Method for performing an alignment measurement of two patterns in different layers on a semiconductor wafer

US6908775B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Rolf Heine · Rinteln, DE
• Sebastian Schmidt · Weisendorf, DE
• Thorsten Schedel · Dresden, DE

Key dates

• Filing date: Nov 14, 2003
• Grant date: Jun 21, 2005
• Expiry date: Nov 14, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G06T2207/30148
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

In an alignment or overlay measurement of patterns on a semiconductor wafer an error that occurs during the measurement in one of a predefined number of alignment structures in an exposure field of a corresponding predefined set of exposure fields can be handled by selecting an alignment structure in a substitute exposure field. The latter exposure field need not be part of the predefined set of exposure fields, that is, an inter-field change may be effected. The number of alignment measurements on a wafer remains constant and the quality is increased. Alternatively, when using another alignment structure in the same exposure field—by effecting an intra-field change—the method becomes particularly advantageous when different minimum structure sizes are considered for the substitute targets. Due to the different selectivity in, say, a previous CMP process, such targets might not erode and do not cause an error in a measurement, thus providing an increased alignment or overlay quality.