Rotational deviation detecting method and system using a periodic pattern

Claim 2

A combination for detecting rotational deviation of an object, said combination comprising: a pattern provided on the object and having a periodicity; a laser for providing light; an optical system for projecting the light from said laser to said pattern; detecting means for detecting at least two diffraction lights, from said pattern, at a predetermined detection plane, wherein said optical system is disposed along a light path from said laser to said detecting means, and said optical system images a beam waist of said laser on a light path from said pattern to the predetermined detection plane; and determining means for determining rotational deviation of the object with respect to a predetermined axis, on the basis of incidence positions of the diffraction lights upon the predetermined detection plane, as detected by said detecting means.

Claim 3

A combination according to claim 1, wherein said pattern is provided by a diffraction grating.

Claim 4

A combination according to claim 1, wherein said pattern is provided by a circuit pattern.

Claim 5

A combination according to claim 1, wherein the two diffraction lights have diffraction orders of different signs.

Claim 6

A combination according to claims 4, wherein the two diffraction lights have diffraction orders of the same absolute value.

Claim 7

A combination according to claim 1, wherein said optical system projects the light from said laser to the pattern obliquely.

Claim 8

A combination according to claim 1, further comprising a rotationally movable holding base for holding the object, and control means for rotationally moving said holding base on the basis of the rotational deviation determined by said determining means.

Claim 9

A detection system for detecting positional deviation between first and second diffraction gratings provided on an object, said system comprising: a rotationally movable holding base for holding the object; a laser for providing light; an optical system for projecting the light from said laser to a pattern; first detecting means for detecting at least two diffraction lights, from the pattern, at a predetermined detection plane, wherein said optical system is disposed along a light path from said laser to said first detecting means, and said optical system images a beam waist of said laser on a light path from the pattern to said predetermined detection plane; determining means for determining rotational deviation of the object with respect to a predetermined axis, on the basis of incidence positions of the diffraction lights upon the predetermined detection plane, as detected by said first detecting means; second detecting means for detecting information related to the positional deviation between the first and second diffraction gratings; and control means for causing rotational motion of said holding base on the basis of the rotational deviation determined by said determining means and then causing said second detecting means to detect the information related to the positional deviation between the first and second diffraction gratings.

Claim 10

A detection system for detecting positional deviation between first and second diffraction gratings provided on an object, said system comprising: a rotationally movable holding base for holding the object; a laser for providing light; an optical system for projecting the light from said laser to a pattern; first detecting means for detecting at least two diffraction lights, from the pattern, at a predetermined detection plane, wherein said optical system is disposed along a light path from said laser to said first detecting means, and said optical system images a beam waist of said laser on a light path from the pattern to said predetermined detection plane; determining means for determining rotational deviation of the object with respect to a predetermined axis, on the basis of incidence positions of the diffraction lights upon the predetermined detection plane, as detected by said first detecting means; second detecting means for detecting information related to the positional deviation between the first and second diffraction gratings; and control means for causing rotational motion of said holding base on the basis of the rotational deviation determined by said determining means and then causing said second detecting means to detect the information related to the positional deviation between the first and second diffraction gratings.

Claim 11

A system according to claim 8, wherein said second detecting means comprises: (i) illuminating means for projecting first and second light beams from a light source to the first and second diffraction gratings in different directions; (ii) first signal detecting means for detecting a first interference light signal produced as a combination of diffraction light provided by the first light and diffraction light provided by the second light, both from the first diffraction grating; (iii) second signal detecting means for detecting a second interference light signal produced as a combination of diffraction light provided by the first light and diffraction light provided by the second light, both from the second diffraction grating; (iv) phase difference detecting means for detecting a phase difference between the first and second interference light signals; and (v) deviation determining means for determining relative positional deviation between the first and second diffraction gratings on the basis of the phase difference detected by said phase difference detecting means.

Claim 14

A method according to claim 10, wherein the pattern is provided by a diffraction grating.

Claim 15

A method according to claim 10, wherein the pattern is provided by a circuit pattern.

Claim 16

A method according to claim 10, wherein the two diffraction lights have diffraction orders of different signs.

Claim 17

A method according to claim 13, wherein the two diffraction lights have diffraction orders of the same absolute value.

Claim 18

A method according to claim 10, wherein the optical system projects light from a laser to the pattern obliquely.

Claim 21

A method according to claim 16, wherein said second detecting step comprises: (i) projecting first and second light beams from a light source to the first and second diffraction gratings in different directions; (ii) detecting a first interference light signal produced as a combination of diffraction light provided by the first light and diffraction light provided by the second light, both from the first diffraction grating; (iii) detecting a second interference light signal produced as a combination of diffraction light provided by the first light and diffraction light provided by the second light, both from the second diffraction grating; (iv) detecting a phase difference between the first and second interference light signals; and (v) determining relative positional deviation between the first and second diffraction gratings on the basis of the phase difference, as detected in said phase difference detecting step.

Claim 22

A combination for detecting rotational deviation of an object on which a device is to be formed, said combination comprising: a pattern provided on the object, the pattern being able to function as the device; a light source for providing light; detecting means for projecting the light from said light source to the pattern and for detecting at least two diffraction lights from the pattern, at a predetermined detection plane, wherein said detecting means images a beam waist of said light source on a light path from said pattern to the predetermined detection plane; and determining means for determining rotational deviation of the object with respect to a predetermined axis, on the basis of incidence positions of the diffraction lights upon the detection plane, as detected by said detecting means.

Claim 23

A combination for detecting rotational deviation of an object on which a device is to be formed, said combination comprising: a pattern provided on the object, the pattern being able to function as the device; a light source for providing light; detecting means for projecting the light from said light source to the pattern and for detecting at least two diffraction lights from the pattern, at a predetermined detection plane, wherein said detecting means images a beam waist of said light source on a light path from said pattern to the predetermined detection plane; and determining means for determining rotational deviation of the object with respect to a predetermined axis, on the basis of incidence positions of the diffraction lights upon the detection plane, as detected by said detecting means.

Claim 24

A combination according to claim 18, wherein the pattern is provided by a circuit pattern.

Claim 25

A combination according to claim 18, wherein the two diffraction lights have diffraction orders of different signs.

Claim 26

A combination according to claim 20, wherein the two diffraction lights have diffraction orders of the same absolute value.

Claim 27

A combination according to claim 18, wherein the light from the light source is projected to the pattern obliquely.

Claim 30

A method according to claim 23, wherein the pattern is provided by a circuit pattern.

Claim 31

A method according to claim 23, wherein the two diffraction lights have diffraction orders of different signs.

Claim 32

A method according to claim 25, wherein the two diffraction lights have diffraction orders of the same absolute value.

Claim 33

A method according to claim 23, wherein the light is projected to the pattern obliquely.