Method of selectively etching silicon dioxide dielectric layers on semiconductor wafers
US5300463A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | Mar 6, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31111
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of utilizing and etching SiO.sub.2 in the processing of semiconductor wafers comprises: a) providing a layer of undoped SiO.sub.2 atop a wafer; b) providing a layer of doped SiO.sub.2 atop the layer of undoped SiO.sub.2 ; and c) wet etching the layer of doped SiO.sub.2 selectively relative to the undoped layer of SiO.sub.2 utilizing an acid solution, the acid solution comprising a mixture of at least two different mineral acids provided in a selected ratio relative to one another, one of the mineral acids being HF. The preferred volumetric ratio of other mineral acids in the acid solution to HF in the acid solution is from 20:1 to 110:1, with a ratio of from 45:1 to 65:1 being most preferred. Example acids to be combined with the HF include H.sub.2 SO.sub.4, HCl, HNO.sub.3, H.sub.3 PO.sub.4, HBr, HI, HClO.sub.4, and HIO.sub.4, or mixtures thereof.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.