Semiconductor Module Pressing Member for Sintered Metal Peeling
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Solution Overview
Problem
Conventional power modules using sintered metal bonding materials face issues with compressive and tensile stress due to thermal expansion, leading to peeling at the interface between the semiconductor element and the sintered metal layer, which is not adequately addressed by existing solutions like elastically deformable spring members sealed with mold resin.
Innovation Solution
A semiconductor module design featuring a first cooling member, a semiconductor element with a first bonding layer, a pressing member with a second bonding layer, and a sealing configuration that includes a tray-shaped block member, elastic members, and a sealing material to allow for thickness change accommodation, reducing strain and preventing peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sintered metal bonding material is used to bond semiconductor element and cooling member, then bonding strength and high temperature resistance are improved, but peeling occurs at the interface due to thermal stress
Solution Approach 1:
The patent introduces a pressing member with elastic elements (spring members or elastic resin) that preemptively accommodate thermal expansion and contraction of the sintered metal bonding material. This cushioning mechanism prevents tensile stress from developing at the interface between the semiconductor element and bonding material during cooling cycles, thereby preventing peeling while maintaining strong bonding.
Solution Approach 2:
The patent changes the mechanical parameters of the bonding structure by introducing elastic elements with specific elastic moduli and spring constants. These parameter changes allow the bonding structure to dynamically adapt to thermal stress, maintaining interface integrity during temperature cycling while preserving bonding strength.
2Reliability
If elastically deformable spring members are provided to follow thickness change of sintered metal layer, then peeling is prevented, but the structure becomes more complex and the spring members may not sufficiently follow thickness change when sealed with highly elastic mold resin
Solution Approach 1:
The patent employs elastic elements that can be integrated into the existing module structure without adding significant complexity. These elastic elements act as flexible components that conform to the thermal deformation of the sintered metal layer, providing the necessary compliance to prevent peeling while maintaining a relatively simple overall structure.
Solution Approach 2:
The pressing member with elastic elements serves as an intermediary between the sintered metal bonding material and the semiconductor element. This intermediary component absorbs thermal stress and allows the bonding interface to follow thickness changes without direct mechanical constraint, thereby preventing peeling while maintaining structural simplicity.
3Strength
If the periphery of the module is sealed with mold resin, then structural integrity is improved, but deformation in thickness direction is constrained causing tensile stress at the interface
Solution Approach 1:
The pressing member with elastic elements provides preemptive cushioning that compensates for the constraint imposed by the mold resin sealing. By accommodating thermal deformation before it translates into interface stress, the elastic elements prevent peeling while allowing the mold resin to maintain its structural integrity and sealing function.
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 design effectively suppresses peeling at the interface between the semiconductor element and the bonding layer by allowing the sintered metal layer to expand and contract freely, reducing strain and preventing cracking, while maintaining bonding strength.
Implementation Method 1
an elastic member and second sealing material that are provided in a region between the first block member and the second block member
Implementation Method 2
members around the semiconductor element are thermally expanded due to the heat generated by the semiconductor element
Implementation Method 3
a bonding layer made of sintered metal has a porous structure including pores therein
Implementation Method 4
compressive stress is generated. Due to the compressive stress and the heat at this time, the pores inside a sintered metal layer are collapsed and sintering proceeds
Data Source
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AI summary
This semiconductor module is achieved by having: a first cooling member; a semiconductor element that is provided above the first cooling member by having a first bonding layer therebetween; a pressing member that is provided above the semiconductor element by having a second bonding layer therebetween; and a first sealing material, which is provided above the first cooling member, and which seals a region positioned in the side surface direction of the semiconductor element and the pressing member. The pressing member comprises: a first block member; a second block member that is provided above the first block member; and a spring member and a second sealing material, which are provided in a region between the first block member and the second block member.