Femtosecond versus nanosecond laser machining: comparison of induced stresses and structural changes in silicon wafers

In this work, nanosecond laser machining is used to fabricate hydrophobic 17-4 PH stainless steel surfaces with microscale and submicron structures. Four surface structures were designed, with microscale channels and pillars (100 μm pitch size) of uniform heights (100 μm) or alternating heights (between 100 μm and 50 μm). During fabrication, the high-power laser beams also created submicron features on top of the microscale ones, leading to hierarchical, multiscale surface structures. Detailed wettability analysis was conducted on the fabricated samples. Measured static contact angles of water on these surfaces are over 130 deg without any coating, compared to ∼70 deg on the original steel surface before laser machining. Slightly lower contact angle hysteresis was also observed on the laser machined surfaces. Overall, these results agree with a simple Cassie–Baxter model for wetting that assumes only fractional surface area contact between the droplet and the surface. This work demonstrates that steel surfaces machined with relatively inexpensive nanosecond laser can achieve excellent hydrophobicity even with simple microstructural designs.

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Millisecond laser machining of transparent materials assisted by nanosecond laser

Optics Express ◽

10.1364/oe.23.000765 ◽

2015 ◽

Vol 23 (2) ◽

pp. 765 ◽

Cited By ~ 15

Author(s):

Yunxiang Pan ◽

Hongchao Zhang ◽

Jun Chen ◽

Bing Han ◽

Zhonghua Shen ◽

...

Keyword(s):

Laser Machining ◽

Nanosecond Laser ◽

Transparent Materials ◽

Millisecond Laser

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Study of structural changes caused by nanosecond laser annealing of Ge- and Sn-implanted Si crystal

Radiation Physics and Chemistry ◽

10.1016/j.radphyschem.2011.03.017 ◽

2011 ◽

Vol 80 (10) ◽

pp. 1064-1067

Author(s):

D. Klinger ◽

D. Żymierska ◽

R. Minikayev ◽

K. Nowakowska-Langier ◽

J.B. Pelka ◽

...

Keyword(s):

Structural Changes ◽

Laser Annealing ◽

Nanosecond Laser

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Structural Changes in Polymethyl Methacrylate during Laser Machining

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/448/1/012047 ◽

2018 ◽

Vol 448 ◽

pp. 012047

Author(s):

L Sýkorová ◽

J Knedlová ◽

V Pata ◽

M Kubišová

Keyword(s):

Polymethyl Methacrylate ◽

Structural Changes ◽

Laser Machining

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Influence of the grain size of CVD diamond on the thermal conductivity, material removal depth and surface roughness in nanosecond laser machining

Ceramics International ◽

10.1016/j.ceramint.2020.05.157 ◽

2020 ◽

Vol 46 (12) ◽

pp. 20510-20520 ◽

Cited By ~ 3

Author(s):

Zhenjun Li ◽

Ni Chen ◽

Liang Li ◽

Yang Wu ◽

Ning He

Keyword(s):

Thermal Conductivity ◽

Surface Roughness ◽

Grain Size ◽

Material Removal ◽

Cvd Diamond ◽

Laser Machining ◽

Nanosecond Laser

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Structural Changes in Metals during Laser Cutting

Materials Science Forum ◽

10.4028/www.scientific.net/msf.919.25 ◽

2018 ◽

Vol 919 ◽

pp. 25-33

Author(s):

Libuše Sýkorová ◽

Oldřich Šuba ◽

Vladimír Pata ◽

Milena Kubišová

Keyword(s):

Temperature Field ◽

Laser Beam ◽

Laser Cutting ◽

Structural Changes ◽

Hardness Measurement ◽

Laser Machining ◽

Transient Temperature ◽

Transient Temperature Field ◽

Metal Materials ◽

Cutting Point

The presented paper deals with the problems associated with laser machining of metal materials. Specifically, it solves the question of structural changes that occur as a result of the transfer of heat to the material. Experimental machining of selected technical materials was carried out, and on the basis of the hardness measurement near the cutting point, the heat-affected zone was evaluated after passing the laser beam. To confirm the detection of the affected zone width the models of transient temperature field were arranged, to represent the distribution of temperature in the vicinity of the cutting edge.

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Laser-Assisted Waterjet Micro-Grooving of Silicon Wafers for Minimizing Heat Affected Zone

Materials Science Forum ◽

10.4028/www.scientific.net/msf.861.133 ◽

2016 ◽

Vol 861 ◽

pp. 133-138

Author(s):

Xiang Ning Pan ◽

Chuan Zhen Huang ◽

Jun Wang ◽

Hong Tao Zhu ◽

Peng Yao

Keyword(s):

Heat Affected Zone ◽

Predictive Models ◽

Functional Materials ◽

Groove Depth ◽

Silicon Wafers ◽

Machining Process ◽

Laser Machining ◽

Micro Machining ◽

Micro Grooving ◽

Haz Width

Laser-assisted waterjet micro-machining can significantly reduce the thermal damages to the workpiece as compared to the traditional laser machining process, and hence can overcome the problems associated with laser machining, such as the formation of heat-affected zone, which is a serious issue for thermal sensitive and functional materials. An experimental study on micro-grooving of monocrystalline silicon wafers is reported in this study to explore the effects of process parameters on the groove depth and width as well as the heat-affected zone (HAZ) width. Predictive models based on dimensionl analysis are then developed for estiamting the groove characteristics.

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