Thermal Interface Package with Non-Tacky Surface Layer
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Solution Overview
Problem
Thermal interfaces used in heat dissipation applications face challenges with tackiness at elevated temperatures, which complicates handling and assembly, and existing anti-blocking layers either require removal or inhibit conformability, affecting thermal performance.
Innovation Solution
A thermal interface package with a thermally conductive surface layer that remains non-tacky at or above solder reflow temperatures, combined with a phase-changing bulk layer for conformability, where the surface layer is deposited on a release substrate and applied in a thin, thermally transparent, and highly conductive form to ensure ease of handling and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phase-changing bulk layer is used to achieve conformability, then the thermal interface can conform to surface irregularities, but the surface becomes tacky at elevated temperatures making handling and assembly difficult
Solution Approach 1:
The thermal interface material is divided into two distinct layers: a bulk layer and a surface layer. The bulk layer contains the phase-changing material for conformability, while the surface layer provides a non-tacky handling surface. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
Different regions of the thermal interface material have different properties. The bulk layer has low modulus and phase-changing characteristics for conformability, while the surface layer has high modulus and remains solid at operating temperatures for easy handling. This local differentiation resolves the contradiction between conformability and ease of operation.
2Ease of operation
If an anti-blocking or release layer is formed on the thermal interface to prevent tackiness, then handling and assembly are improved, but the layer must be removed or it inhibits conformability
Solution Approach 1:
The thermal interface material is divided into two distinct layers: a bulk layer and a surface layer. The bulk layer contains the phase-changing material for conformability, while the surface layer provides a non-tacky handling surface. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The thermal interface material combines two different materials with complementary properties: a phase-changing bulk material for thermal conformability and a solid surface material for non-tacky handling. This composite structure allows both conformability and ease of operation to coexist without requiring removal of the surface layer.
3Ease of operation
If a release layer is permanently secured to the thermal interface to maintain non-tackiness, then handling is improved, but the overall conformability of the interface is significantly inhibited
Solution Approach 1:
Different regions of the thermal interface material have different properties. The bulk layer has low modulus and phase-changing characteristics for conformability, while the surface layer has high modulus and remains solid at operating temperatures for easy handling. This local differentiation resolves the contradiction between conformability and ease of operation.
Solution Approach 2:
The surface layer is designed as a thin film that provides the non-tacky handling surface while minimizing its impact on the overall conformability of the thermal interface. The thin film allows the underlying phase-changing bulk layer to still conform to surface irregularities effectively.
4Reliability
If conventional thermal interfaces are used, then heat transfer is enhanced, but the tacky surface at elevated temperatures causes contamination and assembly complications
Solution Approach 1:
The thermal interface material is divided into two distinct layers: a bulk layer and a surface layer. The bulk layer contains the phase-changing material for conformability, while the surface layer provides a non-tacky handling surface. This segmentation allows each layer to perform its specific function without compromising the other.
Solution Approach 2:
The thermal interface material combines two different materials with complementary properties: a phase-changing bulk material for thermal conformability and a solid surface material for non-tacky handling. This composite structure allows both conformability and ease of operation to coexist without requiring removal of the surface layer.
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
The solution enables efficient heat transfer by maintaining non-tackiness and conformability at elevated temperatures, simplifying assembly and handling while enhancing thermal conductivity and reducing contamination risks, allowing for secure attachment to electronic components before solder reflow.
Implementation Method 1
Conformability of the interface may be achieved through materials having low modulus values at room temperature, or may instead be achieved as a result of a 'phase changing' material which significantly softens at temperatures at or below the operating temperatures of the heat-generating devices
Implementation Method 2
a thermally conductive surface layer that remains non-tacky at or above solder reflow temperatures... efficient heat transfer by maintaining non-tackiness and conformability at elevated temperatures
Data Source
Figure 1~2
Figure 3A~3C
Figure 4
AI summary
A thermal interface member includes a bulk layer and a surface layer that is disposed on at least a portion of a surface of the bulk layer. The surface layer is highly thermally conductive, has a melting point exceeding a solder reflow temperature, and has a maximum cross-sectional thickness of less than about 10 microns.