Copper-Diamond Heat Spreader with Gradient CTE via Electron Beam
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Solution Overview
Problem
Conventional thermal processing methods for producing copper-diamond heat spreaders are inefficient and lack control over the coefficient of thermal expansion (CTE), making it difficult to achieve materials compatibility and effective thermal management for high-power devices.
Innovation Solution
The use of electron beam processing to create a copper-diamond composite with a gradient in diamond concentration, allowing for precise control over the CTE and thermal conductivity, achieved by scanning an electron beam across the surface to melt and sinter the material locally, thereby preserving the spatial variation in diamond concentration and eliminating the need for a thermal interface layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional thermal processing methods are used to produce copper-diamond heat spreaders, then the processing can be performed with standard equipment, but the energy efficiency is low and control over the coefficient of thermal expansion is poor
Solution Approach 1:
The electron beam processing method applies localized heating to specific regions of the copper-diamond composite, allowing independent control of thermal properties at different locations. This enables precise control of the coefficient of thermal expansion gradient through the material thickness while maintaining high energy efficiency by heating only the required volume rather than the entire workpiece
Solution Approach 2:
The invention utilizes the ability to independently vary electron beam parameters (current, voltage, scan speed, pulse duration) to control the heating profile and achieve desired thermal property gradients. By changing these parameters dynamically during processing, the system can precisely control the coefficient of thermal expansion while maintaining energy efficiency
2Manufacturing precision
If conventional thermal processing is used, then equipment simplicity is maintained, but manufacturing precision of CTE gradient is insufficient
Solution Approach 1:
The electron beam system creates a controlled gradient in diamond concentration by locally heating and sintering diamond particles into the copper matrix at different concentrations through the thickness. This local quality variation precisely controls the CTE gradient, with higher diamond concentration near the heat source interface (lower CTE) and lower concentration away from it (higher CTE), achieving manufacturing precision of CTE gradient control
Solution Approach 2:
The invention replaces conventional mechanical or furnace-based thermal processing with electron beam processing. This substitution enables precise control of heating parameters through electrical fields, allowing accurate control of the CTE gradient with better manufacturing precision compared to mechanical mixing or conventional furnace methods
3Adaptability or versatility
If diamond concentration is uniformly distributed, then material homogeneity is achieved, but CTE matching at both interfaces cannot be accomplished
Solution Approach 1:
The electron beam processing creates a non-uniform diamond concentration distribution with higher concentration near the heat source interface and lower concentration at the opposite interface. This local variation in composition enables CTE matching at both interfaces - the high diamond concentration region provides low CTE near the heat source, while the lower concentration region provides higher CTE away from it, achieving interface compatibility without requiring uniform composition
Solution Approach 2:
The invention introduces asymmetry in the diamond concentration distribution through the thickness of the heat spreader. Rather than uniform distribution, the concentration varies systematically, creating an asymmetric composition profile that enables different thermal expansion behaviors at opposite interfaces, thus achieving CTE matching at both the heat source interface and the heat sink interface
4Reliability
If a thermal interface layer is added to improve heat transfer, then thermal management is enhanced, but additional material layers increase thermal stress at interfaces
Solution Approach 1:
The invention extracts and eliminates the thermal interface layer from the system by directly bonding the copper-diamond composite to both the heat source and heat sink interfaces. The gradient in diamond concentration within the copper matrix itself provides the necessary thermal management functionality, making the separate interface layer redundant. This removal eliminates the additional thermal stress that would arise from multiple material interfaces while maintaining effective thermal management
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 enables the production of heat spreaders with tunable CTE and enhanced thermal conductivity, improving heat transfer and system reliability by minimizing thermal stress at interfaces, while reducing energy losses and processing time.
Implementation Method 1
the near-relativistic electrons are directed to the workpiece and bombard the surface/subsurface thereof, thereby generating both heat and radiation from scattering events
Implementation Method 2
the rate of thermal energy delivered to the surface/subsurface can be greater that the rate of heat conduction within the material
Implementation Method 3
generating both heat and radiation from scattering events
Implementation Method 4
several apertures and magnetic lenses to collimate, focus and steer the beam
Data Source
AI summary
A body comprising at least two components having one or more different properties and a method of producing the same are disclosed. One of the body components is in the form of particles with optional adhesive interlayers. A second of the components has a surface locally melted in a predetermined pattern and only to a predetermined depth by scanning an electron beam there across to incorporate the particles and form a metal composite film. Thereby, a predetermined volumetric concentration of the incorporated particles varies continuously from the locally melted surface so as to provide two surfaces in the body having different coefficients of thermal expansion.