Apparatus and methods for detecting overlay errors using scatterometry
US7616313B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 2006 |
| Grant date | Nov 10, 2009 |
| Priority date | — |
| Expiry date | Sep 21, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70633
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Embodiments of the invention include a scatterometry target for use in determining the alignment between substrate layers. A target arrangement is formed on a substrate and comprises a plurality of target cells. Each cell has two layers of periodic features constructed such that an upper layer is arranged above a lower layer and configured so that the periodic features of the upper layer have an offset and/or different pitch than periodic features of the lower layer. The pitches are arranged to generate a periodic signal when the target is exposed to an illumination source. The target also includes disambiguation features arranged between the cells and configured to resolve ambiguities caused by the periodic signals generated by the cells when exposed to the illumination source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.