Method of AlF3 Defect Reduction using a Quartz Kit Configuration on AME5200 DPS Poly Si Etch Chamber
Original Publication Date: 2005-Oct-19
Included in the Prior Art Database: 2005-Oct-19
Aluminum fluoride defect contamination is an inherent problem associated with polysilicon etching on the AME5200 DPS platform. The defect generation stems from the ceramic kitting - the Al2O3 dome and ESC collar ring - that are directly impacted by the fluorinated plasma during RIE processing. Such metallic defects can impact the wafer/chip functionality physically, or electrically. Through utilization of a quartz chamber configuration and optimized recipe parameters, the nature of these defects is completely changed, eliminating the primary source of metallics in such poly etch processes.
Method of AlF3 Defect Reduction using a Quartz Kit Configuration on AME 5200 DPS Poly Si Etch Chamber
Polysilicon recess etching required for embedded DRAM technologies is typically done on an AME5200 DPS platform utilizing a ceramic (Al2O3) dome and collar ring around the ESC. This platform was originally intended for PC etching, but was later rejected due to high metallic defect counts found post etch. The DPS was later redeployed to the poly recess sector which had less sensitivity to metallics and/or defects in general. AlF defects are generated by the reaction of the fluorinated plasma and ceramic kit parts, which then fall back on the wafer before it exits the chamber, causing potential blockages in subsequent processing, and leakage/failure via metallic contamination at electrical test. However, this platform has been found to be superior to other AMAT models in poly etch in terms of lower defect density levels, better cross wafer uniformity, and in advanced platform features of the tool in general. This fact made it worthwhile to pursue a solution to this issue other than the vendor recommended change to a different etch platform.
Using a new chamber configuration, which replaces the main ceramic parts (dome/collar ring) with quartz, the primary sources of aluminum, which are the most significant contributors to AlF defect generation, are eliminated. The advantage of using quartz in place of the alumina parts is the nature of the defects will be completel...