WaferSense® Auto Leveling System (ALS) and
Auto Leveling System Reticle (ALSR) FAQ
CyberOptics Semiconductor provides answers to the most commonly asked questions about WaferSense ALSR.
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
- How is inclination measured by the ALS device?
- What is the reference plane used for the ALS inclination measurements?
Product Uses and Features
- What form factors can ALS have?
- What materials are used in the construction of ALS devices?
- How do I receive inclination measurements from my ALS device?
- Can two ALS devices be used with the same link?
- Can I use my ALS device for measuring inclination of robot arms?
- Can I use my ALS device to measure inclination of wafer hand-offs inside my equipment?
- Can I measure other phenomena, such as vibrations or acceleration, with ALS?
- Can I use the ALS device at elevated temperatures?
- Can I use the ALS device at low pressures (vacuum)?
- How do I charge the ALS device?
Maintenance and Repairs
- How can I check that my sensor is providing correct inclination data?
- What is offered as part of the ALS calibration service?
- What options do I have if my ALS device is damaged?
LevelView and Software
- How do I log inclination data I measure with the ALS device?
- What format will be used to store my data?
Interference, Contamination and Safety
- Does the ALS device emit RF?
- How do I safely handle the ALS device?
- Will my ALS device outgas when subject to high temperatures?
- Will my ALS device contribute to particulate contamination?
- Will my ALS device contribute to metal contamination?
- How do I maintain the cleanliness of the ALS unit?
Principles of Operation
How is inclination measured by the ALS device?
The ALS device employs two electrolytic inclinometers mounted at a right angle to each other. Voltage output by each inclinometer is converted into pitch and roll inclination data.
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What is the reference plane used for the ALS 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).
Product Uses and Features
What form factors can ALS have?
The WaferSense ALS product line includes wafer-like and reticle-like inclination measuring devices. The wafer-like devices are available in three sizes: 150 mm (6"), 200 mm (8") and 300 mm (12"). The reticle-like devices are available in one size: 150 mm (6").
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What materials are used in the construction of ALS devices?
All WaferSense ALS devices are made of aluminum (main body) with a polycarbonate label. Wafer-like devices are available in either electroless-nickel plated or black anodized finish. Reticle-like devices are available in black anodized finish.
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How do I receive inclination measurements from my ALS device?
Inclination data is transmitted to a computer via the wireless link box connected to a USB port. Each ALS sensor is paired and will communicate with a wireless link box via the Bluetooth communication protocol. This protocol employs radio communications in a frequency band around 2.4 GHz.
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Can two ALS devices be used with the same link?
Yes. The Bluetooth communication protocol establishes a unique channel between two devices. While both ALS devices and link boxes can be synchronized or re-synchronized for communications in the field, the link box will only receive data from one ALS device at a time. Neither the link nor the sensor will communicate with any other Bluetooth-enabled device.
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Can I use my ALS device for measuring inclination of robot arms?
Yes. The wafer-like form factor allows the ALS device to be handled as a wafer by a variety of robot arms.
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Can I use my ALS device to measure inclination of wafer hand-offs inside my equipment?
Yes. The wafer-like form factor allows the ALS device to be picked up from a carrier (e.g. cassette or FOUP) with a robot arm, placed on an aligning station, and then circulated inside the semiconductor equipment as a wafer. Load locks and process chambers accommodate the ALS device well, which allows for real-time measurements and adjustments if needed.
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Can I measure other phenomena, such as vibrations or acceleration, with ALS?
No. ALS was designed to measure pitch and roll inclinations based on a reference plane. ALS cannot measure vibrations directly; however, you might observe during use that the device detects changes in the inclination of a plane as a result of vibration. The electrolytic inclinometers used are not adequate for measuring acceleration either.
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Can I use the ALS device at elevated temperatures?
Yes. The ALS device provides the most accurate inclination measurements at temperatures between 20°C and 30°C. However, the device will operate safely, with a slightly reduced accuracy, when exposed to temperatures of up to 70°C.
All measurements are carefully temperature-compensated so changes in internal sensor temperature do not affect the measured inclination data. Exposing ALS to temperatures higher than 70°C for extended periods of time will irreversibly damage the electronics within the device enclosure.
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Can I use the ALS device at low pressures (vacuum)?
Yes. The ALS device can be safely used under pressures ranging from atmospheric to 10-6 Torr.
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How do I charge the ALS device?
A transparent clamshell-type case is provided with each ALS device to protect it in transit and to aid in charging the battery. Simply return the device to its case and secure it with the locking bolt. Next connect the case with an electrical outlet via the charging adaptor provided. Although the battery takes a total of two hours to fully charge, 80% of the battery charge will be available within the first hour.
Maintenance and Repairs
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 ALS 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.
However, if you suspect misuse or damage, CyberOptics Semiconductor can verify, upon request, the accuracy of your unit over the entire operating range of the device. Please contact technical support for help with returning your ALS device to the factory for calibration service.
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What is offered as part of the ALS 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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What options do I have if my ALS device is damaged?
It is possible and practical to replace most of the electronic components contained in the ALS device enclosure, except for the electrolytic inclinometers. Damage to the electrolytic inclinometers or to the integrity of the ALS device metal housing is irreparable. In this case you need to obtain a replacement sensor.
LevelView and Software
How do I log inclination data I measure with the ALS device?
The LevelView software provided with ALS offers two options to log inclination data measured by the device: single data point and continuous. Switching between the two is easy by selecting the appropriate checkbox and specifying the interval, which you can set for once every second to once every 60 minutes.
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What format will be used to store my data?
Data logged with LevelView can be retrieved from the default CSV (comma-seperated values). Microsoft Excel can be used to display these data and process them to distinguish trends or other information pertinent to inclination. LevelView can be used to retrieve previously logged data in graphic format by toggling between real-time display and logged data (use upper left corner button and notice connection status icon and log reading icon toggle).
Interference, Contamination and Safety
Does the ALS device emit RF?
Yes. The sensor employs the Bluetooth communication protocol to relay inclination data to a laptop via the link box. Bluetooth communications use the 2.4 GHz frequency band.
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How do I safely handle the ALS device?
The ALS device is an electronic measurement instrument that needs to be handled as any other electronic device. For example, please avoid impact with hard objects, especially those that compromise the flat supporting surface of the device.
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Will my ALS device outgas when subject to high temperatures?
No. Please contact technical support for a test report.
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Will my ALS device contribute to particulate contamination?
No. Please contact technical support for a test report.
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Will my ALS device contribute to metal contamination?
No. Please contact technical support for a test report.
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How do I maintain the cleanliness of the ALS unit?
CyberOptics Semiconductor has made every effort to clean the ALS leveling sensor during manufacturing. To continue maintaining this level of cleanliness, we recommend wiping the exterior of the device and the interior and exterior of the charging case with isopropyl alcohol or a mild detergent solution. ALS cannot withstand a full immersion in a cleaning solution or contact with strong acid solutions.