MLA 150 (DLA)
Presentation and examples
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Presentation of the tool
The MLA 150 (named DLA in the past) is a new generation Maskless Aligner developed by Heidelberg
Instruments GmbH in Germany.
It has been installed at EPFL to test its capabilities. It is free of charge for the users who complete the
feedback document (available on cmi website, under the description of the tool). All images and results
are always welcome.
This system allows researcher to quickly write a design on a wafer, without the need to order or
produce a mask. Once the design is done, the MLA can read, align and expose it on a substrate within
a few minutes.
The system is equipped with:
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Exposure source: 405 nm laser diode
3 cameras: overview for quick crosses localization, macro and micro for automatic detection
of alignment crosses
Real time autofocus
Stage system, position control with interferometers, chuck with vacuum for various substrate
sizes
And offers the following specifications:
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Minimum feature size: 1 um
Uniformity: <100 nm
Alignment accuracy: <500 nm (down to <200 nm depending to the size of the design)
Maximum substrate size: 220 mm x 220 mm (9’’x9’’)
Maximum exposure area: 150 mm x 150 mm
Designs compatibility: cif, gdsii, dxf, gerber
The system offers two writing speed with the following exposure time. (The exposure time may vary
depending on the complexity of your design)
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30 minutes for a full wafer in quality mode
15 minutes in fast mode
A dropbox, user manual, resist table and more information can be found on the PC of the MLA and on
the CMI website:
cmipc114/@public/documentation
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Exposure
The tool is equipped with a 405 nm laser diode. The top of the resist is automatically detected. There
are then only two parameters to set:
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Dose: controls the dose [mJ/cm2]. Keep in mind that the dose is not exactly the same as with
a mask aligner
Defocus: defines where the focus is done. If set to zero, focus is done on top of the resist and
a positive defocus will shift the focus downwards inside the resist (range: -10..10, 10 being a
shift of 6 microns)
Please find in the following table dose and defocus parameters for several resists:
Resist
AZ 1512
AZ 1512
Thickness [um]
1.6
1.1
Substrate
silicon
silicon
AZ 9260
AZ 9260
4
10
silicon
silicon
160
300
2
3
1.4
1.8
AZ ECI
AZ ECI
AZ ECI
AZ ECI
AZ ECI
0.6
1
2
4
5
silicon
silicon
silicon
silicon
silicon
120
160
320
650
800
-2
-2
-2
-2
-2
1
1.2
1.4
1.4
1.5
nlof
Dose [mJ/cm2] Defocus CD [um]
130
-2
2
90
-2
1.2
impossible
SU-8 alternative sensitive to a wave length of 405 nm (microresist.de)
mr-DWL
40
silicon
250 – 350
0 – 10
mr-DWL
80
silicon
300 – 400
0 – 10
2
3
If you want to try other resists, other substrates or thicknesses, an automated dose test with various
doses and focuses can be done in several minutes.
Alignment capabilities
If you want to perform an alignment with the MLA, you need to have 2 to 4 crosses on your design and
you need to know the coordinates of those crosses in the coordinate system of your design. The MLA
detects the center of the crosses. The design to be exposed is then centered and rotated to match the
coordinates of the crosses. For example, standard CMI crosses for the mask aligner have the following
coordinates: (-42000, 0) and (42000, 0) [um]
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Examples AZ 1512
Figure 1: AZ 1512, 1.1 um thick, 2 um checkerboard
Figure 2: AZ 1512, 1.1 um thick, pillars and holes with a diameter of 4 um
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 3: AZ 1512, 1.6 um thick, test structure
Examples AZ 9260
Figure 4: AZ 9260, 10um thick, 4 um pillars
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 5: AZ 9260, 10um thick, 4 um and 2 um lines and spaces
Examples AZ ECI
Figure 6: AZ ECI, 0.6 um thick, 1 um space, 1.5 um resist lines
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 7: AZ ECI, 0.6 um thick, 1.5 um pillars with 1 um space
Figure 8: AZ ECI, 5 um thick, 2 um lines and spaces
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 9: AZ ECI, 5 um thick, 4 um lines and spaces
Figure 10: 100 nm gold line fabricated with a double patterning using AZ ECI 0.6um. Gold was etched
with IBE. The first layer containing periodic 1 um lines and spaces was first exposed and etched with
IBE. The second layer containing the same periodic 1 um resist lines and spaces but with 100nm
overlap was then aligned and exposed.
Gold lines are thus the result of the overlap of two different layers aligned with the MLA. Figure 10
shows the uniformity of exposure and the alignment capabilities.
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 11: AZ ECI, 0.6 um thick, horizontal 1 um lines and spaces
Figure 12: AZ ECI, 0.6 um thick, vertical 1 um lines and spaces
It is worth mentioning that overexposition is slightly higher in the vertical direction.
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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mr-DWL 40 (SU-8 alternative sensitive to 405 nm)
This is an epoxy based negative photoresist developed by Microresist Technology GmbH in Berlin
(microresist.de) for direct laser writing at 405 nm.
Figure 13: mr-DWL 40, 80 um thick, cylinders
Figure 14: mr-DWL 40, 80 um thick, 1-7 um lines (1 and 2 um lines delaminated)
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 15: mr-DWL 40, 80 um thick. It is possible to play with the focus to change the sidewalls of the
exposed resist, in this case, the focus is 15 um downwards inside the resist
Figure 16: mr-DWL 40, 40 um thick, 20 um pillars array
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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Figure 17: mr-DWL 40, 40 um thick, 20 um square pillars obtained with two different focuses.
Figure 18: mr-DWL 40, 80 um thick, microfluidic mixer
Théophane Besson, 17.03.2015, Heidelberg Instruments GmbH
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