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US 5,849,680 AGranted
Cleaning with limonene, BHT, and acetylacetonate
AssigneeLucent Technologies Inc.
InventorChing-Ping Wong
Life of this patent
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Abstract
The specification describes a cleaning process for electronic devices and assemblies such as printed wiring boards. In the cleaning process deterioration of a terpene based cleaning solution, as evidenced by yellowing, is prevented using a copper chelating additive.
Claims1
A method for cleaning a printed wiring board which contains copper interconnections the method comprising the steps of exposing the printed wiring board to a cleaning solution, and rinsing the cleaning solution from the printed wiring board, said cleaning solution comprising:
- - 95weight % of a terpene selected from the group consisting of d-limonene, 1-limonene, and dipentene,
- 0.05-1.0% 2,6-di(t-butyl)-4-methyl-phenol, and
- 1.2-5.0 weight % of acetylacetonate.
Dependencies are inferred from the claim text.