Thermal Interface Unit With Flat Spring for Multi-Chip Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal units struggle to establish simultaneous good mechanical and thermal contacts with multiple die in multi-chip electronic packages due to varying die heights and warping, leading to inadequate cooling and potential overheating during testing.
Innovation Solution
A thermal interface unit with a pedestal and a flat spring mechanism that adapts to variable die heights, providing a mechanical assembly with heat spreader contact surfaces and a fluid channel for enhanced cooling, allowing for efficient heat removal and minimizing the need for large thermal unit profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal units with rigid pedestals are used, then the thermal unit structure is simple, but inadequate contact coverage leads to poor thermal cooling and control
Solution Approach 1:
The patent changes the physical state of the contact interface by introducing a compliant layer that can deform elastically under load. This allows the rigid pedestal structure to adapt to varying die heights and warping, maintaining adequate contact coverage across all die surfaces while preserving the overall simplicity of the thermal unit structure.
Solution Approach 2:
The patent employs a compliant layer (flexible element) between the rigid pedestal and the die surfaces. This thin flexible film deforms to conform to the actual die topography, ensuring continuous thermal contact across all die surfaces despite height variations and warping, thereby improving thermal cooling effectiveness without requiring complex adjustable mechanisms.
2Manufacturing precision
If rigid pedestal structures are used, then manufacturing is simple, but height offsets create areas of poor or non-contact
Solution Approach 1:
The patent introduces a compliant layer with specific elastic properties that allows the pedestal structure to adapt to height variations. This layer can be manufactured using standard semiconductor fabrication processes, maintaining ease of manufacture while significantly improving contact coverage uniformity across all die surfaces.
Solution Approach 2:
The compliant layer serves as an intermediary element between the rigid pedestal and the die surfaces. It mediates the mechanical interface, absorbing height offsets and warping variations through elastic deformation, thereby ensuring uniform contact coverage without requiring complex precision manufacturing of the pedestal itself.
3Reliability
If large thermal unit profiles are used to eliminate height offset, then contact coverage is improved, but the thermal unit size increases
Solution Approach 1:
The patent uses a thin compliant layer that can deform to accommodate height variations without requiring a large thermal unit profile. This flexible film approach maintains adequate contact coverage across all die surfaces while keeping the thermal unit compact and suitable for standard testing equipment.
Solution Approach 2:
The patent changes the mechanical compliance parameter of the interface by introducing the elastic layer. This allows the thermal unit to adapt to height variations through material deformation rather than increasing structural dimensions, thereby maintaining good contact coverage with a compact thermal unit profile.
4Reliability
If test power is reduced to prevent die damage, then die reliability is maintained, but test time increases
Solution Approach 1:
The patent implements a compliant layer that beforehand cushions and distributes the thermal and mechanical loads across all die surfaces. This pre-protection mechanism ensures uniform heat removal and stress distribution during normal testing, allowing tests to proceed at full power without risking die damage, thereby maintaining both die integrity and short test times.
Solution Approach 2:
The compliant layer acts as a sacrificial element that absorbs mechanical stresses and thermal variations, protecting the expensive die from damage. By using this lower-cost compliant interface material, the system can withstand higher test powers without risking die failure, thus reducing test time while maintaining die integrity.
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 ensures effective thermal cooling and control across all die surfaces, reducing the risk of overheating and allowing for shorter test times without damaging the die, while maintaining a low profile and adaptable design.
Implementation Method 1
a flat spring to enable the first contact surface to adapt to a variable height of a first die
Implementation Method 2
heat spreader contact surfaces and a fluid channel for enhanced cooling
Implementation Method 3
a fluid channel for enhanced cooling, allowing for efficient heat removal
Data Source
AI summary
A thermal interface unit includes a pedestal, a first contact surface below the pedestal to interface with a first die and a flat spring to enable the first contact surface to adapt to a variable height of a first die of a multi-chip package (MCP).