For this purpose, the so-called prober is used. [0004] As such a prober, for example, Japanese Patent gazette No. 2587289, JP Kokoku Hei 3-40947, JP Kokai Hei 11-31724 and the like disclose wafer probers having a chuck top made of a metal such as aluminum alloy or stainless steel. [0005] About such a wafer prober, for example, as shown in FIG. 12, a silicon wafer W is put on a wafer prober 101, an