Excimer Laser Micromachining of Silicon and On-Line Machining Depth Discovery Using Laser Interferometry

2000 ◽  
Author(s):  
Senthil Theppakuttai ◽  
Shaochen Chen
Keyword(s):  
Excimer Laser ◽  
Wave Length ◽  
Michelson Interferometer ◽  
Surface Profile ◽  
Laser Micromachining ◽  
Optical Microscope ◽  
In Situ Monitoring ◽  
Depth Information ◽  
Profile Measurement

Abstract In this paper a parametric study on the excimer laser micromachining of silicon (Si) is conducted and a Michelson interferometer is used for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. An excimer laser of wave length 308 nm is used for the micromachining process. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer and the setup consists of a beam splitter, beam expander and other optics. The interference patterns caused due to the change in the path length between the two interferometer arms gives the machined depth information. These interference patterns are captured by using a photodiode and an oscilloscope. Results from the interferometer are compared with the actual depth measurements obtained by using a surface profilometer in combination with an optical microscope. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer measurements with a very high accuracy. The experimental results demonstrate the feasibility of applying this system for the in-situ monitoring of the micromachining process.

scholarly journals In-Situ Monitoring and Analysis of the Pitting Corrosion of Carbon Steel by Acoustic Emission

2019 ◽  
Vol 9 (4) ◽  
pp. 706 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and corrosion morphology in-situ capturing using an optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with a scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After completion of the signal processing, including pre-treatment, shape preserving interpolation, and denoising, for raw AE waveforms, three types of AE signals were classified in the correlation diagrams of the new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

Uniaxial High-Speed Micro-Scale Three-Dimensional Surface Topographical Measurements Using Fringe Projection

2020 ◽  
Author(s):  
Yi Zheng ◽  
Beiwen Li
Keyword(s):  
High Speed ◽  
Sample Surface ◽  
3D Scanning ◽  
In Situ Monitoring ◽  
Fringe Projection ◽  
Depth Information ◽  
Projection Technique ◽  
Projection System ◽  
Loop Control

Abstract In-situ inspection has drawn many attentions in manufacturing due to the importance of quality assurance. Having an accurate and robust in-situ monitoring can assist corrective actions for a closed-loop control of a manufacturing process. The fringe projection technique, as a variation of the structured light technique, has demonstrated significant potential for real-time in-situ monitoring and inspection given its merits of conducting simultaneous high-speed and high accuracy measurements. However, high-speed 3D scanning methods like fringe projection technique are typically based on triangulation principle, meaning that the depth information is retrieved by analyzing the triangulation relationship between the light emitter (i.e., projector), the image receiver (i.e., camera) and the tested sample surface. Such measurement scheme cannot reconstruct 3D surfaces where large geometrical variations are present, such as a deep-hole or a stair geometry. This is because large geometrical variations will block the auxiliary light used in the triangulation based methods, which will resultantly cause a shadowed area to occur. In this paper, we propose a uniaxial fringe projection technique to address such limitation. We measured a stair model using both conventional triangulation-based fringe projection technique and the proposed method for comparison. Our experiment demonstrates that the proposed uniaxial fringe projection technique can perform high-speed 3D scanning without shadows appearing in the scene. Quantitative testing shows that an accuracy of 1.15% can be obtained using the proposed uniaxial fringe projection system.

scholarly journals In-Situ Monitoring and Analyzing Pitting Corrosion of Carbon Steel by Acoustic Emission

2018 ◽  
Author(s):  
Junlei Tang ◽  
Junyang Li ◽  
Hu Wang ◽  
Yingying Wang ◽  
Geng Chen
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Pitting Corrosion ◽  
Optical Microscope ◽  
Open Circuit ◽  
In Situ Monitoring ◽  
Localized Corrosion ◽  
Uniform Corrosion ◽  
Corrosion Morphology

The acoustic emission (AE) technique was applied to monitor the pitting corrosion of carbon steel in NaHCO3 + NaCl solutions. The open circuit potential (OCP) measurement and the corrosion morphology in-situ capturing using optical microscope were conducted during AE monitoring. The corrosion micromorphology was characterized with scanning electron microscope (SEM). The propagation behavior and AE features of natural pitting on carbon steel were investigated. After the performing of signal processing including pre-treatment, shape preserving interpolation and denoising for raw AE waveforms, three types of AE signals can be classified in the correlation diagrams of new waveform parameters. Finally, a 2D pattern recognition method was established to calculate the similarity of different continuous AE graphics, which is quite effective to distinguish the localized corrosion from uniform corrosion.

Integrated Multi-Sensor Tribo-SPM Nano+Micro Tribo-Metrology

2005 ◽  
Author(s):  
Norm Gitis ◽  
Antanas Daugela ◽  
Jun Xiao ◽  
Michael Vinogradov
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Optical Microscope ◽  
In Situ Monitoring ◽  
Nano Indentation ◽  
Solid Thin Films

A novel quantitative nano+micro tribometer with integrated AFM and optical microscope has been utilized to characterize tribological and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests.

scholarly journals In-situ fiber-based surface profile measurement system using low coherence interferometer

2018 ◽  
Author(s):  
Jon Petzing ◽  
Shreedhar Rangappa ◽  
Peter Kinnell ◽  
Ranveer S. Matharu ◽  
Tom Hovell ◽  
...  
Keyword(s):  
Measurement System ◽  
Surface Profile ◽  
Profile Measurement ◽  
Low Coherence ◽  
Surface Profile Measurement

Progress toward excimer laser metal planarization and via hole filling using in-situ monitoring

1993 ◽  
Vol 20 (1-2) ◽  
pp. 89-106 ◽  
Author(s):  
Paul G. Carey ◽  
Bertram J. Woratschek ◽  
Friedrich Bachmann
Keyword(s):  
Excimer Laser ◽  
In Situ Monitoring ◽  
Hole Filling ◽  
Via Hole

In-Situ Quantitative Integrated Tribo-SPM Nano-Micro-Metrology

2004 ◽  
Author(s):  
Norm Gitis ◽  
Antanas Daugela ◽  
Arun Sikder ◽  
Michael Vinogradov ◽  
Alex Meyman
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Optical Microscope ◽  
In Situ Monitoring ◽  
Materials Properties ◽  
Nano Indentation ◽  
Solid Thin Films ◽  
Microscope Imaging

A novel quantitative nano/micro-tribometer with integrated SPM and optical microscope imaging has been developed to characterize numerous physical and mechanical properties of liquid and solid thin films and coatings, with in-situ monitoring their changes during micro and nano indentation, scratching, reciprocating, rotating and other tribology tests. Both the materials properties and surface topography can be assessed periodically during the tests.

Uniaxial High-Speed Micro-Scale 3D Surface Topographical Measurements Using Fringe Projection

2020 ◽  
Author(s):  
Yi Zheng ◽  
Beiwen Li
Keyword(s):  
Real Time ◽  
High Speed ◽  
Structured Light ◽  
3D Scanning ◽  
In Situ Monitoring ◽  
Physical Contact ◽  
Fringe Projection ◽  
Depth Information ◽  
Projection Technique

Abstract In-situ inspection has drawn many attentions in manufacturing due to the importance of quality assurance. With the rapid growth of additive manufacturing technology, the importance of in-line/in-situ inspections has been raised to a higher level due to many uncertainties that could occur during an additive printing process. Given this, having accurate and robust in-situ monitoring can assist corrective actions for a closed-loop control of a manufacturing process. Contact 3D profilometers such as stylus profilometers or coordinate measuring machines can achieve very high accuracies. However, due to the requirement for physical contact, such methods have limited measurement speeds and may cause damage to the tested surface. Thus, contact methods are not quite suitable for real-time in-situ metrology. Non-contact methods include both passive and active methods. Passive methods (e.g., focus variation or stereo vision) hinges on image-based depth analysis, yet the accuracies of passive methods may be impacted by light conditions of the environment and the texture quality of the surface. Active 3D scanning methods such as laser scanning or structured light are suitable for instant quality inspection due to their ability to conduct a quick non-contact 3D scan of the entire surface of a workpiece. Specifically, the fringe projection technique, as a variation of the structured light technique, has demonstrated significant potential for real-time in-situ monitoring and inspection given its merits of conducting simultaneous high-speed (from 30 Hz real-time to kilohertz high speeds) and high accuracy (tens of μm) measurements. However, high-speed 3D scanning methods like fringe projection technique are typically based on triangulation principle, meaning that the depth information is retrieved by analyzing the triangulation relationship between the light emitter (i.e., projector), the image receiver (i.e., camera) and the tested sample surface. Such measurement scheme cannot reconstruct 3D surfaces where large geometrical variations are present, such as a deep-hole or a stair geometry. This is because large geometrical variations will block the auxiliary light used in the triangulation based methods, which will resultantly cause a shadowed area to occur. In this paper, we propose a uniaxial fringe projection technique to address such limitation. We measured a stair model using both conventional triangulation based fringe projection technique and the proposed method for comparison. Our experiment demonstrates that the proposed uniaxial fringe projection technique can perform high-speed 3D scanning without shadows appearing in the scene. Quantitative testing shows that an accuracy of 35 μm can be obtained by measuring a step-height object using the proposed uniaxial fringe projection system.

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