Samsung Electronics Co., Ltd.

Kwangshin Lim

Jinho Kim

Kihyun Kim

Sooyeon Kim

Jiyoung Kim

JungDae Park

Jeong-In Yoon

Min Soo Suh

Hyang Bong Lee

Provided is a method for detecting impurities in ammonium hydroxide. The method for detecting impurities in ammonium hydroxide includes preparing a potassium permanganate solution, preparing ammonium hydroxide, and adding the potassium permanganate solution several times to the ammonium hydroxide so as to detect impurities in the ammonium hydroxide. Potassium permanganate contained in the potassium permanganate solution is added for each time in the range of 0.0001 mol to 0.01 mol per 1 g of ammonia contained in the ammonium hydroxide.

Method for detecting impurities in ammonium hydroxide

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.

Particle counter and immersion exposure system including the same

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Yongin-si, South Korea

Kwangshin Lim