## 1 Introduction  
Polysilicon material is a brittle semiconductor material with high wear resistance, hardness, chemical stability, and low thermal conductivity. The superior performance of silicon materials has secured their use in photovoltaics, aerospace, electronics, and other industries. However, owing to their physical properties, polysilicon and similar semiconductor materials are difficult to process effectively via conventional machining, i.e., the quality of processing may be poor. This problem can be resolved by employing laser processing technology. Such technology is widely used in electronic and other industries for precision machining of difficult-to-machine metal and non-metal material with high hardness, strength, toughness, and brittleness [1; 2; 3]. Unfortunately, under ambient air or inert gas conditions, the transient action of laser heat in the laser processing of materials inevitably produces microcracks and slag on the surface of the material, thereby reducing the qualification rate and processing quality of precision device products. To ameliorate the shortcomings of traditional lasers in processing such materials, liquid-assisted laser technology has been proposed herein. In this technology, with a hard and brittle material, the liquid reduces the temperature gradient at the processing site, thereby avoiding cracking and heat-affected areas of the material and improving the processing quality. Over time, liquid-assisted laser processing technology has branched into water-guided, underwater, and water-jet-assisted laser processing technology. [PERSON] et al. [4] etched trenches into silicon usinga water-guided laser micromachining method. They simulated the melting and removal of silicon under the cooling effect of the water jet and verified their model via comparative simulations and experiments. Their model considers the effects of cutting speed and other factors on the surface quality and heat-affected zone of the workpiece. [PERSON] et al. [PERSON] et al. (2018) applied water-guided laser processing technology to cut metal sheets and summarized the influence of some processing parameters on the results. [PERSON] et al. [PERSON] et al. (2018) cut stainless-steel plates and brass sheets (thickness \(\leq\) 100 \(\upmu\)m) using conventional laser and water-guided laser cutting technologies and compared the cutting widths, heat-affected zones of the two products. Compared to the conventional technique, the water-guided laser cutting system achieved a lower heat-affected zone, slag accumulation height, and slit width. [PERSON] et al. [PERSON] et al. (2018) cut aluminum, titanium, steel, and other metals using a water-guided laser and investigated the effects of laser power, pulse repetition frequency and etching times on the processing quality. The maximum depths of the cut aluminum, titanium, and steel were 8, 4.7, and 1.5 mm, respectively, and the maximum aspect ratios were 66.7, 39.2 and 12.5, respectively. Using Nd:YAG pulse fiber lasers, [PERSON] et al. [PERSON] et al. (2018) conducted stainless-steel plate experiments in both air and underwater environments. Their results demonstrate that compared to air cutting, underwater cutting improves the sample and slightly reduces its slit width, heat-affected zone, and adhesion slag. [PERSON] et al. [PERSON] et al. (2018) established a model for investigating the energy-loss mechanism in underwater laser cutting. The model accounts for the interaction between the laser, material, and water. Most of the energy is lost by the scattering of the laser light in water vapor. The losses account for 40-50% of the total laser energy. The correctness of the model results was verified via experiments. [PERSON] (2018) processed LCD glass materials using underwater and conventional laser techniques and investigated the effects of the laser parameters, material size, and liquid type on the removal rate, slit width, incision depth, taper, and surface roughness of the processed materials.