Specific Process Knowledge/Lithography/Development

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Development Comparison Table

	Manual beaker development	Developer: SU8 (Wet bench)	Developer: E-beam 02	Developer: TMAH Manual 02	Developer: TMAH UV-lithography	Developer: TMAH Stepper
Purpose	Fall-back option if you have a process, which is not compatible with the automatic, or semi-automatic, tools Requires individual risk assessment for TMAH development!	Development of: SU-8	Development of: ZEP 520A AR-P 6200.xx (CSAR)	Development of: AZ nLOF AZ MiR 701 AZ 5214E AZ 4562 DUV resists	Development of: AZ nLOF AZ MiR 701 AZ 5214E AZ 4562 DUV resists Post-exposure baking	Development of: DUV resists Post-exposure baking
Developer	Process dependent	mr-Dev 600 (PGMEA)	ZED N-50 AR 600-50	AZ 726 MIF (2.38% TMAH in water)	AZ 726 MIF (2.38% TMAH in water)	AZ 726 MIF (2.38% TMAH in water)
Method	Submersion	Submersion	Puddle	Puddle	Puddle	Puddle
Handling	Manual handling in beakers Chip bucket Single wafer carrier Carrier for up to 5 wafers	Chip bucket Single wafer carrier Carrier for up to 6 wafers	Vacuum-free edge-grip chucks for 50 mm, 100 mm & 150 mm, and 200 mm substrates Chip chuck for chips & 2" substrates	Vacuum-free edge-grip chucks for 50 mm, 100 mm & 150 mm, and 200 mm substrates Chip chuck for chips & 2" substrates	Vacuum chuck	Vacuum chuck
Process temperature	Room temperature	Room temperature	Room temperature	Room temperature	Room temperature	Room temperature
Process agitation	No agitation allowed	Magnetic stirrer	Rotation	Rotation	Rotation	Rotation
Process rinse	Process dependent	IPA	IPA	DI water	DI water	DI water
Substrate size	Chips 50 mm wafers 100 mm wafers 150 mm wafers	Chips 50 mm wafers 100 mm wafers 150 mm wafers 200 mm wafers	Chips (5mm to 2") 50 mm wafers 100 mm wafers 150 mm wafers 200 mm wafers	Chips (5mm to 2") 100 mm wafers 150 mm wafers	100 mm wafers 150 mm wafers 200 mm wafers (may require tool change)	100 mm wafers 150 mm wafers 200 mm wafers (may require tool change)
Allowed materials	All cleanroom approved materials	Silicon and glass substrates Film or pattern of all but Type IV	All cleanroom approved materials	All cleanroom approved materials Film or pattern of all types	Silicon and glass substrates Films, or patterned films, of any material except type IV (Pb, Te)	Silicon, III-V, and glass substrates Films, or patterned films, of any material except type IV (Pb, Te)
Batch size	1 - 5	1 - 6	1	1	1 - 25	1 - 25

Manual beaker development in fumehood

Beaker development, in fume hood 09: UV development or fume hood 10: e-beam development, is a fall-back option if you have a process, which is not compatible with the automatic, or semi-automatic, tools. We always recommend using, or at least trying, the automatic and semi-automatic tools, instead of using manual beaker development.

Manual beaker development is necessary for some processes, but should be avoided if possible, due to the fact that it is notoriously difficult to get a stable repeatable process - especially when multiple users are sharing the same process; everybody simply does things a bit different from each other, which leads to changes in the process outcome. Some processes have a very narrow process window, which makes them inherently sensitive to small changes in the development. The manual development also has a much greater chance of producing particles, both from the operator and the environment.

Finally the safety of the operator is at a significantly higher risk, since any manual handling of chemicals carries the risk of accidental spills with it. This is especially problematic if the developer is TMAH based, where direct skin exposure of >1% TMAH on a few percent of the body must be treated as a life-threatening event.

Special rules for manual beaker development of TMAH

• Automatic agitation methods are not allowed - this includes magnetic stirring or sonication
• Manual agitation methods, which create large waves or turbulence in the development solution, are not allowed
• Users must submit a risk assessment for any process requiring manual beaker development of TMAH based developers
• Users requiring manual beaker development of TMAH based developers must additionally provide valid reasons for not using the already available automatic and semi-automatic tools

Standard manual beaker development procedure

Standard procedure for manual beaker development in fume hood:
1) Submerge exposed substrate into development solution
2) When timer ends, move substrate directly into Rinse 1
3) After a few seconds, move substrate into Rinse 2*
4) Remove developed substrate for drying
(*It is allowed to omit the Rinse 2 step)

The standard procedure for manual beaker development in a fume hood is as follows:

1. Prepare development process
2. Perform development
3. Clean up

Prepare development process

• Write the chemical label, which must always be present in your chemical setup - your write your label before pouring the chemical
• Find the beakers required for your process
• Find the items required for holding/submerging your substrate during the process
• Find carriers or other storage units for placing your substrate after the process has finished
• Find a timer - make sure it works as you expect it to, before submerging your substrate into the development solution and discovering that the timer is in fact broken
• Get some cleanroom wipes and keep them nearby, for wiping any drops spilled during handling
• Do not cover too many of the exhaust holes in the fume hood table, as this will reduce the efficiency of the exhaust, which reduces safety
• Do not place your beakers too close to the fume hood sash, as this can make it difficult to efficiently extract the fumes escaping from the beakers, which reduces safety

Perform development

1. Put on the appropriate personal protection gear
2. Pour rinsing agent into Rinse 1 and Rinse 2 beakers - typically DI water or IPA
3. Pour development solution into development beaker
4. Place exposed substrate in the appropriate carrier
5. Set timer
6. Submerge substrate into development beaker
7. Start timer immediately
8. When timer is 5 seconds from ending, prepare to lift the substrate out of the development beaker
9. Lift substrate out of development beaker - it can help to lift it at a slight angle, to allow liquids to drain more easily from large surfaces
10. Submerge it immediately into Rinse 1
11. Agitate up/down for at least a few seconds
12. Move substrate into Rinse 2*
13. Agitate slightly
14. The developed substrate can now be removed and dried

(*It is allowed to omit the Rinse 2 step)

Clean up

• Pour Rinse 1 and Rinse 2 into appropriate waste: water goes into the sink, IPA goes into C-waste drain
• Rinse beakers with the DI-water gun
• Pour development solution into appropriate waste: solvent based developer goes into C-waste drain. NB! TMAH is an aqueous alkaline solution, which must never be mixed with solvents! TMAH waste goes into the dedicated TMAH waste container, stored in the chemical cabinet in E-4.
• If your developer solution is not TMAH based:
  • Rinse beaker 3 times, discard water into sink
• If your developer solution is TMAH based:
  • Rinse beaker once with DI-water and discard this into the TMAH waste
  • Rinse beaker two more times, discarding the water into the sink
• Hang all beakers to dry on the drying rack
• Erase the chemical label text
• Wipe any droplets on the fume hood surface
• Discard any napkins/other trash in the bin inside the fume hood

Developer: SU8 (Wet Bench)

The Developer: SU8 (Wet Bench) is located in E-4.

The SU8-Developer bench is a manually operated wet bench for submersion development of SU-8 photoresist in PGMEA (supplied in the cleanroom as mr-Dev 600). The development process is in two stages; one bath (FIRST) to dissolve the bulk of the resist, and a second, cleaner bath (FINAL) to finish the development. The development time is controlled manually by the user. After development, the substrates are rinsed with IPA in dedicated IPA bath and put for drying in the empty bath.

The user manual, user APV, and contact information can be found in LabManager: Developer: SU8(Wet Bench) - requires login

Process information

Several aspects of the outcome of SU-8 processing are affected by the development process. The lithographic resolution is affected by the time between PEB (post-exposure bake) and development, as the cross-linking process continues in the interface between exposed and unexposed regions even at room temperature. Cracks in the structures is affected by two things; the development time, and how much has previously been developed in the developer bath. Cracking is worse with longer development time, and worst in a new developer bath. The effect of the developer use quickly saturates (5-10 wafers). Finally, the stability of fine structures (high aspect ratio) is affected by the rinse after development, as the lower surface tension of IPA compared to PGMEA reduces pattern collapse during drying.

Development time is strongly dependent on the SU-8 thickness.

• Minimum development time: 1 min per 20 µm in FIRST

Suggestions:

• 2-5µm: 2 min. in FIRST; 2 min. in FINAL
• 40µm: 5 min. in FIRST; 5 min. in FINAL (however, 3 min. in FIRST and 2 min. in FINAL is sufficient)
• 180-250µm: 15 min. in FIRST; 15 min. in FINAL

Equipment performance and process related parameters

Purpose		Development of: SU-8
Developer		mr-Dev 600 (PGMEA)
Method	Development	Submersion
	Handling	Single wafer holder
Process parameters	Temperature	Room temperature
	Agitation	Magnetic stirrer
	Rinse	IPA
Substrates	Substrate size	100 mm wafers 150 mm wafers, check the liquid level in the baths 200 mm wafer, check the liquid level in the baths
	Allowed materials	Silicon and glass substrates Film, or pattern, of all materials except Type IV
	Batch	1-6

Developer: E-beam 02

Developer: E-beam 02 is located in E-4.

Developer: E-beam 02 is a manually operated, single substrate puddle developer. It uses the ZED-N50 or AR 600-50 developers and IPA for rinsing. The substrates are loaded manually one by one into the developer. Developer dispense, puddle time, IPA rinse, and drying is then performed automatically by the equipment.

Training video (for Developer: TMAH Manual, but it is the same model)

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

Process information

All recipes use the following structure:

1. Pressurize the developer canister
2. Dispense puddle while rotating substrate slowly
3. Puddle development while not rotating
4. Agitate substrate once per 15 seconds by rotating slowly for 1 second
5. Spin off developer
6. Clean substrate with IPA
7. Dry substrate and chamber with nitrogen

Multi-puddle recipes repeat steps 2-5 for the given number of puddles.

Process recipes
N50 recipes have the letter "N" in them. AR-600-50 recipes have the letter "A" in them. The number is the development time in seconds:

• 01 Rinse
• 02 N 15
• 03 N 30
• 04 N 60
• 05 N 90
• 06 N 120
• 07 N 180
• 08 N 300
• 09 N 600
• 10 N 2x60
• 11 N 5x60
• 12 A 15
• 13 A 30
• 14 A 60
• 15 A 90
• 16 A 120
• 17 A 180
• 18 A 300
• 19 A 600
• 20 A 2x60
• 21 A 5x60

Equipment performance and process related parameters

Purpose		Development of: CSAR ZEP520A
Developer		AR 600-50 ZED N-50
Method	Development	Puddle
	Handling	Chip chuck for chips Non-vacuum chuck for 2" wafers Non-vacuum chuck for 100 mm and 150 mm wafers Non-vacuum chuck for 200 mm wafers
Process parameters	Temperature	Room temperature
	Agitation	1 second rotational agitation at 30 rpm every 15 seconds
	Rinse	IPA
Substrates	Substrate size	Chips 2" wafers 100 mm wafers 150 mm wafers 200 mm wafers
	Allowed materials	All cleanroom approved materials Film, or pattern, of all materials except Type IV
	Batch size	1

Developer: TMAH Manual 02

Developer: TMAH Manual 02 is located in E-4.

Developer: TMAH Manual 02 is a manually operated, single substrate or chip puddle developer. It uses the TMAH based AZ 726 MIF developer (2.38 % TMAH in water with a small amount of wetting agent). The substrates or chips are loaded manually one by one into the developer. Developer dispense, puddle time, water rinse, and drying is performed automatically by the equipment.

Training video

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

Process information

All recipes use the following structure:

1. Pressurize the TMAH canister
2. Dispense puddle while rotating substrate slowly
3. Puddle development while not rotating
4. Agitate substrate once per 15 seconds by rotating slowly for 1 second
5. Spin off developer
6. Clean substrate and chamber with DI water
7. Dry substrate and chamber with nitrogen

Multi-puddle recipes repeat steps 2-5 for the given number of puddles.

Process recipes
SP: Single-puddle
MP: Multi-puddle

• 01 Rinse
• 02 SP 15
• 03 SP 30
• 04 SP 60
• 05 SP 90
• 06 SP 120
• 07 SP 300
• 08 MP 2x60
• 09 MP 5x60
• 91 SP test
• 92 MP test

Equipment performance and process related parameters

Purpose		Development of UV resists: AZ nLOF AZ MiR 701 AZ 5214E AZ 4562 Development of DUV resists: KRF M230Y KRF M35G
Developer		AZ 726 MIF (2.38% TMAH in water)
Method	Development	Puddle
	Handling	Chip chuck for chips and 2" wafers Non-vacuum chuck for 100 mm and 150 mm wafers
Process parameters	Temperature	Room temperature
	Agitation	1 second rotational agitation at 30 rpm every 15 seconds
	Rinse	DI water
Substrates	Substrate size	Chips (6-60 mm) 100 mm wafers 150 mm wafers
	Allowed materials	All cleanroom approved materials Film, or pattern, of all materials except Type IV
	Batch size	1

Developer TMAH UV-lithography

Developer: TMAH UV-lithography is located in E-4.

Developer TMAH UV-lithography was released Q4 2014.

Link to information about developer chuck size and hotplate pin positions.

Training video

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

Process Information

• General process information
• Process recommendations
• Standard processes

Equipment performance and process related parameters

Purpose		Development of AZ nLOF AZ MiR 701 AZ 5214E AZ 4562 DUV resists
Developer		AZ 726 MIF (2.38% TMAH in water)
Method	Development	Puddle
	Handling	Vacuum chuck
Process parameters	Temperature	Room temperature
	Agitation	Rotation
	Rinse	DI water
Substrates	Substrate size	100 mm wafers 150 mm wafers
	Allowed materials	Silicon and glass substrates Film or pattern of all except Type IV
	Batch	1-25

Developer: TMAH Stepper

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

This developer is dedicated for development of DUV resists. The developer is fully automatic and can run up to 25 substrates in a batch 4", 6", and 8" size (8" requires tool change). The machine is equipped with 1 developer line, in our case 2,38% TMAH in water (AZ 726 MIF), 1 topside rinse line with water, 1 backside rinse line with water and 1 N2 line for drying.

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

Process information

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

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.

Standard processes

Post-exposure bake sequences:

• (1000) DCH PEB 130C 60s 60s baking at 130°C; 20s cooling
• (1001) DCH PEB 130C 90s 90s baking at 130°C; 20s cooling

Development sequences:

• (1004) DCH DEV 60s 60s single puddle development

Combined PEB and development sequences:

• (1002) DCH PEB_60s and DEV_60s 60s baking at 130°C followed by 60s single puddle development
• (1003) DCH PEB_90s and DEV_60s 90s baking at 130°C followed by 60s single puddle development

The standard developer process consists of:

• pre-wetting with water (2.5s @ 1000rpm)
• developer dispense (2.5s @ 40rpm, corresponding to ~9ml)
• development (60s @ 0rpm)
• water rinse with BSR (5s @ 3000rpm)
• nitrogen drying (7s @ 4000rpm)

and has a cycle time of ~2 minutes

Equipment performance and process related parameters

Purpose		Development of DUV resist: KRF M230Y and KRF M35G
Developer		2,38% water based TMAH
Process parameters	Spin speed	10 - 5000 rpm
	Spin acceleration	100 - 10000 rpm/s
	Hotplate temperature	130°C for post exposure baking
Substrates	Substrate size	100 mm wafers 150 mm wafers 200 mm wafers (requires tool change)
	Allowed materials	Any standard cleanroom material
	Batch	1 - 25