CN108417595A - Imaging sensor and forming method thereof - Google Patents
Imaging sensor and forming method thereof Download PDFInfo
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- CN108417595A CN108417595A CN201810234161.5A CN201810234161A CN108417595A CN 108417595 A CN108417595 A CN 108417595A CN 201810234161 A CN201810234161 A CN 201810234161A CN 108417595 A CN108417595 A CN 108417595A
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- 238000000034 method Methods 0.000 title claims abstract description 74
- 238000003384 imaging method Methods 0.000 title claims abstract description 46
- 239000000758 substrate Substances 0.000 claims abstract description 56
- 239000004065 semiconductor Substances 0.000 claims abstract description 46
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 44
- 239000000463 material Substances 0.000 claims description 35
- 239000000377 silicon dioxide Substances 0.000 claims description 22
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 17
- 238000005516 engineering process Methods 0.000 claims description 16
- 238000001039 wet etching Methods 0.000 claims description 16
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 15
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 230000003287 optical effect Effects 0.000 abstract description 14
- 238000004519 manufacturing process Methods 0.000 abstract description 13
- 206010034972 Photosensitivity reaction Diseases 0.000 abstract description 6
- 230000036211 photosensitivity Effects 0.000 abstract description 6
- 239000010410 layer Substances 0.000 description 111
- 239000010408 film Substances 0.000 description 106
- 238000005530 etching Methods 0.000 description 10
- 239000007789 gas Substances 0.000 description 10
- 238000001035 drying Methods 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 238000001259 photo etching Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 230000000873 masking effect Effects 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 239000004020 conductor Substances 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 230000006378 damage Effects 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
- 239000012212 insulator Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 2
- 239000011241 protective layer Substances 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910052905 tridymite Inorganic materials 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
- 229910003978 SiClx Inorganic materials 0.000 description 1
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
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- 239000008358 core component Substances 0.000 description 1
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- 235000013399 edible fruits Nutrition 0.000 description 1
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- 229910052733 gallium Inorganic materials 0.000 description 1
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- 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
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
- H01L27/1462—Coatings
- H01L27/14621—Colour filter arrangements
-
- 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
- H01L27/1462—Coatings
- H01L27/14623—Optical shielding
-
- 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, the forming method includes：Semiconductor substrate is provided, the surface of the semiconductor substrate is formed with dielectric layer；Groove is formed in the dielectric layer, the opening of the groove is located at the dielectric layer surface；Dielectric film is formed, the dielectric film covers the dielectric layer and seals the opening of the groove, to form air gap；At least part for removing the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap, to form filter groove；Filter is formed in the filter groove.The present invention program can reduce production cost, avoid the formation of metallic pollution, reduce the loss of incident light, improve the photosensitivity of imaging sensor while preventing optical crosstalk.
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 technology
Imaging sensor is the core component of picture pick-up device, and image taking work(is realized 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.
For later illuminated (Back-side Illumination, BSI) CIS, in existing manufacturing process, first half
It includes photodiode that logical device, pixel device and metal interconnection structure, the pixel device are formed in conductor substrate,
Then it is bonded with the front of the semiconductor substrate using carrying wafer, and then the back of semiconductor substrate is thinned, into
And the subsequent technique of CIS is formed at the back side of semiconductor substrate, such as formed at the semiconductor substrate back side of the pixel device
Filter (Color Filter) matrix, lens (Microlens) structure etc..It is understood that in preceding illuminated (Front-side
Illumination, FSI) in CIS, filter, lens arrangement are respectively positioned on the front of semiconductor substrate.
In the image sensor, it after lens arrangement captures incident light, filters, removes irrelevant by filter array
Light forms monochromatic light, and incident photon reaches semiconductor substrate and absorbed by pixel device, generates photo-generated carrier.
Cause to influence imaging effect due to before light reaches silicon substrate, being easy to happen optical crosstalk, it is therefore desirable to half
The surface of conductor substrate forms metallic grid (Metal Grid) so that incident light is isolated.However in the prior art, metal is formed
The process is more complicated for grid, causes production cost higher, and is easy to form metallic pollution, and metallic grid also results in incident light
Loss, reduce the photosensitivity of imaging sensor.
Invention content
The technical problem to be solved by the present invention is to provide a kind of imaging sensors and forming method thereof, can prevent optics string
While disturbing, production cost is reduced, metallic pollution is avoided the formation of, reduces the loss of incident light, improve the photosensitive of imaging sensor
Perception.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of forming method of imaging sensor, including：It provides
The surface of semiconductor substrate, the semiconductor substrate is formed with dielectric layer；Groove is formed in the dielectric layer, the groove
Opening is located at the dielectric layer surface；Dielectric film is formed, the dielectric film covers the dielectric layer and seals the groove
Opening, to form air gap；Remove at least one of the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap
Part, to form filter groove；Filter is formed in the filter groove.
Optionally, the forming method of described image sensor further includes：Lens arrangement is formed on the surface of the filter.
Optionally, the material of the dielectric layer is selected from：Silica and silicon nitride.
Optionally, the material of the dielectric film is selected from：Silica and silicon nitride.
Optionally, the dielectric film is silica, and the formation dielectric film includes：Using SiH4Form the medium
Film.
Optionally, the material identical of the dielectric layer and the dielectric film, the medium removed between adjacent air gap
At least part of dielectric layer between film and adjacent air gap includes：Using dry etch process, removal adjacent air gap it
Between the dielectric film and adjacent air gap between the dielectric layer at least part.
Optionally, the dielectric layer is different from the material of the dielectric film, removes the dielectric film between adjacent air gap
And at least part of the dielectric layer between adjacent air gap includes：Using dry etch process, remove between adjacent air gap
Dielectric film；Using wet-etching technology, at least part of the dielectric layer between adjacent air gap is removed.
Optionally, at least part of the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap is removed
Including：The dielectric film is planarized, to expose the surface of the dielectric layer, and the medium retained at the top of the air gap is thin
Film；Using wet-etching technology, at least part of the dielectric layer between adjacent air gap is removed.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of imaging sensor, including：Semiconductor substrate, institute
The surface for stating semiconductor substrate is formed with dielectric layer；Groove is located in the dielectric layer；Dielectric film seals the groove
Opening has filter groove to form air gap in the dielectric layer between adjacent air gap；Filter is located in the filter groove.
Optionally, the filter covers the dielectric film at the top of the air gap.
Compared with prior art, the technical solution of the embodiment of the present invention has the advantages that：
In embodiments of the present invention, semiconductor substrate is provided, the surface of the semiconductor substrate is formed with dielectric layer；Institute
It states and forms groove in dielectric layer, the opening of the groove is located at the dielectric layer surface；Form dielectric film, the dielectric film
It covers the dielectric layer and seals the opening of the groove, to form air gap；Remove adjacent air gap between dielectric film and
At least part of dielectric layer between adjacent air gap, to form filter groove；Filter is formed in the filter groove.Using
Said program forms air gap by forming groove, and by forming dielectric film, air gap may be used to incident light in the trench
Be isolated, compared with the prior art in use metallic grid, can while preventing optical crosstalk, reduce production cost,
Metallic pollution is avoided the formation of, the loss of incident light is reduced, improves the photosensitivity of imaging sensor.
Further, in the material identical of the dielectric layer and the dielectric film, it may be used dry etch process, one
At least part of the dielectric layer between dielectric film and adjacent air gap between secondary property removal adjacent air gap, to form filter
Groove.Using the embodiment of the present invention, helps to reduce cost and reduce process complexity.
Further, in the material difference of the dielectric layer and the dielectric film, dry etch process may be used, go
Except the dielectric film between adjacent air gap, and then wet-etching technology is used, the dielectric layer between removal adjacent air gap is at least
A part, to form filter groove.Using the embodiment of the present invention, helps to use different dielectric materials, improve to air gap
Protection, and since dielectric layer is different from the material of the dielectric film, wet etching may be used when removing dielectric layer
Technique needs additional configuration mask layer compared to dry process etching and uses photoetching process, can be effectively reduced and be produced into
This.
Further, it is possible to planarize the dielectric film, to expose the surface of the dielectric layer, and retain the air gap
Top surface dielectric film, and then use wet-etching technology, remove at least one of dielectric layer between adjacent air gap
Point.Additional configuration mask layer is needed compared to dry process etching and uses photoetching process, using the embodiment of the present invention, by flat
Smooth chemical industry skill and wet-etching technology form air gap grid, it is possible to reduce twice masking layer process more efficiently reduces production
Cost.
Description of the drawings
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. 8 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. 9 to Figure 11 is the corresponding device of part steps in the forming method of another imaging sensor in the embodiment of the present invention
Part cross-sectional view；
Figure 12 to Figure 14 is that part steps are corresponding in the forming method of another imaging sensor in the embodiment of the present invention
Device profile structural schematic diagram.
Specific implementation mode
In the image sensor, it after lens arrangement captures incident light, filters, removes irrelevant by filter array
Light forms monochromatic light, and incident photon reaches semiconductor substrate and absorbed by pixel device, generates photo-generated carrier.Due to being arrived in light
Up to before silicon substrate, being easy to happen optical crosstalk causes to influence imaging effect, it is therefore desirable to be formed on the surface of semiconductor substrate
Metallic grid is to be isolated incident light.However in the prior art, it forms metallic grid the process is more complicated, lead to production cost
It is higher, and be easy to form metallic pollution, metallic grid also results in the loss of incident light, reduces the photaesthesia of imaging sensor
Property.
The present inventor passes through the study found that work as light injects gas by dielectric material (such as silica), and enters
When firing angle is more than predetermined angle, it may occur that total reflection is found after further study, if replacing metallic grid using air gap,
The energy loss of incident light is very low, or even is nearly free from loss in total reflection, and can also avoid the formation of metal dirt
Dye.
In embodiments of the present invention, semiconductor substrate is provided, the surface of the semiconductor substrate is formed with dielectric layer；Institute
It states and forms groove in dielectric layer, the opening of the groove is located at the dielectric layer surface；Form dielectric film, the dielectric film
It covers the dielectric layer and seals the opening of the groove, to form air gap；Remove adjacent air gap between dielectric film and
At least part of dielectric layer between adjacent air gap, to form filter groove；Filter is formed in the filter groove.Using
Said program forms air gap by forming groove, and by forming dielectric film, air gap may be used to incident light in the trench
Be isolated, compared with the prior art in use metallic grid, can while preventing optical crosstalk, reduce production cost,
Metallic pollution is avoided the formation of, the loss of incident light is reduced, improves the photosensitivity of imaging sensor.
It is understandable to enable above-mentioned purpose, feature and the advantageous effect of the present invention to become apparent, below in conjunction with the accompanying drawings to this
The specific embodiment of invention is described in detail.
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
Dielectric layer 101 forms metallic grid 104 on the surface of the dielectric layer 101, and then in the opening between metallic grid 104
Filter 106 is formed, and then lens arrangement 108 is formed on the surface of the filter 106.
Specifically, the metallic grid 104 avoids generation optical crosstalk from causing to influence imaging effect for stopping incident light
Fruit, the filter 106 can cover the top of the metallic grid 104, the top surface of the filter 106 can also with it is described
The top of metallic grid 104 flush or less than metallic grid 104 top.It is understood that setting filter 106 covers institute
The top for stating metallic grid 104 contributes to before forming lens arrangement 108 to provide more even curface basis, improves saturating
The quality of mirror structure 108.
However in the prior art, the process is more complicated for formation metallic grid 104, such as needs in semiconductor substrate
100 surface sequentially forms substrate protective layer, barrier layer, metal layer etc., patterns and etches the substrate protective layer, blocking
Layer, metal layer cause production cost higher, and be easy to form metallic pollution, metallic grid to form the metallic grid 104
104 also result in the loss of incident light, reduce the photosensitivity of imaging sensor.
With reference 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 S25：
Step S21：Semiconductor substrate is provided, the surface of the semiconductor substrate is formed with dielectric layer；
Step S22：Groove is formed in the dielectric layer, the opening of the groove is located at the dielectric layer surface；
Step S23：Dielectric film is formed, the dielectric film covers the dielectric layer and seals the opening of the groove,
To form air gap；
Step S24：Remove at least one of the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap
Point, to form filter groove；
Step S25：Filter is formed in the filter groove.
Above-mentioned each step is illustrated with reference to Fig. 3 to Fig. 8.
Fig. 3 to Fig. 8 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.
With reference to Fig. 3, semiconductor substrate 200 is provided, the surface of the semiconductor substrate 200 is formed with dielectric layer 201.
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).
Mutually link it should be pointed out that being formed with logical device, pixel device and metal in the semiconductor substrate 200
Structure, the pixel device include photodiode.
Wherein, the dielectric layer 201 can be used for protecting semiconductor substrate 200, avoid forming groove in the subsequent process
Injury is generated to semiconductor substrate 200 when 202, can be also used for surrounding the air gap formed in subsequent technique.The dielectric layer 201
Material can be selected from：Silica, silicon nitride or other materials appropriate.Wherein, the silica for example can be SiO2,
The silicon nitride for example can be Si3N4。
With reference to Fig. 4, groove 202 is formed in the dielectric layer 201, the opening of the groove 202 is located at the dielectric layer
201 surfaces.
Specifically, it is to cover that the technique for groove 202 being formed in the dielectric layer 201, which can be with patterned mask layer,
Film performs etching the dielectric layer 201 and the semiconductor substrate 200 to be formed.
Further, can be that dry method is carved to the technique that the dielectric layer 201 and the semiconductor substrate 200 perform etching
It loses (Dry Etch).
It is understood that the groove 202 is used to form air gap in the subsequent process, to prevent optical crosstalk, therefore
The depth of the groove 202 should not be excessively shallow, is otherwise difficult to realize prevent the effect of optical crosstalk；The depth of the groove 202
Should not be too deep, it is otherwise easy that semiconductor substrate is caused to damage, and if the thickness of dielectric layer 201 is blocked up and groove 202
Depth it is too deep, can also improve process complexity, increase cost.It in specific implementation, can be according in same or similar technique
The depth of metallic grid, is arranged the depth of the groove 202 so that the air gap formed in subsequent technique perpendicular to semiconductor
The depth of development length on the direction on the surface of substrate 200 close to metallic grid.
It is understood that the internal diameter of the groove 202 should not be excessive, excessive space is otherwise occupied, after reducing
The size of the continuous filter formed, and then reduce the quality of output image；The internal diameter of the groove 202 should not be too small, otherwise shape
At air gap it is very few, be not enough to reflect incident light.As a unrestricted example, the internal diameter of the groove 202
0.2 μm can be less than and be more than 5nm, for example, 50nm.
With reference to Fig. 5, dielectric film 203 is formed, the dielectric film 203 covers the dielectric layer 201 and seals the ditch
The opening of slot 202, to form air gap 204.
Specifically, the dielectric film 203 seals the opening of the groove 202, and sealing is sealed or approach to be formed
Chamber structure namely the air gap 204.It is understood that it is thin that medium will also be formed in the side wall of the groove 202 and bottom surface
Film 203.
Further, the dielectric film 203 is used for around air gap 204, to seal the gas in air gap 204 up for safekeeping, to
Incident light is reflected.The material of the dielectric film 203 can be selected from：Silica, silicon nitride or other materials appropriate
Material.Wherein, the silica for example can be SiO2, the silicon nitride for example can be Si3N4。
Preferably, when the dielectric film 203 is silica, silicon source gas SiH may be used4It is thin to form the medium
Film 203.Specifically, using SiH4Formed silica, Step Coverage performance is poor, overhang (Over-hanging) performance compared with
It is good, therefore 204 depth of air gap formed is deeper, helps to be better protected from optical crosstalk.
Further, when the dielectric film 203 is silica, the gas phase of plasma enhanced chemical may be used
Depositing operation (Plasma Enhanced Chemical Vapor Deposition, PECVD) forms the dielectric film 203,
Good with quality of forming film, pin hole is less, the advantages that not being easily cracked.
It should be pointed out that the environmental gas when gas type enclosed in the air gap 204 is by formation dielectric film 203
Type determines, can be air, oxygen (O2), nitrogen (N2) or other kinds of gas.Specifically, when the medium formed is thin
When film 203 is silica, the gas type enclosed in the air gap 204 can be oxygen；When the dielectric film 203 of formation is nitrogen
When SiClx, the gas type enclosed in the air gap 204 can be nitrogen.
With reference to Fig. 6, the dielectric layer between dielectric film 203 and the adjacent air gap 204 between adjacent air gap 204 is removed
201 at least part, to form filter groove 205.
Specifically, dry etch process may be used, remove the dielectric film 203 and phase between adjacent air gap 204
At least part of the dielectric layer 201 between adjacent air gap 204.
It should be pointed out that above-mentioned technique is suitable for dielectric film 203 and identical dry method may be used in dielectric layer 201
The case where etching technics removes in one of technique, for example, the dielectric layer 201 and the dielectric film 203 material identical,
The case where being silica or being silicon nitride.
In embodiments of the present invention, it when the material identical of the dielectric layer 201 and the dielectric film 203, can adopt
With dry etch process, Jie between the disposable dielectric film 203 removed between adjacent air gap 204 and adjacent air gap 204
At least part of matter layer 201, to form filter groove 205.Using the embodiment of the present invention, helps to reduce cost and reduce work
Skill complexity.
With reference to Fig. 7, filter 206 is formed in the filter groove 205.
Specifically, the filter 206 can cover the dielectric film 203 at 204 top of the air gap, the filter 206
Top surface can also be flushed with the top of the dielectric film 203 or less than dielectric film 203 top.It is appreciated that
That setting filter 206 covers the dielectric film 203 at the top of the air gap 204, contribute to before forming lens arrangement offer compared with
For even curface basis, the quality of lens arrangement is improved.Fig. 7 shows that the top surface of filter 206 is higher than the medium
The case where film 203 namely filter 206 cover the dielectric film 203.
With reference to Fig. 8, lens arrangement 208 is formed on the surface of the filter 206.
Specifically, it after lens arrangement 208 captures incident light, is filtered by filter 206, removes irrelevant light, formed
Monochromatic light, incident photon reach semiconductor substrate 200 and are absorbed by pixel device, generate photo-generated carrier.More specifically, incident
Light can penetrate lens arrangement 208, filter 206 and dielectric film 203 and inject air gap 204, can also penetrate lens arrangement
208, filter 206, dielectric layer 201 and dielectric film 203 inject air gap 204.
The correspondence of incident angle α, refraction angle and reflected energy is as shown in table 1.When incident light through lens arrangement 208,
When filter 206 and dielectric film 203 inject air gap 204, with the increase of incident angle α, refraction angle also accordingly increases, and reflects energy
Also correspondence is increased up 100% to amount.
As shown in Table 1, when incident angle α is more than 40 degree, it may occur that total reflection can be effectively prevented optical crosstalk.
Table 1
| Incidence angle | 0° | 30° | 39° | 39.3° | 40° | 50° | 60° |
| Refraction angle | 0° | 51° | 79° | 82° | 90° | ||
| Reflected energy | 4.70% | 6.80% | 36% | 47% | 100% | 100% | 100% |
In embodiments of the present invention, it by forming groove 202, and is formed in groove 202 by forming dielectric film 203
Air gap 204 may be used air gap 204 and incident light be isolated, compared with the prior art in use metallic grid, can be anti-
Only while optical crosstalk, production cost is reduced, metallic pollution is avoided the formation of, reduce the loss of incident light, improves image sensing
The photosensitivity of device.
In specific implementation, the dielectric layer 201 can be with difference with the material of the dielectric film 203.It is shown in Fig. 5
Imaging sensor in, forming dielectric film 203, the dielectric film 203 covers the dielectric layer 201 and seal the ditch
The opening of slot 202 can also use the dielectric film between other methods removal adjacent air gap 204 after forming air gap 204
At least part of dielectric layer 201 between 203 and adjacent air gap 204.
Fig. 9 to Figure 11 is the corresponding device of part steps in the forming method of another imaging sensor in the embodiment of the present invention
Part cross-sectional view.
With reference to Fig. 9, on the basis of the imaging sensor shown in Fig. 5, using dry etch process, adjacent air gap is removed
Dielectric film 203 between 204.
It should be pointed out that in specific implementation, dielectric film 203 is formed in the side wall of the groove 202 and bottom surface
It can be retained.
Wherein, the dielectric layer 201 can be different from the material of the dielectric film 203.Such as the dielectric layer 201
Material can be silica, and the material of the dielectric film 203 can be silicon nitride.
When light injects gas by silicon nitride material and incidence angle is more than 28.4 degree, it may occur that total reflection can prevent
Optical crosstalk.Compared to silica material, the dielectric film 203 uses silicon nitride, can be prevented within the scope of greater angle
Optical crosstalk, and the smaller that critical size can be done contribute to the area for reducing single pixel, increase semiconductor substrate 200
Utilization rate.
Referring to Fig.1 0, using wet-etching technology, at least part of the dielectric layer 203 between adjacent air gap 204 is removed,
To form filter groove 305.
In specific implementation, dry etch process can also be used, the dielectric layer 201 between adjacent air gap 204 is removed
At least partially, it to form filter groove 305, however uses dry process etching to need additional configuration mask layer and uses photoetching
Technique can reduce by one of masking layer process using wet-etching technology.
Referring to Fig.1 1, filter 306 is formed in the filter groove 305.
Specifically, the filter 306 can cover the dielectric film 203 at 204 top of the air gap, the filter 306
Top surface can also be flushed with the top of the dielectric film 203 or less than dielectric film 203 top.It is appreciated that
That setting filter 306 covers the dielectric film 203 at the top of the air gap 204, contribute to before forming lens arrangement offer compared with
For even curface basis, the quality of lens arrangement is improved.Figure 11 shows that the top surface of filter 306 is higher than the medium
The case where film 203 namely filter 306 cover the dielectric film 203.
In embodiments of the present invention, it when the material difference of the dielectric layer 201 and the dielectric film 203, can adopt
With dry etch process, the dielectric film 203 between adjacent air gap 204 is removed, and then use wet-etching technology, removal is adjacent
At least part of dielectric layer 201 between air gap 204, to form filter groove 305.Using the embodiment of the present invention, contribute to
Using different dielectric materials, the protection to air gap is improved.And due to dielectric layer 201 and the dielectric film 203
Material is different, and wet-etching technology may be used when removing dielectric layer 201, needs additional configuration to cover compared to dry process etching
Film layer (Mask) simultaneously uses photoetching process, it is possible to reduce one of masking layer process, to be effectively reduced production cost.
Figure 12 to Figure 14 is that part steps are corresponding in the forming method of another imaging sensor in the embodiment of the present invention
Device profile structural schematic diagram.
Referring to Fig.1 2, on the basis of the imaging sensor shown in Fig. 5, the dielectric film 203 is planarized (with reference to figure
5), to expose the surface of the dielectric layer 201, and retain the dielectric film 403 at 204 top of the air gap.
It should be pointed out that in specific implementation, dielectric film 203 is formed in the side wall of the groove 202 and bottom surface
It can be retained.
Wherein, the dielectric layer 201 can be different from the material of the dielectric film 203, therefore the dielectric layer 201
Top surface can be as the stop-layer (Stop-layer) of flatening process.Such as the material of the dielectric layer 201 can be
The material of silica, the dielectric film 203 can be silicon nitride.
In specific implementation, dry etch process can also be used to etch the dielectric film 203, is given an account of with exposing
The surface of matter layer 201, however use dry process etching to need additional configuration mask layer and use photoetching process, using planarization
It can reduce by one of masking layer process.
Referring to Fig.1 3, using wet-etching technology, at least part of the dielectric layer 201 between adjacent air gap 204 is removed,
To form filter groove 405.
In specific implementation, dry etch process can also be used, the dielectric layer 201 between adjacent air gap 204 is removed
At least partially, it to form filter groove 305, however uses dry process etching to need additional configuration mask layer and uses photoetching
Technique can reduce by one of masking layer process using wet-etching technology.
Referring to Fig.1 4, filter 406 is formed in the filter groove 405.
Specifically, the filter 406 can cover the dielectric film 403 at 204 top of the air gap, the filter 406
Top surface can also be flushed with the top of the dielectric film 403 at the top of the air gap 204 or less than dielectric film 403 top
Portion.It is understood that setting filter 406 covers the dielectric film 403 at 204 top of the air gap, help forming lens
More even curface basis is provided before structure, improves the quality of lens arrangement.Figure 14 shows the top table of filter 406
The case where face covers the dielectric film 403 higher than the dielectric film 403 namely filter 406.
In embodiments of the present invention, the dielectric film 203 (with reference to Fig. 5) can be planarized, to expose the medium
The surface of layer 201, and retain the dielectric film 403 of the top surface of the air gap 204, and then wet-etching technology is used, it goes
Except at least part of the dielectric layer 201 between adjacent air gap 204.Additional configuration mask layer is needed compared to dry process etching
And photoetching process is used, and using the embodiment of the present invention, air gap grid is formed by flatening process and wet-etching technology, it can be with
Twice masking layer process is reduced, production cost is more efficiently reduced.
In embodiments of the present invention, a kind of imaging sensor is also provided, with reference to Fig. 8, described image sensor may include：
The surface of semiconductor substrate 200, the semiconductor substrate 200 is formed with dielectric layer 201；
Groove 202 is located in the dielectric layer 201；
Dielectric film 203 seals the opening of the groove 202 to form air gap 204, the medium between adjacent air gap 204
There is filter groove 205 in layer 201；
Filter 206 is located in the filter groove 205.
It should be pointed out that can also have the medium on the side wall of groove 202 thin between the adjacent air gap 204
Between the dielectric film 203 that film 203 namely filter groove 205 can be between adjacent air gaps 204.Specifically, if
Remove at least part of of the dielectric layer 201 between dielectric film 203 and the adjacent air gap 204 between adjacent air gap 204
In the process, whole dielectric layers 201 are eliminated or eliminate the top half of dielectric layer 201, then air gap 204 and filter 206 it
Between with dielectric film 203 be isolated.
Further, the filter 206 can cover the dielectric film 203 at 204 top of the air gap.
Further, the material of the dielectric layer 201 can be selected from：Silica and silicon nitride.
Further, the material of the dielectric film 203 can be selected from：Silica and silicon nitride.The medium is thin
Film 203 can be identical with the material of the dielectric layer 201, can be with difference.
Further, the internal diameter of the groove 202 can be less than 0.2 μm.
It is please referred to above and shown in Fig. 2 to Figure 14 about the principle of the imaging sensor, specific implementation and advantageous effect
The associated description of forming method about imaging sensor, details are not described herein again.
Although present disclosure is as above, present invention is not limited to this.Any those 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 (10)
1. a kind of forming method of imaging sensor, which is characterized in that including：
Semiconductor substrate is provided, the surface of the semiconductor substrate is formed with dielectric layer；
Groove is formed in the dielectric layer, the opening of the groove is located at the dielectric layer surface；
Dielectric film is formed, the dielectric film covers the dielectric layer and seals the opening of the groove, to form air gap；
At least part for removing the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap, to form filter
Groove；
Filter is formed in the filter groove.
2. the forming method of imaging sensor according to claim 1, which is characterized in that further include：
Lens arrangement is formed on the surface of the filter.
3. the forming method of imaging sensor according to claim 1, which is characterized in that the material of the dielectric layer selects
From：Silica and silicon nitride.
4. the forming method of imaging sensor according to claim 1, which is characterized in that the material of the dielectric film selects
From：Silica and silicon nitride.
5. the forming method of imaging sensor according to claim 1, which is characterized in that the dielectric film is oxidation
Silicon, the formation dielectric film include：
Using SiH4Form the dielectric film.
6. the forming method of imaging sensor according to claim 1, which is characterized in that the dielectric layer and the medium
The material identical of film, it is described removal adjacent air gap between dielectric film and adjacent air gap between dielectric layer at least one
Part includes：
Using dry etch process, the dielectric film between adjacent air gap and the dielectric layer between adjacent air gap are removed
At least part.
7. the forming method of imaging sensor according to claim 1, which is characterized in that the dielectric layer and the medium
The material of film is different, removes at least part of the dielectric layer between dielectric film and the adjacent air gap between adjacent air gap
Including：
Using dry etch process, the dielectric film between adjacent air gap is removed；
Using wet-etching technology, at least part of the dielectric layer between adjacent air gap is removed.
8. the forming method of imaging sensor according to claim 1, which is characterized in that Jie between removal adjacent air gap
At least part of dielectric layer between matter film and adjacent air gap includes：
The dielectric film is planarized, to expose the surface of the dielectric layer, and retains the dielectric film at the top of the air gap；
Using wet-etching technology, at least part of the dielectric layer between adjacent air gap is removed.
9. a kind of imaging sensor, which is characterized in that including：
The surface of semiconductor substrate, the semiconductor substrate is formed with dielectric layer；
Groove is located in the dielectric layer；
Dielectric film seals the opening of the groove to form air gap, has filter groove in the dielectric layer between adjacent air gap；
Filter is located in the filter groove.
10. imaging sensor according to claim 9, which is characterized in that
The filter covers the dielectric film at the top of the air gap.
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