Method for forming Co-W-P-Au films
US6323128A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1999 |
| Grant date | Nov 27, 2001 |
| Priority date | — |
| Expiry date | May 26, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for forming a quaternary alloy film of Co--W--P--Au for use as a diffusion barrier layer on a copper interconnect in a semiconductor structure and devices formed incorporating such film are disclosed. In the method, a substrate that has copper conductive regions on top is first pre-treated by two separate pre-treatment steps. In the first step, the substrate is immersed in a H.sub.2 SO.sub.4 rinsing solution and next in a solution containing palladium ions for a length of time sufficient for the ions to deposit on the surface of the copper conductive regions. The substrate is then immersed in a solution that contains at least 15 gr/l sodium citrate or EDTA for removing excess palladium ions from the surface of the copper conductive regions. After the pre-treated substrate is rinsed in a first rinsing step by distilled water, the substrate is electroless plated a Co--W--P film on the surfaces of the copper conductive regions in a first plating solution that contains cobalt ions, tungstate ions, citrate ions and a reducing agent. After the substrate coated with the Co--W--P film is rinsed in a second rinsing step by distilled water, the substrate is immersed in a second elec…
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