In-line angular optical multi-point scatterometry for nanomanufacturing systems
A method and system for high-speed 2Θ multi-point scatterometry is disclosed. The method includes directing a laser beam from a laser light source to a collimation optical system that collimates the laser beam to a collimated laser beam; adjusting a polarization of the collimated laser beam using a polarization control optics; directing the collimated laser beam that is polarized by a first optical system to illuminate a focal area on a sample surface; receiving reflected light from the focus of the laser light source at the sample surface by a second optical system; detecting the reflected light by a detector system to produce detection signals; and processing the detection signals to measure parameters of the sample surface.
1. A method for high-speed 2θ multi-point scatterometry comprising:
collimating a laser beam from a laser light source;
adjusting a polarization of the collimated laser beam using a polarization control optics;
illuminating a multiplicity of focal areas along a line on a sample surface, wherein angles of incidence of illumination of each of the multiplicity of focal areas are dynamically varied in a direction perpendicular to the line of the focal areas by a first optical system;
receiving light reflected at the dynamically varied angles of incidence of the illumination from the multiplicity of focal areas at the sample surface by a second optical system;
detecting the reflected light at the dynamically varied angles of incidence of the illumination from the multiplicity of focal areas by a detector system to produce detection signals; and
recording and processing the detection signals to measure parameters of the sample surface.
2. The method of claim 1 , further comprising translating the first optical system and the second optical system across the sample surface to cover additional regions of the sample surface.
3. The method of claim 1 , wherein additional polarization control optics are included in the second optical system.
4. The method of claim 1 , wherein the laser light source is composed of multiple individual lasers at different wavelengths with the beams from each laser optically combined into a single beam and wherein the detection system is configured to separately record the detection signals at the different wavelengths.
5. The method of claim 1 , wherein the first optical system comprises a first resonant scanner with a first rotation axis to provide dynamical variation of the angles of incidence of the illumination of multiple focal areas of the sample surface.
6. The method of claim 5 , wherein the first optical system comprises a second resonant scanner with a second rotation axis oriented in a perpendicular direction to the first rotation axis of the first resonant scanner to provide the multiplicity of focal areas of illumination of the sample surface.
7. The method of claim 5 , wherein the first optical system comprises a diffraction grating to provide the multiplicity of focal areas of illumination of the sample surface wherein diffracted orders from the diffraction grating are aligned along the rotation axis of the first resonant scanner.
8. The method of claim 7 , wherein the detector system comprises a number of independent detectors that match a number of multiple laser beams.
9. The method of claim 5 , wherein the first optical system comprises optics to expand the collimated beam in one direction along the rotation axis of the first resonant scanner.
10. The method of claim 5 , wherein the sample surface is patterned with a 1D grating and the first optical system is adjusted so that the line between the multiplicity of focal areas is parallel to the lines of the grating.
11. The method of claim 10 , wherein the first optical system and the second optical systems are rotated on an axis normal to the sample surface to allow for conical diffraction measurements.
12. The method of claim 1 , wherein the first optical system comprises a first one-dimensional parabolic mirror and the second optical system comprises a second one-dimensional parabolic mirror.
13. The method of claim 1 , wherein the first optical system comprises a first acylindrical lens and the second optical system comprises a second acylindrical lens.
14. The method of claim 1 , wherein the laser light source is a single laser.
15. A system for high-speed 2θ multi-point scatterometry comprising:
a multiplicity of modules, each module comprising:
a first optical system comprising one or more first optical elements that are configured to illuminate a focal area of a sample surface with a polarized laser beam, wherein an angle of incidence of illumination is dynamically varied by a first optical system;
a second optical system comprising one or more second optical elements that are configured receiving light reflected at the dynamically varied angles of incidence of the illumination from the sample surface;
a detector system configured to detect the reflected light at the dynamically varied angles of incidence of the illumination from a multiplicity of focal areas and to produce detection signals; and
a processing system comprising a hardware processor that is configured to process the detection signals from each module to measure parameters of the sample surface,
wherein each focal area of the sample surface that is illuminated by the first optical system is separated on the sample surface.
16. The system of claim 15 , wherein each module includes a laser source along with collimation and polarization optics.
17. The system of claim 15 , wherein a single laser source, collimation optics, polarization optics and beam-splitting optics are provided to deliver a collimated polarized laser beam to each module.