Browse Prior Art Database

Buffer Layer for Via Hole Etching in Insulators

IP.com Disclosure Number: IPCOM000089410D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ahn, KY: AUTHOR [+4]

Abstract

Current magnetic bubble devices require sputter-deposition of an electrical insulator, such as SiO(2) and EE-9 glass, to separate layers of metallic conductors. To provide contacts, via holes are etched through the insulation layer in selected areas. Insulation layers prepared by RF sputtering of EE-9 glass have been found to possess excellent dielectric properties, but there is a problem in chemical etching of via holes when they are deposited onto gold (Au) films. In particular, a residue of the glass is left in the etched area of a via hole.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 68% of the total text.

Page 1 of 1

Buffer Layer for Via Hole Etching in Insulators

Current magnetic bubble devices require sputter-deposition of an electrical insulator, such as SiO(2) and EE-9 glass, to separate layers of metallic conductors. To provide contacts, via holes are etched through the insulation layer in selected areas. Insulation layers prepared by RF sputtering of EE-9 glass have been found to possess excellent dielectric properties, but there is a problem in chemical etching of via holes when they are deposited onto gold (Au) films. In particular, a residue of the glass is left in the etched area of a via hole.

The incomplete etching is caused by reaction products formed at the glass/gold interface during RF sputtering. Under normal conditions of device processing, the 1 Micron thick EE-9 glass layer requires up to three hours of sputtering, during which the film surface can reach a temperature as high as 350 Degrees C. At such a high temperature, kinetic reactions at the glass/gold interface can readily occur. To prevent these interfacial reactions, it is proposed to incorporate a thin metallic buffer layer. This buffer layer should be a good diffusion barrier to prevent Au from diffusing through it and interacting with the glass layer. It is also desirable to be able to use the buffer layer to improve the adhesion at the glass/gold interface.

Permalloy (NiFe) and Ti films of several hundred angstroms thickness serve as excellent buffer layers. Via holes have been successfully etch...