WE CLAIM:
1. A three-dimensional measurement device, comprising:
a predetermined optical system configured to split predetermined incident light into two lights, to radiate one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and to recombine the two lights to combined light and emit the combined light;
an irradiation unit configured to emit predetermined light that is made to enter the predetermined optical system!
an imaging unit configured to take an image of output light emitted from the predetermined optical system! and
an image processor configured to perform three-dimensional measurement with regard to a predetermined measurement area of the measured object, based on an interference fringe image obtained by imaging by the imaging unit, wherein
the image processor comprises^
an image data obtaining unit configured to obtain intensity image data at a predetermined position in an optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on an interference fringe image with regard to the measurement area obtained by imaging by the imaging unit!
a phase information obtaining unit configured to obtain phase information of light at the predetermined position in the optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on the interference fringe image with regard to the measurement area obtained by imaging by the imaging unit!
a focusing determination unit configured to determine whether the intensity image data is in a focusing state that satisfies a predetermined condition, based on the intensity image data at the predetermined position in the optical axis direction with regard to a predetermined coordinate position in the measurement area obtained by the image data obtaining unit!
an order specifying unit configured to specify an order corresponding to the predetermined position in the optical axis direction, as an order with regard to the predetermined coordinate position, among orders

determined at predetermined measurement range intervals in the optical axis direction, when it is determined that the intensity image data at the predetermined position in the optical axis direction with regard to the predetermined coordinate position is in the focusing state, based on a determination result of the focusing determination unit; and
a three-dimensional measurement unit configured to perform three-dimensional measurement with regard to the predetermined coordinate position, based on phase information with regard to the predetermined coordinate position obtained by the phase information obtaining unit and the order with regard to the predetermined coordinate position specified by the order specifying unit.
2. A three-dimensional measurement device, comprising:
a predetermined optical system configured to split predetermined incident light into two lights, to radiate one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and to recombine the two lights to combined light and emit the combined light;
an irradiation unit configured to emit predetermined light that is made to enter the predetermined optical system;
an imaging unit configured to take an image of output light emitted from the predetermined optical system; and
an image processor configured to perform three-dimensional measurement with regard to a predetermined measurement area of the measured object, based on an interference fringe image obtained by imaging by the imaging unit, wherein
the image processor comprises^
an image data obtaining unit configured to obtain multiple sets of intensity image data at a predetermined position in an optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on an interference fringe image with regard to the measurement area obtained by imaging by the imaging unit, wherein the multiple sets of the intensity image data are obtained at predetermined measurement range intervals of a number n of periods in at least a predetermined range in the optical axis direction, (where n is a natural number equal to or greater than l);

a focusing position determination unit configured to determine a predetermined focusing position in the optical axis direction with regard to a predetermined coordinate position in the measurement area, based on the multiple sets of the intensity image data with regard to the predetermined coordinate position obtained by the image data obtaining unit!
an order specifying unit configured to specify an order corresponding to the focusing position in the optical axis direction with regard to the predetermined coordinate position determined by the focusing position determination unit, as an order with regard to the predetermined coordinate position, among orders determined at the measurement range intervals in the optical axis direction!
a phase information obtaining unit configured to obtain phase information of light at the predetermined position in the optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on the interference fringe image with regard to the measurement area obtained by imaging by the imaging unit! and
a three-dimensional measurement unit configured to perform three-dimensional measurement with regard to the predetermined coordinate position, based on phase information with regard to the predetermined coordinate position obtained by the phase information obtaining unit and the order with regard to the predetermined coordinate position specified by the order specifying unit.
3. A three-dimensional measurement device, comprising:
a predetermined optical system configured to split predetermined incident light into two lights, to radiate one of the two lights as measurement light to a measured object and the other of the two lights as reference light to a reference surface, and to recombine the two lights to combined light and emit the combined light!
an irradiation unit configured to emit predetermined light that is made to enter the predetermined optical system!
an imaging unit configured to take an image of output light emitted from the predetermined optical system! and
an image processor configured to perform three-dimensional measurement with regard to a predetermined measurement area of the

measured object, based on an interference fringe image obtained by imaging by the imaging unit, wherein
the image processor comprises^
a first image data obtaining unit configured to obtain multiple sets of intensity image data at a predetermined position in an optical axis direction with regard to a specific area that is a preset part in the measurement area by reconstruction based on the interference fringe image obtained by imaging by the imaging unit, wherein the multiple sets of the intensity image data are obtained at predetermined measurement range intervals of a number n of periods in at least a first range in the optical axis direction, (where n is a natural number equal to or greater than l);
a first focusing position determination unit configured to determine a predetermined focusing position in the optical axis direction with regard to the specific area, based on the multiple sets of the intensity image data with regard to the specific area obtained by the first image data obtaining unit;
a second image data obtaining unit configured to obtain multiple sets of intensity image data at the predetermined position in the optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on the interference fringe image with regard to the measurement area obtained by imaging by the imaging unit, wherein the multiple sets of the intensity image data are obtained at predetermined measurement range intervals of a number n of periods in at least a second range in the optical axis direction, which is set on a basis of the focusing position in the optical axis direction in the specific area, (where n is a natural number equal to or greater than l);
a second focusing position determination unit configured to determine a predetermined focusing position in the optical axis direction with regard to a predetermined coordinate position in the measurement area, based on the multiple sets of the intensity image data with regard to the predetermined coordinate position obtained by the second image data obtaining unit;
an order specifying unit configured to specify an order corresponding to the focusing position in the optical axis direction with regard to the predetermined coordinate position determined by the second focusing position determination unit, as an order with regard to the

predetermined coordinate position, among orders determined at the measurement range intervals in the optical axis direction!
a phase information obtaining unit configured to obtain phase information of light at the predetermined position in the optical axis direction with regard to each coordinate position in the measurement area by reconstruction based on the interference fringe image with regard to the measurement area obtained by imaging by the imaging unit! and
a three-dimensional measurement unit configured to perform three-dimensional measurement with regard to the predetermined coordinate position, based on phase information with regard to the predetermined coordinate position obtained by the phase information obtaining unit and the order with regard to the predetermined coordinate position specified by the order specifying unit.
4. The three-dimensional measurement device according to any one
of claims 1 to 3,
wherein the reconstruction is performed by obtaining complex amplitude data with regard to the predetermined position in the optical axis direction, based on the interference fringe image.
5. The three-dimensional measurement device according to any one
of claims 1 to 4, further comprising:
a phase shift unit configured to provide a relative phase difference between the reference light and the measurement light, wherein
the image processor is configured to perform measurement with regard to a predetermined measurement area of the measured object, based on multiple interference fringe images obtained by the imaging unit that takes images of the output light subjected to multiple different phase shifts by the phase shift unit.
6. The three-dimensional measurement device according to any one
of claims 1 to 5,
wherein the irradiation unit comprises:
a first irradiation unit configured to emit first light that includes polarized light of a first wavelength and that is made to enter the predetermined optical system! and

a second irradiation unit configured to emit second light that includes polarized light of a second wavelength and that is made to enter the predetermined optical system, and the imaging unit comprises:
a first imaging unit configured to take an image of output light with regard to the first light that is emitted from the predetermined optical system when the first light enters the predetermined optical system! and
a second imaging unit configured to take an image of output light with regard to the second light that is emitted from the predetermined optical system when the second light enters the predetermined optical system.
7. The three-dimensional measurement device according to any one of claims 1 to 6,
wherein the measured object is a wafer substrate with a bump formed thereon.