Surface inspection apparatus
First Claim
1. A surface inspection apparatus comprising:
- an illumination optical system for irradiating an inspection target object having its surface formed with a periodically repeated pattern with radiation for inspection;
a converging optical system for converging regularly reflected radiation from said inspection target object; and
an imaging device for detecting an image of said inspection target object by receiving the regularly reflected radiation converged by said converging optical system, wherein said surface inspection apparatus inspects the surface of said inspection target object on the basis of the image of said inspection target object that is detected by said imaging device, and an incident angle i and a wavelength λ
of the use-for-inspection illumination radiation with which said illumination optical system irradiates said inspection target object, are set to satisfy the following formula;
λ
/(sin i+1)≦
p where p is a pattern repetitive pitch.
1 Assignment
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Accused Products
Abstract
A surface inspection apparatus is constructed of an illumination unit for irradiating a wafer with illumination radiation for inspection, and a radiation receiving unit having a CCD imaging device for detecting an image of the wafer by converging regularly reflected radiation from the wafer. The wafer surface is inspected based on the image detected by the CCD imaging device. An incident angle i and a wavelength λ of the use-for-inspection illumination radiation with which the illumination unit irradiates the wafer, are set to satisfy the following conditional formula:
λ/(sin i+1)≦p (1)
where p is a pattern repetitive pitch.
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Citations
10 Claims
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1. A surface inspection apparatus comprising:
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an illumination optical system for irradiating an inspection target object having its surface formed with a periodically repeated pattern with radiation for inspection;
a converging optical system for converging regularly reflected radiation from said inspection target object; and
an imaging device for detecting an image of said inspection target object by receiving the regularly reflected radiation converged by said converging optical system, wherein said surface inspection apparatus inspects the surface of said inspection target object on the basis of the image of said inspection target object that is detected by said imaging device, and an incident angle i and a wavelength λ
of the use-for-inspection illumination radiation with which said illumination optical system irradiates said inspection target object, are set to satisfy the following formula;
λ
/(sin i+1)≦
pwhere p is a pattern repetitive pitch. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A surface inspection method used for a surface inspection apparatus comprising:
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at least two pieces of first and second use-for-inspection radiation sources each having a different wavelength of illumination radiation;
a converging optical system for converging regularly reflected radiation from an inspection target object having its surface irradiated with said use-for-inspection radiation source and formed with a periodically repeated pattern; and
an imaging device for detecting an image of said inspection target object by receiving the regularly reflected radiation converged by said converging optical system, said surface inspection apparatus inspecting the surface of said inspection target object on the basis of the image of said inspection target object which is detected by said imaging device, said method comprising;
a first imaging step of executing an imaging process based on the regularly reflected radiation by said imaging device in a way that sequentially changes an angle of said first use-for-inspection radiation source within a predetermined incident angle range;
a first storing step of storing such an angular position as to obtain a first predetermined regularly reflected radiation quantity by receiving the regularly reflected radiation in said first imaging step;
a second imaging step of executing the imaging process based on the regularly reflected radiation by said imaging device in a way that sequentially changes an angle of said second use-for-inspection radiation source within a predetermined incident angle range;
a second storing step of storing such an angular position as to obtain a second predetermined regularly reflected radiation quantity by receiving the regularly reflected radiation in said second imaging step;
a comparing step of comparing the first predetermined regularly reflected radiation quantity in said first storing step with the second predetermined regularly reflected radiation quantity in said second storing step; and
a selecting step of selecting, based on a compared result in said comparing step, one of the angular positions stored in said first and second storing steps, and selecting one of said first and second use-for-inspection radiation sources used for obtaining the selected angular position. - View Dependent Claims (8)
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9. A surface inspection method used for a surface inspection apparatus comprising:
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at least two pieces of first and second use-for-inspection radiation sources each having a different wavelength of illumination radiation;
a converging optical system for converging regularly reflected radiation from an inspection target object having its surface irradiated with said use-for-inspection radiation source and formed with a periodically repeated pattern; and
an imaging device for detecting an image of said inspection target object by receiving the regularly reflected radiation converged by said converging optical system, said surface inspection apparatus inspecting the surface of said inspection target object on the basis of the image of said inspection target object which is detected by said imaging device, said method comprising;
an inputting step of inputting a pitch of the periodic pattern;
a first imaging step of executing an imaging process based on the regularly reflected radiation by said imaging device in a way that sequentially changes an angle within such a range that an incident angle i of said first use-for-inspection radiation source satisfies the formula such as λ
1/(sin i+1)≦
P on the basis of the pitch P inputted in said inputting step and a wavelength λ
1 of said first use-for-inspection radiation source;
a first storing step of storing such an angular position as to obtain a first predetermined regularly reflected radiation quantity by receiving the regularly reflected radiation in said first imaging step;
a second imaging step of executing an imaging process based on the regularly reflected radiation by said imaging device in a way that sequentially changes an angle within such a range that an incident angle i of said second use-for-inspection radiation source satisfies the formula such as λ
2/(sin i+1)≦
P on the basis of the pitch P inputted in said inputting step and a wavelength λ
2 of said second use-for-inspection radiation source;
a second storing step of storing such an angular position as to obtain a second predetermined regularly reflected radiation quantity by receiving the regularly reflected radiation in said second imaging step;
a comparing step of comparing the first predetermined regularly reflected radiation quantity in said first storing step with the second predetermined regularly reflected radiation quantity in said second storing step; and
a selecting step of selecting, based on a compared result in said comparing step, one of the angular positions stored in said first and second storing steps, and selecting one of said first and second use-for-inspection radiation sources used for obtaining the selected angular position. - View Dependent Claims (10)
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Specification