Specific Process Knowledge/Lithography/Aligners/Aligner: Maskless 02 processing - Revision history

Jehem at 11:23, 20 April 2026

2026-04-20T11:23:50Z

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	{{~~:Specific Process Knowledge/Lithography/authors_generic~~}}		{{cc-nanolab}}

	'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php?title=Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing click here]'''		'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php?title=Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing click here]'''

Taran at 14:23, 16 September 2025

2025-09-16T14:23:57Z

← Older revision		Revision as of 16:23, 16 September 2025
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	[[Category: Equipment\|Lithography]]		[[Category: Equipment\|Lithography]]
	[[Category: Lithography]]		[[Category: Lithography]]

	~~[[Image:DUV_wafers.jpg\|500px\|frameless\|right\|]]~~

	__TOC__		__TOC__
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	=Exposure technology=		=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, 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.		Aligner: Maskless 02 is ''not'' a direct laser 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 375 nm (2.8 W). The spatial 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 on and off, 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 stripes in order to expose the entire design. Each stripe is overlapping 2 or 5 times, depending on the chosen [[Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing#Exposure_mode\|exposure mode]]), in order to reduce 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 light source is a laser diode (array) with a wavelength of 375 nm (2.8 W). The spatial 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 on and off, 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 stripes in order to expose the entire design. Each stripe is overlapping 2 or 5 times, depending on the chosen [[Specific_Process_Knowledge/Lithography/Aligners/Aligner:_Maskless_02_processing#Exposure_mode\|exposure mode]]), in order to reduce 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.

Taran: /* Process Parameters */

2025-03-20T12:12:49Z

Process Parameters

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	The correct way to determine the best dose-defocus settings is to generate a so-called Bossung plot (known from projection lithography), which plots the printed linewidth as a function of dose and defocus. From this, the most stable region of parameter space is chosen, i.e. the region where the linewidth changes the least when dose and defocus changes. Any deviation from the design linewidth may be corrected using the CD bias parameter. This typically involves SEM imaging of resist cross-sections, and quickly becomes time-consuming. However, in most cases, inspection of a dose-defocus matrix (easily generated using the series exposure function) in an optical microscope will get you most of the way.		The correct way to determine the best dose-defocus settings is to generate a so-called Bossung plot (known from projection lithography), which plots the printed linewidth as a function of dose and defocus. From this, the most stable region of parameter space is chosen, i.e. the region where the linewidth changes the least when dose and defocus changes. Any deviation from the design linewidth may be corrected using the CD bias parameter. This typically involves SEM imaging of resist cross-sections, and quickly becomes time-consuming. However, in most cases, inspection of a dose-defocus matrix (easily generated using the series exposure function) in an optical microscope will get you most of the way.

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Jehem: /* Exposure dose and defocus */

2024-03-07T08:24:35Z

Exposure dose and defocus

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	'''Pneumatic:'''		'''Pneumatic:'''

	Substrates must be at least 5x5 mm to be successfully loaded. The pneumatic AF freezes at a distance of 3 mm form the substrate edge, which means that in order to have any ''dynamic'' focusing, using the pneumatic AF, the substrate must be larger than 6x6 mm.		Substrates must be at least 5x5 mm to be successfully loaded. The pneumatic AF freezes at a distance of 3 mm form the substrate edge, which means that in order to have any ''dynamic'' focusing, using the pneumatic AF, the substrate must be larger than 6x6 mm. When using the pneumatic autofocus, we recommend a substrate size of at least 20x20 mm.

	==Exposure mode==		==Exposure mode==

Taran: /* Process Parameters */

2023-11-19T23:22:35Z

Process Parameters

← Older revision		Revision as of 01:22, 20 November 2023
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	==~~Defocus~~==		==Exposure dose and defocus==
			[[Specific Process Knowledge/Lithography/Resist#Aligner:_Maskless_02\|Information on UV exposure dose]]

	Aligner: Maskless 02 offers two autofocus modes; optical or pneumatic. The autofocus mode is selected via the substrate template. 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 02 offers two autofocus modes; optical or pneumatic. The autofocus mode is selected via the substrate template. 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.

Jehem: /* Alignment */

2023-09-26T09:03:32Z

Alignment

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	=Alignment=		=Alignment=
	~~<span style="color:red">New specs after the new writehead has been installed - section will be updated soon.</span>~~

	'''Important information regarding alignment:'''		'''Important information regarding alignment:'''

Jehem: /* Advanced Field alignment (TSA) */

2023-09-26T09:00:50Z

Advanced Field alignment (TSA)

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	==Advanced Field alignment (TSA)==		==Advanced Field alignment (TSA)==
	~~<!--~~
	~~<span style="color:red">New specs after the new writehead has been installed - section will be updated soon.</span>~~
	~~-->~~

	'''Overlay accuracy (spec):''' 0.25 µm (5x5 mm<sup>2</sup> area)		'''Overlay accuracy (spec):''' 0.25 µm (5x5 mm<sup>2</sup> area)
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	\| 150 ±50		\| 150 ±50
	\| 128 ±50		\| 128 ±50

			<!--

	\|-		\|-
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	\| 0 ±50		\| 0 ±50
	\| 16 ±50		\| 16 ±50
			-->
	\|}		\|}

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Jehem: /* Back Side Alignment */

2023-09-26T08:47:38Z

Back Side Alignment

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	==Back Side Alignment==		==Back Side Alignment==
	~~<span style="color:red">New specs after the new writehead has been installed - section will be updated soon.</span>~~

	'''Overlay accuracy (spec):''' ~~1.0~~ µm		'''Overlay accuracy (spec):''' ±1 µm

	'''BSA windows:''' along the X and Y axes, 10 mm wide x 46 mm long, starting 14.5 mm from the center.		'''BSA windows:''' along the X and Y axes, 10 mm wide x 46 mm long, starting 14.5 mm from the center.
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	\|-		\|-
	\|-style="background:WhiteSmoke; color:black"		\|-style="background:WhiteSmoke; color:black"
	\|rowspan="2" align="center"\|Align-~~flip180~~-align~~, 3 points~~ <br/> ~~375 nm~~		\|rowspan="2" align="center"\|Align - flip 180° - align<br>3 point average
	\|'''X'''		\|'''X'''
	\| -0.625 ±0.125		\| -0.625 ±0.125
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	\| -0.75 ±0.125		\| -0.75 ±0.125

			<!--
	\|-		\|-
	\|-style="background:WhiteSmoke; color:black"		\|-style="background:WhiteSmoke; color:black"
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	\|'''Y'''		\|'''Y'''
	\| 0.0 ±0.0		\| 0.0 ±0.0
			-->
	\|}		\|}

Jehem: /* Top Side Alignment */

2023-09-26T08:40:42Z

Top Side Alignment

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	-->		-->

	'''Overlay accuracy (spec):''' 0.~~5µm~~		'''Overlay accuracy (spec):''' ±0.5 µm

	'''Camera field of view (W x H):''' <br>		'''Camera field of view (W x H):''' <br>

Jehem: /* Top Side Alignment */

2023-09-26T08:39:41Z

Top Side Alignment

← Older revision		Revision as of 10:39, 26 September 2023
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	\| -6.1±2.5		\| -6.1±2.5
	\| -0.8±1.2		\| -0.8±1.2

			<!--

	\|-		\|-
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	\| 1.1±1.7		\| 1.1±1.7

			-->
	\|}		\|}

			<!--
	'''Alignment test with scaled first print'''		'''Alignment test with scaled first print'''
	{\|border="1" cellspacing="0" cellpadding="3" style="text-align:center;"		{\|border="1" cellspacing="0" cellpadding="3" style="text-align:center;"
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	\|}		\|}
			-->

	==Back Side Alignment==		==Back Side Alignment==