scholarly journals Sub-Picosecond Micromachining of Monocrystalline Silicon for Solar Cell Manufacturing

2020 ◽  
Vol 10 (20) ◽  
pp. 7277
Author(s):  
Katarzyna Garasz ◽  
Marek Kocik
Keyword(s):  
Solar Cell ◽  
Picosecond Laser ◽  
Processing Parameters ◽  
Optimal Parameters ◽  
Ultrashort Pulse Laser ◽  
Reliable Source ◽  
Laser Systems ◽  
Cost Efficient ◽  
Telecentric Lens

In this study a prototype sub-picosecond laser was investigated for cutting and scribing of silicon wafers. The Yb:KYW laser used for this investigation, unlike ultrashort systems used previously, generates pulses of 650 fs, i.e., between the pico and femtosecond range. The laser was placed in a micromachining setup, involving a galvo scanner and a telecentric lens. A study of the influence of the processing parameters on the crater width, depth, and quality of machining was carried out. The optimal parameters were found to be 343 nm, 200 kHz, 7 mm/s, and 15 pattern repetitions. The experiments were performed using samples of a silicon wafer of 210-µm thickness. The experimental results show that the sub-picosecond laser can be a promising and competitive tool for solar cell micromachining. In comparison to the commercially available ultrashort pulse laser systems, we find the sub-picosecond laser to be a more cost efficient and reliable source, than a femtosecond one. In addition, the prototype Yb:KYW design offers some unique parameters, such as repetition rate in the range of 100–400 kHz, UV wavelength or obtainable laser fluence close to the silicon ablation thresholds.

Effect of Laser Processing Parameters on Microhole Quality of Aluminium Nitride Ceramics

2021 ◽  
Vol 871 ◽  
pp. 277-283
Author(s):  
Chun Yan Yang ◽  
Yun Hao ◽  
Bozhe Wang ◽  
Hai Yuan ◽  
Liu Hui Li
Keyword(s):  
Laser Processing ◽  
Laser Power ◽  
Picosecond Laser ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Recast Layer ◽  
Aluminium Nitride ◽  
Obvious Effect ◽  
Nitride Ceramics

A picosecond laser in spin-cutting mode was used to drill 500μm diameter microholes on 150μm thick aluminium nitride ceramic. The effects of laser processing parameters such as the laser power, scanning speed, and defocus amount on the microhole quality were studied. The results show that as the laser power increases, the inlet and outlet diameters of the holes increase, the taper decreases slightly, and the thickness of the recast layer decreases evidently. The scanning speed has no obvious effect on the diameter and taper of the hole; however, the hole can not be drilled through when the speed is too large. Positive defocus can effectively reduce the taper of the hole. Under 28.5W laser power, 400Hz frequency, 200mm/s scanning speed, and zero defocus amount conditions, high-quality microholes with a taper of 0.85° were obtained.

scholarly journals Microdrilling of Through-Holes in Flexible Printed Circuits using Picosecond Ultrashort Pulse Laser

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1390 ◽  
Author(s):  
Wanqin Zhao ◽  
Lingzhi Wang
Keyword(s):  
Pulse Laser ◽  
Ultrashort Pulse ◽  
Small Diameter ◽  
Processing Parameters ◽  
Good Choice ◽  
High Density ◽  
Ultrashort Pulse Laser ◽  
Electronic Products ◽  
Printed Circuits

High density and high quality interconnects are necessary for the preparation of miniaturized and lightweight electronic products. Therefore, small-diameter and high-density through-holes in FPCs (Flexible Printed Circuits) are required. However, the current processing methods cannot further decrease the diameters and improve the quality of through-holes. Comparatively, ultrashort pulse laser is a good choice. In this paper, the processing technology for the microdrilling of through-holes in FPCs using a 10 ps pulse laser was systematically studied. The effects of laser parameters, including the wavelength, energy, pulses and polarization, on the drilling of through-holes were investigated. The various processing parameters were optimized and the plausible reasons were discussed. Finally, the desired small-diameter and high-density through-holes in FPCs were obtained. The experimental results showed that, through-holes with diameters of less than 10 µm and inlet interconnection pitches of 0 ~ 2 µm could be successfully drilled in FPCs using ultrashort pulse laser.

Data-based prediction of microbial contamination in herbs and identification of optimal harvest parameters

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Stefan Anlauf ◽  
Andreas Haghofer ◽  
Karl Dirnberger ◽  
Stephan Winkler
Keyword(s):  
Analysis Data ◽  
Processing Parameters ◽  
Storage Conditions ◽  
Gradient Boosting ◽  
Optimal Processing ◽  
Optimal Harvest ◽  
Cost Efficient ◽  
Harvesting Process ◽  
And Storage

Abstract The quality of freshly harvested herbs is affected by several crucial factors, such as weather, tillage, fertilization, drying, and the harvesting process, e.g. Our main goal is to learn models that are able to predict spore contaminations in different types of herbs on the basis of information about the harvesting process, transport conditions, drying, and storage conditions. This shall enable us to identify optimal processing parameters, which will allow more effective and cost efficient contamination prevention. Using machine learning, we have generated ensembles of models that predict the risk for spore contamination on the basis of harvest processing parameters. The training information about contamination in herbs is given as results of laboratory analysis data. We applied different modeling algorithms (random forests, gradient boosting trees, genetic programming, and neural networks). In this paper we report on modeling results for yeast and mold contaminations in peppermint and nettle; e.g., for yeast contamination in peppermint we obtained models with 78.13% accuracy. Additionally, we use descriptive statistics to identify those parameters that have a statistically significant influence on the contamination; for example, our analysis shows that there seems to be a relationship between mold in peppermint and information about harrowing and the growth height (p = 0.001).

Quality Evaluation Techniques of Solar Cell Module

2010 ◽  
Author(s):  
Daisuke Murahara ◽  
Wataru Shimizu ◽  
Hidehisa Kubota ◽  
Tamiko Oda ◽  
Kazuhiro Yabe
Keyword(s):  
Solar Cell ◽  
Process Diagnostics ◽  
Photovoltaic Energy ◽  
Module Selection ◽  
Cell Modules ◽  
Diagnostics System ◽  
Photovoltaic Technologies ◽  
Evaluation Techniques

Abstract We have developed a process diagnostics system for photovoltaic energy modules based on standard methods and practices already developed for LSI and MEMS technologies. This paper provides a description of methods used to ensure the conformation of solar cell modules to the rigors of high-quality manufacturing necessary for reliable photovoltaic energy production when exposed to long-term environmental use. We have verified the possibility of inspecting each solar cell and the module assembly in detail for several photovoltaic technologies, specifically monocrystalline Si, polycrystalline Si, and CuInxGa1-xSe2 An objective set of criteria for the quality of each module can be provided by this method for use in module selection by consumers. Moreover, the quality of conformance and reliability data can be used as feedback to the manufacturer to minimize the number of defects created during manufacturing process and ameliorate their effects.

scholarly journals Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE Materials

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1795
Author(s):  
Norshahira Roslan ◽  
Shayfull Zamree Abd Rahim ◽  
Abdellah El-hadj Abdellah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Katarzyna Błoch ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Thick Plate ◽  
Processing Parameters ◽  
Processing Parameter ◽  
Plastic Injection Moulding ◽  
Optimal Setting ◽  
Quality Of Products ◽  
Validation Tests ◽  
Plastic Injection

Achieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.

scholarly journals Virtual Router Design and Modeling for Future Networks with QoS Guarantees

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1139
Author(s):  
Mykola Beshley ◽  
Natalia Kryvinska ◽  
Halyna Beshley ◽  
Oleg Yaremko ◽  
Julia Pyrih
Keyword(s):  
Quality Of Service ◽  
Dynamic Reconfiguration ◽  
Future Internet ◽  
End Users ◽  
Mathematical Representation ◽  
Optimal Parameters ◽  
Resource Virtualization ◽  
Virtual Routers ◽  
Network Device

A virtual router model with a static and dynamic resource reconfiguration for future internet networking was developed. This technique allows us to create efficient virtual devices with optimal parameters (queue length, queue overflow management discipline, number of serving devices, mode of serving devices) to ensure the required level of quality of service (QoS). An analytical model of a network device with virtual routers is proposed. By means of the mentioned mathematical representation, it is possible to determine the main parameters of the virtual queue system, which are based on the first in, first out (FIFO) algorithm, in order to analyze the efficiency of network resources utilization, as well as to determine the parameters of QoS flows, for a given intensity of packets arrival at the input interface of the network element. In order to research the guaranteed level of QoS in future telecommunications networks, a simulation model of a packet router with resource virtualization was developed. This model will allow designers to choose the optimal parameters of network equipment for the organization of virtual routers, which, in contrast to the existing principle of service, will provide the necessary quality of service provision to end users in the future network. It is shown that the use of standard static network device virtualization technology is not able to fully provide a guaranteed level of QoS to all present flows in the network by the criterion of minimum delay. An approach for dynamic reconfiguration of network device resources for virtual routers has been proposed, which allows more flexible resource management at certain points in time depending on the input load. Based on the results of the study, it is shown that the dynamic virtualization of the network device provides a guaranteed level of QoS for all transmitted flows. Thus, the obtained results confirm the feasibility of using dynamic reconfiguration of network device resources to improve the quality of service for end users.

scholarly journals Development of a single-shot third-order cross-correlator for picosecond laser systems

2021 ◽  
Vol 483 ◽  
pp. 126672
Author(s):  
A.C. Aiken ◽  
P. Oliveira ◽  
L.E. Bradley ◽  
E. Dilworth ◽  
M. Galletti ◽  
...  
Keyword(s):  
Picosecond Laser ◽  
Single Shot ◽  
Third Order ◽  
Laser Systems

Observation in the Surface Roughness of Silicon Wafer during Semi-Fixed Abrasive Machining with Large Grains

2009 ◽  
Vol 69-70 ◽  
pp. 253-257
Author(s):  
Ping Zhao ◽  
Jia Jie Chen ◽  
Fan Yang ◽  
K.F. Tang ◽  
Ju Long Yuan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Silicon Wafer ◽  
Processing Parameters ◽  
Wafer Surface ◽  
Abrasive Machining ◽  
Fixed Abrasive ◽  
Is Failure ◽  
Better Than

Semi-fixed abrasive is a novel abrasive. It has a ‘trap’ effect on the hard large grains that can prevent defect effectively on the surface of the workpiece which is caused by large grains. In this paper, some relevant experiments towards silicon wafers are carried out under the different processing parameters on the semi-fixed abrasive plates, and 180# SiC is used as large grains. The processed workpieces’ surface roughness Rv are measured. The experimental results show that the surface quality of wafer will be worse because of higher load and faster rotating velocity. And it can make a conclusion that the higher proportion of bond of the plate, the weaker of the ‘trap’ effect it has. Furthermore the wet environment is better than dry for the wafer surface in machining. The practice shows that the ‘trap’ effect is failure when the workpiece is machined by abrasive plate which is 4.5wt% proportion of bond in dry lapping.

On the Field Evaporation Behavior of a Model Ni-Al-Cr Superalloy Studied by Picosecond Pulsed-Laser Atom-Probe Tomography

2008 ◽  
Vol 14 (6) ◽  
pp. 571-580 ◽  
Author(s):  
Yang Zhou ◽  
Christopher Booth-Morrison ◽  
David N. Seidman
Keyword(s):  
Atom Probe Tomography ◽  
Mass Spectra ◽  
Pulsed Laser ◽  
Picosecond Laser ◽  
Atom Probe ◽  
Resolving Power ◽  
Noise Levels ◽  
Thermally Activated ◽  
Mass Resolving Power

AbstractThe effects of varying the pulse energy of a picosecond laser used in the pulsed-laser atom-probe (PLAP) tomography of an as-quenched Ni-6.5 Al-9.5 Cr at.% alloy are assessed based on the quality of the mass spectra and the compositional accuracy of the technique. Compared to pulsed-voltage atom-probe tomography, PLAP tomography improves mass resolving power, decreases noise levels, and improves compositional accuracy. Experimental evidence suggests that Ni2+, Al2+, and Cr2+ ions are formed primarily by a thermally activated evaporation process, and not by post-ionization of the ions in the 1+ charge state. An analysis of the detected noise levels reveals that for properly chosen instrument parameters, there is no significant steady-state heating of the Ni-6.5 Al-9.5 Cr at.% tips during PLAP tomography.

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