Browse Prior Art Database

Differential Curing of Polyimide and Photosensitive Polyimide

IP.com Disclosure Number: IPCOM000104039D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 33K

Publishing Venue

IBM

Related People

Lee, K: AUTHOR

Abstract

Disclosed is a method to improve reliability of the multilevel packages in which photosensitive polyimide (PSPI) is employed. Polyimides and photosensitive polyimides are employed as dielectric layers in multilevel packaging. Various photoactive components (PACs) such as initiator, sensitizer and cross-linking agent are added to the PSPI formulation to enhance lithographic property. It is difficult to completely get rid of these photoactive components in the process. If the temperature is raised in the next curing process, the molecular motions and relaxations bring the photoactive components to the interface and thus, adhesion between two phases becomes weaker. If the PACs are decomposing and thus, evaporating, the outgassing materials will be trapped at the interface.

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Differential Curing of Polyimide and Photosensitive Polyimide

      Disclosed is a method to improve reliability of the multilevel
packages in which photosensitive polyimide (PSPI) is employed.
     Polyimides and photosensitive polyimides  are  employed as
dielectric layers in multilevel packaging.  Various photoactive
components (PACs) such as initiator, sensitizer and cross-linking
agent are added to the PSPI formulation to enhance lithographic
property.  It is difficult to completely get rid of these photoactive
components in the process.  If the  temperature is raised in the next
curing process, the molecular motions and relaxations bring the
photoactive components to the interface and thus, adhesion between
two phases becomes weaker.   If the PACs are decomposing and thus,
evaporating, the outgassing materials will be trapped at the
interface.  This phenomenon may cause blistering or interfacial
failure.
     The  polyimides  and  photosensitive  polyimides can be
differentially cured in the multilevel packaging processes.  If  the
curing  temperature of the next layer is lower, the molecular motions
and relaxations of the PACs left in the film can be reduced.  Thus, a
possible decrease of the adhesion strength can be minimized.  The
PACs coming to the surface of the first layer by curing will be
evaporated or removed by a surface modification stage.  From the
second layer, the curing temperature is lowered by 1-10ºC.
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