Specific Process Knowledge/Lithography/UVExposure

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UV Exposure Comparison Table

Equipment		Aligner: MA6-1	Aligner: MA6-2	Aligner: Maskless 01	Aligner: Maskless 02	Aligner: Maskless 03	Aligner: Maskless 04
Purpose		Top Side Alignment Back Side Alignment UV exposure OBS: this tool is in PolyFabLab	Top Side Alignment Back Side Alignment UV exposure (DUV exposure) Bond alignment	Top Side Alignment Maskless UV exposure	Top Side Alignment Back Side Alignment Maskless UV exposure	Top Side Alignment Back Side Alignment Maskless UV exposure	Top Side Alignment Maskless UV exposure Direct laser writing OBS: this tool is in PolyFabLab
Performance	Minimum feature size	~1 µm	~1 µm	~1 µm	~1 µm	~1 µm	~1 µm
	Alignment accuracy	TSA: ±2 µm BSA: ±5 µm	TSA: ±1 µm BSA: ±2 µm	±2 µm (±1 µm possible)	TSA: ± 0.5 µm BSA: ± 1 µm	TSA: ± 0.5 µm BSA: ± 1 µm	±1 µm
	Exposure light	350W Hg lamp i-line filter (365nm bandpass filter)	500W Hg-Xe lamp i-line filter (365nm bandpass filter)	365nm LED	375nm laser diode array	405nm laser diode array	365nm LED 405nm laser diode
	Exposure mode	Flood exposure Proximity Contact: Soft contact Hard contact Vacuum contact	Flood exposure Proximity Contact: Soft contact Hard contact Vacuum contact	Projection: Pneumatic auto-focus	Projection: Optical auto-focus Pneumatic auto-focus	Projection: Pneumatic auto-focus	Projection: Optical auto-focus Pneumatic auto-focus Direct laser writing: Optical auto-focus Pneumatic auto-focus
Substrates	Batch size	1 100 mm wafer	1 small sample, down to 10x10 mm2 1 50 mm wafer 1 100 mm wafer 1 150 mm wafer	1 small sample, down to 5x5 mm2 1 50 mm wafer 1 100 mm wafer 1 150 mm wafer	1 small sample, down to 3x3 mm2 1 50 mm wafer 1 100 mm wafer 1 150 mm wafer 1 200 mm wafer	1 small sample, down to 5x5 mm2 1 50 mm wafer 1 100 mm wafer 1 150 mm wafer	1 small sample, down to 3x3 mm2 1 50 mm wafer 1 100 mm wafer 1 150 mm wafer
	Allowed materials	All PolyFabLab materials	All cleanroom materials except copper and steel Dedicated chuck for III-V materials	All cleanroom materials	All cleanroom materials	All cleanroom materials	All PolyFabLab materials

Aligner: MA6-1

The Aligner: MA6-1 is located in PolyFabLab.

Tool description
The Aligner: MA6-1 is a manual UV exposure system, which can be used for mask alignment and exposure of UV resists on 100 mm substrates. It is also capable of flood exposing chips, 50 mm and 150 mm substrates.

Product:	Süss mask aligner MA6
Year of purchase:	1999
Location:	PolyFabLab

User manual
The user manual and contact information can be found in LabManager - requires login

Tool training
Training on the tool requires users to complete the lithography TPT followed by reading the manual and watching the training videos. The tool authorization can be obtained after a successful hands-on authorization training session.

The training videos were made for MA6-2, but operation of MA6-1 is very similar as they are exactly the same model. Due to a different power supply, however, procedures for ignition and intensity control of the lamp is different for MA6-1. Please refer to the manual for the correct procedures.

Operation

Alignment

Equipment performance and process related parameters

Purpose	Mask alignment and UV exposure
Exposure modes	Vacuum contact Hard contact Soft contact Proximity Flood exposure
Exposure light/filters	365 nm (i-line) broadband (i-, g-, h-lines), requires tool change 303 nm, requires tool change
Minimum resolution	~1.25 µm
Mask size	5x5 inches
Alignment modes	Top side (TSA): ±2 µm Back side (BSA): ±5 µm
Substrate size	Mask exposure and alignment: 100 mm wafers Flood exposure: from samples to 150 mm wafers
Allowed materials	All PolyFabLab allowed materials
Substrate batch	1

Process information

The Aligner: MA6-1 has an i-line notch filter installed. This results in an exposure light peak around 365nm with a FWHM of 7nm.

Exposure dose

Information on UV exposure dose

Alignment mark design and locations

Alignment mark design and locations.

Aligner: MA6-2

The Aligner: MA6-2 is located in E-4.

Tool description
The Aligner: MA6-2 is a manual UV exposure system, which can be used for mask alignment and exposure of UV resists on chips, 50 mm, 100 mm, and 150 mm substrates.

The Süss MicroTek Mask Aligner MA6 is designed for high resolution photolithography. The 365nm exposure wavelength version is capable of 1.25 (1.0) um resolution in vacuum contact. All contact exposure programs (vacuum, low vacuum, hard, soft, proximity) are supplied. Two alignment options are available: top side alignment (TSA) with a split field or a video microscope and back side alignment (BSA) with BSA (video) microscope.

The aligner can also be used for bond alignment (for Wafer Bonder 02). Special training is required.

Product:	Süss mask aligner MA6
Year of purchase:	2014
Location:	Cleanroom E-4

User manual
The user manual and contact information can be found in LabManager - requires login

Tool training
Training on the tool requires users to complete the lithography TPT followed by the online tool training and a hands-on authorization training.
The tool training videos are part of the online tool training, but can also be viewed here (Operation) and here (Alignment).

Equipment performance and process related parameters

Purpose	Mask alignment and UV exposure Bond alignment
Exposure modes	Vacuum contact Hard contact Soft contact Proximity Flood exposure
Exposure light/filters	365 nm (i-line) broadband (i-, g-, h-lines), requires tool change 280-350 nm (UV300), requires tool change
Minimum resolution	~1.25 µm
Mask size	5x5 inches 7x7 inches Special holder for 4x2" designs on 5x5 inch
Alignment modes	Top side (TSA): ±1 µm (tool spec: ±2 µm) Back side (BSA): ±2 µm (tool spec: ±5 µm)
Substrate size	Small pieces: 1x1 cm 50 mm wafers 100 mm wafers 150 mm wafers
Allowed materials	All cleanroom allowed materials, except copper and steel III-V materials only allowed on dedicated chuck
Substrate batch	1

Process information

The Aligner: MA6-2 has an i-line notch filter installed. This results in an exposure light peak at 365nm. Compared to exposure on the KS Aligner, the optimal dose should be very similar. The 500W Hg-Xe lamp also enables exposure in the DUV range around 240nm. This functionality is not established yet, partly due to safety concerns.

Exposure dose

Information on UV exposure dose

Alignment mark design and locations

Alignment mark design and locations.

Light intensity and uniformity after lamp ignition

Light intensity and uniformity after lamp ignition. CP is constant power mode, CI is constant intensity mode. The accept limits for the CI mode is ±5%, the accept limit for the non-uniformity is 2%. CP mode has no accept limit.

The lamp requires about 15 minutes of on-time after lamp ignition, before the light output has stabilized, and users using the constant power mode should always wait for 15 minutes after ignition, before starting processing.

If users use the constant intensity mode, this waiting time is not necessary, since the internal light sensor automatically adjusts the output to match the setpoint value.

The non-uniformity of the light, in CI mode, is unaffected by the stabilization time.

Alignment

Top Side Alignment:

• TSA microscope standard objectives: 5x, and 10x (20x available)
• TSA microscope special objectives: 11.25x offset for smaller separation

• Minimum distance between TSA microscope objectives: 33 mm for standard objectives and 8 mm for the special objectives
  • Alignment of even smaller separations is possible using the "scan microscope" function
• Maximum distance between TSA microscope objectives: 160 mm
• TSA microscope travel range: X ±25 mm; Y +20/-75 mm (towards the flat)

Back Side Alignment:

• Minimum distance between BSA microscope objectives: 15 mm
• Maximum distance between BSA microscope objectives: 100 mm
• BSA microscope travel range: X +50/-16 mm; Y +50/-20 mm (towards the flat)
• BSA chuck view ranges:
  • 50 mm: X ±8-22 mm; Y ±0-6 mm
  • 100 mm: X ±14-46 mm; Y ±0-10 mm
  • 150 mm: X ±14-69 mm; Y ±0-10 mm

Microscope field of view (W x H, splitfield):

• TSA 5X:
  • Oculars: 1.3 mm x 2.6 mm (Ø2.6 mm full field)
  • Camera: 350 µm x 500 µm (700 µm x 500 µm full field)
• TSA 10X:
  • Oculars: 0.6 mm x 1.3 mm (Ø1.3 mm full field)
  • Camera: 150 µm x 250 µm (350 µm x 250 µm full field)
• TSA special:
  • Oculars: 0.55 mm x 1.1 mm (Ø1.1 mm full field)
  • Camera: 150 µm x 200 µm (300 µm x 200 µm full field)
• BSA camera:
  • Low: 1.5 mm x 2 mm (3 mm x 2 mm full field)
  • High: 450 µm x 650 µm (950 µm x 650 µm full field)

Quality Control (QC)

The purpose of the QC process is to check the intensity and uniformity of the exposure light in the Aligner: MA6-2, using a UV optometer. The optometer is placed at 5 fixed positions in the exposure area on a dedicated QC chuck, and the intensity of the light is measured.

The 5 intensity measurements are then used to calculate the average intensity as well as the peak uniformity error: $PUE[\mathrm{\%}]=\frac{max-min}{max+min}\cdot 100$.

Intensity accept limit:
The intensity should be corrected if the average intensity (from the 5 measurement points) deviates more than ±5% from nominal value. The nominal value for the Aligner: MA6-2 is 11 mW/cm², which means that the accept range is 10.45 - 11.55 mW/cm².

Uniformity accept limit:
The uniformity should be adjusted if the peak uniformity error is greater than 2%.

Documentation:

• The QC procedure for Aligner: MA6-2 - requires login
  
• The newest QC data for Aligner: MA6-2 - requires login

Aligner: Maskless 01

Aligner: Maskless 01 is located in E-4.

Tool description
The MLA1 is a UV exposure tool, which can be used for direct writing of digital mask designs, on photosensitive resists on chips, 50 mm and, 100 mm substrates. It is possible to load a 150 mm wafer, but the writable area is only 125 mm x 125 mm.

The MLA 100 Maskless Aligner is a direct exposure projection lithography tool. It has a 365 nm UV LED exposure light source, that exposes the patterns directly on photosensitive resists on chips, 50 mm, 100 mm, and 150 mm inch substrates. It uses digital mask files instead of physical shadow masks. The system offers top side alignment with high accuracy.

Product:	Heidelberg Instruments MLA100 Tabletop Maskless Aligner
Year of purchase:	2016
Location:	Cleanroom E-4

User manual
The user manual and contact information can be found in LabManager - requires login

Tool training
Training on the tool requires users to complete the lithography TPT followed by the online tool training and a hands-on authorization training.

Equipment performance and process related parameters

Purpose	Alignment and UV exposure
Exposure modes	Projection
Exposure light/filters	365 nm (LED), 8 nm FWHM
Dynamic focusing method	Pneumatic
Minimum resolution	~1 µm
Design file formats	GDS-II CIF DXF Gerber HIMT format
Alignment modes	Top side (TSA): ±2 µm (can be achieved: ±1 µm)
Substrate size	Maximum writing area: 125 mm x 125 mm Small pieces: 5 mm x 5 mm 50 mm wafers 100 mm wafers 150 mm wafers
Allowed materials	All cleanroom allowed materials Total height variation across the substrate must be less than ±40 µm - including wafer bow
Substrate batch	1

Process information

• Exposure technology
• Process parameters
• Substrate positioning
• Alignment
• Optimal use of the maskless aligner

Exposure dose

Information on UV exposure dose

Alignment mark design and locations

Alignment mark design and locations.

Quality Control (QC)

The purpose of the QC process is to check the optical performance and alignment accuracy of the maskless aligners. The optical performance is checked by making a dose/defocus test. The alignment accuracy is checked by making a global alignment test for topside alignment.

Dose/defoc limit:
Deviations in the optical performance are not easily corrected, and is likely due to contaminated or damaged writehead. If either the dose or defoc changes, the tool is investigated for writehead contamination and/or damage.

Alignment accuracy accept limit:
Must be within machine specifications, and should be adjusted if necessary. The alignment accuracy for MLA1 is ±1 µm.

Documentation:

• The QC procedure for Aligner: MLA1 - requires login
  
• The newest QC data for Aligner: MLA1 - requires login

Aligner: Maskless 02

Aligner: Maskless 02 is located in E-5.

Tool description
The MLA2 is a UV exposure tool, which can be used for direct writing of digital mask designs, on photosensitive resists on chips, 50 mm, 100 mm, 150 mm and 200 mm substrates.

Product:	Heidelberg Instruments MLA150 WM I Maskless Aligner
Year of purchase:	2018
Tool modification:	Modified from WM1 to WM2 in 2023
Location:	Cleanroom E-5

Features

• Optical Autofocus
• Pneumatic Autofocus
• Top side Alignment
• Back side Alignment
• Gray Scale Exposure
• Advanced Field Alignment Mode for alignment to individual chips/devices on the substrate
• High Aspect Ratio Mode for exposure of thick resists
• 200 x 200 mm exposure field

User manual
The user manual and contact information can be found in LabManager - requires login

Tool training
Training on the tool requires users to complete the lithography TPT followed by the online tool training and a hands-on authorization training.

Equipment performance and process related parameters

Purpose	Alignment and UV exposure
Exposure modes	Projection
Exposure light/filters	375 nm (laser diode array)
Dynamic focusing method	Optical Pneumatic
Minimum resolution	~1 µm
Design file formats	GDS-II CIF DXF Gerber HIMT format
Alignment modes	Top side (TSA): ±0.5 µm Back side (TSA): ±1 µm Advanced field alignment (chip-by-chip TSA): ±0.25 µm
Substrate size	Maximum writing area: 200 mm x 200 mm Small pieces: 3 mm x 3 mm with optical autofocus 50 mm wafers 100 mm wafers 150 mm wafers 200 mm wafers
Allowed materials	All cleanroom allowed materials Total height variation across the substrate must be less than ±90 µm - including wafer bow
Substrate batch	1

Process information

• Exposure technology
• Process Parameters
• Features
• Alignment

Exposure dose

Information on UV exposure dose

Alignment mark design and locations

Alignment mark design and locations.

Quality Control (QC)

The purpose of the QC process is to check the optical performance and alignment accuracy of the maskless aligners. The optical performance is checked by making a dose/defocus test. The alignment accuracy is checked by making a global alignment test for both topside alignment and back side alignment.

Dose/defoc limit:
Deviations in the optical performance are not easily corrected, and is likely due to contaminated or damaged writehead. If either the dose or defoc changes, the tool is investigated for writehead contamination and/or damage.

Alignment accuracy accept limit:
Must be within machine specifications, and should be adjusted if necessary. The top side alignment accuracy for MLA2 is ±0.5 µm. The backside alignment accuracy for MLA2 is ±1 µm.

Documentation:

• The QC procedure for Aligner: MLA2 - requires login
  
• The newest QC data for Aligner: MLA2 - requires login

Aligner: Maskless 03

Aligner: Maskless 03 is located in E-5.

Tool description
The MLA3 is a UV exposure tool, which can be used for direct writing of digital mask designs, on photosensitive resists on chips, 50 mm, 100 mm and 150 mm substrates. It is possible to load a 200 mm wafer, but the writable area is only 150 mm x 150 mm.

Product:	Heidelberg Instruments MLA150 WM II Maskless Aligner
Year of purchase:	2019
Location:	Cleanroom E-5

Features

• Pneumatic Autofocus
• Top side Alignment
• Back side Alignment
• Advanced Field Alignment Mode for alignment to individual chips/devices on the substrate

User manual
The user manual and contact information can be found in LabManager - requires login

Tool training
Training on the tool requires users to complete the lithography TPT followed by the online tool training and a hands-on authorization training.

Equipment performance and process related parameters

Purpose	Alignment and UV exposure
Exposure modes	Projection
Exposure light/filters	405 nm (laser diode array)
Dynamic focusing method	Pneumatic
Minimum resolution	~1 µm
Design file formats	GDS-II CIF DXF Gerber HIMT format
Alignment modes	Top side (TSA): ±0.5 µm Back side (TSA): ±1 µm Advanced field alignment (chip-by-chip TSA): ±0.25 µm
Substrate size	Maximum writing area: 150 mm x 150 mm Small pieces: 5 mm x 5 mm 50 mm wafers 100 mm wafers 150 mm wafers
Allowed materials	All cleanroom allowed materials Total height variation across the substrate must be less than ±90 µm - including wafer bow
Substrate batch	1

Process information

• Exposure technology
• Process Parameters
• Features
• Alignment

Exposure dose

Information on UV exposure dose

Alignment mark design and locations

Alignment mark design and locations.

Quality Control (QC)

The purpose of the QC process is to check the optical performance and alignment accuracy of the maskless aligners. The optical performance is checked by making a dose/defocus test. The alignment accuracy is checked by making a global alignment test for both topside alignment and back side alignment.

Dose/defoc limit:
Deviations in the optical performance are not easily corrected, and is likely due to contaminated or damaged writehead. If either the dose or defoc changes, the tool is investigated for writehead contamination and/or damage.

Alignment accuracy accept limit:
Must be within machine specifications, and should be adjusted if necessary. The top side alignment accuracy for MLA3 is ±0.5 µm. The backside alignment accuracy for MLA3 is ±1 µm.

Documentation:

• The QC procedure for Aligner: MLA3 - requires login
  
• The newest QC data for Aligner: MLA3 - requires login

Aligner: Maskless 04

Aligner: Maskless 04 is located in PolyFabLab in building 347.

Tool description
The logon password for the PC is "mla" (without quotation marks).

The Aligner: Maskless 04 (µMLA) is a UV exposure tool, which can be used for direct writing of digital mask designs, in photosensitive resists coated on chips, 50 mm, 100 mm, or 150 mm substrates. The aligner has two exposure modes; Raster mode by stepping a write field across the substrate using a DMD and the 365 nm LED source, and Vector mode by direct writing using a focused laser beam from the 405 nm diode laser source.

The µMLA Tabletop Maskless Aligner from Heidelberg, located in PolyFabLab in building 347, is a direct exposure lithography tool installed in 2024. It is a UV exposure system, that exposes the patterns directly on photosensitive resists on chips, 50 mm, 100 mm, or 150 mm substrates, without prior fabrication of a mask. The system offers top side alignment with good accuracy.

Product:	Heidelberg instruments µMLA Tabletop Maskless Aligner
Year of purchase:	2024
Location:	PolyFabLab

Features

• Optical Autofocus
• Pneumatic Autofocus
• Top side Alignment
• Gray Scale Exposure
• Direct laser writing (vector mode exposure)
• DMD projection writing (raster mode exposure)

User manual
The user manual and contact information can be found in LabManager - requires login

Equipment performance and process related parameters

Purpose	Alignment and UV exposure
Exposure modes	Projection (raster mode) Direct laser writing (vector mode)
Exposure light/filters	365 nm (LED) for projection 405 nm (laser diode array) for direct laser writing
Dynamic focusing method	Pneumatic
Minimum resolution	~1 µm
Design file formats	GDS-II CIF DXF Gerber HIMT format
Alignment modes	Top side (TSA): ±1 µm
Substrate size	Maximum writing area: 150 mm x 150 mm Small pieces: 3 mm x 3 mm with optical autofocus 50 mm wafers 100 mm wafers 150 mm wafers
Allowed materials	All PolyFabLab materials with sufficient stiffness and flatness Total height variation across the substrate must be less than ±80 µm - including wafer bow
Substrate batch	1

Process information

• Exposure technology
• Process parameters
• Substrate positioning
• Alignment

Alignment mark design and locations

Alignment mark design and locations.

Decommisioned tools

Inclined UV lamp was decommissioned 2023. Information about decommissioned tool can be found here.