Automated alignment in mask‐free photolithography enabled by micro‐LED arrays

Abstract

Abstract We present an automated control system for micro scale positioning, based on single pixel imaging and fluorescence. By projecting a chequerboard array of CMOS controllable μ‐LEDs at a suitable wavelength, we are able to spatially locate, track and automatically align to fluorescent markers. Positioning is demonstrated with accuracy on the order of 20 μm. We present a maskless photo‐lithography system using the automated control capability and a second μ‐LED array to photo‐cure customisable structures in photoresist with alignment referenced to the fluorescent markers.

Keywords

• CMOS integrated circuits
• Optical, image and video signal processing
• Computer vision and image processing techniques
• Light emitting diodes
• Lithography (semiconductor technology)