Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 02 processing: Difference between revisions

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 =Exposure technology=
-Aligner: Maskless 02 is not a direct writer. In the maskless aligner, the exposure light is passed through a spatial light modulator, much like in a video projector, and projected onto the substrate, thus exposing an area of the design at a time. The substrate is exposed by scanning the exposure field across the substrate in a succession of stripes.
+Aligner: Maskless 02 is ''not'' a direct writer. In the maskless aligner, the exposure light is passed through a spatial light modulator, much like in a video projector, and projected onto the substrate, exposing a small area of the design at a time. The substrate is fully exposed by scanning the exposure field across the substrate in a succession of exposure stripes.
-The light source is a laser diode (array) with a wavelength of 375nm (2.8W) or 405nm (8W) <span style="color:red">(July 2022: Using the 405 nm laser is not allowed)</span>. The spacial light modulator is a digital micro-mirror device. The individual mirrors of the DMD are switched in order to represent the design, and the laser is flashed in order to yield the desired exposure dose. This image is projected onto the substrate through a lens(system). The projected image yields a pixel size of 160nm X 160nm at wafer scale. The image is scanned across the substrate, in order to expose the entire design, each stripe overlapping (2 or 4 times depending on [[Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing#Exposure_mode|exposure mode]]) in order to minimize uniformity effects and stitching errors. The address grid size is 80nm or 40nm for Fast or High Quality exposure mode, respectively.
+The light source is a laser diode (array) with a wavelength of 375nm (2.8W). The spacial light modulator is a digital micro-mirror device. The individual mirrors of the DMD are switched on and off in order to represent the design, and the laser is flashed in order to give the desired exposure dose. The exposure image is projected onto the substrate through a lens (system). The projected image has a pixel size of 500x500 nm on the substrate surface. The image is scanned across the substrate, in order to expose the entire design, each stripe overlapping (2 or 5 times depending on [[Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing#Exposure_mode|exposure mode]]) in order to minimize light source non-uniformity effects and stitching errors. The address grid size is 250 nm or 100 nm for Fast and High Quality exposure mode, respectively.
-The writing head of the Aligner: Maskless 02 moves only in the z-direction. Using an optical, or pneumatic, focusing system <span style="color:red">(July 2022: The pneumatic AF has been disabled)</span>, the maskless aligner is able to do real-time autofocus. The defocus process parameter is used to compensate offsets in the focusing mechanism, and to optimize printing quality in different resists and varying thicknesses.
+The writing head of the Aligner: Maskless 02 moves only in the z-direction. Using the optical or pneumatic focusing system, the maskless aligner is able to do real-time dynamic autofocus. The defocus process parameter is used to offset the focusing mechanism, to optimize printing quality in different resists and resist thicknesses, as well as reflective or absorbing surfaces, and transparent or non-transparent substrates.
-The stage of the Aligner: Maskless 02 moves only in x and y. It has no theta-axis. All rotation during alignment is thus accomplished by transformation of the input design.
+The stage of the Aligner: Maskless 02 moves only in x and y. It has no theta-axis. All rotation during alignment is accomplished by digitally rotating the design to match the physical rotation of the substrate.
 =Process Parameters=