Micro-Ball Lens Array Fabrication in Photoresist Using Ptfe Hydrophobic Effect

TL;DR

This paper introduces a simple, cost-effective method for fabricating micro-ball lens arrays using the hydrophobic properties of PTFE to shape melted photoresist into spherical lenses.

Contribution

It demonstrates a novel fabrication technique leveraging PTFE's hydrophobicity to produce micro-ball lens arrays with a straightforward process.

Findings

Micro-ball lenses with 98 μm diameter were successfully fabricated.

The method is simple, low-cost, and suitable for mass production.

Different micro-column diameters can be used to control lens size.

Abstract

This paper presents a simple method to fabricate micro-ball lens and its array. The key technology is to use the hydrophobic characteristics of polyterafluoroethylene (PTFE) substrate. High contact angle between melted photoresist pattern and PTFE can generate micro-ball lens and its array. PTFE thin film was spun onto a silicon wafer and dried in oven. Photoresist AZ4620 was used to pattern micro-columns with different diameters 60, 70 and 80 $\mu$m. A thermal reflow process then was applied to melt these micro-column patterns resulted in micro-ball lens array. The achieved micro-ball lens array with diameter 98 $\mu$m was fabricated using 80 $\mu$m in diameter patterns. This method provides a simple fabrication process and low material cost.