Semiconductor Device Metal Ring Gap Filling
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Solution Overview
Problem
High thermal resistance and reduced heat transfer in power semiconductor modules using AlSiC base plates lead to depletion of thermal paste due to gap formation between the base plate and heat sink, causing inefficiency in heat dissipation and potential chip failure.
Innovation Solution
A semiconductor device with a MgSiC base plate and a metal ring formed from materials like copper or aluminum, which is deformed to fill surface roughness gaps between the heat sink and base plate, ensuring improved adhesiveness and preventing thermal paste depletion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hardening process is applied to the heat sink surface, then the heat sink becomes resistant to deformation, but gaps form between the heat sink and base plate due to surface roughness
Solution Approach 1:
The patent introduces a soft metal layer (200 μm thick aluminum or copper) on the base plate surface that acts as a flexible deformation zone. This thin film layer deforms under pressing force to fill gaps caused by heat sink surface roughness, while the underlying hard base plate maintains structural strength and deformation resistance.
Solution Approach 2:
The base plate is constructed as a composite structure with a hard substrate (AlSiC or copper alloy) providing thermal conductivity and structural strength, combined with a soft metal surface layer (aluminum or copper) that provides deformation capability. This composite structure resolves the contradiction between hardness for deformation resistance and softness for gap filling.
2Stability of the object's composition
If AlSiC composite material is used in the base plate, then thermal expansion deformation is reduced, but the base plate becomes harder and less able to fill gaps with the heat sink
Solution Approach 1:
A soft metal layer (200 μm thick aluminum or copper) is applied on the AlSiC base plate surface. This thin film provides the necessary flexibility and softness to deform and fill gaps with the heat sink surface, while the AlSiC substrate maintains thermal expansion stability.
Solution Approach 2:
The base plate uses a composite structure combining AlSiC (providing thermal expansion stability) with a soft metal surface layer (aluminum or copper, providing gap filling capability). This composite approach allows both contradictory properties to coexist in different layers of the same component.
3Reliability
If the metal ring thickness is increased, then the filling effect on surface roughness gaps is improved, but the deformation capability of the metal ring is reduced
Solution Approach 1:
The metal ring thickness is optimized to a specific range (0.05-0.5 mm, preferably 0.1-0.3 mm) that balances deformation capability and gap filling effect. This parameter optimization ensures the ring is thin enough to deform effectively but thick enough to fill surface roughness gaps, resolving the contradiction between these two requirements.
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
Enhances thermal conductivity and prevents thermal paste depletion, thereby improving heat dissipation and reliability of power semiconductor modules.
Implementation Method 1
the soft Al metal layer 1010 is deformed by a pressing force of the base plate 103
Implementation Method 2
adhesiveness of the heat sink 1011 and the power semiconductor module improves
Implementation Method 3
a heat sink mounted to the base plate, via a thermal paste and a metal ring
Data Source
AI summary
A semiconductor device includes a base plate to which a stacked substrate is bonded, the stacked substrate being mounted on a semiconductor chip. The semiconductor device further includes a heat sink mounted to the base plate, via thermal paste and a metal ring. A center hole of the metal ring is provided to face the semiconductor chip and the thermal paste fills the center hole. Further, the metal ring is formed using a material having about a same hardness as the heat sink, or a material having a lower hardness than the hardness of the heat sink.