Surface‐modified RuO2‐based thick film resistors using Nd:YAG laser

An RuO2‐based thick film resistor (TFR) is a cermet‐type resistor which consists of RuO2 particles and glass. Paste containing organic vehicles is printed onto an insulating substrate, and subsequent firing at about 900 °C makes the cermet‐type resistors. TFRs are widely utilized as electrical resistive materials in electric devices such as hybrid ICs (integrated circuits) [see, for example, R. W. Vest, Ceram. Bull. 65, 631 (1986)]. The features of an advanced laser application process to control the electrical resistivity of the TFRs were proposed. This new process is an application of surface‐modification using laser beams. In this paper, a mechanism of the surface‐modification of the TFR is considered using results of morphology observation, x‐ray diffraction (XRD), and x‐ray photoemission spectroscopy (XPS). The following points should be noticed. (1) In the surface‐modifying process using normal mode pulse Nd:YAG laser beams, glass in the TFR is modified and supersaturated with ruthenium impurities b...