Graphene Interposer with Negative Thermal Expansion
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Solution Overview
Problem
Current 3D micropackaging interposers face challenges with thermal conduction, mechanical rigidity, and thermal expansion mismatch between materials, leading to heat accumulation, structural weakness, and potential detachment of electrodes due to differing thermal expansion coefficients.
Innovation Solution
A graphene-based interposer with a negative coefficient of thermal expansion, combined with metal electrodes having a central conductive element and an insulating peripheral layer, which uses ultraviolet annealing to form conductive cores without significant temperature increase, allowing for flexible and cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a silicon interposer is used, then good thermal dispersion is achieved, but the high rigidity makes it difficult to use in flexible applications and the high Young's modulus of connection metals weakens the silicon layer
Solution Approach 1:
The patent changes the material parameter from silicon to graphene, which fundamentally alters the mechanical properties while maintaining thermal conductivity. Graphene's unique two-dimensional structure provides both excellent thermal dispersion and flexibility, resolving the contradiction between rigidity and adaptability.
Solution Approach 2:
The interposer uses a composite structure combining graphene layer with metal connection elements. The graphene provides thermal management and flexibility, while the metal electrodes provide electrical connectivity, creating a composite material system that achieves multiple functional requirements simultaneously.
2Volume of moving object
If the silicon volume decreases due to thinning for miniaturization, then the interposer size is reduced, but the metal volume of connections becomes proportionally greater causing significant heating
Solution Approach 1:
The patent changes the support layer material from silicon to graphene, which has superior thermal conductivity. This parameter change allows for more efficient heat dissipation even when the interposer is thinned, preventing the proportional heating issue that occurs with reduced silicon volume.
3Manufacturing precision
If through holes are made by etching and filling in silicon or glass, then metal electrodes are formed, but complex and expensive etching technologies are required to achieve good quality form factor
Solution Approach 1:
The patent replaces the complex mechanical etching and filling process with a simpler deposition technique. Metal electrodes are formed by directly depositing metal material through predefined openings in the graphene layer, eliminating the need for complex etching technologies while maintaining good hole quality form factor.
4Adaptability or versatility
If polychlorinated biphenyls are used for the interposer, then flexibility and simple manufacturing are achieved, but poor thermal conduction causes heat accumulation and thermal shock
Solution Approach 1:
The patent uses a composite material system where graphene provides the flexible support layer with excellent thermal conductivity, while metal electrodes provide electrical connections. This composite approach maintains the flexibility needed for applications like electronic skins while solving the heat accumulation problem through graphene's superior thermal management.
5Ease of manufacture
If polychlorinated biphenyls are used, then low-cost manufacturing is achieved, but high dielectric permittivity at high frequencies disturbs circuit operation
Solution Approach 1:
The patent changes the material from polychlorinated biphenyls to graphene, which has suitable dielectric properties for high-frequency circuit operation. Graphene's unique electronic structure provides low dielectric permittivity at high frequencies, eliminating the circuit disturbance issue while maintaining compatibility with low-cost manufacturing techniques.
6Stability of the object's composition
If materials with positive coefficient of thermal expansion are used, then the interposer matches the expansion of connected circuits, but large differences in expansion coefficients between layers and electrodes cause weakening under thermal variations
Solution Approach 1:
The patent changes the thermal expansion parameter of the support layer by using graphene, which has a negative coefficient of thermal expansion. This compensates for the positive expansion coefficients of metal electrodes and semiconductor circuits, reducing differential expansion and contraction effects under thermal variations, thereby maintaining assembly strength and preventing detachment.
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 graphene interposer effectively conducts heat, minimizes thermal expansion differences, and maintains electrode contact, enhancing the structural integrity and thermal management of microelectronic circuits while being flexible and low-cost to produce.
Implementation Method 1
good thermal conduction to dissipate heat
Implementation Method 2
uses ultraviolet annealing to form conductive cores without significant temperature increase
Implementation Method 3
graphene having a negative coefficient of thermal expansion
Implementation Method 4
a layer of material comprising a layer of graphene having a negative coefficient of thermal expansion
Data Source
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AI summary
An interface device comprises a layer of a material thoroughly crossed by metal electrodes intended to electrically connect two electronic circuits. According to the present invention, the layer of material comprises a graphene layer and the electrodes each comprise a central electrically-conductive element formed across the thickness of the graphene layer and an electrically-insulating peripheral layer, interposed between the central element and the graphene layer.