Some newer RGAs employ an ion trap as a mass analyzer rather than a quadrupole. The theory of operation of these systems is quite complex and well beyond the scope of this introductory work.
A number of compact, accurate and simple to use RGA systems are commercially available. MKS's RGA product line offers a variety of levels of RGA utility, from simple partial pressure analyzers to complex mass spectrometers.
MKS's Microvision 2 "smart head" technology collects data on potentially damaging residual gases that negatively impact the process quality at millisecond speed. The electronics unit mounts directly onto the analyzer head, and connects to the system PC via Ethernet. It is designed as an application specific tool to monitor pumpdown, baseline, and leakback conditions in semiconductor and thin film processes. The Vision 2000-C™, Vision 2000-E™, and Vision 2000-P™ RGAs combine a closed ion source with an automated inlet to enable monitoring of the complete CVD, PVD or Etch process cycle, from base vacuum to process pressures of up to 700 Torr. These RGAs incorporate Microvision 2 "smart head" technology and are integrated with the Process Eye™ Professional control platform. Process Eye is designed for process monitoring applications where a flexible control platform is required to achieve automation and full integration with a process tool. Process Eye Professional uses recipes to define the way in which the RGA scans, displays and responds to the data acquired.
MKS produces the 300mm Resist-Torr RGA for the detection of photoresist residues on wafers during the high pressure (~8 Torr) wafer degas step just prior to insertion of the wafer into a 300 mm PVD chamber. The 300 mm Resist-Torr is a fully automated monitor with built-in calibration for the calculation of the PR index that measures the photoresist contamination level in the degas chamber. The Resist-Torr employs a fast response capillary sample inlet to ensure vacuum integrity in the QMS. When integrated with Process Eye and TOOLweb RGA sensor control software, the 300mm Resist-Torr system provides completely automated operation and highly reliable photoresist detection.
The HPQ3 and HPQ3S are designed as in situ process monitoring tools that can operate well beyond the normal 1 x 10-4 mbar total pressure restriction of most RGAs without the need for differential pumping of the sample inlet. The lack of requirement for differential pumping significantly simplifies the operation of these tools and reduces their footprint in the process environment, making them particularly suitable as in situ monitors in a wide range of CVD, PVD and Etch applications, from leak detection to process monitoring.
Two categories of Cirrus gas analyzers are available, the Cirrus 3 product line and the Cirrus 3-XD.
The Cirrus 3 benchtop system is a state-of-the-art QMS specifically designed for high sensitivity and long-term analyzer stability. It is capable of near real-time monitoring of a wide array of gases and gas mixtures with a dynamic sensitivity range that varies between parts per billion (ppb) and percentage levels. It can be configured to sample up to 16 gas streams, with special configurations available to sample corrosive gases or to produce high mass resolution spectra. As well, it can be supplied with an integrated optical sensor for continuous carbon monoxide (CO) sensing. The Cirrus 3 incorporates an Ethernet interface, allowing it to be controlled by either a local PC or through an organizational network. It is operated using the Process Eye Professional control platform which allows for fully automated operation and calibration and which incorporates and tracks data from other process sensors.
Cirrus 3-XD atmospheric pressure gas analyzers are designed for research and engineering applications requiring trace gas analyses that are beyond the limits of normal QMS systems. The addition of patented V-lens™ ion optics technology to the Cirrus QMS platform provides a unique analytical advantage for the Cirrus 3-XD that ensures gas-independent low baseline and stable, robust detection of gases at low ppb levels. This guarantees a high level of confidence in trace level analyses. The fast response capillary inlet design allows the system to capture 250 data points per second for near real-time analyses. The Cirrus 3-XD employs the Process Eye Professional control platform for fully automated operation and calibration. Available in either benchtop or rack-mounted configurations, the Cirrus 3-XD is ideal for in-line monitoring and analysis of trace contaminants in process gases, including solvent vapors, hydrocarbons, atmospheric and inorganic gas species (including corrosives), freons, and noble gases.