Browse Prior Art Database

Producing Via Holes in Sputtered Quartz

IP.com Disclosure Number: IPCOM000080452D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Palagonia, AM: AUTHOR [+2]

Abstract

By this method, via holes can be made with tapered sidewalls.

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Producing Via Holes in Sputtered Quartz

By this method, via holes can be made with tapered sidewalls.

Via holes formed by etching techniques in conventionally sputtered quartz have the cross-sectional configuration illustrated in Fig. 1. The via hole 10 in layer 12 will normally have a relatively sharp upper edge 14, where the sidewalls meet the top surface of layer 12. These sharp edges, particularly when combined with steep sidewall surfaces, can lead to reduced thicknesses in via pads and interconnection metallurgy stripes in the step down.

With this method, a via opening 16, as illustrated in Fig. 2, can be produced. Via opening 16 in quartz layer 12 is produced by varying the etchable nature of the layer 18 as it is deposited. The major portion of the layer, i.e., the bottom portion, is produced by conventional sputtering. The top portion of the layer is deposited so that it will have a faster etch rate. This can be accomplished by reducing the resputtering rate by varying the conditions within the sputtering apparatus. A preferred technique for reducing the resputtering rate is to reduce the DC anode voltage, by varying the combined inductance and capacitance between the base plate and the anode, as explained in U. S. Patent 3,617,459. Conventional subtractive etching results in the via profile illustrated in Fig. 2.

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