Synthesis And Properties Of A Novel Hyperbranched Polycarbosilane-siloxane Low Dielectric Resin

The development of semiconductor industry and circuit board industry has put forward higher requirements for high frequency,high speed,miniaturization and high density.But the problems such as the increase of signal delay,crosstalk and power consumption are becoming more and more serious.Using the materials with low dielectric constant and low loss as the dielectric material between layers and wires is one of the effective ways to solve this problem.Therefore,the research and development of high-performance,low-dielectric and low loss materials,a key basic material for semiconductor industry and circuit board industry development,as well as the development of electronic information industry has important practical significance.In this paper,starting from the molecular structure design,a series of new hyperbranched Polysiloxane/carbosilane hybrid resins with high-performance and low-dielectric were synthesized,shows the good performance of low dielectric and low loss,high thermal stability,good mechanical properties,excellent processing and film performance.The main research work carried out and the main results achieved are as follows:1.A novel hyperbranched silicon-carbon benzocyclobutene oligomer（HBCSBCBOs）was successfully prepared from chloromethyl trichlorosilane through Grignard reaction and then reaction with 4-bromobenzocyclobutene by one-pot method.The structure of HBCSBCBOs was characterized and the curing cross-linking conditions were studied.The results shown that the resin after curing has low dielectric constant（10 MHz,k=2.66,dielectric loss 0.05）,high thermal stability(T_5%=478.3℃),and excellent mechanical properties（modulus about7.1 GPa）.The results showed that the resin had good film forming property and film flatness.Based on the special molecular structure and potential low dielectric construction unit of cage type sesimiciloxane,the physical mixing method was used to add octavinylsesimiciloxane（OVPOSS）into HBCSBCBOs resin for blending,in order to further improve the dielectric properties.The effects of different OVPOSS contents（5%,10%,20%,30%）on the dielectric properties and mechanical properties of hybrid resin materials were studied.The results showed that the resins had good processing properties.The dielectric properties decreased with the increase of OVPOSS content（k about 2.59,dielectric loss about 1.10×10-²）,and the mechanical properties increased with the increase of OVPOSS content（modulus about 8.5 GPa）.The cured resin also showed good film forming properties.The experimental results show that the introduction of OVPOSS with nanometer aperture structure can reduce the dielectric constant and dielectric loss of the hybrid resin to some extent.In order to explore the possibility of different blends to improve the dielectric properties of HBCSBCBOs resin,DVSBCB,which with good dielectric properties and the special structure of its own double BCB functional group,was mixed with HBCSBCBOs resin in different proportions by physical blending.The results showed that the dielectric properties and mechanical properties of the resin were improved first and then decreased with the decrease of DVSBCB content.The optimized mass ratio was 1:1,k was 2.51,dielectric loss was 1.36×10-³ and modulus was 5.3 GPa.The introduction of DVSBCB also significantly improved the dielectric properties.2.A novel hybrid oligomer（HBSO/CSBCBOs）with hyperbranched structure and recrosslinking was prepared using chloromethyl-trimethoxysilane as raw material through Grignard reaction,Grignard reaction of 4-bromobenzocyclobutene and hydrolysis condensation reaction successively.The curing and crosslinking conditions of the resin were studied.The results show that the cured resin has good dielectric properties（10 MHz,k about 2.60,dielectric loss about 5.21×10-³）,excellent thermal stability(T_5%about 481℃),good mechanical properties（modulus about 6.9 GPa）and film forming properties.In order to further improve the dielectric properties,The dielectric properties and mechanical properties of the blend resin were studied.The results showed that the resin had good processing properties,the dielectric properties decreased with the increase of OVPOSS content（k about 2.54,dielectric loss about 1.13×10-³）,and the mechanical properties increased with the increase of OVPOSS content（modulus about 8.6 GPa）.The cured resin also showed good film forming properties.The experimental results show that the introduction of OVPOSS with nanometer aperture structure can obviously reduce the dielectric constant and dielectric loss of the hybrid resin.3.A new type of silocyclobutane monomer and its hyperbranched polymers were designed and synthesized.Several novel cyclosiloxane monomers（PSCB-CPSO,TPDSCB-CTSO and HMTSCB-CHSO）based on silocyclobutane functional groups were synthesized from 1,1-dichlorosiloxane（DCSCB）with yields of 40～75%by one-step hydrolysis or alcoholysisreaction.These cyclosiloxane monomers can be UV cured under the catalysis of platinum acetyl acetone or thermal cured under high temperature due to the presence of silocyclobutane groups.The polyoxysilane resin obtained after ring-opening curing exhibits excellent high temperature resistance(T_5%about 540℃),low dielectric constant（10 MHz,k about 2.36～2.76）,and high modulus of elasticity（2.46～2.69 GPa）.This new class of polymers also has a low dielectric constant compared to most current polymer substrates（without introducing fluorine and porous structures）.In addition,this new resin also has the potential of photopatterned low dielectric.In this paper,a series of Polysiloxane/carbosilane hybrid low dielectric resin materials were designed and synthesized,and the co-hybrid and performance research was carried out.A number of resin systems studied showed excellent comprehensive performance,which is expected to become a potential key basic material of high frequency,high speed and small density in the semiconductor industry and circuit board industry.