Improvement in Profile and Critical Dimension by Carbon Hard Mask in Metal Etching

• Main Authors: Huang-Wei Chen, 陳煌威
• Other Authors: Zing-Way Pei
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/20066642474463259850

碩士 === 國立中興大學 === 光電工程研究所 === 104 === As technology improving, the integrated circuit has scaled into nano-level. However, insufficient photo resist caused by smaller lithography pattern, thinner photo resist and thicker oxide layer in etching process has made plasma etching tricky, such as vague lithography pattern. Under the setting, the study used hard mask on the stack of films to improve the etching process. In the process of metal etching, the study used carbon-based mask to etch the under-lying oxide layer, and replaced photo resist mask. And then the oxide layer served as mask to etch the metal layer. Comparing to photo resist mask, oxide layer accessed by carbon-based mask can effectively reduce distortion and obtain more vertical oxide etched profiles. In etched profile and dimensions, the carbon hard mask also improved etching process on metal layer with wider etched profile, wider critical dimensions about 5~10 nm and got better transferred pattern. The resistance of metal layer derived from carbon-based hard mask was 0.30~0.32Ω without abnormal impedance, and the counterpart of photo resist mask was 0.27~0.29Ω , with a difference of 0.027Ω, very minor, which can be obtained that metal layer derived from carbon-based hard mask won’t lead to open circuit problem that caused by excessive resistance. Therefore, carbon-based hard mask can improve the etched lithography pattern reso-lution without additional energy consumption.