CN101215358B - A kind of prepolymer and thermosetting resin composition made by using the prepolymer - Google Patents

Abstract

The invention provides a prepolymer, which takes 4- (N-Maleimide Phenyl) Glycidyl Ether (MPGE) epoxy resin and 4, 4' -diaminodiphenylmethane Bismaleimide (BMI) as reactants, a free radical initiator initiates reaction in a solvent, a polymerization inhibitor is added after the reaction, and the molar ratio of the BMI to the MPGE is 0.05 to 0.5; the amount of the initiator is 0.01 to 0.15 percent of the total mole amount of the reactant monomer; the dosage of the solvent is 50 to 70 percent of the total weight of the reactants; the amount of polymerization inhibitor used is from half to one time the molar amount of initiator used. The prepolymer can be used to prepare high performance thermosetting resin compositions corresponding to the requirements of electronic components and Integrated Circuit (IC) packaging.

Description

A kind of prepolymer and thermosetting resin composition made by using the prepolymer

technical field

The invention relates to a prepolymer and a high-performance thermosetting resin composition prepared by using the prepolymer corresponding to the packaging requirements of electronic components and integrated circuits (IC).

Background technique

The increasing demand for electronic information products in light, thin, small and high density drives the development of printed circuit boards in the direction of thinner lines and micro-hole technology. Coupled with the continuous progress of miniaturized surface mount technology, the demand for high-end IC packaging substrates continues to increase.

The traditional IC packaging uses a lead frame as a carrier for the IC conduction line and supporting the IC, and it connects pins on both sides or around the lead frame. With the development of IC packaging technology, the number of pins has increased (more than 300 pins), the wiring density has increased, and the number of substrate layers has increased, making traditional QFP (Quad Flat Package, small square planar package) and other packages Form is limited in its development. In the mid-1990s, a new IC packaging form represented by BGA (Ball Grid Array Package) and CSP (Clip Scale Package, chip-level packaging) came out, and a semiconductor chip package was also produced. A new carrier is needed, which is the IC package substrate (IC Package Substrate, also known as IC package substrate).

In recent years, IC packaging substrates in the form of BGA, CSP, and FC (Flip Chip) have rapidly expanded in application fields and become popular. The world's major producing countries and regions engaged in the packaging manufacturing industry are launching fierce competition in the packaging substrate market. The focus of this competition is mainly manifested in the full use of high-density multilayer substrate technology in IC packaging and the reduction of manufacturing costs of packaging substrates.

The development of substrate materials for IC packaging substrates (also known as IC packaging substrates) is a very important topic at present. With the development of IC packaging in the direction of high frequency and low power consumption, IC packaging substrates will be improved in important properties such as low dielectric constant, low dielectric loss factor, and high thermal conductivity. An important direction in the research and development of IC packaging substrates is the thermal connection technology of the substrate-effective thermal coordination and integration such as heat dissipation. Electronic components consume power and generate a large amount of heat, which will cause the temperature of the device to rise. Generally speaking, for every 18°C increase in temperature, the possibility of device failure increases by 2 to 3 times. Therefore, it is particularly important to improve the thermal conductivity of the packaging material to solve the heat dissipation problem, so as to ensure that the circuit works normally within the operating temperature range.

The IC packaging substrate also needs to solve the problem of inconsistent thermal expansion coefficient with the semiconductor chip. Even if it is a build-up multilayer board suitable for making microcircuits, there is a problem that the thermal expansion coefficient of the insulating substrate is generally too large (generally, the thermal expansion coefficient is 60ppm/°C). The thermal expansion coefficient of the substrate reaches about 6ppm, which is close to that of the semiconductor chip, which is indeed a "difficult challenge" for the manufacturing technology of the substrate.

The development of IC packaging design and manufacturing technology has put forward stricter requirements for the substrate materials used in it. This is mainly reflected in the following aspects: 1) High Tg and high heat resistance corresponding to lead-free solder; 2) Low dielectric loss factor characteristics that need to reduce signal transmission loss; 3) Low dielectric corresponding to high speed Constant; 4) Low warpage (improvement of substrate surface flatness); 5) Low moisture absorption; 6) Low thermal expansion coefficient, making the thermal expansion coefficient close to 6ppm; 7) Low cost of IC packaging substrate; 8) Low-cost built-in components; 9) High-strength performance at high temperature; 10) Low-cost, environmentally friendly substrate material suitable for lead-free reflow soldering process.

Substrates used in IC packaging are mostly made of organic resins. Many resins have been used in this field, such as epoxy resin, acrylate resin, cyanate resin and bismaleimide-triazine resin (BT).

Epoxy resin is the most commonly used type of resin. It has the advantages of easy processing, good adhesion to various substrates, high chemical and corrosion resistance, and excellent mechanical properties. However, the performance of epoxy resin at high temperature is unsatisfactory, mainly due to the high dielectric constant (such as the dielectric constant of E-679F, an epoxy resin-based package substrate developed by Hitachi Chemical Co., Ltd. at frequencies of 1MHz and 1GHz. The constants are 4.85 and 4.53 respectively) and the water absorption rate is relatively large. Epoxy resins are usually cured with amines and acid anhydrides, and the cured materials inevitably contain a large number of hydrophilic groups such as hydroxyl groups, resulting in high water absorption of the materials. Therefore, under high temperature and high humidity conditions, the cured epoxy resin is very sensitive to water.

Compared with traditional epoxy resins, the performance of cyanate resins has been improved to a certain extent. In order to obtain high crosslink density and high glass transition temperature (Tg) with lower dielectric properties, cyanate ester resins are usually required. However, cyanate resin itself has disadvantages such as high price, high brittleness after curing, and high water absorption.

The other most important resin is bismaleimide, which is characterized by excellent physical properties under high temperature and high humidity conditions, and stable electrical properties (no fluctuations) in a wide temperature range. These properties make bismaleimides particularly suitable for use in advanced composite materials and electrical and electronic fields. Bismaleimide has good hygrothermal properties up to 230-250°C. However, bismaleimides are generally insoluble in traditional organic solvents and thus difficult to process. In addition, bismaleimide also has disadvantages such as too harsh curing conditions and too high brittleness after curing of the resin, which easily produces microcracks under thermal shock.

Typically, bismaleimides are used in combination with cyanate esters to obtain what are commonly referred to as BT resins. This type of resin was first developed and patented by Japan's Mitsubishi Gas Co., Ltd. (US Patent No. 4,110,364).

Bismaleimide-triazine resin (abbreviated as BT resin) is a high-quality product obtained by copolymerization of cyanate resin (CE) with -OCN and bismaleimide resin (BMI) at 170-240 ° C. Polymer resin, finally obtained is a high heat-resistant high polymer composed of triazine ring, imide ring and other nitrogen-heterocyclic structures. The cured product of this BMI/CE copolymer not only has the impact resistance, electrical insulation (mainly manifested in low ε, low tanδ) and process operability of BMI resin, but also improves the water resistance of cyanate resin. And maintain the high heat resistance that both have.

Due to the substrate material made of BT resin, it is excellent in PCT (Pressure Cooker Test, pressure cooker test) resistance, metal ion migration resistance, heat resistance, dielectric properties, heat and humidity resistance, and high temperature impact resistance. , especially the mechanical properties at high temperature (mainly including high temperature flexural strength, elastic modulus, copper foil bonding strength and surface hardness, etc.), compared with other resin substrate materials (such as general epoxy resin, polyimide Substrate materials made of resin, polyphenylene ether resin, etc.) have more prominent advantages. Therefore, in the application of IC packaging substrates, the insulation reliability and processability of chip mounting and high-density wiring lines are improved, so that the BT resin manufacturing Substrate materials account for a large proportion of various substrate materials used in IC packaging.

However, the cross-linking density of BT resin after polymerization is large, and the structure of the triazine ring in the molecule is highly symmetrical and the degree of crystallinity is high, which makes the cured product relatively brittle, and the cyanate resin (CE) used, due to its complex synthesis Therefore, increasing toughness and processability and reducing costs have become the focus of many derivative patents since the publication of the BT resin patent of Mitsubishi Gas Chemical Company in August 1978. There are so many patents in this area: US4456712, US4683276, US4749760, US4847154, US4902778, US4927932, US4996267, US6534179, US6774160, JP1197559, JP7070316, JP200129468, JP2006169317, JP2009602, etc.

In addition, epoxy resin/bismaleimide system, BT resin, etc. cannot form stable solutions in various low boiling point solvents. In order to facilitate impregnation, it is usually necessary to use high-boiling strong polar solvents such as dimethylformamide (DMF) and N-methylpyrrolidone to aid dissolution. The use of solvents such as DMF and N-methylpyrrolidone will accelerate the reactivity of the resin system and seriously affect the gel time of the resin composition, which will bring certain problems to the gluing process.

Directly use 4-(N-maleimide phenyl) glycidyl ether (MPGE) epoxy resin with DICY or phenolic resin as curing agent to make copper-clad laminates. The glass transition temperature can only reach about 170°C. To further increase the glass transition temperature, it needs to be modified with bismaleimide. If it is just a simple blending, due to the poor compatibility of the two, phase separation occurs, and it is not suitable for the impregnation process, so pre-polymerization treatment is required.

In view of this, the present inventor studies this, aims at developing a kind of prepolymer that can be applied to manufacture high-performance thermosetting resin composition, and utilizes this prepolymer to make corresponding to electronic component and integrated circuit (IC) The high-performance thermosetting resin composition required for encapsulation makes it inexpensive, and does not require the use of high-boiling polar solvents such as DMF and N-methylpyrrolidone, but can be dissolved in common low-boiling non-polar solvents such as acetone, toluene, di Form stable solutions in methyl chloride, methyl ethyl ketone or methyl isobutyl ketone, resulting in this case.

Contents of the invention

The purpose of the present invention is to provide a high heat-resistant prepolymer, which can be used to prepare a high-performance thermosetting resin composition corresponding to the packaging requirements of electronic components and integrated circuits (IC).

Another object of the present invention is to provide a cheap new thermosetting resin composition made of the prepolymer, the resin composition forms a stable homogeneous solution in a low-boiling solvent, and the copper clad laminate material manufactured with it With high glass transition temperature (Tg), excellent dielectric properties, low expansion coefficient, low water absorption, high thermal shock resistance and excellent thermal conductivity, it is suitable for substrate materials for electronic components and integrated circuit (IC) packaging .

A kind of prepolymer provided by the invention, with 4-(N-maleimide phenyl) glycidyl ether (MPGE) epoxy resin and 4,4'-diaminodiphenylmethane type bismaleimide Amine (BMI) is the reactant, the reaction is initiated by a free radical initiator in the solvent, and a polymerization inhibitor is added after the reaction, the molar ratio of BMI to MPGE is 0.05 to 0.5; the amount of the initiator is the total molar amount of the reactant monomer 0.01%-0.15% of the total weight of the solvent; the amount of the solvent is 50%-70% of the total weight of the reactant; the amount of the inhibitor is half to one time of the molar amount of the initiator used.

The above-mentioned solvent is one or more of acetone, toluene, methylene chloride, butanone, methyl isobutyl ketone, and cyclohexanone.

The above-mentioned initiator is an azo initiator, the reaction temperature is controlled at 60-90° C., and the reaction time is controlled at 10-60 minutes.

The above-mentioned initiator is a peroxide initiator, the reaction temperature is controlled at 100-130° C., and the reaction time is 10-60 minutes.

The aforementioned polymerization inhibitors are quinones, aromatic nitro compounds, or variable-valence metal salts, electrophilic substances, or electron-donating substances such as phenols and amines.

A more preferred molar ratio of BMI to MPGE is 0.25 to 0.475.

The more preferable dosage of the initiator is 0.05%-0.10% of the total molar amount of reactant monomers.

The more preferable amount of solvent is 60%-70% of the total weight of reactants.

The thermosetting resin composition made of the prepolymer provided by the present invention comprises the following components: (1) the prepolymer provided by the present invention accounts for 1.90-34.5% of the solid weight of the composition; (2) at least one Styrene-maleic anhydride oligomers with a molecular weight range of 1400-50000, accounting for 17.5%-47.0% by weight of the solids of the composition; (3) at least one filler, accounting for 20%-60% by weight of the solids of the composition (4) at least one solvent, the amount of solvent added accounts for 20%-50% of the weight of the composition. (5) At least one flame retardant that can be used in the copper clad laminate industry.

The optimum molecular weight range of the styrene-maleic anhydride oligomer is 1400-10000.

The optimal ratio of the styrene-maleic anhydride oligomer to the weight of the solid content of the composition is 22.5%-38.0%.

The fillers are silica (including crystalline, fused and spherical silica), alumina, mica, talc, boron nitride, aluminum nitride, silicon carbide, diamond, calcined clay, alumina, nitrogen One or a combination of aluminum fibers or glass fibers.

The optimal proportion of the filler is 30%-50% by weight of the solid content of the composition.

The solvent includes one or a mixture of acetone, methyl ethyl ketone (butanone, MEK), methyl isobutyl ketone, cyclohexanone, toluene or methylene chloride.

(1) 4-(N-maleimide phenyl) glycidyl ether (MPGE) epoxy resin

Maleimide can improve the high temperature resistance of epoxy resin. The way of modification is to use polybismaleimide and epoxy resin to react and crosslink to form an interpenetrating network (IPN); to cure epoxy resin with a curing agent containing imide groups; to use thermoplastic polyimide or There are 3 kinds of polyimide functional groups and epoxy resin blends. The main disadvantage of these methods is that the imide component has poor compatibility with epoxy resin, and it is difficult to process and shape. On the other hand, the work of introducing imide groups into the main chain of epoxy resin is a hot area of research now. Usually polyimide or imide compound is added to the epoxy matrix, or used as a curing agent to improve the thermal stability and flame retardancy of the epoxy resin.

Chuan-Shao Wu et al. used triphenylphosphine and methyl ethyl ketone as catalyst and solvent for the first time to make a simple addition reaction between maleimide with hydroxyl group and epoxy group to obtain an interpenetrating network structure. The glass transition temperature of the epoxy cured product modified by maleimide increased from 369°C to 381-386°C, the residual carbon rate at 800°C in N ₂ atmosphere was up to 27.3%, and the LOI value was 29.5. The 4-(N-maleimide phenyl) glycidyl ether (MPGE) epoxy resin synthesized by Ying-Ling Liu et al. was cured with DDM, DICY and DEP (diethyl phosphite) to obtain the cross-linked network . In _N2 atmosphere, the 5% weight loss temperature can reach 355°C, the complete decomposition temperature (IPDT) can reach 2287°C, and the residual carbon rate can reach 60.38% at 800°C; in air, the 5% weight loss temperature can reach 348°C, and the complete decomposition temperature can reach 669 ℃, 800 ℃ residual carbon rate reached 11.01%, LOI value up to 48.O.

(2) 4,4'-diaminodiphenylmethane type bismaleimide (BMI)

4,4'-diaminodiphenylmethane type bismaleimide (BMI) is a main species of polyimide polyimide, which is heated by 4,4-diaminobenzenediphenylmethane and diamine Or it can be synthesized under the action of catalyst. Bismaleimide is a thermosetting resin, which forms a polymer with a high degree of crosslinking after thermal polymerization. This polymer has good heat resistance, flame resistance and insulation, and the price is moderate. Therefore, it is generally believed that BMI is an ideal resin matrix for the manufacture of heat-resistant structural materials and insulating materials, and it is a multi-purpose organic compound with bifunctional groups. The high electrophilicity of its double bond makes it easy to react with various nucleophiles, and its unique heat resistance is determined due to its five-membered heterocyclic structure.

(3) Free radical initiator

Under the action of initiator and heat, the mixture of BMI and MPGE undergoes three competing reactions: their respective homopolymerization and copolymerization between BMI and MPGE. Therefore, the proportion of reactants, the type and amount of initiator, the type and amount of solvent, reaction temperature, and reaction time are important factors affecting the reaction.

Ratio of reactants: the appropriate molar ratio of BMI to MPGE can be from 0.05 to 0.5, and the better molar ratio is 0.25-0.475.

The type and amount of initiator: the appropriate type of initiator should be selected according to the needs, so that the free radical formation rate and polymerization rate are moderate. If the decomposition activation energy of the initiator is too high or the half-life is too long, the decomposition rate will be too low, which will prolong the polymerization time; but if the activation energy is too low and the half-life is too short, the initiation will be too fast, it will be difficult to control the temperature, and it may cause implosion, which will Prolong the polymerization time or end the premature decomposition of the initiator, and stop the polymerization when the conversion rate is very low. Therefore, an initiator whose half-life is the same order of magnitude or equivalent to the polymerization time should generally be selected. Usually, choosing a compound initiator can make the reaction proceed at a more uniform speed. Commonly used initiators are azo (such as azobisisobutyrocyanide) and peroxides (such as dicumyl peroxide). The amount of initiator used will affect the reaction rate and molecular weight. If the amount of initiator is too low, the conversion rate of the monomer will be low; if the amount is too large, the growth rate of free radicals will increase, which will cause the concentration of instantaneous free radicals in the reactant system to be too concentrated, thereby causing aggregation. A suitable initiator dose is 0.01%-0.15% (mol fraction) of the total amount of monomers. When the initiator dose is 0.05%-0.10% (mol fraction), the prepared prepolymer is soluble in common solvents such as acetone, butanone, etc. A stable homogeneous solution can be formed.

Reaction conditions: the control of reaction temperature and reaction time. If the reaction temperature is low, the required reaction time is long; while the reaction temperature is high, the reaction time can be shorter. However, if the reaction temperature is too high and the reaction is too intense, implosion may occur. If an azo initiator such as azobisisobutylcyanide is selected, the reaction temperature should be controlled at 60-90°C, and the reaction time should be controlled at 10-60min. If a peroxide initiator is selected, the reaction temperature should be increased to 100-130°C.

(4) Solvent used in prepolymerization

The type and amount of solvent: when a good solvent is selected, it is a homogeneous polymerization. If the amount of solvent is appropriate, the monomer concentration is not high, and it is possible to eliminate the automatic acceleration effect. However, if a precipitant or a poor solvent is selected, the automatic acceleration is significant. The reaction is not well controlled. Usually, one or more of acetone, toluene, methylene chloride, butanone, cyclohexanone or methyl isobutyl ketone is selected as the solvent. The amount of solvent is preferably 50%-75% of the total weight of the entire reaction mixture, and the recommended amount of solvent is 60%-70%.

(5) Inhibitor

After the MPGE/BMI system is prepolymerized at a certain temperature, in order to ensure the stability of the prepolymer during storage, it is necessary to add an appropriate amount of polymerization inhibitor. Since the same inhibitor has different inhibitory effects on different monomers, the appropriate inhibitor should be selected according to the type of monomer used. The general selection principles are as follows: 1) For monomers with electron-donating substituents, such as styrene, vinyl acetate, etc., quinones, aromatic nitro compounds or variable-valence metal salts can be used as electrophilic substances as polymerization inhibitors; 2) For monomers with electron-withdrawing substituents, such as acrylonitrile, acrylic acid, methyl acrylate, etc., electron-donating substances such as phenols and amines can be used as polymerization inhibitors; 3) In order to avoid side reactions, avoid Inhibitor and initiator form an oxidation-reduction system to increase the reaction rate.

The present invention selects quinones, aromatic nitro compounds or variable-valence metal salts as electrophilic substances or phenols, amines and other electron-donating substances. The amount of the polymerization inhibitor is generally half to one time (by moles) the amount of the initiator used.

(6) Styrene-maleic anhydride oligomer

The thermosetting resin composition of the present invention includes one or more styrene-maleic anhydride (SMA) oligomers. SMA can further improve the thermal and electrical properties of cured polymers and their articles. There are two main types of SMAs that are commercially available. One type is high molecular weight copolymers (molecular weight over 100,000, even as high as one million). This type of SMA is actually a thermoplastic polymer and is not suitable for making prepregs. In addition, because of its low anhydride content (generally In the range of 5-15%), it is not suitable as a cross-linking agent for epoxy resins. Another type of SMA has a molecular weight of 1,400 to 50,000 and an acid anhydride content higher than 15%. This type of SMA is intended to be used in the present invention. The recommended molecular weight range for SMA oligomers is 1400-10000. Such as commercially available SMA1000, SMA2000, SMA3000, SMA4000, the molar ratios of styrene and maleic anhydride in these oligomers are 1:1, 2:1, 3:1, 4:1 respectively, and the molecular weight range is 1400 to 2000. One or their mixtures of the above SMA copolymers are all suitable to be formulated into the resin composition of the present invention.

The amount of SMA in the resin composition is 17.5-47.0 parts by weight based on 100 parts by weight of the solid content of the composition, and the recommended amount is 22.5-38.0 parts by weight.

(7) filler

Fillers can improve the chemical and electrical properties of the cured resin, such as reducing the coefficient of thermal expansion (CTE), increasing the modulus, and accelerating heat transfer, etc. Silica (including crystalline, fused and spherical silica), alumina, mica, talc, boron nitride, aluminum nitride, silicon carbide, diamond, calcined clay, alumina, aluminum nitride fiber and Glass fibers and the like can be used as additives for polymer-based composite packaging materials. By selecting different types or shapes of inorganic substances such as particles, spheres or fibers, and adjusting their content, distribution and combination with the polymer interface, the performance of composite materials can be adjusted within a certain range. Among them, calcined clay or fused silica or silane-treated silica or aluminum nitride or alumina can be considered as the first choice for the filler used.

The filler used in the present invention accounts for 20-60% of the total weight of the solid composition, and the recommended proportion is 30%-50%.

(8) Solvents used in the process of synthesizing resins

In the present invention, in addition to the need to use a solvent in the prepolymerization process, one or more solvents can also be used to improve the solubility of the resin, control the viscosity of the resin, and ensure that the components of the resin composition are in a homogeneous state or a suspended dispersion state . In principle, any solvent associated with thermosetting resin systems can be used. Suitable solvents include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, toluene, dichloromethane, etc. or mixtures thereof. The choice of solvent often depends on the resin curing system used and the way the resin is cured. If hot air curing is used, ketone solvents are generally used, and if infrared curing is used, a mixed solvent of toluene and ketones is usually required. The solvent is used in an amount of 20%-50% by weight of the whole composition.

(9) Flame retardant

One or more flame retardants can be added to the resin composition of the present invention. Any flame retardant used in the copper clad laminate industry can be used in the present invention. Applicable flame retardants may include, but are not limited to: halides of glycidyl ether type difunctional alcohols, bisphenol A, bisphenol F, polyvinyl phenol or phenol, cresol, alkyl phenol, etc. Halides, inorganic flame retardant materials, such as antimony trioxide, red scale, zirconium hydroxide, barium metaborate, aluminum hydroxide, magnesium hydroxide, phosphorus flame retardants, such as tetraphenylphosphine, tri(o-cresyl phosphate) ) diphenyl ester, triethyl phosphate, cresyl diphenyl phosphate, acid phosphate, nitrogen-containing phosphate (ester) compounds and halogen-containing phosphate, etc.

Another class of alternative flame retardants are bromine-containing compounds with the following structures:

When bromine-containing compounds or bromine-containing epoxy resins or bromine-containing Novella resins are used as flame retardants, the amount of flame retardants is such that the bromine content accounts for 8%-30% of the total weight of the solid resin, and the maximum The best bromine content is 10%-20%.

The present invention can also increase following each composition, and its principle is as follows:

(10) Accelerator

One or more accelerators may be added to the resin composition to harden the resin and increase the rate at which the resin hardens. The accelerator selected can be any accelerator known to increase the rate of hardening of thermosetting resins. Suitable accelerators are imidazoles, especially alkyl-substituted imidazoles, such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-ethyl-4-phenylimidazole, etc. . Other suitable accelerators include various quaternary amines such as benzyldimethylamine, 4,4'- and 3,3'-diaminodiphenylsulfone. The suggested accelerator is 2-ethyl-4-methylimidazole. The amount of accelerator used depends on the following factors: type of epoxy resin used, type of hardener, type of accelerator, etc. Using an excess of accelerator will result in an overreactive resin system. A skilled artisan can easily determine the amount of accelerator used to make the resin sufficiently reactive for impregnation to make a prepreg. Generally speaking, the amount of the accelerator is between 0.001% and 2% of the total weight of the epoxy resin and the hardener, and in most cases, the value ranges from 0.01% to 0.05%. The resin gelation time depends on the type and amount of accelerator, the type and amount of solvent, the type and amount of filler, and the type of prepreg to be manufactured (glass cloth type).

(11) toughening agent

The resin composition of the present invention may include one or more toughening agents. The purpose of adding the toughening agent to the resin composition is to improve the drillability and thermal reliability of the printed circuit board. Suitable tougheners include methyl methacrylate/butadiene/styrene copolymers, styrene/butadiene copolymers, polymethacrylate/butadiene/styrene core-shell particles, polydiene Methylsiloxane core-shell particles, etc., and mixtures thereof. A suggested toughener is MBS core shell particles available from Rohm & Haas. The amount of toughening agent accounts for 1%-5% of the solid weight of the whole composition, and the recommended amount is 2%-4%.

(12) Other additives

The thermosetting resin composition of the present invention may further contain other additives such as defoamers, leveling agents, dyes, pigments and the like.

To sum up, the proportion range of each component of the thermosetting resin composition of the present invention is shown in Attached Table 1.

The ratio range of each component of the thermosetting resin composition of table 1

Note: ^＊ Because the amount of different flame retardants is different, it is added in an appropriate amount according to the use standard in the industry.

In the formulation, the mixture of MPGE and BMI is first dissolved in a solvent (the amount of the solvent is 50-70wt% of the weight of the entire reaction mixture), reacted at a certain temperature (60-130°C) for 10-60min under the action of an initiator, and then added Inhibitor, stirred while hot for 10-15min, cooled. The obtained prepolymer is then added with SMA, flame retardant, toughening agent and accelerator dissolved in a solvent such as butanone in advance, and after fully stirring, slowly add fillers and other additives, and then add an appropriate amount of solvent, the addition of solvent amount so that the solid content of the finally obtained resin composition is 45-70%, and the recommended amount of solvent is to adjust the solid content of the composition to be 50-65%. The thermosetting composition of the present invention is formed after thorough stirring.

Prepregs are manufactured in a continuous process using the thermosetting composition of the present invention. Usually glass fiber cloth is used as the base material. A roll of fiberglass cloth is passed continuously through a series of rollers into a gluing chute containing the thermosetting composition of the present invention. In the gluing tank, the glass fiber cloth is fully soaked by the resin, and then the excess resin is scraped off by the metering roller, and then it is baked in the gluing furnace for a certain period of time to evaporate the solvent and solidify the resin to a certain extent, then cool and wind up to form a prepreg .

Superimpose and align a certain number of sheets of electronic grade 7628 glass fiber cloth impregnated with the prepreg made of the above resin, and place a piece of 1oz electrolytic copper foil on the top and bottom. In a vacuum press, under a pressure of 40-900psi, the temperature is within 30min Raise from 80°C to 200°C, then hot press at 200°C for 120 minutes, and then cool to room temperature within 30 minutes to make a double-sided copper clad laminate with a certain thickness. Generally, 1.0mm thickness requires 5 7628 prepregs, 1.6mm requires 8 7628 prepregs, and 2.0mm requires 10 7628 prepregs.

The invention provides a thermosetting resin composition that forms a stable homogeneous solution in a low-boiling solvent. The copper-clad laminate manufactured with it, with reference to IPC-TM-650, is tested for glass transition temperature, thermal decomposition temperature, thermal delamination time, and solder resistance. Thermal properties (288°C), thermal expansion coefficient, water absorption rate, thermal conductivity, dielectric constant and dielectric loss factor, and flame resistance index testing, the test results show: high glass transition temperature (Tg), excellent dielectric properties, low expansion Coefficient, low water absorption, high thermal shock resistance and high thermal conductivity and other characteristics, suitable for electronic components and integrated circuit (IC) packaging substrate materials.

Detailed ways

The following examples are a detailed description of the present invention, but do not limit the scope of the present invention.

The preparation of embodiment 1MPGE/BMI prepolymer (hereinafter referred to as prepolymer I) (see attached table 2):

21.9 grams of MPGE (0.0886 equiv.), 31.7 grams of 4,4'-diaminodiphenylmethane type bismaleimide (0.0885 equiv.) and 104.0 grams of butanone (solvent) were added to a reflux condenser equipped with In the three-necked round-bottomed flask of tube, stirrer and thermometer, under N ₂ atmosphere, stirring is heated up to 80 ℃, divides and slowly adds 0.073 gram of azobisisobutylcyanide (free radical initiator) twice, reflux reaction 20min, then Add 0.048 gram of hydroquinone (inhibitor), and cool to room temperature. A solution of prepolymer I with a solids content of 34.0% was obtained.

The preparation of embodiment 2MPGE/BMI prepolymer (hereinafter referred to as prepolymer II) (see attached table 2):

Each reactant and method are with embodiment 1, but the consumption of each reactant becomes respectively: 43.8 gram MPGE (0.177equiv.), 31.8 gram 4,4'-diaminodiphenylmethane type bismaleimide (0.0885 equiv.), methyl ethyl ketone 147.1 grams, azobisisobutyronitrile 0.108 grams, hydroquinone 0.070 grams. A prepolymer II solution with a solids content of 34.0% was obtained.

The preparation of table 2MPGE/BMI prepolymer

The synthetic reaction equation of prepolymer I:

Copolymerization product in prepolymer I

The synthesis reaction equation of prepolymer II:

Copolymerization product in prepolymer II

Embodiment 3 to embodiment 14 and comparative example 1 to comparative example 3 thermosetting resin composition:

The formula of each embodiment is shown in attached table 3 and attached table 4.

The resin composition formula of table 3 embodiment 3-10

The resin composition prescription of table 4 embodiment 11-14 and comparative example 1-3

In prepolymer I and prepolymer II formula, the molar ratio (hereinafter referred to as MR) of BMI and MPGE is respectively 1: 1 and 1: 2, and in embodiment 3 to embodiment 10, filler ratio is 30% or 60% (mainly in order to investigate the impact of different fillers and their contents on the performance of the substrate); in the formulas of Example 11 and Example 12, the proportions of fillers are respectively 30% and 50%; in the formulas of Example 13 and Example 14, the proportions of fillers are respectively Be 30% and 50%, but the content of bromine in the system has improved, reaches 13.5% (not counting the weight of filler and BMI) (note: the content of bromine is 8.0% in the formula of embodiment 3 to embodiment 12); Comparative example 1 and 2 are without BMI, and the filler ratios are 30% and 50% respectively; the MR in the formula of Comparative Example 3 is 1:1, and no filler is added.

Embodiment 3 is taken as an example for description. In the container that is equipped with high-speed stirring device, put into 70.1 gram prepolymer I, add 205.0 gram butanone and 29.8 gram brominated bisphenol A epoxy resins (60% butanone solution, epoxy equivalent 400), stir , sequentially add 103.6 grams of SMA3000 (add in small batches), 3.0 grams of MBS core-shell particles, 0.006 grams of 2-ethyl-4-methyl-imidazole (add after diluting with MEK), and then slowly add 88.5 grams of nitriding aluminum. Stir for more than 1 hour and let stand.

For simplicity, the prepreg was prepared by manual impregnation. Use 7628 glass fiber cloth to dip into the above resin solution for gluing, and bake at 155°C for 3-5min to make a semi-cured adhesive sheet.

Superimpose and align a certain number of 7628 (or 106) glass fiber cloth impregnated with the prepreg made of the above resin, with a piece of 1oz electrolytic copper foil on the top and bottom, in a vacuum press, under the pressure of 40-900psi, the temperature is 30min The internal temperature is raised from 80°C to 200°C, then hot-pressed at 200°C for 120 minutes, and then cooled to room temperature within 30 minutes to make a double-sided copper clad laminate with a certain thickness. Generally, 1.0mm thickness requires 5 7628 prepregs (or 20 106 prepregs), and 1.6mm requires 8 7628 prepregs.

The substrate pressed by 7628 glass cloth is used for characteristic testing (such as glass transition temperature, peel strength, CTE, heat resistance, water absorption, flame retardancy, dielectric property, etc.), and the substrate pressed by 106 glass cloth is used for heat conduction rate test.

According to IPC-TM-650, the copper clad laminate is tested. The test results are shown in Attached Tables 5 and 6, which are summarized below.

Table 5 Embodiment 3-10 Substrate characteristics

Table 6 Embodiment 11-14 and comparative example 1-3 substrate characteristic

[0108] Since the following detection methods are commonly used methods in the art, the specific detection steps will not be repeated herein.

1) Glass transition temperature (Tg)

The glass transition temperature refers to the temperature (°C) at which the plate changes from a glass state to a high elastic state (rubber state) when heated.

Detection method: differential scanning calorimetry (DSC) and thermomechanical analysis (TMA).

The results show that the plate has a high glass transition temperature (Tg), reaching above 200 °C (DSC).

2) Thermal decomposition temperature (Td)

Thermal decomposition temperature (Td) refers to the temperature (°C) at which the plate produces a thermal decomposition reaction under the action of heat.

Detection method: thermogravimetric analysis (TGA). The conditions are: the heating rate is 10° C./min, and the thermal weight loss is 5%.

The results show that the plate has a high thermal decomposition temperature, and the Td reaches above 355℃.

3) Thermal stratification time (T-300)

T-300 thermal stratification time refers to the duration of time before the stratification phenomenon occurs due to the effect of heat at the set temperature of 300 °C.

Detection method: Thermomechanical analysis method (TMA).

The result shows: plate has higher thermal delamination temperature and thermal delamination time, and the delamination time of T-300 is except embodiment 3 and 4 lower (but still have 15.6min and 11.5min respectively), all the other all reach 40min above.

4) Solder heat resistance

Solder heat resistance refers to the duration of time when the plate is immersed in molten solder at 288°C without delamination and blistering.

Detection method: cut the etched substrate into a size of 5.0mm×5.0mm, polish the edges of the board with 600 mesh and 1200 mesh sandpaper in turn, cook in a pressure cooker for a certain period of time, put it in a tin melting furnace at 288°C for 10 minutes, and observe whether there is delamination And so on.

The results show that the plates all have excellent solder heat resistance, and the duration is above 10min at 288°C.

5) Coefficient of thermal expansion (CTE)

The coefficient of thermal expansion (CTE) refers to the dimensional change between the unit temperature rise of the plate under the condition of heating.

The CTE of the plate has a great relationship with the temperature condition, especially the CTE in the thickness direction, there is a big difference when the temperature exceeds Tg and when it is below Tg.

Packaging requires that the thermal expansion coefficient of the substrate material should have a thermal expansion coefficient that matches that of Si to ensure compatibility with Si chip packaging.

Detection method: thermomechanical analysis (TMA).

The results show that the plate has excellent dimensional stability and low CTE under heat action, the X/Y axis CTE<12ppm/℃, and the Z axis CTE<13ppm/℃.

6) Water absorption

Water absorption refers to the ratio of the mass of water that the plate can absorb under certain conditions, such as a pressure cooker for a certain period of time, to the dry mass of the sample.

Detection method: cut the etched substrate into a size of 5.0mm×5.0mm, polish the edges with 600-mesh and 1200-mesh sandpaper in turn, bake at 105°C for 2 hours, and cook in a pressure cooker for a certain period of time.

The results show that after 5 hours of PCT, the water absorption of the boards is low, all below 0.16%.

7) Thermal conductivity

The definition of thermal conductivity is the ability of the plate to conduct heat directly, or thermal conductivity. It is characterized as the heat directly conducted by a plate of unit cross-section and length under unit temperature difference and unit time. High thermal conductivity to prevent overheating of multilayer substrates.

Detection method: laser scattering method, according to ASTM E-1461 standard.

The results show that the plate has a high thermal conductivity, which can be guaranteed to be 1.0W/m.k on the X/Y axis and 0.55W/m.k on the Z axis, indicating that it has good thermal conductivity.

8) Dielectric constant and dielectric loss factor

The dielectric properties of electronic packaging materials are an important factor affecting the operation speed of integrated circuits. If the dielectric constant is too high, the signal transmission delay of the integrated circuit will increase, and the high dielectric loss factor will cause serious distortion of the signal during transmission. . Therefore, the dielectric constant and dielectric loss factor are two important indicators to characterize the high-frequency characteristics of materials.

Detection method: cut the etched substrate into a size of 5.0mm×5.0mm, polish the edges of the board with 600 mesh and 1200 mesh sandpaper in turn, bake at 105°C for 2 hours, and then test it on a megger.

The results show that the dielectric constant and dielectric loss factor of the plate are low, the dielectric constant of the plate is 3.7-3.9 at 1GHz, and the dielectric loss factor is 0.006-0.007.

9) Flame resistance

The copper foil on the surface is removed by etching, and the sample preparation and testing are carried out according to the flammability test of UL94 laminated boards.

The results show that the flame resistance of the panels can reach UL94V-0 level.

As can be seen from the comparison of Examples 3-14 and Comparative Examples 1-2, the characteristics of the copper-clad laminate made of the thermosetting resin composition made of the prepolymer provided by the present invention are compared with the copper-clad laminate made by pure MPGE. Higher Tg and heat resistance, lower CTE and water absorption, and better dielectric properties and thermal conductivity. In addition, there is no filler added to the resin composition in Comparative Example 3, and its CTE and water absorption are much higher than those of the resin composition with filler added, and its thermal conductivity is relatively poor, indicating that the copper clad laminate made of the thermosetting resin composition provided by the present invention has Excellent substrate properties.

The thermosetting resin composition that the prepolymer provided by the invention is made:

1. Compared with the existing epoxy resin, the water absorption rate is low, which improves the shortcoming of epoxy resin sensitive to water under high temperature and high humidity conditions;

2. Compared with the existing cyanate ester resin, it is cheaper and has a lower water absorption rate, which improves its shortcoming of high brittleness after curing;

3. Compared with the existing bismaleimide resin, it can be dissolved in general organic solvents, easy to process, and has high thermal shock resistance;

4. Compared with the existing BT resin, it is cheap, easy to process, and can form a stable solution in various low boiling point solvents, which improves its shortcoming of high brittleness after curing.

In summary, the copper clad laminate material made of a thermosetting resin composition made of a prepolymer provided by the present invention has a high glass transition temperature (Tg), excellent dielectric properties, low expansion coefficient, low water absorption, The characteristics of high thermal shock resistance and excellent thermal conductivity meet the requirements of various characteristics of IC packaging substrates. Because of its special low-cost research ideas, it is conducive to promoting the wide application of IC packaging substrate materials.

Claims (14)

1. a prepolymer is characterized in that: with 4-(N-maleimide phenyl) glycidyl ether epoxy resin and 4,4'-diaminodiphenylmethane type bismaleimide As a reactant, the reaction is initiated by a free radical initiator in a solvent, and after the reaction, a polymerization inhibitor, 4,4'-diaminodiphenylmethane type bismaleimide and 4-(N-maleimide The molar ratio of iminophenyl) glycidyl ether epoxy resin is 0.05 to 0.5; the amount of initiator is 0.01%-0.15% of the total molar amount of the reactant monomer; the amount of solvent is 50%-70% of the total weight of the reactant ; The amount of the polymerization inhibitor is half to one time the molar amount of the initiator used. 2. A kind of prepolymer as claimed in claim 1, is characterized in that: solvent is one or more in acetone, toluene, cyclohexanone, methylene chloride, butanone or methyl isobutyl ketone. 3. A prepolymer as claimed in claim 1, characterized in that: the initiator is an azo initiator, the reaction temperature is controlled at 60-90°C, and the reaction time is controlled at 10-60min. 4. A prepolymer as claimed in claim 1, characterized in that: the initiator is a peroxide initiator, the reaction temperature is controlled at 100-130°C, and the reaction time is 10-60min. 5. A kind of prepolymer as claimed in claim 1, it is characterized in that: the polymerization inhibitor is one of quinones, aromatic nitro compounds, variable-valence metal salt electrophilic substances, phenols or amines species or several. 6. A kind of prepolymer as claimed in claim 1, is characterized in that: 4,4'-diaminodiphenylmethane type bismaleimide and 4-(N-maleimide phenyl) The molar ratio of the glycidyl ether epoxy resin is 0.25 to 0.475. 7. A kind of prepolymer as claimed in claim 1, it is characterized in that: the amount of initiator is 0.05%-0.10% of the total molar amount of reactant monomers. 8. A kind of prepolymer as claimed in claim 1, is characterized in that: solvent consumption is 60%-70% of the total weight of reactant. 9. The thermosetting resin composition that utilizes a kind of prepolymer described in claim 1 to make, is characterized in that: comprise following composition: (1) a kind of prepolymer described in claim 1, accounts for composition solid 1.90-34.5% of the weight of the composition; (2) at least one styrene-maleic anhydride oligomer, accounting for 17.5%-47.0% of the composition solid weight; (3) at least one filler, accounting for the composition solid 20%-60% by weight; (4) at least one solvent, the amount of solvent added accounts for 20%-50% by weight of the composition; (5) at least one flame retardant that can be used in the copper clad laminate industry. 10. The thermosetting resin composition according to claim 9, wherein the molecular weight of the styrene-maleic anhydride oligomer is in the range of 1400-50000. 11. The thermosetting resin composition according to claim 9, characterized in that the styrene-maleic anhydride oligomer accounts for 22.5%-38.0% of the weight of the solid content of the composition. 12. The thermosetting resin composition as claimed in claim 9, wherein the filler is crystalline silica, fused silica, spherical silica, alumina, mica, talcum powder, boron nitride, nitrogen One or more of aluminum oxide, silicon carbide, diamond, calcined clay, aluminum oxide, aluminum nitride fiber or glass fiber. 13. The thermosetting resin composition according to claim 9, wherein the solvent comprises one or a mixture of acetone, butanone, methyl isobutyl ketone, toluene or methylene chloride. 14. The thermosetting resin composition according to claim 9, wherein the flame retardant is brominated bisphenol A epoxy resin, accounting for 5.00%-32.5% of the weight of the solid content of the composition.