Method and apparatus for measuring a structure on a substrate
US10788765B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 2018 |
| Grant date | Sep 29, 2020 |
| Priority date | — |
| Expiry date | Jan 10, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2210/56
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
As increasing numbers of layers, using increasing numbers of specific materials, are deposited on substrates, it becomes increasingly difficult to detect alignment marks accurately for, for example, applying a desired pattern onto a substrate using a lithographic apparatus, in part due to one or more of the materials used in one or more of the layers being wholly or partially opaque to the radiation used to detect alignment marks. In a first step, the substrate is illuminated with excitation radiation. In a second step, at least one effect associated with a reflected material effect scattered by a buried structure is measured. The effect may, for example, include a physical displacement of the surface of the substrate. In a third step, at least one characteristic of the structure based on the measured effect is derived.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.