A transportation body 1 for a flexible optical disk 10 has flexibility, and includes a rotation stabilizing board 2 having a disk-shaped form, an optical disk alignment unit 4 installed in the central part of the rotation stabilizing board 2, and a spacer 3 installed on a surface of the rotation stabilizing board 2. The vent piece has an inner wall formed with a baffle projection to prevent invasion of a splashing water. The control device includes a bypass valve comprising a valve-closure body which is configured to be pneumatically actuatable, and a control pressure space. An enclosed cavity is formed between the target substrate surface and the subassembly, and a seal of the cavity protects critical components residing on the active surface of the semiconductor device.