GaN Semiconductor Chip Wafer Reuse Without Grinding Distortion
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Solution Overview
Problem
The existing manufacturing method for semiconductor chips using gallium nitride (GaN) requires a new GaN wafer for each chip production, reducing productivity and leading to potential defects due to grinding-induced distortion.
Innovation Solution
A method involving the formation of a wafer transformation layer by laser irradiation to separate nitrogen atoms from gallium atoms, allowing the processed wafer to be divided into a chip formation wafer and a recycle wafer, where the recycle wafer is reused, reducing the need for new GaN wafers and minimizing distortion and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a new GaN wafer is used for each chip production, then the quality and consistency of semiconductor chips are maintained, but productivity decreases and manufacturing cost increases
Solution Approach 1:
The patent recovers and reuses the GaN wafer substrate after chip fabrication. The wafer is processed to remove the epitaxial film and chips, then the recovered GaN wafer is prepared for subsequent chip formation processes, enabling multiple reuse cycles and reducing GaN material consumption
Solution Approach 2:
The patent segments the GaN wafer into reusable substrate and disposable epitaxial film/chip components. By separating the valuable GaN wafer from the consumable epitaxial layers, the system enables selective recovery and reuse of the wafer while discarding only the depleted functional layers
2Manufacturing precision
If the processed wafer is ground to reduce thickness, then chip thickness is controlled, but distortion and defects are introduced
Solution Approach 1:
The patent replaces the mechanical grinding process with a chemical etching process using selective etchants. The etchant selectively removes material based on crystal orientation and composition differences, achieving thickness control without the mechanical stress and distortion inherent in grinding
Solution Approach 2:
The patent changes the material removal mechanism from mechanical (grinding) to chemical (etching). By controlling etching parameters such as etchant composition, temperature, and exposure time, precise thickness control is achieved while avoiding the harmful mechanical forces that cause distortion
3Reliability
If the processed wafer is divided into chips after complete fabrication, then chip integrity is maintained, but handling and processing complexity increases
Solution Approach 1:
The patent performs preliminary chip separation actions during the fabrication process itself, creating separation structures and interfaces while the wafer is still intact and easily manipulable. This preliminary segmentation simplifies subsequent handling compared to dividing fully fabricated chips
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 approach enhances productivity by reusing GaN wafers and reduces distortion and defect occurrence in semiconductor chips, facilitating easier handling and improving manufacturing efficiency.
Implementation Method 1
forming a wafer transformation layer by laser irradiation to separate nitrogen atoms from gallium atoms
Implementation Method 2
laser irradiation to separate nitrogen atoms from gallium atoms
Data Source
AI summary
A semiconductor chip includes: an epitaxial film made of gallium nitride; a semiconductor element disposed in the epitaxial film; a chip formation substrate including the epitaxial film and having a first surface, a second surface opposite to the first surface, and a side surface connecting the first surface and the second surface; and a convex and a concavity on the side surface.