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Method for minimizing thermal interface material spread by using a heat spreader

IP.com Disclosure Number: IPCOM000006268D
Publication Date: 2001-Dec-19
Document File: 3 page(s) / 1K

Publishing Venue

The IP.com Prior Art Database

Abstract

During technology development, a new reliability failure mechanism was discovered in which the solder on the die-side capacitors (DSC) would bridge and short to the heat spreader during the attachment of the interposer. The root cause of the failure mechanism was identified as TIM spreading onto the DSCs. During a surface mount reflow the thermal interface material on the DSC expands, and the solder melts and is pushed on top of the capacitor (see Figure 2). Preventing solder doming during surface mount reflow requires the integrated heat spreader (IHS) module to significantly reduce the amount of TIM spread while ensuring complete die coverage and good reliability performance.

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Method for minimizing thermal interface material spread by using a heat spreader

Background

During technology development, a new reliability failure mechanism was discovered in which the solder on the die-side capacitors (DSC) would bridge and short to the heat spreader during the attachment of the interposer. The root cause of the failure mechanism was identified as TIM spreading onto the DSCs. During a surface mount reflow the thermal interface material on the DSC expands, and the solder melts and is pushed on top of the capacitor (see Figure 2).  Preventing solder doming during surface mount reflow requires the integrated heat spreader (IHS) module to significantly reduce the amount of TIM spread while ensuring complete die coverage and good reliability performance.

Description

Disclosed is a method for minimizing thermal interface material (TIM) spread by designing a heat spreader with modifications to the cavity shape.  Preventing the thermal interface material spread can improve reliability performance and prevent contact with other integrate circuit package components.                   The disclosed method addresses the problem of DSC solder doming caused by TIM spreading over the DSC solder pad.  This problem is conventionally addressed through tight process controls. The amount of TIM dispensed on the die is limited and wide exclusion zones on the package leave a 2-3 mm of area around the perimeter of the die for the thermal interface material to spread.

      Two techniques are disclosed to...