Method for etching dielectric layers with high selectivity and low microloading
US5843847A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1996 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Apr 29, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31116
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of etching a dielectric layer on a substrate with high etching selectivity, low etch rate microloading, and high etch rates is described. In the method, the substrate is placed in a process zone, and a plasma is formed from process gas introduced into the process zone. The process gas comprises (i) fluorocarbon gas for etching the dielectric layer and for forming passivating deposits on the substrate, (ii) carbon-oxygen gas for enhancing formation of the passivating deposits, and (iii) nitrogen-containing gas for etching the passivating deposits on the substrate. The volumetric flow ratio of fluorocarbon:carbon-oxygen:nitrogen-containing gas is selected to provide a dielectric to resist etching selectivity ratio of at least about 10:1, an etch rate microloading of <10%, and a dielectric etch rate of at least about 100 nm/min. Preferably, the volumetric flow ratio of fluorocarbon:carbon-oxygen:nitrogen-containing gas is selected so that the rate of formation of passivating deposits on the sidewalls of the freshly etched features is approximately equal to the rate of removal of the passivating deposits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.