TSMC patent application US20110254115 "Inserted reflective shield to improve quantum efficiency of image sensors" joined a growing group of applications proposing to put a reflector in BSI pixel to increase its red and IR QE:
"Examples of reflective metals that can be used for such application include, but are not limited to, tungsten (W), aluminum (Al), and copper (Cu), zinc (Zn, gold (Au), silver (Ag), titanium (Ti), tantalum (Ta), chromium (Cr), tin (Sn), cobalt (Co), and nickel (Ni). The reflective material can also be a metal-containing film or an alloy that is made of two or more metals. Non-metal (or non-metallic) materials that are reflective may also be used. For example, polytetrafluorethylene (PTFE) is a polymer that has high reflectivity."
Is this even patentable?
ReplyDeleteIt seems obvious, as in an inevitable application of known principles.
All the nocturn aminals have patented this for long time .... :)
ReplyDeleteI have seen many applications similar to this one but who knows. It may be the exact details that count, not the general idea. I saw this first in an infrared PtSi CCD paper from Kosonocky a long time ago. (a mirror to reflect BSI for a 2nd pass)
ReplyDeleteHere are some patent documents that are relevant (all US).
ReplyDelete6255681
6498336
7755123
7888159
7982177
20070001100
20080099804
20090050947
20110140221