Method of chimical mechanical polishing for dielectric layers
US5449314A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1994 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Apr 25, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31053
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming a planarized dielectric layer includes depositing a dielectric material on a substrate with a dopant concentration that decreases with depth and then chemically mechanically polishing the doped dielectric material. During the chemical mechanical polishing process the polish rate will be relatively fast initially but will slow down as the lighter doped material is contacted. Global planarity and polish selectivity are improved because the dopant gradient will automatically slow down the polish rate in areas where the lighter doped material is contacted. The high points of the dielectric material will thus polish faster than the low points. In an alternate embodiment of the invention, an underlying layer is deposited below a dopant graded dielectric layer having a predetermined dopant concentration that decreases with depth. The underlying layer may be undoped or uniformly doped. During the chemical mechanical planarization process, the dielectric layer with the graded profile is substantially removed. This insures that subsequent process steps will not be affected by a planarized dielectric layer having a non-uniform dopant concentration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.