Method for producing die attach adhesive film sheet

Abstract

Provided herein is a method for manufacturing a die-attach adhesive film sheet, the method comprising the steps of: providing a first release substrate layer, a die-attach adhesive layer, and a dicing tape layer; and bonding the first release substrate layer, the die-attach adhesive layer, and the dicing tape layer in that order to form a multilayer structure; processing the multilayer structure to form a circular preformed die-attach adhesive film sheet, wherein a Z-direction indentation is formed in the first release substrate during processing; and removing the first release substrate with the Z-direction indentation from the die-attach adhesive layer and placing a second release substrate in contact with the die-attach adhesive layer in its place.

Description

[Technical Field]

[0001] Provided herein is a method for making a die attach adhesive film sheet. [Background technology]

[0002] U.S. Patent No. 8,470,115 (Tanaka) describes a method for manufacturing a semiconductor device, comprising: a step of peeling a laminate comprising the adhesive layer, the pressure-sensitive adhesive layer and the base film in the adhesive sheet from the release substrate of the adhesive sheet, which comprises a release substrate, an adhesive layer, a pressure-sensitive adhesive layer and a base film laminated in this order, and attaching the laminate to a semiconductor wafer via the adhesive layer, thereby obtaining a semiconductor wafer having the laminate; a step of dicing the semiconductor wafer having the laminate to obtain a semiconductor element having a laminate of a predetermined size; A step of irradiating the adhesive layer with a high-energy beam to reduce the adhesive strength of the adhesive layer to the adhesive layer, and then peeling the adhesive layer and the base film from the adhesive layer to obtain a semiconductor element having an adhesive layer; and a step of adhering the semiconductor element having the adhesive layer to a support member for mounting the semiconductor element via the adhesive layer; Including, the adhesive layer has a predetermined first planar shape and is formed on a portion of the release substrate; a first cut is formed in the release substrate along the periphery of the planar shape of the adhesive layer from the side that contacts the adhesive layer; The thickness of the release substrate is 30 to 50 μm; and The claimed method relates to a method wherein the depth of the first cut is greater than 0 μm and less than 25 μm.

[0003] In the '115 patent, the inventors recognized in Figures 15 and 25 therein and in the accompanying disclosure that deficiencies would arise when implementing the above-described techniques. (See col. 3, lines 31-40; col. 4, lines 1-10 of the '115 patent; and Figures 1 and 2 herein.) However, the present inventors have found that, as shown in FIG. 15 , in a pre-cutting process in which the insertion position of the pre-cutting blade C is set deep, the tacky-adhesive layer 12 in the adhesive sheet obtained is caught in the incision E in the release substrate 10, and the interface between the release substrate 10 and the tacky-adhesive layer 12 is sealed. Furthermore, the present inventors have found that if the adhesive sheet is laminated onto a wafer while maintaining this state, the tacky-adhesive layer 12 becomes difficult to peel from the release substrate 10, and peeling defects are likely to occur. *** However, the present inventors have found that, as shown in FIG. 25 , in an adhesive sheet obtained by pre-cutting in which the insertion position of the pre-cut blade C is set deep, the adhesive layer 214 and the pressure-sensitive adhesive layer 222 become caught in the notch F in the release substrate 212, sealing the interface between the release substrate 212 and the adhesive layer 214. Furthermore, the present inventors have found that if the adhesive sheet is laminated onto a wafer while maintaining this state, the adhesive layer 214 becomes difficult to peel from the release substrate 212, and peeling defects are likely to occur.

[0004] U.S. Patent No. 8,465,615 (Tanaka) describes a method for manufacturing a semiconductor wafer having a stack of layers, a step of peeling off the release substrate from an adhesive sheet comprising a release substrate, a base film, and a tacky-adhesive layer disposed between the release substrate and the base film to obtain a laminate comprising the base film and the tacky-adhesive layer; and A step of attaching the adhesive layer of the laminate to a semiconductor wafer Including, a release substrate of the adhesive sheet has an annular notch formed in the release substrate from the adhesive layer side of the release substrate; The thickness of the release substrate is 30 to 50 μm, The adhesive layer covers the entire inner surface of the notch of the release substrate, The depth of the cut is greater than 0 μm and less than 25 μm; and The method of laminating the stack onto the semiconductor wafer is carried out in a series of automated steps, and this is what is claimed.

[0005] The relevant drawings and disclosures of the '155 patent are present in the '615 patent as well.

[0006] Unlike the disclosures of the two cited methods above, in which cuts are formed in the adhesive sheet during processing and, in some cases, an irradiation step is introduced, there remains a need for a manufacturing process for producing such adhesive sheets that is more reproducible and has fewer defective parts. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 8,470,115 [Patent Document 2] U.S. Patent No. 8,465,615 Summary of the Invention [Means for solving the problem]

[0008] That need has been met herein.

[0009] In one embodiment, the present specification provides a method for producing a die-attach adhesive film sheet, the method comprising the following steps: A. providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and bonding the first release substrate layer, the die attach adhesive layer, and the dicing tape layer in this order to form a multilayer structure; B. processing the multilayer structure to form a circular preformed die attach adhesive film sheet, wherein during said processing, a Z-direction indentation is formed in the first release substrate; and C. removing the first release substrate having the Z-direction indentation from the die attach adhesive layer and replacing it with a second release substrate in contact with the die attach adhesive layer. Includes.

[0010] In another aspect herein, there is provided a method for manufacturing a semiconductor chip, the method comprising the steps of: A1. Providing a die attach adhesive film sheet manufactured by a method having the steps described as A to C in the preceding paragraph; B1. Peeling the second release substrate from the die-attach adhesive film sheet to expose the die-attach adhesive film layer; and C1. A step of providing a semiconductor wafer having an adhesive surface, and bonding the adhesive surface of the semiconductor wafer to the die-attach adhesive film sheet via the die-attach adhesive layer. Includes. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows FIG. 15 of US Pat. No. 8,470,115 (Tanaka) as an illustration of the problem to which this disclosure provides a solution. [Figure 2] FIG. 2 shows FIG. 25 of US Pat. No. 8,470,115 (Tanaka) as an illustration of the problem to which the present disclosure provides a solution. [Figure 3] FIG. 3 shows a schematic diagram of the method described by the present disclosure in a two-phase configuration. [Figure 4] FIG. 4 shows a schematic diagram of the method described by the present disclosure in a one-phase configuration. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Detailed explanation> As mentioned above, one embodiment provided herein is a method for producing a die-attach adhesive film sheet. The method of this embodiment includes the following steps: A. providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and bonding the first release substrate layer, the die attach adhesive layer, and the dicing tape layer in that order to form a multilayer structure, such as a first multilayer structure or a first format multilayer structure (i); B. processing the multilayer structure to form a circular preformed die attach adhesive film sheet, wherein during said processing, a Z-direction indentation is formed in the first release substrate, the Z-direction indentation having a first diameter; and C. Removing the first release substrate having the Z-direction indentations from the die attach adhesive layer and replacing it with a second release substrate in contact with the die attach adhesive layer to form a second multilayer structure or a multilayer structure of a second format (ii). Includes.

[0013] The additional steps are as follows: D. processing the multilayer structure (ii) to form a Z-direction indentation in the second release substrate, the Z-direction indentation having a second diameter, the second diameter being greater than the first diameter; Includes.

[0014] In some embodiments, the first release substrate is composed of polyester, optionally coated with a release agent. The polyester desirably has a tensile strength greater than 130 MPa in the machine direction (i.e., the direction in which the substrate moves through the process), a tensile strength greater than 150 MPa in the cross direction (i.e., the direction perpendicular to the direction in which the substrate moves through the process), and a modulus of elasticity of 500-600 Kpsi. When a release agent is used to coat the polyester release substrate, the release agent may be selected from a variety of materials, such as crosslinkable silicones, waxes, and fatty esters. The release agent may be liquid or solid. If liquid, it may be applied directly to the release substrate or may be diluted with a solution or dispersion and then applied to the release substrate. Commercially available examples of release substrates composed of polyester, with or without a release agent coating, include HOSTAPHAN (Mitsubishi), PRIMELINER (Loparex), and TEXCELL (Toray).

[0015] In some embodiments, the second release substrate is composed of polyester and is optionally coated with a release agent.

[0016] In some embodiments, the thickness of the first release substrate is from about 35 μm to about 50 μm.

[0017] In some embodiments, the thickness of the second release substrate is from about 35 μm to about 50 μm.

[0018] The second release substrate may be the same as or different from the first release substrate, and all of the characteristics and properties of the first release substrate also apply to the second release substrate. Thus, the first release substrate may be the same as or different from the second release substrate.

[0019] In some embodiments, the dicing tape layer is constructed from a variety of materials such as PVC, polyolefin, or polyethylene, with polyolefin being preferred.

[0020] In some embodiments, the thickness of the dicing tape layer is from about 80 microns to about 150 microns.

[0021] In some embodiments, the die-attach adhesive layer comprises a curable matrix comprising at least one of an epoxy resin; a maleimide-containing resin, a nadimide-containing resin, and / or an itaconimide-containing resin; and / or a (meth)acrylate resin.

[0022] The epoxy resin may be selected from epoxy resins based on bisphenol A, bisphenol F, or bisphenol S, multifunctional epoxy resins based on phenol novolac resins, dicyclopentadiene-type epoxy resins, naphthalene-type epoxy resins, etc. Examples of other epoxy-functionalized resins contemplated for use herein include diepoxides of cycloaliphatic alcohols, hydrogenated bisphenol A (commercially available as Epalloy 5000), difunctional cycloaliphatic glycidyl ester of hexahydrophthalic anhydride (commercially available as Epalloy 5200), Epiclon EXA-835LV, Epiclon HP-7200L, etc., and mixtures of any two or more thereof.

[0023] Commercially available examples of bisphenol epoxies contemplated for use herein include bisphenol F-type epoxies (e.g., RE-404-S manufactured by Nippon Kayaku Co., Ltd. of Japan, and EPICLON 830 (RE1801), 830S (RE1815), 830A (RE1826), and 830W manufactured by Dai Nippon Ink & Chemicals, Inc., and RSL1738 and YL-983U manufactured by Resolution), and bisphenol A-type epoxies (e.g., YL-979 and 980 manufactured by Resolution). Further examples of commercially available epoxy resins include Epon 828, Epon 826, Epon 862 (all manufactured by Hexion Corporation), DER 331, DER 383, DER 332, DER 330-EL, DER 331-EL, DER 354, DER 321, DER 324, DER 29, DER 353 (all manufactured by Dow Chemical Company), JER YX8000, JER RXE21, JER YL 6753, JER YL6800, JER YL980, JER 825, and JER 630 (all manufactured by Japan Epoxy Resins Co., Ltd.).

[0024] The bisphenol epoxies, available from Dai Nippon Co., Ltd., are promoted as liquid, undiluted epichlorohydrin-bisphenol F epoxies with much lower viscosities than conventional epoxies based on bisphenol A epoxy, and have similar physical properties to liquid bisphenol A epoxy. While the bisphenol F epoxy has a lower viscosity than the bisphenol A epoxy, the two epoxies are otherwise identical, providing a lower viscosity and therefore faster-flowing underfill sealant material. The epoxy equivalent weight (EEW), calculated by dividing the molecular weight by the number of epoxy groups, of these four bisphenol F epoxies ranges from 165 to 180. Viscosity at 25°C ranges from 3,000 to 4,500 cps (except for RE1801, whose viscosity limit is 4,000 cps). The hydrolyzable chloride content is reported to be 200 ppm for RE1815 and 830W, and 100 ppm for RE1826.

[0025] The bisphenol epoxies listed above, available from Resolution, are recommended as low-chloride liquid epoxies. Bisphenol A epoxies have an EEW (g / eq) of 180-195 and a viscosity at 25°C of 100-250 cp. YL-979 is reported to have a total chloride content of 500-700 ppm, while YL-980 is reported to have a total chloride content of 100-300 ppm. Bisphenol F epoxies have an EEW (g / eq) of 165-180 and a viscosity at 25°C of 30-60 ppm. RSL-1738 is reported to have a total chloride content of 500-700 ppm, while YL-983U is reported to have a total chloride content of 150-350 ppm.

[0026] In addition to bisphenol epoxies, other epoxy compounds are contemplated for use as the epoxy component of the formulations of the present invention. For example, cycloaliphatic epoxies such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carbonate can be used. Monofunctional, difunctional, or multifunctional reactive diluents may also be used to adjust the viscosity and / or lower the glass transition temperature (Tg) of the resulting resin material. Examples of reactive diluents include butyl glycidyl ether, cresyl glycidyl ether, o-cresyl glycidyl ether, polyethylene glycol glycidyl ether, polypropylene glycol glycidyl ether, and the like.

[0027] Other epoxies suitable for use herein include polyglycidyl derivatives of phenolic compounds, such as those commercially available under the tradename EPON, such as EPON 828, EPON 1001, EPON 1009, and EPON 1031 from Resolution; DER 331, DER 332, DER 334, and DER 542 from Dow Chemical; and BREN-S from Nippon Kayaku. Other suitable epoxies include polyepoxides prepared from polyols and polyglycidyl derivatives of phenol-formaldehyde novolac, such as DEN 431, DEN 438, and DEN 439 from Dow Chemical. Cresol analogs are also commercially available under the tradename ARALDITE, such as ARALDITE ECN 1235, ARALDITE ECN 1273, and ARALDITE ECN 1299 from Ciba Specialty Chemicals. SU-8 is a bisphenol A type epoxy novolac available from Resolution, Inc. Polyglycidyl adducts of amines, aminoalcohols, and polycarboxylic acids are also useful in the present invention, commercially available resins include GLYAMINE 135, GLYAMINE 125, and GLYAMINE 115 from FIC, ARALDITE MY-720, ARALDITE 0500, and ARALDITE 0510 from Ciba Specialty Chemicals, and PGA-X and PGA-C from Sherwin-Williams.

[0028] The epoxy resin may be in a liquid state and is heated at 25°C and a shear rate of 1 s -1 The viscosity at 25°C and a shear rate of 1 s may be 5,000 cP or less, for example. -1 The shear rate may be 2,000 cP or less at 25°C and a shear rate of 1 s -1 It may be 1,000 cP or less at 25°C and a shear rate of 1 s -1 It may be 500 cP or less.

[0029] The epoxy resin component of the curable composition may further comprise a monofunctional epoxy resin. Surprisingly, it has been discovered that such monoepoxide resins limit further changes in crosslink density and / or network properties after the onset of gelation, presumably through reaction with otherwise unreacted 2' amines and even 3' amines, thereby improving retention of cured material properties as a function of time. The monoepoxide resin may further react with available -OH groups on the epoxy backbone. Furthermore, the addition of the monoepoxide resin surprisingly results in improved thermal reliability, at least within certain loading levels, compared to other epoxy resins.

[0030] Examples of monoepoxy resins include monoglycidyl ethers such as phenyl glycidyl ether, alkylphenol monoglycidyl ether, aliphatic monoglycidyl ether, alkylphenol monoglycidyl ether, alkylphenol monoglycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and o-cresyl glycidyl ether.

[0031] Monoepoxy resins (or monofunctional epoxy resins) may have epoxy groups with alkyl groups of from about 6 to about 28 carbon atoms, examples of which include C 6-28 Alkyl glycidyl ether, C 6-28 Fatty acid glycidyl ether, C 6-28 Examples thereof include alkylphenol glycidyl ether.

[0032] The maleimide-, nadimide-, and / or itaconimide-containing resin may be selected from a variety of materials.

[0033] In certain embodiments, the degree of substitution of imide moieties on the first maleimide, nadimide, or itaconimide backbone is at least 0.8 imide moieties, such as at least 1 imide moiety, per repeat unit of the backbone.

[0034] In certain embodiments, the maleimide, nadimide, or itaconimide has the following structure:

[0035] [ka] (wherein, m is 1 to 15; p is 0 to 15, Each R 2 is independently selected from hydrogen or lower alkyl, and J is a monovalent or polyvalent group selected from: an aromatic hydrocarbyl or substituted aromatic hydrocarbyl species having in the range of from about 6 to about 300 carbon atoms, wherein the aromatic hydrocarbyl species is selected from aryl, alkylaryl, arylalkyl, arylalkenyl, alkenylaryl, arylalkynyl, or alkynylaryl; an aromatic hydrocarbylene or substituted aromatic hydrocarbylene species having in the range of from about 6 to about 300 carbon atoms, wherein the aromatic hydrocarbyl species is selected from arylene, alkylarylene, arylalkylene, arylalkenylene, alkenylarylene, arylalkynylene, or alkynylarylene; heterocyclic or substituted heterocyclic species having from about 6 to about 300 carbon atoms; polysiloxane, or polysiloxane-polyurethane block copolymers, and One or more of the above, Covalent bond, -O-,-S-,-NR-,-NR-C(O)-,-NR-C(O)-O-,-NR-C(O)-NR-,-SC(O)-,-SC(O)-O-,-SC(O)- NR-,-OS(O)2-,-OS(O)2-O-,-OS(O)2-NR-,-OS(O)-,-OS(O)-O-,-OS(O)-NR-,-O-NR-C(O)-,-O -NR-C(O)-O-,-O-NR-C(O)-NR,-NR-OC(O)-,-NR-OC(O)-O-,-NR-OC(O)-NR-,-O-NR-C(S)-,-O -NR-C(S)-O-,-O-NR-C(S)-NR-,-NR-OC(S)-,-NR-OC(S)-O-,-NR-OC(S)-NR-,-OC(S)-,-OC(S) -O-,-OC(S)-NR-,-NR-C(S)-,-NR-C(S)-O-,-NR-C(S)-NR-,-SS(O)2-,-SS(O)2-O-,-SS(O)2- NR-,-NR-OS(O)-,-NR-OS(O)-O-,-NR-OS(O)-NR-,-NR-OS(O)2-,-NR-OS(O)2-O-,-NR-OS(O)2- NR-, -O-NR-S(O)-, -O-NR-S(O)-O-, -O-NR-S(O)-NR-, -O-NR-S(O)-O-, -O-NR-S(O)-NR-, -O-NR-S(O)-, -O-P(O)R-, -SP(O)R-, or -NR-P(O)R- (wherein each R is independently hydrogen, alkyl, or substituted alkyl). In combination with a linker selected from:

[0036] In some embodiments of the invention, J of the maleimide, nadimide, or itaconimide is selected from the group consisting of heterocyclic, oxyheterocyclic, thioheterocyclic, aminoheterocyclic, carboxyheterocyclic, oxyaryl, thioaryl, aminoaryl, carboxyaryl, heteroaryl, oxyheteroaryl, thioheteroaryl, aminoheteroaryl, carboxyheteroaryl, oxyalkylaryl, thioalkylaryl, aminoalkylaryl, carboxyalkylaryl, oxyarylalkyl, thioarylalkyl, aminoarylalkyl, carboxyarylalkyl, oxyarylalkenyl, thioarylalkenyl, aminoarylalkenyl, carboxyarylalkenyl, oxyalkenylaryl, thioalkenylaryl, aminoalkenylaryl, carboxyalkenylaryl, oxyarylalkynyl, thioarylalkynyl, aminoarylalkynyl, carboxyarylalkynyl, oxyalkynylaryl, thioalkynylaryl, aminoalkynylaryl, or kaolin. carboxyalkynylaryl, oxyarylene, thioarylene, aminoarylene, carboxyarylene, oxyalkylarylene, thioalkylarylene, aminoalkylarylene, carboxyalkylarylene, oxyarylalkylene, thioarylalkylene, aminoarylalkylene, carboxyarylalkylene, oxyarylalkenylene, thioarylalkenylene, aminoarylalkenylene, carboxyarylalkenylene, oxyalkenylarylene, thioalkenylarylene, aminoaryl alkynylarylene, carboxyalkenylarylene, oxyarylalkynylene, thioarylalkynylene, aminoarylalkynylene, carboxyarylalkynylene, oxyalkynylarylene, thioalkynylarylene, aminoalkynylarylene, carboxyalkynylarylene, heteroarylene, oxyheteroarylene, thioheteroarylene, aminoheteroarylene, carboxyheteroarylene, heteroatom-containing divalent or polyvalent cyclic partial structure, oxyheteroatom-containing divalent or polyvalent cyclic partial structure,a thioheteroatom-containing divalent or polyvalent cyclic moiety, an aminoheteroatom-containing divalent or polyvalent cyclic moiety, or a carboxyheteroatom-containing divalent or polyvalent cyclic moiety.

[0037] In certain embodiments, the maleimides, nadimides, or itaconimides contemplated for use herein comprise linear or branched hydrocarbyl segments, each hydrocarbyl segment having at least 30 carbon atoms, thereby facilitating its flexibility.

[0038] Examples of maleimides, nadimides or itaconimides include the following:

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] In these structures, m and n range from 0 to 10, and x and y range from 0 to 50, as appropriate.

[0043] The (meth)acrylate resin may be selected from a variety of materials including monofunctional (meth)acrylates, difunctional (meth)acrylates, trifunctional (meth)acrylates, multifunctional (meth)acrylates, and the like.

[0044] Exemplary monofunctional (meth)acrylates include, for example, H2C=CGCO2R 1 wherein G may be hydrogen, halogen, or an alkyl group having 1 to about 4 carbon atoms; R 1may be selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, aralkyl, or aryl groups having 1 to about 16 carbon atoms, any of which may optionally be substituted or interrupted by silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbonate, amine, amide, sulfur, sulfonate, sulfone, and the like. The monofunctional (meth)acrylate may be a hydroxyl-functional (meth)acrylate, such as hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate ("HEMA"), hydroxypropyl methacrylate ("HPMA"), hydroxybutyl methacrylate, and mixtures thereof. Other examples of suitable hydroxy-functional (meth)acrylates include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate (“HEMA”), pentaerythritol triacrylate (“PETA”), and 4-hydroxybutyl acrylate.

[0045] Examples of difunctional (meth)acrylates include hexanediol dimethacrylate, hydroxyacryloyloxypropyl methacrylate, hexanediol diacrylate, urethane acrylate, epoxy acrylate, bisphenol A type epoxy acrylate, modified epoxy acrylate, fatty acid modified epoxy acrylate, amine modified bisphenol A type epoxy acrylate, allyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethoxylated bisphenol A dimethacrylate, tricyclodecane dimethanol dimethacrylate, glycerin dimethacrylate, polypropylene glycol diacrylate, propoxylated ethoxylated bisphenol A diacrylate, 9,9-bis(4-(2-acryloyloxyethoxy)phenyl)fluorene, tricyclodecane diacrylate, dipropylene glycol diacrylate, polypropylene glycol diacrylate, PO-modified neopentyl glycol diacrylate, tricyclodecane dimethanol diacrylate, and 1,12-dodecanediol dimethacrylate.

[0046] Examples of trifunctional (meth)acrylates include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxy triacrylate, polyether triacrylate, and glycerin propoxy triacrylate.

[0047] Examples of polyfunctional (meth)acrylates include dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxy tetraacrylate, and ditrimethylolpropane tetraacrylate.

[0048] Additional examples of (meth)acrylates contemplated for use in the practice of the present invention include those described in US Pat. No. 5,717,034, the entire contents of which are incorporated herein by reference.

[0049] In some embodiments, the die attach adhesive layer includes one or more fillers, such as conductive fillers such as silver or copper. Commercially available examples of such conductive fillers may be selected from Metalor's EA series and Dowa's Ag-SAB silver powder series of products.

[0050] In some embodiments, the die attach adhesive layer comprises silica.

[0051] In a particularly desirable embodiment, the first release substrate layer is composed of a polyester having a machine direction tensile strength of 224 MPa, a transverse direction tensile strength of 309 MPa, and a modulus of elasticity of 538 Kpsi, and is coated with a crosslinkable silicone as a release agent; the die attach adhesive layer is composed of a matrix resin including a combination of a high molecular weight carboxyl-terminated butadiene / acrylonitrile epoxy as the epoxy resin and about 5% to about 30% by weight of BMI-1700 as the maleimide resin; and the dicing tape layer is composed of a polyolefin having a thickness of 85 microns.

[0052] The conditions for bonding the first release substrate layer, die attach adhesive layer, and dicing tape layer in this order include a rotary converter operating speed of 5 to 25 fpm, pressure settings for the cutting die and nip rolls of 50 psi to 500 psi, and a tension setting for the drive spindle of 4 lbs to 10 lbs. In the manufacturing process, an unwinding spindle releases the upstream coated bulk roll, and a first cutting die cuts the protective film and adhesive layer to form a circular adhesive film sheet. See Figures 3 and 4 herein.

[0053] In making the first cut, the first cutting die also makes a Z-direction cut in the first release substrate. This Z-direction cut has a first diameter. After the first cut is made by the first cutting die, the remaining protective liner and adhesive film layer are removed by unwinding the spindle. The dicing tape is then released from the unwinding spindle and laminated onto the adhesive film sheet, resulting in a multilayer structure including the first release substrate, the adhesive film sheet, and the dicing tape.

[0054] Next, the first release substrate, including the cut marks from the first cutting die during the cutting operation, is removed, and a second release substrate is released by an unwinding spindle and laminated onto the adhesive film sheet and dicing tape using the nip rolls of a rotary converter.

[0055] A second cutting die then cuts the dicing tape, overlapping the dicing tape circle on the adhesive film sheet, thereby forming a multilayer structure. This multilayer structure includes a second release substrate (without cut marks), an adhesive film sheet, and a dicing tape. This operation can be performed with a rotary converter operating speed of 5 to 25 fpm and a cutting die and nip roller pressure setting of 50 psi to 500 psi. The drive spindle tension can be set at 4 lbs to 10 lbs.

[0056] Another aspect provided herein is a method for manufacturing a semiconductor chip, the method comprising the steps of: A1. Providing a die attach adhesive film sheet manufactured by the method described in the preceding paragraph; B1. Peeling the second release substrate from the die-attach adhesive film sheet to expose the die-attach adhesive film layer; and C1. A step of providing a semiconductor wafer having an adhesive surface and bonding the adhesive surface of the semiconductor wafer to the die-attach adhesive film sheet via a die-attach adhesive layer. Includes.

[0057] The die-attach adhesive film sheet layer is as described above.

[0058] The second release substrate is as described above.

[0059] The semiconductor wafer may be a silicon wafer with a diameter of 8 or 12 inches and a thickness in the range of 80 microns to 200 microns. The back surface of the silicon wafer is smooth, onto which a die-attach adhesive sheet can be laminated.

[0060] In some embodiments, the method comprises the steps of: D1. A step of dicing a semiconductor wafer having a die-attach adhesive film bonded to a surface of the semiconductor wafer to obtain a semiconductor element having a die-attach adhesive film of a predetermined size that can be used for further bonding. Further includes:

[0061] The semiconductor wafer onto which the die attach adhesive film is placed may have dimensions ranging from 2x2 millimeters to 8x8 millimeters to obtain a semiconductor device.

[0062] Semiconductor devices (or semiconductor dies) are separated from a wafer using a dicing process, which involves scribing a wafer with a predetermined pattern and separating the scribed wafer into individual dies (e.g., by mechanical cutting using a dicing saw or by laser cutting). Dicing saws typically use rotational speeds of 15,000 to 30,000 rpm.

[0063] In some embodiments, the method comprises the steps of: E1. Attaching a semiconductor device with the die-attach adhesive layer exposed for bonding to a carrier substrate via the die-attach adhesive layer to form a semiconductor package or semiconductor assembly. Further includes:

[0064] Semiconductor packages or assemblies are typically used in quad flat no-lead packages (or QFN) or thin quad flat no-lead packages (or TQFN). These packages are leadless and small, while providing adequate heat dissipation within the PCB. Like other IC packages, the function of the QFN package is to connect the silicon die of the IC to a circuit board.

[0065] The die attach (adhesion) curing conditions are as follows: heat from 25°C to 200°C in 30 minutes, then hold at 200°C for 60 minutes, or heat from 25°C to 175°C in 30 minutes, then hold at 175°C for 60 minutes.

[0066] When using known wafer lamination techniques, a failure rate as high as 50% has been reported. In fact, referring to Figures 1 and 2 of the present specification, which illustrate the technique described in U.S. Pat. No. 8,470,115 (Tanaka) (shown in Figures 15 and 25 and their supplementary descriptions), the initial notch formed in the release substrate prevented the adhesive layer from being completely laminated to the backside of the wafer. More specifically, the adhesive sheet may tear during the wafer lamination process, in which case part of the adhesive sheet may remain on the release substrate, resulting in failure during the wafer lamination process of the adhesive sheet. Under certain lamination conditions (e.g., a lamination speed of 10 mm / s or less), the failure rate may be as high as 50%.

[0067] In contrast, the method of the present invention described and claimed herein significantly reduces the defect rate. More specifically, referring to Figures 3 and 4, by replacing the first release substrate with a second release substrate that does not include a notch, a defect rate as low as 0% can be achieved under the same wafer lamination conditions. In fact, 320 sheets made by this method were evaluated under lamination conditions of 10 mm / s or less, and no defects were observed.

Claims

1. 1. A method for producing a die attach adhesive film sheet, comprising: A. Providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and bonding the first release substrate layer, the die attach adhesive layer, and the dicing tape layer in this order to form a multilayer structure (i); B. processing the multilayer structure (i) to form a circular preformed die attach adhesive film sheet, wherein during said processing a Z-direction indentation is formed in the first release substrate, the Z-direction indentation having a first diameter; and C. Removing the first release substrate having the Z-direction indentations from the die attach adhesive layer and replacing it with a second release substrate in contact with the die attach adhesive layer to form multi-layer structure (ii). A method comprising:

2. moreover, D. Processing the multilayer structure (ii) to form a Z-direction indentation in the second release substrate, the Z-direction indentation having a second diameter, the second diameter being greater than the first diameter. The method of claim 1 , comprising:

3. The method of claim 1 , wherein the first release substrate is comprised of polyester and is optionally coated with a release agent.

4. The method of claim 1 , wherein the second release substrate is comprised of polyester and is optionally coated with a release agent.

5. The method of claim 1, wherein the first release substrate has a thickness of about 35 μm to about 50 μm.

6. The method of claim 1, wherein the second release substrate has a thickness of about 35 μm to about 50 μm.

7. The method of claim 1 , wherein the dicing tape layer is composed of PVC, polyolefin, or polyethylene.

8. The method of claim 1, wherein the dicing tape layer has a thickness of about 80 microns to about 150 microns.

9. 10. The method of claim 1, wherein the die-attach adhesive layer comprises a curable matrix comprising at least one of an epoxy resin; a maleimide-containing resin, a nadimide-containing resin, and / or an itaconimide-containing resin; and / or a (meth)acrylate resin.

10. The method of claim 1 , wherein the die attach adhesive layer comprises one or more fillers.

11. The method of claim 1 , wherein the die attach adhesive layer comprises silica.

12. The method of claim 1 , wherein the die attach adhesive layer comprises a conductive filler.

13. The method of claim 1 , wherein the die attach adhesive layer comprises silver.

14. 1. A method for manufacturing a semiconductor chip, comprising: A1. Providing a die attach adhesive film sheet produced by the method of claim 1 or 2; B1. Peeling the second release substrate from the die-attach adhesive film sheet to expose the die-attach adhesive film layer; and C1. A step of providing a semiconductor wafer having an adhesive surface, and bonding the adhesive surface of the semiconductor wafer to the die-attach adhesive film sheet via the die-attach adhesive layer. A method comprising:

15. moreover, D1. A step of dicing the semiconductor wafer having the die-attach adhesive film bonded to the surface of the semiconductor wafer to obtain a semiconductor element having a die-attach adhesive film of a predetermined size that can be used for further bonding.

15. The method of claim 14, comprising:

16. moreover, E1. Attaching a semiconductor device with the die-attach adhesive layer exposed for bonding to a carrier substrate via the die-attach adhesive layer to form a semiconductor package or semiconductor assembly.

16. The method of claim 15, comprising:

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