Low-pressure oxygen plasmas are commonly used in semiconductor industry for removing photoresist from the surface of processed wafers; a process known as plasma ashing or plasma stripping. The possible use of atmospheric-pressure plasmas instead of low-pressure ones for plasma ashing is attractive from the point of view of reduction in equipment costs and processing time. We present investigations of photoresist etching with an atmospheric-pressure plasma jet (APPJ) in helium gas with oxygen admixtures driven by radio-frequency power. In these experiments, the neutral, radical rich effluent of the APPJ is used for etching, avoiding direct contact between the active plasma and the sensitive wafer, while maintaining a high etch rate. Photoresist etch rates and etch quality are measured for a range of plasma operating parameters such as power input, driving frequency, flow rate and wafer temperature. Etch rates of up to 10 micron/min were achieved with modest input power (45 W) and gas flow rate (10 slm). Fourier Transform Infrared (FTIR) spectroscopy showed that the quality of the photoresist removal was comparable to traditional plasma ashing techniques.
|Title of host publication||Proceedings of the 67th Annual Gaseous Electronics Conference (GEC), 02-07 November 2014, Raleigh, North Carolina|
|Publication status||Published - 2014|
|Event||67th Annual Gaseous Electronics Conference, GEC2014, 2-7 November 2014, Raleigh, North Carolina, United States - Raleigh, United States|
Duration: 2 Nov 2014 → 7 Nov 2014
|Conference||67th Annual Gaseous Electronics Conference, GEC2014, 2-7 November 2014, Raleigh, North Carolina, United States|
|Period||2/11/14 → 7/11/14|
|Other||67th Gaseous ELectronics Conference (67th GEC)|