fiji thermal and plasma atomic layer deposition system ... · pdf fileald system ucla...

ALD System UCLA Nanoelectronic Facility

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Fiji Thermal and Plasma Atomic Layer

Deposition System (ALD)

By Ultratech (Cambridge)

PREPARED BY: You-Sheng (Wilson) Lin, Nanolab Staff

7-30-2013

Superusers:

Steve Franz X68923

You-Sheng Lin X68923

Max Ho X49329


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1.0 SAFETY RULES

To avoid a fire or explosion, follow these instructions.

• Do not place flammable materials underneath, on or near the unit. Do not place

paperwork, wipes etc. on or near the unit.

• Do not run the system unattended; do not run the system overnight.

• Do not heat materials to temperatures above those recommended by the

manufacturer. Make sure heat monitoring and limiting devices are working

properly. Note the maximum temperature settings for different parts.

• ALD pulse valves are rated to 150oC and should not be heated above that

temperature. Center heater maximum temperature is 400oC, while outer heater

should not be set higher then 250oC because of the O-ring. The tee and flexible

bellows of pumping line should not be heated above 150oC.

• Temperature of the precursors should not exceed safety or decomposition

temperature of the chemical used. Maximum for the precursor heater jacket is

200oC.


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2.0 OVERVIEW

Principle of Al2O3 formation

Atomic Layer Deposition (ALD) is a technique that allows growth of thin films, atomic

layer by layer. Deposition of Al2O3 from water and trimethylaluminum (TMA) precursors

will be used to illustrate the principle of ALD. Recipes for other materials can be found

in the literature.

The chemical principle of Al2O3 growth from water and TMA is outlined in 5 steps

shown in Figure 1.

Step. 1: Put in a sample which is hydroxylated from exposure to air, oxygen or ozone

(Figure 1A).

Step 2: Pulse the TMA precursor; TMA will react with the OH groups on the surface.

TMA does not react with itself and the monolayer formed passivates the surface (Figure

1B, 1C).

Step 3: Remove unreacted TMA molecules by evacuation and/or purging with nitrogen

(Figure 1D).

Step 4: Pulse water (H2O) into the reactor. This will remove the CH3 groups, create Al-

O-Al bridges, and passivate surface with Al-OH. CH4 (methane) is formed as a gaseous

byproduct (Figure 1E, 1F).

Step 5: Remove unreacted H2O and CH4 molecules by evacuation and/or purging with

nitrogen (Figure 1G).

Steps (1)-(5) form a cycle. Each cycle produces a maximum of 1.1 Å of Al2O3 depending

on temperature.Thus, 100 cycles produces 11 nm of Al2O3.


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Similar reaction can be expected for HfO2 by using Tetrakis(dimethylamido)hafnium

(IV).

WARNING:

Trimethylaluminum (TMA) is a liquid at room temperature and is pyrophoric. This

means that it burns upon exposure to air.


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3.0 SYSTEM INFORMATION

The ALD system in the UCLA Nanoelectronic Facility is a ULTRATECH (Cambridge

NanoTech Fiji F200) equipped with a heated process chamber, remote plasma source,

turbomolecular pump, and automated load lock for transferring substrates. The system is

primarily intended for the deposition of a variety of thin films, including metals, oxides,

and nitrides. Typical film thicknesses are monolayers up to tens of nanometers. Thicker

films may be deposited but due to the low deposition rates (~ 3−20 nm/h) these films

would required deposition times of several hours.

Some key features are as follows.

• Highly conformable, well controlled layer by layer film deposition.

• Multi-layer film stacks possible.

• Aspect ratios of up to 450:1 in thermal mode or 20:1 in plasma mode are possible.

• Substrates up to 200 mm in diameter and 6 mm thick can be accommodated.

• Substrates may be heated up to 400°C, but most recipes only required up to 300°C.

• Process chamber turbomolecular pump provides a base pressure ~ 2 x 10-5 Torr.

• Load lock chamber with automated transfer of substrates into the process chamber.

• All depositions are performed from recipes.

There are two main modes of operation:

1. Continuously flowing nitrogen carrier gas while pulsing (adding) precursor and

pumping continuously

2. Pulsing precursors with stop valve closed and pumping in between pulses.


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3.1. System Overview:

3.2. System Control:

All controls for processing recipes, system startup/shutdown, configuration, and the

settings are performed via the supplied Windows platform laptop computer. The

computer is stored in a “computer drawer” in the electronics cabinet located below the

gas box:

Precursor bottles Chamber

Load Lock Computer Drawer EMO

Mechanical Pump

Chiller


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3.3. Software Overview:

3.4. Process Tab:

The Process Tab displays all the settings used to create/save/load and run recipes to

perform ALD. The user interface allows manual operations of basic functions such as

pumping down the system, turning on the heaters, setting gas flows and opening/closing

valves. These features are described next.


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Program Switch

Stops the Fiji software and turns off all outputs. Typically this button is not used except

to exit the system software prior to shutting down the system. For systems equipped with

a turbo, stopping the program will automatically decelerate the turbo before exiting.

Pump/Vent Toggle Switch (Radials display ‘next-state’ rather than ‘current state):

This button is disabled on systems with load/locks. Refer to the Vacuum System tab.

PUMP - pumps the system down to base pressure

VENT - vents the process chamber to atmospheric pressure

Closes the main stop valve to isolate the process chamber from the vacuum pump and

then opens the main chamber vent valve. A window prompts the user to click OK to

close the main chamber vent valve once atmospheric pressure is achieved.

Heaters Toggle Switch (Radials display ‘next-state’ rather than ‘current state):

ON - turns heaters ON (to default setpoints)

OFF - turns heaters OFF (all temperature setpoints are set to °C)

Run Toggle Switch (Radials display ‘next-state’ rather than ‘current state):

START - runs the recipe program

ABORT - aborts a current recipe run

When a process is running, “Program”, “Pump/Vent” and “Heaters” buttons are grey and

not clickable. To abort a run, simply click on Run ABORT button.


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4.0 OPERATING PROCEDURE

4.1. System Check:

1. Log into Labrunner to disable the interlock.

2. Check the logbook to make sure previous runs were OK.

3. Check the Water Chiller’s temperature at 70F.

4. Check the mechanical pump and make sure it is ok (“POWER OK” and

“RUNNING” green lights are on).

Mechanical Pump

“POWER OK” and

“RUNNING” green light

Step stool for access to load lock (Watch your step)


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5. Start filling out the logbook NOW (Date, Name, Badge Number, Film…. Etc).

6. Make sure all the precursor valves are completely closed, if not, please report

to Nanolab staff or superuser.

4.2 Wafer Loading:

1 From the Vacuum System tab, press “LL VENT” to vent the load lock chamber.

Water

Al Precursor Hf Precursor


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2 Wait 3 to 5 minutes until the load lock is completely vented. (Check the gap at load lock door).

3 Once the chamber is completely vented, Press OK on the software popup screen

to turn off the load lock vent valve.

4 Lift the load lock door up when atmospheric pressure is reached.

Under Vacuum

Vented to Atmosphere


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5 Load your wafer. Use the step stool to help reach the load lock door (Watch your

steps when on the step stool)

6 After loading your sample, close the door down.

To pump down LL and transfer wafer into the chamber:

7 From the Vacuum System screen, select Transfer Sample. Follow the system

prompts. (The system will automatically pump down the load lock. After the

pressure in the load lock and the process chamber is equilibrated, the main gate

valve separating the two chambers will automatically open; the substrate carrier

will then be loaded onto the heated chuck in the process chamber.)

8 At the end of transfer, follow the system prompts to visually verify the main

gate is clear, and then click Gate Clear to close the gate valve.

4.3 Load Recipe:

***You are NOT allowed to create or edit any recipe. Please contact Nanolab staff if

you have any special requirements***

Go to Process Window

1. Make sure that the system is pumped down.

2. Right click in the recipe steps table. This will bring up an options menu.


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3. Click on Load recipe in the drop down menu.

4. Load the recipe you would like to use. (Here are the current recipes)

a. Al2O3.thermal.200C

b. Al2O3.plasma.200C

c. HfO2.thermal.200C

d. HfO2.plasma.200C

5. Select the appropriate processing conditions required for your run. (Please see

appendix to choose the appropriate setting)

a. Select the number of cycles at GOTO step (Ex: 100 cycles, then you

will input 100).

b. Heater temperature (#12, #13, #14, #15) Typically at 200°C unless you

are changing your process temperature.


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c. Precursor Delivery line (#16 at 150°C) and precursor manifold (#17 at

150°C).

d. Precursor bottle temperature (TMA #18 @ room temperature – set at 0)

and (Hf 19 @ 65°C).

e. Purge time and wait time (Please see appendix).

f. Set APC at 9% .

6. Double check all the steps with the appendix.

7. Do not overwrite the standard recipe. If you want to save any recipe, please

create a new folder (make sure to discuss your process with nanolab staff).

8. Wait 10 minutes for the substrate/chamber to stabilize the temperature.

(Depending on process temperature and precursor)

9. Open the appropriate precursor valve.

10. Press Start to run the recipe.

11. Click Yes in the recipe start confirmation window.

12. Monitor the system to make sure your process is going well.

13. Record processing temperature and observe pulse time/process pressure.

14. Once complete, close precursor valve.


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4.4 Unload the wafer after deposition:

1. From the Vacuum System screen, select Transfer Sample. The substrate

carrier should be automatically transferred to the Load Lock.

2. Wait for your substrate to cool to near room temperature (Ex: for substrates

which were heated to 200°C, allow at least 20 minutes).

Go to Vacuum System screen, press LL Vent.

3. Wait 2-3 minutes for the LL to vent. During this interval, the load lock pressure

should rise to 760 Torr and a dialogue box will appear requesting

acknowledgement that the LL is at atmospheric pressure. DO NOT

acknowledge yet.

4. Gently try to lift the LL door. If it will not lift easily, wait another minute and

try again. Repeat until it lifts easily.

5. Once the LL door can be opened easily, press OK in the dialogue box to

acknowledge that the LL is at atmospheric pressure.

6. Fully open the LL door.

7. Approach the substrate carrier carefully in case it is hot. If it is, allow it to cool.

8. Remove your wafer from the substrate carrier.

9. Close the LL door.

10. From the Vacuum System screen, select PumpChamber & LL without

Turbo in order to pump down both the chamber and load lock.

4.5 Cleaning the ALD valve and manifold recipe (approximate 2 minutes)

1. Make sure all precursor valves are close.


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2. Go to Process Window and right click in the recipe steps table.

3. Select “Al_Headpurge” or “Hf_Headpurge” recipe depending on which

precursor you used.

4. Double check to make sure all precursor valves are close.

5. Make sure both Door Purge and Main Turbo Purge are on by clicking on them

(Should be light green).

6. Press Start to run recipe.

7. After your run is completed, make sure the following settings are as follows:

a. Heater temperature setting

i. All precursor bottle temperature = 0

ii. Heater Temperature (#12, #13, #14, #15) = 200°C

iii. Precursor Delivery line (#16 at 150°C)

iv. Precursor manifold (#17 at 150°C)

b. Argon idle flows:

i. MFC0 Ar Carrier = 5 sccm

ii. MFC1 Ar Plasma = 10 sccm

c. Turn off all 2 purges; make sure they are dark green (on the Vacuum

System screen).

i. Door Purge

ii. Main Turbo Purge


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4.6. Logbook and Interlock

1. Fill in all the information in the logbook.

a. User name and usage time

b. All temperatures and process times

c. Use ellipsometer to measure the film thickness and Index of reflection

2. Log out from the labrunner


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Appendix:

1. Standard Thermal Al2O3 Recipe

• Precursor: Trimethylaluminum, TMA, Al(CH3)3

• CAS #: 75-24-1

• Chemistry: Thermal ALD (Water, H2O)

• Process condition

o Trimethylaluminum (TMA): 0.06 second and unheated

o H2O: 0.06 second and unheated

Temperature

(C)

TMA Pulse

(s)

TMA Purge

(Wait)

(s)

H2O Pulse

(s)

H2O Purge

(Wait)

(s)

300 0.06 5 0.06 5 250 0.06 8 0.06 8 200 0.06 10 0.06 10

150 0.06 20 0.06 20 100 0.06 30 0.06 30 75 0.06 60 0.06 60 50 0.06 120 0.06 120 25 0.06 180 0.06 180

Door purge = 50sccm

0.06s room temperature TMA pulse ≈ 1.2mg


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Standard Thermal Al2O3 Recipe at 200°C

Instruction # Value

0 flow 0 20 Set precursor manifold stand-by Ar flow rate 1 flow 1 40 Set plasma source stand-by Ar flow rate 2 heater 12 200 Set trap/cone temperature 3 heater 13 200 Set reactor zone 1 temperature 4 heater 14 200 Set reactor zone 2 temperature 5 heater 15 200 Set chuck temperature 6 heater 16 150 Set precursor delivery line to 150°C 7 heater 17 150 Set precursor manifold to 150°C 8 stabilize 12 Wait for trap/cone temperature to stabilize 9 stabilize 13 Wait for reactor zone 1 temperature to stabilize 10 stabilize 14 Wait for reactor zone 2 temperature to stabilize 11 stabilize 15 Wait for chuck temperature to stabilize 12 wait 600 Wait for substrate temperature to stabilize 13 flow 0 30 Set precursor manifold Ar for expo step 14 flow 1 100 Set plasma source Ar for expo step 15 APC 9 Set throttle valve.

16 wait 10 Wait for Ar MFCs to stabilize

17 pulse 1 0.06 Begin loop. Pulse TMA. TMA = TMA ALD valve number

18 wait 10 Purge TMA and reaction by-products

19 pulse 0 0.06 Pulse H2O. H2O = H2O ALD valve number 20 wait 10 Purge H2O and reaction by-products

21 goto 17 X Input # of cycles, number, x = cycles, GPC ~ 1A/cycle

22 flow 0 5 Set precursor manifold stand-by Ar flow rate 23 flow 1 10 Set plasma source stand-by Ar flow rate 24 APC 100 Open throttle valve. If no throttle valve, remove this line

25 Turbopurge 0 26 Doorpurge 0


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2. Standard Plasma Al2O3 Recipe

• Precursor: Trimethylaluminum, TMA, Al(CH3)3

• CAS #: 75-24-1

• Chemistry: Plasma ALD (Oxygen, O2)

• Process condition

o Trimethylaluminum (TMA): 0.06 second and unheated

o O2: 20 seconds

Temperature

(C)

TMA Pulse

(s)

TMA Purge

(Wait)

(s)

O2 Pulse

(s)

O2 Purge

(Wait)

(s)

300 0.06 5 20 5 250 0.06 8 20 5 200 0.06 10 20 5

150 0.06 20 20 5 100 0.06 30 20 5 75 0.06 60 20 5 50 0.06 120 20 5 25 0.06 180 20 5

Door purge = 50sccm

0.06s room temperature TMA pulse ≈ 1.2mg


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Standard Plasma Al2O3 Recipe at 200°C

Instruction # Value 0 flow 0 20 Set precursor manifold stand-by Ar flow rate 1 flow 1 40 Set plasma source stand-by Ar flow rate 2 heater 12 200 Set trap/cone temperature 3 heater 13 200 Set reactor zone 1 temperature 4 heater 14 200 Set reactor zone 2 temperature 5 heater 15 200 Set chuck temperature 6 heater 16 150 Set precursor delivery line to 150°C 7 heater 17 150 Set precursor manifold to 150°C 8 stabilize 12 Wait for trap/cone temperature to stabilize 9 stabilize 13 Wait for reactor zone 1 temperature to stabilize 10 stabilize 14 Wait for reactor zone 2 temperature to stabilize 11 stabilize 15 Wait for chuck temperature to stabilize 12 wait 600 Wait for substrate temperature to stabilize 13 flow 0 30 14 flow 1 100 15 APC 9 Set throttle valve 16 wait 10 Wait for Ar MFCs to stabilize 17 MFCvalve 3 1 Set precursor manifold Ar for expo step 18 wait 20 19 pulse 1 0.06 Begin loop. Pulse TMA. TMA = TMA ALD

Valve number 20 wait 10 Purge TMA and reaction by-products 21 flow 3 50 Start O2 flow 20 plasma 300 Turn on plasma. 23 wait 20 24 plasma 0 0 Turn off plasma. 25 flow 3 0 Start O2 flow. 26 wait 5 Purge O2 and reaction by-products 27 goto 19 X Input # of cycles, number, x = cycles, GPC ~

1A/cycle

28 flow 0 5 29 flow 1 10 30 flow 3 0 Turn off O2 31 APC 100 Open throttle valve. If no throttle valve, remove

this line 32 turbopurge 0 33 doorpurge 0


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3. Standard Thermal HfO2 Recipe

• Precursors: Tetrakis(Dimethylamido)Hafnium (Hf(NMe2)4)

• CAS#: 19962-11-9

• Chemistry: Thermal ALD (Hf(NMe2)4) , H2O

• Process condition:

o Tetrakis(Dimethylamido)Hafnium (Hf(NMe2)4): 0.25 second and

heated to 75°C

o H2O: 0.06 second and unheated

Temperature

(C)

Hf(NMe2)4

Pulse

(s)

Hf(NMe2)4

Purge

(Wait)

(s)

H2O Pulse

(s)

H2O Purge

(Wait)

(s)

200 0.25 15 0.06 15

90 0.25 120 0.06 120


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Standard Thermal HfO2 Recipe at 200°C

Instruction # Value

0 flow 0 20 Set precursor manifold stand-by Ar flow rate 1 flow 1 40 Set plasma source stand-by Ar flow rate 2 heater 12 200 Set trap/cone temperature 3 heater 13 200 Set reactor zone 1 temperature 4 heater 14 200 Set reactor zone 2 temperature 5 heater 15 200 Set chuck temperature 6 heater 16 150 Set precursor delivery line to 150°C 7 heater 17 150 Set precursor manifold to 150°C 8 heater 19 75 Set precursor bottle to 75°C 9 stabilize 12 Wait for trap/cone temperature to stabilize 10 stabilize 13 Wait for reactor zone 1 temperature to stabilize 11 stabilize 14 Wait for reactor zone 2 temperature to stabilize 12 stabilize 15 Wait for chuck temperature to stabilize 13 Stabilize 19 Wait for precursor bottle to stabilize 14 wait 600 Wait for substrate temperature to stabilize 15 flow 0 60 Set precursor manifold Ar for expo step 16 flow 1 200 Set plasma source Ar for expo step 17 APC 9 Set throttle valve.

18 wait 20 Wait for Ar MFCs to stabilize

19 pulse 0 0.06 Begin loop. Pulse H2O. H2O = H2O ALD valve number 20 wait 10 Purge TMA and reaction by-products

21 pulse 2 0.25 Pulse Hf. Hf=Hf ALD valve number 22 wait 10 Purge H2O and reaction by-products

23 goto 19 X Input # of cycles, number, x = cycles, GPC ~ 1A/cycle

24 flow 0 5 Set precursor manifold stand-by Ar flow rate 25 flow 1 10 Set plasma source stand-by Ar flow rate 26 APC 100 Open throttle valve. If no throttle valve, remove this line

27 Turbopurge 0 28 Doorpurge 0


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4. Standard Plasma HfO2 Recipe

• Precursors: Tetrakis(Dimethylamido)Hafnium (Hf(NMe2)4)

• CAS#: 19962-11-9

• Chemistry: Thermal ALD (Hf(NMe2)4) , O2

• Process condition:

o Tetrakis(Dimethylamido)Hafnium (Hf(NMe2)4): 0.25 second

and heated to 75°C

o O2: 20 second and unheated

Temperature

(C)

Hf(NMe2)4

Pulse

(s)

Hf(NMe2)4

Purge

(Wait)

(s)

O2 Puluse

(s)

O2 Purge

(Wait)

(s)

250 0.25 5 20 5 200 0.25 5 20 5

150 0.25 30 20 5 90 0.25 120 120 20


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Standard Plasma HfO2 Recipe at 200°C

Instruction # Value 0 flow 0 20 Set precursor manifold stand-by Ar flow rate 1 flow 1 40 Set plasma source stand-by Ar flow rate 2 heater 12 200 Set trap/cone temperature 3 heater 13 200 Set reactor zone 1 temperature 4 heater 14 200 Set reactor zone 2 temperature 5 heater 15 200 Set chuck temperature 6 heater 16 150 Set precursor delivery line to 150°C 7 heater 17 150 Set precursor manifold to 150°C 8 Heater 19 75 Set precursor bottle to 75°C 9 stabilize 12 Wait for trap/cone temperature to stabilize 10 stabilize 13 Wait for reactor zone 1 temperature to stabilize 11 stabilize 14 Wait for reactor zone 2 temperature to stabilize 12 stabilize 15 Wait for chuck temperature to stabilize 13 stabilize 19 Wait for precursor bottle to stabilize 14 wait 600 Wait for substrate temperature to stabilize 15 MFCvalve 3 1 Set precursor manifold Ar for expo step 16 flow 0 60 17 flow 1 200 18 APC 9 Set throttle valve 19 wait 20 Wait for Ar MFCs to stabilize 20 pulse 2 0.25 Begin loop. Pulse Hf. Hf = Hf ALD Valve number 21 wait 5 Purge Hf and reaction by-products 22 flow 3 20 Start O2 flow 23 wait 5 24 plasma 300 Turn on plasma. 25 wait 20 26 plasma 0 0 Turn off plasma. 27 flow 3 0 Start O2 flow. 28 wait 5 Purge O2 and reaction by-products 29 goto 19 X Input # of cycles, number, x = cycles, GPC ~

1A/cycle

30 flow 0 5 31 flow 1 10 32 flow 3 0 Turn off O2 33 APC 100 Open throttle valve. If no throttle valve, remove

this line 34 turbopurge 0 35 doorpurge 0

fiji thermal and plasma atomic layer deposition system ... · pdf fileald system ucla...

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