Chemical/mechanical polishing method for electronic part substrate

PURPOSE: To provide an allowable flat substrate surface by contacting a substrate which has etching speed different from that of specified etching liquid with a polishing pad and contacting that substrate with a slurry containing the etching liquid composed of abradant particles, chelate salt of transient metal and its solvent. CONSTITUTION: Concerning an electronic part substrate having two characteristics such as a ceramic substrate having metal bias, for example, having the etching speed different from that of specified etching liquid, this substrate is contacted with the polishing pad, contacted with the slurry containing the specified etching liquid, and planarized by chemical/mechanical polishing. This slurry is composed of the abradant particles, chelate salt of transient metal and solvent for this salt, the chelate salt of transient metal exerts chemical operation or etching operation upon the solvent, and the abradant particles exert mechanical operation in cooperation with the polishing pad. Thus, the substrate surface can be almost planarized.