Resistance Temperature Detectors (RTDs) manufacturing

By Rogelio Bautista | July 22, 2020 |

Manufacturing process of the Resistance Temperature Detector

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For temperature meassurement there are a lot of different methods that according to its operation principle can be clasified in touching and non-touching. Inside the clasification of contact thermometers, are found the thermocouples, thermistors and resistance temperature detectors.

A “Resistace Temperature Detector” (RTD) produces a variation in the material resistance from which it is made of when a change in temperature happens. When a metal is heated, it produces vibrations in its crystal structure, which reduces the electron mid speed, that is translated into an increase in electric resistance. This mentioned physical phenomena, allows to adjust the size and sensitivity of the detector.

The versatility of the RTDs allows its micro-manufacturing starting from metallic thin flms. The micro RTDs produce a minimal impact or neglegible in any component due its size and mass. The manufacturing of RTD can be achieved in rigid or flexible substrates with which is obtained an adaptable sensor in different geometries. the RTD is commonly fabricated from metals such as Nickel (Ni), Cupper (Cu) and Platinum (Pt), where platinum is the most widely used one because it shows a linear behaviour between the temperature increase and the electric resistance of this material. The dependent behaviour of the electric resistance against temperature follow a quadratic function behaviour.

In CIDESI we have the capability and methodology of RTD sensors manufacturing on rigid or flexible substrates such as Silicon (Si). The manufacturing process starts from the growth of a silicon oxide dielectric film, subsequently the metalization of the wafer is performed and through photolithography and recording processes the patterns of the designed sensor are obtained.