Stage apparatus and electron beam lithography system

A stage apparatus comprising:

• a surface plate;
• a guide shaft fixedly supported to the surface plate;
• a drive member that moves along the guide shaft such that a gap portion is left between the guide shaft and the drive member;
• a hydrostatic fluid bearing that forms fluid films in the gap portion, the fluid films having thickness dimensions;
• a positional deviation detection section for detecting a relative positional deviation which occurs between the guide shaft and the drive member and which affects the thickness dimensions of the fluid films;
• a state decision section for making a decision on a condition of the stage apparatus itself based on the positional deviation detected by the positional deviation detection section by comparing an amount of the positional deviation monitored by the positional deviation monitoring portion with at least one preset threshold value and outputting information responsive to the decision;
• and
• an information output portion,
• wherein the decision is at least one of a decision as to whether said amount of said positional deviation has reached a given threshold value for maintenance or a decision as to whether said amount of said positional deviation has reached a given threshold value for temperature control of the surface plate, and
• wherein the information output portion outputs information permitting identification of maintenance times as information regarding maintenance of the stage apparatus itself if the decision portion has determined that the amount of positional deviation has reached the threshold value for maintenance and the information output portion outputs information for giving an instruction to change the reference temperature as information for correction of the positional deviations if the decision portion has determined that the amount of positional deviation has reached the threshold value for temperature control of the surface plate.