WaferSense® Auto Vibration Sensor (AVS) FAQ
CyberOptics Semiconductor provides answers to the most commonly asked questions about WaferSense AVS.
We are constantly adding questions and answers to our product FAQ section. If you don't find your product question/answer, please contact us.
Principles of Operation
Product Uses and Features
- What range of vibrations will AVS measure?
- What is the AVS resolution specification?
- What is the AVS operating temperature range?
- Is the AVS vacuum compatible?
- Can AVS communicate wirelessly from within closed chambers under vacuum?
- What types of tools will AVS operate in?
Maintenance and Repairs
- Will AVS need to be calibrated or serviced on a periodic basis?
- Is there a recommened field accuracy test?
- How long will the AVS battery last?
- How can I check that my AVS wafer is providing correct vibration data?
- What should I do if my WaferSense device is damaged?
VibeView™, VibeReview™ and Software
- What is the VibeView and VibeReview software?
- Does AVS have data logging?
- Can AVS logged data be exported to other analysis applications such as Microsoft Excel?
Interference, Contamination and Safety
- How does AVS communicate with the VibeView application?
- Is it safe to use Bluetooth in the fab?
- How do I safely handle the AVS vibration wafer?
- Will my AVS wafer outgas when subjected to high temperatures?
- Will my AVS wafer contribute to particulate contamination?
- How do I maintain the cleanliness of the AVS wafer?
Troubleshooting
- What if I receive the error message, "FTD2XX.DLL is missing"?
- What if my WaferSense wafer is not communicating with the WaferSense link box?
- What if the WaferSense device frequently looses the connection?
Principles of Operation
What is AVS used for?
AVS can be used to measure vibrations experienced by wafers during transport or processing. For example, a typical application for WaferSense AVS would be to measure the vibration experienced at a process stage and during operations that transport the wafer through the process tool.
How does AVS measure vibrations?
AVS uses three MEMS (microelectromechanical) to measure the acceleration of orthogonal axis of the wafer. Each of the three MEMS devices measures the differential capacitance of a moving proof mass placed between fixed electrode plates of opposite polarity. The capacitance changes in response to changes in acceleration. The differential capacitance of the three electrodes is measured by an analog-to-digital converter. Proprietary technology is used to accurately convert the MEMS readings to accelerations expressed in terms of earth’s gravity.
Product Uses and Features
What range of vibrations will AVS measure?
AVS measures vibrations in the range of -2 G to +2 G.
What is the AVS resolution specification?
AVS resolution is +/-0.01 G.
What is the AVS operating temperature range?
AVS will operate accurately at temperatures from 20ºC to 70ºC.
Is the AVS vacuum compatible?
ATS measures offsets to targets 6.5 mm – 45 mm below the teaching wafer.
Can AVS communicate wirelessly from within closed chambers under vacuum?
Yes. WaferSense devices are specifically designed to communicate out from closed tools and chambers.
What types of tools will AVS operate in?
Yes. AVS was designed to operate in all semiconductor tools. AVS is handled like a wafer and can be transported via tool automation to all tool and transport locations. Common examples of where AVS is used include:
- Diffusion
- FI
- OHT
- Metrology
Please contact technical support to request the latest information.
Maintenance and Repairs
Will AVS need to be calibrated or services on a periodic basis?
Yes. As with any measurement instrument used in a wafer fabrication plant, AVS requires periodic calibration to ensure continued conformance to specifications. We recommend that you return your AVS units to the factory annually for battery replacement, calibration and re-certification. Please contact technical support to make arrangements.
Is there a recommended field accuracy test?
No. We recommend that you return your AVS units to the factory annually for battery replacement, calibration and certification.
How long will the AVS battery last?
The AVS is powered by a rechargeable battery with a 10 year shelf life. Storage and/or operation of the AVS battery at temperatures higher than 80°C will decrease the amount of power that the battery can hold. The AVS battery temperature should never exceed 100°C. The battery is not user serviceable. It is replaced during the calibration service.
How can I check that my AVS wafer is providing correct vibration data?
Your sensor provides the most accurate inclination data within approximately 12 months from factory calibration. Your sensor's last calibration date is imprinted on a label affixed to the side of the raised electronics enclosure. Also accessing the "About Your AVS Wafer" option under the "Help" menu while VibeView software is running will provide this information.
If more than 12 months have passed since your sensor was last calibrated, we recommend you contact technical support to make arrangements to return your AVS device for factory calibration.
What should I do if my WaferSense device is damaged?
If you suspect misuse or damage to your WaferSense device, please contact technical support for help with returning your WaferSense device to the factory for repair and/or calibration service.
VibeView™, VibeReview™ and Software
What is VibeView and VibeReview software?
The VibeView software application monitors and records vibration information in real time. VibeReview lets you play back vibration log files recorded in VibeView.
Does AVS have data logging?
Yes. Whenever you want to record vibration data, in VibeView simply click on “START” in the “Record Data” section.
Can AVS logged data be exported to other analysis applications such as Microsoft Excel?
Yes, in VibeView -> Settings -> Options select “Record CSV files too” and a .CSV file will be created in addition to the .avsdata logged data file.
Interference, Contamination and Safety
How does AVS communicate with the VibeView application?
The AVS wafer employs Bluetooth communication technology to relay vibration data to a PC via the link box. Bluetooth communications use the 2.4 GHz frequency band.
Is it safe to use Bluetooth in the fab?
The WaferSense Link has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. We are unaware of any case where undesirable radio interference from or with other devices in the shared spectrum have been a problem’s with the WaferSense devices.
How do I safely handle the AVS vibration wafer?
The AVS wafer is much more durable than a silicon wafer. It is a sensitive electronic measurement instrument that should be handled gently. For example, please avoid dropping or impact with hard objects such as load port doors.
Will my AVS outgas when subjected to high temperatures?
No. Please contact technical support to request a copy of our outgas test report.
Will my AVS wafer contribute to particulate contamination?
No. Please contact technical support to request a copy of our particulate test report.
How do I maintain the cleanliness of the AVS wafer?
CyberOptics Semiconductor cleans each component of the AVS to semiconductor industry standards prior to assembling each AVS in a clean environment. To maintain this level of cleanliness, we recommend wiping the exterior of the device and the interior and exterior of the charging case with semiconductor-grade isopropyl alcohol.
Troubleshooting
What if I receive the error message, "FTD2XX.DLL is missing"?
The error message "FTD2XX.DLL is missing" has one of two possible causes:
- VibeView has been executed prior to plugging the link module into its USB cable.
- VibeView has been executed, but the driver for the link module has not been loaded.
Solution: Plug the link module into its USB cable and into the computer. Then run VibeView; you should not see the error message. If you still get the error message, then the driver for the link module is probably not loaded. Run the installation again.
What if my WaferSense wafer is not communicating with the WaferSense link box?
Make sure the power LED on the link module is on. The power LED on the link module will be lighted only if two things are true:
- The driver must be loaded.
- The USB cable must be connected to a powered UPS hub/port.
Loading the driver:
The driver is loaded by loading the software from the CD that accompanied the WaferSense device. The Pair status and Connection status led on both link module and WaferSense unit should be on (solid red). If not the units may need to be paired.
Pairing:
- Make sure the driver is loaded.
- Connect link module to powered UPS port. Do not start VibeView application until units are paired.
- Make sure green power LED is on.
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Press new pair button on right side of link module and hold for 10 seconds and then release. Pair status and connection status led should flash rapidly. Then the connection status led should go out and Pair led should continue flashing slowly. This indicates that the link is now searching for a WaferSense unit to pair with.
-
Now turn on the WaferSense ALS and Press new pair button on unit. Hold for 10 seconds and then release. The pair status and connection status led should flash rapidly. Then the connection status led should go out and Pair led should continue flashing slowly. It may take 20 second for the two units to finally Pair. When the connection is made both the Pair status and connection status led should be on (solid red). If the unit does not pair, power down WaferSense unit and repeat step 5.
- Once the units are pair you can start the WaferSense software application.
What if the WaferSense device frequently looses the connection?
Possible Causes:
PC Battery Power Options:
We have discovered that depending on the PC and/or the PC’s battery resource settings, there may be occasions where the PC will take a few milliseconds and ‘query’ the USB ports and looks to conserve power, especially if the PC battery power is running low. It interrogates USB ports and turns them off then back on to see if they are connected to anything. When this happens the WaferSense will likely loose connectivity and it could take up to 40 seconds for the connectivity to be reestablished.
Troubleshooting and/or Solution:
- Try running the PC with AC power to the PC.
- Go into the PC's power options and set the PC to "Highest System Performance: and see if this resolves the issue when the PC is running on battery power.
- Run AVS and Laptop on fully charged battery.
Bad or Flaky USB Port.
Troubleshooting and/or Solution:
- Try a different USB port.
- Verify that the USB cable is tightly connected.
- Try a different PC.
Proximity and/or location of Link Box to WaferSense wafer.
Troubleshooting and/or Solution:
- Move the Linkbox physically closer to the location of the AVS wafer.
- If a chamber windows exist or other tool location were the AVS single might transmit out of the tool better, try moving the physical location of the Link. Sometimes just moving the link to different locations resolves connectivity issues.
Issues with WaferSense wafer or WaferSense link box or AVS wafer.
Troubleshooting and/or Solution:
- Swap link – does the problem follow the link?
- Swap WaferSense wafer – does the problem follow the wafer?