Image sensor

Abstract

The invention provides an image sensor, which is characterized in that a propagation path of non-imaging light is provided with at least one concave-convex surface, and the concave-convex surface diffusely reflects incident non-imaging light, so that on one hand, the intensity of the reflected non-imaging light reaching a pixel region is weakened, and on the other hand, the incident angle of the reflected non-imaging light is changed; therefore, the image effect is prevented from being influenced by imaging of the reflected non-imaging light. The concave-convex surface is arranged on the side wall of the medium structure, the concave-convex surface is defined when the photoetching process is used for patterning, and the manufacturing process is simple. And at least one concave-convex surface is arranged between two adjacent medium structures so as to reduce the stress between the two medium structures. Moreover, the number and the arrangement mode of the concave-convex surfaces are flexibly set according to the layout area, so that the performance of the image sensor is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of image sensors, and in particular to an image sensor. Background Art

[0002] Image sensors are divided into complementary metal oxide image sensors (CMOS Image Sensor, CIS) and charge coupled device (Charge Coupled Device, CCD) image sensors, which are usually used to convert optical signals into corresponding electrical signals.

[0003] Among them, CCD image sensors are difficult to integrate with other devices and consume a lot of power. In contrast, CIS has the advantages of simple process, easy integration, small size, light weight, low power consumption and low cost, and has been widely used in static digital cameras, camera phones, digital video cameras, medical cameras (such as gastroscopes), automotive cameras, etc.

[0004] CIS converts the light incident on the light receiving surface into an electrical signal in proportion. It uses multiple pixels to form a pixel array for radiation sensing to form an image. The periphery of the pixel array is provided with a trench isolation structure, a metal pad, a metal wire located in the peripheral circuit area and other functional devices.

[0005] In the prior art, in addition to the imaging light being incident on the pixel area for imaging, due to the influence of factors such as large-angle incidence or lens, the illumination range of the non-imaging light will exceed the field of view of the pixel area and will be incident outside the pixel area. It may also be reflected by the interface outside the field of view or multiple reflections from interface to interface, causing part of the non-imaging light to be reflected and enter the pixel area for imaging, generating an artifact known as flare, thereby causing image distortion and affecting the image effect. Summary of the invention

[0006] Based on the above considerations, the present invention provides an image sensor, which is provided with at least one concave-convex surface in the propagation path of non-imaging light to prevent the non-imaging light from forming an image and affecting the image effect.

[0007] Preferably, the concave-convex surface is arranged between different dielectric materials.

[0008] Preferably, the concave-convex surface is provided on at least one side of the pixel region and has a plurality of convex portions.

[0009] Preferably, the cross-section of the convex portion is polygonal or arc-shaped, or a combination of the two.

[0010] Preferably, the convex portions are arranged regularly or irregularly.

[0011] Preferably, the convex portions are arranged at equal or unequal distances from each other; and / or the convex portions are arranged at equal or unequal heights; and / or the convex portions are arranged at equal or unequal widths.

[0012] Preferably, the pixel area is arranged in the substrate, and further comprises: at least one dielectric structure having at least one concave-convex surface and at least partially arranged on the substrate and / or in the substrate and / or under the substrate.

[0013] Preferably, at least a portion of the surface of the medium structure is the concave-convex surface.

[0014] Preferably, at least one dielectric layer covers the concave-convex surface.

[0015] Preferably, the medium structure is a solid or hollow structure; and / or, the medium structure is a protrusion or a first groove.

[0016] Preferably, another or more medium structures having at least one concave-convex surface are disposed in the first groove.

[0017] Preferably, at least one concave-convex surface is provided between two adjacent medium structures.

[0018] Preferably, the two medium structures are provided with two symmetrically or asymmetrically arranged concave and convex surfaces to face or intersect.

[0019] Preferably, the convex parts between the two concave and convex surfaces are arranged opposite to each other or staggered.

[0020] Preferably, the two medium structures are provided with a concave-convex surface and a plane or a curved surface which are arranged opposite to or intersecting with each other.

[0021] Preferably, the material of the dielectric structure includes one of a light-blocking material and a light-absorbing material.

[0022] Preferably, the material of the dielectric structure is conductive or insulating.

[0023] Preferably, the material of the dielectric structure has a single crystal structure or a polycrystalline structure.

[0024] The present invention provides at least one concave-convex surface in the propagation path of the non-imaging light, and the concave-convex surface diffusely reflects the incident non-imaging light, on the one hand weakening the intensity of the reflected non-imaging light reaching the pixel area, and on the other hand changing the incident angle of the reflected non-imaging light, thereby avoiding the reflected non-imaging light from imaging and affecting the image effect.

[0025] Furthermore, the concave-convex surface is arranged on the side wall of the dielectric structure, and the concave-convex surface is defined during patterning in a photolithography process, which has the characteristic of simple manufacturing process.

[0026] Furthermore, at least one of the concave-convex surfaces is disposed between two adjacent dielectric structures to reduce stress between the two. Moreover, the number and arrangement of the concave-convex surfaces are flexibly set according to the layout area to improve the performance of the image sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0028] Figure 1 A schematic diagram showing a planar structure of an image sensor according to an embodiment of the present invention; Figure 2 A plan view showing a comparison of optical paths of a medium structure in the prior art and an embodiment of the present invention; Figure 3 Shown along Figure 2 A schematic diagram of a comparison cross section of the optical path of the I-I' section line; Figure 4 Shown along Figure 2 Schematic diagram of the second comparison section of the optical path along the I-I' section line; Figure 5 A schematic diagram showing a planar structure of a medium structure according to a first embodiment of the present invention; Figure 6 A schematic diagram showing a planar structure of a medium structure according to a second embodiment of the present invention; Figure 7 A schematic diagram showing a planar structure of a dielectric structure according to a third embodiment of the present invention; Figure 8 A schematic diagram showing a planar structure of a medium structure according to a fourth embodiment of the present invention; Fig. 9 A schematic diagram showing a planar structure of a medium structure according to a fifth embodiment of the present invention; Fig.10 A schematic diagram showing a planar structure of a dielectric structure according to a sixth embodiment of the present invention; Fig.11 A schematic diagram showing a planar structure of a medium structure according to a seventh embodiment of the present invention; Fig.12 A cross-sectional schematic diagram showing a comparison of optical paths of a groove structure in the prior art and an embodiment of the present invention; Fig.13 A second cross-sectional schematic diagram showing a comparison of optical paths of a groove structure in the prior art and an embodiment of the present invention; Fig.14 A schematic diagram showing a planar structure of an image sensor according to an embodiment of the present invention; Fig.15 Shown along Fig.14 Schematic diagram of the cross-sectional structure along the A-A' section line; Fig.16A schematic diagram showing a planar structure of an image sensor according to another embodiment of the present invention; Fig.17 Shown along Fig.16 Schematic diagram of the cross-sectional structure along the B-B' section line; Fig.18 A schematic diagram showing a planar structure of an image sensor according to another embodiment of the present invention; Fig.19 Shown along Fig.18 Schematic diagram of the cross-sectional structure along the C-C' section line; Fig. 20 A schematic diagram showing a planar structure of an image sensor according to yet another embodiment of the present invention; Fig.21 Shown along Fig. 20 Schematic diagram of the cross-sectional structure along the D-D' section line.

[0029] In the drawings, the same or similar reference numerals denote the same or similar devices (modules) or steps throughout different drawings. Implementation

[0030] To make the content of the present invention more clear and understandable, the content of the present invention is further described below in conjunction with the accompanying drawings of the specification. Of course, the present invention is not limited to this specific embodiment, and general replacements known to those skilled in the art are also covered within the protection scope of the present invention.

[0031] It should be noted that in the following specific embodiments, when describing the embodiments of the present invention in detail, in order to clearly represent the structure of the present invention for the convenience of explanation, the structures in the accompanying drawings are not drawn according to general proportions, and are partially enlarged, deformed and simplified. Therefore, it should be avoided to understand this as a limitation of the present invention.

[0032] The present invention provides at least one concave-convex surface in the propagation path of the non-imaging light, and the concave-convex surface diffusely reflects the incident non-imaging light, on the one hand weakening the intensity of the reflected non-imaging light reaching the pixel area, and on the other hand changing the incident angle of the reflected non-imaging light, thereby avoiding the reflected non-imaging light from imaging and affecting the image effect.

[0033] like Figure 1 As shown, Figure 1 The schematic diagram of the planar structure of an image sensor according to an embodiment of the present invention is shown. A pixel region 102 and a peripheral circuit region (not shown) are provided in a substrate 100 of the image sensor. The pixel region 102 is provided with a photodiode array (not shown), and each of the photodiodes is used to sense light incident from a photosensitive surface of the substrate 100.

[0034] The substrate 100 may be a silicon substrate, or may be a material appropriately used in image sensors such as germanium, silicon germanium, silicon carbide, gallium arsenide, or indium gallium, or may be a silicon substrate on an insulator surface or a germanium substrate on an insulator surface.

[0035] like Figure 1 As shown, under actual design / process, a number of dielectric structures are provided around the pixel area 102, such as metal interconnection structure, contact hole structure, isolation structure and circuit pad, etc. For example, dielectric structure 1001 is located on the substrate 100, a groove 1002 and another groove 1004 are respectively provided in the substrate 100, dielectric structure 1005 is located in the groove 1004, dielectric structure 1006 is provided in the substrate 100, the non-photosensitive surface of the substrate 100 is covered with dielectric layer 101, and dielectric structure 1007 is provided in the dielectric layer 101. The positions and sizes of the above-mentioned dielectric structures can be flexibly set according to the design of the image sensor, and should not be limited as the content of the present invention.

[0036] Please combine Figure 3 and Figure 4 And refer to Figure 2 , Figure 2 A plan view showing a comparison of optical paths of a medium structure in the prior art and an embodiment of the present invention; Figure 3 Shown along Figure 2 A schematic diagram of a comparative cross section of the optical path of the I-I' section line; Figure 4 Shown along Figure 2 Schematic diagram of the second comparison section of the optical path along the I-I' section line.

[0037] The light emitted by the light source 120 passes through the protective cover 110 above the substrate 100 to enter the pixel area 102. The imaging light is located within the field of view of the pixel area 102, that is, within a specific angle above the pixel area 102; the light outside the field of view of the pixel area 102 is non-imaging light.

[0038] The imaging light is sensed by the photodiode array to output an image signal. Ideally, the non-imaging light is reflected by the surface of the substrate 100 and / or the surface of the protective cover and moves away from the pixel area 102 .

[0039] Preferably, the concave-convex surface is arranged on the side wall of the dielectric structure, and the concave-convex surface is defined by a photolithography process, which has the characteristic of simple manufacturing process.

[0040] like Figure 2 As shown, each dielectric structure in the prior art, such as a dielectric structure 1001 located on the substrate 100, mostly has flat surfaces, such as planar side walls, flat top surfaces and bottom surfaces.

[0041] like Figure 3 As shown, non-imaging light is incident on the side wall of the dielectric structure 1001 and is reflected to the pixel area 102. The plane side wall of the prior art reflects the non-imaging light or the non-imaging light that has been reflected at least once, so that the non-imaging light that changes direction after one or more reflections and is reflected enters the pixel area 102 for imaging, resulting in the formation of artifacts and affecting the image effect.

[0042] The present invention sets at least part of the surface of another dielectric structure 1001' as a concave-convex surface, such as Figure 3 As shown, the non-imaging light is incident on the side wall of the dielectric structure 1001 ′ and changes the reflection angle due to diffuse reflection, for example, it is reflected to the protective cover 110 and then reflected to the pixel area.

[0043] At least a portion of the surface of at least a portion of the medium structure located outside the pixel area 102 is set to a concave-convex surface, and the concave-convex surface diffusely reflects the incident non-imaging light, which on the one hand weakens the intensity of the reflected non-imaging light reaching the pixel area, and on the other hand changes the incident angle of the reflected non-imaging light, thereby avoiding the reflected non-imaging light from imaging and affecting the image effect.

[0044] In one embodiment, if Figure 5 As shown, Figure 5 The planar structure schematic diagram of the medium structure of the first embodiment of the present invention is shown. The concave-convex surface may have a plurality of regularly arranged convex portions. The convex portions may be arranged with equal distances and / or equal heights and / or equal widths.

[0045] In one embodiment, if Figure 6 As shown, Figure 6 The schematic diagram of the planar structure of the medium structure of the second embodiment of the present invention shows that the concave-convex surface may have a plurality of irregularly arranged convex portions. The convex portions may be arranged at unequal distances and / or unequal heights and / or unequal widths.

[0046] In one embodiment, if Figure 7 As shown, Figure 7 A schematic diagram of the planar structure of the medium structure of the third embodiment of the present invention is shown, wherein the concave-convex surface may have a plurality of irregularly arranged convex portions, and a portion of the convex portions are arranged according to rule one, and another portion of the convex portions are arranged according to rule two, wherein rule one and rule two may be arranged with unequal distances and / or unequal heights and / or unequal widths.

[0047] In one embodiment, if Figure 8 As shown, Figure 8 A schematic diagram of the planar structure of the medium structure of the fourth embodiment of the present invention is shown, wherein the concave-convex surface may have a plurality of irregularly arranged convex portions, and some of the convex portions are arranged according to shape one, and some of the convex portions are arranged according to shape two, wherein shape one and shape two may be the same or different, and the cross-section of the convex portion may be one or a combination of two of a polygon and an arc.

[0048] In one embodiment, if Fig. 9 As shown, Fig. 9 A schematic diagram of the planar structure of the medium structure of the fifth embodiment of the present invention is shown. The concave-convex surface may have a plurality of regularly arranged convex portions, and each of the convex portions may protrude from the surface of the medium structure or may be flush with the surface of the medium structure.

[0049] In one embodiment, if Fig.10 , Fig.11 As shown, Fig.10 , Fig.11 The schematic diagram of the planar structure of the medium structure of the sixth embodiment of the present invention is shown. The concave-convex surface may have a plurality of regularly arranged convex portions, and a concave portion is provided between each of the convex portions. Each of the convex portions may protrude from the surface of the medium structure, or may be flush with the surface of the medium structure. The convex portion or the concave portion may be a curved surface structure, or may be a planar structure.

[0050] Fig.12 A cross-sectional diagram showing a comparison of optical paths of a groove structure in the prior art and an embodiment of the present invention; Fig.13 A second cross-sectional schematic diagram showing a comparison of optical paths of a groove structure in the prior art and an embodiment of the present invention; The groove structures in the prior art, such as a groove structure 1002 located on the substrate 100, mostly have flat surfaces, such as planar sidewalls, flat top surfaces and bottom surfaces.

[0051] like Fig.12 As shown, non-imaging light is incident on the sidewall of the groove structure 1002 and is reflected to the bottom thereof, and is reflected again from the bottom to another sidewall or the protective cover 110. The planar sidewall of the prior art reflects non-imaging light or non-imaging light that has been reflected at least once, so that the non-imaging light that changes direction after one or more reflections and is reflected enters the pixel area 102 for imaging, resulting in the formation of artifacts and affecting the image effect.

[0052] The present invention sets at least part of the surface of another groove structure 1002' as a concave-convex surface, such as Fig.12 As shown, the non-imaging light is incident on the sidewall of the groove structure 1002 ′ and changes the reflection angle due to diffuse reflection, for example, it is reflected to the protection cover 110 and then reflected to the pixel area.

[0053] like Fig.13 As shown, non-imaging light is incident on the bottom of the groove structure 1002 and is reflected to the sidewall thereof, and is reflected again to the protective cover 110 by the sidewall. In the present invention, at least part of the surface of the groove structure 1002' is configured as a concave-convex surface, and non-imaging light is incident on the bottom of the groove structure 1002' and is diffusely reflected to change the reflection angle, for example, after being reflected to the protective cover 110, it is reflected to the pixel area.

[0054] At least part of the surface of at least part of the groove structure outside the pixel area 102 is set to a concave-convex surface, which diffusely reflects the incident non-imaging light, on the one hand weakening the intensity of the reflected non-imaging light reaching the pixel area, and on the other hand changing the incident angle of the reflected non-imaging light, thereby avoiding the reflected non-imaging light from imaging and affecting the image effect.

[0055] Fig.14 A schematic diagram showing a planar structure of an image sensor according to an embodiment of the present invention; Fig.15 Shown along Fig.14 Schematic diagram of the cross-sectional structure along the A-A' section line.

[0056] like Fig.14 As shown, the dielectric structure may be a trench isolation structure 103 disposed between the pixel region 102 and the peripheral circuit region, and extending from one surface (photosensitive surface) of the substrate 100 to the other surface.

[0057] The trench isolation structure 103 is provided on at least one side of the pixel region 102 and may be filled with heat-insulating material and / or insulating material and / or light-absorbing material and / or light-blocking material, etc., to isolate light and / or heat and / or photogenerated carriers from the peripheral circuit region. The dielectric structure may also be a through-silicon via (not shown) or a silicon trench (not shown) that passes through the substrate 100.

[0058] In this embodiment, the trench isolation structure 103 surrounds the pixel area 102, and the side wall thereof facing the pixel area 102 is a concave-convex surface. Part of the non-imaging light passes through the substrate 100 and is incident on the concave-convex surface and diffusely reflected, thereby changing the reflection direction and at least partially moving away from the pixel area 102 and being weakened.

[0059] One or more dielectric structures are provided in the peripheral pixel region. When the dielectric structure is provided on the substrate 100, the other side of the trench isolation structure 103 facing away from the peripheral pixel region can also be provided as a concave-convex surface (not shown) to diffusely reflect non-imaging light diffusely reflected or specularly reflected by the dielectric structure.

[0060] Meanwhile, part or all of the sidewalls of the dielectric structure disposed adjacent to the trench isolation structure 103 may be configured as a concave-convex surface to reduce stress between the dielectric structure and the trench isolation structure 103 .

[0061] When the dielectric structure is partially or completely disposed inside the substrate 100, at least the side wall facing the pixel area 102 may be configured as a concave-convex surface to diffusely reflect a portion of non-imaging light passing through the substrate 100. However, it can be understood by those skilled in the art that the concave-convex surface may also be disposed on the remaining surfaces of the dielectric structure, such as the top surface, the bottom surface, and the remaining side walls.

[0062] like Fig.14 As shown, the tooth-shaped protrusions can be arranged side by side and extend inward from the surface of the substrate 100. Part of the reflected non-imaging light is reflected back and forth between adjacent protrusions to attenuate. The cross-section of the protrusion can be one of polygonal and arc-shaped or a combination of the two. For example, it can also be wavy to reduce the stress between adjacent dielectric structures.

[0063] It is understood that the figure only shows a partial area of ​​the pixel area 102. The peripheral circuit area is arranged at the periphery of the pixel area 102, and is provided with a number of peripheral components and circuits of the image sensor.

[0064] The material of the dielectric structure may be conductive or insulating.

[0065] In this embodiment, the first metal wire 104 is formed on the photosensitive surface of the substrate 100. Part of the non-imaging light reaches the first metal wire 104 after passing through the protective cover 110. The first metal wire reflects the part of the non-imaging light, so that the part of the reflected non-imaging light enters the imaging area. A plurality of convex portions arranged regularly or irregularly are provided on the exposed surface of the first metal wire 104 to diffusely reflect the part of the non-imaging light, which can reduce the specular reflection of the reflected non-imaging light to the pixel area 102, thereby avoiding the influence of the reflected non-imaging light on the pixel area 102.

[0066] like Fig.15 As shown, the top surface of the first metal wire 104 can be set as a concave-convex top surface. When part of the non-imaging light is reflected by the substrate 100 to the protective cover 110 and then reflected by the protective cover 110 to the concave-convex top surface again, the concave-convex top surface diffusely reflects the non-imaging light.

[0067] The first metal wire 104 is formed on the substrate 100 of the peripheral circuit. A plurality of first metal wires 104 may be formed on the substrate 100. Each of the first metal wires 104 may be connected to the pixel region 102, peripheral components and circuits respectively.

[0068] The first metal wire 104 may be isolated from the substrate 100 by a dielectric material (not shown). The first metal wire 104 is formed, for example, by depositing a metal layer on the substrate 100 and photolithographically etching the metal layer, and a plurality of convex portions are formed on both sides of the first metal wire 104 at equal or non-equal intervals to form a concave and convex sidewall (not shown). The material of the first metal wire 104 may include at least one of a single metal (such as copper, nickel, zinc, tin, silver, gold, tungsten, magnesium, tantalum, titanium, molybdenum, platinum, aluminum, hafnium, ruthenium, etc.) and an alloy (such as a copper alloy or an aluminum alloy, etc.).

[0069] The first metal wire 104 may include a multi-layer patterned conductive layer (not shown) isolated by an insulating material and a conductive plug (not shown) connecting adjacent conductive layers. The conductive layer and the conductive plug provide interconnection between various doped regions, circuits and input / outputs of the image sensor, and a concave-convex surface is set between different dielectric materials to reduce stress between each other.

[0070] Among the two dielectric structures, a portion of the sidewall of one of the dielectric structures is provided with a concave-convex surface, and the surface of the remaining sidewall is a curved surface or a flat surface to be opposite to or intersecting with another concave-convex surface of the sidewall of the other dielectric structure; or, a portion or all of the sidewall of one of the dielectric structures is provided with a concave-convex surface, and a portion or all of the sidewall of the other dielectric structure is provided with another concave-convex surface opposite to the concave-convex surface to reduce the stress between the two, and the non-imaging light is diffusely reflected back and forth in the two dielectric structures and attenuated.

[0071] like Fig.14 As shown, the second metal wire 105 is disposed on the other side of the pixel region 102, and the sidewalls thereof are both concave-convex surfaces.

[0072] Among them, a portion of the second metal wire 105 can be arranged on the substrate 100 on the other side of the pixel area 102. When part of the non-imaging light is incident on the side wall of the second metal wire 105, the concave-convex surface diffusely reflects the non-imaging light to weaken the non-imaging light and at least partially move it away from the pixel area 102.

[0073] Another portion of the second metal wire 105 may extend into the substrate 100 on the other side of the pixel region 102 and be disposed opposite to the trench isolation structure 103, that is, the concavo-convex surface of one side wall of the second metal wire 105 is disposed opposite to the concavo-convex surface of one side wall of the trench isolation structure 103, and the stress between the second metal wire 105 and the trench isolation structure 103 is reduced by the two concavo-convex surfaces being disposed opposite to each other. Moreover, when non-imaging light is incident on the second metal wire 105 and / or the side wall of the trench isolation structure 103, the non-imaging light is diffusely reflected by the concavo-convex surface, so that the non-imaging light is weakened and at least partially away from the pixel region 102.

[0074] Fig.16 A schematic diagram showing a planar structure of an image sensor according to another embodiment of the present invention; Fig.17 Shown along Fig.16 Schematic diagram of the cross-sectional structure along the B-B' section line.

[0075] Please combine Fig.16 refer to Fig.17 , except for the pixel region 102 , at least a portion of the top surface of the substrate 201 is configured as a concave-convex surface to diffusely reflect non-imaging light.

[0076] A dielectric structure 106 and another dielectric structure 107 are both disposed inside the substrate 201. Isolation structures of different shapes, sizes and materials are disposed according to the peripheral circuit area of ​​the pixel area 102. For example, the dielectric structure 106 and the dielectric structure 107 can be disposed on both sides of the pixel area 102 to shield light and / or heat from different depths.

[0077] like Fig.17 As shown, the top surface and side walls of the medium structure 106 are both configured as concave-convex surfaces. Even when non-imaging light at different angles is incident on the medium structure 106 , it can be diffusely reflected by the concave-convex surfaces arranged in different directions, thereby reducing the impact of the non-imaging light on the imaging area 102 .

[0078] Fig.18 A schematic diagram showing a planar structure of an image sensor according to another embodiment of the present invention; Fig.19 Shown along Fig.18 Schematic diagram of the cross-sectional structure along the C-C' section line.

[0079] Please combine Fig.18 refer to Fig.19 , a trench isolation structure 103 is provided in the substrate 100, and a concave-convex region 111 is provided in the substrate 100 between the trench isolation structure 103 and the pixel region 102, and the concave-convex region 111 has a concave-convex surface to diffusely reflect non-imaging light incident on the surface of the substrate 100. The concave-convex surface is at least located in the trench isolation structure 103 and the pixel region 102, or the trench isolation structure 103 can extend into the substrate 100 along the concave-convex surface.

[0080] Fig. 20 A schematic diagram showing a planar structure of an image sensor according to yet another embodiment of the present invention; Fig.21 Shown along Fig. 20 Schematic diagram of the cross-sectional structure along the D-D' section line.

[0081] Please combine Fig. 20 refer to Fig.21, a plurality of first groove structures are disposed in the substrate 100 outside the pixel region 102. The first groove structure 111 includes a first dielectric layer 1111 and a second dielectric layer 1112 disposed from outside to inside.

[0082] Through the patterning process, the side walls of the first dielectric layer 1111 and the second dielectric layer 1112 are both concave-convex surfaces.

[0083] Specifically, a first groove (not shown) having a concave-convex surface is formed in the substrate 102, and then the second dielectric layer 1112 having a concave-convex sidewall is formed in the first groove. Thereafter, the first groove is filled to form the first dielectric layer 1111 having a concave-convex sidewall, thereby forming a concave-convex surface having different and opposite heights and / or widths and / or lengths.

[0084] In another embodiment, the first dielectric layer 1111 is formed by a deposition process, the first dielectric layer 1111 covers the surface of the first groove having a concave-convex surface and has another concave-convex surface corresponding to the concave-convex surface of the first groove, and the first groove is filled to form a second dielectric layer 1112 having a concave-convex surface.

[0085] The second dielectric layer 1112 may be a third metal wire. The third metal wire may be higher than the first groove for electrical connection. An isolation material (not shown) is filled in the first groove to form the first dielectric layer 1111, so that the third metal wire is separated from the first metal wire 104 located on the substrate 100.

[0086] like Fig. 20 As shown, the bottom of the first groove may also be provided with a concave-convex bottom surface, and the concave-convex bottom surface is provided with a plurality of convex portions of equal or unequal width to surround the second dielectric layer 1112, and the concave-convex surface of the concave-convex side wall is provided with a plurality of convex portions of equal or unequal height, so that non-imaging light is diffusely reflected in the first groove structure 111.

[0087] The position of the first groove may be set according to the stress source. For example, in order to block and relieve stress from below the substrate 100, the first groove filled with the filling material and having a concave-convex surface may be set below (back side) or in an adjacent area of ​​the substrate 100. The present invention is not limited thereto. In some embodiments, at least one of the first grooves is correspondingly set directly below the first metal wire 104, that is, the vertical projection of at least one of the first grooves on the substrate is located within the vertical projection of the first metal wire 104 on the substrate, which can block and relieve stress of the substrate 100 in the peripheral circuit area.

[0088] In one embodiment, part or all of the sidewall of the first groove is set to a concave-convex surface, and a filling material is filled in the first groove to block and relieve the stress of the substrate 100 in the peripheral circuit area. According to specific needs, a plurality of first groove structures filled with different filling materials and having concave-convex surfaces can be set in certain designated areas of the peripheral circuit area.

[0089] The filling material can completely fill the first groove to form a solid structure. According to the opening size of the first groove, the filling material covers the sidewall and bottom of the first groove and quickly closes the top, thereby partially filling the first groove to form a hollow structure. The surface morphology of the filling layer formed by the deposition process is affected by the concave-convex surface of the first groove, so that the gap of the hollow structure also forms a concave-convex surface.

[0090] A plurality of dielectric structures may be arranged in the first groove. The material of the dielectric structure has a single crystal structure or a polycrystalline structure. At least one concave-convex surface is arranged between the two dielectric structures to reduce the stress between them. Among the two dielectric structures, part or all of the sidewalls of one dielectric structure are provided with a concave-convex surface, and part or all of the sidewalls of the other dielectric structure are provided with a concave-convex surface to reduce the stress between the two and diffusely reflect non-imaging light. Alternatively, according to the shape and size of the first groove, part of the sidewalls of one dielectric structure are provided with a concave-convex surface, and the surface of the remaining sidewalls is a curved surface or a flat surface to be opposite to or intersect with the concave-convex surface of the sidewall of the other dielectric structure.

[0091] like Fig. 20 As shown, the second groove structure 112 includes a third dielectric layer 1121 and a fourth dielectric layer 1122 arranged from outside to inside. The sidewalls of the fourth dielectric layer 1122 are both set as concave-convex surfaces, and the third dielectric layer 1121 is filled in the second groove (not shown) with straight sidewalls and bottom surface.

[0092] The third groove structure 113 includes a fifth dielectric layer 1131 and a sixth dielectric layer 1132 arranged from outside to inside. The sidewalls of the fifth dielectric layer 1131 are both set as concave-convex surfaces, and the fourth dielectric layer 1122 is filled in the third groove with concave-convex sidewalls (not shown).

[0093] like Fig.21 As shown, in the back-illuminated image sensor, an interconnection structure 109 is provided in the dielectric layer 101 below the substrate 100 (non-photosensitive surface), and a concave-convex surface can be provided on the top surface of the interconnection structure 109 , so that part of the non-imaging light is diffusely reflected on the surface of the interconnection structure 109 .

[0094] The interconnect structure 109 includes a plurality of metal layers (not shown) connected to each other by conductive vias, and the metal layers are arranged relative to each other so that the corresponding concave and convex surfaces are opposite to each other. The two concave and convex surfaces are arranged symmetrically, that is, the corresponding convex parts are opposite to each other. According to different metal materials, the sizes of the metal layers are different, for example, the line widths are different from each other. In order to ensure the effect of diffuse reflection, the arrangement density of the convex parts is different, so that the convex parts between the concave and convex surfaces can be staggered.

[0095] The present invention sets at least part of the surface of at least part of the medium structure outside the pixel area as a concave-convex surface, and the concave-convex surface diffusely reflects the incident non-imaging light, which on the one hand weakens the intensity of the reflected non-imaging light reaching the pixel area, and on the other hand changes the incident angle of the reflected non-imaging light, thereby avoiding the reflected non-imaging light from imaging and affecting the image effect.

[0096] Furthermore, the concave-convex surface is arranged on the side wall of the dielectric structure, and the concave-convex surface is defined during patterning in a photolithography process, which has the characteristic of simple manufacturing process.

[0097] Furthermore, at least one of the concave-convex surfaces is disposed between two adjacent dielectric structures to reduce stress between the two. Moreover, the number and arrangement of the concave-convex surfaces are flexibly set according to the layout area to improve the performance of the image sensor.

[0098] The present invention provides at least one concave-convex surface in the propagation path of non-imaging light. The non-imaging light is incident on the concave-convex surface to be diffusely reflected and away from the pixel area, so as to avoid the non-imaging light from imaging and affecting the image effect. At least one of the concave-convex surfaces is provided between two adjacent dielectric structures to reduce the stress between the two. Moreover, the number and arrangement of the concave-convex surfaces are flexibly set according to the layout area to improve the performance of the image sensor.

[0099] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, in any case, the embodiments should be considered exemplary and non-restrictive. Furthermore, it is apparent that the term "comprising" does not exclude other elements and steps, and the wording "a" does not exclude the plural. Multiple elements stated in a device claim may also be implemented by one element. The words first, second, etc. are used to indicate names and do not indicate any particular order.

Claims

1. An image sensor, characterized in that: include: At least one concave-convex surface is provided in the propagation path of the non-imaging light.

2. The image sensor according to claim 1, wherein: The concave-convex surface is arranged between different dielectric materials.

3. The image sensor according to any one of claims 1 or 2, characterized in that: The concave-convex surface is arranged on at least one side of the pixel area and has a plurality of convex parts.

4. The image sensor according to claim 3, wherein: The cross section of the convex portion is in the shape of a polygon or an arc, or a combination of the two.

5. The image sensor according to claim 4, wherein: The convex parts are arranged regularly or irregularly.

6. The image sensor according to claim 5, characterized in that The convex portions are arranged with equal or unequal distances between each other; and / or, the convex portions are arranged with equal or unequal heights between each other; and / or, the convex portions are arranged with equal or unequal widths between each other.

7. The image sensor according to claim 3, wherein: The pixel area is arranged in the substrate, and further comprises: at least one dielectric structure having at least one concave-convex surface and at least partially arranged on the substrate and / or in the substrate and / or under the substrate.

8. The image sensor according to claim 7, wherein: At least a portion of the surface of the medium structure is the concave-convex surface.

9. The image sensor according to claim 8, wherein: At least one dielectric layer covers the concave-convex surface.

10. The image sensor according to claim 7, wherein: The medium structure is a solid or hollow structure; and / or, the medium structure is a protrusion or a first groove.

11. The image sensor according to claim 10, wherein: Another or more medium structures having at least one concave-convex surface are disposed in the first groove.

12. The image sensor according to claim 7, wherein: At least one concave-convex surface is disposed between two adjacent medium structures.

13. The image sensor according to claim 12, wherein: The two medium structures are provided with two symmetrically or asymmetrically arranged concave and convex surfaces to face or intersect each other.

14. The image sensor according to claim 13, wherein: The convex parts between the two concave and convex surfaces are arranged opposite to each other or staggered.

15. The image sensor according to claim 12, wherein: The two medium structures are respectively provided with a concave-convex surface and a plane or a curved surface which are arranged opposite to or intersecting with each other.

16. The image sensor according to claim 7, wherein: The material of the dielectric structure includes one of a light blocking material and a light absorbing material.

17. The image sensor according to claim 7, wherein: The material of the dielectric structure has conductivity or insulation.

18. The image sensor according to claim 7, wherein: The material of the dielectric structure has a single crystal structure or a polycrystalline structure.

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