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Dual-Function Solder Procedure

IP.com Disclosure Number: IPCOM000051335D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Lau, JA: AUTHOR [+2]

Abstract

In electronic circuit package components of the flat pack and lead fram types, the input/output (I/O) leads are connected by a common frame-like member. This member, known as a selvage strip, is usually made of the same material stock as the leads. It maintains the positions of the leads in the same plane and in alignment during subsequent processing of the component preparatory to the bonding of the component leads to the compatibly registered printed circuit (PC) pads of the PC board or card to which the component is to be mounted. The current practice is to remove the selvage strip just prior to the lead/pad bonding operation, as it has been found to be more expensive and complex to remove the selvage strip after the bonding operation.

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Dual-Function Solder Procedure

In electronic circuit package components of the flat pack and lead fram types, the input/output (I/O) leads are connected by a common frame-like member. This member, known as a selvage strip, is usually made of the same material stock as the leads. It maintains the positions of the leads in the same plane and in alignment during subsequent processing of the component preparatory to the bonding of the component leads to the compatibly registered printed circuit (PC) pads of the PC board or card to which the component is to be mounted.

The current practice is to remove the selvage strip just prior to the lead/pad bonding operation, as it has been found to be more expensive and complex to remove the selvage strip after the bonding operation. Nonetheless, in the situation where the strip is removed prior to the bonding operation, the now free ends of the component leads are unprotected and easily deformed from their desired aligned positions.

The present procedure overcomes this difficulty. In the present procedure, prior to removal of the selvage strip, a length of wire solder, preferably a flux/solder combination, is fused to the individual leads at their respective bonding sites. The wire solder thus physically links, i.e., connects, the leads together so that when the selvage strip is then removed, the leads remain in their respective aligned positions. Moreover, the wire solder also becomes the solder source for the subsequent bond...