Browse Prior Art Database

Sealing System for Electronic Packages

IP.com Disclosure Number: IPCOM000120947D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 54K

Publishing Venue

IBM

Related People

Christiansen, RA: AUTHOR [+2]

Abstract

Disclosed is an alternative method of environmental and mechanical protection for use in "chip-on-board" electronic packaging. The principal improvement is the ability to rapidly process, in automated manufacturing, a protective chip covering which is readily removable and replaceable to facilitate economic post-sealing rework. (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 98% of the total text.

Sealing System for Electronic Packages

      Disclosed is an alternative method of environmental and
mechanical protection for use in "chip-on-board" electronic
packaging.  The principal improvement is the ability to rapidly
process, in automated manufacturing, a protective chip covering which
is readily removable and replaceable to facilitate economic
post-sealing rework.

                            (Image Omitted)

      This method is pictured in the drawing wherein a patterned
perimeter sealing 5 is deposited on top surface 2 of circuitized
substrate 1.  This can be by screening, stenciling, stamping, etc.
Following chip-on-board assembly 3 and test, a formed, flanged cover
is brought into contact with seal ring 5 and fused with heat and
pressure.  If rework is required, cover 4 can be removed mechanically
or thermo-mechanically, new seal ring material deposited and the
cover replaced after rework.

      The key to this processing is the usage of a seal ring
formulated from a copolymer that is selectively solvent- soluble and
heat sealable, for example (poly) Ethylene- Vinyl Acetate.  In the
proper polymer ratios, this copolymer can be solubilized with
specific selective solvents, be applied to substrate and subsequently
be heat sealed to form bonding. An added feature is to add conductive
fillers, thereby achieving electrical shielding over semiconductor
chip when combined with metal/metallized polymer covers.

      Disc...