Method of etching etch-resistant materials
US4713145A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1986 |
| Grant date | Dec 15, 1987 |
| Priority date | — |
| Expiry date | Dec 19, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/31111
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method for etching sapphire and other etch-resistant materials is disclosed. The method consists of preparing a hot, precipitated-gel form of phosphoric acid solution and immersing the item to be etched in the hot, precipitated-gel. The gel is prepared by heating a liquid phosphoric acid solution, causing water contained in the solution to evaporate. As the water evaporates, the solution thickens and eventually attains the precipitated-gel state. The etching rate of a sapphire wafer immersed in the gel is on the order of 10-50 microns per hour, depending on the depth of immersion, the orientation of the wafer and the temperature of the gel.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.