Mask-less ultraviolet photolithography based on CMOS-driven micro-pixel light emitting diodes

Area of Science:

• Materials Science
• Optics and Photonics
• Microfabrication

Background:

• Traditional photolithography methods face challenges in achieving high resolution and precise dose control.
• Direct writing techniques offer flexibility but often lack the throughput and precision required for advanced microfabrication.

Purpose of the Study:

• To develop and demonstrate a novel UV photolithography and direct writing system.
• To enable precise control over exposure pattern and dose using a CMOS-controlled micro-pixel LED array.

Main Methods:

• Utilized a complementary metal oxide semiconductor (CMOS) controlled 8x8 gallium nitride micro-pixel LED array emitting 370 nm UV light.
• Employed a projection system with two back-to-back microscope objectives for controlled demagnification.
• Achieved pixel spot sizes of approximately 8 micrometers with power density up to 8.8 W/cm².

Main Results:

• Successfully demonstrated UV photolithography and direct writing with controlled exposure patterns and doses.
• Showcased the system's capability to write structures in both positive and negative photoresists.
• Validated the precision and resolution of the micro-pixellated LED array projection system.

Conclusions:

• The developed micro-pixellated LED array system offers a promising approach for advanced UV photolithography and direct writing.
• This technology enables high-resolution patterning with precise dose control, suitable for microfabrication applications.
• The system's flexibility and precision pave the way for new possibilities in micro-device fabrication.