Grinding of SiC Device Wafers

Solutions

SiC (silicon carbide) is a semiconductor material with high voltage resistance and low power loss, and SiC wafers are used in power devices. SiC power devices generally have a vertical device structure, and thinning the wafer lowers the substrate resistance, leading to improved energy conversion efficiency. However, SiC is well known as a difficult-to-process material that has a high rigidity compared to Si, making dedicated applications and wheels necessary for the thinning process.

SiC Thinning Process Examples

2-axis Processing

2-axis process (rough/fine grinding)

Productivity Improvement Through 4-axis Processing

A process that improves the productivity by distributing rough grinding, which is the bottleneck process, between 4 axes

Quality Improvement Using Dry Polishing

A process that improves the quality by performing dry polishing after 2-axis grinding

SiC Wafer Processing Examples

SiC Wafer Surface Condition Comparison (SEM Images)

The following is a comparison of the wafer surface condition when processed using standard parameters.
It can be seen that the surface condition improves in the order of rough grinding, fine grinding, and dry polishing.

After rough grinding
After fine grinding
After dry polishing

Photographs of a processed SiC wafer taken using SEM (scanning electron microscope)

Die Strength Comparison of SiC Wafers

The following is a die strength comparison between a wafer after fine grinding and a wafer after dry polishing when processed using standard parameters.
It can be seen that the die strength improves significantly after dry polishing.

Die strength may vary depending on the wafer or processing conditions.

Measurement conditions:
Wafer processed	6-inch SiC wafer
Finish thickness	0.15 mm
Die size	10 mm × 10 mm
Measurement method	Ball-point bending test

Recommended Wheel

GFSC Series: Grinding Wheels for SiC Wafers

SiC is a highly rigid material, and as it is difficult to perform stable grinding and achieve high quality, a grinding wheel that has a high grinding performance is required.
The GFSC Series can achieve stable rough/fine grinding for SiC wafers by reducing the grinding load, and improved processing quality and wheel life can also be expected.