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An Alternate Via Plugging Apparatus for Printed Wire Boards

IP.com Disclosure Number: IPCOM000008482D
Publication Date: 2002-Jun-17
Document File: 2 page(s) / 65K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that uses a partial cap during wave soldering to keep the connected BGA joint temperature below 165C. Benefits include the elimination of voids and shorts.

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An Alternate Via Plugging Apparatus for Printed Wire Boards

Disclosed is a method that uses a partial cap during wave soldering to keep the connected BGA joint temperature below 165C. Benefits include the elimination of voids and shorts.

Background

Currently, no cap is used on the backside of the BGA joint; while this approach creates a good joint, it does not work with motherboards that must pass through wave soldering. With standard BGA via in pad processing, the joint formed on the via is capped with a solder mask (or other material) that tends to outgas in reflow. This leads to voids, and in the worst case, shorts.

General Description

The disclosed method uses a partial cap to keep the connected BGA joint temperature below 165C. This cap has a hole in its center, providing thermal protection as well as consistent joint standoff through venting. The vent can be constructed in many ways. Figure 1 shows four or more joints formed with materials that do not melt in reflow; these provide BGA joint standoff height control.

Advantages

The disclosed method eliminates voids and shorts in the BGA via in pad processing, and

greatly reduces yield loss.

Fig. 1

Disclosed anonymously