Patent ID: 8608864

Claim:
A substrate treating method for treating substrates with a treating liquid, for use with a substrate treating apparatus having: a treating tank for storing the treating liquid; a supply pipe for circulating the treating liquid to supply the treating liquid discharged from the treating tank back to the treating tank; a first branch pipe shunted from the supply pipe; a cooling device mounted on the first branch pipe for cooling the treating liquid flowing therethrough; a second branch pipe interconnecting positions of the supply pipe upstream and downstream of the cooling device; a separating device mounted on the second branch pipe for separating deionized water and a solvent in the treating liquid, and discharging the deionized water from the treating liquid; an injection pipe connected to the supply pipe for injecting deionized water in a position downstream of the separating device; a third branch pipe interconnecting positions of the supply pipe upstream and downstream of the separating device; a deionized water removing device mounted on the third branch pipe for adsorbing and removing the deionized water from the treating liquid; a water-soluble solvent injecting device for injecting a water-soluble solvent into the injection pipe; and a water-insoluble solvent injecting device for injecting a water-insoluble solvent into the injection pipe; said method comprising: a deionized water cleaning step for cleaning the substrates inside the cleaning tank with deionized water; a replacing step for injecting the water-soluble solvent from said water-soluble injecting device into said supply pipe and replacing the deionized water with the water-soluble solvent; a cooling step executed by switching a channel to said first branch pipe for said cooling device to cool the treating liquid; a separating and removing step executed by switching a channel to said second branch pipe for said separating device to remove the deionized water from the treating liquid; an adsorbing and removing step executed, after said separating and removing step, by switching the channel to said third branch pipe for removing the deionized water from the treating liquid; a replacement promoting step for injecting the water-insoluble solvent from said water-insoluble solvent injecting device into said supply pipe; a determining step for determining whether a deionized water concentration in the treating liquid has fallen to a predetermined value; and a finishing step, executed when the deionized water concentration in the treating liquid has fallen to the predetermined value, for injecting the water soluble solvent again into the treating liquid of reduced deionized water concentration, so as to further decrease the deionized water concentration in the treating liquid.