Browse Prior Art Database

Photoactive Polyimide

IP.com Disclosure Number: IPCOM000051888D
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Blakeslee, MC: AUTHOR

Abstract

Polyimide is a dielectric material used in the fabrication of microelectronic device structures. In order to form patterns or vias in it, a secondary photoresist mask or an intermediate metal mask (which is itself patterned by a photoresist mask) is required.

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Photoactive Polyimide

Polyimide is a dielectric material used in the fabrication of microelectronic device structures. In order to form patterns or vias in it, a secondary photoresist mask or an intermediate metal mask (which is itself patterned by a photoresist mask) is required.

Chemical etching of thick polyimide requires multiple bake/etch steps due to the fact that the etchant attacks the photoresist mask as well as the polyimide itself.

In the case of dry etching, i.e., RIE (reactive ion etching), an intermediate metal mask, resistant to the reactive plasma, must be deposited and patterned prior to the patterning of the polyimide. This requires the use of a photoresist mask to pattern the metal, which then is used to pattern the polyimide.

In both these methods, the auxiliary masks must be removed after use, with the possibility of contamination of the polyimide dielectric by the solvents, as well as the possibility of residue being left after etching.

The process described here permits standard polyimides, such as Monsanto's SKYBOND or Dupont's PYRA, to be made photosensitive, i.e., those areas exposed to UV dissolve readily in the developer, or etchant, while the etch- rate of the unexposed areas is inhibited. This is accomplished by the addition to the polyimide of a photoactive compound.

Patterns have been defined in polyimide films up to 25 microns thick, in one application, using the following method: 1 part photo-active compound is dissolved in 2 par...