| 摘要 |
PURPOSE:To make it possible to rapidly cool a semiconductor substrate without imparting any abrupt external force to an inspection bed, by using a pump having a slow start and slow down characteristics as the pump for circulating a refrigerant through the inspection bed. CONSTITUTION:A liquid refrigerant is fed as indicated by an arrow A into a single pipe 4 directly connected to an inspection bed 2. As a result, the refrigerant is circulated through the inspection bed 2 and is forced out through another single pipe 5. The feed of the liquid refrigerant is performed by a pump having a slow start and slow down characteristics. If a pump having a quick start and quick stop characteristics is used, a drastic pressure drop is caused between the single pipe 4 and single pipe 5 and the inspection bed 2 is distorted due to the pressure difference. The distortion is transferred to the semiconductor substrate to vary the electric characteristics of the substrate. These problems are obviated by the use of the pump having slow start and slow down characteristics. |
