Multi-scanning electron microscopy for wafer alignment

US10901391B1 · kind B1 · utility

Assignee

• Carl Zeiss SMT GmbH · DE

Inventors

• Jagdish Chandra Saraswatula · Chennai, IN
• Jens Timo Neumann · Shanghai, CN
• Philipp Huethwohl · Ulm, DE
• Thomas Korb · Schwäbisch Gmünd, DE
• Raghavendra Hanumantha Nayak · Pleasanton, US

Key dates

• Filing date: Sep 9, 2019
• Grant date: Jan 26, 2021
• Expiry date: Sep 9, 2039

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P90/02
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method includes controlling a multi-scanning electron microscope, mSEM, to capture a first image of a wafer attached to a motorized handling stage while the motorized handling stage is in a first position. The first image includes at least a part of a notch of the wafer. The method also includes determining a radial axis of the wafer based on the first image, and controlling the motorized handling stage to shift the wafer along the radial axis by half a diameter of the wafer so that the motorized handling stage is in a second position. The method further includes controlling the mSEM to capture a second image of the wafer while the motorized handling stage is in the second position. The second image includes wafer structures. In addition, the method includes determining a reference position of the wafer based on a structure recognition of the wafer structures of the second image, and registering a wafer coordinate system of the wafer to a stage coordinate system of the motorized handling stage based on the reference position and the radial axis.