Backside illuminated image sensor pixels with dark field microlenses
US8890221B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 2013 |
| Grant date | Nov 18, 2014 |
| Priority date | — |
| Expiry date | Sep 19, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/8057
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A backside illuminated image sensor with an array of image sensor pixels is provided. Each image pixel may include a photodiode and associated pixel circuits formed in a front surface of a semiconductor substrate. Silicon inner microlenses may be formed on a back surface of the semiconductor substrate. In particular, positive inner microlenses may be formed over the photodiodes, whereas negative inner microlenses may be formed over the associated pixel circuits. Buried light shielding structures may be formed over the negative inner microlenses to prevent pixel circuitry that is formed in the substrate between two neighboring photodiodes from being exposed to incoming light. The buried light shielding structures may be lined with absorptive antireflective coating material to prevent light from being reflected off the surface of the buried light shielding structures. Forming buried light shielding structures with antireflective coating material can reduce optical pixel crosstalk and enhance global shutter efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.