Browse Prior Art Database

Domed Solder Joints for Surface Solder Leads

IP.com Disclosure Number: IPCOM000062559D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Napp, D: AUTHOR

Abstract

The present cross-sectional geometry of surface solder leads results in the quantity of solder under the lead after reflow to be dependent upon many factors, e.g., solder screened/stenciled onto the pad, weight of the component, force exerted on the component during placement, fixture of component prior to reflow, etc. As a result of component and process variables, the quantity of solder is variable which produces a solder joint of variable strength. The quantity of solder under the lead can be increased and controlled by the design of the lead shown in Figs. 1 and 2. By reforming the lead to obtain a dome of solder under the lead a constant quantity of solder can be assured under the lead. This quantity of solder will assure a reliable solder joint for stress in the Z direction.

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Domed Solder Joints for Surface Solder Leads

The present cross-sectional geometry of surface solder leads results in the quantity of solder under the lead after reflow to be dependent upon many factors, e.g., solder screened/stenciled onto the pad, weight of the component, force exerted on the component during placement, fixture of component prior to reflow, etc. As a result of component and process variables, the quantity of solder is variable which produces a solder joint of variable strength. The quantity of solder under the lead can be increased and controlled by the design of the lead shown in Figs. 1 and 2. By reforming the lead to obtain a dome of solder under the lead a constant quantity of solder can be assured under the lead. This quantity of solder will assure a reliable solder joint for stress in the Z direction. By placing a hole in the lead, any gases which are generated during soldering can escape to assure that there are no solder voids in the fillet. Hence, the quantity of solder under the lead will be void-free and of a constant quantity.

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