Apparatus and method for storing interferometric images of scanned defects and for subsequent static analysis of such defects

US5710631A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Akram Bou-Ghannam · Boynton Beach, US
• Alan Dorundo · Boca Raton, US
• Michael G. Lisanke · Boynton Beach, US
• Huizong Lu · Coral Springs, US
• Lanphuong Thi Pena · Jacksonville, US
• Ali Reza Taheri · Boca Raton, US
• Samuel So · San Jose, US
• Kenneth Wayne Watts · Boca Raton, US
• Darell Smith Whitaker · South Burlington, US

Key dates

• Filing date: Jan 27, 1997
• Grant date: Jan 20, 1998
• Expiry date: Jan 27, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N21/88
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An interferometer is used to locate and examine defects in a test surface of a test specimen. Defects are first located as the test surface is driven past the objective of the interferometer at a constant speed, with a darkfield interferogram being examined as it flows across a row of CCD elements. During this process, the location of each defect is stored. Next, the test specimen is sequentially moved into the locations at which static measurements are made using an area array of CCD elements. During these measurements, the phase angle relationship of the interferometer is varied so that heights of surface segments may be calculated. If some to these segments are located more than a quarter wave length of the interferometer light source from the surface at which the darkfield is established, a process is used to perform height corrections for segments within transition boundaries.