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Strain Relief Pins for Ball Grid Array

IP.com Disclosure Number: IPCOM000122920D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Garrity, J: AUTHOR [+2]

Abstract

Ball Grid Array (BGA) components are becoming more popular and the technology is also being expanded to include components such as connectors which are heavier and subject to more stress than normally seen on plastic packages. The corner contacts are the most vulnerable, and in order to reduce impact on reliability due to cracking, they are sometimes not connected electrically.

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Strain Relief Pins for Ball Grid Array

      Ball Grid Array (BGA) components are becoming more popular and
the technology is also being expanded to include components such as
connectors which are heavier and subject to more stress than normally
seen on plastic packages.  The corner contacts are the most
vulnerable, and in order to reduce impact on reliability due to
cracking, they are  sometimes not connected electrically.

      In the described solution, the corner balls are replaced, as
shown in Fig. 1, with pins which can be soldered into normal
plated-through holes in the printed circuit board.  These pins can be
placed into paste and, hence, be soldered at the same time as
soldering the rest of the ball grid array.  The pins also assist in
the alignment of the device to the pads which is more difficult in
heavy devices/components.  After soldering, these pins ensure a more
robust attachment of the component to the card and, therefore, take
the strain if heatsinks are attached or mechanical force exerted when
plugging/unplugging a connector system.

      The increased mechanical strength of the pins means that these
connections may be used electrically in the device.  The length of
the pin is arranged, as shown in Fig. 2, to be less than the raw card
thickness so that it can be assembled during the first pass of the
process on a double sided printed circuit board.