Chapter
5.18
Tystar
18
MOS
Clean Aluminum Sintering Atmospheric Furnace
(4”
and 6”)
(tystar18)
1.0
Title
Tystar18 MOS Clean Aluminum Sintering Atmospheric Furnace
2.0
Purpose
Tystar18 is a MOS clean atmospheric furnace for
Sintering/Alloying. It can also be used for annealing in nitrogen ambient at
temperatures not exceeding 600°C.
3.0
Scope
This document provides operational
procedures for Tystar18 furnace, recipe loading from FCS10 furnace computer,
and guideline for user level troubleshooting.
4.0
Applicable Documents
4.1
Chapter
5.0 of the lab manual (Tystar/Tylan Furnaces).
4.2
TYTAN Furnace System Manual, includes FCS10, TCU, MFS460 (Copy in
Office)
4.3
The MSDS in the Office/lobby, which explains the safety concerns
for the specific gases used in Tystar18 (includes MSDS).
5.0
Definitions & Process Terminology
5.1
MOS Furnace: This kind of furnaces is used for processing MOS devices (IC),
whose performance can be greatly impacted by trace contaminants. Wafers
processed in MOS clean furnaces should absolutely be MOS compatible (IC
device). Absolutely no metal film in any MOS Furnace, except the MOS sintering
furnace (Tystar 18), which allows only Al film.
5.2
Non-MOS Furnace: This kind of furnaces is used for processing
Non-MOS clean devices (Non IC) such as; MEMS or similar application. Any wafer that
has been processed in a non-MOS furnace is not allowed in any MOS clean
furnace.
5.3
Atmospheric furnace: This type of furnace does not a vacuum
pump. The process gas is fed into the quartz tube from the back end (source
end), and flows toward the front end (load) of the furnace.
6.0
Safety
Follow general safety guidelines in the lab and the specific
safety rules as per follows:
6.1
Tystar18 utilizes high electric power (high amperages)
heating elements. Do not touch high
power electrical part inside panels of the furnace.
6.2
Special care must be taken when the process aborts. In the event
process goes into SPECIAL HOLD, immediately inform process staff to look into
the problem. There may be hazardous gases still present in the tube. Process
staff will decide whether to continue the process and/or take proper action/s
to remedy the situation.
DO NOT ATTEMPT TO
OPEN THE TUBE, WHEN IT IS IN SPECIAL HOLD.
6.3
All new recipes have to be approved by the process staff, before
they can be used on any Tylan or Tystar furnaces.
6.4
Burn Hazard. Furnace cantilevers, boats, and wafers come out of the furnace
are very hot. Wear face shield when
loading/unloading wafers. Proceed with caution.
7.0
Statistical/Process Data
7.1
Problem and Comment under Equipment section of the wand.
7.2
Enable message for Tystar18.
8.0
Available Process, Gases, Process Notes
8.1
Only MOS wafers can be processed in this furnace, and after
getting proper clean steps. Refer to the Furnace Pre-Cleaning
Requirement Table in Chapter 1.7
(Material and Process Compatibility Policy) for specific instruction for metal,
and non-metal wafer cleaning. Note: Resist coated metal wafers will need to get
proper resist strip (ash & wet strip) plus a proper rinse step, before
going into Tystar18 furnace. None metal resist coated wafers will require wet
strip plus the standard pre-furnace clean steps (sink8+sink6). New wafers only
require the sink6 clean.
8.2
Wafers coming out of another MOS Tystar/Tylan furnace, and going
straight into the Tystar18 with no delay, will not require a clean step in
between.
8.3
Metal wafers: Only wafers with Al/2%Si film or other type of metal
films that do not melt below 1500ºC (refractory metal) can be processed in this
furnace.
Available Processes
8.4
H2SINT4A.018: Regular forming gas (10% H2, 90% N2)
sintering at 400°C.
8.5
H2SINT6A.018: Regular forming gas (10% H2, 90% N2)
sintering at 600°C.
8.6
D2SINT4A.018: Special forming gas (10% D2, 90% N2)
sintering at 400°C.
8.7
D2SINT6A.018: Special forming gas (10% D2, 90% N2)
sintering at 600°C.
8.8
LTANNLA.018: Variable low temperature (<= 600°C) annealing
using either H2N2 or D2N2..
8.9
Please contact process staff for any customized process(es) you
may need.
Available Gases
8.10
H2/N2 (10%H2,90% N2): Forming gas is
used because many metal films are sensitive to oxygen at elevated temperatures.
The hydrogen is responsible for passivating and deactivating the interface
traps.
8.11
D2/N2 (10%D2,90% N2): Special kind of
forming gas for advanced sintering. Deuterium (D2) is not radioactive. Use the same guidelines as for the regular
forming gas (H2/N2). D2/N2 is relatively expensive. Please do not abuse.
8.12
Nitrogen (N2): Used to keep the process tube in a
clean and inert environment.
8.13
Oxygen (O2): not connected.
8.14
Argon (Ar): not connected.
8.15
The maximum temperature for Tystar18 is 600°C. Any attempt to
go above this temperature will result in damaging the heating system of the
furnace.
8.16
Load and unloads wafers only as quickly/safely possible. Avoid opening
the tube for more than 5 minutes, which may cause the tube temperature to drop
significantly. In such case, the process temperature may not reach the set
point, as the sintering process time is relatively short (20 minutes, or so).
8.17
The sintering recipes are optimized when the starting temperature
is at the set point for all the five heater zones. Please leave at least 30
minutes between two consecutive runs for temperature to recover.
8.18
If your process temperature is different from the previous run, you
should load your recipe and wait until the temperature stabilizes before
running the process.
8.19
After the sintering/annealing process is completed, furnace door
automatically opens, so it is very important that you time your process
properly, be back in time to take your wafers out. DO NOT LET THE FURNACE
DOOR BE LEFT OPEN FOR A LONG PERIOD OF TIME. Tystar18 furnace
stabilizes fairly quickly provided you avoid lengthy wafer loading time. You
should be able to add about 10 minutes (Temperature stabilization time) to your
sintering time to arrive at your overall process time, noted above.
8.20
All Tystar18 recipes use 4-letter step ID’s, instead of 4-digit
numbers used in the past. The commonly used ID’s are noted below:
IDLE IDLE state STRT process StaRT
LOAD LOAD/unload wafers BTIN BoaT moves INto the tube
CKDR ChecK DooR interlock STEQ Sintering Temp EQuilibrium
SINT SINTering step GOFF process gas turn OFF.
BTOU BoaR OUt automatically UNLD UNLoaD wafer
CLDR Close DooR PEND Process END
ABRT ABoRT sequence SHLD Special HoLD
9.0
Overall Furnace Operation
9.1
General Information and Menu Keypad Explanation
Tystar18 is a five-zone atmospheric pressure furnace. It operates
as a stand-alone unit that comprises of three modules: wafers load/unload
module, furnace/process tube module, and gas control module. It has it’s own computer, FCS10, whose
display panel and keypad are located on the left side of the wafer load/unload
module. The furnace operation is
controlled through special function keys, and a series of menu commands.
Furnace temperature is controlled by the TCU computer board, which utilizes a
proprietary PID algorithm. The temperatures of all 5 furnace zones; i.e. Load,
Load/Center, Center, Source/Center, and Source can be independently set. The
process gases are controlled by the MFS460 controller and five hardware
interlocks in it to insure safe operation of the tool.
9.1.1
Front Panel Special Function Buttons and Keypad Description (see Section 11.1 for the schematics
of the front panel)
ABORT ***USE ONLY IN EMERGENGY***, e.g. fire, toxic gas leak. DO NOT use this
key to abort a recipe in progress. If you must stop a recipe, please contact a super-user
or process staff. They know the proper procedure for stopping
process/evacuating toxic gases from the furnace. This action requires password,
as well.
MENU Display the main menu (See
the Appendix for the description of all menu commands)
NEXT PAGE Used to display more
information/instructions on the display. Use when prompted, otherwise the
computer will freeze and you will need to find a process staff to reboot it.
CMD Used for certain special
functions. (Mostly used with GS commands, Section 9.1.2)
Arrow Keys Used when prompted to select a
recipe. Do not use it as a DEL/BACKSPACE key when entering alphanumerical
inputs. Otherwise, the computer will freeze and you will need to find a process
staff to reboot it.
Alpha-
Numeric Keys Used to enter process parameters, e.g.
gas flows, pressure, deposition time, and etc.
ENTER Used to enter the menu
command or alphanumerical inputs.
CLEAR Used to clear the error on the
alphanumerical key input.
RUN Run the recipe loaded in
the computer memory.
HOLD Hold a recipe step at its
present process condition. Press RUN key to resume the process.
EVENT Acknowledge the
process to go to the next step of the recipe when the current step time has not
finished yet. e.g., after you finish loading the wafers and want to close the
furnace door. Note that some process recipe steps cannot be EVENTed.
BOAT IN/OUT Move
the boats in/out of the process tube manually, independent of the recipe. These
are toggle switches, i.e. push once to turn on and the second time to turn off.
If both are ON at the same time, then the boats stop moving.
ALARM ACK Silences an alarm, but does not
correct the alarm condition. Alarm conditions are displayed on the bottom line
of the screen. In most cases, the computer will clear the alarm conditions by
itself. If not, report the problem on the WAND.
9.1.2
Commonly Used MENU Commands (press MENU button, then enter the two
letter commands):
DS Displays the status of the
furnace. An example is shown in Section
11.2.
DH Displays the process history from
the last time the RUN button was pressed to present time.
DR Displays the contents of the
selected recipe.
GS Changes the Display to graphic mode.
It shows large characters with only selected process information. Use CMD
button to select process parameters to be displayed.
RL Loads process recipes. You will be
prompted to use the Arrow Keys to select a recipe. Afterward, press ENTER
button twice. The computer will prompt you to enter process parameters, if/when
needed.
9.1.3
Process Gas Flow Interlocks
DNTLK Door interlock. When ON, it indicates that
the tube door is not closed properly and none of the process gas, except
nitrogen, will flow.
9.2
Processing a Run
Load Recipe
9.2.1
Enable TYSTAR18 on the WAND
9.2.2
Press MENU button, then enter DS. The screen displays the status
of the furnace. Make sure the process is in the IDLE state.
9.2.3
Press MENU button, and then enter RL for screen to show a list of
the available recipes. Use the arrow keys to highlight the recipe that you plan
to load, then press ENTER twice.
9.2.4
The computer will prompt you to enter some process parameters
defined in the recipe. Input values of previous run will be displayed for your
reference. Enter your values in the same format shown on the screen, even if it
is exactly the same as what is displayed on the screen. Press ENTER after
typing each process variable value.
9.2.5
Use the CLEAR key if you need to erase a wrong value,
entered. DO NOT USE THE ARROW KEY TO
MOVE THE CURSOR! This will cause the software to crash and all the recipes
might be lost. You will have to find a super user or staff to reboot the
furnace computer.
9.2.6
Time is entered in the format of HH.MM.SS. Do not enter 00.00.00
since it hold the process at the step indefinitely. If you want to skip the
step, enter 00.00.01 which is the shortest time for a step. Usually, the
process parameters cannot respond within one second, and the process skips to
the next step.
9.2.7
Once you have finished entering all of your required values, press
MENUE, then DS to check that the recipe is loaded properly. Check the
temperatures (all 5 zones) are stabilized at the set point (400°C for both
sintering recipes)
Start A Process Recipe
9.2.8
Press RUN to start the process recipe loaded previously. The tube
door will open and boats will come out.
9.2.9
Put on the face shield. After the boats move out completely. Load your wafers. The boats will remain out
for 20 minutes. If the boat start moving in and you have not finish loading
your wafers, press EVENT before the door closes, the boat will come out, and
you have another 20 minutes. (See Process Notes)
9.2.10
Press EVENT, and boats will start moving into the tube. When the
door closes completely, the temperature stabilization step starts. This is
normally a five minutes step optimized to recover the temperature gradient
caused by opening the door. Afterwards, the sintering/annealing step starts.
9.2.11
Once the anneal process is completed, furnace door will open
automatically and your wafers move out of the furnace. The door will remain
open for two hours. However, you should come back and unload your wafers as
soon as possible.
9.2.12
Press EVENT, and boats will start moving into the tube. When the
door closes completely, the recipe ends. There is no standby recipe for the
furnace.
9.2.13
Disable TYSTAR18 on the WAND.
10.0
Troubleshooting Guidelines
10.1
The tube is at one of the abort sequences (step AXXX) when you
come back to unload your wafers.
10.1.1
Cause: One of the process gas flows
was out of tolerance due to delivery system malfunction or gas cylinder getting
empty.
Solution: Press MENU, then enter DH. Press ENTER when
prompted for input. The whole process history for this run will be displayed.
Find the root cause for the abort and report on the WAND.
10.1.2 Cause: You
have not enabled the furnace. In this case, find a staff to restart the
process.
10.2
The tube is at special hold (step SHLD)
10.2.1
Cause: When the process hold
at SHLD, it indicates some serious system problem occurred, e.g. pump failure,
tube leakage, while process gases were flowing in the tube.
Solution: Report on the WAND or find a staff
immediately. Do not attempt to fix the situation yourself (including
super-users).
10.3
The door won’t open.
10.3.1 Cause: BOATIN is ON. Someone pressed the button by
mistake.
Solution: Press BOATIN to turn it OFF. Make sure BOATOUT
is ON.
10.3.2
Cause: System malfunction.
Boat loader has problem.
Solution: Report on WAND.
10.3.3
Cause: No nitrogen flow, and the
tube is not vented. On the display, N2 actual is 0, instead of 5000.
Solution: Report on WAND.
10.4
The FCS10 computer does not respond to the keypad input (computer
crash).
10.4.1 Cause: Use the Arrow Keys instead of the CLEAR to
erase the error, when enter, an alphanumeric inputs.
Solution: Report on WAND.
10.4.2 Cause: Press NEXTPAGE twice when loading a recipe
that requires multi-pages of inputs. Usually, this is caused by the old
keypads, not by the user.
Solution: Report on WAND.
11.0
Figures & Schematics
11.1 Front Control
Panel of the FCS10 Furnace Computer. Schematic view of Front Panel Display is shown below (Menu-Driven or ROP Display)
Tystar18 Front Panel Display
Figure 1 - Front
Panel Keypads
11.2 Furnace Status
Displayed on the FCS10 Front Panel (Idle state of the standby recipe)
FNC: DS – Display Process Status H2N2SINT.018
MODE: RUN END:
00.00.00 STEP: IDLE ST_TTG: 00.00.00
|
SETPT |
ACTUAL |
SIGNAL |
SETPT |
ACTUAL |
SIGNAL |
SETPT |
SIGNAL |
ACTUAL |
|
|
N2 O2 AR H2/N2 D2/N2 |
3000 G 0 G 0
G 0
G 0
G |
3000 0 0 0 0 |
TEMPL TEMPLC TEMPC TEMPPSC TEMPS RMPRATE TCUENA TCUID BOATSPD |
400.0 G 400.0 G 400.0 G 400.0 G 400.0 G 25.0 |
398.0 399.9 401.9 402.1 396.0 0 OFF 0 25.0 |
BOATOUT BOATIN SONIC EVENT |
OFF OFF OFF OFF |
DNTLK BPAUTO OUTLMT INLMT TUBEOT SCROT CABOT SHUNTRDY |
OFF OFF OFF ON OFF OFF OFF OFF |
FCS10 Furnace Computer Manu Commands
D - Display Sub-Menu
DE equipment status
DD file directory - Lists the recipes in
memory. (Same as DI DI in Tycom)
DH process history. In case of recipe abort,
error message can be found.
DR process steps in a recipe file. The system
will prompt you to select a specific recipe from memory.
DS process status that is continuously
updated.
DT temperature history
DE and DT should not be used.
R - Recipe Sub-Menu (password
protected except RL)
RE Allows one to edit recipes. See the Tystar Manual for instru