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Solder Build-Up Avoidance On Leads From Plastic Package

IP.com Disclosure Number: IPCOM000100926D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Schwenn, KW: AUTHOR [+2]

Abstract

To avoid solder build-up on leads next to plastic guard edges, solder drainage features are built into guard edge parts. Thus, trimming and forming leads is facilitated and trimmed leads are of uniform thickness at connectors.

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Solder Build-Up Avoidance On Leads From Plastic Package

       To avoid solder build-up on leads next to plastic guard
edges, solder drainage features are built into guard edge parts.
Thus, trimming and forming leads is facilitated and trimmed leads are
of uniform thickness at connectors.

      Referring to Fig. 1, plastic chip package 10 has leads 12
extending outward and fastened into guard edge 14. Region 16 is
enlarged in Fig. 2 which shows solder relief channels 18 in guard
edge 14.  Cross section B-B of Fig. 2 is shown in Fig. 3.  Relief
channels 18 on both sides of each lead 12 provide paths through which
molten solder may be drained or blown off without solder bridging
between leads 12.  Fig. 4 is a cross section B-B of Fig. 2, in which
the dashed lines show solder build-up which occurs when there are no
relief features, e.g., channels 18 of Figs. 2 and 3.  Solder 20 more
nearly uniformly coats leads 12 when solder blow-off or shake-off is
performed immediately after wave or dip solder application when
solder drainage features are incorporated in guard edge 14.