Method for improving the readability of alignment marks

US6153492A · kind A · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Stephan Wege · Osterburken, DE
• Peter Lahnor · Dresden, DE

Key dates

• Filing date: Jan 27, 2000
• Grant date: Nov 28, 2000
• Expiry date: Jan 27, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

The invention describes a method for improving the readability of alignment marks on semiconductor wafers during multilayer metallization. Metal located in the alignment marks is etched back for the purpose of uncovering the edges of the alignment marks after the deposition of metal and subsequent CMP step. In the alternative, the oxide in the immediate vicinity of the alignment marks is etched back in a recess etching step until the metal in the alignment mark is partly uncovered.