Single step CMP for polishing three or more layer film stacks
US8334190B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 2010 |
| Grant date | Dec 18, 2012 |
| Priority date | — |
| Expiry date | Jul 4, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A one-step CMP process for polishing three or more layer film stacks on a wafer having a multilayer film stack thereon including a silicon nitride (SiNx) layer on its semiconductor surface, and a silicon oxide layer on the SiNx layer, wherein trench access vias extend through the silicon oxide layer and SiNx layer to trenches formed into the semiconductor surface, and wherein a polysilicon layer fills the trench access vias, fills the trenches, and is on the silicon oxide layer. CMP polishes the multilayer film stack with a slurry including slurry particles including at least one of silica and ceria. The CMP provides a removal rate (RR) for the polysilicon layer > a RR for the silicon oxide layer > a RR for the SiNx layer. The CMP process is continued to remove the polysilicon layer, silicon oxide layer and a portion of the SiNx layer to stop on the SiNx layer. Optical endpointing during CMP can provide a predetermined remaining thickness range for the SiNx layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.