DETECTION OF IMPURITIES IN THE SUB-PPB RANGE
The measurement of very small impurities in liquids is a major issue, especially in environmental analysis or process monitoring. In the semiconductor industry, for example, minute impurities in production can lead to a greatly increased error rate. The impurities should therefore be registered as soon as possible. However, methods for the in-situ measurement of impurities such as the optical measurement of scattered light in liquids are not very sensitive because they can register only larger impurities (in the range of several 100 nm and larger). Other methods which can also detect minute impurities dissolved in the liquid are generally based on complex methods such as atomic absorption spectroscopy or ion chromatography and can not be carried out in situ.
The present invention describes a sensor system which allows to analyze smallest impurities dissolved in the liquid down to the sub-ppb range. The measurement is based on an optical method, in which the impurities are detected in an extremely long optical path within the sensor. A particularly high sensitivity is the sensor for metallic impurities. The design of the sensor allows for a strong miniaturization so that it can be used, for example, can also be used in lab-on-a-chip devices, which are becoming increasingly prevalent in mobile analytics.
- Semiconductor industry
- Lab on chip
(1) EP 2486388