AMC Cleanroom Monitoring for Inorganic Gases

AMC Cleanroom Monitoring for Inorganic Gases

Analytical data that improves yield with early warning of contamination events

SI2000 Series Analyzers

  • Real time AMC monitoring in cleanrooms,FOUP and FAB Equipment
  • Fast, continuous analysis in seconds
  • Virtuall no downtime or consumables cost
  • No field calibrations required, verify with single span gas annually

Yield declines and process upsets due to airborne molecular contamination (AMC) have been well documented. Analytical instruments that measure NH₃, HF, and HCl at ppb levels can have long-term drift in the baseline measurement and require frequent re-calibration resulting in significant downtime for the production lines. Also, due to the “sticky” nature of NH₃ and reactivity of HF and HCl, these gases are easily adsorbed to a variety of materials, including stainless steel, the typical material used for the construction of gas-handling components and tubing. The measured concentration and speed of response for the analyzer is dependent on the subsequent desorption, which is dependent on humidity and temperature. These restrictions on speed of response for the critical nature of these kinds of gas measurements have long been a significant restriction on providing true real-time process data for inorganic AMC monitoring in all Semiconductor applications.

Cavity ring-down spectroscopy (CRDS) offers significant advantages compared with incumbent AMC measurement techniques, such as ion-mobility spectrometry (IMS) and ion chromatography. Both legacy techniques have traditionally been used to monitor inorganic gases such NH₃, HF and HCl in cleanroom environments, but suffer the inadequacies of high costs of ownership, performance shortfalls, and slow speeds of response.

Today, the Picarro SI2000 Series analyzers offer the power of highly sensitive laser spectroscopy techniques for AMC cleanroom monitoring in a reliable, easy-to-use, compact spectrometer design. Optimized for long-term stability and low maintenance, these analyzers do not require field calibration, employ unique materials of construction for the fastest response times in measuring the sticky inorganic gases of HF, NH3 and HCl, and are ideal for continuous operation in semiconductor-manufacturing facilities. Enclosed in a standard 19-inch rack mountable enclosure, and paired with a multi-port sequencer and datalogger, these analyzers are currently installed in major semiconductor users’ FAB locations monitoring cleanroom air to the lowest ppt concentrations possible in real time with adherence to the process industry standard: IEC 61207 for performance and several SEMI standards for verified MDL as well as calculations for reliability and safety.

The SI2000 series analyzers can be commissioned and operating within minutes without the need for zero sample preparation. The analyzers can operate for months without user interaction, and concentration trending data is continuously archived to the analyzer’s internal hard drive. The analyzer can be configured to automatically export measurement data at regular intervals via Ethernet, RS-232 interface, Analog 4-20 mA or Modbus outputs. Users can connect remotely with the analyzer’s Linux OS through a standard Remote Desktop connection or with similar remote login software. The analyzer can also use its Ethernet connection to automatically synchronize with an atomic-clock time service. Picarro strategically aligns with trained local integrators and service partners to ensure rapid support and regular preventative maintenance practices. While CRDS techniques do not have the need for field calibrations, Picarro recognizes the need for scheduled system validations in-order-to confirm trending data. Traditional validation methods employing the use of reactive gases can take up to 48 hours to set-up and complete. A new process has been developed for the SI2000 Series that requires less than 15 minutes to accomplish a system validation. The total estimated annual system downtime for both preventative maintenance and annual system validation is less than one hour. Furthermore, every SI2000 Series product will be accompanied by a detailed, serially controlled, document package showing the exact performance of each analyzer.