SCANNING DIFFERENTIAL INTERFERENCE CONTRAST IN AN IMAGING SYSTEM DESIGN
First Claim
Patent Images
1. An apparatus comprising:
- at least one illumination source;
a stage configured to secure a wafer;
a TDI-CCD sensor;
a dark field/bright field sensor;
a field stop in a light path from the illumination source;
a polarizer in the light path, wherein the polarizer is configured to pass P polarized light and reflect S polarized light;
a Wollaston prism in the light path, wherein the Wollaston prism forms the P polarized light and the S polarized light;
a correction lens optic in the light path;
a mirror in the light path that receives the P polarized light and the S polarized light from the Wollaston prism; and
an objective lens assembly in the light path, wherein the correction lens optic, the mirror, and the objective lens assembly are configured to focus the P polarized light and the S polarized light onto the stage, wherein the P polarized light and the S polarized light are separated in a shear direction of the Wollaston prism, and wherein the P polarized light and the S polarized combine at the Wollaston prism.
3 Assignments
0 Petitions
Accused Products
Abstract
The inspection system includes an illumination source, a TDI-CCD sensor, and a dark field/bright field sensor. A polarizer receives the light from the light source. The light from the polarizer is directed at a Wollaston prism, such as through a half wave plate. Use of the TDI-CCD sensor and the dark field/bright field sensor provide high spatial resolution, high defect detection sensitivity and signal-to-noise ratio, and fast inspection speed.
0 Citations
20 Claims
-
1. An apparatus comprising:
-
at least one illumination source; a stage configured to secure a wafer; a TDI-CCD sensor; a dark field/bright field sensor; a field stop in a light path from the illumination source; a polarizer in the light path, wherein the polarizer is configured to pass P polarized light and reflect S polarized light; a Wollaston prism in the light path, wherein the Wollaston prism forms the P polarized light and the S polarized light; a correction lens optic in the light path; a mirror in the light path that receives the P polarized light and the S polarized light from the Wollaston prism; and an objective lens assembly in the light path, wherein the correction lens optic, the mirror, and the objective lens assembly are configured to focus the P polarized light and the S polarized light onto the stage, wherein the P polarized light and the S polarized light are separated in a shear direction of the Wollaston prism, and wherein the P polarized light and the S polarized combine at the Wollaston prism. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method comprising:
-
generating a light beam using an illumination source; directing the light beam from the illumination source through a field stop; directing the light beam from the field stop through a polarizer; directing the light beam from the polarizer to a Wollaston prism; directing the light beam from the Wollaston prism to a correction lens optic; directing the light beam from the correction lens optic to a mirror; directing the light beam toward a wafer on a stage through an objective lens assembly, wherein the correction lens optic, the mirror, and the objective lens assembly are configured to focus P polarized light and S polarized light from the Wollaston prism onto the stage, wherein the P polarized light and the S polarized light are separated in a shear direction of the Wollaston prism; splitting the light beam reflected from the wafer on the stage with a dichroic mirror into a first light beam and a second light beam; receiving the first light beam with a dark field/bright field sensor; combining the P polarized light and the S polarized light of the second light beam at the Wollaston prism; and receiving the second light beam from the Wollaston prism with a TDI-CCD sensor. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
-
Specification