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T-Shaped Integrated Heat Spreader for Package Compliance

IP.com Disclosure Number: IPCOM000029159D
Publication Date: 2004-Jun-16
Document File: 3 page(s) / 61K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that increases the distance of an integrated heat spreader (IHS) anchoring point to the corners of a package. Benefits include reducing the rigidity of a package, as well as the solder joint reliability risk.

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T-Shaped Integrated Heat Spreader for Package Compliance

Disclosed is a method that increases the distance of an integrated heat spreader (IHS) anchoring point to the corners of a package. Benefits include reducing the rigidity of a package, as well as the solder joint reliability risk.

Background

Increasing power requirements will require future products to use an IHS. However, current packages with an IHS are very rigid, and have a lower bending energy compared to packages without an IHS (see Figure 1).  The following are the current state-of-the-art solutions to reduce the rigidity of packages with an IHS:

 

  • Adding a backing plate and stiffeners around the package; however, this solution increases the cost to customers (i.e. board manufacturers) and restricts the board design flexibility.
  • Depopulating the three corners joints at each package corner; however, there are still one to two rings of solder joints outside the I-HS.  The success of this solution has not been proven, and it may simply transfer the stress to the inner joints.
  • Changing the plating surface finish from ENIG (i.e. electroless nickel immersion gold) to DIG (i.e. direct gold); however, the change is unsuccessful, because DIG leads to tiny void problems and other package-level issues).

General Description

The disclosed method reduces the rigidity of the package, making it more board-compliant and reducing solder joint reliability risks. The disclosed method increases the distance of IHS anchoring points t...