Semiconductor Die Recess Sidewalls Contain Thermal Interface Material
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal interface materials (TIMs) in semiconductor devices often experience pump-out and void formation when a heat spreader is mounted, leading to reduced thermal conductivity and increased risk of overheating, which can decrease the reliability and lifespan of semiconductor packages.
Innovation Solution
A method involving the formation of a recess in the back surface of a semiconductor die with sidewalls to contain the TIM, ensuring uniform coverage and preventing pump-out, while a heat spreader with a down leg portion is thermally connected to the substrate to maintain efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat spreader is mounted directly over a thermal interface material (TIM) on a semiconductor die, then heat dissipation capability is improved, but the TIM experiences pump-out and void formation leading to reduced thermal conductivity
Solution Approach 1:
The invention segments the heat spreader structure into two distinct parts: a first heat spreader portion that contacts the TIM and a second heat spreader portion that is elevated above the TIM. This segmentation prevents the pump-out effect while maintaining thermal contact through the thermal conductor, resolving the contradiction between heat dissipation and TIM integrity.
Solution Approach 2:
A thermal conductor is introduced as an intermediary element between the first heat spreader portion and the second heat spreader portion. This intermediary maintains the thermal pathway while allowing the heat spreader to be mounted without directly compressing the TIM, thus preserving TIM thermal conductivity while enabling effective heat dissipation.
2Strength
If mounting pressure is applied to secure the heat spreader, then mechanical attachment strength is improved, but TIM is forced out from under the heat spreader creating voids
Solution Approach 1:
The heat spreader is divided into a first portion that applies minimal pressure to the TIM and a second portion that receives the mounting pressure. This segmentation allows mechanical attachment strength to be achieved without transmitting excessive compressive force to the TIM, preventing pump-out while maintaining secure attachment.
Solution Approach 2:
The invention introduces a vertical dimension to the heat spreader structure with the second heat spreader portion extending upward from the first portion. This dimensional change allows mounting pressure to be applied to the upper surface of the second portion without directly compressing the TIM, maintaining both attachment strength and TIM coverage uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maintains the design thickness of the TIM, preventing void formation and enhancing thermal conductivity, thereby improving heat dissipation and reducing the risk of overheating and package failure.
Implementation Method 1
A thermal interface material is deposited in the recess. A heat spreader is mounted in the recess with a down leg portion of the heat spreader thermally connected to the substrate.
Implementation Method 2
mounting a heat spreader in the recess with a down leg portion of the heat spreader thermally connected to the substrate
Data Source
AI summary
A semiconductor device has a semiconductor die mounted to a substrate. A recess is formed in a back surface of the semiconductor die to an edge of the semiconductor die with sidewalls on at least two sides of the semiconductor die. The sidewalls are formed by removing a portion of the back surface of the die, or by forming a barrier layer on at least two sides of the die. A channel can be formed in the back surface of the semiconductor die to contain the TIM. A TIM is formed in the recess. A heat spreader is mounted in the recess over the TIM with a down leg portion of the heat spreader thermally connected to the substrate. The sidewalls contain the TIM to maintain uniform coverage of the TIM between the heat spreader and back surface of the semiconductor die.