Preparation method of MQ branched-chain modified silicon resin polymer for large-scale integrated circuit package

The invention discloses a preparation method of an MQ branched-chain modified silicon resin polymer for large-scale integrated circuit package. Alpha, omega-dyhydroxyl polydimethylsiloxane or alpha, omega-hydroxyl poly(dimethyl-methyl vinyl) silicon dioxide is taken as a main raw material, methyl vinyl MQ silicon resin with the value of M/Q value being 0.6-0.9 or methyl MQ silicon resin is taken as an auxiliary raw material, the mixture is stirred to have a reaction for 45 minutes at the rotation speed of 70 revolutions per minute, the temperature is raised to 50-130 DEG C, and the temperature rising rate is 2 DEG C per minute; sodium trimethylsilanol or potassium trimethylsilanol accounting for 0.01%-0.1% of the main raw material by mass is added to serve as a catalyst, the mixture is stirred for 1-4 hours at the constant temperature, and a target product is obtained. The tensile strength, the impact strength and the adhesive property of the polymer prepared with the method are excellent, the resistance is higher than 1,013 omega, the heat conductivity is lower than 1.40 W/mK, the silicon resin polymer can resist radiation not lower than 109 rad, and the elasticity is good.