Kla-Tencor Technologies Corporation

Kla Tencor Corporation

Shiow-Hwei Hwang

Tao-Yi Fu

Nat Ceglio

Gregory Kirk

Paul Frank Marella

Steve R Lange

Xiumei Liu

David R Shafer

Hwan J Jeong

Isabella Talley Lewis

Matthew Derstine

Grace Hsiu-Ling Chen

Richard William Solarz

Daniel L Cavan

Russel Hudyma

Stephane P Durant

Amir Bar

Gregory L Kirk

The present disclosure is directed to a system for inspecting a sample with multiple wavelengths of illumination simultaneously via parallel imaging paths. The system may include at least a first detector or set of detectors configured to detect illumination reflected, scattered, or radiated along a first imaging path from a selected portion of the sample in response to the first wavelength of illumination and a second detector or set of detectors configured to concurrently detect illumination reflected, scattered, or radiated along a second imaging path from the selected portion of the sample (i.e. the same location on the sample) in response to the second wavelength of illumination, where the second imaging path may at least partially share illumination and/or detection optics with an autofocus channel.

Inspection system including parallel imaging paths with multiple and selectable spectral bands

An optical system may include an objective having at least four mirrors including an outermost mirror with aspect ratio &#x3c;20:1 and focusing optics including a refractive optical element. The objective provides imaging at numerical aperture &#x3e;0.7, central obscuration &#x3c;35% in pupil. An objective may have two or more mirrors, one with a refractive module that seals off an outermost mirror's central opening. A broad band imaging system may include one objective and two or more imaging paths that provide imaging at numerical aperture &#x3e;0.7 and field of view &#x3e;0.8 mm. An optical imaging system may comprise an objective and two or more imaging paths. The imaging paths may provide two or more simultaneous broadband images of a sample in two or more modes. The modes may have different illumination and/or collection pupil apertures or different pixel sizes at the sample.

Optical imaging system with catoptric objective; broadband objective with mirror; and refractive lenses and broadband optical imaging system having two or more imaging paths

A wafer inspection system includes a laser droplet plasma (LDP) light source that generates light with sufficient radiance to enable bright field inspection at wavelengths down to 40 nanometers. Light generated by the LDP source is directed to the wafer and light from the illuminated wafer is collected by a high NA objective with all reflective elements. A detector detects the collected light for further image processing. The LDP source includes a droplet generator that dispenses droplets of a feed material. An excitation light generated by a laser is focused on a droplet of the feed material. The interaction of the excitation light with the droplet generates a plasma that emits illumination light with a radiance of at least 10 W/mm-sr within a spectral range from 40 nanometers to 200 nanometers.

Optical imaging system with laser droplet plasma illuminator

Methods and systems for inspection of a specimen using different parameters are provided. One computer-implemented method includes determining optimal parameters for inspection based on selected defects. This method also includes setting parameters of an inspection system at the optimal parameters prior to inspection. Another method for inspecting a specimen includes illuminating the specimen with light having a wavelength below about 350 nm and with light having a wavelength above about 350 nm. The method also includes processing signals representative of light collected from the specimen to detect defects or process variations on the specimen. One system configured to inspect a specimen includes a first optical subsystem coupled to a broadband light source and a second optical subsystem coupled to a laser. The system also includes a third optical subsystem configured to couple light from the first and second optical subsystems to an objective, which focuses the light onto the specimen.

Methods and systems for inspection of a specimen using different inspection parameters

Systems configured to generate output corresponding to defects on a specimen and systems configured to generate phase information about defects on a specimen are provided. One system includes an optical subsystem that is configured to create interference between a test beam and a reference beam. The test beam and the reference beam are reflected from the specimen. The system also includes a detector that is configured to generate output representative of the interference between the test and reference beams. The interference increases contrast between the output corresponding to the defects and output corresponding to non-defective portions of the specimen.

Systems configured to generate output corresponding to defects on a specimen

An inspection system for creating images of a substrate. A light source directs an incident light onto the substrate, and a light source timing control controls a pulse timing of the incident light. A stage holds the substrate and moves the substrate under the incident light, so that the substrate reflects the incident light as a reflected light. A stage position sensor reports a position of the stage, and a stage position control controls the position of the stage. A time domain integration sensor receives the reflected light, and a time domain integration sensor timing control controls a line shift of the time domain integration sensor. A control system is in communication with the light source timing control, the stage position control, and the time delay integration sensor timing control, and sets the pulse timing of the incident light, the position of the stage, and the line shift of the time delay integration sensor, such that a single line of the time domain integration sensor integrates reflected light from more than one pulse of the incident light from the light source.

Image collection

A system and method for coherent optical inspection are described. In one embodiment, an illuminating beam illuminates a sample, such as a semiconductor wafer, to generate a reflected beam. A reference beam then interferes with the reflected beam to generate an interference pattern at a detector, which records the interference pattern. The interference pattern may then be compared with a comparison image to determine differences between the interference pattern and the comparison image. According to another aspect, the phase difference between the reference beam and the reflected beam may be adjusted to enhance signal contrast. Another embodiment provides for using differential interference techniques to suppress a regular pattern in the sample.

System and method for coherent optical inspection

A system and method are disclosed for performing bright field and dark field optical inspection. In one embodiment, a system is provided for performing bright field coherent detection by means of an interferometer and dark field detection of scattered light using a single apparatus. In other embodiments, the system is operable to perform dark field detection of scattered light as well as phase measuring through phase shifting or spatial fringe analysis techniques. In yet another embodiment, an additional light source is provided for generating an illumination beam directed obliquely at the substrate to permit capture and detection of scattered light in directions near a normal direction to a surface of the substrate, and in directions away from a normal direction to a surface.

System and method for performing bright field and dark field optical inspection

An integrated interferometric and intensity based microscopic inspection system inspects semiconductor samples. A switchable illumination module provides illumination switchable between interferometric inspection and intensity based microscopic inspection modes. Complex field information is generated from interference image signals received at a sensor. Intensity based signals are used to perform the microscopic inspection. The system includes at least one illumination source for generating an illumination beam and an integrated interferometric microscope module for splitting the illumination beam into a test beam directed to the semiconductor sample and a reference beam directed to a tilted reference mirror. The beams are combined to generate an interference image at an image sensor. The tilted reference mirror is tilted with respect to the reference beam that is incident on the mirror to thereby generate fringes in the interference image. The system also includes an image sensor for acquiring the interference image from the inteferometric microscope module and intensity signals from the microscopic inspection image.

Method and apparatus using microscopic and interferometric based detection

In one embodiment, the present invention provides an interferometric inspection system for inspecting semiconductor samples. The system includes at least one illumination source for generating an illumination beam and an interferometric microscope module for splitting the illumination beam into a test beam directed to the semiconductor sample and a reference beam directed to a tilted reference mirror. The beams are combined to generate an interference image at an image sensor. The tilted reference mirror is tilted at a non-normal angle with respect to the reference beam that is incident on the mirror to thereby generate fringes in the interference image. The system also includes an image sensor for acquiring the interference image from the interferometric microscope module and generates an inherence signal. The system further includes a processing module configured to generate complex field information corresponding to the sample from the interference image signal and an alignment module located in the optical path between the interferometric module and the image sensor. In another embodiment, the processing module is configured to generate complex field information from either spatial fringe analysis or temporal fringe analysis performed on the interference image signal.

Growing community of inventors

Livermore, CA, United States of America

Shiow-Hwei Hwang