Exposure apparatus and device manufacturing method

1. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

an exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas,

wherein said exhaust port is provided along the entire periphery at a lower end of said cover.

2. An apparatus according to claim 1 , further comprising another exhaust port provided in said cover while being opposed to said first supply port, for exhausting a gas from the space surrounded by said cover, wherein an exhaust flow rate of gas exhausted through said other exhaust port is made smaller than an amount of supply of purge gas supplied through said first supply port, and wherein an exhaust flow rate of gas exhausted through said first and second exhaust ports is made larger than the amount of supply of purge gas supplied through said first supply port.

3. An apparatus according to claim 1 , further comprising another exhaust port provided in said cover while being opposed to said first supply port, for exhausting a gas from the space surrounded by said cover, and another supply port provided outside said supply port and inside said exhaust port, in the stage-side end portion of said cover, for supplying a purge gas therethrough, wherein an exhaust flow rate of gas exhausted through said other exhaust port is made smaller than an amount of supply of purge gas supplied through said supply ports, and wherein an exhaust flow rate of gas exhausted through said first and second exhaust ports is made larger than the amount of supply of pure gas supplied through said supply ports.

4. A device manufacturing method, comprising the steps of:

transferring a pattern of an original onto a substrate by use of an exposure apparatus as recited in claim 1 ; and

developing the substrate having the pattern transferred thereto.

5. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

an exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas,

wherein an exhaust flow rate of gas exhausted through said exhaust port is made larger than an amount of supply of purge gas supplied through said supply port.

6. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

a first exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas;

a second exhaust port provided in an end portion of said cover at a side facing said stage and at a position outside said first exhaust port, for exhausting the gas,

wherein an exhaust flow rate of gas exhausted through said first exhaust port is made smaller than an amount of supply of purge gas supplied through said supply port, and wherein an exhaust flow rate of gas exhausted through said first and second exhaust ports is made larger than the amount of supply of purge gas supplied through said supply port.

7. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

a first exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas;

a second exhaust port provided in an end portion of said cover at a side facing said stage and at a position outside said first exhaust port, for exhausting the gas; and

a mirror provided on said stage and a laser interferometer for measuring a position of said mirror,

wherein said first exhaust port is provided in a portion of said cover opposed to said mirror and at the stage side end thereof.

8. An apparatus according to claim 7 , further comprising an air conditioning unit for blowing a gas toward a light path of said laser interferometer.

9. An apparatus according to claim 8 , wherein a gas from said air conditioning unit has an impurity concentration higher than that of the purge gas.

10. An apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a first supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

a first exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas;

a second exhaust port provided in said cover while being opposed to said first supply port, for exhausting a gas from the space surrounded by said cover; and

a second supply port provided outside said first supply port and inside said first exhaust port, in the stage-side end portion of said cover, for supplying a purge gas therethrough.

11. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover; and

an exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas;

a control system having a pressure sensor for detecting a pressure of any one of the space surrounded by said cover, a space outside said cover, and a space between the stage-side end portion of said cover and said stage,

wherein said control system controls at least one of the purge gas supply amount and the gas exhaust amount on the basis of the detection made through said pressure sensor.

12. An exposure apparatus comprising:

a projection optical system for projecting a pattern of an original onto a substrate;

a stage for holding the substrate;

a cover for substantially surrounding an exposure light path, from an end portion of said projection optical system, at a side facing said stage, to said stage;

a supply port provided inside said cover, for supplying a purge gas into a space surrounded by said cover;

an exhaust port provided in an end portion of said cover at a side facing said stage, for exhausting the gas; and

an exhaust system for exhausting a gas from said exhaust port,

wherein said exhaust system exhausts the gas from said exhaust port, via a reservoir.