Exposure apparatus, exposure method, and device manufacturing method

An exposure method of exposing a substrate with illumination light via a projection optical system, the method comprising:

• moving a stage having a holder to hold the substrate, with a magnetic levitation type planar motor that drives the stage, on a base disposed below the projection optical system and an alignment system in an exposure station and a measurement station, in the exposure station an exposure operation of the substrate being performed via the projection optical system, the measurement station being different from the exposure station, and in the measurement station a detection operation of a mark of the substrate being performed by the alignment system, and the alignment system being provided at a metrology frame that supports the projection optical system;
• in the exposure station, measuring positional information of the stage in the exposure operation, with an encoder system having four heads provided at the stage, each of the four heads irradiating a first scale member from below with a measurement beam, the first scale member having four L-shaped sections in each of which a reflection-type grating is formed and a first opening substantially surrounded by the four sections, and the first scale member being provided at the metrology frame so that the projection optical system is located in the first opening and the first scale member is disposed on a lower end side of the projection optical system;
• in the measurement station, measuring positional information of the stage in the detection operation, with the encoder system having the four heads provided at the stage, each of the four heads irradiating a second scale member from below with the measurement beam, the second scale member having four L-shaped sections in each of which a reflection-type grating is formed and a second opening substantially surrounded by the four sections, and the second scale member being provided at the metrology frame so that the alignment system is located in the second opening and the second scale member is disposed on a lower end side of the alignment system;
• controlling movement of the stage based on measurement information of the encoder system;
• and
• switching one head of three heads used in the measurement to another head, of the four heads, during movement of the stage, wherein
• the four heads are provided at the stage so that a distance between two heads of the four heads is larger than each of a width of the first opening and a width of the second opening in a first direction, and a distance between two heads of the four heads is larger than each of a width of the first opening and a width of the second opening in a second direction, the first direction being in a predetermined plane orthogonal to an optical axis of the projection optical system, and the second direction being orthogonal to the first direction in the predetermined plane,
• a movement area of the stage in the exposure operation includes a first area, a second area, a third area, a fourth area and a fifth area,
• in the first area, three heads of the four heads except for a first head respectively facing three sections of the four sections of the first scale member except for a first section,
• in the second area, three heads of the four heads except for a second head different from the first head respectively facing three sections of the four sections except for a second section different from the first section,
• in the third area, three heads of the four heads except for a third head different from the first and the second heads respectively facing three sections of the four sections except for a third section different from the first and the second sections,
• in the fourth area, three heads of the four heads except for a fourth head different from the first, the second and the third heads respectively facing three sections of the four sections except for a fourth section different from the first, the second and the third sections, and
• in the fifth area, the four heads respectively facing the four sections,
• in the exposure operation, the stage is moved from one area of the first, the second, the third and the fourth areas to another area of the first, the second, the third and the fourth areas that is different from the one area, via the fifth area,
• the one head is switched to the another head when the stage is moved from the fifth area to the another area.

A making method of an exposure apparatus that exposes a substrate with illumination light via a projection optical system, the method comprising:

• providing a body having a metrology frame to support the projection optical system;
• providing an alignment system at the metrology frame in a measurement station, the alignment system detecting a mark of the substrate, and the measurement station being different from an exposure station in which exposure of the substrate is performed via the projection optical system;
• providing a base disposed below the projection optical system and the alignment system;
• providing a stage having a holder to hold the substrate, and disposed on the base;
• providing a drive system having a magnetic levitation type planar motor to drive the stage on the base;
• providing a first scale member having four L-shaped sections in each of which a reflection-type grating is formed and a first opening substantially surrounded by the four sections, the first scale member being provided at the metrology frame so that the projection optical system is located in the first opening and the first scale member is disposed on a lower end side of the projection optical system in the exposure station, and the stage being placed facing the first scale member in an exposure operation of the substrate;
• providing a second scale member having four L-shaped sections in each of which a reflection-type grating is formed and a second opening substantially surrounded by the four sections, the second scale member being provided at the metrology frame so that the alignment system is located in the second opening and the second scale member is disposed on a lower end side of the alignment system in the measurement station, and the stage being placed facing the second scale member in a detection operation of the mark by the alignment system;
• providing an encoder system that has four heads provided at the stage and measures positional information of the stage, each of the four heads irradiating the first scale member or the second scale member from below with a measurement beam;
• and
• providing a controller that controls the drive system based on measurement information of the encoder system, and switches one head of three heads used in the measurement to another head, of the four heads, during movement of the stage, wherein
• the four heads are provided at the stage so that a distance between two heads of the four heads is larger than each of a width of the first opening and a width of the second opening in a first direction, and a distance between two heads of the four heads is larger than each of a width of the first opening and a width of the second opening in a second direction, the first direction being in a predetermined plane orthogonal to an optical axis of the projection optical system, and the second direction being orthogonal to the first direction in the predetermined plane,
• a movement area of the stage in the exposure operation includes a first area, a second area, a third area, a fourth area and a fifth area,
• in the first area, three heads of the four heads except for a first head respectively facing three sections of the four sections of the first scale member except for a first section,
• in the second area, three heads of the four heads except for a second head different from the first head respectively facing three sections of the four sections except for a second section different from the first section,
• in the third area, three heads of the four heads except for a third head different from the first and the second heads respectively facing three sections of the four sections except for a third section different from the first and the second sections,
• in the fourth area, three heads of the four heads except for a fourth head different from the first, the second and the third heads respectively facing three sections of the four sections except for a fourth section different from the first, the second and the third sections, and
• in the fifth area, the four heads respectively facing the four sections,
• in the exposure operation, the stage is moved from one area of the first, the second, the third and the fourth areas to another area of the first, the second, the third and the fourth areas that is different from the one area, via the fifth area,
• the controller switches the one head to the another head when the stage is moved from the fifth area to the another area.