Method of removing metallic, inorganic and organic contaminants from chip passivation layer surfaces
US7771541B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2007 |
| Grant date | Aug 10, 2010 |
| Priority date | — |
| Expiry date | Feb 22, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/15311
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of removing and/or reducing undesirable contaminants removes residues including graphitic layers, fluorinate layers, calcium sulfate (CaSO4) particles, tin oxides and organotin, from a chip passivation layer surface. The method uses a plasma process with an argon and oxygen mixture with optimized plasma parameters to remove both the graphitic and fluorinated layers and to reduce the level of the inorganic/tin oxides/organotin residue from an integrated circuit wafer while keeping the re-deposition of metallic compounds is negligible. This invention discloses the plasma processes that organics are not re-deposited from polymers to solder ball surfaces and tin oxide thickness does not increase on solder balls. The ratio of argon/oxygen is from about 50% to about 99% Ar and about 1% to about 50% O2 by volume. Incoming wafers, after treatment, are then diced to form individual chips that are employed to produce flip chip plastic ball grid array packages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.