Methods for forming alignment marks

US11899376B1 · kind B1 · utility

Assignee

• Applied Materials, Inc. · US

Inventors

• Prayudi Lianto · Singapore, SG
• Liu Jiang · Clifton Park, US
• Marvin L. Bernt · Kalispell, US
• El Mehdi Bazizi · Saratoga Springs, US
• Guan Huei See · Singapore, SG

Key dates

• Filing date: Aug 31, 2022
• Grant date: Feb 13, 2024
• Expiry date: Oct 13, 2042

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2223/54486
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method for forming alignment marks leverages pad density and critical dimensions (CDs). In some embodiments, the method includes forming first and second alignment marks on a first substrate and a second substrate where the alignment marks have a width within 5% of the associated CD of copper pads on the respective substrates and forming a first and second dummy patterns around the first and second alignment marks. The first and second dummy patterns have dummy pattern densities within 5% of the respective copper pad density of the first and second substrates and CDs within 5% of the respective copper pad CDs. In some embodiments, alignment marks with physical dielectric material protrusions and recesses on opposite substrate surfaces may further enhance bonding.