CN112530981A - Image sensor capable of reducing infrared reflection and preparation method thereof - Google Patents
Image sensor capable of reducing infrared reflection and preparation method thereof Download PDFInfo
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Abstract
The invention provides an image sensor capable of reducing infrared reflection, which comprises a semiconductor substrate, an interlayer insulating layer, a first oxide layer, a first anti-reflection coating, a flat layer and a micro lens. The semiconductor substrate includes a pixel region and an isolation region, the pixel region including a photoelectric conversion portion and a charge transfer portion; the interlayer insulating layer is arranged on the front surface of the semiconductor substrate, and a metal wiring structure is arranged on the interlayer insulating layer; the first oxidation layer is arranged on the back surface of the semiconductor substrate; a first anti-reflective coating disposed on the first oxide layer; the planarization layer is arranged on the first anti-reflection coating and is used for planarizing the surface of the first anti-reflection coating; the micro lens is arranged on the flat layer and used for gathering incident light. The invention also provides a preparation method of the image sensor.
Description
Technical Field
The present invention relates to an image sensor, and more particularly, to an image sensor capable of reducing infrared reflection and a method for manufacturing the same.
Background
The image capturing apparatus includes an image sensor and an imaging lens. The imaging lens focuses light onto an image sensor to form an image, and the image sensor converts an optical signal into an electrical signal. The image capture device outputs electrical signals to other components of the host system. The image capture device and other components of the host system form an image sensor system or imaging system. The application of image sensors has become widespread and can be applied to various electronic systems such as mobile devices, digital cameras, medical devices or computers.
A typical image sensor includes a two-dimensional array of a plurality of light-sensitive elements ("pixels"). Such image sensors may be configured to produce color images by forming a Color Filter Array (CFA) over the pixels. The technology for fabricating image sensors, and particularly complementary metal oxide semiconductor ("CMOS") image sensors, continues to advance rapidly. For example, the demands for high resolution and low power consumption have facilitated further miniaturization and integration of such image sensors. However, miniaturization comes at the expense of pixel photosensitivity and dynamic range, and new approaches are needed to address this problem.
As the pixel size decreases, the total light absorption depth within the substrate becomes insufficient for some light, especially long wavelength light. This is particularly a problem for image sensors employing backside illuminated (BSI) technology when the image light is incident on the backside of the sensor substrate. In back-illuminated (BSI) technology, the sensor silicon substrate may be only 2 microns thick, which is sufficient to absorb blue light but very insufficient to absorb red light, which may require 10 microns thick to be fully absorbed. The existing image sensor has high reflectivity of infrared light when the wavelength of incident light is about 940nm, which can be up to more than 22%, so that the stray light is serious during imaging, thereby influencing the use.
Disclosure of Invention
The following description sets forth the contributions of the present invention.
The invention provides an image sensor capable of reducing infrared reflection, comprising:
a semiconductor substrate including a pixel region including a photoelectric conversion portion and a charge transfer portion, and an isolation region for isolating two adjacent pixel regions;
the interlayer insulating layer is arranged on the front surface of the semiconductor substrate, and a metal wiring structure is arranged on the interlayer insulating layer and used for connecting circuit components;
the first oxidation layer is arranged on the back surface of the semiconductor substrate and is used as an insulating medium between components on the semiconductor substrate;
the first anti-reflection coating is arranged on the first oxidation layer and used for reducing the reflectivity of incident light;
a planarization layer disposed on the first anti-reflective coating layer for planarizing a surface of the first anti-reflective coating layer; and
and a microlens disposed on the planarization layer to condense incident light to correspond to the photoelectric conversion part in the pixel region.
Optionally, the first anti-reflective coating is a color filter.
Optionally, the first anti-reflective coating is a blue optical dye.
Optionally, the refractive index of the first anti-reflection coating ranges from 1.7 to 1.8.
Optionally, the thickness of the first anti-reflection coating is 0.66-0.875 um.
Optionally, the image sensor further comprises a second anti-reflective coating disposed between the first anti-reflective coating and the first oxide layer.
Optionally, the material of the second anti-reflection coating is SiN.
Optionally, the refractive index of the second anti-reflection coating is in a range of 1.8-1.9.
Optionally, the thickness of the second anti-reflection coating is in a range of 0-0.13 um.
Optionally, the image sensor is a black and white backside illuminated image sensor.
Optionally, the image sensor further comprises a first dielectric layer, a second dielectric layer and a second oxide layer; the second oxide layer is disposed on the semiconductor substrate, the first dielectric layer is disposed on the second oxide layer, and the second dielectric layer is disposed between the first dielectric layer and the first oxide layer.
The invention also provides a manufacturing method of the image sensor capable of reducing infrared reflection, which comprises the following steps:
forming a pixel region and an isolation region within a semiconductor substrate, the pixel region including a photoelectric conversion portion and a charge transfer portion;
forming an interlayer insulating layer on the front surface of the semiconductor substrate and forming a metal wiring structure on the interlayer insulating layer for connecting circuit components;
forming a first oxidation layer on the back surface of the semiconductor substrate to serve as an insulating medium between each component on the semiconductor substrate;
forming a first anti-reflection coating on the first oxide layer;
forming a planarization layer on the first anti-reflective coating layer to planarize a surface of the first anti-reflective coating layer; and
forming a microlens on the planarization layer to collect incident light corresponding to the photoelectric conversion portion in the pixel region.
Optionally, the first anti-reflective coating is a color filter.
Optionally, the first anti-reflective coating is a blue optical dye.
Optionally, the refractive index of the first anti-reflection coating ranges from 1.7 to 1.8.
Optionally, the thickness of the first anti-reflection coating is 0.66-0.875 um.
Optionally, the method further comprises the steps of: a second anti-reflective coating layer is formed between the first oxide layer and the first anti-reflective coating layer.
Optionally, the material of the second anti-reflection coating is SiN.
Optionally, the refractive index of the second anti-reflection coating is in a range of 1.8-1.9.
Optionally, the thickness of the second anti-reflection coating is in a range of 0-0.13 um.
Optionally, the image sensor is a black and white backside illuminated image sensor.
Optionally, the method for manufacturing the image sensor further comprises the following steps:
forming a second oxide layer on the semiconductor substrate;
forming a first dielectric layer on the second oxide layer; and
a second dielectric layer is formed between the first dielectric layer and the first oxide layer.
Other features and advantages of the present invention will become more apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the advantages of the invention.
Drawings
FIG. 1 is a diagram illustrating light reflection in an image sensor according to the present invention;
FIG. 2a is a schematic structural diagram of an image sensor according to an embodiment of the present invention;
FIG. 2b is a schematic structural diagram of an image sensor according to an embodiment of the present invention;
FIG. 3a is a schematic structural diagram of an image sensor according to another embodiment of the present invention;
FIG. 3b is a schematic structural diagram of an image sensor according to another embodiment of the present invention;
FIG. 4a is a flow chart of a method of fabricating an image sensor according to one embodiment of the present invention;
FIG. 4b is a flow chart of a method of fabricating an image sensor according to one embodiment of the present invention;
FIG. 5a is a flow chart of a method for fabricating an image sensor according to another embodiment of the present invention, and
fig. 5b is a flowchart of a method for manufacturing an image sensor according to another embodiment of the invention.
Detailed Description
The figures illustrate the present invention, an image sensor capable of reducing infrared reflection and a method for fabricating the same. Various embodiments of an image sensor are disclosed herein. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring particular content. One substrate may have a front side and a back side. Any process operation from the front side may be considered a front side operation and from the back side may be considered a back side operation. Structures or devices such as photodiodes and associated transistors may be formed on the front side of the substrate. An alternating layer dielectric stack including a metal wiring layer and a conductive layer is formed on the front surface of the substrate.
"connected" and "coupled" as used herein are defined as follows. "connection" is used to describe a direct connection between two circuit components, such as metal lines formed according to common integrated circuit processing techniques. In contrast, "coupled" is used to describe a direct or indirect connection between two circuit components. For example, two coupling components may be connected directly by a metal line or indirectly by an intervening circuit component (e.g., a capacitor, a resistor, or a source or drain of a transistor).
Fig. 1 shows a schematic diagram of light reflection in an image sensor of the present invention. The invention utilizes the principle of optical interference cancellation, and the optical path of the reflected light of each layer after combination meets the requirement of interference cancellation to reduce the reflectivity of the incident light R0, namely reduce the generation of the reflected light R1, R2 and R3, and improve the light sensitivity of the image sensor by setting different refractive index materials of each layer of the image sensor and optimizing the structure thickness of each layer.
Fig. 2a shows a schematic structural diagram of an image sensor 200 according to an embodiment of the present invention. The image sensor 200 includes an interlayer insulating layer 210, a semiconductor substrate 220, a first oxide layer 230, a first anti-reflective coating 240, a planarization layer 250, and a microlens 260. The interlayer insulating layer 210 is disposed on the front surface of the semiconductor substrate 210, and a metal wiring structure 212 is disposed thereon for connecting circuit components. A pixel region 222 and an isolation region 224 are disposed on the semiconductor substrate 220. The pixel region 222 includes a photoelectric conversion portion for converting incident light into photoelectric charges and a charge transfer portion, such as a photodiode and a plurality of transistors, for reading and transferring out signal charges from the photoelectric conversion portion. The transistor is not shown in fig. 2, but the gate 214 of the transistor is shown in the interlayer insulating layer 210 to indicate the presence of the transistor. Adjacent pixel regions 222 are isolated by the isolation structure 224. The isolation structure 224 is an oxide region. In one embodiment, the Isolation structure 224 is STI (Shallow Trench Isolation), and in another embodiment, the Isolation structure 224 is LOCOS (Local Oxidation of Silicon), and the Isolation structure 224 is used to reduce signal crosstalk and leakage current between the pixel regions 222.
The first oxide layer 230 is disposed over the semiconductor substrate 220. In one embodiment, the first oxide layer 230 is silicon dioxide SiO2, which is used as an insulating dielectric layer between devices on the semiconductor substrate 220. In one embodiment, the first oxide layer 230 is a planar oxide layer. The first anti-reflective coating 240 is disposed above the first oxide layer 230 for reducing the reflectivity of incident light, especially infrared light. In one embodiment, the first anti-reflective coating 240 is a color filter. In one embodiment, the first anti-reflective coating 240 is a blue optical dye. In one embodiment, the refractive index of the first anti-reflective coating 240 ranges from 1.7 to 1.8. In one embodiment, the thickness of the first anti-reflective coating 240 ranges from 0.66 to 0.875 μm. In one embodiment, the first anti-reflective coating 240 may cover only the photodiode region in the pixel region 222, and other regions may be removed by etching. The planarization layer 250 is disposed above the first anti-reflective coating 240 for planarizing a height difference of the surface of the first anti-reflective coating 240, and the microlens 260 is disposed above the planarization layer 250 for condensing incident light to the photodiode in the pixel region 222 for photoelectric conversion. The micro lens 260 is a transparent polymer material having a certain height and is disposed on the planarization layer 250 in a hemispherical shape to collect incident light. In one embodiment, the microlenses 260 and the planarization layer 250 are both of a light-transmissive resin material. The first anti-reflective coating 240 and the oxide layer 230 are both transparent materials so that incident light can penetrate to reach the photodiode on the semiconductor substrate 220. By using the material characteristics of the first anti-reflective coating 240 and setting different thicknesses of the layers, the amount of reflection of incident light of the photodiode is reduced and the sensitivity of the photodiode is improved. In one embodiment, the height of the microlens 260 is 1.35um, the thickness of the planarization layer 250 is 1.05um, the thickness of the first anti-reflective coating is 0.85um, and the thickness of the first oxide layer 230 is 0.61 um. By such an arrangement, the incident light reflectance can be reduced to 9.4%.
In another embodiment, as shown in fig. 2b, the image sensor 200 further comprises a second oxide layer 232, a first dielectric layer 234, and a first dielectric layer 236. The second oxide layer 232 is disposed on the semiconductor substrate 220, the first dielectric layer 234 is disposed on the second oxide layer 232, and the second dielectric layer 236 is disposed over the first dielectric layer 234. In one embodiment, the second Oxide layer 232 is a SiO2 material, the first dielectric layer 234 is a TAO (Tantalum Oxide) material, and the second dielectric layer 236 is a HFO (Hafnium Oxide) material. The combination of the second oxide layer 232, the first dielectric layer 234 and the second dielectric layer 236 is used to further reduce dark current generated by each device on the semiconductor substrate 220. In one embodiment, the image sensor 200 is a black and white backside illuminated image sensor.
Fig. 3a shows a schematic structural diagram of an image sensor 300 according to an embodiment of the present invention, where the image sensor 300 includes an interlayer insulating layer 310, a semiconductor substrate 320, a first oxide layer 330, a first anti-reflective coating 340, a second anti-reflective coating 342, a planarization layer 350, and a microlens 360. The interlayer insulating layer 210 is disposed on the front surface of the semiconductor substrate 310, and a metal wiring structure 312 is disposed thereon for connecting circuit components. A pixel region 322 and an isolation region 324 are disposed on the semiconductor substrate 320. The pixel region 322 includes a photoelectric conversion portion for converting incident light into photoelectric charges and a charge transfer portion, such as a photodiode and a plurality of transistors, for reading and transferring out signal charges from the photoelectric conversion portion. The transistor is not shown in fig. 3a, but the gate 314 of the transistor is shown in the interlayer insulating layer 310 to indicate the presence of the transistor. The adjacent pixel regions 322 are isolated by the isolation structure 324. The first oxide layer 330 is disposed over the semiconductor substrate 220. The first oxide layer 330 is silicon dioxide SiO2, and is used as an insulating medium layer between components on the semiconductor substrate 320. In one embodiment, the first oxide layer 330 is a planar oxide layer.
Unlike the image sensor 200 in fig. 2a, a second anti-reflective coating 342 is provided in the image sensor 300 in fig. 3 a. The second anti-reflective coating layer 342 is disposed between the first anti-reflective coating layer 340 and the first oxide layer 330. In one embodiment, the material of the second anti-reflective coating layer 342 is SiN. The refractive index range of the second anti-reflection coating 342 is 1.8-1.9. The thickness range of the second anti-reflection coating 342 is 0-0.13 um. In one embodiment, the first anti-reflective coating 340 and the first anti-reflective coating 342 may cover only the photodiode region in the pixel region 322, and the other regions may be removed by etching. The planarization layer 350 is disposed on the first anti-reflective coating 340 for planarizing a height difference of the surface of the first anti-reflective coating 340, and the microlens 360 is disposed on the planarization layer 350 for condensing incident light to a photodiode in the pixel region 322 within the semiconductor substrate 320 for photoelectric conversion. By using the material properties of the first anti-reflective coating 340 and the second anti-reflective coating 342 and setting the different thicknesses of the layers, the amount of reflection of the incident light of the photodiode is reduced and the sensitivity of the photodiode is improved. In one embodiment, the height of the microlens 360 is 0.95um, the thickness of the planarization layer 350 is 1.05um, the thickness of the first anti-reflection coating is 0.68um, the thickness of the second anti-reflection coating is 0.12um, and the thickness of the first oxidation layer is 0.6 um. By such an arrangement, the incident light reflectance can be reduced to 8.5%.
In another embodiment, as shown in fig. 3b, the image sensor 300 further comprises a second oxide layer 332, a first dielectric layer 334, and a second dielectric layer 336. The second oxide layer 332 is disposed over the semiconductor substrate 320, the first dielectric layer 334 is disposed over the second oxide layer 332, and the second dielectric layer 336 is disposed over the first dielectric layer 334. In one embodiment, the second Oxide layer 332 is a SiO2 material, the first dielectric layer 334 is a TAO (Tantalum Oxide) material, and the second dielectric layer 336 is a HFO (Hafnium Oxide) material. The combination of the second oxide layer 332, the first dielectric layer 334 and the second dielectric layer 336 is used to further reduce dark current generated by each device on the semiconductor substrate 320. In one embodiment, the image sensor 300 is a black and white backside illuminated image sensor.
Fig. 4a shows a schematic flow chart of a method 400 for manufacturing an image sensor according to an embodiment of the invention. The method 400 for manufacturing the image sensor includes the following steps.
Step 410: a pixel region and an isolation structure are formed in a semiconductor substrate.
The pixel region includes a photoelectric conversion portion for converting incident light into photoelectric charges and a charge transfer portion, such as a photodiode and a plurality of transistors, which reads and transfers out signal charges from the photoelectric conversion portion. The adjacent pixel regions are isolated by the isolation structure. The isolation structure is an oxide region. In one embodiment, the Isolation structure is STI (Shallow Trench Isolation), and in another embodiment, the Isolation structure is LOCOS (Local Oxidation of Silicon), and the Isolation structure is used to reduce signal crosstalk and leakage current between pixel regions.
Step 420: an interlayer insulating layer is provided on the front surface of the semiconductor substrate and a metal wiring structure is provided thereon. The metal wiring structure is used for connecting circuit components.
Step 430: a first oxide layer is provided on the back surface of the semiconductor substrate.
The first oxide layer is formed on the back surface of the semiconductor substrate. In one embodiment, the first oxide layer is SiO2, and is used as an insulating medium layer between components on the semiconductor substrate. In one embodiment, the first oxide layer is a planar oxide layer.
Step 440: a first anti-reflective coating is formed over the first oxide layer.
The first anti-reflective coating is used to reduce the reflectivity of incident light, particularly infrared light. In one embodiment, the first anti-reflective coating is a color filter. In one embodiment, the first antireflective coating is a blue optical dye. In one embodiment, the refractive index of the first anti-reflective coating ranges from 1.7 to 1.8. In one embodiment, the thickness of the first anti-reflective coating ranges from 0.66 to 0.875 um. In one embodiment, the first anti-reflective coating may cover only the photodiode region in the pixel region, and the other regions may be removed by etching.
Step 450: a planarization layer is formed on the first anti-reflective coating.
The planarization layer is formed above the first anti-reflection coating layer and is used for planarizing the height difference of the surface of the first anti-reflection coating layer.
Step 460: forming a microlens over the planarization layer.
The microlens is disposed on the planarization layer for condensing incident light to a photodiode in a pixel region within a semiconductor substrate for photoelectric conversion. The micro lens is made of a transparent high polymer material, has a certain height, is arranged on the flat layer in a hemisphere mode, and is used for gathering incident light. In one embodiment, the microlenses and the planarization layer are each a light-transmissive resin material. The first anti-reflective coating 240 and the oxide layer are also light transmissive materials so that incident light can penetrate to reach the photodiode on the semiconductor substrate.
By using the material characteristics of the first anti-reflection coating and setting different thicknesses of each layer, the reflection quantity of incident light of the photodiode is reduced and the light sensitivity of the photodiode is improved. In this embodiment, the height of microlens is 1.35um, the thickness of planarization layer is 1.05um, the thickness of first antireflection coating is 0.85um, the thickness of first oxide layer is 0.61 um. By such an arrangement, the incident light reflectance can be reduced to 9.4%.
Fig. 4b shows a flow chart of a method 400 for manufacturing an image sensor according to an embodiment of the invention. The following steps are also included between steps 420 and 430.
Step 432: a second oxide layer is formed on the back surface of the semiconductor substrate.
Step 434: a first dielectric layer is formed over the second oxide layer.
Step 436: a second dielectric layer is formed between the first dielectric layer and the first oxide layer.
In one embodiment, the second Oxide layer is a SiO2 material, the first dielectric layer is a TAO (Tantalum Oxide) material, and the second dielectric layer is a HFO (Hafnium Oxide) material. The second oxide layer, the first dielectric layer and the second dielectric layer are combined to further relieve dark current generated by each device on the semiconductor substrate. In one embodiment, the image sensor is a black and white backside illuminated image sensor.
Fig. 5a shows a schematic flow chart of a method 500 for manufacturing an image sensor according to an embodiment of the present invention. The method 500 for manufacturing the image sensor includes the following steps.
Step 510: a pixel region and an isolation structure are formed in a semiconductor substrate.
The pixel region includes a photoelectric conversion portion for converting incident light into photoelectric charges and a charge transfer portion, such as a photodiode and a plurality of transistors, which reads and transfers out signal charges from the photoelectric conversion portion. The adjacent pixel regions are isolated by the isolation structure.
Step 520: an interlayer insulating layer is provided on the front surface of the semiconductor substrate and a metal wiring structure is provided thereon. The metal wiring structure is used for connecting circuit components on the semiconductor substrate.
Step 530: a first oxide layer is provided on the back surface of the semiconductor substrate.
The first oxide layer is formed on the back surface of the semiconductor substrate. In one embodiment, the first oxide layer is SiO2, and is used as an insulating medium layer between components on the semiconductor substrate. In one embodiment, the first oxide layer is a planar oxide layer.
Step 542: a second antireflective coating is disposed on the first oxide layer.
In one embodiment, the second antireflective coating is SiN. The refractive index range of the second anti-reflection coating is 1.8-1.9. The thickness of the second anti-reflection coating is 0-0.13 um.
Step 540: a first anti-reflective coating is disposed over the second anti-reflective coating.
The first anti-reflective coating is used to reduce the reflectivity of incident light, particularly infrared light. In one embodiment, the first anti-reflective coating is a color filter. In one embodiment, the first antireflective coating is a blue optical dye. In one embodiment, the refractive index of the first anti-reflective coating ranges from 1.7 to 1.8. In one embodiment, the thickness of the first anti-reflective coating ranges from 0.66 to 0.875 um. In one embodiment, the first anti-reflective coating and the second anti-reflective coating may cover only the photodiode region in the pixel region, and the other regions may be removed by etching.
Step 550: a planarization layer is disposed over the first anti-reflective coating.
The planarization layer is formed above the first anti-reflection coating layer and is used for planarizing the height difference of the surface of the first anti-reflection coating layer.
Step 560: a microlens is disposed over the planarization layer.
The microlens is disposed on the planarization layer for condensing incident light to a photodiode in a pixel region within a semiconductor substrate for photoelectric conversion. The micro lens is made of a transparent high polymer material, has a certain height, is arranged on the flat layer in a hemisphere mode, and is used for gathering incident light. In one embodiment, the microlenses and the planarization layer are each a light-transmissive resin material. The first anti-reflection coating and the oxidation layer are also light-transmitting materials so that incident light can penetrate and reach the photodiode on the semiconductor substrate.
By using the material characteristics of the first anti-reflection coating and setting different thicknesses of each layer, the reflection quantity of incident light of the photodiode is reduced and the light sensitivity of the photodiode is improved. In this embodiment, the height of microlens is 0.95um, the thickness of planarization layer is 1.05um, the thickness of first antireflection coating is 0.68um, the thickness of second antireflection coating is 0.12um, the thickness of first oxide layer is 0.61 um. By such an arrangement, the incident light reflectance can be reduced to 8.5%.
Fig. 5b shows a schematic flow chart of a method 500 for manufacturing an image sensor according to an embodiment of the invention. The following steps are also included between steps 520 and 530.
Step 532: a second oxide layer is provided on the back surface of the semiconductor substrate.
Step 534: a first dielectric layer is disposed over the second oxide layer.
Step 536: a second dielectric layer is disposed on the first dielectric layer.
In one embodiment, the second Oxide layer is a SiO2 material, the first dielectric layer is a TAO (Tantalum Oxide) material, and the second dielectric layer is a HFO (Hafnium Oxide) material. The second oxide layer, the first dielectric layer and the second dielectric layer are combined to further relieve dark current generated by each device on the semiconductor substrate. In one embodiment, the image sensor is a black and white backside illuminated image sensor.
In summary, the present invention provides an image sensor capable of reducing infrared reflection and a method for manufacturing the same, in which a first anti-reflection coating and a second anti-reflection coating are disposed between a first oxide layer on a semiconductor substrate and a planarization layer below a microlens, and by using the principle of destructive interference, the optical paths of the reflected light of each layer after combination are reduced by using different refractive index materials and optimizing the structure thickness, so as to reduce the infrared reflection and improve the sensitivity of the image sensor.
Reference throughout this specification to "one embodiment," "an embodiment," "one example" or "an example" means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment. Or an example of the present invention. Thus, the appearances of the phrases such as "in one embodiment" or "in an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments or examples. Directional terms such as "top," "down," "above," and "below" are used with reference to the orientation of the drawings as described. Furthermore, the terms "having," "including," "containing," and similar terms are defined as meaning "including" unless specifically stated otherwise. The particular features, structures, or characteristics may be included in an integrated circuit, an electronic circuit, a combinational logic circuit, or other suitable components that provide the described functionality. Additionally, it should be understood that the drawings provided herein are for illustrative purposes only of those of ordinary skill in the art and that the drawings are not necessarily drawn to scale.
The above description of illustrated examples of the present invention, including what is described in the abstract, is not intended to be exhaustive or to be limited to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications can be made without departing from the broader spirit and scope of the invention. Indeed, it should be understood that the specific example structures and materials are provided for purposes of explanation, and that other structures and materials may be used in other embodiments and examples in accordance with the teachings of the present invention. These modifications can be made to embodiments of the present invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims. Rather, the scope is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.
The present invention also provides an image sensor device including the pixel circuit described in each of the above embodiments. The image sensor device comprises a pixel circuit array which is arranged in a plurality of rows and columns and is provided in the plurality of embodiments. The image sensor device further comprises peripheral circuitry, which is mainly used for controlling and processing the output of the pixel circuits.
The examples given in the embodiments of the present invention include, but are not limited to, the explanation and illustration of the present invention as set forth herein. The above-described embodiments are for illustrative purposes only and are not to be construed as limiting the invention. Reasonable modifications and adaptations of the various embodiments of the invention are within the scope of the invention.
Claims (22)
1. An image sensor capable of reducing infrared reflection, comprising:
a semiconductor substrate including a pixel region including a photoelectric conversion portion and a charge transfer portion, and an isolation region for isolating two adjacent pixel regions;
the interlayer insulating layer is arranged on the front surface of the semiconductor substrate, and a metal wiring structure is arranged on the interlayer insulating layer and used for connecting circuit components;
the first oxidation layer is arranged on the back surface of the semiconductor substrate and is used as an insulating medium between components on the semiconductor substrate;
the first anti-reflection coating is arranged on the first oxidation layer and used for reducing the reflectivity of incident light;
a planarization layer disposed on the first anti-reflective coating layer for planarizing a surface of the first anti-reflective coating layer; and
and a microlens disposed on the planarization layer to condense incident light to correspond to the photoelectric conversion part in the pixel region.
2. The image sensor of claim 1, wherein the first anti-reflective coating is a color filter.
3. The image sensor of claim 1, wherein the first anti-reflective coating is a blue optical dye.
4. The image sensor of claim 1, wherein the first anti-reflective coating has a refractive index in a range of 1.7 to 1.8.
5. The image sensor of claim 1, wherein the first anti-reflective coating has a thickness of 0.66 to 0.875 um.
6. The image sensor of claim 1, further comprising a second antireflective coating disposed between the first antireflective coating and the first oxide layer.
7. The image sensor of claim 6, wherein the second anti-reflective coating is of a material of SiN.
8. The image sensor of claim 6, wherein the second anti-reflective coating has a refractive index in a range of 1.8 to 1.9.
9. The image sensor of claim 6, wherein the second anti-reflective coating has a thickness in a range of 0 to 0.13 um.
10. The image sensor of claim 1, wherein the image sensor is a black and white backside illuminated image sensor.
11. The image sensor of claim 1, further comprising a first dielectric layer, a second dielectric layer, and a second oxide layer between the first oxide layer and the semiconductor substrate; the second oxide layer is disposed on the semiconductor substrate, the first dielectric layer is disposed on the second oxide layer, and the second dielectric layer is disposed between the first dielectric layer and the first oxide layer.
12. A method for manufacturing an image sensor capable of reducing infrared reflection, comprising the steps of:
forming a pixel region and an isolation region within a semiconductor substrate, the pixel region including a photoelectric conversion portion and a charge transfer portion;
forming an interlayer insulating layer on the front surface of the semiconductor substrate and forming a metal wiring structure on the interlayer insulating layer for connecting circuit components;
forming a first oxidation layer on the back surface of the semiconductor substrate to serve as an insulating medium between each component on the semiconductor substrate;
forming a first anti-reflection coating on the first oxide layer;
forming a planarization layer on the first anti-reflective coating layer to planarize a surface of the first anti-reflective coating layer; and
forming a microlens on the planarization layer to collect incident light corresponding to the photoelectric conversion portion in the pixel region.
13. The method of claim 12, wherein the first anti-reflective coating is a color filter.
14. The method of claim 12, wherein the first anti-reflective coating is a blue optical dye.
15. The method of claim 12, wherein the first anti-reflective coating has a refractive index ranging from 1.7 to 1.8.
16. The method of claim 12, wherein the first anti-reflective coating has a thickness of 0.66-0.875 um.
17. The method for manufacturing an image sensor according to claim 12, further comprising the steps of: a second anti-reflective coating layer is formed between the first oxide layer and the first anti-reflective coating layer.
18. The method of claim 17, wherein the second anti-reflective coating is made of SiN.
19. The method of claim 17, wherein the second anti-reflective coating has a refractive index in a range of 1.8 to 1.9.
20. The method of claim 17, wherein the second anti-reflective coating has a thickness in a range of 0 to 0.13 um.
21. The method for manufacturing an image sensor according to claim 12, wherein the image sensor is a black-and-white back-illuminated image sensor.
22. The method for manufacturing an image sensor according to claim 12, further comprising the steps of:
forming a second oxide layer on the semiconductor substrate;
forming a first dielectric layer on the second oxide layer; and
a second dielectric layer is formed between the first dielectric layer and the first oxide layer.
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