Sulfate-free electroless copper plating baths
US5306336A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1992 |
| Grant date | Apr 26, 1994 |
| Priority date | — |
| Expiry date | Nov 20, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C18/405
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Sulfate-free electroless copper baths comprising cupric ions, formaldehyde, formate ions, hydroxyl ions, a copper counterion, e g. preferably a monovalent anion such as acetate, nitrate or formate, and copper chelant such as an alkali metal salt of aminotris(methylenephosphonic acid), biscarboxymethylaspartic acid, ethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), gluconic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, mucic acid, D-saccharac acid, tartaric acid and N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine are amenable to the recovery of copper, e.g. from purge streams, using the methods and apparatus including solvent extraction, e.g. employing hydroxamic acid extractants, anion filtration, ion-exchange and chelant precipitation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.