CN-112992942-B - Image sensor

Abstract

An image sensor includes a semiconductor substrate having a first surface and a second surface and having a pixel region having a photoelectric conversion region, a gate electrode disposed on the pixel region and adjacent to the first surface, a first isolation structure extending from the first surface toward the second surface, the first isolation structure including a first pixel isolation pattern surrounding the pixel region, and a first internal isolation pattern spaced apart from the first pixel isolation pattern and located between the photoelectric conversion region, and a second isolation structure extending from the second surface toward the first surface and having a top surface vertically spaced apart from at least a portion of a bottom surface of the first isolation structure. The bottom surface of the first isolation structure is closer to the second surface of the semiconductor substrate than the first surface of the semiconductor substrate.

Inventors

• LI JINGGAO
• JIN FANXI
• SHEN YINXIE

Assignees

• 三星电子株式会社

Dates

Publication Date

20260508

Application Date

20201028

Priority Date

20191213

Claims (19)

1. 1. An image sensor, comprising: a semiconductor substrate having a first surface and a second surface, the semiconductor substrate including a pixel region having a plurality of photoelectric conversion regions; a gate electrode disposed on the pixel region and adjacent to the first surface; A first isolation structure extending from the first surface toward the second surface, the first isolation structure including a first pixel isolation pattern surrounding the pixel region, and a first internal isolation pattern spaced apart from the first pixel isolation pattern and located between the plurality of photoelectric conversion regions, and A second isolation structure extending from the second surface toward the first surface, the second isolation structure having a top surface vertically spaced apart from at least a portion of a bottom surface of the first isolation structure, Wherein the bottom surface of the first isolation structure is closer to the second surface of the semiconductor substrate than the first surface of the semiconductor substrate, Wherein, the image sensor further includes: A barrier region provided in the semiconductor substrate to cover a side surface of the first isolation structure, Wherein the photoelectric conversion region includes an impurity of a second conductivity type, and Wherein the barrier region and the semiconductor substrate include an impurity of a first conductivity type different from the second conductivity type, and a first concentration of the impurity of the first conductivity type of the barrier region is higher than a second concentration of the impurity of the first conductivity type of the semiconductor substrate.
2. 2. The image sensor of claim 1, Wherein the pixel region includes a connection region disposed between the first pixel isolation pattern and the first internal isolation pattern to connect two adjacent photoelectric conversion regions of the plurality of photoelectric conversion regions, and Wherein the connection region includes an impurity having the same second conductivity type as the impurity of the photoelectric conversion region.
3. 3. The image sensor of claim 2, Wherein the connection region is located at a vertical level between a top surface and a bottom surface of the first internal isolation pattern.
4. 4. The image sensor of claim 2, Wherein the connection region vertically overlaps the second isolation structure.
5. 5. The image sensor of claim 1, Wherein the first pixel isolation pattern and the second isolation structure are vertically spaced apart from each other.
6. 6. The image sensor of claim 1, Wherein the pixel region of the semiconductor substrate includes a first impurity of a first conductivity type, Wherein the photoelectric conversion region includes a second impurity of a second conductivity type different from the first conductivity type, and Wherein a concentration of the first impurity in the pixel region is higher than a concentration of the second impurity when measured at the same vertical level from the second surface toward the first surface of the semiconductor substrate.
7. 7. The image sensor of claim 1, Wherein the first isolation structure includes a first gap-fill pattern and a second gap-fill pattern disposed between the first gap-fill pattern and the semiconductor substrate, and Wherein the refractive index of the first gap-filling pattern is different from the refractive index of the second gap-filling pattern.
8. 8. The image sensor of claim 1, Wherein the second isolation structure includes a second pixel isolation pattern surrounding the pixel region and a second internal isolation pattern connected to the second pixel isolation pattern and located in the pixel region.
9. 9. The image sensor of claim 8, Wherein the second internal isolation pattern includes a first pattern extending parallel to the second surface and a second pattern disposed to intersect the first pattern.
10. 10. The image sensor of claim 1, Wherein the width of the first isolation structure decreases in a direction toward the second surface, and Wherein the width of the second isolation structure decreases in a direction toward the first surface.
11. 11. The image sensor of claim 1, further comprising: A readout circuit layer disposed on the first surface and including a connection line electrically connected to the gate electrode, and A microlens on the second surface.
12. 12. An image sensor, comprising: A semiconductor substrate including impurities of a first conductivity type, The semiconductor substrate has a first surface and a second surface opposite to each other, and includes a plurality of pixel regions; A first pixel isolation pattern provided in the semiconductor substrate to electrically isolate a first pixel region, which is one of the plurality of pixel regions, from other pixel regions of the plurality of pixel regions; A first photoelectric conversion region and a second photoelectric conversion region disposed in the first pixel region and including an impurity of a second conductivity type different from the first conductivity type; a first internal isolation pattern disposed between the first and second photoelectric conversion regions and spaced apart from the first pixel isolation pattern; A connection region disposed between the first pixel isolation pattern and the first internal isolation pattern to connect the first and second photoelectric conversion regions to each other, the connection region including an impurity of the second conductivity type, and A second internal isolation pattern disposed in the first pixel region and extending from the second surface toward the connection region and vertically spaced apart from the first surface, Wherein, the image sensor further includes: A barrier region provided in the semiconductor substrate to cover side surfaces of the first internal isolation pattern and the first pixel isolation pattern, Wherein the barrier region includes an impurity having the first conductivity type, and a first concentration of the impurity of the first conductivity type of the barrier region is higher than a second concentration of the impurity of the first conductivity type of the semiconductor substrate.
13. 13. The image sensor of claim 12, Wherein the impurity of the second conductivity type in the connection region and the impurity of the second conductivity type in the second photoelectric conversion region have the same concentration at the same vertical level.
14. 14. The image sensor of claim 12, Wherein a top surface of the second internal isolation pattern is closer to the first surface than the second surface.
15. 15. The image sensor of claim 12, further comprising: A gate electrode disposed adjacent to the first surface, Wherein the connection region is closer to the first surface than the second surface.
16. 16. An image sensor, comprising: A semiconductor substrate including an impurity of a first conductivity type, the semiconductor substrate including a pixel region and having a first surface and a second surface, the second surface and the first surface being opposite to each other in a vertical direction; a plurality of photoelectric conversion regions disposed in the pixel region and including impurities of a second conductivity type different from the first conductivity type; a gate electrode disposed on the photoelectric conversion region and adjacent to the first surface; A first isolation structure extending from the first surface toward the second surface, the first isolation structure including a first pixel isolation pattern surrounding the pixel region, and a first internal isolation pattern spaced apart from the first pixel isolation pattern and located between two adjacent photoelectric conversion regions of the plurality of photoelectric conversion regions; A second isolation structure extending from the second surface toward the first surface, the second isolation structure including a second pixel isolation pattern surrounding the pixel region, and a second internal isolation pattern connected to the second pixel isolation pattern and located in the pixel region; A barrier region disposed in the semiconductor substrate to cover the side surface of the first isolation structure and including the impurity of the first conductivity type, and A connection region including an impurity of the second conductivity type, the connection region being disposed between the first pixel isolation pattern and the first internal isolation pattern to connect two adjacent photoelectric conversion regions among the plurality of photoelectric conversion regions, Wherein a first concentration of the first conductivity type impurity of the barrier region is higher than a second concentration of the first conductivity type impurity of the semiconductor substrate.
17. 17. The image sensor of claim 16, Wherein a length of the second internal isolation pattern in the vertical direction is different from a length of the second pixel isolation pattern in the vertical direction.
18. 18. The image sensor of claim 16, Wherein the first pixel isolation pattern and the second isolation structure are vertically spaced apart from each other.
19. 19. The image sensor of claim 16, Wherein the length of the first pixel isolation pattern in the vertical direction is greater than the length of the second pixel isolation pattern in the vertical direction.

Description

Image sensor Cross Reference to Related Applications The present patent application claims priority from korean patent application No.10-2019-0167053, filed on the korean intellectual property office on the date 12/13 of 2019, the entire contents of which are incorporated herein by reference. Technical Field The present disclosure relates to an image sensor, and in particular, to a Complementary Metal Oxide Semiconductor (CMOS) image sensor. Background An image sensor is a semiconductor device configured to convert an optical image into an electrical signal. Image sensors can be classified into two types, a Charge Coupled Device (CCD) type and a Complementary Metal Oxide Semiconductor (CMOS) type. In general, a CMOS type image sensor is called a "CIS". The CIS includes a plurality of two-dimensionally arranged pixels, each including a Photodiode (PD) converting incident light into an electrical signal. Disclosure of Invention Embodiments of the inventive concept provide an image sensor having improved electrical and optical characteristics. According to an exemplary embodiment of the inventive concept, an image sensor includes a semiconductor substrate having a first surface and a second surface, the semiconductor substrate including a pixel region having a plurality of photoelectric conversion regions, a gate electrode disposed on the pixel region and adjacent to the first surface, a first isolation structure extending from the first surface toward the second surface, the first isolation structure including a first pixel isolation pattern surrounding the pixel region, and a first internal isolation pattern spaced apart from the first pixel isolation pattern and positioned between the plurality of photoelectric conversion regions, and a second isolation structure extending from the second surface toward the first surface, the second isolation structure having a top surface vertically spaced apart from at least a portion of a bottom surface of the first isolation structure. The bottom surface of the first isolation structure is closer to the second surface of the semiconductor substrate than the first surface of the semiconductor substrate. According to an embodiment of the inventive concept, an image sensor may include a semiconductor substrate of a first conductive type having first and second surfaces facing each other and including a plurality of pixel regions, a first pixel isolation pattern disposed in the semiconductor substrate to electrically separate the first pixel region, which is one of the pixel regions, from other pixel regions in the pixel region, a first and second photoelectric conversion regions disposed in the first pixel region and including impurities of a second conductive type different from the first conductive type, a first internal isolation pattern disposed between the first and second photoelectric conversion regions and spaced apart from the first pixel isolation pattern, a connection region disposed between the first and first internal isolation patterns to connect the first and second photoelectric conversion regions, the connection region including impurities of the second conductive type, and a second internal isolation pattern extending from the second surface toward the connection region and spaced apart from the first surface. According to an embodiment of the inventive concept, an image sensor may include a semiconductor substrate of a first conductivity type including a pixel region and having a first surface and a second surface facing each other in a first direction, a plurality of photoelectric conversion regions disposed in the pixel region and including impurities of a second conductivity type different from the first conductivity type, a gate electrode disposed on the photoelectric conversion region and adjacent to the first surface, a first isolation structure extending from the first surface toward the second surface, the first isolation structure including a first pixel isolation pattern surrounding the pixel region, and a first internal isolation pattern spaced apart from the first pixel isolation pattern and located between the plurality of photoelectric conversion regions, a second isolation structure extending from the second surface toward the first surface, the second isolation structure including a second pixel isolation pattern surrounding the pixel region, and a second internal isolation pattern connected to the second pixel isolation pattern and overlapping the pixel region, the barrier region disposed in the semiconductor substrate to cover a side surface of the first isolation structure and including the first conductivity type, and the second isolation pattern including the impurities of the first conductivity type connected between the first conductive type and the first conductive region. Drawings Example embodiments will be more clearly understood from the following brief description taken in connection with the accompanying drawings. The accomp