INFICON Guardian EIES Controller - Manual (Page 135)

6 - 11
IP
N 07
4-
51
7-
P1
D
Guardian Co-Deposition Controller Operating Manual
6.4.6 Cross Channel Calibration
The EIES detector may detect optical emission from background gases or other
materials. This is particularly true if the emission wavelengths of other materials are
near the wavelength of the material being measured. To compensate for this effect,
you need to measure and subtract the interfering (cross channel) rate(s).
In the EIES software, create a codeposition layer for the materials to be calibrated.
Show the channel's Edit Layer dialog box, Film Cal. tab. With no deposition on the
selected channel, start deposition on the interfering channel. When the interfering
channel rate stabilizes, calculate the percent of the interfering channel's rate
reading that shows in the channel you are calibrating. Select the interfering channel
in the First xChan drop-down menu and enter the percent value in the First
xChan% cell. You can repeat this procedure with a second, third, or fourth
interfering channel.
For example, let's say that you are codepositing copper (Cu) on Channel 1 and
cadmium (Cd) on channel 2. The wavelength for Cu is 3261, for Cd the wavelength
is 3247. It is unlikely that either of these filters will adequately reject the other
material's signal.
While not depositing copper on channel 1, start depositing cadmium on channel 2,
near the desired rate. Let's say the channel 2 rate (Cd) is 1 Å/s, and with no copper
being deposited channel 1 measures .1 Å/s. Then for channel 1, you would enter
First xChan = 2 and xChan% = 10. This will calibrate the channel 1 reading to show
0 Å/s, the true Cu reading.
Repeat this procedure while depositing Cu on channel 1, and no Cd deposition on
channel 2. Assume that the channel 1 rate (Cu) is 20 Å/s and channel 2 measures
1 Å/s. On the channel 2 Edit Layer dialog box, enter 1st xChan = 1 and
1st xChan% = 5%.
This procedure can compensate for three other materials. In each case, deposit no
material on the channel you are calibrating, and calibrate for the other channels.
6.5 Loop Tuning
This section will help you adjust your control loop PID parameters to achieve a
stable deposition process. Keep in mind that there is no "best" way to determine
PID parameters, and no one set of settings that are "best."
Setup System Parameters: Be sure that the output Full Scale voltage and crystal
Min/Max Frequency parameters are accurate for your system. If the correct Tooling
parameters have not already been previously determined, set them to 100% for
now. An Update rate of 4 Hz is also a good starting point. Simulate should be OFF.
Allow a one hour warmup for the PMT Detector Module to achieve optimum
stability.