WaferSense® Auto Leveling System (ALS2) and Auto Leveling System with Vertical (ALS2V) FAQ

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CyberOptics Semiconductor provides answers to the most commonly asked questions about WaferSense ALS2/ALS2V.

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

  1. What is WaferSense ALS2 used for?
  2. What is the reference plane used for the ALS2V inclination measurements?
  3. What is the difference between ALS and ALS2?
  4. How does ALS2V meaure vertical and horizontal inclination?

Product Uses and Features

  1. What are the ALS2V horizontal and vertical inclination ranges and corresponding accuracy specifications?
  2. What is the ALS2V resolution specifiction?
  3. What is the ALS2 operating temperature range?
  4. Is ALS2V vacuum compatible?
  5. Can ALS2V communicate wirelessly from within closed chambers under vacuum?
  6. What types of tools will ALS2/ALS2V operate int?

Maintenance and Repairs

  1. Will ALS2/ALS2V need to be calibrated or serviced on a periodic basis?
  2. How long with the ALS2/ALS2V battery last?
  3. How can I check that my sensor is providing correct inclination data?
  4. What should I do if my WaferSense device is damaged?
  5. What is offered as part of the ALS2/ALS2V calibration service?

LevelView™, LevelReview™ and Software

  1. What is the LevelView and LevelReview software?
  2. Does ALS2/ALS2V have data logging?
  3. Can ALS2/ALS2V logged data be exported to other analysis applications such as Microsoft Excel?

Interference, Contamination and Safety

  1. How does the ALS2/ALS2V communicate with the Levelview application?
  2. Is it safe to use Bluetooth in the fab?
  3. How do I safely handle the WaferSense wafer?
  4. Will my Wafersense wafer outgas when subjected to high temperatures?
  5. Will my WaferSense wafer contribute to particulate contamination?
  6. How do I maintain the cleanliness of the WaferSense wafer?

Troubleshooting

  1. What if I receive the error message, "FTD2XX.DLL is missing"?
  2. What if my WaferSense wafer is not communicating with the WaferSense link box?
  3. What if the WaferSense device frequently looses the connection?

Principles of Operation

What is WaferSense ALS2 used for?
The ALS2 vertical and horizontal leveling wafer is used to measure and adjust the inclination of cassettes, FOUPs, end effectors, load locks, transfer pins, process chamber chambers pedestals to full characterize all fabs production and transport equipment.  

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What is the reference plane used for the ALS2V inclination measurements?

By default, the sensor indicates degrees out of level, in pitch and roll, with respect to a plane perpendicular to the direction of the Earth's gravitational force (absolute measurement). A different plane could be specified via LevelView™ software and used to reference inclination data (relative measurement).

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What is the difference between ALS and ALS2?
The new ALS2/ALS2V versions of our WaferSense leveling wafer has many advantages:

ALS2V Feature/Enhancement ALS2 Benefit
Thinner 6.3mm design Goes in more tools and goes more places automatically
New carbon fiber composite housing Thinner, cleaner and tougher. Can be clamped by Electro-Static-Chucks
Vertical inclination measurements Enables vertical ion implant and wet station alignments
Greater horizontal operating range Measures more steeply tilted pedestals especially in the Copper plating area
LevelView 2.0 streamlined application GUI Easier to use GUI. Tablet PC friendly
Slope and polar display options available with LevelView 2.0 More output options for ease of use

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How does ALS2V measure vertical and horizontal inclination?
ALS2V uses three MEMS (microelectromechanical) to measure inclination in the X, Y, and Z axis. ALS2V can measure inclination relative to earth’s gravity or relative to a reference plane.

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Product Uses and Features

What are the ALS2V horizontal and vertical inclination ranges and corresponding accuracy specifications?
ALS2 horizontal inclination accuracy is +/-0.03 degrees within a range of +/-7.0 degrees. ALS2 vertical inclination accuracy is +/-0.05 degrees within a range of +/-50.0 degrees.

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What is the ALS2/ALSV resolution specification?
ALS2/ALS2V horizontal resolution accuracy is +/-0.002 degrees within a range of +/-14.0 degrees. ALS2V vertical inclination resolution is +/-0.01 degrees within a range of +/-50.0 degrees.

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What is the ALS2/ALSV operating temperature?

ALS2/ALS2V will operate accurately at temperatures from 20ºC to 70ºC.

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Is ALS2/ALS2V vacuum compatible?
Yes. The ALS2 device can be used under pressures ranging from atmospheric to ultra-high vacuum.

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Can ALS2/ALS2V communicate wirelessly from within closed chambers under vacuum?
Yes. WaferSense devices are specifically designed to communicate out from sealed tools and closed vacuum chambers.

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What types of tools will ALS2/ALS2V operate in?

Yes. ALS2/ALS2V was designed to operate in all semiconductor tools. ALSS2 is handled like a wafer and can be transported via tool automation to all tool and transport locations. Common examples of where ALS2 is used include:

  • Diffusion
  • FI
  • OHT
  • Metrology
  • CVD/PVD/Etch
  • Photo

Please contact technical support to request the latest information.

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Maintenance and Repairs

Will ALS2/ALS2V need to be calibrated or serviced on a periodic basis?
Yes. As with any measurement instrument used in a wafer fabrication plant, ALS2 requires periodic calibration to ensure continued conformance to specifications. We recommend that you return your ALS2 units to the factory annually for battery replacement, calibration and re-certification. Please contact technical support to make arrangements.

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How long will the ALS2 battery last?
The ALS2 is powered by a rechargeable battery with a 10 year shelf life. Storage and/or operation of the ALS2 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. Typically a well functioning ALS2 battery will last 4 to 5 hours when fully charged.

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How can I check that my sensor is providing correct inclination 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 LevelView" option under the "Help" menu while LevelView 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 WaferSense device for factory calibration. If you only take absolute measurements and have access to a flat, level granite slab that is free of vibrations, you can easily verify the functionality of your unit by measuring the inclination of this test surface. If the slab is flat and level, ALS should indicate 0° inclination both in pitch and in roll.

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What should I do if my Wafersense unit 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.

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What is offered as part of the ALS2/ALS2V calibration service?
CyberOptics Semiconductor is the only facility authorized to perform verification of ALS calibration, replacement of ALS battery, and repairs for product and parts. The calibration service offered for ALS includes replacing the battery, verifying sensor accuracy, and issuing calibration information to users. When appropriate, recommendations are made for remedial actions for sensors that do not perform as specified.

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LevelView™, LevelReview™ and Software

What is LevelView and LevelReview software?
The LevelView software application monitors and records inclination information in real time. LevelReview application lets you play back LevelView inclination log files.

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Does ALS2/ALS2V have data logging?

Yes. This is done by selecting “Log a Reading Now” in LevelView.

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Can ALS2/ALS2V logged data be exported to other analysis application such as Microsoft Excel?

Yes. All LevelView logged data is saved in a CSV file and can be exported to any application that supports CVS file format.

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Interference, Contamination and Safety

How does the ALS2/ALS2V wafer communicate with the LevelView applicaiton?
The ALS2 wafer employs Bluetooth communication technology to relay X, Y and Z inclination data to a PC via the link box. Bluetooth communications use the 2.4 GHz frequency band.

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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.

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How do I safely handle the WaferSense wafer?
A WaferSense 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.

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Will my WaferSense wafer outgas when subjected to high temperatures?
No. Please contact technical support to request a copy of our outgas test report.

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Will my WaferSense wafer contribute to particulate contamination?
No. Please contact technical support to request a copy of our particulate test report.

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How do I maintain the cleanliness of the WaferSense wafer?
CyberOptics Semiconductor cleans each component of the ALS2 to semiconductor industry standards prior to assembling 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.

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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:

  1. LevelView has been executed prior to plugging the link module into its USB cable.

  2. LevelView 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 LevelView; 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.

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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:

  1. The driver must be loaded.

  2. 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:

  1. Make sure the driver is loaded.

  2. Connect link module to powered UPS port. Do not start LevelView application until units are paired.

  3. Make sure green power LED is on.

  4. 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.

  5. 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.

  6. Once the units are pair you can start the WaferSense software application.

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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 ALSS2/ALS2V 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 ALS2/ALS2V wafer.

  • If a chamber windows exist or other tool location were the ALS2/ALS2V 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 ALS2/ALS2V wafer.

Troubleshooting and/or Solution:

  • Swap link – does the problem follow the link?
  • Swap WaferSense wafer – does the problem follow the wafer?

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