CN110400816A - Imaging sensor and forming method thereof - Google Patents
Imaging sensor and forming method thereof Download PDFInfo
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- CN110400816A CN110400816A CN201910754167.XA CN201910754167A CN110400816A CN 110400816 A CN110400816 A CN 110400816A CN 201910754167 A CN201910754167 A CN 201910754167A CN 110400816 A CN110400816 A CN 110400816A
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- convex lens
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- 238000000034 method Methods 0.000 title claims abstract description 44
- 238000003384 imaging method Methods 0.000 title claims abstract description 36
- 239000000758 substrate Substances 0.000 claims abstract description 64
- 239000004065 semiconductor Substances 0.000 claims abstract description 60
- 239000000463 material Substances 0.000 claims description 89
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical group [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 claims description 30
- 229910001935 vanadium oxide Inorganic materials 0.000 claims description 30
- 239000010410 layer Substances 0.000 claims description 26
- 229910052793 cadmium Inorganic materials 0.000 claims description 25
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 25
- 230000003647 oxidation Effects 0.000 claims description 23
- 238000007254 oxidation reaction Methods 0.000 claims description 23
- 238000005240 physical vapour deposition Methods 0.000 claims description 22
- 239000011241 protective layer Substances 0.000 claims description 22
- 238000000151 deposition Methods 0.000 claims description 20
- 230000008021 deposition Effects 0.000 claims description 20
- 229910052720 vanadium Inorganic materials 0.000 claims description 16
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 16
- CXKCTMHTOKXKQT-UHFFFAOYSA-N cadmium oxide Inorganic materials [Cd]=O CXKCTMHTOKXKQT-UHFFFAOYSA-N 0.000 claims description 8
- CFEAAQFZALKQPA-UHFFFAOYSA-N cadmium(2+);oxygen(2-) Chemical group [O-2].[Cd+2] CFEAAQFZALKQPA-UHFFFAOYSA-N 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 abstract description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 4
- 239000013077 target material Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000000149 penetrating effect Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- -1 argon ion Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 229910052732 germanium Inorganic materials 0.000 description 2
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000005516 deep trap Effects 0.000 description 1
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 239000007943 implant Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 230000001795 light effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000005622 photoelectricity Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Classifications
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- 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
- H01L27/14627—Microlenses
-
- 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
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- 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
A kind of imaging sensor and forming method thereof, described image sensor includes: semiconductor substrate；Convex lens, positioned at the surface of the semiconductor substrate；Convex lens curved-surface structure, positioned at the surface of the convex lens；Wherein, the upper surface Yu lower surface of the convex lens curved-surface structure are curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface；The upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, and the lower surface of the convex lens curved-surface structure is the surface of the neighbouring semiconductor substrate.The present invention program advantageously reduces light crosstalk, and improves the efficiency of photoelectric conversion.
Description
Technical field
The present invention relates to technical field of manufacturing semiconductors more particularly to a kind of imaging sensor and forming method thereof.
Background technique
Imaging sensor is the core component of picture pick-up device, realizes image taking function by converting optical signals into electric signal
Energy.By taking cmos image sensor (CMOS Image Sensors, CIS) device as an example, since it is with low-power consumption and high noise
Than the advantages of, therefore be widely applied in various fields.
By taking back-illuminated type (Back-side Illumination, BSI) CIS as an example, in existing manufacturing process, first half
Logical device, pixel device are formed in conductor substrate and forms metal interconnection structure on the surface of semiconductor substrate, are then adopted
Be bonded with the front of carrying wafer and the semiconductor substrate, so the back of semiconductor substrate is carried out it is thinned, and then partly
The back side of conductor substrate forms the subsequent technique of CIS, such as is formed at the semiconductor substrate back side of the pixel device latticed
Grid (Grid), filter (Color Filter) matrix is formed in the grid between the grid, in the table of filter
Face forms lens (Micro-lens) structure etc..
In the manufacturing process of (Front-side Illumination, FSI) CIS front-illuminated, it is also desirable to first in semiconductor
Logical device, pixel device are formed in substrate and forms metal interconnection structure on the surface of semiconductor substrate, then described
The surface of metal interconnection structure forms latticed grid, forms color filter matrix in the grid between the grid, is filtering
The surface of Look mirror forms lens arrangement etc..
However, in the prior art, optical crosstalk problem is still to be improved.
Summary of the invention
The technical problem to be solved by the present invention is to provide a kind of imaging sensors and forming method thereof, advantageously reduce light string
It disturbs, and improves the efficiency of photoelectric conversion.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of imaging sensor, comprising: semiconductor substrate；It is convex
Lens, positioned at the surface of the semiconductor substrate；Convex lens curved-surface structure, positioned at the surface of the convex lens；Wherein, the convex lens
The upper surface and lower surface of curved-surface structure are curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface；
The upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, and the lower surface of the convex lens curved-surface structure is
The surface of the neighbouring semiconductor substrate.
Optionally, the convex lens curved-surface structure includes multiple subsurface structures；Wherein, the subsurface structure is further away from institute
The surface of semiconductor substrate is stated, the refractive index of material is smaller；The refractive index of the material of the convex lens is more than or equal to any one
The refractive index of a sub- curved-surface structure；The upper surface of each subsurface structure and lower surface are curved surface, and the song of the upper surface
Rate radius is less than the radius of curvature of lower surface.
Optionally, the convex lens curved-surface structure includes two sub- curved-surface structures；The material of first subsurface structure is oxidation
Vanadium；And/or second subsurface structure material be cadmium oxide；Wherein, it is bent to be located at first son for the second subsurface structure
The surface of face structure.
Optionally, the imaging sensor further include: protective layer, positioned at the surface of the convex lens curved-surface structure；Wherein,
The refractive index of the material of the protective layer is less than or equal to the refractive index of any one subsurface structure.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of forming method of imaging sensor, comprising: provide
Semiconductor substrate；Convex lens is formed on the surface of the semiconductor substrate；Convex lens curved surface knot is formed on the surface of the convex lens
Structure；Wherein, under the upper surface Yu lower surface of the convex lens curved-surface structure are curved surface, and the radius of curvature of the upper surface is less than
The radius of curvature on surface；The upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, and the convex lens is bent
The lower surface of face structure is the surface of the neighbouring semiconductor substrate.
Optionally, the convex lens curved-surface structure includes multiple subsurface structures；Convex lens is formed on the surface of the convex lens
Curved-surface structure includes: to sequentially form multiple subsurface structures on the surface of the convex lens；Wherein, it is served as a contrast further away from the semiconductor
The refractive index on the surface at bottom, the material of the subsurface structure is smaller；The refractive index of the material of the convex lens, which is more than or equal to, appoints
The refractive index of one sub- curved-surface structure of meaning；The upper surface of each subsurface structure and lower surface are curved surface, and the upper surface
Radius of curvature be less than lower surface radius of curvature.
Optionally, the convex lens curved-surface structure includes two sub- curved-surface structures；It is sequentially formed on the surface of the convex lens
Multiple subsurface structures include: to form the first subsurface structure using vanadium oxide material；And/or it is formed using oxidation cadmium material
Second subsurface structure；Wherein, the second subsurface structure is located at the surface of the first subsurface structure.
Optionally, using vanadium oxide material formed the first subsurface structure include: using physical gas-phase deposition,
In the surface deposited oxide vanadium material of the convex lens, to form the first subsurface structure.
It optionally, include: to vanadium in the surface deposited oxide vanadium material of the convex lens using physical gas-phase deposition
Target carries out oxidation processes, to obtain vanadium oxide layer；Using physical gas-phase deposition, the vanadium oxide layer is bombarded,
To deposit the vanadium oxide material on the surface of the convex lens.
Optionally, using vanadium oxide material formed the second subsurface structure include: using physical gas-phase deposition,
In the surface deposited oxide cadmium material of the first subsurface structure, to form the second subsurface structure.
Optionally, using physical gas-phase deposition, in the surface deposited oxide cadmium material of the first subsurface structure
It include: that oxidation processes are carried out to cadmium target, to obtain cdo layer；Using physical gas-phase deposition, to the cdo layer
It is bombarded, to deposit the oxidation cadmium material on the surface of the convex lens.
Optionally, the forming method of the imaging sensor further include: formed on the surface of the convex lens curved-surface structure
Protective layer；Wherein, the refractive index of the material of the protective layer is less than or equal to the refractive index of any one subsurface structure.
Compared with prior art, the technical solution of the embodiment of the present invention has the advantages that
In embodiments of the present invention, by the way that convex lens curved-surface structure, and the upper surface and lower surface of convex lens curved-surface structure is arranged
It is curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface, can incident light be reflected, no
Incident light rays with angle are gathered, so that the incident light of more perspective incidence has an opportunity to penetrate convex lens, in turn
It is absorbed by photodiode, advantageously reduces light crosstalk, and improve the efficiency of photoelectric conversion；Further, from protective layer
Refractive index to convex lens successively increases, and helps to reduce light in the reflection of two media interface, improves the effect of photoelectric conversion
Rate.
Further, in the present invention is implemented, convex lens curved-surface structure includes multiple subsurface structures, and between subsurface structure
It can have different refractive index, and the subsurface structure is further away from the surface of the semiconductor substrate, the refraction of material
Rate is smaller, so that light has an opportunity when penetrating subsurface structure by multi-focusing, light is further gathered, is conducive to
Light crosstalk is further decreased, and improves the efficiency of photoelectric conversion.
Further, in embodiments of the present invention, convex lens curved-surface structure includes two sub- curved-surface structures, and the first subsurface knot
The material of structure is vanadium oxide, and/or, the material of the second subsurface structure is cadmium oxide, since the refractive index of vanadium oxide is greater than oxygen
The effect that light is further gathered may be implemented in the refractive index of cadmium.
Further, in embodiments of the present invention, oxygen is deposited on the surface of the convex lens using physical gas-phase deposition
Change vanadium material helps to make table on convex lens curved-surface structure self-assembling formation since PVD process has the characteristics that step coverage is poor
Face and lower surface are curved surface, and the radius of curvature of the upper surface is less than the pattern of the radius of curvature of lower surface.Further,
Since PVD process has the characteristics that non high temperature processing, facilitate in forming convex lens curved-surface structure, the pattern of convex lens is carried out
Protection.
Further, imaging sensor further includes protective layer, and the refractive index of the material of protective layer is less than or equal to any one
The refractive index of subsurface structure by the way that the smaller protective layer of refractive index is arranged, helps so that light in embodiments of the present invention
During passing through protective layer, convex lens curved-surface structure and convex lens, have an opportunity all to focus on each interface, light
It is able to repeatedly be gathered, is conducive to further decrease light crosstalk, and improve the efficiency of photoelectric conversion.
Detailed description of the invention
Fig. 1 is a kind of device profile structural schematic diagram of imaging sensor in the prior art；
Fig. 2 is a kind of flow chart of the forming method of imaging sensor in the embodiment of the present invention；
Fig. 3 to Fig. 7 is that the corresponding device of each step cuts open in a kind of forming method of imaging sensor in the embodiment of the present invention
Face structural schematic diagram；
Fig. 8 is a kind of input path schematic diagram of convex lens curved-surface structure in the embodiment of the present invention.
Specific embodiment
In existing image sensor technologies, optical signal reaches lens arrangement by lens module and is focused, then
Independent pixel (for example including photodiode) is reached after filtering by filter carries out photoelectric conversion.Wherein, when lens arrangement is caught
After grasping incident light, by filter structured filter, irrelevant light is removed, forms monochromatic light, incident photon reaches semiconductor lining
Bottom is absorbed by pixel device, photo-generated carrier is generated, to export electric signal.However in the prior art, optical crosstalk problem is still
It is so to be improved.
Referring to Fig.1, Fig. 1 is a kind of device profile structural schematic diagram of imaging sensor in the prior art.
In existing imaging sensor, semiconductor substrate 100 can be provided, is formed on the surface of semiconductor substrate 100
Cell structure 104, and then filter is formed in the opening between cell structure 104, and then in the surface shape of the filter
At lens arrangement 108.
Wherein, logical device, pixel device and metal interconnection structure, institute are formed in the semiconductor substrate 100
Stating pixel device can wrap containing photodiode 102.
Wherein, the filter may include the monochromatic filter of multiple color, for example, monochromatic light filter, can be with
For infrared ray filter, ultraviolet filter mirror etc..
The filter 111 and the filter 121 can be identical, can be with difference.
The route a and route b shown referring to Fig.1, when light is slanted through filter 111, may be staggered two pole of photoelectricity
102 position of pipe, leads to not absorb, or even propagates to adjacent photodiode 102；Or when light is from filter 121
When fringe region is injected, photodiode 102 may be avoided, leads to not absorb, influences image quality.
The present inventor has found after study, in the prior art, compared to the external environment that need to be detected, pixel list
Elemental size is minimum, causes the lens arrangement focusing light effect of imaging sensor limited, and light can not only enter after filter filters
It is mapped to the photosensitive region of respective pixel, can also enter adjacent pixel, so as to cause crosstalk, and reduce the effective photosensitive of photosensitive region
Efficiency.
In embodiments of the present invention, by the way that convex lens curved-surface structure, and the upper surface and lower surface of convex lens curved-surface structure is arranged
It is curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface, can incident light be reflected, no
Incident light rays with angle are gathered, so that the incident light of more perspective incidence has an opportunity to penetrate convex lens, in turn
It is absorbed by photodiode, advantageously reduces light crosstalk, and improve the efficiency of photoelectric conversion.
It is understandable to enable above-mentioned purpose of the invention, feature and beneficial effect to become apparent, with reference to the accompanying drawing to this
The specific embodiment of invention is described in detail.
Referring to Fig. 2, Fig. 2 is a kind of flow chart of the forming method of imaging sensor in the embodiment of the present invention.Described image
The forming method of sensor may include step S21 to step S23:
Step S21: semiconductor substrate is provided；
Step S22: convex lens is formed on the surface of the semiconductor substrate；
Step S23: the convex lens surface formed convex lens curved-surface structure, wherein the convex lens curved-surface structure it is upper
Surface and lower surface are curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface；
Wherein, the upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, the convex lens curved surface
The lower surface of structure is the surface of the neighbouring semiconductor substrate.
Above-mentioned each step is illustrated below in conjunction with Fig. 3 to Fig. 7.
Fig. 3 to Fig. 7 is that the corresponding device of each step cuts open in a kind of forming method of imaging sensor in the embodiment of the present invention
Face structural schematic diagram.
Referring to Fig. 3, semiconductor substrate 200 is provided, can have photodiode 202, In in the semiconductor substrate 200
The surface of the semiconductor substrate 200 can form anti-reflection layer 203.
Further, latticed cell structure 204 can be formed on the surface of the anti-reflection layer 203, and then in institute
It states and forms filter in the opening of cell structure 204.
The filter may include filter 211 and filter 221, and the filter 211 and filter 221 are suitable
Color can be identical or different.
In specific implementation, the semiconductor substrate 200 can be silicon substrate or the material of the semiconductor substrate 200
Material can also be the materials appropriate applied to imaging sensor such as germanium, SiGe, silicon carbide, GaAs or gallium indium, described
Semiconductor substrate 200 can also have outside for the silicon substrate of insulator surface or the germanium substrate of insulator surface, or growth
Prolong the substrate of layer (Epitaxy layer, Epi layer).Preferably, the semiconductor substrate 200 can be half be lightly doped
Conductor substrate, and doping type is opposite with drain region.Specifically, can by the semiconductor substrate 200 carry out ion implanting,
Realize deep trap doping (Deep Well Implant).
It should be pointed out that could be formed with logical device and pixel device, the picture in the semiconductor substrate 200
Plain device can wrap containing photodiode 202.
Specifically, the photodiode 202 can generate photoproduction current-carrying in the case where being excited by extraneous light intensity
Son, i.e. electronics.The photodiode 202 can be formed by ion implantation technology, moreover, passing through the energy of control ion implanting
Amount and concentration can control the depth and injection range of ion implanting, to control the depth and thickness of photodiode 202.
It should be pointed out that the mode that the photodiode 202 generallys use ion implanting is formed.
As a unrestricted example, in a kind of concrete application, the refractive index n=of the photodiode 202
3.4。
The logical device may include the device of the transistors such as gate structure and source and drain doping area.It may be noted that
Be, in embodiments of the present invention, for specific logical device composition with no restriction.
The pixel device may include photodiode 202 and pixel circuit, wherein the pixel circuit can wrap
It includes to form selection transistor, reset transistor and source with the device of the various transistors appropriate such as transistor, such as can wrap
Include transmission grid (Transfer Gate, TG) and floating diffusion region (Floating Diffusion, FD).It may be noted that
Be, in embodiments of the present invention, for specific pixel circuit composition with no restriction.
Wherein, the anti-reflection layer 203 can be silicon nitride layer.
As a unrestricted example, in a kind of concrete application, the refractive index n=of the anti-reflection layer 203
2.25。
The material of the cell structure 204 can be metal.
Referring to Fig. 4, convex lens 231 is formed on the surface of the filter.
Specifically, the convex lens 231 can be formed using any suitable mode, for example, with same or similar technique
Used in convex lens material it is identical, size is consistent.
As a unrestricted example, in a kind of concrete application, the convex lens 231 can use resin material
It is formed, refractive index n=1.71.
Referring to Fig. 5, the first subsurface structure 232 is formed on the surface of the convex lens 231.Wherein, first son is bent
The upper surface and lower surface of face structure 232 are curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface.
Wherein, the upper surface of the first subsurface structure 232 is the surface far from the semiconductor substrate 200, described
The lower surface of first subsurface structure 232 is the surface of the neighbouring semiconductor substrate 200
Further, the first subsurface structure 232 can use vanadium oxide (V2O5) material formed.
Specifically, the refractive index n=1.54 of existing a kind of regular oxidation vanadium material, for most of convex lens 231
Material can satisfy demand of its refractive index greater than the refractive index of the first subsurface structure 232.
Further, the step of forming the first subsurface structure 232 using vanadium oxide material may include: using object
Physical vapor deposition (Physical Vapor Deposition, PVD) technique, in the surface deposited oxide vanadium material of the convex lens
Material, to form the first subsurface structure 232.
Specifically, it by using the mode of PVD, can use the characteristic of PVD deposition step coverage difference, reduce channel side
Wall deposition particle, contribute to form upper surface radius of curvature be less than lower surface radius of curvature subsurface structure.
In specific implementation, it can be initially formed vanadium oxide material, PVD process is then directlyed adopt and vanadium oxide material is carried out
Bombardment, can also provide vanadium target, then form vanadium oxide material by field oxidation.
In latter specific embodiment, using physical gas-phase deposition, oxygen is deposited on the surface of the convex lens
The step of changing vanadium material may include: to carry out oxidation processes to vanadium target, to obtain vanadium oxide layer；Using physical vapour deposition (PVD) work
Skill bombards the vanadium oxide layer, to deposit the vanadium oxide material on the surface of the convex lens.
Specifically, ionization, then oxidation processes vanadium target material surface, then the oxygen to target material surface first can be carried out to oxygen atom
Change vanadium to be bombarded, so that vanadium oxide material is deposited to 231 surface of convex lens, to form the first subsurface structure 232.
Further, using physical gas-phase deposition, the step of bombarding the vanadium oxide layer, may include:
The vanadium oxide layer is bombarded using inert gas ion.
In a specific embodiment, vanadium oxide layer can be bombarded using argon ion, to be deposited improving
While efficiency, the damage to sedimentary is reduced.
In embodiments of the present invention, using physical gas-phase deposition the convex lens 231 surface deposited oxide vanadium
Material, since PVD process has the characteristics that step coverage is poor, help to make convex lens curved-surface structure self-assembling formation upper surface with
Lower surface is curved surface, and the radius of curvature of the upper surface is less than the pattern of the radius of curvature of lower surface.Further, due to
PVD process has the characteristics that non high temperature processing, facilitates in forming convex lens curved-surface structure, protects to the pattern of convex lens
Shield.
Referring to Fig. 6, the second subsurface structure 233 is formed on the surface of the first subsurface structure 232.Wherein, described
The upper surface and lower surface of second subsurface structure 233 are curved surface, and the radius of curvature of the upper surface is less than lower surface
Radius of curvature.
Wherein, refraction of the refractive index of the material of the second subsurface structure 233 less than the material of the first subsurface structure 232
Rate.
Wherein, the upper surface of the second subsurface structure 233 is the surface far from the semiconductor substrate 200, described
The lower surface of second subsurface structure 233 is the surface of the neighbouring semiconductor substrate 200.
Further, the second subsurface structure 233 can be formed using cadmium oxide (CdO) material.
Specifically, the refractive index n=1.49 of existing a kind of regular oxidation cadmium material, for the first subsurface structure 232
Material use vanadium oxide the case where, can satisfy its refractive index greater than the second subsurface structure 233 refractive index demand.
Further, the step of forming the second subsurface structure 233 using oxidation cadmium material may include: using object
Physical vapor deposition technique, it is bent to form second son in the surface deposited oxide cadmium material of the first subsurface structure 232
Face structure 233.
Specifically, it by using the mode of PVD, can use the characteristic of PVD deposition step coverage difference, reduce channel side
Wall deposition particle, contribute to form upper surface radius of curvature be less than lower surface radius of curvature subsurface structure.
In specific implementation, it can be initially formed oxidation cadmium material, PVD process is then directlyed adopt and oxidation cadmium material is carried out
Bombardment, can also provide cadmium target, then form oxidation cadmium material by field oxidation.
In latter specific embodiment, using physical gas-phase deposition, oxygen is deposited on the surface of the convex lens
The step of cadmium material may include: to carry out oxidation processes to cadmium target, to obtain cdo layer；Using physical vapour deposition (PVD) work
Skill bombards the cdo layer, to deposit the oxidation cadmium material on the surface of the convex lens.
Specifically, ionization, then oxidation processes cadmium target material surface, then the oxygen to target material surface first can be carried out to oxygen atom
Cadmium is bombarded, and so that oxidation cadmium material is deposited to 232 surface of the first subsurface structure, to form the second subsurface knot
Structure 233.
Further, using physical gas-phase deposition, the step of bombarding the cdo layer, may include:
The cdo layer is bombarded using inert gas ion.
In a specific embodiment, cdo layer can be bombarded using argon ion, to be deposited improving
While efficiency, the damage to sedimentary is reduced.
In embodiments of the present invention, convex lens curved-surface structure includes two sub- curved-surface structures, and the material of the first subsurface structure
Material 232 is vanadium oxide, and/or, the material of the second subsurface structure 233 is cadmium oxide, since the refractive index of vanadium oxide is greater than oxygen
The effect that light is further gathered may be implemented in the refractive index of cadmium.
In embodiments of the present invention, convex lens 231 can be initially formed using common process, re-forms convex lens curved-surface structure
230, the formation process of convex lens curved-surface structure 230 can also be used, is formed comprising the multilayer curved-surface structure including convex lens.
It should be pointed out that although the imaging sensor shown in Fig. 6 includes that two sons are bent using the convex lens curved-surface structure
It is described for the structure of face namely the convex lens curved-surface structure 230 includes the material 232 and the of the first subsurface structure
Two subsurface structures 233, however in embodiments of the present invention, for the number for the subsurface structure that convex lens curved-surface structure 230 includes
Amount is with no restrictions.
It is understood that further away from the surface of the semiconductor substrate 200, the refraction of the material of the subsurface structure
Rate is smaller, and the refractive index of the material of the convex lens 231 is more than or equal to the refractive index of any one subsurface structure.
In the present invention is implemented, convex lens curved-surface structure 230 includes multiple subsurface structures, and can be between subsurface structure
With different refractive index, and the subsurface structure, further away from the surface of the semiconductor substrate, the refractive index of material is got over
Small, so that light has an opportunity when penetrating subsurface structure by multi-focusing, light is further gathered, and is conducive into one
Step reduces light crosstalk, and improves the efficiency of photoelectric conversion.
Referring to Fig. 7, protective layer 270 is formed on the surface of the convex lens curved-surface structure 230；Wherein, the protective layer 270
The refractive index of material is less than or equal to the refractive index of any one subsurface structure.
As a unrestricted example, the protective layer 270 can be formed using silica material.
Specifically, the refractive index n=1.45 of existing a kind of regular oxidation silicon materials, for the second subsurface structure 233
Material use cadmium oxide the case where, can satisfy its refractive index greater than the protective layer 270 refractive index demand.
It is possible to further use low temperature chemical vapor deposition (Low Temperature Chemical Vapor
Deposition, LTCVD) technique forms the protective layer.Since LTCVD technique has the characteristics that non high temperature processing, facilitate
In forming convex lens curved-surface structure 230, the pattern of convex lens is protected.
In embodiments of the present invention, by the way that the smaller protective layer 270 of refractive index is arranged, help so that light is passing through guarantor
During sheath 270, convex lens curved-surface structure 230 and convex lens 231, have an opportunity all to focus on each interface, light
Line is able to repeatedly be gathered, and is conducive to further decrease light crosstalk, and improve the efficiency of photoelectric conversion.
Route c and route d referring to shown in Fig. 7, by repeatedly reflecting, make incidence when light is slanted through filter 211
The angle of light is gathered, and has an opportunity to be incident upon 202 position of photodiode, increases and absorbs chance, thus reduce propagate to it is adjacent
A possibility that photodiode 202；Or when light is injected from the fringe region of filter 221, by repeatedly reflecting, make into
The angle for penetrating light is gathered, and has an opportunity to be incident upon 202 position of photodiode, increases and absorb chance, improves image quality.
In embodiments of the present invention, by be arranged convex lens curved-surface structure 230, and the upper surface of convex lens curved-surface structure 230 with
Lower surface is curved surface, and the radius of curvature of the upper surface is less than the radius of curvature of lower surface, can make incident light
Refraction, the incident light rays of different angle are gathered, so that the incident light of more perspective incidence has an opportunity to penetrate convex lens
Mirror 231, and then absorbed by photodiode, light crosstalk is advantageously reduced, and improve the efficiency of photoelectric conversion；Further
Ground, the refractive index from protective layer 270 to convex lens 231 successively increase, facilitate reduce light two media interface reflection,
Improve the efficiency of photoelectric conversion.
Fig. 8 is a kind of input path schematic diagram of convex lens curved-surface structure in the embodiment of the present invention.
As seen from the figure, successively from the second subsurface structure 233, the refractive index of the first subsurface structure 232 to convex lens 231
Increase, helps to gather light, and reduce light in the reflection of each dielectric interface, improve the efficiency of photoelectric conversion, make
The incident light for obtaining more perspective incidence has an opportunity to be absorbed by photodiode 202.
The embodiment of the invention also discloses a kind of imaging sensors, as shown in fig. 6, may include: semiconductor substrate 200；
Convex lens 231, positioned at the surface of the semiconductor substrate 200；Convex lens curved-surface structure 230, positioned at the table of the convex lens 231
Face；Wherein, the upper surface Yu lower surface of the convex lens curved-surface structure 230 are curved surface, and the radius of curvature of the upper surface is small
Radius of curvature in lower surface；The upper surface of the convex lens curved-surface structure 230 is the surface far from the semiconductor substrate 200,
The lower surface of the convex lens curved-surface structure 230 is the surface of the neighbouring semiconductor substrate 200.
Further, the convex lens curved-surface structure 230 may include multiple subsurface structures；Wherein, the subsurface knot
For structure further away from the surface of the semiconductor substrate 200, the refractive index of material is smaller；The refraction of the material of the convex lens 231
Rate is more than or equal to the refractive index of any one subsurface structure；The upper surface and lower surface of each subsurface structure are curved surface,
And the radius of curvature of the upper surface is less than the radius of curvature of lower surface.
Further, the convex lens curved-surface structure 230 includes two sub- curved-surface structures；The material of first subsurface structure 231
Material is vanadium oxide；And/or second subsurface structure 232 material be cadmium oxide；Wherein, described 232, second subsurface structure
In the surface of the first subsurface structure 231.
Further, described image sensor can also include: protective layer 270, positioned at the convex lens curved-surface structure 230
Surface；Wherein, the refractive index of the material of the protective layer 270 is less than or equal to the refractive index of any one subsurface structure.
The pass above and shown in Fig. 1 to Fig. 4 is please referred to about the principle of the imaging sensor, specific implementation and beneficial effect
In the associated description of the forming method of imaging sensor, details are not described herein again.
Although present disclosure is as above, present invention is not limited to this.Anyone skilled in the art are not departing from this
It in the spirit and scope of invention, can make various changes or modifications, therefore protection scope of the present invention should be with claim institute
Subject to the range of restriction.
Claims (12)
1. a kind of imaging sensor characterized by comprising
Semiconductor substrate；
Convex lens, positioned at the surface of the semiconductor substrate；
Convex lens curved-surface structure, positioned at the surface of the convex lens；
Wherein, the upper surface Yu lower surface of the convex lens curved-surface structure are curved surface, and the radius of curvature of the upper surface is less than
The radius of curvature of lower surface；
The upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, the following table of the convex lens curved-surface structure
Face is the surface of the neighbouring semiconductor substrate.
2. imaging sensor according to claim 1, which is characterized in that the convex lens curved-surface structure includes multiple subsurfaces
Structure；
Wherein, for the subsurface structure further away from the surface of the semiconductor substrate, the refractive index of material is smaller；
The refractive index of the material of the convex lens is more than or equal to the refractive index of any one subsurface structure；
The upper surface and lower surface of each subsurface structure are curved surface, and the radius of curvature of the upper surface is less than lower surface
Radius of curvature.
3. imaging sensor according to claim 2, which is characterized in that the convex lens curved-surface structure includes two subsurfaces
Structure；
The material of first subsurface structure is vanadium oxide；
And/or
The material of second subsurface structure is cadmium oxide；
Wherein, the second subsurface structure is located at the surface of the first subsurface structure.
4. imaging sensor according to claim 2, which is characterized in that further include:
Protective layer, positioned at the surface of the convex lens curved-surface structure；
Wherein, the refractive index of the material of the protective layer is less than or equal to the refractive index of any one subsurface structure.
5. a kind of forming method of imaging sensor characterized by comprising
Semiconductor substrate is provided；
Convex lens is formed on the surface of the semiconductor substrate；
Convex lens curved-surface structure is formed on the surface of the convex lens；
Wherein, the upper surface Yu lower surface of the convex lens curved-surface structure are curved surface, and the radius of curvature of the upper surface is less than
The radius of curvature of lower surface；
The upper surface of the convex lens curved-surface structure is the surface far from the semiconductor substrate, the following table of the convex lens curved-surface structure
Face is the surface of the neighbouring semiconductor substrate.
6. the forming method of imaging sensor according to claim 5, which is characterized in that the convex lens curved-surface structure includes
Multiple subsurface structures；
Forming convex lens curved-surface structure on the surface of the convex lens includes:
Multiple subsurface structures are sequentially formed on the surface of the convex lens；
Wherein, further away from the surface of the semiconductor substrate, the refractive index of the material of the subsurface structure is smaller；
The refractive index of the material of the convex lens is more than or equal to the refractive index of any one subsurface structure；
The upper surface and lower surface of each subsurface structure are curved surface, and the radius of curvature of the upper surface is less than lower surface
Radius of curvature.
7. the forming method of imaging sensor according to claim 6, which is characterized in that the convex lens curved-surface structure includes
Two sub- curved-surface structures；
Sequentially forming multiple subsurface structures on the surface of the convex lens includes:
First subsurface structure is formed using vanadium oxide material；
And/or
Second subsurface structure is formed using oxidation cadmium material；
Wherein, the second subsurface structure is located at the surface of the first subsurface structure.
8. the forming method of imaging sensor according to claim 7, which is characterized in that form institute using vanadium oxide material
Stating the first subsurface structure includes:
It is bent to form first son in the surface deposited oxide vanadium material of the convex lens using physical gas-phase deposition
Face structure.
9. the forming method of imaging sensor according to claim 8, which is characterized in that use physical vapour deposition (PVD) work
Skill includes: in the surface deposited oxide vanadium material of the convex lens
Oxidation processes are carried out to vanadium target, to obtain vanadium oxide layer；
Using physical gas-phase deposition, the vanadium oxide layer is bombarded, described in being deposited on the surface of the convex lens
Vanadium oxide material.
10. the forming method of imaging sensor according to claim 7, which is characterized in that formed using vanadium oxide material
The second subsurface structure includes:
Using physical gas-phase deposition, in the surface deposited oxide cadmium material of the first subsurface structure, described in being formed
Second subsurface structure.
11. the forming method of imaging sensor according to claim 8, which is characterized in that use physical vapour deposition (PVD) work
Skill includes: in the surface deposited oxide cadmium material of the first subsurface structure
Oxidation processes are carried out to cadmium target, to obtain cdo layer；
Using physical gas-phase deposition, the cdo layer is bombarded, described in being deposited on the surface of the convex lens
Aoxidize cadmium material.
12. the forming method of imaging sensor according to claim 5, which is characterized in that further include:
Protective layer is formed on the surface of the convex lens curved-surface structure；
Wherein, the refractive index of the material of the protective layer is less than or equal to the refractive index of any one subsurface structure.
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| WO2023115774A1 (en) * | 2021-12-24 | 2023-06-29 | 长鑫存储技术有限公司 | Micro-lens assembly, photoelectric conversion device and manufacturing method, and imaging system |
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