Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 04 processing: Difference between revisions
| (2 intermediate revisions by the same user not shown) | |||
| Line 1: | Line 1: | ||
<!-- | |||
<span style="background:#FF2800">THIS PAGE IS UNDER CONSTRUCTION</span>[[image:Under_construction.png|200px]] | <span style="background:#FF2800">THIS PAGE IS UNDER CONSTRUCTION</span>[[image:Under_construction.png|200px]] | ||
--> | |||
{{:Specific Process Knowledge/Lithography/authors_generic}} | {{:Specific Process Knowledge/Lithography/authors_generic}} | ||
| Line 11: | Line 12: | ||
=Exposure technology= | =Exposure technology= | ||
<!-- | |||
[[Image:section under construction.jpg|70px]] | [[Image:section under construction.jpg|70px]] | ||
--> | |||
Aligner: Maskless 04 is both a direct writer and not a direct laser writer. In Raster mode, it works like | Aligner: Maskless 04 is both a direct laser writer and not a direct laser writer. In Raster mode, it works like MLA1, where an image is projected onto the substrate surface, and stepped across the substrate in order to produce the entire pattern. In Vector mode, it is a direct laser writer, where a focused laser beam is moved across the substrate surface in order to trace out the pattern. | ||
The writing head of the Aligner: Maskless 04 moves only in the z-direction. Using a focusing system, 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 04 moves only in the z-direction. Using a focusing system, 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. | ||
| Line 26: | Line 28: | ||
=Process Parameters= | =Process Parameters= | ||
<!-- | |||
[[Image:section under construction.jpg|70px]] | [[Image:section under construction.jpg|70px]] | ||
--> | |||
Control of the exposure dose differs between the two available exposure modes. In Raster mode, the dose is directly controlled by the on-time of the DMD mirrors during exposure, and the dose process parameter is thus simply given in units of mJ/cm<sup>2</sup>. As the intensity of the exposure light at the substrate surface cannot easily be measured, this dose is indirectly calibrated at the factory, by adjusting the optimal dose to match the known dose of a particular resist. | Control of the exposure dose differs between the two available exposure modes. In Raster mode, the dose is directly controlled by the on-time of the DMD mirrors during exposure, and the dose process parameter is thus simply given in units of mJ/cm<sup>2</sup>. As the intensity of the exposure light at the substrate surface cannot easily be measured, this dose is indirectly calibrated at the factory, by adjusting the optimal dose to match the known dose of a particular resist. | ||
| Line 35: | Line 38: | ||
*Laser Power [0-120 mW]; the output power of the diode laser | *Laser Power [0-120 mW]; the output power of the diode laser | ||
*Exposure Velocity [0-200 mm/s]; the movement speed of the stage during exposure | *Exposure Velocity [0-200 mm/s]; the movement speed of the stage during exposure | ||
The Pen determines the size of the spot on the substrate surface and thus the ultimate resolution. It may also affect the intensity available at the substrate. For highly sensitive resists, the Transmission can be used to limit the available intensity at the substrate (lowering the required Exposure Velocity | The Pen determines the size of the spot on the substrate surface and thus the ultimate resolution. It may also affect the intensity available at the substrate. For highly sensitive resists, the Transmission can be used to limit the available intensity at the substrate (lowering the required Exposure Velocity to a more reasonable value). The Laser Power directly affects the intensity available at the substrate. The Exposure Velocity determines the dwell time at each point on the substrate, and thus the effective dose received by the resist at the intensity determined by the three other parameters. | ||
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. The "defoc" parameter us a unitless value, representing ±100% of the available correction available above and below the initial focus point established during loading of the substrate. One defoc step is approximately 0.25µm. Positive defoc is into the resist, i.e. writehead moves down when defoc is increased. | 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. The "defoc" parameter us a unitless value, representing ±100% of the available correction available above and below the initial focus point established during loading of the substrate. One defoc step is approximately 0.25µm. Positive defoc is into the resist, i.e. writehead moves down when defoc is increased. | ||
| Line 184: | Line 187: | ||
=Substrate positioning= | =Substrate positioning= | ||
<!-- | |||
[[Image:section under construction.jpg|70px]] | [[Image:section under construction.jpg|70px]] | ||
--> | |||
During load, the machine will focus on the surface of the sample. Then, using the automatic focusing system, it will detect the edges of the sample (this function depends on the substrate template used) in order to determine the center and rotation of the sample. The following results rapport findings using the "Wafer (d=100 mm; Flat)" template on a standard 100mm Si substrate. | During load, the machine will focus on the surface of the sample. Then, using the automatic focusing system, it will detect the edges of the sample (this function depends on the substrate template used) in order to determine the center and rotation of the sample. The following results rapport findings using the "Wafer (d=100 mm; Flat)" template on a standard 100mm Si substrate. | ||
| Line 200: | Line 204: | ||
=Alignment= | =Alignment= | ||
<!-- | |||
[[Image:section under construction.jpg|70px]] | [[Image:section under construction.jpg|70px]] | ||
--> | |||
The alignment accuracy of the Aligner: Maskless 04 is a combination of the position accuracy of the stage, the accuracy of the alignment mark detection, and the distortion of the pattern already on the wafer (first print). The alignment specification of the machine is 1µm for both raster and vector mode, which was demonstrated in the factory acceptance test and the site acceptance test after installation. | The alignment accuracy of the Aligner: Maskless 04 is a combination of the position accuracy of the stage, the accuracy of the alignment mark detection, and the distortion of the pattern already on the wafer (first print). The alignment specification of the machine is 1µm for both raster and vector mode, which was demonstrated in the factory acceptance test and the site acceptance test after installation. | ||
<br>An alignment test performed shortly after installation, using a 3x3 array of structures with 30mm pitch, showed an alignment error of 0.29±0.18µm in X and -0.49±0.23µm in Y (Raster mode). | <br>An alignment test performed shortly after installation, using a 3x3 array of structures with 30mm pitch, showed an alignment error of 0.29±0.18µm in X and -0.49±0.23µm in Y (Raster mode). | ||