Studies On Aluminum Nitride Ceramic Metallization

In this paper,metallized thin films of Ti of different thickness on AlN substrate were deposited by magnetron sputtering,and then a layer of Cu metal is deposited on the surface of Ti metal by electrochemical deposition,so that the three layers of material are compact,and heat treatment in an Ar gas atmosphere at a temperature of500-700?to realize the Cu metallization of the Al N ceramic surface.The deposition mechanism of Ti on Al N ceramics and the influencing factors on the bonding properties of AlN/Ti/Cu and Cu/Ti were investigated.The main results are followed:?1?When the holding time is the same,with the increase of holding temperature,the connection between Cu and Ti becomes more and more strong,the interlayer thickness increases obviously,it's from almost invisible to 3.75?m when the holding temperature from 500?to 700?for 1h,and the species of intermetallic phase also increases correspondingly,from 1 phase?CuTi?to 5 phases?Cu₄Ti₃?Cu₃Ti₂?CuTi?CuTi₂?CuTi₃?,and CuTi is the phase which appear earliest.The tensile strength of the Cu/Ti connector increased with the increase of the holding temperature,the hardness of the intermediate layer was enhanced from one aspect,but the brittleness of the Cu/Ti connector also increased.When the temperature is lower than 500?,Cu and Ti will be difficult to combine.?2?When the holding temperature is the same,with the increase of the holding time,the connection between Cu and Ti becomes more and more strong,the interlayer thickness increases obviously,when the holding temperature is 600?and 650?,holding time is 5h and 6h,the thickness increased from 2.25?m and 3?m for 1h to3.6?m and 4.5?m,respectively,the species of intermetallic phase also increases correspondingly,the new phases Cu₃Ti and Cu₄Ti were detected,and CuTi is the phase which appear earliest,but the new phases is the original phase content to the minimum concentration of XRD detection.The tensile strength of the Cu/Ti connector increased with the increase of the holding time,the hardness of the intermediate layer was enhanced from one aspect,but the brittleness of the Cu/Ti connector also increased.?3?At a constant working power?145W?,The main growth pattern of the Ti film on the surface of AlN ceramic is island grown,the longer time of the electrodeposition,the thicker and uniformly continuous of the Ti films?more than30min?.However,if the thickness of the Ti layer is too thick,the intermediate layer between the AlN ceramic and the metal is excessively thick,which affects the thermal conductivity of the bonding joint.?4?During the heat treatment of the AlN/Ti,the AlN ceramic will reacts with Ti.This reaction is initiated from the interface of the ceramic and the metal.In the case of the same holding time,the higher holding temperature,the thicker the region of the reaction product,and then the reaction product will get to the surface of Ti film.When the thickness of the Ti deposition layer is about 1.7?m,the sample is held at 700?for 1h,the reaction product of AlN ceramic and Ti will cover the whole Ti metal layer..The reaction product is TiN and TiO₂,TiN is from the reaction of AlN and Ti,Whereas TiO₂ is produced by the reaction of Ti and the sintering aids?from AlN ceramic?.?5?In the Al N/Ti/Cu bonding joint,Ti react with Cu and AlN,so that Ti can connect ceramic and metal,Cu/Ti intermetallic compound is produced by reaction of Cu and Ti,and TiN is produced by reaction with AlN ceramics.?6?During the heat treatment of the Al N/Ti/Cu,oxides produce at the Cu/Ti interface or before the heat treatment,Cu is separated from the Ti,and after heat treatment,bubbling occurs on the surface of the AlN/Ti/Cu,By eliminating the oxide can reduce the occurrence of bubbling.