A thermosetting resin composition with low coefficient of thermal expansion and a prepreg and a metal foil laminate thereof

Abstract

The application discloses a thermosetting resin composition with low thermal expansion coefficient, and a prepreg and a metal foil laminated plate thereof, which comprises the following components in parts by weight: a prepolymer containing a benzoxazine resin: 49-89 parts; an epoxy resin: 10-50 parts; a phenolic compound: 1-10 parts; and the total weight of the above components is 100 parts. The application has the advantages of not only reducing the thermal expansion coefficient of the composition, but also realizing high Tg, high rigidity, low water absorption, high peeling strength and halogen-free flame retardation.

Description

Technical Field

[0001] This invention relates to the field of electronic materials, and in particular to a thermosetting resin composition with a low coefficient of thermal expansion and a prepreg laminate with a metal foil thereof. Background Technology

[0002] In recent years, semiconductors, widely used in electronic devices, communication equipment, and personal computers, have seen rapid development in terms of high integration, high functionality, and high-density assembly. Consequently, the requirements for the heat resistance and reliability of semiconductor packaging laminates are also increasing. Furthermore, the use of lead-free solder to address environmental concerns necessitates that laminates withstand the high-temperature environment of high-temperature reflow soldering.

[0003] Furthermore, the need to reduce the planar coefficient of thermal expansion of laminates is becoming increasingly urgent. This is because the coefficient of thermal expansion of semiconductor devices is only 3~6 ppm / ℃, which is smaller than that of typical semiconductor packaging laminates. If the difference in the coefficients of thermal expansion between the semiconductor device and the laminate is too large, it can cause warping of the semiconductor package under thermal shock, leading to poor connections between the semiconductor device and the laminate, and between the semiconductor package and the mounted printed circuit board.

[0004] To reduce the occurrence of warping defects, the thermal expansion coefficient in the planar direction of the laminate is usually reduced; or the glass transition temperature (Tg) of the laminate is increased to ensure that the laminate still has a high elastic modulus at high temperatures; or the rigidity of the laminate is increased (high modulus / high rigidity).

[0005] Increasing the glass transition temperature of laminates usually leads to a deterioration in moisture absorption, heat resistance, and formability due to the increased crosslinking density.

[0006] Generally speaking, there are several ways to reduce the coefficient of thermal expansion in the planar direction of laminates: 1. Fill with a large amount of inorganic filler, but as the content of inorganic filler increases, the resin composition becomes harder and more brittle, the mechanical drilling performance deteriorates, and the moldability of the composition also deteriorates; 2. Fill with organic fillers with rubber elasticity, but the flame retardant properties of organic fillers are generally poor, resulting in deterioration of flame retardant properties; 3. Use silicone rubber as an organic filler. Silicone rubber can provide a very excellent coefficient of thermal expansion, but the drilling processability is still poor.

[0007] Therefore, it is necessary to reduce the coefficient of thermal expansion of the resin composition itself, rather than achieving a low coefficient of thermal expansion through filling. Summary of the Invention

[0008] The purpose of this invention is to provide a thermosetting resin composition with a low coefficient of thermal expansion and its semi-cured sheet and metal foil laminate, which can not only reduce the coefficient of thermal expansion of the composition, but also achieve high Tg, high rigidity, low water absorption, high peel strength and halogen-free flame retardancy.

[0009] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0010] A thermosetting resin composition with a low coefficient of thermal expansion, characterized in that it comprises components in parts by weight: Prepolymer containing benzoxazine resin: 49–89 parts; Epoxy resin: 10-50 parts; Phenolic compounds: 1–10 parts; The total weight of the above components is 100 parts.

[0011] Preferably, the prepolymer containing benzoxazine resin is obtained by prepolymerization of a benzoxazine resin composition with a cyano group and a maleimide resin.

[0012] Preferably, the structural formula of the benzoxazine resin composition with a cyano group is shown in Formula I: Formula I; Where R represents methylene, , ,or One of them.

[0013] Preferably, the maleimide resin has the structural formula shown in Formula II: Formula II.

[0014] Preferably, the epoxy resin is selected from one or more of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, o-cresol epoxy resin, bisphenol A phenolic epoxy resin, phenolic epoxy resin, cresol phenolic epoxy resin, triphenylmethane epoxy resin, tetraphenylethane epoxy resin, biphenyl type epoxy resin, naphthalene ring type epoxy resin, dicyclopentadiene type epoxy resin, isocyanate type epoxy resin, aralkyl linear phenolic epoxy resin, alicyclic epoxy resin, glycidylamine type epoxy resin, glycidyl ether type epoxy resin, and glycidyl ester type epoxy resin.

[0015] Preferably, the epoxy resin is selected from one of naphthalene-type epoxy resin or biphenyl-type epoxy resin, wherein the structural formula of the naphthalene-type epoxy resin is shown in Formula III, and the structural formula of the biphenyl-type epoxy resin is shown in Formula IV. Formula III; Where p is an integer from 1 to 10; Formula IV; Where n is an integer from 1 to 10.

[0016] Preferably, the phenolic compound is selected from one or more of the following: phenolic resin, benzoxazine resin, bisphenol, monophenol, polyhydroxyphenol, hydroquinone, biphenyl phenol-type phenolic resin, biphenyl phenol-type naphthol resin, dicyclopentadiene phenol addition-type resin, phenol aralkyl resin, naphthol aralkyl resin, and trimethylolpropane resin.

[0017] Preferably, the thermosetting resin composition further includes inorganic fillers, wherein the amount of inorganic fillers added is 0-300% by weight of the thermosetting resin composition; Preferably, the inorganic filler is selected from one or more of non-metallic oxides, metal nitrides, non-metallic nitrides, inorganic hydrates, inorganic salts, metal hydrates, or inorganic phosphorus.

[0018] Preferably, the inorganic filler is selected from one or more of fused silica, crystalline silica, spherical silica, hollow silica, aluminum hydroxide, alumina, talc, aluminum nitride, boron nitride, silicon carbide, barium sulfate, barium titanate, strontium titanate, calcium carbonate, calcium silicate, mica, and glass fiber powder.

[0019] Preferably, the inorganic filler is silica, more preferably, it is surface-treated spherical silica. The surface treatment agent is a silane coupling agent, such as a silane coupling agent containing epoxy, amino, vinyl, acrylate, or allyl groups.

[0020] Preferably, the inorganic filler has a median particle size of 0.1 to 15 micrometers. More preferably, the filler has a median particle size of 0.1 to 1.0 micrometers.

[0021] Preferably, the thermosetting resin composition further includes an elastomer, the amount of which is 0% to 50% by weight of the thermosetting resin composition, and the elastomer is selected from one or more of styrene elastomers, methacrylate elastomers, and silicone elastomers.

[0022] The styrene elastomers are selected from one of the following: H1041, H1043, H1051, H1052, H1053, H1221, P1500, P2000, M1911 or M1913 from Asahi Kasei Corporation of Japan; or 8004, 8006, 8076, 8104, V9827, 2002, 2005, 2006, 2007, 2104, 7125, 4033, 4044, 4055, 4077 or 4099 from Kuraray.

[0023] The methacrylates are selected from one of the following: Arkema's M51, M52, M22 or D51N, Kuraray's LA-2330, Nagase's SG-P3 series or SG-80 series.

[0024] The silicone elastomer is selected from one of the following: X-40-2670, R-170S, X-40-2705, X-40-2701, KMP-600, KMP-605, X-52-7030, DOW's AY-42-119, EP-2600, EP-2601, EP-2720, TMS-2670, EXL-2315, or EXL-2655, manufactured by Shin-Etsu Chemical Co., Ltd.

[0025] A semi-cured sheet is prepared by dissolving a resin composition, inorganic filler and curing accelerator in a solvent to obtain an adhesive solution, impregnating the adhesive solution onto a fiberglass cloth, and then curing the adhesive solution by baking at 100~180℃ for 1~10 minutes.

[0026] Preferably, the curing accelerator is selected from one or more of imidazole compounds, organometallic carboxylates, free radical initiators, tertiary amine compounds, or organophosphorus compounds.

[0027] Preferably, the solvent is selected from one or more of acetone, butanone, toluene, N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol methyl ether, and propylene glycol methyl ether.

[0028] A metal foil laminate is obtained by stacking prepregs, covering one or both sides of them with metal foil, and pressing them at a pressure of 0.5-5 MPa and a temperature of 180-250°C for 2-4 hours.

[0029] Preferably, the number of the prepreg sheets can be determined by the required thickness of the metal foil laminate, and one or more sheets can be used. The metal foil can be copper foil or aluminum foil, and its material is not limited; the thickness of the metal foil is also not particularly limited, such as 5 micrometers, 8 micrometers, 12 micrometers, 18 micrometers, 35 micrometers or 70 micrometers.

[0030] In summary, the present invention has the following beneficial effects: 1. The thermosetting resin composition of the present invention contains benzoxazine resin and phenolic compounds. Compared with benzoxazine resin alone, the combination of the two makes it easier to achieve high residual carbon rate, high limiting oxygen index and low smoke density. The intrinsic flame retardancy can be achieved by using the thermosetting resin composition of the present invention, which can achieve UL94V0 flame retardancy, thereby reducing the water absorption rate of the system and improving the system's resistance to damp heat.

[0031] 2. The epoxy resin in the thermosetting resin composition of the present invention can act as a reactive diluent for benzoxazine resin, making the curing reaction more complete and uniform. In addition, the epoxy resin can improve the adhesion of the system and the peel strength with copper foil. Furthermore, the phenolic compound can greatly reduce the ring-opening temperature of benzoxazine to below 200°C, thus overcoming the disadvantage of the curing temperature of benzoxazine resin itself, which is as high as 220°C or more. The reaction window of the composition is much wider than that of a single benzoxazine resin system.

[0032] 3. The epoxy resin in the thermosetting resin composition of the present invention can improve the brittleness of the single benzoxazine system and toughen the system, while the phenolic compound can improve the heat resistance and rigidity of the system, so that the material generated by the reaction of the resin composition has both high toughness and high rigidity.

[0033] 4. The thermosetting resin composition of the present invention contains phenolic compounds, benzoxazine rings, maleimide, and cyano groups, and has properties similar to BT resin. The phenolic compounds can promote the ring-opening of benzoxazine rings. After the benzoxazine resin rings open, it can catalyze the complete reaction of maleimide groups. Furthermore, the hydroxyl groups and tertiary amines generated after the benzoxazine rings open can promote the construction of triazine rings by cyano groups, further reducing the reaction temperature of cyano groups and lowering the curing temperature of the curing system to 180-220°C, breaking the conventional practice that cyano resins require high-temperature curing. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below. These embodiments do not constitute a limitation on the present invention.

[0035] Table 1 below lists the manufacturers and models of the required raw materials: Table 1

[0036] According to the component contents shown in Table 2 below, the prepolymer containing benzoxazine resin, epoxy resin, phenolic resin, filler, elastomer, curing accelerator, and an appropriate amount of methyl ethyl ketone solvent were stirred and mixed evenly to obtain a glue solution with a solid content of 65%. The glue solution was impregnated and coated onto E-glass fiber cloth (7628), and baked in an oven at 160°C for 5 minutes to obtain a prepreg.

[0037] Table 2

[0038] Preparation of performance evaluation sample metal foil laminates: The prepreg obtained above is placed with a 12-micron copper foil on each side, and then pressed in a vacuum hot press to obtain a metal foil laminate. The specific pressing process involves pressing at 2.5 MPa pressure and 180~230℃ for 4 hours.

[0039] The prepregs and metal foil laminates prepared in all Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The performance test methods are as follows: (1) Glass transition temperature Tg (°C): DMA tester, sample size 40 mm 3mm 0.2mm, temperature rise rate 10℃ / min, from 30℃ to 350℃.

[0040] (2) Y-axis CTE (ppm / ℃): TMA tester, sample size 30mm 4mm 0.2 mm, temperature rise rate 10℃ / min, from 30℃ to 300℃; measure the thermal expansion coefficient in the surface direction at 50~130℃; the measurement direction is taken as the longitudinal direction (warp) of the glass fiber cloth of the laminate.

[0041] (3) Heat resistance of tinning after damp heat treatment: Take three 10cm×10cm samples with a thickness of 0.80mm and metal foil removed on both sides, dry them at 100℃ for 2 hours, then treat them at 121℃ and 2 atmospheres for 5 hours using a pressure cooker tester, and immerse them in tin at 288℃ for 20s. Visually observe whether there is delamination. If delamination occurs in 0, 1, 2 and 3 of the three samples, record them as 0 / 3, 1 / 3, 2 / 3 and 3 / 3 respectively.

[0042] (4) Water absorption rate (%): Tested according to IPC-TM-650 2.6.2.1 method.

[0043] (5) Modulus retention (%): DMA tester, sample size 40mm 3mm 0.2 mm, temperature rise rate 10℃ / min, from 30℃ to 320℃. Modulus retention rate = Young's modulus (260℃) / Young's modulus (50℃) 100%.

[0044] (6) Peel strength (PS, N / mm): The peel strength of the metal capping layer was tested according to the experimental conditions of “after thermal stress” in IPC-TM-650 2.4.8.

[0045] (7) Flame retardancy: determined by UL94 method.

[0046] Table 3 Performance Table

[0047] As shown in the table above, compared with Examples 1-5, Comparative Examples 1 and 2, which used bismaleimide resin, cyanate ester resin, naphthalene ring epoxy resin, and epoxy resin curing agent, showed deterioration in Tg, X / Y axis CTE, modulus retention, peel strength, and flame retardancy. In contrast, the embodiments of the present invention simultaneously possess high heat resistance, high resistance to humid heat, low X / Y axis CTE, low water absorption, high modulus retention, high peel strength, and excellent flame retardancy.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A thermosetting resin composition with a low coefficient of thermal expansion, characterized in that, Including components counted in parts by weight: Prepolymer containing benzoxazine resin: 49–89 parts; Epoxy resin: 10-50 parts; Phenolic compounds: 1–10 parts; The total weight of the above components is 100 parts.

2. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 1, characterized in that: The prepolymer containing benzoxazine resin is obtained by prepolymerizing a benzoxazine resin composition with a cyano group and a maleimide resin.

3. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 2, characterized in that: The structural formula of the benzoxazine resin composition with a cyano group is shown in Formula I: Formula I; Where R represents methylene, , ,or One of them.

4. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 2, characterized in that: The structural formula of the maleimide resin is shown in Formula II: Formula II.

5. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 1, characterized in that: The epoxy resin is selected from one or more of the following: bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, phosphorus-containing epoxy resin, nitrogen-containing epoxy resin, o-cresol epoxy resin, bisphenol A phenolic epoxy resin, phenolic epoxy resin, cresol phenolic epoxy resin, triphenylmethane epoxy resin, tetraphenylethane epoxy resin, biphenyl type epoxy resin, naphthyl ring type epoxy resin, dicyclopentadiene type epoxy resin, isocyanate type epoxy resin, aralkyl linear phenolic epoxy resin, alicyclic epoxy resin, glycidylamine type epoxy resin, glycidyl ether type epoxy resin, and glycidyl ester type epoxy resin.

6. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 1, characterized in that: The phenolic compounds are selected from one or more of the following: phenolic resin, benzoxazine resin, bisphenol, monophenol, polyhydroxyphenol, hydroquinone, biphenyl phenol-type phenolic resin, biphenyl phenol-type naphthol resin, dicyclopentadiene phenol addition-type resin, phenol aralkyl resin, naphthol aralkyl resin, and trimethylolpropane resin.

7. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 1, characterized in that: The thermosetting resin composition further includes inorganic fillers, wherein the amount of inorganic fillers added is 0-300% by weight of the thermosetting resin composition; The inorganic filler is selected from one or more of the following: non-metallic oxides, metal nitrides, non-metallic nitrides, inorganic hydrates, inorganic salts, metal hydrates, or inorganic phosphorus.

8. The thermosetting resin composition with a low coefficient of thermal expansion according to claim 1, characterized in that: The thermosetting resin composition further includes an elastomer, wherein the amount of the elastomer added is 0% to 50% by weight of the thermosetting resin composition, and the elastomer is selected from one or more of styrene elastomers, methacrylate elastomers, and silicone elastomers.

9. A semi-cured sheet, characterized in that: The thermosetting resin composition with low thermal expansion coefficient as described in any one of claims 1 to 8, inorganic filler and curing accelerator are dissolved in a solvent to obtain an adhesive solution, the adhesive solution is impregnated on a fiberglass cloth, and then the adhesive solution is cured by baking at 100 to 180°C for 1 to 10 minutes. The curing accelerator is selected from one or more of imidazole compounds, organometallic carboxylates, free radical initiators, tertiary amine compounds, or organophosphorus compounds.

10. A metal foil laminate, characterized in that: After stacking the prepregs as described in claim 9, metal foil is applied to one or both sides of the prepregs and then hot-pressed to form a metal foil laminate.

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