Browse Prior Art Database

GLOBAL ILD PLANARITY WITH A LOW DIELECTRIC CONSTANT POLYIMIDE

IP.com Disclosure Number: IPCOM000006314D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2001-Dec-24
Document File: 2 page(s) / 84K

Publishing Venue

Motorola

Related People

Willis Goodner: AUTHOR [+2]

Abstract

This invention simplified the process used to achieve global planarity of polyimide tihns used as insulating layers in multilayer metal devices. In addition, global planarity can be achieved with new low dielectric con- stant polyimide formulations by integrating these mate- rials with existing process technology.

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MOTOROLA INC. Technical Developments Volume 14 December1991

GLOBAL ILD PLANARITY WITH A LOW DIELECTRIC CONSTANT POLYIMIDE

by Willis Goodner and David I?. Rodgers

A. PURPOSE

  This invention simplified the process used to achieve global planarity of polyimide tihns used as insulating layers in multilayer metal devices. In addition, global planarity can be achieved with new low dielectric con- stant polyimide formulations by integrating these mate- rials with existing process technology.

B. PROCESS

1. The metal pattern is etched and the photoresist is removed (Figure 1).

2. Photosensitive polyimide of a thickness (after cure) equal to the step height of the metal features is applied.

3. The polyimide is patterned using a photomask that is a moditied reverse image of the metal pat- tern. Polyimide plugs or islands are lefi between the widely spaced (> 5~) metals features (Figure
2). Plugs are not present between tightly spaced (-z 5p). The plugs will consist of commercialIy avail- able photosensitive polyimide. The dielectric con- stant ofthis material is not critical because the true ILD will be applied in a following step.

4. A low dielectric constant polyimide layer is then

applied (Fire 3). This will be the ILD separating the underlying metal and the subsequently deposited metal. This material is also present between the tightly spaced metal features of the underlying metal layer.

NEW STBUCTURAL ELEMENTS

1. The use of photosensitive polyimide to form plugs bet...