3 September 1998 Plasma etching of aluminum copper tungsten on titanium nitride and titanium
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Abstract
A multistep plasma process based on chlorine and nitrogen chemistry was developed, characterized and optimized to anisotropically etch the metal stack consisting of a thin titanium nitride ARC, aluminum copper tungsten over titanium nitride and titanium, using LRC single wafer metal etcher. The new process must produce selectivities of metal-to- resist and metal-to-oxide under layer (TEOS) better than 3:1 and 8:1, respectively. With the help of design of experiment techniques, multivariable factorial experiments were conducted to determine the optimal processes for the bulk metal etch, barrier metal layer and overetch steps. It was found that the key to control of the metal profiles, CD linewidth and oxide loss is the metal etch selectivities to resist and oxide. Increasing the chamber pressure and chlorine chemistry improves the metal-to-resist selectivity for the bulk etch step. Reducing pressure and increasing chlorine and nitrogen help minimize the CD linewidth and oxide loss during an overetch etch step. In addition, it was found that the changes in other variables such as RF power and BCl3 produce no significant effects on selectivities of metal to photoresist and TEOS oxide.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kim Dang, Kim Dang, } "Plasma etching of aluminum copper tungsten on titanium nitride and titanium", Proc. SPIE 3507, Process, Equipment, and Materials Control in Integrated Circuit Manufacturing IV, (3 September 1998); doi: 10.1117/12.324334; https://doi.org/10.1117/12.324334
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