| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent growth of a native oxide layer on the surface of an electronic component such as a wafer, etc., without supplying excess inert gas by comparing elapsed time with a preset prescribed threshold, determine which of them is larger, and notifying that the elapsed time has exceeded the threshold. SOLUTION: After closing a container 1 sealed tightly, the atmosphere in the container 1 varies due to trace leak amount with the lapse of time, and concentrations of oxygen and water content rise. The time until a native oxide has a prescribed thickness causing troubles is examined previously under a condition, where concentrations of oxygen and water content are made constant, and the product of concentration and time at this time is regarded as an approximate value of an integral value. This is set for threshold of an integral value of concentration of oxygen and that of water content. A wafer 13 is kept preserved in the container 1 in a range which does not exceed the threshold. An integrating timer 33 is provided with, for example, a warning device 34 as a means for notifying that the integrated value has reached the threshold.</p> |
