Tystar Oxidation & Anneal Furnace Operation - Login | Nanolab, UCLA

oxidations. Offsets may change slightly from time to time or when the furnace tube is changed.
Consult the log book recipe sheet for latest offsets. Use the preview mode to verify offsets are
correct in the desired recipe. Change them to the log book value if necessary.
When the furnace is opened it is normal for the front zone and center zone to cool off while
the rear zone overheats. Temperature recovery may take up to an hour and these times are
already built into the recipes. Keep in mind that the furnace can be ramped at ~10°C/min while
cooling will be less than 5 °C/min. It is not desirable then to overheat the furnaces.
These furnaces are meant to control between 450-1100°C. Do NOT process outside of
these limits. Additionally, all wet oxide runs must be 800°C - 1100°C.
The center zone should be stabilized (0 on the deviation meter) BEFORE attempting to adjust
the end zones (via TempL or TempS) since the end zones are "slaved" to the center zone.
FURNACE LOADING & UNLOADING:
Although it is possible to incorporate load and unload steps into a recipe, the Nanolab prefers
to Load and Unload from Recipe 0 to avoid any possibility of the furnace being open for
prolonged times. There are 2 quartz boats kept in the tube at all times. For 25 wafers or less,
always use the front boat for best uniformity. (Wafers near the rear will see a higher
temperature during wet oxidations due to the torch temperature.) Dummy wafers are not
required, but a clean bare silicon monitor should be run with your wafers to obtain oxide
thickness. Position of these boats on the cantilever is critical; by using the front boat only and
making sure it just touches the rear boat when you load it, you will guarantee proper boat
placement. Face wafers forward with flats facing up. (Although the process does not require
this, it will help us to troubleshoot problems in the future.) To Load your wafers (after fulfilling
all of the aforementioned requirements):
LOADING:
1 Push PROGRAM button (light comes on), 0, ENTER
2 Verify N2 flow is 3500 cc (3.5L/min); change it if necessary
3 Verify Temperature is 800°C with AUTO TEMP on. Change it if necessary.
4 Verify H2H/O2, H2L/N2, O2 Hi and O2 Lo are off.
5 Verify LOAD light is OFF; push button if it is on.
6 Turn on UNLOAD light by pushing UNLOAD button.
7 Cantilever should slowly come out. The speed is determined by lab management
and should be less than 9 inches/minute. Too fast a speed can result in wafer
warpage or slip.
8 When the cantilever is fully extended, use the steel fork to unload the front quartz
boat onto the quartz sled (the steel bench may be used if the sled is not available).
Do NOT set the hot boat on a wipe or anything else which may melt.
9 Load your cleaned substrates (3 or 4 inch) so that each wafer sits in its own slot and
is perpendicular to the boat. Up to 25 wafers may be loaded in this way. Keep all of
the wafer facing forwards with flats all aligned upwards.
10 Using the steel fork, carefully place the boat back onto the cantilever rods so that it
is in front of and just touches the rear boat. Make sure the boat is centered on the
rods.
11 Turn off UNLOAD by pushing button (you must still be in PROGRAM mode.)
12 Turn on LOAD by pressing LOAD button. Light comes on and cantilever slowly
goes into the furnace tube.
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