CN110112162B - Image sensor and forming method thereof - Google Patents
Image sensor and forming method thereof Download PDFInfo
- Publication number
- CN110112162B CN110112162B CN201910412522.5A CN201910412522A CN110112162B CN 110112162 B CN110112162 B CN 110112162B CN 201910412522 A CN201910412522 A CN 201910412522A CN 110112162 B CN110112162 B CN 110112162B
- Authority
- CN
- China
- Prior art keywords
- substrate
- layer
- forming
- opening
- material film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 77
- 239000000758 substrate Substances 0.000 claims abstract description 214
- 238000002955 isolation Methods 0.000 claims abstract description 45
- 238000009792 diffusion process Methods 0.000 claims abstract description 35
- 239000000463 material Substances 0.000 claims description 93
- 230000008569 process Effects 0.000 claims description 42
- 239000003989 dielectric material Substances 0.000 claims description 22
- 238000005530 etching Methods 0.000 claims description 21
- 238000001039 wet etching Methods 0.000 claims description 15
- 238000003384 imaging method Methods 0.000 abstract description 17
- 239000010410 layer Substances 0.000 description 217
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 21
- 239000010703 silicon Substances 0.000 description 21
- 229910052710 silicon Inorganic materials 0.000 description 21
- 229910052721 tungsten Inorganic materials 0.000 description 15
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 14
- 239000010937 tungsten Substances 0.000 description 14
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 13
- 229910052802 copper Inorganic materials 0.000 description 11
- 239000010949 copper Substances 0.000 description 11
- 150000002500 ions Chemical class 0.000 description 11
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 11
- 229910010271 silicon carbide Inorganic materials 0.000 description 11
- 239000010936 titanium Substances 0.000 description 11
- 229910052719 titanium Inorganic materials 0.000 description 11
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 10
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 10
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 10
- 230000003287 optical effect Effects 0.000 description 10
- 230000004888 barrier function Effects 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 239000002356 single layer Substances 0.000 description 8
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 7
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 7
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 7
- KXNLCSXBJCPWGL-UHFFFAOYSA-N [Ga].[As].[In] Chemical compound [Ga].[As].[In] KXNLCSXBJCPWGL-UHFFFAOYSA-N 0.000 description 7
- 229910052732 germanium Inorganic materials 0.000 description 7
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 7
- 229910052581 Si3N4 Inorganic materials 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 6
- 229910052814 silicon oxide Inorganic materials 0.000 description 6
- 238000001312 dry etching Methods 0.000 description 5
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 4
- 229910000449 hafnium oxide Inorganic materials 0.000 description 4
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 description 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000000149 penetrating effect Effects 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 229910021332 silicide Inorganic materials 0.000 description 3
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000007517 polishing process Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000010944 silver (metal) Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titanium dioxide Inorganic materials O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14603—Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14625—Optical elements or arrangements associated with the device
- H01L27/14629—Reflectors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/1463—Pixel isolation structures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14643—Photodiode arrays; MOS imagers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14685—Process for coatings or optical elements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14689—MOS based technologies
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Solid State Image Pick-Up Elements (AREA)
Abstract
An image sensor and a method of forming the same, the image sensor comprising: the first substrate comprises a first surface and a second surface which are opposite, and the first substrate comprises a plurality of mutually-separated pixel regions and an isolation region positioned between adjacent pixel regions; the first reflecting structure is positioned on the second surface of the first substrate; the second reflecting structure is positioned in the isolation region and penetrates from the first surface to the second surface; the second substrate is positioned on the surface of the first reflecting structure and comprises a third surface and a fourth surface which are opposite, the third surface is contacted with the surface of the first reflecting structure, and a plurality of mutually-separated floating diffusion regions are arranged in the second substrate; and the conductive plug is positioned in the second substrate, penetrates from the pixel region into the second substrate, and is electrically connected with the floating diffusion region and the pixel region. The imaging quality of the image sensor is good.
Description
Technical Field
The invention relates to the technical field of semiconductor manufacturing and photoelectric imaging, in particular to an image sensor and a forming method thereof.
Background
Image sensors are classified into a Complementary Metal Oxide Semiconductor (CMOS) Image Sensor and a Charge Coupled Device (CCD) Image Sensor, and are generally used to convert optical signals into corresponding electrical signals. The CCD image sensor has the advantages of high image sensitivity, low noise, etc., but the CCD image sensor is difficult to be integrated with other devices, and the power consumption of the CCD image sensor is large. In contrast, the CIS has the advantages of simple process, easy integration with other devices, small volume, light weight, low power consumption, low cost, and the like. Currently, CIS has been widely used in still digital cameras, camera phones, digital video cameras, medical image pickup devices (e.g., gastroscopes), vehicle image pickup devices, and the like.
The basic photosensitive unit of the CIS is called a Pixel (Pixel) which includes one photodiode and 3 or 4 transistors. When the CIS is of a 4T type, the 4 transistors are a reset transistor, an amplifying transistor, a selection transistor, and a transfer transistor, respectively. Each pixel comprises a photosensitive area and a reading area. For a commonly used pixel (e.g., a 4T pixel), the transfer transistor transfers a signal output by the photosensitive region to a Floating Diffusion (Floating Diffusion) and then the signal remains in the Floating Diffusion until read out by a read portion of the pixel.
However, if the incident angle of the incident light above the photosensitive region is too large, photons can directly enter the adjacent pixel region, and optical crosstalk occurs, resulting in poor imaging quality of the image sensor.
Disclosure of Invention
The invention provides an image sensor and a forming method thereof, aiming at reducing optical crosstalk and improving the imaging quality of the image sensor.
To solve the above technical problem, an embodiment of the present invention provides an image sensor, including: the first substrate comprises a first surface and a second surface which are opposite, and the first substrate comprises a plurality of mutually-separated pixel regions and an isolation region positioned between adjacent pixel regions; the first reflecting structure is positioned on the second surface of the first substrate; the second reflecting structure is positioned in the isolation region and penetrates from the first surface to the second surface; the second substrate is positioned on the surface of the first reflecting structure and comprises a third surface and a fourth surface which are opposite, the third surface is contacted with the surface of the first reflecting structure, and a plurality of mutually-separated floating diffusion regions are arranged in the second substrate; and the conductive plug is positioned in the second substrate, penetrates from the pixel region into the second substrate, and is electrically connected with the floating diffusion region and the pixel region.
Optionally, the material of the first substrate includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide.
Optionally, the material of the second substrate includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide.
Optionally, the first reflective structure includes: the first dielectric layer is positioned on the second surface of the first substrate and the third surface of the second substrate; and the first reflecting layer is positioned on the surface of the first dielectric layer.
Optionally, the material of the first reflective layer includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the first reflective layer is a single-layer structure or a multi-layer stacked structure.
Optionally, a plurality of the pixel regions are arranged along a first direction; the second reflective structure includes: the structure comprises a first structure and a second structure, wherein the first structure is arranged along a first direction, the second structure is arranged along a second direction, and the second direction is vertical to the first direction.
Optionally, the first structure includes: the second dielectric layer is positioned on the surface of the isolation region, and the second reflecting layer is positioned on the surface of the second dielectric layer.
Optionally, the first structure extends from the first surface of the first substrate through the first reflective structure into the second substrate.
Optionally, the material of the second reflective layer includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the second reflecting layer is of a single-layer structure or a multi-layer stacked structure.
Optionally, the second structure includes: a third dielectric layer and a third reflective layer on the surface of the third dielectric layer.
Optionally, the material of the third reflective layer includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the third reflecting layer is of a single-layer structure or a multi-layer stacked structure.
Optionally, the method further includes: an isolation structure within the second substrate, the isolation structure comprising opposing first and second end faces; the fourth surface of the second substrate is exposed out of the second end surface of the isolation structure, and the first end surface of the isolation structure is in contact with the first structure.
Optionally, the method further includes: and the logic device is positioned on the fourth surface of the second substrate.
Correspondingly, an embodiment of the present invention further provides a method for forming an image sensor, including: providing an initial substrate, wherein the initial substrate comprises a first base with a first surface and a second surface which are opposite, a sacrificial layer positioned on the surface of the second surface of the first base, and a second base positioned on the surface of the sacrificial layer, the second base is provided with a third surface and a fourth surface which are opposite, the third surface is in contact with the surface of the sacrificial layer, and the first base comprises a plurality of pixel areas which are separated from each other and an isolation area positioned between adjacent pixel areas; forming a plurality of mutually-separated floating diffusion regions in the second substrate; forming a conductive plug in the second substrate, wherein the conductive plug penetrates into the second substrate from the pixel region and is electrically connected with the floating diffusion region and the pixel region; forming a second reflecting structure in the isolation region, wherein the second reflecting structure penetrates from the first surface to the second surface; removing the sacrificial layer, and forming a first groove between the first substrate and the second substrate; and forming a first reflecting structure in the first groove.
Optionally, a plurality of the pixel regions are arranged along a first direction; the second reflective structure includes: the structure comprises a first structure and a second structure, wherein the first structure is arranged along a first direction, the second structure is arranged along a second direction, and the second direction is vertical to the first direction.
Optionally, the method further includes: after the conductive plug is formed and before the first reflection structure and the second reflection structure are formed, forming an isolation structure in the second substrate, wherein the isolation structure comprises a first end face and a second end face which are opposite; the fourth surface of the second substrate is exposed out of the second end surface of the isolation structure, and the first end surface of the isolation structure is contacted with the surface of the first structure.
Optionally, the method further includes: after the conductive plug is formed and before the first groove is formed, a plurality of second openings are formed in the first substrate and the sacrificial layer, the bottom of each second opening is exposed out of the surface of the third surface of the second substrate, and the plurality of second openings are arranged along the first direction; the first structure includes: the second dielectric layer is positioned at the bottom of the second opening and on the surface of the side wall, and the second reflecting layer is positioned on the surface of the second dielectric layer; the forming method of the first structure comprises the following steps: forming a second dielectric material film in the second opening and on the first substrate first side surface; forming a second reflecting material film on the surface of the second medium material film, wherein the second reflecting material film fills the second opening; and flattening the second medium material film and the second reflecting material film until the top surface of the first substrate is exposed, and forming a second medium layer and a second reflecting layer positioned on the surface of the second medium layer on the bottom and the side wall surface of the second opening.
Optionally, the method for removing the sacrificial layer includes: after the conductive plug is formed and before the first groove is formed, a plurality of first openings are formed in the first substrate and the sacrificial layer, the bottom of each first opening is exposed out of the surface of the third surface of the second substrate, and the first openings are arranged along the second direction; and after the first opening is formed, removing the sacrificial layer exposed from the side wall of the first opening to form the first groove.
Optionally, the first reflective structure includes: the first dielectric layer is positioned on the surface of the inner wall of the first groove, and the first reflecting layer is positioned on the surface of the first dielectric layer; the second structure includes: the third dielectric layer is positioned at the bottom of the first opening and on the surface of the side wall, and the third reflecting layer is positioned on the surface of the third dielectric layer; the forming method of the first reflecting structure and the second reflecting structure comprises the following steps: forming a first medium material film on the bottom and side wall surfaces of the first opening, the inner wall of the first groove and the first surface of the first substrate; forming a first reflecting material film on the surface of the first medium material film, wherein the first opening and the first groove are filled with the first reflecting material film; and flattening the first medium material film and the first reflection material film until the first surface of the first substrate is exposed, forming a first medium layer and a first reflection layer positioned on the surface of the first medium layer on the surface of the inner wall of the first groove, and forming a third medium layer and a third reflection layer positioned on the surface of the third medium layer on the bottom and the surface of the side wall of the first opening.
Optionally, the material of the sacrificial layer is different from that of the first substrate, and the material of the sacrificial layer is different from that of the second substrate; the process of etching and removing the sacrificial layer exposed out of the side wall of the first opening is a wet etching process; the etching rate of the wet etching process to the sacrificial layer is greater than that to the first substrate, and the etching rate of the wet etching process to the sacrificial layer is greater than that to the second substrate.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following beneficial effects:
in the image sensor provided by the invention, the first reflection structure is positioned between the first substrate and the second substrate, the second reflection structure is positioned in the isolation region of the first substrate, and the second reflection structure penetrates from the first surface to the second surface, namely, the periphery and the bottom of the pixel region are surrounded by the first reflection structure and the second reflection structure. Therefore, the first reflecting structure and the second reflecting structure surrounding the pixel regions can reflect light rays from adjacent pixel regions, so that optical crosstalk between the adjacent pixel regions can be effectively prevented. And the second substrate is positioned on the surface of the first reflection structure on the second surface of the first substrate, and a plurality of mutually-separated floating diffusion regions are arranged in the second substrate, namely, the floating diffusion regions and the pixel region are not positioned in the same substrate, so that the floating diffusion regions can be prevented from restricting the area of the pixel region, the area of the pixel region is increased, and the photoelectric conversion efficiency can be improved. In conclusion, the imaging quality of the image sensor is better.
Furthermore, the first structure penetrates through the first reflection structure from the first surface of the first substrate and extends into the second substrate, and the first structure can reflect light, so that the light penetrating through the pixel region can be prevented from entering the adjacent floating diffusion region by the first structure, optical crosstalk is effectively prevented, and the imaging quality of the image sensor is good.
Further, when light is incident from the first surface of the first substrate, the first reflective structure is located at the bottom of the photodiode because the first reflective structure is located on the second surface of the first substrate and the pixel region of the first substrate is used for forming the photodiode. When part of incident light is not absorbed by the photodiode and continues to irradiate downwards, the first reflection structure can reflect the part of incident light, so that light rays which are not absorbed by the photodiode return to the photodiode again, and then enter the photodiode to perform photoelectric conversion again, the photoelectric conversion efficiency is further improved, and the imaging quality of the image sensor is better.
Drawings
FIG. 1 is a schematic diagram of an embodiment of an image sensor;
fig. 2 to 23 are schematic cross-sectional views illustrating steps of a method for forming an image sensor according to an embodiment of the invention.
Detailed Description
As described in the background, the image sensor has poor imaging quality and will now be described in detail with reference to specific embodiments.
Fig. 1 is a schematic structural diagram of an embodiment of an image sensor.
Referring to fig. 1, a substrate 100, the substrate 100 includes a plurality of pixel regions a separated from each other, and an isolation region located between adjacent pixel regions a; a photo-electric doping region 110 and a floating diffusion region 120 in the pixel region a of the substrate 100; an isolation structure 130 located on the surface of the isolation region of the substrate 100 and in the pixel region a; a filter layer 140 on the surface of the pixel region a isolation structure 130; a reflective structure 150 positioned between adjacent filter layers 140; and a microlens 160 disposed on a surface of the filter layer 150.
In the image sensor, the reflective structure 150 between the adjacent filter layers 140 has a reflective effect on the light 101, and therefore, the reflective structure 120 can reduce the light 101 entering the adjacent pixel area a through the filter layers 140, so as to reduce the light crosstalk.
However, after the light 101 passes through the filter layer 140, a part of the light 101 from the adjacent pixel area a cannot be effectively reflected by the reflective structure 150, so that a part of the light 101 enters the adjacent pixel area a through the isolation structure 130 located at the bottom of the reflective structure 140, which causes a problem of light crosstalk between different pixel areas a, and the image quality of the image sensor is poor.
In order to solve the technical problem, the technical scheme of the invention provides an image sensor which can effectively reduce optical crosstalk and has good imaging quality.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Fig. 2 to 23 are schematic cross-sectional views illustrating steps of a method for forming an image sensor according to an embodiment of the invention.
Referring to fig. 2, an initial substrate (not shown) is provided, the initial substrate includes a first base 212 having a first side 201 and a second side 202, a sacrificial layer 211 located on a surface of the second side 202 of the first base 212, and a second base 213 located on a surface of the sacrificial layer 211, the second base has a third side 203 and a fourth side 204, the third side is in contact with the surface of the sacrificial layer 211, and the first base includes a plurality of pixel regions a separated from each other and an isolation region (not shown) located between adjacent pixel regions a.
The material of the sacrificial layer 211 includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide. In this embodiment, the material of the sacrificial layer 211 is: silicon germanium.
The material of the first substrate 212 is different from the material of the sacrificial layer 211, and the material of the first substrate 212 includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide. In this embodiment, the first substrate 212 is made of: silicon, the first substrate 212 is formed using a selective epitaxy process.
Because the material of the sacrificial layer 211 is different from that of the first substrate 212, the subsequent etching process is facilitated, and the etching damage to the first substrate 212 is small when the sacrificial layer 211 is removed.
The material of the second substrate 213 is different from the material of the sacrificial layer 211, and the material of the second substrate 213 includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide. In this embodiment, the material of the second substrate 213 is the same as the material of the first substrate 212, and is silicon.
Because the material of the sacrificial layer 211 is different from the material of the second substrate 213, the material of the sacrificial layer 211 is different from the material of the first substrate 211, which is beneficial to the subsequent etching process, and the etching damage to the second substrate 213 is small when the sacrificial layer 211 is removed.
The sacrificial layer 211 is located between the first substrate 212 and the second substrate 213, and the sacrificial layer 211 is used for forming a first reflective structure.
The first substrate 212 is used for subsequently forming an image sensing element. In this embodiment, the image sensing element includes: a photodiode.
In the present embodiment, the first substrate 212 has first doping ions therein, and the first doping ions are related to the type of the pixel structure of the image sensor. The pixel region a of the first substrate 212 further has a photo-electric doped region (not shown) therein, and the photo-electric doped region has second doping ions therein, wherein the conductivity type of the second doping ions is opposite to the conductivity type of the first doping ions.
The second doping ions in the photoelectric doping region have a conductivity type opposite to that of the first doping ions in the first substrate 212, and constitute a photodiode, which is used for realizing photoelectric conversion.
The second substrate 213 is used to subsequently form an image sensing element. In this embodiment, the image sensing element includes: a floating diffusion region.
In this embodiment, the fourth surface 204 of the second substrate 213 further has a first protection layer 214.
The first protective layer 214 is used to protect the surface of the second substrate 213, so that certain damage to the surface of the second substrate 213 due to a later process can be avoided, and the imaging quality of the formed image sensor can be improved.
The material of the first protective layer 214 includes: silicon oxide, silicon nitride, silicon carbonitride, silicon carbide, aluminum oxide, hafnium oxide, silicon oxynitride, or silicon oxycarbide.
Subsequently, a conductive plug is formed in the second substrate, the conductive plug penetrates into the second substrate from the pixel region, and the conductive plug is electrically connected to the floating diffusion region and the pixel region, and refer to fig. 3 to 8 for a process of forming the conductive plug.
Referring to fig. 3, a first mask layer (not shown) is formed on the surface of the second substrate 213, and the first mask layer exposes a portion of the surface of the second substrate 213 in the pixel region a; etching the second substrate 213 and the sacrificial layer 211 by using the first mask layer as a mask until the surface of the second surface 202 of the first substrate 212 is exposed, and forming a third opening 220 in the sacrificial layer 211 and the second substrate 213; after the third opening 220 is formed, the first mask layer is removed.
Specifically, the first mask layer is formed on the surface of the first protection layer 214, and the first mask layer exposes a portion of the surface of the first retention layer 214.
The process of etching the second substrate 213 and the sacrificial layer 211 includes: one or both of a wet etching process and a dry etching process.
The material of the first mask layer comprises: a photoresist layer, silicon oxide, silicon nitride or titanium nitride; in this embodiment, the first mask layer is made of: and (7) photoresist.
Referring to fig. 4, a film 230 of initial dielectric material is formed on the bottom and sidewall surfaces of the third opening 220 and the surface of the second substrate 213.
The initial dielectric material film 230 is used for forming a fourth dielectric layer later.
The materials of the initial dielectric material film 230 include: silicon oxide, silicon nitride, silicon carbonitride, silicon carbide, aluminum oxide, hafnium oxide, silicon oxynitride, or silicon oxycarbide; in this embodiment, the material of the initial dielectric material film 230 is silicon oxide.
Referring to fig. 5, the initial dielectric material film 230 on the bottom surface of the third opening 220 and the surface of the second substrate 213 is removed until the surface of the first substrate 212 is exposed, and a fourth dielectric layer 231 is formed on the sidewall surface of the third opening 220.
The process of removing the initial dielectric material film 230 from the bottom surface of the third opening 220 and the surface of the second substrate 213 includes: one or both of a dry etching process and a wet etching process.
In this embodiment, the process of removing the initial dielectric material film 230 is: anisotropic dry etching process.
The fourth dielectric layer 231 is used to isolate the subsequently formed conductive plug from the second substrate 213 and the first reflective structure.
Referring to fig. 6, an initial barrier film 240 is formed on the bottom of the third opening 220 and the surface of the fourth dielectric layer 231.
In this embodiment, the initial barrier film 240 is a multi-layer structure, and includes a metal silicide layer (not shown) on the bottom surface of the third opening 220 and a barrier film (not shown) on the surface of the metal silicide layer and the surface of the sidewall of the fourth dielectric layer 231.
The metal silicide layer serves to reduce contact resistance between the conductive plug and the second substrate 213.
The barrier film is used to prevent corrosion of the fourth dielectric layer by a byproduct generated when a conductive layer is subsequently formed in the third opening 220.
Referring to fig. 7, a conductive material film 250 is formed on the surface of the initial barrier film 240, and the conductive material film 250 fills the third opening 220.
The conductive material film 250 is used for the subsequent formation of a conductive layer.
The material of the conductive material film 250 includes: al, Cu, Ag, Au, Ni, Ti, W, WN or WSi. In this embodiment, the material of the conductive material film 250 is tungsten, and correspondingly, the material of the subsequently formed conductive layer is tungsten.
Referring to fig. 8, the initial barrier film 240 and the conductive material film 250 are planarized until the fourth surface 204 of the second substrate 213 is exposed, forming a barrier layer 241 and a conductive layer 251.
In this embodiment, the conductive plug (not shown in the figure) includes: a fourth dielectric layer 231, a barrier layer 241 on the surface of the fourth dielectric layer 231, and a conductive layer 251 on the surface of the barrier layer 241.
In other embodiments, the conductive plug includes: a fourth dielectric layer and a conductive layer on the surface of the fourth dielectric layer.
In this embodiment, the method for forming the image sensor further includes: and forming a floating diffusion region in the second substrate after the conductive plug is formed and before the first reflecting structure is formed subsequently.
Referring to fig. 9, a floating diffusion region 2131 is formed in the second substrate 213. The process of forming the floating diffusion region 2131 includes: and (5) an ion implantation process.
In this embodiment, the second substrate 213 has third doping ions therein, the floating diffusion region 2131 has fourth doping ions therein, and the conductivity type of the fourth doping ions is opposite to the conductivity type of the third doping ions.
The third surface 203 of the second substrate 213 is in contact with the surface of the sacrificial layer 211, and a floating diffusion area 2131 is arranged in the second substrate 213; the second surface 202 of the first substrate 212 is in contact with the sacrificial layer 211, and the first substrate 212 has a photo-electric doped region therein. Because the floating diffusion region 2131 and the photoelectric doped region are not in the same substrate, the floating diffusion region 2131 can be prevented from limiting the area of the pixel region a, so that the area of the pixel region a can be correspondingly increased, the photoelectric conversion efficiency can be improved, and the imaging quality of the image sensor can be improved.
In this embodiment, after forming the conductive plug and before subsequently forming the first reflective structure and the second reflective structure, the method further includes: forming insulation structures 2132 within the second substrate, the insulation structures 2132 comprising opposing first and second end faces 205, 206; the fourth surface 204 of the second substrate 213 exposes the second end surface 206 of the isolation structure 2132, and the first end surface 205 of the isolation structure 2132 contacts with a subsequently formed first structure surface.
The isolation structure 2132 is used for realizing electrical isolation between adjacent pixel regions a.
In this embodiment, after forming the conductive plug and before subsequently forming the first reflective structure and the second reflective structure, the method further includes: forming a logic device 300 on the fourth surface 204 of the second substrate 213; after the logic device 300 is formed, the first side 201 of the first substrate 212 is thinned.
In this embodiment, the method for thinning the first side 201 of the first substrate 212 includes: providing a handling substrate (not shown in the figure), and bonding the surface of the logic device 300 with the handling substrate (not shown in the figure); after the bonding, the first substrate 212 is thinned from the first face 201.
In this embodiment, after the thinning process, a second reflective structure is formed in the isolation region, and the second reflective structure penetrates from the first surface to the second surface.
In this embodiment, a plurality of the pixel regions are arranged along a first direction; the second reflective structure includes: the device comprises a first structure and a second structure, wherein the first structure is arranged along a first direction, the second structure is arranged along a second direction, and the second direction is vertical to the first direction.
Please refer to fig. 10 to fig. 13 for a process of forming the first structure.
Referring to fig. 10, a plurality of second openings 260 are formed in the first substrate 212 and the sacrificial layer 211, the bottom of the second openings 260 exposes the surface of the third surface 203 of the second substrate 213, and the plurality of second openings 260 are arranged along the first direction X.
In this embodiment, the second opening 260 is further located in the second substrate 213, and the bottom of the second opening 260 exposes the first end surface 205 of the isolation structure 2132.
In another embodiment, the first opening is only located in the first substrate and the sacrificial layer, and the bottom of the first opening exposes the third surface of the second substrate.
In this embodiment, before forming the second opening 260, the method further includes: a hard mask layer 261 is formed on the surface of the first substrate 212.
The hard mask layer 261 functions to protect the surface of the first substrate 212, so as to prevent the surface of the first substrate 212 from being damaged by a subsequent etching process; on the other hand, after the first and second reflective structures are formed subsequently, the hard mask layer 261 is removed to expose the top surface of the first substrate 212, and then a filter layer is formed on the surface of the first substrate 212, so that the hard mask layer 261 can occupy space for the subsequent formation of the filter layer.
The hard mask layer 261 comprises the following materials: SiN, TiO2TiN, AlN or Al2O3In this embodiment, the hard mask layer 261 is made of silicon nitride.
The method for forming the second opening 260 includes: forming a second mask layer (not shown in the figure) on the surface of the hard mask layer 261, wherein the second mask layer exposes the surface of the hard mask layer 261 on the isolation region; etching the sacrificial layer 211, the first substrate 212 and the second substrate 213 with the second mask layer as a mask until the top surface of the isolation structure 2132 is exposed to form the second openings 260, wherein the second openings 260 are arranged along a first direction X; after the second opening 260 is formed, the second mask layer is removed.
Referring to fig. 11, a second dielectric material film 271 is formed in the second opening 260 and on the surface of the first side 201 of the first substrate 212.
Specifically, the second dielectric material film 271 is formed in the second opening 260 and on the surface of the hard mask layer 261.
The second dielectric material film 271 is used for forming a second dielectric layer later.
The material of the second medium material film 271 includes: silicon oxide, silicon nitride, silicon carbonitride, silicon carbide, aluminum oxide, hafnium oxide, silicon oxynitride, or silicon oxycarbide.
Referring to FIG. 12, a second reflective material film 272 is formed on the surface of the second dielectric material film 271, and the second reflective material film 272 fills the second opening 260.
The material of the second reflective material film 272 includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten.
In the present embodiment, the second reflective material film 272 has a multilayer stack structure, which is a stack structure formed of two materials, i.e., titanium nitride and tungsten.
In other embodiments, the second film of reflective material is a single layer structure.
Since the material of the second reflective material film 272 is reflective to light, the second reflective material film 272 is used for the subsequent formation of a second reflective layer, i.e., the second reflective layer is reflective to light, so that the subsequently formed second structure can be reflective to light.
Referring to fig. 13, the second dielectric material film 271 and the second reflective material film 272 are planarized until the surface of the first side 201 of the first substrate 212 is exposed, and a second dielectric layer 2711 and a second reflective layer 2721 on the surface of the second dielectric layer 2711 are formed in the second opening 260 (shown in fig. 12).
In the present embodiment, the second dielectric material film 271 and the second reflective material film 272 are planarized until the top surface of the hard mask layer 261 is exposed.
The first structure (not shown in the figures) comprises: a second dielectric layer 2711 on the surface of the isolation region and a second reflective layer 2721 on the surface of the second dielectric layer.
The method of planarizing the second dielectric material film 271 and the second reflective material film 272 includes: and (5) carrying out a chemical mechanical polishing process.
In this embodiment, the first structure is further located in the second substrate 213, and the first structure extends from the first surface 201 of the first substrate 212 into the second substrate 213 through the subsequently formed first reflective structure.
Because the first structure extends from the first surface 201 of the first substrate 212 to the second substrate 213 through the first reflective structure, and the first structure can reflect light, the first structure can prevent the light transmitted through the pixel region a from entering the adjacent floating diffusion region formed subsequently, so as to effectively prevent optical crosstalk, and further, the imaging quality of the image sensor is better.
After the first structures are formed, a plurality of second structures are formed in the first substrate isolation region, the second structures penetrate through the first surface to the second surface, and the second structures are arranged along a second direction.
After the first structure is formed, removing the sacrificial layer, and forming a first groove between the first substrate and the second substrate; and forming a first reflecting structure in the first groove.
In this embodiment, in the process of forming the second structure, the first reflective structure is formed, and in particular, the process of forming the second structure and the first reflective structure is shown in fig. 14 to 21.
Referring to fig. 14 and 15, fig. 14 is a schematic view of fig. 15 taken along a tangential direction X1-X2, fig. 15 is a top view of fig. 14 taken along a direction Z, the view directions of fig. 14 and 13 are the same, a plurality of first openings 282 are formed in the sacrificial layer 211 and the first substrate 212, the bottom of the first openings 282 are exposed on the surface of the third surface 203 of the second substrate 213, and the plurality of first openings 282 are arranged along the second direction Y.
In the embodiment, the first opening 282 is formed in the hard mask layer 261, the sacrificial layer 211 and the first substrate 212, and the first opening 282 exposes the top surface of the second substrate 213, and the top surface and a portion of the sidewall surface of the conductive plug.
The method for forming the first opening 282 includes: forming a third mask layer (not shown in the figure) on the surface of the hard mask layer 261, wherein the third mask layer exposes a part of the surface of the hard mask layer 261; etching the hard mask layer 261, the sacrificial layer 211 and the first substrate 212 by using the third mask layer as a mask until the surface of the second substrate 213 is exposed to form the first openings 282, wherein the first openings 282 are arranged along a second direction Y; after the first opening 280 is formed, the third mask layer is removed.
The process of etching the sacrificial layer 211 and the first substrate 212 includes: one or both of a dry etching process and a wet etching process.
Referring to fig. 16 and 17, fig. 16 is a schematic view of fig. 17 taken along a tangential direction of Y1-Y2, the view directions of fig. 17 and 15 are the same, after the first opening 282 is formed, the sacrificial layer 211 exposed by the sidewall of the first opening 282 is etched to remove, so as to form a first groove 281, and the first groove 281 is communicated with the first opening 282.
In this embodiment, the process of removing the sacrificial layer 211 exposed by the sidewall of the first opening 282 by etching includes: and (5) wet etching process. The parameters of the wet etching process comprise: the etching solution includes HNO3(70％)、HF(49％)、CH3COOH (99.9%) and H2O, and HNO3(70％)：HF(49％)：CH3COOH(99.9％)：H2The volume ratio of O is 40:1:2: 57.
Because the material of the sacrificial layer 211 is different from that of the first substrate 212, and the material of the sacrificial layer 211 is different from that of the second substrate 213, it can be achieved that the etching rate of the wet etching process on the sacrificial layer 211 is greater than that of the first substrate 212, and the etching rate of the wet etching process on the sacrificial layer 211 is greater than that of the second substrate 213, therefore, the etching solution adopted by the wet etching process can remove only the sacrificial layer 211 located between the first substrate 212 and the second substrate 213 in the pixel region a through the first opening 282, so that the first groove 281 is formed in the pixel region a, and the first groove 281 is communicated with the first opening 282.
Referring to fig. 18, fig. 18 is a schematic view based on fig. 16, after the first recess 281 and the first opening 282 are formed, a first dielectric material film 284 is formed on the inner wall surface of the first recess 281, the bottom and side wall surfaces of the first opening 282, and the surface of the first substrate 212.
Specifically, the first dielectric material film 284 is formed on the peripheral surface of the first recess 281, the bottom and sidewall surfaces of the first opening 282, and the surface of the hard mask layer 261.
The first dielectric material film 284 is used for the subsequent formation of a first dielectric layer and a third dielectric layer.
The materials of the first media material film 284 include: silicon oxide, silicon nitride, silicon carbonitride, silicon carbide, aluminum oxide, hafnium oxide, silicon oxynitride, or silicon oxycarbide.
Referring to fig. 19, fig. 19 is a schematic view based on fig. 18, wherein a first reflective material film 285 is formed on the surface of the first dielectric material film 284, and the first reflective material film 285 fills the first opening 282 and the first recess 281.
The first reflective material film 285 is used for the subsequent formation of a first reflective layer and a third reflective layer.
The materials of the first reflective material film 285 include: titanium, copper, aluminum, titanium nitride, or tungsten.
The first reflective material film 285 may be a stacked structure formed of one or more of titanium, copper, aluminum, titanium nitride, or tungsten, or may be a single-layer structure formed of one or more of titanium, copper, aluminum, titanium nitride, or tungsten.
In the present embodiment, the first reflective material film 285 is a stack structure formed by two materials, i.e., titanium nitride and tungsten.
Since the material of the first reflective material film 285 is reflective to light, the first reflective material film 285 is used for the subsequent formation of the second reflective layer and the third reflective layer, so that the subsequently formed second structure and the first reflective structure can be reflective to light.
Referring to fig. 20 and 21, fig. 20 is a schematic view based on fig. 19, and fig. 21 is a view in the same direction as fig. 17, in which the first dielectric material film 284 and the first reflective material film 285 are planarized until the surface of the first substrate 212 is exposed, a third dielectric layer 2821 and a third reflective layer 2822 on the surface of the third dielectric layer 2821 are formed on the bottom and the sidewall surfaces of the first opening 282, and a first dielectric layer 2831 and a first reflective layer 2832 on the surface of the first dielectric layer 2831 are formed on the inner wall surfaces of the first recess 281.
In this embodiment, the first dielectric material film 284 and the first reflective material film 285 are planarized until the surface of the hard mask layer 261 is exposed, so as to form the third dielectric layer 2821, the third dielectric layer 2822, the first dielectric layer 2831 and the first reflective layer 2832.
In this embodiment, the second structure (not shown in the figure) includes: a third dielectric layer 2821 on the bottom and sidewall surfaces of the first opening 282 and a third reflective layer 2822 on the surface of the third dielectric layer 2821; the first reflecting structure (not shown in the figure) comprises: a first dielectric layer 2831 on the inner wall surface of the first recess 281, and a first reflective layer 2832 on the surface of the first dielectric layer 2831.
Since the first reflective structure is located between the first substrate 212 and the second substrate 213, the second reflective structure is located in the isolation region of the first substrate 212, and the second reflective structure penetrates from the first surface to the second surface, that is, the periphery and the bottom of the pixel region a are surrounded by the first reflective structure and the second reflective structure. Therefore, the first and second reflective structures surrounding the pixel region a can reflect light from the adjacent pixel regions a, thereby effectively preventing optical crosstalk between the adjacent pixel regions a. Moreover, the second substrate 213 is located on the first reflective structure surface of the second surface 202 of the first substrate 212, and the second substrate 213 has a plurality of floating diffusion regions 2131 separated from each other, i.e., the floating diffusion regions 2131 and the pixel region a are not located in the same substrate, so that the floating diffusion regions 2131 can be prevented from restricting the area of the pixel region a, thereby increasing the area of the pixel region a and further improving the photoelectric conversion efficiency. In conclusion, the imaging quality of the image sensor is better.
Furthermore, the first structure extends from the first surface 201 of the first substrate 212 to the second substrate 213 through the first reflective structure, and the first structure can reflect light, so that the first structure can prevent the light transmitted through the pixel region a from entering the adjacent floating diffusion region 2131, thereby effectively preventing optical crosstalk, and further improving the imaging quality of the image sensor.
Further, when light is incident from the first side 201 of the first substrate 212, the first reflective structure is located at the bottom of the photodiode because the first reflective structure is located on the surface of the second side 202 of the first substrate 212 and the pixel region a of the first substrate 212 is used to form the photodiode. When part of incident light is not absorbed by the photodiode and continues to irradiate downwards, the first reflection structure can reflect the part of incident light, so that light rays which are not absorbed by the photodiode return to the photodiode again, and then enter the photodiode to perform photoelectric conversion again, the photoelectric conversion efficiency is further improved, and the imaging quality of the image sensor is better.
In this embodiment, after the second reflective structure and the first reflective structure are formed, a filter layer is formed on the surface of the first surface 201 of the pixel region a of the first substrate 212, and the filter layer is located between adjacent first reflective structures, and please refer to fig. 22 to 23 for a process of forming the filter layer.
Referring to fig. 22, fig. 22 is a schematic view based on fig. 20, after the second reflective structure and the first reflective structure are formed, the hard mask layer 261 is removed to expose the top surface of the first substrate 212, and a fourth opening 291 is formed between the adjacent first structure and the second structure.
The process of removing the hard mask layer 261 includes: one or both of a wet etching process and a dry etching process.
The fourth opening 291 is used for forming a filter layer, and the filter layer is located between the adjacent first structures and between the adjacent second structures because the fourth opening 291 is located between the adjacent first structures and the adjacent second structures.
Referring to fig. 23, a filter layer 292 is formed in the fourth opening 291 (shown in fig. 22).
The color of the filter layer 292 includes one of red, green and blue, and only one color of the filter layer 292 is formed between the adjacent first structures and between the adjacent second structures, so that incident light irradiated onto the surface of the photoelectric doped region after being transmitted through the filter layer 292 is monochromatic light.
Because the first structure and the second structure are reflective to light, the first structure and the second structure between adjacent filter layers 292 can prevent the light-transmitting filter layer 292 from entering the adjacent photoelectric doped region, thereby reducing light crosstalk and improving the imaging quality of the image sensor.
In this embodiment, the method further includes: after the filter layer 292 is formed, microlenses 293 are formed on the surface of the filter layer 292.
The micro lens 293 is used for focusing light, so that the incident light passing through the filter layer 292 can irradiate the photoelectric doped region.
After the first and second structures are formed and before the filter layer 292 is formed, the method further includes: a second passivation layer (not shown) is formed on the first structure, the second structure and the surface of the first substrate 212.
The second protective layer serves to prevent the filter layer 292 from being contaminated by the first structure and the second structure.
Accordingly, an embodiment of the present invention further provides an image sensor, please continue to refer to fig. 20, including: the display device comprises a first substrate 212, wherein the first substrate 212 comprises a first surface 201 and a second surface 202 which are opposite to each other, and the first substrate 212 comprises a plurality of pixel areas A which are separated from each other and an isolation area which is positioned between the adjacent pixel areas A; a first reflective structure on the second side 202 of the first substrate 212; a second reflective structure located in the isolation region and penetrating from the first side 201 to the second side 202; a second substrate 213 disposed on the surface of the first reflective structure, wherein the second substrate 213 includes a third surface 203 and a fourth surface 204 opposite to each other, the third surface 203 is in contact with the surface of the first reflective structure, and the second substrate 213 has a plurality of floating diffusion regions 2131 separated from each other therein; a conductive plug in the second substrate 213, the conductive plug penetrating from the pixel region a into the second substrate 213, and the conductive plug electrically connected to the floating diffusion region 2131 and the pixel region a.
Since the first reflective structure is located between the first substrate 212 and the second substrate 213, the second reflective structure is located in the isolation region of the first substrate 212, and the second reflective structure penetrates from the first surface 201 to the second surface 202, that is, the periphery and the bottom of the pixel region a are surrounded by the first reflective structure and the second reflective structure. Therefore, the first and second reflective structures surrounding the pixel region a can reflect light from the adjacent pixel regions a, thereby effectively preventing optical crosstalk between the adjacent pixel regions a. Moreover, the second substrate 213 is located on the first reflective structure surface of the second surface 202 of the first substrate 212, and the second substrate 213 has a plurality of floating diffusion regions 2131 separated from each other, i.e., the floating diffusion regions 2131 and the pixel region a are not located in the same substrate, so that the floating diffusion regions 2131 can be prevented from restricting the area of the pixel region a, thereby increasing the area of the pixel region a and further improving the photoelectric conversion efficiency. In conclusion, the imaging quality of the image sensor is better.
The following is a detailed description:
the materials of the first substrate 212 include: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide.
The material of the second substrate 213 includes: silicon, germanium, silicon carbide, gallium arsenide, or indium gallium arsenide.
The first reflective structure includes: a first dielectric layer 2831 on the surfaces of the second face 202 of the first substrate 212 and the third face 203 of the second substrate 213; and a first reflective layer 2832 on a surface of the first dielectric layer.
The material of the first reflective layer 2831 includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the first reflective layer 2831 has a single-layer structure or a multi-layer stacked structure.
A plurality of pixel regions A are arranged along a first direction X; the second reflective structure includes: the device comprises a first structure and a second structure, wherein the first structure is arranged along a first direction X, the second structure is arranged along a second direction Y, and the second direction Y is vertical to the first direction X.
The first structure includes: a second dielectric layer 2711 on the surfaces of the isolation regions and a second reflective layer 2721 on the surface of the second dielectric layer 2711.
In this embodiment, the first structure extends from the first side 201 of the first substrate 212 through the first reflective structure and into the second substrate 213.
The material of the second reflective layer 2721 includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the second reflective layer 2721 is a single layer structure or a multilayer stacked structure.
The second structure includes: a third dielectric layer 2821 and a third reflective layer 2822 on the surface of the third dielectric layer 2821.
The material of the third reflective layer 2822 includes: one or more of titanium, copper, aluminum, titanium nitride or tungsten; the third reflective layer 2822 has a single-layer structure or a multi-layer stacked structure.
The image sensor further includes: a separation structure 2132 within the second substrate 213, the separation structure 2132 comprising opposing first and second end faces 205, 206; the fourth surface 204 of the second substrate 213 exposes the second end surface 206 of the isolation structure, and the first end surface 205 of the isolation structure 2132 contacts the first structure.
The image sensor further includes: and the logic device 300 is positioned on the surface of the fourth surface 204 of the second substrate 213.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (7)
1. A method of forming an image sensor, comprising:
providing an initial substrate, wherein the initial substrate comprises a first base with a first surface and a second surface which are opposite, a sacrificial layer positioned on the surface of the second surface of the first base, and a second base positioned on the surface of the sacrificial layer, the second base is provided with a third surface and a fourth surface which are opposite, the third surface is in contact with the surface of the sacrificial layer, and the first base comprises a plurality of pixel areas which are separated from each other and an isolation area positioned between adjacent pixel areas;
forming a plurality of mutually-separated floating diffusion regions in the second substrate;
forming a conductive plug in the second substrate, wherein the conductive plug penetrates into the second substrate from the pixel region and is electrically connected with the floating diffusion region and the pixel region;
forming a second reflecting structure in the isolation region, wherein the second reflecting structure penetrates from the first surface to the second surface;
removing the sacrificial layer, and forming a first groove between the first substrate and the second substrate;
and forming a first reflecting structure in the first groove.
2. The method of claim 1, wherein a plurality of the pixel regions are arranged in a first direction; the second reflective structure includes: the structure comprises a first structure and a second structure, wherein the first structure is arranged along a first direction, the second structure is arranged along a second direction, and the second direction is vertical to the first direction.
3. The method of forming an image sensor of claim 2, further comprising: after the conductive plug is formed and before the first reflection structure and the second reflection structure are formed, forming an isolation structure in the second substrate, wherein the isolation structure comprises a first end face and a second end face which are opposite; the fourth surface of the second substrate is exposed out of the second end surface of the isolation structure, and the first end surface of the isolation structure is contacted with the surface of the first structure.
4. The method of forming an image sensor of claim 2, further comprising: after the conductive plug is formed and before the first groove is formed, a plurality of second openings are formed in the first substrate and the sacrificial layer, the bottom of each second opening is exposed out of the surface of the third surface of the second substrate, and the plurality of second openings are arranged along the first direction; the first structure includes: the second dielectric layer is positioned at the bottom of the second opening and on the surface of the side wall, and the second reflecting layer is positioned on the surface of the second dielectric layer; the forming method of the first structure comprises the following steps: forming a second dielectric material film in the second opening and on the first substrate first side surface; forming a second reflecting material film on the surface of the second medium material film, wherein the second reflecting material film fills the second opening; and flattening the second medium material film and the second reflecting material film until the top surface of the first substrate is exposed, and forming a second medium layer and a second reflecting layer positioned on the surface of the second medium layer on the bottom and the side wall surface of the second opening.
5. The method of forming an image sensor as claimed in claim 2, wherein the method of removing the sacrificial layer comprises: after the conductive plug is formed and before the first groove is formed, a plurality of first openings are formed in the first substrate and the sacrificial layer, the bottom of each first opening is exposed out of the surface of the third surface of the second substrate, and the first openings are arranged along the second direction; and after the first opening is formed, removing the sacrificial layer exposed from the side wall of the first opening to form the first groove.
6. The method of forming an image sensor as in claim 5, wherein the first reflective structure comprises: the first dielectric layer is positioned on the surface of the inner wall of the first groove, and the first reflecting layer is positioned on the surface of the first dielectric layer; the second structure includes: the third dielectric layer is positioned at the bottom of the first opening and on the surface of the side wall, and the third reflecting layer is positioned on the surface of the third dielectric layer; the forming method of the first reflecting structure and the second reflecting structure comprises the following steps: forming a first medium material film on the bottom and side wall surfaces of the first opening, the inner wall of the first groove and the first surface of the first substrate; forming a first reflecting material film on the surface of the first medium material film, wherein the first opening and the first groove are filled with the first reflecting material film; and flattening the first medium material film and the first reflection material film until the first surface of the first substrate is exposed, forming a first medium layer and a first reflection layer positioned on the surface of the first medium layer on the surface of the inner wall of the first groove, and forming a third medium layer and a third reflection layer positioned on the surface of the third medium layer on the bottom and the surface of the side wall of the first opening.
7. The method of forming an image sensor according to claim 5, wherein a material of the sacrifice layer is different from a material of the first substrate, and a material of the sacrifice layer is different from a material of the second substrate; the process of etching and removing the sacrificial layer exposed out of the side wall of the first opening is a wet etching process; the etching rate of the wet etching process to the sacrificial layer is greater than that to the first substrate, and the etching rate of the wet etching process to the sacrificial layer is greater than that to the second substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910412522.5A CN110112162B (en) | 2019-05-17 | 2019-05-17 | Image sensor and forming method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910412522.5A CN110112162B (en) | 2019-05-17 | 2019-05-17 | Image sensor and forming method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110112162A CN110112162A (en) | 2019-08-09 |
| CN110112162B true CN110112162B (en) | 2021-11-30 |
Family
ID=67490731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910412522.5A Active CN110112162B (en) | 2019-05-17 | 2019-05-17 | Image sensor and forming method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110112162B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102332457A (en) * | 2011-01-21 | 2012-01-25 | 香港应用科技研究院有限公司 | High ligh efficiency cmos image sensor |
| CN103378112A (en) * | 2012-04-26 | 2013-10-30 | 台湾积体电路制造股份有限公司 | Image sensor device and method |
| CN106169488A (en) * | 2015-05-22 | 2016-11-30 | 台湾积体电路制造股份有限公司 | The vertical transitions grid structure of backside illumination (BSI) complementary metal oxide semiconductors (CMOS) (CMOS) imageing sensor for using global shutter to capture |
| CN108257985A (en) * | 2016-12-28 | 2018-07-06 | 三星电子株式会社 | Optical sensor |
| CN108695347A (en) * | 2017-04-03 | 2018-10-23 | 豪威科技股份有限公司 | The crosstalk of high dynamic range image sensor is reduced |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20150118638A (en) * | 2014-04-14 | 2015-10-23 | 에스케이하이닉스 주식회사 | Image sensor and method for manufacturing the same |
-
2019
- 2019-05-17 CN CN201910412522.5A patent/CN110112162B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102332457A (en) * | 2011-01-21 | 2012-01-25 | 香港应用科技研究院有限公司 | High ligh efficiency cmos image sensor |
| CN103378112A (en) * | 2012-04-26 | 2013-10-30 | 台湾积体电路制造股份有限公司 | Image sensor device and method |
| CN106169488A (en) * | 2015-05-22 | 2016-11-30 | 台湾积体电路制造股份有限公司 | The vertical transitions grid structure of backside illumination (BSI) complementary metal oxide semiconductors (CMOS) (CMOS) imageing sensor for using global shutter to capture |
| CN108257985A (en) * | 2016-12-28 | 2018-07-06 | 三星电子株式会社 | Optical sensor |
| CN108695347A (en) * | 2017-04-03 | 2018-10-23 | 豪威科技股份有限公司 | The crosstalk of high dynamic range image sensor is reduced |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110112162A (en) | 2019-08-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107039468B (en) | Image sensor and manufacturing method thereof | |
| KR101688084B1 (en) | An image sensor and package comprising the same | |
| US7883926B2 (en) | Methods for fabricating image sensor devices | |
| JP5745760B2 (en) | Image sensor element | |
| US11152415B2 (en) | Image sensor with separation pattern and image sensor module including the same | |
| US20060231898A1 (en) | CMOS image sensor and method of manufacturing the same | |
| TWI525804B (en) | Image sensor device and method of fabricating the same | |
| US11670661B2 (en) | Image sensor and method of fabricating same | |
| CN110890389A (en) | Image sensor and method for manufacturing the same | |
| US11133342B2 (en) | Image sensor | |
| US20200344433A1 (en) | Image sensor | |
| US11335726B2 (en) | Lens structure configured to increase quantum efficiency of image sensor | |
| KR102652444B1 (en) | Image sensor | |
| US20230057857A1 (en) | Image sensor including a light blocking film | |
| US7884400B2 (en) | Image device and method of fabricating the same | |
| CN110112162B (en) | Image sensor and forming method thereof | |
| TWI782461B (en) | Back-side illuminated image sensor and manufacturing method thereof | |
| CN108807447B (en) | Image sensor and forming method thereof | |
| KR102126061B1 (en) | An image sensor and method of fabricating the same | |
| CN115513230A (en) | Image sensor and manufacturing method thereof | |
| KR102420729B1 (en) | Lens structure configured to increase quantum efficiency of image sensor | |
| US20230136919A1 (en) | Image sensor and method of fabricating the same | |
| US20240290812A1 (en) | Image sensor | |
| TW202312473A (en) | Image sensor | |
| CN117316962A (en) | Image sensor and method of forming the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20221223 Address after: 223001 Room 318, Building 6, east of Zhenda Steel Pipe Company, south of Qianjiang Road, Huaiyin District, Huai'an City, Jiangsu Province Patentee after: Huaian Xide Industrial Design Co.,Ltd. Address before: No. 599, East Changjiang Road, Huaiyin District, Huai'an City, Jiangsu Province Patentee before: HUAIAN IMAGING DEVICE MANUFACTURER Corp. |
|
| TR01 | Transfer of patent right |