JP2014022476A - Dicing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dicing sheet that is reduced in possibility of occurrence of adhesive remaining phenomenon.SOLUTION: There is provided a dicing sheet 1 including a base material 2 and an adhesive layer 3 laminated on at least one surface of the base material 2. The adhesive layer 3 is formed of an adhesive composition containing: a polymer (a1) having a hydroxyl group; an isocyanate-based crosslinking agent (a2); an energy ray polymerizable compound (B); and a tackifier resin (C). Here, a ratio of NCO/OH as a ratio of the total amount (unit: mol) of an isocyanate group that the isocyanate-based crosslinking agent (a2) contained in the adhesive composition has to the total amount (unit: mol) of a hydroxyl group that components except the isocyanate-based crosslinking agent (a2) contained in the adhesive composition have is 4-15.

Description

  The present invention relates to a dicing sheet used when dicing a semiconductor package in which a plurality of semiconductor chips are sealed with a resin.

A semiconductor component in which a semiconductor chip is resin-sealed (referred to as “mold chip” in this specification) is usually manufactured as follows.
First, a semiconductor chip is mounted on each base of an assembly formed by connecting a plurality of bases such as a TAB tape, and these semiconductor chips are collectively sealed with an electronic component assembly (this specification) (Referred to as “semiconductor package”). Next, the semiconductor package is fixed to the dicing sheet by attaching an adhesive sheet (referred to as a “dicing sheet” in this specification) including a base material and an adhesive layer on one surface of the semiconductor package. . The semiconductor package fixed to the dicing sheet is cut and separated (diced) into individual pieces, and a member in which a plurality of mold chips are arranged close to each other on the dicing sheet is manufactured (dicing step).

  Usually, the pressure-sensitive adhesive layer of the dicing sheet is designed so that the adhesiveness of the pressure-sensitive adhesive layer is reduced by a specific stimulus, and for example, energy ray irradiation is adopted as the specific stimulus. The operation of irradiating the dicing sheet with energy rays to reduce the adhesiveness of the pressure-sensitive adhesive layer is performed after the dicing operation in the dicing step and before the pickup step described later is started.

  The dicing sheet in the above member produced by the dicing process is expanded (extends in the main surface direction) to widen the interval between the mold chips arranged on the dicing sheet (expanding process). The mold chips thus separated from each other on the dicing sheet are individually picked up, separated from the dicing sheet (pickup process), and transferred to the next process. Since the energy ray irradiation for reducing the adhesiveness of the pressure-sensitive adhesive layer is performed before the pickup process is started, the pickup is facilitated.

  Of these series of steps, in the dicing step and the subsequent expanding step, the semiconductor package and the mold chip formed by dicing the semiconductor package are required to maintain a fixed state on the dicing sheet. From the viewpoint of achieving this object, the pressure-sensitive adhesive layer of the dicing sheet has adhesiveness before irradiation with energy rays to the semiconductor package and the mold chip. Or the adhesiveness of the adhesive layer before energy beam irradiation with respect to a mold chip | tip is preferable.

  Here, when the adherend of the dicing sheet is a semiconductor package and a mold chip, the unevenness of the adherend surface tends to be larger than when the semiconductor chip is an adherend. For this reason, if a dicing sheet having a semiconductor chip as an adherend is diverted as a dicing sheet used in the above-described series of processes for a semiconductor package, the adhesiveness to the adherend becomes insufficient, and the semiconductor package is cut in the dicing process. The mold chip separated into pieces peels off from the dicing sheet and scatters, and when the dicing sheet is stretched in the expanding process, the mold chip peels off from the dicing sheet and scatters. Hereinafter, these defects occurring in the dicing process and the expanding process are collectively referred to as “mold chip scattering”.

  For the purpose of reducing the possibility of this mold chip scattering, as described in Patent Documents 1 and 2, for example, a resin material for imparting adhesiveness to the adhesive layer of the dicing sheet (in this specification, And “tackifying resin”).

Japanese Patent No. 4861081 Japanese Patent No. 4040706

  By including a tackifying resin, the adhesiveness of the pressure-sensitive adhesive layer is improved and mold chip scattering is less likely to occur. However, since the pressure-sensitive adhesive layer is softened, the pressure-sensitive adhesive layer of the dicing sheet is formed on the ring frame when the dicing sheet is peeled off from the ring frame for fixing it after the pickup process is completed. It has been clarified that a phenomenon that the material to remain (also referred to as “adhesive sticking phenomenon” in this specification) occurs. If a new dicing sheet is fixed with the ring frame without removing the adhesive remaining on the ring frame, the fixing uniformity is lost, and the working stability of the dicing process is lowered. For this reason, it is necessary to remove the remaining pressure-sensitive adhesive, and this removal step causes a reduction in mold chip productivity.

  Then, this invention makes it a subject to provide the dicing sheet with which possibility that the adhesive sticking phenomenon will arise was reduced, and the manufacturing method of the mold chip using the dicing sheet.

  As a result of the study by the present inventors to achieve the above object, the adhesive sticking phenomenon described above is caused between the base material of the dicing sheet and the adhesive layer when the dicing sheet attached to the ring frame is peeled off. It was revealed that this may occur because of interfacial peeling. As a result of further examination based on this knowledge, it is possible to make the adhesive sticking phenomenon less likely to occur by a method such as containing a large amount of an isocyanate-based crosslinking agent in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer. And gained knowledge.

  The present invention completed based on such knowledge is, firstly, a dicing sheet comprising a base material and an adhesive layer laminated on at least one surface of the base material, the adhesive layer comprising: A pressure-sensitive adhesive composition comprising a polymer (a1) having a hydroxyl group, an isocyanate-based crosslinking agent (a2), an energy beam polymerizable compound (B) and a tackifier resin (C), wherein the pressure-sensitive adhesive Components other than the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition have the total amount (unit: mol) of isocyanate groups contained in the isocyanate-based crosslinking agent (a2) contained in the agent composition. Provided is a dicing sheet having an NCO / OH ratio of 4 or more and 15 or less relative to the total amount of hydroxyl groups (unit: mol) (Invention 1).

  When the NCO / OH ratio is in the above range, the possibility that an interaction involving the isocyanate group of the isocyanate-based crosslinking agent (a2) at the interface between the base material and the pressure-sensitive adhesive layer is increased. This interaction increases the adhesiveness of the pressure-sensitive adhesive layer to the base material (keying is improved). Therefore, when the NCO / OH ratio is in the above range, a pressure-sensitive adhesive sticking phenomenon occurs when a dicing sheet is used. The possibility is reduced.

  In the said invention (invention 1), content of the said isocyanate type crosslinking agent (a2) contained in the said adhesive composition is 2 mass parts or more with respect to 100 mass parts of polymers (a1) which have the said hydroxyl group. It is preferably 14 parts by mass or less (Invention 2). In this case, it becomes easy to set the NCO / OH ratio in the above range (4 to 15).

  In the said invention (invention 1 and 2), it is preferable that the hydroxyl value of the whole components other than the said isocyanate type crosslinking agent (a2) contained in the said adhesive composition is 2 mgKOH / g or more (invention 3). In this case, when the NCO / OH ratio is adjusted to the above range (4 to 15), it is more stably realized that the adhesive sticking phenomenon hardly occurs.

  In the said invention (invention 1 to 3), it is preferable that the thickness of the said adhesive layer is 5 micrometers or more and 35 micrometers or less (invention 4). When the thickness of the pressure-sensitive adhesive layer is in the above range, the possibility that the adhesiveness of the pressure-sensitive adhesive layer varies or the cohesive failure inside the pressure-sensitive adhesive layer during pickup is more stably reduced. The

  In the said invention (invention 1 to 4), it is preferable that an isocyanate-reactive group exists in the state before the said adhesive layer is laminated | stacked in the surface by which the said adhesive layer of the said base material is laminated | stacked. (Invention 5). The presence of an isocyanate-reactive group, which is a group having reactivity with an isocyanate group, may cause an interaction, particularly a chemical interaction, between the isocyanate group in the adhesive layer and the isocyanate-reactive group of the substrate. Sexuality increases. As a result, the keying of the pressure-sensitive adhesive layer with respect to the base material becomes easier to improve, and the possibility of the pressure-sensitive adhesive sticking phenomenon occurring is more stably reduced.

  In the said invention (invention 5), it is preferable that the said isocyanate reactive group contains 1 type, or 2 or more types chosen from the group which consists of a carboxyl group, a hydroxyl group, an amino group, and a thiol group (invention 6). When the isocyanate-reactive group is the above-mentioned functional group, a bond structure based on the reaction between the functional group and the isocyanate group is likely to be formed. Can be made.

  In the said invention (invention 5 and 6), the surface by which the said adhesive layer of the said base material is laminated | stacked should be the surface of the film which consists of a resin material containing the polymer which has the said isocyanate reactive group. Preferred (Invention 7). When the base material has the above-described configuration, an isocyanate-reactive group can be stably present on the surface of the base material on the side where the pressure-sensitive adhesive layer is laminated. Can be more stably reduced.

  In the said invention (invention 7), it is preferable that the polymer which has the said isocyanate reactive group contains 1 type, or 2 or more types chosen from the group which consists of an ethylene- (meth) acrylic acid copolymer and an ionomer (invention). 8). When a base material contains said material, it becomes easy to adjust the mechanical characteristics of a base material, such as breaking elongation.

  In the said invention (invention 5 and 6), the surface by which the said adhesive layer of the said base material is laminated | stacked may be the surface by which surface treatment was given before the said adhesive layer was laminated | stacked. (Invention 9) The surface of the layer containing the material having an isocyanate-reactive group may be used (Invention 10). In these cases, since there are few restrictions required for the material constituting the base material in order to make the isocyanate-reactive group exist, the degree of freedom in designing the base material is high.

  In the above inventions (Inventions 1 to 10), the dicing sheet is JIS, with the exposed surface of the pressure-sensitive adhesive layer opposite to the side facing the substrate as the measurement target surface and the resin sealing surface of the semiconductor package as the adherend surface. Regarding the adhesive strength measured when the 180 ° peeling test is performed in accordance with Z0237: 2009, the ratio of the adhesive strength in the state before energy beam irradiation to the adhesive strength in the state after energy beam irradiation is 3 or more. (Invention 11) When the adhesive strength ratio is in the above range, the possibility of pickup failure in the pickup process can be reduced while reducing the possibility of mold chip scattering in the dicing process or the expanding process.

  In the above inventions (Inventions 1 to 11), the dicing sheet is JIS with the exposed surface opposite the side facing the substrate in the pressure-sensitive adhesive layer as the measurement target surface and the resin sealing surface of the semiconductor package as the adherend surface. It is preferable that the adhesive force measured when the 180 ° peeling test is performed in accordance with Z0237: 2009 is 500 mN / 25 mm or more in a state before irradiation with energy rays (Invention 12). When the adhesive force before energy beam irradiation is in the above range, mold chip scattering is less likely to occur during the dicing process.

  In the said invention (invention 1-12), it is preferable to stick the surface on the opposite side to the said base material of the said adhesive layer on the resin sealing surface of the semiconductor package which resin-sealed the semiconductor chip (invention 13). The dicing sheet according to the above invention has excellent adhesiveness even on a surface having a large surface roughness, and is less likely to cause an adhesive sticking phenomenon. Even if it is used, it is difficult for problems to occur.

  According to the present invention, secondly, the surface on the pressure-sensitive adhesive layer side of the dicing sheet according to any one of the above inventions (1 to 13) is attached to a resin sealing surface of a semiconductor package, and the semiconductor on the dicing sheet is provided. A mold chip manufacturing method is provided in which a package is cut into individual pieces to obtain a plurality of mold chips (Invention 14).

  As described above, the dicing sheet according to any one of the above inventions (1 to 13) has excellent adhesiveness even on a surface having a large surface roughness, and the adhesive sticking phenomenon hardly occurs. In manufacturing a mold chip using a sheet, process defects such as an adhesive sticking phenomenon hardly occur, and defective products based on mold chip scattering hardly occur. Therefore, the quality of the product is hardly deteriorated, and the increase in manufacturing cost due to the defective product is also small.

  According to the present invention, the possibility that the adhesive sticking phenomenon occurs is reduced, and in the dicing process, the expanding process and the pick-up process, the mold chip is scattered and the mold chip is not properly picked up. A dicing sheet is provided that is less likely to occur. Further, by using such a dicing sheet, it is possible to manufacture a mold chip that is excellent in quality and advantageous in terms of cost.

It is a schematic sectional drawing of the dicing sheet which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
1. Dicing Sheet As shown in FIG. 1, a dicing sheet 1 according to an embodiment of the present invention includes a base material 2 and an adhesive layer 3.

(1) Base material The base material 2 included in the dicing sheet 1 according to the present embodiment is not particularly limited as long as the base material 2 is not broken in the expanding process or the pick-up process. The film which consists of material is illustrated. Specific examples of such films include polyethylene films such as low density polyethylene (LDPE) film, linear low density polyethylene (LLDPE) film, and high density polyethylene (HDPE) film, polypropylene film, polybutene film, polybutadiene film, polymethyl. Polyolefin films such as pentene film, ethylene-norbornene copolymer film and norbornene resin film; polyvinyl chloride films such as polyvinyl chloride film and vinyl chloride copolymer film; polyester such as polyethylene terephthalate film and polybutylene terephthalate film Polyurethane film; polyimide film; ionomer resin film; ethylene-vinyl acetate copolymer film, ethylene Ethylene copolymer films such as (meth) acrylic acid copolymer film and ethylene- (meth) acrylic acid ester copolymer film; hydroxyl group-containing resin films such as polyvinyl alcohol film and cellophane; polylactic acid; polystyrene film; polycarbonate film A fluororesin film; and films mainly containing water additives and modified products of these resins. The film constituting the substrate 2 may be a single type, or may be a laminated film in which two or more types are combined. From the viewpoint of easily satisfying requirements such as the elongation at break described later, the substrate 2 is one or two selected from a polyolefin film, an ethylene- (meth) acrylic acid copolymer film, and an ionomer resin film. It is preferable to provide the above. In addition, “(meth) acrylic acid” in the present specification means both acrylic acid and methacrylic acid. The same applies to other similar terms.

  Even if the base material 2 which concerns on this embodiment contains various additives, such as a pigment, a flame retardant, a plasticizer, an antistatic agent, a lubricant, a filler, in the film which uses the said resin material as a main material. Good. Examples of the pigment include titanium dioxide and carbon black. Examples of the filler include organic materials such as melamine resin, inorganic materials such as fumed silica, and metal materials such as nickel particles. The content of such additives is not particularly limited, but should be within a range where the base material 2 exhibits a desired function and does not lose desired smoothness and flexibility.

  In the case where ultraviolet rays are used as energy rays to be irradiated to polymerize the material constituting the pressure-sensitive adhesive layer 3 (that is, the energy ray polymerizable compound (B)), the substrate 2 must be permeable to the ultraviolet rays. Is preferred. In addition, when using an electron beam as an energy beam, it is preferable to have transparency with respect to an electron beam.

  On the surface of the base material 2 on which the pressure-sensitive adhesive layer 3 is laminated (also referred to as “the surface to be treated” in this specification), the reaction with respect to the isocyanate group is performed before the pressure-sensitive adhesive layer 3 is laminated. It is preferable that a functional group having a property (also referred to as “isocyanate-reactive group” in this specification) exists. In this case, the dicing sheet 1 according to this embodiment includes an interface portion between the base material 2 and the pressure-sensitive adhesive layer 3 (in this specification, “interface portion” refers to the interface between the base material and the pressure-sensitive adhesive layer, the base material In the vicinity of the interface and the vicinity of the interface in the pressure-sensitive adhesive layer.) Interaction involving the isocyanate group in the pressure-sensitive adhesive layer 3 and the isocyanate-reactive group of the substrate 2 This interaction increases the adhesion between the substrate 2 and the pressure-sensitive adhesive layer 3 (improved keying). An example of such an interaction is a chemical interaction in which a bond structure formed by a reaction between an isocyanate group and an isocyanate-reactive group is formed. When such a bonded structure is formed, the substrate 2 and the pressure-sensitive adhesive layer 3 are firmly bonded. Therefore, when an isocyanate-reactive group is present on the surface to be treated, peeling at the interface between the base material 2 and the pressure-sensitive adhesive layer 3 is less likely to occur, and the possibility that a pressure-sensitive adhesive sticking phenomenon may occur. Reduced stably.

  The specific type of the isocyanate-reactive group is not particularly limited as long as it can react with the isocyanate group. Examples include a carboxyl group, a hydroxyl group, an amino group, and a thiol group. The isocyanate-reactive group may be composed of one type of functional group or may be composed of a plurality of types of functional groups. The amount of the isocyanate-reactive group present on the surface to be treated of the substrate 2 before the pressure-sensitive adhesive layer 3 is laminated is not particularly limited. When the amount is excessively low, it is difficult to reduce the possibility of the adhesive sticking phenomenon, and when the amount is excessively high, the physical properties of the base material 2 and the physical properties of the adhesive layer 3 are reduced. The dicing sheet may be appropriately set in consideration of the possibility that the dicing sheet is out of the appropriate range (for example, the elongation at break of the base material 2 is excessively reduced). .

  The method for causing the isocyanate-reactive group to exist on the surface to be treated is not particularly limited. For example, the substrate 2 itself includes a film made of a resin material containing a polymer having an isocyanate-reactive group such as a carboxyl group or a hydroxyl group at the main chain, side chain, or terminal, and the surface of the film is a surface to be treated. As a result, an isocyanate-reactive group such as a carboxyl group or a hydroxyl group may be present on the surface to be treated. Compared with the method in which the substrate 2 has such a configuration, the isocyanate-reactive group can be stably present on the surface to be treated, compared to the method in which the isocyanate-reactive group is present on the surface to be treated by surface treatment. The effect which suppresses generation | occurrence | production of the adhesive sticking phenomenon of the dicing sheet 1 which concerns on this embodiment can be acquired especially efficiently. As a film made of a resin material containing a polymer having an isocyanate-reactive group, a film using a resin containing a carboxyl group, such as an ionomer resin film, an ethylene- (meth) acrylic acid copolymer film, or a polylactic acid film And a hydroxyl group-containing resin film. The ionomer resin film is a film using a resin obtained by metal-crosslinking a carboxyl group of a polymer having a carboxyl group. However, since the carboxyl group ion-bonded to a metal ion is usually a part, The group remains. Among these films, the base material 2 is selected from the group consisting of an ionomer resin film and an ethylene- (meth) acrylic acid copolymer film from the viewpoint that it is easy to adjust the elongation at break of the base material as described above. It is preferable to provide one type or two or more types. When an ethylene- (meth) acrylic acid copolymer film is used, the copolymerization ratio of (meth) acrylic acid is 5% by mass based on the total mass of monomers used to form the copolymer. It is preferable to be in the range of about 25% by mass or less.

  Alternatively, for example, the base material 2 is a case where a film of a material having no isocyanate-reactive group is provided as the base material itself, such as a polyolefin-based film, and the corona treatment is performed in advance before the pressure-sensitive adhesive layer 3 is laminated. By subjecting the adherend treated surface to a surface treatment such as the above, an isocyanate-reactive group such as a carboxyl group or a hydroxyl group may be present on the adherend treated surface. Moreover, the to-be-adhered process surface may be formed from the material which has isocyanate reactive groups other than the film which consists of resin-type material containing the polymer which has said isocyanate reactive group. Specifically, the primer layer is provided on the surface of the above-mentioned film on the pressure-sensitive adhesive layer 3 side, the surface to be treated is the surface of this primer layer, and the isocyanate-reactive group is based on the surface of this primer layer. It may be made to exist. In addition, the various coating films may be provided in the surface on the opposite side to the to-be-adhered process surface of the base material 2. FIG.

  The thickness of the base material 2 according to the present embodiment is not limited as long as the dicing sheet 1 can function properly in each of the aforementioned steps. Preferably it is 20-450 micrometers, More preferably, it is 25-200 micrometers, Most preferably, it exists in the range of 50-150 micrometers.

  The elongation at break of the substrate 2 in the present embodiment is preferably 100% or more, particularly preferably 200% or more and 1000% or less, as a value measured at 23 ° C. and a relative humidity of 50%. The base material 2 having a breaking elongation of 100% or more is not easily broken during the expanding process, and the mold chip formed by cutting the semiconductor package is easily separated. The elongation at break is the rate of elongation relative to the original length of the test piece at the time of breaking the test piece in a tensile test based on JIS K7161: 1994 (ISO 527-1: 1993).

  Moreover, it is preferable that the breaking stress measured by the test based on JISK7162: 1994 (ISO527-2: 1993) of the base material 2 in this embodiment is 10 MPa or more, and more preferably 15 MPa or more and 50 MPa or less. Preferably, it is 20 MPa or more and 40 MPa or less. When the breaking stress is less than 10 MPa, when the semiconductor package is bonded to the dicing sheet 1 and then fixed to the ring frame, the base material 2 is soft and may be loosened, which may cause a conveyance error.

(2) Pressure-sensitive adhesive layer The dicing sheet 1 according to the present embodiment includes a pressure-sensitive adhesive layer 3 laminated on one surface of the substrate 2. This pressure-sensitive adhesive layer 3 is formed from a pressure-sensitive adhesive composition containing the components described below.

(2-1) Pressure-sensitive adhesive composition The pressure-sensitive adhesive composition contains a polymer (a1) having a hydroxyl group, an isocyanate-based crosslinking agent (a2), an energy beam polymerizable compound (B), and a tackifier resin (C). If necessary, other components may be contained.

(2-1-1) Polymer having hydroxyl group (a1)
At least a part of the polymer (a1) having a hydroxyl group reacts with a part of the isocyanate-based crosslinking agent (a2) described later to form a crosslinked product (A) of the polymer. Therefore, the pressure-sensitive adhesive layer 3 contains a crosslinked polymer (A).
The weight average molecular weight (Mw) of the polymer (a1) having a hydroxyl group is preferably 10,000 to 2,000,000, and more preferably 100,000 to 1,500,000. The glass transition temperature Tg of the polymer (a1) having a hydroxyl group is preferably in the range of −70 to 30 ° C., more preferably in the range of −60 to 20 ° C. The polymer (a1) having a hydroxyl group may be either a homopolymer obtained by polymerizing one kind of monomer or a copolymer obtained by polymerizing plural kinds of monomers. In any case, the type of monomer for forming the polymer (a1) having a hydroxyl group is not particularly limited. From the viewpoint of easily controlling the physical characteristics and chemical characteristics of the polymer, the polymer (a1) having a hydroxyl group is preferably a copolymer.

  An example of the polymer (a1) having a hydroxyl group is an acrylic polymer having a hydroxyl group. As a monomer (also referred to as “raw material monomer” in the present specification) that can be a raw material for forming such an acrylic polymer having a hydroxyl group, an acrylic monomer having a hydroxyl group (hereinafter referred to as “hydroxyacrylic monomer” in this specification). And non-acrylic monomers having a hydroxyl group, acrylic monomers having no hydroxyl group, and non-acrylic monomers having no hydroxyl group. The acrylic polymer having a hydroxyl group is a structural unit derived from at least one of a hydroxyacrylic monomer and an acrylic monomer having no hydroxyl group so that the polymer becomes an acrylic polymer among the above raw material monomers. And a structural unit derived from at least one of a hydroxyacrylic monomer and a nonacrylic monomer having a hydroxyl group so that the polymer has a hydroxyl group.

  Specific examples of the hydroxyacrylic monomer include (meth) acrylate having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. Specific examples of the non-acrylic monomer having a hydroxyl group include N-methylolacrylamide. From the viewpoint of enhancing the handleability and easy adjustment of the physical properties of the pressure-sensitive adhesive layer 3, the acrylic polymer having a hydroxyl group preferably includes a structural unit derived from a hydroxyacrylic monomer.

  Among the above raw material monomers, specific examples of acrylic monomers having no hydroxyl group include (meth) acrylic acid, itaconic acid, (meth) acrylic acid esters, and derivatives thereof (acrylonitrile, etc.). Specific examples of (meth) acrylic acid esters include chain skeletons such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. (Meth) acrylates having the following: cycloalkyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) ) (Meth) acrylates having a cyclic skeleton such as acrylate, tetrahydrofurfuryl (meth) acrylate, and imide acrylate; water such as glycidyl (meth) acrylate and N-methylaminoethyl (meth) acrylate And (meth) acrylates having a reactive functional group other than groups. When the acrylic monomer having no hydroxyl group is an alkyl (meth) acrylate, the alkyl group preferably has 1 to 18 carbon atoms. Examples of the non-acrylic monomer having no hydroxyl group include olefins such as ethylene and norbornene, vinyl acetate, and styrene.

  The constituent ratio of the raw material monomer for forming the acrylic polymer having a hydroxyl group is not particularly limited. From the viewpoint of stably realizing the properties as an acrylic polymer, the total mass of acrylic monomers, that is, the total of the mass of hydroxyacrylic monomers and the total mass of acrylic monomers having no hydroxyl groups is a hydroxyl group. The ratio of the raw material monomer for forming the acrylic polymer having a ratio to the total mass of the raw material monomer is preferably 30 to 100% by mass, and more preferably 50 to 99% by mass.

(2-1-2) Isocyanate-based crosslinking agent (a2)
The specific kind of isocyanate type crosslinking agent (a2) is not specifically limited, A polyisocyanate compound is illustrated as an example. The polyisocyanate compound is a compound having two or more isocyanate groups per molecule, for example, aromatic polyisocyanate such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate; dicyclohexylmethane-4,4′-diisocyanate, bicycloheptane Alicyclic isocyanate compounds such as triisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and hydrogenated xylylene diisocyanate; acyclic aliphatic isocyanates such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate Can be mentioned.

  Also, biuret bodies, isocyanurate bodies of these compounds, adduct bodies that are reaction products of these compounds with non-aromatic low-molecular active hydrogen-containing compounds such as ethylene glycol, trimethylolpropane, castor oil, etc. The modified product can also be used as a crosslinking agent. The polyisocyanate compound constituting the isocyanate-based crosslinking agent (a2) may be one type or a plurality of types.

  Isocyanate-based crosslinking contained in the above-mentioned pressure-sensitive adhesive composition of the total amount (unit: mol) of isocyanate groups contained in the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 The ratio (referred to as “NCO / OH ratio” in this specification) with respect to the total amount (unit: mol) of hydroxyl groups of the components other than the agent (a2) is 4 or more and 15 or less. In addition, the total amount of the above-mentioned isocyanate groups is based on the NCO content, which is a mass ratio (unit: mass%) of the isocyanate groups contained in the polyisocyanate compound contained in the isocyanate-based crosslinking agent (a2), and the above-mentioned pressure-sensitive adhesive composition. It can obtain | require from the mass of the isocyanate type crosslinking agent (a2) contained. In addition, the total amount of the hydroxyl group is determined by carrying out a neutralization titration method based on JIS K1557-1: 2007 (ISO 14900: 2001), and is an isocyanate-based crosslinking agent contained in the pressure-sensitive adhesive composition. It can be determined from the hydroxyl value of all components other than (a2) (unit: mg KOH / g, also referred to as “crosslinkable hydroxyl value” in the present specification).

  If the NCO / OH ratio is 4 or more, the possibility of the above-mentioned interaction occurring at the interface between the base material 2 and the pressure-sensitive adhesive layer 3 is increased, and the keying is improved, and the possibility of the pressure-sensitive adhesive sticking phenomenon occurring. Reduced. From the viewpoint of more stably reducing the possibility of the adhesive sticking phenomenon, the NCO / OH ratio is preferably 5 or more. On the other hand, when the NCO / OH ratio exceeds 15, the adhesiveness of the pressure-sensitive adhesive layer 3 is lowered, and the possibility of mold chip scattering is increased. From the viewpoint of more stably reducing the possibility of this mold chip scattering, the NCO / OH ratio is preferably 12 or less.

  Content of the isocyanate type crosslinking agent (a2) contained in the adhesive composition for forming the adhesive layer 3 is not specifically limited. When the content is 2 parts by mass or more and 14 parts by mass or less with respect to 100 parts by mass of the polymer (a1) having a hydroxyl group, the NCO / OH ratio can be easily set in the above range (4 to 15). Thus, both the adhesive sticking phenomenon and the mold chip scattering can be prevented more stably. The content is more preferably 4 parts by mass or more and 12 parts by mass or less, and further preferably 6 parts by mass or more and 10 parts by mass or less. In the present specification, “part by mass” indicating the content of each component means an amount as a solid content.

  The crosslinkable hydroxyl value is preferably 2 mgKOH / g or more, more preferably 3 mgKOH / g or more, and particularly preferably 4 mgKOH / g or more. When the crosslinkable hydroxyl value is in this range, it becomes easier to prevent the adhesive sticking phenomenon from occurring by adjusting the NCO / OH ratio to the above range. When the crosslinkable hydroxyl value is excessively low, there is a concern that the amount of NCO groups in the pressure-sensitive adhesive composition becomes too small even if the NCO / OH ratio is in the above range. In this case, the above-mentioned interaction does not sufficiently occur at the interface portion between the base material 2 and the pressure-sensitive adhesive layer 3 in the dicing sheet 1 provided with the pressure-sensitive adhesive layer 3 formed from the pressure-sensitive adhesive composition. It becomes difficult to make the agent residual phenomenon difficult to occur. The upper limit of the crosslinkable hydroxyl value is not particularly limited, but if it is excessively high, the content of the energy beam polymerizable compound (B) described later may be relatively lowered. A problem that the mold chip cannot be picked up easily occurs.

(2-1-3) Energy beam polymerizable compound (B)
The energy ray-polymerizable compound (B) contained in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 provided in the dicing sheet 1 according to the present embodiment has an energy ray-polymerizable group, and includes ultraviolet rays, electron beams, and the like. The specific configuration is not particularly limited as long as the polymerization reaction can be performed by irradiation of the energy beam. When the energy ray polymerizable compound (B) is polymerized, the storage elastic modulus of the pressure-sensitive adhesive layer 3 is increased, and as a result, the pressure-sensitive adhesive property of the pressure-sensitive adhesive layer 3 to the mold chip is lowered and the workability of the pickup process is improved. .

  The kind of energy beam polymerizable group which the energy beam polymerizable compound (B) has is not particularly limited. Specific examples thereof include a functional group having an ethylenically unsaturated bond such as a vinyl group or a (meth) acryloyl group. Among these, a (meth) acryloyl group is more preferable from the viewpoint of high reactivity when irradiated with energy rays.

  The energy ray polymerizable compound (B) is a low molecular weight compound comprising one or more selected from the group consisting of monofunctional monomers and polyfunctional monomers having an energy ray polymerizable group and oligomers of these monomers (this specification) In the book, it is abbreviated as “low molecular weight compound.”) (B1) and energy beam polymerizable polymer (B2) composed of a polymer having an energy beam polymerizable group in the main chain or side chain. it can.

i) Low molecular weight compound (B1)
When the energy beam polymerizable compound (B) contains the low molecular weight compound (B1), the low molecular weight compound (B1) promotes plasticization of the pressure-sensitive adhesive layer 3 in the same manner as the tackifier resin (C) described later. Therefore, it becomes easy to improve the adhesiveness of the pressure-sensitive adhesive layer 3. The molecular weight of the low molecular weight compound (B1) is preferably 100 or more and 30,000 or less as a weight average molecular weight (Mw). When the molecular weight is excessively small, there is a concern about volatilization in the manufacturing process, and at this time, the stability of the composition of the pressure-sensitive adhesive layer 3 is lowered. The molecular weight of the low molecular weight compound (B1) is determined from the weight average molecular weight (Mw) from the viewpoint of more stably reducing the possibility of volatilization during the production process and enhancing the function of plasticizing the pressure-sensitive adhesive layer 3. ) Is preferably 200 or more and 20,000 or less, and more preferably 300 or more and 10,000 or less.

  The specific composition of the low molecular weight compound (B1) is not particularly limited. Specific examples include trimethylolpropane tri (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Alkyl (meth) acrylates having a chain skeleton such as 1,4-butylene glycol di (meth) acrylate and 1,6-hexanediol di (meth) acrylate; dicyclopentadiene dimethoxydi (meth) acrylate, isobornyl (meth) Alkyl (meth) acrylates having a cyclic skeleton such as acrylate; polyethylene glycol di (meth) acrylate, oligoester (meth) acrylate, urethane (meth) acrylate Oligomer, an epoxy-modified (meth) acrylates, polyether (meth) acrylate, and acrylate compounds such as itaconic acid oligomer. Among these, when the polymer (a1) having the above-mentioned hydroxyl group contained in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 is an acrylic polymer, the compatibility with this polymer is high. From the viewpoint of height, an acrylate compound is preferred.

  Content of the low molecular weight compound (B1) in the adhesive layer 3 which concerns on this embodiment is not specifically limited. When the content is excessively small, the amount of the energy beam polymerizable group in the pressure-sensitive adhesive layer 3 is excessively small. There is a concern that the possibility of problems occurring in the pickup process is increased. On the other hand, when the content is excessively large, depending on the type of the low molecular weight compound (B1), there is a concern that compatibility with other components may be reduced. Therefore, the content of the low molecular weight compound (B1) in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 is selected from the viewpoint of reducing the possibility of occurrence of problems in any of the three steps described above. It is preferable to set it as 50 to 150 mass parts with respect to 100 mass parts of unification | combination (a1), and it is more preferable to set it as 75 to 125 mass parts.

ii) Energy beam polymerizable polymer (B2)
The energy beam polymerizable polymer (B2) is a polymer having an energy beam polymerizable group. Although the specific structure of energy beam polymerizable polymer (B2) is not limited, energy beam polymerization type polymer (B2) can have the property of the polymer (a1) which has a hydroxyl group. In this case, the energy beam polymerizable polymer (B2) has a functional group capable of reacting with an isocyanate group such as a hydroxyl group, and reacts with the isocyanate-based crosslinking agent (a2) to form a crosslinked product (A) of the polymer. Thus, when the energy beam polymerizable polymer (B2) has properties as a polymer (a1) having a hydroxyl group, the production process of the pressure-sensitive adhesive layer 3 is simplified, and exists in the pressure-sensitive adhesive layer 3. There are advantages such as easy control of the amount of the energy beam polymerizable group. In this case, the polymer (a1) having a hydroxyl group may not be contained separately. In addition, when the energy beam polymerizable polymer (B2) has properties as a polymer (a1) having a hydroxyl group, “100 parts by mass of the polymer having a hydroxyl group (a1)” has a hydroxyl group. It means 100 parts by mass of the total content of the energy beam polymerizable polymer (B2) having properties as the polymer (a1) and the polymer (a1) having a hydroxyl group.

  The molecular weight of the energy beam polymerizable polymer (B2) is greater than about 30,000 as the weight average molecular weight (Mw). Such an energy ray polymerizable polymer (B2) produces an effect of maintaining the cohesiveness of the pressure-sensitive adhesive layer 3 which is a general function of the pressure-sensitive adhesive main component, similarly to the polymer (a1) having a hydroxyl group. Such an effect is more exhibited as the molecular weight is higher. On the other hand, when the molecular weight of the energy beam polymerizable polymer (B2) is excessively large, there is a high possibility that problems such as difficulty in thinning the pressure-sensitive adhesive layer 3 will occur. Accordingly, the weight average molecular weight (Mw) of the energy beam polymerizable polymer (B2) is preferably about 100,000 to 2,000,000, more preferably about 200,000 to 1,500,000.

  When the energy beam polymerizable polymer (B2) has a structural unit based on (meth) acrylate in the skeleton, it can be prepared, for example, by the following method. An acrylic polymer having a structural unit based on (meth) acrylate and a structural unit based on alkyl (meth) acrylate containing a functional group such as a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, and an epoxy group, and the above-mentioned functional group An energy ray polymerizable group can be added to the acrylic polymer by reacting with a compound having 1 to 5 substituents capable of reacting with a group and energy ray polymerizable groups per molecule. .

  Examples of the energy beam for polymerizing the energy beam polymerizable compound (B) include ionizing radiation, that is, X-rays, ultraviolet rays, and electron beams. Among these, ultraviolet rays that are relatively easy to introduce irradiation equipment are preferable.

When ultraviolet rays are used as the ionizing radiation, near ultraviolet rays including ultraviolet rays having a wavelength of about 200 to 380 nm may be used for ease of handling. What is necessary is just to select suitably according to the kind of energy-beam polymeric compound (B) and the thickness of the adhesive layer 3, and it is about 50-500 mJ / cm < ² > normally, and the amount of ultraviolet rays is 100-450 mJ / cm < ² >. 200 to 400 mJ / cm ² is more preferable. Moreover, ultraviolet illuminance is about 50-500 mW / cm < ² > normally, 100-450 mW / cm < ² > is preferable and 200-400 mW / cm < ² > is more preferable. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a metal halide lamp, a light emitting diode etc. are used.

  When an electron beam is used as the ionizing radiation, the acceleration voltage may be appropriately selected according to the type of the energy beam polymerizable compound (B) and the thickness of the pressure-sensitive adhesive layer 3, and usually an acceleration voltage of 10 to 1000 kV. It is preferable that it is a grade. Moreover, what is necessary is just to set an irradiation dose to the range which an energy-beam polymeric compound (B) hardens | cures appropriately, and is normally selected in the range of 10-1000 krad. The electron beam source is not particularly limited, and for example, various electron beam accelerators such as a Cockloft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type are used. be able to.

(2-1-4) Tackifying resin (C)
The specific kind of tackifying resin (C) contained in the pressure-sensitive adhesive layer 3 according to this embodiment is not limited. Examples of the tackifier resin (C) include rosin-based tackifiers such as rosin and derivatives thereof (specific examples include polymerized rosin, esterified rosin, polymerized rosin ester, disproportionated rosin, and hydrogenated resins thereof). resin; alpha pinene resins, beta-pinene resins, terpene phenol resins, terpene-based tackifying resins and copolymers of terpene and styrene; C ₅ petroleum resins, C ₉ petroleum resins, C 5 _/ C ₉ petroleum resins And petroleum resins such as hydrogenated resins; coumarone resins; alkylphenol resins; xylene resins. By containing a tackifier resin (C) comprising an oligomer having a molecular weight of several hundred to several thousand, the temperature at which the loss tangent determined by the viscoelasticity measurement of the pressure-sensitive adhesive layer 3 usually shows a maximum value is increased. The storage elastic modulus at a higher temperature is lowered, and the tackiness of the pressure-sensitive adhesive layer 3 is increased. From the viewpoint of obtaining the effect of increasing the tackiness more efficiently and suppressing the occurrence of mold chip scattering in the dicing process and the expanding process, among the above tackifying resins, from rosin-based tackifying resins and terpene-based tackifying resins. One kind selected or a mixture of both is preferable as a material constituting the tackifier resin (C).

Content of tackifying resin (C) is suitably set according to the adhesiveness calculated | required by the adhesive layer 3, a storage elastic modulus, etc. As a basic tendency, when the content of the tackifying resin (C) is excessively small, it is difficult to increase the tackiness, and conversely, when the content is excessively large, the adhesive layer 3 is constituted. The compatibility with the other components decreases, the adhesiveness varies, and the storage elastic modulus before energy ray irradiation (also referred to as “storage elastic modulus before irradiation” in this specification) G ′ _p becomes excessively low. Or The tackifier resin (C) in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 from the viewpoint of suppressing variation in the pressure-sensitive adhesive property and facilitating making the pre-irradiation storage elastic modulus G ′ _p within an appropriate range. The content is preferably 15 parts by mass or more and 200 parts by mass or less, more preferably 30 parts by mass or more and 150 parts by mass or less, with respect to 100 parts by mass of the polymer (a1) having a hydroxyl group, and 50 parts by mass. The amount is particularly preferably 100 parts by mass or less.

  When the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 contains a low molecular weight compound (B1) having an energy ray polymerizable group, the compound has the same function as the tackifier resin (C) (pressure-sensitive adhesive). In some cases, the content of the low molecular weight compound (B1) having an energy ray polymerizable group in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 and the tackifier resin (C ) Content is preferably 100 parts by mass or more, more preferably 120 parts by mass or more and 300 parts by mass or less, with respect to 100 parts by mass of the hydroxyl group-containing polymer (a1). More preferably, it is at least 250 parts by mass.

(2-1-5) Other components The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 included in the dicing sheet 1 according to the present embodiment includes a crosslinking accelerator and a photopolymerization initiator in addition to the above components. Further, coloring materials such as dyes and pigments, various additives such as flame retardants and fillers may be contained.

  In forming the pressure-sensitive adhesive layer 3 from the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3, the isocyanate group of the isocyanate-based crosslinking agent (a2) reacts with a functional group having reactivity with respect to the isocyanate group such as a hydroxyl group. Therefore, the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 preferably contains an organic metal compound-based crosslinking accelerator such as an organic tin compound.

  Examples of photopolymerization initiators include photoinitiators such as benzoin compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, thioxanthone compounds, and peroxide compounds, and photosensitizers such as amines and quinones. 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone Examples include 2,4,6-trimethylbenzoyldiphenylphosphine oxide. When ultraviolet rays are used as energy rays, the irradiation time and irradiation amount can be reduced by blending a photopolymerization initiator.

(2-2) Physical properties of pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 3 formed from the pressure-sensitive adhesive composition comprises a polymer (a1) having a hydroxyl group contained in the pressure-sensitive adhesive composition and an isocyanate crosslinking agent. Since (a2) causes a crosslinking reaction, it contains the crosslinked polymer (A) as described above.
Moreover, in the interface part of the base material 2 and the adhesive layer 3, the isocyanate group which this adhesive layer 3 has (this isocyanate group is based on the isocyanate type crosslinking agent (a2) contained in said adhesive composition. ) Is likely to occur, and based on this interaction, the pressure-sensitive adhesive layer 3 formed from the above-described pressure-sensitive adhesive composition is less likely to delaminate between the substrate 2.
Further, the pressure-sensitive adhesive layer 3 has high tackiness before energy beam irradiation based on the tackifier resin (C) contained in the above-mentioned pressure-sensitive adhesive composition, and energy beam irradiation based on the energy beam polymerizable compound (B). Later stickiness is low.
Hereinafter, the physical properties and shape characteristics of the pressure-sensitive adhesive layer 3 will be described in detail. A method for forming the pressure-sensitive adhesive layer 3 from the pressure-sensitive adhesive composition will be described later.

(2-2-1) Storage modulus before irradiation The pressure-sensitive adhesive layer 3 included in the dicing sheet 1 according to the present embodiment preferably has a storage modulus G ′ _p before irradiation of 0.01 MPa or more. When the pre-irradiation storage elastic modulus G ′ _p satisfies this range, the pressure-sensitive adhesive layer 3 becomes excessively soft, and the mold chip may not be scattered during the dicing process, but may cause a problem such as deviation. Can be stably reduced. From the viewpoint of more stably reducing the possibility of the above problem, the storage elastic modulus G ′ _p before irradiation is preferably 0.03 MPa or more. Before irradiation storage modulus G 'maximum _p is not particularly limited, before the storage modulus G irradiation' when the excessively high _p is sticky, become especially sticky before energy ray irradiation is low, resulting in It becomes difficult to satisfy the demand for the adhesive force ratio described below. From the viewpoint of stably realizing the adhesive force ratio within the following range, the storage elastic modulus G ′ _p before irradiation is preferably 0.12 MPa or less, and more preferably 0.09 MPa or less. The pre-irradiation storage elastic modulus can be measured using, for example, a known viscoelasticity measuring device (ARES, manufactured by TA Instruments Inc.). In the measurement, as will be described later in the examples, a layered body having a thickness of about 1 mm made of the material constituting the pressure-sensitive adhesive layer 3 is used as a measurement object from the viewpoint of reducing variation in measurement results. preferable.

(2-2-2) Adhesive strength ratio In this specification, the adhesive strength ratio refers to the exposed surface opposite to the side facing the substrate 2 in the adhesive layer 3 provided in the dicing sheet 1 according to the present embodiment. Dicing sheet 1 measured when a 180 ° peel test is performed in accordance with JIS Z0237: 2009 (ISO 29862-29864: 2007) with the measurement target surface and the resin sealing surface of the semiconductor package as the adherend surface The adhesive strength before irradiation with energy rays (hereinafter also referred to as “pre-irradiation adhesive strength”) and the adhesive strength after irradiation with energy rays (hereinafter referred to as “post-irradiation adhesive strength”). ) Ratio (before / after). It is preferable that the adhesive strength ratio of the dicing sheet 1 according to the present embodiment is 3 or more. When the adhesive force ratio is within such a range, it is possible to reduce the possibility of pick-up failure in the pick-up process while reducing the possibility of mold chip scattering in the dicing process or the expanding process. When the adhesive strength ratio is less than 3, it becomes difficult to keep the adhesive strength before irradiation high, so that it becomes difficult for mold chip scattering to occur or the adhesive strength after irradiation becomes difficult to maintain low. It is easy for pick-up defects to occur. The upper limit of the adhesive force ratio is not particularly set. Since the degree of volume shrinkage that occurs during the polymerization of the pressure-sensitive adhesive layer 3 by irradiation with energy rays is positively correlated with the pressure-sensitive adhesive ratio, when the pressure-sensitive adhesive ratio is excessively high, the mold chip becomes the pressure-sensitive adhesive layer 3. There is a concern that a problem of migrating during this polymerization occurs. Therefore, usually, the adhesive strength ratio is preferably 20 or less, more preferably 13 or less, and particularly preferably 10 or less.

  The preferable ranges of the adhesive strength before irradiation and the adhesive strength after irradiation are the specific conditions of the dicing process, the expanding process and the picking process, the material of the resin sealing surface which is the adherend surface of the semiconductor package as the adherend, It is appropriately set according to the surface state (such as the degree of unevenness). From the viewpoint of making mold chip scattering difficult to occur during the dicing step, usually, the adhesive strength before irradiation is preferably 500 mN / 25 mm or more, and more preferably 1000 mN / 25 mm or more. The post-irradiation adhesive strength is preferably 100 mN / 25 mm or more and 500 mN / 25 mm or less, and more preferably 200 mN / 25 mm or more and 400 mN / 25 mm or less.

(2-2-3) Thickness The thickness of the pressure-sensitive adhesive layer 3 included in the dicing sheet 1 according to the present embodiment is not particularly limited. If it is excessively thin, the adhesiveness tends to vary, and if it is excessively thick, the adhesiveness is excessively increased, making it difficult to control the adhesive force ratio within the above-mentioned range. There is a concern that the possibility of cohesive failure occurring inside the layer 3 is increased. From the viewpoint of stably reducing the possibility of such problems, the thickness of the pressure-sensitive adhesive layer 3 is preferably 2 μm or more and 50 μm or less, more preferably 5 μm or more and 35 μm or less, and 5 μm or more and 20 μm or less. It is particularly preferable to do this.

(3) Release sheet The dicing sheet 1 according to this embodiment is a cover for the pressure-sensitive adhesive layer 3 for the purpose of protecting the pressure-sensitive adhesive layer 3 until the pressure-sensitive adhesive layer 3 is attached to a semiconductor package as an adherend. The release surface of the release sheet may be bonded to the surface opposite to the side facing the adhesive treatment surface. The configuration of the release sheet is arbitrary, and examples include a plastic film coated with a release agent. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based, and the like can be used, and among these, a silicone-based material that is inexpensive and provides stable performance is preferable. Instead of the plastic film of the release sheet, a paper base such as glassine paper, coated paper, and high-quality paper, or a laminated paper obtained by laminating a thermoplastic resin such as polyethylene on a paper base may be used. Although there is no restriction | limiting in particular about the thickness of this peeling sheet, Usually, they are about 20 micrometers or more and 250 micrometers or less.

2. Dicing Sheet Manufacturing Method As an example, the dicing sheet 1 was obtained by applying a coating composition containing a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3 on the surface to be treated of the substrate 2. It can manufacture by drying a coating film.
The composition of the coating composition is not particularly limited as long as it includes the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3. For example, the coating composition contains a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 3, and further contains a solvent from the viewpoint of improving the handling property of the coating process and the leveling property of the coating film. contains. Although the kind of solvent in the case where the composition for coating contains a solvent is not specifically limited, since the adhesive composition for forming the adhesive layer 3 contains an isocyanate type crosslinking agent (a2), a hydroxyl group, amino It is preferable that it consists of an organic substance which does not have a group with high reactivity with respect to isocyanate groups, such as group.
On the adherend treated surface obtained by applying the above coating composition on the adherend treated surface of the substrate 2 with a rod coater, die coater, curtain coater, spray coater, slit coater, knife coater or the like. The pressure-sensitive adhesive layer 3 can be formed by drying the coating film. The properties of the coating composition are not particularly limited as long as it can be applied. The composition for forming the pressure-sensitive adhesive layer 3 may be contained as a solute, or may be contained as a dispersoid. There is also. Moreover, the polymer which has the isocyanate type crosslinking agent (a2) in the adhesive layer 3 and a hydroxyl group by adjusting said drying conditions (temperature, time, etc.) or providing the heat processing for bridge | crosslinking separately. The reaction with (a1) and the isocyanate-reactive group present on the adherend treated surface of the substrate 2 can proceed. In order to make this reaction sufficiently proceed, after the pressure-sensitive adhesive layer 3 is laminated on the base material 2 by the above-described method or the like, the obtained dicing sheet 1 is placed in an environment of 23 ° C. and 50% relative humidity, for example. Curing may be performed such as standing for days.

  Alternatively, the coating composition is applied onto the release surface of the release sheet to form a coating film, which is dried to form a laminate composed of the pressure-sensitive adhesive layer 3 and the release sheet. A surface of the pressure-sensitive adhesive layer 3 opposite to the side facing the release sheet may be attached to the surface to be treated of the substrate 2 to obtain a laminate of the dicing sheet 1 and the release sheet. The release sheet in this laminate may be peeled off as a process material, or may protect the pressure-sensitive adhesive layer 3 until being attached to the semiconductor package.

3. Next, a method of manufacturing a mold chip from a semiconductor package using the dicing sheet 1 according to the present embodiment will be described.
In use, the dicing sheet 1 according to the present embodiment has a surface on the side of the pressure-sensitive adhesive layer 3 (when a release sheet is affixed to the surface, the release sheet is peeled off to reveal it). Affixed to the resin sealing surface of the semiconductor package. The outer peripheral portion of the dicing sheet 1 is usually attached to an annular jig called a ring frame for conveyance and fixation to the apparatus by an adhesive layer 3 provided in the portion. Since the pressure-sensitive adhesive layer 3 contains a tackifier resin (C) or the like, the adhesive strength before irradiation of the dicing sheet 1 is enhanced. Therefore, even if the semiconductor package affixed to the dicing sheet 1 is subjected to a dicing process, the possibility that mold chips formed by dividing the semiconductor package into pieces will be reduced during processing. The semiconductor package is an electronic component assembly in which semiconductor chips are mounted on each base of the base assembly as described above, and these semiconductor chips are collectively sealed with resin. It has a sealing surface, and its thickness is about 200 to 2000 μm. The resin sealing surface has a rough arithmetic average roughness Ra of about 0.5 to 10 μm, and the sealing material contains a mold release component to facilitate removal from the mold of the sealing device. For this reason, even if the pressure-sensitive adhesive layer of the dicing sheet is attached to the resin sealing surface, sufficient fixing performance tends not to be exhibited. In addition, the size of the mold chip formed by the dicing process is usually 10 mm × 10 mm or less, and in recent years it may be 5 mm × 5 mm or less, and further about 1 mm × 1 mm, but the dicing sheet 1 according to the present embodiment. In a preferred embodiment, since the adhesive strength before irradiation is sufficiently high, it can sufficiently cope with such fine pitch dicing.

  After the dicing process is completed, an expanding process for extending the dicing sheet 1 in the main surface direction is usually performed so that a plurality of mold chips arranged close to each other on the dicing sheet 1 can be easily picked up. The degree of extension may be set as appropriate in consideration of the distance between adjacent mold chips and the tensile strength of the base material 2.

  When the adjacently disposed mold chips are appropriately separated by performing the expanding process, the mold chips on the pressure-sensitive adhesive layer 3 are picked up by a general-purpose means such as a suction collet. If the energy beam irradiation is performed from the substrate 2 side of the dicing sheet 1 according to the present embodiment before the implementation of this pickup process, the pressure-sensitive adhesive layer 3 included in the dicing sheet 1 becomes the energy beam polymerizable compound contained therein. The polymerization reaction of (B) proceeds and the adhesive strength after irradiation decreases. According to a preferred embodiment, the post-irradiation adhesive strength is 1/3 or less of the pre-irradiation adhesive strength, and the possibility of inconvenience of being unable to pick up in the pickup process is reduced. The implementation time of this energy beam irradiation will not be specifically limited if it is after the completion of the dicing operation in the dicing process and before the start of the pickup process. From the viewpoint of reducing the possibility of mold chip scattering in the expanding process, it is preferable to carry out after the expanding process. However, since the pressure-sensitive adhesive layer 3 is cured by energy ray irradiation, the layer shrinks slightly. When misalignment due to shrinkage becomes a problem, energy beam irradiation may be performed before the expanding step.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
(1) Preparation of coating composition A coating composition having the following composition was prepared.
i) As a polymer (a1) having a hydroxyl group, a copolymer obtained by copolymerizing 100 parts by mass of butyl acrylate, 2 parts by mass of acrylic acid and 0.5 parts by mass of 2-hydroxyethyl acrylate (weight) 100 parts by mass with an average molecular weight of 600,000 and a solid content concentration of 40% by mass)
ii) As the energy ray polymerizable compound (B), an acrylate compound comprising a hexafunctional urethane acrylate oligomer (14-29B manufactured by Dainichi Seika Kogyo Co., Ltd., weight average molecular weight 2000, solid content concentration 80% by mass) as a solid content is 100. Parts by mass,
iii) 62.5 parts by mass of terpene phenol-based tackifier resin (Polystar U115 manufactured by Yashara Chemical Co., Ltd., solid content concentration: 100% by mass) as the solid content as the tackifier resin (C),
iv) Polyisocyanate compound (trimethylolpropane adduct of tolylene diisocyanate, Nippon Polyurethane Coronate L, 3 isocyanate groups in one molecule, solid content concentration of 75% by mass as isocyanate-based crosslinking agent (a2) 9.4 parts by mass with an NCO content of 26% by mass described below as a solid content, and v) Irgacure 184 (manufactured by Ciba Specialty Chemicals, Inc., solid content concentration of 100% by mass) as a photopolymerization initiator. As 7.5 parts by mass.

(2) Production of a dicing sheet A release sheet (SP-PET382120 manufactured by Lintec Corporation) in which a silicone release agent layer having a thickness of 0.1 μm is formed on one main surface of a base film made of polyethylene terephthalate having a thickness of 38 μm. , Width length 1000 mm). On the release surface of this release sheet, the aforementioned coating composition was applied with a rod coater so that the finally obtained pressure-sensitive adhesive layer had a thickness of 10 μm. The obtained coating film is allowed to stand in an oven at 80 ° C. for 1 minute together with the release sheet to dry the coating film and advance the reaction between the polymer (a1) having a hydroxyl group and the isocyanate crosslinking agent (a2). Thus, a laminate composed of a release sheet and an adhesive layer (thickness: 10 μm) was obtained.
140-μm thick ethylene-methacrylic acid copolymer (EMAA) film (the copolymerization ratio of methacrylic acid is 9% by mass based on the total mass of the monomers used, the breaking elongation is 26 MPa, and the breaking stress is 1 side of the base material made of the above-mentioned base material was treated as an adhesion-treated surface, and the surface on the pressure-sensitive adhesive layer side of the laminate was affixed to that surface, and the base as shown in FIG. A dicing sheet comprising a material and a pressure-sensitive adhesive layer was obtained in a state where a release sheet was further laminated on the surface on the pressure-sensitive adhesive layer side.

[Example 2]
In Example 1, the dicing sheet was obtained by performing the same operation as in Example 1 except that the content of the tackifier resin (C) contained in the coating composition was changed to 25 parts by mass as the solid content. It was.

Example 3
In Example 1, except that the type of tackifier resin (C) contained in the coating composition was changed to petroleum resin (FTR 6100 manufactured by Mitsui Chemicals, solid content concentration 100% by mass), and Example 1 The same operation was performed to obtain a dicing sheet.

Example 4
In Example 1, except that the type of tackifier resin (C) contained in the coating composition was changed to a rosin ester-based tackifier resin (KE-311 manufactured by Arakawa Chemical Industries, Ltd., solid content concentration: 100% by mass). Performed the same operation as Example 1, and obtained the dicing sheet.

Example 5
In Example 1, the same operation as in Example 1 was performed except that the content of the isocyanate-based crosslinking agent (a2) contained in the coating composition was changed to 13.2 parts by mass as a solid content, and dicing was performed. A sheet was obtained.

Example 6
In Example 1, the same operation as in Example 1 was performed except that the content of the isocyanate-based crosslinking agent (a2) contained in the coating composition was changed to 6.6 parts by mass as a solid content, and dicing was performed. A sheet was obtained.

Example 7
A dicing sheet was obtained in the same manner as in Example 1 except that the base material was changed to a polyethylene film having a thickness of 140 μm (breaking elongation: 28 MPa, breaking stress: 580%).

Example 8
The same operation as in Example 1 was performed except that the base material was changed to an ionomer film (breaking elongation: 24 MPa, breaking stress: 530%) having a thickness of 140 μm and a central metal of Zn ion in Example 1. A dicing sheet was obtained.

[Comparative Example 1]
In Example 1, except that the content of the isocyanate-based crosslinking agent (a2) contained in the coating composition was changed to 1 part by mass as a solid content, the same operation as in Example 1 was performed, and a dicing sheet was obtained. Obtained.

[Comparative Example 2]
In Example 1, a dicing sheet was obtained by performing the same operation as in Example 1 except that the energy ray polymerizable compound (B) was not contained in the coating composition.

[Comparative Example 3]
In Example 1, the same operation as in Example 1 was performed except that the content of the isocyanate-based crosslinking agent (a2) contained in the coating composition was changed to 27.2 parts by mass as a solid content, and dicing was performed. A sheet was obtained.

  Table 1 shows the compositions of the coating compositions according to Examples and Comparative Examples.

[Test Example 1] <Measurement of NCO / OH ratio>
(1) Crosslinkable hydroxyl value Test liquid having a composition obtained by not containing the isocyanate-based crosslinking agent (a2) from the respective compositions of the coating compositions according to Examples 1 to 9 and Comparative Examples 1 and 2 Specifically, a test solution for measuring a crosslinkable hydroxyl value comprising a polymer (a1) having a hydroxyl group, an energy beam polymerizable compound (B), a tackifier resin (C), a photopolymerization initiator, and a solvent is prepared. did. In the test liquid according to Comparative Example 2, the energy beam polymerizable compound (B) was not contained.
Using this crosslinkable hydroxyl value measurement test solution as a solution to be measured, the neutralization titration method is carried out according to JIS K1557-1: 2007, and the crosslinkable hydroxyl value (unit: mgKOH / g) of each test solution is measured. did. The measurement results are shown in Table 2.

(2) NCO content rate 5-10 g of the isocyanate-based crosslinking agent (a2) was sampled and the mass of the solid content was measured (unit: mg). This was dissolved in 20 ml of toluene, and 2N was obtained in the resulting solution. 20 ml of a toluene solution of n-dibutylamine was added and allowed to stand at room temperature for 15 minutes to react the polyisocyanate compound contained in the isocyanate crosslinking agent (a2) with n-dibutylamine.
After completion of the reaction, using an automatic titrator (APB-410 manufactured by Kyoto Electronics Co., Ltd.), the total amount of the obtained reaction mixture was back titrated with 1N hydrochloric acid to neutralize unreacted n-dibutylamine in the reaction mixture. The volume of 1N hydrochloric acid required (sample titration, unit: ml) was determined.
On the other hand, the same operation as described above was performed except that the isocyanate-based crosslinking agent (a2) was not included, and the volume of 1N hydrochloric acid required for neutralization of unreacted n-dibutylamine was similarly determined (blank titer, unit: ml). Asked.
From the sample titration and blank titration determined as described above, the NCO content was determined according to the following formula. As is clear from the following formula, the NCO content is the mass ratio (unit: mass%) of isocyanate groups contained in the polyisocyanate compound contained in the isocyanate-based crosslinking agent (a2).
NCO content = (blank titration−sample titration) × 42 / sample mass × 100

(3) NCO / OH ratio The number of moles M _OH (unit: mol) of the crosslinkable hydroxyl group per 100 g of the test solution for crosslinkable hydroxyl group measurement corresponding to each of the examples and comparative examples was determined by the following formula.
M _OH = crosslinkable hydroxyl value / 1000 / KOH formula amount (56.1) × 100
On the other hand, for each of the coating compositions according to Examples and Comparative Examples, in the coating composition when the total mass of components capable of providing a crosslinkable hydroxyl group in the coating composition is 100 g The mass W (unit: g) of the isocyanate-based crosslinking agent was determined, and the number of moles of isocyanate groups M _NCO (unit: mol) of the isocyanate crosslinking agent of the mass W was calculated by the following formula.
M _NCO = NCO content / 100 / total atomic weight of isocyanate group constituent atoms (42) × W
From the number of moles M _OH and M _NCO determined by the above formula, the NCO / OH ratio for each of the coating compositions according to Examples and Comparative Examples was determined by the following formula.
NCO / OH ratio = M _NCO / M _OH
Table 2 shows the crosslinkable hydroxyl value and the NCO / OH ratio.

[Test Example 2] <Keying test>
The dicing sheets produced according to Examples 1 to 9 and Comparative Examples 1 and 2 were cured by standing for 7 days in an environment of 23 ° C. and a relative humidity of 50%. A square keying test sheet was obtained. A grid cut of 21 lines (number of squares: 400) was made in both the vertical and horizontal directions at 5 mm intervals in the center of the main surface of the keying test sheet on the pressure-sensitive adhesive layer side. The cut of each line was made so that the depth of cut into the base material was shallow although the pressure-sensitive adhesive layer was completely cut. 5 rows of cellophane adhesive tapes (Cello Tape (registered trademark) No. 405 manufactured by Nichiban Co., Ltd.) were pasted on the main surface of the keying test sheet thus obtained on the adhesive layer side so that the tapes overlap each other. The cell board was covered with a cellophane adhesive tape to which the entire grid cuts were attached. In this state, it was left for 20 minutes in an environment of 23 ° C. and 50% relative humidity. After that, while holding the keying test sheet with one hand, hold the other end of the cellophane adhesive tape on the other side, and peel the cellophane adhesive tape all at once along the normal direction of the main surface of the keying test sheet. .
Observe the grid notch portion of the keying test sheet after peeling the cellophane adhesive tape, and measure the number of squares that have not been partially peeled off as the number of attached masses. The non-peeling rate (unit: %). When the non-peeling rate was 80% or more, it was determined to be acceptable. The results are shown in Table 2.
Non-peeling rate = number of adhered mass / 400 × 100

[Test Example 3] <Measurement of adhesive strength ratio>
The dicing sheets produced according to the above-mentioned examples and comparative examples were cured by standing for 7 days in an environment of 23 ° C. and a relative humidity of 50%, and then each was cut and adhesive having a length of 200 mm and a width of 25 mm A force measurement sheet was obtained. Using a resin for semiconductor packages (KE-G1250 manufactured by Kyocera Chemical Co., Ltd.), a sheet-like member having a thickness of 600 μm and an arithmetic average roughness Ra of one main surface of 2 μm was manufactured. For each of the above-mentioned adhesive force measurement sheets, a laminate comprising the sheet-like member and the adhesive force measurement sheet is obtained by sticking the surface on the adhesive layer side to the one main surface of the sheet-like member. Obtained. The obtained laminate was left in an atmosphere of 23 ° C. and 50% relative humidity for 20 minutes. About the laminate after standing, using a universal tensile tester (Orientec Co., Ltd., TENSILON / UTM-4-100), in accordance with JIS Z0237: 2009, 180 ° peeling test (for measuring adhesive force) And the adhesive strength before irradiation was measured (unit: mN / 25 mm).

Another set of laminates composed of the sheet-like member and the adhesive force measurement sheet was prepared and left for 20 minutes in an atmosphere of 23 ° C. and 50% relative humidity. Thereafter, using a UV irradiation device (RAD-2000m / 12, manufactured by Lintec Co., Ltd.), UV irradiation (illuminance 230 mW / cm ² , light amount 190 mJ / cm ² ) was performed from the dicing sheet side in a nitrogen atmosphere, and the laminate described above The energy beam polymerizable compound (B) contained in the pressure-sensitive adhesive layer was polymerized. About the laminated body after this ultraviolet irradiation, the peeling test on the same conditions as the peeling test for measuring said adhesive force before irradiation was performed, and the adhesive force after irradiation was measured (unit: mN / 25mm).
From the thus obtained pre-irradiation adhesive strength and post-irradiation adhesive strength, the adhesive strength ratio was determined. The obtained pre-irradiation adhesive strength and adhesive strength ratio are shown in Table 2.

[Test Example 4] <Measurement of chip scattering rate in dicing process>
A glass epoxy plate (glass fiber impregnated with epoxy resin and cured) is used instead of a semiconductor substrate, and a semiconductor package resin (manufactured by Kyocera Chemical: KE-G1250) is transfer molded under the following conditions. Then, a sealing resin having a size of 50 mm × 50 mm and a thickness of 600 μm was formed to obtain a member simulating a semiconductor package (hereinafter referred to as “test member”).
<Transfer molding conditions>
Sealing device: made by Apic Yamada, MPC-06M Trial Press
Injection resin temperature: 180 ° C
Resin injection pressure: 6.9 MPa
Resin injection time: 120 seconds The arithmetic average roughness Ra of the surface of the obtained test member on the sealing resin side was 2 μm.

After performing curing by leaving the test member on the surface of the sealing resin side in a dicing sheet prepared in Examples and Comparative Examples for 7 days in an environment of 23 ° C. and 50% relative humidity, respectively. Attached using a tape mounter (manufactured by Lintec Corporation: Adwill RAD2500), the periphery of the test member side surface in the laminate of the obtained test member and dicing sheet (the surface on the adhesive layer side of the dicing sheet is exposed) The dicing ring frame (manufactured by Disco Corporation: 2-6-1) was adhered to the portion). Next, the test member was diced under the following conditions to obtain a chip-like member (number: 100) simulating a 5 mm square mold chip.
<Dicing conditions>
・ Dicing machine: DFD-651 made by DISCO
・ Blade: ZBT-5074 (Z111OLS3) manufactured by DISCO
・ Blade thickness: 0.17 mm
-Blade tip length: 3.3 mm
・ Blade rotation speed: 30000 rpm
・ Cutting speed: 100 mm / min ・ Base material cutting depth: 50 μm
・ Cutting water volume: 1.0 L / min ・ Cutting water temperature: 20 ° C.
The member obtained by the dicing process, the chip-like member attached to the surface of the dicing sheet on the pressure-sensitive adhesive layer side is visually observed, and the number of chip-like members scattered from the dicing sheet during the dicing process is counted. The number was divided by the number of divisions 100 in the dicing step to obtain the chip scattering rate (unit:%). The results are shown in Table 1.
A chip-like member imitating a 1 mm square device chip by dicing the test member under the same conditions as in Test Example 3 except that the dicing pitch was changed from 5 mm to 1 mm and the cutting speed was changed to 50 mm / min. 2500). The chip scattering rate (unit:%) in this case was also obtained. The results are shown in Table 2.

[Test Example 5] <Pickup test>
By producing the test member and dicing process under the same conditions as in Test Example 3, a chip having a size of 1 mm × 1 mm on the surface on the pressure-sensitive adhesive layer side of each dicing sheet produced in Examples and Comparative Examples A member with a sticky member was obtained.

A dicing sheet in a member in which a chip-like member is attached to the surface of the dicing sheet on the pressure-sensitive adhesive layer side is measured at a speed of 300 mm / min using an expanding device (ME-300B type manufactured by JCM Co., Ltd.). An expanding step of extending 20 mm in the in-plane direction was performed.
Using the ultraviolet irradiation device (RAD-2000m / 12 manufactured by Lintec Co., Ltd.) for the above-mentioned member after the expanding process, ultraviolet irradiation (illuminance 230 mW / cm ² , light amount 190 mJ / cm ² ) from the dicing sheet side in a nitrogen atmosphere. ) To polymerize the energy ray polymerizable compound (B) contained in the pressure-sensitive adhesive layer included in the dicing sheet.

  Subsequently, a pick-up test was performed on 100 chip-like members located near the center of the main surface of the dicing sheet. That is, a device in which a needle (No. 5) is set on a digital push-pull gauge (MODEL-RE manufactured by Aiko Engineering Co., Ltd.) is used as an apparatus, and a portion in contact with a chip-like member to be picked up in a dicing sheet is The tip was pushed 1.5 mm with a needle, a vacuum collet was attached to the surface of the protruding tip-like member opposite to the side facing the dicing sheet, and the tip-like member attached to the vacuum collet was lifted. At this time, the number of chip-shaped members picked up by the vacuum collet is measured, and the number is divided by the test number (100) to obtain the pickup rate (unit:%). When the pickup rate is 80% or more It was determined to be good (“A” in Table 1), and when less than 80%, it was determined to be defective (“F” in Table 1). The results are shown in Table 2.

  As can be seen from Table 1, the dicing sheet of the example satisfying the conditions of the present invention can be said to be less likely to cause defects in any of the dicing process, the expanding process, and the pickup process.

  The dicing sheet according to the present invention is suitably used as a dicing sheet for a semiconductor package in which the unevenness of the resin sealing surface that is the adherend surface is large.

DESCRIPTION OF SYMBOLS 1 ... Dicing sheet 2 ... Base material 3 ... Adhesive layer

Claims (14)

A dicing sheet comprising a base material and an adhesive layer laminated on at least one surface of the base material,
The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a hydroxyl group-containing polymer (a1), an isocyanate-based crosslinking agent (a2), an energy beam polymerizable compound (B), and a tackifier resin (C). Because
Components other than the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition in the total amount (unit: mol) of isocyanate groups contained in the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition A dicing sheet having an NCO / OH ratio of 4 or more and 15 or less relative to the total amount (unit: mol) of hydroxyl groups possessed by.   The content of the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition is 2 parts by mass or more and 14 parts by mass or less with respect to 100 parts by mass of the polymer (a1) having a hydroxyl group. The dicing sheet according to 1.   The dicing sheet according to claim 1 or 2, wherein the hydroxyl value of all components other than the isocyanate-based crosslinking agent (a2) contained in the pressure-sensitive adhesive composition is 2 mgKOH / g or more.   The dicing sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer has a thickness of 5 µm to 35 µm.   5. The isocyanate-reactive group according to claim 1, wherein an isocyanate-reactive group is present on the surface of the substrate on which the pressure-sensitive adhesive layer is laminated before the pressure-sensitive adhesive layer is laminated. Dicing sheet.   The dicing sheet according to claim 5, wherein the isocyanate-reactive group includes one or more selected from the group consisting of a carboxyl group, a hydroxyl group, an amino group, and a thiol group.   The dicing sheet according to claim 5 or 6, wherein the surface of the substrate on which the pressure-sensitive adhesive layer is laminated is a surface of a film made of a resin material containing a polymer having the isocyanate-reactive group.   The dicing sheet according to claim 7, wherein the polymer having an isocyanate-reactive group includes one or more selected from the group consisting of an ethylene- (meth) acrylic acid copolymer and an ionomer.   The dicing sheet according to claim 5 or 6, wherein the surface of the substrate on which the pressure-sensitive adhesive layer is laminated is a surface that has been subjected to surface treatment before the pressure-sensitive adhesive layer is laminated.   The dicing sheet according to claim 5 or 6, wherein a surface of the substrate on which the pressure-sensitive adhesive layer is laminated is a surface of a layer containing a material having the isocyanate-reactive group.   The dicing sheet is pulled 180 ° in accordance with JIS Z0237: 2009, with the exposed surface of the adhesive layer opposite to the side facing the substrate as the measurement target surface and the resin sealing surface of the semiconductor package as the adherend surface. 11. The ratio of the adhesive strength in the state before energy beam irradiation to the adhesive strength in the state after energy beam irradiation is 3 or more with respect to the adhesive strength measured when the peeling test is performed. The dicing sheet described in 1.   The dicing sheet is pulled 180 ° in accordance with JIS Z0237: 2009, with the exposed surface of the adhesive layer opposite to the side facing the substrate as the measurement target surface and the resin sealing surface of the semiconductor package as the adherend surface. The dicing sheet according to any one of claims 1 to 11, wherein an adhesive force measured when the peeling test is performed is 500 mN / 25 mm or more in a state before irradiation with energy rays.   The dicing sheet according to any one of claims 1 to 12, wherein a surface of the pressure-sensitive adhesive layer opposite to the base material is attached to a resin sealing surface of a semiconductor package in which a semiconductor chip is resin-sealed.   The surface on the pressure-sensitive adhesive layer side of the dicing sheet according to any one of claims 1 to 13 is affixed to a resin sealing surface of a semiconductor package, and the semiconductor package on the dicing sheet is cut and separated. A method for producing a mold chip, which is singulated to obtain a plurality of mold chips.

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