From Nikkei:  Sony Corp has developed a CMOS sensor using BSI (backside illumination) technology.  Now we have prospects for the volume production of the CMOS sensor," Sony said. "We will determine detailed specifications with candidate clients from now,"  Sony is the second company that ever announced a mass-produced application of BSI technology following OmniVision Technologies Inc of the US.  Sony is regarded as the 800 pound gorilla in the image sensor industry for digital cameras. OmniVision is, on the other hand, a fresh manufacturer of image sensors for mobile phones. Following these two companies' employment of BSI technology, technology development concerning BSI applications is likely to be focused by the image sensor and camera industry over the next few years. S/N ratio improvement of up to +8dB  Sony's announcement fell behind OmniVision's. However, Sony stressed that it has truly completed this technology by indicating specific figures concerning its features. The company is likely to start applying a BSI structure from a CMOS sensor for 5-Mpixel camcorders or digital cameras. Its pixel pitch is 1.75μm, and optical format is around 1/3.2 inch.  Compared with the announcement by OmniVision, Sony clearly highlighted the new sensor's superiority in signal-to-noise (S/N) ratio to its existing 1.75μm-pitch front-illuminated product. Specifically, the back-illuminated prototype features a signal sensitivity 6dB higher (combining the S and N values) when the lens aperture is F2.0.  Among noise (N) values, its random noise without light is 2dB lower. As a result, the CMOS sensor could achieve 8dB higher sensitivity (S/N ratio).  Sony has also disclosed the sensitivity variance based on the lens aperture. If the aperture is opened (the F value is lowered), the amount of light that enters the image sensor at an angle will increase.  Although it seems natural to consider boosting sensitivity (S/N ratio) making the most of light entering at an angle, it has been difficult to realize it with existing front-illuminated sensors. That is because, due to its angle, light does not efficiently reach the photoelectric converter (photo-diode) at the deep bottom of the CMOS sensor. The back-illuminated sensor has overcome this issue. As mentioned above, its signal sensitivity at F2.0 is 6dB higher than that achieved by front-illuminated sensors of the same pixel size. Its sensitivity is 4.5dB higher at F5.6, an F value that is relatively often used when assessing image quality. In addition to these figures, Sony and OmniVision announced the content of their prototypes as follows. Link