Browse Prior Art Database

Simultaneous Contact/Planarization Etch Process

IP.com Disclosure Number: IPCOM000036139D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 97K

Publishing Venue

IBM

Related People

Pickens, MW: AUTHOR [+3]

Abstract

Currently, in semiconductor processing that requires planar passivation layers, planarization and contact etch are carried out in separate processing. The passivation layer is first planarized using one of the commonly available techniques, i.e., polishing or planarizing coatings and subsequent etch. This process is then followed by the contact definition process, which consists of a complete photo and etch process. (Image Omitted)

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Simultaneous Contact/Planarization Etch Process

Currently, in semiconductor processing that requires planar passivation layers, planarization and contact etch are carried out in separate processing. The passivation layer is first planarized using one of the commonly available techniques, i.e., polishing or planarizing coatings and subsequent etch. This process is then followed by the contact definition process, which consists of a complete photo and etch process.

(Image Omitted)

This article describes novel application of a single photo and etch process that will both planarize the passivation layer and etch the contacts through the passivation layer.

First, a layer of 1.5 microns of the passivation material is deposited (LTO on approximately 0.6 to 0.7 microns of topography), on patterned wafers as shown in Fig. 1. The wafers are then coated with an appropriate thickness of planarizing photoresist. The resist is patterned with contact mask lithography for that passivation layer. The cross-section of the processing thus far is shown in Fig. 2. Pilot holes are etched in the oxide layer for dimensional control and definition using an anisotropic oxide etch with a high selectivity to resist to a depth of 0.2 to 0.3 microns. The conditions for such an etch are commonly used and well understood and are as follows: CHF3 Flow = 8 SCCM; O2 Flow = 77 SCCM; DC BIAS = -550 V; Pressure = 50 mTorr. Fig. 3 depicts the cross-section after this step.

(Image Omitted)

The height of the resist may be reduced by 0.4 to 0.5 microns with an anisotropic O2 RIE. This is to enable the deposited thickness of the passivation layer to be kept to a minimum without danger of etching through to the underlying struc...