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1. (WO2001035073) AUTOMATIC ETCHANT REGENERATION SYSTEM WITH HIGHLY ACCURATE SENSOR FOR MONITORING ETCHANT COMPOSITION

Pub. No.:    WO/2001/035073    International Application No.:    PCT/US2000/020856
Publication Date: Fri May 18 01:59:59 CEST 2001 International Filing Date: Fri Jul 28 01:59:59 CEST 2000
IPC: C23F 1/46
G01N 21/05
G01N 21/31
Applicants: OXFORD, V. U. E., INC.
CULPOVICH, Philip
FLYNN, David
Inventors: CULPOVICH, Philip
FLYNN, David
Title: AUTOMATIC ETCHANT REGENERATION SYSTEM WITH HIGHLY ACCURATE SENSOR FOR MONITORING ETCHANT COMPOSITION
Abstract:
A highly accurate sensor for monitoring the color density of various etchants in etchant regeneration systems is disclosed. The sensor comprises a Pyrex or equivalent tubular sensing chamber (1) and a light cell housing surrounding a portion of the chamber (1). The chamber (1) contains a rodlike extension (2) extending into the interior of the chamber (1). The housing accommodates a light source (5), preferably an LED or laser, and a photodetector (7), optically coupled through an aperture in the housing. Two such sensors are used in a regeneration apparatus attached to an etching machine used for etching copper, iron, stainless steels or other materials. In another embodiment, multiple sensors are used to detect multiple constituents of the etchants depending on the material being etched and the etchant used. A system employing two sets of sensors is particularly applicable to etchants that pass one color of light well when fully regenerated and another color of light well when fully spent.