Control device for specific resistance of ultrapure water

Abstract

Abstract PURPOSE:To eliminate the generation of static electricity in a wafer by diverting a part of ultrapure water from a main flow passage, bringing the same into contact with carbon dioxide, joining such water with the main flow passage, measuring the specific resistance of the mixed ultrapure water and controlling the joining flow rate of the branched flow of the ultrapure water. CONSTITUTION:One end of a branch flow passage 2 is connected to the upper stream branch point 1a of a main flow passage 1 for ultrapure water connecting to a spray nozzle, etc. and is connected to the passage 1 at a down stream confluent point 1b. A contact column 3 with carbon dioxide having a packed material layer is provided in the mid-way of the passage 2, and a flow rate control valve 4 is provided on the down stream thereof. A part 1m<3>/H of the ultrapure water having 18MOMEGAcm specific resistance flowing in the passage 1 at 15m<3>/H flow rate to the branch point 1a is admitted into the passage 2, and 75mg/ml carbon dioxide is dissolved therein in the column 3. Said water is joined and mixed with the remaining 14m<3> ultrapure water and the specific resistance of the joined ultrapure water is made 10MOMEGAcm, then such water is supplied to the spray nozzle, etc.

Inventors

• 👤 Takashi Omori
• 👤 大森　孝志
• 👤 Katsunori Kuroki
• 👤 勝憲 黒木

Bibliographic Details