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Method for a low-cost stamped integrated heat spreader design with solder for attachment to the substrate

IP.com Disclosure Number: IPCOM000008241D
Publication Date: 2002-May-29
Document File: 7 page(s) / 88K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a low-cost stamped integrated heat spreader (IHS) design with solder for attachment to the substrate. Benefits include improved thermal performance, improved reliability, and reduced defects.

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Method for a low-cost stamped integrated heat spreader design with solder for attachment to the substrate

Disclosed is a method for a low-cost stamped integrated heat spreader (IHS) design with solder for attachment to the substrate. Benefits include improved thermal performance, improved reliability, and reduced defects.

Background

      A conventional IHS is attached to a flip-chip CPU substrate (see Figure 1). The IHS has a full perimeter lip-sealing feature (see Figure 2).

      The conventional solder thermal interface material (TIM) assembly operation consists of the following steps (see Figure 3):

·        Sealant dispense

·        Flux die

·        Pick and place the solder perform on the die

·        Flux the IHS (copper metal Ni plating and selective gold plating)

·        Pick and place the IHS and clip

·        Reflow solder and cure sealant (the substrate is adhered to the flat surface of the IHS lip with a polymer sealant)

General description

      The disclosed method utilizes low-cost, flat heat spreader designs that incorporate solder on the heat spreader cavity and as mechanical attachment features for flip-chip OLGA CPU applications. The heat spreader is attached to the die and substrate in one reflow operation.

              The key elements include:

·        Copper heat spreader with or without Ni plating

·        Stamping roll stock that contains copper in the center and solder TIM, such as indium, on one or more surfaces

·        Flat heat spreader stamped from roll stock with a copper core and a solder, such as indium, top layer

·        Solder stamped on the cavity of the IHS

·        Two or more stamped attachment pins with solder at the ends that attach to the substrate, or other attachment feature

·        Solder pins or other attachment features are formed in the stamping operation at minimal additional cost

 


Advantages

      The disclosed method provides advantages, including:

·        An IHS stamped with solder TIM and sealant in one operation

·        Large fl...