Image sensor

Abstract

To minimize alignment errors that may occur in forming an isolation layer disposed between photodiodes of an image sensor, to prevent saturation of the photodiodes.SOLUTION: An image sensor comprising: a pixel array including a plurality of pixels arranged on an upper surface of a substrate and a pixel isolation layer between the plurality of pixels, each of the plurality of pixels including at least one photodiode and a pixel circuit below the at least one photodiode; and a logic circuit configured to acquire a pixel signal from the plurality of pixels. The pixel array comprises at least one autofocusing pixel. The at least one autofocusing pixel comprises a first photodiode, a second photodiode, a pixel internal isolation layer disposed between the first photodiode and the second photodiode, and a microlens disposed on the first photodiode and the second photodiode. The pixel internal isolation layer includes a first pixel internal isolation layer and a second pixel internal isolation layer separated from each other in a first direction perpendicular to the upper surface of the substrate. A material of the first pixel internal isolation layer is different from a material of the second pixel internal isolation layer.SELECTED DRAWING: Figure 7

Description

【Technical Field】 【0001】 The present invention relates to an image sensor, and more particularly to an image sensor capable of preventing saturation of photodiodes. 【Background Art】 【0002】 An image sensor is a semiconductor-based sensor that receives light and generates an electrical signal, and includes a pixel array having a plurality of pixels, a logic circuit that drives the pixel array to generate an image, and the like. The logic circuit can acquire pixel signals from pixels to generate image data. 【0003】 In recent years, in image sensors, the development of a new autofocus function for focusing on a subject has been an issue. As an autofocus function of an image sensor, an autofocus pixel including a first photodiode and a second photodiode separated by an intra-pixel isolation film has been developed. In this case, problems such as alignment errors may occur in the isolation film disposed between the photodiodes. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Laid-Open No. 01-013878 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 The present invention has been made in view of the problems in the above-described conventional image sensors, and an object of the present invention is to minimize alignment errors that may occur in the process of forming an isolation film disposed between photodiodes and to provide an image sensor capable of preventing saturation of photodiodes. 【Means for Solving the Problems】 【0006】 To achieve the above objective, the present invention provides an image sensor comprising: a plurality of pixels arranged along one direction parallel to the upper surface of a substrate; and a pixel isolation film disposed between the plurality of pixels, wherein each of the plurality of pixels has a pixel array comprising at least one photodiode and a pixel circuit below the at least one photodiode; and a logic circuit for acquiring pixel signals from the plurality of pixels, wherein the pixel array comprises at least one autofocus pixel, the autofocus pixel comprising a first photodiode, a second photodiode, a pixel internal isolation film disposed between the first photodiode and the second photodiode, and a microlens disposed above the first photodiode and the second photodiode, wherein the pixel internal isolation film comprises a first pixel internal isolation film and a second pixel internal isolation film separated from each other in a first direction perpendicular to the upper surface of the substrate, and the first pixel internal isolation film and the second pixel internal isolation film comprise different materials. Furthermore, in a plane parallel to the upper surface of the substrate, the first pixel internal isolation film extends in a second direction, and the second pixel internal isolation film extends in a third direction different from the second direction. It is characterized by the following: 【0007】 Furthermore, an image sensor according to the present invention made to achieve the above objective includes a substrate having a first surface and a second surface facing the first surface, a plurality of pixels, and a pixel separation film disposed between the plurality of pixels and extending from the first surface to the second surface along a first direction perpendicular to the first surface, wherein each of the plurality of pixels includes a pixel array including a pixel circuit having at least one photodiode disposed inside the substrate and a plurality of elements disposed on the first surface, and a logic circuit for acquiring pixel signals from the plurality of pixels, and the pixel array The device includes at least one autofocus pixel, the autofocus pixel includes a first photodiode, a second photodiode, a pixel internal isolation film extending from a first plane along a first direction between the first and second photodiodes, and a microlens disposed on the second plane, the pixel internal isolation film includes a first pixel internal isolation film extending from the first plane and a second pixel internal isolation film extending from the second plane, the first and second pixel internal isolation films having different shapes in a plane parallel to the first plane Furthermore, in a plane parallel to the first surface, the first pixel internal separation membrane extends in a second direction, and the second pixel internal separation membrane extends in a third direction different from the second direction. It is characterized by the following: [Effects of the Invention] 【0009】 The image sensor according to the present invention includes an autofocus pixel, the autofocus pixel may include a first photodiode and a second photodiode separated by an internal pixel isolation film, the internal pixel isolation film includes a first internal pixel isolation film and a second internal pixel isolation film formed of different materials from each other, the internal pixel isolation film extends from a first surface of the substrate together with the pixel isolation films between the pixels, and can provide a charge path through which charge can move between the first photodiode and the second photodiode. Therefore, the alignment error between the pixel separator and the internal pixel separator can be minimized, improving the pixel capacitance. [Brief explanation of the drawing] 【0010】 [Figure 1] This is a block diagram showing a schematic configuration of an image sensor according to one embodiment of the present invention. [Figure 2] This figure shows a schematic configuration of the pixel array of an image sensor according to an embodiment of the present invention. [Figure 3] This figure shows a schematic configuration of the pixel array of an image sensor according to an embodiment of the present invention. [Figure 4] This figure shows a schematic configuration of the pixel array of an image sensor according to an embodiment of the present invention. [Figure 5] This is a schematic diagram showing the general configuration of the pixel circuit of an image sensor according to one embodiment of the present invention. [Figure 6] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 7] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 8] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 9] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 10] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 11] This figure shows a schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. [Figure 12] This figure shows a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 13] This figure shows a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 14] This figure shows a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 15] This figure shows a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 16] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 17] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 18] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 19] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 20] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 21] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 22] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 23] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 24] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 25] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 26] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 27] It is a diagram showing a schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. [Figure 28] It is a diagram for explaining a method of manufacturing an image sensor according to an embodiment of the present invention. [Figure 29] It is a diagram for explaining a method of manufacturing an image sensor according to an embodiment of the present invention. [Figure 30]This figure illustrates a method for manufacturing an image sensor according to an embodiment of the present invention. [Figure 31] This figure illustrates a method for manufacturing an image sensor according to an embodiment of the present invention. [Figure 32] This figure illustrates a method for manufacturing an image sensor according to an embodiment of the present invention. [Figure 33] This figure illustrates a method for manufacturing an image sensor according to an embodiment of the present invention. [Figure 34] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 35] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 36] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 37] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 38] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 39] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 40] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 41] This figure illustrates a method for manufacturing an image sensor according to another embodiment of the present invention. [Figure 42] This is a block diagram showing a schematic configuration of an electronic device including an image sensor according to one embodiment of the present invention. [Figure 43] Figure 42 is a block diagram that schematically shows the configuration of the camera module. [Modes for carrying out the invention] 【0011】 Next, specific examples of embodiments for implementing the image sensor according to the present invention will be described with reference to the drawings. 【0012】 Figure 1 is a block diagram showing a schematic configuration of an image sensor according to one embodiment of the present invention. Referring to Figure 1, the image sensor 1 includes a pixel array 10 and logic circuits 20, etc. 【0013】 The pixel array 10 includes multiple pixels PX arranged in an array configuration along multiple rows and multiple columns. Each of the multiple pixels PX includes at least one photoelectric element that generates an electric charge in response to light, and a pixel circuit that generates a pixel signal corresponding to the charge generated by the photoelectric element. The photoelectric conversion element may include a photodiode formed from a semiconductor material, and / or an organic photodiode formed from an organic material. 【0014】 For example, a pixel circuit may include a floating diffusion transistor, a transmission transistor, a reset transistor, a drive transistor, and a selection transistor. The pixel PX configuration may vary depending on the embodiment. For example, each pixel PX may include an organic photodiode containing an organic material, or it may be implemented as a digital pixel. If the pixel PX is implemented with digital pixels, each pixel PX may include an analog-to-digital converter for outputting a digital pixel signal. 【0015】 The logic circuit 20 includes a circuit for controlling the pixel array 10. For example, the logic circuit 20 includes a low driver 21, a readout circuit 22, a column driver 23, and control logic 24. The row driver 21 drives the pixel array 10 in row-line units. For example, the low driver 21 generates transmission control signals to control the transmission transistors of the pixel circuit, reset control signals to control the reset transistors, and selection control signals to control the selection transistors, and inputs them to the pixel array 10 in low line units. 【0016】 The readout circuit 22 may include a Correlated Double Sampler (CDS), an Analog-to-Digital Converter (ADC), and the like. The correlated dual sampler connects pixel PX and column lines. The correlated dual sampler reads the pixel signal via the column line from the pixel PX connected to the low line selected by the low line selection signal of the low driver 21. The analog-to-digital converter converts the pixel signals detected by the correlated duplex sampler into digital pixel signals and transmits them to the column driver 23. 【0017】 The column driver 23 may include a latch or buffer circuit and an amplifier circuit that can temporarily store the digital pixel signal, and processes the digital pixel signal received from the readout circuit 22. The low driver 21, the readout circuit 22, and the column driver 23 are controlled by the control logic 24. The control logic 24 may include a timing controller for controlling the operating timing of the low driver 21, the readout circuit 22, and the column driver 23. 【0018】 Pixels PX that are located at the same position horizontally share the same column line. For example, pixels PX positioned at the same location in the vertical direction are simultaneously selected by the low driver 21 and output pixel signals via the column line. In one embodiment, the readout circuit 22 simultaneously acquires a pixel signal from a pixel PX selected by the low driver 21 via a column line. The pixel signal may include a reset voltage and a pixel voltage, where the pixel voltage may be a voltage in which the charge generated in response to light from each pixel PX is reflected in the reset voltage. 【0019】 In one embodiment, the pixel array 10 may include at least one autofocus pixel. An autofocus pixel may include two or more photodiodes, and the logic circuit 20 uses the difference between the pixel signals obtained from the photodiodes included in each of the autofocus pixels to realize the autofocus function of the image sensor 1 and / or the camera device including the image sensor 1. To enable accurate calculation of the difference between pixel signals obtained from two or more photodiodes contained within the autofocus pixel, the autofocus pixel includes an internal pixel isolation film for separating the photodiodes. Because the photodiodes are separated from each other by the internal pixel isolation film, the light-receiving area of ​​each photodiode is determined by the position of the internal pixel isolation film. However, if the internal separation films of the pixels are not precisely aligned, resulting in differences in the light-receiving area of ​​each photodiode, the autofocus function of the image sensor 1 may be impaired. 【0020】 In one embodiment of the present invention, the pixel internal isolation film is formed from the first surface of the substrate, similar to the pixel isolation film between pixels PX, in order to minimize the error in the light-receiving area of ​​each photodiode within the autofocus pixel. For example, the first surface is the surface on which the pixel circuits contained within each pixel PX are formed. For example, the internal pixel separation film is formed using the same process as the pixel separation film. Therefore, the placement error of the internal pixel isolation film can be minimized, and the error in the light-receiving area of ​​each photodiode can be reduced, thereby improving the autofocus function of the image sensor 1. Furthermore, even if the area of ​​each pixel PX is reduced in order to increase the resolution of the image sensor 1, the autofocus function of the image sensor 1 can still be effectively realized. 【0021】 Figures 2 to 4 show the schematic configuration of the pixel array of an image sensor according to an embodiment of the present invention. First, referring to Figure 2, the pixel array 100 of the image sensor according to one embodiment of the present invention includes a plurality of pixels (110, 120). 【0022】 For example, the pixel array 100 includes general pixels 110 and autofocus pixels 120. Each of the general pixels 110 and the autofocus pixels 120 may be multiple, and their number may vary in various ways. For example, the number of general pixels 110 may be greater than the number of autofocus pixels 120. Furthermore, the position of the autofocus pixel 120 is not limited to that shown in Figure 2, but can be varied in many ways. 【0023】 The autofocus pixel 120 includes a first photodiode and a second photodiode. In the autofocus pixel 120, the first and second photodiodes are arranged along one direction (lateral direction), and the first and second photodiodes share a single microlens. Depending on the embodiment, in some of the autofocus pixels 120, the first photodiode and the second photodiode may be arranged along directions different from one direction. 【0024】 Referring to Figure 3, the pixel array 100A includes a plurality of pixels 110A, and each of the plurality of pixels 110A includes a first photodiode and a second photodiode. In the embodiment shown in Figure 3, each of the pixels 110A included in the pixel array 100A may be an autofocus pixel. As mentioned above with reference to Figure 2, in at least some of the pixels 110A, the first and second photodiodes can also be arranged in other directions, for example, vertically. However, depending on the embodiment, only a portion of the pixels 110A may be used for the autofocus function. 【0025】 Next, referring to Figure 4, the pixel array 100B includes multiple pixel groups 110B, each of which contains a unit pixel PX. Each unit pixel PX contained within pixel group 110B contains the same color filter. In the embodiment shown in Figure 4, each unit pixel PX includes a first photodiode and a second photodiode. However, depending on the embodiment, only a portion of the unit pixel PX may contain the first photodiode and the second photodiode, or the arrangement direction of the first photodiode and the second photodiode may be different in at least a portion of the unit pixel PX. 【0026】 In the embodiment described with reference to Figures 2 to 4, a pixel internal isolation film is placed between the first photodiode and the second photodiode. For example, the light-receiving area of ​​the first and second photodiodes is determined by the internal isolation film of the pixel. If the internal pixel isolation film is not precisely aligned between the first and second photodiodes, a difference may occur between the light-receiving areas of the first and second photodiodes, potentially degrading the autofocus function of the image sensor. 【0027】 In one embodiment of the present invention, the above-mentioned problems can be solved by forming an internal pixel separation film along with a pixel separation film that separates pixels from each other. For example, trenches for forming a pixel separation film and trenches for forming an internal pixel separation film are formed simultaneously in a single process. Therefore, by precisely aligning the internal pixel isolation film and minimizing the difference in light-receiving area between the first and second photodiodes, it is possible to prevent a decrease in the autofocus function of the image sensor. 【0028】 Figure 5 is a schematic diagram showing the general configuration of the pixel circuit of an image sensor according to one embodiment of the present invention. As an example, Figure 5 is a circuit diagram showing a pixel circuit that includes a first photodiode and a second photodiode separated from each other by an internal pixel isolation film, and which can provide an autofocus function. However, the pixel circuit for the pixels that provide the autofocus function is not necessarily limited to that shown in Figure 5, and some elements may be added or omitted as needed. 【0029】 Referring to Figure 5, the pixel circuit is connected to the first photodiode PD1 and the second photodiode PD2, and outputs a reset voltage and a pixel voltage to the column line COL. As an example, the pixel circuit may include a first transmission transistor TX1, a second transmission transistor TX2, a reset transistor RX, a drive transistor SF, a selection transistor SX, and a conversion gain transistor DCX. The pixel circuit is connected to the image sensor's logic circuit via the column line COL, and the logic circuit obtains the reset voltage and pixel voltage via the column line COL to generate the pixel signal. 【0030】 During the exposure time, the first photodiode PD1 and the second photodiode PD2 are exposed to light and generate charge, which sequentially turns on the first transmission transistor TX1 and the second transmission transistor TX2. The logic circuit provides an autofocus function using a first pixel signal acquired after the first transmission transistor TX1 is turned on, and a second pixel signal acquired after the second transmission transistor TX2 is turned on. 【0031】 Figures 6 to 11 show the schematic configuration of pixels included in an image sensor according to one embodiment of the present invention. Figure 6 shows a schematic configuration of some pixels (PX1 to PX4) included in an image sensor 200 according to one embodiment of the present invention. On the other hand, Figure 7 is a cross-sectional view showing the cross-section in the I-I' direction of Figure 6, and Figure 8 is a cross-sectional view showing the cross-section in the II-II' direction of Figure 6. 【0032】 Referring to Figures 6 to 8, a pixel separation membrane 210 is placed between the pixels (PX1 to PX4), and each of the pixels (PX1 to PX4) contains a pixel internal separation membrane 220. The pixel internal isolation film 220 is placed between the first photodiode PD1 and the second photodiode PD2. The pixel isolation film 210 and the pixel internal isolation film 220 are extended in a first direction (Z-axis direction) within the substrate 201 containing the semiconductor material. 【0033】 A pixel circuit is positioned below the first photodiode PD1 and the second photodiode PD2. As an example, a pixel circuit includes a plurality of elements 230, a wiring pattern 231 connected to the plurality of elements 230, and an insulating layer 232 covering the plurality of elements 230 and the wiring pattern 231, and is arranged on the first surface of a substrate 201. The pixel circuit includes floating diffusion (FD1, FD2). For example, each pixel (PX1~PX4) includes a first floating diffusion FD1 and a second floating diffusion FD2. The first floating diffusion FD1 is located below the first photodiode PD1. The second floating diffusion diode FD2 is located below the second photodiode PD2. The first floating diffusion FD1 and the second floating diffusion FD2 are electrically connected to each other by at least one of the wiring patterns 231, and the positions and areas of the first floating diffusion FD1 and the second floating diffusion FD2 can be varied in various ways depending on the embodiment. 【0034】 The first floating diffusion FD1 and the second floating diffusion FD2 are arranged on both sides of the pixel internal isolation film 220, and the elements 230 adjacent to the first floating diffusion FD1 and the second floating diffusion FD2 may be the first transmission transistor and the second transmission transistor. The gates of the first and second transmission transistors each have a vertical structure in which at least a portion of the region is embedded in the substrate 201. Each pixel (PX1 to PX4) includes a color filter (202, 203), a light transmission layer 204, and a microlens 205, which are located on the second surface of the substrate 201. For example, each pixel (PX1 to PX4) includes a microlens 205 positioned above the first photodiode PD1 and the second photodiode PD2. Therefore, light that has passed through one microlens 205 can be incident on the first photodiode PD1 and the second photodiode PD2. 【0035】 Referring to Figure 6, the pixel separation membrane 210 has a first width W1, and the pixel internal separation membrane 220 has a second width W2 that is smaller than the first width W1. For example, by making the pixel internal separation membrane 220 narrower than the pixel separation membrane 210, the pixel separation membrane 210 and the pixel internal separation membrane 220 can be formed simultaneously in a single process. However, depending on the embodiment, the pixel separation film 210 and the pixel internal separation film 220 may be formed to have the same width as each other. Furthermore, referring to Figures 7 and 8, in the first direction, the pixel separation membrane 210 has a first length d1, and the pixel internal separation membrane 220 has a second length d2, with the first length d1 being longer than the second length d2. For example, the pixel separation film 210 completely penetrates the substrate 201 and extends from the first surface to the second surface of the substrate 201. 【0036】 In one embodiment, the pixel internal isolation film 220 has a length smaller than the first photodiode PD1 and the second photodiode PD2 in the first direction. Charge moves between the first photodiode PD1 and the second photodiode PD2 with the pixel internal isolation film 220 in between. Therefore, when light is concentrated on the first photodiode PD1 or the second photodiode PD2, the excess charge generated can be moved, thereby preventing saturation of the photodiodes (PD1, PD2). 【0037】 On the other hand, in the embodiments shown in Figures 6 to 8, the pixel separation film 210 and the pixel internal separation film 220 are formed in the same process, and both the pixel separation film 210 and the pixel internal separation film 220 extend from the first surface of the substrate 201 on which the pixel circuit is arranged. By forming the pixel separation film 210 and the internal pixel separation film 220 in the same process, the positions of the pixel separation films 210 can be precisely aligned inside each pixel (PX1 to PX4), minimizing the difference in light-receiving area between the first photodiode PD1 and the second photodiode PD2, thereby improving the autofocus function of the image sensor 200. 【0038】 Next, referring to Figure 9, in each of the pixels (PX1 to PX4), the pixel internal separation membrane 220 includes a first pixel internal separation membrane 221 and a second pixel internal separation membrane 222. The first pixel internal isolation film 221 extends from the first surface of the substrate 201 on which the pixel circuit is arranged, and the second pixel internal isolation film 222 extends from the second surface of the substrate 201 on which the color filters (202, 203), the light transmission layer 204, and the microlens 205 are arranged. In the first direction, the length of the first pixel internal separation membrane 221 is longer than the length of the second pixel internal separation membrane 222. 【0039】 In one embodiment, the first pixel internal separation membrane 221 is formed of a first material, and the second pixel internal separation membrane 222 can be formed of a second material different from the first material. For example, the second material may have a higher reflectivity than the first material. In one embodiment, the first pixel internal separation film 221 may be made of a conductive material, and the second pixel internal separation film 222 may be made of an insulating material. For example, the first pixel internal separation membrane 221 can be made of polysilicon, and the second pixel internal separation membrane 222 can be made of silicon oxide. 【0040】 By forming the second pixel internal separation film 222 with a material having a relatively high reflectivity, light that has passed through the microlens 205 is reflected from the second pixel internal separation film 222 and incident on the first photodiode PD1 or the second photodiode PD2. Therefore, the sensitivity of the image sensor 200A can be improved. Furthermore, by forming the first pixel internal isolation film 221 with a conductive material and applying a predetermined bias voltage, for example, a negative voltage, the dark current generated in the pixels (PX1 to PX4) can be reduced. 【0041】 An impurity region 240 may be placed between the first pixel internal separation membrane 221 and the second pixel internal separation membrane 222. For example, the impurity region 240 could be a region doped with a P-type impurity. The impurity region 240 between the first pixel internal separation film 221 and the second pixel internal separation film 222 provides an efficient charge transfer path between the first photodiode PD1 and the second photodiode PD2. Depending on the embodiment, the impurity region 240 may also be doped with N-type impurities. Depending on the embodiment, as shown in Figure 10, it is also possible to place only the impurity region 240 between the pixel internal separation film 220 and the color filters (202, 203) without the second pixel internal separation film 222. 【0042】 In one embodiment, the impurity region 240 can be formed in the process of forming the first pixel internal separation film 221. As an example, to form the first pixel internal separation film 221, a trench is formed extending from the first surface of the substrate 201, and impurities are injected through the inside of the trench to form an impurity region 240. By first forming a trench for creating the first pixel internal separation membrane 221 and then injecting impurities, the alignment error between the impurity region 240 and the pixel internal separation membrane 220 can be reduced, and the impurity injection process can be performed at a lower energy level. The impurity injection process may cause at least a portion of the impurity region 240 to overlap with the second pixel internal separation film 222. 【0043】 Next, referring to Figure 11, in each of the pixels (PX1 to PX4), the pixel internal separation membrane 220 includes a first pixel internal separation membrane 221 and a second pixel internal separation membrane 222, and an impurity region 240 is formed between the first pixel internal separation membrane 221 and the second pixel internal separation membrane 222. The first pixel internal separation membrane 221, the second pixel internal separation membrane 222, and the impurity region 240 can be understood by referring to the above-mentioned explanation with reference to Figures 9 and 10. 【0044】 In the embodiment shown in Figure 11, the pixel separation membrane 210 includes a first pixel separation membrane 211 and a second pixel separation membrane 212. In the first direction, the length of the first pixel separation membrane 211 is longer than the length of the second pixel separation membrane 212. Furthermore, the second pixel separation film 212 is formed of a material having a higher reflectivity than the first pixel separation film 211. In one embodiment, the first pixel separation membrane 211 is formed of the same material as the first pixel internal separation membrane 221, and the second pixel separation membrane 212 is formed of the same material as the second pixel internal separation membrane 222. 【0045】 By forming the second pixel separation film 212 with a material having high reflectivity, a portion of the light that has passed through the microlens 205 is reflected from the second pixel separation film 212 and then incident on the first photodiode PD1 or the second photodiode PD2. To reduce the amount of light absorbed by the first pixel separation film 211, the second pixel separation film 212 is formed to be longer than the second pixel internal separation film 222 in the first direction. Referring to Figure 11, in the first direction, the length of the first pixel separation membrane 211 is shorter than the length of the first internal pixel separation membrane 221, and the length of the second pixel separation membrane 212 is longer than the length of the second internal pixel separation membrane 222. 【0046】 Figures 12 to 15 show the schematic configuration of pixels included in an image sensor according to another embodiment of the present invention. Figure 12 is a plan view showing some pixels (PX1 to PX4) included in an image sensor 300 according to another embodiment of the present invention, and Figure 13 is a cross-sectional view showing a cross section in the III-III' direction of Figure 12. Figures 14 and 15 are cross-sectional views showing the cross-section in the IV-IV' direction of Figure 12. 【0047】 First, referring to both Figures 12 and 13, the image sensor 300 according to another embodiment of the present invention includes a plurality of pixels (PX1 to PX4). A pixel isolation film 310 is placed between multiple pixels (PX1 to PX4), and each pixel (PX1 to PX4) includes a first photodiode PD1 and a second photodiode PD2 that are separated from each other by a pixel internal isolation film 320. The pixel separation membrane 310 and the pixel internal separation membrane 320 are extended along the first direction (Z-axis direction). 【0048】 In the embodiment described with reference to Figures 12 to 15, the pixel internal separation membrane 320 has a first vertical surface VS1 and a second vertical surface VS2. The first vertical plane VS1 and the second vertical plane VS2 are opposite each other in a third direction (Y-axis direction) that intersects with the second direction (X-axis direction) in which the first photodiode PD1 and the second photodiode PD2 are arranged. Referring to Figure 12, the second vertical plane VS2 is in direct contact with the pixel separation film 310, while the first vertical plane VS1 is separated from the pixel separation film 310. 【0049】 In one embodiment, a floating diffusion FD is placed between the first vertical plane VS1 and the pixel separation film 310. Therefore, in each pixel (PX1 to PX4), the first photodiode PD1 and the second photodiode PD2 share a floating diffusion FD. Furthermore, since excess charge generated in at least one of the first photodiode PD1 and the second photodiode PD2 can move through the space between the first vertical plane VS1 and the pixel isolation film 310, the pixel internal isolation film 320 can completely penetrate the substrate 301, as shown in Figures 13 and 15. For example, the pixel internal isolation film 320 extends from the first surface of the substrate 301 on which the pixel circuits are arranged to the second surface of the substrate 301 on which the color filters (302, 303), light transmission layer 304, and microlens 305 are arranged. 【0050】 On the other hand, referring to Figure 15, the pixel internal separation membrane 320 includes a first pixel internal separation membrane 321 and a second pixel internal separation membrane 322. The first pixel internal separation film 321 is formed of a first material, and the second pixel internal separation film 322 is formed of a second material different from the first material, the second material having a higher reflectivity than the first material. Therefore, light that passes through the microlens 305 and is incident directly on the pixel internal separation film 320 instead of the first photodiode PD1 and the second photodiode PD2 is reflected by the pixel internal separation film 320 without being absorbed and incident on the first photodiode PD1 or the second photodiode PD2, thereby improving the sensitivity of the image sensor 300A. 【0051】 For example, the first material is polysilicon, and the second material is silicon oxide. Furthermore, while Figure 15 shows that the interface between the first pixel internal separation film 321 and the second pixel internal separation film 322 is located lower than the upper surfaces of the first photodiode PD1 and the second photodiode PD2, it is also possible that the interface between the first pixel internal separation film 321 and the second pixel internal separation film 322 is located higher than the upper surfaces of the first photodiode PD1 and the second photodiode PD2. 【0052】 For example, in each of the pixels (PX1 to PX4), the second pixel internal separation film 322 can come into contact with the pixel separation film 310 in a third direction. In other words, in the third direction, the second pixel internal separation membrane 322 can be connected to the pixel separation membrane 310 on both sides. In this case, in the third direction, the first pixel internal separation membrane 321 has a shorter length than the second pixel internal separation membrane 322. 【0053】 Figures 16 and 17 show a schematic configuration of pixels included in an image sensor according to yet another embodiment of the present invention. In yet another embodiment shown in Figures 16 and 17, the image sensor (400, 400A) includes a plurality of pixels (PX1 to PX4) separated by a pixel separation film 410, each of the plurality of pixels (PX1 to PX4) includes a pixel internal separation film 420, a first photodiode PD1, and a second photodiode PD2. 【0054】 First, referring to Figure 16, the pixel internal separation membrane 420 includes a first vertical surface VS1 and a second vertical surface VS2, one of which is in direct contact with the pixel separation membrane 410, and the other is separated from the pixel separation membrane 410. Furthermore, in one embodiment shown in Figure 16, adjacent pixels in the third direction (Y-axis direction), for example, the first pixel PX1 and the third pixel PX3, have a structure in which they are vertically symmetrical to each other. 【0055】 In the embodiment shown in Figure 17, both the first vertical plane VS1 and the second vertical plane VS2 of the pixel internal separation membrane 420A are separated from the pixel separation membrane 410. Referring to Figure 17, in the third direction (Y-axis direction), the first floating diffusion FD1 is positioned between the first vertical plane VS1 and the pixel separation film 410, and the second floating diffusion FD2 is positioned between the second vertical plane VS2 and the pixel separation film 410. The first floating diffusion FD1 and the second floating diffusion FD2 are electrically connected to each other by wiring patterns or the like. Depending on the embodiment, each pixel (PX1 to PX4) may also be equipped with only one of the first floating diffusion FD1 and the second floating diffusion FD2. 【0056】 In the embodiments shown in Figures 16 and 17, each of the pixel internal separation membranes (420, 420A) includes a first internal separation membrane and a second internal separation membrane. The first internal separation membrane and the second internal separation membrane are either in direct contact with each other or separated, and if the first internal separation membrane and the second internal separation membrane are separated, an impurity region is located between them. Furthermore, the first internal separation membrane and the second internal separation membrane can have different shapes. In one embodiment, the first internal separation membrane and the second internal separation membrane can have different lengths in the third direction. Alternatively, an impurity region can be formed between the first internal separation membrane and the color filter without the second internal membrane. 【0057】 Figures 18 and 19 show schematic configurations of pixels included in an image sensor according to yet another embodiment of the present invention. Figure 18 is a schematic diagram showing some pixels (PX1 to PX4) included in an image sensor 500 according to yet another embodiment of the present invention, and Figure 19 is a cross-sectional view showing the V-V' direction of Figure 18. 【0058】 The pixels (PX1 to PX4) are separated from each other by a pixel isolation film, and in each of the pixels (PX1 to PX4), the first photodiode PD1 and the second photodiode PD2 are separated from each other by an internal pixel isolation film 520. The pixel isolation film 510 and the pixel internal isolation film 520 extend from inside the substrate 501 in the first direction (Z-axis direction). The pixel separation film 510 extends from the first surface to the second surface of the substrate 501. For example, the first surface is where multiple elements 530, wiring patterns 531, and insulating layers 532 are arranged, and the second surface is where color filters (502, 503), light transmission layers 504, and microlenses 505 are arranged. 【0059】 The pixel internal isolation film 520 includes a first pixel internal isolation film 521 and a second pixel internal isolation film 522, and the first pixel internal isolation film 521 and the second pixel internal isolation film 522 intersect each other on the first surface of the substrate 501. The first photodiode PD1 and the second photodiode PD2 are separated from each other by the first pixel internal isolation film 521, and the second pixel internal isolation film 522 does not overlap with the first photodiode PD1 and the second photodiode PD2 in the second direction (X-axis direction) and the third direction (Y-axis direction). 【0060】 Referring to Figure 18, on the first surface, the second pixel internal separation membrane 522 extends in the second direction, and the first pixel internal separation membrane 521 extends in the third direction. Referring to Figure 19, in the first direction, the first pixel internal separation membrane 521 and the second pixel internal separation membrane 522 are separated from each other, and an impurity region 540 is formed between them. Although the first pixel internal isolation film 521 has been shown to have a shorter length than the first photodiode PD1 and the second photodiode PD2 in the first direction, it is not necessarily limited to this configuration. 【0061】 The first pixel internal separation membrane 521 and the second pixel internal separation membrane 522 may be formed from different materials. For example, the first pixel internal separation film 521 is made of a conductive material, and the second pixel internal separation film 522 is made of an insulating material. In one embodiment, the second pixel internal separation film 522 is formed to have a higher reflectivity than the first pixel internal separation film 521. In this case, the light that has passed through the microlens 505 is reflected from the second pixel internal separation film 522 and then incident on the first photodiode PD1 or the second photodiode PD2. On the first surface of the substrate 501, the widths of the first pixel internal separation film 521 and the second pixel internal separation film 522 may be the same as or smaller than the width of the pixel separation film 510. In one embodiment, the widths of the first pixel internal separation membrane 521 and the second pixel internal separation membrane 522 may be the same. 【0062】 Figures 20 to 22 show schematic configurations of pixels included in an image sensor according to yet another embodiment of the present invention. First, referring to Figure 20, the pixels (PX1 to PX4) of the image sensor 600 are separated by a pixel separation membrane 610, and each of the pixels (PX1 to PX4) includes a first pixel internal separation membrane 621 and a second pixel internal separation membrane 622. 【0063】 Similar to the embodiments described above with reference to Figures 18 and 19, the first pixel internal separation membrane 621 and the second pixel internal separation membrane 622 are separated from each other in the first direction (Z-axis direction). Furthermore, the second pixel internal isolation film 622 does not overlap with the first photodiode PD1 and the second photodiode PD2 in the second direction (X-axis direction) and the third direction (Y-axis direction). 【0064】 In the embodiment shown in Figure 20, the second pixel internal separation film 622 is extended diagonally in each of the pixels (PX1 to PX4). Depending on the embodiment, in at least some of the pixels (PX1 to PX4), the second pixel internal separation film 622 is extended in directions different from each other. For example, in the first pixel PX1, the second pixel internal separation membrane 622 is extended in a direction of 45 degrees with respect to the second direction, and in the second pixel PX2, the second pixel internal separation membrane 622 is extended in a direction of 135 degrees with respect to the second direction. 【0065】 As shown in Figure 20, by arranging the second pixel internal isolation film 622 diagonally, the pixel signals acquired from the first photodiode PD1 and the second photodiode PD2 can be used for autofocus functions in different directions. As an example, in the embodiment shown in Figure 20, an autofocus function in the vertical direction can be realized using the pixel signals acquired from the first photodiode PD1 and the second photodiode PD2 of the first pixel PX1, respectively. In the embodiment shown in Figure 20, the second pixel internal separation film 622 is extended diagonally, so that the length of the second pixel internal separation film 622 on a plane parallel to the upper surface of the substrate is longer than the length of the first pixel internal separation film 621. 【0066】 Next, referring to Figure 21, the pixels (PX1 to PX4) of the image sensor 700 are separated by a pixel separation membrane 710, and each of the pixels (PX1 to PX4) includes an internal pixel separation membrane 720 that extends diagonally. Therefore, as shown in Figure 21, the first photodiode PD1 and the second photodiode PD2 have different shapes compared to the image sensors (200, 300, 400, 500, 600) according to the above-described embodiments. Each pixel (PX1 to PX4) includes a first floating diffusion FD1 and a second floating diffusion FD2, which are electrically connected to each other by wiring patterns or the like. Furthermore, depending on the embodiment, the pixel internal separation film 720 can be extended in a diagonal direction different from that shown in Figure 21 in at least some of the pixels (PX1 to PX4). 【0067】 Next, in the embodiment shown in Figure 22, the pixel separation film 810, which is placed between pixels (PX1 to PX4) in the image sensor 800, is separated into multiple regions. Referring to Figure 22, each pixel (PX1 to PX4) is surrounded by a pixel isolation membrane 810 in the second direction (X-axis direction) and the third direction (Y-axis direction), and the pixel internal isolation membrane 820 is connected to a pair of pixel isolation membranes 810 that are separated from each other in the third direction. Therefore, in the embodiment shown in Figure 22, at least a portion of the pixel isolation membrane 810 is separated from the pixel internal isolation membrane 820 without being connected to it. 【0068】 Figures 23 to 26 show schematic configurations of pixels included in an image sensor according to yet another embodiment of the present invention. Referring to Figure 23, the pixels (PX1 to PX4) contained in the image sensor 900 are separated from each other by a pixel separation film 910, and the first photodiode PD1 and the second photodiode PD2 contained in each of the pixels (PX1 to PX4) are separated by an internal pixel separation film 920. 【0069】 The pixel internal isolation film 920 includes a plurality of regions separated by a predetermined interval in a third direction (Y-axis direction) that intersects with the second direction (X-axis direction), which is the direction in which the first photodiode PD1 and the second photodiode PD2 are arranged. Floating diffusion FD is positioned between multiple regions contained within the pixel internal isolation film 920. Referring to Figure 25, which shows a cross-section in the VII-VII' direction of Figure 23, the pixel internal separation film 920 does not necessarily have to be placed on top of the floating diffusion FD. 【0070】 In the embodiment shown in Figure 23, the spacing between multiple regions included in the pixel internal separation film 920 differs from one another in some of the pixels (PX1 to PX4). For example, the spacing between multiple regions contained in the pixel internal separation film 920 of the first pixel PX1 is smaller than the spacing between multiple regions contained in the pixel internal separation film 920 of the second pixel PX2. On the other hand, the spacing between multiple regions contained in the pixel internal separation film 920 of the third pixel PX3 is smaller than the spacing between multiple regions contained in the pixel internal separation film 920 of the first pixel PX1. 【0071】 Referring to Figure 24, which shows a cross-section in the VI-VII' direction of Figure 23, the first pixel PX1 contains a green color filter 902, and the second pixel PX2 contains a red color filter 903. On the other hand, the third pixel, PX3, includes a blue color filter. For example, in a pixel that generates an electric charge in response to light in a short wavelength band, the spacing between multiple regions contained in the pixel internal separation film 920 can be relatively reduced. 【0072】 Referring to Figure 24, the substrate 901 has a first surface on which a plurality of elements 930, a wiring pattern 931, and an insulating layer 932 are arranged, and a second surface facing the first surface, and the pixel separation film 910 extends from the first surface to the second surface. The pixel internal separation film 920 extends from the first surface and has a shorter length than the pixel separation film 910 in the first direction (Z-axis direction). 【0073】 On the other hand, referring to Figure 26, the pixel internal separation film 920 includes a first pixel internal separation film 921 extending from the first surface and a second pixel internal separation film 922 extending from the second surface. However, in each pixel (PX1 to PX4), the pixel internal isolation film 920 includes multiple regions separated along a third direction, so that a charge path is realized in each pixel (PX1 to PX4) through which excess charge generated from one of the photodiodes (PD1, PD2) moves to the other. 【0074】 On the other hand, in the image sensor 900A according to the embodiment shown in Figure 26, the second pixel internal separation membrane 922 is in contact with the pixel separation membrane 910 on both sides in the third direction. In other words, unlike the first pixel internal separation film 921 which has multiple regions separated from each other in a third direction, the second pixel internal separation film 922 has a shape that completely spans each of the pixels (PX1 to PX4). Therefore, in the third direction, the second pixel internal separation membrane 922 has a longer length than the first pixel internal separation membrane 921. 【0075】 Figure 27 shows a schematic configuration of pixels included in an image sensor according to yet another embodiment of the present invention. In the image sensor 1000 according to the embodiment shown in Figure 27, each pixel (PX1 to PX4) internal isolation membrane 1020 includes a first pixel internal isolation membrane 1021 and a second pixel internal isolation membrane 1022. The first pixel internal separation membrane 1021 has a structure similar to the pixel internal separation membrane 920 described with reference to Figures 23 to 26. On the other hand, the second pixel internal separation film 1022 is extended diagonally in each of the pixels (PX1 to PX4). 【0076】 Similar to the embodiments described with reference to the other embodiments mentioned above, for example, the embodiments described with reference to Figures 18 and 19, an impurity region can also be formed between the first pixel internal separation membrane 1021 and the second pixel internal separation membrane 1022 in the first direction (Z-axis direction). The impurity region may be provided as a charge path to facilitate charge transfer between the first photodiode PD1 and the second photodiode PD2. 【0077】 Alternatively, as in the embodiment described with reference to Figure 26, the first pixel internal separation membrane 1021 and the second pixel internal separation membrane 1022 may be in contact with each other in the first direction. In this case, the first pixel internal isolation film 1021 has a length longer than the photodiodes (PD1, PD2) in the first direction. Furthermore, depending on the embodiment, an autofocus function in the vertical direction can be realized using a pixel signal corresponding to the charge of the first photodiode PD1 and a pixel signal corresponding to the charge of the second photodiode PD2. 【0078】 Figures 28 to 33 are diagrams illustrating a method for manufacturing an image sensor according to an embodiment of the present invention. First, referring to Figure 28, the manufacturing method of the image sensor begins by forming a pixel separation film 1110 on the substrate 1101. Referring to both Figure 28 and Figure 29, which shows a cross-section in the VIII-VIII' direction, the pixel separation film 1110 is formed from the first surface 1101A of the substrate 1101. As an example, a trench is formed extending from the first surface 1101A of the substrate 1101, and a material such as polysilicon is embedded inside the trench to form a pixel separation film 1110. 【0079】 Referring to Figures 28 and 29, the pixel separation film 1110 is formed together with the pixel internal separation films 1120, which are located inside each of the pixel regions (PA1 to PA4). The pixel internal separation membrane 1120 is formed to have a smaller width than the pixel separation membrane 1110 and contains the same material as the pixel separation membrane 1110, such as polysilicon. Referring to Figure 31, in the first direction (Z-axis direction), the pixel separation membrane 1110 has a first length d1, and the pixel internal separation membrane 1120 has a second length d2 which is shorter than the first length d1. 【0080】 Next, referring to Figures 30 and 31, a photodiode (PD1, PD2) and a pixel circuit are formed in each of the pixel regions (PA1 to PA4). The photodiodes (PD1, PD2) are formed on both sides of the pixel internal isolation film 1120, and are formed, for example, by an impurity implantation process in which N-type impurities are implanted. The pixel circuit is formed on the first surface 1101A of the substrate 1101 and includes floating diffusions (FD1, FD2), multiple elements 1130, wiring patterns 1131, and the like. An insulating layer 1132 covering the pixel circuit is formed on the first surface 1101A of the substrate 1101. The insulating layer 1132 is formed from silicon oxide, silicon nitride, or the like. The floating diffusions (FD1, FD2) are formed adjacent to the pixel internal isolation film 1120, and the element 1130 adjacent to the floating diffusions (FD1, FD2) may be a transmission transistor. 【0081】 Next, referring to Figure 32, the substrate 1101 is turned over so that the first surface 1101A faces downwards, and a portion of the substrate 1101 is removed. For example, a polishing process or similar is performed to remove a portion of the substrate 1101. In the embodiment shown in Figure 32, one surface of the pixel separation film 1110 is exposed by removing a portion of the substrate 1101 during the polishing process. However, it is also possible to avoid exposing the pixel separation film 1110. The surface of the substrate 1101 exposed by the polishing process is defined as the second surface 1101B. 【0082】 Referring to Figure 33, a color filter (1102, 1103), a light transmission layer 1104, and a microlens 1105 are formed on the second surface 1101B. The color filters (1102, 1103) contained in adjacent pixels (PX1, PX2) transmit light of different colors to each other. The light-transmitting layer 1104 is shared by adjacent pixels (PX1, PX2), and the microlenses 1105 are arranged separately for each pixel (PX1, PX2). Therefore, multiple photodiodes (PD1, PD2) are placed below a single microlens 1105. 【0083】 Figures 34 to 41 illustrate a method for manufacturing an image sensor according to another embodiment of the present invention. First, referring to Figure 34, in order to manufacture the image sensor, a first trench T1 and a second trench T2 are formed in a substrate 1201 containing semiconductor material. Referring to both Figure 34 and Figure 35, which shows a cross-section in the IX-IX' direction, the first trench T1 and the second trench T2 extend from the first surface 1201A of the substrate 1201 and are formed simultaneously by the etching process. For example, the first trench T1 has a first length d1 in a first direction (Z-axis direction) perpendicular to the first surface 1201A of the substrate 1201, and the second trench T1 has a second length d2 that is shorter than the first length d1. Furthermore, in the direction parallel to the first surface 1201A, the width of the first trench T1 is greater than the width of the second trench T2. The first trench T1 defines the pixel regions (PA1 to PA4), and the second trench T2 is placed inside each of the pixel regions (PA1 to PA4). 【0084】 Next, referring to Figure 36, impurities are injected through the second trench T2. The impurity injection process forms an impurity region 1240 in the lower part of the second trench T2. As an example, the impurity region 1240 is provided as a charge path between photodiodes formed on both sides of the second trench T2 and contains a P-type impurity. However, depending on the embodiment, the impurity region 1240 may also contain N-type impurities. As shown in Figure 36, by forming the second trench T2 together with the first trench T1 and performing the impurity implantation process, the impurity implantation process can be completed at a low energy level. Depending on the embodiment, the impurity region 1240 can also be formed to substantially the same depth as the bottom surface of the first trench T1. 【0085】 Referring to Figures 37 and 38, a predetermined material is packed into the first trench T1 and the second trench T2 to form the pixel separation membrane 1210 and the first pixel internal separation membrane 1221. Furthermore, photodiodes (PD1, PD2) are formed inside the substrate 1201, and pixel circuits are formed on the first surface 1201A. The pixel circuit includes floating diffusions (FD1, FD2), multiple elements 1230, wiring patterns 1231, etc., and is covered by an insulating layer 1232. 【0086】 The pixel separation film 1210 and the pixel internal separation film 1220 are formed by embedding a material such as polysilicon in the first trench T1 and the second trench T2. As described above with reference to Figure 36, the impurity injection process is performed through the second trench T2 to form the impurity region 1240, so that the first pixel internal separation membrane 1221 and the impurity region 1240 can be precisely aligned. 【0087】 Referring to Figure 39, after turning the substrate 1201 over, a polishing process is performed. One surface of the substrate 1201 that is exposed by the polishing process is defined as the second surface 1201B. For example, the polishing process is carried out until one surface of the pixel separation film 1210 forms a coplane with the second surface 1201B. Therefore, as shown in Figure 39, the pixel separation film 1210 penetrates the substrate 1201. 【0088】 Referring to Figure 40, a second pixel internal separation film 1222 is formed, extending from the second surface 1201B. The second pixel internal separation membrane 1222 is formed so as to be aligned with the impurity region 1240 and the first pixel separation membrane 1221 in the second direction (X-axis direction) and the third direction (Y-axis direction). In other words, the second pixel internal separation membrane 1222 is formed on top of the impurity region 1240 and, together with the first pixel internal separation membrane 1221, provides the pixel internal separation membrane 1220. 【0089】 In one embodiment shown in Figure 40, the second pixel internal separation membrane 1222 has the same shape as the first pixel internal separation membrane 1221. However, depending on the embodiment, the second pixel internal separation membrane 1222 may have a different shape from the first pixel internal separation membrane 1221. For example, unlike the first pixel internal separation membrane 1221 which extends along the third direction, the second pixel internal separation membrane 1222 can also be extended along the second direction, or any other direction that intersects the second and third directions. Furthermore, depending on the embodiment, the second pixel internal separation film 1222 may not be formed. 【0090】 Next, referring to Figure 41, a color filter (1202, 1203), a light transmission layer 1204, and a microlens 1205 are formed on the substrate 1201. The color filters (1202, 1203) contained in the adjacent first pixel PX1 and second pixel PX2 respectively transmit light of different colors to each other. Additionally, one microlens 1205 is placed in each pixel (PX1, PX2). Therefore, multiple photodiodes (PD1, PD2) are arranged below a single microlens 1205. 【0091】 Figures 42 and 43 are block diagrams showing a schematic configuration of an electronic device including an image sensor according to one embodiment of the present invention. Referring to Figure 42, the electronic device 2000 includes a camera module group 2100, an application processor 2200, a PMIC 2300, and an external memory 2400. The camera module group 2100 includes multiple camera modules (2100a, 2100b, 2100c). 【0092】 The figure shows an embodiment in which three camera modules (2100a, 2100b, and 2100c) are arranged, but the embodiments are not limited to these. In some embodiments, the camera module group 2100 can be modified and implemented to include only two camera modules. Furthermore, in some embodiments, the camera module group 2100 can be modified and implemented to include n camera modules (where n is a natural number greater than or equal to 4). Furthermore, in one embodiment, at least one of the multiple camera modules (2100a, 2100b, 2100c) included in the camera module group 2100 may include an image sensor according to one of the embodiments described above with reference to Figures 1 to 41. 【0093】 The detailed configuration of camera module 2100b will be described in more detail below with reference to Figure 43, but the following description can also be applied to other camera modules (2100a, 2100b) depending on the embodiment. Referring to Figure 43, the camera module 2100b includes a prism 2105, an optical path folding element (OPFE) 2110, an actuator 2130, an image sensing device 2140, and a storage unit 2150. 【0094】 The prism 2105 includes a reflective surface 2107 made of light-reflecting material and deforms the path of light L incident from the outside. In some embodiments, the prism 2105 causes the path of light L incident in a first direction X to be changed to a second direction Y perpendicular to the first direction X. Furthermore, the prism 2105 rotates the reflective surface 2107 of the light-reflecting material in direction A around the central axis 2106, or rotates the central axis 2106 in direction B, thereby changing the path of light L incident in the first direction X to the perpendicular second direction Y. At this time, OPFE2110 also moves in a third direction Z, which is perpendicular to the first direction X and the second direction Y. 【0095】 In some embodiments, as shown in the figure, the maximum rotation angle of the prism 2105 in the A direction may be 15 degrees or less in the positive (+) A direction and greater than 15 degrees in the negative (-) A direction, but the embodiments are not limited to these. In some embodiments, the prism 2105 can be moved approximately 20 degrees in the positive (+) or negative (-)B direction, or between 10 and 20 degrees, or between 15 and 20 degrees, where the angle of movement can be the same angle in the positive (+) or negative (-)B direction, or within a range of approximately 1 degree to approximately the same angle. In some embodiments, the prism 2105 can move the reflective surface 2106 of the light-reflecting material in a third direction (e.g., the Z direction) parallel to the extension direction of the central axis 2106. 【0096】 The OPFE2110 includes, for example, an optical lens consisting of m (where m is a natural number) groups. The m lenses move in the second direction Y to change the optical zoom ratio of the camera module 2100b. For example, if the basic optical zoom magnification of the camera module 2100b is Z, then when the m optical lenses included in the OPFE 2110 are moved, the optical zoom magnification of the camera module 2100b can be changed to 3Z, 5Z, or 5Z or greater. 【0097】 The actuator 2130 can move the OPFE 2110 or the optical lens (hereinafter referred to as the optical lens) to a specific position. For example, the actuator 2130 can adjust the position of the optical lens so that the image sensor 2142 is positioned at the focal length of the optical lens for accurate sensing. 【0098】 The image sensing device 2140 includes an image sensor 2142, control logic 2144, and memory 2146. The image sensor 2142 senses an image of the object to be sensed using light L provided through an optical lens. The control logic 2144 controls the overall operation of the camera module 2100b. For example, the control logic 2144 controls the operation of the camera module 2100b in accordance with the control signals provided via the control signal line CSLb. 【0099】 Memory 2146 stores information necessary for the operation of the camera module 2100b, such as calibration data 2147. Calibration data 2147 contains information necessary for the camera module 2100b to generate image data using light L supplied from an external source. The calibration data 2147 may include, for example, information regarding the degree of rotation, focal length, and optical axis, as mentioned above. If the camera module 2100b is implemented as a multi-state camera in which the focal length changes depending on the position of the optical lens, the calibration data 2147 may include the focal length values ​​for each position (or state) of the optical lens and information related to autofocusing. 【0100】 The storage unit 2150 stores image data sensed via the image sensor 2142. The storage unit 2150 may be located outside the image sensing device 2140 and may be implemented in a stacked configuration with the sensor chips constituting the image sensing device 2140. In some embodiments, the storage unit 2150 can be implemented using EEPROM (Electrically Erasable Programmable Read-Only Memory), but the embodiments are not limited to these. 【0101】 Referring to both Figures 42 and 43, in some embodiments, each of the multiple camera modules (2100a, 2100b, 2100c) includes an actuator 2130. As a result, each of the multiple camera modules (2100a, 2100b, 2100c) contains identical or different calibration data 2147 resulting from the operation of the actuator 2130 contained within it. 【0102】 In some embodiments, one of the multiple camera modules (2100a, 2100b, 2100c) (e.g., 2100b) may be a folded lens type camera module including the prism 2105 and OPFE 2110 described above, while the remaining camera modules (e.g., 2100a, 2100b) may be vertical type camera modules that do not include the prism 2105 and OPFE 2110, but the embodiments are not limited to these. 【0103】 In some embodiments, one of the multiple camera modules (2100a, 2100b, 2100c) (for example, 2100c) may be a vertical depth camera that extracts depth information using, for example, IR (Infrared Ray). In this case, the application processor 2200 can merge the image data provided by such a depth camera with the image data provided by other camera modules (e.g., 2100a or 2100b) to generate a 3D depth image. 【0104】 In some embodiments, at least two of the multiple camera modules (2100a, 2100b, 2100c) (e.g., 2100a, 2100b) may have different fields of view (angles of view). In this case, for example, the optical lenses of at least two of the camera modules (e.g., 2100a and 2100b) among the multiple camera modules (2100a, 2100b, and 2100c) may be different from each other, but are not limited to these. 【0105】 Furthermore, in some embodiments, the field of view of each of the multiple camera modules (2100a, 2100b, 2100c) may differ from one another. In this case, the optical lenses included in each of the multiple camera modules (2100a, 2100b, 2100c) may be different from each other, but are not limited to these. 【0106】 In some embodiments, each of the multiple camera modules (2100a, 2100b, 2100c) can be arranged physically separated from one another. In other words, instead of multiple camera modules (2100a, 2100b, 2100c) dividing and using the sensing area of ​​a single image sensor 2142, an independent image sensor 2142 can be placed inside each of the multiple camera modules (2100a, 2100b, 2100c). 【0107】 Referring further to Figure 42, the application processor 2200 includes an image processing unit 2210, a memory controller 2220, and internal memory 2230. The application processor 2200 can be implemented separately from multiple camera modules (2100a, 2100b, 2100c). For example, the application processor 2200 and multiple camera modules (2100a, 2100b, 2100c) can be implemented on separate semiconductor chips, isolated from each other. 【0108】 The image processing unit 2210 includes a plurality of sub-image processors (2212a, 2212b, 2212c), an image generator 2214, and a camera module controller 2216. The image processing unit 2210 includes multiple sub-image processors (2212a, 2212b, 2212c) in a number corresponding to the number of camera modules (2100a, 2100b, 2100c). 【0109】 Image data generated from each camera module (2100a, 2100b, 2100c) is provided to the corresponding sub-image processors (2212a, 2212b, 2212c) via separate image signal lines (ISLa, ISLb, ISLc). For example, image data generated from camera module 2100a is provided to sub-image processor 2212a via image signal line ISLa, image data generated from camera module 2100b is provided to sub-image processor 2212b via image signal line ISLb, and image data generated from camera module 2100c is provided to sub-image processor 2212c via image signal line ISLc. Such image data can be transmitted, for example, using a Camera Serial Interface (CSI) based on MIPI (Mobile Industry Processor Interface), but the embodiments are not limited to these. 【0110】 On the other hand, in some embodiments, a single sub-image processor can be arranged to support multiple camera modules. For example, instead of the sub-image processors 2212a and 2212c being implemented separately as shown in the figure, they are integrated into a single sub-image processor, and the image data provided from camera modules 2100a and 2100c can be selected by a selection element (e.g., a multiplexer) and then provided to the integrated sub-image processor. 【0111】 The image data provided to each sub-image processor (2212a, 2212b, 2212c) is then provided to the image generator 2214. The image generator 2214 generates an output image using image data provided by the respective sub-image processors (2212a, 2212b, 2212c) according to the generating information or mode signal. 【0112】 Specifically, the image generator 2214 generates an output image by merging at least a portion of the image data generated from camera modules (2100a, 2100b, 2100c) having different field-of-view angles, according to the image generation information or mode signal. Furthermore, the image generator 2214 selects one of the image data generated from camera modules (2100a, 2100b, 2100c) having different field-of-view angles, according to the image generation information or mode signal, and generates an output image. In some embodiments, the image generation information may include a zoom signal (or zoom factor). In some embodiments, the mode signal may be a signal based on a mode selected by the user, for example. 【0113】 If the image generation information is a zoom signal (zoom factor), and each camera module (2100a, 2100b, 2100c) has a different field of view (field of view angle), the image generator 2214 will perform different operations depending on the type of zoom signal. For example, if the zoom signal is the first signal, the image data output from camera module 2100a and the image data output from camera module 2100c are merged, and then the merged image signal and the image data output from camera module 2100b that was not used for merging are used to generate the output image. If the zoom signal is a second signal different from the first signal, the image generator 2214 does not merge such image data, but instead selects one of the image data output from each camera module (2100a, 2100b, 2100c) to generate the output image. However, the embodiments are not limited to these, and the methods for processing image data can be modified and implemented in any way as needed. 【0114】 In some embodiments, the image generator 2214 can receive multiple image data with different exposure times from at least one of the multiple sub-image processors (2212a, 2212b, 2212c), and perform HDR (high dynamic range) processing on the multiple image data to generate merged image data with an increased dynamic range. 【0115】 The camera module controller 2216 provides control signals to each camera module (2100a, 2100b, 2100c). Control signals generated by the camera module controller 2216 are provided to the corresponding camera modules (2100a, 2100b, 2100c) via mutually isolated control signal lines (CSLa, CSLb, CSLc). 【0116】 One of the multiple camera modules (2100a, 2100b, 2100c) is designated as the master camera (e.g., 2100b) depending on the image generation information or mode signal, including the zoom signal, while the remaining camera modules (e.g., 2100a, 2100c) are designated as slave cameras. This information is included in the control signals and provided to the corresponding camera modules (2100a, 2100b, 2100c) via separate control signal lines (CSLa, CSLb, CSLc). 【0117】 Depending on the zoom factor or operating mode signal, the camera modules operating as master and slave can be changed. For example, if camera module 2100a has a wider field of view than camera module 2100b and exhibits a lower zoom factor, camera module 2100b can operate as the master and camera module 2100a can operate as the slave. Conversely, when the zoom factor indicates a high zoom magnification, camera module 2100a can operate as the master and camera module 2100b can operate as the slave. 【0118】 In some embodiments, the control signals provided from the camera module controller 2216 to each camera module (2100a, 2100b, 2100c) include a sync enable signal. For example, if camera module 2100b is the master camera and camera modules (2100a, 2100c) are slave cameras, the camera module controller 2216 transmits a sink enable signal to camera module 2100b. Camera module 2100b, having received such a sync enable signal, generates a sync signal based on the provided sync enable signal and provides the generated sync signal to camera modules (2100a, 2100c) via the sync signal line SSL. Camera module 2100b and camera modules (2100a, 2100c) are synchronized by such a sync signal and transmit image data to the application processor 2200. 【0119】 In some embodiments, the control signals provided from the camera module controller 2216 to multiple camera modules (2100a, 2100b, 2100c) include mode information corresponding to the mode signal. Based on this mode information, the multiple camera modules (2100a, 2100b, 2100c) operate in a first operating mode and a second operating mode in relation to the sensing speed. 【0120】 Multiple camera modules (2100a, 2100b, 2100c) generate an image signal at a first speed in the first operating mode (for example, an image signal at a first frame rate), encode it at a second speed higher than the first speed (for example, an image signal at a second frame rate higher than the first frame rate), and transmit the encoded image signal to the application processor 2200. In this case, the second velocity may be 30 times or less the first velocity. 【0121】 The application processor 2200 stores the received image signal, i.e., the encoded image signal, in an internal memory 2230 or an external storage 2400. Then, it reads the encoded image signal from the memory 2230 or storage 2400, decodes it, and displays the image data generated based on the decoded image signal. For example, among the multiple subprocessors (2212a, 2212b, 2212c) of the image processing device 2210, the corresponding subprocessor performs decoding and then processes the decoded image signal. 【0122】 Multiple camera modules (2100a, 2100b, 2100c) generate image signals at a third speed lower than the first speed in the second operating mode (for example, generating image signals at a third frame rate lower than the first frame rate) and transmit the image signals to the application processor 2200. The image signal provided to the application processor 2200 may be an unencoded signal. The application processor 2200 either performs image processing on the received image signal or stores the image signal in the memory 2230 or storage 2400. 【0123】 The PMIC2300 supplies power, such as power supply voltage, to each of the multiple camera modules (2100a, 2100b, 2100c). For example, under the control of the application processor 2200, the PMIC 2300 supplies first power to camera module 2100a via power signal line PSLa, second power to camera module 2100b via power signal line PSLb, and third power to camera module 2100c via power signal line PSLc. 【0124】 The PMIC2300 responds to the power control signal PCON from the application processor 2200 to generate and adjust the power levels for each of the multiple camera modules (2100a, 2100b, 2100c). The power control signal PCON includes power adjustment signals for each operating mode of multiple camera modules (2100a, 2100b, 2100c). For example, the operating mode may include a low power mode. In this case, the power control signal PCON includes information about the camera module operating in low-power mode and the power level to be set. The power levels supplied to each of the multiple camera modules (2100a, 2100b, 2100c) may be the same or different from each other. Furthermore, the power level can be changed dynamically. 【0125】 Furthermore, the present invention is not limited to the embodiments described above. It can be modified and implemented in various ways without departing from the technical scope of the present invention. [Explanation of Symbols] 【0126】 Image sensors 1, 200, 200A, 200B, 300, 400, 400A 10-pixel array 20 Logic Circuits 21 Low Driver 22. Lead-out circuit 23 Column Driver 24 Control Logic 100, 100A, 100B pixel arrays 110, 110A (standard) pixels 110B Pixel Group 120 (autofocus) pixels 201, 301 circuit boards 202, 203, 302, 303 color filters 204, 304 Light transmission layer 205, 305 Microlenses 210, 310, 410 pixel separation membrane 211 First Pixel Separation Film 212 Second Pixel Separation Membrane 220, 320, 420, 420A Pixel Internal Separation Membrane 221, 321 First pixel internal separation membrane 222, 322 Second Pixel Internal Separation Membrane 230, 330 Multiple elements 231, 331 Wiring Patterns 232, 332 insulating layer 240 Impurity region FD1, FD2 (1st, 2nd) Floating Diffusion PD1, PD2 (first and second) photodiodes PX1~PX4 pixels

Claims

[Claim 1] The device includes a plurality of pixels arranged along a direction parallel to the upper surface of a substrate, and a pixel isolation film disposed between the plurality of pixels, wherein each of the plurality of pixels is a pixel array including at least one photodiode and a pixel circuit below the at least one photodiode. The system includes a logic circuit that acquires pixel signals from the plurality of pixels, The aforementioned pixel array includes at least one autofocus pixel, The autofocus pixel includes a first photodiode, a second photodiode, a pixel internal isolation film disposed between the first and second photodiodes, and a microlens disposed above the first and second photodiodes. The pixel internal isolation membrane includes a first pixel internal isolation membrane and a second pixel internal isolation membrane that are separated from each other in a first direction perpendicular to the upper surface of the substrate. The first pixel internal separation membrane and the second pixel internal separation membrane comprise different materials from each other. In a plane parallel to the upper surface of the substrate, the first pixel internal separation film is extended in a second direction. The image sensor is characterized in that the second pixel internal isolation membrane is extended in a third direction different from the second direction. [Claim 2] The first pixel internal isolation membrane extends from the pixel circuit and contains polysilicon. The image sensor according to claim 1, characterized in that the second pixel internal isolation film includes an insulating material. [Claim 3] The image sensor according to claim 2, characterized in that a negative voltage is input to the first pixel internal isolation film from the pixel circuit while the logic circuit acquires the pixel signals from the plurality of pixels. [Claim 4] The image sensor according to claim 2, characterized in that the first pixel internal separation film and the second pixel internal separation film have different lengths in one direction parallel to the upper surface of the substrate. [Claim 5] The image sensor according to claim 4, characterized in that, in the aforementioned one direction, the first pixel internal separation membrane is separated from the pixel separation membrane. [Claim 6] The image sensor according to claim 1, characterized in that the autofocus pixel is disposed between the first pixel internal separation membrane and the second pixel internal separation membrane and includes an impurity region doped with a P-type impurity. [Claim 7] The image sensor according to claim 1, characterized in that the pixel separation film includes a first pixel separation film extending from the pixel circuit and containing a first material, and a second pixel separation film extending from the first pixel separation film and containing a second material different from the first material. [Claim 8] The first pixel internal separation membrane comprises the first material, The image sensor according to claim 7, characterized in that the second pixel internal separation membrane includes the second material. [Claim 9] The image sensor according to claim 7, characterized in that the reflectance of the second material for light that has passed through the microlens or for light that has been directly incident on it is higher than the reflectance of the first material for light that has passed through the microlens or for light that has been directly incident on it. [Claim 10] A substrate having a first surface and a second surface facing the first surface, A pixel array comprising a pixel circuit including a plurality of pixels and a pixel isolation film disposed between the plurality of pixels and extending from the first surface to the second surface along a first direction perpendicular to the first surface, wherein each of the plurality of pixels has at least one photodiode disposed inside the substrate and a plurality of elements disposed on the first surface, The system includes a logic circuit that acquires pixel signals from the plurality of pixels, The aforementioned pixel array includes at least one autofocus pixel, The autofocus pixel includes a first photodiode, a second photodiode, a pixel internal isolation film extending from the first surface along the first direction between the first and second photodiodes, and a microlens disposed on the second surface. The pixel internal separation membrane includes a first pixel internal separation membrane extending from the first surface and a second pixel internal separation membrane extending from the second surface. The first pixel internal separation membrane and the second pixel internal separation membrane have different shapes in a plane parallel to the first surface. In a plane parallel to the first surface, the first pixel internal separation film is extended in a second direction. The image sensor is characterized in that the second pixel internal isolation membrane is extended in a third direction different from the second direction. [Claim 11] In a plane parallel to the first surface, the first pixel internal separation membrane and the second pixel internal separation membrane are extended in the second direction. The image sensor according to claim 10, characterized in that the length of the first pixel internal separation membrane and the length of the second pixel internal separation membrane are different from each other in the second direction. [Claim 12] The image sensor according to claim 11, characterized in that, in the second direction, the length of the first pixel internal separation membrane is shorter than the length of the second pixel internal separation membrane. [Claim 13] The image sensor according to claim 10, characterized in that, in a plane parallel to the first surface, the width of the pixel internal separation film is smaller than the width of the pixel separation film. [Claim 14] The image sensor according to claim 10, further comprising an impurity region disposed between the first pixel internal separation membrane and the second pixel internal separation membrane in the first direction, and doped with a P-type impurity. [Claim 15] The pixel separation membrane includes a first pixel separation membrane extending from the first surface along the first direction, and a second pixel separation membrane extending from the second surface and connected to the first pixel separation membrane. The image sensor according to claim 10, characterized in that, in the first direction, the length of the second pixel separation film is shorter than the length of the first pixel separation film. [Claim 16] The image sensor according to claim 15, characterized in that the reflectance of the second pixel separation film with respect to light that has passed through the microlens or is directly incident on it is higher than the reflectance of the first pixel separation film with respect to light that has passed through the microlens or is directly incident on it.

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