TWI615957B - Image sensor and fabrication method thereof - Google Patents

Abstract

The invention provides an image sensor, which includes a photosensitive element, at least one patterned conductive layer, at least a lower dielectric layer, at least one optical barrier layer, and at least one upper dielectric layer. The photosensitive element is disposed on a substrate surface, the patterned conductive layer is disposed on the substrate, and the patterned conductive layer includes at least one interconnect line and is disposed on one side of the photosensitive element. The lower dielectric layer is disposed on the substrate and covers the interconnects. The optical barrier layer covers the lower dielectric layer. The upper dielectric layer covers the optical barrier layer. The refractive index of the optical barrier layer is greater than that of the upper dielectric layer and the lower dielectric layer. Refractive index.

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, which utilize an optical barrier layer provided in the image sensor to improve the cross-talk of the image sensor.

According to an embodiment of the present invention, the present invention provides an image sensor including a photosensitive element, at least one patterned conductive layer, at least a lower dielectric layer, at least one optical barrier layer, and at least one upper dielectric layer. The photosensitive element is disposed on a substrate surface. The patterned conductive layer is disposed on the substrate, and the patterned conductive layer includes at least one interconnect line and is disposed on one side of the photosensitive element. The lower dielectric layer is disposed on the substrate and covers the interconnects. The optical barrier layer covers the lower dielectric layer and the upper dielectric layer covers the optical barrier layer. The refractive index of the optical barrier layer is greater than that of the upper dielectric layer and the lower dielectric layer. Refractive index.

According to an embodiment of the present invention, the present invention provides a method for manufacturing an image sensor, which includes the following steps. First, a substrate is provided, and a photosensitive element is formed on the surface of the substrate. Then, a patterned conductive layer is formed on the substrate. The patterned conductive layer includes at least one interconnect and is disposed on one side of the photosensitive element. Next, a dielectric layer is formed on the patterned conductive layer, and the stepped layer covers the patterned conductive layer. Then, an optical barrier layer is formed on the substrate and the lower dielectric layer is covered stepwise, and then an upper dielectric layer is formed on the substrate and the optical barrier layer is formed. The refractive index of the optical barrier layer is greater than that of the upper dielectric layer and the lower dielectric layer. Refractive index of the electrical layer.

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. 8. FIG. 1 to FIG. 7 are schematic diagrams showing a manufacturing process of the first embodiment of the image sensor manufacturing method of the present invention, and FIG. 8 is a 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 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 layer. -on-insulator (SOI) substrate, but not limited to this. Then, a plurality of photosensitive elements 102 are formed on the surface of the substrate 100. The photosensitive element 102 includes various elements capable of converting light energy into electric energy. For example, the photosensitive element 102 may include a PN type photodiode, a PNP type photodiode, an NPN type photodiode, and the like. For example, the photosensitive element 102 of this embodiment may be a PNP type photodiode. The formation method is, for example, implanting a P-type dopant and an N-type dopant into the substrate 100 by an ion implantation process. A specific region in the P-type doped region is formed on an N-type doped region, and the N-type doped region is formed on a P-type substrate, but not limited thereto.

Next, a plurality of gates (not shown) are selectively formed on the substrate 100. The gate electrodes may be formed respectively corresponding to one photosensitive element 102 and disposed on one side of the corresponding photosensitive element 102. The material of the gate electrode may include polysilicon or metal materials, but is not limited thereto. For example, the gate of this embodiment may be, for example, a transfer gate (Tx) of the image sensor 1A. In addition, a gate insulating layer (not shown) may be formed between the gate and the substrate 100, or a plurality of isolation structures 144 may be selectively formed before the substrate 100 before the gate and the gate insulating layer are formed. The isolation structure 144 may be a shallow trench isolation (STI) or a local oxidation of silicon isolation layer (LOCOS) to prevent the photosensitive element 102 from contacting other elements and causing a short circuit. It should be noted that the present invention does not specifically limit the manufacturing order and relative positions of the photosensitive element 102, the gate and the gate insulating layer, and the isolation structure 144.

Next, an insulating layer 106 is formed on the substrate 100 to cover the gate electrode. The material of the insulating layer 106 in this embodiment is silicon dioxide, but it is not limited thereto. The material of the insulating layer 106 may be a low-K dielectric material, such as silicon oxide, borophosphosilicate glass (BPSG), phosphosilicate glass, PSG), fluorinated silicate glass (FSG), carbon-doped silicon oxide, or the like. The method for forming the insulating layer 106 is, for example, chemical vapor deposition (CVD) technology, but is not limited thereto. Thereafter, a chemical mechanical polishing (CMP) process can be used to make the insulating layer 106 have a flat surface. Then, a patterned conductive layer is formed on the insulating layer 106. The patterned conductive layer includes a plurality of interconnecting lines 112. For example, the material of the interconnect 112 may be aluminum, copper, doped polysilicon, or the like. In addition, the cross-sectional pattern of the interconnect line 112 in this embodiment is trapezoidal, but it is not limited thereto.

As shown in FIG. 2, an interlayer dielectric layer 114 is formed on the patterned conductive layer, and the interlayer dielectric layer 114 covers the interconnector 112 and the photosensitive element 102 located below it. The interlayer dielectric layer 114 in this embodiment may be an inter-metal dielectric layer. The material is exemplified by silicon dioxide, but it is not limited thereto. The material of the interlayer dielectric layer 114 may also be other materials. A low-K dielectric material, such as the material of the insulating layer 106 mentioned in the previous paragraph. The method for forming the interlayer dielectric layer 114 is, for example, a CVD process and a CMP process, but it is not limited thereto. In this embodiment, the above steps can be repeated to successively form multiple interlayer dielectric layers 114 and patterned conductive layers, and the interconnects 112 of each of the patterned conductive layers can pass through the contact holes 116 in each of the interlayer dielectric layers 114. The series connection forms a multilayer interconnect (MLI) structure.

Referring to FIG. 3, a dielectric layer 118 is formed on the uppermost patterned conductive layer. The lower dielectric layer 118 covers the patterned conductive layer in a stepwise manner, that is, the lower dielectric layer 118 will be covered by it. The interconnector 112 rises and falls. Then, an optical barrier layer 120 is formed on the lower dielectric layer 118, and the optical barrier layer 120 covers the lower dielectric layer 118 in steps, and fluctuates with the covered lower dielectric layer 118. The optical barrier layer 120 and the lower dielectric layer 118 can be selected according to the materials included in them, such as chemical vapor deposition or physical vapor deposition. There is an interface between the optical barrier layer 120 and the lower dielectric layer 118, which fluctuates with the patterned conductive layer covered by the lower dielectric layer 118 and the optical barrier layer 120. Therefore, the interface includes a plurality of side portions 124 and a plurality of平面 部 126。 The flat portion 126. In addition, since the cross-sectional pattern of the interconnect line 112 in this embodiment is trapezoidal, the side surface portion 124 of the interface is an inclined surface, and the extension line thereof is less than 90 degrees from the surface of the substrate 100 or the top surface of the uppermost interlayer dielectric layer 114. Angle α. In addition, the refractive index of the optical barrier layer 120 is greater than the refractive index of the lower dielectric layer 118. For example, the material of the dielectric layer 118 is silicon dioxide with a refractive index of 1.45, and the material of the optical barrier layer 120 is silicon nitride (SiN) with a refractive index of 1.99. This is limited. The material of the lower dielectric layer 118 may also be selected from the materials included in the above-mentioned insulating layer 106. When the material of the lower dielectric layer 118 is silicon dioxide, the material of the optical barrier layer 120 may also be silicon carbide (refractive index 2.6), aluminum (refractive index 2.7), silicon (refractive index 3.44), tungsten (Refractive index is 3.53) or other materials with a refractive index greater than silicon dioxide. When silicon nitride or silicon carbide is selected as the material of the optical barrier layer 120, the advantage is that these materials can be integrated with other semiconductor processes of the CMOS device, which can save process costs.

Then, as shown in FIG. 4, an upper dielectric layer 128 is formed on the optical barrier layer 120, and the refractive index of the upper dielectric layer 128 is smaller than the refractive index of the optical barrier layer 120. According to this embodiment, the upper dielectric layer 128 preferably fills or even exceeds the recessed portion of the optical barrier layer 120. For example, a thicker upper dielectric layer 128 is first formed by the CVD process to completely cover the optical barrier layer 120, and then chemically The mechanical polishing process planarizes the surface of the upper dielectric layer 128. The material of the upper dielectric layer 128 in this embodiment is silicon dioxide, but it is not limited thereto. The material of the upper dielectric layer 128 may also be selected from the materials included in the above-mentioned insulating layer 106.

As shown in FIG. 5, a patterned masking layer 130 is formed on the surface of the upper dielectric layer 128. The patterned masking layer 130 in this embodiment has a plurality of openings to define positions of the plurality of light pipe openings, and the openings of the patterned masking layer 130 are preferably disposed corresponding to the photosensitive element 102. The patterned mask layer 130 in this embodiment is exemplified by a photoresist material, but is not limited thereto. Then, an etching process 132 is performed using the patterned mask layer 130 as an etching mask to remove portions of the upper dielectric layer 128, the optical barrier layer 120, the lower dielectric layer 118, and the interlayer dielectric layer thereunder. 114. A light pipe opening 134 is formed on each photosensitive element 102. Then, the patterned masking layer 130 is removed after the light pipe opening 134 is formed.

As shown in FIG. 6, a barrier layer 136 may be selectively formed on the bottom surface and the sidewall surface of the light pipe opening 134. The material of the barrier layer 136 in this embodiment is silicon nitride, but it is not limited thereto. In other embodiments, the material of the barrier layer 136 may include silicon oxynitride or other suitable dielectric materials. Then, a high-refractive-index material is filled in the light pipe opening 134 to form a light pipe 138 on each photosensitive element 102. The cross-sectional pattern of the light pipe 138 in this embodiment is upper width and lower narrow, but it is not limited thereto. The refractive index of the material of the light pipe 138 is preferably lower than that of the material of the barrier layer 136. The material of the light pipe 138 of this embodiment is a photoresist material or a photoresist-like material, but it is not limited thereto. When forming the light pipe 138, the high-refractive index material may be first filled and exceeded the light pipe opening 134, and then the high-refractive index material outside the light pipe opening 134 may be removed by a chemical mechanical polishing process, but it is not limited thereto.

As shown in FIG. 7, a plurality of different color filter layers 140 are formed on the upper dielectric layer 128 to cover the corresponding photosensitive elements 102 and light pipes 138 respectively. The color filter layer 140 may include, for example, a colored photoresist pattern, and may be manufactured by a lithography process, but is not limited thereto. The color of the color filter layer 140 may include red, blue, or green, so that the photosensitive element 102 can sense light of a specific color. Then, a micro-condensing mirror 142 is formed on each color filter layer 140, and covers the photosensitive element 102 and the light pipe 138 under it.

In summary, the method for manufacturing the image sensor 1A of the present invention mainly includes the steps shown in FIG. 8:

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

Step S12: forming a patterned conductive layer on the substrate, wherein the patterned conductive layer includes at least one interconnect and is electrically connected to the photosensitive element;

Step S14: forming a dielectric layer on the patterned conductive layer to cover the patterned conductive layer in steps;

Step S16: forming an optical barrier layer on the substrate, and stepwise covering the lower dielectric layer; and

Step S18: forming an upper dielectric layer on the substrate to cover the optical barrier layer, wherein the refractive index of the optical barrier layer is greater than that of the upper dielectric layer and the lower dielectric layer.

Please continue to refer to FIG. 7. The image sensor 1A of this embodiment includes a substrate 100, a plurality of photosensitive elements 102, at least one patterned conductive layer, at least a lower dielectric layer 118, an optical barrier layer 120, and at least one upper dielectric. Electrical layer 128. The photosensitive element 102 is disposed on the surface of the substrate 100, the patterned conductive layer is disposed on the substrate 100, and the patterned conductive layer includes at least one interconnect 112 and is disposed on one side of the photosensitive element 102. The interconnecting line 112 in this embodiment has a trapezoidal cross-sectional pattern. It should be noted that the image sensor 1A of this embodiment includes a plurality of patterned conductive layers and a plurality of interlayer dielectric layers 114, and each of the patterned conductive layers is covered with a layer of the interlayer dielectric layer 114. The interconnects 112 of each patterned conductive layer can be connected in series through the contact holes 116 in the interlayer dielectric layer 114 to form a multilayer interconnect structure. In the image sensor 1A of this embodiment, the uppermost interlayer dielectric layer 114 includes an upper dielectric layer 128 and a lower dielectric layer 118, and the optical barrier layer 120 and the lower dielectric layer 118 cover the interconnects 112 in steps. That is, the optical barrier layer 120 and the lower dielectric layer 118 fluctuate with the covered interconnects 112, that is, the interface between the optical barrier layer 120 and the lower dielectric layer 118 will follow the covered interconnects. The line 112 is undulating and includes a plurality of side portions 124 and a plurality of flat portions 126. In addition, since the interconnect line 112 in this embodiment has a trapezoidal cross-sectional pattern, the side portions 124 are inclined surfaces, respectively, and the angle α between the side portions 124 and the surface of the substrate 100 is less than 90 degrees. In addition, the refractive index of the optical barrier layer 120 is larger than that of the upper dielectric layer 128 and the lower dielectric layer 118. In addition, the image sensor 1A may further include a reset transistor, a source follower transistor, or a read select transistor, and may include a triode (3T) Pixel circuit with four transistors (4T). In order to highlight the features of the image sensor 1A of this embodiment, the above components are not shown in the drawings. For other components and materials of the first embodiment of the image sensor 1A of the present invention, reference may be made to the description of the foregoing process, and details are not described again.

Please refer to FIG. 9 and FIG. 10, where FIG. 9 is a schematic view of a light path of the first embodiment of the image sensor of the present invention, and FIG. 10 is a partially enlarged schematic view of an area X in FIG. 9. In the following, light rays L1, L2, and L3 will be used to explain how the optical barrier layer 120 of this embodiment achieves the effect of reducing cross-talk. For the detailed travel path of the light ray L1, please refer to FIG. 10. First, the light ray L1 is incident from the upper dielectric layer 128 to the optical barrier layer 120 through the right color filter layer 140, and enters the optical barrier layer 120 and the upper dielectric layer 128. The interface 144 is refracted. Since the refractive index of the upper dielectric layer 128 is smaller than that of the optical barrier layer 120, according to Snell's law, the light L1 will continue to travel in the optical barrier layer 120 to a lower angle with a larger refraction angle. The interface side portion 124 between the dielectric layers 118 has an incident angle θ. Since the material of the dielectric layer 118 in this embodiment is silicon dioxide (refractive index is 1.45), and the material of the optical barrier layer 120 is silicon nitride (refractive index is 1.99), when the light L1 is on the optical barrier layer 120 Total reflection occurs when the incident angle θ of the side portion 124 is greater than 46 degrees, thereby causing the light L1 to reflect to the right and advance toward the corresponding photosensitive element 102 below to prevent the light L1 from following the original The incident direction advances toward the photosensitive element 102 adjacent to the left.

Please continue to refer to FIG. 9. The incident angle of the light L2 in FIG. 9 is relatively large. After passing through the color filter layer 140, it is incident on the optical barrier layer 120 and the lower dielectric layer 118 interface toward the adjacent photosensitive element 102 on the left. The flat portion 126, however, as long as the incident angle of the light L2 is greater than the critical angle of total reflection, the light L2 can go through the total reflection in a direction opposite to the photosensitive element 102, thereby avoiding the light L2 toward the adjacent photosensitive element on the left 102 forward. On the other hand, the light L3 enters the light pipe 138 after passing through the color filter layer 140, and although it advances toward the photosensitive element 102 adjacent to the left side, it enters between the barrier layer 136 and the interlayer dielectric layer 114. At the interface, since the material of the barrier layer 136 is silicon nitride and the material of the interlayer dielectric layer 114 is silicon dioxide, the incident angle of the light L3 is easily larger than the critical angle of total reflection, and is reflected to the corresponding angle through total reflection. The direction of the photosensitive element 102 is advanced, thereby avoiding the light L3 from advancing toward the photosensitive element 102 adjacent to the left side.

It can be known from the foregoing that the lower dielectric layer 118, the optical barrier layer 120, and the upper dielectric layer 128 are sequentially arranged on the interconnect 112 of the topmost layer of the image sensor 1A of the present invention, and the optical barrier layer is selected through the selection of materials. The refractive index of 120 is greater than the refractive index of the lower dielectric layer 118 and the upper dielectric layer 128, so light may easily cause total reflection when traveling to the interface between the optical barrier layer 120 and the lower dielectric layer 118. In addition, the optical barrier layer 120 and the lower dielectric layer 118 cover the interconnects 112 in a stepped manner, so that the interface between the optical barrier layer 120 and the lower dielectric layer 118 has a side portion 124 and a flat portion 126, further making more different incidence directions. The light can be totally reflected. Therefore, under the design of the present invention, it is possible to effectively prevent light that originally did not go toward the corresponding photosensitive element 102 from passing through the area of the interconnect 112 to be incident on the adjacent photosensitive element 102 and absorbed, thereby effectively improving the image sensor. 1A cross interference problem.

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. 11, which is a schematic cross-sectional view of a modified embodiment of the first embodiment of the image sensor of the present invention. As shown in FIG. 11, this modified embodiment is different from the first embodiment in that the cross-sectional pattern of the interconnecting line 112 is rectangular, and the sidewall of the interconnecting line 112 is substantially perpendicular to the surface of the substrate 100. Since the interface between the optical barrier layer 120 and the lower dielectric layer 118 fluctuates with the lower interconnect line 112, the side portion 124 of the interface of the image sensor 1B is substantially perpendicular to the surface of the substrate 100.

Please refer to FIG. 12 and FIG. 13, which are process schematic diagrams of a manufacturing method of the second embodiment of the image sensor of the present invention, and FIG. 13 shows a schematic sectional view of the image sensor of the second embodiment of the present invention Among them, in the second embodiment, FIG. 12 is a process following FIG. 1. As shown in FIG. 12, this embodiment is different from the first embodiment in that, after the first interconnect 112 is formed on the insulating layer 106, the lower dielectric layer 118 is formed on the interconnect 112 first. The ladder covers the interconnector 112. Next, an optical barrier layer 120 is formed on the lower dielectric layer 118, and the lower dielectric layer 118 is also covered stepwise, and then an upper dielectric layer 128 having a flat surface is formed on the optical barrier layer 120 to cover the optical barrier layer 120 and the lower dielectric layer. The electrical layer 118, wherein the refractive index of the optical barrier layer 120 is greater than the refractive indices of the upper dielectric layer 128 and the lower dielectric layer 118.

As shown in FIG. 13, a plurality of contact holes 116 are formed in the upper dielectric layer 128, the lower dielectric layer 118, and the optical barrier layer 120, and then another layer of interconnects 112 is formed on the upper dielectric layer 128, and Each contact hole 116 is electrically connected to the lower interconnect line 112. Then, the above-mentioned process of forming the upper dielectric layer 128, the optical barrier layer 120, and the lower dielectric layer 118 and the process of forming the contact hole 116 and the interconnect 112 can be repeated. In addition, the interconnects 112 of each of the patterned conductive layers can be connected in series through the upper dielectric layer 128, the lower dielectric layer 118, and the contact holes 116 in the optical barrier layer 120 to form a multilayer interconnect structure. Furthermore, the upper dielectric layer 128 and the lower dielectric layer 118 between the upper and lower interconnects 112 can be collectively regarded as the interlayer dielectric layer 114 in the first embodiment. In other words, the image sensor of this embodiment 2A includes a plurality of interlayer dielectric layers 114, wherein each of the interlayer dielectric layers 114 has an optical barrier layer 120 therein. After the upper dielectric layer 128 is fabricated, the light guide 134, the color filter layer 140, and the micro-condenser 142 can be fabricated. The positions, materials, and manufacturing methods of the remaining components in the image sensor 2A can refer to the first implementation. Example, so I wo n’t repeat them.

Please refer to FIG. 14, which is a schematic cross-sectional view of a modified embodiment of the second embodiment of the image sensor of the present invention. As shown in FIG. 14, this modified embodiment differs from the second embodiment in that the cross-sectional pattern of the interconnector 112 is rectangular, and the sidewalls of the interconnector 112 are substantially perpendicular to the surface of the substrate 100. Since the interface between the optical barrier layer 120 and the lower dielectric layer 118 fluctuates with the lower interconnect line 112, the side portion 124 of the interface of the image sensor 2B is substantially perpendicular to the surface of the substrate 100.

In summary, the present invention provides at least one optical barrier layer on the photosensitive element of the image sensor, wherein the optical barrier layer is disposed between the upper dielectric layer and the lower dielectric layer of the interlayer dielectric layer, and passes through the material. The refractive index of the optical barrier layer is selected to be greater than the refractive index of the lower dielectric layer and the upper dielectric layer, so as to provide a condition that incident light is more likely to have total reflection. In addition, the optical barrier layer and the lower dielectric layer cover the interconnects in a stepped manner, so that the interface between the optical barrier layer and the lower dielectric layer has a side portion and a flat portion, further allowing more light in different incident directions to be totally reflected. In this way, the light that does not originally go toward the corresponding photosensitive element is absorbed by the adjacent photosensitive element, and even the deflected light is reflected back to the corresponding photosensitive element, thereby improving the problem of cross-interference of the image sensor, and At the same time, it improves the sensitivity. 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.

1A, 1B, 2A, 2B‧‧‧Image Sensor

100‧‧‧ substrate

102‧‧‧photosensitive element

106‧‧‧ Insulation

112‧‧‧Internal connection

114‧‧‧ Interlayer dielectric layer

116‧‧‧Contact hole

118‧‧‧ lower dielectric layer

120‧‧‧ Optical barrier layer

144‧‧‧Interface

124‧‧‧Side section

126‧‧‧ flat

128‧‧‧ upper dielectric layer

130‧‧‧ patterned mask layer

132‧‧‧etching process

134‧‧‧light pipe opening

136‧‧‧Barrier layer

138‧‧‧light pipe

140‧‧‧color filter

142‧‧‧Micro Condenser

144‧‧‧Isolated structure

1, L2, L3‧‧‧‧light

α‧‧‧ Angle

θ‧‧‧ incident angle

FIG. 1 to FIG. 7 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. 8 is a flowchart of the manufacturing process steps of the first embodiment of the image sensor manufacturing method of the present invention. FIG. 9 is a schematic diagram of a light path of a first embodiment of an image sensor of the present invention. FIG. 10 is a partially enlarged schematic diagram of the region X in FIG. 9. FIG. 11 is a schematic cross-sectional view of a first modified embodiment of the first embodiment of the image sensor of the present invention. FIG. 12 to FIG. 13 are schematic diagrams illustrating a manufacturing process of a manufacturing method of a second embodiment of the image sensor of the present invention. FIG. 14 is a schematic cross-sectional view of a modified embodiment of the second embodiment of the image sensor of the present invention.

1A‧‧‧Image Sensor

100‧‧‧ substrate

102‧‧‧photosensitive element

106‧‧‧ Insulation

112‧‧‧Internal connection

114‧‧‧ Interlayer dielectric layer

116‧‧‧Contact hole

118‧‧‧ lower dielectric layer

120‧‧‧ Optical barrier layer

124‧‧‧Side section

126‧‧‧ flat

128‧‧‧ upper dielectric layer

134‧‧‧light pipe opening

136‧‧‧Barrier layer

138‧‧‧light pipe

140‧‧‧color filter

142‧‧‧Micro Condenser

144‧‧‧Isolated structure

Claims (19)

An image sensor includes: a photosensitive element disposed on a substrate surface; at least one patterned conductive layer disposed on the substrate; the patterned conductive layer includes at least one interconnect disposed on the photosensitive One side of the element; at least a lower dielectric layer is disposed on the substrate and covers the interconnect; at least one optical barrier layer covers the lower dielectric layer, and the optical barrier layer and the lower dielectric layer are completely stepped Covering the interconnect; and at least one upper dielectric layer covering the optical barrier layer, wherein a refractive index of the optical barrier layer is greater than a refractive index of the upper dielectric layer and the lower dielectric layer. The image sensor according to claim 1, wherein the optical barrier layer and the lower dielectric layer cover the interconnector in steps, and there is an interface between the optical barrier layer and the lower dielectric layer, and the interface follows It fluctuates between the lower dielectric layer and the interconnection line covered by the optical barrier layer and includes a plurality of side portions and a plurality of flat portions. The image sensor of claim 2, wherein the side portions are substantially perpendicular to a surface of the substrate. The image sensor according to claim 2, wherein the side portions are respectively inclined surfaces and have an included angle with the surface of the substrate of less than 90 degrees. The image sensor according to claim 1, comprising a plurality of patterned conductive layers sequentially disposed on the substrate, each of the patterned conductive layers includes at least one interconnect, and the optical barrier layer covers Cover the top interconnector. The image sensor according to claim 1, comprising a plurality of patterned conductive layers sequentially disposed on the substrate, and a surface of each of the patterned conductive layers is provided with the lower dielectric in order from bottom to top. Layer, the optical barrier layer and the upper dielectric layer, so that each of the optical barrier layers respectively covers the interconnections of the patterned conductive layers of the layer. The image sensor according to claim 1, further comprising: a color filter layer disposed on the upper dielectric layer and covering the photosensitive element; and a micro condenser lens disposed on the color filter layer, And cover the photosensitive element. The image sensor according to claim 1, further comprising a light pipe disposed on the photosensitive element and located in the lower dielectric layer, the optical barrier layer and the upper dielectric layer. The image sensor according to claim 1, wherein the materials of the upper dielectric layer and the lower dielectric layer include silicon dioxide, respectively. The image sensor according to claim 1, wherein the material of the optical barrier layer includes silicon nitride, silicon carbide, aluminum, silicon, or tungsten. A method for manufacturing an image sensor includes: providing a substrate and forming a photosensitive element on the surface of the substrate; and forming a patterned conductive layer on the substrate, the patterned conductive layer including at least one interconnect line and disposed on the substrate. One side of the photosensitive element; Forming a lower dielectric layer on the patterned conductive layer to completely cover the patterned conductive layer stepwise; forming an optical barrier layer on the substrate to completely stepwise cover the lower dielectric layer and the patterned conductive layer; and An upper dielectric layer is formed on the substrate to cover the optical barrier layer, wherein a refractive index of the optical barrier layer is greater than a refractive index of the upper dielectric layer and the lower dielectric layer. The method for manufacturing an image sensor according to claim 11, wherein the method includes forming a plurality of patterned conductive layers on the substrate, and the optical barrier layer covers the patterned conductive layer in the uppermost step. The method for manufacturing an image sensor according to claim 11, wherein the method includes forming a plurality of patterned conductive layers on the substrate, and sequentially forming a dielectric layer on the surface of each of the patterned conductive layers. , An optical barrier layer and an upper dielectric layer, each optical barrier layer covering each of the patterned conductive layers in steps. The method for manufacturing an image sensor according to claim 11, wherein an interface exists between the optical barrier layer and the lower dielectric layer, and the interface follows the area covered by the lower dielectric layer and the optical barrier layer. The patterned conductive layer is undulating and includes a plurality of side portions and a plurality of flat portions. The method for manufacturing an image sensor according to claim 11, further comprising: removing a part of the upper dielectric layer, the lower dielectric layer and the optical barrier layer to form a light pipe opening on the photosensitive element; A high refractive index material is filled into the light pipe opening to form a light pipe on the photosensitive element. The method for manufacturing an image sensor according to claim 15, further comprising forming a barrier layer in the light pipe opening before filling the high refractive index material. The method for manufacturing an image sensor according to claim 11, further comprising: forming a color filter layer on the upper dielectric layer and covering the photosensitive element; and forming a micro condenser lens on the color filter layer. And cover the photosensitive element. The method for manufacturing an image sensor according to claim 11, wherein the materials of the upper dielectric layer and the lower dielectric layer include silicon dioxide, respectively. The method for manufacturing an image sensor according to claim 11, wherein the material of the optical barrier layer includes silicon nitride, silicon carbide, aluminum, silicon, or tungsten.