Method of reducing carbon, sulphur, and oxygen impurities in a calcium-doped copper surface and semiconductor device thereby formed
US6444580B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 2000 |
| Grant date | Sep 3, 2002 |
| Priority date | — |
| Expiry date | Mar 6, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of fabricating a semiconductor device having contaminant-reduced calcium-copper (Ca—Cu) alloy surfaces formed on Cu interconnects by cost-effectively removing the contaminant layer and a device thereby formed. Contaminant removal from a Cu—Ca—X surface, where contaminant X=C, S, or O, is achieved by sputtering the Cu—Ca—X surface in an argon (Ar) atmosphere between the steps of (a) immersing the Cu interconnect surface into an electroless plating solution comprising Cu salts, Ca salts, their complexing agents, a reducing agent, a pH adjuster, and at least one surfactant for facilitating Ca-doping of the Cu interconnect material; and (b) annealing of the Ca—Cu alloy surface onto the underlying Cu interconnect material to form a Ca—Cu/Cu interconnect structure, whereby the sputtering step, under Ar, selectively and effectively removes contaminants from the Cu—Ca—X layer containing higher concentrations of C, S, or O, thereby minimizing the post-annealed contaminant level, and thereby producing a uniform Ca—Cu alloy surface (i.e., Cu-rich with 0.2-5% Ca) on the Cu interconnect material for maximizing Ca—Cu/Cu i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.