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Browse Prior Art Database

Stacked Surface Mount Component Solder Joints

IP.com Disclosure Number: IPCOM000037886D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-30
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Koons, JP: AUTHOR

Abstract

Stacking of components is often used in memory packages to increase density. Typically, the leads of the top module are soldered or welded to the leads of the bottom. The bottom module leads are then surface soldered to printed circuit card lands. If the bottom lead is open, the top lead will also be open. An open circuit is the primary quality and reliability problem.

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Stacked Surface Mount Component Solder Joints

Stacking of components is often used in memory packages to increase density. Typically, the leads of the top module are soldered or welded to the leads of the bottom. The bottom module leads are then surface soldered to printed circuit card lands. If the bottom lead is open, the top lead will also be open. An open circuit is the primary quality and reliability problem.

The disclosed design and process improves the quality and reliability of the joints by providing redundant paths into both the top and bottom leads.

In the figure, the leads of the top component (1) are formed in a "Gull Wing" shape and those on bottom (2) in a "J-Lead" shape. The leads of the top component (1) are soldered (3) or welded to those of the bottom (2) with co- planar bottom surfaces. This stack is then soldered (4) to the card lands (5). An electrical connection is made between the card land and each lead and between the leads of components (1) and (2). Redundant paths are thus provided into both the top and bottom leads.

Alternatively, a single process could be used to solder component (1) leads to those of component (2) and simultaneously solder both to land (5).

Disclosed anonymously.

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