In semiconductor manufacturing processes, one of the devices used to hold wafers in place is the porous chuck.

The porous chuck uses vacuum to secure the wafer, and is primarily used in processes where maintaining wafer flatness and precise positioning is critical.

1. Principle and Structure

• Principle: The porous chuck has a porous structure that creates a vacuum, which holds the wafer in place. The pressure difference between the wafer and the chuck surface in the vacuum state causes the wafer to adhere firmly to the chuck surface.
• Porous Structure: The chuck's surface is composed of fine holes that can create a vacuum.
• Vacuum Channels: Inside the chuck, there are channels that generate and distribute the vacuum.
• Surface Coating: The surface is coated with a special coating to optimize friction with the wafer and prevent damage.

2. Main Applications

• Photolithography: Keeping the wafer flat and fixed in an exact position is crucial. The porous chuck prevents minute movements of the wafer, enhancing the precision of patterns.
• Etching and Deposition: Uniform treatment of the wafer surface is necessary. The porous chuck, using vacuum, minimizes wafer deformation, enabling uniform processing.
• Planarization: Used in processes that make the wafer surface flat. The porous chuck stabilizes the wafer, maximizing the effectiveness of the planarization process.

3. Advantages of the Porous Chuck

• Uniform Clamping Force: Provides a uniform clamping force across the entire wafer using vacuum. This minimizes wafer deformation and enhances process consistency.
• Damage Prevention: Reduces direct contact between the wafer and the chuck, minimizing wafer damage. This is particularly suitable for thin and sensitive wafers.

The porous chuck is a crucial device in semiconductor manufacturing processes, enabling precise wafer fixation, especially in high-precision processes and handling sensitive wafers.