Apparatus and method for inspecting defects

A defect inspection apparatus, comprising:

• a stage that is caused to travel after a substrate to be inspected has been rested on the stage, the substrate having a circuit pattern formed thereon;
• an irradiation optical system that guides a beam flux emitted from a laser light source from a principal optical path to a first optical path, a second optical path, and a third optical path;
• focuses the beam flux that has been guided as a first beam flux to the first optical path into a first slit-shaped beam, from a clockwise direction having a required inclination extending horizontally with respect to an X-axis direction of a major straight-line group of the circuit pattern and at a required angle of inclination to the surface of the substrate to be inspected, the first slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the first slit-shaped beam;
• irradiates the substrate with the first slit-shaped beam such that the longitudinal direction of the first slit-shaped beam is at a substantially right angle to a traveling direction of the stage;
• focuses the beam flux that has been guided as a second beam flux to the second optical path into a second slit-shaped beam, from a counterclockwise direction having a required inclination extending horizontally with respect to the X-axis direction and at a required angle of inclination to the surface of the substrate to be inspected, the second slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the second slit-shaped beam;
• irradiates the substrate with the second slit-shaped beam such that the longitudinal direction of the second slit-shaped beam is at a substantially right angle to the traveling direction of the stage;
• focuses the beam flux that has been guided as a third beam flux to the third optical path into a third slit-shaped beam, from the X-axis direction and at a required angle of inclination to the surface of the substrate to be inspected, the third slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the third slit-shaped beam;
• and
• irradiates the substrate with the third slit-shaped beam such that the longitudinal direction of the third slit-shaped beam is at a substantially right angle to the traveling direction of the stage;
• a detection optical system that uses an objective lens to converge reflected/scattered light obtained from contamination or other defects present on the substrate that has been irradiated with the slit-shaped beam, and uses an image sensor to receive the reflected/scattered light that has been converged, convert the received light into a signal, and detect the signal;
• and
• an image processor that extracts, on the basis of the signal that has been detected by the image sensor of the detection optical system, a signal indicative of the defect such as contamination;
• wherein the irradiation optical system includes:
• a first mirror that reflects and directs downward the first beam flux that has been guided to the first optical path;
• a first cylindrical lens and a first inclined mirror each for focusing the beam flux that has been directed downward by the first mirror onto the substrate to be inspected, from the clockwise direction having the required inclination extending horizontally and at the required inclination angle, as the first slit-shaped beam;
• a second mirror that reflects and directs downward the second beam flux that has been guided to the second optical path;
• a second cylindrical lens and a second inclined mirror for focusing the beam flux that has been directed downward by the second mirror onto the substrate to be inspected, from the counterclockwise direction having the required inclination extending horizontally and at the required inclination angle, as the second slit-shaped beam;
• a third mirror that reflects and directs downward the third beam flux that has been guided to the third optical path;
• and
• a third cylindrical lens and a third inclined mirror for focusing the beam flux that has been directed downward by the third mirror onto the substrate to be inspected, from the X-axis direction extending horizontally and at the required inclination angle, as the third slit-shaped beam.

A defect inspection method comprising:

• a stage traveling step of causing a stage to travel after a substrate to be inspected has been rested on the stage, the substrate having a circuit pattern formed thereon;
• a irradiation step of guiding a beam flux emitted from a laser light source from a principal optical path to a first optical path or a second optical path, focusing the beam flux that has been guided to the first or second optical path into a slit-shaped beam, from a direction having a required inclination extending horizontally with respect to a major straight-line group of the circuit pattern and at a required angle of inclination to the surface of the substrate to be inspected, the slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the slit-shaped beam, and irradiating the substrate with the slit-shaped beam such that the longitudinal direction is at a substantially right angle to a traveling direction of the stage;
• a detection step of converging reflected/scattered light obtained from contamination or defects present on the substrate that has been irradiated with the slit-shaped beam in the irradiation step by using an objective lens, receiving the reflected/scattered light that has been converged by using an image sensor, converting the received light into a signal, and detecting the signal;
• and
• an image processing step of extracting a signal indicative of the defect such as contamination on the basis of the signal that has been detected by the image sensor of the detection optical system,
• wherein in the irradiation step,
• a mirror is used to reflect downward the beam flux that has been guided to the first or second optical path;
• and
• a cylindrical lens and an inclined mirror are used to focus the beam flux that has been directed downward by the downward reflecting mirror onto the substrate, as the slit-shaped beam, from the direction having the required inclination extending horizontally and at the required inclination angle.

A defect inspection method, comprising:

• a stage traveling step of causing a stage to travel after a substrate to be inspected has been rested on the stage, the substrate having a circuit pattern formed thereon;
• an irradiation step including
• a first substep of guiding a beam flux emitted from a laser light source from a principal optical path to a first optical path, a second optical path, and a third optical path,
• a second substep of focusing a first beam flux that has been guided to the first optical path into a first slit-shaped beam, from a clockwise direction having a required inclination extending horizontally with respect to a major straight-line group of the circuit pattern and at a required angle of inclination to the surface of the substrate to be inspected, the first slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the first slit-shaped beam, and then irradiating the substrate with the first slit-shaped beam such that the longitudinal direction of the first slit-shaped beam is at a substantially right angle to a traveling direction of the stage,
• a third substep of focusing a second beam flux that has been guided to the second optical path into a second slit-shaped beam, from a counterclockwise direction having a required inclination extending horizontally with respect to the X-axis direction and at a required angle of inclination to the surface of the substrate, the second slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the second slit-shaped beam, and then irradiating the substrate with the second slit-shaped beam such that the longitudinal direction of the second slit-shaped beam is at a substantially right angle to the traveling direction of the stage, and
• a fourth substep of focusing a third beam flux that has been guided to the third optical path into a third slit-shaped beam, from the X-axis direction and at a required angle of inclination to the surface of the substrate, the third slit-shaped beam being formed up by fluxes of light that are substantially parallel in a longitudinal direction of the third slit-shaped beam, and then irradiating the substrate with the third slit-shaped beam such that the longitudinal direction of the third slit-shaped beam is at a substantially right angle to the traveling direction of the stage;
• a detection step of converging reflected/scattered light obtained from contamination or defects present on the substrate that has been irradiated with the slit-shaped beam in the irradiation step by using an objective lens, receiving the reflected/scattered light that has been converged by using an image sensor, converting the received light into a signal, and detecting the signal;
• and
• an image processing step of extracting a signal indicative of the defect such as contamination on the basis of the signal that has been detected by the image sensor of the detection optical system, wherein
• in the second substep of the irradiation step, a first mirror is used to reflect downward the first beam flux that has been guided to the first optical path, and a first cylindrical lens and a first inclined mirror are used to focus the first beam flux that has been directed downward by the first mirror onto the substrate, as the first slit-shaped beam, from the direction having the required inclination extending horizontally and at the required inclination angle;
• in the third substep of the irradiation step, a second mirror is used to reflect downward the second beam flux that has been guided to the second optical path, and a second cylindrical lens and a second inclined mirror are used to focus the second beam flux that has been directed downward by the second mirror onto the substrate, as the second slit-shaped beam, from the clockwise direction having the required inclination extending horizontally and at the required inclination angle;
• and
• in the fourth substep of the irradiation step, a third mirror is used to reflect downward the third beam flux that has been guided to the third optical path, and a third cylindrical lens and a third inclined mirror are used to focus the third beam flux that has been directed downward by the third mirror onto the substrate, as the third slit-shaped beam, from the counterclockwise direction having the required inclination extending horizontally and at the required inclination angle.