Research On The Key Technologies Of Direct Electroplated Copper Ceramic Substrate(DPC)

High power,high frequency and integrated electronic devices generally work in high temperature and other harsh environments,which puts forward higher requirements for chip packaging substrate.The packaging substrate needs to have high temperature resistance,high strength,high thermal conductivity,corrosion resistance,coefficient of thermal expansion(CTE)matching with chip,etc.The direct plated copper ceramic substrate(DPC)can meet the above requirements,and its preparation uses plating process to fill through-hole and growth surface pattern,realizing high-density interconnection of ceramic substrate.In this paper,the key technologies of DPC ceramic substrate electroplating were studied.The main research contents are as follows:1)The technology of void-free filling of through ceramic holes by direct current(DC)plating was studied.Magnetron sputtering was used to realize the metallization of ceramic through hole.By studying the metallization effect of magnetron sputtering through holes with different thickness diameter ratio,the appropriate range of thickness diameter ratio was determined.Based on the theory of "butterfly hole formation",an additive formulation of DC plating through hole(150g/L Cu SO4,60g/L H2SO4,40mg/L HCl,6mg/L SH110,0.7mg/L JGB and 150mg/L PEG)was developed.The optimal current density of the process is 1.6ASD.Under the optimal process conditions,high-speed and void-free filling of through ceramic holes can be achieved.2)The surface pattern plating technology of DPC ceramic substrate was studied.The surface pattern of DPC ceramic substrate was prepared by pulse reverse electroplating.Through process optimization,a pattern with great performance was obtained.Influence of electroplating process on pattern quality was deeply analyzed,including accuracy,thickness uniformity,roughness,microstructure,bonding force between plating layer and ceramic,substrate warpage and corrosion resistance.Through surface grinding,pattern of roughness and thickness uniformity was optimized.