Resin composition for die attach films that exhibits excellent performance for large die applications

Abstract

Embodiments of the present disclosure relate to compositions for forming films and the use of such films in large die applications. In certain embodiments, the present disclosure relates to compositions comprising two or more resins, optionally one or more inorganic fillers, and one or more core-shell additives, along with a curing agent package, films produced from the compositions of the present disclosure, and cured films obtained after curing of the compositions of the present disclosure. In certain embodiments, the cured films obtained after curing of the compositions of the present disclosure have specific physical properties and / or combinations of physical properties.

Description

[Technical Field]

[0001] Embodiments of the present disclosure relate to compositions for forming films and the use of such films in large die applications. In certain embodiments, the present disclosure relates to compositions comprising two or more resins, optionally one or more inorganic fillers, one or more core-shell additives, and a curing agent package, films produced from the compositions of the present disclosure, and cured films obtained after curing of the compositions of the present disclosure. In certain embodiments, the cured films obtained after curing of the compositions of the present disclosure have specific physical properties and / or combinations of physical properties. [Background technology]

[0002] Looking toward the next generation of high-performance packages, the materials industry faces the need to improve the high-temperature properties of film materials (such as die attach film materials). Achieving this goal could provide benefits such as greater thermal stability and, consequently, greater reliability in applications across the automotive, computing, networking, and communications industries. Features that may be associated with improved high-temperature properties of film materials include a relatively high Tg (glass transition temperature) and a relatively high modulus of elasticity at relatively high temperatures, such as 200°C.

[0003] For reference, Figure 1 shows an example of the application of die attach film to adhere a silicon die to a metal lead frame surface. In Figure 1, 1 is molding compound, 2 is wire bond, 3 is silicon die, 4 is die attach film adhesive, 5 is copper lead frame, and 6 is substrate.

[0004] Currently, commercially available die attach films are primarily used in electronic package assemblies using bismaleimide triazine ("BT") laminate substrates for memory stacked die applications. Many of these die attach films are based on epoxy or epoxy / acrylate chemistry and typically do not have strong adhesion to metal substrates.

[0005] Therefore, it is desirable to improve the performance of die attach films on metal substrates and / or in large die applications. Summary of the Invention [Means for solving the problem]

[0006] In view of at least the matters discussed above, there is interest in compositions comprising two or more resins, optionally one or more inorganic fillers, and one or more core-shell additives together with a curing agent package, films made from the compositions, and cured films obtained after curing of the compositions.

[0007] Accordingly, provided herein are compositions particularly suited for die attach film applications, such as non-conductive die attach film applications, that have advantageous properties suitable for use in the automotive industry with high reliability requirements, such as high adhesion to multiple metal lead frame surfaces, including copper, silver, and PPF (NiPdAu plated copper lead frame, with Au on the outermost surface, Ni on the innermost surface, and a Pd layer sandwiched between them).

[0008] Die attach films made from these compositions exhibit low stress, which translates into low warpage, which is especially advantageous for large die applications.

[0009] In some embodiments, aspects of the present disclosure include: (a) two or more resins selected from the group consisting of: (i) at least one maleimide-containing resin, nadimide-containing resin, or itaconimide-containing resin, and (ii) an epoxy resin; (b) core-shell particles comprising a polymeric material having elastomeric or rubbery properties surrounded by a shell comprising a non-elastomeric polymeric material; (c) optionally, an inorganic filler; (d) a hardener package containing:

[0010] [ka]

[0011] wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms.

[0012] [ka]

[0013] wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms; and

[0014] [ka]

[0015] wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and R2 and R3 and R5 and R6 are each taken together, independently of one another, to form a ring of 3 to 7 atoms; (e) one or more additives selected from the group consisting of adhesion promoters and film formers; The present invention relates to a composition comprising:

[0016] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DSC has an onset temperature of 160 ° C to 180 ° C, DSC has a peak temperature of 180 ° C to 210 ° C, and The reaction heat exceeds 30 J / g.

[0017] In some embodiments, the composition is B-staged into a film, then laminated onto a 7 mm x 7 mm die and exposed to a temperature of about 175°C for about 1 hour, and exhibits at least the following physical properties: the die is measured to exhibit a warpage of less than about 100 μm.

[0018] In some embodiments, the composition is B-staged into a film and then laminated onto a metal lead frame or BT substrate over a 3 mm x 3 mm die and exposed to a temperature of about 175°C for about 4 hours, and exhibits at least the following physical properties: the film adheres to the metal lead frame and exhibits an adhesion force of at least 3 kgf per die.

[0019] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) storage modulus at 25°C is less than 2,500 MPa, and Glass transition temperature Tg exceeds 200°C.

[0020] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 100°C exceeds 50 MPa, and Glass transition temperature Tg exceeds 200°C.

[0021] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 150°C exceeds 20 MPa, and Glass transition temperature Tg exceeds 200°C.

[0022] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 200°C exceeds 10 MPa, and Glass transition temperature Tg exceeds 200°C.

[0023] In some embodiments, after application to a metal lead frame and curing at a temperature of 260°C, the composition exhibits a die shear strength of >9 kgf / die on a copper metal lead frame and >5 kgf / die on a silver metal lead frame.

[0024] In some embodiments, aspects of the present disclosure include:

[0025] [ka]

[0026] wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms.

[0027] [ka]

[0028] wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms; and

[0029] [ka]

[0030] wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and R2 and R3 and R5 and R6 are each taken together, independently of one another, to form a ring of 3 to 7 atoms. The present invention relates to a hardener package comprising: [Brief explanation of the drawings]

[0031] [Figure 1] Figure 1 shows a typical example of the application of a die attach film to adhere a silicon die to a metal lead frame surface. [Figure 2] FIG. 2 shows a schematic diagram of how the die attach film can be used in applications. [Figure 3] FIG. 3 shows DMA (Dynamic Mechanical Analysis) data for an exemplary composition of the present disclosure (Inventive Sample 5 after 1 hr post-cure at 175° C.) in terms of storage modulus (measured in MPa) versus temperature increase (measured in ° C.), loss modulus (measured in MPa) versus temperature increase (measured in ° C.), and tan δ (measured in ° C.) versus temperature increase (measured in ° C.). [Figure 4] FIG. 4 shows DSC (differential scanning calorimetry) data for an exemplary composition of the present disclosure (Inventive Sample 5) in terms of heat flow (measured in W / g) versus temperature rise (measured in ° C.). [Figure 5] FIG. 5 shows melt viscosity data for an exemplary composition of the present disclosure (Inventive Sample 5). DETAILED DESCRIPTION OF THE INVENTION

[0032] The compositions and methods of the present disclosure may be more readily understood by reference to the following detailed description in connection with the accompanying drawings, which form a part of this disclosure.

[0033] According to the present disclosure, in some embodiments, as described above: (a) two or more resins selected from the group consisting of: (i) at least one maleimide-containing resin, nadimide-containing resin, or itaconimide-containing resin, and (ii) an epoxy resin; (b) core-shell particles comprising a polymeric material having elastomeric or rubbery properties surrounded by a shell comprising a non-elastomeric polymeric material; (c) optionally, an inorganic filler; (d) a hardener package containing:

[0034] [ka]

[0035] (wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms.)

[0036] [ka]

[0037] wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms; and

[0038] [ka]

[0039] wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and R2 and R3 and R5 and R6 are each taken together, independently of one another, to form a ring of 3 to 7 atoms; (e) one or more additives selected from the group consisting of adhesion promoters and film formers.

[0040] In some embodiments, with reference to resin component (a)(i), the maleimide-containing resin, nadimide-containing resin, or itaconimide-containing resin may be represented by the following, respectively:

[0041] [ka]

[0042] (wherein: m is 1 to 15, p is 0 to 15, each R2 is independently selected from hydrogen or C1-6 alkyl, and J is a monovalent or polyvalent group containing organic and / or organosiloxane groups.)

[0043] In some embodiments, J is a monovalent or polyvalent group selected from: - hydrocarbyl or substituted hydrocarbyl species typically having in the range of from about 6 to about 500 carbon atoms, where the hydrocarbyl species is selected from alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, aryl, alkylaryl, arylalkyl, arylalkenyl, alkenylaryl, arylalkynyl, or alkynylaryl, although X can be aryl only if X comprises a combination of two or more different species; - a hydrocarbylene or substituted hydrocarbylene species typically having in the range of from about 6 to about 500 carbon atoms, where the hydrocarbylene species is selected from alkylene, alkenylene, alkynylene, cycloalkylene, cycloalkenylene, arylene, alkylarylene, arylalkylene, arylalkenylene, alkenylarylene, arylalkynylene, or alkynylarylene. - substituted or unsubstituted C6-C10 aryl; - heterocyclic or substituted heterocyclic species typically having in the range of about 6 to about 500 carbon atoms; - polysiloxane; - polysiloxane-polyurethane block copolymer; or - One or more of the above and a 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- in combination with a linker selected from 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-; where each R is independently hydrogen, alkyl, or substituted alkyl.

[0044] In some embodiments, J is selected from the group consisting of substituted or unsubstituted C aryl, oxyalkyl, thioalkyl, aminoalkyl, carboxylalkyl, oxyalkenyl, thioalkenyl, aminoalkenyl, carboxyalkenyl, oxyalkynyl, thioalkynyl, aminoalkynyl, carboxyalkynyl, oxycycloalkyl, thiocycloalkyl, aminocycloalkyl, carboxycycloalkyl, oxycycloalkenyl, thiocycloalkenyl, aminocycloalkenyl, carboxycycloalkenyl, 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, carboxy Arylalkenyl, oxyalkenylaryl, thioalkenylaryl, aminoalkenylaryl, carboxyalkenylaryl, oxyarylalkynyl, thioarylalkynyl, aminoarylalkynyl, carboxyarylalkynyl, oxyalkynylaryl, thioalkynylaryl, aminoalkynylaryl or carboxyalkynylaryl, oxyalkylene, thioalkylene, aminoalkylene, carboxyalkylene, oxyalkenylene, thioalkenylene, aminoalkenylene, carboxyalkenylene alkynylene, oxyalkynylene, thioalkynylene, aminoalkynylene, carboxyalkynylene, oxycycloalkylene, thiocycloalkylene, aminocycloalkylene, carboxycycloalkylene, oxycycloalkenylene, thiocycloalkenylene, aminocycloalkenylene, carboxycycloalkenylene, oxyarylene, thioarylene, aminoarylene, carboxyarylene, oxyalkylarylene, thioalkylarylene, aminoalkylarylene, carboxyalkylarylene, oxyarylalkylene,thioarylalkylene, aminoarylalkylene, carboxyarylalkylene, oxyarylalkenylene, thioarylalkenylene, aminoarylalkenylene, carboxyarylalkenylene, oxyalkenylarylene, thioalkenylarylene, aminoalkenylarylene, carboxyalkenylarylene, oxyarylalkynylene, thioarylalkynylene, aminoarylalkynylene, carboxyarylalkynylene, oxyalkynylarylene, thioalkynylarylene, aminoalkynylarylene, carboxyalkynylarylene, heteroarylene, oxyheteroarylene, thioheteroarylene, aminoheteroarylene, carboxyheteroarylene, heteroatom-containing divalent or polyvalent cyclic group, oxyheteroatom-containing divalent or polyvalent cyclic group, thioheteroatom-containing divalent or polyvalent cyclic group, aminoheteroatom-containing divalent or polyvalent cyclic group, or carboxyheteroatom-containing divalent or polyvalent cyclic group.

[0045] In some embodiments, the maleimide-containing resin is represented by the following:

[0046] [ka]

[0047] wherein each R is independently selected from the group consisting of H and substituted or unsubstituted alkyl; each m is selected from the group consisting of 0, 1, 2, 3, and 4; n is 0, 1, 2, 3, 4, and 5.

[0048] In some embodiments, the composition comprises a compound represented by the formula:

[0049] [ka]

[0050] This compound is abbreviated as BMI-5100 (chemical name: 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, Daiwa Kasei, Japan), and has an average molecular weight of approximately 300 as determined by gel permeation chromatography (GPC).

[0051] In some embodiments, the maleimide-containing resin is represented by the following:

[0052] [ka]

[0053] wherein n is 0, 1, 2, 3, 4, or 5.

[0054] In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of 180 to 400. A maleimide equivalent weight is the gram weight of a resin containing one equivalent of maleimide functional groups. In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of 220. In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of 300. In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of about 400. In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of about 390 to about 400. In some embodiments, the maleimide-containing resin is a BMI resin having a maleimide equivalent weight of 390 to 400.

[0055] In some embodiments, the maleimide-containing resin is included in an amount ranging from about 1% to about 20% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 1% to about 15% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 3% to about 15% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 1% to about 5% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 5% to about 20% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 5% to about 15% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 10% to about 20% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 10% to about 15% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 12% to about 17% by weight. In some embodiments, the maleimide-containing resin is included in an amount ranging from about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, or about 20 wt%.

[0056] In some embodiments, the itaconimide-containing resin is represented by the following:

[0057] [ka]

[0058] wherein Ar is a substituted or unsubstituted aryl group.

[0059] In some embodiments, the itaconimide-containing resin is:

[0060] [ka]

[0061] In some embodiments, the nadimide is represented by the following:

[0062] [ka]

[0063] During the ceremony, Ar is substituted or unsubstituted aryl; R is selected from the group consisting of H, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, and substituted or unsubstituted heteroaryl.

[0064] In some embodiments, desirably, the maleimide-, nadimide-, or itaconimide-containing resin (a)(i) is selected from the group consisting of:

[0065] [ka]

[0066] In the formula, n is 0 to 2.

[0067] [ka]

[0068] In the formula, R is alkyl having 1 to 4 carbon atoms, phenyl, or alkylphenyl having 7 to 11 carbon atoms, and n is 1 to 12.

[0069] [ka]

[0070] In the formula, R is alkyl having 1 to 4 carbon atoms or phenyl, x is diarylalkylene, and n is 1 to 2.

[0071] As mentioned above, the compositions of the present disclosure include, among other components, an epoxy resin. A wide variety of epoxy resins are contemplated for use in the present invention, such as liquid epoxy resins based on bisphenol A, solid epoxy resins based on bisphenol A, liquid epoxy resins based on bisphenol F (e.g., Epiclon EXA-835LV), multifunctional epoxy resins based on phenol novolac resins, dicyclopentadiene-type epoxy resins (e.g., Epiclon HP-7200L), naphthalene-type epoxy resins, and the like, as well as mixtures of two or more thereof.

[0072] Examples of epoxy resins contemplated for use in the present invention include diepoxides of cycloaliphatic alcohols, hydrogenated bisphenol A (commercially available as Epalloi 5000), difunctional cycloaliphatic glycidyl ester of hexahydrophthalic anhydride (commercially available as Epalloi 5200), Epiclon EXA-835LV, Epiclon HP-7200L, and the like, and mixtures of two or more thereof.

[0073] In certain embodiments, the epoxy resin may include a combination of two or more different bisphenol-based epoxies. These bisphenol-based epoxies may be selected from bisphenol A, bisphenol F, or bisphenol S epoxies, or combinations thereof. Additionally, two or more different bisphenol epoxies within the same resin type (such as A, F, or S) may be used.

[0074] Commercially available examples of bisphenol epoxies contemplated for use in the present invention include bisphenol F type epoxies (such as RE-404-S manufactured by Nippon Kayaku Co., Ltd., Epiclon 830 (RE1801), 830S (RE1815), 830A (RE1826) and 830W manufactured by Dainippon Ink and Chemicals Co., Ltd., and RSL1738 and YL-983U manufactured by Resolution Co., Ltd.) and bisphenol A type epoxies (such as YL-979 and 980 manufactured by Resolution Co., Ltd.).

[0075] The above bisphenol epoxies, commercially available from Dai Nippon Printing, are advertised as liquid, undiluted epichlorohydrin-bisphenol F epoxies with much lower viscosities than conventional bisphenol A-based epoxies and similar physical properties to liquid bisphenol A epoxies. While the bisphenol F epoxies have lower viscosities than the bisphenol A epoxies, all other properties are the same between the two epoxies, resulting in lower viscosity and therefore more fluid underfill sealant materials. The EEWs of these four bisphenol F epoxies range from 165 to 180. Their viscosities at 25°C range from 3,000 to 4,500 cps (except for RE1801, which has an upper viscosity limit of 4,000 cps). The hydrolyzable chloride content is reported as 200 ppm for RE1815 and 830W, and 100 ppm for RE1826.

[0076] The bisphenol epoxies mentioned above, available commercially from Resolution, are advertised as low-chloride liquid epoxies. Bisphenol A epoxies have EEW (g / eq) of 180-195 and viscosities of 100-250 cps at 25°C. Total chloride content is reported to be 500-700 ppm for YL-979 and 100-300 ppm for YL-980. Bisphenol F epoxies have EEW (g / eq) of 165-180 and viscosities of 30-60 at 25°C. Total chloride content is reported to be 500-700 ppm for RSL-1738 and 150-350 ppm for YL-983U.

[0077] In addition to bisphenol epoxies, other epoxy compounds are contemplated for use as the epoxy resin (a)(ii) in the compositions of the present disclosure. For example, cycloaliphatic epoxies such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexyl carbonate can be used. Mono-, di-, or multi-functional reactive diluents may also be used to adjust the viscosity and / or lower the Tg of the resulting resin material. Exemplary reactive diluents include butyl glycidyl ether, cresyl glycidyl ether, polyethylene glycol glycidyl ether, polypropylene glycol glycidyl ether, and the like.

[0078] Other epoxies suitable for use in the present invention 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, amino alcohols, 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 Chiba Specialty Chemicals, and PGA-X and PGA-C from Sherwin-Williams.

[0079] Suitable monofunctional epoxy co-reactant diluents for optional use herein also include those having a viscosity lower than that of the epoxy component, typically less than about 250 cps. The monofunctional epoxy co-reactant diluent may have an epoxy group with an alkyl group 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 esters, C 6-28 Examples thereof include alkylphenol glycidyl ether.

[0080] In some embodiments, the epoxy resin is novolac epoxy EEW200, novolac epoxy EEW300, or novolac epoxy EEW140.

[0081] In some embodiments, the epoxy resin is a compound represented by the following formula:

[0082] [ka]

[0083] In the formula, n is 0, 1, 2, 3, 4, or 5, and m is 0, 1, 2, 3, 4, or 5.

[0084] In some embodiments, the epoxy resin is included in an amount ranging from about 1% to about 30% by weight. In some embodiments, the epoxy resin is included in an amount ranging from 1% to about 25% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 1% to about 20% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 1% to about 15% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 3% to about 15% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 1% to about 5% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 5% to about 20% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 5% to about 15% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 10% to about 20% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 15% to about 30% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 15% to about 25% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 10% to about 15% by weight. In some embodiments, the epoxy resin is included in an amount ranging from about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about 26%, about 27%, about 28%, about 29%, or about 30% by weight.

[0085] Desirably, resin (a) is present in a weight ratio of (a)(i):(a)(ii) of from about 0.3:1 to about 6:1.

[0086] The compositions of the present disclosure include, among other components, core-shell rubber, as described above. Rubber particles having a core-shell structure are an additional component of the compositions of the present invention. Such particles generally have a core made of a polymeric material with elastomeric or rubbery properties (i.e., a glass transition temperature below about 0°C, e.g., below about -30°C) and a shell made of a non-elastomeric polymeric material (i.e., a thermoplastic or thermoset / crosslinked polymer with a glass transition temperature above ambient temperature, e.g., above about 50°C).

[0087] For example, the core may be composed of a diene homopolymer or copolymer (e.g., a homopolymer of butadiene or isoprene, or a copolymer of butadiene or isoprene with one or more ethylenically unsaturated monomers such as vinyl aromatic monomers, (meth)acrylonitrile, (meth)acrylates), and the shell may be composed of a polymer or copolymer of one or more monomers having a moderately high glass transition temperature, such as (meth)acrylates (e.g., methyl methacrylate), vinyl aromatic monomers (e.g., styrene), vinyl cyanides (e.g., acrylonitrile), unsaturated acids and anhydrides (e.g., acrylic acid), (meth)acrylamides, etc. Other rubbery polymers, including polybutyl acrylate or polysiloxane elastomers (e.g., polydimethylsiloxane, especially crosslinked polydimethylsiloxane), may also be suitably used for the core. The rubber particles may be composed of two or more layers (e.g., a central core made of one rubbery material may be surrounded by a second core made of a different rubbery material, or the rubbery core may be surrounded by two shells with different compositions, or the rubber particles may have a soft-core-hard-shell-soft-hard-shell structure). In one embodiment of the present invention, the rubber particles used are composed of a core and at least two concentric shells with different chemical compositions and / or properties. Either the core or the shell, or both the core and the shell, may be crosslinked (e.g., ionic or covalent). The shell may be grafted to the core. The polymer constituting the shell may have one or more different types of functional groups (e.g., epoxy groups) that can interact with other components of the composition of the present invention.

[0088] Typically, the core comprises 50 to 95% by weight of the rubber particle, and the shell comprises 5 to 50% by weight of the rubber particle.

[0089] The core-shell rubber particles are nanoscale in size, i.e. the average diameter of the rubber particles is less than 500 nm, for example less than 200 nm, preferably in the range of 25 to 100 nm.

[0090] Methods for making rubber particles having a core-shell structure are well known in the art and are described, for example, in U.S. Patent Nos. 4,419,496, 4,778,851, 5,981,659, 6,111,015, 6,147,142 and 6,180,693.

[0091] Rubber particles having a core-shell structure may be prepared as a masterbatch in which the rubber particles are dispersed in one or more epoxy resins, such as diglycidyl ether of bisphenol A. For example, the rubber particles are typically prepared as an aqueous dispersion or emulsion. Such a dispersion or emulsion is mixed with the desired epoxy resin or mixture of epoxy resins, and water and other volatile materials are removed by distillation or the like. One method for preparing such a masterbatch is described in further detail in International Patent Publication No. WO 2004 / 108825. For example, an aqueous latex of rubber particles may be contacted with an organic medium that is partially soluble in water, and then contacted with another organic medium that is less partially soluble in water than the first organic medium to separate the water and provide a dispersion of rubber particles in the second organic medium. This dispersion may then be mixed with the desired epoxy resin and the volatile materials removed by distillation or the like to provide the masterbatch.

[0092] Particularly suitable dispersions of rubber particles having a core-shell structure in an epoxy resin matrix are available from Kaneka Corporation, such as Kaneka MX-120 (a masterbatch of 25 wt. % nano-sized core-shell rubber in a diglycidyl ether of bisphenol A matrix) and Kaneka MX-156.

[0093] For example, the core may be formed primarily from a feedstock of polybutadiene, polyacrylate, polybutadiene / acrylonitrile blends, polyols and / or polysiloxanes, or other monomers that provide a low glass transition temperature.

[0094] The outer shell may be formed primarily from polymethyl methacrylate, polystyrene, or polyvinyl chloride, or other monomeric materials that provide a higher glass transition temperature.

[0095] The core-shell rubber thus produced may be dispersed in an epoxy matrix or a phenolic matrix. Examples of epoxy matrices include diglycidyl ethers of bisphenol A, F, or S, or biphenol, novolac epoxies, epoxidized nitrogen-based amines, and cycloaliphatic epoxies. Examples of phenolic resins include phenoxy resins based on bisphenol A.

[0096] The core-shell rubber may be dispersed in the epoxy or phenolic matrix in the range of 5 to 50% by weight, preferably 15 to 25% by weight.

[0097] In this high core-shell rubber content range, an increase in the viscosity of the dispersion may be observed in a relatively short period of time, and flocculation, sedimentation, and gelation of the dispersion may also be observed.

[0098] In the compounds of the present invention, the use of these core-shell rubbers results in reinforcement upon cure of the compound, regardless of the temperature used to cure the compound. That is, due to the inherent two-phase separation of the compound with the core-shell rubber (as opposed to, for example, a liquid rubber that is miscible or partially miscible in the compound and may solidify at a temperature different from that used to cure the compound), the two-phase separation within the compound is observed to be nearly uniform in nature, thereby minimizing disruption of the matrix properties.

[0099] Many of the core-shell rubbers commercially available from Kaneka are believed to have cores made from (meth)acrylate-butadiene-styrene copolymers, with the butadiene being the primary component of the phase-separated particles dispersed in the epoxy resin. Other commercially available masterbatches of core-shell rubber particles dispersed in epoxy resin include Geniopal M23A (a dispersion of 30 wt. % core-shell particles in an aromatic epoxy resin based on bisphenol A diglycidyl ether; the core-shell particles have an average diameter of approximately 100 nm and contain a crosslinked silicone elastomer core grafted with an epoxy-functional acrylate copolymer, with the silicone elastomer core accounting for approximately 65 wt. %), available from Wacker Chemie, Germany.

[0100] Core-shell rubbers are included, which include a polymer core and at least two polymer layers surrounding the core, each layer having a different polymer composition than the other layers, and at least one polymer layer includes a polymer that is a gradient polymer, the gradient polymer being a copolymer of at least two different monomers (A) and (B) having a gradient of repeat units arranged from predominantly monomer (A) to predominantly monomer (B) along the copolymer, and when mixed, the peroxide catalyst initiates cure of the free radical curable component and the transition metal initiates cure of the cyanoacrylate component.

[0101] The core-shell rubber comprises particles having a particle size of 170 to 350 nm and a pH of 6 to 7.5, and comprises one polymer rubber core comprising at least partially crosslinked isoprene or butadiene and optionally styrene, and at least two polymer layers, at least one of which is an outermost thermoplastic shell layer having a Tg greater than 25°C, each layer having a different polymer composition.

[0102] The core-shell rubber must include a polymeric rubber core surrounded by a polymeric layer, the polymeric core layer having a glass transition temperature below 0°C and a different polymer composition from the polymeric rubber core, and the polymeric core layer is a gradient zone. Desirably, the core-shell rubber must include at least one polymeric core layer and at least two polymeric shell layers, the polymeric core layer having a different composition from the polymeric shell layers, each shell layer having a different polymer composition from the other shell layers, and at least one polymeric shell layer being a gradient zone.

[0103] The core-shell rubber should comprise a polymeric rubber core having a glass transition temperature below 0°C, e.g., below about -10°C, desirably below about -20°C, advantageously below about -25°C, and most advantageously below about -40°C, e.g., from about -80°C to about -40°C.

[0104] The core-shell rubber should include a polymeric rubber core constructed from one or more isoprene or butadiene homopolymers, isoprene-butadiene copolymers, copolymers of isoprene with up to 98% by weight of vinyl monomers, and copolymers of butadiene with up to 98% by weight of vinyl monomers. The vinyl monomers may be styrene, alkylstyrene, acrylonitrile, alkyl (meth)acrylates, or butadiene or isoprene. Desirably, the core should be constructed from one of polybutadiene, copolymers of butadiene and styrene, or terpolymers of methyl methacrylate, butadiene, and styrene.

[0105] In some embodiments, the core may be covered by a core layer, which means that the polymer composition of the core layer has a glass transition temperature (Tg) below 0° C., for example below about −10° C., desirably below about −20° C., and advantageously below about −25° C. Desirably, the core layer is a gradient polymer.

[0106] The core-shell rubber should have one or more shells, preferably two shells, with at least the outer shell in contact with the thermoplastic matrix having a Tg greater than about 25°C, for example greater than about 50°C.

[0107] The shell of the core-shell rubber may be constructed from one or more of a styrene homopolymer, an alkylstyrene homopolymer, or a methyl methacrylate homopolymer, or a comonomer comprising at least 70% by weight of one of the above monomers, and at least one comonomer selected from other of the above monomers, another alkyl (meth)acrylate, vinyl acetate, and acrylonitrile. The shell may be functionalized, for example, with anhydrides of unsaturated carboxylic acids, unsaturated carboxylic acids, and unsaturated epoxides, such as maleic anhydride, (meth)acrylic acid glycidyl methacrylate, hydroxyethyl methacrylate, and alkyl (meth)acrylamide.

[0108] Gradient copolymers are produced by placing them between two layers, creating a gradient zone where one side is richer in the monomer / polymer from the adjacent layer and the other side is richer in a different monomer / polymer forming the next layer. Gradient zones between the core and shell, or between two polymer shells, can be produced, for example, by using monomers with different copolymerization parameters or by running the reaction in a semi-continuous mode under starvation-feed conditions where the rate of monomer addition is slower than the reaction rate. However, gradient polymers never become the outermost layer of a core-shell particle.

[0109] The monomers used to form the gradient polymer are selected from the monomers listed for the core and each shell based on the function of the adjacent layer.

[0110] The Young's modulus of the polymer rubber core is always lower than that of the other polymer layers, and the Young's modulus of the layer containing the gradient polymer is always lower than that of the outermost layer.

[0111] The core-shell rubber should be in the form of microparticles having a rubber core and at least one thermoplastic shell, the particle size of which is generally less than 1 μm, advantageously between 50 nm and 500 nm, preferably between 100 nm and 400 nm, most preferably between 150 nm and 350 nm, advantageously between 170 nm and 350 nm.

[0112] Core-shell rubbers may be produced by emulsion polymerization. For example, a suitable method is a two-stage polymerization technique in which the core and shell are produced in two successive emulsion polymerization stages. If an additional shell is present, another emulsion polymerization stage follows. Graft copolymers are obtained by graft polymerizing a monomer or mixture of monomers containing at least an aromatic vinyl, alkyl methacrylate, or alkyl acrylate in the presence of a latex containing a butadiene-based rubber polymer. Commercially available examples of such core-shell rubbers are available from Arkema, Inc., Cary, North Carolina, under the registered trademark Clearstrength. For example, Arkema describes Clearstrength XT100 as a methyl methacrylate-butadiene-styrene core-shell toughener that is compatible with a variety of monomers, easily disperses in most liquid resin systems, and provides toughening over a wide range of operating temperatures while having limited impact on viscosity.

[0113] Typically, the core comprises from about 50 to about 95% by weight of the rubber particle, and the shell comprises from about 5 to about 50% by weight of the rubber particle.

[0114] Preferably, the rubber particles are relatively small. For example, the average particle size may be about 0.03 to about 2 microns, or about 0.05 to about 1 micron. The average diameter of the rubber particles may be less than about 500 nm, for example, less than about 200 nm. For example, the average diameter of the core-shell rubber particles may be in the range of about 25 to about 200 nm.

[0115] Core-shell rubbers are typically offered for commercial sale and typically provide a substantially uniform dispersion, so these core-shell rubbers often toughen compositions in a predictable manner (in terms of temperature neutrality with respect to cure).

[0116] The rubber particles may be used in a dry state or dispersed in a matrix, as described above.

[0117] Combinations of different rubber particles may be advantageously used in the present invention, which may differ, for example, in particle size, the glass transition temperature of each material, whether and to what extent the materials are functionalized, and whether and how they are surface treated.

[0118] The core-shell rubber should be present in an amount ranging from about 1 to about 50 weight percent, for example from about 5 to about 30 weight percent, and desirably from about 10 to about 20 weight percent, based on the total weight of the composition.

[0119] The core-shell particles (b) should desirably be present in a weight ratio with the resin (a) of from about 0.15:1 to about 0.95:1 (b):(a).

[0120] The compositions of the present invention may also include inorganic fillers such as silica.

[0121] For example, if an inorganic filler is present, it may be silica in the form of fumed silica, fused silica, or surface-activated silica, all of which are nanoscale. The silica nanoparticles can be pre-dispersed in the epoxy resin and may be selected from those commercially available under the registered trademark Nanopox, such as Nanopox XP0314, XP0516, and XP0525, from Hanse Chemie GmbH, Germany. These Nanopox brand products are silica nanoparticles dispersed in epoxy resin at levels up to about 50% by weight. These Nanopox brand products are believed to have particle sizes ranging from about 5 nm to about 80 nm. Nanopox XP0314 is reported by the manufacturer to contain 40% by weight of silica particles with a particle size of less than 50 nm in a cycloaliphatic epoxy resin.

[0122] In some embodiments, the inorganic filler is a non-conductive filler such as silica, as described above. In some embodiments, the filler is silica, calcium silicate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, aluminum oxide (AlO 3 ), zinc oxide (ZnO), magnesium oxide (MgO), aluminum nitride (AlN), boron nitride (BN), carbon nanotubes, diamond, clay, aluminosilicates, etc., and mixtures of two or more thereof.

[0123] In some embodiments, the inorganic filler is an inorganic non-conductive filler comprising particles with a maximum particle size of 5 μm or less, for example, in some embodiments, the filler has a particle size of about 0.1 μm to about 5 μm, or 0.1 μm to 5 μm.

[0124] In some embodiments, inorganic fillers are included in an amount greater than 0 wt %, such as in the range of about 10 wt % to about 70 wt %, for example up to about 40 wt %, desirably up to about 25 wt %.

[0125] The inorganic filler (c) should desirably be present in a weight ratio with the resin (a) of from about 0.15:1 to about 0.90:1 (c):(a).

[0126] The inorganic filler (c) should desirably be present in a weight ratio with the core-shell particles (b) of from about 0.95:1 to about 5:1 (c):(b).

[0127] The composition also includes a curing agent package. Desirably, the curing agent package comprises:

[0128] [ka]

[0129] (wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms.)

[0130] [ka]

[0131] (wherein R1, R2, R3, and R4 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms); and

[0132] [ka]

[0133] wherein R1, R2, R3, R4, R5, and R6 are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and R2 and R3 and R5 and R6 are each taken together, independently of one another, to form a ring of 3 to 7 atoms. It encompasses a combination of:

[0134] Desirably, the curing agent package (d) includes an aromatic urea, 4,4-diaminodiphenyl sulfone, and dicyandiamide.

[0135] [ka]

[0136] The hardener package should be used in an amount of about 7.0% to about 10% by weight in the composition.

[0137] The ratio of the three components of the curative package may be from about 35 parts:100 parts:10 parts to about 40 parts:135 parts:15 parts.

[0138] The hardener package (d) may be present in a weight ratio with the resin (a) of (d):(a) from about 0.2:1 to about 0.35:1.

[0139] In some embodiments, after the composition forms a film, the film has particular characteristics and / or properties that make it suitable for use in thermocompression bonding processes. For example, in some embodiments, after the composition is B-staged into a film, it exhibits at least the following physical properties: DSC has an onset temperature of 160 ° C to 180 ° C, DSC has a peak temperature of 180 ° C to 210 ° C, and The reaction heat exceeds 30 J / g.

[0140] In some embodiments, the composition is B-staged into a film, then laminated onto a 7 mm x 7 mm die and exposed to a temperature of about 175°C for about 1 hour, and exhibits the following physical properties: the die is measured to exhibit a warpage of less than about 100 μm.

[0141] In some embodiments, the composition is B-staged into a film, which is then laminated onto a metal lead frame or BT substrate and exposed to a temperature of about 175°C for about 4 hours, and exhibits at least the following physical properties: the film adheres to the metal lead frame and exhibits an adhesion force of at least 3 kgf per die.

[0142] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows a storage modulus of <2,500 MPa at 25°C, and Glass transition temperature Tg exceeds 200°C.

[0143] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 100°C is <50 MPa, and Glass transition temperature Tg exceeds 200°C.

[0144] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 150°C is <20 MPa, and Glass transition temperature Tg exceeds 200°C.

[0145] In some embodiments, the composition, after being B-staged into a film, exhibits at least the following physical properties: DMA (Dynamic Mechanical Analysis) shows a storage modulus of <10 MPa at 200°C, and Glass transition temperature Tg exceeds 200°C.

[0146] In some embodiments, after application to a metal lead frame and curing at a temperature of 260°C, the composition exhibits a die shear strength of >9 kgf / die on a copper metal lead frame and >5 kgf / die on a silver metal lead frame.

[0147] In some embodiments, after the composition forms a cured film, the cured film has a Tg of >100°C, >125°C, >150°C, >160°C, >165°C, >170°C, >175°C, >180°C, >185°C, >190°C, >200°C, >210°C, >220°C, >230°C, >240°C, >250°C, >260°C, >270°C, >280°C, >290°C, or >300°C, respectively, as measured by dynamic mechanical analysis (DMA). In some embodiments, after the composition forms a cured film, the cured film has a Tg of 100°C to 110°C, 110°C to 120°C, 120°C to 130°C, 130°C to 140°C, 140°C to 150°C, 150°C to 160°C, 160°C to 170°C, 170°C to 180°C, 180°C to 190°C, 190°C to 200°C, 200°C to 210°C, 210°C to 220°C, 220°C to 230°C, 230°C to 240°C, 240°C to 250°C, 250°C to 260°C, 260°C to 270°C, 270°C to 280°C, 280°C to 290°C, or 290°C to 300°C, each measured by DMA.

[0148] In some embodiments, after the composition forms a cured film, the cured B-stage film has a storage modulus at 25°C of <2,500 MPa, <2,000 MPa, <1,500 MPa, <1000 MPa, <500 MPa, <250 MPa, or <200 MPa.

[0149] In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus at 25° C. of <2,500 MPa, <2,000 MPa to <1,500 MPa, <1,500 MPa to <1,000 MPa, <1,000 MPa to <500 MPa, <500 MPa to <250 MPa, or <250 MPa to <200 MPa. In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus at 25° C. of <2,500 MPa to <200 MPa.

[0150] In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus of >50 MPa, >100 MPa, >200 MPa, >300 MPa, >400 MPa, >500 MPa, >600 MPa, >700 MPa, >800 MPa, >900 MPa, or >1,000 MPa at 100° C. In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus of 50 MPa to 200 MPa, 200 MPa to 300 MPa, 300 MPa to 400 MPa, 400 MPa to 500 MPa, 500 MPa to 600 MPa, 600 MPa to 700 MPa, 700 MPa to 800 MPa, 800 MPa to 900 MPa, or 900 MPa to 1,000 MPa at 100° C.

[0151] In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus at 150° C. of >20 MPa, >100 MPa, >110 MPa, >120 MPa, >130 MPa, >140 MPa, >150 MPa, >160 MPa, >170 MPa, >180 MPa, >190 MPa, or >200 MPa. In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus at 100° C. of 20 MPa to 100 MPa, 100 MPa to 120 MPa, 120 MPa to 130 MPa, 130 MPa to 140 MPa, 140 MPa to 150 MPa, 150 MPa to 160 MPa, 160 MPa to 170 MPa, 170 MPa to 180 MPa, 180 MPa to 190 MPa, or 190 MPa to 200 MPa.

[0152] In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus of >10 MPa, >45 MPa, >50 MPa, >55 MPa, or >60 MPa, >65 MPa, >70 MPa, >75 MPa, >80 MPa, >85 MPa, >90 MPa, >95 MPa, or >100 MPa at 200° C. In some embodiments, after the composition forms a cured film, the cured B-staged film has a storage modulus of 10 MPa to 50 MPa, 50 MPa to 55 MPa, 55 MPa to 60 MPa, 60 MPa to 65 MPa, 65 MPa to 70 MPa, 70 MPa to 75 MPa, 75 MPa to 80 MPa, 80 MPa to 85 MPa, 85 MPa to 90 MPa, 90 MPa to 95 MPa, or 95 MPa to 100 MPa at 200° C.

[0153] In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 10 Pa·s to 2,000 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2. In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 20 Pa·s to 1,800 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2. In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 30 Pa·s to 1,500 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2. In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 50 Pa·s to 1,200 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2. In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 10 Pa·s to 2,000 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2. In some embodiments, after the composition forms a cured film, the B-staged film has a minimum film melt viscosity of 100 Pa·s to 1,000 Pa·s when measured using a DHR2 rheometer at a heating rate of 10°C / min in N2.

[0154] In some embodiments, after the composition forms a cured film, the B-staged film has a DSC onset temperature of 160°C to 170°C, 170°C to 180°C, as measured by differential scanning calorimetry ("DSC") in N2 at a heating rate of 10°C / min.

[0155] In some embodiments, after the composition forms a cured film, the B-staged film has a DSC onset temperature of about 160°C to about 170°C, about 170°C to about 180°C, about 180°C to about 190°C, about 190°C to about 200°C, or about 200°C to about 210°C, as measured by DSC in N2 at a heating rate of 10°C / min.

[0156] In some embodiments, the present disclosure refers to certain organic groups as being "substituted." The term "substituted" means that the organic group in question has one or more substituents, where a substituent is an atom or group of atoms that replaces a hydrogen atom on the organic group in question. When an organic group is substituted, the substituents can replace one or more hydrogen atoms, ranging from replacing exactly one hydrogen atom to replacing all hydrogen atoms on the organic group in question. When an organic group has multiple substituents, the substituents are independently selected and can be, but do not have to be, identical.

[0157] In some embodiments, the present disclosure refers to certain organic groups as being "unsubstituted." The term "unsubstituted" means that the organic group in question does not bear any substituents, as that term is defined above.

[0158] The compositions of the present invention may also include co-reactants, curing agents and / or catalysts, examples of which include Lewis acids such as phenols and their derivatives, strong acids such as alkylene acids, and cationic catalysts.

[0159] The compositions of the present invention also include adhesion promoters and film formers.

[0160] As used herein, the term "adhesion promoter" refers to a compound that enhances the adhesive properties of a formulation into which it is incorporated. Adhesion promoters can be organic or inorganic compounds and can include combinations thereof. Non-limiting examples of adhesion promoters include organozirconate compounds, organotitanate compounds, and silane coupling agents. In some embodiments, the adhesion promoter is Z6040 from Dow Corporation, Midland, Michigan.

[0161] In some embodiments, the adhesion promoter is included in an amount ranging from about 0.1% to about 5% by weight. In some embodiments, the adhesion promoter is included in an amount ranging from about 0.1% to about 1.0% by weight. In some embodiments, the adhesion promoter is included in an amount ranging from about 0.5% to about 1.0% by weight. In some embodiments, the adhesion promoter is included in an amount ranging from about 0.5% to about 1.5% by weight. In some embodiments, the adhesion promoter is included in an amount ranging from about 1% to about 2% by weight, from about 2% to about 3% by weight, from about 3% to about 4% by weight, or from about 4% to about 5% by weight.

[0162] The term "film former" as used herein refers to a compound that aids in the formation of a film, for example, by increasing the viscosity of the combined materials. Non-limiting examples of film formers include, but are not limited to, copolymer ethylene acrylic elastomers, natural or synthetic rubbers such as substituted polyethylene, resins such as polyvinyl butyral resins and chlorosulfonated polyethylene synthetic rubber (CSM), partially crosslinked butyl rubber compounds such as butyl rubber products commercially available from Royal Elastomers of New Jersey under the brand names KALAR, DPR, ISOLENE, and KALENE, and ethylene acrylic elastomer materials such as VAMAC available from DuPont. Additional non-limiting examples of film formers include, but are not limited to, acrylic polymers such as butyl acrylate-ethyl acrylate-acetonitrile copolymers and ethyl acrylate-acetonitrile copolymers (e.g., polymers containing glycidyl functional groups), commercially available examples of which include those from Nagase of Japan.

[0163] In some embodiments, the film-forming agent (or binder resin) is included in an amount ranging from about 1% to about 25% by weight. In some embodiments, the binder resin is included in an amount ranging from about 1% to about 20% by weight. In some embodiments, the binder resin is included in an amount ranging from about 10% to about 20% by weight. In some embodiments, the binder resin is included in an amount ranging from about 13% to about 18% by weight. In some embodiments, the binder resin is included in an amount ranging from about 14% to about 16% by weight. In some embodiments, the binder resin is included in an amount of about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 21%, about 22%, about 23%, about 24%, or about 25% by weight.

[0164] Aspects of the present disclosure also relate to methods of making B-staged and / or cured films.

[0165] In some embodiments, a method for producing a cured film comprises: (i) two or more resins selected from the group consisting of maleimide-containing resins, nadimide-containing resins, itaconimide-containing resins, and (ii) epoxy resins; core-shell particles; optionally an inorganic filler; a hardener package; providing a composition comprising: forming the composition into a film; and exposing the cast film to elevated temperatures to harden the film; Includes.

[0166] In some embodiments of the method of making a cured film, the two or more resins selected from the group consisting of maleimide-containing resins, nadimide-containing resins, itaconimide-containing resins, and epoxy resins are as disclosed elsewhere herein, and are optionally present in the amounts disclosed elsewhere herein.

[0167] In some embodiments of the method of making a cured film, the core-shell rubber is as disclosed elsewhere herein, and is optionally present in the amounts disclosed elsewhere herein.

[0168] In some embodiments of the method of making a cured film, the inorganic filler is as disclosed elsewhere herein, and is optionally present in the amounts disclosed elsewhere herein.

[0169] In some embodiments of the method of making a cured film, one or more additives selected from adhesion promoters and film formers are disclosed elsewhere herein, and are optionally present in the amounts disclosed elsewhere herein. [Example]

[0170] Example 1 Sample preparation A screening formulation to identify a curative package according to the present invention was prepared by combining the ingredients shown below in Table 1. As can be seen, the only variable in the ingredients is the catalyst.

[0171] [Table 1]

[0172] Catalyst 1 is 4,4-DDS (4,4-diaminodiphenyl sulfone); Catalyst 2 is a urea-type curing accelerator; and Catalyst 3 is DICY (dicyandiamide).

[0173] Preparation of varnish A silica filler slurry in an appropriate solvent was cavitated for dispersion. The required amount of organic components was weighed into a filler slurry container and mixed by hand for approximately 5 minutes. After that, sufficient solvent was added to achieve a solids content of 40-50% and a viscosity of 100-400 cps. Premixing continued for approximately 5-10 minutes in a high-speed mixer (approximately 1000-3000 rpm). The resulting varnish was filtered through a 10 μm filter to remove any oversized or coarse resin or filler particles.

[0174] Film preparation Film sheet samples were prepared by pouring the slurry onto a clean, prepared surface using a coating machine. The slurry was then heated in a retort oven to produce a stable coating film that adhered well to the substrate (release liner). A cover liner was then applied over the film to protect the surface under the desired film lamination heat and pressure.

[0175] DSC For DSC analysis, 10 mg film samples were subjected to a temperature increase of 10°C / min from room temperature to 350°C in a nitrogen atmosphere, and data on DSC onset temperature, peak temperature, and heat of reaction were collected.

[0176] DMA DMA analysis of the tensile modulus of the film samples was performed using a TA Instruments TA-Q800 flat-edge tension film fixture. The sample dimensions were approximately (20 × 8 × 0.3 mm). The samples were cured by heating from room temperature to 175 °C for 30 minutes, followed by a 1-hour soak at 175 °C.

[0177] DMA was performed at a heating rate of 5.0°C / min from -70°C to 300°C. The frequency was 10Hz and a strain amplitude of 5 microns was applied.

[0178] Referring to Figure 3, a DMA graph is shown showing that the cured film has low modulus and low warpage at room temperature and high modulus at high temperatures (e.g., 200°C), meeting the wire bonding process requirements for small die applications. The DMA graph also shows an additional tan δ (Tg, glass transition temperature) at high temperature (246.45°C), indicating that the bismaleimide resin has cured into an epoxy network, improving the high temperature properties of the cured composition.

[0179] Die Shear Strength Film samples were laminated onto silicon dies (3 x 3 mm) and placed on substrates (Cu leadframe substrate, Ag leadframe substrate, Au-plated Cu (PPF) leadframe substrate, BT substrate) in a die bonder at 120°C with 1 kg force for 5 seconds. The parts were cured from room temperature to 175°C over 30 minutes, followed by a 4-hour soak at 175°C. HDSS (hot die shear strength) data was obtained by shearing the die at 260°C. HWDSS (hot wet die shear strength) data was obtained by shearing the die at 260°C after 24 hours at 85°C / 85% RH. HWDSS was repeated three times.

[0180] The melt viscosity of the B-staged films was evaluated using a TA Instruments DHR2 rheometer at a heating rate of 5°C / min in N2. Sample dimensions were approximately 550 μm thick and 20 mm in diameter. Each formulation in Table 1 was subjected to several analyses, as described in the far left column. The results are summarized in Table 2 below.

[0181] [Table 2]

[0182] Referring to Table 2, Screening Sample 7, an epoxy / bismaleimide ("BMI") resin combination using a three-component curing agent package, exhibited higher adhesion to both the metal lead frame and BT substrate than the other screened samples. Screening Sample 7 also exhibited a cured film with a low modulus at room temperature due to reduced warpage, and a high modulus of 47 MPa at an elevated temperature of 200°C. This combination of physical properties is particularly attractive for the wire bonding process requirements of small die applications. DMA data also showed improved high-temperature properties, with tan δ (Tg, glass transition temperature) temperatures exceeding 200°C.

[0183] Example 2 Formulations according to the present invention were prepared by combining the ingredients set out in Table 3 below.

[0184] [Table 3]

[0185] Silica filler 1 is a micron-sized silica filler with an average particle size of less than 0.5 μm, and silica filler 2 is fumed silica. Epoxy resin 1 is a cycloaliphatic epoxy resin from Daicel. BMI 1 is a phenylmethane maleimide oligomer, BMI 2 is HOMIDE802 BMI resin, and BMI 3 is HOMIDE400 BMI resin. BMI 2 and BMI 3 are manufactured by Hos-Tec. CSR 1 is a PBd core-shell rubber and liquid BisA epoxy resin (40 wt%), and CSR 2 is a styrene-PBd copolymer core-shell rubber. Catalyst 1 is 4,4-DDS (4,4-diaminodiphenyl sulfone), catalyst 2 is a urea-type curing accelerator, and catalyst 3 is DICY (dicyandiamide).

[0186] Each of the inventive samples in Table 3 was subjected to multiple analyses. The results are summarized in Table 4 below. See also Figure 3 for a graphical representation of DMA, Figure 4 for a graphical representation of DSC, and Figure 5 for a graphical representation of melt viscosity. A low melt viscosity is advantageous for enhancing the wetting of the film to the substrate of the packaged BGA during the die attach process.

[0187] [Table 4]

[0188] Results show that the cured film material exhibits a low room temperature modulus (less than 2,500 MPa at 25°C) due to reduced warpage. DMA data also shows improved high temperature properties, with tan δ (Tg, glass transition temperature) temperatures exceeding 200°C. See also Figures 3 and 4 for graphical representations. The figures show that the film material exhibits a DSC onset temperature of 160°C-180°C, a DSC peak temperature of 180°C-210°C, and a heat of reaction exceeding 30 J / g.

[0189] The adhesive strength of each of the six inventive samples in Table 3 was also tested on four different substrates. Commercially available DDF1 is ATB100 and DDF2 is ATBF100E, both available from Henkel.

[0190] To eliminate artifacts caused by different test conditions, adhesion data was tested simultaneously and under the same conditions as the inventive samples. The results of the hot die shear strength and hot wet die shear strength evaluations are summarized in Table 5 below.

[0191] [Table 5]

[0192] The results show that these samples exhibit higher adhesion to multiple metal lead frames and BT substrates than existing Henkel commercial die attach films, both after curing at high temperature and after curing at high temperature and humidity.

Claims

1. (a) two or more resins selected from the group consisting of: (i) at least one maleimide-containing resin, nadimide-containing resin, or itaconimide-containing resin, and (ii) an epoxy resin; (b) core-shell particles comprising a polymeric material having elastomeric or rubbery properties surrounded by a shell of a non-elastomeric polymeric material; (c) optionally, an inorganic filler; (d) a hardener package comprising: 【Chemical 1】 (In the formula, R １ , R ２ , R ３ , and R ４ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms. 【Chemistry 2】 (In the formula, R １ , R ２ , R ３ , and R ４ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and 【Chemistry 3】 (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , and R ６ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms; R ２ and R ３ and R ５ and R ６ each taken together independently form a ring of 3 to 7 atoms; (e) one or more additives selected from the group consisting of adhesion promoters and film formers; A composition comprising:

2. After the composition forms a B-stage film, the B-stage film has the following physical properties: DSC has an onset temperature of 160°C to 180°C; DSC has a peak temperature of 180 ° C to 210 ° C. The heat of reaction exceeds 30 J / g, The composition of claim 1 , wherein

3. 10. The composition of claim 1, wherein after the composition forms a B-stage film, the B-stage film is laminated onto a 7 mm x 7 mm die and exposed to a temperature of about 175°C for about 1 hour, and the die is measured to exhibit warpage of less than about 100 μm.

4. 10. The composition of claim 1, wherein after the composition forms a B-stage film, the B-stage film is laminated onto a metal lead frame or BT substrate over a 3 mm x 3 mm die and exposed to a temperature of about 175°C for about 4 hours, after which the film adheres to the metal lead frame and exhibits an adhesion force of at least 3 kgf per die.

5. After the composition forms a B-stage film, the B-stage film has the following properties: A storage modulus of less than 2,500 MPa at 25°C as determined by dynamic mechanical analysis (DMA), and Glass transition temperature Tg exceeds 200°C, The composition of claim 1 , wherein

6. After the composition forms a B-stage film, the B-stage film has the following properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 100°C exceeds 50 MPa, and Glass transition temperature Tg exceeds 200°C, The composition of claim 1 , wherein

7. After the composition forms a B-stage film, the B-stage film has the following properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 150°C exceeds 20 MPa, and Glass transition temperature Tg exceeds 200°C, The composition of claim 1 , wherein

8. After the composition forms a B-stage film, the B-stage film has the following properties: DMA (Dynamic Mechanical Analysis) shows that the storage modulus at 200°C exceeds 10 MPa, and Glass transition temperature Tg exceeds 200°C, The composition of claim 1 , wherein

9. 10. The composition of claim 1, wherein after application to a metal lead frame and curing at a temperature of 260°C, the composition exhibits a die shear strength of >9 kgf / die on a copper metal lead frame and >5 kgf / die on a silver metal lead frame.

10. 10. The composition of claim 1, wherein the maleimide-, nadimide-, or itaconimide-containing resin (a)(i) is present in an amount of from about 5% to about 25% by weight.

11. 10. The composition of claim 1, wherein the epoxy resin (a)(ii) is present in an amount of about 1% to about 30% by weight.

12. 10. The composition of claim 1, wherein the resin (a) is present in a weight ratio of (a)(i):(a)(ii) of from about 0.3:1 to about 6:

1.

13. The composition of claim 1, wherein the core-shell particles (b) are present in an amount of about 5% to about 30% by weight.

14. 10. The composition of claim 1, wherein the core-shell particles (b) are present in a weight ratio to the resin (a) of (b):(a) of about 0.15:1 to about 0.95:

1.

15. The composition of claim 1, wherein the inorganic filler (c) is present in an amount of from greater than 0% to about 40% by weight.

16. The composition of claim 1, wherein the inorganic filler (c) is present in an amount of from greater than 0% to about 25% by weight.

17. 10. The composition of claim 1, wherein said inorganic filler (c) is present in a weight ratio to said resin (a) of (c):(a) from about 0.15:1 to about 0.90:

1.

18. 10. The composition of claim 1, wherein said inorganic filler (c) is present in a weight ratio to said core-shell particles (b) of (c):(b) of about 0.95:1 to about 5:

1.

19. 10. The composition of claim 1, wherein the curing agent package (d) comprises an aromatic urea, 4,4-diaminodiphenyl sulfone, and dicyandiamide.

20. 10. The composition of claim 1, wherein the curing agent package (d) comprises aromatic urea, 4,4-diaminodiphenyl sulfone, and dicyandiamide in a weight ratio of about 35 parts:100 parts:10 parts to about 40 parts:135 parts:15 parts.

21. 10. The composition of claim 1, wherein the hardener package (d) is present in a weight ratio to the resin (a) of (d):(a) from about 0.2:1 to about 0.35:

1.

22. the curing agent package (d) 【Chemistry 4】 The composition of claim 1 comprising:

23. The maleimide-, nadimide-, or itaconimide-containing resin (a)(i) is selected from the group consisting of: 【Chemistry 5】 (wherein n is 0 to 2) 【Chemistry 6】 wherein R is alkyl having 1 to 4 carbon atoms, phenyl, or alkylphenyl having 7 to 11 carbon atoms, and n is 1 to 12. 【Chemistry 7】 wherein R is alkyl or phenyl having 1 to 4 carbon atoms, x is diarylalkylene, and n is 1 to 2. 【Chemistry 8】 wherein n is 0, 1, 2, 3, 4, or 5; or 【Chemistry 9】 The composition of claim 1 selected from the group consisting of:

24. The epoxy resin (a)(ii) comprises: 【Chemistry 10】 【Chemistry 11】 wherein R is alkyl having 1 to 4 carbon atoms and n is 1 to 16. and 【Chemistry 12】 where x is alkylene having 1 to 4 carbon atoms and n is 0 to 75. The composition of claim 1 selected from the group consisting of:

25. 【Catalog 13】 (In the formula, R １ , R ２ , R ３ , and R ４ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms. 【Chemistry 14】 (In the formula, R １ , R ２ , R ３ , and R ４ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms, and 【Chemistry 15】 (In the formula, R １ , R ２ , R ３ , R ４ , R ５ , and R ６ are each independently selected from H, alkyl having 1 to 4 carbon atoms, alkoxy having 2 to 5 carbon atoms, and hydroxyalkyl having 1 to 4 carbon atoms; R ２ and R ３ and R ５ and R ６ may be taken together, independently of one another, to form a ring of 3 to 7 atoms. a hardener package including:

26. 【Catalog 16】 a hardener package including:

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