Tystar10 MOS Polycrystalline Silicon

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Chapter 5.10

Tystar10
MOS Polycrystalline Silicon
LPCVD Furnace (4” and 6”)

(tystar10 - 386)
1.0 Titl e

Tystar10 MOS Polycrystalline Silicon LPCVD Furnace (4” and 6”) (tystar10)

2.0 Pu rpo s e

Tystar10 is a MOS 6” LPCVD poly-Si deposition tube, which is maintained for doped and undoped poly-
Si processes. This tube is capable of processing both 4” and 6” wafers. It can also be use to deposit
doped or undoped amorphous Si.

3.0 S cop e

This document has specific information about Tystar10 and the 4” & 6” doped and undoped LPCVD
poly-Si deposition tube. The tube is maintained for MOS processes with a total deposition thickness of
0.7 micron. Please refer to Chapter 5.0 of the lab manual for general information on LPCVD furnaces.

4.0 Appl i ca bl e D o cum ent s
Revision History
Chapter 5.0 of lab manual (LPCVD furnaces)

5.0 Def in it io ns & Pr oc e s s T e rm ino log y

5.1 MOS Tube: Tystar10 is a MOS tube dedicated to device fabrication.

5.2 Silane (SiH4): The main gas used for deposition of poly-Si.
5.3 Phosphine (PH3): A gas used to dope the polysilicon film. The Nanolab uses a 50% PH3 and

50% SiH4 mixture for safety.
5.4 ROP: Remote-Operation Panel

5.5 ALMACK : Alarm Acknowledge is a button used to proceed to next step in the deposition recipe.

5.6 ABORT: This key is used to abort the process. This is used for unloading wafers, where users
run the recipe again, after it has been completed and properly vented. The tube will open to
unload the user’s wafers followed by an abort to load the standby recipe.

Machine Interlock Messages

5.7 ANTLK: Above atmosphere interlock, no process gas can flow (including N2).
5.8 BNTLK: Below process pressure interlock. If tube pressure is above 2 Torr, no process gas can

flow.

5.9 DNTLK: Door interlock, door is not closed; no process gas can flow.

5.10 GNTLK: Gate valve interlock, gate valve is not open, no process gas can flow.

5.11 VNTLK: Vacuum interlock, pump problem, no process gas can flow.

tystar10 Chapter 5.10

6.0 Safety

Follow general safety guidelines in the lab as well as the specific safety rules as per follows:

6.1 Tytar10 utilizes potentially hazardous gases and high electric power (high amperages to heat its
elements). Do not open the front or the back panels, as it can expose you to high power circuitry.

6.2 Special care must be taken when the tube is aborted and while in deposition step. The toxic
process gases present will need to be properly vented. In an emergency situation (earthquake,
fire) the process can be aborted. Make sure toxic gases are properly vented by a series of pump
and purges and by running the “10purge” recipe. Ask process staff if you need help or if you have
any questions in this regard. Do not alter any of the standard processes and specially do no skip
any important purge or vent steps in your recipes.

6.3 All new recipes have to be checked by process staff, before they can be used on any of the Tylan
or Tystar furnaces.

6.4 This tube is a dedicated polysilicon tube, and process temperatures are typically around 615ºC.
Do not run the tube at temperatures above 650ºC, as it may crack the tube, which has a thick

coating of poly-Si deposited on its walls under stress.

7.0 Statistical/Process Data

Pertinent information can be found on the following sites:

7.1 Nanolab web page: Process Monitoring/Furnaces.

7.2 Problem and comments section under equipment section of Mercury.

7.3 Enable message for Tystar10.

8.0 Available Processes & Gases

The Tystar10 tube is assigned to MOS standard doped and undoped polysilicon processing.
8.1 Standard undoped poly-Si process: The standard undoped poly-Si “10suplya” recipe uses Silane

gas to deposit undoped film (PH3 = 0), at process pressure and temperature of 375 mTorr and
615ºC, respectively.
8.2 Standard doped poly-Si process: The standard doped polysilicon “10sdplya” recipe, uses Silane
(SiH4) and a fixed amount of Phosphine (PH3) to deposit doped poly-Si film at a process pressure
and temperature of 375 mTorr and 615ºC, respectively.
8.3 Variable doped poly-Si process: The variable doped poly-Si “10vdplya” recipe, allows for the user
to vary the amount of Silane (SiH4), Phosphine (PH3) and the process pressure below the
maximum specified amount in the recipe. Doped poly-Si film is deposited at a fixed process
temperature of 615ºC.
8.4 Doped and Undoped amorphous Si LPCVD – use the variable doped amorphous Si recipe,
10VDASIA.
8.5 The Tystar10 tube is calibrated in the temperature range of 500 – 650ºC. Do not attempt to run
any processes outside of this temperature range. Process temperatures above 650ºC are not
allowed. This will crack the tube.

8.6 Available gases on this tube are SiH4, PH3, N2 and N2 VAC (for pressure control).

9.0 Furnace Operation

9.1 Control Key Description

Many of the operational commands can be executed from the ROP. Function keys such as
“Recipe”, “Run”, “Hold”, “Clock”, “Status” and more are also available. The figure at the end of this

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tystar10 Chapter 5.10

chapter displays all these function keys. There are two ALMACK keys available on the ROP. The
one on the far right side just above the ABORT key is the only one that a lab member should use.

9.2 Operational Procedure/Guidelines

Recipes can be loaded from “TYSTAR10 recipe” diskette at the Tycom terminal. Run your
process and take your wafers out, after your process is completed. Note, you will need to wait for
the boat to completely go back in, before you can load the standby recipe. This means, once you
find your run completed, press ALMACK twice to advance out of the “flush & hold” step. Next, run
the recipe again and get your wafers out (this takes about 12 minutes). Then, press ALMACK to
advance through the unload step to send the boat in. Make sure the door is completely closed,
before you ABORT the process. Finally, load the standby recipe. Please note, aborting the tube
before the boat-loading step is completed, stops the boat loader in its tracks with the door open.

9.2.1 Recipes

Tystar10 recipes are on a dedicated diskette marked as “Tystar10 recipes”. These
recipes have a standard format with three pump and purge cycles before and after the
deposition step. This is designed to better control the film particles by keeping the tube
clean. There are standard doped & undoped polysilicon recipes available on Tystar10
disk, as well as standby, vent and purge recipes. The vent and purge recipes are
designed to speed up the recovery process.

See the Appendix for more details on the available recipes.

10suplya recipe: Standard undoped poly-Si process (PH3 = 0).
10sdplya recipe: Standard doped poly-Si process.
10vdplya recipe: Variable doped poly-Si recipe (var.SiH4, PH3, pressure)
10stnbya recipe: Standby recipe to be used, post poly-Si deposition.
10purge recipe: Additional recipe available to purge and vent the tube.*
10vent recipe: Additional recipe available to vent the tube.*

Note (*): The vent and purge recipes can be used for quick vent or pump/purge cycles. Pressing
the abort button, takes the recipe back to its first step. This may take a long time for the
tube to vent. This is because the initial step bleeds only about one liter of nitrogen into
the tube. It will take a long time to bring the tube to atmosphere. This can be
accomplished much faster by loading one of the two recipes noted above. However
take extreme care and make sure that you do not use the vent recipe when harmful
gases are present (aborted at deposition step). Load the purge recipe instead. This can
come in handy when an abort has occurred, while still in deposition step or if the origin
of the abort sequence is not known (did it abort at the deposition step?).

9.2.2 Recipe Modification and New Recipe Generation

As always, modification to standard recipes is not allowed. There is the 10vdplya recipe
available on the TYSTAR10 diskette for users to vary most process parameters. Talk to
process staff if you need to develop other recipes. Please put them on your own disk, not
the standard disk.

9.2.3 Recipe Loading
Type LO followed by recipe name and 10 to load the recipe onto the tube from the Tycom
terminal. e.g. “LO 10suplya 10”.

9.2.4 Running Recipe
Once the recipe is loaded, press the RUN button on the ROP terminal.

9.2.5 Wafer Loading

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tystar10 Chapter 5.10

9.2.6 Once the boat is out, replace dummy wafers with your work wafers. There is a 20 minute
window available for this task. After 20 minutes, the boat loader will automatically go into
9.2.7 the furnace. To keep the door open for another 20 minutes, press ALMACK to cycle back
9.2.8 to the “ boat unload” step and wait for the boat to come out.

Unloading Wafers

Once your process is completed, the furnace will wait in flush and hold step. You will
need to press ALMACK twice to vent the tube. You will then need to run the recipe again
to bring the boat loader out of the tube. Next, take your wafers out, then press ALMACK
to send the boat in. Make sure the door is completely closed. You can then abort the
process and load the standby recipe, before disabling the tool.

Standby Recipe (finishing up)

Once your run is completed and your process wafers are out, you will need to load & run
the standby recipe, 10stnbya. Doped poly-Si runs should be annealed.

Doped Poly-Si Films should be annealed to uniformly distribute the dopant in the
deposited film. This can be accomplished by annealing the wafers in the Tystar3 furnace.
You can use the recipe 3HIN2ANNL for 30 minutes at 950ºC for this purpose.

10.0 Troubleshooting Guidelines

10.1 Failed Leak Check

10.1.1 Check the tool status screen on the Tycom terminal (type in “DI ST 10”).

10.1.1.1 If “GNTLK“ or “VNTLK” is ON, stop and report it as a fault.
10.1.1.2
If “DNTLK” is ON, vent the tube, and run the process again. Try this a couple
of times, if necessary. Report it as fault, if it still fails. There may be door
sensor problems.

10.1.1.3 If no interlock is ON, vent the tube wipe the door and the o-ring. Run the
process again, and if it still fails, report it as a fault.

10.2 No Process Gas Flow

10.2.1 Check the tool status screen on the Tycom terminal (type in “DI ST 10”).

10.2.1.1 If any interlock is ON, report it as a fault.

10.2.1.2 Check the appropriate gas cylinder, if it is empty report as fault.

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11.0 Figures & Schematics

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12.0 Appendix

Recipes

Step 10suplya Time Step 10sdplya Time
----- -------- ----- --------
01 Description N/A 01 Description N/A
05 ------------------------------- 3 sec 05 ---------------------------- 3 sec
10 Initialize & system check 10 min 10 Initialize & system check 10 min
15 Unload alarm 20 min 15 Unload alarm 20 min
20 Unload Boat 3 sec 20 Unload Boat 3 sec
25 Load on almack 10 min 25 Load on almack 10 min
30 Load alarm 2 min 30 Load alarm 2 min
35 Load boat 5 min 35 Load boat 5 min
40 Check door closed 2 min 40 Check door closed 2 min
45 Pump1 2 min 45 Pump1 2 min
50 Purge1 2 min 50 Purge1 2 min
55 Pump2 2 min 55 Pump2 2 min
60 Purge2 1 min 60 Purge2 1 min
65 Pump3 20 min 65 Pump3 20 min
70 Leak check 1 min 70 Leak check 1 min
75 Set temp 5 min 75 Set temp 5 min
80 Set K constant 5 min 80 Set K constant 5 min
85 Temp stabilize 2 min 85 Temp stabilize 2 min
90 Temp check 1 min 90 Temp check 1 min
95 Pump4 1 min 95 Pump4 1 min
100 SiH4 flow (100 sccm) Variab 100 SiH4 & PH3 (100&4 sccm) Variabl
105 Pressure set (375 mTorr) le 105 Pressure set (375 mTorr) e
110 Deposition step (Time Var.) 2 min 110 Deposition step(Time Var.) 2 min
115 Pump1 2 min 115 Pump1 2 min
120 Purge1 2 min 120 Purge1 2 min
125 Pump2 2 min 125 Pump2 2 min
130 Purge2 2 min 130 Purge2 2 min
135 Pump3 2 min 135 Pump3 2 min
140 Purge3 1 hr 140 Purge3 1 hr
145 Flush and hold 5 sec 145 Flush and hold 5 sec
150 Branch to backfill 1 sec 150 Branch to backfill 1 sec
155 Loop back to flush & hold 5 min 155 Loop back to flush & hold 5 min
160 Backfill-1 7 min 160 Backfill-1 7 min
Backfill-2 Backfill-2
End End

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tystar10 Chapter 5.10

Step 10vdplya Time Step 10stnbya Time
----- -------- ----- --------
01 Description N/A 01 Description N/A
05 ---------------------------- 3 sec 05 ------------------- 10 min
10 Initialize & system check 10 min 10 Initialize 2 min
15 Unload alarm 20 min 15 Load 2 min
20 Unload Boat 3 sec 20 Check door closed 10 min
25 Load on almack 10 min 25 Short pump 2 min
30 Load alarm 2 min 30 Degas pump 1 min
35 Load boat 5 min 35 Hard pump 1 hr
40 Check door closed 2 min 40 Leak check 5 sec
45 Pump1 2 min 45 Standby 1 sec
50 Purge1 2 min 50 Branch to soft vent 5 min
55 Pump2 2 min 55 Loop back to standby 7 min
60 Purge2 1 min 60 Backfill-1
65 Pump3 20 min Backfill-2
70 Leak check 1 min End
75 Set temp 5 min
80 Set K constant 5 min
85 Temp stabilize 2 min
90 Temp check 1 min
95 Pump4 1 min
100 SiH4 & PH3 (variable gases allowed) Variable
105 Pressure set (max=flow+300 mTorr) 2 min
110 Deposition step(Time Var.) 2 min
115 Pump1 2 min
120 Purge1 2 min
125 Pump2 2 min
130 Purge2 2 min
135 Pump3 1 hr
140 Purge3 5 sec
145 Flush and hold 1 sec
150 Branch to backfill 5 min
155 Loop back to flush & hold 7 min
160 Backfill-1
Backfill-2
End

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