Unaxis PECVD

Trainers

A PECVD (plasma enhanced chemical vapor deposition) reacts gases in a RF (radio frequency) induced plasma to deposit materials such as silicon dioxide and silicon nitride.
This PECVD has a one chamber.  A single chamber is used for both silicon nitride and silicon oxide deposition.

Machine Specifications
The Unaxis PECVD can process a wide range of sample sizes. The number of samples depends on the size of the samples.  A typical run can process anywhere from one to four 4" wafers. Typical deposition rates range from 100 Å/s to 400 Å/s.

Typical Processes
 Silicon Dioxide Deposition
 Silicon Nitride Deposition

Operating Instructions
I. Loading a Sample

1. Login
2. Press the ON button at the bottom of the screen.
3. Press the STANDBY button at the bottom of the screen.
4. Highlight Utilities, Vent.
5. Once the chamber is vented, lift the chamber door.
6. Load sample into the center of the chamber.

II. Operating
1. Highlight Process, Load Recipe.
2. Press the READY button at the bottom of the screen.
3. After READY parameters have been applied, press the RUN button at the bottom of the screen.

III. Unloading
1. After the process is over, press the STANDBY button at the bottom of the screen.
2. Highlight Utilities, Vent
3. Once the chamber is vented, lift the chamber door.
4. Unload sample from the chamber.
5. Highlight Utilities, Pump Chamber.
6. Highlight Utilities, Logout.

IV.  Creating a Recipe
Overview
In general, your recipe should have four steps: an initial step, two process steps, and an end step. The initial step evacuates the chamber, removing the air inside, and brings the chamber to the process temperature. The first process step is a gas purge step, and it also sets the process pressure.  It allows the chamber pressure and gas flows time to stabilize. Because the RF power is off, no processing will actually take place during this step. The second process step performs the process.

Instructions
From the Process menu, choose Build to create a new recipe or Edit to edit an existing one.  A list of the recipe steps will be displayed on the right side of the screen. To edit a step, double click on it. To create a new step, select the step that will go after the new step and click the appropriate button for the type of step you want at the bottom of the screen.

Initial Step
All recipes start with an initial step. This step will evacuate the chamber and bring the chamber to the desired operating temperature.  Set the pressure to 30mTorr and set the time to 30 seconds. This will cause the system to evacuate as much air from the chamber as possible before starting the process. Do not attempt to use pressure setpoints below 30mTorr. The chamber will be evacuated as much as possible regardless of the setpoint.
Set the temperature to your desired process temperature.  Note that the temperature is measured in degree Celsius.  You may describe your recipe in the Description box.  The first few words will be displayed by the file name when you are loading your recipe.

Process Step
You will usually want two process steps. They should be identical with a few exceptions. The process step dialog box has five major areas: time, temperature, pressure, gas flow, and power.

Time
The first process step's "Terminate by" time should be set to "Fixed Time" This step will be used to stabilize the chamber conditions. The time for this step is not critical, but 30 seconds is good.  The second step will actually perform your process. If you set it's "Terminate by" time to "Variable Time" you will be prompted for the process time each time you run your recipe. This is usually more convenient than editing the recipe each time. However, you can set the process to "Fixed Time" and set the time here if prefer.

Temperature
Set the temperature to you desired process temperature for both process steps.  Note that this should probably be the same as the temperature set in the initial step. 

Pressure
Set the pressure to the process pressure you want for both process steps. If you are operating the RIE at lower pressures you will need to set the pump to the turbo pump. Otherwise use the mechanical pump. The process pressure is measured in millitorr.

Gas Flow
Set the flow rate for each gas here. The flow rates are given in sccm (standard cm3/min). The flow rates should be the same for both process steps.

Power
Leave the power set to zero in the first step. Set it to the power you want for your process in the second process step.  Please do not exceed 400 W.

End Step
All recipes have an end step that evacuates the chamber. Set the pressure to 30 millitorr and set the time to sixty seconds. The automatic vent feature does not work properly and should not be used. When you modify a process, you only change the copy on the disk. If the process is already loaded, you will need to reload it for your changes to be reflected.

Don'ts
Please do not stick your hand into the chamber.  The area is very hot.
Please do not try to open the chamber door while the system is running.
Please do not try to run the process if the chamber door is open.

V. Conclusion

After watching this training video, you should know how to:

Load a sample
Run a recipe
Unload a sample
Program a recipe

If you have any questions, please direct them to the trainer of this equipment.  Please do not ask Mohammed.