| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve filtration of dust by supplying an inert gas into a wafer case to replace the internal air with the inert gas. SOLUTION: When a vacuum pump 31 is operated, small dust contained in internal air in a wafer case 10 is filtered by a first filter and is sucked in a suction nozzle 30A to the outside. The pressure inside the wafer case 10 becomes negative or the pressure inside the wafer case 10 is reduced to a specific value, and then a valve 33 of an N2 gas cylinder 32 is opened. The N2 gas passes through a supply nozzle 30B and is supplied into the case 10. Final dust and dirt in the N2 gas is filtered when passing through a second filter unit 15B, thus substituting air in the case with the N2 gas and hence drastically reducing facility costs and filling the N2 gas into the wafer case 10 only for reducing the amount of the N2 gas and for quickly and efficiently performing substitution.</p> |
