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Method for an LGA socket body-stiffening feature

IP.com Disclosure Number: IPCOM000029162D
Publication Date: 2004-Jun-16
Document File: 3 page(s) / 154K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a land grid array (LGA) socket body-stiffening feature. Benefits include improved functionality and improved reliability.

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Method for an LGA socket body-stiffening feature

Disclosed is a method for a land grid array (LGA) socket body-stiffening feature. Benefits include improved functionality and improved reliability.

Background

      LGA sockets require an activation force on their contacts to create electrical contact and minimize electrical resistance. Load is generated directly through the load plate on an integrated heatsink shoulder to activate the contacts (see Figure 1).  However, a direct load generating device, such as a load plate, load lever, and stiffener plate, generates an excessive tensile load on corner solder balls without a heatsink load.

      This problem is conventionally solved by increasing the socket contact compliance, improving the socket contact paddle-to-solder ball bonding strength by optimizing the solder ball attachment process, and using larger solder balls. However, the tensile load remains as long as the stiffener plate displacement at the corners is not constrained.

      LGA sockets developed for desktop products are being adapted for server products. The direct load generating device used with LGA sockets puts the corner solder joints under tensile stress when no heatsink load is applied. This situation has been identified as a key contributor to early life solder-joint failures.

      Alternatively, to strengthen solder joints through reflow optimization, another solution is to further stiffener the corners of the stiffener plate as demonstrated by preliminary front-end analysis.

General description

      The disclosed method is an...