Introduction

Laser induced plasma micro-machining (LIPMM) has proved its superiority in micro-machining of hard and brittle materials due to less thermal defects, smaller heat affected zone and larger aspect ratio compared to conventional laser ablation.

Objectives

In order to improve characteristics and stability of induced plasma, this paper proposed magnetically controlled LIPMM (MC-LIPMM) to achieve a good performance of processing single-crystal silicon which is widely used in solid state electronics and infrared optical applications.

Methods

A comprehensive study on surface integrity and geometrical shape was conducted based on the experimental method. Firstly, the mechanism of MC-LIPMM including laser-plasma, laser-materials interactions and transport effects was theoretically analyzed. Then a series of experiments was conducted to completely investigate the effect of magnetic field intensity, pulse repetition frequency, and bubble behavior on surface integrity and geometrical shape of micro channels.

Results

It revealed that magnetic field contributed to maximum reduction of 12.64% for heat affected zone and 62.57% for width while maximum increase of 26.23% for depth and 90.26% for aspect ratio.

Conclusion

This research confirms that MC-LIPMM can improve the machining characteristics of silicon materials and cavitation bubbles shows an apparently negative impact on the surface morphology.

中文翻译：

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磁控激光诱导等离子体微加工单晶硅的加工特性研究

介绍

与传统的激光烧蚀相比，由于较少的热缺陷，较小的热影响区和较大的长径比，激光诱导等离子体微加工（LIPMM）已证明其在硬和脆性材料的微加工中具有优势。

目标

为了改善感应等离子体的特性和稳定性，本文提出了磁控LIPMM（MC-LIPMM），以实现良好的处理单晶硅的性能，这种单晶硅已广泛用于固态电子学和红外光学应用。

方法

基于实验方法对表面完整性和几何形状进行了综合研究。首先，从理论上分析了MC-LIPMM的机理，包括激光等离子体，激光与材料的相互作用以及传输效应。然后进行了一系列实验，以彻底研究磁场强度，脉冲重复频率和气泡行为对微通道表面完整性和几何形状的影响。

结果

结果表明，磁场对热影响区的最大减少量为12.64％，对宽度的最大减少量为62.57％，而深度的最大增加量为26.23％，宽高比的最大减少量为90.26％。

结论

这项研究证实，MC-LIPMM可以改善硅材料的机械加工特性，并且空化气泡对表面形态具有明显的负面影响。