Cross-Stacked Graphite Substrate for Semiconductor Heat Spreading
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Solution Overview
Problem
Conventional semiconductor devices face limitations in thermal dissipation due to the high thermal resistance of metal patterns, leading to localized heat retention near semiconductor elements.
Innovation Solution
A semiconductor device with a conductive substrate composed of graphite layers made of stacked graphenes, where the graphenes in the first base layer are stacked perpendicular to the thickness direction and those in the second base layer are stacked intersecting the first direction, enhancing thermal conductivity and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pattern of metal foil is used as the conductive substrate, then electrical conductivity is achieved, but thermal dissipation is insufficient due to high thermal resistance perpendicular to the thickness direction
Solution Approach 1:
The patent uses a composite substrate combining metal foil and graphite layers. The metal foil provides electrical conductivity while the graphite layers provide high thermal conductivity in the thickness direction, creating a composite material that simultaneously achieves both electrical and thermal performance requirements.
Solution Approach 2:
The patent introduces graphite layers with a specific crystalline orientation where the c-axis (stacking direction of graphenes) is aligned perpendicular to the substrate surface. This dimensional arrangement exploits the anisotropic thermal conductivity of graphite, achieving high thermal conductivity in the thickness direction (perpendicular to metal foil planes) where conventional metal patterns fail.
2Reliability
If conventional metal patterns are used, then electrical connection is established, but heat accumulates locally near semiconductor elements due to limited heat conduction
Solution Approach 1:
The composite structure of metal foil and graphite layers maintains the electrical connection function of the metal pattern while adding thermal management capabilities through the graphite's high thermal conductivity, preventing local heat accumulation.
Solution Approach 2:
The conductive substrate is designed to perform multiple functions simultaneously: the metal foil layer provides electrical conductivity and connection, while the graphite layers provide thermal conduction. This multi-functional design eliminates the need for separate thermal management components.
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 configuration effectively distributes heat generated by semiconductor elements in three-dimensional directions, improving thermal dissipation and reducing localized heat retention.
Implementation Method 1
The conductive substrate includes a first base layer and a second base layer each of which is made of graphite composed of stacked graphenes... effectively distributes heat generated by semiconductor elements in three-dimensional directions, improving thermal dissipation
Data Source
AI summary
Semiconductor device (A10) includes conductive substrate (20) and semiconductor element (40). The conductive substrate (20) has obverse surface (20A) facing in thickness direction (z) and reverse surface (20B) facing opposite from the obverse surface (20A). The semiconductor element (40) is electrically bonded to the obverse surface (20A). The conductive substrate (20) includes first base layer (211), second base layer (212) and metal layer (22). The first base layer (211) and second base layer (212) are made of graphite composed of stacked graphenes. The metal layer (22) is between the first base layer (211) and the second base layer (212). The graphenes of the first base layer (211) are stacked in first stacking direction perpendicular to the thickness direction (z). The graphenes of the second base layer (212) are stacked in second stacking direction perpendicular to the thickness direction (z) and crossing the first stacking direction.