Browse Prior Art Database

Etchant for Copper Underlayer

IP.com Disclosure Number: IPCOM000046207D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Mancey, S: AUTHOR [+2]

Abstract

A terminal metallurgy comprises a first layer of Cr deposited on a substrate such as semiconductor substrate or ceramic substrate, a second layer of Cr/Cu on the first layer, a third layer of Cu and an overlying layer of Au. The third and overlying layers are partly etched to measure the thickness of Au and Cu layers. KI + I2 solution is used for etching the Au layer, and ammonium persulfate is used for etching the Cu layer.

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Etchant for Copper Underlayer

A terminal metallurgy comprises a first layer of Cr deposited on a substrate such as semiconductor substrate or ceramic substrate, a second layer of Cr/Cu on the first layer, a third layer of Cu and an overlying layer of Au. The third and overlying layers are partly etched to measure the thickness of Au and Cu layers. KI + I2 solution is used for etching the Au layer, and ammonium persulfate is used for etching the Cu layer.

In the conventional method, the KI + I2 solution has been used to etch both Au and Cu layers. Since this iodide solution also etches Cr, difficulty has been experienced in etching only Au and Cu layers.

In accordance with the present method, after the Au layer is etched by iodide solution in the unmasked area, the exposed Cu layer is etched by ammonium persulfate which is found not to etch the underlying Cr/Cu layer. Thus, the cross- section of the Au and Cu layers is accurately and reproducibly exposed for measurement.

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