US 2007/0182958 A1Published application

Apparatus and method for wafer surface defect inspection

OwnerYuji Manabe, Takahiro Jinguinventors

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Abstract

A beam emitted from a first light source is shed on the surface of a rotating wafer to form a beam spot. Scattered light arising from foreign matter and other defects on the surface of the wafer is detected in a plurality of directions and output in the form of a signal. Vertical movement of the wafer surface is detected by using white light or broadband light from a second light source. The position of the beam spot on the wafer surface is corrected in accordance with the information on the detected vertical movement for the purpose of minimizing a coordinate error that may arise from the vertical movement of the wafer surface. Further, the emission direction and emission position of light generated from the first light source are corrected to minimize a coordinate error that may arise from variations of the first light source. These corrections are made to enhance the accuracy of the coordinates of detected foreign matter and other defects. Moreover, the illumination beam spot diameter is corrected to prevent the detection sensitivity and foreign matter coordinate detection error from varying from one apparatus to another.

Claims25

Dependent claims

A wafer surface defect inspection apparatus comprising:

a stage for rotating a wafer;
an irradiation optics for forming a vertical irradiation beam spot by irradiating the surface of the wafer that is rotated by the stage, from a substantially vertical direction with a beam emitted from a first light source, changing the emitted beam, and forming an oblique irradiation beam spot by irradiating the surface of the wafer that is rotated by the stage for scanning purposes, from an oblique direction that is inclined from vertical;
a detection optics for collecting scattered light arising from foreign matter and other defects on the surface of the wafer, receiving the collected scattered light, and outputting a signal representing the received scattered light when the irradiation optics forms the beam spots on the surface of the wafer;
a height detection optics for shedding white light or broadband light, which is irradiated from a second light source, onto the vicinity of the oblique irradiation beam spot formed on the surface of the wafer by the irradiation optics, causing a detector to receive the resulting reflected light, and detecting the surface height of the wafer in the vicinity of the oblique irradiation beam spot;
and
beam spot position correction means for correcting the position of the oblique irradiation beam spot that is formed on the wafer surface by the irradiation optics, in accordance with the information on the wafer's surface height prevailing in the vicinity of the oblique irradiation beam spot that is detected by the height detection optics.

3 more elements

A wafer surface defect inspection apparatus comprising:

a stage for rotating a wafer;
an irradiation optics for forming a vertical irradiation beam spot by irradiating the surface of the wafer that is rotated by the stage, from a substantially vertical direction with a beam emitted from a first light source, changing the emitted beam, and forming an oblique irradiation beam spot by irradiating the surface of the wafer that is rotated by the stage for scanning purposes, from an oblique direction that is inclined from vertical;
a detection optics for collecting scattered light arising from foreign matter and other defects on the surface of the wafer, receiving the collected scattered light, and outputting a signal representing the received scattered light when the irradiation optics forms the beam spots on the surface of the wafer;
beam spot detection means for detecting the positional displacement and dimensions of the vertical irradiation beam spot or oblique irradiation beam spot that is formed on the wafer surface by the irradiation optics;
an emitted beam correction optics for correcting the emission direction and emission position of a beam emitted from the first light source that is included in the irradiation optics;
and
beam detection means for monitoring a beam position immediately after the emitted beam correction optics,
wherein the emitted beam correction optics corrects the emission direction and emission position of a beam emitted from the first light source in accordance with at least the positional displacement information on the vertical irradiation beam spot or oblique irradiation beam spot detected by the beam spot detection means and at least the positional displacement information on a beam that is emitted from the first light source and detected by the beam detection means.

5 more elements

A wafer surface defect inspection method comprising:

a scanning step of rotating a wafer by driving a stage;
an irradiation step of forming a vertical irradiation beam spot by causing an irradiation optics to irradiate the surface of the wafer that is rotated in the scanning step, from a substantially vertical direction with a beam emitted from a first light source, change the emitted beam, and form an oblique irradiation beam spot by irradiating the surface of the wafer that is rotated in the scanning step for scanning purposes, from an oblique direction that is inclined from vertical;
a detection step of causing a detection optics to collect scattered light arising from foreign matter and other defects on the surface of the wafer, receive the collected scattered light, and output a signal representing the received scattered light when the beam spots is formed on the surface of the wafer in the irradiation step;
a height detection step of shedding white light or broadband light, which is irradiated from a second light source, onto the vicinity of the oblique irradiation beam spot that is formed on the surface of the wafer in the irradiation step, causing a detector to receive the resulting reflected light, and detecting the surface height of the wafer in the vicinity of the oblique irradiation beam spot;
and
a beam spot position correction step of correcting the position of the oblique irradiation beam spot that is formed on the wafer surface in the irradiation step, in accordance with the information on the wafer's surface height prevailing in the vicinity of the oblique irradiation beam spot, which is detected in the height detection step.

3 more elements

Dependencies are inferred from the claim text.