Method for changing concentration of treatment solution and treatment solution supply apparatus

Abstract

According to the present invention, in changing the concentration of a treatment solution supplied to a substrate, a volume of an existing treatment solution in a tank connected to a treatment solution supply section for supplying the treatment solution to the substrate is first measured. Based on this measured value, a minimum drain volume of the existing treatment solution to be drained out from the tank and a supply volume of either a treatment solution with a predetermined concentration or a diluting fluid to be supplied into the tank is calculated respectively in order to change the treatment solution in the tank to be in an intended volume and to have an intended concentration. Then, the calculated drain volume of the existing treatment solution is drained out from the tank. Meanwhile, the calculated supply volume of either the treatment solution with the predetermined concentration or the diluting fluid is supplied into the tank. According to the present invention, since the drain volume in changing the concentration of the treatment solution can be reduced, a wasteful consumption volume of the treatment solution is reduced accordingly so that cost reduction can be realized. Moreover, the time required for the concentration change can be shortened.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a division of and claims the benefit of priority from U.S. Ser. No. 10 / 134,509, filed Apr. 30, 2002, and is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-134103, filed May 1, 2001, the entire content of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method for changing concentration of a treatment solution and a treatment solution supply apparatus. [0004] 2. Description of the Related Art [0005] In a photolithography process in semiconductor device fabrication processes, solution treatments using treatment solutions such as a resist coating treatment of applying a resist solution to the surface of a wafer to form a resist film and a developing treatment of supplying a developing solution and a washing fluid to an exposed wafer to develop the wafer are carried out. [000...

AI Technical Summary

Benefits of technology

This approach reduces wasteful drainage, shortens the time required for concentration changes, minimizes solution consumption, and enhances throughput by allowing for precise concentration adjustments without interrupting wafer treatments.

Problems solved by technology

Moreover, when the developing solution with the new concentration is stored, only a small volume of the developing solution left in the tank prevents strict maintenance of the concentration of the developing solution since the new developing solution and the existing developing solution are mixed together.

Therefore, in changing the concentration of the developing solution, a troublesome work of once draining out the developing solution with the new concentration which is temporarily stored in the tank and storing a developing solution with the same concentration again has been carried out.

A large volume of the developing solution has to be drained out if the developing solution in the tank is thus completely drained out each time the concentration of the developing solution is changed and a large volume of the developing solution is consumed to cause cost increase.

Furthermore, when the tank is large, it requires a lot of time to completely drain out the developing solution stored in this tank and thereafter, to supply the developing solution into the tank again and during that time, a wafer treatment is interrupted, which also causes a problem that a throughput is lowered.

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