Methods and apparatus for alignment marks
US9899334B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 2016 |
| Grant date | Feb 20, 2018 |
| Priority date | — |
| Expiry date | Dec 27, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2223/5446
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method includes: growing a oxide layer on a topside of a semiconductor wafer using a local oxidation of silicon (LOCOS) process; forming a photoresist pattern with an alignment opening on the oxide layer; etching the oxide layer to form a trench in the oxide layer; etching an alignment mark trench into the exposed surface of the semiconductor wafer; depositing a dielectric layer that is one of a silicon nitride material or a silicon oxynitride material; performing an anisotropic plasma etch to remove the dielectric layer from horizontal surfaces on the oxide layer and the alignment mark trench and to form sidewalls from the dielectric layer on vertical sidewalls of the alignment mark trench; growing an alignment mark oxide layer on a bottom surface of the alignment trench; and etching and removing the oxide layer and the alignment mark oxide layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.