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Browse Prior Art Database

Selective Laser Etching of Chromium - Dry Process

IP.com Disclosure Number: IPCOM000060607D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lankard, JR: AUTHOR [+2]

Abstract

This article describes a dry process procedure that produces the selective removal of desired portions of a chromium metal layer with the use of an excimer laser. The procedure does not require the use of a resist mask to produce the desired pattern.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 93% of the total text.

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Selective Laser Etching of Chromium - Dry Process

This article describes a dry process procedure that produces the selective removal of desired portions of a chromium metal layer with the use of an excimer laser. The procedure does not require the use of a resist mask to produce the desired pattern.

In conventional semiconductor manufacturing a substrate has a top layer of chromium, and then a layer of copper and a non- reactive gas (SF6). In the disclosed dry etch process, the total assembly is put in an atmosphere of sulphur hexafluoride gas, which is the ambient reactive gas. An excimer laser is focused on the assembly. The chromium layer then absorbs the energy of the eximer laser and becomes heated. The heated chromium is in contact with the ambient reactive gas (SF6) sulfur hexafluoride. The gas disassociates and the the molecules react with the chromium to form chromium fluorides which are driven off by the energy of the laser. When the process has etched through the chromium layer, the copper layer is then exposed. The presence of fluorides passivates the surface of the exposed copper layer and the etching process is inhibited. This phenomenon contributes to the self-terminating characteristic of the disclosed process. The disclosed process is completely dry and does not require a wash operation after etch. The power of the laser and the density of the ambient gas effect the rate of the etch process. Since the reactive gas (SF6) is chemically bound in a s...