| Autor: |
Douglas S. Goodman, J. Chastang, C. Surovic, N. Bobroff, R. Rand, J.S. Wilczynski, P. Fadi, Fuad E. Doany, A.E. Rosenbluth, R. Singh, S. Lovas, R. Myer, T. Ainsworth |
| Rok vydání: |
1991 |
| Předmět: |
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| Zdroj: |
Optical Society of America Annual Meeting. |
| DOI: |
10.1364/oam.1991.fy6 |
| Popis: |
A large-field scanning imaging system has been developed to perform imaging ablation with a 308-nm XeCl excimer laser as the sources. A 1× Dyson-type lens with a 12-mm field images a portion of a mask onto the part to be ablated. The numerical aperture is 0.05, so patterns as small as 6 µm can be formed. A plane mirror and a roof mirror are combined so that the object and image planes are parallel and their orientations are identical. The mask and part are held on a common stage, which moves in a boustrophedonic manner to transfer the entire pattern. The stage travel allows for parts as large as 250 × 250 mm2. The illuminated region is diamond-shaped, and adjacent scans overlap by half its width to obtain uniformity. The illumination system includes a hollow four-sided kaleidoscope to provide uniformity. Scanning further increases the uniformity by averaging over the field of the lens in one direction. Alignment is performed by optically combining images of mask marks and part marks formed by two pairs of microscope objectives, one of each viewing the part and the other viewing the mask. The illumination of the mask and part alignment marks can be independently optimized. Presently, the part is illuminated in darkfield reflected light and the mask with brightfield transmitted light. Registration to 1µm has been achieved over a region of 127 × 127 mm2. Focus is found with the alignment optics, whose numerical aperture is 0.4, giving it a depth of focus much less than that of the ablation lens. The part is levelled, focused, and registered relative to the image of the mask by a motion system with 6° of freedom that is mounted on the scanning stage. The excimer laser produces 300 W at 150 shots per second. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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