Comments for One Stop Micro http://onestopmicro.com Laser Micromachining...and more... Thu, 28 Jan 2010 20:06:05 -0500 http://wordpress.org/?v=2.8.4 hourly 1 Comment on Superstitious Pigeons and Laser Micromachining by Dana Church http://onestopmicro.com/superstitious-pigeons-and-laser-micromachining/comment-page-1/#comment-410 Dana Church Thu, 28 Jan 2010 20:06:05 +0000 http://onestopmicro.com/?p=42#comment-410 Amen!!! Amen!!!

]]> Comment on Post-fab visualization: the deceptiveness of SEM pictures by admin http://onestopmicro.com/post-fab-visualization-the-deceptiveness-of-sem-pictures/comment-page-1/#comment-335 admin Fri, 12 Jun 2009 04:56:33 +0000 http://onestopmicro.com/?p=40#comment-335 I am not sure if you had a question, and so have been too lazy to comment on this. Apologies. The theoretical resolution of a 157nm is much smaller than 5 microns. In fact, we routinely achieve this using 193nm lasers. For example, in the area of diamond marking, where the character sizes are as small as 50 microns, the spot size is often smaller than 2 microns. Of course, there is a difference between spot size and feature size... White light interferometry does NOT give you much horizontal resolution, that is, resolution as understood in the world of optical microscopy. Resolution here is determined by the RST's objective's NA and the wavelength of light (in this case an average for white light), just like it is in traditional optical microscopy. The resolution for a White light interferometer comes from the very high resolution of piezo material while scanning vertically, and the very short depth within which interference patterns appear and disappear when using white light. The RSTs I worked with used 2 types of measurement methods: VSI (vertical scanning interferometry) and PSI (phase shifting interferomtry). VSI has a much higher reolution, and uses fringe modulation information while scanning vertically. PSI uses fringe intensity information while making just a few steps of vertical motion. In my several years of working with SEMs and RSTs as micrometrology tools for laser micromachining, I have found RSTs to provide only superficial information that is fit only for publications with fancy bar graphs and surface plots. Sorry for the cynicism. SEMs on the other hand don't do much to help process engineers in their day to day laser micromachining work. They are, again, good for publications. Also excellent for investor relations :) Nothing beats a good old Optical Microscopy setup with good lighting, good reticles, and extra long working distance :) PS: While at it, can I also rubbish the misleading claims of RST makers of providing Angstrom level resolution... Edit: I re-read the article and realized I had written 200 microns instead of 2 microns. Now I understand what you meant...Sorry! I am not sure if you had a question, and so have been too lazy to comment on this. Apologies.
The theoretical resolution of a 157nm is much smaller than 5 microns. In fact, we routinely achieve this using 193nm lasers. For example, in the area of diamond marking, where the character sizes are as small as 50 microns, the spot size is often smaller than 2 microns. Of course, there is a difference between spot size and feature size…
White light interferometry does NOT give you much horizontal resolution, that is, resolution as understood in the world of optical microscopy. Resolution here is determined by the RST’s objective’s NA and the wavelength of light (in this case an average for white light), just like it is in traditional optical microscopy.
The resolution for a White light interferometer comes from the very high resolution of piezo material while scanning vertically, and the very short depth within which interference patterns appear and disappear when using white light.
The RSTs I worked with used 2 types of measurement methods: VSI (vertical scanning interferometry) and PSI (phase shifting interferomtry). VSI has a much higher reolution, and uses fringe modulation information while scanning vertically. PSI uses fringe intensity information while making just a few steps of vertical motion.
In my several years of working with SEMs and RSTs as micrometrology tools for laser micromachining, I have found RSTs to provide only superficial information that is fit only for publications with fancy bar graphs and surface plots. Sorry for the cynicism.
SEMs on the other hand don’t do much to help process engineers in their day to day laser micromachining work. They are, again, good for publications. Also excellent for investor relations :)
Nothing beats a good old Optical Microscopy setup with good lighting, good reticles, and extra long working distance :)
PS: While at it, can I also rubbish the misleading claims of RST makers of providing Angstrom level resolution…
Edit: I re-read the article and realized I had written 200 microns instead of 2 microns. Now I understand what you meant…Sorry!

]]> Comment on What type is your Laser Micromachining project? by admin http://onestopmicro.com/what-type-is-your-laser-micromachining-project/comment-page-1/#comment-332 admin Mon, 01 Jun 2009 04:01:00 +0000 http://onestopmicro.com/?p=10#comment-332 "I am searchining for a laser micromachining project that must be executed only by employing an indusrial robot arm ( by addapting the laser head on the robot arm)" I am not sure I understand: 1)Are you looking for a project for which you already have a Robot Arm mounted laser system? 2)Or do you already have a project and are you looking for a solution to your need where the laser head is mounted on the Robot? Is it a micromachining application? Or an industrial welding/cutting (Automobile type) application? “I am searchining for a laser micromachining project that must be executed only by employing an indusrial robot arm ( by addapting the laser head on the robot arm)”

I am not sure I understand:
1)Are you looking for a project for which you already have a Robot Arm mounted laser system?
2)Or do you already have a project and are you looking for a solution to your need where the laser head is mounted on the Robot?

Is it a micromachining application? Or an industrial welding/cutting (Automobile type) application?

]]> Comment on What type is your Laser Micromachining project? by Thaier http://onestopmicro.com/what-type-is-your-laser-micromachining-project/comment-page-1/#comment-331 Thaier Fri, 29 May 2009 17:32:08 +0000 http://onestopmicro.com/?p=10#comment-331 Hi I am searchining for a laser micromachining project that must be executed only by employing an indusrial robot arm ( by addapting the laser head on the robot arm) Hi
I am searchining for a laser micromachining project that must be executed only by employing an indusrial robot arm ( by addapting the laser head on the robot arm)

]]> Comment on And when I get that feeling, I want Micromachining by Jayjay http://onestopmicro.com/and-when-i-get-that-feeling-i-want-micromachining/comment-page-1/#comment-313 Jayjay Tue, 26 May 2009 15:01:20 +0000 http://onestopmicro.com/?p=46#comment-313 Super! Micro Machining Healing :) Super! Micro Machining Healing :)

]]> Comment on Post-fab visualization: the deceptiveness of SEM pictures by Sendhil, RRCAT http://onestopmicro.com/post-fab-visualization-the-deceptiveness-of-sem-pictures/comment-page-1/#comment-249 Sendhil, RRCAT Tue, 28 Apr 2009 09:03:51 +0000 http://onestopmicro.com/?p=40#comment-249 One can get down to 5 micron features or smaller when using 157nm of Fluorine Excimer Laser for micromaching. White light interferometers (a mirau on a induatrial micrscope) kind of gives the best of both SEM and optical microscopy. One gets an extended depth of focus due to axial scanning and since the Z can be encoded 3D reconstruction is possible. One can get down to 5 micron features or smaller when using 157nm of Fluorine Excimer Laser for micromaching. White light interferometers (a mirau on a induatrial micrscope) kind of gives the best of both SEM and optical microscopy. One gets an extended depth of focus due to axial scanning and since the Z can be encoded 3D reconstruction is possible.

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