Cu-Graphite Clad Material Bonding Against Cracks and Layer Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional heat radiating plates for electronic part mounting substrates face issues with thermal conductivity and layer separation or cracking under high shearing forces or thermal shock during press-working or thermal stress.
Innovation Solution
A clad material is produced by sintering a Cu-graphite layer with a Cu film and Mo-Cu layers, each with a metal film of Co, Ti, Pd, Pt, or Ni, and bonding them under pressure to enhance adhesion and prevent layer separation, while maintaining high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional composite materials (graphite laminated on metal) are used for heat radiating plates, then thermal conductivity is improved, but the materials are insufficient for high-power transistors requiring higher thermal conductivity
Solution Approach 1:
The invention uses a composite material structure where graphite powder is embedded in a Cu matrix to form a Cu-graphite composite layer. This composite structure combines the high thermal conductivity of copper with the high-temperature stability and thermal radiation properties of graphite, achieving thermal conductivity exceeding 300 W/mK that is suitable for high-power transistor applications.
2Temperature
If a cover layer is laminated on the core layer to improve thermal conductivity, then thermal performance is enhanced, but separation on the boundary surface may occur due to shearing force or thermal shock
Solution Approach 1:
The invention merges the cover layer and core layer materials at the boundary interface by embedding graphite powder particles in the Cu matrix that extend across the layer boundary. This creates a interlocked composite structure where the graphite particles physically connect both layers, preventing separation under shearing force or thermal shock while maintaining high thermal conductivity.
3Temperature
If Mo-Cu layers are used as cover layers to improve thermal conductivity, then thermal performance is enhanced, but cracks may form during press-working due to high shearing force
Solution Approach 1:
The invention changes the material parameters at the layer boundary by using a Cu matrix with embedded graphite particles instead of conventional Mo-Cu alloy layers. The Cu-graphite composite has different mechanical properties including lower brittleness and better ductility, allowing the material to withstand high shearing forces during press-working without forming cracks while maintaining thermal conductivity above 300 W/mK.
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 resulting clad material effectively prevents cracks and layer separation during press-working and thermal shock, achieving enhanced thermal conductivity suitable for high-performance heat radiating applications.
Implementation Method 1
preparing a Cu-graphite layer by sintering a graphite powder having a Cu film on the surface thereof
Implementation Method 2
heating the Cu-graphite layer and the Mo—Cu layers while a pressure is applied between the Cu-graphite layer and the Mo—Cu layers
Data Source
AI summary
There are provided a clad material and a method for producing the same, the clad material being capable of preventing cracks from being formed and preventing the separation of layers thereof from being caused, even if it is punched by press-working (even if a high shearing force is applied thereto by thermal shock. After each of Mo—Cu layers 10, which has a metal film 10a of a metal selected from the group consisting of Co, Ti, Pd, Pt and Ni on at least one side thereof is arranged on a corresponding one of both sides of a Cu-graphite layer 12, which is obtained by sintering a graphite powder having a Cu film on the surface thereof, so as to allow the metal film 10a to contact the Cu-graphite layer 12, the layers are heated while a pressure is applied between the Cu-graphite layer 12 and the Mo—Cu layers 10.