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A Method of Controlled Spray Coating

IP.com Disclosure Number: IPCOM000103125D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 60K

Publishing Venue

IBM

Related People

Blais, C: AUTHOR [+5]

Abstract

This disclosure describes the design and use of a metal mask for controlled spray coating of a substrate to protect its circuits against corrosion. Because the coated substrate will be joined to an electronic component via, for instance, solder reflow, care must be taken to ensure that the critical joining areas of the substrate are not coated or contaminated during the coating process.

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This is the abbreviated version, containing approximately 75% of the total text.

A Method of Controlled Spray Coating

      This disclosure describes the design and use of a metal mask
for controlled spray coating of a substrate to protect its circuits
against corrosion.  Because the coated substrate will be joined to an
electronic component via, for instance, solder reflow, care must be
taken to ensure that the critical joining areas of the substrate are
not coated or contaminated during the coating process.

      Figure 1 shows a mask used for the spraying of an epoxy based
coating on a substrate.  During spraying, the side of the mask facing
up in Figure 1 is an intimate contact with the substrate which, in
turn, sits on a rubber platform. The alignment of the mask openings
relative to the substrate is achieved using the two alignment pins on
the mask (at positions E) and alignment holes in both the substrate
and the platform.  The openings, A and B, at the center of the mask
allow the liquid coating to access and coat the circuits on the
substrate.  The edges of these openings should be at a sufficient
distance away from the critical joining areas of the substrate.  This
distance depends on the geometries and arrangement of the circuits at
the edges of the mask openings as well as on the wetting behavior of
the liquid sprayed on the substrate.  The slot C by the mask openings
is created to prevent the liquid from traveling across the slot via
capillary actions.  The two wide slots D prevent the masks from
pressing on the sensitive co...