Patent ID: 9631963
Date: 2017-04-25
CPC Classifications: B05C,G01F

Claim:
1. An apparatus configured to perform a solution process by supplying a processing solution from a processing solution supply source to the substrate held on a substrate holder via a flow path member and a nozzle, the apparatus comprising: a solution transfer unit configured to transfer the processing solution to the nozzle, and mounted to the flow path member; an ultrasonic flowmeter mounted to the flow path member at a downstream side from the solution transfer unit; a bubble detection unit configured to detect a bubble in the processing solution based on a variation of flow rates measured by the ultrasonic flowmeter, and connected to the ultrasonic flowmeter; a valve mounted to the flow path member at a downstream side from the ultrasonic flowmeter for discharging the bubble; and a control unit configured to control the bubble to be discharged by closing the valve if a number of times when the ultrasonic flowmeter detects the bubble exceeds a threshold, wherein a lower limit of a flow rate range which is measured by the ultrasonic flowmeter is equal to or less than 1 mL/sec, and wherein the ultrasonic flowmeter includes: a first piezoelectric element and a second piezoelectric element, which are spaced apart from each other in a flow direction of the processing solution, and are formed in a circular shape to surround a periphery of the flow path member; and a measuring unit configured to measure the flow rate of the processing solution, based on a variation of ultrasonic propagation times between when ultrasonic is propagated from the first piezoelectric element to the second piezoelectric element and when the ultrasonic is propagated from the second piezoelectric element to the first piezoelectric element.