CN108321164A - Imaging sensor and forming method thereof - Google Patents
Imaging sensor and forming method thereof Download PDFInfo
- Publication number
- CN108321164A CN108321164A CN201810168637.XA CN201810168637A CN108321164A CN 108321164 A CN108321164 A CN 108321164A CN 201810168637 A CN201810168637 A CN 201810168637A CN 108321164 A CN108321164 A CN 108321164A
- Authority
- CN
- China
- Prior art keywords
- semiconductor substrate
- doped region
- back side
- photodiode
- imaging sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000003384 imaging method Methods 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims abstract description 37
- 239000000758 substrate Substances 0.000 claims abstract description 158
- 239000004065 semiconductor Substances 0.000 claims abstract description 152
- 238000011161 development Methods 0.000 claims description 17
- 230000005622 photoelectricity Effects 0.000 claims description 17
- 238000000137 annealing Methods 0.000 claims description 9
- 238000005224 laser annealing Methods 0.000 claims description 6
- 230000035945 sensitivity Effects 0.000 abstract description 11
- 150000002500 ions Chemical class 0.000 description 25
- 238000002955 isolation Methods 0.000 description 19
- 230000008569 process Effects 0.000 description 10
- 230000005540 biological transmission Effects 0.000 description 8
- 238000005520 cutting process Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- 230000031700 light absorption Effects 0.000 description 6
- 238000009792 diffusion process Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000005468 ion implantation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000003331 infrared imaging Methods 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000010586 diagram 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
- 239000012212 insulator Substances 0.000 description 2
- 238000004151 rapid thermal annealing Methods 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
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-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
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- HAYXDMNJJFVXCI-UHFFFAOYSA-N arsenic(5+) Chemical compound [As+5] HAYXDMNJJFVXCI-UHFFFAOYSA-N 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000002708 enhancing effect Effects 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
- 230000006872 improvement Effects 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
- 230000010354 integration Effects 0.000 description 1
- 238000004093 laser heating Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000000644 propagated effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011160 research Methods 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
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14643—Photodiode arrays; MOS imagers
- H01L27/14649—Infrared imagers
Abstract
A kind of imaging sensor and forming method thereof, the method includes：Semiconductor substrate is provided, the semiconductor substrate has front and back；The first ion implanting is carried out from the semiconductor substrate that just faces of the semiconductor substrate, to form front photodiode doped region；The second ion implanting is carried out to the semiconductor substrate from the back side of the semiconductor substrate, to form back side photodiode doped region, wherein the front photodiode doped region is connected to the back side photodiode doped region.The present invention program can improve the sensitivity of imaging sensor.
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 (Image Sensors) is the core component of picture pick-up device, by converting optical signals into telecommunications
Number realize image camera function.Since cmos image sensor (CMOS Image Sensor, CIS) has low-power consumption and high letter
Make an uproar than the advantages of, therefore be widely applied in various fields.
By taking infrared ray (Infrared Rays, IR) imaging sensor as an example, it can be captured by camera lens (Micro-lens)
To incident light, IR filters (Colour filter) or other devices is used to be filtered to incident light to remove irrelevant light, so
After make infrared photon reach photodiode region be absorbed, formed photoelectron.
However, existing infrared imaging sensor sensitivity is relatively low.Specifically, the depth due to photodiode is logical
It is often smaller, and the wavelength of infrared ray is usually longer (0.76um to 1000um), leads to the mistake that photodiode is passed through in infrared ray
Cheng Zhong, light absorption are very few, it is difficult to generate enough photoelectrons, cause sensitivity decrease.
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 improve image sensing
The sensitivity of device.
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
Semiconductor substrate, the semiconductor substrate have front and back；It is served as a contrast from the semiconductor that just faces of the semiconductor substrate
Bottom carries out the first ion implanting, to form front photodiode doped region；From the back side of the semiconductor substrate to described half
Conductor substrate carries out the second ion implanting, to form back side photodiode doped region, wherein the front photodiode is mixed
Miscellaneous area is connected to the back side photodiode doped region.
Optionally, development length of the front photodiode doped region on the thickness direction of the semiconductor substrate
It is 1 μm to 2.5 μm；And/or extension of the back side photodiode doped region on the thickness direction of the semiconductor substrate
Length is 1 μm to 2.5 μm.
Optionally, before carrying out the second ion implanting to the semiconductor substrate from the back side of the semiconductor substrate, institute
The forming method for stating imaging sensor further includes：The semiconductor substrate is carried out from the back side to be thinned to preset thickness.
Optionally, the preset thickness is 4 μm to 5 μm.
Optionally, further include after forming the back side photodiode doped region：To the back side photodiode
Doped region is annealed.
Optionally, the technique of the annealing includes：Laser annealing.
Optionally, the front of the semiconductor substrate has alignment mark, from the back side of the semiconductor substrate to described
Semiconductor substrate carries out the second ion implanting, includes to form back side photodiode doped region：In the semiconductor substrate
The back side forms patterned mask layer, and the pattern of the mask layer is aligned according to the alignment mark；With the patterning
Mask layer be mask, to the semiconductor substrate carry out the second ion implanting, to form back side photodiode doped region.
In order to solve the above technical problems, the embodiment of the present invention provides a kind of imaging sensor, including：Semiconductor substrate, institute
Stating semiconductor substrate has front and back；Front photodiode doped region is located at the front of the semiconductor substrate；The back side
Photodiode doped region, be located at the semiconductor substrate the back side, wherein the front photodiode doped region with it is described
Back side photodiode doped region connection.
Optionally, development length of the front photodiode doped region on the thickness direction of the semiconductor substrate
It is 1 μm to 2.5 μm；And/or extension of the back side photodiode doped region on the thickness direction of the semiconductor substrate
Length is 1 μm to 2.5 μm.
Optionally, the thickness of the semiconductor substrate is 4 μm to 5 μm.
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 semiconductor substrate has front and back；From described half
The semiconductor substrate that just faces of conductor substrate carries out the first ion implanting, to form front photodiode doped region；From
The back side of the semiconductor substrate carries out the second ion implanting to the semiconductor substrate, to form back side photodiode doping
Area, wherein the front photodiode doped region is connected to the back side photodiode doped region.Using the above scheme,
By being respectively formed photodiode doped region in the front of semiconductor substrate and the back side, and front photodiode doped region with
Back side photodiode doped region connection, can obtain the photodiode doped region of perforation semiconductor substrate, compared to existing
The depth of photodiode doped region only accounts for a part for the thickness of semiconductor substrate in technology, causes to pass through photoelectricity in infrared ray
During diode, light absorption is very few, it is difficult to enough photoelectrons is generated, using the scheme of the embodiment of the present invention, photoelectricity two
The depth of pole pipe doped region is deeper, can absorb enough incident photons during infrared ray passes through photodiode, from
And enough photoelectrons are generated, the sensitivity of described image sensor is improved, and improve the full-well capacity of photodiode.
Further, the second ion implanting is carried out to the semiconductor substrate from the back side of the semiconductor substrate, to be formed
Further include the step for carrying out being thinned to preset thickness to the semiconductor substrate from the back side before the photodiode doped region of the back side
Suddenly.In embodiments of the present invention, by the way that the semiconductor substrate is thinned, the thickness of semiconductor substrate can be reduced, is had
Help reduction that front photodiode doped region is made to correspond the process implementing difficulty being connected to back side photodiode doped region.
Description of the drawings
Fig. 1 is a kind of vertical view of imaging sensor in the prior art；
Fig. 2 is cross-sectional views of the Fig. 1 along cutting line A1-A2；
Fig. 3 is cross-sectional views of the Fig. 1 along cutting line B1-B2；
Fig. 4 is a kind of flow chart of the forming method of imaging sensor in the embodiment of the present invention；
Fig. 5 is a kind of vertical view of imaging sensor in the embodiment of the present invention；
Fig. 6 to Fig. 9 is that each step respective devices are cutd open in a kind of forming method of imaging sensor in the embodiment of the present invention
Face structural schematic diagram；
Figure 10 is cross-sectional views of the Fig. 5 along cutting line D1-D2.
Specific implementation mode
In the prior art, infrared imaging sensor is widely applied in fields such as monitoring, automobile, medical treatment, so
And existing infrared imaging sensor sensitivity is relatively low.
In conjunction with being a kind of vertical view of imaging sensor in the prior art referring to figs. 1 to Fig. 3, Fig. 1, Fig. 2 is Fig. 1 along cutting
The cross-sectional view of line A1-A2, Fig. 3 are cross-sectional views of the Fig. 1 along cutting line B1-B2.
Described image sensor may include semiconductor substrate 100, isolation structure 110, photodiode doped region 120,
Transmit grid 130 and floating diffusion region 132.
Wherein, the isolation structure 110 is located in the semiconductor substrate 100, for adjacent photodiode to be isolated
Doped region 120.
The photodiode doped region 120 is located in the semiconductor substrate 100.
The transmission grid (Transfer Gate, TG) 130 is located at the surface of the semiconductor substrate 100, the photoelectricity
Diode doped region 120 can be located in the semiconductor substrate 100 of 130 side of the transmission grid, the floating diffusion region
(Floating Diffusion, FD) 132 can be located in the semiconductor substrate 100 of 130 other side of the transmission grid.
It is described on the surface of the semiconductor substrate 100, described image sensor can also include metallic grid (Metal
Grid) 150, filter (Color filter) 152 and camera lens (Micro-lens) 154.
It should be pointed out that in order to avoid Fig. 1 is excessively complicated, does not draw in Fig. 1 and mark out described image sensing
All device architectures of device.In addition, the arrow in Fig. 2 and Fig. 3 is used to indicate the incident path of incident light.
The present inventor is by the study found that in above-mentioned imaging sensor, due to photodiode doped region 120
Depth it is usually smaller, and the wavelength of infrared ray is usually longer (0.76um to 1000um), causes to pass through photoelectricity two in infrared ray
During pole pipe doped region 120, light absorption is very few, it is difficult to generate enough photoelectrons, cause the sensitivity of imaging sensor
It is relatively low.
Specifically, incident light luminous intensity I of position to be calculated in medium may be used following luminous intensity equations and carry out
It calculates：
I=I0exp(-αx)；
Wherein, I is used to indicate the luminous intensity of incident light position to be calculated in medium；I0For indicating that incident light enters matchmaker
Original luminous intensity when Jie；α is for indicating the absorption coefficient of light；X is by indicating that incident light is propagated to from incoming position based on described wait for
Calculate the propagation distance of position.
From the foregoing, it will be observed that the luminous intensity I and absorption coefficient of light α and propagation distance x of position to be calculated are related in medium, light
Absorption coefficient is higher, and propagation distance x is longer, and luminous intensity I is smaller, more the light for contributing to absorption more, to generate enough photoelectricity
Son.
Further, the absorption coefficient of light α may be used following formula and be calculated：
The π k/ of α=4 λ；
Wherein, k is related with the type of medium for the parameter of the attenuation degree of characterization luminous energy for indicating extinction coefficient；λ
Wavelength for indicating incident light.
From the foregoing, it will be observed that under the premise of medium (i.e. photodiode doped region 120) is consistent, absorption coefficient of light α with it is original
Luminous intensity I0It is unrelated, and it is related with the wavelength X of incident light, and the wavelength X of the incident light is longer (for example, by using infrared ray), described
Absorption coefficient of light α is smaller, causes the light absorbed fewer, it is difficult to generate enough photoelectrons.
There is an urgent need for a kind of methods of the propagation distance x of enhancing infrared ray, and infrared ray is made to pass through photodiode doped region 120
In the process, more light are absorbed to generate enough photoelectrons, improve the sensitivity of imaging sensor.
However, the present inventor has found after further research, and in existing imaging sensor, photodiode
The depth of doped region 120 is limited by ion implantation technology, it is difficult to unlimitedly be increased.Specifically, current ion is based on to note
The technological ability entered, for the doping depth of photodiode doped region 120 at 2.5 μm or so, absorbing amount is less, it is difficult to generate foot
Enough photoelectrons cause the sensitivity of imaging sensor relatively low.
In embodiments of the present invention, semiconductor substrate is provided, the semiconductor substrate has front and back；From described half
The semiconductor substrate that just faces of conductor substrate carries out the first ion implanting, to form front photodiode doped region；From
The back side of the semiconductor substrate carries out the second ion implanting to the semiconductor substrate, to form back side photodiode doping
Area, wherein the front photodiode doped region is connected to the back side photodiode doped region.Using the above scheme,
By being respectively formed photodiode doped region in the front of semiconductor substrate and the back side, and front photodiode doped region with
Back side photodiode doped region connection, can obtain the photodiode doped region of perforation semiconductor substrate, compared to existing
The depth of photodiode doped region only accounts for a part for the thickness of semiconductor substrate in technology, causes to pass through photoelectricity in infrared ray
During diode, light absorption is very few, it is difficult to enough photoelectrons is generated, using the scheme of the embodiment of the present invention, photoelectricity two
The depth of pole pipe doped region is deeper, can absorb enough incident photons during infrared ray passes through photodiode, from
And enough photoelectrons are generated, the sensitivity of described image sensor is improved, and improve the full-well capacity of photodiode.
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.
With reference to Fig. 4, Fig. 4 is a kind of flow chart of the forming method of imaging sensor, described image in the embodiment of the present invention
The forming method of sensor may include step S21 to step S23：
Step S21：Semiconductor substrate is provided, the semiconductor substrate has front and back；
Step S22：The first ion implanting is carried out from the semiconductor substrate that just faces of the semiconductor substrate, to be formed
Front photodiode doped region；
Step S23：The second ion implanting is carried out to the semiconductor substrate from the back side of the semiconductor substrate, to be formed
Back side photodiode doped region, wherein the front photodiode doped region and the back side photodiode doped region
Connection.
Above-mentioned each step is illustrated with reference to Fig. 5 to Figure 10.
With reference to Fig. 5, Fig. 5 is a kind of vertical view of imaging sensor in the embodiment of the present invention, and described image sensor can be with
Including semiconductor substrate 200, isolation structure 210, photodiode doped region 220, transmission grid 230.It should be pointed out that being
It avoids Fig. 5 excessively complicated, does not draw and mark out all device architectures of described image sensor in Figure 5.
Fig. 6 to Fig. 9 is that each step respective devices are cutd open in a kind of forming method of imaging sensor in the embodiment of the present invention
Face structural schematic diagram.It should be pointed out that Fig. 6 to Fig. 9 is cross-sectional views of the Fig. 5 along cutting line D1-D2.
With reference to Fig. 6, semiconductor substrate 200 is provided, the semiconductor substrate 200 has front and back, partly led from described
The semiconductor substrate 200 that just faces of body substrate 200 carries out the first ion implanting, to form front photodiode doped region
220。
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).
It just before the first ion implanting of progress of the semiconductor substrate 200, is gone back from the semiconductor substrate 200
Isolation structure 210 can be formed in the semiconductor substrate 200, the isolation structure 210 is for being isolated the front photoelectricity
Diode doped region 220, to prevent the photo-generated carrier of different zones to be diffused into adjacent area.
In specific implementation, the isolation structure 210 may include shallow-trench isolation (Shallow Trench
Isolation, STI) structure and deep trench isolation (Deep Trench Isolation, DTI) structure.It should be pointed out that institute
Stating deep groove isolation structure can also be formed by the way of ion implanting, be properly termed as deep inject again at this time and (Deep is isolated
Implant Isolation) (Photo Diode Isolation) structure is isolated in structure or photodiode.
The doping type of the front photodiode doped region 220 includes N-type.Specifically, the front photoelectricity two
The doping type of pole pipe doped region 220 is opposite with the doping type of the semiconductor substrate 200.If the semiconductor substrate
200 doping type is N-type, then the Doped ions of the front photodiode doped region 220 are p-type ion, such as including
Boron (B) or BF2；, whereas if the doping type of the semiconductor substrate 200 is p-type, then the front photodiode doping
The Doped ions in area 220 are N-type ion, such as including phosphorus (P) or arsenic (As).The usually doping class of setting semiconductor substrate 200
Type is p-type, and the doping type of front photodiode doped region 220 is N-type.
As a unrestricted example, the Doped ions of the front photodiode doped region 220 can be arsenic
Ion.
Further, the front photodiode doped region 220 is on the thickness direction of the semiconductor substrate 200
Development length cannot be excessive, otherwise will increase the difficulty of ion implantation technology；The front photodiode doped region 220 is in institute
The development length stated on the thickness direction of semiconductor substrate 200 cannot be too small, is otherwise difficult to be subsequently formed two pole of back side photoelectricity
When pipe doped region, the connection of back side photodiode doped region and front photodiode doped region 220 is realized.
As a unrestricted example, the front photodiode doped region 220 is in the semiconductor substrate 200
Thickness direction on development length can be 1 μm to 2.5 μm.Preferably, the front photodiode doped region 220 is in institute
It can be 2 μm to 2.5 μm to state the development length on the thickness direction of semiconductor substrate 200.
From the semiconductor substrate 200 just after the semiconductor substrate 200 carries out the first ion implanting, may be used also
To anneal to the front photodiode doped region 220.
Wherein, the annealing process can be selected from：Furnace anneal, rapid thermal annealing (Rapid Thermal
Annealing, RTA), spike annealing (Spike Annealing) or laser annealing (Laser Annealing).
With reference to Fig. 7, in semiconductor substrate 200 and the surface of semiconductor substrate 200, logical device and pixel are formed
The other parts of device, such as may include transmission grid 230, floating diffusion region 232 and pixel circuit area 240.
Wherein, the transmission grid 230 can be located at the surface of the semiconductor substrate 200, and the photodiode is mixed
Miscellaneous area 220 can be located in the semiconductor substrate 200 of 230 side of the transmission grid, and the floating diffusion region 232 can be located at
In the semiconductor substrate 200 of 230 other side of the transmission grid.
The pixel circuit area 240 may include that form selection transistor, reset transistor and source each with transistor etc.
The device of kind transistor appropriate.It should be pointed out that in embodiments of the present invention, for specific pixel circuit area 240
Composition is not restricted.
With reference to Fig. 8, semiconductor devices is formed in the front of the semiconductor substrate 200, forms metal interconnection structure, and
It is bonded with carrying wafer (Carrier Wafer), then the semiconductor substrate 200 be thinned to from the back side default
Thickness.
It should be pointed out that in embodiments of the present invention, being formed after front photodiode doped region 220, described
The treatment process that the front of semiconductor substrate 200 carries out can be any conventional treatment process of existing imaging sensor,
The embodiment of the present invention is not restricted this.
Further, the thickness of the semiconductor substrate 200 cannot be excessive, otherwise will increase the difficulty of ion implantation technology
Degree, and be difficult to when being subsequently formed back side photodiode doped region, realize back side photodiode doped region and front lighting
The corresponding connection of electric diode doped region 220；The thickness of the semiconductor substrate 100 cannot be too small, otherwise to imaging sensor
Sensitivity improvement it is very few.Preferably, the thickness of the semiconductor substrate 200 is 4 μm to 5 μm.
In embodiments of the present invention, by the way that the semiconductor substrate 200 is thinned, semiconductor substrate can be reduced
It is real to help the technique for reducing and back side photodiode doped region being made to be connected to front photodiode doped region 220 for 200 thickness
Apply difficulty.
With reference to Fig. 9, second ion implanting is carried out to the semiconductor substrate 200 from the back side of the semiconductor substrate 200,
To form back side photodiode doped region 221, wherein the front photodiode doped region 220 and the back side photoelectricity
Diode doped region 221 is connected to.
In specific implementation, the front photodiode doped region 220 may include multiple front photodiodes, institute
It may include multiple back side photodiodes, the front photodiode doped region to state back side photodiode doped region 221
220 are used to indicate corresponding front photodiode and back side photoelectricity two with the back side photodiode doped region 221 connection
Pole pipe is connected to one by one.
Further, the front of the semiconductor substrate 200 can have alignment mark, from the semiconductor substrate 200
The back side the second ion implanting is carried out to the semiconductor substrate 200, the step of to form back side photodiode doped region 221
May include：Patterned mask layer is formed at the back side of the semiconductor substrate 200, the pattern of the mask layer is according to
Alignment mark is aligned；Using the patterned mask layer as mask, the second ion note is carried out to the semiconductor substrate 200
Enter, to form back side photodiode doped region 221.
Specifically, the positive alignment mark (Alignment Mark) of the semiconductor substrate 200 can be multiplexed master
The alignment mark of dynamic area (Active Area, AA) layer can also use other that can be determined at the back side of semiconductor substrate 200
Alignment mark.
Further, can also include to the back light after forming the back side photodiode doped region 221
The step of electric diode doped region 221 is annealed.
It should be pointed out that during annealing to the back side photodiode doped region 221, it is preferred to use
High-temperature process only is carried out on the back side of semiconductor substrate 200 and does not influence the positive annealing process of semiconductor substrate 200.Specifically
For, due to before forming the back side photodiode doped region 221, being formed in the front of the semiconductor substrate 200
There is metal interconnection structure, and be all made of copper (Cu) metal structure in kinds of processes platform, and metal interconnection structure is moved back
Fire can cause intrametallic tissue to tend to balance state, and conductivity increases and resistivity reduces, and influences the performance of imaging sensor.
Preferably, the technique of the annealing may include：Laser annealing (Laser Annealing).Specifically, activation is moved back
Fire is, using laser heating materials surface, not the front to semiconductor substrate 200 and the back side carries out integration high-temperature process.It can
With understanding, when selecting other annealing process, method appropriate should be used to carry out heat to the front of semiconductor substrate 200
Isolation.
Further, the back side photodiode doped region 221 is on the thickness direction of the semiconductor substrate 200
Development length cannot be excessive, otherwise will increase the difficulty of ion implantation technology；The back side photodiode doped region 221 is in institute
The development length stated on the thickness direction of semiconductor substrate 200 cannot be too small, is otherwise difficult to realize back side photodiode doping
The connection in area 221 and front photodiode doped region 220.
As a unrestricted example, the back side photodiode doped region 221 is in the semiconductor substrate 200
Thickness direction on development length can be 1 μm to 2.5 μm.
Preferably, 221 the prolonging on the thickness direction of the semiconductor substrate 200 of back side photodiode doped region
Elongation can be 2 μm to 2.5 μm, when the semiconductor substrate 200 is thinned to 4 μm to 5 μm of preset thickness, to realize the back side
The connection of photodiode doped region 221 and front photodiode doped region 220.
Other content in relation to the back side photodiode doped region 221, such as principle, specific implementation and advantageous effect
The associated description about back side photodiode doped region 220 above and shown in Fig. 6 is please referred to, details are not described herein again.
In embodiments of the present invention, it is mixed by being respectively formed photodiode in the front of semiconductor substrate 200 and the back side
Miscellaneous area, and front photodiode doped region 220 is connected to back side photodiode doped region 221, can obtain penetrating through partly leading
The photodiode doped region of body substrate, compared with the prior art in the depth of photodiode doped region only account for semiconductor substrate
Thickness a part, cause infrared ray pass through photodiode during, light absorption is very few, it is difficult to generate enough light
Electronics, using the scheme of the embodiment of the present invention, the depth of photodiode doped region is deeper, can pass through photoelectricity two in infrared ray
During pole pipe, enough incident photons are absorbed, to generate enough photoelectrons, improve the sensitive of described image sensor
Degree, and improve the full-well capacity of photodiode.
0, Figure 10 is cross-sectional views of the Fig. 5 along cutting line D1-D2 referring to Fig.1.Described image sensor can wrap
Include semiconductor substrate 200, isolation structure 210, front photodiode doped region 220 and back side photodiode doped region
221, wherein the front photodiode doped region 220 is connected to the back side photodiode doped region 221.
Described image sensor can also include metallic grid 250, filter 252 and camera lens 254.In addition, the arrow in figure
Head is used to indicate the incident path of incident light.
Wherein, the metallic grid 250 is mostly latticed, and surrounds the filter 252.In embodiments of the present invention, right
It is not restricted in the concrete type of filter 252.
It is pointed out that development length of the isolation structure 210 on the thickness direction of the semiconductor substrate 200
It is bigger, more contribute to preferably to front photodiode doped region 220 and back side photodiode doped region 221 carry out every
From.
As a unrestricted example, the isolation structure 210 is on the thickness direction of the semiconductor substrate 200
Development length can be 1 μm to 5 μm.
In embodiments of the present invention, a kind of imaging sensor is additionally provided, referring to Fig.1 0, described image sensor can wrap
It includes：
Semiconductor substrate 200, the semiconductor substrate 200 have front and back；
Front photodiode doped region 220 is located at the front of the semiconductor substrate 200；
Back side photodiode doped region 221 is located at the back side of the semiconductor substrate 200, wherein the front photoelectricity
Diode doped region 220 is connected to the back side photodiode doped region 221.
Further, the front photodiode doped region 220 is on the thickness direction of the semiconductor substrate 200
Development length can be 1 μm to 2.5 μm；And/or the back side photodiode doped region 221 is in the semiconductor substrate 200
Thickness direction on development length can be 1 μm to 2.5 μm.
The thickness of the semiconductor substrate 200 can be 4 μm to 5 μm.
Further, the imaging sensor can also include isolation structure 210, be formed in the semiconductor substrate
Front, wherein the depth of the isolation structure 210 can be 1 μm to 5 μm.
It is please referred to above and shown in Fig. 4 to Figure 10 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.
In addition, CIS may include preceding illuminated (Front-side Illumination, abbreviation FSI) CIS and rear illuminated
(Back-side Illumination, abbreviation BSI) CIS, the rear illuminated CIS are referred to as back-illuminated type CIS.In back-illuminated type
In CIS, incident light from back side illuminaton to photodiode on generate photo-generated carrier, and then form electric signal.
In embodiments of the present invention, described image sensor can be back-illuminated type CIS.
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 semiconductor substrate has front and back；
The first ion implanting is carried out from the semiconductor substrate that just faces of the semiconductor substrate, to form two pole of front photoelectricity
Pipe doped region；
The second ion implanting is carried out to the semiconductor substrate from the back side of the semiconductor substrate, to form two pole of back side photoelectricity
Pipe doped region, wherein the front photodiode doped region is connected to the back side photodiode doped region.
2. the forming method of imaging sensor according to claim 1, which is characterized in that
Development length of the front photodiode doped region on the thickness direction of the semiconductor substrate is 1 μm to 2.5 μ
m；And/or
Development length of the back side photodiode doped region on the thickness direction of the semiconductor substrate is 1 μm to 2.5 μ
m。
3. the forming method of imaging sensor according to claim 1, which is characterized in that from the back of the body of the semiconductor substrate
Before carrying out the second ion implanting in face of the semiconductor substrate, further include：
The semiconductor substrate is carried out from the back side to be thinned to preset thickness.
4. the forming method of imaging sensor according to claim 3, which is characterized in that the preset thickness is 4 μm to 5
μm。
5. the forming method of imaging sensor according to claim 1, which is characterized in that forming the back side photoelectricity two
Further include after pole pipe doped region：It anneals to the back side photodiode doped region.
6. the forming method of imaging sensor according to claim 5, which is characterized in that the technique of the annealing includes：
Laser annealing.
7. the forming method of imaging sensor according to claim 1, which is characterized in that the front of the semiconductor substrate
With alignment mark, the second ion implanting is carried out to the semiconductor substrate from the back side of the semiconductor substrate, to form the back of the body
Face photodiode doped region includes：
Patterned mask layer is formed at the back side of the semiconductor substrate, the pattern of the mask layer is according to the alignment mark
It is aligned；
Using the patterned mask layer as mask, the second ion implanting is carried out to the semiconductor substrate, to form back light
Electric diode doped region.
8. a kind of imaging sensor, which is characterized in that including：
Semiconductor substrate, the semiconductor substrate have front and back；
Front photodiode doped region is located at the front of the semiconductor substrate；
Back side photodiode doped region is located at the back side of the semiconductor substrate, wherein the front photodiode doping
Area is connected to the back side photodiode doped region.
9. imaging sensor according to claim 8, which is characterized in that
Development length of the front photodiode doped region on the thickness direction of the semiconductor substrate is 1 μm to 2.5 μ
m；And/or
Development length of the back side photodiode doped region on the thickness direction of the semiconductor substrate is 1 μm to 2.5 μ
m。
10. imaging sensor according to claim 8, which is characterized in that
The thickness of the semiconductor substrate is 4 μm to 5 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810168637.XA CN108321164A (en) | 2018-02-28 | 2018-02-28 | Imaging sensor and forming method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810168637.XA CN108321164A (en) | 2018-02-28 | 2018-02-28 | Imaging sensor and forming method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN108321164A true CN108321164A (en) | 2018-07-24 |
Family
ID=62900951
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810168637.XA Pending CN108321164A (en) | 2018-02-28 | 2018-02-28 | Imaging sensor and forming method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108321164A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110137191A (en) * | 2019-04-19 | 2019-08-16 | 德淮半导体有限公司 | Imaging sensor and forming method thereof |
| CN110729318A (en) * | 2019-09-30 | 2020-01-24 | 芯盟科技有限公司 | Image sensor and method for manufacturing the same |
| CN112259624A (en) * | 2020-09-08 | 2021-01-22 | 联合微电子中心有限责任公司 | Image sensor and forming method thereof |
| CN112397534A (en) * | 2019-08-19 | 2021-02-23 | 豪威科技股份有限公司 | Image sensor for infrared sensing and method of manufacturing the same |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040080638A1 (en) * | 2002-10-23 | 2004-04-29 | Won-Ho Lee | CMOS image sensor including photodiodes having different depth accordong to wavelength of light |
| JP2007299989A (en) * | 2006-05-01 | 2007-11-15 | Fujifilm Corp | Method for manufacturing semiconductor device, solid-state imaging device and method for manufacturing the same |
| JP2009302448A (en) * | 2008-06-17 | 2009-12-24 | Panasonic Corp | Manufacturing method of solid-state imaging element |
| CN102088026A (en) * | 2009-12-07 | 2011-06-08 | 佳能株式会社 | Manufacturing method of solid-state image pickup apparatus |
| CN102163611A (en) * | 2010-02-18 | 2011-08-24 | 佳能株式会社 | Solid state image pickup device and method for manufacturing solid state image pickup device |
-
2018
- 2018-02-28 CN CN201810168637.XA patent/CN108321164A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040080638A1 (en) * | 2002-10-23 | 2004-04-29 | Won-Ho Lee | CMOS image sensor including photodiodes having different depth accordong to wavelength of light |
| JP2007299989A (en) * | 2006-05-01 | 2007-11-15 | Fujifilm Corp | Method for manufacturing semiconductor device, solid-state imaging device and method for manufacturing the same |
| JP2009302448A (en) * | 2008-06-17 | 2009-12-24 | Panasonic Corp | Manufacturing method of solid-state imaging element |
| CN102088026A (en) * | 2009-12-07 | 2011-06-08 | 佳能株式会社 | Manufacturing method of solid-state image pickup apparatus |
| CN102163611A (en) * | 2010-02-18 | 2011-08-24 | 佳能株式会社 | Solid state image pickup device and method for manufacturing solid state image pickup device |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110137191A (en) * | 2019-04-19 | 2019-08-16 | 德淮半导体有限公司 | Imaging sensor and forming method thereof |
| CN112397534A (en) * | 2019-08-19 | 2021-02-23 | 豪威科技股份有限公司 | Image sensor for infrared sensing and method of manufacturing the same |
| CN110729318A (en) * | 2019-09-30 | 2020-01-24 | 芯盟科技有限公司 | Image sensor and method for manufacturing the same |
| CN112259624A (en) * | 2020-09-08 | 2021-01-22 | 联合微电子中心有限责任公司 | Image sensor and forming method thereof |
| CN112259624B (en) * | 2020-09-08 | 2023-05-23 | 联合微电子中心有限责任公司 | Image sensor and method of forming the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7875918B2 (en) | Multilayer image sensor pixel structure for reducing crosstalk | |
| KR100710207B1 (en) | Method for manufacturing CMOS image sensor | |
| KR100778856B1 (en) | manufacturing method for CMOS image sensor | |
| CN108321164A (en) | Imaging sensor and forming method thereof | |
| JP2004165589A (en) | Cmos image sensor and method for manufacturing the same | |
| KR101301900B1 (en) | Co-implant for backside illumination sensor | |
| TW201137980A (en) | Improved laser anneal for image sensors | |
| TW201001684A (en) | Image sensor with low electrical cross-talk | |
| JP2006294871A (en) | Solid-state imaging apparatus | |
| KR100836507B1 (en) | Method for fabricating cmos image sensor | |
| JP2008091781A (en) | Amplification type solid-state imaging element | |
| CN100466283C (en) | CMOS image sensor and method for manufacturing the same | |
| JP2008300835A (en) | Vertical cmos image sensor and its fabrication process | |
| CN106952931B (en) | A kind of manufacturing method of cmos image sensor | |
| CN108470741A (en) | Imaging sensor and forming method thereof | |
| KR20140099809A (en) | Manufacturing method of solid-state image pickup device and solid-state image pickup device | |
| TW200837940A (en) | Image sensor devices, methods for forming the same and semiconductor devices | |
| KR100625945B1 (en) | Method for manufacturing photodiode in cmos image sensor | |
| KR100731095B1 (en) | Method for manufacturing a cmos image sensor | |
| JPH11121729A (en) | Band gap designed active pickcell cell | |
| CN100576511C (en) | The manufacture method of cmos image sensor | |
| KR20090071067A (en) | Image sensor and method for manufacturing thereof | |
| KR101550434B1 (en) | Method of fabricating image sensor | |
| JP2009111118A (en) | Rear-surface irradiation type solid-state imaging element, and manufacturing method therefor | |
| CN110176467A (en) | Cmos image sensor and its manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20180724 |