Excimer Laser Three-Dimensional Micromachining Based on Image Projection and the Optical Diffraction Effect

Yu-Hsuan Hung,Hung-Liang Chien,Yung-Chun Lee

doi:10.3390/app8091690

Yu-Hsuan Hung, Hung-Liang Chien + Show 1 more

Open Access

https://doi.org/10.3390/app8091690

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Abstract

An excimer laser three-dimensional (3D) micromachining system is proposed based on a mask image projection method and the optical diffraction effect. The effects of optical diffraction on the laser machining rate are evaluated using a hole-arrayed mask pattern with various feature sizes and hole-area opening ratios. The practical feasibility of the proposed method is demonstrated by machining conical, trihedral, and pyramidal 3D microstructures on polycarbonate substrates. The proposed method greatly simplifies the photo-mask design and preparation task in traditional excimer laser 3D micromachining systems and provides a powerful technique for achieving large-area 3D microstructures with complex patterns and atypical profiles.

Highlights

The direct machining of microstructures by pulsed excimer lasers has attracted significant interest over the past 30 years or so [1,2,3]
The system consists of an excimer laser source, a laser beam homogenizer, a photo-mask, an optical image projection system, and a multi-axis translation stage
The light passing through the mask is projected by an optical imaging system onto the surface of the sample, which is mounted on a servo-controlled multi-axis translation stage

Summary

Introduction

The direct machining of microstructures by pulsed excimer lasers has attracted significant interest over the past 30 years or so [1,2,3]. This technique, known as contour mask scanning [7,8,9,10,11,12,13,14,15], results in the formation of a 3D substrate), the 3D microstructures are obtained through a careful control of the relative movement machined profile through the superposition of multiple 2D machined patterns appropriately between the laser-projected photo-mask pattern and the sample under a specific firing sequence of distributed at different locations and orientations. Through an appropriate design of the projected laser fluence and laser machining rate, the distribution of the machining depth on the sample can be varied as required to realize micro-features with different 3D profiles In implementing such systems, designing suitable transmission-varying masks poses a significant challenge.

The Excimer Laser Micromachining System and the Optical Diffraction Effect

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Conclusions