Patent ID: 9478579
Filing Date: 2016-10-25
CPC Classification: H01L

Claim Text:
1. An imaging sensor system, comprising: a first semiconductor layer of a first wafer; a complementary metal oxide semiconductor (CMOS) imaging array formed in the first semiconductor layer, wherein the CMOS imaging array includes an N number of pixels, each pixel including a photodiode region formed in a front side of the first semiconductor layer, and wherein the photodiode region is configured to received light from a backside of the first semiconductor layer; a first metal stack disposed on the front side of the first semiconductor layer; a second semiconductor layer of a second wafer; a second metal stack disposed on the second semiconductor layer, wherein the first wafer is bonded to the second wafer at a bonding interface between the first metal stack and the second metal stack; and a storage device formed directly below the CMOS imaging array in the second semiconductor layer and electrically coupled to the CMOS imaging array by way of the first and second metal stacks, wherein the storage device includes at least N number of storage cells, wherein each of the N number of storage cells are configured to store a signal representative of image charge accumulated by a respective photodiode region and wherein each of the N number of storage cells includes a light-sensitive circuit element that is sensitive to light-induced leakage; wherein the CMOS imaging array, the first metal stack, and the second metal stack are configured to prevent substantially all light from reaching the light-sensitive circuit elements.