公开(公告)号：US20240162074A1

公开(公告)日：2024-05-16

申请号：US18387015

申请日：2023-11-04

Applicant: KLA Corporation

Inventor： Phalguna Rachinayani ,  Shankar Krishnan ,  Elinore Esaghoulyan

IPC: H01L21/68 ,  H01L21/66 ,  H01L21/67

CPC classification number: H01L21/681 ,  H01L21/67259 ,  H01L21/67288 ,  H01L22/24

Abstract: Wafer tilt is measured and compensated based on corrected measurements of tilt derived from a set of height measurements across a wafer. A set of wafer orientation correction values is generated by a measurement system at a large number of wafer locations. At each location, a wafer orientation correction value is determined based on a difference between the local wafer tilt of a calibration wafer measured by an optical tilt sensor and a corresponding estimated value of the local slope of the calibration wafer derived from Z-measurements. The same measurement system performs Z-measurements of a sample wafer and estimates the local slope at each location. The difference between the corresponding wafer orientation correction value and the local slope at each location accurately estimates the wafer orientation at each measurement location. The wafer orientation is adjusted based on the corrected value of wafer orientation.

公开(公告)号：US11906770B2

公开(公告)日：2024-02-20

申请号：US17541037

申请日：2021-12-02

Applicant: KLA Corporation

Inventor： Shankar Krishnan ,  David Y. Wang

IPC: G02B5/30 ,  G02B5/04 ,  G01J3/02 ,  G01J3/14 ,  G02B17/04

CPC classification number: G02B5/3091 ,  G01J3/0224 ,  G01J3/14 ,  G02B5/04 ,  G02B17/04

Abstract: A monolithic optical retarder formed from a monolithic prism may include an input face for receiving a light beam, an output face aligned with an optical axis of the light beam prior to entering the input face, and three or more reflection faces. The three or more reflection faces may be oriented to provide an optical path for the light beam from the input face to the output face via reflection by the three or more reflection faces, where the monolithic optical retarder imparts a selected optical retardation on the light beam based on total internal reflection on at least one of the reflection faces. Further, the input face, the output face, and the three or more reflection faces may be oriented such that an optical axis of the light beam exiting the output face is equal to the optical axis of the light beam entering the input face.

公开(公告)号：US20240053280A1

公开(公告)日：2024-02-15

申请号：US18229606

申请日：2023-08-02

Applicant: KLA Corporation

Inventor： Ming Di ,  Yih-Chung Chang ,  Xi Chen ,  Dawei Hu ,  Ce Xu ,  Bowei Huang ,  Igor Baskin ,  Mark Allen Neil ,  Tianhao Zhang ,  Malik Karman Sadiq ,  Shankar Krishnan ,  Jenching Tsai ,  Carlos L. Ygartua ,  Yao-Chung Tsao ,  Qiang Zhao

IPC: G01N21/95 ,  H01L21/66

CPC classification number: G01N21/9501 ,  H01L22/12

Abstract: Methods and systems for compensating systematic errors across a fleet of metrology systems based on a trained error evaluation model to improve matching of measurement results across the fleet are described herein. In one aspect, the error evaluation model is a machine learning based model trained based on a set of composite measurement matching signals. Composite measurement matching signals are generated based on measurement signals generated by each target measurement system and corresponding model-based measurement signals associated with each target measurement system and reference measurement system. The training data set also includes an indication of whether each target system is operating within specification, an indication of the values of system model parameter of each target system, or both. In some embodiments, the composite measurement matching signals driving the training of the error evaluation model are weighted differently, for example, based on measurement sensitivity, measurement noise, or both.

公开(公告)号：US20230341337A1

公开(公告)日：2023-10-26

申请号：US18185100

申请日：2023-03-16

Applicant: KLA Corporation

Inventor： David Y. Wang ,  Shankar Krishnan

IPC: G01N21/95

CPC classification number: G01N21/9501 ,  G01N2021/9511

Abstract: The system includes a light source configured to emit light along an illumination path; a projection optical assembly disposed in the illumination path; a target disposed in the illumination path and configured to reflect the light along a collection path; a collection optical assembly disposed in the collection path; a detector disposed in the collection path and configured to detect the light reflected from the target and generate an output signal based on the detected light; and a processor in electronic communication with the detector and configured to generate a measurement of the target based on the output signal. The projection optical assembly defines a first numerical aperture at the target and the collection optical assembly defines a second numerical aperture at the target, and the first numerical aperture is slightly larger than the second numerical aperture for measurements of thick films and high aspect ratio structures.