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
  • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
  • C09J11/02—Non-macromolecular additives
  • C09J11/06—Non-macromolecular additives organic
• • 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
  • C09J183/00—Adhesives based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Adhesives based on derivatives of such polymers
  • C09J183/04—Polysiloxanes
• • 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
  • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
• • 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]
• • 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
  • C09J7/40—Adhesives in the form of films or foils characterised by release liners
• • 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
  • C09J7/40—Adhesives in the form of films or foils characterised by release liners
  • C09J7/401—Adhesives in the form of films or foils characterised by release liners characterised by the release coating composition
• • 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
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/01—Manufacture or treatment
  • H10W72/015—Manufacture or treatment of bond wires
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W72/00—Interconnections or connectors in packages
  • H10W72/01—Manufacture or treatment
  • H10W72/015—Manufacture or treatment of bond wires
  • H10W72/01504—Manufacture or treatment of bond wires using temporary auxiliary members, e.g. using sacrificial coatings or handle substrates
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/01—Manufacture or treatment
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/01—Manufacture or treatment
  • H10W74/014—Manufacture or treatment using batch processing
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W74/00—Encapsulations, e.g. protective coatings
  • H10W74/01—Manufacture or treatment
  • H10W74/019—Manufacture or treatment using temporary auxiliary substrates
• • 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

Definitions

• the present invention relates to a heat-resistant adhesive film that is applied to protect terminals when resin-encapsulating semiconductor components during the semiconductor package manufacturing process.
• CSP Chip Size/Scale Package
• QFN Quad Flat Non-leaded package
• a method of manufacturing such QFNs is used in which multiple QFN semiconductor chips are arranged on the die pad of the package pattern area of the lead frame, encapsulated in a mold cavity with encapsulating resin, and then cut into individual QFN structures, thereby improving productivity per lead frame area.
• heat-resistant adhesive films that use silicone adhesives such as those described in Patent Document 1
• Such heat-resistant adhesive films are first used by attaching them to the lead frame, and are then used in the semiconductor chip mounting process or wire bonding process.
• Patent Document 2 describes a heat-resistant adhesive tape for use in the semiconductor package manufacturing process that is slightly adhesive at room temperature and whose adhesive strength increases in a high-temperature atmosphere. This heat-resistant adhesive tape is also first attached to a lead frame in the semiconductor package manufacturing process, and is then used in the semiconductor chip mounting process or wire bonding process.
• heat-resistant adhesive film When a heat-resistant adhesive film is attached to a lead frame prior to the semiconductor chip mounting process and wire bonding process, such a heat-resistant adhesive film is required to not only prevent leakage of the sealing resin, but also to have the following characteristics: heat resistance to withstand the high temperatures of the semiconductor chip mounting process or wire bonding process, not to interfere with wire connection in the wire bonding process, and not to leave any adhesive residue on the lead terminals or sealing resin surface when the adhesive film is peeled off after each process in a high-temperature environment.
• heat-resistant adhesive films are required to have low adhesive strength when attached, good adhesion and reworkability (re-application), and to have properties that increase their adhesive strength in the high-temperature environment of the subsequent sealing process to prevent resin leakage.
• the heat-resistant adhesive tape described in Patent Document 2 is configured so that its adhesive strength increases in a high-temperature environment, but to obtain a sufficiently increased adhesive strength, it must be subjected to the high-temperature environment of the semiconductor chip mounting process and the wire bonding process. Even if the heat-resistant adhesive tape described in Patent Document 2 is attached to a lead frame after the wire bonding process, its adhesive strength does not increase sufficiently in the short period of time of about five minutes that it is subjected to the high-temperature environment of the sealing process, so in order to prevent resin leakage, it must be subjected to a separate heat treatment process to increase its adhesive strength.
• a heat-resistant adhesive film that can be attached to the back surface of a lead frame after the wire bonding process, and that has low adhesive strength at room temperature and can increase sufficiently in adhesive strength by simply being exposed to a high-temperature environment for a short period of time.
• the present inventors have found that it is possible to provide such adhesive properties by forming the adhesive layer of the heat-resistant adhesive film from a cured product of an addition-curing silicone adhesive composition that has a phenolic hydroxyl group.
• the adhesive layer discovered is laminated with a separator (release film) that is normally used, the adhesive strength with the separator increases over time during storage, making it difficult to peel off the separator during use.
• the present invention aims to provide a heat-resistant adhesive film that can be attached to the back surface of a lead frame after a wire bonding process in a semiconductor package manufacturing method, the heat-resistant adhesive film having an adhesive layer that has low adhesive strength at room temperature but can increase in adhesive strength sufficiently by simply being exposed to a high-temperature environment for a short period of time, and in which the increase over time in the peel strength between the adhesive layer and the separator is suppressed.
• the inventors After extensive research, the inventors have found that by incorporating phenolic hydroxyl groups into the resin that constitutes the adhesive layer of a heat-resistant adhesive film for semiconductor package manufacturing, the adhesive strength is low at room temperature, and can be sufficiently increased by simply exposing the film to a high-temperature environment for a short period of time. They have also found that by laminating a separator to the adhesive layer via a release layer composed of a long-chain alkyl pendant polymer, it is possible to suppress the increase over time in the peel strength between the adhesive layer and the separator.
• the present invention was completed based on this finding and through further research. That is, the present invention includes the following inventions.
• Item 1 A substrate, a silicone pressure-sensitive adhesive layer laminated on the substrate, and a separator including a release layer laminated on the silicone pressure-sensitive adhesive layer, the release layer is in contact with the silicone adhesive layer, the silicone pressure-sensitive adhesive layer is composed of a cured product of an addition-curable silicone pressure-sensitive adhesive composition and has a phenolic hydroxyl group; the release layer is composed of a long-chain alkyl pendant polymer; A heat-resistant adhesive film for semiconductor package production, wherein the peel strength of the separator from the silicone adhesive layer is 10 to 400 mN/25 mm.
• Item 3 The heat-resistant adhesive film for semiconductor package production according to Item 2, wherein the isocyanate-reactive group is a hydroxyl group.
• Item 4 The heat-resistant adhesive film for semiconductor package production according to any one of Items 1 to 3, wherein the long-chain alkyl group of the long-chain alkyl pendant polymer has 12 or more carbon atoms.
• the heat-resistant adhesive film for a semiconductor package manufacturing process according to any one of Items 1 to 4, wherein the ratio of the separator peel strength from the silicone pressure-sensitive adhesive layer after storing the heat-resistant adhesive film at 60° C. for 96 hours to the separator peel strength from the silicone pressure-sensitive adhesive layer before the storage is 0.9 to 2.0.
• Item 6 The heat-resistant adhesive film for semiconductor package production according to any one of Items 1 to 5, wherein the cured product is an addition-cured product of an adhesive composition comprising an addition-curing silicone adhesive composition and an alkenyl group-containing arylol compound.
• the alkenyl group-containing aryl ol compound is a compound represented by the following formulas (1) to (3):
• Ar is an aryl group;
• R 1 is a direct bond or a hydrocarbon chain which may or may not have a double bond between carbon atoms constituting the main chain,
• R2 is a hydrocarbon chain which may or may not have a double bond between the carbon atoms constituting the main chain.
• Item 7 The heat-resistant adhesive film for semiconductor package production according to item 6, selected from the group consisting of: Item 8.
• the heat-resistant adhesive film for semiconductor package production according to any one of Items 6 to 8, wherein the adhesive composition contains 0.20 to 2.85 mass% of a phenolic hydroxyl group possessed by the alkenyl group-containing arylol compound.
• Item 10 The cured product is an addition cured product of a pressure-sensitive adhesive composition containing a diorganopolysiloxane having an alkenyl group, a crosslinking agent, and an alkenyl-containing arylol compound, The molar ratio of the SiH group (C) contained in the crosslinking agent to the sum of the alkenyl group (A) in the diorganopolysiloxane having an alkenyl group and the alkenyl group (B) in the alkenyl group-containing arylol compound [(C) / ⁇ (A) + (B) ⁇ ] is 0.5 to 3.0.
• the heat-resistant adhesive film for semiconductor package production includes: a wire bonding step of electrically connecting a terminal portion of a lead frame on which a semiconductor chip is mounted to the lead frame; a bonding step of bonding the heat-resistant adhesive film according to claim 1 to a surface of the lead frame opposite to a surface on which the semiconductor chip is mounted after peeling off a separator; a sealing step of sealing the semiconductor chip with a sealing resin;
• the heat-resistant adhesive film for manufacturing a semiconductor package according to any one of claims 1 to 10 further comprising a peeling step of peeling the heat-resistant adhesive film from the lead frame to obtain a semiconductor package.
• the heat-resistant adhesive film of the present invention can be used in a semiconductor package manufacturing method by adhering it to the back surface of a lead frame after the wire bonding process, and has an adhesive layer that has low adhesive strength at room temperature but can increase its adhesive strength sufficiently by simply being exposed to a high-temperature environment for a short period of time, and in which the increase over time in the peel strength between the adhesive layer and the separator is suppressed.
• 1 is a schematic cross-sectional view showing a heat-resistant adhesive film of the present invention.
• 1A to 1C are process diagrams showing an example of a method for producing a semiconductor package using the heat-resistant adhesive film of the present invention.
• the heat-resistant adhesive film of the present invention comprises a substrate, a silicone adhesive layer laminated on the substrate, and a separator including a release layer laminated on the silicone adhesive layer, the release layer is in contact with the silicone adhesive layer, the silicone adhesive layer is made of a cured product of an addition-curing silicone adhesive composition and has a phenolic hydroxyl group, the release layer is made of a long-chain alkyl pendant polymer, the peel strength of the separator from the silicone adhesive layer is 10 to 400 mN/25 mm, and the film is used for manufacturing semiconductor packages.
• FIG. 1 shows a schematic cross-sectional view of an embodiment of the heat-resistant adhesive film of the present invention.
• the heat-resistant adhesive film (10) shown in FIG. 1 includes a substrate (14), a silicone adhesive layer (13) laminated on the substrate (14), and a separator (11) including a release layer (12) laminated on the silicone adhesive layer (13).
• the separator (11) is peeled off from the heat-resistant adhesive film (10) during use, the heat-resistant adhesive film (10) becomes a heat-resistant adhesive film (10') including the substrate (14) and the silicone adhesive layer (13) laminated on the substrate (14).
• the substrate for the heat-resistant adhesive film of the present invention is not particularly limited, but a synthetic resin film or metal foil that can withstand the high temperature environment of 150 to 200°C during the sealing process can be used. From the viewpoint of ease of handling of the adhesive film, it is preferable to use a synthetic resin film as the substrate.
• the synthetic resin is not particularly limited, but a heat-resistant synthetic resin with a melting point of 250°C or higher is preferred, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyetherimide (PEI), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc.
• PET polyethylene terephthalate
• PEN polyethylene naphthalate
• PI polyimide
• PEI polyetherimide
• PSF polysulfone
• PES polyethersulfone
• PES polyphenylene sulfide
• PEEK polyetheretherketone
• the thickness of the substrate is not particularly limited, but from the viewpoint of obtaining stiffness in the substrate, ease of application of the adhesive layer, and/or ease of handling when applying the adhesive film, it is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, and even more preferably 20 ⁇ m or more.
• the upper limit of the thickness of the substrate is not particularly limited, but from the viewpoint of ease of peeling during rework, it is preferably 250 ⁇ m or less, more preferably 150 ⁇ m or less, and even more preferably 100 ⁇ m or less.
• the surface of the substrate on which the adhesive layer is laminated is preferably subjected to a surface treatment to improve adhesion to the adhesive layer.
• surface treatments include corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, and primer treatment.
• the adhesive layer in the heat-resistant adhesive film of the present invention is composed of a cured product of an addition-curing silicone adhesive composition that contains phenolic hydroxyl groups.
• an addition-curing silicone adhesive composition that contains phenolic hydroxyl groups i.e., the addition-curing silicone adhesive composition that contains a phenolic hydroxyl group source
• An addition-curable silicone adhesive composition contains silicone rubber (a long-chain polymer of polydimethylsiloxane having a structure consisting of D units [( CH3 ) 2SiO2 /2 ]) as a basic component, and preferably also contains MQ resin (a three-dimensional silicone resin polymer having a structure consisting of M units [ R3SiO1 /2 : R is a monovalent organic group such as methyl or phenyl] and Q units [SiO4 /2 ]).
• silicone rubber a long-chain polymer of polydimethylsiloxane having a structure consisting of D units [( CH3 ) 2SiO2 /2 ]
• MQ resin a three-dimensional silicone resin polymer having a structure consisting of M units [ R3SiO1 /2 : R is a monovalent organic group such as methyl or phenyl] and Q units [SiO4 /2 ].
• the addition-curing silicone adhesive composition preferably contains, specifically, a diorganopolysiloxane having two or more alkenyl groups in one molecule as a silicone rubber component, an organohydrogenpolysiloxane having SiH groups as a crosslinking agent, and a platinum catalyst, and more preferably further contains an MQ resin.
• the alkenyl group is preferably a vinyl group.
• the diorganopolysiloxane having two or more alkenyl groups in one molecule include (i) linear diorganopolysiloxanes having vinyl groups only at both ends, (ii) linear diorganopolysiloxanes having vinyl groups at both ends and in the side chains, (iii) branched diorganopolysiloxanes having vinyl groups only at the ends, and (iv) branched diorganopolysiloxanes having vinyl groups at the ends and in the side chains.
• the diorganopolysiloxane having two or more alkenyl groups in one molecule a combination of the above compounds (i) and (iii) is preferred, and in this combination, the above compound (iii) can be used in an amount of preferably 20 to 70 parts by mass, more preferably 25 to 60 parts by mass, and even more preferably 30 to 57 parts by mass, 35 to 57 parts by mass, 40 to 57 parts by mass, 45 to 57 parts by mass, or 50 to 57 parts by mass per 100 parts by mass of the above compound (i).
• the weight average molecular weight of the diorganopolysiloxane having two or more alkenyl groups in one molecule is preferably 20,000 or more, more preferably 40,000 or more, even more preferably 60,000 or more, even more preferably 70,000 or more, 75,000 or more, 100,000 or more, 200,000 or more, or 300,000 or more, from the viewpoint of appropriately controlling the crosslink density and suppressing excessive adhesive strength to the adherend.
• the weight average molecular weight is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC).
• the alkenyl group content is preferably 3.2 ⁇ 10 -5 mol/g or less, more preferably 3 ⁇ 10 -5 mol/g or less, and even more preferably 2.8 ⁇ 10 -5 mol/g or less, 2.7 ⁇ 10 ⁇ 5 mol/g, 2 ⁇ 10 ⁇ 5 mol/g or less, 1.7 ⁇ 10 ⁇ 5 mol/g or less, 1.4 ⁇ 10 ⁇ 5 mol/g or less, 1.1 ⁇ 10 ⁇ 5 mol/g or less, 0.85 ⁇ 10 ⁇ 5 mol/g or less, 0.8 ⁇ 10 ⁇ 5 mol/g or less, or 0.75 ⁇ 10 ⁇ 5 mol/g or less.
• the crosslinking agent may be, for example, organohydrogenpolysiloxane.
• the organohydrogenpolysiloxane preferably has at least three SiH groups in one molecule, and the molecular shape may be linear, branched, or cyclic.
• the SiH groups contained in the organohydrogenpolysiloxane undergo an addition reaction with the alkenyl groups of the diorganopolysiloxane having the alkenyl groups to form a silicone cured product (crosslinked structure).
• the weight average molecular weight of the crosslinking agent is preferably 1,500 or more, more preferably 1,800 or more, even more preferably 2,000 or more, even more preferably 2,200 or more, 2,300 or more, 2,350 or more, or 2,450 or more, and the weight average molecular weight is preferably 3,500 or less, more preferably 3,300 or less, even more preferably 3,000 or less, even more preferably 2,800 or less, 2,600 or less, or 2,450 or less.
• the SiH group content of the crosslinking agent is preferably 0.3 ⁇ 10-2 mol/g or more, more preferably 0.6 ⁇ 10-2 mol/g or more, even more preferably 0.7 ⁇ 10-2 mol/g or more, 1.0 ⁇ 10-2 mol/g or more, 1.3 ⁇ 10-2 mol/g, or 1.5 ⁇ 10-2 mol/g, and the SiH group content is preferably 2.2 ⁇ 10-2 mol/g or less, more preferably 2.0 ⁇ 10-2 mol/g or less, even more preferably 1.8 ⁇ 10-2 mol/g or less, even more preferably 1.7 ⁇ 10-2 mol/g or less, 1.3 ⁇ 10-2 mol/g or less, 1.0 ⁇ 10-2 mol/g or less, or 0.8 ⁇ 10-2 mol/g or less.
• the platinum catalyst used in the curing reaction of the silicone composition may be a known one, and specific examples include chloroplatinic acids such as chloroplatinic acid and chloroplatinic acid, alcohol compounds or aldehyde compounds of chloroplatinic acid, and complex salts of chloroplatinic acid and various olefins.
• chloroplatinic acids such as chloroplatinic acid and chloroplatinic acid
• alcohol compounds or aldehyde compounds of chloroplatinic acid and complex salts of chloroplatinic acid and various olefins.
• platinum catalysts preferred are complex salts of chloroplatinic acid and various olefins, and more preferred are platinum-alkenylsiloxane complexes.
• the addition-curing silicone adhesive composition contains a conventional MQ resin consisting of M units ( R3SiO1 /2 : R is a monovalent organic group such as an alkyl group such as a methyl group or an aryl group such as a phenyl group, preferably an alkyl group, and more preferably a methyl group) and Q units (SiO4 /2 ).
• the weight average molecular weight of the MQ resin is preferably 5,000 or more, more preferably 6,000 or more, even more preferably 6,500 or more or 6,800 or more, and the weight average molecular weight is preferably 8,000 or less, more preferably 7,500 or less, even more preferably 7,100 or less.
• the amount of MQ resin to be blended can be appropriately determined depending on the required adhesive strength.
• the cured product of the silicone adhesive composition constituting the silicone adhesive layer of the present invention also has phenolic hydroxyl groups.
• the phenolic hydroxyl groups in the cured product do not contribute much to the adhesion to the lead frame, which is the adherend, at room temperature, but in a high temperature environment, the phenolic hydroxyl groups immediately orient themselves toward the lead frame surface, which is the adherend, and the adhesion increases.
• the adhesive strength to the lead frame is low at room temperature, but when the adhesive is applied to the lead frame and then exposed to a high temperature environment during resin sealing, the adhesive strength to the lead frame can increase in a short time.
• the cured product of the silicone adhesive composition constituting the silicone adhesive layer of the present invention has phenolic hydroxyl groups and the cured product of the silicone adhesive composition has a crosslinked structure, so that even if the adhesive strength to the lead frame increases, the cohesive force of the adhesive layer can suppress the occurrence of glue residue when peeled off.
• the content of the phenolic hydroxyl group in the pressure-sensitive adhesive composition is preferably 0.20 to 2.85% by mass. From the viewpoint of further enhancing the effect of preventing resin leakage by improving the effect of increasing the adhesive strength in a high-temperature environment, the content of the phenolic hydroxyl group in the pressure-sensitive adhesive composition is more preferably 0.45 to 2.85% by mass, more preferably 0.50 to 2.85% by mass, 1 to 2.85% by mass, 1.20 to 2.85% by mass, or 1.25 to 2.85% by mass.
• the content of the phenolic hydroxyl group in the pressure-sensitive adhesive composition is more preferably 0.20 to 2.60% by mass, more preferably 0.20 to 2.55% by mass, 0.20 to 2.10% by mass, 0.20 to 1.80% by mass, 0.20 to 1.30% by mass, or 0.20 to 1.28% by mass.
• the content of phenolic hydroxyl groups in the pressure-sensitive adhesive composition is a value calculated by the following calculation formula 1.
• Phenolic hydroxyl group content (mass %) ⁇ (M1 ⁇ N) ⁇ M2) ⁇ W1 ⁇ W2 ⁇ 100
• M1 chemical formula weight of phenolic hydroxyl group
• N number of phenolic hydroxyl groups in the alkenyl group-containing arylol compound
• M2 molecular weight of the alkenyl group-containing arylol compound
• W1 mass of the alkenyl group-containing arylol compound in the pressure-sensitive adhesive composition
• W2 total mass of the pressure-sensitive adhesive composition
• An alkenyl-containing arylol compound is a compound that has at least one alkenyl group and one or more phenolic hydroxyl groups in the molecule.
• alkenyl group-containing arylol compound examples include the compounds of the following formulae (1) to (3).
• Ar is an aryl group, preferably a phenyl group or a naphthyl group, more preferably a phenyl group.
• R 1 is a direct bond (sigma bond) or a hydrocarbon chain (the number of carbon atoms may be, for example, 1 to 14) which may or may not have a double bond between the carbon atoms constituting the main chain, and is preferably a direct bond (sigma bond) or an alkylene group having 1 to 6 carbon atoms (more preferably 1 to 4, even more preferably 1 to 3, and even more preferably 1 to 2).
• R 2 is a hydrocarbon chain (the number of carbon atoms may be, for example, 1 to 14) which may or may not have a double bond between the carbon atoms constituting the main chain, and is preferably an alkylene group having 1 to 8 carbon atoms (more preferably 1 to 6, and even more preferably 1 to 4).
• alkenyl group-containing arylol compounds include vinylphenols such as 2-vinylphenol, 3-vinylphenol, 4-vinylphenol, and 2-methoxy-4-vinylphenol; allylphenols such as 2-allylphenol, 4-allylphenol, 4-methyl-2-allylphenol, 6-methyl-2-allylphenol, and eugenol; propenylphenols such as 2-(1-propenyl)phenol and isoeugenol; butenylphenols such as 2-(3-butenyl)phenol and 2-(1-ethyl-3-butenyl)phenol; long-chain alkenylphenols such as cardanol; allyloxyphenols such as 2-(allyloxy)phenol and 4-(allyloxy)phenol; and allylnaphthols such as 2-allyl-1-naphthol and 3-allyl-1-naphthol. These can be used alone or in combination of two or more. Among these, allylphenol is
• the molar ratio [(C)/ ⁇ (A)+(B) ⁇ ] of the SiH group (C) contained in the crosslinking agent to the sum of the alkenyl group (A) in the diorganopolysiloxane having an alkenyl group and the alkenyl group (B) in the arylol compound containing an alkenyl group contained in the pressure-sensitive adhesive composition is preferably 0.5 to 3.0.
• the molar ratio is more preferably 0.8 to 3.0, and even more preferably 1.0 to 3.0, 1.1 to 3.0, or 1.2 to 3.0.
• the molar ratio is more preferably 0.5 to 2.0, even more preferably 0.5 to 1.5, and even more preferably 0.5 to 1.28, 0.5 to 1.26, 0.5 to 1.24, 0.5 to 1.22, or 0.5 to 1.20.
• Additives may be added to the pressure-sensitive adhesive composition as appropriate to improve other properties.
• additives include organic/inorganic particles, colorants, silicone oil, silicone resin, silane coupling agents, and antioxidants.
• the silicone cured product having phenolic hydroxyl groups can be obtained by curing the above-mentioned adhesive composition (an adhesive composition containing a silicone composition component of an addition-curing silicone adhesive, an alkenyl-group-containing arylol compound serving as a source of phenolic hydroxyl groups, and a crosslinking agent) by addition reaction.
• the SiH groups contained in the crosslinking agent undergo addition reaction with the alkenyl groups in the diorganopolysiloxane having alkenyl groups, and also with the alkenyl groups in the alkenyl-group-containing arylol compound, resulting in a silicone cured product having phenolic hydroxyl groups.
• Reaction conditions for obtaining the cured product include, for example, 160 to 200°C, preferably 170 to 190°C, more preferably 175 to 185°C, for example, 0.5 to 5 minutes, preferably 1 to 3 minutes.
• the adhesive layer of the heat-resistant adhesive film of the present invention has low adhesive strength when attached to a lead frame at room temperature, and the adhesive strength increases to a level that prevents resin leakage in the short time (e.g., 2.5 to 5.5 minutes, preferably 4.5 to 5.5 minutes) until the sealing is completed in the high-temperature environment during resin sealing. Furthermore, even if high-temperature treatment is performed for several hours (e.g., 1.2 to 3.5 hours, preferably 1.2 to 2.5 hours) as a post-mold cure after sealing, the adhesive strength does not increase significantly and the film can be easily peeled off.
• the adhesive strength of the adhesive layer of the heat-resistant adhesive film of the present invention at room temperature is preferably in the range of 50 to 500 mN/25 mm, and more preferably in the range of 90 to 350 mN/25 mm, as the peeling force against the copper foil when the heat-resistant adhesive film is attached to copper foil and peeled off at a peeling angle of 180° and a peeling speed of 300 mm/min, because it is easy to attach to a lead frame without applying pressure due to the self-adhesive force of the silicone adhesive layer, which has good wettability, and because it also has excellent reworkability.
• the adhesive layer of the heat-resistant adhesive film of the present invention has an adhesive strength during short-term heating, which is preferably 600 mN/25 mm or more, more preferably 900 mN/25 mm or more, when the heat-resistant adhesive film is attached to copper foil and heated at 175°C for 3 minutes, and after 3 minutes, the heat-resistant adhesive film is peeled off at a peel angle of 90° and a peel speed of 300 mm/min under heating at 175°C.
• the peel angle at this time is measured at a peel angle of 90°, assuming that the resin pressure (peel force) applied to the heat-resistant adhesive film during sealing is perpendicular to the adhesion surface.
• 175°C for 3 minutes is a typical process temperature in transfer molding for semiconductor sealing, and a typical time from when the lead frame is mounted on the mold to when resin sealing begins.
• the heat-resistant adhesive film of the present invention is attached to a copper foil, heat-treated at 175°C for 5 minutes, then a pressure of 670 kgf/ m2 is applied to the heat-resistant adhesive film, heat-treated at 175°C for 90 minutes, cooled to room temperature, and the heat-resistant adhesive film is peeled off at a peel angle of 180° and a peel speed of 300 mm/min.
• the copper foil peel strength is preferably 3500 mN/25 mm or less, more preferably 2600 mN/25 mm or less.
• the pressure and heat treatment conditions at this time are typical treatment conditions for post-mold cure after sealing.
• the various adhesive strengths of the adhesive layer of the heat-resistant adhesive film of the present invention can be controlled by changing at least one of the conditions of the molecular weight and crosslink density of the silicone rubber in the adhesive composition used in the adhesive layer, and the ratio of the MQ resin.
• the thickness of the silicone adhesive layer of the present invention is not particularly limited, but may be, for example, 2 to 50 ⁇ m.
• the lower limit of the thickness range (2 to 50 ⁇ m) may be preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, 15 ⁇ m or more, 20 ⁇ m or more, or 25 ⁇ m or more, from the viewpoint of improving adhesion to the lead frame surface by improving conformability to the irregularities of the lead frame surface that is the adherend
• the upper limit of the thickness range (2 to 50 ⁇ m) is preferably 40 ⁇ m or less, more preferably 35 ⁇ m or less, and even more preferably 32 ⁇ m or less, 15 ⁇ m or less, 10 ⁇ m or less, or 7 ⁇ m or less, from the viewpoint of suppressing deformation distortion due to the clamp pressure that fixes the lead frame during resin sealing.
• the adhesive composition is applied uniformly to a substrate to a predetermined thickness either as is or in the form of a coating liquid whose viscosity has been adjusted with a solvent or the like, the solvent is dried, and the adhesive composition is cured by heating, thereby forming a silicone adhesive layer.
• Examples of methods for applying the adhesive composition include a gravure coater, a bar coater, a comma knife coater, and a die coater.
• the heat-resistant adhesive film of the present invention is laminated with a separator (release film) containing a release layer in such a way that the release layer surface is in contact with the silicone adhesive layer surface, in order to protect the adhesive surface of the silicone adhesive layer until it is attached to the lead frame and to improve handling.
• the separator only needs to include a release layer as the outermost layer, and specifically, the separator is made up of a multilayer including a separator substrate and a release layer laminated on the separator substrate, with the release layer forming the outermost layer of the separator.
• One or more other layers e.g., an adhesive layer, etc.
• the separator (11) is made up of a separator substrate (15) and a release layer (12) laminated on the separator substrate (15).
• the material of the separator substrate can be, for example, a synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, or polyurethane. From the viewpoint of heat resistance and strength, a polyethylene terephthalate film is preferred as the separator substrate.
• the thickness of the separator substrate is usually about 6 to 200 ⁇ m, and from the viewpoint of handleability and cost, it is about 12 to 100 ⁇ m, preferably 20 to 80 ⁇ m, and more preferably 40 to 60 ⁇ m.
• the release layer is composed of a long-chain alkyl pendant polymer, which has low peel strength against the silicone adhesive layer containing phenolic hydroxyl groups, whose adhesive strength with the lead frame increases in the high-temperature environment of the sealing process, and which suppresses the increase in separator peel strength over time, as well as suppressing the decrease in the adhesive strength increase effect of the adhesive layer in high-temperature environments.
• Long-chain alkyl pendant polymers are those in which long-chain alkyl groups exist as pendant side chains on a main chain polymer, and examples include (I) polymers containing vinyl monomer units having long-chain alkyl groups, and (II) modified polymers in which a polymer having an isocyanate-reactive group on the side chain is reacted with a monofunctional isocyanate having a long-chain alkyl group.
• the long-chain alkyl groups of the vinyl monomer units in the above polymer (I), and the long-chain alkyl groups of the monofunctional isocyanate in the above modified polymer (II) are groups that constitute the "long-chain alkyl" group of the long-chain alkyl pendant polymer, and specific examples are as described below.
• the vinyl monomer having a long-chain alkyl group is a monomer represented by CH 2 ⁇ CR 3 R 4 (R 3 represents a hydrogen atom or a methyl group, and R 4 represents a group containing a long-chain alkyl group), and examples thereof include esters of (meth)acrylic acid and monohydric alcohols having a long-chain alkyl group.
• the polymer (I) may contain one of these vinyl monomer units having a long-chain alkyl group alone, or may contain a combination of two or more of them.
• the monomer units constituting the polymer (I) may be composed of a vinyl monomer having a long-chain alkyl group, or may further contain a comonomer unit not having a long-chain alkyl group.
• a comonomer unit is further contained, the content of the comonomer unit in the polymer is, for example, 35 to 60 mol%, preferably 40 to 55 mol%, and more preferably 45 to 50 mol%.
• examples of the isocyanate-reactive groups that the polymer to be modified has on its side chain include -OH (which forms a urethane bond in a reaction with isocyanate) and -NH (which forms a urea bond in a reaction with isocyanate).
• the polymer having an isocyanate-reactive group on its side chain may have a monomer unit having an isocyanate-reactive group on its side chain, and examples of such monomer units include a vinyl alcohol monomer unit, an ethyleneimine monomer unit, and a sugar residue to which a hydroxyl-containing group has been introduced via an ether bond.
• the polymer having an isocyanate-reactive group on its side chain may contain one of these monomer units having an isocyanate-reactive group on its side chain alone, or may contain two or more of them in combination.
• the polymer having an isocyanate-reactive group on its side chain may be composed of a monomer unit having an isocyanate-reactive group on its side chain, or may further contain a comonomer unit not having an isocyanate-reactive group on its side chain.
• the content of the comonomer unit in the polymer is, for example, 35 to 60 mol%, preferably 40 to 55 mol%, and more preferably 45 to 50 mol%.
• polymers having an isocyanate-reactive group in the side chain include polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyethyleneimine, and cellulose derivatives in which a hydroxyl group-containing group has been introduced via an ether bond (hydroxyethyl cellulose, hydroxypropyl cellulose, methylhydroxyethyl cellulose, methylhydroxypropyl cellulose, etc.).
• the release layer may contain one of the above long-chain alkyl pendant polymers alone or in combination of two or more.
• the above modified polymer (II) (a modified polymer obtained by reacting a monofunctional isocyanate having a long-chain alkyl group with a polymer having an isocyanate-reactive group in the side chain); more preferably, a modified polymer obtained by reacting a monofunctional isocyanate having a long-chain alkyl group with a polymer having -OH in the side chain; even more preferably, a modified polymer obtained by reacting a monofunctional isocyanate having a long-chain alkyl group with a polymer having a vinyl alcohol monomer unit; and even more preferably, a modified polymer obtained by reacting a monofunctional isocyanate having a long-chain alkyl group with an ethylene-vinyl alcohol copolymer.
• the long-chain alkyl group of the long-chain alkyl pendant polymer is preferably linear from the viewpoint of peelability from the silicone adhesive layer.
• the carbon number of the long-chain alkyl group is, for example, 12 or more, preferably 14 or more, from the viewpoint of reducing the peel strength from the silicone adhesive layer and minimizing fluctuations in the separator peel strength over time, and, from the viewpoint of making it easier to ensure the solvent solubility of the long-chain alkyl pendant polymer, for example, 28 or less, preferably 22 or less, more preferably 18 or less.
• the weight average molecular weight (Mw) of the long-chain alkyl pendant polymer is preferably 120,000 or more, more preferably 140,000 or more, even more preferably 150,000 or more, and even more preferably 20,000 or more or 22,000 or more, from the viewpoint of reducing component migration that reduces the adhesive strength of the release layer and suppressing an increase in the adhesive strength of the silicone adhesive layer in a high-temperature environment, and is preferably 300,000 or less, more preferably 250,000 or less, from the viewpoint of easily ensuring the solvent solubility of the long-chain alkyl pendant polymer.
• the weight average molecular weight (Mw) is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).
• the separator peeling force of the heat-resistant adhesive film of the present invention is preferably in the range of 10 to 400 mN/25 mm. From the viewpoint of obtaining a peeling force suitable enough to process the separator without peeling during production, the separator peeling force is preferably 20 to 400 mN/25 mm, more preferably 40 to 400 mN/25 mm, even more preferably 100 to 400 mN/25 mm, and even more preferably 140 to 400 mN/25 mm, 170 to 400 mN/25 mm, or 200 to 400 mN/25 mm.
• the separator peeling force is preferably 10 to 300 mN/25 mm, more preferably 10 to 200 mN/25 mm.
• the separator peel strength is the value measured when a separator is attached to the adhesive layer surface, aged for 7 days in an environment of 23 ⁇ 2°C and 50 ⁇ 10% RH, and then the separator side is peeled off at a peel angle of 180° and a peel speed of 300 mm/min.
• the ratio of the separator peeling force after storing a heat-resistant adhesive film with a separator attached at 60°C for 96 hours to the separator peeling force before storage is preferably in the range of 0.9 to 2.0, and more preferably in the range of 0.9 to 1.5.
• this separator peeling force ratio is in the above range, there is little fluctuation in the peeling force over time, and the product has excellent quality stability even when stored for a long period of time (one year or more).
• the release layer by selecting a long-chain alkyl pendant polymer as the constituent polymer of the release layer, it is possible to avoid impairing the increase in adhesive strength of the silicone adhesive layer in contact with the release layer in the high-temperature environment of the sealing process. This is thought to be because the components of the release layer of the separator, which are composed of a long-chain alkyl pendant polymer, are unlikely to migrate to the adhesive layer, which is composed of a cured product of an addition-curing silicone adhesive composition and has a phenolic hydroxyl group. The migration of the release layer components can be confirmed as the residual adhesive rate (also called the residual adhesion rate) of the silicone adhesive layer after the separator is peeled off.
• the residual adhesive rate also called the residual adhesion rate
• the residual adhesive rate for the adhesive strength measured under heating at 175°C is preferably 90% or more, more preferably 95% or more, and even more preferably 99% or more.
• the residual adhesive rate is a value calculated by the following calculation formula 2.
• Residual adhesion rate (%) (residual adhesion strength F/initial adhesion strength F0) x 100 [Initial adhesive strength F0]
• a separator for the heat-resistant adhesive film a plain polyethylene terephthalate film not forming a release layer is attached to the adhesive layer surface of the heat-resistant adhesive film, and after aging for 7 days in an environment of 23 ⁇ 2°C and 50 ⁇ 10% RH, the separator is peeled off and the adhesive layer surface of the heat-resistant adhesive film is attached to copper foil, followed by heat treatment at 175°C for 3 minutes.
• the heat-resistant adhesive film is peeled off at a peel angle of 90° and a peel speed of 300 mm/min under heating at 175°C, and the adhesive strength measured as the peel strength against the copper foil is defined as the initial adhesive strength F0.
• residual adhesive strength F residual adhesive strength
• the release layer side of a polyethylene terephthalate film having a release layer formed thereon is attached to the adhesive layer side of the heat-resistant adhesive film, and the film is aged for 7 days in an environment of 23 ⁇ 2°C and 50 ⁇ 10% RH. After further storage at 60°C for 96 hours, the film is returned to room temperature and the separator is peeled off.
• the adhesive layer side of the heat-resistant adhesive film is attached to copper foil, which is then heat-treated at 175°C for 3 minutes. After 3 minutes, the heat-resistant adhesive film is peeled off under heating at 175°C at a peel angle of 90° and a peel speed of 300 mm/min.
• the adhesive strength measured as the peel strength against the copper foil is defined as the residual adhesive strength F.
• the thickness of the separator release layer is preferably in the range of 0.02 to 1.0 ⁇ m from the viewpoint of film uniformity and productivity. Within this range, a uniform coating film can be easily formed, and peelability from the silicone adhesive layer of the present invention and quality stability can be easily ensured.
• the release layer of the separator can be formed by dissolving a long-chain alkyl pendant polymer in a solvent to create a coating liquid, which is then uniformly coated to a specified thickness on the synthetic resin film to be used as the separator, and then heated and dried to form the release layer.
• Examples of methods for applying the coating liquid for the separator release layer include a gravure coater, a bar coater, a comma knife coater, a die coater, and a reverse coater.
• the heat-resistant adhesive film of the present invention is used by being attached to protect terminals when a semiconductor component is resin-encapsulated in a semiconductor package manufacturing process.
• a method for manufacturing a semiconductor package using the heat-resistant adhesive film of the present invention includes the following steps. a wire bonding step of electrically connecting a terminal portion of a lead frame on which a semiconductor chip is mounted to the semiconductor chip; a bonding step of bonding the heat-resistant adhesive film to a surface of the lead frame opposite to a surface on which the semiconductor chip is mounted after peeling off the separator; a sealing step of sealing the semiconductor chip with a sealing resin; and a peeling step of peeling the heat-resistant adhesive film from the lead frame to obtain a semiconductor package.
• the heat-resistant adhesive film of the present invention can increase its adhesiveness to a degree that can suppress resin leakage within a short period of time during the sealing process, so it is preferable that the manufacturing method for the semiconductor package does not include a separate heating step between the bonding step and the sealing step.
• the heat-resistant adhesive film of the present invention has an excellent property of increasing adhesiveness in a short time as described above, and also has excellent peelability. Therefore, the manufacturing method of the semiconductor package can include a post-mold curing step by heating and pressing between the sealing step and the peeling step.
• the temperature condition in the post-mold curing step is, for example, 170 to 180°C, and the heating time is, for example, 1.2 to 3.5 hours, preferably 1.2 to 2.5 hours.
• the pressure condition in the post-mold curing step is, for example, 600 to 750 kgf/ m2 , preferably 630 to 720 kgf/ m2 , more preferably 650 to 700 kgf/ m2 .
• FIG 2 is a process diagram of an example of a method for manufacturing a semiconductor package using the heat-resistant adhesive film of the present invention (heat-resistant adhesive film from which the separator has been peeled off (part (10') in Figure 1)).
• the method for manufacturing a semiconductor package includes at least the steps of (b) mounting the semiconductor chip 30 on the lead frame 20, (c) a wire bonding step for electrically connecting the semiconductor chip 30 to the terminal portion 22 of the lead frame 20, (d) a bonding step for bonding the heat-resistant adhesive film 10' after peeling off the separator to the lead frame 20, (e) a sealing step for sealing the semiconductor chip 30 with sealing resin 50, (f) a peeling step for peeling off the heat-resistant adhesive film from the lead frame 20 to obtain a QFN unit 60, and (g) a dicing step for dividing the QFN unit 60 to obtain individual QFN packages 70.
• a lead frame 20 is prepared, which has at least a semiconductor chip mounting area 21, a terminal area 22, and an opening 23.
• the lead frame 20 is made of a metal such as copper, and has multiple QFN terminal patterns engraved on it.
• the electrical contact areas may be coated (plated) with a material such as silver, nickel, palladium, or gold.
• the lead frame 20 is generally 100 to 300 ⁇ m thick.
• the lead frame 20 has the individual QFN patterns regularly arranged in a lattice pattern so that it can be easily cut into pieces during the dicing process.
• the semiconductor chip mounting process is a process of fixing the semiconductor chip 30 to the semiconductor chip mounting section 21 of the lead frame 20, as shown in FIG. 2(b).
• a die attachment material such as conductive paste, thermosetting adhesive, or adhesive tape is used to fix the semiconductor chip 30 to the semiconductor chip mounting section 21.
• the adhesive is generally heated and hardened at a temperature of about 150 to 200°C, and the semiconductor chip 30 is fixed and mounted on the semiconductor chip mounting section 21.
• a wire bonding process is performed in which the semiconductor chip 30 and the terminal portion 23 of the lead frame 20 are electrically connected with a bonding wire 40.
• a bonding wire 40 For example, a gold wire or an aluminum wire is used as the bonding wire 40.
• the bonding is performed in a state where the chip is heated to 120 to 250°C, by combining ultrasonic vibration energy and compression energy due to applied pressure.
• the heat-resistant adhesive film 10' from which the separator has been removed is bonded to the surface (lower surface) of the lead frame 20 on which the semiconductor chip 30 is not mounted, so that the adhesive layer is in contact with the lead frame 20.
• a lamination method or the like is a suitable method for bonding the heat-resistant adhesive film to the lead frame 20.
• sealing resin 50 a conventionally known material is used, for example, a mixture of epoxy resin and inorganic filler.
• the heating temperature during resin sealing is, for example, 170 to 180°C, and the heating time is several minutes (for example, 2.5 to 5.5 minutes, preferably 4.5 to 5.5 minutes).
• a heat treatment (post-mold cure process) is carried out to stabilize the physical properties of the encapsulating resin.
• the temperature conditions in the post-mold cure process are, for example, 170 to 180°C, and the heating time is, for example, 1.2 to 3.5 hours, preferably 1.2 to 2.5 hours.
• the heat-resistant adhesive film 10' attached to the lead frame 20 is peeled off to obtain a QFN unit 60 in which multiple QFN packages are arranged.
• the dicing process is a process in which the QFN unit 60 is cut into individual QFN packages 70 by dicing along the outer periphery of each QFN package 50, as shown in FIG. 2(g).
• the heat-resistant adhesive film of the present invention will be described in detail below with examples and comparative examples, but the present invention is not limited to these examples.
• release treatment agents 1 to 3 are resin compositions for release layers.
• release treatment agents 1 to 3 are resin compositions for release layers.
• a release treatment agent 3 was applied by bar coating to one side of a polyethylene terephthalate film having a thickness of 50 ⁇ m so that the thickness of the release layer after the solvent was dried would be 0.1 ⁇ m, and the coating was cured by heating in a gear oven at 150° C. for 1 minute to produce a separator 4 including a release layer.
• Example 1 Adhesive layer coating solution 1 was applied with an applicator to the corona-treated surface of a 25 ⁇ m-thick polyimide film that had been corona-treated on one side, so that the adhesive layer would have a thickness of 12 ⁇ m after the solvent was dried, and then the coating was heated and cured in a Gear oven at 180° C. for 2 minutes to form an adhesive layer. Separator 1 was then laminated using a rubber roller so that the release layer surface was in contact with the adhesive layer surface, and the film was then aged for 7 days at 23° C. and 50% RH to obtain the adhesive film of Example 1.
• Examples 2 to 8, Comparative Examples 1 to 3 The pressure-sensitive adhesive films of Examples 2 to 8 and Comparative Examples 1 to 3 were obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive coating solution 1 and separator 1 in Example 1 were replaced with the combinations of the pressure-sensitive adhesive layer coating solution and separator shown in Table 3.
• the measured peel force values and evaluation results of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 3.
• ⁇ The separator peel strength is 10 mN/25 mm or more and 400 mN/25 mm or less, and the peel strength ratio to the separator peel strength before storage (after storage/before storage) is 1.5 or less.
• the separator peel strength is 10 mN/25 mm or more and 400 mN/25 mm or less, and the peel strength ratio to the separator peel strength before storage (after storage/before storage) is more than 1.5 and 2.0 or less.
• ⁇ The separator peel strength is less than 10 mN/25 mm or more than 400 mN/25 mm.
• ⁇ Preparation of copper foil attachment sample 1> A sample measuring 25 mm wide x 250 mm long was cut out from each of the adhesive films of Examples 1 to 8 and Comparative Examples 1 to 3, and the adhesive layer surface of the cut out sample was attached to a rolled copper foil measuring 50 mm wide x 120 mm long x 50 ⁇ m thick, which was then pressed from above with a 2 kg roller to obtain copper foil attached sample 1.
• Four copper foil attached samples 1 were prepared for each adhesive film for measuring adhesive strength before and after heat treatment and evaluating adhesive residue.
• the copper foil-bonded sample 1 was then sandwiched between SUS plates, and a load of 670 kgf/m 2 was applied to the copper foil-bonded sample 1 from above the SUS plates, and a pressurized heat treatment was performed for 90 minutes in a gear oven at 175° C. (corresponding to the conditions of the post-mold curing step between steps (e) and (f) in FIG. 2). Thereafter, the sample was removed from the gear oven and left in an environment of 23° C. and 50% RH for 5 minutes, and then, in an environment of 23° C.
• the peel strength was measured when the adhesive film of the copper foil-attached sample 1 was peeled from the rolled copper foil at a peel angle of 180° and a peel speed of 300 mm/min using a tensile tester in accordance with JIS Z0237:2009, and this measured value was taken as the adhesive strength (mN/25 mm) after heat treatment.
• the measurement results of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 3.
• the lead frame used was a copper plate having a nickel-plated layer, a palladium-plated layer, and a gold-plated layer in that order, and had the following specifications [32QFN (CD194, plating; PD2L+Au) 32LQFN PADSIZE 3.0SQMM, manufactured by Shinko Electric Industries Co., Ltd.].
• (Lead frame specifications) [Dimensions] 55mm x 58mm, [Arrangement] Matrix arrangement of 8 x 8 QFN patterns (total 64), [Package size] 5mm x 5mm, [Number of pins] 32
• the pressure-heat treatment time was set to two levels, 90 minutes or 180 minutes (corresponding to the conditions of the post-mold curing step between steps (e) and (f) in FIG. 2).
• the copper foil-attached sample 1 was removed from the gear oven and left to stand for 5 minutes in an environment of 23°C and 50% RH, and then, in an environment of 23°C and 50% RH, the adhesive film of the copper foil-attached sample 1 was peeled off from the rolled copper foil using a tensile tester at a peel angle of 180° and a peel speed of 500 mm/min, and the surface of the rolled copper foil from which the adhesive film had been peeled off was visually inspected and evaluated according to the following criteria.
• the evaluation results of Examples 1 to 8 and Comparative Examples 1 to 3 are shown in Table 3.
• the residual adhesion rate of the adhesive layer formed with adhesive layer coating liquid 1 after peeling off separator 1 or 2 was calculated. Specifically, the residual adhesion rate was calculated based on the above-mentioned calculation formula 2. As a result, the residual adhesion rate of the adhesive layer formed with adhesive layer coating liquid 1 after peeling off separator 1 was 91%, and the residual adhesion rate of the adhesive layer formed with adhesive layer coating liquid 1 after peeling off separator 2 was 96%.

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