Patent ID: 11948804
Assignee: TOKYO ELECTRON LIMITED
Field: Semiconductors (Electrical engineering)
Classification: CPC H  C | IPC C  H

Claim 0:
1. A substrate processing method, comprising:
preparing a phosphoric acid processing liquid by supplying a precipitation inhibitor configured to inhibit precipitation of silicon oxide by being combined with a silicon oxide film of a substrate into a phosphoric acid aqueous solution;
etching the substrate having the silicon oxide film and a silicon nitride film by immersing the substrate in a processing tub in which the phosphoric acid processing liquid is stored; and
increasing a concentration of the precipitation inhibitor in the phosphoric acid processing liquid by additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid in the processing tub when a number of substrates etched by the phosphoric acid processing liquid has reached a first threshold value or when a silicon concentration in the phosphoric acid processing liquid has reached a second threshold value,
wherein the first threshold value or the second threshold value is determined based on a number of the additional supplies of the precipitation inhibitor, and
wherein the etching of the substrate comprises, after the increasing of the concentration of the precipitation inhibitor, etching a new substrate by immersing the new substrate in the processing tub in which the phosphoric acid processing liquid with the increased concentration of the precipitation inhibitor is stored.