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Browse Prior Art Database

Magnetic Stencil Paste Screening Method

IP.com Disclosure Number: IPCOM000120936D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 37K

Publishing Venue

IBM

Related People

Hart, PJ: AUTHOR [+4]

Abstract

Disclosed is a system in which stencil separation from part during screening resolution is experienced when an electromagnetic vacuum chuck and a ferromagnetic stencil are used together. This separation occurs during conventional screening which uses a non- ferromagnetic stencil and a vacuum chuck. The separation allows paste to flow beneath the stencil causing defects such as voids, smear, shorts, and opens.

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

Magnetic Stencil Paste Screening Method

      Disclosed is a system in which stencil separation from part
during screening resolution is experienced when an electromagnetic
vacuum chuck and a ferromagnetic stencil are used together.  This
separation occurs during conventional screening which uses a non-
ferromagnetic stencil and a vacuum chuck.  The separation allows
paste to flow beneath the stencil causing defects such as voids,
smear, shorts, and opens.

      In the illustration, the PART #1 is placed onto the
Electromagnetic Vacuum Chuck #2 prior to screening paste. Vacuum is
applied "on" holding part flat as the Ferromagnetic Stencil #3 is
lowered for alignment to the part.  Once alignment is complete, the
electromagnet can be turned "on" drawing the stencil tightly onto the
part while the Screening Blade #4 deposits the Paste Material #5
through the stencil openings to the part.  After this step is
completed, the electromagnet is turned "off" allowing the
ferromagnetic stencil to be lifted away from the part.  The finished
part may now be removed after vacuum has been turned "off" completing
this process.

      Disclosed anonymously.