TGV通孔双面电镀铜填充模式调控及工艺可靠性试验研究

TGV through-hole double-sided electroplated copper filling moderegulation and process reliability test study

通过双面电镀铜实现TGV(Through Glass Via)通孔部分实心填充,兼具TGV通孔密度高、TGV厚度尺寸范围大、热力学可靠性高、圆片级/板级工艺流程简单等优点,是“芯粒”2.5D/3D集成、光电共封装(Co-Packaged-Optics,CPO)等先进封装用TGV转接板潜在优选金属化路线.本文将介绍基于国产电镀药水体系和课题组设计电镀槽体通过电镀参数设计实现TGV通孔双面电镀铜填充模式的调控,实现了X型以及“桥型”直通型TGV孔金属化;据JEDEC标准试验研究了TGV通孔glass–Ti–Cu金属化体系在高温加速老化测试(Highly Accelerated Stress Test,HAST)、温度循环测试(Temperature Cycle Test,TCT)、高温存储(High Temperature Storage,HTS)等可靠性表现,验证了TGV部分实心填充金属化工艺优点,试验发现了TGV铜互连氦气漏率、直流电阻对HAST试验最为敏感,Ti–Cu界面微缺陷、贯穿性裂纹产生是HAST试验中TGV铜互连主要失效模式,揭示了TGV铜互连Cu–Ti–glass材料体系中Ti趋于向glass衬底扩散、Cu趋于向Ti层扩散,由此在Ti–Cu界面产生缺陷、形成微裂纹,为金属化材料体系选择与阻挡层厚度设计提供指导;展示了用于体硅RF MEMS器件圆片级封装TGV盖帽圆片、2.5D射频集成大面积TGV转接板样品、TGV转接板堆叠集成毫米波天线等,演示其圆片级工艺应用可行性,为后续集成应用做技术储备.

The solid filling of through-glass via(TGV)through-hole part through double-sided electroplating copper has the advantages of high TGV through-hole density,large TGV thickness and size range,high thermodynamic reliability,wafer-level/board-level process,and simple process flow,and is a potential preferred metallization route for TGV interposer boards in advanced packaging applications such as“core”2.5D/3D integration and photoelectric copackaging(co-packaged-optics,CPO).This paper introduced the regulation of the copper layer on the copper layer in the process of double-sided electroplating copper filling TGV through-hole design based on the domestic electroplating chemical system and the design of the research group,and realized the copper-plating copper-metallization method of Xtype and“bridge-type”straight-through hole TGV holes.According to the JEDEC standard test,the reliability performance of the TGV through-hole glass–Ti–Cu metallization system in the highly accelerated stress test(HAST),temperature cycle test(TCT),high-temperature storage(HTS)and other aspects was studied.The advantages of TGV partial solid filling metallization process were verified,and it was found that the vacuum leakage rate and DC resistance of TGV copper interconnection were the most sensitive to the HAST test,while the microdefects and penetrating cracks of the Ti–Cu interface were the main failure modes of TGV copper interconnection in the HAST test,revealing that Ti tends to diffuse to the glass substrate and Cu tends to diffuse to the Ti layer in the TGV copper interconnect Cu–Ti–glass material system,resulting in defects at the Ti–Cu interface.The crack is the main mechanism of microcrack formation,which provides guidance and suggestions for the selection and design of metallized material system.The wafer-level packaging TGV cap disc for bulk-silicon RF MEMS devices,RF-integrated large-area TGV adapter board samples,TGV adapter board stacking-integrated millimeter wave antennas were displayed,demonstrating the feasibility of waferlevel process application and making technical reserves for subsequent integration applications.