US 2003/0189703 A1Published application

Image pickup apparatus and defect inspection apparatus for photomask

AssigneeLasertec Corporation

InventorsMakoto Yonezawa, Haruhiko Kusunose

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Abstract

The present invention has a configuration in which a line confocal optical system is formed and plural times of illumination by lines of lights are carried out. Particularly, in the present invention, the diffraction grating 32 produces the m×n number of sub beams. Further, the m×n number of sub beams are deflected by the acoustic optical element 33 so that their irradiation areas are to be continuous. Therefore, since the beam carries out scanning using the m×n number of sub beams, scanning can be completed in a short time.

Claims6

Dependent claims

An image pickup apparatus comprising:

a sample stage moving a sample whose image is to be taken in a first direction;
a light source emitting a light beam;
a diffraction grating generating m×n number of sub beams at predetermined intervals along a direction corresponding to the first direction and a second direction perpendicular to the first direction from said light beam;
a beam deflection device deflecting said m×n number of sub beams in the first direction;
an image sensor receiving a transmitted light or a reflected light from a sample, having plural light receiving elements arranged in a two-dimensional array along the first and second directions, successively transferring charges stored in each line of said light receiving elements arranged in the first direction, line by line, at a predetermined line transfer speed, and successively outputting the charges stored in said light receiving elements;
a spatial filter arranged between said sample stage and said image sensor, and having plural slits formed at a predetermined pitch along the second direction and extending in the first direction;
and
a drive control circuit controlling drive of said image sensor and said beam deflection device;
wherein a reflected light or a transmitted light of said m×n number of sub beams scanning a surface of said sample enters into said image sensor through each slit of said spatial filter;
a moving speed of said sample stage and a charge transfer speed of said image sensor are set so that a time interval during which said sample moves from a position into which an i-th line of said sub beam enters, to a position into which an i+1-th line of said sub beam adjacent to the second direction enters, and a time interval during which said image sensor transfers the charge stored in a line of said light receiving elements into which a light having passed through an i-th slit of said spatial filter enters, to a line of said light receiving elements into which an illumination light having passed through an adjoining i+1th slit enters, become equal to each other;
and
said drive control circuit controls drive of said beam deflection device so that irradiation areas formed by the movement of said m×n number of sub beams are to be continuous in the first direction.

9 more elements

Dependencies are inferred from the claim text.

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Abstract

An image pickup apparatus comprising:

a sample stage moving a sample whose image is to be taken in a first direction;
a light source emitting a light beam;
a diffraction grating generating m×n number of sub beams at predetermined intervals along a direction corresponding to the first direction and a second direction perpendicular to the first direction from said light beam;
a beam deflection device deflecting said m×n number of sub beams in the first direction;
an image sensor receiving a transmitted light or a reflected light from a sample, having plural light receiving elements arranged in a two-dimensional array along the first and second directions, successively transferring charges stored in each line of said light receiving elements arranged in the first direction, line by line, at a predetermined line transfer speed, and successively outputting the charges stored in said light receiving elements;
a spatial filter arranged between said sample stage and said image sensor, and having plural slits formed at a predetermined pitch along the second direction and extending in the first direction;
and
a drive control circuit controlling drive of said image sensor and said beam deflection device;
wherein a reflected light or a transmitted light of said m×n number of sub beams scanning a surface of said sample enters into said image sensor through each slit of said spatial filter;
a moving speed of said sample stage and a charge transfer speed of said image sensor are set so that a time interval during which said sample moves from a position into which an i-th line of said sub beam enters, to a position into which an i+1-th line of said sub beam adjacent to the second direction enters, and a time interval during which said image sensor transfers the charge stored in a line of said light receiving elements into which a light having passed through an i-th slit of said spatial filter enters, to a line of said light receiving elements into which an illumination light having passed through an adjoining i+1th slit enters, become equal to each other;
and
said drive control circuit controls drive of said beam deflection device so that irradiation areas formed by the movement of said m×n number of sub beams are to be continuous in the first direction.

9 more elements