Inspection of silicon carbide boules (SiC)

LOTOS

3D measurement and inspection

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Fully automatic inspection of silicon carbide boules

Achieving the stringent zero defect strategy in the industry is becoming a major challenge for silicon carbide substrate manufacturing. Both the switch from 150 to 200 mm silicon carbide wafer and the general shift in their focus away from pure silicon are making the processes struggling to achieve sufficient yields and reliability.

LOTOS metrology scanner help implementing the zero-defect strategy toward high-yield production processes without any scrap. Shortly after crystal growing, silicon carbide boules can be inspected for chipping, geometric sizes and false polytypes or doping, eliminating scrap in subsequent production processes.

LOTOS checks all common parameters such as:

  1. Chip sizes, positions and remaining area for usage
  2. Outer diameter
  3. Diameter at the primary and secondary flat
  4. Flat lengths
  5. Flatness of Flat
  6. Notch contours
  7. Angular positions of notch and flat
  8. Boule thickness at any position
  9. oTTV/TTV (Total thickness variation)

Furthermore, the boules can be inspected for inclusions of false polytypes.

Silicon carbide boules - Chip checking


Detection of Chipping, Cracks, Scratches, and Other Surface Defects

The system is equipped with advanced detection capabilities to identify and analyze a wide range of surface defects such as chipping, cracks, scratches, and other irregularities. It employs high-resolution imaging and machine learning techniques to ensure accurate and reliable results in the form of a 3D scan.

The system generates detailed outputs for each detected defect, which include:

  1. Depth (for cracks or chips)
  2. Position: The exact coordinates of each defect on the surface, allowing for precise location identification for further analysis or repairs.
  3. Length: The measured length of the defect, providing an indication of how extensive the damage is.
  4. Width
  5. Number of Defects: The total count of surface irregularities detected during the inspection process.

Silicon carbide UV inspection

Polytype-selective growth of silicon carbide (SiC) plays a pivotal role in the production of a high-performance silicon carbide semiconductor. Silicon carbide exists in multiple polytypes, most notably 4H-SiC and 6H-SiC, which exhibit distinct electrical, mechanical, and thermal properties. The objective of this quality control of the silicon carbide boule structure is to ensure the proper formation of the desired polytype (4H or 6H) in the silicon carbide boules, as well as to monitor the impact of doping variations on polytype stability and growth quality.

It is essential for ensuring the uniformity and consistency of the silicon carbide crystal structure and electrical properties across the SiC boule material.

Performing quality control on silicon carbide boules with different polytypes and doping levels ensures the consistency and reliability of the material for device applications. Regular monitoring and testing of these boules are critical to maintaining optimal material performance and meeting production specifications.

Silicon carbide boule thickness

The system measures the thickness of boules or pucks at various positions along their surface to accurately assess the utilizable SiC boule material. Using these measurements to calculate the maximum usable volume of the silicon carbide crystal, ensures the most efficient use of resources. This will help to maximize yield by minimizing waste and optimizing the processing of each SiC boule material.

Measure dimensions of silicon carbide boules

It is essential to measure the physical dimensions of boules or pucks with the highest precision in order to verify that all relevant dimensional characteristics align with the specified criteria. This includes a thorough measurement of the notch depth to ensure it meets the defined requirements. Furthermore, a comprehensive quality control of the notch angle and radius is necessary to confirm the prescribed standards. In addition, any other relevant geometric features should be verified, as they may impact the functionality and performance of further boule processing.

Exemplary measurements

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Whatever your request, we‘re here for you.
Whatever your request, we are here for you! Just enter contact details and the subject of your request and we will be happy to get back to you personally.
Or e-mail to: info(at)kocos.com
Contact   

Let‘s stay in touch!
Subscribe to the KoCoS newsletter and be the first to know about our products, updates and other news.
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