Alignment-marker structure and method of forming the same in integrated circuit fabrication
US6060786A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 17, 1999 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | May 17, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An alignment-marker structure and a method of forming the same in IC fabrication are provided. The alignment-marker structure is used for the purpose of assisting the precise alignment of a photomask used in photolithography on a wafer. In the fabrication process, a semiconductor substrate is prepared and then formed with a trench at a predefined location. A first conformal metallization layer is then formed over the substrate to a controlled thickness. Next, a sidewall-spacer structure is formed on the sidewall of the recessed portion of the first metallization layer. After this, a chemical-mechanical polishing (CMP) process is performed to polish away all the portions of the first metallization layer and the sidewall-spacer structure that lie over the top surface of the substrate. Finally, a second conformal metallization layer is formed over the substrate. Due to the conformal formation, the second metallization layer is formed with a recessed portion serving as the intended alignment mark. By the foregoing method, the resulting alignment-marker structure is more distinguishable than the prior art, allowing the mask alignment to be more precise.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.