Radiant energy – Inspection of solids or liquids by charged particles – Electron probe type
Reexamination Certificate
1999-11-10
2001-01-09
Anderson, Bruce C. (Department: 2881)
Radiant energy
Inspection of solids or liquids by charged particles
Electron probe type
C250S307000
Reexamination Certificate
active
06172365
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for obtaining an image or a waveform representing a physical property of an object such as a semiconductor wafer with an electron beam, and comparing the image or waveform with design information or an image obtained behorehand to judge a defect, measure the dimension of a specific place, shape information or the fabrication condition of an object such as a semiconductor wafer, or display an image, and relates to an inspected wafer and its fabrication line in the case where the wafer is the object in the apparatus.
A conventional method using an electron beam to judge a defect, measure shape information or the fabrication condition of an object such as a semiconductor wafer, or display an image is described in JP-A-5-258703 (U.S. Pat. No. 5,502,306), for example. The conventional method includes the steps of detecting secondary electrons generated at the time of exposure with an electron beam under the same condition, conducting scanning with the electron beam, obtaining thereby an image of secondary electrons, and judging a defect on the basis of the image.
It is now assumed that an object is formed by predetermined materials A and B. In the case where a certain acceleration voltage Eb of the electron beam is used, the secondary electron yield ratio &eegr; of the material A is largely different from that of the material B. In this case, a secondary electron image contrast is obtained, and inspection between the material A and the material B is possible. In the case where a specific acceleration voltage Ea is used, however, the secondary electron yield ratio &eegr; of the material A becomes equal to that of the material B. In this case, there is little contrast in an obtained secondary electron image and the image cannot be observed. In the conventional technique, due regard is not paid to such a charge-up phenomenon for each material to be observed.
SUMMARY OF THE INVENTION
In view of the above described problem, an object of the present invention is to provide an electron beam inspection method, and apparatus, for reducing the charge-up phenomenon caused when an object is exposed to an electron beam, obtaining a high-contrast signal representing a physical property by using secondary electrons or back-scattered electrons obtained from the object, and making it possible to inspect a minute deffect at high speed and with high reliability.
Another object of the present invention is to provide an electron beam inspection method, and apparatus, for adapting the inspection condition to the charge-up phenomenon caused when an object is exposed to an electron beam, conducting inspection or measurement on the basis of an image signal representing a physical property by using secondary electrons or back-scattered electrons obtained from the object, and making it possible to inspect a minute deffect at high speed and with high reliability.
Another object of the present invention is to provide an electron beam inspection method, and apparatus, for making it possible to inspect minute resist patterns and insulator patterns which are apt to be charged, with high reliability.
A further object of the present invention is to provide a semiconductor fabrication method and its fabrication line in which minute pattern defects on a semiconductor substrate such as a semiconductor wafer are inspected to improve the yield.
In order to achieve the above described objects, in accordance with the present invention, an electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and displaying a signal representing the detected physical change on display means.
In accordance with the present invention, a electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object according to a kind of a section structure on a surface of the object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object according to at least a kind of a material on a surface of the object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object according to a change of a section structure on a surface of the object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of controlling an acceleration voltage of an electron beam and an electric field in neighborhood of an object according to a kind or a change of a section structure on a surface of the object, exposing the object to the electron beam with the controlled acceleration voltage, detecting in a sensor a physical change generated from the object in response to the controlled electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of presetting a proper acceleration voltage of an electron beam and a proper electric field in neighborhood of an object so as to correspond to a charge-up phenomenon on a surface of an object, exposing the object to the electron beam in such a state that the acceleration voltage is controlled to become the preset acceleration voltage, detecting in a sensor a physical change generated from the object in response to the electric field controlled to become the preset electric field, and conducting inspection or measurement of the object on the basis of a signal representing the detected physical change.
In accordance with the present invention, an electron beam inspection method includes the steps of presetting a proper acceleration voltage of an electron beam and a proper electric field in neighborhood of an object so as to correspond to a charge-up phenomenon on a surface of an object according to a kind or a change of a section structure on the surface of the object, exposing the object to the electron beam in such a state that the acceleration voltage is controlled to become the preset acceleration voltage, dete
Hiroi Takashi
Kuni Asahiro
Matsuyama Yukio
Nozoe Mari
Shinada Hiroyuki
Anderson Bruce C.
Antonelli Terry Stout & Kraus LLP
Hitachi. Ltd.
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