Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 01 processing: Difference between revisions
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==Flat alignment== | ==Flat alignment== | ||
At the end of the substrate detection, the sample is scanned twice along the flat, in order to determine the substrate rotation. This angle will be presented in the exposure panel along with the option to expose the design rotated in order to compensate for this angle, i.e. aligned to the flat. | At the end of the substrate detection, the sample is scanned twice along the flat, in order to determine the substrate rotation. This angle will be presented in the exposure panel along with the option to expose the design rotated in order to compensate for this angle, i.e. aligned to the flat. | ||
<br/>The flat alignment accuracy has been measured to be 0±0.1° quite consistently. Out of a total of 13 exposures, only were misaligned by more than 0.1° | <br/>The flat alignment accuracy has been measured to be 0±0.1° quite consistently. Out of a total of 13 exposures, only two were misaligned by more than 0.1° | ||
=Alignment= | =Alignment= | ||
Revision as of 16:02, 18 December 2017
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Process Parameters
Exposure dose
The exposure dose needed inn the Aligner: Maskless 01 seems to follow the dose needed to process the same substrate in KS Aligner. As doses get higher, there is a tendency for the dose needed in the Aligner: Maskless 01 to exceed the dose needed in KS Aligner.
Defocus
The optimal defocus setting is probable a function of the resist thickness, but for 1.5µm resist, a defocus of -4 seems to be optimal.
Substrate positionning
During load, the machine will focus on the surface of the sample. Then, using the pneumatic focusing mechanism, it will detect the edges of the sample (dependent on the substrate template used) in order to determine the center of the sample. The following results rapport findings using the "4 inch wafer" template on a standard 100mm Si substrate.
Substrate centering
During the substrate detection, the sample is scanned along the x- and Y-axes, as well as diagonally. From these measurements, the diameter of the substrate is calculated, as well as the stage position matching the center of the substrate. This stage position will be the default origin for the subsequent exposure.
Unfortunately, the centering does not compensate for major or minor flats. The center position will therefor typically be displaced several mm from the center of the substrate along the Y-axis due to the major flat, and possibly also shifted due to any minor flats. These shifts have successfully been compensated during file conversion, in order to give a centering accuracy of ±200µm.
Flat alignment
At the end of the substrate detection, the sample is scanned twice along the flat, in order to determine the substrate rotation. This angle will be presented in the exposure panel along with the option to expose the design rotated in order to compensate for this angle, i.e. aligned to the flat.
The flat alignment accuracy has been measured to be 0±0.1° quite consistently. Out of a total of 13 exposures, only two were misaligned by more than 0.1°