Browse Prior Art Database

Integral Mask for Paste Apply

IP.com Disclosure Number: IPCOM000121173D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Duffy, TP: AUTHOR [+3]

Abstract

Disclosed is a method in which an existing copper cover sheet is converted into a paste screening stencil by photo processing the copper. This invention significantly reduces the problems associated with conventional screening, such as misregistration of stencil, underflow of paste beneath stencil, and dielectric degradation or damage which may occur when processing cores without the protection of a cover sheet.

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This is the abbreviated version, containing approximately 100% of the total text.

Integral Mask for Paste Apply

      Disclosed is a method in which an existing copper cover sheet
is converted into a paste screening stencil by photo processing the
copper.  This invention significantly reduces the problems associated
with conventional screening, such as misregistration of stencil,
underflow of paste beneath stencil, and dielectric degradation or
damage which may occur when processing cores without the protection
of a cover sheet.

      Illustration (A) shows the core laminated with dielectric,
being protected by a copper cover sheet on top and bottom.  In (B)
the cover sheet is photo processed (resist/expose/develop/ etch/
strip) into a paste screening stencil.  In (C) dielectric is drilled
by laser and in (D) paste is applied forming circuitization to the
core.  In (E) cover sheet is etched off allowing further processing.

      Disclosed anonymously.