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Unformatted text preview: Homework set 1 Solutions 1. The three components of photoresist are: the resin, solvent and photoactive compound. The resist is bakes after spinning primarily to remove any remaining solvents. 2. (a) The width and spacing of the developed resist structures would be 0.5 m. (b) If the exposure time and therefore the dose is reduced by 10%, the width of the sine wave pattern at the threshold dose for exposure is reduced. This width can be derived by solving for the values of xt there the dose equals the threshold for exposure (1.0 = 0.9 [sin2xt +1.0]). The width of the exposed pattern where the positive resist will be developed and removed is 0.46m leaving 0.54m resist widths. Please note that the exposed positive resist is removed while exposed negative resist remains after development. 3. Non linear optical lithography uses a process that requires the energy or two or more photons to expose the resist. The effective dose pattern therefore depends on higher than powers of the intensity and the effects of diffraction can be reduced to yield better resolution. 4. Electron scattering limits electron beam lithography, lens imperfections can also limit the spot size but the ultimate limit is the spread of exposing energy due to the scattering of the electrons. 5. Any source for evaporation, sputtering, laser ablation etc would be an acceptable answer. ...
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This note was uploaded on 09/27/2010 for the course A&EP 1200 taught by Professor Perez during the Spring '08 term at Cornell University (Engineering School).
- Spring '08