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Unformatted text preview: EE 215 Spring 06 Homework #1 Solutions 1) As you read the two articles by Feynman, which are available in the reference section of our course website, make a list of his predictions for microsystems. What did he get right? What did he get wrong? Some predictions that Feynman got right: • There is no question that if the thing were reduced by 25,000 times in the form of raised letters on the pin, it would be easy for us to read it today. Furthermore; there is no question that we would find it easy to make copies of the master; we would just need to press the same metal plate again into plastic and we would have another copy. o This is very similar to a technique that is now used called “Nanoimprint Lithography”. If you are interested in finding out more about this, type “NanoImprint Lithography” into Google. If you go to the advanced settings on Google you can set the file format to pdf and you will get a number of papers on this topic. Alternatively, you can specify the file format in the search term: “NanoImprint Lithography filetype:pdf” • The next question is: How do we write it? We have no standard technique to do this now. But let me argue that it is not as difficult as it first appears to be. We can reverse the lenses of the electron microscope in order to demagnify as well as magnify. A source of ions, sent through the microscope lenses in reverse, could be focused to a very small spot. We could write with that spot like we write in a TV cathode ray oscilloscope, by going across in lines, and having an adjustment which determines the amount of material which is going to be deposited as we scan in lines. o This technique is similar to a technique that is now used called “Focused Ion Beam” writing. Again, if you type “Focused Ion Beam filetype:pdf” into Google you will get many hits. By now you should get the message that Google is a powerful tool for searching for reference materials! • A simpler way might be this (though I am not sure it would work): We take light and, through an optical microscope running backwards, we focus it onto a very small photoelectric screen. Then electrons come away from the screen where the light is shining. These electrons are focused down in size by the electron microscope lenses to impinge directly upon the surface of the metal. Will such a beam etch away the metal if it is run long enough? I don't know. If it doesn't work for a metal surface, it must be possible to find some surface with which to coat the original pin so that, where the electrons bombard, a change is made which we could recognize later. o This technique is similar to a modern day technique called “E-Beam Lithography”. While we do not use a photoelectric screen, we do use an electron beam generated from a hot filament. The electrons are focused EE 215 Spring 06 Homework #1 Solutions with lenses down to a small spot by lenses as are used in an electron microscope, and scanned like a “TV cathode ray oscilloscope”.microscope, and scanned like a “TV cathode ray oscilloscope”....
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- Fall '05
- Electron, Nanoimprint lithography, characteristic length scale, Feynman, cathode ray oscilloscope, TV cathode ray