JP2006342330A - Pressure-sensitive adhesive sheet for dicing and method for dicing using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive sheet for dicing slightly forming filamentous wastes during dicing without deteriorating product quality or causing disadvantages to cost and to provide a method for dicing using the pressure-sensitive adhesive sheet for dicing. <P>SOLUTION: The pressure-sensitive adhesive sheet 10 for dicing has a pressure-sensitive adhesive layer 12 on at least one surface of a substrate 11. Furthermore, the substrate 11 is provided with a multilayer structure having a layer 11a containing an ethylenic resin having ≤95°C melting point. The pressure-sensitive adhesive sheet for dicing is characterized in that the thickness of the layer 11a is ≥1/2 of the total thickness of the substrate 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure-sensitive adhesive sheet for dicing. Further, the present invention relates to a method for dicing using the dicing pressure-sensitive adhesive sheet, and to-be-cut piece obtained by the dicing method.

  2. Description of the Related Art Conventionally, a semiconductor wafer made of silicon, gallium, arsenic, or the like is manufactured in a large diameter state, cut and separated (diced) into element pieces, further mounted, and then packaged. In this packaging, usually, a plurality of chips are packaged at a time, and this semiconductor package is further diced and picked up into individual semiconductor chips. The semiconductor package is subjected to a dicing process, a cleaning process, an expanding process, and a pick-up process in a state where the semiconductor package is adhered and fixed to the adhesive sheet. As the pressure-sensitive adhesive sheet, a sheet obtained by applying about 1 to 200 μm of an acrylic pressure-sensitive adhesive on a substrate made of a plastic film is generally used.

  The dicing process of a semiconductor package is usually performed using a round blade that moves while rotating. At that time, the cutting of the round blade is performed so as to reach the inside of the base material of the adhesive sheet for dicing that holds the semiconductor package. At this time, when cutting is performed to the inside of the base material of the pressure-sensitive adhesive sheet, cutting waste is generated in which the plastic film itself as the base material becomes a thread. When this thread-like waste adheres to the side surface of the package (object to be cut), the attached thread-like waste is mounted in a subsequent process as it is. As a result, there has been a problem that the filamentous waste causes the quality of the electronic circuit to be significantly reduced.

  The generation mechanism of filamentous waste is as follows. That is, as disclosed in Japanese Patent Application Laid-Open No. 2001-72947 (Patent Document 1), the dicing blade is heated by friction when cutting the object to be cut, and the base film is configured by cutting into the base film. The resin to be melted. The melted resin is wound up by the rotation of the dicing blade, and then cooled and solidified with cutting cooling water to become thread-like waste. In conventional silicon wafer dicing, for example, polypropylene as described in JP-A-11-43656 (Patent Document 2) and JP-A-2003-7654 (Patent Document 3) is used as a main constituent. The base film was effective in suppressing the generation of filamentous waste. It is presumed that this was because polypropylene had a high melting point and was hardly melted by a heated dicing blade.

  Further, as means for solving such a problem of filamentous waste, in addition to the above-described prior art, for example, the following JP-A-5-156214 (Patent Document 4) and JP-A-5-21234 (Patent Document 5) etc. Also disclosed is the method disclosed in.

  However, the prior arts disclosed in Patent Documents 2, 4 and 5 cannot solve the problem of the dicing of the semiconductor package even if the problem of the generation of the thread-like waste during the dicing of the silicon wafer can be solved.

  That is, in Japanese Patent Application Laid-Open No. 11-43656 (Patent Document 2), it is proposed to use an unstretched polypropylene film as a base film of an adhesive sheet. Although this method can suppress the generation of thread-like debris for dicing silicon wafers, as a result of studies by the inventors of the present application, it has been confirmed that the effect is not sufficient for dicing semiconductor packages. There was also a problem in workability such as lack of expandability.

  Japanese Patent Application Laid-Open No. 5-156214 (Patent Document 4) proposes an adhesive sheet using an ethylene-methacrylate copolymer as a base material. However, this pressure-sensitive adhesive sheet, although somewhat suppressing the generation of thread waste in silicon dicing, does not satisfy the required level in the production of semiconductor wafers. In addition, the semiconductor package dicing is not so effective.

  Japanese Patent Application Laid-Open No. 5-21234 (Patent Document 5) proposes an adhesive sheet using a crosslinked film in which a base film is irradiated with radiation such as an electron beam of 1 to 80 MRad or γ-ray. In the pressure-sensitive adhesive sheet, when the thickness of the base film is about 80 to 100 μm, an effect of suppressing the generation of filamentous waste to some extent in the dicing of the silicon wafer is recognized. However, when the thickness of the base film is 120 μm or more, particularly 150 to 300 μm, thread waste is generated when the semiconductor package is diced. This is because the outermost surface of the substrate film is crosslinked to some extent, but the inside of the substrate film is not sufficiently crosslinked by radiation.

JP 2001-72947 A Japanese Patent Laid-Open No. 11-43656 JP 2003-7654 A JP-A-5-156214 Japanese Patent Laid-Open No. 5-21234

  The present invention is intended to solve the problems associated with the prior art as described above, and provides a pressure-sensitive adhesive sheet for dicing that is free from degradation of product quality and cost disadvantages and that is less likely to generate thread waste during dicing. The purpose is to do. Furthermore, it aims at providing the dicing method using the said adhesive sheet for dicing.

  This inventor earnestly examined about the base film which comprises the adhesive sheet for dicing in order to solve the said subject. As a result, it has been found that by using a base film having a multilayer structure including an ethylene-based resin and having a layer having a melting point of 95 ° C. or less, the generation of filamentous waste during dicing can be reduced, and the present invention is completed. It came to.

  That is, in order to solve the above problems, the pressure-sensitive adhesive sheet for dicing according to the present invention is a pressure-sensitive adhesive sheet for dicing having a pressure-sensitive adhesive layer on at least one side of the base material, and the base material has a melting point of 95 ° C. or lower. It is a multilayer structure which has a layer containing these ethylene-type resin, The thickness of the said layer is 1/2 or more of the total thickness of a base material, It is characterized by the above-mentioned.

  Even when a dicing adhesive sheet having a base material mainly composed of a resin having a high melting point (for example, polypropylene) is used, for example, when a semiconductor package is diced, it is generated between the dicing blade and the object to be cut. The frictional heat may be higher than its melting point. This is because a semiconductor package is thicker than a silicon wafer or the like and a dicing blade having a large thickness is used, so that friction between the dicing blade and the semiconductor package is increased.

  The pressure-sensitive adhesive sheet for dicing according to the present invention uses a multilayer structure having a layer containing an ethylene-based resin having a melting point of 95 ° C. or lower as the base material, so that the melt viscosity at the time of melting of the base material is sufficiently lowered To. As a result, even when the layer is wound up by the rotation of the dicing blade, a state where the layer does not extend into a filament shape due to melt tension does not occur, and the occurrence of filamentous waste can be remarkably suppressed by enabling scattering like a liquid. it can.

  In order to solve the above problems, the pressure-sensitive adhesive sheet for dicing according to the present invention is a pressure-sensitive adhesive sheet for dicing having a pressure-sensitive adhesive layer on at least one side of the base material, and the base material has a melting point of 95 ° C. or lower. And a layer having a cross-linked structure on a side in contact with the pressure-sensitive adhesive layer.

  Even when the base material includes a layer containing an ethylene-based resin having a melting point of 95 ° C. or lower, when wound up by the rotation of a dicing blade, the melt viscosity at the time of melting of the layer is not sufficiently lowered, and the melt tension The so-called beard may be generated by extending into a thread shape. This is because when the dicing blade finishes cutting the object to be cut, the temperature of the dicing blade decreases due to the fact that the object to be cut is lost. Such whiskers are not in direct contact with the object to be cut, but when they are broken during dicing, they may adhere to the object to be cut, such as being washed with cutting water. However, as described above, by placing a layer having a cross-linked structure in a portion that is cut by a dicing blade, the generation of the beard as described above can be suppressed. In addition, even when the cutting depth of the dicing blade is large, a layer containing an ethylene-based resin having a melting point of 95 ° C. or lower is provided under the layer having a cross-linked structure. Can also be suppressed.

  In each of the above structures, the melt flow rate at 190 ° C. of the ethylene-based resin is preferably 1.5 g / 10 min or more.

  When the melt flow rate at 190 ° C. of the ethylene-based resin is 1.5 g / 10 min or more, the fluidity at the time of melting can be increased. As a result, the melt tension can be further reduced, and the resin constituting the layer can be further suppressed from extending into a thread shape.

  In each of the above structures, the total thickness of the base material is preferably 100 μm or more.

  The said structure makes the layer thickness of a base material 100 micrometers or more in order to give sufficient thickness to an adhesive sheet. Thereby, the dicing blade can be sufficiently cut into the adhesive sheet when dicing the semiconductor package. As a result, an adhesive sheet capable of improving the cutting quality with respect to the semiconductor package can be provided.

  In each of the above configurations, the pressure-sensitive adhesive layer is preferably configured to include a radiation curable pressure-sensitive adhesive.

  By using a pressure-sensitive adhesive layer formed of a radiation curable pressure-sensitive adhesive, the adhesive strength can be reduced by irradiating with radiation, and the semiconductor package and the like can be easily separated after being cut and separated. Can do.

  In order to solve the above-mentioned problem, the dicing method according to the present invention is a dicing method in which the object to be cut, to which the dicing adhesive sheet is bonded, is diced by cutting into the base material of the dicing adhesive sheet. The dicing pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on at least one side of the base material, and the base material has a multilayer structure having a layer containing an ethylene resin having a melting point of 95 ° C. or lower. A layer having a thickness of 1/2 or more of the total thickness of the substrate is used.

  In the above method, even if the layer on the adhesive layer side of the base material is melted by the frictional heat of the dicing blade during dicing, and the resin constituting the layer is wound up by the rotation of the dicing blade, the layer Since the melting point of the resin constituting the resin is 95 ° C. or less and the melt viscosity is sufficiently small, it is possible to reduce the elongation of the resin into a thread shape due to the melt tension. That is, since it scatters like a liquid, generation | occurrence | production of filamentous waste can be suppressed notably. As a result, for example, by mounting the thread-like scraps while adhering to the object to be cut, it is possible to suppress the quality of the object to be cut from being significantly lowered and to improve the yield.

  In order to solve the above-mentioned problem, the dicing method according to the present invention is a dicing method in which the object to be cut, to which the dicing adhesive sheet is bonded, is diced by cutting into the base material of the dicing adhesive sheet. The dicing pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on at least one side of the base material, and the base material has a multilayer structure having a layer containing an ethylene resin having a melting point of 95 ° C. or lower. And the thing provided with the layer which has a crosslinked structure in the side which touches the said adhesive layer is used, It is characterized by the above-mentioned.

  When using the method, as the pressure-sensitive adhesive sheet for dicing, since the substrate is provided with a layer having a crosslinked structure on the side in contact with the pressure-sensitive adhesive layer, when the dicing blade has finished cutting the object to be cut, Even when the temperature of the dicing blade is reduced due to the absence of the object to be cut, it is possible to suppress the occurrence of so-called whiskers. In addition, even when the cutting depth of the dicing blade is large, a layer containing an ethylene-based resin having a melting point of 95 ° C. or lower is provided under the layer having a crosslinked structure. Occurrence can also be suppressed. As a result, it is possible to improve the yield by suppressing the quality of the object to be cut significantly by mounting the whiskers and thread scraps while being attached to the object to be cut while dicing. .

  Each of the above methods can include a step of picking up a cut piece after cutting from the pressure-sensitive adhesive sheet for dicing after performing the dicing.

  Thereby, it becomes possible to perform from a dicing process to a pick-up process with the same adhesive sheet, and improvement of production efficiency can be aimed at.

  In each of the above methods, it is preferable to use a diamond blade having a metal as a bonding material for the dicing blade used in the dicing.

  According to the above method, if metal is used as the bonding material, the heat generated by cutting during dicing can be increased. Thereby, the melt viscosity of resin which comprises a layer whose melting | fusing point is 95 degrees C or less falls, and it can further suppress a filamentous waste production | generation.

  Further, when the object to be cut is a semiconductor package, the dicing method according to the present invention is most effective.

  With the above method, since the generation of thread waste is reduced, the yield can be improved without degrading the quality of the semiconductor device.

  Moreover, in order to solve the said subject, the to-be-cut | disconnected body piece which concerns on this invention is obtained by dicing the said to-be-cut | disconnected object in the dicing method as described above.

  The to-be-cut body piece manufactured by the dicing method described above has no quality of thread-like waste and has excellent quality.

The present invention has the following effects by the means described above.
That is, according to the present invention, by providing a layer containing an ethylene-based resin having a melting point of 95 ° C. or less on the pressure-sensitive adhesive layer side, generation of filamentous waste of the base material generated during dicing is reduced and yield is improved. be able to.

(Adhesive sheet for dicing)
The dicing adhesive sheet according to the embodiment of the present invention will be described below with reference to the drawings. However, parts that are not necessary for the description are omitted, and some parts are illustrated by being enlarged or reduced for easy explanation. FIG. 1A is a schematic cross-sectional view showing an outline of a dicing pressure-sensitive adhesive sheet (hereinafter referred to as a pressure-sensitive adhesive sheet) according to the present embodiment.

  As shown in FIG. 1A, the pressure-sensitive adhesive sheet 10 has a configuration in which a pressure-sensitive adhesive layer 12 and a separator 13 are sequentially laminated on one side of a base film 11.

  The base film (base material) 11 serves as a support base for the pressure-sensitive adhesive layer 12 and the like, and is a multilayer film composed of at least an inner layer 11a and an outer layer 11b. The inner layer 11 a is provided so as to face the pressure-sensitive adhesive layer 12.

  The inner layer 11a is a layer containing an ethylene resin having a melting point of 95 ° C. or lower. However, the melting point of the ethylene-based resin is preferably 40 ° C. or higher, and more preferably 70 ° C. or higher. This is because if the melting point is too low, film formation of the inner layer 11a and storage at room temperature may be difficult. The ethylene resin is not particularly limited. For example, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester copolymer, ionomer resin, polyurethane resin , A polybutadiene resin, a copolymer of ethylene and α-olefin, and the like. In addition, an ethylene- (meth) acrylic acid copolymer means an ethylene-acrylic acid copolymer and / or an ethylene-methacrylic acid copolymer, and (meth) in the present invention has the same meaning.

  Other constituent materials included in the inner layer 11a are not particularly limited, and examples thereof include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, SEBS, and SEPS.

  The outer layer 11b is not particularly limited, and examples thereof include low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polyester, polyvinyl chloride, ethylene-vinyl acetate copolymer, and ethylene- (meth) acrylic acid. Examples thereof include a copolymer, an ethylene- (meth) acrylic acid ester copolymer, an ionomer resin, and an ethylene-α olefin copolymer.

  The content of the ethylene resin is preferably 40% by weight or more, more preferably 50% by weight or more, and particularly preferably 60% by weight or more. By setting the content of the ethylene-based resin within the above range, the melt viscosity when the inner layer 11a is melted is sufficiently lowered. As a result, even if the inner layer 11a is wound up by the rotation of the dicing blade, the inner layer 11a is prevented from being elongated by melt tension.

  The ethylene resin preferably has a melt flow rate at 190 ° C. of 1.5 g / 10 min or more, and more preferably 2 g / 10 min or more. By setting the melt flow rate to 1.5 g / 10 min or more, the fluidity when the inner layer 11a is melted can be increased. However, the upper limit of the melt flow rate is 12 g / 10 min or less in consideration of the film formability of the film.

  It is preferable that the thickness of the base film 11 is usually in the range of 100 to 500 μm. However, in order to sufficiently cut the dicing blade in the pressure-sensitive adhesive sheet 10 at the time of dicing, the thickness is more preferably 120 μm or more in order to give the pressure-sensitive adhesive sheet 10 a sufficient thickness. This is to prevent the portion to be cut from being insufficiently diced and maintain the cutting quality at a high level.

  Here, it is preferable that the thickness of the inner layer 11 a is ½ or more of the total thickness of the base film 11. In consideration of the thickness of the base film 11, it is preferable that the thickness is in the range of 50 μm or more and less than 250 μm in more detail. Moreover, the inner layer 11a in the base film 11 needs to be provided at a position where the dicing blade reaches when the semiconductor package is diced. Therefore, from this viewpoint, the inner layer 11a is preferably in contact with the pressure-sensitive adhesive layer 12 and has a thickness of 80 μm or more.

  The base film 11 may be non-stretched or may be uniaxially or biaxially stretched as necessary. Further, the surface can be subjected to conventional physical or chemical treatment such as mat treatment, corona discharge treatment, primer treatment, and crosslinking treatment (chemical crosslinking (silane bonding)) as necessary.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 12, a pressure-sensitive pressure-sensitive adhesive generally used can be used. Specific examples include various pressure-sensitive adhesives such as acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and polyvinyl ethers. In particular, (meth) acrylic polymers are used as base polymers in terms of adhesion to semiconductor wafers and semiconductor packages as objects to be cut, and cleanability of semiconductor wafers after peeling with organic solvents such as ultrapure water and alcohol. A (meth) acrylic pressure-sensitive adhesive is preferred.

  Examples of the (meth) acrylic polymer include (meth) acrylic acid alkyl esters (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, Pentyl ester, isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, isononyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester , Hexadecyl ester, octadecyl ester, eicosyl ester, etc., and an alkyl group having 1 to 30 carbon atoms, particularly a linear or branched alkyl group having 4 to 18 carbon atoms. Tellurium), (meth) acrylic acid cycloalkyl esters (for example, cyclopentyl ester, cyclohexyl ester, etc.), (meth) acrylic acid hydroxyalkyl esters (for example, hydroxyethyl ester, hydroxybutyl ester, hydroxyhexyl ester, etc.), (meta ) Glycidyl acrylate, (meth) acrylic acid, itaconic acid, maleic anhydride, (meth) acrylic acid amide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl esters (eg, dimethyl) (Aminoethyl methacrylate, t-butylaminoethyl methacrylate, etc.), vinyl acetate, and (meth) acrylic polymers using one or more of styrene as monomer components.

  The (meth) acrylic polymer is a unit corresponding to another monomer component copolymerizable with the (meth) acrylic acid alkyl ester or cycloalkyl ester, if necessary, for the purpose of modifying cohesive force, adhesiveness and the like. May be included. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride Acid anhydride monomers such as itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; The Sulfonic acid groups such as lensulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid Containing monomers; Phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; acrylamide, acrylonitrile and the like. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 30% by weight or less, more preferably 15% by weight or less, based on the total monomer components.

  Furthermore, in order to crosslink the (meth) acrylic polymer, a polyfunctional monomer or the like can be included as a monomer component for copolymerization as necessary. By crosslinking the base polymer, the self-holding property of the pressure-sensitive adhesive layer is improved, so that a large deformation of the pressure-sensitive adhesive sheet can be prevented and the flat state of the pressure-sensitive adhesive sheet 10 can be easily maintained.

  Examples of multifunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and pentaerythritol di (Meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) acrylate, etc. Can be mentioned. These polyfunctional monomers can also be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

  The (meth) acrylic polymer can be obtained by polymerizing a single monomer or a mixture of two or more monomers. The polymerization can be carried out by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization. In particular, when polymerizing by irradiating radiation such as ultraviolet rays or electron beams, photopolymerization is performed by casting a liquid composition obtained by mixing a monomer component and a photopolymerization initiator in a urethane (meth) acrylate oligomer. It is preferable to synthesize a (meth) acrylic polymer.

  The urethane (meth) acrylate oligomer is a bifunctional compound having a number average molecular weight of about 500 to 100,000, preferably 1000 to 30,000, and having an ester diol as a main skeleton. Examples of the monomer component include morpholine (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and methoxylated cyclodecatriene (meth) acrylate. The mixing ratio of the urethane (meth) acrylate oligomer and the monomer component is preferably oligomer: monomer component = 95-5: 5-95 (% by weight), more preferably 50-70: 50-30 (weight). %). When the content of the urethane (meth) acrylate oligomer is large, the viscosity of the liquid composition tends to be high and polymerization tends to be difficult.

  The pressure-sensitive adhesive layer 12 preferably has a low content of a low molecular weight substance from the viewpoint of preventing contamination of the object to be cut. From this point, the number average molecular weight of the (meth) acrylic polymer is preferably about 200,000 to 3,000,000, more preferably about 250,000 to 1,500,000.

  Moreover, in order to increase the number average molecular weight of the (meth) acrylic polymer as a base polymer, an external cross-linking agent can be appropriately employed for the pressure-sensitive adhesive. Specific means for the external crosslinking method include a method of adding a so-called crosslinking agent such as a polyisocyanate compound, a melamine resin, a urea resin, an epoxy resin, a polyamine, a carboxyl group-containing polymer, and reacting them. When using an external cross-linking agent, the amount used is appropriately determined depending on the balance with the base polymer to be cross-linked, and further depending on the intended use as an adhesive. Generally, it is preferable to mix about 1 to 5 parts by weight with respect to 100 parts by weight of the base polymer. Furthermore, you may use additives, such as conventionally well-known various tackifiers and anti-aging agent other than the said component as needed, for an adhesive.

  Moreover, a radiation curable pressure sensitive adhesive can be used as the pressure sensitive adhesive. As the radiation-curable pressure-sensitive adhesive, those having a radiation-curable functional group such as a carbon-carbon double bond and exhibiting adhesiveness can be used without particular limitation. As the radiation curable pressure-sensitive adhesive, an ultraviolet curable pressure-sensitive adhesive whose adhesive strength is reduced by ultraviolet irradiation is desirable. According to the pressure-sensitive adhesive layer 12, the pressure-sensitive adhesive sheet 10 can be easily peeled off by ultraviolet irradiation after the back grinding (grinding) step or the dicing step.

  Examples of the ultraviolet curable adhesive include, for example, a copolymer (acrylic polymer) of a homopolymer of the (meth) acrylic acid ester or a copolymerizable comonomer and an ultraviolet curable component (carbon-carbon in the side chain of the acrylic polymer). A double bond may be added), a photopolymerization initiator, and, if necessary, conventional additives such as a crosslinking agent, a tackifier, a filler, an anti-aging agent, and a coloring agent. .

  The ultraviolet curable component may be any monomer, oligomer, or polymer that has a carbon-carbon double bond in the molecule and can be cured by radical polymerization. Specifically, for example, urethane oligomer, urethane (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate , Dipentaerystol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol Esters of (meth) acrylic acid and polyhydric alcohols such as di (meth) acrylate and dipentaerythritol hexa (meth) acrylate; ester acrylate oligomers; 2-propenyl di-3 Butenyl cyanurate, 2-hydroxyethyl bis (2-acryloxyethyl) isocyanurate, tris (2-methacryloxyethyl) isocyanurate or isocyanurate compounds such as isocyanurate. In addition, when using the ultraviolet curable polymer which has a carbon-carbon double bond in a polymer side chain as an acrylic polymer, it is not necessary to add the said ultraviolet curable component in particular. The compounding amount of the ultraviolet curable monomer component or oligomer component is, for example, 20 to 200 parts by weight, preferably 50 to 150 parts by weight with respect to 100 parts by weight of the base polymer such as (meth) acrylic polymer constituting the pressure-sensitive adhesive. Degree.

  In addition to the additive-type radiation-curable pressure-sensitive adhesive described above, the radiation-curable pressure-sensitive adhesive has a carbon-carbon double bond as a base polymer in the polymer side chain, main chain, or main chain terminal. Intrinsic radiation curable pressure-sensitive adhesives that use materials are listed. The intrinsic radiation curable pressure-sensitive adhesive does not need to contain an oligomer component or the like which is a low molecular component, or does not contain much, so that the oligomer component or the like does not move in the pressure-sensitive adhesive over time. Thereby, the adhesive layer 12 having a stable layer structure can be formed.

  As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, a polymer having a (meth) acrylic polymer as a basic skeleton is preferable. Examples of the basic skeleton of the (meth) acrylic polymer include the (meth) acrylic polymers exemplified above.

  Introducing a carbon-carbon double bond to the polymer side chain in the (meth) acrylic polymer facilitates molecular design. The method for introducing the carbon-carbon double bond is not particularly limited, and various methods can be adopted. For example, after a monomer having a functional group is previously copolymerized with a (meth) acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation of the carbon-carbon double bond. Examples of the method include a condensation or addition reaction while maintaining the curability.

  Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable from the viewpoint of easy reaction tracking. Moreover, if it is a combination which produces | generates the said (meth) acrylic-type polymer which has the said carbon-carbon double bond by the combination of these functional groups, a functional group will be any side of a (meth) acrylic-type polymer and the said compound However, in the preferable combination, it is preferable that the (meth) acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. Examples of the (meth) acrylic polymer include those obtained by copolymerization of the above-exemplified hydroxy group-containing monomers and ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, or diethylene glycol monovinyl ether. It is done.

  As the intrinsic radiation curable pressure-sensitive adhesive, the base polymer (particularly, (meth) acrylic polymer) having the carbon-carbon double bond can be used alone. Further, the radiation-curable monomer component or oligomer component can be blended to such an extent that the characteristics are not deteriorated. The amount of the radiation-curable oligomer component or the like is usually 30 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the base polymer.

  The polymerization initiator may be any substance that can be cleaved to generate radicals by irradiation with ultraviolet rays having an appropriate wavelength that can trigger the polymerization reaction. Specifically, for example, benzoin alkyl ethers such as benzoin methyl ether, benzoin isopropyl ether and benzoin isobutyl ether; aromatic ketones such as benzyl, benzoin, benzophenone and α-hydroxycyclohexyl phenyl ketone; benzyldimethyl Aromatic ketals such as ketals; polyvinyl benzophenones; thioxanthones such as chlorothioxanthone, dodecyl thioxanthone, dimethyl thioxanthone, and diethyl thioxanthone. The compounding quantity of a polymerization initiator is about 0.1-20 weight part with respect to 100 weight part of base polymers, such as (meth) acrylic-type polymer which comprises an adhesive, Preferably it is 1-10 weight part. .

  On the other hand, examples of the heat-peelable pressure-sensitive adhesive include a heat-foaming pressure-sensitive adhesive in which thermally expandable fine particles are blended with the general pressure-sensitive pressure-sensitive adhesive. After achieving the purpose of bonding the article, the pressure-sensitive adhesive containing the thermally expandable fine particles is heated, whereby the pressure-sensitive adhesive layer 12 is foamed or expanded to change the surface of the pressure-sensitive adhesive layer 12 into irregularities. The adhesive area is reduced by reducing the adhesion area, and the articles can be easily separated, and they are used for various purposes such as fixing electronic goods and their materials during processing, logistics for transportation, etc. Yes.

  There is no particular limitation on the thermally expandable fine particles, and various inorganic and organic thermally expandable microspheres are selected so that they have a combination of different peeling start temperatures, although those with a low peel start temperature and a high peel start temperature. Can be used. The difference in peeling start temperature between the two types of thermally expandable microspheres is appropriately determined according to the processing accuracy such as the temperature-sensitive characteristics of the thermally expandable microspheres, but is generally 20 to 70 ° C., preferably 30 to 30 ° C. The temperature difference is 50 ° C.

  The heat-expandable pressure-sensitive adhesive has a reduced adhesive area due to foaming of the heat-expandable fine particles by heat and can be easily peeled off. The heat-expandable fine particles preferably have an average particle diameter of about 1 to 25 μm. More preferably, it is 5-15 micrometers, and the thing of about 10 micrometers is especially preferable.

  As the heat-expandable fine particles, a material that expands under heating can be used without particular limitation. However, expandable fine particles obtained by microencapsulating a heat-expandable substance are preferably used from the viewpoint of easy mixing operation. For example, it may be a microsphere in which a substance that easily expands by gasification by heating, such as isobutane, propane, or pentane, is encapsulated in an elastic shell. The grain is usually formed of a thermoplastic material, a hot-melt material, a material that bursts due to thermal expansion, or the like. Examples of the substance forming the shell include vinylidene chloride-acrylonitrile copolymer, polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile, polyvinylidene chloride, and polysulfone. Thermally expansible microcapsules also have advantages such as excellent dispersibility with the pressure-sensitive adhesive. Examples of commercially available thermal expandable microcapsules include microspheres (trade name: manufactured by Matsumoto Yushi Co., Ltd.). In addition, you may add a thermal expansion auxiliary agent as needed.

  The blending amount of the thermally expandable fine particles (thermally expandable microcapsules) with respect to the pressure-sensitive adhesive can be appropriately determined according to the type of the pressure-sensitive adhesive layer 12 so that the adhesive strength can be reduced. In general, the amount of the pressure-sensitive adhesive layer 12 containing thermally expandable fine particles is preferably 60% or more, preferably 70% or more, more preferably 80% or more of the thickness immediately after thermal expansion. Moreover, it is about 1-100 weight part with respect to 100 weight part of base polymers, Preferably it is 5-40 weight part, More preferably, it is 10-20 weight part.

  The thickness of the pressure-sensitive adhesive layer 12 is preferably 1 μm to 100 μm, more preferably about 5 μm to 50 μm, from the viewpoint of achieving both adhesive fixability and peelability. The adhesive force of the pressure-sensitive adhesive layer 12 is not particularly limited as long as it is within a range that can be finally easily peeled off from the support wafer. For example, the 180 degree peel adhesion value to the semiconductor wafer is preferably in the range of 1 to 30 N / 10 mm, and more preferably in the range of 5 to 20 N / 10 mm.

  The separator 13 is provided as needed for label processing or for the purpose of smoothing the surface of the pressure-sensitive adhesive layer 12. Examples of the constituent material for the separator 13 include synthetic resin films such as paper, polyethylene, polypropylene, and polyethylene terephthalate. In order to improve the peelability from the pressure-sensitive adhesive layer 12, the surface of the separator 13 may be subjected to a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment as necessary. Further, if necessary, an ultraviolet ray prevention treatment may be performed so that the adhesive sheet 10 does not react with environmental ultraviolet rays. The thickness of the separator 13 is usually about 10 to 200 μm, preferably about 25 to 100 μm.

  When the pressure-sensitive adhesive layer 12 is made of a radiation curable pressure-sensitive adhesive such as ultraviolet rays, the base film 11 has sufficient radiation transparency because the pressure-sensitive adhesive layer 12 is irradiated before or after dicing. Need to be.

  The inner layer 11a is a soft layer as compared with a normal base material or the like. For this reason, when the pressure-sensitive adhesive sheet 10 is once wound into a roll after the pressure-sensitive adhesive sheet 10 is manufactured, blocking (fusion of the back surface of the base film 11 (outer layer 11b) and the pressure-sensitive adhesive layer 12) is caused. Sometimes. Therefore, for the purpose of preventing blocking, a layer for suppressing the occurrence of blocking may be provided on the outer side of the outer layer 11b. The layer that suppresses the occurrence of blocking is not particularly limited, and examples thereof include a layer subjected to an embossing process. Moreover, you may provide another layer on the opposite side to the side in which the adhesive layer 12 of the base film 11 is provided for the objective similar to the above, or the objective of an expandability improvement.

  Next, an adhesive sheet according to another embodiment of the present invention will be described. FIG.1 (b) is a cross-sectional schematic diagram which shows the outline of the said adhesive sheet. The adhesive sheet 10 ′ shown in FIG. 1 (b) has a base film 11 ′ provided with a layer 11c having a cross-linked structure (hereinafter referred to as a cross-linked layer) in place of the base film 11 as compared with the adhesive sheet 10. The point used is different.

  Examples of the crosslinked layer 11c include a polyolefin film having a crosslinked structure. The material constituting the polyolefin film is not particularly limited. For example, polyethylene, polypropylene, polymethylpentene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene-methyl (meth) acrylic acid. Examples include esters, ethylene-ethyl (meth) acrylic acid copolymers, ethylene / vinyl alcohol copolymers, polybutenes, ethylene-ionomer copolymers, and the like. These constituent materials may be used individually by 1 type, and may use 2 or more types together. Furthermore, the crosslinked layer 11c is not limited to a single layer, and may be composed of a plurality of layers.

  The thickness of the cross-linked layer 11c is set in consideration of the cutting depth at the time of dicing, and is preferably 20 μm or more and 150 μm or less. Furthermore, when considering the change in crosslink density in the thickness direction, it is more preferably 20 μm or more and 100 μm or less, particularly preferably 20 μm or more and less than 40 μm.

  As a method of forming the crosslinked layer 11c, a polyolefin film made of the above-mentioned constituent material is preliminarily irradiated with an electron beam or γ-ray to be crosslinked, and this film is laminated on the inner layer 11a by dry lamination or the like. And other films can be formed by a co-extrusion method, and further irradiated with an electron beam or the like to crosslink the polyolefin film to form a crosslinked layer 11c. The crosslinked layer 11c formed by these methods has a crosslinked structure in which the crosslinking density gradually decreases as the distance from the irradiated surface increases in the thickness direction.

  The crosslinking density of the crosslinked layer 11c can be controlled by appropriately changing the electron beam or γ-ray irradiation amount. The electron beam or γ-ray irradiation amount is usually in the range of 10 to 250 Mrad, preferably 20 to 200 Mrad, and particularly preferably 30 to 150 Mrad. Moreover, when the crosslinked layer 11c consists of polyethylene, it is preferable that an electron beam or a gamma ray irradiation amount is about 30-150 Mrad. Furthermore, when the crosslinked layer 11c is made of an ethylene copolymer, the electron beam or γ-ray irradiation amount is preferably about 20 to 100 Mrad.

  Here, the electron beam refers to a free electron flux, that is, a cathode beam. Specifically, the electron beam irradiation is performed using an electron beam accelerator (including any type such as high energy, low energy, and scanning) under a predetermined condition under the generated electron beam under a polyolefin film. This is done by passing.

In addition, γ-ray refers to a kind of electromagnetic wave that is emitted when radioactive elements decay, as is usually defined. Specifically, the irradiation of γ rays is performed by placing a polyolefin film in an irradiation chamber having Co ⁶⁰ as a radiation source and irradiating a predetermined amount of γ rays. In this case, since the polyolefin film can be processed in a roll shape, the workability is good.

  When the polyolefin film is irradiated with an electron beam or γ-ray with such an irradiation amount, generation of filamentous waste during dicing can be reduced. Further, the expansion of the pressure-sensitive adhesive sheet 10 ′ can be performed without hindering the mechanical properties such as elasticity and strength of the base film 11 ′. On the other hand, if the amount of electron beam or γ-ray irradiation is less than 1 Mrad, the effect of electron beam or γ-ray irradiation is insufficient, and a large amount of filamentous waste is generated during dicing as in the case of non-irradiation. is there. Moreover, when the electron beam or γ-ray irradiation dose exceeds 80 Mrad, mechanical properties such as elasticity and strength of the base film 11 ′ may be impaired, and the base film 11 ′ may be broken at the time of expanding. The base film 11 ′ after irradiation may be deteriorated.

(Method for producing adhesive sheet)
Next, the manufacturing method of the adhesive sheet which concerns on this Embodiment is demonstrated. In the following description, the case where the adhesive sheet 10 is used is taken as an example.

  The base film 11 can be formed by a conventionally known film forming method. Examples of the film forming method include a calendar film forming method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, a co-extrusion method, and a dry lamination method.

  Next, a composition containing an adhesive is applied on the inner layer 11a of the base film 11 and dried (heat-crosslinked if necessary) to form the adhesive layer 12. When there is another layer on the inner layer 11a, the pressure-sensitive adhesive layer 12 is formed on the other layer. Examples of the coating method include roll coating, screen coating, and gravure coating. Moreover, application | coating may be performed directly on a base material, and you may transfer to a base material, after apply | coating to the release paper etc. which performed the peeling process on the surface. Subsequently, the pressure-sensitive adhesive sheet 10 according to this embodiment can be obtained by pasting the separator 13 on the surface of the pressure-sensitive adhesive layer 12.

(Dicing method)
Next, the dicing method according to the present invention will be described taking as an example the case where the object to be cut is a semiconductor package.

  As shown in FIGS. 2A to 2E, the dicing method according to the present embodiment includes a step of bonding the adhesive sheet 10 to the lead frame 14, a step of mounting the semiconductor chip 15, and a bonding wire 16. It includes at least a step of wire bonding, a step of sealing with a sealing resin 17, and a step of dicing the semiconductor package 21 as a sealed structure.

  The step of attaching the adhesive sheet 10 to the lead frame 14 is performed by first separating the separator 13 from the adhesive sheet 10 and aligning the lead frame 14 and the adhesive sheet 10. Bonding can be performed by a conventionally known method.

  As shown in FIGS. 2A and 2B, the semiconductor chip 15 is mounted on the die pad 14c of the metal lead frame 14 in which the adhesive sheet 10 is bonded to the outer pad side (the lower side of the figure). This is a step of bonding the semiconductor chip 15.

  The lead frame 14 is formed by engraving a terminal pattern of QFN using, for example, a metal such as copper, and the electrical contact portion is coated (plated) with a material such as silver, nickel, palladium, or gold. There may be. The thickness of the lead frame 14 is generally 100 to 300 μm. Note that this does not apply to portions that are partially thinned by etching or the like.

  The lead frame 14 preferably has an arrangement pattern in which individual QFNs are arranged in an orderly manner so that the lead frame 14 can be easily separated in a subsequent cutting step. For example, an arrangement pattern or the like arranged in a vertical and horizontal matrix on the lead frame 14 is called a matrix QFN or MAP-QFN, and is one aspect of the most preferable lead frame shape. In particular, in recent years, in order to increase the number of packages arranged in one lead frame from the viewpoint of productivity, not only these individual packages are miniaturized, but a large number of packages can be formed by one sealing portion. The number of these arrays has been greatly expanded so that sealing can be performed.

  As shown in FIG. 2A, in the package pattern region of the lead frame 14, a QFN substrate design in which a plurality of terminal portions 14b are arranged in a plurality of adjacent openings 14a is arranged in an orderly manner. In the case of a general QFN, each substrate design includes a terminal portion 14b having an outer lead surface on the lower side, a die pad 14c disposed at the center of the opening 14a, and a die pad 14c arranged around the opening 14a. The diver 11d is supported at the four corners of the opening 14a.

  The pressure-sensitive adhesive sheet 10 is preferably attached at least to the outside of the package pattern region and attached to a region including the entire circumference outside the resin-encapsulated region to be resin-sealed. Usually, the lead frame 14 has a guide pin hole for positioning at the time of resin sealing in the vicinity of the end side, and it is preferable that the lead frame 14 is adhered to a region where it is not blocked. Further, since a plurality of resin sealing regions are arranged in the longitudinal direction of the lead frame 14, it is preferable that the adhesive sheet 10 is continuously attached so as to cross the plurality of regions.

  On the lead frame 14 as described above, a semiconductor chip 15, that is, a silicon wafer chip as a semiconductor integrated circuit portion is mounted. A fixing area called a die pad 14c is provided on the lead frame 14 to fix the semiconductor chip 15. Bonding (fixing) to the die pad 14 c is performed using the conductive paste 19. However, the present invention is not limited to this method, and various methods using an adhesive tape or an adhesive can also be employed. When die bonding is performed using the conductive paste 19, a thermosetting adhesive, or the like, generally heat curing is performed at a temperature of about 150 to 200 ° C. for about 30 to 90 minutes.

  In the wire bonding step, as shown in FIG. 2C, the tip of the terminal portion 14 b (inner lead) of the lead frame 14 and the electrode pad 15 a on the semiconductor chip 15 are electrically connected by the bonding wire 16. It is a process. For example, a gold wire or an aluminum wire is used as the bonding wire 16. In this step, generally, the wire is connected by a combination of vibration energy by ultrasonic waves and pressure bonding energy by applying pressure while being heated to 120 to 250 ° C. At that time, the surface of the pressure-sensitive adhesive sheet 10 adhered to the lead frame 14 can be securely fixed to the heat block by vacuum suction.

  The sealing step is a step of sealing one side of the semiconductor chip side with a sealing resin 17 as shown in FIG. This process is performed to protect the semiconductor chip 15 and the bonding wire 16 mounted on the lead frame 14, and is molded in a mold using a sealing resin 17 including an epoxy resin. Is representative. At that time, it is general that a sealing process is performed simultaneously with a plurality of sealing resins 17 using a mold composed of an upper mold and a lower mold having a plurality of cavities. Specifically, for example, the heating temperature at the time of resin sealing is 170 to 180 ° C. After curing at this temperature for several minutes, post mold curing is further performed for several hours. In addition, it is preferable to peel the adhesive sheet 10 before post mold curing.

  The dicing process is a process in which the semiconductor package 21 is fully cut and divided into individual semiconductor devices. In the dicing, for example, a dicing blade or the like is used to cut from the cut portion of the sealing resin to reach the inner layer 11a in the base film 11. At this time, frictional heat is generated in the dicing blade due to friction with the semiconductor package. Thereby, the dicing blade is heated to a temperature exceeding the melting point of the inner layer 11a. As a result, the inner layer 11a melts, but its melting point is lower than that of a normal base material. For this reason, the resin constituting the inner layer 11a wound up by the dicing blade is cooled by the cutting cooling water and is scattered like a liquid without growing into filamentous waste. As a result, a conventional process for inspecting and removing filamentous waste is not required, or process work can be reduced.

  The dicing conditions are appropriately set according to the object to be cut. However, the dicing blade needs to be cut from the surface of the pressure-sensitive adhesive layer 12 to a position having a depth of 70 μm or more. This is because the inner layer 11a in the base film 11 is provided at this position. Note that the temperature of the cutting cooling water is usually in the range of 10 to 30 ° C.

  Here, as the dicing blade, as shown in FIGS. 3A and 3B, a bond material 33 using a metal such as a nickel alloy, and dispersed and held in the form of sandpaper on the bond material 33. It is preferable to use a diamond blade 31 having a plurality of formed diamond particles 32 (2 to 6 μm). When dicing is performed using the diamond blade 31, since the bonding material 33 is made of metal, the frictional heat due to cutting becomes particularly large. As a result, the melt viscosity of the inner layer 11a can be further reduced, which is effective in suppressing the formation of filamentous waste.

  In addition, in this invention, after dicing, the process of picking up the semiconductor element as a to-be-cut body piece from the adhesive sheet 10 for dicing may be included. The pickup method is not particularly limited, and various conventionally known methods can be employed. For example, a method of pushing up individual semiconductor elements from the pressure-sensitive adhesive sheet 10 side (lower side) with a needle and picking up the pushed-up semiconductor elements with a pickup device can be used.

  In the present embodiment, the semiconductor package 21 has been described as an example of the object to be cut, but the present invention is not limited to this. Examples of the object to be cut include a silicon wafer, a compound semiconductor wafer, and glass in addition to the semiconductor package 21. Moreover, when using these to-be-cut bodies, bonding with the adhesive sheet 10 can be performed by a conventionally well-known method.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to them, but are merely illustrative examples, unless otherwise specified.

Example 1
First, 95 parts by weight of butyl acrylate and 5 parts by weight of acrylic acid were copolymerized in a conventional manner in ethyl acetate. To a solution containing the obtained acrylic copolymer (number average molecular weight 800,000), 70 parts by weight of dipentaerythritol hexaacrylate (trade name “Kayarad DPHA”, manufactured by Nippon Kayaku Co., Ltd.), radical polymerization initiator ( Add 3 parts by weight of the trade name “Irgacure 651”, manufactured by Ciba Specialty Chemicals, and 5 parts by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane) to prepare an acrylic UV-curable adhesive solution. It was adjusted. This solution was applied to a silicone-treated surface of a polyester separator (separator) and heated at 800 ° C. for 10 minutes for heat crosslinking. As a result, an ultraviolet curable pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) having a thickness of 20 μm was formed.

  Next, a base film (base material) was produced. That is, ethylene-vinyl acetate copolymer (EVA) resin (melting point 84 ° C., melt flow rate 2.5 g / 10 min) and low density polyethylene (LDPE) resin (melting point 110 ° C., melt flow rate 2.3 g / 10 min) Was formed by T-die coextrusion method so that EVA layer (inner layer) / LDPE layer (outer layer) = 120 μm / 30 μm. Further, corona treatment was performed on the EVA layer side. The melt flow rate was measured according to JIS K7210. The measurement conditions were a test temperature of 190 ° C. and a load of 21.18 N.

  Subsequently, the pressure-sensitive adhesive layer provided on the polyester separator and the corona-treated surface of the base film were bonded to each other so as to face each other. In this way, an ultraviolet curable semiconductor package dicing pressure-sensitive adhesive sheet according to Example 1 was produced.

(Example 2)
First, in the same manner as in Example 1, an ultraviolet curable pressure-sensitive adhesive layer was formed on a polyester separator. Next, ethylene-ethyl acrylate copolymer (EEA) resin (melting point 92 ° C., melt flow rate 5 g / 10 min) and low density polyethylene (LDPE) resin (melting point 110 ° C., melt flow rate 3.5 g / 10 min) Was formed by T-die coextrusion method so that EEA layer (inner layer) / LDPE layer (outer layer) = 150 μm / 50 μm. Furthermore, the EEA layer side was subjected to corona treatment to produce a base film. Subsequently, the pressure-sensitive adhesive layer provided on the polyester separator and the corona-treated surface of the base film were bonded to each other so as to face each other. Thus, an ultraviolet curable semiconductor package dicing pressure-sensitive adhesive sheet according to Example 2 was produced.

(Example 3)
In the same manner as in Example 1, an ultraviolet curable pressure-sensitive adhesive layer was formed on the polyester separator. Next, low density polyethylene (LDPE) resin (melting point 110 ° C., melt flow rate 2 g / 10 min) and ethylene-vinyl acetate copolymer (EVA) resin (melting point 84 ° C., melt flow rate 2.5 g / 10 min). The film was formed by the T-die coextrusion method so that LDPE layer / EVA layer (inner layer) / LDPE layer (outer layer) = 70 μm / 100 μm / 30 μm. Further, the LDPE layer having a thickness of 70 μm was irradiated with an electron beam to be crosslinked to prepare a base film. The irradiation condition was an irradiation amount of 100 Mrad. Subsequently, the pressure-sensitive adhesive layer provided on the polyester separator and the LDPE layer having a thickness of 70 μm were bonded to each other so as to face each other. As a result, an ultraviolet curable semiconductor package dicing pressure-sensitive adhesive sheet according to Example 3 was produced.

(Comparative Example 1)
As a base film, a low-density polyethylene (LDPE) resin (melting point 110 ° C., melt flow rate 2 g / 10 min) is used to form a film having a thickness of 150 μm by a T-die extrusion method, and one side thereof is corona-treated. A UV-curable semiconductor package dicing pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the above-described one was used.

(Comparative Example 2)
As a base film, an EVA resin (melting point: 103 ° C., melt flow rate: 2 g / 10 min) was formed to a thickness of 200 μm while performing a mat treatment on one side by a T-die extrusion method. An ultraviolet curable semiconductor package dicing pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the one subjected to the corona treatment was used.

(Comparative Example 3)
A low-density polyethylene (LDPE) resin (melting point: 110 ° C., melt flow rate: 2 g / 10 min) is formed as a base film to a thickness of 200 μm by T-die extrusion, and one surface is irradiated with an electron beam did. The irradiation condition was an irradiation amount of 100 Mrad. An ultraviolet curable semiconductor package dicing pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except that the base film thus obtained was used.

(Evaluation test)
Each dicing pressure-sensitive adhesive sheet produced in each example and comparative example was evaluated by the following method. That is, a 10 cm × 10 cm epoxy substrate having a thickness of 1.0 mm was mounted on a dicing adhesive sheet, and dicing was performed under the following conditions.

Dicing condition Dicer: DFD-651 made by DISCO
Dicing blade: BIA801DC320N50M51 made by DISCO
Dicing blade rotation speed: 45,000 rpm
Dicing speed: 50mm / sec
Dicing depth: 100 μm from the adhesive sheet surface
Dicing size: 5 × 5mm
Cut mode: Down cut

  The cutting line after cutting by dicing was observed with an optical microscope (100 times), and the number of filaments on the epoxy substrate and the portion without the epoxy substrate on the adhesive sheet was counted. The results are shown in Table 1 below. As can be seen from Table 1, the pressure-sensitive adhesive sheet according to each of Examples 1 to 3 has little generation of thread-like waste, and practically less than 30 occurrences of thread-like waste when a 10 × 10 cm size substrate is diced at 5 × 5 mm. Was at a possible level. On the other hand, the pressure-sensitive adhesive sheets according to Comparative Examples 1 and 2 produced extremely large amounts of filamentous waste, and were not at a practical level.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows the outline of the adhesive sheet for dicing which concerns on this invention, Comprising: The same figure (a) represents the case where a base film consists of an inner layer and an outer layer, The same figure (b) is a base film, and a migration prevention This represents the case with layers. It is a cross-sectional schematic diagram which shows the outline of the adhesive sheet for dicing which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram for demonstrating the dicing blade which concerns on one Embodiment of this invention, Comprising: The figure (a) shows a dicing blade and the figure (b) shows the principal part of a dicing blade.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 'Dicing adhesive sheet 11, 11' Base film 11a Inner layer 11b Outer layer 11c Crosslinking layer 12 Adhesive layer 13 Separator 14 Lead frame 14a Opening 14b Terminal part 14c Die pad 14d Diver 15 Semiconductor chip 15a Electrode pad 16 Bonding wire 17 Sealing resin 19 Conductive paste 21 Semiconductor package 31 Diamond blade 32 Diamond particle 33 Bond material

Claims (11)

A pressure-sensitive adhesive sheet for dicing having a pressure-sensitive adhesive layer on at least one side of a substrate,
The base material has a multilayer structure having a layer containing an ethylene-based resin having a melting point of 95 ° C. or less,
A pressure-sensitive adhesive sheet for dicing, wherein the thickness of the layer is ½ or more of the total thickness of the substrate. A pressure-sensitive adhesive sheet for dicing having a pressure-sensitive adhesive layer on at least one side of a substrate,
The base material has a multilayer structure having a layer containing an ethylene-based resin having a melting point of 95 ° C. or less, and has a layer having a cross-linked structure on the side in contact with the pressure-sensitive adhesive layer. Sheet.   The pressure-sensitive adhesive sheet for dicing according to claim 1 or 2, wherein a melt flow rate at 190 ° C of the ethylene-based resin is 1.5 g / 10 min or more.   The total thickness of the said base material is 100 micrometers or more, The adhesive sheet for dicing of any one of Claims 1-3 characterized by the above-mentioned.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer comprises a radiation-curable pressure-sensitive adhesive. A dicing method for dicing the workpiece to which the pressure-sensitive adhesive sheet for dicing is bonded to the base material of the pressure-sensitive adhesive sheet for dicing,
The dicing pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on at least one side of the substrate,
The base material has a multilayer structure having a layer containing an ethylene-based resin having a melting point of 95 ° C. or less,
A dicing method characterized in that a layer having a thickness of 1/2 or more of the total thickness of the substrate is used. A dicing method for dicing the workpiece to which the pressure-sensitive adhesive sheet for dicing is bonded to the base material of the pressure-sensitive adhesive sheet for dicing,
The dicing pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on at least one side of the substrate,
The base material has a multilayer structure having a layer containing an ethylene-based resin having a melting point of 95 ° C. or lower, and a base material having a cross-linked structure on the side in contact with the pressure-sensitive adhesive layer. Dicing method.   The dicing method according to claim 6, further comprising a step of picking up a cut piece after cutting from the dicing pressure-sensitive adhesive sheet after performing the dicing.   The dicing method according to any one of claims 6 to 8, wherein a diamond blade using a metal as a bonding material is used as a dicing blade used in the dicing.   The dicing method according to claim 6, wherein the object to be cut is a semiconductor package. The dicing method according to any one of claims 6 to 10, wherein a cut piece obtained by dicing the cut object.

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