JP5977954B2 - Semiconductor wafer processing sheet - Google Patents

Description

  The present invention relates to a semiconductor wafer processing sheet, and more particularly to a sheet used for fixing a semiconductor wafer when processing such as dicing is performed on the semiconductor wafer. Moreover, the other aspect of this invention is related with the dicing die-bonding sheet | seat which has a function of a dicing sheet and a film adhesive.

  Various pressure-sensitive adhesive sheets and film adhesives are used in a series of steps of dicing a semiconductor wafer and die-bonding the obtained chips.

  For example, the pressure-sensitive adhesive sheet used in the dicing step is composed of a base material and a pressure-sensitive adhesive layer, and is used for fixing the semiconductor wafer when dicing the semiconductor wafer and holding the chip after dicing. Further, a chip diced on the pressure-sensitive adhesive sheet may be picked up directly from the pressure-sensitive adhesive sheet, or may be picked up after the chip is transferred to a pressure-sensitive adhesive sheet for semiconductor pickup.

  After the dicing process is completed, chip die bonding is performed. At this time, a liquid adhesive may be used, but in recent years, film adhesives are frequently used. The film adhesive is adhered to one surface of a semiconductor wafer, cut together with the wafer in a dicing process, and then picked up as a chip with an adhesive layer, and the chip is bonded to a predetermined site via the adhesive layer. . Such a film-like adhesive is obtained by forming a semi-solidified layer of an adhesive such as epoxy or polyimide on a base film or a pressure-sensitive adhesive sheet.

  Furthermore, a dicing / die-bonding sheet that simultaneously has a wafer fixing function during dicing and a die bonding function during die-bonding has also been proposed. The dicing / die-bonding sheet includes an adhesive layer and a base material. The adhesive layer holds a semiconductor wafer or chip in the dicing process, and functions as an adhesive for fixing the chip during die bonding. The adhesive layer is cut together with the wafer at the time of dicing, and an adhesive layer having the same shape as the cut chip is formed. When the chip is picked up after the dicing is completed, the adhesive layer is peeled off together with the chip. The chip with the adhesive layer is placed on the substrate, heated, etc., and the chip and the substrate are bonded via the adhesive layer. Such a dicing / die-bonding sheet is formed by forming an adhesive layer having a wafer fixing function and a die bonding function on a base material.

  In addition, in order to form a protective film on the surface of the chip, a semiconductor wafer is attached to the curable resin layer, the resin layer is cured, and then the semiconductor wafer and the resin layer are diced, and the cured resin layer (protective film) A process for manufacturing a chip having) has also been proposed. Such a sheet for forming a protective film has an adhesive resin layer serving as a protective film on a peelable substrate.

  In wafer processing using these semiconductor wafer processing sheets, expansion is performed after dicing, and the chip interval is separated to facilitate chip pickup. For this reason, the wafer processing sheet may be required to be flexible enough to expand. Therefore, a polyvinyl chloride film containing a plasticizer is often used as a base material for the semiconductor wafer processing sheet (Patent Documents 1 and 2).

  As a plasticizer blended with polyvinyl chloride, an alkyl ester of an aromatic dicarboxylic acid, typically dioctyl phthalate (DOP) is used. Soft polyvinyl chloride (PVC) films containing plasticizers such as DOP are widely used as base materials for various pressure-sensitive adhesive sheets because of their excellent mechanical properties (PVC) and the flexibility of plasticizers. Yes.

  However, DOP is a candidate for regulation under the RoHS (Dangerous Substances Restriction) Directive in Europe, and in REACH (European Parliament and European Council Regulations for the Protection of Human Health and the Environment in the European Union) It is listed as an approved substance (substance of high concern). For this reason, there is a very high possibility that the use of DOP will be restricted in the future, and search for alternative substances is being conducted.

  As an alternative to DOP, attention has been focused on adipic acid ester, but sufficient characteristics are not obtained in terms of its chemical structure. For example, when adipic acid ester is used as the base material of the pressure-sensitive adhesive sheet for electronic member processing, there is no problem immediately after the pressure-sensitive adhesive is formed on the base material, but the adhesive component is not attached to the adherend after storage for a certain period of time. There was a case of transfer. The electronic member to which the adhesive has been transferred may cause various problems after the subsequent process or mounting. Moreover, even if it is a compound which phthalic acid is hard to generate | occur | produce as a derivative, such as trimellitic acid ester, since it has an aromatic ring, there exists a concern containing phthalic acid as an impurity.

JP 2001-207140 A JP 2010-260893 A

  The present invention has been made in view of the prior art as described above, and for semiconductor wafer processing that exhibits sufficient expandability and has little change in adhesive properties over time even though the substrate does not contain DOP. The purpose is to provide a seat.

The gist of the present invention for solving the above problems is as follows.
(1) A semiconductor wafer processing sheet having an adhesive resin layer on at least one surface of a vinyl chloride base material containing an alicyclic ester compound as a plasticizer.

(2) The semiconductor wafer processing sheet according to (1), wherein the alicyclic ester compound is a diester of cyclohexanedicarboxylic acid and an alcohol having 6 to 12 carbon atoms.

(3) The semiconductor wafer processing sheet according to (2), wherein the cyclohexanedicarboxylic acid is 1,2-cyclohexanedicarboxylic acid and the alcohol is isononyl alcohol.

(4) The semiconductor wafer processing according to any one of (1) to (3), wherein the content of the alicyclic ester compound in the vinyl chloride substrate is 5 to 100 parts by mass with respect to 100 parts by mass of vinyl chloride. Sheet.

(5) The semiconductor wafer processing sheet according to any one of (1) to (4), wherein the adhesive resin layer has pressure-sensitive adhesiveness.

(6) The semiconductor wafer processing sheet according to (5), wherein the adhesive resin layer is made of an energy ray-curable pressure-sensitive adhesive.

(7) The semiconductor wafer processing sheet according to (5) or (6), wherein the adhesive resin layer is made of an acrylic pressure-sensitive adhesive.

(8) The semiconductor wafer processing sheet according to (7), wherein the (meth) acrylic acid ester copolymer contained in the acrylic pressure-sensitive adhesive has a glass transition temperature of −50 to 30 ° C.

(9) The semiconductor wafer processing sheet according to any one of (1) to (8), which is used for holding the semiconductor wafer and the chips after dicing when dicing the semiconductor wafer.

(10) The semiconductor wafer processing sheet according to any one of (1) to (9), wherein the adhesive resin layer contains an epoxy adhesive or a polyimide adhesive.

(11) The semiconductor wafer processing sheet according to (9) or (10) for transferring the adhesive resin layer to the semiconductor wafer and the chip after dicing.

  In the present invention, a vinyl chloride base material containing an alicyclic ester compound as a plasticizer is used as a base material for a semiconductor wafer processing sheet, and the semiconductor exhibits sufficient expandability and has little change in adhesive properties over time. A wafer processing sheet is obtained. That is, the performance equivalent to or higher than that of the DOP-use product could be achieved without using the DOP. For this reason, it is expected to be developed as an alternative to the DOP-use product that will be regulated in the future.

  Hereinafter, the semiconductor wafer processing sheet according to the present invention will be described more specifically.

  The sheet for processing a semiconductor wafer according to the present invention has a base material and an adhesive resin layer formed on at least one surface thereof.

(Base material)
The base material is made of a vinyl chloride resin containing an alicyclic ester compound as a plasticizer.

The vinyl chloride resin used in the present invention refers to all polymers having a repeating unit represented by —CH ₂ —CHCl—, such as a vinyl chloride homopolymer and an ethylene-vinyl chloride copolymer. A copolymer of a monomer and a polymerizable monomer, and a homopolymer or modified copolymer such as a chlorinated vinyl chloride copolymer, or a chlorinated polyethylene similar in structure to a vinyl chloride resin such as chlorinated polyethylene. Include. Further, these vinyl chloride resins preferably have a number average degree of polymerization of 300 to 3000, and more preferably 1000 to 2500. These vinyl chloride resins can be used alone or in combination of two or more to form a vinyl chloride resin component constituting the substrate.

Alicyclic ester used as the plasticizer is an ester of an alicyclic dicarboxylic acid and an alcohol. As alicyclic esters, cyclobutanedicarboxylic acid esters, cyclopentanecarboxylic acid, cyclohexanedicarboxylic acid and other alicyclic carboxylic acids, methanol, ethanol, propanol, n-butanol, n-pentanol, n-hexanol, n Examples include esters with alcohols such as -heptanol, n-octanol, 2-ethylhexanol, n-nonanol, isononanol, n-decanol, n-dodecanol, n-tetradecanol.

  The alicyclic dicarboxylic acid is preferably cyclohexanedicarboxylic acid from the viewpoint of steric stability, and the substitution position of the carboxyl group is not particularly limited, but is preferably 1,2-cyclohexanedicarboxylic acid. The alcohol is preferably an alcohol having 6 to 12 carbon atoms, more preferably an alcohol having 8 to 10 carbon atoms, and particularly preferably isononanol. Therefore, the plasticizer particularly preferably used in the present invention is 1,2-cyclohexanedicarboxylic acid diisononyl ester.

  The use of alicyclic esters inevitably eliminates phthalic acid diesters, which are aromatic esters, and drastically reduces the possibility of containing phthalic acid as an impurity. It is possible to plasticize a base material mainly composed of a resin. Further, when the semiconductor wafer processing sheet of the present invention is an adhesive sheet in which a removable adhesive layer is provided on a base material, the sheet is manufactured during the storage after the manufacture of the sheet as described later. The plasticizer inside the material may move into the pressure-sensitive adhesive layer and be taken into the pressure-sensitive adhesive layer. In such a case, the principle is not clear, but depending on the choice of esters, when used as a plasticizer for the substrate, the components of the adhesive layer may be different when peeling the semiconductor wafer processing sheet from the semiconductor wafer. A defect (glue residue) may remain in the semiconductor. The occurrence of such an adhesive residue phenomenon tends to become more prominent with time after the production of the semiconductor wafer processing sheet. When the alicyclic ester is used, the generation of such a residue on the semiconductor wafer can be suppressed.

  The content of the alicyclic ester compound in the substrate is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass, particularly preferably 20 to 100 parts by mass of the vinyl chloride resin constituting the substrate. 40 parts by mass. If the content of the alicyclic ester compound in the substrate is too small, the substrate is not flexible, and the expandability of the semiconductor wafer processing sheet becomes insufficient. If the content of the alicyclic ester compound in the base material is excessive, the base material becomes excessively soft and the handling property is lowered, or the plasticizer of the base material moves to the adhesive resin layer, and the adhesive resin layer The performance may change over time. In addition, when the content of the alicyclic ester in the base material is in such a range, in the pressure-sensitive adhesive sheet provided with a re-peelable pressure-sensitive adhesive layer on the base material as described later, the sheet is stored after manufacture. During this, a phenomenon in which the plasticizer inside the base material moves to the inside of the pressure-sensitive adhesive layer easily occurs. Even in that case, the problem of adhesive residue of the pressure-sensitive adhesive can be prevented by using the alicyclic ester as a plasticizer for the base material.

  The base material may further contain a filler for improving the strength. Furthermore, in order to impart chemical stability, a barium / zinc stabilizer, a calcium / zinc stabilizer, or the like may be blended. Such a stabilizer may be contained at a ratio of about 1.5 to 3.5 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. In addition to these, additives such as a colorant, an antistatic agent, an antioxidant, an organic lubricant, an ultraviolet absorber, and a light stabilizer may be contained. These fillers, stabilizers, additives and the like may be contained at a ratio of about 1.0 to 8.0 parts by mass with respect to 100 parts by mass of the vinyl chloride resin. Moreover, you may contain plasticizers other than the said alicyclic ester compound in the range which does not impair the objective of this invention.

  The thickness of the substrate is not particularly limited and varies depending on the use of the semiconductor wafer processing sheet, but is generally about 10 to 300 μm, preferably about 40 to 120 μm. If the base material is too thin, the sheet will be used for fixing to the workpiece in the dicing process, and if the base material is cut by the dicing blade, the thickness of that part will become extremely thin, and during expansion There is a risk of tearing. If it is too thick, the tensile force may increase and the expansibility may decrease. Furthermore, in order to improve the adhesiveness with the adhesive resin layer, the surface of the substrate that contacts the adhesive resin layer may be subjected to corona treatment or other layers such as a primer. Furthermore, when peeling the adhesive resin layer from the substrate and transferring the adhesive resin layer to the chip, etc., it is peeled off from the substrate surface to facilitate peeling between the adhesive resin layer and the substrate. Processing may be performed. In this case, the surface tension of the substrate is preferably 40 mN / m or less, more preferably 37 mN / m or less, and particularly preferably 35 mN / m or less. As the release agent used for the release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, and the like are used. In particular, alkyd, silicone, and fluorine release agents are heat resistant. This is preferable.

  In order to release the surface of the substrate using the above release agent, the release agent can be applied as it is without solvent, or after solvent dilution or emulsification, using a gravure coater, Mayer bar coater, air knife coater, roll coater, etc. Then, the laminate may be formed by room temperature or heating or electron beam curing, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like.

  In addition, vinyl chloride resins are generally inferior in heat resistance, and the above-described peeling treatment means may not be taken. In such a case, it is possible to use an energy ray curable release agent as the release agent, apply the release agent to the vinyl chloride resin film for the substrate, and cure by irradiation with energy rays. .

  Although the manufacturing method of a base material is not specifically limited, The said vinyl chloride resin, the alicyclic ester compound as a plasticizer, a stabilizer, and other additives are mixed, and the obtained mixture is formed into a film.

  For mixing the components, a single-screw extruder, a twin-screw extruder, a Banbury mixer, various kneaders, a brabender, a calender roll and the like are generally used by a mechanical melt kneading method. At this time, there is no restriction on the order of adding each component. The temperature for melt kneading can be suitably selected from 140 ° C to 220 ° C.

  The obtained mixture is processed into a sheet to obtain a substrate. The sheet processing may be performed by a general molding processing method such as extrusion molding, calendar molding, and inflation molding.

  The film forming method may be a method in which the mixture exemplified above is made into a solution or a molten state, and coating is performed by a coating means such as a knife coater.

(Adhesive resin layer)
The adhesive resin layer in the semiconductor wafer processing sheet is appropriately selected from resins having various functions depending on the use of the sheet.

(Pressure-sensitive adhesive resin layer)
Among them, the semiconductor wafer processing sheet is particularly preferably a pressure-sensitive adhesive sheet composed of a pressure-sensitive adhesive layer (adhesive layer) in which the adhesive resin layer has removability, and the semiconductor wafer processing sheet is used as a dicing sheet. It is particularly preferred. The semiconductor wafer processing sheet is composed of a soft vinyl chloride resin containing a plasticizer, so it has excellent expandability. In particular, the chip spacing is easy to expand isotropically, so chip alignment after expansion Excellent in properties. In addition, it is difficult for cutting pieces to be generated due to the dicing blade sliding at the contact portion with the substrate. In addition, the phenomenon that the chip is chipped or broken due to an impact at the time of cutting hardly occurs. The use of the adhesive sheet is not limited to the dicing sheet. For example, after expanding the chip separated from the other sheet, the expanded sheet such as a sheet for picking up the chip (pickup) can be used. The accompanying application is preferable from the same viewpoint.

  In a semiconductor wafer processing sheet provided with a pressure-sensitive adhesive layer on a base material made of a vinyl chloride resin containing a plasticizer, the plasticizer present inside the base material may migrate to the inside of the pressure-sensitive adhesive layer during storage. is there. This is due to a diffusion phenomenon caused by the concentration gradient of the plasticizer inside the base material and inside the pressure-sensitive adhesive layer, and is more likely to occur as the concentration of the plasticizer in the base material is higher. Even when the plasticizer moves to the pressure-sensitive adhesive layer as described above, it is possible to suppress the adhesive residue by using the alicyclic ester as the plasticizer for the substrate as described above. The dicing sheet is used to hold a semiconductor wafer and chips generated by dicing when the semiconductor wafer is diced into chips. Therefore, it is required to have an appropriate re-peelability that can peel the chip after dicing. Such a pressure-sensitive adhesive layer can be formed by various conventionally known pressure-sensitive adhesives (pressure-sensitive adhesives). The pressure-sensitive adhesive is not limited at all. For example, a rubber-based, acrylic-based, silicone-based, polyvinyl ether, or other pressure-sensitive adhesive is used. Among these, an acrylic pressure-sensitive adhesive that can easily control the adhesive force is particularly preferable.

  The acrylic pressure-sensitive adhesive mainly comprises a (meth) acrylic acid ester copolymer. Examples of (meth) acrylic acid ester copolymers include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, -2-ethylhexyl acrylate, decyl acrylate, dodecyl acrylate, lauryl acrylate, and myristyl acrylate. One or more of (meth) acrylate esters in which only hydrocarbons are added to ester structures such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, benzyl acrylate, cyclohexyl acrylate, and isobornyl acrylate Monomer and optionally, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 3-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, Metacri Hydroxyl group-containing (meth) acrylic acid alkyl esters such as acid-2-hydroxyethyl, methacrylate-2-hydroxypropyl, methacrylate-3-hydroxypropyl, methacrylate-3-hydroxybutyl, methacrylate-4-hydroxybutyl; Carboxyl group-containing compounds such as acrylic acid, methacrylic acid, maleic acid and fumaric acid; Vinyl esters such as vinyl acetate and vinyl propionate; Cyano group-containing compounds such as acrylonitrile and methacrylonitrile; Amide group-containing compounds such as acrylamide; Styrene And a copolymer of one or more monomers selected from polymerizable monomers such as aromatic compounds such as vinylpyridine. In addition, although it is not a narrowly-defined copolymer when the polymerizable monomer is one kind, it is generically called a copolymer including such a case.

  The content ratio of the unit derived from the (meth) acrylic acid ester in which only the hydrocarbon is added to the ester structure in the (meth) acrylic acid ester copolymer is preferably 10 to 98% by mass, and more preferably 20 to 95% by mass. 50 to 93% by mass is more preferable. The weight average molecular weight of the (meth) acrylic acid ester copolymer is preferably 100,000 to 2,500,000, more preferably 200,000 to 1,500,000, and particularly preferably 300,000 to 1,000,000. In the present specification, the weight average molecular weight is a value in terms of standard polystyrene measured by gel permeation chromatography.

  These pressure-sensitive adhesives can be used alone or in combination of two or more. Of these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used. In particular, an acrylic pressure-sensitive adhesive obtained by crosslinking an acrylic copolymer with one or more of a crosslinking agent such as a polyisocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, or a chelating crosslinking agent is preferable. .

The epoxy based crosslinking agent, (1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N, N ', N'Tetoraguri sheet Jill -m- xylylene amine, N, N, N ', N'- Tetoraguri sheet Jill aminophenyl methane, triglycidyl isocyanate, m-N, N-diglycidyl-aminophenyl glycidyl ether, N, N-diglycidyl toluidine, N, N-diglycidyl aniline, pentaerythritol polyglycidyl ether 1,6-hexanediol diglycidyl ether and the like.

  Polyisocyanate-based crosslinking agents include tolylene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated tolylene diisocyanate, diphenylmethane Examples thereof include diisocyanates and hydrogenated products thereof, polymethylene polyphenyl polyisocyanates, naphthylene-1,5-diisocyanates, polyisocyanate prepolymers, and polymethylolpropane-modified TDI.

  A crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type. As for the usage-amount of a crosslinking agent, 0.01-20 mass parts is preferable with respect to 100 mass parts of acrylic copolymers.

  Furthermore, when the semiconductor wafer processing sheet is used as a dicing sheet, the pressure-sensitive adhesive layer may be a pressure-sensitive adhesive whose adhesive force can be controlled by energy ray curing, heat foaming, water swelling, or the like. The energy ray-curable pressure-sensitive adhesive layer can be formed of various energy ray-curable pressure-sensitive adhesives that are cured by irradiation with energy rays such as gamma rays, electron beams, ultraviolet rays, and visible light that are conventionally known. It is preferable to use an agent.

  Examples of the energy ray curable pressure sensitive adhesive include a pressure sensitive adhesive obtained by mixing a polyfunctional energy ray curable resin with an acrylic pressure sensitive adhesive. Examples of the polyfunctional energy ray curable resin include low molecular weight compounds having a plurality of energy ray polymerizable functional groups, urethane acrylate oligomers, and the like. An adhesive containing an acrylic copolymer having an energy ray polymerizable functional group in the side chain can also be used. Such an energy ray polymerizable functional group is preferably a (meth) acryloyl group.

  In this invention, -50 degreeC-30 degreeC is preferable and, as for the glass transition temperature (Tg) of an adhesive layer, it is preferable that it is -25 degreeC-30 degreeC. Moreover, when there is much content of alicyclic ester in a base material, it is preferable that the glass transition temperature (Tg) of an adhesive layer is 0-30 degreeC, and it is more preferable that it is 5-25 degreeC. Here, the Tg of the pressure-sensitive adhesive layer is the temperature at which the loss tangent (tan δ) shows the maximum value in the region of −50 to 50 ° C. in the dynamic viscoelasticity measurement at a frequency of 11 Hz of the sample on which the pressure-sensitive adhesive layer is laminated. Point to. In addition, when an adhesive layer is an energy ray hardening-type adhesive, the glass transition temperature before hardening an adhesive layer by energy ray irradiation is pointed out. When the pressure-sensitive adhesive layer is composed of the above-mentioned acrylic pressure-sensitive adhesive, the glass transition temperature of the pressure-sensitive adhesive layer regulates the type and polymerization ratio of the monomers constituting the above-mentioned acrylic pressure-sensitive adhesive, and is added in some cases. It can be controlled by estimating the influence of the ultraviolet curable compound and the crosslinking agent.

  The preferable range of the glass transition temperature of the pressure-sensitive adhesive layer when the content of the alicyclic ester in the substrate is large is higher than the range generally preferable for the pressure-sensitive adhesive. The reason why such a range is preferable is as follows. As described above, in the pressure-sensitive adhesive sheet according to one embodiment of the present invention, the plasticizer inside the substrate may move to the pressure-sensitive adhesive layer. And the adhesive layer encloses a plasticizer by transfer, and there exists a tendency for an adhesive layer to soften. Even in this case, if the glass transition temperature is in the above range, the cohesive force of the pressure-sensitive adhesive layer is not excessively reduced, and the adhesive residue preventing effect is hardly impaired.

  Such a dicing sheet has been widely used for semiconductor processing, and has an adhesive strength that fixes the wafer during dicing and prevents chips generated by dicing from scattering. After the dicing process is completed, the chip is picked up. At this time, a chip is picked up from the dicing sheet using a push-up pin, a suction collet, or the like. Further, when the pressure-sensitive adhesive layer has energy ray curability, the chip can be more easily picked up by irradiating the pressure-sensitive adhesive layer with energy rays to reduce the adhesive force. Further, when picking up the chips, it is preferable to expand the dicing sheet in a state where the chips are fixed to the dicing sheet in order to separate the intervals between the chips. By expanding, the distance between the chips is increased, the chips can be easily recognized, the damage due to the contact between the chips is reduced, and the yield is improved.

(Film adhesive)
The adhesive resin layer may be a film adhesive. Such film adhesives are frequently used in the die bonding process of chips in recent years. Such a film-like adhesive is preferably an epoxy-based adhesive or a polyimide-based adhesive formed into a film and semi-cured, and is formed so as to be peelable on the substrate or the above-mentioned pressure-sensitive adhesive sheet. A semiconductor wafer processing sheet is obtained.

  The film adhesive layer is attached to the semiconductor wafer. The semiconductor wafer and the film-like adhesive layer are diced to a chip size to obtain a chip with an adhesive layer, which is picked up from the base material or the pressure-sensitive adhesive sheet, and passed through the adhesive layer to a predetermined position. Affix the chip to. In addition, when picking up the chip | tip with an adhesive layer, it is preferable to expand like the above.

  Further, the semiconductor wafer processing sheet of the present invention may be a dicing / die-bonding sheet having both a wafer fixing function during dicing and a die bonding function during die bonding. In this case, by making the adhesive resin layer sticky or having a property that can be softened by heating and attached to the adherend, the semiconductor wafer or chip can be held in the dicing process. And it functions as an adhesive for fixing the chip during die bonding. The adhesive layer is cut together with the wafer at the time of dicing, and an adhesive layer having the same shape as the cut chip is formed. When the chip is picked up after the dicing is completed, the adhesive layer is peeled off from the substrate together with the chip. A chip with an adhesive layer is placed on the substrate, heated, etc., and the chip and an adherend such as a substrate or another chip are bonded via the adhesive layer. Such a dicing / die-bonding sheet is formed by forming an adhesive layer having a wafer fixing function and a die bonding function on a base material. Such an adhesive having both a wafer fixing function and a die bonding function includes, for example, the above-mentioned acrylic pressure-sensitive adhesive and an epoxy adhesive, and, if necessary, an energy beam curable compound and a curing aid. . In order to facilitate the transfer of the adhesive resin layer to the chip, it is preferable that the base material in the dicing / die-bonding sheet is subjected to a peeling treatment. In addition, when picking up a chip with an adhesive layer, it is preferable to perform expansion in the same manner as described above.

(Protective film forming sheet)
Further, the semiconductor wafer processing sheet may be a protective film forming sheet for forming a protective film on the back surface of the chip. In this case, a semiconductor wafer is attached to the adhesive resin layer, the adhesive resin layer is cured, and then the semiconductor wafer and the resin layer are diced to obtain a chip having a cured resin layer (protective film). Such a sheet for forming a protective film has an adhesive resin layer serving as a protective film on a peelable substrate. The adhesive resin layer serving as a protective film contains the above-mentioned acrylic pressure-sensitive adhesive, an epoxy adhesive and a curing aid, and may contain a filler or the like as necessary.

  The thickness of the adhesive resin layer in the semiconductor wafer processing sheet of the present invention varies depending on its use.When used as a dicing sheet, it is about 30 to 200 μm, and when used as a dicing / die-bonding sheet, It is about 50-300 micrometers.

  As described above, the representative composition and application of the adhesive resin layer of the semiconductor wafer processing sheet of the present invention have been outlined, but the adhesive resin layer in the semiconductor wafer processing sheet of the present invention is limited to the above. There is no particular limitation on its use.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. The measurement and evaluation methods employed in the present invention are as follows.

<Adhesion measurement>
As conditions simulating long-term aging, the semiconductor wafer processing sheets prepared in Examples and Comparative Examples were put under accelerated conditions (40 ° C. for 7 days or 40 ° C. for 14 days). After that, the sheet was stored for 24 hours in an environment of 23 ° C. and 50% relative humidity, and then a silicon wafer (diameter 6 inches, thickness 650 μm, chemical mechanical) was prepared by cutting the sheet 25 mm wide and 250 mm long. Residue removal treatment with alkali and then acid after polishing, Warpage standard: Particles with an edge distance of 100 μm or less when placed on a horizontal surface and a diameter of 0.2 μm or more on a sample application surface: 30 Abundant, Al, Cr, Cu, Fe, Ni, Zn, Na element abundance: less than 5 × 10 ¹⁰ atoms / cm ² ) and stored in an environment of 23 ° C. and 50% relative humidity for 30 minutes after irradiation with ultraviolet (UV irradiation apparatus: Adwill (registered trade mark) RAD-2000m / 12 (Lintec ^{Corporation), 230mW / cm 2, 190mJ} / cm 2) to cure the to the adhesive layer, 3 ° C. and 50% relative humidity the release rate of 300 mm / min after storage for 10 minutes under the environment was measured force when peeled sheet at a peeling angle of 180 °. Moreover, the adhesive force was similarly measured about the sheet | seat which is not irradiated with an ultraviolet-ray.

<Evaluation of adhesive residue>
In the adhesive force measurement, the presence or absence of adhesive residue on the surface of the silicon wafer where the sheet was peeled was confirmed. The case where the adhesive residue was not confirmed was designated as “A”, and the case where the adhesive residue was confirmed was designated as “F”.

<Expandability>
The semiconductor wafer processing sheet of Example 1 and Reference Example 1 was affixed to a 6-inch silicon wafer (thickness 350 μm), and a 8 mm × 8 mm chip using a dicing blade 27HECC with a dicer (Disco, DFD651). It was separated into pieces. Subsequently, expansion was performed with a withdrawal amount of 10 mm, and the chip intervals in the horizontal direction (X direction) and the vertical direction (Y direction) were confirmed with a digital microscope.

<Measurement of glass transition temperature of adhesive layer>
Using a roll knife coater, a polyethylene terephthalate (PET) film (thickness 38 μm) obtained by subjecting the energy ray hard adhesive composition of the example diluted with a solvent to a silicone release treatment so that the coating thickness after drying is 10 μm. ), And dried at 100 ° C. for 1 minute, and a silicone film with a different peeling force is bonded to the exposed surface of the adhesive layer, and the adhesive is sandwiched between two PET films. A layer was obtained. Next, after storing for 7 days in an environment of 23 ° C. and 50% RH, only the pressure-sensitive adhesive layer excluding the PET film was laminated until the thickness became 1 mm. The pressure-sensitive adhesive layer laminated to a thickness of 1 mm was punched into a cylindrical shape having a diameter of 8 mm, and further laminated to a thickness of 3 mm to obtain a measurement sample. The tan δ (loss tangent) of this sample measured at a frequency of −50 ° C. to 110 ° C. at a frequency of 11 Hz was measured using a viscoelasticity measuring device (RENATRIC, DYNAMIC ANALYZER RADII). The temperature at which the maximum value of tan δ was in the range of −50 ° C. to 50 ° C. was defined as the glass transition temperature.

Example 1
(Base material)
100 parts by weight of a polyvinyl chloride resin (average degree of polymerization 1100), 30 parts by weight of 1,2-cyclohexanedicarboxylic acid diisononyl ester (product name: Hexamoll-DINCH) as a plasticizer, barium / zinc stabilizer 2 The mixture composed of 8 parts by weight was kneaded at 180 ° C. using a Banbury mixer. This mixture was rolled with a calendar roll to obtain a vinyl chloride resin base material having a thickness of 80 μm.

(Adhesive layer)
Acrylate ester copolymer (2-ethylhexyl acrylate: 20 parts by mass, vinyl acetate: 78 parts by mass, acrylic acid: 1 part by mass, 2-hydroxyethyl methacrylate: copolymer obtained from 1 part by mass, weight average molecular weight: 100,000 parts), 100 parts by mass of organic polyisocyanate compound (manufactured by Toyochem Co., Ltd., trade name: BHS8515) as a curing agent, 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals Co., Ltd.) as a photopolymerization initiator Manufactured and trade name: Irgacure 184) 2.6 parts by mass, and 85.7 parts by mass of a mixture of 1: 1 ratio of bifunctional urethane acrylate and hexafunctional urethane acrylate as an energy ray-curable compound (solid mass ratio) To obtain an energy ray-curable pressure-sensitive adhesive composition. The glass transition temperature of the pressure-sensitive adhesive layer obtained by this composition is 17 ° C.

(Creation of semiconductor wafer processing sheet)
The energy ray-curable pressure-sensitive adhesive composition is applied to a release material (SP-PET 381031, manufactured by Lintec Corporation) so as to be diluted with a solvent to a coating amount of 10 g / m ^2, and then dried, and the pressure-sensitive adhesive layer surface And the substrate were laminated so as to face each other, and a semiconductor wafer processing sheet was produced. In addition, the corona treatment was performed to the base material beforehand and the adhesive layer was laminated | stacked on the corona treatment surface.

  Table 1 shows <adhesive residue evaluation> using the obtained semiconductor wafer processing sheet, Table 2 shows the measurement results of <Adhesive strength measurement>, and Table 3 shows the results of <Expandability>.

(Comparative Example 1)
The same procedure as in Example 1 was conducted except that di (2-ethylhexyl) adipate was used as a plasticizer to be blended with the substrate. The results are shown in Tables 1 and 2.

(Comparative Example 2)
The same procedure as in Example 1 was conducted except that di (2-ethylhexyl) terephthalate was used as a plasticizer to be blended with the base material. The results are shown in Tables 1 and 2.

(Comparative Example 3)
The same procedure as in Example 1 was performed except that di (2-ethylhexyl) phthalate was used as a plasticizer to be blended with the base material. The results are shown in Tables 1 and 2.

(Comparative Example 4)
The same procedure as in Example 1 was performed except that an ethylene / methacrylic acid copolymer film having a thickness of 80 μm was used as the substrate. The results of <Expand aptitude> are shown in Table 3. When the semiconductor processing sheet of Comparative Example 4 was used, the expansion in the X direction and the Y direction was not uniform, and the expandability was inferior.

Claims (8)

A semiconductor wafer processing sheet having an adhesive resin layer on at least one surface of a vinyl chloride base material containing an alicyclic ester compound as a plasticizer ,
The alicyclic ester compound is a diester of 1,2-cyclohexanedicarboxylic acid and isononyl alcohol;
The semiconductor wafer processing sheet, wherein the adhesive resin layer contains an acrylic pressure-sensitive adhesive . 2. The semiconductor wafer processing sheet according to claim 1, wherein the content of the alicyclic ester compound in the vinyl chloride substrate is 5 to 100 parts by mass with respect to 100 parts by mass of vinyl chloride. Adhesive resin layer, a semiconductor wafer processing sheet according to claim 1 or 2 having pressure sensitive adhesive properties. The semiconductor wafer processing sheet according to any one of claims 1 to 3 , wherein the adhesive resin layer is made of an energy ray-curable pressure-sensitive adhesive. The glass transition temperature of the (meth) acrylic acid ester copolymer contained in the acrylic pressure-sensitive adhesive is -50 to 30 ° C. The semiconductor wafer processing sheet according to any one of claims 1 to 4 . When performing dicing of the semiconductor wafer, the semiconductor wafer processing sheet according to any one of claims 1 to 5, which is used to hold the semiconductor wafer and the dicing after a chip. The semiconductor wafer processing sheet according to any one of claims 1 to 6 , wherein the adhesive resin layer contains an epoxy adhesive or a polyimide adhesive. The semiconductor wafer processing sheet according to claim 6 or 7 , for transferring the adhesive resin layer to the semiconductor wafer and the chip after dicing.