Chemical mechanical planarization method for thick copper films of micro-electro-mechanical systems and integrated circuits

Modern industries require more accurate and high power-efficient micro-electro-mechanical systems (MEMS) and integrated circuits (ICs). Because the structure of MEMS and ICs becomes complicated, chemical mechanical planarization (CMP) has been introduced to fabricate highly integrated electro-mechanical structures. This study aims to reduce dishing and erosion using a negative photoresist (PR) as a protective layer in CMP for thick copper. After bulk copper CMP, soft-landing was carried out using an acidic copper CMP slurry. Method I was the CMP of a thick copper pattern without a negative PR, and method II was a new concept for the CMP method which removed the copper and negative PR to reduce the amount of copper dishing and erosion. In comparison with method I, method II reduced the dishing and erosion buy about 46 and 60%, respectively.