AlN-Al2O3 Substrate Bonding Interface for Heat Dissipation
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Solution Overview
Problem
Conventional bonding dielectric materials in semiconductor devices have low thermal conductivity, leading to localized heating and temperature build-up, which compromises device performance and reliability, while materials like aluminum nitride and diamond face challenges in achieving smooth surfaces for effective direct substrate bonding.
Innovation Solution
Incorporating aluminum nitride layers with an aluminum oxide bonding layer to mediate bonding, using techniques like ALD and planarization to achieve smooth surfaces, enabling direct bonding with improved thermal conductivity and bond strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional bonding dielectric materials are used, then bonding process is simple, but thermal conductivity is low leading to localized heating and temperature build-up
Solution Approach 1:
The patent uses a composite bonding structure consisting of aluminum oxide bonding layers combined with aluminum nitride thermally conductive layers. This composite approach enables the bonding interface to achieve high thermal conductivity (greater than 10 W/mK, preferably greater than 50 W/mK) while maintaining bonding capability, thereby resolving the contradiction between simple bonding processes and thermal management requirements.
2Temperature
If aluminum nitride layers are used to improve thermal conductivity, then thermal conductance increases, but surface smoothness for effective direct substrate bonding becomes difficult to achieve
Solution Approach 1:
The patent introduces aluminum oxide layers as intermediary bonding layers between the aluminum nitride thermally conductive layers and the substrate surfaces. The aluminum oxide layers serve as a mediator that provides the necessary surface smoothness and bonding characteristics, while the aluminum nitride layers provide thermal conductivity. This intermediary approach allows the system to achieve both high thermal conductance and effective direct substrate bonding.
Solution Approach 2:
The bonding structure combines aluminum oxide and aluminum nitride layers in a composite configuration where each material performs its specialized function. The aluminum oxide provides bonding compatibility and surface smoothness, while aluminum nitride provides thermal conductivity, thereby resolving the contradiction between thermal performance and surface quality.
3Reliability
If direct bonding is performed without thermally conductive layers, then bonding process is simpler, but heat dissipation capability is insufficient
Solution Approach 1:
The aluminum nitride layers serve multiple functions: they act as thermally conductive pathways for heat dissipation, maintain structural integrity at the bonding interface, and work in conjunction with aluminum oxide layers to enable direct bonding. This multi-functionality improves heat dissipation capability while keeping the manufacturing process relatively straightforward, as the layers are deposited using standard semiconductor fabrication techniques.
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 enhances thermal conductance and bond strength, allowing for better heat dissipation and reliable wafer-to-wafer bonding, reducing voids and improving device performance.
Implementation Method 1
direct substrate bonding processes
Implementation Method 2
activating the aluminum oxide bonding layer using a nitrogen plasma
Implementation Method 3
annealing the bonded substrate structure at a temperature less than 400° C.
Data Source
AI summary
A bonded substrate structure includes a first substrate; a second substrate; and a bonding region bonding the first substrate to the second substrate. The bonding region includes an aluminum oxide bonding layer directly contacting an aluminum nitride layer, and a bonding interface between the aluminum oxide bonding layer and a bonding surface of the first substrate or the second substrate.