Littrow gratings as alignment structures for the wafer level testing of optical and optoelectronic chips
US7024066B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 2004 |
| Grant date | Apr 4, 2006 |
| Priority date | — |
| Expiry date | Dec 17, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/122
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This application describes, among others, wafer designs, testing systems and techniques for wafer-level optical and optoelectronic testing by coupling probe light to/from the top of the wafer. In the described exemplary implementations, wafers are designed with one or more optical alignment features or structures. The alignment structures are alongside the devices to be tested, but are easier to find or locate by optical means, than the devices to be tested. An optical diffraction grating structure such as a Littrow grating may be used as reflective alignment structures. (FIG. 6B and paragraph 56.) A Littrow grating as an alignment structure produces a retro-reflection. A Littrow grating is a one-port optical device, with input and output beams going along the same path. Various exemplary implementations are shown in FIGS. 3C, 5, 6A, 6B, 7A and 7B and described in paragraphs 18–21, 39–40 and 53–64.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.