Method for producing die-bonding adhesive film sheet

Abstract

Provided herein is a method for manufacturing a die bonding adhesive film sheet, the method comprising: providing a first release substrate layer, a die bonding adhesive layer, and a dicing tape layer, and sequentially connecting the first release substrate layer, the die bonding adhesive layer, and the dicing tape layer together to form a multi-layer structure; processing the multi-layer structure to form a circular preformed die bond adhesive film sheet, wherein the first release substrate is subjected to a z-direction indentation therein during the processing; and removing the first release substrate with the z-direction indentation from the die bonding adhesive layer, and alternatively placing a second release substrate in contact with the die bonding adhesive layer.

Description

Technical Field

[0001] A method for making a die attach adhesive film sheet is provided herein. Background Art

[0002] US Patent No. 8,470,115 (Tanaka) relates to and claims a method for manufacturing a semiconductor device, the method comprising:

[0003] peeling a laminate including an adhesive layer, a tack layer and a substrate film in an adhesive sheet from a release substrate of the adhesive sheet, the adhesive sheet comprising a release substrate, an adhesive layer, a tack layer and a substrate film laminated in sequence, and adhering the laminate to a semiconductor wafer through the adhesive layer to obtain a semiconductor wafer having the laminate;

[0004] cutting the semiconductor wafer having the laminate to obtain semiconductor elements having the laminate of a predetermined size;

[0005] irradiating the tacky layer with a high-energy light beam to reduce the adhesion strength between the tacky layer and the adhesive layer, and then peeling the tacky layer and the base film from the adhesive layer to obtain a semiconductor element having the adhesive layer; and

[0006] bonding a semiconductor element having an adhesive layer to a supporting member for mounting the semiconductor element through the adhesive layer, wherein the adhesive layer has a predetermined first planar shape and is formed on a portion of a release substrate;

[0007] wherein a first incision is formed in the release substrate from a side in contact with the adhesive layer along the periphery of the plane shape of the adhesive layer;

[0008] wherein the release substrate has a thickness of 30 to 50 μm; and

[0009] The first cutout has a depth greater than zero and less than 25 μm.

[0010] In the '115 patent, the named inventors recognized in FIGS. 15 and 25 therein and the accompanying disclosure that deficiencies may occur in practicing the techniques so discussed. (See the '115 patent, col. 3, lines 31-40; col. 4, lines 1-10; herein Figure 1 and 2 . )

[0011] However, the inventors of the present invention have found that, as shown in FIG15 , the tacky-adhesive layer 12 in the adhesive sheet obtained in the pre-cutting process in which the insertion position of the pre-cutting blade C is set to be deep is bitten by the cutout E in the release substrate 10, and the interface between the release substrate 10 and the tacky-adhesive layer 12 is sealed. The inventors of the present invention have also found that when the adhesive sheet is laminated on a wafer while maintaining this state, it is difficult to peel the tacky-adhesive layer 12 from the release substrate 10, and peeling defects are likely to occur.

[0012] ***

[0013] However, the inventors of the present invention have found that, as shown in Fig. 25, the adhesive layer 214 and the tack layer 222 in the adhesive sheet obtained in the pre-cutting process in which the insertion position of the pre-cutting blade C is set to be deep are bitten by the cutout F in the release substrate 212, and the interface between the release substrate 212 and the adhesive layer 214 is sealed. The inventors of the present invention have also found that when the adhesive sheet is laminated on a wafer while maintaining this state, it is difficult to peel the adhesive layer 214 from the release substrate 212, and peeling defects are likely to occur.

[0014] US Patent No. 8,465,615 (Tanaka) relates to and claims a method for making a semiconductor wafer having a laminate, the method comprising:

[0015] peeling a release substrate from an adhesive sheet comprising a release substrate, a substrate film, and a tacky-adhesive layer disposed between the release substrate and the substrate film to obtain a laminate comprising the substrate film and the tacky-adhesive layer; and

[0016] adhering the tacky-adhesive layer of the laminate to a semiconductor wafer,

[0017] in:

[0018] forming a circular cut in the release substrate of the adhesive sheet from the tacky-adhesive layer side of the release substrate,

[0019] The release substrate has a thickness of 30 to 50 μm,

[0020] The tacky-adhesive layer covers the entire inner surface of the cutout in the release substrate,

[0021] The cutout has a depth greater than zero and less than 25 μm, and

[0022] The lamination of the laminate to the semiconductor wafer is carried out continuously by automated steps.

[0023] The relevant drawings and disclosure of the '155 patent are also present in the '615 patent.

[0024] Unlike the disclosures in the two previously described methods, in which cuts are formed in the adhesive sheet during processing and in one case a radiation step is introduced, there is still a need for a manufacturing method for producing such an adhesive sheet that has higher reproducibility and fewer defective parts. Summary of the invention

[0025] This need is met here.

[0026] In one aspect, the present invention provides a method for making a die attach adhesive film sheet. In the method of this aspect, the steps include:

[0027] A. providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and sequentially connecting the first release substrate layer, the die attach adhesive layer, and the dicing tape layer together to form a multilayer structure;

[0028] B. processing the multilayer structure to form a circular preformed die attach adhesive film sheet, wherein the first release substrate receives a z-direction indentation therein during the processing; and

[0029] C. Removing the first release substrate having the z-direction indentation therein from the die attach adhesive layer and replacing it by placing a second release substrate in contact with the die attach adhesive layer.

[0030] In another aspect, the present invention provides a method for manufacturing a semiconductor chip. In the method of this aspect, the steps include:

[0031] A1. A die attach adhesive film sheet is provided by the method as described in the preceding numbered paragraphs A to C;

[0032] B1. peeling the second release substrate from the die attach adhesive film sheet to expose the die attach adhesive film layer; and

[0033] C1. Providing a semiconductor wafer having a bondable surface, and mating the bondable surface of the semiconductor wafer with a die attach adhesive film sheet via its die attach adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 FIG. 15 of US Patent No. 8,470,115 (Tanaka) is depicted to illustrate the problem to which the solution provided by the present disclosure is addressed.

[0035] Figure 2FIG. 25 of US Patent No. 8,470,115 (Tanaka) is depicted to illustrate the problem to which the solution provided by the present disclosure is addressed.

[0036] Figure 3 A schematic diagram depicting a two-stage configuration of the method described in the present disclosure is shown.

[0037] Figure 4 A schematic diagram depicting a single-stage configuration of the method described in the present disclosure is shown. DETAILED DESCRIPTION

[0038] As described above, in one aspect, the present invention provides a method for making a die attach adhesive film sheet. In the method of this aspect, the steps include:

[0039] A. providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and sequentially connecting the first release substrate layer, the die attach adhesive layer, and the dicing tape layer together to form a multilayer structure, such as a first multilayer structure or a first form of multilayer structure (i);

[0040] B. processing the multilayer structure to form a circular preformed die attach adhesive film sheet, wherein the first release substrate receives a z-direction indentation therein during the processing, wherein the z-direction indentation has a first diameter; and

[0041] C. Removing the first release substrate having the z-direction indentation therein from the die attach adhesive layer and replacing it by placing a second release substrate in contact with the die attach adhesive layer to form a second multilayer structure or a second form of multilayer structure (ii).

[0042] Additional steps include:

[0043] D. processing the multi-layer structure (ii) to receive a z-direction indentation in the second release substrate, wherein the z-direction indentation has a second diameter, wherein the second diameter is greater than the first diameter.

[0044] In some embodiments, the first release substrate is made of polyester, which is optionally coated with a release agent. Polyester should have a longitudinal tensile strength greater than 130MPa (i.e., the direction in which the substrate advances during processing) and a transverse tensile strength greater than 150MPa (i.e., the direction perpendicular to the direction in which the substrate advances during processing), and a modulus of 500 to 600Kpsi. When a release agent is used to coat the polyester release substrate, the release agent can be selected from a variety of materials, such as cross-linkable silicones, waxes and fatty acid esters. The release agent can be in liquid or solid form. When it is in liquid form, it can be directly applied to the release substrate, or it can be first diluted in a solution or dispersion and then applied to the release substrate. Commercially available examples of release substrates made of polyester coated with a release agent or not coated with a release agent include HOSTAPHAN from Mitsubishi, PRIMELINER from Loparex and TEXCELL from Toray.

[0045] In some embodiments, the second release substrate is made of polyester, which is optionally coated with a release agent.

[0046] In some embodiments, the first release substrate has a thickness of about 35 μm to about 50 μm.

[0047] In some embodiments, the second release substrate has a thickness of about 35 μm to about 50 μm.

[0048] The second release substrate can be the same as or different from the first release substrate. All properties and features of the first release substrate also apply to the second release substrate. Moreover, for this purpose, the first release substrate can be the same as or different from the second release substrate.

[0049] In some embodiments, the cutting tape layer is made of a variety of materials such as PVC, polyolefins, or polyethylene, desirably polyolefins.

[0050] In some embodiments, the dicing tape layer has a thickness of about 80 μm to about 150 μm.

[0051] In some embodiments, the die attach adhesive layer comprises a curable matrix comprising at least one of: an epoxy resin; a maleimide-containing, nadimide-containing and / or itaconimide-containing resin; and / or a (meth)acrylate resin.

[0052] 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. Other example epoxy functional resins contemplated for use herein include diepoxides of cycloaliphatic alcohols, hydrogenated bisphenol A (commercially available as Epalloy 5000), difunctional cycloaliphatic glycidyl esters of hexahydrophthalic anhydride (commercially available as Epalloy 5200), Epiclon EXA-835LV, Epiclon HP-7200L, etc., and mixtures of any two or more thereof.

[0053] Commercially available examples of bisphenol epoxy resins contemplated for use herein include bisphenol-F type epoxy resins (e.g., RE-404-S from Nippon Kayaku, Japan, and EPICLON 830 (RE1801), 830S (RE1815), 830A (RE1826), and 830W from Dai Nippon Ink & Chemicals, Inc., and RSL1738 and YL-983U from Resolution) and bisphenol-A type epoxy resins (e.g., YL-979 and 980 from Resolution). Other examples of commercially available epoxy resins include: Epon 828, Epon 826, Epon 862 (all from Hexion Co., Ltd.), DER 331, DER 383, DER 332, DER 330-EL, DER 331-EL, DER 354, DER 321, DER 324, DER 29, DER 353 (all from Dow Chemical Co.), JER YX8000, JER RXE21, JER YL 6753, JER YL6800, JER YL980, JER 825 and JER 630 (all from Japan Epoxy Resins Co.).

[0054] The bisphenol epoxy resins commercially available from Dai Nippon and mentioned above are promoted as liquid undiluted epichlorohydrin-bisphenol F epoxy resins having a much lower viscosity than conventional epoxy resins based on bisphenol A epoxy resins, and have similar physical properties to liquid bisphenol A epoxy resins. Bisphenol F epoxy resins have lower viscosity than bisphenol A epoxy resins; all else being equal between the two types of epoxy resins, they provide lower viscosity and therefore fast-flowing underfill encapsulant materials. The epoxy equivalent weight (EEW), which is the molecular weight of these four bisphenol F epoxy resins divided by the number of epoxy groups, is 165 to 180. The viscosity at 25°C is 3000 to 4500 cps (except RE1801, which has an upper viscosity limit of 4000 cps). The hydrolyzable chloride content of RE1815 and 830W is reported as 200 ppm, and the hydrolyzable chloride content of RE 1826 is reported as 100 ppm.

[0055] The bisphenol epoxy resins commercially available from Resolution and mentioned above are promoted as liquid epoxy resins containing low chlorides. Bisphenol A epoxy resin has an EEW (g / eq) of 180 to 195 and a viscosity at 25°C of 100 to 250 cP. The total chloride content of YL-979 is reported as 500 to 700 ppm, and the total chloride content of YL-980 is reported as 100 to 300 ppm. Bisphenol F epoxy resin has an EEW (g / eq) of 165 to 180 and a viscosity at 25°C of 30 to 60. The total chloride content of RSL-1738 is reported as 500 to 700 ppm, and the total chloride content of YL-983U is reported as 150 to 350 ppm.

[0056] In addition to bisphenol epoxy resins, other epoxy compounds are also considered to be used as the epoxy component of the formulation of the present invention. For example, alicyclic epoxy resins such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carbonate can be used. Monofunctional, difunctional or multifunctional reactive diluents can also be used to adjust the viscosity of the resulting resin material and / or reduce its glass transition temperature (Tg). Exemplary reactive diluents include butyl glycidyl ether, cresyl glycidyl ether, o-cresyl glycidyl ether, polyethylene glycol glycidyl ether, polypropylene glycol glycidyl ether, etc.

[0057] Other epoxy resins suitable for use herein include polyglycidyl derivatives of phenolic compounds, such as those commercially available from Resolution under the trade name EPON (e.g., EPON 828, EPON 1001, EPON 1009, and EPON 1031); those commercially available from Dow Chemical Co. under the trade name DER 331, DER 332, DER 334, and DER 542; and those commercially available from Nippon Kayaku under the trade name BREN-S. Other suitable epoxy resins include polyepoxides prepared from polyols and the like, and polyglycidyl derivatives of phenol-formaldehyde novolac resins, such as DEN 431, DEN 438, and DEN 439 from Dow Chemical. Cresol analogs are also commercially available from Ciba Specialty Chemicals Corporation under the trade name ARALDITE (e.g., ARALDITE ECN 1235, ARALDITE ECN 1273, and ARALDITE ECN 1299). SU-8 is a bisphenol-A type epoxy novolac resin available from Resolution. Polyglycidyl adducts of amines, amino alcohols, and polycarboxylic acids may also be used in the present invention, commercially available resins of which include: GLYAMINE 135, GLYAMINE 125, and GLYAMINE 115 from FIC Corporation; ARALDITE MY-720, ARALDITE 0500, and ARALDITE 0510 from Ciba Specialty Chemicals; and PGA-X and PGA-C from Sherwin-Williams Co.

[0058] The epoxy resin can be in liquid state and can be heated to 25°C for 1 second. -1 The viscosity is not more than 5000 cP at a shear rate of, for example, at 25°C and 1 s -1 The viscosity is not more than 2000 cP at a shear rate of 25°C and 1 s -1 The viscosity of the present invention is not more than 1000 cP at a shear rate of 1 s and more preferably at 25°C and 1 s -1 The viscosity of the composite material is no greater than 500 cP at a shear rate of .

[0059] The epoxy resin component of curable composition can further comprise monofunctional epoxy resin.Surprisingly found that this monoepoxide resin causes the time-varying maintenance of cured material characteristics to be improved, which may be due to reacting with originally unreacted 2 ' and even 3 ' amines and limiting the further change of crosslinking density and / or network characteristics after gelation begins.Monoepoxide resin can further react with available-OH groups on epoxy backbone.In addition, surprisingly observed that, by adding monoepoxide resin, thermal reliability is improved, at least in certain loading concentrations relative to other epoxy resins.

[0060] Examples of the monoepoxy resin include monoglycidyl ethers such as phenyl glycidyl ether, alkylphenol monoglycidyl ether, aliphatic monoglycidyl ether, alkylphenol monoglycidyl ether, alkylphenol monoglycidyl ether, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane and o-tolyl glycidyl ether.

[0061] The monoepoxy resin (or monofunctional epoxy resin) may have an epoxy group containing an alkyl group of 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 Alkylphenol glycidyl ether, etc.

[0062] The maleimide-containing, nadicimide-containing and / or itaconimide-containing resin may be selected from a variety of materials.

[0063] In certain embodiments, the degree of substitution of imide moieties on the backbone of the first maleimide, nadic imide, or itaconimide is at least 0.8, such as at least 1, imide moiety per repeating unit of the backbone.

[0064] In certain embodiments, the maleimide, nadic imide, or itaconimide has the structure:

[0065]

[0066] in:

[0067] m is 1 to 15,

[0068] p is 0 to 15,

[0069] Each R 2 are independently selected from hydrogen or lower alkyl, and

[0070] J is a monovalent or multivalent group selected from the following:

[0071] - an aromatic hydrocarbon group or a substituted aromatic hydrocarbon group species having in the range of about 6 to about 300 carbon atoms, wherein the aromatic hydrocarbon group species is selected from aryl, alkaryl, aralkyl, aralkenyl, alkenaryl, aralkynyl or alkynaryl;

[0072] an aromatic hydrocarbylene or substituted aromatic hydrocarbylene species having carbon atoms in the range of about 6 to about 300, wherein the aromatic hydrocarbylene species is selected from arylene, alkylarylene, arylalkylene, arylalkenylene, alkenylarylene, arylalkynylene or alkynylarylene,

[0073] - heterocyclic or substituted heterocyclic species having in the range of about 6 to about 300 carbon atoms,

[0074] - polysiloxane, or

[0075] - polysiloxane-polyurethane block copolymers, and

[0076] A combination of one or more of the above with a linker selected from the following: 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) 2 -O-、-O-NR-S(O) 2 -NR-、-O-NR-S(O) 2 -、-OP(O)R 2 -、-SP(O)R 2 -or-NR-P(O)R 2 -; wherein each R is independently hydrogen, alkyl or substituted alkyl.

[0077] In some embodiments of the present invention, J of the maleimide, nadic imide or itaconimide described above is heterocyclic, oxygen heterocyclic, thioheterocyclic, aminoheterocyclic, carboxyheterocyclic, oxyaryl, thioaryl, aminoaryl, carboxyaryl, heteroaryl, oxygen heteroaryl, thioheteroaryl, aminoheteroaryl, carboxyheteroaryl, oxyalkylaryl, thioalkylaryl, aminoalkylaryl, carboxyalkylaryl, oxyalkylalkyl, thioalkylalkyl, aminoaralkyl, carboxyaralkyl, oxyarylalkenyl, thioarylalkenyl, aminoarylalkenyl, carboxyarylalkenyl, oxyalkenylaryl, thioalkenylaryl, aminoalkenylaryl, carboxyalkenylaryl, oxyarylalkynyl, thioarylalkynyl, aminoarylalkynyl, carboxyarylalkynyl, oxyalkynylaryl, thioalkynylaryl, aminoalkynylaryl or carboxyalkynylaryl, oxyarylene, thioarylene, aminoarylene, carboxyarylene, oxyalkyl arylene, thioalkylarylene, aminoalkylarylene, carboxyalkylarylene, oxyarylalkylene, thioarylalkylene, aminoarylalkylene, carboxyarylalkylene, oxyarylalkenylene, thioarylalkenylene, aminoarylalkenylene, carboxyarylalkenylene, oxyalkenylarylene, thioalkenylarylene, aminoalkenylarylene, carboxyalkenylarylene, oxyarylalkynylene, thioarylalkynylene, aminoarylalkynylene, carboxy Arylalkynylene, oxyalkynylarylene, thioalkynylarylene, aminoalkynylarylene, carboxyalkynylarylene, heteroarylene, oxyheteroarylene, thioheteroarylene, aminoheteroarylene, carboxyheteroarylene, a di- or multivalent cyclic moiety containing a heteroatom, a di- or multivalent cyclic moiety containing an oxygen heteroatom, a di- or multivalent cyclic moiety containing a sulfur heteroatom, a di- or multivalent cyclic moiety containing an amino heteroatom, or a di- or multivalent cyclic moiety containing a carboxyl heteroatom.

[0078] In certain embodiments, the backbone of the maleimide, nadic imide, or itaconimide contemplated for use herein comprises linear or branched hydrocarbyl segments, wherein each hydrocarbyl segment has at least 30 carbons, thereby enhancing its flexibility.

[0079] Examples of maleimide, nadic imide or itaconimide include:

[0080]

[0081]

[0082]

[0083] In these structures, m and n are in the range of 0 to 10, and x and y are in the range of 0 to 50, as appropriate.

[0084] The (meth)acrylate resin may be selected from various materials including monofunctional (meth)acrylate, difunctional (meth)acrylate, trifunctional (meth)acrylate, multifunctional (meth)acrylate, and the like.

[0085] Exemplary monofunctional (meth)acrylates include those selected from a wide variety of materials, such as those composed of H 2 C=CGCO 2 R 1 those represented by, wherein G may be hydrogen, halogen or an alkyl group having 1 to about 4 carbon atoms, and wherein R 1 The monofunctional (meth)acrylate may be selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, aralkyl or aryl groups having from 1 to about 16 carbon atoms, any of which may be optionally substituted or interrupted, as appropriate, by silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, carbamate, carbonate, amine, amide, sulfur, sulfonate, sulfone, etc. The monofunctional (meth)acrylate may also be a hydroxy-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.

[0086] Exemplary difunctional (meth)acrylates include hexanediol dimethacrylate, hydroxyacryloxypropyl 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, glycerol 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, 1,12-dodecanediol dimethacrylate, and the like.

[0087] Exemplary trifunctional (meth)acrylates include trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxy triacrylate, polyether triacrylate, glycerol propoxy triacrylate, and the like.

[0088] Exemplary multifunctional (meth)acrylates include dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxy tetraacrylate, di(trimethylolpropane) tetraacrylate, and the like.

[0089] Additional exemplary (meth)acrylates contemplated for use in the practice of the present invention include those described in US Patent No. 5,717,034, the entire contents of which are hereby incorporated by reference.

[0090] In some embodiments, the die attach adhesive layer includes one or more fillers, such as conductive fillers, such as silver or copper. Examples of commercially available options for such conductive fillers can be selected from the EA series products from Metalor and the Ag-SAB silver powder series products from Dowa.

[0091] In some embodiments, the die attach adhesive layer comprises silicon dioxide.

[0092] In a particularly desired embodiment, the first release substrate layer is made of polyester having a longitudinal tensile strength of 224 MPa and a transverse tensile strength of 309 MPa, and a modulus of 538 Kpsi, and having a coating of a cross-linkable silicone as a release agent; the die attach adhesive layer is made of a matrix resin comprising a combination of a high molecular weight carboxyl-terminated butadiene / acrylonitrile epoxy resin as an epoxy resin and BMI-1700 as a maleimide resin in a weight ratio of about 5% to about 30%; and the dicing tape layer is made of a polyolefin and has a thickness of 85 microns.

[0093] The conditions for sequentially joining the first release substrate layer, the die attach adhesive layer, and the dicing tape layer together include: a rotary converter operating speed of 5 to 25 fpm, a cutting die and nip rolls pressure set point of 50 psi to 500 psi, and a driven spindle tension set point of 4 lbs to 10 lbs. During the manufacturing process, the unwinding spindle releases the upstream coated bulk roll, and the first cutting die cuts the protective film and adhesive layer to form a circular adhesive film sheet. See the Figure 3 and 4 .

[0094] When performing 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 performed by the first cutting die, the remaining protective liner and adhesive film layer are removed by rewinding the shaft. Then, the cutting tape is released from the unwinding shaft and laminated on the adhesive film sheet to form a multilayer structure comprising the first release substrate, the adhesive film sheet and the cutting tape.

[0095] Then, the first release substrate including the cut marks from the first cutting die during the cutting operation was removed, and the second release substrate was released by the unwinding shaft and laminated onto the adhesive film sheet and the cutting tape by using a pressing roller of a rotary converter.

[0096] Then, the second cutting die cuts the cutting tape to overlap with the cutting tape circle on the adhesive film sheet, thereby forming a multilayer structure. This multilayer structure includes a second release substrate (without incision marks), an adhesive film sheet and a cutting tape. This operation can be performed with a rotary converter operating speed of 5 to 25fpm and a cutting die and a pressure roller pressure setting of 50psi to 500psi. The driven shaft tension can be set at 4lbs to 10lbs.

[0097] In another aspect, the present invention provides a method for manufacturing a semiconductor chip. In the method of this aspect, the steps include:

[0098] A1. Providing a die attach adhesive film sheet manufactured by the method described in the preceding paragraph;

[0099] B1. peeling the second release substrate from the die attach adhesive film sheet to expose the die attach adhesive film layer; and

[0100] C1. Providing a semiconductor wafer having a bondable surface, and mating the bondable surface of the semiconductor wafer with a die attach adhesive film sheet via its die attach adhesive layer.

[0101] The die attach adhesive film sheet layer is as described above.

[0102] The second release substrate is as described above.

[0103] The semiconductor wafer may be an 8" or 12" inch diameter silicon wafer having a thickness of 80 microns to 200 microns. The back side of the silicon wafer is smooth, allowing a die attach adhesive sheet to be laminated thereon.

[0104] In some embodiments, the method further comprises the following steps:

[0105] D1. Dicing the semiconductor wafer with the die attach adhesive film mated to the surface of the semiconductor wafer to produce semiconductor elements with a die attach adhesive film of a predetermined size that can be used for further bonding.

[0106] The semiconductor wafer on which the die attach adhesive film is arranged may have dimensions ranging from 2×2 mm to 8×8 mm to produce a semiconductor element.

[0107] Semiconductor elements (or semiconductor chips) are separated from the wafer using a dicing process. The dicing process includes scribing the wafer in a predetermined pattern and then breaking the scribed wafer into individual chips (e.g., mechanical sawing using a dicing saw or by laser cutting). In the case of a dicing saw, a rotation speed of 15,000 to 30,000 rpm is typically used.

[0108] In some embodiments, the method further comprises the following steps:

[0109] E1. The semiconductor element having the die attach adhesive layer exposed for bonding is bonded to a carrier substrate through the die attach adhesive layer to form a semiconductor package or semiconductor assembly.

[0110] Semiconductor packages or semiconductor components are usually used in quad flat no-lead package (QFN) or thin quad flat no-lead package (TQFN). These packages are leadless and small in size while providing moderate heat dissipation in the PCB. The function of the QFN package, like any other IC package, is to connect the silicon die of the IC to the circuit board.

[0111] The die attach (bonding) curing conditions are as follows: 30 minutes from 25°C to 200°C, then hold at 200°C for 60 minutes. Alternatively, 30 minutes from 25°C to 175°C, then hold at 175°C for 60 minutes.

[0112] Using known wafer lamination techniques has reported failure rates as high as 50%. In fact, reference to this article Figure 1 and 2 (wherein the technique described in US Patent No. 8,470,115 (Tanaka) is exemplified (e.g., as shown in FIGS. 15 and 25 thereof and the supporting description therein)), the first cut formed in the release substrate causes the adhesive layer to not be fully laminated on the back side of the wafer. More specifically, during the wafer lamination process, the adhesive sheet may be torn, with portions of the adhesive sheet remaining on the release substrate, resulting in failure during the adhesive sheet wafer lamination process. Under certain lamination conditions (e.g., lamination speeds less than or equal to 10 mm / s), the failure rate may be as high as 50%.

[0113] In contrast, the inventive method described and claimed herein greatly reduces the failure rate. More specifically, reference Figure 3 and 4 , since the first release substrate was replaced by a second release substrate without the cut mark, a failure rate as low as 0% could be achieved under the same wafer lamination conditions. In fact, no defects were observed for 320 sheets manufactured in this way and evaluated under lamination conditions of less than or equal to 10 mm / s.

Claims

1. A method for producing a die attach adhesive film sheet, the method include: A. providing a first release substrate layer, a die attach adhesive layer, and a dicing tape layer, and sequentially connecting the first release substrate layer, the die attach adhesive layer, and the dicing tape layer together to form a multilayer structure (i); B. processing the multilayer structure (i) to form a circular preformed die attach adhesive film sheet, wherein the first release substrate receives a z-direction indentation therein during the processing, wherein the z-direction indentation has a first diameter; and C. Removing the first release substrate having the z-direction indentation therein from the die attach adhesive layer and replacing it by placing a second release substrate in contact with the die attach adhesive layer to form a multilayer structure (ii).

2. The method according to claim 1, further comprising: D. processing the multi-layer structure (ii) to receive a z-direction indentation in the second release substrate, wherein the z-direction indentation has a second diameter, wherein the second diameter is greater than the first diameter.

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

4. The method of claim 1, wherein the second release substrate is made of polyester, which 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 cutting tape layer is made of PVC, polyolefin or polyethylene. 8 . The method of claim 1 , wherein the dicing tape layer has a thickness of about 80 μm to about 150 μm.

9. 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, nadic imide-containing and / or 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 silicon dioxide.

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. A method for manufacturing a semiconductor chip, the method include: A1. A die bonding adhesive film sheet manufactured by the method of claim 1 or 2 is provided; B1. Peeling the second release substrate from the die bonding adhesive film sheet to expose the die bonding adhesive film layer; as well as C1. Providing a semiconductor wafer having a bondable surface, and mating the bondable surface of the semiconductor wafer with a die attach adhesive film sheet via its die attach adhesive layer.

15. The method according to claim 14, further comprising: include: D1. Dicing the semiconductor wafer with the die attach adhesive film mated to the surface of the semiconductor wafer to produce semiconductor elements with a die attach adhesive film of a predetermined size that can be used for further bonding.

16. The method according to claim 15, further comprising: include: E1. The semiconductor element having the die attach adhesive layer exposed for bonding is bonded to a carrier substrate through the die attach adhesive layer to form a semiconductor package or semiconductor assembly.

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