Specific Process Knowledge/Lithography/Resist/UVresist
UV resist comparison table
Comparison of specifications and feature space of the standard UV photoresists available at DTU Nanolab.
| Resist | AZ 5214E | AZ MiR 701 | AZ nLOF 2020 | AZ 4562 | SU-8 | TI Spray |
|---|---|---|---|---|---|---|
| Resist tone |
|
Positive | Negative | Positive | Negative |
|
| Thickness range | 1.5 - 4.2 µm | 1.5 - 4 µm | 1.5 - 4 µm | 5 - 10 µm | 1 - 200 µm | 0.5 - 5 µm |
| Coating tool |
Automatic spin coaters:
Manual spin coaters:
Spray coater |
Automatic spin coaters:
Manual spin coaters:
Spray coater |
Automatic spin coaters:
Manual spin coaters:
Spray coater |
Automatic spin coaters:
Manual spin coaters:
|
Manual spin coaters:
|
Spray coater |
| Spectral sensitivity | 310 - 420 nm | 310 - 445 nm | 310 - 380 nm | 310 - 445 nm | 300 - 375 nm | 310 - 440 nm |
| Exposure tool |
|
|
|
|
|
|
| Developer |
|
|
|
AZ 726 MIF (2.38% TMAH) |
mr-DEV 600 (PGMEA) |
AZ 726 MIF (2.38% TMAH) |
| Development rinse agent | DIW | DIW | DIW | DIW | IPA | DIW |
| Remover |
|
|
|
Remover 1165 (NMP) |
|
|
| Comments | Good adhesion for wet etch | High selectivity for dry etch | Negative sidewalls for lift-off | For processes with resist thickness between 6 µm and 25 µm |
|
TI spray resist is an image reversal resist, similar to AZ 5214E. The process flow will be similar to the process flows for 5214, except for the coating step. The exposure dose and development will depend on the specific process. |
Process flow examples
Comparison of specifications and feature space of the standard UV photoresists available at DTU Nanolab. These are just examples and may contain obsolete information regarding exposure dose, etc.
| Resist | AZ 5214E | AZ MIR 701 | AZ nLOF 2020 | AZ 4562 | SU-8 | Ti Spray |
|---|---|---|---|---|---|---|
| Maskless aligner |
NB! Most of the process knowledge about SU-8 is based in research groups |
|||||
| Mask aligner |
NB! Most of the process knowledge about SU-8 is based in research groups |
Other process flows: Chip on carrier: A procedure for UV lithography on a chip using automatic coater and developer.
Exposure dose
During exposure of the resist, the photoinitiator, or photo-active component, reacts with the exposure light, and starts the reaction which makes the resist develop in the developer.
In a positive resist, it makes the resist become soluble in the developer. In a negative resist, usually assisted by thermal energy in the post-exposure bake (PEB), it makes the resist insoluble in the developer. The amount of light required to fully develop the resist in the development process, is the exposure dose.
The optimal exposure dose is a function of many parameters, including the type of resist, the resist thickness, and the sensitivity of the resist.
Resist sensitivity
The resist sensitivity is a measure of how efficiently it reacts to the exposure light. Spectral sensitivity is the sensitivity of the resist as a function of wavelength. It is usually given simply as the range from the wavelength below which absorption in the resist material makes lithography impractical to the wavelength at which the photoinitiator is no longer efficiently activated.
Within the sensitivity range, the optical absorption is commonly used as a measure of sensitivity. A high absorption coefficient signifies a high sensitivity, as the light is absorbed by the photoinitiator. Because of spectral sensitivity, the optimal dose of a given resist type and thickness is also a function of the spectral distribution of the exposure light, i.e. the equipment used for the exposure. Using a combination of experience, calculation and assumptions, it may be possible to estimate the dose for an exposure equipment, if the exposure dose is already known on another equipment.
Due to reflection and refraction at the interface between the resist and the substrate, the optimal dose may also be a function of the type of substrate used. Unless otherwise stated, the exposure doses given below are for standard silicon wafers.
Apart from the already mentioned factors, the optimal dose also depends on the developer chemistry and the parameters used in the development process. Finally, the requirements to the lithographic process in terms of resolution, bias (line broadening), etch selectivity, side wall angle, etc. may narrow down, or widen, the process window. The exposure doses given in the sections below should be used as a starting point for individual fabrication process development.
Due to the process of bleaching, where the absorption of the resist changes during exposure, the exposure dose is unfortunately not always constant at different intensities of the exposure light. The exposure time is thus not always a linear function of the exposure intensity.
Calculate exposure time
In the maskless aligners, the dose is set directly as a process parameter in the job. In mask aligners, on the other hand, the parameter that is set is the exposure time, i.e. how long the shutter is open during the exposure.
The exposure dose, D [J/m2], in terms if exposure light intensity I [W/m2] and exposure time t [s], is given by:
Since the intensity is specific to the spectral sensitivity of the sensor used to measure the exposure light, and the exposure time is specific to the spectral distribution of the exposure light (cf. spectral sensitivity), this dose is specific to the combination of exposure source and optical sensor.
Given an exposure dose, the exposure time, t, is calculated as:
It is important to keep in mind that this exposure time is valid only for a specific combination of exposure source and optical sensor, as well as for a specific development process.
Exposure dose for mask aligners
The exposure doses listed below are for generic good exposure results, and can be a compromise between getting good lines, as well as good dots, in both clear field and dark field exposures. The optimal dose for any given specific project, could be different from the listed values.
All doses are for standard silicon wafers, unless otherwise stated. Development is done using 2.38% TMAH (AZ 726 MIF).
Aligner: MA6-1
The Aligner: MA6-1 has an i-line notch filter installed. This produces an exposure light peak around 365 nm with a FWHM of 7 nm.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control.
| Date | Operator | Film thickness | Exposure mode | Dose | Resolution | Comments | |
|---|---|---|---|---|---|---|---|
| AZ MIR 701 | Long ago | ? | 1.5 µm | ? | 180 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ MIR 701 | Long ago | ? | 2.0 µm | ? | 200 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ MIR 701 | Long ago | ? | 4.0 µm | ? | 400 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ 5214E | Long ago | ? | 1.5 µm | ? | 72 mJ/cm2 | ? µm | Not under regular quality control Development: 60 s puddle |
| AZ 5214E | Long ago | ? | 2.2 µm | ? | 80 mJ/cm2 | ? µm | Not under regular quality control Development: 60 s puddle |
| AZ 5214E | Long ago | ? | 4.2 µm | ? | 160 mJ/cm2 | ? µm | Not under regular quality control Development: 60 s puddle |
| AZ 5214E Image reversal |
Long ago | ? | 2.2 µm | ? | ? mJ/cm2 | ? µm | Not under regular quality control Reversal bake: 60 s @ 110°C Flood exposure: 500 mJ/cm2 Development: 60 s puddle |
| AZ nLOF 2020 | Long ago | ? | 2.0 µm | ? | 121 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle Side wall angle: ~15° For smaller angle (~5°): develop 30 seconds instead |
| AZ 4562 | Long ago | ? | 10 µm | ? | 510 mJ/cm2 | ≤5 µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Multiple exposures with 15 s pauses is recommended Degassing after exposure: none Development: 5 x 60 s multi puddle |
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the old resist versions.
Aligner: MA6-2
The Aligner: MA6-2 has an i-line notch filter installed. This produces an exposure light peak around 365 nm with a FWHM of 7 nm.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control.
| Date | Operator | Film thickness | Exposure mode | Dose | Resolution | Comments | |
|---|---|---|---|---|---|---|---|
| AZ MIR 701 | 2023-09-26 | taran | 1.5 µm | Hard contact | 150 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ 5214E | 2025-09-30 | jehem | 1.5 µm | Hard contact | 90 mJ/cm2 | 1.5 µm | Not under regular quality control Development: 60 s puddle |
| AZ 5214E Image reversal |
2023-01-11 | jehem | 2.2 µm | Hard contact | 22 mJ/cm2 | 2.0 µm | Not under regular quality control Reversal bake: 60 s @ 110°C Flood exposure: 500 mJ/cm2 Development: 60 s puddle |
| AZ nLOF 2020 | 2023-09-26 | taran | 2.0 µm | Hard contact | 121 mJ/cm2 | ? µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ 4562 | 2021-12-08 | jehem | 10 µm | Soft contact | 550 mJ/cm2 | ≤5 µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Single exposure Degassing after exposure: none Development: 5 x 60 s multi puddle |
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the new resist versions.
Exposure dose for maskless aligners
The exposure doses listed below are for generic good exposure results, and can be a compromise between getting good lines, as well as good dots, in both clear field and dark field exposures. The optimal dose and achievable resolution for any given specific project, could be different from the listed values.
All doses are for standard silicon wafers, unless otherwise stated. Development is done using 2.38% TMAH (AZ 726 MIF).
Aligner: Maskless 01
The Aligner: Maskless 01 has a 365 nm laser light source with a FWHM of ~1 nm. The test exposures on this tool were made using the pneumatic autofocus system.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control, except for the resist AZ 5214E.
| Date | Operator | Film thickness | Exposure mode | Dose | Defoc | Resolution | Comments | |
|---|---|---|---|---|---|---|---|---|
| AZ MIR 701 | 2025-10-16 | jehem | 1.5 µm | Fast | 325 mJ/cm2 | -1 | 1.5 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle Tested using dehydration reducing measures |
| AZ 5214E | 2025-08-15 | taran | 1.5 µm | Fast | 110 mJ/cm2 | -1 | 1.75 µm | See QC data for latest values Development: 60 s puddle |
| AZ 5214E Image reversal |
2023-04-05 | jehem | 2.2 µm | Fast | 20 mJ/cm2 possibly incorrect data |
-2 possibly incorrect data |
2.0 µm | Not under regular quality control Reversal bake: 60 s @ 110°C Flood exposure: 500 mJ/cm2 Development: 60 s puddle |
| AZ nLOF 2020 | 2023-07-06 | jehem | 2.0 µm | Fast | 180 mJ/cm2 | 0 | 1.5 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ 4562 | 2023-04-05 | jehem | 10 µm | Fast | 1050 mJ/cm2 possibly incorrect data |
-1 possibly incorrect data |
≤5 µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Single exposure Degassing after exposure: none Development: 5 x 60 s multi puddle |
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the new resist versions.
Dehydration reducing measures used for testing AZ MiR 701:
The CDA used for the pneumatic autofocus will dehydrate the resist. To reduce this effect, the writehead is parked far away from the write area while setting up the job for at least a few minutes, before starting the exposure.
Aligner: Maskless 02
The Aligner: Maskless 02 has a 375 nm laser light source with a FWHM of ~1 nm. The test exposures on this tool were made using the optical autofocus system, unless otherwise specified.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control, except for the resist AZ 5214E.
| Date | Operator | Film thickness | Exposure mode | Dose | Defoc | Resolution | Comments | |
|---|---|---|---|---|---|---|---|---|
| AZ MIR 701 | 2023-08-21 | taran | 1.5 µm | Quality | 325 mJ/cm2 | 1 | 1 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle Tested using dehydration reducing measures |
| AZ 5214E | 2024-12-09 | taran | 1.5 µm | Quality | 100 mJ/cm2 | 2 | 1.5 µm | See QC data for latest values Development: 60 s puddle |
| AZ 5214E Image reversal |
2023-04-17 | jehem | 2.2 µm | Quality | 35 mJ/cm2 | 0 | 1.5 µm | Not under regular quality control Reversal bake: 60 s @ 110°C Flood exposure: 500 mJ/cm2 Development: 60 s puddle |
| AZ nLOF 2020 | 2023-08-21 | taran | 2.0 µm | Quality | 450 mJ/cm2 | 0 | 1.5 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle |
| AZ 4562 | 2023-04-19 | jehem | 10 µm | Quality | 1150 mJ/cm2 | 0 | ≤5 µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Single exposure Degassing after exposure: none Development: 5 x 60 s multi puddle |
New writehead
As of 2023-03-21 the MLA2 has a new writehead installed, converting it from a write mode 1 tool to a write mode 2 tool. This makes all previous dose/defocus settings obsolete. This table contains only the dose/defocus values for the new writehead.
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the new resist versions.
Dehydration reducing measures used for testing AZ MiR 701:
The CDA used for the pneumatic autofocus will dehydrate the resist. To reduce this effect, the writehead is parked far away from the write area while setting up the job for at least a few minutes, before starting the exposure.
Aligner: Maskless 03
The Aligner: Maskless 03 has a 405 nm laser light source with a FWHM of ~1 nm. The test exposures on this tool were made using the pneumatic autofocus system.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control, except for the resist AZ 5214E.
| Date | Operator | Film thickness | Exposure mode | Dose | Defoc | Resolution | Comments | |
|---|---|---|---|---|---|---|---|---|
| AZ MIR 701 | 2025-10-20 | jehem | 1.5 µm | Quality | 175 mJ/cm2 | -1 | 1 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle Tested using dehydration reducing measures |
| AZ 5214E | 2025-09-02 | taran | 1.5 µm | Quality | 75 mJ/cm2 | 1 | 1 µm | See QC data for latest values Development: 60 s puddle |
| AZ 5214E Image reversal |
2023-06-30 | jehem | 2.2 µm | Quality | 50 mJ/cm2 | 0 | 1 µm | Not under regular quality control Reversal bake: 60 s @ 110°C Flood exposure: 500 mJ/cm2 Development: 60 s puddle |
| AZ nLOF 2020 | 2023-06-30 | jehem | 2 µm | Quality | 9000 mJ/cm2 | 2 | 1 µm | Not under regular quality control Post exposure bake: 60 s @ 110°C Development: 60 s puddle Due to the high dose required on this tool, it is recommended to process nLOF on tools with a more appropriate exposure light source |
| AZ 4562 | 2023-06-30 | jehem | 10 µm | Quality | 550 mJ/cm2 | 3 | ≤5 µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Single exposure Degassing after exposure: none Development: 5 x 60 s multi puddle |
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the new resist versions.
Dehydration reducing measures used for testing AZ MiR 701:
The CDA used for the pneumatic autofocus will dehydrate the resist. To reduce this effect, the writehead is parked far away from the write area while setting up the job for at least a few minutes, before starting the exposure.
Exposure dose when using AZ 351B developer (NaOH)
The exposure doses listed below are for generic good exposure results, and can be a compromise between getting good lines, as well as good dots, in both clear field and dark field exposures. The optimal dose for any given specific project, could be different from the listed values.
All doses are for standard silicon wafers, unless otherwise stated. Development is done using AZ 351B developer (NaOH) diluted 1:5.
Aligner: MA6-1
The Aligner: MA6-1 has an i-line notch filter installed. This produces an exposure light peak around 365 nm with a FWHM of 7 nm.
Quality control
Please note that the values listed in the table are not routinely tested as part of quality control.
| Date | Operator | Film thickness | Exposure mode | Dose | Resolution | Comments | |
|---|---|---|---|---|---|---|---|
| AZ 5214E | Long ago | ? | 1.5 µm | ? | 70 mJ/cm2 | ? µm | Not under regular quality control Development: 60 s submersion |
| AZ 5214E | Long ago | ? | 2.2 µm | ? | 72 mJ/cm2 | ? µm | Not under regular quality control Development: 70 s submersion |
| AZ 5214E | Long ago | ? | 4.2 µm | ? | 160 mJ/cm2 | ? µm | Not under regular quality control Development: 180 s submersion |
| AZ 5214E Image reversal |
Long ago | ? | 1.5 µm | ? | 30 mJ/cm2 | ? µm | Not under regular quality control Reversal bake: 100 s @ 110°C Flood exposure: 210 mJ/cm2 Development: 60 s submersion |
| AZ 5214E Image reversal |
Long ago | ? | 2.2 µm | ? | 35 mJ/cm2 | ? µm | Not under regular quality control Reversal bake: 100 s @ 110°C Flood exposure: 210 mJ/cm2 Development: 70 s submersion |
| AZ 4562 | Long ago | ? | 10 µm | ? | 320 mJ/cm2 | ? µm | Not under regular quality control Priming: HMDS Rehydration after SB: none Exposure: Multiple exposures with 15 s pauses is recommended Degassing after exposure: none Development: 300 s submersion |
New resists version in 2023
As of 2023-03-21 we no longer have any of the old versions of the resists: AZ 5214E, AZ 4562, AZ MiR 701. This table contains only information about the old resist versions.