CPEC Clean Enhancement via Backside Polishing to Reduce Precoat UPC Fault

The lifetime of the clampable protective ESC cover (CPEC) of the Novellus SPEED<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TM</sup> high-density plasma (HDP) chemical vapor deposition (CVD) tool has been investigated. It was found that backside average roughness (Ra) increases over time. This leads to helium leakage and causes universal pressure controller (UPC) faults. Although the cover is sent for recycling, its performance deteriorates as the recycling count increases. The backside R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> does not reduce significantly after cleaning. This results in high backside R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> in recycled covers. By polishing the backside of the cover, the R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> is greatly reduced. This improves the cover's survivability and reduces the precoat UPC fault rate. On a smoother surface, helium is well trapped due to the good contact between the cover and the ESC edge seal during the precoat deposition process. Fault trend results were gathered for 6 consecutive months. It was observed that once cleaned covers polished to lower R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> were installed in the tools, the precoat UPC fault rate reduced by 71.4 %. Typically, polishing the backside of the cover is effective in improving its reusability. It reduces the backside R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> to a low baseline. This allows for higher usage and lower failure rates.