Perhydropolysilazane Derived Sion Interfacial Layer For Electronic Encapsulation

Epoxy molding compound(EMC)is the most used encapsulation composites in semiconductor field.However,due to their great differences in chemical and physical properties,the delamination of Cu/EMC caused by interfacial oxidation or corrosion is considered to be a key factor to affect the reliability of Cu/EMC composites.In this work,the coatings with SiON structure derived from perhydropolysilazane(PHPS)were prepared.The bonding strength,corrosion and thermal conductance of the metal/SiON/EMC were well studied.This work thus presented a promising strategy to construct thin SiON interfacial layers to improve the bonding strength and increase the durability for metal/EMC composites.The main work and results are summarized as follows:1.The interfacial layers were prepared by PHPS with different concentration.The surface morphology and constituent of the interfacial layer were investigated by FTIR,SEM and EDS,resipeitively.The results suggested that the interfacial layer derived by PHPS was dense,crack-free,and the obtained SiON film contained reactive groups,such as Si-OH,Si-NH-Si,Si-H and N-H bonds.2.The copper-based substrate(Cu)is the main choice as skeleton of packages in micro electronics industry.By adjusting the concentration of PHPS solution,coating method,and heating curing temperature,the interfacial layer with the most significant bonding strength to Cu/EMC was explored by electromechanical universal testing machine.And the cross-sectional morphologies,thickness and fracture behavior were also investigated by SEM and EDS in detail.The results revealed that the bonding strength of Cu/SiON(21 nm)/EMC(heat)attained the highest value of 6.55(±0.08)MPa,representing an increase of 57%,and the fracture occurred inside the EMC.The bonding mechanisms among SiON interfacial layer and Cu or EMC had been analyzed by XPS,FTIR and white-light interfering profilometer.The results suggested that the covalent bonds(Cu-O-Si)were formed in the interface of Cu/SiON,and the great adhesion strength between EMC and Cu/SiON was attributed to the synergistic effect of hydrogen bonds and mechanical interlocking.3.PHPS was converted into SiON layers via vacuum ultraviolet irradiation cured.The influence of PHPS solution concentration on the bonding strength of Cu/EMC and the fracture behavior as well as the interface bonding mechanism was also studied by electromechanical universal testing machine,SEM,EDS and XPS.The results showed that the bonding strength of Cu/SiON(31 nm)/EMC(VUV)can be attained at the highest value,which was 88%,ang much higher than that of Cu/EMC.Almost all fractures occurred in interior of the EMC,and had more residual EMC than that of Cu/SiON(21 nm)/EMC(heat).The peak area of Cu-O-Si covalent bonds generated between Cu and PHPS was also greater than that of Cu/SiON(21 nm)/EMC(heat).4.The stainless steel,Mg,Ni and Ag were selected as the representative metals.And the SiON interfacial layer was prepared though vacuum ultraviolet irradiation curing.The bonding strength,fracture behavior and the interface bonding mechanism were studied by electromechanical universal testing machine,SEM,EDS and XPS.Because of the metal-O-Si covalent bonds the bonding strength between stainless steel,Mg,Ni and EMC was significantly increased by 176%,284%and 605%,respectively.In the absence of hydrogen bonds on the surface of silver,the more thickness of the SiON interfacial layer,the lower bonding strength of the Ag/SiON/EMC(VUV).5.The influence of SiON interfacial layer on the corrosion resistance and the thermal conductivity of metal/EMC was investigated by scanning acoustic microscopy,electromechanical universal testing machine,Tci and infrared thermographic imaging system.The SiON interfacial layer could guarantee excellent barrier to moisture and ionic impurities.Meanwhile,the thin SiON interfacial layer had a negligible effect on the thermal conductivity of the metal/EMC.