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Polyimide-Siloxane as Corrosion Inhibitor for Pins

IP.com Disclosure Number: IPCOM000122097D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Booth, RB: AUTHOR [+3]

Abstract

Disclosed is a method of protecting the base of the pins (which have been brazed on to a ceramic substrate) with a film of polyimide-siloxane (SP53) material. The SP53 film 1 is spanned in a holder 2, and punch holes 3 are punched with a programmable punch to match the position of the pins 4. The film 1 can be aligned manually over the pins 4, and forced down so that the pins punch through the film at the hole positions. Then, a block 5 of Teflon with matching (oversize) holes 6 can force the film down further on the pins as shown in the diagram. If this setup now placed in a vacuum chamber to remove the air, and the Teflon pressed down further and the setup heated past the glass transition temperature of the film 1 (120oC for SP53), the film will stick to the substrate 7 material and the base of the pins.

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Polyimide-Siloxane as Corrosion Inhibitor for Pins

      Disclosed is a method of protecting the base of the pins (which
have been brazed on to a ceramic substrate) with a film of
polyimide-siloxane (SP53) material.  The SP53 film 1 is spanned in a
holder 2, and punch holes 3 are punched with a programmable punch to
match the position of the pins 4. The film 1 can be aligned manually
over the pins 4, and forced down so that the pins punch through the
film at the hole positions.  Then, a block 5 of Teflon with matching
(oversize) holes 6 can force the film down further on the pins as
shown in the diagram.  If this setup now placed in a vacuum chamber
to remove the air, and the Teflon pressed down further and the setup
heated past the glass transition temperature of the film 1 (120oC for
SP53), the film will stick to the substrate 7 material and the base
of the pins. Letting air back into the chamber will then force the
remaining film into intimate contact with the substrate 7 and pins 4,
letting no space remain for a film of liquid water which would
corrode the braze metallurgy holding the pins to the substrate.  The
SP53 is very soluble in xylene, so it can be removed easily for chip
rework.  SP53 film has low H2O permeability and absorption.

      Disclosed anonymously.