Apparatus and method for metrology
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsBaohua Niu, Ji-Feng Ying, David Hung-I Su
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Abstract
A method of performing metrology analysis of a thin film includes coupling a radiation into an optical element disposed adjacent to a surface of the thin film. The radiation is coupled such that the radiation is totally internally reflected at an interface between the optical element and the thin film. An evanescent radiation generated at the interface penetrates the thin film. The method furthers include analyzing the evanescent radiation scattered by the thin film to obtain properties of the thin film.
Claims19
An apparatus for metrology analysis of a thin film, the apparatus comprising:
- an optical element disposed adjacent to a surface of the thin film and configured to totally internally reflect a radiation from a radiation source at an interface between the optical element and the thin film such that an evanescent radiation is generated at the interface penetrating the thin film, the optical element including a radiation coupler disposed adjacent to the surface of the thin film and a high numerical aperture (NA) lens;
- one or more dichroic mirrors to split the evanescent radiation into a first radiation in a first direction and a second radiation in a second direction;
- a first detector configured to analyze the first radiation in the first direction to obtain properties of the thin film;
- and
- a second detector configured to optically observe the second radiation in the second direction to observe evanescent field Rayleigh scattering,
- wherein the optical element comprises at least one selected from the group consisting of a liquid immersion lens, a centric solid immersion lens (cSIL) and an achromatic solid immersion lens (aSIL),
- wherein the optical element comprises a radiation coupler disposed adjacent to the surface of the thin film and a high numerical aperture (NA) lens, and
- wherein the high numerical aperture (NA) lens includes an aspheric lens to compensate for aberrations.
A method of performing metrology analysis of a thin film, the method comprising:
- coupling a radiation into an optical element disposed adjacent to a surface of the thin film such that the radiation is totally internally reflected at an interface between the optical element and the thin film and an evanescent radiation generated at the interface penetrates the thin film, the optical element including a radiation coupler disposed adjacent to the surface of the thin film and a high numerical aperture (NA) lens;
- splitting the evanescent radiation scattered by the thin film using one or more dichroic mirrors into a first radiation in a first direction and a second radiation in a second direction;
- analyzing the first radiation by a first detector to obtain properties of the thin film;
- and
- optically observing the second radiation by a second detector to observe evanescent field Rayleigh scattering,
- wherein the high numerical aperture lens includes an aspheric lens to compensate for aberrations.
A method of obtaining properties of a thin film disposed on a solid substrate, the thin film having a front surface, the method comprising:
- placing an optical element having a higher refractive index than the thin film over the thin film at a front surface side of the thin film, the optical element including a radiation coupler disposed adjacent to the surface of the thin film and a high numerical aperture (NA) lens;
- placing a radiation source in the front surface side of the thin film;
- coupling a radiation from the radiation source into the optical element such that the radiation is totally internally reflected at an interface between the optical element and the thin film and an evanescent radiation generated at the interface penetrates the thin film;
- splitting the evanescent radiation scattered by the thin film using one or more dichroic mirrors into a first radiation in a first direction and a second radiation in a second direction;
- detecting the evanescent radiation scattered by the thin film by a first detector and collected by an immersion lens disposed on the front surface side of the thin film, wherein the radiation and the evanescent radiation scattered by the thin film are in the same side;
- and
- analyzing the detected evanescent radiation scattered by the thin film by a second detector to obtain properties of the thin film,
- wherein the high numerical aperture (NA) lens includes an aspheric lens to compensate for aberrations.
Dependencies are inferred from the claim text.