Patent Publication Number: US-2019198536-A1

Title: Image Sensor and Forming Method Thereof

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Chinese Patent Application No. CN201711405000.X, entitled “Image Sensor and Forming Method Thereof”, filed with SIPO on Dec. 22, 2017, the contents of which are incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the technical field of semiconductor devices, and in particular, to an image sensor and a forming method thereof. 
     BACKGROUND 
     A semiconductor image sensor is a semiconductor device for converting optical image signals to electrical image signals. A CMOS (Complementary Metal Oxide Semiconductor) image sensors are solid-state image sensors which have been developed in past decades rapidly, for their obvious advantages such as that in an image sensor, the sensor portion and the control circuit portion can be integrated in a same chip, the CMOS image sensors have small sizes, they are low in power consumption and can be made with low cost,. Compared to the traditional CCD (Charge Coupled Device) image sensor, the CMOS image sensors have more advantages and are naturally more popular. 
     An existing CMOS image sensor includes a photoelectric part for converting an optical signal to electrons, such as a photoelectric diode formed in a silicon substrate. In addition, a dielectric layer is also formed on a surface of the silicon substrate over the photoelectric diode, a metal interconnection layer is formed in the dielectric layer, and the metal interconnection layer is used for electrically connecting the photoelectric diode and a peripheral circuit. For the above described CMOS image sensor, the front surface is the one having the dielectric layer and the metal interconnection layer, and the back surface is the other opposing surface. Based on light irradiation direction, the CMOS image sensors can be classified into front-side illumination (FSI) CMOS image sensors or back-side illumination (BSI) CMOS image sensors. 
     For the front-side illumination CMOS image sensor, light is incident on the front surface of the CMOS image sensor. Incident light passes through a number of dielectric layers and metal interconnection layers in the light path before illuminating on the photoelectric diode, the amount of light absorbed by the photoelectric diode may be limited, resulting in lower quantum efficiency. For the back-side illumination CMOS image sensor, light is incident on the photoelectric diode from the back surface, thereby similar loss of light is eliminated, improving the photon-to-electron conversion efficiency. 
     For existing back-side illumination CMOS image sensors, there is serious crosstalk problem from lateral scattering, resulting in poor photoelectric conversion accuracy and stability. A problem needs a solution is how to reduce optical cross talk and improve photoelectric conversion accuracy and stability for aback-side illumination CMOS image sensors. 
     SUMMARY 
     The present disclosure provides an image sensor and forming method thereof. 
     The image sensor comprises: a substrate divided into a plurality of first zones and a plurality of second zones; a plurality of photoelectric diodes patterned in a sensor layer on a surface of the substrate, wherein the plurality of photoelectric diodes each is arranged overlapping one of the plurality of first zones; an isolation structure disposed on the sensor layer; a plurality of color filter lenses disposed on the first isolation layer and aligned to the plurality of photoelectric diodes; a plurality of barrier structures each disposed between two adjacent color filter lenses of the plurality of color filter lenses, wherein the plurality of barrier structures align to the plurality of second zones; and a plurality of micro lenses each on arranged on one of the plurality of color filter lens; wherein a refractive index of the plurality of barrier structures is smaller than a refractive index of the plurality of color filter lenses. 
     Optionally, the refractive index of the barrier layer is in a range from 1.2 to 1.65. 
     Optionally, a material of the plurality of barrier structures comprises: SiO 2 , MgF 2 , Al 2 O 3  or Ti 3 O 5 . 
     Optionally, the plurality of color filter lenses comprises red color filter lenses, green color filter lenses or blue color filter lenses; wherein the isolation structure comprises: a first isolation layer disposed on the sensor layer and a second isolation layer disposed on the first isolation layer; wherein a metal grid is patterned in the second isolation layer aligning to the plurality of barrier structures. 
     The present disclosure further provides a method of forming an image sensor, comprising: providing a substrate; forming a sensor layer on a surface of the substrate, patterning a plurality of photoelectric diodes in the sensor layer; forming an isolation structure on the sensor layer; forming a plurality of color filter lenses on the isolation structure aligned to the plurality of photoelectric diodes; forming a plurality of barrier structures on the isolation structure; wherein a refractive index of the barrier structures is smaller than a refractive index of the plurality of color filter lenses; and forming a micro lens structure on at least one of the plurality of color filter lenses. 
     Optionally, forming a plurality of barrier structures comprises: forming a trench between adjacent two of the plurality of color filter lenses, and filling trench with a barrier material. 
     Optionally, a refractive index of the barrier layer is in a range from 1.2 to 1.65. 
     Optionally, the barrier material comprises: SiO2, MgF2, Al2O3 or Ti3O5; and wherein a forming process of the barrier structures comprises: a chemical vapor deposition process or a physical vapor deposition process. 
     Optionally, the plurality of color filter lenses comprises red color filter lenses, green color filter lenses or blue color filter lenses. 
     Optionally, the isolation structure comprises: the isolation structure comprises: a first isolation layer disposed on the sensor layer and a second isolation layer disposed on the first isolation layer. 
     Optionally, the method further comprises forming a metal grid under the plurality of barrier structures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a conventional back-side illumination CMOS image sensor. 
         FIG. 2  to  FIG. 8  are schematic diagrams of fabrication steps in forming an image sensor of according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The foregoing objectives, features, and advantages of the present disclosure will become more apparent from the following detailed description of specific embodiments of the disclosure in conjunction with the accompanying drawings. In the detailed description of the embodiments of the present disclosure, for convenience of description, the schematic diagram will be partially enlarged not according to an ordinary ratio, and the schematic diagram is only an example, which should not limit the protection scope of the present disclosure. In addition, three-dimensional space dimensions of length, width, and depth should be comprised in actual production. 
     It should be noted that the illustration provided in the present embodiment merely illustrates the basic concept of the present disclosure by way of illustration. Although only components related to the present disclosure are shown in the illustration, the number, shape and size drawing of the components in actual implementation are not limited. The form, quantity and proportion of various components in actual implementation may be randomly changed, and the layout of the components may also be more complicated. 
     As described in the background, crosstalking in back-side illumination CMOS image sensors is serious. 
       FIG. 1  is a structural schematic diagram of a conventional back-side illumination CMOS image sensor. 
     Referring to  FIG. 1 , a back-side illumination CMOS image sensor according to one embodiment includes: a substrate  100 ; a plurality of photoelectric diodes  102  disposed on a surface of the substrate  100 ; isolation layers  103  disposed on surfaces of the photoelectric diodes  102 ; a plurality of color filter lenses  104  disposed on surfaces of the isolation layers  103 , wherein each color filter lens  104  corresponds to one photoelectric diode  102 ; and micro lenses  105  disposed on surfaces of the color filter lenses  104 . 
     In the above back-side illumination CMOS image sensor, light coming from different incident angles within the view of each of the micro lenses  105  is focused into the underneath color filter lens  104  where photons of undesired wavelengths are filtered out, and monochromatic light corresponding to the color filter lenses  104  forms before the photoelectric diodes  102 . The monochromatic light is absorbed by the underneath photoelectric diode  102 , and excites electron-hole pairs, thereby implementing the photoelectric conversion. 
     Specifically, taking a color filter lens  104   b  as an example, light in different incident angles enters the color filter lens  104   b;  and the light in different angles comprises incident light A irradiated into the color filter lens  104   b,  incident light B irradiated on an interface between the color filter lens  104   b  and a color filter lens  104   a,  and incident light C irradiated on an interface between the color filter lens  104   b  and a color filter lens  104   c.  The incident light A can enter the range of the corresponding photoelectric diode  102  after passing through the color filter lens  104   b  so as to implement the photoelectric conversion within the corresponding photoelectric diode  102 . 
     However, when the incident light B reaches the interface between the color filter lens  104   b  and the color filter lens  104   a,  may easily enter the adjacent color filter lens  104   a.  Therefore, the incident light B is not completely filtered by the color filter lens  104   b.  After the unfiltered incident light B enters the color filter lens  104   a  from the color filter lens  104   b,  the incident light B is further filtered by the color filter lens  104   a,  and is finally irradiated on the photoelectric diode  102  underneath the color filter lens  104   a,  thereby resulting in a cross talk of the back-side illumination CMOS image sensor. Similarly, the incident light C easily enters the color filter lens  104   c  from  104   b , is further filtered by the color filter lens  104   c,  and is then irradiated on the photoelectric diode  102  underneath the color filter lens  104   c,  thereby resulting in across talk of the back-side illumination CMOS image sensor. 
     In order to solve the cross talking problem, the present disclosure provides an image sensor and the sensor&#39;s forming method. The image sensor includes barrier layers, formed between the adjacent color filter lenses, the refractive index of the barrier layer material is smaller than the refractive index of the color filter lens material. The barrier layers can prevent unwanted passing of incident light into adjacent color filter lens to reduce or eliminate cross talk. 
     A method of forming such an image sensor is described in details in the following texts. 
       FIG. 2  to  FIG. 8  are schematic diagrams of fabrication steps in forming an image sensor of according to one embodiment of the present disclosure. 
     Referring to  FIG. 2 , a substrate  200  is provided; a sensor layer  201  is formed on a surface of the substrate  200 , the sensor layer  201  is divided in zones aligned with the photodiodes. Zone one or A aligns with diodes and zone two or B aligns with the gap between adjacent photodiodes. 
     The substrate  200  comprises: a supporting substrate (not shown), a dielectric layer (not shown) disposed on the surface of a supporting substrate, and an electric interconnection structure (not shown) disposed in the dielectric layer. 
     The method of forming the substrate  200  and the sensor layer  201  comprises: providing a semiconductor substrate (not shown); forming a sensor layer  201  in the semiconductor substrate, wherein the sensor layer  201  comprises a plurality of first zones A and second zones B between the adjacent first zones A along a direction parallel to a surface of the substrate, and the sensor layer  201  in the first zone A has a photoelectric diode  202 ; forming a dielectric layer on a first surface of the semiconductor substrate after the sensor layer  201  is formed, wherein the dielectric layer has an electric interconnection structure therein; forming a supporting substrate on a surface of the dielectric layer; thinning the semiconductor substrate from a second surface of the semiconductor substrate after the supporting substrate is formed until the sensor layer  201  is exposed, and the second surface is opposite to the first surface. 
     In the present embodiment, the semiconductor substrate is a silicon substrate. 
     In other embodiments, the semiconductor substrate can be a germanium substrate, a silicon carbide substrate, a germanium-silicon substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate, the semiconductor substrate is doped with P-type or N-type ions. 
     In the present embodiment, the image sensor is a back-side illumination CMOS image sensor and the sensor layer  201  is formed by a semiconductor substrate. 
     In the present embodiment, the semiconductor substrate is a silicon substrate, and the silicon substrate is doped with a P-type well area. The forming steps of the sensor layer  201  comprise: injecting N-type ions onto the first surface of the semiconductor substrate to form a plurality of N-type doping areas on the first surface of the semiconductor substrate, the N-type doping areas and the P-type well area form an initial sensor layer, a first surface of the initial sensor layer is the first surface of the semiconductor substrate, and the initial sensor layer has a second surface opposite to the first surface; the substrate  200  is formed on the first surface of the initial sensor layer; and, grinding the second surface of the initial sensor layer after the substrate  200  is formed until the N-type doping areas are exposed to form the sensor layer  201 . 
     In other embodiments, when the silicon substrate is in an eigenstate, the P-type ions are injected from the first surface of the silicon substrate, to form the P-type well area on the first surface of the silicon substrate; the N-type ions are injected onto the first surface of the silicon substrate to form a plurality of N-type doping areas in the P-type well area, the N-type doping areas and the P-type well area form the initial sensor layer, a first surface of the initial sensor layer is the first surface of the semiconductor substrate, and the initial sensor layer also has a second surface opposite to the first surface; the substrate is formed on the first surface of the initial sensor layer; and after the substrate is formed, the second surface of the initial sensor layer is ground until the N-type doping areas are exposed to form a sensor layer. 
     The sensor layer is patterned subsequently. 
     A process for planarizing the second surface of the initial sensor layer can be chemical mechanical planarization (CMP) process. 
     A photoelectric diode  202  is formed between the P-type well area and one N-type doping area; and the sensor layer  201  comprises a plurality of N-type doping areas therein, therefore the sensor layer  201  comprises a plurality of photoelectric diodes  202 . 
     A material of the dielectric layer maybe silicon oxide; and a forming process of the dielectric layer can be a chemical vapor deposition (CVD) process or a physical vapor deposition (PVD) process. The dielectric layer has an electric interconnection structure, and the electric interconnection structure can realize the required electric connection between the image sensor and an external circuit. 
     A material of the supporting substrate is a semiconductor material, and a forming process of the supporting substrate can be a selective epitaxial deposition process. 
     After the sensor layer  201  is formed, the forming method comprises: forming an isolation structure on the surface of the sensor layer  201 . In the present embodiment, the isolation structure comprises: a first isolation layer disposed on a surface of the sensor layer  201  and a plurality of second isolation layers disposed on a surface of the first isolation layer and separated from one another. The specific forming steps of the isolation structure are illustrated in  FIG. 3  to  FIG. 4 . 
     Referring to  FIG. 3 , a passivation layer  203  is formed on a surface of the sensor layer  201 ; a first isolation layer  204  is formed on the passivation layer  203 ; and a metal grid  205  is formed on a surface of the first isolation layer  204  in the second zone B. 
     In the present embodiment, after the sensor layer  201  is formed, and prior to the forming of the first isolation layer  204 , the forming method further comprises: the passivation layer  203  is formed on a surface of the sensor layer  201 . In other embodiments, the first isolation layer is directly formed on the surface of the sensor layer. 
     A forming process of the passivation layer  203  can be a chemical vapor deposition process. A material of the passivation layer  203  can be silicon nitride, and the passivation layer  203  is used for protecting the sensor layer  201  when the first isolation layer  204  is subsequently formed. 
     A material of the first isolation layer  204  comprises: silicon oxide, silicon nitride or silicon oxynitride. A forming process of the first isolation layer  204  comprises a chemical vapor deposition process or a physical vapor deposition process. The first isolation layer  204  is used for isolating the sensor layer  201  from a color filter lenses formed subsequently. 
     In the present embodiment, after the first isolation layer  204  is formed, and prior to the formation of the second isolation layer, a metal grid  205  is formed. In other embodiments, after the first isolation layer is formed, the second isolation layer is directly formed on a surface of the first isolation layer without forming the metal grid. 
     In the present embodiment, forming steps of the metal grid  205  comprise: forming a metal grid membrane on the first isolation layer  204 , the metal grid membrane has a second patterning layer, which exposes a top surface of the metal grid membrane in the first zone A; and etching the metal grid membrane with the second patterning layer being used as a mask until the top surface of the first isolation layer  204  is exposed, thereby forming the metal grid  205 . 
     A material of the metal grid membrane is metal, and correspondingly, a material of the metal grid  205  is metal. In the present embodiment, the material of the metal grid membrane is aluminum, and correspondingly, the material of the metal grid  205  is aluminum. In other embodiments, the material of the metal grid membrane is aluminum doped with a little copper; and correspondingly, the material of the metal grid is the combination of aluminum and copper. 
     In the present embodiment, a forming process of the metal grid membrane is a physical vapor deposition process. In other embodiments, a formation process of the metal grid membrane is a chemical vapor deposition process. 
     The second lithographic layer is used for defining a pattern and a position of the metal grid  205 . 
     In the present embodiment, the second lithographic layer is an exposed patterning photoresist layer. The second patterning layer exposes a surface of the metal grid membrane in the first zone A, and then the metal grid  205  formed subsequently is disposed on a surface of the first isolation layer  204  in the second zone B, so that the formed metal grid  205  sufficiently utilizes a space between the adjacent photoelectric diodes  202  without increasing the size of the formed image sensor. 
     Functions of the metal grid  205  comprise: on one hand, the metal grid  205  can reflect the incident light; on the other hand, the metal grid  205  can prevent the incident light from entering the adjacent color filter lens from one color filter lens, and the incident light can return onto the photoelectric diode  202  corresponding to the color filter lens, so that the quantum loss can be avoided while the cross talk is avoided, thereby improving the photoelectric conversion efficiency. 
     Referring to  FIG. 4 , the second isolation layer  206  is formed on a surface of the first isolation layer  204  and on a side wall of the metal grid  205 , and the top of the second isolation layer  206  exposes a top surface of the metal grid  205 . 
     Forming steps of the second isolation layer  206  comprise: forming a second isolation membrane on the surface of the first isolation layer  204  and on the side wall and the top surface of the metal grid  205 ; flattening the second isolation membrane until the top surface of the metal grid  205  is exposed to form the second isolation layer  206 . 
     A material of the second isolation membrane comprises silicon oxide, silicon nitride or silicon oxynitride, and correspondingly, a material of the second isolation layer  206  comprises silicon oxide, silicon nitride or silicon oxynitride. 
     A forming process of the second isolation membrane comprises a chemical vapor deposition process. A process for flattening the second isolation membrane comprises: a chemical mechanical grinding process, and the second isolation layer  206  is used for isolating the sensor layer  201  and the color filter lens formed subsequently. 
     Referring to  FIG. 5 , a barrier film  207  is formed on a surface of the second isolation layer  206 ; and a first patterning layer  220  is formed on a surface of the barrier film  207  in the second zone B. 
     A material of the barrier film  207  is a low refractive index material. In the present embodiment, the material of the barrier film  207  is SiO 2  In other embodiments, the material of the barrier film may be MgF 2 , Al 2 O 3  or Ti 3 O 5 . 
     In the present embodiment, the reason for selecting SiO 2  as the material of the barrier film  207  lies in that SiO 2  does not act with water or halogens except for fluorine and hydrogen fluoride as well as sulfuric acid, nitric acid, perchloric acid(except for hot thick phosphoric acid), the chemical property of SiO 2  is relatively stable, so that the performance of the SiO 2  serving as the barrier film  207  is relatively stable. The barrier film  207  is used for subsequently forming the barrier layer, therefore, the performance of the barrier layer is stable, the capacity of the barrier layer for blocking the passing of the incident light is relatively high, and the incident light can be prevented from entering one color filter lens adjacent to a color filter lens from which the incident light enters to cause crosstalk. 
     The refractive index of a material of the barrier film  207  is 1.2 to 1.65. The barrier film  207  is used for subsequently forming the barrier layer; therefore, the refractive index of the material of the barrier film  207  determines the refractive index of the barrier layer formed subsequently. 
     A forming process of the barrier film  207  comprises: a chemical vapor deposition process or a physical vapor deposition process. 
     The first patterning layer  220  is used for defining a pattern and a position of the subsequent barrier layer. 
     In the present embodiment, the first patterning layer  220  is an exposed patterning photoresist layer. The first patterning layer  220  is disposed on a surface of the barrier film  207  in the second zone B, the barrier layer formed subsequently is disposed in the second zone B, and the formed barrier layer sufficiently utilizes the space between the adjacent photoelectric diodes  202  without increasing the size of the formed image sensor. 
     Please refer to  FIG. 6 , the first patterning layer  220  (as shown in  FIG. 5 ) is taken as a mask to etch the barrier film  207  (as shown in  FIG. 5 ) until the second isolation layer  206  is exposed, and the barrier layer  208  is formed in the second zone B; and after the barrier layer  208  is formed, the first patterning layer  220  is removed. 
     A process for etching the barrier film  207  by using the first patterning layer  220  as the mask comprises: one or a combination of a dry-method etching process and a wet-method etching process. 
     The first patterning layer  220  is used for defining a pattern and a position of the barrier layer  208 . Since the first lithographic layer  220  is disposed in the second zone B, the formed barrier layer  208  is disposed in the second zone B. 
     Moreover, the barrier film  207  is used for forming the barrier layer  208 . In the present embodiment, the material of the barrier layer  208  is SiO 2 . In other embodiments, the material of the barrier layer comprises: MgF 2 , Al 2 O 3  or Ti 3 O 5 . 
     Moreover, the refractive index of the material of the barrier layer  208  is 1.2 to 1.65. The barrier layer  208  comprises a first side  11  and a second side  12  opposite to each other in a direction parallel to a surface of the substrate  200 , and the first side  11  and the second side  12  of the barrier layer  208  subsequently cover a side wall of the color filter lens. 
     The significance of selecting the material of the barrier layer  208  to have such refractive index is illustrated by taking incident light irradiated on an interface between the barrier layer  208  and the color filter lens at the first side  11  of the barrier layer  208  as an example. If the refractive index of the barrier layer  208  is smaller than 1.2, the incident light irradiated on the interface between the barrier layer  208  and the color filter lens at the first side  11  of the barrier layer  208  still easily penetrates through the barrier layer  208 , then enters the color filter lens at the first side  11  of the barrier layer  208 , and finally irradiates on the photoelectric diode  202  corresponding to the color filter lens at the first side  11  of the barrier layer  208  after being filtered by the color filter lens at the first side  11  of the barrier layer  208 , thereby leading to the cross talk of the back-side illumination CMOS image sensor and influencing accuracy and stability of the photoelectric conversion. If the refractive index of the material of the barrier layer  208  is greater than 1.65, the light which is subsequently irradiated on the interface between the barrier layer  208  and the first side  11  of the barrier layer  208  easily generates total reflection, the total reflection light is easily irradiated on the photoelectric diode  202  corresponding to the color filter lens at the second side  12  of the barrier layer  208  after being filtered by the color filter lens, therefore, optical cross talk also likely occurs, thereby influencing accuracy and stability of the photoelectric conversion. 
     Referring to  FIG. 7  and  FIG. 8 ,  FIG. 8  is an enlarged view of area  1  of  FIG. 7 . Two color filter lenses  209   a  and  209   b  are formed on the surface of the second isolation layer  206  in the first zone A, and the color filter lenses  209   a  and  209   b  cover both side walls of the barrier layer  208 ; and a micro lens structure  210  is formed on the surface of each color filter lens  209   a  or  209   b.    
     Both the color filter lenses  209  and the photoelectric diodes  202  are disposed aligned to the first zone of the sensor layer  201 . 
     The color filter lenses  209  may be red color filter lens  209   a,  green color filter lens  209   b  or blue color filter lens  209   c . Moreover, color filter lenses  209  of one color are formed on a surface of the second isolation layer  206  on one photoelectric diode  202 , and light entering the color filter lens  209  can be filtered by the color filter lenses  209  of one color, so that the incident light irradiated on the photoelectric diode  202  is monochromatic light. 
     The micro lens structure  210  is used for focusing image light, so that incident light passing through one micro lens structure  210  can be irradiated onto the photoelectric diode  202  under the micro lens structure  210 . 
     Since the barrier layer  208  is provided between the adjacent color filter lenses  209 , the barrier layer  208  can sufficiently prevent the incident light from entering an adjacent color filter lens  209  from a color filter lens  209 , thereby avoiding the cross talk. Specifically, referring to  FIG. 8 , taking the green color filter lens  209   b  as an example, light D is irradiated on an interface between the green color filter lens  209   b  and the barrier layer  208  through the micro lens structure  210 . If no barrier layer  208  is provided, the light D enters the red color filter lens  209   a  along a dotted line direction, and is finally irradiated onto the photoelectric diode  202  corresponding to the red color filter lens  209   a  after being filtered by the red color filter lens  209   a,  which likely cause the cross talk of the back-side illumination CMOS image sensor. If the barrier layer  208  is formed between the adjacent photoelectric diodes  202 , and the refractive index of the barrier layer  208  is 1.2 to 1.65, the light D will be refracted along a solid line direction, and the light D will not enter the red color filter lens  209   a;  and therefore, the optical cross talk can be reduced, and the image sensor is accurate and stable in performance. 
     The present disclosure further provides a semiconductor structure formed by adopting the above method. Referring to  FIG. 7 , the semiconductor structure comprises: 
     a substrate  200 ; 
     a sensor layer  201  disposed on a surface of the substrate  200 , wherein the sensor layer  201  comprises a plurality of first zones A and second zones B between the adjacent first zones A along a direction parallel to the surface of the substrate  200 , and the sensor layer  201  in the first zone A has a photoelectric diode  202 ; 
     an isolation structure disposed on a surface of the sensor layer  201 ; 
     a color filter lens  209  disposed on a surface of the isolation structure in the first zone A; 
     a barrier layer  208  disposed on a surface of the isolation layer in the second zone B, the barrier layer  208  covers a side wall of the color filter lens  209 , and a refractive index of a material of the barrier layer  208  is smaller than a refractive index of a material of the color filter lens  209 ; and 
     a lens structure  210  disposed on a surface of the color filter lens  209 . 
     A refractive index of the barrier layer  208  is 1.2 to 1.65. The material of the barrier layer  208  comprises: SiO2, MgF2, Al2O3 or Ti3O5. 
     A surface of the isolation structure on one photoelectric diode  202  has one color filter lens  209 , and the color filter lens  209  disposed on a surface of the isolation structure on one photoelectric diode  202  is a red color filter lens, a green color filter lens or a blue color filter lens. 
     The technical solution of the present disclosure has the following benefits: 
     In the image sensor provided in the present disclosure, light in different angles enters the color filter lens in a single pixel zone through a micro lens structure. Since the barrier layer is provided between the adjacent color filter lenses, and the refractive index of the barrier layer material is smaller than the refractive index of the color filter lens material, the barrier layer can prevent the light irradiated on a junction between the color filter lens and the barrier layer from entering the adjacent color filter lens, so that the incident light entering the color filter lens in the single pixel area can completely irradiate on the sensor layer corresponding to the pixel zone, thereby avoiding cross talk, and enabling the image sensor to be accurate and stable in performance 
     Although the present disclosure is disclosed as above, the present disclosure is not limited thereto. Various changes and modifications may be made by any person skilled in the art without departing from the spirit and scope of the present disclosure, and therefore the protection scope of the present disclosure shall be subjected to the scope defined by the claims.