TW201814894A - Image sensor and fabrication method thereof - Google Patents

Abstract

An image sensor includes a photosensitive device, an interconnect structure, a dielectric stacked-layer, a reflective layer, and a barrier layer. The photosensitive device is disposed in the substrate. The interconnect structure is disposed on the surface of the substrate. The dielectric stacked-layer is disposed on the surface of the substrate and cover the photosensitive device, wherein the interconnect structure is disposed in the dielectric stacked-layer, and the top surface of the dielectric stacked-layer includes at least one protrusive portion disposed at one side of the photosensitive device. The reflective layer covers the protrusive portion of the dielectric stacked-layer, and the cross-sectional profile of the reflective layer includes an inverted V-shaped pattern or includes an inverted U-shaped pattern. The barrier layer covers the reflective layer.

Description

Image sensor and manufacturing method thereof

The invention relates to an image sensor and a manufacturing method thereof, and more particularly to an image sensor capable of improving cross talk and a manufacturing method thereof.

With the continuous development and growth of digital cameras, electronic scanners and other products, the demand for image sensing components in the market continues to increase. Currently commonly used image sensing elements include charge coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) image sensing elements (also known as CMOS image sensor, CIS) Two categories, CMOS image sensing devices have the advantages of low operating voltage, low power consumption, high operating efficiency, random access as needed, and the advantages of being integrated into current semiconductor technology and being manufactured in large quantities. The application range is very wide.

The CMOS image sensor's photosensitivity principle is to divide the incident light into a combination of several different wavelengths of light, such as red, blue, and green, and then each of a plurality of optical sensing elements on the semiconductor substrate, such as a photodiode ( photodiode) to receive and convert it into digital signals of different strengths. However, with the shrinking of the pixel size, the size of the photodiode has also been miniaturized, resulting in an increase in cross-talk between pixels and a decrease in photosensitivity. Therefore, how to provide an image sensor with low span interference is still a problem that the industry needs to continuously solve.

The invention provides an image sensor and a manufacturing method thereof, so as to improve the cross interference of the image sensor.

An embodiment of the present invention provides an image sensor, which includes a photosensitive element, an interconnect structure, a dielectric stack, a reflective layer, and a barrier layer. The photosensitive element is disposed in a substrate, and the interconnection structure is disposed on a surface of the substrate. The dielectric stack is disposed on the surface of the substrate and covers the photosensitive element, wherein the interconnect structure is disposed in the dielectric stack, and the top surface of the dielectric stack includes at least one protruding portion located on the photosensitive element. One side. The reflective layer covers the protruding portion of the dielectric stack, and the cross-sectional shape of the reflective layer includes an inverted V-shaped pattern or an inverted U-shaped pattern, and the barrier layer covers the reflective layer.

An embodiment of the present invention further provides a method for manufacturing an image sensor, which includes the following steps. First, a substrate is provided, and a photosensitive element is formed in the substrate. Next, an interconnect structure and a dielectric stack are formed on the surface of the substrate, wherein the interconnect structure is disposed in the dielectric stack, and a top surface of the dielectric stack includes a protruding portion on the photosensitive layer. One side of the component. Then, a patterned reflective layer is formed on the dielectric stack, the reflective layer covers at least the protruding portion of the dielectric stack, and the cross-sectional shape of the reflective layer includes an inverted V-shaped pattern or includes an inverted U Glyph pattern.

In order to make a person skilled in the art who is familiar with the technical field of the present invention better understand the present invention, the preferred embodiments of the present invention are enumerated below, and the accompanying drawings are used to describe the image sensor of the present invention and the manufacturing method thereof And the desired effect.

Please refer to FIG. 1 to FIG. 6, FIG. 1 to FIG. 5 are schematic diagrams showing the manufacturing process of the first embodiment of the image sensor manufacturing method of the present invention, and FIG. 6 is the method of manufacturing the image sensor of the present invention. The flowchart of the process steps of the first embodiment. According to this embodiment, as shown in FIG. 1, a substrate 100 is first provided. The substrate 100 has a pixel region 100X and a peripheral region 100Y, and the peripheral region 100Y is located on one side of the pixel region 100X. The substrate 100 may be a semiconductor substrate, such as a silicon substrate, an epitaxial silicon substrate, a silicon germanium substrate, a silicon carbide substrate, or a silicon-on-insulator (SOI) substrate, but is not limited thereto. Then, a plurality of photosensitive elements 102 and at least one switching element 104 are formed in the substrate 100. The photosensitive element 102 is disposed in the pixel area 100X and is located in the substrate 100 near the surface of the substrate 100. The photosensitive element 102 includes various elements capable of converting light energy into electrical energy, and may include, for example, a PN type photodiode, a PNP type photodiode, an NPN type photodiode, and the like, without being limited thereto. The switching element 104 is disposed on the surface of the substrate 100 in the peripheral region 100Y. The switching element 104 in this embodiment uses a metal-oxide-semiconductor field effect transistor (MOSFET) as an example, but is not limited thereto. In addition, a plurality of isolation structures 106 can be selectively formed in the substrate 100 and disposed in the peripheral region 100Y and the pixel region 100X (the first figure is shown in the peripheral region 100Y as a schematic diagram) to avoid the component phase in the substrate 100. Short circuit due to contact. It should be noted that the present invention does not specifically limit the manufacturing order and relative installation positions of the photosensitive element 102, the switching element 104, and the isolation structure 106.

Next, an interconnect structure and a dielectric stack are formed on the surface of the substrate 100. The dielectric stack covers the photosensitive element 102, the switching element 104, and the isolation structure 106, and the interconnect structure is disposed in the dielectric stack of the pixel region 100X and the peripheral region 100Y. The dielectric stack includes a plurality of interlayer dielectric layers 108, and the interconnect structure includes a plurality of interconnects 110. For example, a plurality of interconnect lines 110 may be formed on one interlayer dielectric layer 108 first, and then another interlayer dielectric layer 108 may be formed on the interconnect lines 110, and the above steps are repeated to form interconnects. Line structure and dielectric stack. In addition, the interconnects 110 of different layers can be connected in series through contact holes V1 in the interlayer dielectric layers 108 to form an interconnect structure, and the interconnects 110 located in the peripheral area 100Y can be formed by the interlayer dielectric layers 108. The contact hole V2 is electrically connected to the switching element 104. In this embodiment, the interlayer dielectric layer 108 is formed by a high-density plasma (HDP) chemical vapor deposition process. When the HDP chemical vapor deposition process is used to form the interlayer dielectric layer 108, a plurality of protrusions are formed on the surface of the interlayer dielectric layer 108, corresponding to the positions of the interconnect lines 110. Therefore, HDP chemical vapor deposition is used. When the lower interlayer dielectric layer 108 is manufactured, another planarization process (such as a chemical mechanical polishing process) may be performed so that the lower interlayer dielectric layer 108 has a flat surface. However, in the present invention, when the uppermost interlayer dielectric layer 108 is formed, no additional planarization process is performed, so as to retain the plurality of protruding portions 112 of the uppermost interlayer dielectric layer 108. In other words, the top surface of the dielectric stack of this embodiment includes a protruding portion 112, wherein the protruding portion 112 is disposed corresponding to the interconnect line 110 and is located on one side of the photosensitive element 102. In this embodiment, the distance D between the inner wiring 110 and the apex of the protruding portion 112 is several hundred nanometers, but it is not limited thereto. In addition, the shape of the protruding portion 112 may vary depending on the shape of the interconnector 110 disposed below it. For example, the width of the interconnecting line 110 in the pixel area 100X is narrow. The cross section of the protruding portion 112 in the pixel area 100X may have an inverted V-shaped pattern, and the interconnecting line 110 in the peripheral area 100Y. The width of the protrusion is relatively wide, so the protruding portion 112 in the peripheral region 100Y may include a flat surface, but is not limited thereto. In a modified embodiment, the cross section of the protruding portion 112 in the pixel region 100X may also have an inverted U-shaped pattern.

Next, as shown in FIG. 2, a reflective layer 114 ′ is formed on the substrate 100 in a comprehensive manner to cover the dielectric stack of the pixel region 100X and the peripheral region 100Y, and then a patterning process is performed on the reflective layer 114 ′, for example, a In the photolithography and etching process, a photoresist layer 142 is coated on the reflective layer 114 ', and then exposed and developed to pattern the photoresist layer 142 so that the patterned photoresist layer 142 corresponds to and covers the protrusions of the pixel area 100X. The portion 112 exposes the photosensitive element 102 and the peripheral region 100Y. As shown in FIG. 3, the reflective layer 114 ′ exposed by the photoresist layer 142 is removed to form a patterned reflective layer 114. The reflective layer 114 covers at least the protruding portion 112 but does not cover the peripheral area 100Y. In addition, the reflective layer 114 covers the protruding portion 112 stepwise and fluctuates in accordance with the height of the covered protruding portion 112. Since the cross-sectional shape of the protruding portion 112 in the pixel region 100X is an inverted V-shaped pattern, the sectional shape of the reflective layer 114 also includes an inverted V-shaped pattern. In a modified embodiment, when the cross-sectional shape of the protruding portion 112 in the pixel region 100X is an inverted U-shaped pattern, the cross-sectional shape of the reflective layer 114 covered thereon also includes an inverted U-shaped pattern, or other narrow tops. Wide pattern. For example, the material of the reflective layer 114 may include a metal material, such as tungsten, but is not limited thereto. The thickness of the reflective layer 114 in this embodiment is tens of nanometers, but it is not limited thereto. After the reflective layer 114 is formed, a dielectric layer 116 is completely formed on the pixel region 100X and the peripheral region 100Y, and a planarization process such as a chemical mechanical polishing process is performed so that the pixel region 100X and the peripheral region 100Y have a flat surface. The material of the dielectric layer 116 and the interlayer dielectric layer 108 may include a low-K dielectric material, such as silicon oxide, borophosphosilicate glass (BPSG), and silicon silicon. Phosphosilicate glass (PSG), fluorinated silicate glass (FSG), carbon-doped silicon oxide (carbon-doped silicon oxide) or the like are not limited thereto.

Next, as shown in FIG. 4, a patterned reflective layer 114 is used as an etching mask, and a lithography process is performed on the dielectric stack to remove the dielectric layer 116 and part of the dielectric in the pixel area 100X. They are stacked so that a light pipe opening 118 is formed on each photosensitive element 102, and a portion of the dielectric stack covered by the reflective layer 114 is retained. The light pipe opening 118 may be, for example, an opening that is wide at the top and narrow at the bottom, but is not limited thereto. In addition, before performing the etching process in this embodiment, a photoresist layer 120 is formed on the dielectric layer 116 in the peripheral region 100Y to prevent the dielectric layer 116 in the peripheral region 100Y from being affected by the etching process, and the photoresist layer 120 can be removed after the etching process, and the peripheral region 100Y still has a flat surface.

Next, as shown in FIG. 5, a barrier layer 122 is formed on the substrate 100, which covers the bottom and side walls of the light pipe opening 118 in the pixel area 100X, and also covers the reflective layer 114, and covers the surrounding area 100Y. Dielectric layer 116. The material of the barrier layer 122 may include silicon nitride, silicon oxynitride, or other suitable dielectric materials. Then, each light pipe opening 118 is filled with a high refractive index material layer to form a light pipe 124. The high refractive index material layer can be subjected to a planarization process to make the pixel region 100X have a flat surface. The cross-sectional shape of the light pipe 124 in this embodiment is a funnel-shaped pattern, and the material of the light pipe 124 is a photoresist material or a photoresist-like material, but it is not limited thereto. In a preferred embodiment, the refractive index of the material of the light pipe 124 is higher than the refractive index of the barrier layer 122, and the refractive index of the barrier layer 122 is higher than the refractive index of the dielectric stack. Next, an insulating layer 126 is formed on the pixel region 100X and the peripheral region 100Y, covering the light pipe 124, the barrier layer 122 and the dielectric layer 116, and the insulating layer 126 has a substantially flat top surface. For example, the insulating layer 126 in this embodiment is made of a low-temperature-oxide (LTO) material. Then, a plurality of different color filter layers 128R, 128G, and 128B are formed on the insulating layer 126 to cover the corresponding photosensitive elements 102 and light pipes 124, respectively. The color filter layers 128R, 128G, and 128B of this embodiment are provided only in the pixel area 100X. The color filter layers 128R, 128G, and 128B may include, for example, colored photoresist patterns, and may be fabricated by a photolithography process. For example, the color filter layers 128R, 128G, and 128B may include red, blue, or green filter materials, so that the photosensitive element 102 can sense light of a specific color. Then, a plurality of micro-condensing mirrors 130 are formed on each of the color filter layers 128R, 128G, and 128B to cover the photosensitive elements 102 and the light pipes 124 below them. In addition, the micro-condensing mirror 130 may be disposed in the peripheral region 100Y to cover the insulating layer 126.

In addition, before the color filter layers 128R, 128G, and 128B are formed and after the micro-condenser 130 is formed, an etching process may be separately performed to form a wire opening 132 corresponding to the interconnect line 110 in the peripheral area 100Y, so that subsequent wires can be borrowed The wire opening 132 is electrically connected to the inner wiring 110.

In summary, the method for manufacturing the image sensor 1 according to the present invention mainly includes the steps shown in FIG. 6:

Step S10: providing a substrate and forming a photosensitive element on the substrate;

Step S12: forming an interconnect structure and a dielectric stack on the surface of the substrate, wherein the interconnect structure is disposed in the dielectric stack, and the top surface of the dielectric stack includes a protruding portion on one side of the photosensitive element ;as well as

Step S14: forming a reflective layer on the dielectric stack, which at least covers the protruding portion of the dielectric stack, and the cross-sectional shape of the reflective layer includes an inverted V-shaped pattern or an inverted U-shaped pattern.

Please continue to refer to FIG. 5. The image sensor 1 of this embodiment includes a photosensitive element 102, an interconnect structure, a dielectric stack, a reflective layer 114, and a barrier layer 122. The photosensitive element 102 is disposed in the substrate 100. The dielectric stack is disposed on the surface of the substrate 100 and covers the photosensitive element 102, and the interconnect structure is disposed in the dielectric stack. The dielectric stack of this embodiment includes a plurality of interlayer dielectric layers 108, and the interconnect structure includes a plurality of interconnects 110 and a contact plug disposed in the contact hole V1. The top surface of the dielectric stack includes at least one protruding portion 112, which is disposed corresponding to the interconnect line 110 and is located on one side of the photosensitive element 102. The reflective layer 114 covers the protruding portion 112 of the dielectric stack and fluctuates with the covered protruding portion 112. Therefore, the cross-sectional shape of the reflective layer 114 is an inverted V-shaped pattern or an inverted U-shaped pattern, and the barrier layer 122 covers On the reflective layer 114 and in direct contact with the reflective layer 114. In addition, the image sensor 1 may be further provided with a switching element 104, such as a MOS transistor, in the peripheral region 100Y, and a pixel circuit (not shown) may be disposed in the peripheral region 100Y. For other components and materials of the first embodiment of the image sensor 1 of the present invention, reference may be made to the description of the foregoing process, and details are not described herein again.

Please continue to refer to FIG. 5. In the following, light L1 and L2 will be used to explain how the reflective layer 114 of this embodiment achieves the effect of reducing cross-talk. As shown in FIG. 5, the light rays L1 and L2 pass through the color filter layer 128R in the image sensor 1, but the light rays L1 and L2 pass through the color filter layer 128R and do not face the photosensitive element corresponding to the color filter layer 128R. 102 advances, but advances to the adjacent photosensitive element 102. In this embodiment, a reflective layer 114 is provided on the dielectric stack on one side of the photosensitive element 102, so that the light rays L1 and L2 that originally moved toward the adjacent photosensitive element 102 will first travel to the reflective layer 114 and then be reflected. The layer 114 reflects to change the travel path to avoid being absorbed by the adjacent photosensitive element 102. It can be known from the foregoing that the image sensor 1 has a reflective layer 114 on the dielectric stack between adjacent photosensitive elements 102, and the cross-sectional shape of the reflective layer 114 is an inverted V-shaped pattern or an inverted U-shaped pattern. When light passes through one of the color filter layers 128R, 128G, or 128B and proceeds toward the photosensitive element 102 corresponding to the other color filter layer 128R, 128G, or 128B, it will be reflected by the reflective layer 114 to change the travel path to prevent it Adjacent photosensitive elements 102 can effectively reduce the cross-talk of the image sensor 1.

The image sensor and the manufacturing method of the present invention are not limited to the above embodiments. The following will continue to disclose other embodiments and variations of the present invention, but in order to simplify the description and highlight the differences between the embodiments, the same elements are labeled with the same reference numerals in the following, and the repeated parts will not be repeated.

Please refer to FIG. 7 and FIG. 8, which are process schematic diagrams of a modified embodiment of the first embodiment of the image sensor manufacturing method of the present invention, and FIG. 8 shows an image of the modified embodiment of the first embodiment of the present invention. A schematic cross-sectional view of the sensor 2. As shown in FIG. 7, it illustrates the process following FIG. 4. The difference between this modified embodiment and the first embodiment is that the barrier layer 122 is sequentially formed and the light pipe opening 118 is filled with high After the refractive index material layer is formed to form the light pipe 124, a step is added to remove the high refractive index material layer on the top of the light pipe 124. For example, after the high refractive index material layer is planarized by chemical mechanical polishing, an etch back process is further performed, The height of the top surface of the light pipe 124 is lower than a portion of the barrier layer 122 covering the protruding portion 112. As shown in FIG. 8, an insulating layer 126 is formed on the light pipe 124 and the barrier layer 122. Since the top of the light pipe 124 has been removed, the subsequently formed insulating layer 126 covers the barrier layer 122 and the surface of the light pipe 124 in steps, and the surface of the insulating layer 126 forms a plurality of grooves 140, which are respectively located in each light pipe. Above 124. The cross-sectional shape of the groove 140 in this modified embodiment is an inverted trapezoid, but it is not limited thereto. Then, a color filter layer 128 is filled in each of the grooves 140 to cover a corresponding photosensitive element 102 respectively, and the color filter layer 128 and a part of the insulating layer 126 have a flat top surface by a planarization process. Next, a micro condenser 130 is formed on the color filter layer 128. With the manufacturing method of this modified embodiment, the color filter layer 128 of the image sensor 2 is embedded in the groove 140 of the insulating layer 126, which can further reduce the overall thickness of the image sensor 2. In addition, the positions, materials, and manufacturing methods of the remaining components in the image sensor 2 can be referred to the first embodiment, and therefore will not be described again.

Please refer to FIG. 9 and FIG. 10, which are schematic process diagrams of a second embodiment of a method for manufacturing an image sensor according to the present invention, and FIG. 10 illustrates a schematic cross-sectional view of the image sensor 3 according to the second embodiment of the present invention. Figure 9 is the process following Figure 3. As shown in FIG. 9, this embodiment is different from the first embodiment in that, after the patterned reflective layer 114 and the dielectric layer 116 are fabricated, a patterned pattern is formed before the pixel region 100X and the peripheral region 100Y. The photoresist layer 120 defines a light pipe opening pattern 134 in the pixel area 100X to expose a part of the dielectric layer 116 on the photosensitive element 102 and covers the protruding portion 112, and the patterned photoresist layer 120 covers the peripheral area 100Y. Dielectric layer 116. Then, the photoresist layer 120 is used as an etching mask to perform an etching process, and the dielectric layer 116 and the dielectric stack that are not covered by the photoresist layer 120 are removed to form a light pipe opening 118 corresponding to each photosensitive element 102. A portion of the dielectric layer 116 covered by the photoresist layer 120 is left behind and forms a plurality of cap layers 136. The cap layer 136 covers the reflective layer 114 on the protruding portion 112, and has a substantially flat top surface and a substantial surface. The upper side wall is perpendicular to the surface of the substrate 100. In other words, the material of the top cover layer 136 of the image sensor 3 in this embodiment is the same as that of the dielectric layer 116. Next, as shown in FIG. 10, a barrier layer 122 is formed on the pixel area 100X and the peripheral area 100Y, and the step covers the top surface and the side wall of the top cover layer 136, and the step covers the reflective layer 114 not covered by the top cover layer 136. section. Then, a high refractive index material layer is filled into the light pipe opening 118, and then a chemical mechanical polishing process is selectively performed so that the top of the high refractive index material layer and the top surface of the barrier layer 122 on the cap layer 136 are substantially Coplanar to form the light pipe 124. After that, referring to the first embodiment, an insulating layer 126, a color filter layer 128, and a micro-condenser 130 are formed, and a wire opening 132 is formed in the peripheral area 100Y to complete the fabrication of the image sensor 3 in this embodiment.

Please refer to FIG. 11 and FIG. 12, which are process schematic diagrams of a modified embodiment of the second embodiment of the image sensor manufacturing method of the present invention, and FIG. 12 shows an image of the modified embodiment of the second embodiment of the present invention. A schematic cross-sectional view of the sensor 4. As shown in FIG. 11, this modified embodiment is different from the second embodiment in that after the barrier layer 122 is sequentially formed and a high refractive index material layer is filled in the light pipe opening 118 to form the light pipe 124, Add a step to remove the high refractive index material layer on the top of the light pipe 124, for example, after planarizing the high refractive index material layer by chemical mechanical polishing, further perform an etch-back process so that the height of the top surface of the light pipe 124 is lower than the top cover The top surface of the layer 136 exposes a portion of the barrier layer 122 covering the sidewall of the capping layer 136. Next, as shown in FIG. 12, an insulating layer 126 is formed on the substrate 100 to cover the light pipe 124 and the barrier layer 122 in steps. Since the top of the light pipe 124 has been removed, a plurality of grooves 140 are formed on the surface of the insulating layer 126 formed subsequently, which are respectively located above the light pipes 124. The cross-sectional shape of the groove 140 in this modified embodiment is substantially rectangular, but is not limited thereto. Then, a color filter layer 128 is formed in each of the grooves 140 to cover each of the photosensitive elements 102, wherein the color filter layer 128 and the insulating layer 126 on the top cover layer 136 can have flat tops by a planarization process. And the top surfaces of the two are substantially coplanar. Next, a micro-condenser 130 is formed on the color filter layer 128, and a wire opening 132 is formed in the peripheral region 100Y. With the manufacturing method of this modified embodiment, the color filter layer 128 of the image sensor 4 is embedded in the groove 140 of the insulating layer 126, which can further reduce the overall thickness of the image sensor 4.

Please refer to FIG. 13 to FIG. 15, which are schematic process diagrams of a third embodiment of an image sensor manufacturing method according to the present invention, and FIG. 15 is a schematic cross-sectional view of an image sensor 5 according to a third embodiment of the present invention. In the third embodiment, FIG. 13 is a process following FIG. 3. As shown in FIG. 13, this embodiment is different from the first embodiment in that, after the dielectric layer 116 is formed on the reflective layer 114 and the dielectric stack, a patterned photoresist layer 120 is formed first, wherein the photoresist The opening of the layer 120 corresponds to the protruding portion 112. Next, an etching process is performed to remove a part of the dielectric layer 116 not covered by the photoresist layer 120 to expose a part of the reflective layer 114 on the protruding pattern 112, and a cap layer opening 138 is formed on each reflective layer 114.

Then, as shown in FIG. 14, the capping layer 146 formed in the capping layer opening 138 covers each protruding portion 112 and the reflective layer 114 thereon. The method of forming the cap layer 146 in this embodiment may include removing the photoresist layer 120 first, then filling a metal material (such as tungsten) into the cap layer opening 138 in the dielectric layer 116, and then using the dielectric layer 116 as The chemical mechanical polishing process is performed as a polishing stop layer, so that the cap layer 146 has a substantially flat top surface and is substantially coplanar with the top surface of the dielectric layer 116. In addition, the capping layer 146 has a sidewall substantially perpendicular to the surface of the substrate 100. Next, a photoresist layer 144 is formed on the peripheral region 100Y to cover the dielectric layer 116 of the peripheral region 100Y, and then the cap layer 146 and the reflective layer 114 are used as an etching mask to the dielectric layer 116 and the dielectric of the pixel region 100X. The electrical stack is etched to form a light pipe opening 118 between the reflective layers 114.

Next, as shown in FIG. 15, the photoresist layer 144 in the peripheral region 100Y is removed, and then a barrier layer 122 is formed on the substrate 100 in its entirety. The barrier layer 122 covers the top surface and the side walls of the top cover layer 146 and the reflection in steps. The layer 114 covers the dielectric layer 116 of the peripheral region 100Y. For the manufacturing methods, locations, and materials of the remaining components of the image sensor 5 in this embodiment, reference may be made to the first embodiment, and details are not described herein again. Compared with the second embodiment, since the material of the cap layer 146 in this embodiment is metal, both the side wall and the top surface thereof can provide a reflection effect, which can further reduce the situation of cross interference.

Please refer to FIG. 16, which illustrates a schematic cross-sectional view of a modified embodiment of the third embodiment of the image sensor manufacturing method of the present invention. The difference between the image sensor 6 and the third embodiment of this modified embodiment lies in light. The top surface of the conduit 124 is lower than the top surface of the capping layer 146. Therefore, a groove 140 is formed on the surface of the subsequent insulating layer 140, and the color filter layer 128 is filled in the groove 140. For the manufacturing method, refer to the eleventh above. Figure and Figure 12. Furthermore, the difference between this modified embodiment and the modified embodiment of the second embodiment (FIG. 12) is that the material of the cap layer 146 is a metal material, and the cap layer 136 of FIG. 12 is a dielectric material. With the manufacturing method of this modified embodiment, the color filter layer 128 is embedded in the groove 140 of the insulating layer 126 and is located between two adjacent top cover layers 146. Therefore, the color filter layer 128 faces the adjacent photosensitive The light traveling through the element 102 can be effectively reflected by the top surface and the side wall of the top cover layer 146, thereby effectively reducing the cross interference of the image sensor. In addition, for the positions, materials, and manufacturing methods of the remaining components in the image sensor, reference may be made to the modified embodiment of the second embodiment, and details are not described herein again.

In summary, the top surface of the dielectric stack of the image sensor of the present invention includes at least one protruding portion on one side of the photosensitive element, and reflective layers are provided on the protruding portions on both sides of the photosensitive element. Examples of materials are metallic materials. When the lateral light passes through the color filter layer and advances to the adjacent interconnecting structure or photosensitive element, it will be reflected by the reflective layer to change the travel path to prevent the light from being absorbed by the adjacent photosensitive element, thereby reducing the image perception. Tester's cross interference problem. In addition, the image sensor of the present invention may further include a top cover layer disposed on the reflective layer, which has a flat top surface and a side wall, and the material thereof may be metal, so light may be reflected by the top surface and the side wall of the top cover layer. Therefore, the top cover layer can be used as a retaining wall disposed between adjacent sensing elements, which can more effectively reduce the cross-interference situation of the image sensor. In addition, the color filter layer of the image sensor of the present invention can also be embedded in a groove on the surface of the insulating layer, so that the color filter layer is located between two adjacent reflective layers or the top cover layer to reduce the color filter. The distance between the layer and the photosensitive element can reduce the amount of light traveling across the pixels, while further reducing the overall thickness of the image sensor. The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the scope of patent application of the present invention shall fall within the scope of the present invention.

1, 2, 3, 4, 5, 6‧‧‧ image sensors

100‧‧‧ substrate

100X‧‧‧Pixel Area

100Y‧‧‧Peripheral area

102‧‧‧photosensitive element

104‧‧‧switching element

106‧‧‧Isolation structure

108‧‧‧ Interlayer dielectric layer

110‧‧‧Internal connection

112‧‧‧ protrusion

114、114’‧‧‧Reflective layer

116‧‧‧ Dielectric layer

118‧‧‧light pipe opening

120, 142, 144‧‧‧ photoresist layer

122‧‧‧Barrier layer

124‧‧‧light pipe

126‧‧‧ Insulation

128, 128R, 128G, 128B‧‧‧ color filters

130‧‧‧Micro Condenser

132‧‧‧Wire opening

134‧‧‧light pipe opening pattern

136, 146‧‧‧ roof

138‧‧‧ top cover opening

140‧‧‧Groove

D‧‧‧distance

L1, L2‧‧‧‧light

V1, V2‧‧‧ contact hole

FIG. 1 to FIG. 5 are schematic diagrams illustrating a manufacturing process of a first embodiment of a method for manufacturing an image sensor according to the present invention. FIG. 6 is a flowchart of the manufacturing process steps of the first embodiment of the image sensor manufacturing method of the present invention. FIG. 7 to FIG. 8 are schematic diagrams illustrating a manufacturing process of a modified embodiment of the first embodiment of the method for manufacturing an image sensor according to the present invention. FIG. 9 to FIG. 10 are schematic diagrams illustrating the manufacturing process of the second embodiment of the image sensor manufacturing method of the present invention. FIG. 11 to FIG. 12 are schematic diagrams illustrating a manufacturing process of a modified embodiment of the second embodiment of the image sensor manufacturing method of the present invention. 13 to 15 are schematic diagrams showing the manufacturing process of the third embodiment of the image sensor manufacturing method of the present invention. FIG. 16 is a schematic cross-sectional view of a modified embodiment of the third embodiment of the image sensor of the present invention.

Claims (17)

An image sensor includes: a photosensitive element disposed in a substrate; an interconnect structure disposed on a surface of the substrate; a dielectric stack disposed on the surface of the substrate and covering the photosensitive element, wherein the inside The wiring structure is disposed in the dielectric stack, and the top surface of the dielectric stack includes at least one protruding portion on one side of the photosensitive element; a reflective layer covering the protruding portion of the dielectric stack, and The cross-sectional shape of the reflective layer includes an inverted V-shaped pattern or includes an inverted U-shaped pattern; and a barrier layer covering the reflective layer. The image sensor according to claim 1, further comprising a capping layer disposed between the barrier layer and the reflective layer, wherein the capping layer has a substantially flat top surface and is perpendicular to the substrate surface Side walls, and the barrier layer covers the top cover layer and the reflective layer in steps. The image sensor according to claim 2, wherein the capping layer comprises a metal material or an insulating material. The image sensor according to claim 1 or 2, further comprising: an insulating layer disposed on the barrier layer and covering the barrier layer in steps, and a groove formed on a surface of the insulating layer corresponding to the photosensitive layer An element; a color filter layer filled in the groove; and a micro condenser lens disposed on the color filter layer and corresponding to the photosensitive element. The image sensor according to claim 4, wherein a cross-sectional shape of the groove includes an inverted trapezoid or a rectangle. The image sensor according to claim 1, further comprising: an insulating layer disposed on the barrier layer, the insulating layer having a substantially flat top surface; a color filter layer disposed on the insulating layer And a micro condenser lens, which is disposed on the color filter layer and corresponding to the photosensitive element. The image sensor according to claim 1, further comprising a light pipe disposed on the photosensitive element and located in the dielectric stack, and a part of the barrier layer is provided on the light pipe and the dielectric stack. Between layers. A method for manufacturing an image sensor includes: providing a substrate and forming a photosensitive element in the substrate; forming an interconnect structure and a dielectric stack on a surface of the substrate, wherein the interconnect structure is disposed on In the dielectric stack, and a top surface of the dielectric stack includes a protruding portion on one side of the photosensitive element; and forming a patterned reflective layer on the dielectric stack, the reflective layer covering at least the The protruding portion of the dielectric stack, and the cross-sectional shape of the reflective layer includes an inverted V-shaped pattern or includes an inverted U-shaped pattern. The method for manufacturing an image sensor according to claim 8, further comprising: removing a part of the dielectric stack to form a light pipe opening on the photosensitive element; forming a barrier layer on the substrate to cover A bottom and a side wall of the light pipe opening cover the reflective layer; a light pipe is formed in the light pipe opening; an insulation layer is formed on the light pipe and the barrier layer; and an insulation layer is formed on the insulation layer A color filter layer covers the photosensitive element; and a micro condenser lens is formed on the color filter layer to cover the photosensitive element. The method for manufacturing the image sensor according to claim 9, further comprising forming a capping layer on the reflective layer before forming the barrier layer, the capping layer having a substantially flat top surface and The sidewalls perpendicular to the surface of the substrate, and the barrier layer formed later cover the reflective layer and the cap layer. The method for manufacturing an image sensor according to claim 10, wherein the capping layer comprises a metal material, and the method of forming the light pipe opening includes using the capping layer and the reflective layer as an etching mask, and An etching process is performed on the dielectric stack to remove a portion of the dielectric stack exposed by the cap layer and the reflective layer. The method for manufacturing an image sensor according to claim 9, wherein the method for forming the light pipe opening includes using the reflective layer as an etching mask, and performing an etching process on the dielectric stack to remove the reflection. The exposed portion of the layer is the dielectric stack. The method for manufacturing an image sensor according to claim 9, wherein the barrier layer step covers the reflective layer and directly contacts the reflective layer. The method for manufacturing an image sensor according to claim 9, wherein the insulating layer covers the barrier layer in steps, a groove is formed on the surface of the insulating layer corresponding to the photosensitive element, and the color filter layer is filled in Inside the groove. The method for manufacturing an image sensor according to claim 14, wherein a cross-sectional shape of the groove includes an inverted trapezoid or a rectangle. The method for manufacturing an image sensor according to claim 9, wherein the insulating layer has a substantially flat top surface. The method for manufacturing an image sensor according to claim 8, wherein the method for forming the dielectric stack includes performing a high density plasma (HDP) chemical vapor deposition process.