Abstract: A particle counter may include a housing having an inlet, an outlet, and a window therebetween. The inlet and the outlet may be configured such that a fluid can be flowed therethrough. A plurality of light sources may be arranged outside the housing to provide lights of different wavelengths into the housing through the window. Sensors may be provided outside the housing to detect fractions of the lights scattered by a bubble and/or a particle in the fluid. A control part may be configured to monitor intensities of the lights detected by the sensors and to analyze a difference in intensity between the scattered lights, thereby distinguishing the particles from the bubbles in the fluid.

Abstract: A particle counter may include a housing having an inlet, an outlet, and a window therebetween. The inlet and the outlet may be configured such that a fluid can be flowed therethrough. A plurality of light sources may be arranged outside the housing to provide lights of different wavelengths into the housing through the window. Sensors may be provided outside the housing to detect fractions of the lights scattered by a bubble and/or a particle in the fluid. A control part may be configured to monitor intensities of the lights detected by the sensors and to analyze a difference in intensity between the scattered lights, thereby distinguishing the particles from the bubbles in the fluid.

Abstract: A photomask cleaning apparatus includes a photomask receiving stage and a laser supply unit. The photomask receiving stage is configured to receive and retain a photomask in a desired orientation. The photomask has a front face having a pellicle adhesive residue region thereon. The desired orientation is with the front face positioned to allow gravity to move particles on the front face away from the front face without interference from the front face of the photomask. The laser supply unit is configured to generate a laser beam that irradiates a target region on the front face of the photomask to remove a pellicle adhesive residue from the target region. The photomask cleaning apparatus is configured to move the target region on the front face of the photomask to irradiate the entire pellicle adhesive residue region. Methods of using the photomask cleaning apparatus are also provided.

Abstract: A photomask cleaning apparatus includes a photomask receiving stage and a laser supply unit. The photomask receiving stage is configured to receive and retain a photomask in a desired orientation. The photomask has a front face having a pellicle adhesive residue region thereon. The desired orientation is with the front face positioned to allow gravity to move particles on the front face away from the front face without interference from the front face of the photomask. The laser supply unit is configured to generate a laser beam that irradiates a target region on the front face of the photomask to remove a pellicle adhesive residue from the target region. The photomask cleaning apparatus is configured to move the target region on the front face of the photomask to irradiate the entire pellicle adhesive residue region. Methods of using the photomask cleaning apparatus are also provided.