Kla Tencor Corporation

Kla-tencor Technologies Corporation

Alexander Slobodov

Anatoly Romanovsky

Christian Wolters

Zhongping Cai

Yury Yuditsky

Paul Doyle

Tyler Trytko

Jingyi Xiong

Yunxian Chu

A system for substrate tilt and focus control in an inspection system includes a dynamically actuatable substrate stage assembly including a substrate stage for securing a substrate; a tilt-height detection system including: a height detection sub-system and a tilt detection sub-system. The system further includes a first actuator configured to selectably actuate the substrate along a direction perpendicular to the surface of the substrate at a location of the substrate stage assembly; and an additional actuator configured to selectably actuate the substrate along a direction substantially perpendicular to the surface of the substrate at an additional location of the substrate stage assembly; and a MIMO tilt-focus controller communicatively coupled to the height detection sub-system, the tilt detection sub-system, the first actuator and the additional actuator.

Method and system for simultaneous tilt and height control of a substrate surface in an inspection system

A wafer is moved under an inspection spot by a rotary inspection system. The system rotates the wafer about an axis of rotation and translates the wafer along a linear trajectory. When the inspection spot is not aligned with the trajectory of the axis of rotation, an angular error is introduced in the representation of the position of the inspection spot with respect to the wafer by the rotary encoder. The angular error is corrected based on an angular error correction value. The angular error correction value is determined based on the distance between the inspection spot and the trajectory of the axis of rotation, the radial distance between the axis of rotation and the inspection spot at a first instance of a particular angular position, and a second radial distance between the axis of rotation and the inspection location at a second instance of the angular position.

Scanning inspection system with angular correction

Various embodiments for extended defect sizing range for wafer inspection are provided. One inspection system includes an illumination subsystem configured to direct light to the wafer. The system also includes an image sensor configured to detect light scattered from wafer defects and to generate output responsive to the scattered light. The image sensor is also configured to not have an anti-blooming feature such that when a pixel in the image sensor reaches full well capacity, excess charge flows from the pixel to one or more neighboring pixels in the image sensor. The system further includes a computer subsystem configured to detect the defects on the wafer using the output and to determine a size of the defects on the wafer using the output generated by a pixel and any neighboring pixels of the pixel to which the excess charge flows.

Extended defect sizing range for wafer inspection

An inspection system and method for serial high-speed image data transfer is provided herein. According to one embodiment, the method may include receiving multiple channels of image data at an input data rate and buffering the image data at the input data rate until the buffered data reaches a predetermined size. Once the predetermined size has been reached, the method may include packing the buffered data, encoding the data packet, serializing the encoded data packet and converting the encoded data packet into an optical signal. In some cases, the image data may be packed along with a data header containing information about the system. Once converted, each optical signal (i.e., representing one data packet) may be transmitted serially over one or more fibre channels to a processing node of the inspection system. In most cases, the data is packed, encoded, serialized and transmitted to the processing node at a data rate much higher than the input data rate. The processing node analyzes the optical signal to detect defects on a specimen under inspection.

Inspection system and method for high-speed serial data transfer

Inspection systems, circuits and methods are provided to enhance defect detection by addressing anode saturation as a limiting factor of the measurement detection range of a photomultiplier tube (PMT) detector. In accordance with one embodiment of the invention, a method for inspecting a specimen includes directing light to the specimen and detecting light scattered from the specimen. The step of detecting may include monitoring an anode current of the PMT detector, and detecting features, defects or light scattering properties of the specimen using the anode current until the anode current reaches a predetermined threshold. Thereafter, the method may use a dynode current of the PMT for detecting the features, defects or light scattering properties of the specimen.

Systems, circuits and methods for extending the detection range of an inspection system by avoiding detector saturation

An inspection system and method is provided herein for increasing the detection range of the inspection system. According to one embodiment, the inspection system may include a photodetector having a plurality of stages, which are adapted to convert light scattered from a specimen into an output signal, and a voltage divider network coupled for extending the detection range of the photodetector (and thus, the detection range of the inspection system) by saturating at least one of the stages. This forces the photodetector to operate in a non-linear manner. However, measurement inaccuracies are avoided by calibrating the photodetector output to remove any non-linear effects that may be created by intentionally saturating the at least one of the stages. In one example, a table of values may be generated during a calibration phase to convert the photodetector output into an actual amount of scattered light.

Inspection systems and methods for extending the detection range of an inspection system by forcing the photodetector into the non-linear range

Inspection systems, circuits and methods are provided to enhance defect detection by addressing saturation levels of the amplifier and analog-digital circuitry as a limiting factor of the measurement detection range of an inspection system. In accordance with one embodiment of the invention, a method for inspecting a specimen includes directing light to the specimen and detecting light scattered from the specimen. However, the step of detecting may use only one photodetector for detecting the light scattered from the specimen and for converting the light into an electrical signal. The step of detecting also includes generating a first signal and a second signal in response to the electrical signal, where the second signal differs from the first. For example, the first signal may be generated to have a higher resolution than the second signal for detecting substantially lower levels of the scattered light. In most cases, the method may use the first signal for detecting features, defects or light scattering properties of the specimen until the first signal reaches a predetermined threshold value. Once the predetermined threshold value is reached, however, the method may use the second signal for said detecting.

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San Jose, CA, United States of America

Alexander Slobodov