Nicholas J Keller

US Patent:

20220357286, Nov 10, 2022

Filed:

May 5, 2021

Appl. No.:

17/308949

Inventors:

- Wilmington MA, US
Nicholas James KELLER - La Jolla CA, US

International Classification:

G01N 21/956
G01N 21/95
G06F 30/3308
G01N 21/21
G06F 30/347

Abstract:

Characteristics of a standard logic cell, e.g., a random logic cell, are determined using an effective cell approximation. The effective cell approximation is smaller than the standard logic cell and represents the density of lines and spaces of the standard logic cell. The effective cell approximation may be produced based on a selected area from the standard logic cell and include the same non-periodic patterns as the selected area. The effective cell approximation, alternatively, may represent non-periodic patterns in the standard logic cell using periodic patterns having a same density of lines and spaces as found in the standard logic cell. A structure on the sample, such as a logic cell or a metrology target produced based on the effective cell approximation is measured to acquire data, which is compared to the data for the effective cell approximation to determine a characteristic of the standard logic cell.

US Patent:

20220326626, Oct 13, 2022

Filed:

Mar 29, 2022

Appl. No.:

17/707776

Inventors:

- Wilmington MA, US
Francis Scott HOOVER - Houston TX, US
Nicholas James KELLER - La Jolla CA, US
Kevin Eduard Heidrich - Beaverton OR, US

International Classification:

G03F 7/20
G01B 11/27
G03F 1/70

Abstract:

Overlay is determined for a device using signals measured from the device and a signal response to overlay determined from a plurality of calibration targets. Each calibration target has the same design as the device, but includes a known overlay shift. The calibration targets may be located in a scribe line, within a product area on the wafer, or on a separate calibration wafer. Each calibration target may have a different overlay shift, including zero overlay shift. The device may serve as a calibration target with zero overlay shift. The overlay shift may be in two orthogonal directions. The signal response to overlay may be determined based on a set of signals obtained from the calibration targets. A second set of signals may then be obtained from the device and the overlay determined based on the second set of signals and the determined signal response to overlay.

US Patent:

20220317025, Oct 6, 2022

Filed:

Mar 30, 2021

Appl. No.:

17/217990

Inventors:

- Wilmington MA, US
Manjusha S. Mehendale - Morristown NJ, US
Robin Mair - West Chicago IL, US
Nicholas James Keller - La Jolla CA, US

International Classification:

G01N 21/17
G01B 11/22
G01B 11/06

Abstract:

A non-destructive opto-acoustic metrology device detects the presence and location of non-uniformities in a film stack that includes a large number, e.g., 50 or more, transparent layers. A transducer layer at the bottom of the film stack produces an acoustic wave in response to an excitation beam. A probe beam is reflected from the layer interfaces of the film stack and the acoustic wave to produce an interference signal that encodes data in a time domain from destructive and constructive interference as the acoustic wave propagates upward in the film stack. The data may be analyzed across the time domain to determine the presence and location of one or more non-uniformities in the film stack. An acoustic metrology target may be produced with a transducer layer configured to generate an acoustic wave with a desired acoustic profile based on characteristics of the film stack.