Investigation of ULSI Damascene Key Process-Process Integration of Cu/Temperature Difference Liquid Phase Deposition SiOF/Low K MSQ

• Main Authors: Yuh-Ching Su, 蘇育清
• Other Authors: Ching-Fa Yeh
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/11393592874921029016

碩士 === 國立交通大學 === 電子工程系 === 87 === To reduce RC delay, integration of Cu and low K dielectric is an important issue in future back end of line (BEOL) process. Owing to the etching by-products of Cu are hard to volatile, conventional Al metallization was replaced by Damascene process. However, after low K dielectric patterning, the dielectric will suffer O2 plasma damage during stripping, and result in K value increment and metal line corrosion. In thesis, to replace hard mask process, we propose a method of using TD-LPD FSG a MSQ's sidewall capping layer to avoid O2 plasma damage. This FSG has selective deposition characteristics i.e., it won't deposit on photoresist. Therefore, prior to photoresist stripping, we deposit this FSG on MSQ's sidewalls, then remove the photoresist. This method is more simple than hard mask process and compatible with dual Damascene process. This FSG exhibits low stress property owing to room deposition temperature. Besides, it has good isolating ability, which reduces leakage current between metal lines. The proposed method improves hard mask process and oxide linar process at one time. the film deposited at 25℃ with lowest K value (~3.4), lowest stress value ( ~41Mpa). Therefore, it is suitable to be used in BEOL process. Furthermore, The FSG with thickness ~12.7nm is adequate to withstand O2 plasma damage. Besides, we use N2O plasma annealing to enhance the moisture absorption resistance of the FSG. The dielectric etching process is very important in Damascene process. We found that The optimal MSQ etching recipe can be obtained by adjust CF4 flow rate and RF power value only. Finally, to remove MSQ sidewall polymer, we developed a technique with two-step treatment, and which won't damage MSQ. To sum up, we have developed a novel O2 plasma damage free Damascene process.