| 摘要 |
<p>PURPOSE:To make heat transmission conditions fixed by changing a contact pressure between a wafer and a fixing base in accordance with a pressure difference between an atmospheric pressure of an inside of a bellows and that of an outside thereof. CONSTITUTION:A movable board 4 and a clamp ring 2 are connected to both ends of a rod 3 which passes through a fixing base 1 which is provided with a temperature controlling medium flow path 1a. A bellows 5 is interposed between the base 1 and board 4, and the ring 2 brings a wafer 6 into contact with the fixing base 1 by pressure difference between an atmospheric pressure of an inside of the bellows 5 and that of a periphery thereof. When an atmospheric pressure outside the bellows 5 lowers and vacuum degree increases, a contact pressure between the wafer 6 and the base 1 increases, thereby reducing the contact pressure in accordance with lowering of vacuum degree. Therefore, the higher vacuum degree is, the more effectively it compensates for lowering of heat transmission between the wafer 6 and the base 1. It is therefore possible to correct change of heat transmission in accordance with vacuum degree if conditions are adjusted.</p> |
