Double-beam light source apparatus, position detecting apparatus and aligning apparatus

Claim 2

A double-beam light source apparatus comprising: a light source system for supplying a beam; and a frequency difference producing system disposed in an optical path of the beam outgoing from said light source system to split it into two beams, that produces a predetermined frequency difference between said two beams to output said two beams radially spreading, the frequency difference producing system comprising: a beam splitting unit for splitting the beam outgoing from said light source system incident thereinto into two beams radially spreading from a first predetermined position to output the two split beams; a relay optical system for receiving the two beams outgoing from said beam splitting unit and converging the two beams at a second predetermined position; and a modulating unit disposed at said second predetermined position, for modulating a frequency of the converging two beams incident to said modulating unit in accordance with an incident direction thereof and for changing an outgoing direction thereof, wherein transmission optical path lengths of the two beams are identical to each other and the two beams having said predetermined frequency difference are made separately outgoing.

Claim 3

A double-beam light source apparatus according to claim 1, wherein said light source system comprises a light source emitting a beam of single wavelength and a condensing optical unit for condensing the beam from said light source.

Claim 4

A double-beam light source apparatus according to claim 1, wherein said light source system comprises a light source for generating a beam including light of plural wavelengths and a condensing optical unit for condensing the beam from said light source.

Claim 5

A double-beam light source apparatus according to claim 1, wherein said beam splitting unit comprises a diffraction grating.

Claim 6

A double-beam light source apparatus according to claim 1, wherein said relay optical system comprises a lens group having a positive refractive power and a conjugate point of said lens group is at said second predetermined position.

Claim 7

A double-beam light source apparatus according to claim 1, wherein said modulating unit comprises an acousto-optic modulator, which effects Bragg diffraction on incident light by a diffraction grating pattern formed by a compressional wave applied to said acousto-optic modulator.

Claim 8

A double-beam light source apparatus according to claim 6, wherein said compressional wave applied to said acousto-optic modulator travels in a direction approximately normal to a direction of a sum vector obtained from wave vectors of the two beams incident into said acousto-optic modulator.

Claim 9

A double-beam light source apparatus according to claim 6, wherein a traveling direction of the compressional wave applied to said acousto-optic modulator crosses a plane including the wave vectors of two beams incident into said acousto-optic modulator.

Claim 10

A double-beam light source apparatus according to claim 1, further comprising optical unit for collimating said two radially spreading beams outgoing from said frequency difference producing system.

Claim 11

A position detecting apparatus comprising: 1) a double-beam light source apparatus comprising: a light source system for supplying a beam; and a frequency difference producing system disposed in an optical path of the beam outgoing from said light source system to split it into two beams, that produces a predetermined frequency difference between said two beams to output said two beams radially spreading, in which transmission light path lengths of the two beams are identical to each other and the two beams having said predetermined frequency difference are made separately outgoing, the frequency difference producing system comprising: (i) a beam splitting unit for splitting the beam outgoing from said light source system incident thereinto into two beams crossing at a first predetermined position and radially spreading to output the two split beams; (ii) a relay optical system for receiving the two beams outgoing from said beam splitting unit and converging the two beams at a second predetermined position; and (iii) a modulating unit disposed at said second predetermined position, for modulating a frequency of the converging two beams incident to said modulating unit in accordance with an incident direction thereof and for changing an outgoing direction thereof; 2) a light separating unit for separating the two beams outgoing from said double-beam light source apparatus into two sets of double beams; 3) a first condensing system for receiving a set of double beams outgoing from said light separating unit and condensing the set of double beams at a reference diffraction grating; 4) a first photodetector for detecting an optical information resulting from diffraction by said reference diffraction grating; 5) a second condensing system for condensing the other set of double beams outgoing from said light separating unit, the second condensing system condensing the other set of double beams on a diffraction grating formed on an object to be measured; 6) a second photodetector for detecting an optical information resulting from diffraction by the diffraction grating; and 7) an optical information processing system for receiving an output signal of said first photodetector and an output signal of said second photodetector to compare the both optical information with each other and for calculating a displacement amount of said object to be measured from a reference position.

Claim 12

A position detecting apparatus comprising: 1) a double-beam light source apparatus comprising: a light source system for supplying a beam; and a frequency difference producing system disposed in an optical path of the beam outgoing from said light source system to split it into two beams, that produces a predetermined frequency difference between said two beams to output said two beams radially spreading, in which transmission light path lengths of the two beams are identical to each other and the two beams having said predetermined frequency difference are made separately outgoing, the frequency difference producing system comprising: (i) a beam splitting unit for splitting the beam outgoing from said light source system incident thereinto into two beams crossing at a first predetermined position and radially spreading to output the two split beams; (ii) a relay optical system for receiving the two beams outgoing from said beam splitting unit and converging the two beams at a second predetermined position; and (iii) a modulating unit disposed at said second predetermined position, for modulating a frequency of the converging two beams incident to said modulating unit in accordance with an incident direction thereof and for changing an outgoing direction thereof; 2) a light separating unit for separating the two beams outgoing from said double-beam light source apparatus into two sets of double beams; 3) a first condensing system for receiving a set of double beams outgoing from said light separating unit and condensing the set of double beams at a reference diffraction grating; 4) a first photodetector for detecting an optical information resulting from diffraction by said reference diffraction grating; 5) a second condensing system for condensing the other set of double beams outgoing from said light separating unit, the second condensing system condensing the other set of double beams on a diffraction grating formed on an object to be measured; 6) a second photodetector for detecting an optical information resulting from diffraction by the diffraction grating; and 7) an optical information processing system for receiving an output signal of said first photodetector and an output signal of said second photodetector to compare the both optical information with each other and for calculating a displacement amount of said object to be measured from a reference position.

Claim 13

A position detecting apparatus according to claim 10, wherein said light source system comprises a light source emitting a beam of single wavelength and a condensing optical unit for condensing the beam from said light source.

Claim 14

A position detecting apparatus according to claim 10, wherein said light source system comprises a light source emitting a beam including light of plural wavelengths and a condensing optical unit for condensing the beam from said light source.

Claim 15

A position detecting apparatus according to claim 10, wherein said beam splitting unit comprises a diffraction grating.

Claim 16

A position detecting apparatus according to claim 10, wherein said relay optical system comprises a lens group having a positive refractive power and a conjugate point of said lens group is at said second predetermined position.

Claim 17

A position detecting apparatus according to claim 10, wherein said modulating unit comprises a first acousto-optic modulator, which effects Bragg diffraction on incident light by a diffraction grating pattern formed by a compressional wave applied to said acousto-optic modulator.

Claim 18

A position detecting apparatus according to claim 15, wherein said compressional wave applied to said acousto-optic modulator travels in a direction approximately normal to a direction of a sum vector obtained from wave vectors of the two beams incident into said acousto-optic modulator.

Claim 19

A position detecting apparatus according to claim 15, wherein a traveling direction of the compressional wave applied to said acousto-optic modulator crosses a plane including the wave vectors of two beams incident into said acousto-optic modulator.

Claim 20

A position detecting apparatus according to claim 10, further comprising: a third condensing system for re-condensing two diverging beams after condensed by said second condensing system; and a third photodetector for detecting an optical information resulting from diffraction by a diffraction grating formed on a second object to be measured, and disposed at a condensing position of said third condensing system; wherein said optical information processing system receives an output signal of said third photodetector in addition to the output signals of said first and second photodetectors to obtain a relative positional deviation between a position of said first object to be measured and a position of said second object to be measured.

Claim 21

An aligning apparatus comprising: a position detecting apparatus as set forth in claims 18, a first drive unit for said first object to be measured; and a second drive unit for said second object to be measured; wherein said aligning apparatus performs alignment by adjusting the positional deviation between the objects to be measured.

Claim 22

An exposure apparatus comprising: 1) an illumination optical system for illuminating an exposure light on a mask to replicate a predetermined pattern formed on said mask onto a substrate; 2) a position detecting system for optically detecting positions of said mask and said substrate, respectively; 3) a calculating unit for calculating relative displacement between said mask and said substrate based on an output from said position detecting system; and 4) a driving unit for relatively moving said mask and said substrate based on an output from said calculating unit, said position detecting system comprising: a double-beam light source apparatus comprising: a light source system for supplying a beam; and a frequency difference producing system disposed in an optical bath of the beam outgoing from said light source system to split it into two beams, that produces a predetermined frequency difference between said two beams to output said two beams radially spreading, in which transmission light path lengths of the two beams are identical to each other and the two beams having said predetermined frequency difference are made separately outgoing, the frequency difference producing system comprising: (i) a beam splitting unit for splitting the beam outgoing from said light source system incident thereinto into two beams crossing at a first predetermined position and radially spreading to output the two split beams; (ii) a relay optical system for receiving the two beams outgoing from said beam splitting unit and converging the two beams at a second predetermined position; and (iii) a modulating unit disposed at said second predetermined position, for modulating a frequency of the converging two beams incident to said modulating unit in accordance with an incident direction thereof and for changing an outgoing direction thereof; (b) a first optical condensing system for respectively condensing the two beams output from said double-beam light source apparatus on diffraction grating marks respectively formed on said mask and said substrate; (c) a first photodetector for detecting a light grated by said diffraction grating formed on said substrate to output a first detection signal to said calculating unit; and (d) a second photodetector for detecting a light grated by said diffraction grating formed on said mask to output a second detection signal to said calculating unit.

Claim 23

An exposure apparatus comprising: 1) an illumination optical system for illuminating an exposure light on a mask to replicate a predetermined pattern formed on said mask onto a substrate; 2) a position detecting system for optically detecting positions of said mask and said substrate, respectively; 3) a calculating unit for calculating relative displacement between said mask and said substrate based on an output from said position detecting system; and 4) a driving unit for relatively moving said mask and said substrate based on an output from said calculating unit, said position detecting system comprising: a double-beam light source apparatus comprising: a light source system for supplying a beam; and a frequency difference producing system disposed in an optical bath of the beam outgoing from said light source system to split it into two beams, that produces a predetermined frequency difference between said two beams to output said two beams radially spreading, in which transmission light path lengths of the two beams are identical to each other and the two beams having said predetermined frequency difference are made separately outgoing, the frequency difference producing system comprising: (i) a beam splitting unit for splitting the beam outgoing from said light source system incident thereinto into two beams crossing at a first predetermined position and radially spreading to output the two split beams; (ii) a relay optical system for receiving the two beams outgoing from said beam splitting unit and converging the two beams at a second predetermined position; and (iii) a modulating unit disposed at said second predetermined position, for modulating a frequency of the converging two beams incident to said modulating unit in accordance with an incident direction thereof and for changing an outgoing direction thereof; (b) a first optical condensing system for respectively condensing the two beams output from said double-beam light source apparatus on diffraction grating marks respectively formed on said mask and said substrate; (c) a first photodetector for detecting a light grated by said diffraction grating formed on said substrate to output a first detection signal to said calculating unit; and (d) a second photodetector for detecting a light grated by said diffraction grating formed on said mask to output a second detection signal to said calculating unit.

Claim 24

An exposure apparatus according to claim 20, further comprising a projection optical system for projecting said predetermined pattern on said mask on said substrate with a predetermined magnification.

Claim 25

An exposure apparatus according to claim 20, further comprising: a beam splitting unit for splitting the two beams output from said double-beam light apparatus into two light beam sets; a second optical condensing system for receiving two beams in one of the two light beam sets which are split by said beam splitting unit, and condensing said two beams at a standard detraction grating; and a third photo-detector for detecting a light grated in said standard detraction grating to output a third detection signal to said calculating unit, said calculating unit calculating a relative displacement between said mask and said substrate.

Claim 26

An exposure apparatus according to claim 20, wherein said driving means comprises: mask holding units for holding said mask and a substrate holding unit for holding said substrate, either one of said mask holding units and said substrate holding unit being moved based on an output from said calculating unit.

Claim 27

An exposure apparatus according to claim 20, wherein said light source system comprises a light source emitting a beam of single wavelength and a condensing optical unit for condensing the beam from said light source.

Claim 28

An exposure apparatus according to claim 20, wherein said light source system comprises a light source emitting a beam including light of plural wavelengths and a condensing optical unit for condensing the beam from said light source.

Claim 29

An exposure apparatus according to claim 20, wherein said beam splitting unit comprises a diffraction grating.

Claim 30

An exposure apparatus according to claim 20, wherein said relay optical system comprises a lens group having a positive refractive power and a conjugate point of said lens group is at said second predetermined position.

Claim 31

An exposure apparatus according to claim 20, wherein said modulating unit comprises an acousto-optic modulator, which effects Bragg diffraction on incident light by a diffraction grating pattern formed by a compressional wave applied to said acousto-optic modulator.

Claim 32

An exposure apparatus according to claim 28, wherein said compressional wave applied to said acousto-optic modulator travels in a direction approximately normal to a direction of a sum vector obtained from wave vectors of the two beams incident into said acousto-optic modulator.

Claim 33

An exposure apparatus according to claim 28, wherein a traveling direction of the compressional wave applied to said acousto-optic modulator crosses a plane including the wave vectors of two beams incident into said acousto-optic modulator.