Planarizing dielectrics for VLSI technology

In this paper we describe the first reported blanket removal properties of various dielectric films. Based on material selectivity, We deposited thin PEOX, thick BPSG and a hard dielectric film with lower removal rate on top of a patterned wafer. Initial polishing removed the top hard dielectric level completely, exposing the BPSG, but the lower hard material remains less polished, BPSG polishes faster than hard dielectric film, resulting that the BPSG level was selectively polished. After the completion of the process with over etch, the height variation of 5mm scan range is less than 60 nm.