초록 ▼

A differential pumping seal apparatus includes a differential pumping seal for sealing a first space and a second space from each other in a non-contact manner, and a back up seal mechanism for sealing the first space and the second space from each other in a contact manner. The back up seal mechani

A differential pumping seal apparatus includes a differential pumping seal for sealing a first space and a second space from each other in a non-contact manner, and a back up seal mechanism for sealing the first space and the second space from each other in a contact manner. The back up seal mechanism is operated to seal the first space and the second space from each other only when the differential pumping seal is stopped or while operation of said differential pumping seal is stopped.

대표청구항 ▼

What is claimed is: 1. A differential pumping seal apparatus for use in a semiconductor fabrication apparatus, said apparatus comprising: a hydrostatic bearing comprising a working fluid supply source; a differential pumping seal for sealing a first space and a second space from each other in a non

What is claimed is: 1. A differential pumping seal apparatus for use in a semiconductor fabrication apparatus, said apparatus comprising: a hydrostatic bearing comprising a working fluid supply source; a differential pumping seal for sealing a first space and a second space from each other in a non-contact manner so as to prevent fluid communication between the first space and the second space, a pressure of the first space being lower than a pressure of the second space; wherein during operation of said differential pumping seal, said working fluid supply source is maintained at a pressure greater than the pressure of said differential pumping seal, and a back up seal mechanism for sealing said first space and said second space from each other in a contact manner; wherein said back up seal mechanism, said hydrostatic bearing and said differential pumping seal are arranged in this order in a direction from the second space to the first space, and said back up seal mechanism seals said first space and said second space from each other only when operation of said differential pumping seal is stopped or while operation of said differential pumping seal is stopped. 2. A differential pumping seal apparatus according to claim 1, wherein said back up seal mechanism comprises a seal member for sealing said first space and said second space from each other, and said seal member is kept in a non-contact state by the force of a fluid or an external force so as not to perform a sealing function thereof when said differential pumping seal is in operation, and said seal member is kept in a contact state by its own elasticity or an external force so as to perform the sealing function thereof when said differential pumping seal is not in operation. 3. A differential pumping seal apparatus for use in a semiconductor fabrication apparatus said apparatus comprising: a partition wall for dividing a first space and a second space from each other; a movable body provided so as to pass through said partition wall; a hydrostatic bearing comprising a working fluid supply source; a differential pumping seal for sealing said first space and said second space from each other in a non-contact manner so as to prevent fluid communication between the first space and the second space, a pressure of the first space being lower than a pressure of the second space; wherein during operation of said differential pumping seal, said working fluid supply source is maintained at a pressure greater than the pressure of said differential pumping seal, and a back up seal mechanism for closing a gap between said partition wall and said movable body in a contact manner so as to seal said first space and said second space from each other; wherein said back up seal mechanism, said hydrostatic bearing and said differential pumping seal are arranged in this order in a direction from the second space to the first space, and said back up seal mechanism seals said first space and said second space from each other only when operation of said differential pumping seal is stopped or while operation of said differential pumping seal is stopped. 4. A differential pumping seal apparatus according to claim 3, wherein said back up seal mechanism has a shutter mechanism for opening and closing the gap between said partition wall and said movable body, and said shutter mechanism is operated to seal said first space and said second space from each other only when operation of said differential pumping seal is stopped or while operation of said differential pumping seal is stopped. 5. A differential pumping seal apparatus according to claim 3, wherein said back up seal mechanism has a seal member provided on said partition wall or said movable body, and said seal member is brought into contact with said partition wall or said movable body by its own elasticity so as to perform a sealing function thereof when said differential pumping seal is not in operation, and said seal member is kept out of contact with said partition wall or said movable body by the force of a fluid so as not to perform the sealing function thereof when said differential pumping seal is in operation. 6. A differential pumping seal apparatus for use in a semiconductor fabrication apparatus, said apparatus comprising: a first member for defining at least one of a first space and a second space whose atmospheres are different from each other; a second member movable relatively to said first member; a hydrostatic bearing comprising a working fluid supply source; a differential pumping seal for sealing a gap between said first space and said second space in a non-contact manner so as to prevent fluid communication between the first space and the second space, a pressure of the first space being lower than a pressure of the second space; wherein during operation of said differential pumping seal, said working fluid supply source is maintained at a pressure greater than the pressure of said differential pumping seal, and a seal element for separating said first space and said second space from each other in a contact manner only when said differential pumping seal does not function; wherein said seal element, said hydrostatic bearing and said differential pumping seal are arranged in this order in a direction from the second space to the first space, and said seal element comprises a diaphragm seal member which is extensible and has an edge portion fixed to said first member, and said diaphragm seal member projects toward said second member by a fluid pressure so as to be brought into contact with said second member. 7. A differential pumping seal apparatus according to claim 6, wherein said gap is formed on both sides of said first space, and said differential pumping seal for sealing said gap is provided at a position where said second member passes through said first member. 8. A differential pumping seal apparatus according to claim 6, further comprising: the hydrostatic bearing performs the bearing function in said gap; said hydrostatic bearing and said differential pumping seal being adjacent to each other in said gap, said hydrostatic bearing being disposed at a position where said hydrostatic bearing is closer to said second space than said differential pumping seal, and said seal element being disposed between said hydrostatic bearing and said second space. 9. A differential pumping seal apparatus for use in a semiconductor fabrication apparatus, said apparatus comprising: a first member for defining at least one of a first space and a second space whose atmospheres are different from each other; a second member movable relatively to said first member; a hydrostatic bearing comprising a working fluid supply source; a differential pumping seal for sealing a gap between said first space and said second space in a non-contact manner so as to prevent fluid communication between the first space and the second space, a pressure of the first space being lower than a pressure of the second space, said gap being formed only on one side of said second member, one of said first and second spaces being defined by said first member and said second member; wherein during operation of said differential pumping seal, said working fluid supply source is maintained at a pressure greater than the pressure of said differential pumping seal, a seal element for separating said first space and said second space from each other in a contact manner only when said differential pumping seal does not function, said seal element comprising a fixed seal member which is fixed to said first member and is capable of being brought into contact with said second member; and a push device for pushing said second member toward said first member to bring said second member into contact with said fixed seal member only when said differential pumping seal does not function wherein said seal element, said hydrostatic bearing and said differential pumping seal are arranged in this order in a direction from the second space to the first space. 10. A differential pumping seal apparatus according to claim 9, further comprising: the hydrostatic bearing performs the bearing function in said gap; said hydrostatic bearing and said differential pumping seal being adjacent to each other in said gap, said hydrostatic bearing being disposed at a position where said hydrostatic bearing is closer to said second space than said differential pumping seal, and said seal element being disposed between said hydrostatic bearing and said second space.