Browse Prior Art Database

Double Insulator Via Etch Process

IP.com Disclosure Number: IPCOM000036069D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Hoerner, E: AUTHOR [+2]

Abstract

The use of a nitride layer as an auxiliary layer, overlying a polyimide layer, in conjunction with a specific etch sequence by a single mask process considerably simplifies and improves the generation of contact holes in a nitride/polyimide double-layer insulation. (Image Omitted)

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Double Insulator Via Etch Process

The use of a nitride layer as an auxiliary layer, overlying a polyimide layer, in conjunction with a specific etch sequence by a single mask process considerably simplifies and improves the generation of contact holes in a nitride/polyimide double-layer insulation.

(Image Omitted)

The etch process is described by means of the polyimide/nitride insulating layer sequence, providing for the following layers to be successively applied to the wafer (Fig. 1A) a silicon nitride insulating layer,

a polyimide insulating layer,

a silicon nitride auxiliary layer, and

a thin photoresist layer (< 1 mm - suitable for

E-beam exposure).

The photoresist is exposed through the via mask and developed. The holes are transferred to the underlying nitride/polyimide/nitride layers. The dimensions (diameters of the contact holes in the nitride insulating layer) are defined by holes previously produced in the nitride auxiliary layer (Figs. 1A to 1F). Oblique side walls of the vias in the upper portion of the polyimide layer are obtained by using suitable RIE parameters (Figs. 1C to 1D). The photoresist is removed during the etching of the polyimide. The nitride auxiliary layer is removed in situ during the etching of the contact hole in the nitride insulating layer (Fig. 1E). The thickness of the nitride auxiliary

(Image Omitted)

layer defines the height of the first double step in the insulating nitride. Edges, if any, in the polyimide layer are rounded...