Patent ID: 7656507

Claim:
A protection unit used to transfer a mask having a patterned surface from a mask stocker to a mask stage by a transfer unit that holds the mask by suction, the mask having a front surface and a back surface, the patterned surface being the front surface of the mask and having a pattern to be exposed onto a plate, said protection unit comprising: a holding part for holding the mask, said holding part including a contact part for contacting the back surface of the mask, said holding part holding the mask via the contact part; and a cover part for protecting the mask, said cover part being connected to the holding part and protecting the front surface of the mask in a non-contact manner, such that a space can be formed between the front surface of the mask and the cover part, wherein said protection unit covers the mask while leaving uncovered at least a part of the back surface of the mask, the part of the back surface of the mask being held by the transfer unit by suction.