Browse Prior Art Database

3D ADHESION USING VIA HOLES

IP.com Disclosure Number: IPCOM000009467D
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Aug-27
Document File: 2 page(s) / 82K

Publishing Venue

Motorola

Related People

Ian Hodgson: AUTHOR [+2]

Abstract

During solder reflow indiscriminate delamina- tion of thin FR4 to aluminum rigidizers (utilizing Pressure Sensitive Adhesive (PSA)) is an unaccept- able problem that requires stringent quality control with no valued added content. The current contain- ment is to bake all the laminations prior to use in a static oven at 120°C for three hours followed by a one hour cooling period with the oven door open.

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Page 1 of 2

MOTOROLA Technical Developments

8

3D ADHESION USING VIA HOLES

by Ian Hodgson and Steve Jordan

STATEMENT OF PROBLEM static oven at 120°C for three hours followed by a one hour cooling period with the oven door open.

  During solder reflow indiscriminate delamina-
tion of thin FR4 to aluminum rigidizers (utilizing CURRENT ADHESIVE TECHNOLOGY
Pressure Sensitive Adhesive (PSA)) is an unaccept-
able problem that requires stringent quality control This relies upon adhesive restraint in the X and with no valued added content. The current contain- Y planes only, while the Z plane relies only on the ment is to bake all the laminations prior to use in a strength of the adhesive. See Figure 1.

Fig. 1

PROPOSED SOLUTION a meniscus of adhesive to the inner edge of the hole(s). This will not only improve the bond in the By ensuring that existing via holes are clear (not X and Y, but will also in the Z direction thus making blocked with solder resist) and/or additional holes to the bond three dimensional rather than the current areas known to delaminate the PSA can flow into two dimensional. See Figure 2.
these holes during the lamination process and create

Triangle of 45" . .

. .

Fig. 2

% Molomla,lnc. 1999 106 September 1999

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Developments Technical m MOTOROLA

FURTHER ENHANCEMENTS rivet. See Figure 3. Also by clustering the holes into either triangle or diamond configurations addi-

  By increasing the PSA thicknes...