Specific Process Knowledge/Thermal Process/Oxidation/Standard oxidation recipes
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The oxidation furnaces in the cleanroom are being used for dry and wet oxidation of silicon wafers.
On this page the steps in the standard oxidation recipes on the furnaces will be listet.
Dry oxidation can be done in the these furnaces:
- A1 Boron Drive-in and Pre-dep furnace
- A2 Gate Oxide furnace
- A3 Phosphorus Pre-dep furnace
- C1 Anneal-Oxide furnace
- C3 Anneal-Bond furnace
- Multipurpose Anneal furnace
The dry oxidation recipes in the A- and C-stack furnaces are very similar and will be described on this page.
There are no standard recipes on the Multipurpose Anneal furnace, so no oxidation recipes will be described here.
Wet oxidation can be done in these furnaces:
- A1 Boron Drive-in and Pre-dep furnace
- A3 Phosphorus Pre-dep furnace
- C1 Anneal-Oxide furnace
- C2 III-V Oxidation furnace
- C3 Anneal-Bond furnace
The wet oxidation recipes in the A-stack, C1 and C3 furnaces are very similar.
Wet oxidation of III-V sample in the C2 furnace is described here:
General recipe remarks:
The oxidation temperature is fixed in each recipe. The temperature can be seen in the recipe name, e.g. "DRY1000" for dry oxidation at 1000 C and "WET1100" for wet oxidation at 1100 C.
The oxidation and annealing times are variable commands in oxidation recipe. It means that these can be changed by the users.
The oxid thickness is defined by the oxidation time. Wet oxidation is much faster then dry oxidation. It is maximum allowed to grow 300 nm of dry oxide and 3 um of wet oxidation.
The annealing improves... The standard annealing time is 20 minutes, but it is possible to change the time.
Dry oxidation recipe steps
00 STANDBY
Message: "Standby"
When the furnace is not in use, and when a recipe is selected, this will be the active step.
If a recipe is aborted, it will jump to the STANDBY step.
The furnace is kept closed and clean:
- Standby temperature: 700 oC
- N2 flow: 3 SLM
- O2 flow: 0 SLM
The user has to press "Start" (on the touch screen or furnace computer) to start the recipe.
01 LM-LOCK
Message: "Standby"
The recipe can only continue, if a user is logged on in LabManager
02 OPEN
Message: "Boat moving"
The furnace opens
03 LOAD WAFERS
Message: "Load wafers
When the furnace is open, the user can load wafers in the furnace.
The user has to press "Start" (on the touch screen) or "Continue" (on the furnace computer) to close the furnace.
04 CLOSE
Message: "Boat moving"
The furnace is closing.
05 HEAT UP
Message: "Heat-up"
The furnace is heating up to the temperature defined in the recipe (usually 800-1150 oC.
The recipe will continue to the next step, when the temperature of center heating zone (zone 2) reaches the right temperature.
06 OXIDATION
Message: "Dry oxidation"
The dry oxidation is started O2 flow: 5 SLM N2 flow: 0 SLM
The oxidation time is a variable command.
has been defined by the user. The oxidation time can be changed, until the oxidation step is started.
07 ANNEAL
Message: "Anneals/Dens"
08 COOL DOWN
Message: "Cool-down"
The furnace is cooling down to 700 oC (the standby temperature)
09 UNLOAD WAFERS
Message: "Unload wafers"
The user has to press "Start" (on the touch screen) or "Continue" (on the furnace computer) to close the furnace
10 OPEN
Message: "Open"
The furnace opens.
11 UNLOAD
Message: "Unload wafers"
When the furnace is open, the wafer can be unloaded. Be aware of, that the wafers are very hot, so they have to cool down for about five minutes
When the wafers are unloaded, the user has to press "Start" (on the touch screen) or "Continue" (on the furnace computer) to close the furnace. The recipe then jumps to the STANDBY step, and the user can leave the furnace, after it has closed.
If a recipe is aborted
The standard annealing time is 20 minutes, but users can change the time. The annealing time can be changed, until the annealing step is started.