Canon applies for a BSI stacked sensor patent

This patent is highly detailed and very specific.  It's really difficult to imagine that we're not going to see this technology in Canon cameras sooner than later.

This patent is about offloading heat generated from the processing substrate.  Heat of any sort is bad for an image sensor, as that turns into noise.  As you move more processing into the image sensor substrates you increase the heat generated.

This is the most detailed stacked sensor patent application that I've seen to date, and it gets really specific on the size, depth and measurements of the indidvidual sections of the sensor stack.   It also demonstrates in it's embodiments a back side illuminated sensor as the photoelectrical substrate.

The optical control film 40 containing the antireflection layer 61, the cladding layer 62, the light shielding layer 63, the core layer 69, the flattening layer 71, the color filter array 73, and the microlens array 74 is provided at the back surface 104 side of the 1st semiconductor substrate 10.

The patent application then goes on to detail versus heat sinking methods proposed to move off heat from the backside of the stacked sensor (including fan or direct air cooling as shown by b-1)

Of course, with all patent applications, this may never become an actual patent - however Canon is putting a lot of effort to solve problems with stacked sensors.  More than what they would if it was simply cursory in nature.

Japan Patent Application 2018-014519