Local interconnect structure and method for a CMOS image sensor
AssigneeOmniVision Technologies, Inc.
InventorHoward Rhodes
Life of this patent
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Abstract
A self-aligned silicide (salicide) process is used to form a local interconnect for a CMOS image sensor consistent with a conventional CMOS image sensor process flow. An oxide layer is deposited over the pixel array of the image sensor. Portions of the oxide layer is removed and a metal layer is deposited. The metal layer is annealed to form a metal silicide. Optionally, a protective oxide layer is then deposited.
Claims41
An active pixel comprising:
- a photosensor formed in a semiconductor substrate;
- a transfer transistor formed between said photosensor and a floating node and selectively operative to transfer a signal from said photosensor to said floating node;
- an amplification transistor controlled by said floating node, said amplification transistor having an amplification gate;
- and
- a local interconnect structure electrically connecting said floating node to said amplification gate, said local interconnect structure formed on the sidewall of said amplification gate.
An active pixel comprising:
- a photosensor formed in a semiconductor substrate;
- a transfer transistor formed between said photosensor and a floating node and selectively operative to transfer a signal from said photosensor to said floating node;
- an amplification transistor controlled by said floating node, said amplification transistor having an amplification gate;
- and
- a local interconnect structure formed using a self-aligned silicide process to electrically connecting electrical regions of said pixel.
A method of forming a local interconnect structure for a pixel formed in a silicon substrate, said pixel having at least one gate structure, the method comprising:
- depositing an oxide layer over said pixel;
- removing portions of said oxide layer to expose said at least one gate structure and a portion of said silicon substrate;
- depositing a metal layer over said oxide layer, said at least one gate structure, and said portion of said semiconductor substrate;
- and
- forming a metal silicide by annealing said metal layer, said metal silicide being formed where said metal layer contacts said silicon substrate and said at least one gate structure;
- and
- leaving said metal layer on the sidewall of said at least one gate structure.
An active pixel comprising:
- a photosensor formed in a semiconductor substrate;
- an amplification transistor controlled by said photosensor, said amplification transistor having an amplification gate;
- and
- a local interconnect structure formed using a self-aligned silicide process to electrically connecting electrical regions of said pixel.
An image sensor structure comprising:
- a plurality of pixels each having at least:
- a photosensor formed in a semiconductor substrate;
- an amplification transistor controlled by said floating node, said amplification transistor having an amplification gate;
- and
- a local interconnect structure formed using a self-aligned silicide process to electrically connecting electrical regions between said plurality of pixels.
Dependencies are inferred from the claim text.