Alignment mark structure and method of fabricating the same
US11145602B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 2020 |
| Grant date | Oct 12, 2021 |
| Priority date | — |
| Expiry date | Apr 24, 2040 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2223/5446
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An alignment mark structure includes a dielectric layer. A trench is embedded in the dielectric layer. An alignment mark fills up the trench, wherein the alignment mark includes a metal layer covering the trench. A first material layer covers and contacts the metal layer. A second material layer covers and contacts the first material layer. A third material layer covers and contacts the second material layer. The first material layer, the second material layer, and the third material layer independently includes silicon nitride, silicon oxide, tantalum-containing material, aluminum-containing material, titanium-containing material, or a low-k dielectric having a dielectric constant smaller than 2.7, and a reflectance of the first material layer is larger than a reflectance of the second material layer, the reflectance of the second material layer is larger than a reflectance of the third material layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.