Graphite Heat Spreader Laminate for High Conductivity Yield
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Solution Overview
Problem
Thicker graphite-based heat spreader materials with higher heat dissipation requirements face inefficiencies in thermal conductivity due to lower crystallinity from increased precursor film thickness, and existing laminates suffer from yield loss issues like splices, wrinkles, and bubbles.
Innovation Solution
A method involving depositing an adhesive layer on graphite layers, forming alternating stacks, compressing with pressure between 7 to 20 MPa, and heating to remove solvent, resulting in a graphite laminate with enhanced thermal conductivity and reduced yield loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the precursor film is increased to dissipate greater quantity of heat, then the heat dissipation capability is improved, but the crystalline degree of the final graphitized film decreases leading to lower thermal conductivity
Solution Approach 1:
The precursor film is divided into multiple thinner layers (first precursor film and second precursor film) instead of using a single thick layer. Each layer is graphitized separately to maintain high crystalline degree, then bonded together to achieve the required total thickness for heat dissipation. This segmentation allows each layer to achieve optimal graphitization while the composite structure provides sufficient heat dissipation capability.
2Temperature
If two or more graphite-based layers are laminated using an adhesive film to increase heat spread, then the heat dissipation is improved, but splices, wrinkles and bubbles appear leading to yield loss
Solution Approach 1:
The adhesive composition parameters are changed by incorporating specific additives: silica particles (0.1-10 wt%) and wax (0.1-5 wt%). These parameter changes modify the adhesive's rheological properties and bonding characteristics, enabling it to fill gaps and accommodate thermal expansion differences between graphite layers without forming wrinkles or bubbles, thus preventing yield loss while maintaining heat spread capability.
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 the yield and thermal conductivity of graphite laminates by optimizing the adhesive layer thickness and compression pressure, minimizing defects and enhancing heat dissipation capabilities.
Implementation Method 1
depositing an adhesive (1) on a major surface of at least one graphite layer (2)
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
AI summary
A method for manufacturing a heat spreader including 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 the 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 the first stack of layers so as to form a second stack of layers, having a graphite layer as top and bottom layers iv. compressing the second stack of layer with a pressure from 7 to 20 MPa to form a graphite-based laminate, v. heating the graphite-based laminate such that the solvent of the adhesive is removed.