The Thin Film type, platinum RTD design is based on the CHIP (integrated circuit) technology.
Differently from the ceramic, the thin film sensor uses a platinum layer applied on a high purity ceramic substrate through the sputtering system.
Sputtering is a process whereby particles are ejected from a solid target material due to bombardment of the target by energetic particles, particularly, in the laboratory, gas ions. It only happens when the kinetic energy of the incoming particles is much higher than conventional thermal energies. This process can lead, during prolonged ion or plasma bombardment of a material, to significant erosion of materials. It is commonly utilized for thin-film deposition.
This platinum layer is then structured by means of a photolithography system and obtains the final shape of a meander. The final resistance value is obtained by means of a laser system.
The typical use range of the sensor elements of the Thin Film type varies between -70 ºC and +600 ºC.
Due to its small reduced size and, consequently, with little mass, the Thin Film sensors present a quick response to the temperature variations.