SOLID-STATE IMAGING DEVICE, METHOD FOR MANUFACTURING THE SAME, AND ELECTRONIC APPARATUS

• US 20130001730A1
• Filed: 06/20/2012
• Published: 01/03/2013
• Est. Priority Date: 06/28/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Miyanami, Yuki
• Granted Patent: US 9,202,839 B2
• Time in Patent Office: Days
• US Class Current: 257/443
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H01L 27/14687 Wafer level processing
• CPC Class Codes: H01L 27/14689 MOS based technologies

Abstract

A solid-state imaging device includes a semiconductor substrate, a connection portion, and one or more first photoelectric conversion units formed in the semiconductor substrate. The semiconductor substrate has a back side and a front side. The back side is a light incident surface, and the front side is a circuit-forming surface. The connection portion is connected to a contact plug that transfers signal charges generated on the back side of the semiconductor substrate into the semiconductor substrate. The connection portion has a peak of an impurity concentration distribution near an interface of the semiconductor substrate on the back side of the semiconductor substrate.

Claims

1. A solid-state imaging device comprising:

a semiconductor substrate having a back side and a front side, the back side being a light incident surface, the front side being a circuit-forming surface;

a connection portion connected to a contact plug that transfers signal charges generated on the back side of the semiconductor substrate into the semiconductor substrate, the connection portion having a peak of an impurity concentration distribution near an interface of the semiconductor substrate on the back side of the semiconductor substrate; and

one or more first photoelectric conversion units formed in the semiconductor substrate.

2. The solid-state imaging device according to claim 1, further comprising:

a second photoelectric conversion unit for a first color stacked on the semiconductor substrate on the light incident surface side of the semiconductor substrate, the second photoelectric conversion unit being sandwiched between a lower electrode and an upper electrode,

wherein the one or more first photoelectric conversion units include a photoelectric conversion unit for a second color and a photoelectric conversion unit for a third color, the photoelectric conversion unit for the second color and the photoelectric conversion unit for the third color being stacked on top of one another in a depth direction of the semiconductor substrate, and

wherein the signal charges are generated in the second photoelectric conversion unit for the first color, and are supplied to the connection portion.

3. The solid-state imaging device according to claim 1, wherein

the connection portion is formed by selectively etching a first region of a semiconductor layer having a first thickness to a second thickness and then ion-implanting impurities into the first region, and

after ion implantation, the first region etched to the second thickness is backfilled to the first thickness by epitaxial growth, and then epitaxial growth is performed to increase the thickness of the semiconductor layer having the first thickness to a third thickness to obtain the semiconductor substrate.

4. The solid-state imaging device according to claim 3, wherein

after the first region is backfilled to the first thickness by epitaxial growth, one of the first photoelectric conversion units is formed in a second region at a horizontal position different from a horizontal position of the connection portion in the semiconductor layer having the first thickness.

5. The solid-state imaging device according to claim 1, wherein

the connection portion is formed by ion-implanting impurities into a first region of a semiconductor layer having a first thickness,

after ion implantation, epitaxial growth is performed to increase the thickness of the semiconductor layer having the first thickness to a second thickness, and

epitaxial growth is further performed to increase the thickness of the semiconductor layer having the second thickness to a third thickness to obtain the semiconductor substrate.

6. The solid-state imaging device according to claim 5, wherein

after epitaxial growth is performed to increase the thickness of the semiconductor layer to the second thickness, one of the first photoelectric conversion units is formed in a second region at a horizontal position different from a horizontal position of the connection portion in the semiconductor layer having the second thickness.

7. The solid-state imaging device according to claim 1, wherein

the peak of the impurity concentration distribution is within 100 nm from the interface of the semiconductor substrate on the back side of the semiconductor substrate.

8. A method for manufacturing a solid-state imaging device, comprising:

forming a connection portion by ion-implanting impurities into a first region of a semiconductor substrate having a first thickness, the connection portion being connected to a contact plug that transfers signal charges generated on a back side of the semiconductor substrate into the semiconductor substrate, the back side of the semiconductor substrate being a light incident surface, the connection portion having a peak of an impurity concentration distribution near an interface of the semiconductor substrate on the back side of the semiconductor substrate;

performing epitaxial growth to increase the thickness of the semiconductor substrate having the first thickness to a second thickness;

forming a first photoelectric conversion layer in a second region at a horizontal position different from a horizontal position of the connection portion in the semiconductor substrate having the second thickness, the first photoelectric conversion layer being configured to photoelectrically convert light having a first wavelength; and

further performing epitaxial growth to increase the thickness of the semiconductor substrate having the second thickness to a third thickness.

9. The method according to claim 8, wherein

the forming of the connection portion includes forming the connection portion by ion-implanting impurities into the first region of the semiconductor substrate, the first region being selectively etched from a fourth thickness larger than the first thickness so as to have the first thickness, and

the performing of epitaxial growth includes performing epitaxial growth, after ion implantation, to backfill the etched first region by a thickness equal to the first thickness to increase the thickness of the first region to the second thickness.

10. The method according to claim 8, further comprising:

forming a second photoelectric conversion layer at a position in a depth direction that is more distant from the back side of the semiconductor substrate having the third thickness than the first photoelectric conversion layer, the second photoelectric conversion layer being configured to photoelectrically convert light having a second wavelength.

11. An electronic apparatus comprising:

a solid-state imaging device that light collected by an optical lens enters; and

a signal processing circuit configured to process an output signal of the solid-state imaging device,

the solid-state imaging device including

a semiconductor substrate having a back side and a front side, the back side being a light incident surface, the front side being a circuit-forming surface,

a connection portion connected to a contact plug that transfers signal charges generated on the back side of the semiconductor substrate into the semiconductor substrate, the connection portion having a peak of an impurity concentration distribution near an interface of the semiconductor substrate on the back side of the semiconductor substrate, and

one or more first photoelectric conversion units formed in the semiconductor substrate.