Abstract: A cleaning method for cleaning an object involves disposing the object in a cleaning liquid held in a cleaning tank; and ultrasonically vibrating the cleaning liquid via an intermediate medium in contact with the cleaning tank, wherein the ultrasonically vibrating includes: ultrasonically vibrating the cleaning liquid with a first difference between respective sonic velocities allowable in the cleaning liquid and the intermediate medium; and ultrasonically vibrating the cleaning liquid with a second difference between the respective sonic velocities allowable in the cleaning liquid and the intermediate medium, wherein the second difference is different from the first difference.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a gas is dissolved includes preparing the liquid in which the gas is dissolved and stirring the liquid while irradiating the liquid with the ultrasonic waves so as to realize a state where bubbles containing the gas dissolved in the liquid continue to be generated. The object is cleaned in the state where the bubbles containing the gas continue to be generated.

Abstract: A cleaning method involves: disposing in a cleaning liquid held in a cleaning tank an object to be cleaned; and ultrasonically vibrating the cleaning liquid via an intermediate medium in contact with the cleaning tank to clean said object, the ultrasonically vibrating involving: ultrasonically vibrating the cleaning liquid with the cleaning liquid and the intermediate medium allowing sonic velocities, respectively, having a first difference; and ultrasonically vibrating the cleaning liquid with the cleaning liquid and the intermediate medium allowing sonic velocities, respectively, having a second difference different from the first difference.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a gas is dissolved includes preparing the liquid in which the gas is dissolved. The object is cleaned while applying ultrasonic waves to the liquid so that a ratio determined by dividing a vibration strength of the liquid at a fourth-order frequency of the ultrasonic waves by a vibration strength of the liquid at a fundamental frequency of the ultrasonic waves is larger than 0.8/1000.

Abstract: A cleaning method for cleaning an object involves disposing the object in a first cleaning liquid held in a first cleaning tank; ultrasonically vibrating the first cleaning liquid via a first intermediate medium in contact with the first cleaning tank; disposing the object in a second cleaning liquid held in a second cleaning tank; and ultrasonically vibrating the second cleaning liquid via a second intermediate medium in contact with the second cleaning tank, wherein the first cleaning liquid and the first intermediate medium allow sonic velocities, respectively, having a first difference from each other, wherein the second cleaning liquid and the second intermediate medium allow sonic velocities, respectively, having a second difference from each other, and wherein the first and second differences are different from each other.

Abstract: A cleaning method involves: disposing in a cleaning liquid held in a cleaning tank an object to be cleaned; and ultrasonically vibrating the cleaning liquid via an intermediate medium in contact with the cleaning tank to clean said object, the ultrasonically vibrating involving: ultrasonically vibrating the cleaning liquid with the cleaning liquid and the intermediate medium allowing sonic velocities, respectively, having a first difference; and ultrasonically vibrating the cleaning liquid with the cleaning liquid and the intermediate medium allowing sonic velocities, respectively, having a second difference different from the first difference

Abstract: A dissolved nitrogen concentration monitoring method is used for monitoring a dissolved nitrogen concentration of a cleaning liquid when an ultrasonic wave is irradiated onto the cleaning liquid in which a substrate is dipped. The method includes measuring an amount of increase of a dissolved oxygen concentration of the cleaning liquid resulting from an oxygen molecule generated from a water molecule as a result of a radical reaction caused by ultrasonic wave irradiation. A dissolved nitrogen concentration of the cleaning liquid is calculated from the measured amount of increase of dissolved oxygen concentration based on a predetermined relationship between a dissolved nitrogen concentration and an amount of increase of dissolved oxygen concentration.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a gas is dissolved includes preparing the liquid in which the gas is dissolved. The object is cleaned while applying ultrasonic waves to the liquid so that a ratio determined by dividing a vibration strength of the liquid at a fourth-order frequency of the ultrasonic waves by a vibration strength of the liquid at a fundamental frequency of the ultrasonic waves is larger than 0.8/1000.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a first gas is dissolved includes preparing the liquid in which the first gas is dissolved and introducing a second gas into the liquid while irradiating the liquid with ultrasonic waves so as to realize a state where bubbles containing the first gas dissolved in the liquid continue to be generated. The object is cleaned in the state where the bubbles containing the first gas continue to be generated.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a gas is dissolved includes preparing the liquid in which the gas is dissolved and stirring the liquid while irradiating the liquid with the ultrasonic waves so as to realize a state where bubbles containing the gas dissolved in the liquid continue to be generated. The object is cleaned in the state where the bubbles containing the gas continue to be generated.

Abstract: An ultrasonic cleaning method for cleaning an object in a liquid in which a gas is dissolved includes preparing the liquid in which the gas is dissolved and cleaning the object while irradiating the liquid with ultrasonic waves so that a region, where a spatial rate of change of a refractive index of the liquid in which the gas is dissolved is large relative to a case where ultrasonic waves are not applied, appears along a direction in which the ultrasonic waves travel.

Abstract: A calibration method for calibrating a measurement device for measuring a concentration of a gas dissolved in a liquid includes varying the concentration of the gas dissolved in the liquid, and predetermining, as a reference concentration, a concentration of the gas at which an intensity of luminescence produced when the liquid is irradiated with ultrasonic waves shows a peak. The liquid is illuminated with ultrasonic waves while varying the concentration of the gas in the liquid and a measured value is measured, using the measurement device, as a concentration of the gas in the liquid when the intensity of the luminescence shows a peak. The measurement device is calibrated based on the measured value and the reference concentration.

Abstract: A dissolved nitrogen concentration monitoring method is used for monitoring a dissolved nitrogen concentration of a cleaning liquid when an ultrasonic wave is irradiated onto the cleaning liquid in which a substrate is dipped. The method includes measuring an amount of increase of a dissolved oxygen concentration of the cleaning liquid resulting from an oxygen molecule generated from a water molecule as a result of a radical reaction caused by ultrasonic wave irradiation. A dissolved nitrogen concentration of the cleaning liquid is calculated from the measured amount of increase of dissolved oxygen concentration based on a predetermined relationship between a dissolved nitrogen concentration and an amount of increase of dissolved oxygen concentration.

Abstract: A cleaning method for cleaning an object includes preparing a cleaning liquid. A dissolved nitrogen concentration in the cleaning liquid is adjusted based on a size of a foreign substance to be removed from the object with a highest removal efficiency. The object is dipped in the cleaning liquid while irradiating the cleaning liquid with ultrasonic waves.

Abstract: A cleaning apparatus for cleaning an object includes a cleaning tank holding a cleaning liquid, the object being cleanable by the cleaning liquid. A coupling tank holding an intermediate medium is in contact with a portion of the cleaning tank. An ultrasonic wave generation unit is disposed at the coupling tank and configured to ultrasonically vibrate the cleaning liquid via the intermediate medium. A modification unit is configured to modify a difference in sonic velocity between the cleaning liquid and the intermediate medium.

Abstract: An ultrasonic cleaning method for cleaning an object in a solution having a gas dissolved therein includes irradiating ultrasonic waves to the solution having a first dissolved gas concentration. While the ultrasonic waves are being irradiated to the solution, a dissolved gas concentration in the solution is changed from the first dissolved gas concentration to a second dissolved gas concentration that is lower than the first dissolved gas concentration such that sonoluminescence occurs.

Abstract: A calibration method for calibrating a measurement device for measuring a concentration of a gas dissolved in a liquid includes varying the concentration of the gas dissolved in the liquid, and predetermining, as a reference concentration, a concentration of the gas at which an intensity of luminescence produced when the liquid is irradiated with ultrasonic waves shows a peak. The liquid is illuminated with ultrasonic waves while varying the concentration of the gas in the liquid and a measured value is measured, using the measurement device, as a concentration of the gas in the liquid when the intensity of the luminescence shows a peak. The measurement device is calibrated based on the measured value and the reference concentration.