Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
  • C09J133/04—Homopolymers or copolymers of esters
  • C09J133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C09J133/062—Copolymers with monomers not covered by C09J133/06
  • C09J133/066—Copolymers with monomers not covered by C09J133/06 containing -OH groups
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/24—Plastics; Metallised plastics based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/24—Plastics; Metallised plastics based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/241—Polyolefin, e.g.rubber
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
  • C09J7/38—Pressure-sensitive adhesives [PSA]
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P54/00—Cutting or separating of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/7402—Wafer tapes, e.g. grinding or dicing support tapes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/7412—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support the auxiliary support including means facilitating the separation of a device or wafer from the auxiliary support
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P72/00—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof
  • H10P72/70—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping
  • H10P72/74—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support
  • H10P72/7416—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support used during dicing or grinding
  • H10P72/742—Handling or holding of wafers, substrates or devices during manufacture or treatment thereof for supporting or gripping using temporarily an auxiliary support used during dicing or grinding involving stretching of the auxiliary support post dicing
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P95/00—Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
  • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2301/00—Additional features of adhesives in the form of films or foils
  • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
  • C09J2301/416—Additional features of adhesives in the form of films or foils characterized by the presence of essential components use of irradiation

Definitions

• the present invention relates to an adhesive tape for electronic components. More specifically, the present invention relates to an adhesive tape for electronic components that can be used to fix wafers in the dicing process in which wafers such as semiconductor wafers and glass wafers are divided into chip-shaped elements.
• Electronic components such as chip-type electronic components, including integrated circuits (ICs), resistors, capacitors, coils, and IR cut filters, are generally manufactured by attaching a sticky and elastic adhesive tape for electronic components to a wafer, such as a semiconductor wafer or glass wafer, followed by a dicing process in which the wafer is divided into chips, an expanding process in which the processing tape is expanded, and a pick-up process in which the divided chips are picked up.
• a sticky and elastic adhesive tape for electronic components to a wafer, such as a semiconductor wafer or glass wafer, followed by a dicing process in which the wafer is divided into chips, an expanding process in which the processing tape is expanded, and a pick-up process in which the divided chips are picked up.
• Patent Document 1 discloses a stealth dicing method for a wafer, which includes a process of forming a modified region inside the wafer by multiphoton absorption and designating this modified region as the section to be cut by irradiating laser light onto the inside of a semiconductor substrate to which an adhesive tape for electronic components is attached, with an adhesive layer (die-bond resin layer) interposed therebetween, and a process of cutting the wafer and adhesive layer along the section to be cut by expanding the adhesive tape for electronic components.
• the wafer cutting method described in Patent Document 1 mentioned above the wafer is cut without contact by irradiating it with laser light and expanding adhesive tape for electronic components, so the physical load on the wafer is small and it is possible to cut the wafer without generating cutting chips, as occurs with the currently mainstream blade dicing.
• the adhesive layer is cut by expansion, no cutting chips from the adhesive layer are generated. For this reason, it has attracted attention as an excellent technology that can replace blade dicing.
• the division technology described in the above-mentioned document is mainly intended for semiconductor wafers, but it can also be applied to glass wafers by changing the laser engine of the equipment to one for glass.
• the stealth dicing method uses adhesive tape for electronic components that is used in conventional dicing processes using blades.
• the stress (expansion force) during expansion is absorbed by the adhesive tape for electronic components, and the expansion force is not sufficiently transmitted to the modified area inside the wafer, making it difficult to chip the wafer with a good yield.
• a stealth dicing adhesive sheet that is made up of a substrate and an adhesive layer formed on one side thereof, in which the adhesive sheet has a Young's modulus of 200 to 600 MPa at 23°C, and the adhesive layer has a storage modulus of 0.10 to 50 MPa at 23°C (see Patent Document 2).
• a dicing tape in which, after radiation exposure or heat treatment, the tensile load at a tape elongation rate of 10% under test conditions of a width of 25 mm, a gauge length and grip length of 100 mm, and a tensile speed of 300 mm/min is 30 N or more, and the surface roughness Ra of the back surface of the base film of the expanding dicing tape is 0.3 ⁇ m or more (see Patent Document 3).
• the adhesive layer when used on wafers with complex, stepped adherend shapes, the adhesive layer needs to be thick so that it can conform to the steps. However, if the adhesive layer is made thick, the stress is relieved when it is expanded, reducing the ability to separate the wafer. This makes it difficult to achieve both the ability of the adhesive tape for electronic components to conform to the steps on the wafer surface and the ability to separate the wafer.
• the present invention aims to provide an adhesive tape for electronic components that can be bonded to thick, hard wafers with steps on the surface with sufficient conformity, and that can be expanded to effectively divide the wafer into chips.
• the adhesive tape for electronic components is an adhesive tape for electronic components having an adhesive layer formed on at least one surface of a base film, the adhesive layer being a radiation-curable adhesive layer that is cured by irradiation with radiation, the total thickness of the base film and the adhesive layer being 170 ⁇ m or less, and being characterized in that, in a tensile test in accordance with JIS K7161-2:2014 in the TD direction of a laminate of the base film and the adhesive layer after irradiation with radiation, the following formula (1) is satisfied, where A is the load at a strain of 20% and B is the load at a strain of 40%: B[N]-A[N]>0[N]...(1)
• the above-mentioned adhesive tape for electronic components preferably has a load A of 10 N or more at a strain of 20% and a load B of 10 N or more at a strain of 40%.
• the adhesive layer of the above-mentioned adhesive tape for electronic components preferably has a thickness of 5 to 100 ⁇ m.
• the adhesive tape for electronic components preferably has a base film made of a polyolefin resin.
• the above-mentioned adhesive tape for electronic components is preferably used for dicing wafers, which includes a laser processing step in which a portion of a wafer having a step on its surface to be divided is irradiated with laser light to form a modified region inside the wafer that will become the starting point of fracture, a tape application step in which an adhesive layer is attached to the wafer, a radiation irradiation step in which the adhesive layer is irradiated with radiation, and a singulation step in which the wafer is expanded after the radiation irradiation step to divide the wafer into individual pieces along the division lines.
• even thick and hard wafers with steps on the surface can be bonded with sufficient conformity to the adhesive tape for electronic components, and the adhesive tape for electronic components can be expanded to effectively divide the wafer into chips.
• 1 is a cross-sectional view illustrating a schematic structure of an adhesive tape for electronic components according to an embodiment of the present invention.
• 1A to 1C are cross-sectional views illustrating a laser processing step in a wafer singulation method using an adhesive tape for electronic components according to an embodiment of the present invention.
• 1A to 1C are cross-sectional views illustrating a tape application step in a wafer singulation method using an adhesive tape for electronic components according to an embodiment of the present invention.
• 1A to 1C are cross-sectional views illustrating a schematic diagram of a singulation step in a wafer singulation method using an adhesive tape for electronic components according to an embodiment of the present invention.
• 1A to 1C are cross-sectional views that diagrammatically show a process of maintaining an expanded state after the wafer is singulated using the adhesive tape for electronic components according to an embodiment of the present invention.
• the adhesive tape 1 for electronic components is formed by applying at least one type of adhesive to at least one side of the base film 2 to form an adhesive layer 3.
• the adhesive tape 1 for electronic components may further include a release film 4 on the adhesive layer 3 to protect the adhesive layer 3.
• the adhesive tape 1 for electronic components may be a long laminate of the base film 2, the adhesive layer 3, and the release film 4 wound in a roll, or cut into sheets at predetermined lengths.
• only the base film 2 and the adhesive layer 3 may be punched out in advance into a predetermined label shape (so-called precut processing) as in conventional dicing tapes.
• precut processing a predetermined label shape
• the material of the base film 2 is not particularly limited as long as it is easy to stretch during the expanding process of the pressure-sensitive adhesive tape 1 for electronic components, does not break, and transmits the stress caused by the expanding process to the adhesive layer 3 sufficiently to adequately divide the wafer 6 (see FIG. 2). It is preferable for the base film 2 to have uniform and isotropic expandability, since this allows the wafer to be cut evenly in all directions during the expanding process. From these viewpoints, it is preferable for the base film 2 to be selected from polyolefins, polyvinyl chloride, and urethane elastomers.
• the above polyolefins include homopolymers or copolymers of ⁇ -olefins such as polyethylene, polypropylene, ethylene-propylene copolymers, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-acrylic acid copolymers, ionomers, or mixtures of these.
• ⁇ -olefins such as polyethylene, polypropylene, ethylene-propylene copolymers, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-acrylic acid copolymers, ionomers, or mixtures of these.
• ionomer resins which are synthetic resins that utilize the cohesive force of metal ions to form polymer aggregates
• ionomer resins which are synthetic resins that utilize the cohesive force of metal ions to form polymer aggregates
• ionomer resins in which ethylene-(meth)acrylic acid binary copolymers or ethylene-(meth)acrylic acid-(meth)acrylic acid alkyl ester terpolymers are crosslinked with metal ions.
• metal ions contained in the ionomer resins, but examples include zinc ions and sodium ions. Zinc ions are preferred in terms of low elution and low contamination.
• crosslinked resins selected from low density polyethylene having a specific gravity of 0.910 or more and less than 0.930, very low density polyethylene having a specific gravity of less than 0.910, and ethylene-vinyl acetate copolymers are also suitable.
• a method of crosslinking a method of irradiating the resin with energy rays such as electron beams can be mentioned.
• Such a thermoplastic crosslinked resin has a certain degree of uniform extensibility because crosslinked and non-crosslinked sites coexist in the resin.
• thermoplastic crosslinked resin contains almost no chlorine atoms in the molecular chain structure, so that even if the tape that is no longer needed after use is incinerated, it does not generate chlorinated aromatic hydrocarbons such as dioxins and their analogues, and the environmental load is small.
• non-crosslinked resin is a mixed resin of polypropylene and a styrene-based copolymer.
• a propylene homopolymer or copolymer for example, a block type or random type propylene-ethylene copolymer
• a random type propylene-ethylene copolymer has low rigidity and is preferable. If the content of the ethylene structural unit in the propylene-ethylene copolymer is 0.1 mass% or more, it is preferable in that the rigidity of the base film 2 is low and the compatibility between the resins in the mixed resin is high. If the rigidity of the base film 2 is appropriate, the severability of the wafer 6 (see FIG. 2) is improved, and if the compatibility between the resins is high, the extrusion discharge amount is likely to be stabilized.
• the content of the ethylene structural unit in the propylene-ethylene copolymer is 7 mass% or less, it is preferable in that the polymerization reaction for obtaining the propylene-ethylene copolymer can be stably performed. It is more preferable that the content is 5 mass% or less.
• the styrene copolymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound.
• aromatic vinyl compound include styrene, t-butylstyrene, ⁇ -methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethylstyrene, vinyltoluene, and p-tert-butylstyrene.
• the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, and 2,3-dimethyl-1,3-butadiene.
• the styrene-based polymer may be hydrogenated, and a styrene-hydrogenated isoprene-styrene copolymer is preferred.
• a styrene-hydrogenated isoprene-styrene copolymer is preferred.
• the styrene-based copolymer When the styrene-based copolymer is hydrogenated, it has good compatibility with polypropylene and can prevent embrittlement and discoloration due to oxidative deterioration caused by double bonds in the main chain.
• the content of the styrene structural unit in the styrene copolymer is 5% by mass or more, it is preferable in that the styrene copolymer is easily polymerized stably when prepared. If it is 40% by mass or less, it is flexible and has high extensibility.
• styrene copolymer either a block copolymer or a random copolymer can be used.
• a random copolymer is preferred because the styrene structural units are uniformly dispersed, the rigidity can be prevented from becoming too large, and the extensibility of the base film 2 is improved.
• the polypropylene content in the mixed resin of polypropylene and styrene copolymer is preferably 30% by mass or more, since it is possible to suppress unevenness in the thickness of the base film 2. If the thickness of the base film 2 is uniform, the expandability is easily isotropic. More preferably, it is 50% by mass or more. Furthermore, if the polypropylene content is 90% by mass or less, the rigidity of the base film 2 can be appropriately set. If the rigidity of the base film 2 is too high, the force required to expand the base film 2 becomes large, so the load on the device increases, and it may not be possible to expand sufficiently to separate the wafer 6 (see Figure 2).
• the lower limit of the content of the styrene copolymer in the mixed resin is preferably 10% by mass or more, and it is easy to adjust the rigidity of the base film 2 to be suitable for the device.
• the upper limit is preferably 70% by mass or less, since it is possible to suppress unevenness in thickness, and more preferably 50% by mass or less.
• the base film 2 In order to cure the adhesive layer 3 (described below) by irradiating it with radiation and thereby reduce its adhesive strength, it is preferable that the base film 2 has the above characteristics and is also radiation-transmitting.
• the base film 2 is a single layer, but is not limited to this and may be multiple layers.
• the multiple layers may be multiple layers formed by laminating two or more types of layers made of resin, or multiple layers formed by laminating layers made of one type of resin. If the two or more types of resins are crosslinked resins or non-crosslinked resins, it is preferable from the viewpoint that the properties of each are enhanced and expressed, and if a crosslinked resin and a non-crosslinked resin are combined and laminated, it is preferable from the viewpoint that the shortcomings of each are compensated for.
• the multi-layer base film 2 can be manufactured by a conventional extrusion method, lamination method, or the like. When using a lamination method, an adhesive may be interposed between the layers. A conventional adhesive can be used as the adhesive.
• the thickness of the base film 2 is preferably 60 to 150 ⁇ m. If the thickness of the base film 2 is too thin, the base film 2 may break, or the tensile strength may be insufficient and the expand-and-cut may not be possible. If the thickness of the base film 2 is too thick, the amount of deformation relative to the amount of stretching during the expand-and-cut may be insufficient, and the distance between the elements of the wafer 6 (see FIG. 2) may become too short, making it impossible to apply the subsequent pick-up process. Furthermore, the base film 2 may be difficult to deform during pick-up, which may deteriorate the pick-up properties and cause pick-up failure or chip breakage. The thickness of the base film 2 is more preferably 80 to 120 ⁇ m.
• the adhesive layer 3 is not particularly limited as long as it has the properties of not peeling off from the wafer during the dicing process, of having retention properties sufficient to prevent defects such as chip floating, of transmitting stress due to expansion to the wafer, and of being capable of being peeled off from the wafer during tape transfer.
• the main polymer component that makes up the adhesive can be appropriately selected from various types of polymers such as (meth)acrylic resin, epoxy resin, natural rubber resin, and synthetic rubber resin, but among these, (meth)acrylic resin is preferable.
• (Meth)acrylic resin allows easy control of adhesive strength.
• the base polymer constituting the adhesive layer 3 preferably has a glass transition temperature of -65°C to -30°C.
• the glass transition temperature refers to the glass transition temperature measured by DSC (differential scanning calorimeter) at a heating rate of 0.1°C/min. If the glass transition temperature exceeds -30°C, the adhesion to the adherend tends to improve, and there is a risk of adhesive residue remaining on the electronic component when the electronic component is peeled off. If the glass transition temperature is less than -65°C, the adhesive becomes very sticky, which has a negative effect on handling during work, and is therefore undesirable.
• the base polymer constituting the adhesive preferably has a weight-average molecular weight Mw of 700,000 or more. If the weight-average molecular weight Mw of the base polymer is less than 700,000, low molecular weight components will bleed out onto the surface of the adhesive layer 3, contaminating the adherend. In addition, when the electronic component is peeled off, there is a risk of adhesive residue remaining on the electronic component.
• the adhesive layer 3 is a radiation-curable type that is cured by exposure to radiation.
• the adhesive composition constituting the radiation-curable adhesive layer 3 can be a combination of a polymer constituting the adhesive and a radiation-polymerizable compound, or a polymer constituting the adhesive that incorporates a functional group (preferably an ethylenically unsaturated group) that polymerizes with radiation.
• the adhesive contains a photopolymerization initiator to promote polymerization by radiation.
• the adhesive contains a crosslinking agent.
• the resin used in the adhesive layer 3 is not particularly limited, and known adhesive resins such as chlorinated polypropylene resin, acrylic resin, polyester resin, polyurethane resin, and epoxy resin can be used, but an acrylic adhesive with an acrylic polymer as the base polymer is preferred.
• acrylic polymers include acrylic polymers using one or more of (meth)acrylic acid alkyl esters (e.g., 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, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester, octadecyl ester, eicosyl ester, and other linear or branched alkyl esters having an alkyl
• the acrylic polymer may contain units corresponding to other monomer components copolymerizable with the (meth)acrylic acid alkyl ester or cycloalkyl ester, if necessary, for the purpose of modifying the cohesive strength, heat resistance, etc.
• 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; acid anhydride monomers such as maleic anhydride and itaconic anhydride; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and 10-hydroxydecyl (meth)acrylate.
• copolymerizable monomers examples include hydroxyl group-containing monomers such as 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, etc.; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid, etc.; phosphoric acid group-containing monomers such as 2-hydroxyethylacryloylphosphate, etc.; acrylamide, acrylonitrile, etc.
• These copolymerizable monomer components can be used alone or in combination. The amount of these copolymerizable monomers used is preferably 40% by weight or less of the total monomer components.
• polyfunctional monomers and the like can also be included as copolymerization monomer components as necessary.
• polyfunctional monomers include hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and urethane (meth)acrylate.
• the amount of polyfunctional monomer used is preferably 30% by weight or less of the total monomer components in terms of adhesive properties, etc.
• Acrylic polymers can be prepared, for example, by applying a suitable method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization to a mixture of one or more component monomers.
• various methods can be adopted, such as a method of crosslinking using an appropriate external crosslinking agent such as a polyfunctional isocyanate compound, a polyfunctional epoxy compound, a melamine compound, a metal salt compound, a metal chelate compound, an amino resin compound, or a peroxide, or a method of mixing a low molecular weight compound having two or more carbon-carbon double bonds and crosslinking by irradiating radiation, etc.
• an external crosslinking agent is used, the amount used is determined appropriately depending on the balance with the base polymer to be crosslinked and further depending on the use as an adhesive.
• the base polymer In general, it is preferable to mix about 20 parts by weight or less, and more preferably 0.1 to 20 parts by weight, per 100 parts by weight of the base polymer.
• various additives such as tackifiers and anti-aging agents may be used in the adhesive as necessary from the viewpoint of preventing deterioration, etc.
• An example of a radiation-curable adhesive is an additive-type radiation-curable adhesive in which a radiation-curable monomer component or a radiation-curable oligomer component is added to the adhesive described above.
• radiation-curable monomer components to be blended include urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,4-butanediol di(meth)acrylate, etc.
• These monomer components can be used alone or in combination of two or more.
• the radiation-curable oligomer component may be a variety of oligomers, such as urethane-based, polyether-based, polyester-based, polycarbonate-based, and polybutadiene-based oligomers, and those with a molecular weight in the range of about 100 to 30,000 are suitable.
• the amount of radiation-curable monomer component or oligomer component to be blended can be appropriately determined according to the type of adhesive layer 3, so as to reduce the adhesive strength of the adhesive layer 3. In general, the amount is, for example, 5 to 500 parts by weight, and preferably 70 to 150 parts by weight, per 100 parts by weight of the base polymer, such as an acrylic polymer, that constitutes the adhesive.
• examples of radiation curable adhesives include endogenous type radiation curable adhesives that use a base polymer in which radiation curable groups have been introduced into the polymer side chain, main chain, or main chain end.
• Endogenous type radiation curable adhesives do not need to contain low molecular weight components such as oligomer components, or do not contain large amounts of them, so they are preferred because they can form adhesive layer 3 with a stable layer structure without the oligomer components moving within the adhesive over time.
• the base polymer into which the radiation-curable group has been introduced can be any polymer that has a carbon-carbon double bond and is adhesive, without any particular restrictions.
• a base polymer one that has an acrylic polymer as the basic skeleton is preferable.
• the basic skeleton of an acrylic polymer include the acrylic polymers listed above.
• one method is to first copolymerize a monomer having a functional group into the acrylic polymer, and then to carry out a condensation or addition reaction with a compound having a functional group and a carbon-carbon double bond that can react with this functional group while maintaining the radiation curability of the carbon-carbon double bond.
• combinations of these functional groups include a carboxylic acid group and an epoxy group, a carboxylic acid group and an aziridyl group, and a hydroxyl group and an isocyanate group.
• a combination of a hydroxyl group and an isocyanate group is preferred because of the ease of reaction tracking.
• the functional group may be on either the acrylic polymer or the compound, but the preferred combination is that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group.
• examples of isocyanate compounds having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, and m-isopropenyl- ⁇ , ⁇ -dimethylbenzyl isocyanate.
• the acrylic polymer may be a copolymer of the hydroxyl group-containing monomers listed above, or ether compounds such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.
• Intrinsic radiation-curable adhesives can use the base polymer having the carbon-carbon double bond (particularly acrylic polymer) alone, but can also contain photopolymerizable compounds such as the radiation-curable monomer components and oligomer components to the extent that the properties are not adversely affected.
• the amount of the photopolymerizable compound is usually 30 parts by weight or less per 100 parts by weight of the base polymer, and preferably 0 to 10 parts by weight.
• the radiation-curable adhesive is to be cured by ultraviolet light, etc., it is preferable that it contains a photopolymerization initiator.
• a (meth)acrylic acid ester copolymer comprising an acrylic acid ester represented by CH 2 ⁇ CHCOOR (wherein R is an alkyl group having 4 to 18 carbon atoms), a hydroxyl group-containing monomer, and an isocyanate compound having a radical reactive carbon-carbon double bond in the molecule is particularly preferred.
• the amount of carbon-carbon double bonds is preferably 0.5 meq/g or more and 1.8 meq/g or less. If the amount of carbon-carbon double bonds is less than 0.5 meq/g, when a chip-shaped electronic component is peeled off from the adhesive tape for electronic components 1, there is a risk that a residue of the adhesive from the adhesive tape for electronic components 1 will adhere to the surface of the electronic component, resulting in so-called adhesive residue.
• the amount of double bonds can be quantitatively measured by the weight increase method using a bromine addition reaction in a dark place in a vacuum, in which the amount of carbon-carbon double bonds contained in approximately 10 g of adhesive that has been heated and dried.
• the (meth)acrylic acid ester copolymer may contain units corresponding to other monomer components as necessary.
• double bond-containing isocyanate compounds examples include methacryloyl isocyanate, acryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, 2-acryloyloxyethyl isocyanate, m-isopropenyl- ⁇ , ⁇ -dimethylbenzyl isocyanate, etc. Double bond-containing isocyanate compounds can be used alone or in combination of two or more.
• an external crosslinking agent can be used appropriately in the radiation curing adhesive to adjust the adhesive strength before and after radiation exposure.
• Specific means for the external crosslinking method include a method of adding and reacting a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, or a melamine-based crosslinking agent.
• a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, or a melamine-based crosslinking agent.
• the amount used is determined appropriately depending on the balance with the base polymer to be crosslinked, and further depending on the intended use as an adhesive.
• the amount of the external crosslinking agent used is generally 20 parts by weight or less (preferably 0.1 to 10 parts by weight) per 100 parts by weight of the base polymer.
• the radiation curing adhesive may contain various additives such as tackifiers, antiaging agents, and foaming agents that are conventionally known.
• the adhesive layer 3 can be formed by applying the adhesive composition as described above onto the base film 2 and drying it.
• the thickness of the adhesive layer 3 is preferably 5 to 100 ⁇ m, more preferably 20 ⁇ m or more, even more preferably 30 ⁇ m or more, and also preferably more than 50 ⁇ m. It is also preferably 70 ⁇ m or less. If the thickness of the adhesive layer 3 is thin, when the shape of the adherend is complicated and there is a step on the adherend surface, the adhesive layer 3 does not follow the step of the wafer, and air is caught near the step. Conversely, if the adhesive layer 3 is too thick, the response of the push-up pin when picking up the chip may be poor, and the pick-up performance may be reduced. In addition, if the tape is too thick, there is a risk of it coming off the jig, so the total thickness of the base film 2 and the adhesive layer 3 is 170 ⁇ m or less.
• the adhesive layer 3 may be configured with multiple layers laminated together. When multiple layers are present, it is preferable to use the above-mentioned radiation-curable adhesive for the layer to which the electronic components are attached, but heat-foaming adhesives can also be used for the other layers. Radiation-curable adhesives are cured by ultraviolet light or electron beams, etc., and are easy to peel off, while heat-foaming adhesives are made easy to peel by the use of a foaming agent or expansion agent. In addition, an intermediate layer such as a primer layer may be provided between the base film 2 and the adhesive layer 3, if necessary.
• a release film 4 which is usually used as a separator, may be attached to the side of the adhesive layer 3 to protect the adhesive layer 3 until it is put into practical use.
• materials that can be used for the release film 4 include synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate, and paper.
• the surface of the synthetic resin film may be subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, if necessary, to improve releasability from the adhesive layer 3.
• the thickness of the release film 4 is usually 10 to 100 ⁇ m, and preferably about 25 to 50 ⁇ m.
• the pressure-sensitive adhesive tape 1 for electronic components satisfies the following formula (1) when the load at a strain of 20% is A and the load at a strain of 40% is B.
• the TD (Transverse Direction) direction is a direction perpendicular to the MD (Machine Direction) direction, which is the flow direction of the base film 2 during production, and perpendicular to the unwinding direction of the base film 2, and refers to the width direction of the base film 2.
• the tensile test is performed in accordance with JIS K 7161-2:2014 using a 1B-type test piece cut out from a laminate of the base film 2 and the adhesive layer 3 after radiation exposure so that the laminate is stretched in the TD direction, using a tensile tester at 23°C and 50% RH with a chuck distance of 50 mm and a tensile speed of 300 mm/min.
• the tensile load in the TD direction of the laminate of the base film 2 and the adhesive layer 3 continues to increase up to a strain of 40% by irradiating radiation to harden the adhesive layer 3, so that it is possible to prevent the base film 2 from yielding in the TD direction.
• the adhesive layer 3 is hardened by irradiating radiation, stress relaxation is suppressed even if the adhesive layer 3 is made thick. As a result, even if the adhesive layer 3 is made thick for use with a wafer having steps on the adhesion surface, for example, by expanding the adhesive tape for electronic components 1 after irradiating radiation to harden the adhesive layer 3, it can be easily cut into chips.
• the adhesive tape 1 for electronic components preferably has a load A of 10 N or more at a strain of 20% and a load B of 10 N or more at a strain of 40%.
• the load at which the laminate of the base film 2 and the adhesive layer 3 is strained by 20% in the TD direction after irradiation is smaller than the load at which the laminate of the base film 2 and the adhesive layer 3 is strained by 20% in the TD direction before irradiation.
• the pressure-sensitive adhesive tape 1 for electronic components of the present invention is used in a method for producing electronic components, which includes a singulation step of singulating the wafer 6 (see FIG. 2) along a dividing line starting from a modified region 7 (see FIG. 2) formed inside the wafer 6 (see FIG. 2) by expanding the wafer 6 after irradiating the pressure-sensitive adhesive layer 3 with radiation. Therefore, other steps and the order of steps are not particularly limited.
• the pressure-sensitive adhesive tape 1 for electronic components can be suitably used in the following methods for producing electronic components (A) and (B).
• Manufacturing method for electronic components (A) (a) a laser processing step of irradiating a laser beam 5 to a portion of a wafer to be divided, and forming a modified region 7 inside the wafer 6 by multiphoton absorption; (b) a tape application step of applying the adhesive layer 3 of the adhesive tape 1 for electronic components to the rear surface of the wafer 6; (c) a radiation exposure step of irradiating the pressure-sensitive adhesive layer 3 with radiation; (d) a singulation step of dividing the wafer 6 along the dividing lines by expanding the adhesive tape 1 for electronic components to obtain a plurality of chips 9; (e) picking up the chip 9 from the adhesive layer 3 of the adhesive tape 1 for electronic components; A method for manufacturing an electronic component comprising the steps of:
• Manufacturing method for electronic components (B) (a) a tape application step of applying an adhesive layer 3 of an adhesive tape 1 for electronic components to a rear surface of a wafer; (b) irradiating a laser beam 5 onto a portion of the wafer to be divided, thereby forming a modified region 7 inside the wafer 6 by multiphoton absorption; (c) a radiation exposure step of irradiating the pressure-sensitive adhesive layer 3 with radiation; (d) a singulation step of dividing the wafer 6 along the dividing lines by expanding the adhesive tape 1 for electronic components to obtain a plurality of chips 9; (e) picking up the chip 9 from the adhesive layer 3 of the adhesive tape 1 for electronic components; A method for manufacturing an electronic component comprising the steps of:
• a laser beam 5 is irradiated onto the portion of the wafer 6 to be divided, forming a modified region 7 inside the wafer 6 through multiphoton absorption.
• the adhesive layer 3 of the adhesive tape 1 for electronic components is bonded to the back surface of the wafer 6, and a ring frame 11 is bonded to the outer periphery of the adhesive layer 3.
• radiation is irradiated onto the adhesive layer 3 from the side of the base film 2 of the adhesive tape 1 for electronic components, causing the adhesive layer 3 to harden.
• the adhesive tape 1 for electronic components to which the wafer 6 with the modified region 7 is attached, is placed on the stage 10 with the base film 2 side facing down.
• the stage 10 of the expanding device is raised to expand the adhesive tape 1 for electronic components.
• the expansion conditions are an expansion speed of, for example, 0.1 to 20 mm/sec, and an expansion amount (push-up amount) of, for example, 1 to 70 mm.
• a fixing jig 8 such as a grip ring manufactured by Technovision Co., Ltd. is attached to maintain the tape in an expanded state.
• a transfer tape is attached and the chip is transferred to recover the chip after cutting.
• the chip 9 may be pushed up from the base film 2 side by a push-up pin and picked up by a suction collet.
• the adhesive tape for electronic components according to the present invention includes the following aspects:
• An adhesive tape for electronic components comprising a base film and a pressure-sensitive adhesive layer formed on at least one surface thereof, the pressure-sensitive adhesive layer being a radiation-curable pressure-sensitive adhesive layer that is cured by irradiation with radiation, the total thickness of the base film and the pressure-sensitive adhesive layer being 170 ⁇ m or less, and the pressure-sensitive adhesive tape for electronic components satisfying the following formula (1) in a tensile test in accordance with JIS K7161-2:2014 in the TD direction of a laminate of the base film and the pressure-sensitive adhesive layer after irradiation with radiation, where A is the load at a strain of 20% and B is the load at a strain of 40%: B[N]-A[N]>0[N]...(1)
• An adhesive tape for electronic components according to any one of [1] to [4], used for dicing a wafer including a laser processing step in which a portion of a wafer having a step on its surface to be divided is irradiated with laser light to form a modified region inside the wafer that will become the starting point of the fracture, a tape attachment step in which an adhesive layer is attached to the wafer, a radiation irradiation step in which the adhesive layer is irradiated with radiation, and a singulation step in which, after the radiation irradiation step, the wafer is expanded to singulate the wafer along the division lines.
• Substrate film A A film having a total thickness of 80 ⁇ m was prepared by extrusion molding, in which 8 ⁇ m of ethylene-methacrylic acid copolymer Nucrel AN4214C (trade name, Mitsui-Dow Polychemical Co., Ltd.), 64 ⁇ m of ethylene-methacrylic acid-(2-methyl-propyl acrylate) terpolymer-Zn ++ ionomer resin Himilan 1855 (trade name, manufactured by Mitsui-Dow Polychemical Co., Ltd.) and 8 ⁇ m of Nucrel AN4214C were laminated. This was used as substrate film A.
• Nucrel AN4214C trade name, Mitsui-Dow Polychemical Co., Ltd.
• Substrate film B A film having a total thickness of 130 ⁇ m was prepared by extrusion molding, in which 13 ⁇ m of Nucrel AN4214C (trade name, Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid copolymer, 104 ⁇ m of Himilan 1855 (trade name, manufactured by Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid-(2-methyl-propyl acrylate) terpolymer-Zn ++ ionomer resin, and 13 ⁇ m of Nucrel AN4214C were laminated. This film was used as substrate film B.
• Nucrel AN4214C trade name, Mitsui-Dow Polychemical Co., Ltd.
• Substrate film C A film having a total thickness of 150 ⁇ m was prepared by extrusion molding, in which 15 ⁇ m of Nucrel AN4214C (trade name, Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid copolymer, 120 ⁇ m of Himilan 1855 (trade name, manufactured by Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid-(2-methyl-propyl acrylate) terpolymer-Zn ++ ionomer resin, and 15 ⁇ m of Nucrel AN4214C were laminated. This film was used as substrate film C.
• Nucrel AN4214C trade name, Mitsui-Dow Polychemical Co., Ltd.
• Substrate film D A film having a total thickness of 80 ⁇ m was prepared by extrusion molding, in which 8 ⁇ m of Nucrel AN4214C (trade name, Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid copolymer, 64 ⁇ m of Himilan AM7316 (trade name, manufactured by Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid-(2-methyl-propyl acrylate) terpolymer-Zn ++ ionomer resin, and 8 ⁇ m of Nucrel AN4214C were laminated. This film was used as substrate film D.
• Nucrel AN4214C trade name, Mitsui-Dow Polychemical Co., Ltd.
• Substrate film E A film having a total thickness of 100 ⁇ m was prepared by extrusion molding, in which 10 ⁇ m of Nucrel AN4214C (trade name, Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid copolymer, 80 ⁇ m of Himilan 1855 (trade name, manufactured by Mitsui-Dow Polychemical Co., Ltd.), which is an ethylene-methacrylic acid-(2-methyl-propyl acrylate) terpolymer-Zn ++ ionomer resin, and 10 ⁇ m of Nucrel AN4214C were laminated. This film was used as substrate film E.
• Nucrel AN4214C trade name, Mitsui-Dow Polychemical Co., Ltd.
• Polymer A An acrylic copolymer (glass transition temperature: ⁇ 64° C.) having as constituent units 78% by weight of 2-ethylhexyl acrylate, 21% by weight of 2-hydroxyethyl acrylate, and 1% by weight of methacrylic acid was added with 2-methacryloyloxyethyl isocyanate so that the amount of double bonds became 0.59 (meq/g).
• Polymer B An acrylic copolymer (glass transition temperature: -64°C) having structural units of 78% by weight of 2-ethylhexyl acrylate, 21% by weight of 2-hydroxyethyl acrylate, and 1% by weight of methacrylic acid was synthesized.
• Polymer C An acrylic copolymer (glass transition temperature: ⁇ 64° C.) having as constituent units 78% by weight of 2-ethylhexyl acrylate, 21% by weight of 2-hydroxyethyl acrylate, and 1% by weight of methacrylic acid was added with 2-methacryloyloxyethyl isocyanate so that the amount of double bonds was 0.30 (meq/g).
• Polymer D 2-methacryloyloxyethyl isocyanate was added to an acrylic copolymer (glass transition temperature: ⁇ 64° C.) having as constituent units 78% by weight of 2-ethylhexyl acrylate, 21% by weight of 2-hydroxyethyl acrylate, and 1% by weight of methacrylic acid so that the amount of double bonds was 0.90 (meq/g).
• Coronate L isocyanate-based hardener, product name, manufactured by Tosoh Corporation
• Adhesive composition A 5% by weight of a photopolymerization initiator (Irgacure 184 (trade name), manufactured by Ciba-Geigy Japan Ltd.) and 5% by weight of an isocyanate-based curing agent (Coronate L (trade name), manufactured by Tosoh Corporation) were mixed with respect to the weight of polymer A to obtain adhesive composition A.
• a photopolymerization initiator Irgacure 184 (trade name), manufactured by Ciba-Geigy Japan Ltd.
• an isocyanate-based curing agent Coronate L (trade name), manufactured by Tosoh Corporation
• Adhesive composition B was obtained by mixing 5% by weight of a photopolymerization initiator (Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Co., Ltd.) and 5% by weight of an isocyanate-based curing agent (Coronate L (product name), manufactured by Tosoh Corporation) relative to the weight of polymer B.
• a photopolymerization initiator Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Co., Ltd.
• an isocyanate-based curing agent Coronate L (product name), manufactured by Tosoh Corporation
• Adhesive composition C was obtained by mixing 5% by weight of a photopolymerization initiator (Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Ltd.) and 5% by weight of an isocyanate-based curing agent (Coronate L (product name), manufactured by Tosoh Corporation) relative to the weight of polymer C.
• a photopolymerization initiator Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Ltd.
• an isocyanate-based curing agent Coronate L (product name), manufactured by Tosoh Corporation
• Adhesive composition D was obtained by mixing 5% by weight of a photopolymerization initiator (Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Co., Ltd.) and 5% by weight of an isocyanate-based curing agent (Coronate L (product name), manufactured by Tosoh Corporation) relative to the weight of polymer D.
• a photopolymerization initiator Irgacure 184 (product name), manufactured by Nippon Ciba-Geigy Co., Ltd.
• an isocyanate-based curing agent Coronate L (product name), manufactured by Tosoh Corporation
• Example 1 The pressure-sensitive adhesive composition A was applied to the surface of the base film A so that the film thickness after drying would be 30 ⁇ m, and then dried to prepare the pressure-sensitive adhesive tape for electronic components according to Example 1.
• Example 2 The pressure-sensitive adhesive composition A was applied to the surface of the base film A so that the film thickness after drying would be 60 ⁇ m, and then dried to prepare a pressure-sensitive adhesive tape for electronic components according to Example 2.
• Example 3 The pressure-sensitive adhesive composition A was applied to the surface of the base film B so that the film thickness after drying would be 30 ⁇ m, and then dried to prepare a pressure-sensitive adhesive tape for electronic components according to Example 3.
• Example 4 The pressure-sensitive adhesive composition A was applied to the surface of the substrate film D so that the film thickness after drying would be 15 ⁇ m, and then dried to prepare a pressure-sensitive adhesive tape for electronic components according to Example 4.
• Example 5 The pressure-sensitive adhesive composition B was coated on the surface of the base film E so that the film thickness after drying would be 10 ⁇ m, and then dried. After that, while peeling off the release separator, the pressure-sensitive adhesive composition A was coated on the surface of the base film E so that the film thickness after drying would be 30 ⁇ m, and then dried, thereby producing an adhesive tape for electronic components according to Example 5.
• Example 6 The pressure-sensitive adhesive composition B was coated on the surface of the base film E so that the film thickness after drying would be 20 ⁇ m, and then dried. After that, while peeling off the release separator, the pressure-sensitive adhesive composition A was coated on the surface of the base film E so that the film thickness after drying would be 30 ⁇ m, and then dried, thereby producing an adhesive tape for electronic components according to Example 6.
• Example 7 The pressure-sensitive adhesive composition C was applied to the surface of a base film E so that the film thickness after drying would be 20 ⁇ m, and then dried. After that, while peeling off the release separator, the pressure-sensitive adhesive composition A was applied to the surface of the base film E so that the film thickness after drying would be 30 ⁇ m, and then dried to produce an adhesive tape for electronic components according to Example 7.
• Example 8 The pressure-sensitive adhesive composition D was applied to the surface of the substrate film E so that the film thickness after drying would be 15 ⁇ m, and then dried to prepare a pressure-sensitive adhesive tape for electronic components according to Example 8.
• Example 9 The pressure-sensitive adhesive composition A was applied to the surface of the base film A so that the film thickness after drying would be 90 ⁇ m, and then dried to prepare a pressure-sensitive adhesive tape for electronic components according to Example 9.
• step (a) the adhesive tape for electronic components according to the examples and comparative examples was laminated to the semiconductor wafer at a lamination pressure of 0.3 MPa and 5 mm/sec using a lamination machine DR3000II (product name, manufactured by Nitto Seiki Co., Ltd.) manufactured by Lintec Corporation.
• the glass wafer was laminated to an optical filter with a mask having a height of 10 ⁇ m (manufactured by Tanaka Giken Co., Ltd.).
• the glass wafer was laminated to the adhesive tape for electronic components so that the dividing lines of the glass wafer were aligned with the MD and TD directions of the base film.
• step (d) the stage of an expanding device OEX-800III manufactured by Omiya Kogyo Co., Ltd. was raised to expand the adhesive tape for electronic components, and the outer periphery of the adhesive tape for electronic components was clamped by a grip ring consisting of an inner ring and an outer ring.
• the expansion amount was adjusted as the conditions for step (d) to an expansion speed of 1 mm/sec and an expansion height of 20 mm.
• the expansion amount refers to the amount of change in the relative position between the grip ring and the stage before and after the stage was raised.
• the chip size was set to 4 x 4 mm square.
• step (b) After carrying out step (b), the conformability was evaluated by the following method. With the adhesive tape for electronic components attached, the diameter of the air that had entered was observed from the side opposite to the side where the tape was attached using a laser microscope. Products with no air at all were evaluated as good products with a rating of ⁇ , products with an air diameter of less than 100 ⁇ m were evaluated as acceptable products with a rating of ⁇ , and products with an air diameter of 100 ⁇ m or more were evaluated as defective products with a rating of ⁇ .
• step (d) After the above step (d) was performed, it was confirmed whether the glass wafer was divided into chips.
• the glass wafer in which the entirety was divided along the intended dividing line was evaluated as a good product with a rating of ⁇ , and the glass wafer in which a part or the entirety was not divided along the intended dividing line was evaluated as a defective product with a rating of ⁇ .
• the adhesive tape for electronic components came off the grip ring during the implementation of step (d), so the evaluation of the divisibility was not performed.
• the adhesive tapes for electronic components according to the examples in a tensile test in the TD direction of a laminate of a base film and an adhesive layer after irradiation according to JIS K7161-2:2014, where A is the load at 20% strain and B is the load at 40% strain, B[N]-A[N]>0[N], and because the total thickness of the base film and the adhesive layer is 170 ⁇ m or less, the adhesive tapes for electronic components according to the examples achieved good results in the evaluation of conformability, wafer separation, and grip ring detachment.
• the adhesive tapes for electronic components according to examples 1 to 3, 5 to 7, and 9 achieved better results in the evaluation of conformability than example 4 because the adhesive layer has a thickness of 30 ⁇ m or more.
• the adhesive tapes for electronic components according to Comparative Examples 1 and 2 showed inferior results in the evaluation of wafer separation in a tensile test conforming to JIS K7161-2:2014 in the TD direction of the laminate of the base film and adhesive layer after irradiation, where A is the load at 20% strain and B is the load at 40% strain, because B [N] - A [N] ⁇ 0 [N].
• Comparative Examples 3 and 4 showed inferior results in the evaluation of grip ring detachment because the combined thickness of the base film and adhesive layer exceeded 170 ⁇ m.

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