Nitride Semiconductor Transfer Bonding for Crack-Free Diamond Substrates
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Solution Overview
Problem
The formation of nitride semiconductor layers on diamond substrates is hindered by internal stress, leading to crack generation and deterioration of semiconductor element characteristics due to differences in material properties between the growth substrate and the nitride semiconductor layer.
Innovation Solution
A method involving the formation of nitride semiconductor layers on a growth substrate, followed by bonding with a support substrate using a resin adhesive layer, thinning the growth substrate, applying protective thin film layers, and transferring the nitride semiconductor layer to a diamond substrate while protecting the bonding portion to prevent crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nitride semiconductor layer is formed on a growth substrate by heteroepitaxial growth, then the nitride semiconductor layer can be manufactured using established techniques, but internal stress due to material property differences causes crack generation and deterioration of semiconductor element characteristics
Solution Approach 1:
The patent segments the manufacturing process into distinct phases: forming the nitride semiconductor layer on a growth substrate, bonding it to a support substrate, thinning the growth substrate, and finally transferring to a diamond substrate. This segmentation allows stress management at each stage, preventing crack generation while maintaining manufacturability.
Solution Approach 2:
The patent introduces a support substrate as an intermediary between the growth substrate and the final diamond substrate. This intermediary provides mechanical support during the thinning process and stress relief during transfer, preventing cracks in the nitride semiconductor layer while enabling the use of established heteroepitaxial growth techniques.
2Device complexity
If the growth substrate is thinned after bonding with support substrate using resin adhesive layer, then the bonding structure can be formed, but internal stress release causes crack generation in the nitride semiconductor layer
Solution Approach 1:
The patent applies preliminary protective actions by forming the resin adhesive layer and bonding structure before thinning the growth substrate. This preliminary bonding provides mechanical support that prevents crack generation during the subsequent thinning process, even though internal stress is released.
Solution Approach 2:
The patent changes the physical parameters of the growth substrate by controlling its thickness during the process. By maintaining appropriate thickness during bonding and then progressively thinning, the mechanical strength is sufficient to prevent cracks during stress release, while achieving the desired final thin structure.
3Temperature
If a nitride semiconductor layer is directly formed on a diamond substrate, then heat dissipation performance is improved, but the manufacturing technique is not yet established and requires complex bonding processes
Solution Approach 1:
Instead of directly forming the nitride semiconductor layer on the diamond substrate, the patent inverts the process by first forming it on a growth substrate using established heteroepitaxial techniques, then transferring it to the diamond substrate. This inversion enables heat dissipation benefits while using成熟 manufacturing techniques.
Solution Approach 2:
The patent creates a copy of the nitride semiconductor layer structure on a growth substrate using established techniques, then transfers this copy to the diamond substrate. This copying approach allows the use of proven manufacturing processes while achieving the heat dissipation performance of diamond substrates.
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
This method effectively suppresses crack occurrence in the nitride semiconductor layer, enabling high-quality nitride semiconductor elements with improved heat dissipation and reliability on diamond substrates.
Implementation Method 1
forming a resin adhesive layer between a first main surface of the growth substrate and a first main surface of a first support substrate, and bonding the epitaxial substrate to the first support substrate
Implementation Method 2
forming a first protective thin film layer from a second main surface of the thinned growth substrate to side surfaces of the resin adhesive layer; forming a second protective thin film layer from a second main surface of the first support substrate to the side surfaces of the resin adhesive layer
Implementation Method 3
bonding a second support substrate onto the nitride semiconductor layer... enabling high-quality nitride semiconductor elements with improved heat dissipation and reliability on diamond substrates
Data Source
AI summary
The present invention relates to a method for manufacturing a semiconductor substrate, including: (a) preparing an epitaxial substrate having a nitride semiconductor layer formed on a first main surface of a growth substrate and preparing a first support substrate, forming a resin adhesive layer between the first main surface of the growth substrate and a first main surface of the first support substrate, and bonding the epitaxial substrate to the first support substrate; (b) thinning a second main surface of the growth substrate; (c) forming a first protective thin film layer on the thinned growth substrate; (d) forming a second protective thin film layer on the first support substrate; (e) removing the thinned growth substrate; (f) bonding a second support substrate onto the nitride semiconductor layer; and (g) removing the first support substrate and the resin adhesive layer.