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US 5,182,029 AGranted
Aqueous photoresist waste treatment by acid/cupric chloride precipitation
AssigneeInternational Business Machines Corporation
InventorAllen J. Erb
Life of this patent
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Abstract
A process is disclosed for treating an aqueous waste stream containing a photoresist waste component. Under this process the pH of the waste stream is adjusted in a range from about 4.0 to about 6.0 and an additive is added to the waste stream in a concentration effective to separate a precipitant from the waste solution in the form of a non-sticky residue. The additive is selected from the group consisting of FeCl.sub.3, CuCl.sub.2, NH.sub.4 Cl, AlCl.sub.3, and combinations thereof.
Claims5
A process for treating an aqueous waste stream containing a photoresist waste component which comprises the steps of:
- adding an acid solution containing cupric chloride in a concentration of at least 1.0 gram per liter to the waste stream to lower the pH of the waste stream;
- stopping the step of adding the acid solution after the photoresist waste components has separated from the aqueous waste stream as a precipitate;
- and
- removing the precipitate from the waste stream.
1 more element
Dependencies are inferred from the claim text.