Product Briefing Outline: The Swagelok CR-288 concentration monitor addresses a critical requirement in the semiconductor industry for improved monitoring and control of liquid chemicals employed in device manufacturing. Installed in the process stream or at point-of-use where chemicals are delivered or blended, the technology delivers real-time, highly accurate measurements of the concentration and temperature of process fluids. 

Problem: The CR-288 is claimed to be the first compact device in the industry to provide in-line analysis of liquid chemical concentration. Designed specifically for the semiconductor industry, it is physically small, easy to install, and serviceable in the field. Proprietary software enables a technician to calibrate the unit for chemical mixtures used in semiconductor laboratory or manufacturing processes, including etching, wafer cleaning, and chemical mechanical planarization (CMP). The software provides a graphical readout that the technician may customize for data logging over time.

Solution: Able to monitor up to four separate fluid streams with one digital display unit, the device can help the industry reduce chemical consumption, improve process control and visibility, detect process problems, reduce wafer scrap, and improve productivity. In addition, it will facilitate point-of-use spiking, blending, and mixing and help ensure chemical and ultrapure water quality. The CR-288 employs an LED light source, a mirror, a sapphire and a photodiode-array detector to measure refraction. Light is beamed at a sapphire window that is in contact with the process liquid. A reading is taken as the light bounces back, enabling computer software to determine the index of refraction for the liquid in question. That index of refraction may then be compared to the index of refraction for the desired blend or concentration of chemicals. The only components that come into contact with the liquid are the sapphire window and the body of the sensor, which is made of ultrahigh purity modified PTFE. A thermocouple inside the optical fluidic cell takes a temperature reading. A liquid’s index of refraction is a function of concentration and temperature.

Applications: Process stream or point of use.

Platform: Concentration accuracy: ± 0.1 %. Concentration accuracy is based on measuring ethylene glycol and water at 20 psig (1.3 bar), 76.1 to 78.8° F (24.5 to 26° C), and calibration range of 0 to 100%. Temperature accuracy: 0.1° C Temperature resolution: 0.01° C Response time: 1.2 s

Availability: October 2007 onwards.