Multilayered CMP stop for flat planarization

摘要

A three layer film (116/114/112), such as nitride/oxide/nitride for a CMP stop layer (110). A gap filling material (120) is polished, stopping on the first film (112). The first film (112) is then stripped using an etch chemistry that is selective against removing the second film (114). CMP is then continued stopping on the third film (116).