An image sensor and a manufacturing process thereof

Abstract

The application discloses an image sensor and a manufacturing process thereof, and at least comprises the following steps: providing a substrate, the substrate is formed with a pixel area and a non-imaging area of a periphery; forming an anti-reflection layer above the non-imaging area, the anti-reflection layer covers at least part of the top of the non-imaging area; etching the anti-reflection layer to randomly roughen the surface of the anti-reflection layer; wherein the material of the anti-reflection layer at least comprises a first black light-absorbing material and a second black light-absorbing material, and the etching rate of the first black light-absorbing material is different from that of the second black light-absorbing material. The black light-absorbing materials with different etching rates are etched, the anti-reflection layer is randomly roughened on the surface through etching selection ratio, the reflection intensity in a specific direction to all directions is greatly reduced, the stray light entering the pixel area is fundamentally reduced, the generation of light spots and ghosting is avoided, and the image quality is improved.

Description

Technical Field

[0001] This invention relates to the field of image sensor technology, and more specifically to an image sensor and its manufacturing process. Background Technology

[0002] A CMOS (Complementary Metal-Oxide-Semiconductor) image sensor is a core semiconductor device that converts optical signals into electrical signals. Its core structure is mainly divided into two parts: the pixel array and the peripheral logic area. During imaging, only the "imaging light" illuminating the pixel array is a valid signal. Non-imaging light incident on the peripheral logic area, if not properly processed, can generate stray light and other optical noise, forming optical artifacts such as light spots or ghosting, severely degrading image quality. Although current mainstream technology involves forming a light-shielding layer on the peripheral logic area, incident light still reflects off these layers, meaning the light-shielding layer's handling of stray light is insufficient. Furthermore, existing light-shielding layer materials are expensive and have limitations in manufacturing processes. In addition, metal structures such as wire pads in the peripheral logic area can generate strong reflections, further contributing to stray light. Especially in autonomous driving (ADAS) applications, problematic image information generated by glare may be treated as false information, thus affecting the reliability of the recognition results.

[0003] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0004] The purpose of this invention is to effectively reduce the reflection of incident light on the surface of the non-imaging area of ​​a CMOS image sensor, thereby suppressing the generation of light spots and ghosting caused by stray light and improving the imaging quality of the image sensor.

[0005] To achieve the above objectives, the present invention provides a manufacturing process for an image sensor, comprising at least: A substrate is provided on which pixel areas and peripheral non-imaging areas are formed; An anti-reflective layer is formed above the non-imaging area, and the anti-reflective layer covers at least a portion of the top area of ​​the non-imaging area; The anti-reflective layer is etched to randomly roughen its surface. The anti-reflective layer comprises at least a first black light-absorbing material and a second black light-absorbing material, wherein the etching rates of the first black light-absorbing material and the second black light-absorbing material are different.

[0006] Optionally, the first black light-absorbing material comprises carbon black, and the second black light-absorbing material comprises organic black filler.

[0007] Optionally, the particle size of the first black light-absorbing material and the second black light-absorbing material is 40nm~100nm.

[0008] Optionally, the surface roughness of the anti-reflective layer is 100nm~300nm.

[0009] Optionally, the material of the antireflective layer may further include an adhesive resin, which may include acrylic resins or epoxy resins.

[0010] Optionally, at least one of a red filter, a blue filter, a first black light-absorbing material layer, and a second black light-absorbing material layer is further disposed between the non-imaging area and the anti-reflective layer. The red filter and / or blue filter can be used to block light, prevent reflection, reduce step differences, and prevent discoloration of the border area.

[0011] Optionally, the etching is dry etching.

[0012] Optionally, at least a silicon-containing gas and a fluorine-containing gas are introduced into the surface of the antireflective layer, and a plasma source is turned on. Under the action of the plasma, the silicon-containing gas dissociates into silicon-containing free radicals, and the fluorine-containing gas dissociates into fluorine-containing free radicals, such as C3F8. The silicon-containing free radicals react with the fluorine-containing free radicals to etch the antireflective layer.

[0013] Optionally, it also includes introducing an inert gas into the surface of the antireflective layer.

[0014] Accordingly, the present invention also provides an image sensor, which is prepared by the above-described manufacturing process.

[0015] Compared to the prior art, the beneficial effects of the present invention include at least the following: (1) In this invention, an anti-reflection layer is disposed above the non-imaging area. The anti-reflection layer comprises at least a first black light-absorbing material and a second black light-absorbing material with different etching rates. During the etching process, the first and second black light-absorbing materials are selectively removed due to their different etching rates, thereby forming a nanoscale random rough structure on the surface of the anti-reflection layer. The anti-reflection layer with a random rough structure can disrupt the specular reflection conditions of a smooth surface, significantly reducing specular reflection and causing incident light to be scattered in multiple directions on the surface of the anti-reflection layer. The scattered light is further absorbed by the first and second black light-absorbing materials. As a result, the intensity of reflected light propagating toward the pixel area can be reduced, stray light entering the pixel area can be reduced, thereby suppressing optical noise such as glare, ghosting, and double images, and improving the imaging quality of the image sensor.

[0016] (2) The anti-reflection layer of the present invention is formed of a black light-absorbing material, which can absorb incident light, scattered light, and / or reflected light. Furthermore, at least one of a red filter layer, a blue filter layer, a first black light-absorbing material layer, and a second black light-absorbing material layer can be disposed between the non-imaging area and the anti-reflection layer. Through the above structure, light of a specific wavelength band can be further absorbed or blocked, and in conjunction with the random rough structure of the anti-reflection layer surface, a combination of scattering and absorption is achieved to block light and reduce reflection, thereby further reducing the intensity of reflected light on the surface of the non-imaging area.

[0017] (3) The present invention can use conventional etching processes such as dry etching, plasma etching, reactive ion etching or ashing etching to roughen the surface of the anti-reflective layer without the need to form a regular microstructure pattern. It has good process compatibility, low manufacturing cost, and is suitable for the large-scale manufacturing of image sensors. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the manufacturing process of an image sensor according to the present invention.

[0019] Figure 2 This is a simplified structural diagram of the pixel area and non-imaging area on the substrate of the present invention. Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the image sensor and its manufacturing process proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0021] Currently, to reduce light spots and ghosting in image sensors, the industry commonly places a light-shielding layer on the surface of non-imaging areas. Its core function is to block non-imaging light from directly penetrating the logic area, preventing interference with the photosensitive process in the pixel area. If non-imaging light directly passes through the metal wiring and dielectric layer of the logic area, it may reach the photodiodes in the pixel area, causing signal crosstalk and directly affecting image clarity. Black light-absorbing materials have become the mainstream choice for light-shielding layers due to the following advantages: (1) High light absorption efficiency: Depending on the application of the image sensor, black light-absorbing materials can be used to absorb visible light (400nm~760nm) and / or near-infrared light (760nm~1100nm, some sensors need to be covered). Their absorption coefficient is usually >90%, which can absorb most of the incident light and convert it into heat energy, rather than passing through or reflecting it, thus reducing the propagation of non-imaging light from the source. The rough surface can also cause the incident light to be scattered in multiple directions and further absorbed by the black light-absorbing material, thereby reducing the backlight.

[0022] (2) Low transmittance: The transmittance of high-quality black light-absorbing materials (such as special black photoresist) is <1%, which is much lower than that of ordinary metals (such as aluminum and copper, with a transmittance of about 5%~10%) or transparent media, and can completely block "transmitting stray light". It should be noted that the transmittance and reflectance of the black light-absorbing material layer will vary with the film thickness.

[0023] (3) Good compatibility with the underlying structure: The chemical properties of the black light-absorbing material are stable. It will not react chemically with the metal wiring (copper, tungsten) or dielectric layer (silicon oxide, silicon nitride) in the logic area of ​​the non-imaging area, nor will it corrode the silicon substrate. It can be directly deposited or coated on the existing structure without the need for an additional transition layer.

[0024] (4) Low material cost: The raw material price of light-absorbing materials such as black photoresist and black polymer is only 1 / 10-1 / 5 of that of inorganic light-blocking materials (such as rare metal oxides and multilayer stacked structures), and the cost is lower.

[0025] It is evident that the "high light absorption and low light transmittance" characteristics of black light-absorbing materials meet the light-shielding requirements, while their strong process compatibility and controllable cost make them suitable for the needs of large-scale production in the industry. However, significant drawbacks still exist in practical applications: due to limitations in material preparation processes, the surface of black light-absorbing materials typically exhibits a smooth, mirror-like appearance. When non-imaging light shines on this smooth surface, strong specular reflection occurs, forming stray light. After multiple reflections within the image sensor, this stray light may eventually penetrate the light-shielding structure of the pixel area and be captured by the photodiode, thus forming optical artifacts such as light spots or ghosting in the image. These optical artifacts lead to decreased image contrast, blurred details, and severely degraded image quality.

[0026] To address these issues, the industry has developed technical solutions using inorganic light-shielding layers. These solutions leverage the properties of inorganic materials to reduce reflectivity. However, the following problems still exist: Firstly, some inorganic light-shielding materials cannot be directly grown on the silicon substrate or the metal wiring layer of the logic region, requiring an additional transition layer preparation step. Secondly, the process is complex, requiring special deposition and etching processes, which significantly increases manufacturing costs.

[0027] It is evident that existing light-shielding layers cannot simultaneously meet the core requirements of "efficiently reducing surface reflection in non-imaging areas" and "process compatibility and cost control".

[0028] To address the aforementioned technical problems, this invention provides a manufacturing process for an image sensor. This process involves forming an anti-reflective layer over at least a portion of a non-imaging area of ​​a substrate, covering the top of the non-imaging area with the anti-reflective layer. The anti-reflective layer is then etched to randomly roughen its surface. The anti-reflective layer is composed of at least a first black light-absorbing material and a second black light-absorbing material with different etching rates. This invention etches black light-absorbing materials with different etching rates to form an anti-reflective layer with a roughened surface in the non-imaging area. This process treats incident light, converting specular reflection into diffuse reflection, significantly reducing the intensity of reflected light in all directions. This fundamentally reduces stray light entering the pixel area, avoids light spots and ghosting, and improves image quality.

[0029] like Figure 1 As shown, the present invention provides a manufacturing process for an image sensor, comprising at least: Step S1: Provide a substrate on which a pixel area and a peripheral non-imaging area are formed.

[0030] The pixel area is the "photosensitive core" of the image sensor, composed of an array of millions or even hundreds of millions of tiny photodiodes (PDs). Each photodiode is responsible for capturing incident photons and converting them into electrical signals. The non-imaging area contains a logic area, which contains complex peripheral circuitry responsible for controlling the operation of the pixel area. This logic area performs functions such as signal readout, signal amplification, exposure control, signal processing, and transmission, and is crucial for ensuring the orderly output of image data.

[0031] Step S2: An anti-reflective layer is formed above the non-imaging area, the anti-reflective layer covering at least a portion of the top of the non-imaging area.

[0032] To form a light-shielding layer above the non-imaging area, an anti-reflective layer is formed above the non-imaging area using screen printing or photolithography. The anti-reflective layer at least partially covers the top of the non-imaging area. Its core purpose is to block non-imaging light from entering from any area of ​​the non-imaging area, thus preventing stray light from interfering with pixel imaging. If the light-shielding layer does not completely cover the logic area, non-imaging light will directly illuminate the surface of the metal / dielectric layer of the non-imaging area. Due to the high reflectivity of these structures, strong stray light will be generated.

[0033] Step S3: Etch the anti-reflective layer to randomly roughen the surface of the anti-reflective layer.

[0034] In order to perform random surface roughening treatment on the anti-reflective layer, the material of the anti-reflective layer includes at least a first black light-absorbing material and a second black light-absorbing material with different etching rates, and a nanoscale random rough texture is formed on the surface of the anti-reflective layer by etching selection ratio.

[0035] In this invention, the first black light-absorbing material can be a black organic light-absorbing material containing a binder resin, and the second black light-absorbing material can be black particles or black fillers dispersed in the first black light-absorbing material. Specifically, the first black light-absorbing material may include a binder resin and black dyes, black pigments, or other light-absorbing components dispersed or dissolved in the binder resin, so that the first black light-absorbing material is entirely black and has light-absorbing properties. The binder resin may include acrylic resins, epoxy resins, polyimides, phenolic resins, or combinations thereof, to provide film-forming properties, adhesion, and patterning processing properties.

[0036] The second black light-absorbing material may include black particles, black pigment particles, carbon black particles, titanium black particles, organic black pigment particles, inorganic black pigment particles, or combinations thereof, for absorbing incident light and / or scattered light. The second black light-absorbing material may be regular particles or an amorphous filler; when the second black light-absorbing material is a filler material, its morphology may be at least one of amorphous, flake-like, block-like, aggregated, or porous. The second black light-absorbing material is randomly dispersed within the first black light-absorbing material, thereby forming a randomly distributed dispersed phase structure within the antireflective layer.

[0037] The first black light-absorbing material and the second black light-absorbing material have different etching rates. Preferably, when etching the anti-reflective layer, the etching rate of the second black light-absorbing material is less than that of the first black light-absorbing material, so that the first black light-absorbing material is preferentially etched away relative to the second black light-absorbing material, while the second black light-absorbing material is relatively retained or removed at a slower rate. Thus, on the surface of the anti-reflective layer, the areas where the second black light-absorbing material is located form relatively protrusions, shielding points, or microstructural support points, while the areas of the first black light-absorbing material between adjacent second black light-absorbing materials form relatively depressions, thereby forming a randomly rough surface determined by the random distribution of the second black light-absorbing material.

[0038] In other words, the roughening of the anti-reflective layer does not rely on a regular photolithography pattern, but rather utilizes the random dispersion state of the second black light-absorbing material within the first black light-absorbing material, and the etching selectivity ratio between the first and second black light-absorbing materials, to form a random uneven structure during the etching process. Because the distribution position, particle size, morphology, and / or aggregation state of the second black light-absorbing material are random, the rough surface formed after etching also exhibits corresponding random distribution characteristics.

[0039] In some embodiments, the average particle size of the second black light-absorbing material is 40 nm to 100 nm. In other embodiments, the height difference, peak-valley difference, and / or surface roughness of the random rough structure formed after etching the antireflective layer is 100 nm to 300 nm. The random rough structure can be a moth-eye-like structure, a random protrusion structure, a random depression structure, or a random peak-valley structure.

[0040] Specifically, the antireflective layer can be etched using a dry etching process. The dry etching process may include plasma etching, reactive ion etching, or ashing etching. During the etching process, at least one of an oxygen-containing gas, a fluorine-containing gas, and an inert gas can be introduced into the reaction chamber, and the plasma source can be turned on, so that the first black light-absorbing material and the second black light-absorbing material are etched at different etching rates, thereby forming a random rough structure on the surface of the antireflective layer. In some embodiments, the oxygen-containing gas includes oxygen, the fluorine-containing gas includes at least one of carbon tetrafluoride, sulfur hexafluoride, and trifluoromethane, and the inert gas includes at least one of argon and helium.

[0041] When the surface of the anti-reflection layer is roughened, its microstructure consists of randomly distributed protrusions, depressions, peak-valley structures, or small facets. When light is incident on the roughened surface of the anti-reflection layer, it undergoes multi-directional scattering at the different orientations of the microstructures, dispersing the specularly reflected light that originally propagated in a specific direction into diffusely reflected light in multiple directions. Simultaneously, since the anti-reflection layer contains a first black light-absorbing material and a second black light-absorbing material, the scattered light can be further absorbed within the anti-reflection layer. This reduces the intensity of reflected light from non-imaging areas, decreasing the probability of reflected light entering the pixel area, thereby suppressing optical noise such as glare, ghosting, and ghosting, and improving the imaging quality of the image sensor. This invention, by converting the specular reflection of a smooth surface into diffuse reflection of a rough surface, can reduce surface reflectivity from 4% to 2% or even lower.

[0042] In this invention, the first black light-absorbing material may be a black organic light-absorbing material containing a binder resin, and the second black light-absorbing material may be black particles or black fillers dispersed in the first black light-absorbing material. The first black light-absorbing material may include a binder resin and black dyes, black pigments, or other light-absorbing components dispersed or dissolved in the binder resin, so that the first black light-absorbing material is entirely black and has light-absorbing properties. The binder resin may include acrylic resins, epoxy resins, polyimides, phenolic resins, or combinations thereof.

[0043] The second black light-absorbing material may include black pigment particles, carbon black particles, titanium black particles, organic black pigment particles, inorganic black pigment particles, or combinations thereof. The second black light-absorbing material may be regular particles or an amorphous filler; when the second black light-absorbing material is a filler material, its morphology may be at least one of amorphous, flake-like, blocky, agglomerated, or porous. In some embodiments, the average particle size of the second black light-absorbing material is 40 nm to 100 nm.

[0044] The first black light-absorbing material and the second black light-absorbing material have different etching rates. Preferably, the etching rate of the second black light-absorbing material is lower than that of the first black light-absorbing material. Therefore, during the etching process, the first black light-absorbing material is preferentially etched away relative to the second black light-absorbing material, while the second black light-absorbing material is relatively retained or removed at a slower rate, thereby forming a random rough structure on the surface of the anti-reflective layer determined by the random distribution of the second black light-absorbing material. An adhesive resin, transparent filler, or other filler may also be filled between the first and second black light-absorbing materials to adjust the film-forming properties, adhesion, transmittance, refractive index, and / or etching selectivity of the anti-reflective layer.

[0045] In some embodiments, to further optimize the light-shielding and anti-reflection effects for specific wavelengths, at least one of a red filter layer, a blue filter layer, a first black light-absorbing material layer, and a second black light-absorbing material layer is disposed between the logic area and the anti-reflection layer. The red filter layer and the blue filter layer can form a stacked light-shielding structure to absorb or block light of specific wavelengths; the first black light-absorbing material layer and / or the second black light-absorbing material layer can further absorb incident light, scattered light, or reflected light, thereby reducing the intensity of reflected light in non-imaging areas together with the surface-roughened anti-reflection layer.

[0046] Although black light-absorbing materials have high absorption capacity for visible and / or near-infrared light, insufficient absorption or residual reflection may still occur in certain wavelength bands. By placing at least one of a red filter layer, a blue filter layer, a first black light-absorbing material layer, and a second black light-absorbing material layer between the logic area and the anti-reflection layer, light that is not fully absorbed by the anti-reflection layer can be further absorbed or blocked, thereby reducing the probability of incident light, scattered light, or reflected light entering the logic area or being reflected back to the pixel area, and further suppressing optical noise such as glare, ghosting, and double images.

[0047] After the surface roughening treatment of the anti-reflective layer is completed, this invention also includes other conventional manufacturing steps for image sensors, such as forming color filter arrays and microlens arrays on the pixel area, ultimately completing the fabrication of the image sensor. The anti-reflective layer can also serve as a barrier layer or stop layer in subsequent processes to facilitate the formation of subsequent film layers.

[0048] like Figure 2 As shown, in this invention, the pixel region can be an effective imaging area in an image sensor used to receive incident light and perform photoelectric conversion, for example... Figure 2 The non-imaging area is located around the pixel area and is not used as an effective imaging area. The non-imaging area may include a first non-imaging area and a second non-imaging area surrounding the pixel area. The first non-imaging area may include an I / O electrode area, a pad area, or a peripheral metal electrode area, and the second non-imaging area may include at least one of a logic circuit area, an optical black area, a virtual pixel area, and a pixel extension area. The anti-reflective layer may cover the first non-imaging area and / or the second non-imaging area to reduce the reflection of incident light from the surface of the non-imaging area.

[0049] Color filter arrays are typically located above the pixel area to allow light of specific colors to pass through. Their formation process mainly includes the following steps: (1) Forming a grid structure: On the planarization layer above the pixel area, a grid made of opaque material is formed through deposition, photolithography and etching processes. The openings of the grid structure correspond one-to-one with the photodiodes (pixel units) below.

[0050] (2) Sequentially deposit and pattern each color filter layer: spin-coat a layer of green filter material on the entire wafer surface, remove the green material in the unwanted areas by exposure and development, leaving only the green filter in the predetermined position, and bake and cure the left green filter; then spin-coat a red filter material, and expose, develop and cure the corresponding red pixel position with a photomask to form a red filter; finally, similarly spin-coat a blue filter material, and expose, develop and cure the corresponding blue pixel position with a photomask to form a blue filter.

[0051] After forming filters of all colors, a chemical mechanical polishing process is performed to flatten the surface of the color filter array, providing a flat substrate for the subsequent fabrication of microlens arrays.

[0052] The microlens array, located above the color filter array, is used to converge incident light and improve the light-gathering efficiency of each pixel. Its formation process mainly includes the following steps: (1) Deposit of lens material layer: A layer of microlens material is spin-coated on the planarized surface of the color filter array to form a lens material layer, which is usually a transparent organic polymer.

[0053] (2) Patterning and thermal reflow: The microlens pattern is defined on the lens material layer by photolithography. Specifically, photoresist is applied, and the microlens array pattern is exposed and developed using a photomask. Cylindrical or prismatic lens precursor patterns are formed on the lens material layer. The positions of these patterns are aligned with the color filters below. The wafer is heated at a certain temperature. During the heating process, the material of the lens precursor pattern melts and flows. Due to the surface tension, a smooth convex surface is naturally formed on its top, thereby forming a hemispherical or near-hemispherical microlens. The formed microlens is solidified to fix its shape and have the required mechanical and optical stability.

[0054] In summary, the present invention provides a manufacturing process for an image sensor, comprising: providing a substrate on which pixel areas and a peripheral non-imaging area are formed; forming an anti-reflection layer over at least a portion of the non-imaging area, the anti-reflection layer covering the top of the non-imaging area; etching the anti-reflection layer to roughen its surface; wherein the material of the anti-reflection layer comprises at least a first black light-absorbing material and a second black light-absorbing material, the first black light-absorbing material and the second black light-absorbing material having different etching rates. By etching the first black light-absorbing material and the second black light-absorbing material with different etching rates, the etching selectivity between the two materials is used to form a random rough structure on the surface of the anti-reflection layer, thereby disrupting the specular reflection conditions of the smooth surface, causing incident light to be scattered in multiple directions on the surface of the anti-reflection layer, and further absorbed by the first black light-absorbing material and the second black light-absorbing material during the scattering process. This reduces the intensity of reflected light propagating towards the pixel area, reduces stray light entering the pixel area, thereby suppressing optical noise such as glare, ghosting, and double images, and improving the imaging quality of the image sensor.

[0055] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0057] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0059] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A manufacturing process for an image sensor, characterized in that, At least includes: A substrate is provided on which pixel areas and peripheral non-imaging areas are formed; An anti-reflective layer is formed above the non-imaging area, the anti-reflective layer covering at least a portion of the top of the non-imaging area; The anti-reflective layer is etched to randomly roughen its surface. The anti-reflective layer comprises at least a first black light-absorbing material and a second black light-absorbing material, wherein the etching rates of the first black light-absorbing material and the second black light-absorbing material are different.

2. The manufacturing process as described in claim 1, characterized in that, The first black light-absorbing material contains carbon black, and the second black light-absorbing material contains organic black filler.

3. The manufacturing process as described in claim 1, characterized in that, The particle size of the first black light-absorbing material and the second black light-absorbing material is 40nm~100nm.

4. The manufacturing process as described in claim 1, characterized in that, The surface roughness of the anti-reflective layer is 100nm~300nm.

5. The manufacturing process as described in claim 1, characterized in that, The material of the antireflective layer also includes an adhesive resin, which includes acrylic resin or epoxy resin.

6. The manufacturing process as described in claim 1, characterized in that, At least one of the following is provided between the non-imaging area and the anti-reflection layer: a red filter, a blue filter, a first black light-absorbing material layer, and a second black light-absorbing material layer.

7. The manufacturing process as described in claim 1, characterized in that, The etching is a dry etching process.

8. The manufacturing process as described in claim 7, characterized in that, At least a silicon-containing gas and a fluorine-containing gas are introduced into the surface of the anti-reflection layer, and a plasma source is turned on. Under the action of the plasma, the silicon-containing gas dissociates into silicon-containing free radicals, and the fluorine-containing gas dissociates into fluorine-containing free radicals. The silicon-containing free radicals react with the fluorine-containing free radicals to etch the anti-reflection layer.

9. The manufacturing process as described in claim 8, characterized in that, It also includes introducing an inert gas into the surface of the antireflective layer.

10. An image sensor, characterized in that, The image sensor is prepared by the manufacturing process described in any one of claims 1 to 9.

Images