Browse Prior Art Database

Polyimide Swelling Protection

IP.com Disclosure Number: IPCOM000100552D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Koblinger, O: AUTHOR [+2]

Abstract

The simple method described in this article prevents the swelling of polyimide which is used as an insulation between the individual metal layers to fabricate thin-film multilayer wirings.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Polyimide Swelling Protection

       The simple method described in this article prevents the
swelling of polyimide which is used as an insulation between the
individual metal layers to fabricate thin-film multilayer wirings.

      A wiring plane consisting of two metal layers is deposited on a
substrate such that the individual layers are redundant with respect
to defects.  The top metal layer is structured by a lift-off process.
 During the fabrication of the lift-off layer, the bottom metal layer
serves as a protective layer.  It prevents the solvent (such as N-
methylpyrrolidone), used to strip the lift-off photoresist, from
entering the underlying polyimide and thus causing defects in the
overlying metal layer.

      Typical defects in the polyimide, such as wide and narrow
trenches, funnel-shaped scratches, and particles on the polyimide,
are shown in Fig. 1.  Fig. 1 also shows how a sputtered metal film
deposits on those defects.  Sidewalls and corners at the base of the
trenches and scratches in the polyimide are covered less
satisfactorily as the aspect ratio increases.

      Films applied by chemical vapor deposition (CVD), such as low-
pressure CVD (LPCVD) or plasma-enhanced CVD (PECVD) have the property
of imaging surfaces in a conformal fashion, i.e., they deposit on
deep sidewalls and the base of trenches such that defects are
insulated throughout (Fig. 2A).

      As additional layers are undesirable in established processes,
they...