Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 04 processing: Difference between revisions
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Aligner: Maskless 04 offers not only two exposure modes, but also two autofocus modes; optical or pneumatic. The defocus process parameter is used to compensate for offsets between the autofocus mechanism and the focal point of the exposure light, and simultaneously optimize print quality in different resists and varying thicknesses. | Aligner: Maskless 04 offers not only two exposure modes, but also two autofocus modes; optical or pneumatic. The defocus process parameter is used to compensate for offsets between the autofocus mechanism and the focal point of the exposure light, and simultaneously optimize print quality in different resists and varying thicknesses. | ||
'''Optical:''' | '''Optical autofocus:''' Uses red laser light to focus on the substrate surface. Works for substrates down to 3x3 mm. | ||
Uses | '''Pneumatic autofocus:''' Uses compressed air flowing through the nozzle of the writehead to focus on the substrate surface. Substrates must be at least 5x5 mm to be successfully loaded. The pneumatic AF fails at some distance from the substrate edge, which means that in order to have any useful area in the center of the sample when using the pneumatic AF, the substrate must likely be larger than 5x5 mm. When using the pneumatic autofocus, we recommend a substrate size of at least 10x10 mm. | ||
''' | '''Raster mode''' | ||
'''Vector mode''' | |||
==Writing speed== | ==Writing speed== | ||
'''Raster mode''' | |||
[[Image:WritingSpeedVSAreaDose.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 04 as a function of the exposed area and the exposure dose]] | [[Image:WritingSpeedVSAreaDose.JPG|400x400px|thumb|The writing speed of Aligner: Maskless 04 as a function of the exposed area and the exposure dose]] | ||
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The exposure time increases linearly with exposure dose and writing area. However, due to the stepped nature of the exposure, the exposure time as a function of fill factor is highly nonlinear. It takes the same time to expose a single pixel as an entire 300µm X 400µm writing field, so the exposure time depends on the number of addressed writing fields, rather than on the fill factor of the design. In practice, there will probably not be much variation in exposure time with fill factor. Exposure tests using a 50mm<sup>2</sup> design have shown that the exposure time increases linearly from 40s at 10mJ/cm<sup>2</sup>, to 257s at 1000mJ/cm<sup>2</sup>. The fill factor of the design is 39%, but ~80% of the area is addressed by the writing fields. Scaled to a full 4" wafer, the exposure time is estimated to 2:37 hours at a dose of 100mJ/cm<sup>2</sup>. | The exposure time increases linearly with exposure dose and writing area. However, due to the stepped nature of the exposure, the exposure time as a function of fill factor is highly nonlinear. It takes the same time to expose a single pixel as an entire 300µm X 400µm writing field, so the exposure time depends on the number of addressed writing fields, rather than on the fill factor of the design. In practice, there will probably not be much variation in exposure time with fill factor. Exposure tests using a 50mm<sup>2</sup> design have shown that the exposure time increases linearly from 40s at 10mJ/cm<sup>2</sup>, to 257s at 1000mJ/cm<sup>2</sup>. The fill factor of the design is 39%, but ~80% of the area is addressed by the writing fields. Scaled to a full 4" wafer, the exposure time is estimated to 2:37 hours at a dose of 100mJ/cm<sup>2</sup>. | ||
<br clear="all" /> | <br clear="all" /> | ||
'''Vector mode''' | |||
==Resolution== | ==Resolution== | ||
'''Raster mode''' | |||
The pixel-size of the DMD in the Aligner: Maskless 01 is 0.5µm X 0.5µm (at the sample surface). The lithographic resolution of the machine is 1µm on paper, which was demonstrated in the acceptance test after installation using a resist thickness of 0.5µm. This result has later been confirmed. In 1.5µm thick resist, the resolution is around 2µm. | The pixel-size of the DMD in the Aligner: Maskless 01 is 0.5µm X 0.5µm (at the sample surface). The lithographic resolution of the machine is 1µm on paper, which was demonstrated in the acceptance test after installation using a resist thickness of 0.5µm. This result has later been confirmed. In 1.5µm thick resist, the resolution is around 2µm. | ||
'''Vector mode''' | |||
=Substrate positioning= | =Substrate positioning= | ||