SiC Wafer Segmentation via Laser Separation

The SiC ingot is segmented into multiple thin slices using laser beam processing, creating multiple usable wafers from a single ingot. This segmentation approach allows the hard SiC material to be processed into thin, usable forms without requiring excessive thinning of each individual wafer, thereby reducing manufacturing cost while maintaining the energy efficiency benefits of SiC devices.

The patent replaces traditional mechanical thinning methods with laser beam processing. The laser beam forms separation layers inside the SiC ingot through optical-thermal interaction, eliminating the need for prolonged mechanical grinding and polishing. This substitution dramatically reduces processing time and cost while enabling the formation of thin SiC wafers suitable for device fabrication.

Conventional mechanical thinning methods are replaced with laser beam processing. The laser beam rapidly forms separation layers inside the SiC ingot through optical absorption and thermal effects, reducing processing time from hours to minutes. This allows device formation to proceed without the excessive time consumption associated with mechanical thinning of hard SiC material.

The laser beam induces phase transitions in the SiC material during separation layer formation. By controlling the laser parameters, the material undergoes localized melting and resolidification, creating clean separation layers that enable rapid wafer slicing. This phase transition mechanism allows fast processing while maintaining the quality needed for subsequent device formation steps.

Instead of thinning a single thick wafer to the required thickness (which discards most of the material), the SiC ingot is segmented into multiple thin wafers of appropriate thickness. Each segment becomes a usable wafer, maximizing material utilization. This segmentation approach ensures that nearly all SiC material from the ingot is converted into manufacturable wafers, dramatically reducing material wastage while achieving the required thickness precision.

Separation layers are formed preliminarily within the SiC ingot before slicing into wafers. This preliminary action creates predetermined planes that guide the slicing process, ensuring that each resulting wafer has the correct thickness. By establishing these separation layers in advance, the process eliminates the need to discard excess material during subsequent thinning operations, as the correct thickness is achieved during the segmentation process itself.

Complex mechanical thinning operations are replaced with a single laser beam processing step. The laser system, while technologically sophisticated, consolidates multiple mechanical steps (grinding, polishing, measurement) into one automated process. The laser parameters (power, speed, focus) are programmed to automatically create separation layers at precise depths, reducing operational complexity despite the advanced technology involved.

The laser processing parameters (wavelength, power, scanning speed, focal depth) are optimized and standardized for SiC material. By establishing fixed parameter sets for different wafer thickness requirements, the processing complexity is managed through parameter selection rather than complex procedural steps. This parameter-based approach allows efficient separation layer formation while keeping the process relatively simple and repeatable.