In semiconductor manufacturing, silicon carbide (SiC substrates) substrates need to be precisely positioned during various processing steps to ensure accuracy and consistency. To achieve this, specific alignment marks are designed on the substrates. Flat edges and notches are two common types of alignment marks, each with distinct characteristics and applications. This article will detail the principles and uses of these two alignment methods.

What is a Flat edge on a Silicon Carbide Substrate?

A flat edge refers to a straight edge that is ground onto the circumference of a round substrate. Typically, this flat edge is relatively long and occupies a portion of the substrate's circumference.

Why Use a Flat edge?

1. Alignment and Positioning: During semiconductor manufacturing, substrates must be precisely aligned multiple times. A flat edge provides a clear reference point, making alignment easier and more accurate during different processing steps.

2. Equipment Compatibility: Early semiconductor manufacturing equipment primarily used flat edges for alignment. This design facilitates quick recognition and handling by both manual operators and automated systems.

3. Error Reduction: Because the flat edge is long, it is easily detected by inspection equipment, thus reducing the likelihood of errors during processing.

Why Do Some Silicon Carbide Substrates Have Notches?

A notch is a small cut or indentation on the edge of the substrate. It occupies a minimal area but provides precise alignment information.

Why Use a Notch?

1. Increased Precision: A notch offers a more precise alignment point, suitable for high-precision automated equipment. This is particularly important for the high accuracy required in modern semiconductor manufacturing.

2. Material Conservation: Since a notch takes up a minimal area, it doesn't waste much of the substrate's surface area, which is crucial for larger substrates.

3. Minimal Impact Area: Due to its small size, a notch has a negligible impact on the active area of the substrate, helping to maximize its effective utilization.

Specific Applications of Flat edges and Notches

Flat Edges: Primarily used in earlier and smaller-sized silicon carbide substrates (such as those 4 inches or smaller). This design is more suitable for manual handling and early automated equipment.

Notches: Mainly used in modern, high-precision automated production equipment, especially for larger substrates (such as those 6 inches or larger). The notch design meets the high precision and automation requirements.

Conclusion

The design of Flat edges and notches on silicon carbide substrates caters to different equipment and process requirements, ensuring precise positioning of the substrate during manufacturing to maintain process stability and consistency. Flat edges are suitable for early and smaller-sized substrate equipment, while notches are better suited for modern, high-precision, and larger-sized substrate automated equipment.

Understanding the principles and applications of these alignment marks helps in selecting the appropriate silicon carbide substrate to meet various semiconductor manufacturing needs. If you have any questions about choosing silicon carbide substrates, please contact our technical team. We are committed to providing you with professional advice and support.