Process for preventing corrosion of aluminum bonding pads after passivation/ARC layer etching
US5930664A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1997 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Jul 24, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/976
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for etching access opening to aluminum alloy wire bonding pads of integrated circuit chips is described wherein a polymer layer is in-situ deposited into the opening after the bonding pad has been exposed by dry etching of a passivation layer. The passivation layer, is first etched with fluorocarbon etchants and then a TiN ARC layer is removed from over the aluminum bonding pad with etchants which may contain chlorine either as etch components or as a contaminant in an etchant such as SF.sub.6 non-volatile chlorine containing residues including AlCl.sub.3 and trapped Cl.sub.2, are left behind after the ARC layer has been removed. These cause corrosion of the bonding pad when exposed to atmospheric moisture. The polymer layer deposited immediately after the pad surface is exposed by the etchant, provides a temporary seal over the aluminum bonding pad, protecting it from exposure to moisture during subsequent processing steps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.