Etching method
US11295960B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 2021 |
| Grant date | Apr 5, 2022 |
| Priority date | — |
| Expiry date | Mar 9, 2041 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/67109
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of etching a silicon oxide film with high precision at high selectivity as compared with a silicon nitride film while establishing both of a higher etching rate of the silicon oxide film and a lower etching rate of the silicon nitride film is provided. An etching method according to the present invention is directed to a dry etching method for etching a film structure without using plasma in which an end of a film layer having a silicon oxide film vertically sandwiched between silicon nitride films and laminated and formed in advance on a wafer disposed in a processing chamber forms a side wall of a groove or a hole while a processing gas is supplied into the processing chamber, the method including the steps of: supplying a hydrogen fluoride gas; cooling the wafer to a low temperature of −30° C. or lower, preferably, to −30 to −60° C.; and etching the silicon oxide film laterally from the end.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.