary amine compound or an ether compound can be added. The method of copolymerization may be batch polymerization or continuous polymerization. The polymerization temperature is generally 0 ° C. to 180 ° C., preferably 30 ° C. to 150 ° C. Although the time required for the polymerization varies depending on the conditions, it is usually within 48 hours, particularly preferably 0.1 to 10 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited as long as the polymerization pressure is in a range sufficient to maintain the monomer and solvent in a liquid phase within the above polymerization temperature range. The random copolymer and the block copolymer can be easily produced by a known method, for example, by controlling the timing of addition of raw materials. For example, in the case of a block copolymer, each segment of a styrene monomer and a diene monomer may be polymerized stepwise, and in the case of a random copolymer, a styrene monomer and A diene monomer may be copolymerized at once.

  By hydrogenating the copolymer obtained above, the hydrogenated copolymer of the present invention is obtained. The hydrogenation catalyst is not particularly limited and is conventionally known. For example, (1) supported heterogeneity in which a metal such as Ni, Pt, Pd, Ru is supported on carbon, silica, alumina, diatomaceous earth, or the like. (2) so-called Ziegler-type hydrogenation catalysts using (2) organic acid salts such as Ni, Co, Fe, Cr, transition metal salts such as acetylacetone salts and reducing agents such as organic aluminum, and (3) Ti Homogeneous hydrogenation catalysts such as so-called organometallic complexes such as organometallic compounds such as Ru, Rh and Zr are used.

  The hydrogenation reaction is generally carried out in a temperature range of about 30 to 150 ° C. The pressure of hydrogen used for the hydrogenation reaction is recommended to be 0.1 to 15 MPa. The hydrogenation reaction time is usually about 3 minutes to 10 hours. The hydrogenation reaction can be any of a batch process, a continuous process, or a combination thereof. Thus, the hydrogenated copolymer (SE resin) of the present invention is produced. Stabilizers such as various phenol stabilizers, phosphorus stabilizers, sulfur stabilizers and amine stabilizers can be added to the hydrogenated copolymer of the present invention.

  The “SE resin A” and the “SE resin B” can be separately prepared by adjusting the content of the styrene monomer, the content of the diene monomer, and the like in the above range, This is possible by appropriately selecting the manufacturing conditions.

  Since the substrate film for dicing of the present invention has the SE resin composition composed of SE resin A and SE resin B at a predetermined ratio as described above, it has high transparency and excellent heat shrinkability. Therefore, the rack recoverability is excellent.

  The transparency (haze value; JIS-Z-8741) of the substrate film for dicing of the present invention is about 0.5 to 15%, preferably about 0.8 to 10%. This facilitates visual inspection of the semiconductor wafer chip after dicing.

  In addition, the substrate film for dicing of the present invention has excellent warm air restoring properties (that is, heat shrinkability). Specifically, the restoration rate is 95% or higher, preferably 98% or higher, more preferably 100% or higher when the load after film expansion (expanding) is removed and hot air of 60 ° C. is blown for 10 seconds. Therefore, contraction by heating (warm air) is performed quickly, and further contracts to a size that can be easily stored in a rack. In other words, it can be restored to the size of the film before expansion. In addition, since it can be restored in a relatively short heating time of about 5 to 20 seconds under relatively low heating conditions of about 50 to 80 ° C., it is possible to perform processing quickly and at low cost. The measurement of the restoration rate may be referred to the example section.

  In the conventional substrate film for dicing made of polyolefin or the like, the warm air restoration property is 75% or less, and considering that it is not satisfactory, the warm air restoration property of the dicing substrate film of the present invention is remarkable. It is.

  In addition, even when the film is greatly expanded (for example, about 1.05 to 2.00 times), the above-described high hot air recovery property (recovery rate is 95% or more) is exhibited. Excellent rack recoverability of film when cut into small size.

  The substrate film for dicing according to the present invention also has excellent blocking resistance.

  The layer thickness of the substrate film for dicing according to the present invention should be at least thicker than the cut depth of the dicer and can be easily wound in a roll shape, for example, about 80 to 300 μm, preferably 80. It may be about ˜250 μm.

  As described above, the single-layer dicing substrate film containing the SE resin composition has been described, but it is also possible to laminate a plurality of same or different SE resin compositions into a multi-layer dicing substrate film. is there. Alternatively, a multi-layer substrate film for dicing in which another resin is laminated on the SE resin composition layer (single layer or multilayer) may be used as long as the effect of the film of the present invention is not adversely affected. Examples of other resins include polyolefin resins such as polyethylene resins, polypropylene resins, polymethylpentene resins, and cyclic olefin resins, and polyethylene resins are particularly preferable. In addition, all of multilayering of a film can be performed using a well-known method.

As a specific example of the substrate film for dicing having a multilayer structure, the following multilayer structure is exemplified.
SE resin composition layer / SE resin composition layer,
SE resin composition layer / SE resin composition layer / SE resin composition layer,
SE resin composition layer (including SE resin A only) / polyolefin resin layer,
SE resin A layer / SE resin B layer / SE resin A layer, or SE resin A layer / SE resin B layer / polyolefin-based resin layer.

  In addition, when two or more SE resin composition layers, SE resin A layers, and the like are included in the multilayer structure, the compositions thereof may be the same or different types.

  The total thickness of the substrate film for multi-layer dicing may be at least thicker than the cutting depth of the dicer and can be easily wound in a roll shape, for example, about 80 to 300 μm, preferably 80 to What is necessary is just about 250 micrometers. Among them, the total thickness of the SE resin composition layer, the SE resin A layer, and the SE resin B layer is 75 to 100%, preferably 85 to 100% of the total film thickness. Is preferable.

  The multilayer dicing substrate film containing the polyolefin resin as the outermost layer has a merit that the quality after film production is maintained because the blocking resistance is remarkably improved.

  The manufacturing method of the substrate film for dicing according to the present invention is as follows. The above-mentioned predetermined amounts of SE resin A and SE resin B are uniformly blended and dispersed by dry blending or melt-kneading. Next, the obtained mixture is supplied to a screw type extruder, extruded from a single-layer T die at 200 to 225 ° C., and cooled while passing through a cooling roll at 50 to 70 ° C. Take it unstretched.

  In the case of a substrate film for multilayer dicing, a multilayer coextrusion molding method is adopted. Specifically, the above-mentioned predetermined amounts of SE resin A and SE resin B are uniformly blended and dispersed by dry blending or melt kneading. Further, other resins are dry blended or melt kneaded to uniformly mix and disperse. Next, each obtained mixture is supplied to a screw type extruder, extruded from a multilayer T die at 200 to 225 ° C., and cooled while passing through a cooling roll at 50 to 70 ° C. Take it unstretched.

Here, the reason why the film is substantially unstretched is to effectively extend the film after dicing. This substantially non-stretching includes non-stretching or slight stretching that does not adversely affect the expansion of the dicing film. In general, the film may be pulled to such an extent that no sagging occurs during film take-up.
II. Dicing film The substrate film for dicing obtained as described above is coated with a known pressure-sensitive adhesive on the film to form a pressure-sensitive adhesive layer, and a release layer is further formed on the pressure-sensitive adhesive layer. A film is produced. This film is usually obtained in a rolled state cut into a tape shape.

  As the pressure-sensitive adhesive component used in the pressure-sensitive adhesive layer, known ones are used. For example, the pressure-sensitive adhesive component described in JP-A No. 5-21234 can be used. A known release layer is also used.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive. Specifically, the pressure-sensitive adhesive layer was selected from a homopolymer and a copolymer having (meth) acrylic acid ester as a main constituent monomer unit. Acrylic polymers, copolymers with other functional monomers, and mixtures of these polymers are used. For example, (meth) acrylic acid ester includes ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, Glycidyl acrylate, 2-hydroxyethyl acrylate and the like can be preferably used. The molecular weight of the acrylic polymer is 1.0 × 10 ^{5 to} 10.0 × 10 ⁵ , and preferably 4.0 × 10 ^{5 to} 8.0 × 10 ⁵ .

  In addition, by including a radiation polymerizable compound in the pressure-sensitive adhesive layer as described above, the adhesive strength can be reduced by irradiating the pressure-sensitive adhesive layer with radiation after the wafer is cut and separated. As such a radiation polymerizable compound, for example, a low molecular weight compound having at least two photopolymerizable carbon-carbon double bonds in a molecule that can be three-dimensionally reticulated by light irradiation is widely used (for example, JP JP-A-60-196,956, JP-A-60-223,139, etc.).

  Specifically, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and the like are used.

  Furthermore, in addition to the acrylate compounds as described above, urethane acrylate oligomers can also be used as the radiation polymerizable compound. The urethane acrylate oligomer is obtained by reacting an acrylate or methacrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound such as polyester type or polyether type with a polyvalent isocyanate compound. This urethane acrylate oligomer is a radiation polymerizable compound having at least one carbon-carbon double bond.

  Further, in the pressure-sensitive adhesive layer, in addition to the pressure-sensitive adhesive and the radiation-polymerizable compound as described above, a compound (such as a leuco dye) that is colored by radiation irradiation, a light-scattering inorganic compound powder, and abrasive grains, as necessary. (A particle size of about 0.5 to 100 μm), an isocyanate curing agent, a UV initiator, and the like can also be contained.

  When the pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive is provided as described above, acrylic is applied to the layer to be bonded to the dicing substrate film from the viewpoint of reduction of grinding dust and adhesion between the substrate film for dicing and the pressure-sensitive adhesive layer. It is preferable to contain a resin. As the acrylic resin, a soft acrylic resin is preferable in order to obtain a good hot air restoring property (restoration rate of 95% or more) of the dicing film. The soft acrylic resin preferably has a glass transition temperature (Tg) of about 40 to 70 ° C. and a durometer-A hardness of 40 to 95 ° C. As a specific example, a soft acrylic resin “Parapet SA” manufactured by Kuraray Co., Ltd. And the like are exemplified.

  When the substrate film for dicing is a single layer, the content of the acrylic resin contained in the substrate film for dicing is, for example, about 5 to 50 parts by weight with respect to 100 parts by weight of the SE resin composition in the single layer. It is preferable that about 5 to 30 parts by weight of an acrylic resin is included. If the content of the acrylic resin is too large, the transparency of the substrate film for dicing tends to be lowered, so the above range is preferable.

  When the substrate film for dicing is a multilayer, an acrylic resin may be contained in the layer in contact with the pressure-sensitive adhesive layer. Considering the transparency of the base film, the acrylic resin is about 5 to 65 parts by weight, preferably about 5 to 50 parts by weight, based on 100 parts by weight of the SE resin composition contained in the layer in contact with the pressure-sensitive adhesive layer. Is preferably included.

  The substrate film for dicing of the present invention is excellent in rack recoverability due to excellent transparency and high resilience by heat.

  Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples, but the present invention is not limited to these Examples.

Production Example 1 (SE resin B)
Continuous polymerization was carried out using a stirring device having an internal volume of 10 L and two jacketed tank reactors. From the bottom of the first reactor, a cyclohexane solution having a butadiene concentration of 24% by weight at a feeding rate of 4.51 L / hr and a cyclohexane solution having a styrene concentration of 24% by weight at a feeding rate of 5.97 L / hr, A cyclohexane solution prepared by adjusting the concentration of n-butyllithium to 0.077 g with respect to 100 g of monomer at a supply rate of 2.0 L / hr and further N, N, N ′, N′-tetramethylethylenediamine The cyclohexane solution was fed at a feed rate of 0.44 mole per mole of n-butyllithium, and continuously polymerized at 90 ° C. The reaction temperature was adjusted by the jacket temperature, the temperature near the bottom of the reactor was about 88 ° C., and the temperature near the top of the reactor was about 90 ° C. The average residence time in the polymerization reactor was about 45 minutes, the conversion of butadiene was almost 100%, and the conversion of styrene was 99%.

  The polymer solution from the first unit is supplied from the bottom of the second unit, and at the same time, a cyclohexane solution having a styrene concentration of 24% by weight is supplied to the bottom of the second unit at a supply rate of 2.38 L / hr. The polymer was continuously polymerized to obtain a random copolymer. The conversion rate of styrene at the second outlet was 98%.

  When the polymer obtained by continuous polymerization was analyzed using NMR, the styrene content was 65% by weight.

  Charge 1 liter of dried and purified cyclohexane to a nitrogen-substituted reaction vessel, add 100 mmol of bis (η5-cyclopentadienyl) titanium dichloride, and add n-hexane solution containing 200 mmol of trimethylaluminum with thorough stirring. Then, a hydrogenation catalyst used for the hydrogenation reaction was prepared by reacting at room temperature for about 3 days.

  Next, 100 ppm of the hydrogenation catalyst as Ti per 100 parts by weight of the polymer was added to the polymer obtained by continuous polymerization, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C.

  Methanol was then added, and then 0.3 parts by weight of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a stabilizer was added to 100 parts by weight of the polymer.

  The obtained hydrogenated copolymer had a hydrogenation rate of 99%, a weight average molecular weight of 190,000, and a molecular weight distribution of 1.4. The glass transition temperature (Tg) determined by DSC was 15 ° C. Table 1 shows the characteristics of the obtained hydrogenated polymer (corresponding to SE resin B).

Production Example 2 (SE Resin A)
A hydrogenated random polymer (corresponding to SE resin A) was produced in the same manner as in Production Example 1 except that the amount of styrene fed to the first group and the second group was changed. The styrene content was 75% by weight, the hydrogenation rate was 99%, the weight average molecular weight was 210,000, and the molecular weight distribution was 1.9. The glass transition temperature (Tg) determined by DSC was 50 ° C. The characteristics of the obtained hydrogenated polymer (corresponding to SE resin A) are shown in Table 1.

Production Example 3 (SE Resin B)
A cyclohexane solution (concentration: 20% by weight) containing 33.5 parts by mass of styrene was charged into an agitator and jacketed tank reactor having an internal volume of 10 L. Next, n-butyllithium and N, N, N ′, N′-tetramethylethylenediamine are added and polymerized at 70 ° C. for 1 hour, then a cyclohexane solution containing 33 parts by mass of butadiene is added and polymerized at 70 ° C. for 1 hour. Further, a cyclohexane solution containing 33.5 parts by mass of styrene was added and polymerized at 70 ° C. for 1 hour. The obtained copolymer was a block copolymer having an SBS structure having a styrene content of 65% by weight.

  Next, 100 ppm of the above hydrogenation catalyst as Ti per 100 parts by weight of the polymer was added to the obtained polymer, and a hydrogenation reaction was performed at a hydrogen pressure of 0.7 MPa and a temperature of 65 ° C. Equivalent). The obtained hydrogenated polymer had a hydrogenation rate of 98% and a weight average molecular weight of 170,000. Moreover, the glass transition temperature (Tg) calculated | required by DSC was -40 degreeC. Table 1 shows the characteristics of the obtained hydrogenated polymer (corresponding to SE resin B).

Example 1 (single layer film)
The hydrogenated copolymer obtained in Production Example 2 is supplied to a screw type extruder having a barrel temperature of 180 to 220 ° C., extruded from a single layer T die at 220 ° C., and cooled while passing through a 60 ° C. cooling roll. It solidified and wound up in an unstretched state to produce a substrate film for dicing according to the present invention.

  The thickness of the obtained substrate film for dicing was 80 μm, and the styrene ratio of the whole film was 75%.

Example 2 (single layer film)
50 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 50 parts by weight of the hydrogenated copolymer obtained in Production Example 1 are dry blended and supplied to a screw type extruder having a barrel temperature of 180 to 220 ° C. Then, it was extruded from a single layer T die at 220 ° C., cooled and solidified while passing through a 60 ° C. cooling roll, and wound up in an unstretched state to produce a substrate film for dicing according to the present invention.

  The thickness of the obtained substrate film for dicing was 80 μm, and the styrene ratio of the whole film was 70%.

Example 3 (single layer film)
80 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 20 parts by weight of the hydrogenated copolymer obtained in Production Example 3 are dry blended and supplied to a screw type extruder having a barrel temperature of 180 to 220 ° C. Then, it was extruded from a single layer T die at 220 ° C., cooled and solidified while passing through a 60 ° C. cooling roll, and wound up in an unstretched state to produce a substrate film for dicing according to the present invention.

  The thickness of the obtained substrate film for dicing was 80 μm, and the styrene ratio of the whole film was 73%.

Example 4 (single layer film)
30 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 70 parts by weight of the hydrogenated copolymer obtained in Production Example 1 were dry-blended and put into a screw extruder having a barrel temperature of 180 to 220 ° C. Then, it was extruded from a single layer T die at 220 ° C., cooled and solidified while passing through a 60 ° C. cooling roll, and wound up in an unstretched state to produce a substrate film for dicing according to the present invention.

  The thickness of the obtained substrate film for dicing was 80 μm, and the styrene ratio of the whole film was 68%.

Example 5 (single layer film)
Soft acrylic resin (manufactured by Kuraray Co., Ltd., SA-D, Tg = 60) with respect to 30 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 70 parts by weight of the hydrogenated copolymer obtained in Production Example 1. ~ 65 ° C) is dry blended, supplied to a screw type extruder having a barrel temperature of 180-220 ° C, extruded from a single layer T-die at 220 ° C, and cooled and solidified through a 60 ° C cooling roll. Then, the film was wound in an unstretched state to produce a substrate film for dicing according to the present invention.

  The thickness of the obtained substrate film for dicing was 80 μm, and the styrene ratio of the whole film was 52%.

  Further, it was confirmed that the obtained substrate film for dicing had sufficient adhesiveness with the pressure-sensitive adhesive layer when a pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive was provided thereon.

Example 6 (Multilayer film)
A resin obtained by dry blending 50 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 50 parts by weight of the hydrogenated copolymer obtained in Production Example 1 was used as a resin for the layer (A).

  A resin obtained by dry blending 20 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 80 parts by weight of the hydrogenated copolymer obtained in Production Example 1 was used as a resin for the layer (B).

  Further, a polyethylene resin having a bond of about 9.5% by weight of methylmethacrylate (produced by Arkema Co., Ltd., variety Rotril 9MA02, melting point 99 ° C. was used as the resin for the layer (C).

  Three-layer coextrusion molding was performed using the above three types of resins. That is, the resin for each layer is supplied to three screw-type extruders, co-extruded from a three-layer T die so as to be (A) / (B) / (C), cooled and taken out without stretching. It was. At this time, the barrel temperature of each extruder was 180 to 220 ° C., the three-layer T die temperature was 220 ° C., and the cooling roll temperature was 60 ° C.

  The total thickness of the obtained three-layer dicing substrate film was 80 μm, the layer (A) was 8 μm, the layer (B) was 64 μm, the layer (C) was 8 μm, and the styrene ratio of the entire film was 61%. .

Example 7 (Multilayer film)
A resin obtained by dry blending 100 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 30 parts by weight of a soft acrylic resin (manufactured by Kuraray Co., Ltd., SA-D, Tg 60 to 65 ° C.) is formed into a layer (D ) Resin.

  A resin obtained by dry blending 30 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 70 parts by weight of the hydrogenated copolymer obtained in Production Example 1 was used as a resin for the layer (E).

  The hydrogenated copolymer obtained in Production Example 2 was used as the layer (F) resin.

  Three-layer coextrusion molding was performed using the above three types of resins. That is, the resin for each layer is supplied to three screw-type extruders, co-extruded from a three-layer T die so as to be (D) / (E) / (F), cooled and taken out without stretching. It was. At this time, the barrel temperature of each extruder was 180 to 220 ° C., the three-layer T die temperature was 220 ° C., and the cooling roll temperature was 60 ° C.

  The total thickness of the obtained three-layer dicing substrate film was 80 μm, the layer (A) was 8 μm, the layer (B) was 64 μm, the layer (C) was 8 μm, and the styrene ratio of the entire film was 62%. .

Comparative Example 1
10 parts by weight of the hydrogenated copolymer obtained in Production Example 2 and 90 parts by weight of the hydrogenated copolymer obtained in Production Example 1 are dry blended and supplied to a screw type extruder having a barrel temperature of 180 to 220 ° C. Then, it was extruded from a single layer T die at 220 ° C., cooled and solidified while passing through a 60 ° C. cooling roll, and wound up in an unstretched state to produce a substrate film for dicing.

  The thickness of the obtained film was 80 μm, and the styrene ratio of the whole film was 66%.

Comparative Example 2
Dicing is performed under the same conditions as in Example 4 except that MS binary resin (MMA / styrene) (manufactured by Denki Kagaku Kogyo Co., Ltd., type TX600S, Tg99 ° C.) is used instead of the hydrogenated copolymer obtained in Production Example 2. A substrate film for use was obtained.

  The thickness of the obtained film was 80 μm, and the styrene ratio of the whole film was 58%.

Test example 1
The transparency and warm air restoration property (restoration rate) of the films obtained in Examples and Comparative Examples were measured as follows.
<Transparency (Haze,%)>
It measured according to JIS-Z-8741. 15% or less was rated as “◯”, and 15% was scored as “x”. The reason why the upper limit of the allowable Haze is 15% is that the transparency is required to facilitate visual inspection of the semiconductor wafer chip.
<Hot air resilience>
A film cut in the vertical direction (MD) and the horizontal direction (TD) with a width of 10 mm is taken as a sample. The sample was set in a tensile tester (AGS100A) manufactured by Shimadzu Corporation with a distance between chucks of 40 mm (same meaning as the distance between marked lines of the sample of 40 mm), and stretched 40% at a tensile speed of 200 mm / min. After being held for 1 minute by the extension, the extended state was released. The released sample was blown with warm air of 60 ° C. for 10 seconds, returned to room temperature, measured for length, and the restoration rate (%) in the vertical and horizontal directions for 40% elongation was obtained.

  If the restoration rate is 95% or more in the vertical and horizontal directions, it is possible to quickly and easily store and collect the dicing sheet in the rack even for small wafers of 1 × 1 mm cut size. If it was less than 95%, it was deemed “x”.

  As shown in Table 2, it was found that the films of Examples 1 to 7 had high transparency and excellent warm air restoring properties.

Claims (4)

  (I) 100-20% by weight of a styrene elastomer resin (SE resin A) having a glass transition temperature of 40-60 ° C and a styrene ratio of 70-90% by weight, and (ii) a glass transition temperature of 30 ° C or less. A substrate film for dicing comprising a styrene elastomer resin composition (SE resin composition) comprising 0 to 80 wt% of a styrene elastomer resin (SE resin B) having a styrene ratio of 7 to 80 wt%.   The substrate film for dicing according to claim 1, wherein the styrene ratio of the entire styrene elastomer resin composition is 40 to 90% by weight.   The substrate film for dicing according to claim 1 or 2, comprising a multilayer structure having at least one layer containing the styrenic elastomer resin composition.   The dicing substrate film according to claim 1, further comprising an adhesive layer on the dicing substrate film.