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Method for CPU Socket pin modification for reducing fillet cracking

IP.com Disclosure Number: IPCOM000020303D
Publication Date: 2003-Nov-12
Document File: 2 page(s) / 57K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for CPU Socket pin modification for reducing fillet cracking. Benefits include improved reliability.

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Method for CPU Socket pin modification for reducing fillet cracking

Disclosed is a method for CPU Socket pin modification for reducing fillet cracking. Benefits include improved reliability.

Background

         As the packaging is becoming miniaturized, the dimensions of CPU socket technology are reduced. To improve the input/output (I/O) tapeout, the surface-mount technology (SMT) socket is implemented with solder ball interconnection. This approach presents reliability and manufacturability problems. The joints between the solder balls and socket pins can crack when subjected to test fixture pressure or thermal-mechanical stress during reliability testing. This cracking is conventionally prevented by removing the external stress, pressure, or force.

         The conventional design of the pin in the CPU socket is a single outward-direction curve (see Figure 1).

General description

The disclosed method is a redesign of the pin shape in the central processing unit (CPU) socket to reduce the stress point of the solder joint. With the shape change, fillet cracking during board assembly processing and reliability testing is eliminated.

         The disclosed method changes the design of the pin to a dual directional curve (see Figure 2) to eliminate the weak solder joint point where the thin layer of solder fillet is formed.

Advantages

         The disclosed method provides advantages, including:

•         Improved reliability due to better socket performance because of a stronger solder joint

Fig. 1

Fig. 2

Disclosed a...