TOFWERK, Thun, Switzerland
Cleanrooms are facilities where the purest environmental conditions are required for industrial production or research. Cleanrooms design aims to maximize production rates and yields for sensitive materials (microelectronics) and processes (wafer fabrication) . To meet stringent requirements, fast and sensitive monitoring of airborne molecular contaminants (AMCs) is essential.
The need for a high degree of cleanliness in fabs has forced adoption for industry standards. The adopted ISO 14644-1 standards range from ISO 1 to ISO 9 compliance, according to the quantity and size of particles permitted per volume of air.
Experimental Set Up
A Semicon AMC Monitor was placed in two fab cleanrooms meeting ISO 6 and ISO 8 respectively. In each cleanroom, direct air samples were taken from two different points, making a total of four sampling points as shown in Figure 1.
Cleanroom AMC Monitoring Results
The rapid response time of the monitors allowed for immediate assessment of the air quality at each sampling point, accurately detecting process failures and the presence of undesirable contaminants.
Figure 2 shows measured concentrations of acetone, acetic acid and cyclopentanone from the four sampling points. The concentration of acetone was found to be constant at all sampling points, while cyclopentane concentration varied between cleanrooms. Higher concentrations were observed in Cleanroom 1, consistent with its ISO 8 class. Acetic acid concentration varies not only between rooms but between sampling points, suggesting differences in processes or ventilation.
The versatility and sensitivity of Semicon AMC Monitors allows for the simultaneous monitoring of different AMC categories. Figure 3 shows the spectrum captured in sampling point B with some molecules that exemplified the detection.
- Den et.al., Journal of The Electrochemical Society 153(2):G149-G159, 2005, DOI:10.1149/1.2147286