Graphite Heat Spreader Laminate for High Conductivity and Yield
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Solution Overview
Problem
Thicker graphite-based heat spreader materials face reduced thermal conductivity due to lower crystallinity, and laminating layers with adhesive films leads to defects like splices and bubbles, resulting in yield loss.
Innovation Solution
A manufacturing method involving the deposition of an adhesive layer on graphite layers, forming alternating stacks, followed by compression and solvent removal, to create a graphite laminate with enhanced thermal conductivity and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the precursor film is increased to dissipate greater heat, then the heat dissipation capacity is improved, but the crystalline degree of the final graphitized film decreases leading to lower thermal conductivity
Solution Approach 1:
The patent divides the thick graphite precursor film into multiple thinner layers (each 10-200 μm thick). Each layer is independently graphitized to achieve high crystalline degree, then laminated together to achieve the required total thickness for heat dissipation. This segmentation allows each layer to maintain high thermal conductivity while the composite structure provides sufficient heat dissipation capacity.
Solution Approach 2:
The patent creates a composite laminate structure by bonding multiple graphite layers together with an adhesive layer. The composite maintains high thermal conductivity through the graphitic structure while achieving the necessary thickness for heat dissipation. The adhesive layer (0.5-10 μm) bonds the graphite layers without significantly compromising thermal performance.
2Quantity of substance
If two or more graphite-based layers are laminated using an adhesive film to increase heat spread, then the heat dissipation capacity is improved, but defects such as splices, wrinkles and bubbles appear leading to yield loss
Solution Approach 1:
The patent optimizes the adhesive layer thickness to a specific range (0.5-10 μm) to minimize defects. The adhesive composition and application parameters are controlled to ensure uniform bonding without excess adhesive that could cause bubbles or wrinkles. The bonding process parameters (pressure, temperature, time) are optimized to achieve defect-free lamination.
Solution Approach 2:
The adhesive layer serves as an intermediary between graphite layers, providing controlled bonding that eliminates the need for mechanical splicing. The adhesive creates a seamless bond that prevents wrinkles and bubbles, maintaining manufacturing precision while enabling the laminate structure for enhanced heat spread.
3Quantity of substance
If thicker graphite-based heat spreader material is used to dissipate greater heat, then the heat dissipation capacity is improved, but the crystalline degree decreases resulting in lower thermal conductivity
Solution Approach 1:
The patent segments the thick graphite structure into multiple thin layers (10-200 μm each), where each layer can be fully graphitized to achieve high crystalline degree and thermal conductivity. The segmented layers are then stacked to achieve the required total thickness for heat dissipation, combining the benefits of high crystallinity in each layer with sufficient overall thickness.
Solution Approach 2:
The patent creates a composite laminate of multiple graphite layers bonded with adhesive, where each layer maintains high thermal conductivity through proper graphitization. The composite structure achieves the necessary thickness for heat dissipation while preserving high thermal conductivity through the graphitic structure of each individual layer.
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 method improves yield by enhancing thermal conductivity and minimizing defects in graphite laminates, making them suitable for high heat dissipation applications.
Implementation Method 1
depositing an adhesive (1) on a major surface of at least one graphite layer (2), to obtain at least one graphite layer coated by an adhesive layer (10)
Implementation Method 2
compressing said second stack of layer (4) with a pressure from 7 to 20 MPa to form a graphite-based laminate (5)
Implementation Method 3
heating said graphite-based laminate (5) such that the solvent of the adhesive is removed
Data Source
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AI summary
The invention relates to a method for manufacturing a heat spreader comprising the steps of i. depositing an adhesive on a major surface of at least one graphite layer, to obtain at least one graphite layer coated by an adhesive layer, wherein ii. positioning said at least one graphite layer coated by an adhesive layer on top of each other so as to form a first stack of layers alternating graphite layer and adhesive layer iii. positioning a graphite layer having a thickness from 10 to 200 μm, on said first stack of layers so as to form a second stack of layers, having a graphite layer as top and bottom layers iv. compressing said second stack of layer with a pressure from 7 to 20 MPa to form a graphite-based laminate, v. heating said graphite-based laminate such that the solvent of the adhesive is removed.