Direct-Cooling Fin Recess Structure for Lower Thermal Resistance
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Solution Overview
Problem
Current heat transfer technologies for semiconductor device modules are inadequate for high-power applications, as they often result in increased junction-to-fin thermal resistance due to adhesive layer cracks from thermal cycling and require excessive thermal adhesive material, leading to inefficiencies and cost issues.
Innovation Solution
A direct-cooling approach is implemented using a substrate with a metal layer and recesses, where cooling fins are thermally and mechanically coupled using a thermally conductive adhesive, reducing the need for a wide adhesive layer and enhancing mechanical integrity, thereby improving thermal conductivity and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a wide adhesive layer is used to couple the cooling fin with the metal layer, then the mechanical bonding is stronger, but the thermal resistance increases and thermal dissipation performance deteriorates
Solution Approach 1:
The patent transitions from a wide-area adhesive bonding approach to a focused point-contact approach by inserting the cooling fin into recesses. This dimensional change concentrates the thermal pathway while maintaining mechanical strength through precise geometric fitting and localized adhesive application at the fin-base interface.
Solution Approach 2:
The cooling fin structure implements local quality by concentrating thermal conduction pathways at specific locations (the fin bases inserted in recesses) rather than distributing adhesive uniformly across a wide area. This localized approach optimizes thermal contact where needed while minimizing thermal resistance.
2Reliability
If excessive thermal adhesive material is used, then the adhesive coverage is sufficient, but the material cost increases and thermal resistance increases
Solution Approach 1:
The patent extracts the adhesive from a wide-area application and concentrates it only at the critical fin-base interface within the recesses. This extraction eliminates unnecessary adhesive material while maintaining sufficient bonding and thermal contact at the essential interface.
Solution Approach 2:
Instead of applying adhesive uniformly across the entire metal layer surface (excessive action), the patent applies adhesive partially and selectively only at the recess locations where cooling fins are inserted, achieving sufficient bonding with minimal material.
3Strength
If adhesive layer cracks occur from thermal cycling, then the mechanical bonding fails, but the junction-to-fin thermal resistance increases
Solution Approach 1:
The recess structure serves as a cushioning mechanism that absorbs and distributes thermal expansion and contraction stresses during thermal cycling. By providing a geometric fit before stress accumulation occurs, the design prevents adhesive layer cracking that would otherwise lead to bonding failure and increased thermal resistance.
Solution Approach 2:
The solution employs a composite approach combining the cooling fin material, metal layer, recess geometry, and minimal adhesive material. This composite structure leverages the mechanical strength of the fitted geometry and the bonding capability of the adhesive to create a thermally and mechanically robust connection resistant to thermal cycling.
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 enhances thermal dissipation performance, reduces junction-to-fin thermal resistance, and allows for increased power consumption capabilities in high-power applications by improving mechanical integrity and reducing thermal adhesive usage by approximately 50%.
Implementation Method 1
a cooling fin thermally and mechanically coupled with the metal layer using a thermally conductive adhesive
Data Source
AI summary
In a general aspect, an apparatus includes a substrate and a metal layer disposed on a surface of the substrate. The apparatus also includes a first recess and a second recess formed in the metal layer, and a folded cooling fin. A first portion of the folded cooling fin is disposed within the first recess and coupled with the metal layer, and a second portion of the folded cooling fin is disposed in the second recess and coupled with the metal layer.