摘要
研究基于高功率碳化硅器件的低温封装应用需求,开发了碳化硅陶瓷与散热铜板的低温连接工艺.首先通过磁控溅射技术对碳化硅(SiC)进行表面金属化处理,再采用Sn基钎料对碳化硅和无氧铜进行低温真空钎焊,从而实现了SiC-Cu的钎焊连接,分析并揭示了碳化硅表面的金属化层厚度,以及Sn基钎料成分对SiC-Cu钎焊接头组织和力学性能的影响.结果表明,SiC-Cu钎焊接头的结合强度与母材SiC一侧界面处冶金反应的程度直接相关,受Sn基钎料成分及SiC表面金属化Cu层厚度的影响,当采用SnCu钎料时,钎焊接头中靠近SiC界面处冶金反应较为充分,生成的金属间化合物主要为Cu6Sn5,且随着Cu层厚度的增加反应产物逐渐增多,接头结合强度不断提高,当Cu层厚度达到 2000 nm时,SiC-Cu钎焊接头的结合强度可达峰值14 MPa左右.
Abstract
In requirement of the low-temperature packaging applications for high-power SiC devices,a low-temperature bonding process for SiC ceramics and heat-dissipating Cu plate is put forward in this research.The SiC-Cu joint was successfully achieved by surface metallization of silicon carbide through magnetron sputtering technology and low-temperature vacuum soldering with Sn-based fillers.The influence of the thickness of metallized Cu layer on SiC and the composition of the Sn-based fillers on microstructure and mechanical properties of the SiC-Cu joint was analyzed and realized.It is proposed that the shear strength of SiC-Cu joints depends on the degree of metallurgical reaction close to the boundary between SiC and Sn-based fillers,which is influenced by the composition of Sn-based filler and the thickness of the metallized Cu layer.The intermetallic compound(IMC)near SiC in the SiC-Cu joint is mainly Cu6Sn5 and its quantity increases with the increasing thickness of the Cu film,leading to the improvement of shear strength of the joint.As a result,the SiC-Cu joint soldered by SnCu filler has a peak shear strength of about 14 MPa when the thickness of Cu film on surface of SiC is about 2000 nm.
NETL
NSTL
万方数据