Preparation And Modification Of Low Dielectric Constant Self-curing Epoxy Resin

With the development of ultra-large-scale integrated circuit technology,nanoscale has become the measurement scale of the dominant component size.The requirements of reducing signal interconnection delay,reducing noise and power consumption,etc.,have posed higher challenges to the performance of the dielectric layer of epoxy resin.The preparation of low-dielectric epoxy resin material has become an important demand for the development of circuit technology.Compared with the traditional epoxy resin,the self-curing epoxy resin can be formed after being heated,which avoids the cumbersome process of weighing and mixing epoxy resin with curing agent,and also avoids the material defects caused by improper addition of curing agent or uneven mixing.This paper explored the preparation method of low dielectric self-curing epoxy resin,and the following scientific research achievements were obtained:The molecular structure and preparation route of self-curing epoxy resin(SC-EP)with symmetrical structure were designed.The effects of reaction temperature,catalyst content and solvent content on the preparation process were investigated,and an efficient preparation method of low dielectric glycidyl ester self-curing epoxy resin was obtained:under the condition of 90℃,with etramethylammonium hydroxide pentahydrate as catalyst,and mole ratio of 2,5-dihydroxyterephthalic acid,epichlorohydrin,etramethylammonium hydroxide pentahydrate is 1:17.5:0.12.The preparation process is short in time,simple in operation,and the amount of solvent and waste liquid is greatly reduced.The self-curing epoxy resin has a long stable storage period at room temperature(more than14 months).The dielectric constant of SC-EP material prepared by this process is only 3.3(1 MHz),which is 21%lower than that of ordinary epoxy resin.The significant influence region of benzyl glycidyl ether on the dielectric properties of SC-EP materials is located in the high content region of 25%～35%,and the dielectric constant of composite materials can be reduced to 2.1(1 MHz).It is necessary to add a large amount of benzyl glycidyl ether to reduce the dielectric constant.The significant influence of 1,4-butanediol diglycidyl ether on the dielectric properties of SC-EP materials lies in the low content area of less than 10%,and the dielectric constant of composite materials can be reduced to 2.3(1 MHz),which is an ideal dielectric modifier.The addition of glycidyl ether polyhedral oligomeric silsesquioxanes(G-POSS)increased the curing temperature of SC-EP.When the addition amount of G-POSS is about 1%，the dielectric constant of the composite material can be reduced to about 3.18(1 MHz).A series of microbubble epoxy resin materials with different diameters were obtained by controlling the desiccation time and temperature to inhibit solvent escape from the material.The smaller the diameter of the microbubble,the lower the dielectric constant of the material,and the lowest dielectric constant of the microbubble SC-EP material can be reduced to about 2.2(1 MHz),about 33%lower than that of pure SC-EP material.The characteristic temperature of SC-EP curing process was analyzed.The initial curing temperature is 115.78℃,the peak temperature is 170.80℃,the curing end temperature is 213.62℃,so the optimal curing temperature is about 170℃.Using the model fitting method to calculate the activation energy for SC-EP curing processΔE=70.58 kJ·mol-1·K-1,A=3.68 ×105 s-1.The kinetic parameters obtained by Kissinger method,Starink method and FWO method are consistent.The addition of G-POSS and diluent has little effect on the curing activation energy.Finally,the synthesis of the low dielectric epoxy resin material was amplified in 5L volume at the laboratory scale.The carboxyl group transformation curve in the reaction kettle is basically consistent with the results of the 0.5 L volume test,which proves that the synthesis route has the conditions of amplification.In order to facilitate the amplification of the post-treatment process,the coupling processes of desorption and self-curing were analyzed.SC-EP has low viscosity and slow curing reaction in the temperature range of 80℃-100℃,which is conducive to the removal of small molecules such as solvents.On the basis of the 5L amplification experiment,the material balance of the 300L pilot experiment were also calculated,and the process flowchart was designed according to the material characteristics and operation requirements.