Parts Per Million Detection in Semiconductor Facilities

Containers of hazardous gases, both flammable and toxic, are often isolated from the surrounding environment by safety enclosures (gas cabinets). Some process tools have a gas control enclosure section that serves the same purpose as a gas cabinet. It is important to monitor these enclosures for leaking gas to save product as well as prevent a toxic condition. The cabinets and enclosures are ventilated to prevent the buildup of any leaking gas.

Detecting the diluted leak requires a gas sensor in the low ppm range. Placement of parts per million sensors in the exhaust duct will allow continuous sampling of all air moving through the enclosure. When a leak is detected, the detection system can sound an alarm to notify personnel, and /or close a delivery valve to stop the flow of gas from the cylinder.

• Some process tools have gas enclosures that contain the piping jungle carrying hydrogen and toxic gases. These gases are introduced into processes in metered quantities to obtain product specifications. Any type of leak could jeopardize the integrity of the lot resulting in loss of product. In addition, many of these gases are highly toxic and require precautions to protect personnel.Continuous monitoring and early warning are the best means of preventing these types of accidents.
• A clean room is an enclosed contamination-free environment where state-of-the-art manufacturing and assembly take place. Clean rooms range from very small chambers to large scale rooms. Piping carrying process gases are connected to deposition, etching and other process tools. The connections are sources of possible leaks and contamination. Therefore, the air must be continuously monitored for ppm levels of hazardous leaking gas.

Control Instruments parts per million sensors employ electrochemical sensing technology. The sensors are rugged, highly stable and excellent for detecting low parts-per-million concentrations of selected gases in gas cabinets, enclosures and clean rooms. They offer immunity to cross interference, low maintenance, excellent repeatability and long-term stability.