ウエハ温度制御による高精度深孔エッチングの検討（第1報）: 装置の試作とプロセス中温度制御の効果検証

摘要

Novel wafer-cooling system based on direct expansion phenomenon of coolant has been developed in order to improve etching performance for high-aspect-ratio contact (HARC) process. This system provides effective cooling capability and rapid wafer temperature control. In this study, prototyping of basic equipment was performed and etching performance in HARC process was evaluated. As a result, temperature control speed of 0.6 ℃/s was achieved over a 300mm- φ wafer. Furthermore, etching rate and mask selectivity at 100nm- φ aspect-ratio of 20 HARC sample could be increased by around 6% and 14% respectively without any etching profile deformation by 2-step wafer temperature control from 61℃ to 50℃ during etching in C_4F_6/Ar/O_2 plasma. It is concluded from the results that this system can improve etching performance for HARC.%半導体デバイスの微細化に伴い，絶縁膜エッチングの高 精度化への要求が厳しくなっている．特にDRAM (Dynamic Random Access Memory) のキャパシタ形成に必要なHARC (High Aspect Ratio Contact) エッチングでは，更なるホール径の微細化，および高アスペクト化が求められている．半導体のロードマップであるITRSによれば，2013年にはホール径50nmでアスペクト比50以上のエッチング技術が必要とされる．