Universal Sputterer™
Sputter Run Log Plotter™
Analytical Graphic Software
© 2006
MAT-VAC Technology, Inc.
All Rights Reserved
Last Revision: V1.03 — 01 Nov 06
Introduction:
Interpriting the Graph:
Viewing Log Text:
Identifying Successful Recipes:
Printing:
Introduction:
As the MAT-VAC "Universal Sputterer"™ runs recipies a log is automatically generated. The log files are kept in the c:\logs directory and the filenames are of the form:
usSSSNNNNN.log
Where the SSS is the serial number of the machine and the NNNNN is the "Cook" number of that particular run. In this manner every run from every machine will produce a unique log ID so that logs from multiple machines can be saved in a common directory without risk of file name conflicts.
The logs are in ASCII format and can be viewed or edited with any editor such as WordPad™ or NotePad™. However the logs are necessarily verbose and plowing thru hundreds of log entries can become a chore, especially when what is of interest is the trend instead of some absolute number.
In order to make sense out of this abundance of data, the Sputter Run Log Plotter™ program has been developed to boil the data down into a meaningful form. Additionally the utility allows for printing of the data in a graphical form so that systems being used in a production environment can document their operation for production control purposes.
Each recipe run generates a unique log file. Within each file there can be any number of sputter events (a "sputter event" is sputtering on any available target in any mode {RF or DC} as well as RF Etching) and each event represents a separate graph from that particular log file.
The Sputter Run Log Plotter™ program is launched from the desktop as a separate application from the main "Universal Sputterer"™ program and can be run concurrently as it performs no actual I/O on it"s own.
Once the program is launched it will examine the contents of the c:\logs directory and place all of the files found into the Log File Selector. The program prompts the operator action with legends to the left of the selectors. Initially only the Log File Selector has a legend "First, select a log file:". Selecting the drop down shows a list of the available log files with the most recent at the top of the list:
 Having chosen a file from the Log File Selector the program will then scan that file for graphable events. Not all recipies will have plotable events. Certain test recipies that do not perform sputtering or etching will not have any data to plot. The list of available events (if any) will be placed into the Process Step Selector and the "Next, select one of the process steps:" prompting message will appear. Selecting the drop down shows a list of the available process steps:
Once the desired process step has been selected, the plot will be produced automatically and the Print button will enable and it"s prompting message "Finally, print the graph:" will appear.
The graph quite clearly captures the dynamics of ignition and sputtering. The advanced MAT-VAC system eliminates the need for igniters (and all of their associated "in vaco" equipment and electronics) by using the gas "burst" effect to insure clean plasma ignition. When the PLC is striking the plasma it turns on the gas simultaneously with the sputter power supply (RF or DC). The gas control system produces a short "burst" of gas, well above the setpoint when the gas valves are initially opened. This allows the plasma to easily ignite even at low process gas pressure settings (typically at or below 10mT). As the gas system stabilizes, the plasma remains lit and continues to operate at the setpoint pressure.
Another MAT-VAC advancement is target power ramping. This minimizes thermal shock to the targets by allowing the initial strike power to be low and then rise to the setpoint in a controlled manner. The ramping of the power is clearly shown in the red sputter power feedback trace and actual deposition scanning of the target by the carrier is delayed until both the gas and the power are stable.
Interpriting the Graph:
The contents of the graph is quite dense. There are three data tracks and full recipe annotation. Starting at the top of the graph we have the file name, step type, step number, sputter type and time stamp.
Below the title of the graph is the graph body. This is a rectangular grid area with horizontal divisions every 10% (the data being plotted is normalized to a percentage {%} of full scale). The divisions are labelled on the right edge of the graph area.
Within the body of the graph itself, there are quite a few data items. Starting at the top, each vertical sample line (no more than 20 per graph no matter what the duration of the sputter event) is labelled with it"s time stamp.
Below the time stamps on the left of the graph are the recipe settings. These fields are labelled in yellow and annotated in green. They include:
- Machine Name
- Recipe File Name and Step Description (if any)
- Scan speed
- Gas selections and setpoint
- Power setpoint
- Success or Abort notification
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Even with the recipe settings area on the right portion of the graph is the MAT-VAC Technology, Inc. logo.
The main body of the graph has three plots. They differ for DC and RF sputter events.
DC Sputter
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RF Sputter/Etch
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- Gas Feedback
- DC Power Feedback
- DC Voltage Feedback
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- Gas Feedback
- Forward RF Power Feedback
- Reverse RF Power Feedback
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As each plot line crosses a vertical marker, the value of the plot is labelled above the plot line. Depending on the length of the run, there can be additional data points between the vertical markers, but only the value of the data point at the marker will be shown to reduce the clutter on the plot.
The gas command setpoint is shown as a green horizontal long-dash line running the width of the plot. The numerical value of the gas command setpoint is printed in yellow at the left side of the plot just above the start of the green long-dash line.
There are two additional green horizontal short-dash lines, one above and one below the gas command setpoint line. These represent a reference band set by the PLC"s internal GASLIMT value. This value defines the ± tolerance used by the PLC in deriving the state of GASOOS signal (which triggers the Gas Out Of Spec abort error). The actual gas plot line will be in the same green as the setpoint and tolerance band, but will be thicker. The data point legends will be above the line in the same color as the plot itself.
The power command setpoint is shown as a red horizontal long-dash line running the width of the plot. The numerical value of the power command setpoint is printed in yellow at the left side of the plot just above the start of the red long-dash line.
There are two additional red horizontal short-dash lines, one above and one below the power command setpoint line. These represent ±3% reference band. These are just guidelines, they do not represent a limit within the system.
The power command plot is in red no matter if the power is DC or RF. The actual values are plotted as thicker lines with the data point legends above. The data point text will be in the same color as the plot itself.
The blue plot represents either the DC Voltage Feedback (DC sputter) or the RF Reverse Power Feedback (RF Sputter/Etch). The blue line does not have a setpoint or any tolerance band associated with it. The legends above the line will be expressed with the appropriate units symbol, Volts or Wwatts and the data point text will be in the same color as the plot itself.
Below the plot grid are the legends. These appear as either:
for DC sputter or:
for RF Sputter/Etch. The actual maximums for each plot depend on the specific power supplies installed in the system and may vary from those shown here.
Viewing Log Text:
Double clicking on the body of the graph will flip from the graphical representation of the data to the actual text of the log. Double clicking on the text of the log will restore the graphical image.
Identifying Successful Recipes:
A recipe that ran to completion without any errors on any sputter event will indicate success by the messages:
THIS RECIPE STEP WAS SUCCESSFUL!
THE ENTIRE RECIPE WAS SUCCESSFUL!
Since each step in a recipe is a separate event, it is possible for the given step in the recipe to be successful and yet the recipe as a whole, fail. This is indicated by the messages:
THIS RECIPE STEP WAS SUCCESSFUL!
THE ENTIRE RECIPE WAS ABORTED!
If you are examining the step that failed, the messages will appear as:
THIS RECIPE STEP WAS ABORTED!
THE ENTIRE RECIPE WAS ABORTED!
When a sputter event is aborted, the moment of the abort is indicated by a thick, solid, red vertical line. At the bottom of the line the abort message(s) from the log are displayed.
In this example a SAFETY E-STOP! has been detected, indicating that the Safe To Start (STS) relay has dropped out due to one or more of the following conditions:
- Loss of chamber vacuumCMBVAC
- Loss of Water Flow
- Safety Cover Opened
This indicates an instantaneous hardware shutdown of the power supplies external to the PC/PLC controls.
This is but one example of an abort message. Many other messages are possible including:
- Recipe Aborted due to Power Fault!
RF VSWR out of limit!
- Recipe Aborted due to Power Fault!
DC Out of spec for nn seconds...
DC Plasma Quenched!
- Recipe Aborted due to Power Fault!
Gas Out Of Spec for more than 30 seconds!
Printing:
When the appropriate plot has been generated, clicking the Print will display the printer selection dialog if a printer has been installed on the system PC. The number and description of the available print devices will vary. Once having selected the appropriate print device and clicking on the Print button, the output will be produced. The printout will be in landscape orientation and is suitable for attachment to a production report or log.
Only the graphical plot can be printed. If a copy of the log text is required the log file is ASCII and can be opened/viewed/printed with any editor including Wordpad™ or Notepad™. |
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