Apparatus for determining an overlay error and critical dimensions in a semiconductor structure by means of scatterometry
First Claim
1. An apparatus for obtaining information on critical dimensions and overlay accuracy of features formed in a semiconductor structure, wherein the semiconductor structure includes a first diffracting pattern oriented with respect to a first direction and a second diffracting pattern oriented with respect to a second direction, the apparatus comprising:
- a light source for emitting at least one light beam;
a first plurality of deflecting elements defining a first optical path in a first plane of incidence corresponding to the first direction, and a second plurality of deflecting elements defining a second optical path in a second plane of incidence corresponding to the second direction; and
a detector optically connectable to the first and second optical paths to receive a light beam diffracted by the first and the second diffracting patterns, respectively.
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Abstract
An apparatus for obtaining information on critical dimensions and overlay accuracy of features in a semiconductor structure comprises a light source, a detector and an optical means defining a first optical path and a second optical path. The first optical path and the second optical path are oriented in correspondence with the respective orientations of diffracting patterns provided on the semiconductor structure to obtain the required information without the necessity of rotating the semiconductor structure. This insures a significantly higher throughput.
47 Citations
16 Claims
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1. An apparatus for obtaining information on critical dimensions and overlay accuracy of features formed in a semiconductor structure, wherein the semiconductor structure includes a first diffracting pattern oriented with respect to a first direction and a second diffracting pattern oriented with respect to a second direction, the apparatus comprising:
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a light source for emitting at least one light beam;
a first plurality of deflecting elements defining a first optical path in a first plane of incidence corresponding to the first direction, and a second plurality of deflecting elements defining a second optical path in a second plane of incidence corresponding to the second direction; and
a detector optically connectable to the first and second optical paths to receive a light beam diffracted by the first and the second diffracting patterns, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for obtaining information on critical dimensions and overlay accuracy of features formed in a semiconductor structure, wherein the semiconductor structure includes a first diffracting pattern oriented with respect to a first direction and a second diffracting pattern oriented with respect to a second direction, the apparatus comprising:
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a light source for emitting at least one light beam;
at least one optical fiber to define a first optical path and second optical path; and
a detector optically connectable to the first and second optical paths to receive a light beam diffracted by the first and the second diffracting patterns, respectively. - View Dependent Claims (14, 15, 16)
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Specification