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Apparatus to Measure Etch Rates and Etch Parameters

IP.com Disclosure Number: IPCOM000042628D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Angelo, RW: AUTHOR [+4]

Abstract

The kinetics of metal attack and dissolution by chemical etchants is dependent on many factors. Among these are etchant composition, metal substrate composition and morphology, liquid-metal interface conditions, and the presence of inhibitors, catalysts, air, etc. The usual methods of etching by spraying with or dipping in etchant presents a complex mechanism with these and other factors having an effect on the etch process. The apparatus described here has both practical and theoretical applications. For practical applications, a device to measure etch rates can be used to produce an electrical signal that can control an etching process and record an "inherent etch rate" dependent only on solution strength. The "inherent etch rate" will also be related to the time required to obtain an optimum etch of the circuit part.

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Apparatus to Measure Etch Rates and Etch Parameters

The kinetics of metal attack and dissolution by chemical etchants is dependent on many factors. Among these are etchant composition, metal substrate composition and morphology, liquid-metal interface conditions, and the presence of inhibitors, catalysts, air, etc. The usual methods of etching by spraying with or dipping in etchant presents a complex mechanism with these and other factors having an effect on the etch process. The apparatus described here has both practical and theoretical applications. For practical applications, a device to measure etch rates can be used to produce an electrical signal that can control an etching process and record an "inherent etch rate" dependent only on solution strength. The "inherent etch rate" will also be related to the time required to obtain an optimum etch of the circuit part. For theoretical applications, a device is required that can vary the flow rate of etchant over substrate in order to determine the effect of laminar flow, turbulent flow, and the resultant liquid boundary layer adjacent to the metal. This in turn will affect the etching rate and undercutting of photoresists. Different apparatus can be used to practice the present invention. The apparatus proposed herein consists of essentially three parts. The first part is a copper specific ion electrode, and the second part is a source of copper. The source of copper could, for example, be a copper sphere packed column or strips of copper laminate. The third part is a second copper specific ion electrode. The apparatus operates by passing the etchant past the first electrode, past the source of copper, and then past the second electrode....