US-12628454-B2 - Image sensor

US12628454B2US 12628454 B2US12628454 B2US 12628454B2US-12628454-B2

Abstract

An image sensor includes a pixel division structure, a light sensing element, a planarization layer, a color filter array layer, and a microlens. The pixel division structure extends through a substrate in a vertical direction, and defines unit pixel regions where unit pixels are formed. The light sensing element is in each unit pixel region. The planarization layer is on the substrate. The color filter array layer including color filters is on the planarization layer. The microlens is on the color filter array layer. The pixel division structure includes a core extending in the vertical direction and a lateral pattern structure on a sidewall thereof. The lateral pattern structure includes a first lateral pattern on a sidewall of a lower portion of the core, an air spacer on the first lateral pattern, and a second lateral pattern on outer sidewalls of the first lateral pattern and the air spacer.

Inventors

Miseon PARK

Assignees

SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20221215
Priority Date: 20220128

Claims (20)

1 . An image sensor comprising: a pixel division structure extending through a substrate in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the substrate, the pixel division structure defining unit pixel regions in which unit pixels are respectively formed; a light sensing element in each of the unit pixel regions; a planarization layer on the substrate; a color filter array layer on the planarization layer, the color filter array layer comprising color filters; and a microlens on the color filter array layer, wherein the pixel division structure comprises: a core extending in the vertical direction; and a lateral pattern structure on an outer sidewall of the core, and wherein the lateral pattern structure comprises: a first lateral pattern on an outer sidewall of a lower portion of the core; an air spacer on the outer sidewall of the core, and on the first lateral pattern in the vertical direction; and a second lateral pattern on outer sidewalls of the first lateral pattern and on outer sidewalls of the air spacer.
2 . The image sensor of claim 1 , wherein the first lateral pattern comprises a nitride, and the second lateral pattern comprises an oxide.
3 . The image sensor of claim 1 , further comprising a third lateral pattern on the air spacer in the vertical direction.
4 . The image sensor of claim 3 , wherein the third lateral pattern comprises a material substantially the same as a material of the planarization layer.
5 . The image sensor of claim 4 , wherein the planarization layer comprises a first layer, a second layer, a third layer, a fourth layer, and a fifth layer sequentially stacked in the vertical direction, and wherein the third lateral pattern comprises a material substantially the same as a material of the first layer.
6 . The image sensor of claim 5 , wherein the third lateral pattern comprises a metal oxide.
7 . The image sensor of claim 3 , wherein the third lateral pattern comprises a material having a refractive index lower than a refractive index of a material included in the first lateral pattern.
8 . The image sensor of claim 1 , wherein the core comprises: a first filling pattern including polysilicon doped with p-type impurities or n-type impurities; and a second filling pattern in a space formed by the first filling pattern, wherein a sidewall of the second filling pattern is covered by the first filling pattern and the second filling pattern comprises polysilicon.
9 . The image sensor of claim 1 , wherein the core and the lateral pattern structure form a first filling pattern structure, and wherein the pixel division structure further comprises a second filling pattern structure under the first filling pattern structure.
10 . The image sensor of claim 9 , wherein a width of the second filling pattern structure is greater than a width of the first filling pattern structure.
11 . An image sensor comprising: a pixel division structure extending through a substrate in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the substrate, the pixel division structure defining unit pixel regions in which unit pixels are respectively formed; a light sensing element in each of the unit pixel regions; a planarization layer on the substrate; a color filter array layer on the planarization layer, the color filter array layer comprises color filters; and a microlens on the color filter array layer, wherein the pixel division structure comprises: a core extending in the vertical direction and including polysilicon; and a lateral pattern structure on an outer sidewall of the core in a horizontal direction, the outer sidewall of the core facing away from a center, in the horizontal direction, of the core, and wherein the lateral pattern structure comprises: an air spacer on the outer sidewall of the core; and a first lateral pattern on an outer sidewall of the air spacer, the first lateral pattern comprising an oxide.
12 . The image sensor of claim 11 , further comprising a second lateral pattern on the air spacer.
13 . The image sensor of claim 12 , wherein the second lateral pattern comprises a material substantially the same as a material of the planarization layer.
14 . The image sensor of claim 13 , wherein the planarization layer comprises a first layer, a second layer, a third layer, a fourth layer, and a fifth layer sequentially stacked in the vertical direction, and wherein the material of the second lateral pattern is substantially the same as a material of the first layer of the planarization layer.
15 . The image sensor of claim 14 , wherein the second lateral pattern comprises a metal oxide.
16 . The image sensor of claim 11 , wherein the core comprises: a first filling pattern comprising polysilicon doped with p-type impurities or n-type impurities; and a second filling pattern in a space formed by the first filling pattern, wherein a sidewall of the second filling pattern is covered by the first filling pattern and the second filling pattern comprises polysilicon.
17 . The image sensor of claim 11 , wherein the core and the lateral pattern structure form a first filling pattern structure, and wherein the pixel division structure further comprises a second filling pattern structure under the first filling pattern structure.
18 . An image sensor comprising: a first substrate defining a first region, a second region, a third region, and a fourth region at an inside of the first substrate and a space under and over the first substrate, the second region surrounding the first region, the third region surrounding the second region, and the fourth region surrounding the third region; a first insulating interlayer on the first substrate, the first insulating interlayer containing first wirings in the third region; a second insulating interlayer on the first insulating interlayer, the second insulating interlayer containing second wirings in the third region; a second substrate on the second insulating interlayer; a pixel division structure in the second substrate in the first region and the second region, the pixel division structure defining unit pixel regions in which unit pixels are formed, respectively; a light sensing element in each of the unit pixel regions of the second substrate; a transfer gate (TG) extending through a lower portion of the second substrate, the TG contacting the light sensing element; a floating diffusion (FD) region at the lower portion of the second substrate adjacent to the TG; a lower planarization layer on the second substrate; a color filter array layer on the lower planarization layer, the color filter array layer comprising color filters; an interference blocking structure between adjacent ones of the color filters; and a microlens on the color filter array layer, wherein the pixel division structure comprises: a core extending in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the first substrate; and a lateral pattern structure on an outer sidewall of the core, and wherein the lateral pattern structure comprises: a first lateral pattern on an outer sidewall of a lower portion of the core; an air spacer on the outer sidewall of the core, and on the first lateral pattern in the vertical direction; and a second lateral pattern on outer sidewalls of the first lateral pattern and outer sidewalls of the air spacer.
19 . The image sensor of claim 18 , further comprising: a light blocking metal pattern on the lower planarization layer in the second region; a through via structure extending through the lower planarization layer, the second substrate, the second insulating interlayer and an upper portion of the first insulating interlayer in the third region, the through via structure commonly contacting the first wirings and the second wirings; and a pad extending through the lower planarization layer and an upper portion of the second substrate in the fourth region.
20 . The image sensor of claim 19 , wherein the first region comprises an active pixel region in which active pixels are formed, the second region comprises an optical black (OB) pixel region in which OB pixels are formed, the third region comprises a stack region in which the through via structure is formed, and the fourth region comprises a pad region in which the pad is formed.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is based on and claims priority from Korean Patent Application No. 10-2022-0013202, filed on Jan. 28, 2022 in the Korean Intellectual Property Office (KIPO), the disclosure of which is incorporated herein in its entirety by reference. BACKGROUND 1. Field Example embodiments relate to an image sensor. More particularly, example embodiments relate to an image sensor including a pixel division structure. 2. Description of Related Art In an image sensor including a pixel division structure, electrons may flow at a boundary between the pixel division structure and a light sensing element to generate dark current. A negative bias may be applied to a core included in the pixel division structure, so that the flow of electrons may be captured by an impurity region to decrease the dark current. The core included in the pixel division structure may include polysilicon; however, polysilicon may have a high light absorption rate so that the efficiency of light in the image sensor may decrease. SUMMARY Example embodiments provide an image sensor having improved characteristics. In accordance with an aspect of the disclosure, an image sensor includes a pixel division structure extending through a substrate in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the substrate, the pixel division structure defining unit pixel regions in which unit pixels are respectively formed; a light sensing element in each of the unit pixel regions; a planarization layer on the substrate; a color filter array layer on the planarization layer, the color filter array layer including color filters; and a microlens on the color filter array layer, wherein the pixel division structure includes a core extending in the vertical direction; and a lateral pattern structure on a sidewall of the core, and wherein the lateral pattern structure includes a first lateral pattern on a sidewall of a lower portion of the core; an air spacer on the first lateral pattern; and a second lateral pattern on outer sidewalls of the first lateral pattern and on outer sidewalls of the air spacer. In accordance with an aspect of the disclosure, an image sensor includes a pixel division structure extending through a substrate in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the substrate, the pixel division structure defining unit pixel regions in which unit pixels are respectively formed; a light sensing element in each of the unit pixel regions; a planarization layer on the substrate; a color filter array layer on the planarization layer, the color filter array layer includes color filters; and a microlens on the color filter array layer, wherein the pixel division structure includes a core extending in the vertical direction and including polysilicon; and a lateral pattern structure on a sidewall of the core, and wherein the lateral pattern structure includes an air spacer on the sidewall of the core; and a first lateral pattern on an outer sidewall of the air spacer, the first lateral pattern including an oxide. In accordance with an aspect of the disclosure, an image sensor includes a first substrate defining a first region, a second region, a third region, and a fourth region at an inside of the first substrate and a space under and over the first substrate, the second region surrounding the first region, the third region surrounding the second region, and the fourth region surrounding the third region; a first insulating interlayer on the first substrate, the first insulating interlayer containing first wirings in the third region; a second insulating interlayer on the first insulating interlayer, the second insulating interlayer containing second wirings in the third region; a second substrate on the second insulating interlayer; a pixel division structure in the second substrate in the first region and the second region, the pixel division structure defining unit pixel regions in which unit pixels are formed, respectively; a light sensing element in each of the unit pixel regions of the second substrate; a transfer gate (TG) extending through a lower portion of the second substrate, the TG contacting the light sensing element; a floating diffusion (FD) region at the lower portion of the second substrate adjacent to the TG; a lower planarization layer on the second substrate; a color filter array layer on the lower planarization layer, the color filter array layer including color filters; an interference blocking structure between adjacent ones of the color filters; and a microlens on the color filter array layer, wherein the pixel division structure includes a core extending in a vertical direction, the vertical direction being substantially perpendicular to an upper surface of the first substrate; and a lateral pattern structure on a sidewall of the core, and wherein the lateral pattern structure i