Extended TIM Preform Controls Bleed-Out Direction
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Solution Overview
Problem
The uncontrolled bleed-out of thermal interface materials (TIMs) between a die and an integrated heat spreader in electronic devices leads to device failures, as it can touch die-side components, causing shorts and increasing failure rates, especially as the distance between the die and these components decreases.
Innovation Solution
An extended preform of thermal interface material is used, with an extension beyond the die footprint to control the direction and size of the bleed-out, leveraging a pressure gradient induced by differential curvatures during curing, eliminating the need for an inner sealant bead and reducing manufacturing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal interface material is applied between die and heat spreader to improve thermal transfer, then thermal transfer efficiency is improved, but TIM bleed out touches die-side components causing device failures
Solution Approach 1:
The patent applies preliminary action by pre-defining the TIM preform with an extended footprint that anticipates and controls the bleed-out direction before curing occurs. The extended preform is strategically designed to guide TIM flow away from die-side components during the curing process, preventing shorts while maintaining thermal efficiency.
Solution Approach 2:
The extended preform acts as an intermediary element between the die and heat spreader, controlling the TIM distribution and preventing direct contact between bleed-out TIM and die-side components. This intermediary structure manages the thermal interface while blocking the harmful path of TIM migration.
2Reliability
If inner sealant bead is used to control TIM bleed out, then device reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the inner sealant bead from the manufacturing process by incorporating the bleed-out control function directly into the TIM preform structure. The extended preform design inherently guides TIM flow without requiring separate sealant materials or additional masking steps, simplifying the manufacturing process while maintaining reliability.
Solution Approach 2:
The extended TIM preform serves multiple functions simultaneously: it provides thermal interface material, controls bleed-out direction, and eliminates the need for separate sealant beads. This multi-functional design reduces manufacturing complexity by consolidating several functions into a single component.
3Area of stationary object
If die-side components are placed closer to die to reduce package size, then package compactness is improved, but TIM bleed out more easily touches components causing failures
Solution Approach 1:
The patent applies local quality by creating non-uniform TIM distribution through the extended preform design. The preform has different dimensions in different directions, with extensions strategically placed to control TIM flow locally away from die-side components while maintaining adequate coverage over the die area, enabling compact packaging without sacrificing reliability.
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 effectively directs and sizes the TIM bleed-out, preventing device failures by ensuring controlled TIM distribution, increasing manufacturing throughput by up to 40% and reducing the need for additional equipment and processing steps, while maintaining device reliability and performance.
Implementation Method 1
leveraging a pressure gradient induced by differential curvatures during curing
Data Source
AI summary
An extended preform of a thermal interface material (TIM) is formed between a heat spreader and a die on a substrate. The preform has an extension beyond a footprint of the die. The preform is cured. A bleed out of the TIM is controlled by the extension upon curing of the preform.