Composite Substrate Groove Bonding for Faster Substrate Removal
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Solution Overview
Problem
The existing method for manufacturing composite substrates for GaN transistors using a diamond base material is inefficient due to the long time required to dissolve the inorganic adhesive, which can lead to unintended flaking of the supporting diamond substrate during transistor fabrication processes.
Innovation Solution
A composite substrate is formed with a first bonding material on one substrate and a second bonding material on another substrate, with at least one groove on the first substrate. The bonding materials are bonded together except in the groove area, and the composite substrate is immersed in a dissolving solution to accelerate the separation of the substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the composite substrate is immersed in a chemical solution to dissolve the inorganic adhesive, then the supporting diamond substrate can be removed from the polycrystalline diamond substrate, but it takes relatively a long time to dissolve the adhesive
Solution Approach 1:
The bonding material layer is divided into multiple regions: a first region with the bonding material and a second region without the bonding material. This segmentation allows the chemical solution to access and dissolve the bonding material more efficiently through the second region, significantly reducing the dissolution time while maintaining the structural integrity needed for stable transistor fabrication processes.
2Ease of manufacture
If a chemical solution is used during transistor fabrication processes, then fabrication can proceed, but the chemical solution may infiltrate the inorganic adhesive and cause the supporting diamond substrate to flake off inadvertently
Solution Approach 1:
A protective film is formed in advance on the polycrystalline diamond substrate before the bonding material is applied. This protective film acts as a barrier that prevents chemical solutions used during transistor fabrication from infiltrating the inorganic adhesive, thereby preventing unintended flaking of the supporting diamond substrate while allowing normal fabrication processes to proceed.
Solution Approach 2:
The protective film serves as an intermediary layer between the chemical solutions and the inorganic adhesive. It allows the chemical solutions to pass through or be contained without reaching the adhesive, thus mediating the interaction between the fabrication chemicals and the bonding structure to prevent substrate flaking.
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 accelerated dissolution of the bonding materials shortens the time required to remove the supporting diamond substrate, and the groove design prevents unintended dissolution and flaking of the composite substrate, ensuring stable transistor fabrication processes.
Implementation Method 1
immersing, in a dissolving solution for dissolving the first bonding material and the second bonding material, the composite substrate with the first bonding material and the second bonding material being bonded together
Data Source
AI summary
Removal of substrates in a composite substrate is facilitated, and flaking of the composite substrate in an unintended process is prevented. A method for manufacturing a composite substrate includes: forming a first bonding material in a first surface of a first substrate; forming, in the first surface, at least one groove located more inward than a periphery in a plan view of the first substrate; forming the first bonding material along an inner wall of the at least one groove, the first bonding material not filling into space enclosed by the inner wall of the at least one groove; forming a second bonding material on a second surface of a second substrate; and bonding the first bonding material and the second bonding material together in a region except the at least one groove.