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Protective Coating Process for Thin Film Processes

IP.com Disclosure Number: IPCOM000102465D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Busacco, R: AUTHOR [+5]

Abstract

This article describes a process that provides a layer of protective coating over circuitry on thin film packages.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 56% of the total text.

Protective Coating Process for Thin Film Processes

       This article describes a process that provides a layer of
protective coating over circuitry on thin film packages.

      Thin film packages, i.e., Blane 1.2, 2R, etc., require a
protective coating layer over the circuitry to prevent corrosion and
insulation resistance failures during temperature and humidity (T&H)
testing.  This disclosure provides a unique process to achieve this
goal.

      This process relates to the Blane 2R process, but is applicable
to any thin film package.  The following process applies after the
panel (or web) has been copper plated and the first-pass photoresist
has been stripped.
1.   Spray Polyimide - A coating of polyimide is applied over the
copper circuitry and becomes the layer of protective coating.
2.   Cure Polyimide - An oven cure to "B" stage the polyimide to
eliminate tackiness.
3.   Apply Photoresist - This can be a regular dry film hot roll
resist lamination process or may be a vacuum lamination process, if
necessary.
4.   Expose Photoresist - Standard expose operation to define window
areas to be etched away during KAPTON* etching.
5.   Develop Photoresist - Standard develop operation to remove the
photoresist from the window areas.  At this point, the cross section
of the ILB window area would look like this:
6.   KAPTON Etch - Standard KAPTON etch process.  This process will
etch away the polyimide protective coating layer as well as the
Kapto...