GaN Wafer Marking by Gallium Deposition to Prevent Cracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gallium nitride (GaN) wafers are fragile and prone to cracking when identification marks are formed on their surface, as the recessed portions created by traditional marking processes can serve as starting points for cracks.
Innovation Solution
A method for manufacturing semiconductor chips that involves forming an identification mark by depositing gallium inside the GaN wafer, rather than creating a recessed portion on the surface, thereby suppressing the formation of cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a recess portion is formed on the surface of the GaN wafer by laser beam to create an identification mark, then the mark is successfully formed, but cracks occur in the GaN wafer starting from the recessed portion
Solution Approach 1:
Instead of removing material to form the mark (recess portion), the invention deposits material (gallium) onto the surface to form an elevated mark. This inversion of the marking approach eliminates stress concentration points that would otherwise initiate cracks, thereby maintaining wafer strength while achieving identification marking.
Solution Approach 2:
The invention changes the physical state and distribution of gallium on the wafer surface. By controlling laser irradiation parameters and gallium deposition conditions, the surface gallium concentration is increased to form a visible mark without creating recesses. This parameter change transforms the marking process from material removal to material addition, preventing crack formation.
2Manufacturing precision
If the GaN wafer surface is polished after recess formation, then the recess portion remains as an identification mark, but the crack risk increases due to the recessed structure
Solution Approach 1:
The invention inverts the traditional marking approach by creating an elevated gallium deposit rather than a recessed portion. This eliminates the stress concentration inherent in recessed structures while maintaining mark visibility, thereby improving reliability without sacrificing manufacturing precision.
Solution Approach 2:
The invention converts the potential harm of laser irradiation (which could create defects and cracks) into a beneficial process by using controlled laser heating to facilitate gallium deposition. The laser energy that might otherwise damage the wafer is instead used to mobilize and deposit gallium atoms onto the surface, creating a visible mark while strengthening the surface structure.
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 effectively prevents cracking in GaN wafers during the formation of identification marks, ensuring the integrity and reliability of the semiconductor chips produced.
Implementation Method 1
forming a wafer transformation layer, in which nitride is separated from gallium, along a planar direction of the processed wafer by irradiating an inside of the processed wafer with a laser beam from the second surface side of the processed wafer
Implementation Method 2
forming a mark inside of one of the gallium nitride wafer and the processed wafer by irradiating an inside of the one with a laser beam, the mark being formed by a deposition of gallium
Data Source
AI summary
A manufacturing method for a semiconductor chip includes: preparing a GaN wafer; producing a processed wafer by forming an epitaxial film on a surface of the GaN wafer to have chip formation regions adjacent to a first surface of the processed wafer; forming a first surface-side element component of a semiconductor element in each chip formation region; forming a wafer transformation layer along a planar direction of the processed wafer by irradiating an inside of the processed wafer with a laser beam; dividing the processed wafer at the wafer transformation layer into a chip formation wafer and a recycle wafer; extracting a semiconductor chip from the chip formation wafer; and after the preparing the GaN wafer and before the dividing the processed wafer, irradiating an inside of the gallium nitride wafer or the processed wafer with a laser beam to form a mark by deposition of gallium.