A substrate fixture includes a monopolar chuck main body comprising an insulated plate and an electrode embedded in the insulated plate, a tray placed on the chuck main body, having an upper surface in which a plurality of concave parts for accommodating therein a plurality of substrates is formed, and formed of an insulator having a volume resistivity equal to or lower than a volume resistivity of the insulated plate, and an yttrium oxide layer formed on the upper surface of the tray.