Stacked-chip imaging systems
View Patent ↗Imaging systems may be provided with stacked-chip image sensors. A stacked-chip image sensor may include a vertical chip stack that includes an array of image pixels, analog control circuitry and storage and processing circuitry. The array of image pixels, the analog control circuitry, and the storage and processing circuitry may be formed on separate, stacked semiconductor substrates or may be formed in a vertical stack on a common semiconductor substrate. The image pixel array may be coupled to the control circuitry using vertical metal interconnects. The control circuitry may route pixel control signals and readout image data signals over the vertical metal interconnects. The control circuitry may provide digital image data to the storage and processing circuitry over additional vertical conductive interconnects coupled between the control circuitry and the storage and processing circuitry. The storage and processing circuitry may be configured to store and/or process the digital image data.
1. A stacked-chip image sensor, comprising:
a semiconductor substrate having opposing first and second surfaces;
an array of image sensor pixels in the semiconductor substrate that are configured to receive image light through the first surface; and
control circuitry coupled to the array of image sensor pixels by a plurality of vertical conductive interconnects that extend through the second surface, the array of image sensor pixels comprising image sensor pixels arranged in pixel rows and pixel columns, and the plurality of vertical conductive interconnects comprising a plurality of vertical column interconnects, wherein each pixel column is coupled to a selected one of the vertical column interconnects.
2. The stacked-chip image sensor defined in claim 1 , wherein the semiconductor substrate comprises a silicon semiconductor substrate and wherein the plurality of vertical conductive interconnects that extend through the second surface comprises a plurality of through-silicon vias that couple the control circuitry to the array of image sensor pixels through the second surface.
3. The stacked-chip image sensor defined in claim 1 wherein the plurality of vertical conductive interconnects that extend through the second surface comprises a two-dimensional array of microbumps that protrude from the second surface.
4. The stacked-chip image sensor defined in claim 1 wherein the control circuitry comprises row driver circuitry coupled to the vertical conductive interconnects and wherein the row driver circuitry is configured to supply pixel control signals to the image sensor pixels over the vertical conductive interconnects.
5. The stacked-chip image sensor defined in claim 4 wherein the plurality of vertical column interconnects are coupled to the pixel columns along an edge of the array of image sensor pixels and wherein the array of image sensor pixels comprises a plurality of pixel blocks, the stacked-chip image sensor further comprising:
a plurality of vertical internal row interconnects coupled to each of the pixel rows, wherein each of the plurality of vertical internal row interconnects is coupled a selected one of the pixel rows along an edge of an associated pixel block and wherein each of the plurality of vertical internal row interconnects couples image sensor pixels in the associated pixel block to the control circuitry through the second surface.
6. The stacked-chip image sensor defined in claim 1 , wherein the control circuitry comprises a plurality of analog to digital converter circuits and wherein each of the vertical column interconnects is coupled to a selected one of the analog to digital converter circuits.
7. The stacked-chip image sensor defined in claim 1 , wherein the semiconductor substrate is formed in a first semiconductor integrated circuit and the control circuitry is formed in a second semiconductor integrated circuit that is different from the first semiconductor integrated circuit.
8. A stacked-chip image sensor, comprising:
a semiconductor substrate having opposing first and second surfaces;
an array of image sensor pixels in the semiconductor substrate that are configured to receive image light through the first surface; and
control circuitry coupled to the array of image sensor pixels by a plurality of vertical conductive interconnects that extend through the second surface, wherein the array of image sensor pixels comprises a plurality of pixel blocks, the plurality of vertical conductive interconnects comprises a plurality of vertical block interconnects, and each of the plurality of vertical block interconnects couples the image sensor pixels of a respective one of the plurality of pixel blocks to the control circuitry through the second surface.
9. The stacked-chip image sensor defined in claim 8 , wherein the plurality of pixel blocks comprises a first pixel block and a second pixel block that is different from the first pixel block, a first vertical block interconnect of the plurality of vertical block interconnects couples the image sensor pixels of the first pixel block to the control circuitry through the second surface, and a second vertical block interconnect of the plurality of vertical block interconnects that is different from the first vertical block interconnect couples the image sensor pixels of the second pixel block to the control circuitry through the second surface.
10. The stacked-chip image sensor defined in claim 8 , wherein each pixel block of the plurality of pixel blocks includes a given number of image sensor pixels.
11. The stacked-chip image sensor defined in claim 8 , wherein each pixel block of the plurality of pixel blocks includes image sensor pixels from a first number of pixel columns and a second number of pixel rows, wherein the first number is greater than the second number.
12. The stacked-chip image sensor defined in claim 8 , wherein the semiconductor substrate is formed in a first semiconductor integrated circuit and the control circuitry is formed in a second semiconductor integrated circuit that is different from the first semiconductor integrated circuit.
13. The stacked-chip image sensor defined in claim 8 , wherein the control circuitry is configured to simultaneously select a plurality of rows of image sensor pixels in the array and to read out image data from a plurality of image sensor pixels in each of the simultaneously selected rows of image sensor pixels.
14. The stacked-chip image sensor defined in claim 8 wherein each of the image sensor pixels comprises a source follower transistor having a first terminal coupled to a selected one of the vertical block interconnects.
15. The stacked-chip image sensor defined in claim 8 wherein the control circuitry comprises a ground plane in a semiconductor integrated circuit die and an additional ground plane in the semiconductor integrated circuit die.
16. An image sensor, comprising:
a first integrated circuit die having opposing first and second surfaces and an array of image sensor pixels, wherein the array of image sensor pixels comprises pixel blocks;
a second integrated circuit die coupled to the first surface of the first integrated circuit die, wherein the second integrated circuit die includes control circuitry for operating the image sensor pixels to capture image data; and
vertical conductive interconnects coupled between the control circuitry and the array through the first surface of the first integrated circuit die, wherein each of the vertical conductive interconnects is coupled to a corresponding one of the pixel blocks.
17. The image sensor defined in claim 16 , wherein the control circuit is configured to provide control signals for capturing the image data to the pixel blocks over the vertical conductive interconnects.
18. The image sensor defined in claim 16 , wherein the control circuit is configured to receive the image data from the pixel blocks over the vertical conductive interconnects.
19. The image sensor defined in claim 16 , wherein the control circuitry comprises a plurality of analog-to-digital conversion circuits and wherein each of the analog-to-digital conversion circuits is coupled to a selected one of the vertical conductive interconnects.
20. The image sensor defined in claim 16 , wherein the image sensor pixels are configured to generate the image data in response to light received through the second surface.