Backside image sensor pixel with silicon microlenses and metal reflector
US8716823B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 25, 2012 |
| Grant date | May 6, 2014 |
| Priority date | — |
| Expiry date | May 25, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/811
Abstract
A backside illumination (BSI) image sensor pixel that includes microlenses with elevated refractive indices is provided. The image sensor pixel may include a photodiode formed in a silicon substrate, a first microlens formed in a back surface of the substrate, a second microlens formed over a front surface of the substrate, a dielectric stack formed on the front surface of the substrate, and a reflective structure formed in the dielectric stack above the second microlens. The first microlens may be fabricated by forming shallow trench isolation structures in the back surface. The second microlens may be fabricated by depositing polysilicon on the front substrate of the substrate. The first microlens may serve to concentrate light towards the photodiode, whereas the second microlens may serve to collimate light that traverses through the substrate so that light exiting the second microlens will reflect off the reflective structure and back into the photodiode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.