THE EVALUATION OF HEXAFLUORO-1,3-BUTADIENE AS AN ENVIRONMENTALLY BENIGN DIELECTRIC ETCH CHEMISTRY IN A MEDIUM-DENSITY ETCH CHAMBER

摘要

In an effort to develop alternative etch chemistries with a reduced environmental footprint, hexafluoro-1,3-butadiene (C_4F_6) has been evaluated for global warming emissions and process performance on a medium-density etch chamber for both silicon oxide and organosilicate glass (OSG) films. The process and emissions results are compared to PFC-based processes. For oxide etching, global warming emissions reduction as high as 82% were attained compared to a c-C_4F_6-based process, with similar process performance achieved. For the c-C_4F_8 process, greater than 60% of the total emissions are due to unreacted c-C_4F_8, a high-GWP feed gas. By simply switching to a low-GWP gas like C_4F_6, the emissions from unreacted feed gas are eliminated. In addition the C)4F_6 process resulted in lower CHF_3 emissions, which is likely due to lower photoresist erosion, as photoresist is a source of hydrogen for the formation of CHF_3. In the case of OSG etching, 65% reduction in global warming emissions was possible compared to a c-C_4F_8 process, with comparable process performance.