Sub-quarter-micron Al etching technology using SiON hard mask in transformer coupled plasma (TCP) etcher

Aluminum (Al) has been widely used as an interconnecting material for integrated circuits. As the manufacturing of integrated circuits moves toward sub-quarter-micron design rules, there is a strong need for Al etching process with thin Photo Resist (PR). This leads to even more challenging with more complicated Al etching schemes and smaller width of thicker Al line (<0.3 /spl mu/m). In order to meet the needs for tighter critical dimension (CD) control of Al line, higher selectivity of Al to PR and higher anisotropy, hard mask Al etching process was applied. In this study, SiON which is being used for Anti Reflective Coating (ARC) layer of Deep Ultra Violet (DUV) PR, was selected as a hard mask to Al etching, the feasibility of in-situ SiON hard mask and Al etching process was tested in TCP metal etcher. And also, it was investigated that the process parameters played an important role in the control of Al profile for 0.13/spl mu/m design rules.