Remote plasma nitridation for contact etch stop
US6140024A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1998 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Dec 18, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76834
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method is disclosed of nitridating an oxide layer (12) to form a stop layer for selective etching of sacrificial layer comprising the steps of, obtaining a wafer (10), forming a gate (30) on the wafer (10), depositing an oxide layer (12) on the wafer (10) and the gate (30), exposing the surface of the oxide layer (12) to a nitrogen ion containing plasma at, e.g., room temperature, wherein the nitrogen ions form a nitrided layer (22) on the oxide layer (12). Next, a silicate layer (32) is deposited on the nitrided layer (22), planarized and patterned with photoresist (14) for etching. The contacts or vias are then formed through the silicate layer (32) by etching down to the nitrided layer (22) that acts as a stop layer, followed by a second etching step that removes the nitrided layer (22). The photoresist (14) is then stripped and the silicon oxide layer (12) etch down to the wafer (10). The process of the present invention prevents the exposure of the wafer (10) to contaminants from the photoresist layer (14) and the etch chemicals that can deposit reactive radicals. These reactive radicals, also known as mobile ions, decrease the reliability of the device by contaminating subs…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.