Specific Process Knowledge/Lithography/Development/DUV developer

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Developer: TMAH UV-lithography

The Developer: TMAH Stepper is placed in F-3.

Tool description
This developer is dedicated for development of DUV resists. The developer is fully automatic and can run 1-25 substrates in a single batch. Supported substrate sizes are 100 mm, 150 mm and 200 mm (200 mm requires tool change). The machine is equipped with 1 developer line with 2,38% TMAH in water (AZ 726 MIF), 1 topside rinse line with DI water, 1 backside rinse line with DI water and 1 Nitrogen line for drying.

The developer dispense, puddle time, agitation, rinse and drying is controlled by the tool.

Product:	Süss MicroTec Gamma 2M developer
Year of purchase:	2013
Location:	Cleanroom F-3

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 video is part of the online tool training, but can also be viewed here.

Equipment performance and process related parameters

Tool purpose	Development of DUV resists: KrF M230Y KrF M35G May also be used for development of: AZ nLOF 2020 AZ MIR 701 AZ 5214E AZ 4562
Developer	AZ 726 MIF (2.38% TMAH)
Development method	Puddle
Handling method	Vacuum chuck for 100 mm & 150 mm wafers Vacuum chuck for 200 mm wafers (requires tool change)
Process temperature	Room temperature
Process agitation	1 cycles per 30 seconds
Process rinse	DI water
Substrate sizes	100 mm wafers 150 mm wafers 200 mm wafers (requires tool change)
Substrate materials	Silicon, III-V or glass substrates Film, or pattern, of all materials except Type IV
Substrate batch size	1-25
Media flow rates	AZ 726 MIF (TMAH): 500 ml/min Topside rinse DI water: 350 ml/min (with BSR+CR active) Backside rinse DI water: 45 ml/min (with TSR+CR active) Process Nitrogen: 50 l/min

Process information

The SEM picture of 250 nm pillars and lines. Exposure dose is 140 J/m2.

Processing on Developer TMAH stepper consists of the following steps:

• Post-exposure bake
• Puddle development
• Rinse

Features of Developer TMAH stepper:

• Cassette-to-cassette wafer handling
• In-line hotplates
• In-line cool plate
• Puddle developer module with rinse and dry

The development process will be performed by the customer together with the Photolith group of DTU Nanolab. In case you would like to do DUV lithography please contact Lithography team, who will consult you and run your wafers together with you.

Here you can find a chart‎ demonstrating a dependence between 250 nm line width/pillars diameter and exposure dose.

Post-exposure baking

Chemically amplified resists and cross-linking negative resists must be baked after exposure in order to finish the process initiated by the exposure light. Post-exposure bake, or PEB, is carried out on one of the two hotplates. After baking, the wafer is cooled for 20 seconds on the 20°C cool plate.

Puddle Development

Development on Developer TMAH stepper is divided into the following steps:

• Pre-wet
• Puddle dispense
• Development
• Spin-off

Pre-wet may be done using developer or DI water, or it may be skipped. It consists of a short dispense at medium spin speed (2s @ 1200 rpm).

Puddle dispense is done by dispensing developer (AZ 726 MIF) to the center of the wafer in order to build up a puddle of developer on the wafer. During the dispense, the wafer may be stopped or rotating slowly (30 rpm). The developer is dispensed at a rate of approximately 500 ml/min.

Development is carried out by leaving the developer puddle on the wafer for the duration of the development time (puddle time). The rotation is stopped during the development, but the developer may be agitated by rotating the wafer a few turns at low speed, e.g. 2s @ 30 rpm halfway through the development time, in order to facilitate good uniformity.

Spin-off is designed to stop the development by removing the developer from the wafer before the rinse. It is usually carried out as a short spin at high speed (3s @ 4000 rpm), but may be omitted.

Processes are divided into single puddle (SP), double puddle (DP), and multiple puddle (MP).

Rinse

After development, the substrate is rinsed using DI water, and dried using nitrogen.

The standard rinse and dry procedure is 30s at 4000 rpm with DIW being administered from the top at the center of the substrate, followed by a 10-15s dry at 3000 rpm using nitrogen from the top at the center of the substrate. The top side rinse is at a rate of approximately 350 ml/min. The flow rate of the nitrogen is 50 l/min, and the drying time is set according to the size of the substrate.

Standard Processes

NB: The list of standard processes is not necessarily complete, as new processes are added over time.

Development (only)

Development sequences on Developer TMAH stepper are divided into the following steps: Pre-wet, puddle dispense, development, spin-off, and finally rinse and dry.

Single puddle:

• 1004 DCH DEV 60s
• 1104 DCH 100mm SP 60s
• 1105 DCH 150mm SP 60s
• 1106 DCH 200mm SP 60s

Post-exposure baking (only)

Chemically amplified resists and cross-linking negative resists must be baked after exposure (Post-Exposure Bake, PEB) in order to finish the process initiated by the exposure light:

• (1000) DCH PEB 130C 60s
• (1001) DCH PEB 130C 90s

The baking is done at 130°C followed by a cooling step at 20°C for 20 seconds.

Combined PEB and development

For convenience, the PEB and development function of the machine may be combined in one sequence:

• (1002) DCH PEB_60s and DEV_60s
• (1003) DCH PEB_90s and DEV_60s