problem
Of critical importance for semiconductor wafer fabrication is the careful and accurate deposition of multiple layers of chemical materials to form thousands, millions or even billions of transistors in some cases to form a wide variety of complex integrated circuits ICs.) In manufacturing these ICs, different chemical gases are accurately metered at each step, and the amount of gas used varies widely depending on the process, and in most cases the steps are height Automated. Interestingly, not yet automated is actually a very simple step, that is, 'keep ample gas supply'.
In ADI's Silicon Valley facility near San Jose, CA, there are more than 175 dedicated gas tanks for wafer fabrication that are closely monitored to ensure uninterrupted gas supply. Unintended interruption of gas supply can lead to value In order to avoid downtime, the technician manually recorded the pressure of each tank in the factory three times a day.This manual process is prone to human error, Maintenance costs are also high.
This manual data recording method was previously used because it is considered unbelievably expensive to use in a factory because of the perceived wiring of communication systems.Gas are everywhere in the factory and most of the gas tanks have no AC power outlet or Ethernet Net socket. The factory was built with concrete walls for safety and seismic reasons, making the cost of installing new wires prohibitive and the large-scale installation of power and telecommunications lines interrupting the manufacturing process also requires the factory Shutdown.
Use wireless mesh network to solve the problem
To solve the wiring problem without interrupting the manufacturing process, a 32-node SmartMesh IP ™ wireless mesh network was initially deployed to monitor the pressure of each tank in the enclosure (Figure 2). Each node consists of a pair of The AA L91 lithium battery is powered to provide approximately 8 years of operational life under normal operating conditions, meaning the network can be installed without the need for additional wiring and downtime, requiring only periodic, periodic maintenance to replace the battery. The factory is a concrete building with a metal architecture that is ubiquitous, but the network has proven to be highly reliable. As of this writing, the network has been running continuously for more than 83 days, sending over 26 million packets of readings, of which only 1 Packet loss, which means reliability> 99.99999% .This is 100 times the stringent 5 5 reliability of high availability communication networks and computer systems.This level of network reliability ensures long-term plant maintenance free, And the system can withstand unfavorable changes in the factory and RF environment.
In a tank cabinet, the tank pressure and the steady pressure are measured for each tank and the measured readings are sent to a central monitoring system via the SmartMesh wireless network. Each SmartMesh node is connected to a pair of tanks and passed The wireless mesh network sends readings to a web server covering the entire building, displaying real-time readings in the control room through the factory's site management software tools and automatically calculating operating rates and trend curves to predict regular gas tank changes (Figure 3 ) In addition, a low pressure threshold is set, and if the tank pressure reaches the high alarm threshold before the set change time, an alarm is sent to the factory technician.The alarm is displayed on the control room monitor and Sent to factory technicians and factory management software over the Internet in the form of 'all-day long week'.
With real-time gas consumption rates, technicians can accurately predict when gas cylinders need to be replaced, reducing the amount of excess gas that can be wasted due to premature tank changes The benefits go beyond improving day-to-day operational efficiencies by concentrating gas Using volume data, effortlessly providing data to plant management and trend analysis, further simplifying plant operations can be found by analyzing the relationship between readings and specific semiconductor manufacturing processes and geometries. Optimize capacity growth as demand grows.
Alex McCann, chief operating officer at Analog Devices, states: "The increased efficiency shows that there is a good reason to install the SmartMesh gas cylinder monitoring network, so we plan to extend this wireless grid system across the plant to get it in our operations higher efficiency. '
to sum up
For semiconductor wafer processing facilities, productivity and downtime can be reduced if operating time is optimized, operational efficiencies SmartMesh IP Wireless Mesh Networks can be installed without disrupting plant operations to retrofit plants already in production, Monitors gas tank usage Wireless nodes are placed free of existing space, work reliably in metal and concrete structures, and send real-time readings like plant management software, which can be used to quickly and accurately determine gas usage , To ensure timely replenishment of gas, reduce downtime and gas waste.These data can also be used for capacity planning.Dust Networks
ADI's Dust Networks® products, together with the chipset and pre-certified PCB module for wireless mesh networking software, form a wireless connection that enables> 99.999% data reliability and ultra-low power when embedded in customer's sensor and gateway products Consuming, enabling sensors to sit in a harsh Industrial Internet of Things (IoT) environment. Dust Networks products are field-proven with more than 50,000 customer networks deployed in 120 countries.