Optical projection system design for photoresist exposure

Area of Science:

• Microfabrication
• Optical Engineering
• Materials Science

Background:

• Contact printing in microcircuit fabrication poses risks of damage to silicon wafers and glass masters.
• Conventional projection printing criteria are unsuitable for etched photoresists due to their lack of grayscale properties.
• Developing alternative printing methods is crucial for advancing microcircuit manufacturing.

Purpose of the Study:

• To establish adequate criteria for projection printing onto photoresists.
• To explore the feasibility of replacing contact printing with projection printing in microcircuit exposure.
• To address the limitations of conventional projection printing for non-grayscale photoresist materials.

Main Methods:

• Examination of the imaging properties of diffraction-limited optical systems.
• Analysis of the recording characteristics of photoresists.
• Development and proposal of a novel criterion based on edge uncertainty of lines.

Main Results:

• A new criterion for projection printing on photoresists, based on edge uncertainty, has been proposed.
• The study highlights the importance of understanding optical imaging and photoresist properties for projection printing.
• Consideration of other relevant aspects of projection systems was included.

Conclusions:

• The proposed edge uncertainty criterion provides a viable method for projection printing onto photoresists.
• Projection printing is a promising alternative to contact printing for microcircuit fabrication, mitigating direct contact issues.
• Further investigation into projection systems can optimize microcircuit manufacturing processes.