Optimization of coating uniformity in a simple rotation system by using a rotating shadow mask

Area of Science:

• Optical engineering
• Thin film deposition

Background:

• Achieving uniform film thickness in large-aperture optical components is critical for performance.
• Simple rotation systems often struggle with uniformity, especially near the center of substrates.

Purpose of the Study:

• To develop a theoretically designed rotating shadow mask system to enhance film thickness uniformity.
• To enable the fabrication of large-aperture optical components using existing coating machinery.

Main Methods:

• Theoretical design and simulation of a rotating shadow mask.
• Calculation of an additional fixed shadow mask to complement the rotating mask.
• Integration of both masks to correct film thickness non-uniformities.

Main Results:

• The rotating shadow mask effectively corrects uniformity near the center of plane substrates.
• The combined system achieves approximately 99.5% uniformity over a 640 mm diameter.
• The method efficiently utilizes the coating chamber width for large component fabrication.

Conclusions:

• The proposed dual rotating and fixed shadow mask system significantly improves film thickness uniformity.
• This technique allows for the cost-effective production of large-diameter optical components.
• The design offers a practical solution for optimizing simple rotation coating systems.