CN118073374A - Method for forming absorption enhancement structure of image sensor - Google Patents
Method for forming absorption enhancement structure of image sensor Download PDFInfo
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- CN118073374A CN118073374A CN202211473612.3A CN202211473612A CN118073374A CN 118073374 A CN118073374 A CN 118073374A CN 202211473612 A CN202211473612 A CN 202211473612A CN 118073374 A CN118073374 A CN 118073374A
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- 238000000034 method Methods 0.000 title claims abstract description 126
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 8
- 229910052710 silicon Inorganic materials 0.000 claims description 8
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- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 8
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 8
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
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- H—ELECTRICITY
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14601—Structural or functional details thereof
- H01L27/14625—Optical elements or arrangements associated with the device
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
- H01L27/14685—Process for coatings or optical elements
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Abstract
The invention provides a method for forming an absorption enhancement structure of an image sensor, which comprises the steps of forming a mask layer with an absorption enhancement structure shape above the surface of a substrate by improving the forming process of the mask layer, such as a back etching process, a reflow soldering process and a gradual light quantity photoetching process, etching the substrate by using the mask layer with the absorption enhancement structure shape to form the absorption enhancement structure which is rugged along the surface of the substrate, reducing the process difficulty of forming the absorption enhancement structure on the surface of the substrate, being beneficial to obtaining the absorption enhancement structure with a more ideal shape, realizing a better absorption enhancement effect, improving the quantum efficiency of the image sensor, and particularly improving the near infrared quantum efficiency.
Description
Technical Field
The present invention relates to the field of image sensors, and in particular, to a method for forming an absorption enhancement structure of an image sensor.
Background
An image sensor is a device for converting an optical image into an electronic signal, and is widely used in various fields such as digital cameras, camera phones, digital video cameras, medical imaging devices (e.g., gastroscopes), and vehicle imaging devices.
In the image sensor, an absorption enhancement structure with concave-convex fluctuation is often arranged on the surface of the substrate, the absorption enhancement structure can reduce the reflectivity of the substrate and increase the effective absorption of the substrate to light, so that the performances of the image sensor such as quantum efficiency and the like can be improved.
Fig. 1-3 illustrate a conventional method of making an absorption enhancement structure for a current image sensor: an absorption enhancing structure 103 of relief is formed on the surface of the substrate 100 by etching using a photoresist mask or a hard mask 102 patterned for the first time.
Limitations of conventional methods: because of the limitation of the prior art, the photoresist mask or the hard mask 102 formed in the first patterning process is generally in a shape similar to a cuboid (the longitudinal section is rectangular or a trapezoid similar to a rectangle, the included angle θ between the sidewall and the plane of the bottom is close to 90 °), so that the included angle between the sidewall of the recess 104 of the formed absorption enhancing structure 103 and the plane of the bottom (as shown by the dashed line in the figure) is also close to 90 °), but the shape similar to the expected absorption enhancing structure cannot be formed (the recess is similar to an inverted pyramid structure, and the included angle between the sidewall and the plane of the bottom is generally 30-60 °), so that the difficulty of forming the required absorption enhancing structure on the surface of the substrate is relatively high (especially when dry etching is adopted).
Disclosure of Invention
The invention aims to provide a method for forming an absorption enhancement structure of an image sensor, which reduces the process difficulty of forming the absorption enhancement structure on the surface of a substrate, is beneficial to obtaining the absorption enhancement structure with a more ideal shape, realizes a better absorption enhancement effect and improves the quantum efficiency of the image sensor.
In view of the foregoing, the present invention provides a method for forming an absorption enhancement structure of an image sensor, including: forming a mask layer having an absorption enhancing structure shape over a surface of a substrate; and etching the substrate by using the mask layer to form an absorption enhancement structure which is rugged along the surface of the substrate.
Preferably, the step of forming the mask layer having the shape of the absorption enhancing structure includes: forming a patterned first mask layer over the substrate surface; depositing a second mask layer above and between the first mask layers; the first mask layer and the second mask layer together form a third mask layer, and the third mask layer is made to form an absorption enhancement structure shape through an etching back process.
Preferably, the step of forming the mask layer having the shape of the absorption enhancing structure includes: forming a patterned fourth mask layer over the substrate surface; and forming the fourth mask layer into an absorption enhancement structure shape through a reflow soldering process.
Preferably, the step of forming the mask layer having the shape of the absorption enhancing structure includes: forming a fifth mask layer over the surface of the substrate; and forming the fifth mask layer into an absorption enhancement structure shape through a gradual light quantity photoetching process.
Preferably, the absorption enhancing structure comprises at least one recessed portion, the recessed portion being at least one of conical, pyramidal, frusto-conical, frusto-pyramidal.
Preferably, the acute angle between the side wall of the recessed portion and the plane of the bottom thereof is 30 ° -60 °.
Preferably, the method for forming the absorption enhancement structure of the image sensor further includes: at least one dielectric layer is deposited over the absorption enhancing structure.
Preferably, the dielectric layer comprises at least one of high-K dielectric materials having a dielectric constant K greater than 3.9.
Preferably, the first mask layer, the second mask layer, the fourth mask layer and the fifth mask layer are formed by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process and a spin coating process.
Preferably, the first mask layer and the second mask layer respectively comprise at least one of silicon oxide, silicon nitride and silicon oxynitride.
Preferably, the fourth mask layer and the fifth mask layer respectively include at least one of silicon oxide, silicon nitride, silicon oxynitride or photoresist.
Preferably, the substrate is etched by at least one of a dry etching process and a wet etching process.
According to the method for forming the absorption enhancement structure of the image sensor, the mask layer with the absorption enhancement structure shape is formed above the surface of the substrate through improving the forming process of the mask layer, such as a back etching process, a reflow soldering process and a gradual change light quantity photoetching process, and then the mask layer with the absorption enhancement structure shape is used for etching the substrate to form the absorption enhancement structure which is rugged along the surface of the substrate, so that the process difficulty of forming the absorption enhancement structure on the surface of the substrate is reduced, the absorption enhancement structure with a more ideal shape is facilitated to be obtained, a better absorption enhancement effect is achieved, the quantum efficiency of the image sensor is improved, and particularly the near infrared quantum efficiency is improved.
Drawings
Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments which follows, which is read in light of the accompanying drawings.
FIGS. 1-3 are process schematic diagrams of a method of forming an absorption enhancement structure of a prior art image sensor;
Fig. 4-8 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a first embodiment of the present invention;
Fig. 9-11 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a second embodiment of the present invention;
fig. 12-14 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a third embodiment of the present invention.
In the drawings, the same or similar reference numerals denote the same or similar devices (modules) or steps throughout the different drawings.
Detailed Description
In order to solve the above-mentioned problems in the prior art, the present invention provides a method for forming an absorption enhancement structure of an image sensor, which comprises the steps of forming a mask layer having an absorption enhancement structure shape over a surface of a substrate by improving a mask layer forming process, such as an etching back process, a reflow process, and a gradual light-passing lithography process, and etching the substrate by using the mask layer having the absorption enhancement structure shape to form an absorption enhancement structure having a concave-convex shape along the surface of the substrate, thereby reducing the difficulty of forming the absorption enhancement structure on the surface of the substrate, being beneficial to obtaining an absorption enhancement structure having a more ideal shape, realizing a better absorption enhancement effect, improving the quantum efficiency of the image sensor, and particularly improving the near infrared quantum efficiency.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof. The accompanying drawings illustrate, by way of example, specific embodiments in which the invention may be practiced. The illustrated embodiments are not intended to be exhaustive of all embodiments according to the invention. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
The invention provides a method for forming an absorption enhancement structure of an image sensor, which comprises the following steps: forming a mask layer having an absorption enhancing structure shape over a surface of a substrate; and etching the substrate by using the mask layer to form an absorption enhancement structure which is rugged along the surface of the substrate.
The process of the invention is described in detail below with reference to specific examples.
Example 1
Fig. 4 to 8 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a first embodiment of the present invention.
Referring to fig. 4, a semiconductor substrate 200 is provided, and preferably, a trench isolation structure 201 may be formed in the substrate 200 in advance for isolation between pixel cells.
A patterned first mask layer 205 is then formed over the surface of the substrate 200. The first mask layer 205 may be formed by using a conventional hard mask material, for example, at least one of silicon oxide, silicon nitride, silicon oxynitride, and other suitable materials, and depositing a hard mask layer 205 on the surface of the substrate 200 by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, a spin-on process, or other suitable deposition process, depositing a photoresist layer, not shown, over the hard mask layer 205, and patterning the photoresist layer by photolithography and etching processes, thereby forming the patterned first mask layer 205 as shown in fig. 4. The patterned first mask layer 205 is generally formed to be approximately rectangular parallelepiped in shape (the angle between the sidewall and the plane of the bottom is approximately 90 °) due to limitations of the prior art.
Referring to fig. 5, a second mask layer 206 is next deposited over and between the patterned first mask layers 205. The second mask layer 206 is made of a hard mask material, for example, at least one selected from silicon oxide, silicon nitride, and silicon oxynitride, and may be the same as or different from the first mask layer 205. The deposition process of the second mask layer 206 may be at least one selected from a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, and a spin-on process, and may be the same as or different from the deposition process of the first mask layer 205. The first mask layer 205 and the second mask layer 206 together form the third mask layer 202.
Referring to fig. 6 and 7, a maskless back etching (etch-back) process is performed on the third mask layer 202, so that the shape of the third mask layer 202 is changed to gradually form an absorption enhancing structure shape, and then the substrate 200 is etched by using the third mask layer 202 with the absorption enhancing structure shape to form the absorption enhancing structure 203 with concave-convex relief along the surface of the substrate 200.
The etching back process may only etch a partial region of the second mask layer 206, or may further etch a partial region of the first mask layer 205, specifically, the shape of the third mask layer 202 after etching back may be as close as possible to the shape of the expected absorption enhancing structure by controlling the etching back condition according to the product design requirement. Specifically, contemplated absorption enhancing structures 203 include at least one recessed portion 204, in this embodiment, the recessed portion 204 is conical or pyramidal, as will be appreciated by those skilled in the art, and the recessed portion 204 may also be provided in at least one of a truncated conical, truncated pyramidal, or other inverted pyramid-like shape as shown in FIG. 8, as desired. Further preferably, the acute angle α between the sidewall of the concave portion 204 and the plane (as shown by the dashed line in the figure) where the bottom of the concave portion is located is 30 ° -60 °, so that the absorption enhancing structure 203 has a better absorption enhancing effect, which can effectively reduce the reflectivity of the substrate 200 and increase the effective absorption of light by the substrate 200, thereby improving the quantum efficiency of the image sensor, in particular, improving the performance such as near infrared quantum efficiency.
After forming the third mask layer 202 having the shape of the absorption enhancing structure over the surface of the substrate 200 by the back etching process, the substrate 200 may be etched, preferably by at least one of a dry etching process and a wet etching process, to form the absorption enhancing structure 203 having the relief along the surface of the substrate 200. Because the third mask layer 202 has the shape of the absorption enhancement structure by improving the mask layer forming process, when the substrate 200 is etched by using the third mask layer 202 with the shape of the absorption enhancement structure, the process difficulty of forming the absorption enhancement structure on the surface of the substrate is reduced, the absorption enhancement structure with a more ideal shape is favorably obtained, the better absorption enhancement effect is realized, the quantum efficiency of the image sensor is improved, and particularly the near infrared quantum efficiency is improved.
In addition, in other embodiments not shown, after forming the absorption enhancing structure 203, at least one dielectric layer may be further deposited over the absorption enhancing structure 203, which may comprise at least one of high-K dielectric materials having a dielectric constant K greater than 3.9.
Example two
Fig. 9 to 11 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a second embodiment of the present invention.
Referring to fig. 9, a semiconductor substrate 300 is provided, and preferably, a trench isolation structure 301 may be formed in the substrate 300 in advance for isolation between pixel cells.
A patterned fourth mask layer 302 is then formed over the surface of the substrate 300. The fourth mask layer 302 may be a photoresist, and the photoresist layer 302 is formed on the surface of the substrate 300 by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, a spin coating process, or other suitable deposition process, and then patterned by a photolithography process; the fourth mask layer 302 may also be formed by using a conventional hard mask material, such as at least one of silicon oxide, silicon nitride, silicon oxynitride, and other suitable materials, and depositing a hard mask layer 302 on the surface of the substrate 300 by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, a spin-on process, or other suitable deposition process, depositing a photoresist layer not shown above the hard mask layer 302, and patterning the photoresist layer by photolithography and etching processes, thereby forming a patterned fourth mask layer 302 as shown in fig. 9. The patterned fourth mask layer 302 is generally formed to be approximately rectangular parallelepiped in shape (the angle between the sidewall and the plane of the bottom is approximately 90 °) due to limitations of the prior art.
Referring to fig. 10 and 11, a reflow (reflow) process is performed on the patterned fourth mask layer 302, so that the shape of the fourth mask layer 302 is changed to gradually form an absorption enhancing structure shape, and the substrate 300 is etched by using the fourth mask layer 302 having the absorption enhancing structure shape to form the absorption enhancing structure 303 with concave-convex relief along the surface of the substrate 300.
The reflow process may be performed by melting the material of the fourth mask layer 302 at a high temperature, causing the melted material at the top of the middle to flow toward the bottom of both sides, resulting in redistribution. Therefore, the shape of the fourth mask layer 302 after reflow can be made as close as possible to the shape of the intended absorption enhancement structure by controlling the reflow conditions according to the specific product design requirements. Specifically, contemplated absorption-enhancing structures 303 include at least one recessed portion 304, in this embodiment, the recessed portion 304 is conical or pyramidal, and in other embodiments not shown, the recessed portion 304 may also be provided in at least one of a frustoconical shape, a truncated pyramidal shape, or other inverted pyramid-like shape. Further preferably, the acute angle β between the sidewall of the concave portion 304 and the plane (as shown by the dashed line in the figure) where the bottom of the concave portion is located is 30 ° -60 °, so that the absorption enhancing structure 303 has a better absorption enhancing effect, which can effectively reduce the reflectivity of the substrate 300 and increase the effective absorption of light by the substrate 300, so as to improve the quantum efficiency of the image sensor, in particular, improve the performance such as near infrared quantum efficiency.
After forming the fourth mask layer 302 having the shape of the absorption enhancing structure over the surface of the substrate 300 by the reflow process, the substrate 300 may be etched, preferably by at least one of a dry etching process and a wet etching process, to form the absorption enhancing structure 303 having the relief along the surface of the substrate 200. Because the fourth mask layer 302 itself has the shape of the absorption enhancement structure by improving the mask layer forming process, when the substrate 300 is etched by using the fourth mask layer 302 having the shape of the absorption enhancement structure, the difficulty of forming the absorption enhancement structure on the surface of the substrate is reduced, which is favorable for obtaining the absorption enhancement structure with a more ideal shape, realizing a better absorption enhancement effect, improving the quantum efficiency of the image sensor, and particularly improving the near infrared quantum efficiency.
In addition, in other embodiments not shown, after forming the absorption enhancing structure 303, at least one dielectric layer may be further deposited over the absorption enhancing structure 303, which may comprise at least one of high-K dielectric materials having a dielectric constant K greater than 3.9.
Example III
Fig. 12-14 are process diagrams illustrating a method for forming an absorption enhancement structure of an image sensor according to a third embodiment of the present invention.
Referring to fig. 12, a semiconductor substrate 400 is provided, and preferably, a trench isolation structure 401 may be formed in the substrate 400 in advance for isolation between pixel units.
A fifth mask layer 402 is then deposited over the surface of the substrate 400 by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, a spin-on process, or other suitable deposition process. The fifth mask layer 402 may be a photoresist, or may be a hard mask material, such as at least one of silicon oxide, silicon nitride, silicon oxynitride, and other suitable materials.
Referring to fig. 13 and 14, next, the fifth mask layer 402 is patterned by a graded light quantity photolithography process, so that the fifth mask layer 402 forms an absorption enhancement structure shape, and the substrate 400 is etched by using the fifth mask layer 402 having the absorption enhancement structure shape to form an absorption enhancement structure 403 which is rugged along the surface of the substrate 400. Specifically, if the fifth mask layer 402 is photoresist, patterning it directly by a graded light quantity lithography process; if the fifth mask layer 402 is a hard mask layer, a photoresist layer, not shown, is deposited over the hard mask layer 402, then the photoresist layer is patterned by an graded light exposure lithography process, and then the pattern is transferred to the hard mask layer 402 by an etching process, thereby forming the fifth mask layer 402 into an absorption enhancement structure.
The gradual change light quantity photoetching process, also called as Gray-tone Lithography (Gray-tone Lithography) process, modulates the energy density distribution of processing light beams into different shapes through a Gray-tone mask plate, exposes photoresist, and forms micro devices once without moving the mask or moving a processing wafer or carrying out heat treatment on the photoresist, only needs to carry out certain coding and standard photoetching equipment on the mask plate, is easy to be compatible with other IC processes, and realizes the manufacture of a system chip structure. The gray scale photoetching technology uses a gray scale mask plate to modulate uniform radiation, micro-optical devices with any surfaces can be formed by one-time exposure and development, the surface smoothness of the devices can be ensured, the defects of alignment errors, multi-step photoetching and multi-layer masks in the binary photoetching process are eliminated, the performance and the quality of the devices are only related to exposure dose, are irrelevant to the processing process, and have strong repeatability.
Thus, fifth mask layer 402 may be directly shaped into the desired absorption enhancing structure during patterning by controlling the graded light throughput lithography conditions using a gray scale reticle (not shown) according to specific product design requirements. Specifically, contemplated absorption-enhancing structures 403 include at least one recessed portion 404, in this embodiment, the recessed portion 404 is conical or pyramidal, and in other embodiments not shown, the recessed portion 404 may also be provided in at least one of a frustoconical shape, a truncated pyramidal shape, or other inverted pyramid-like shape. Further preferably, the acute angle γ between the sidewall of the concave portion 404 and the plane (as shown by the dashed line in the figure) where the bottom of the concave portion is located is 30 ° -60 °, so that the absorption enhancing structure 403 has a better absorption enhancing effect, which can effectively reduce the reflectivity of the substrate 400 and increase the effective absorption of light by the substrate 400, so as to improve the quantum efficiency of the image sensor, especially improve the performance such as near infrared quantum efficiency.
After forming the fifth mask layer 402 having the shape of the absorption enhancing structure over the surface of the substrate 400 by the graded light quantity lithography process, the substrate 400 may be etched, preferably by at least one of a dry etching process and a wet etching process, to form the absorption enhancing structure 403 having the relief along the surface of the substrate 400. Because the fifth mask layer 402 has the shape of the absorption enhancing structure by improving the mask layer forming process, when the substrate 400 is etched by using the fifth mask layer 402 having the shape of the absorption enhancing structure, the process difficulty of forming the absorption enhancing structure on the surface of the substrate is reduced, the absorption enhancing structure with a more ideal shape is favorably obtained, the better absorption enhancing effect is realized, the quantum efficiency of the image sensor is improved, and particularly the near infrared quantum efficiency is improved.
In addition, in other embodiments not shown, after forming the absorption enhancing structure 403, at least one dielectric layer may be further deposited over the absorption enhancing structure 403, which may comprise at least one of high-K dielectric materials having a dielectric constant K greater than 3.9.
In summary, in the method for forming an absorption enhancement structure of an image sensor according to the present invention, by improving the forming process of the mask layer, for example, by an etching back process, a reflow process, and a gradual light-passing lithography process, the mask layer having the shape of the absorption enhancement structure is formed over the surface of the substrate, and then the mask layer having the shape of the absorption enhancement structure is used to etch the substrate to form the absorption enhancement structure with the concave-convex relief along the surface of the substrate, thereby reducing the difficulty of forming the absorption enhancement structure on the surface of the substrate, being beneficial to obtaining the absorption enhancement structure with a more ideal shape, realizing a better absorption enhancement effect, improving the quantum efficiency of the image sensor, and particularly improving the near infrared quantum efficiency.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Thus, the embodiments should be considered in all respects as illustrative and not restrictive. Furthermore, it is evident that the word "comprising" does not exclude other elements or steps, and that the word "a" or "an" does not exclude a plurality. The elements recited in the apparatus claims may also be embodied by one element. The terms first, second, etc. are used to denote a name, but not any particular order.
Claims (12)
1. A method of forming an absorption enhancement structure for an image sensor, comprising:
Forming a mask layer having an absorption enhancing structure shape over a surface of a substrate;
and etching the substrate by using the mask layer to form an absorption enhancement structure which is rugged along the surface of the substrate.
2. The method of forming an absorption enhancement structure for an image sensor according to claim 1, wherein the step of forming a mask layer having a shape of the absorption enhancement structure comprises:
Forming a patterned first mask layer over the substrate surface;
Depositing a second mask layer above and between the first mask layers;
the first mask layer and the second mask layer together form a third mask layer, and the third mask layer is made to form an absorption enhancement structure shape through an etching back process.
3. The method of forming an absorption enhancement structure for an image sensor according to claim 1, wherein the step of forming a mask layer having a shape of the absorption enhancement structure comprises:
forming a patterned fourth mask layer over the substrate surface;
And forming the fourth mask layer into an absorption enhancement structure shape through a reflow soldering process.
4. The method of forming an absorption enhancement structure for an image sensor according to claim 1, wherein the step of forming a mask layer having a shape of the absorption enhancement structure comprises:
forming a fifth mask layer over the surface of the substrate;
and forming the fifth mask layer into an absorption enhancement structure shape through a gradual light quantity photoetching process.
5. The method of forming an absorption enhancement structure for an image sensor according to claim 1, wherein the absorption enhancement structure comprises at least one recessed portion, the recessed portion being at least one of conical, pyramidal, frustoconical, and truncated pyramidal.
6. The method of forming an absorption enhancement structure for an image sensor according to claim 5, wherein an acute angle between a side wall of said recessed portion and a plane in which a bottom thereof is located is 30 ° to 60 °.
7. The method of forming an absorption enhancement structure for an image sensor of claim 1, further comprising: at least one dielectric layer is deposited over the absorption enhancing structure.
8. The method of claim 7, wherein the dielectric layer comprises at least one of a high K dielectric material having a dielectric constant K greater than 3.9.
9. The method of forming an absorption enhancement structure of an image sensor according to any one of claims 2 to 4, wherein the first mask layer, the second mask layer, the fourth mask layer, and the fifth mask layer are formed by at least one of a chemical vapor deposition process, a physical vapor deposition process, an atomic layer deposition process, and a spin coating process.
10. The method of claim 9, wherein the first mask layer and the second mask layer each comprise at least one of silicon oxide, silicon nitride, and silicon oxynitride.
11. The method of claim 9, wherein the fourth mask layer and the fifth mask layer each comprise at least one of silicon oxide, silicon nitride, silicon oxynitride, and photoresist.
12. The method of forming an absorption enhancement structure for an image sensor according to claim 1, wherein the substrate is etched by at least one of a dry etching process and a wet etching process.
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| CN (1) | CN118073374A (en) |
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2022
- 2022-11-23 CN CN202211473612.3A patent/CN118073374A/en active Pending
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