| 摘要 |
PURPOSE:To keep treating liquid clean and to treat a semiconductor element stably, by controlling the quantity of the filtering of the treating liquid based on the output of a fine particle measuring instrument. CONSTITUTION:An inner talk 1a is filled with oxide film etching liquid. A circulating pump 2a is always operated. The dust in the overflowed liquid from an outer tank 1b is removed through a filter 3a. The temperature of the liquid is adjusted with a temperature adjusting device 4a. The liquid is returned into the inner tank 1a. The liquid in the inner tank 3a is a sampled in real time at every preset time in a fine particle measuring instrument 7 for the liquid. The number of the particles is counted. When the treating liquid is contaminated and the couted value exceeds a specified value (x), a control part 6 is operated and a circulating pump 2b is operated. Circulation through the system of a filter 3b and a temperature adjusting device 4b is performed. When the counted value becomes less than a specified value (y) (<x), the circulation is stopped. The value (x) is the total value of the dust particles having the size of 0.1 mum or more. The value can be changed in the range of 100-2,000/100 ml. In this constitution, metallic contamination and the like are prevented, and a semiconductor element can be manufactured stably.
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