WaferSense™ Auto Gapping System (AGS) FAQ
CyberOptics Semiconductor provides answers to the most commonly asked questions about WaferSense AGS.
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 gaps will AGS measure?
- What is the AGS accuracy specification?
- What is the AGS operating temperature range?
- Is AGS vacuum compatible?
- What types of chambers will AGS operate in?
Maintenance and Repairs
- Will AGS need to be calibrated or serviced on a periodic basis?
- Is there a recommended field accuracy test?
- How long will the AGS battery last?
GapView™ and Software
Interference, Contamination and Safety
Principles of Operation
How does AGS measure gaps?
Capacitance is inversely proportional to the distance separating two plates. AGS measures the capacitance between plates on the top surface of the AGS and a “plate” composed of the showerhead. A microcomputer inside the AGS converts the capacitance measurement into a gap measurement using stored calibration data and real-time sensor temperature data.
How does AGS measure parallelism?
Two surfaces are parallel when the distance separating them is constant. AGS displays three gaps to the user. When the three gaps are all the same within a user specified tolerance, the surfaces are parallel.
Product Uses and Features
What range of gaps will AGS measure?
The AGS is designed to measure gaps from 9mm to 20mm (0.35” to 0.79”).
What is the AGS accuracy specification?
AGS parallelisim accuracy is 0.025mm (±0.001”) and gap accuracy is 0.25mm (±0.01”) with a gap of 15mm (0.6").
What is the AGS operating temperature range?
AGS will operate accurately at temperatures from 20ºC to 80ºC.
Is AGS vacuum compatible?
Yes. The AGS device can be used under pressures ranging from atmospheric to ultra-high vacuum.
What types of chambers will AGS operate in?
AGS was designed to operate in semiconductor tools with parallel plates where the top plate is a conductor. Examples are:
- Applied Producer PECVD
- Novellus Vector
- ASM Eagle 12
AGS may provide useful information about other chambers. Please contact technical support to request the latest information.
Maintenance and Repairs
Will AGS need to be calibrated or serviced on a periodic basis?
Yes. As with any measurement instrument used in a wafer fabrication plant, AGS requires periodic calibration to ensure continued conformance to specifications. We recommend that you return your AGS 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 AGS units to the factory annually for battery replacement, calibration and certification. Of course, you may place the AGS in a known gap to verify the measurement.
How long will the AGS battery last?
The AGS is powered by a rechargeable battery with a 10 year shelf life. The battery is capable of storing at least 80% of its original power after 500 full discharge-recharge cycles. Storage and/or operation of the AGS battery at temperatures higher than 80°C will decrease the amount of power that the battery can hold. The AGS battery temperature should never exceed 100°C. The battery is not user serviceable. It is replaced during the calibration service.
GapView™ and Software
Does AGS have data logging?
Yes. Whenever you want to log a reading, simply click on “Log a Reading.” Any number of readings can be logged to a CSV (comma-separated value) file in that manner.
Interference, Contamination and Safety
How do I maintain the cleanliness of the AGS wafer?
CyberOptics Semiconductor cleans each component of the AGS to semiconductor industry standards prior to assembling each AGS 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.