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Method for an integrated heat spreader package to control minimum sealant height

IP.com Disclosure Number: IPCOM000008244D
Publication Date: 2002-May-29
Document File: 3 page(s) / 79K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for an integrated heat spreader (IHS) package to control minimum sealant height. Benefits include improved thermal performance.

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Method for an integrated heat spreader package to control minimum sealant height

Disclosed is a method for an integrated heat spreader (IHS) package to control minimum sealant height. Benefits include improved thermal performance.

Background

              Substrate warpage of 3-4 mils during sealant cure has led to OLGA flip-chip packages with no sealant material between the IHS and substrate (see Figure 1). The lack of sealant on the IHS substrate results in sealant delamination between the heat spreader and substrate, leading to poor thermal performance. Adding spacers to the IHS lip and/or substrate interface ensures sealant is present to attach the substrate and IHS and maintain maximum thermal performance.

              Conventionally, the IHS is attached using the following methods:

·        Dispensing low-conductivity polymer thermal interface material (TIM) on the die

·        Dispensing sealant on the substrate

·        Placing the IHS and spring clip on top of the die

·        Curing the thermal interface material and sealant

Description

              The disclosed method is an integrated heat spreader (IHS) with a flat lip. Two or more 15-250 µm bumps, nodules, or spacers on the IHS lip or the substrate surface (see Figure 2) ensure that a minimum sealant bond line thickness (BLT) is maintained until the sealant is cured.

      Key elements include:

·        A highly conductive material, such as stamped or injection-molded copper, aluminum or AlSiC

·        A heat spreader designed to remove thermal energy generated from a circuit board component flip-...