Image sensor

Abstract

To provide an image sensor with higher light-receiving efficiency.SOLUTION: An image sensor includes a plurality of pixels arranged in matrix, a photodiode provided for each pixel in a semiconductor substrate having a first surface to which light is incident and a second surface opposite to the first surface, a microlens provided on the first surface of the semiconductor substrate and condensing the light, a color filter provided between the semiconductor substrate and the microlens, and an optical path changing member that changes at least a part of a path of the light when the light travels toward the photodiode through the microlens.SELECTED DRAWING: Figure 5A

Description

[Technical field]

[0001] The present invention relates to an image sensor. [Background technology]

[0002] An image sensor is a device that converts an optical image into an electrical signal. Image sensors can be classified into charge coupled device (CCD) type and complementary metal oxide semiconductor (CMOS) type. The CMOS type image sensor is abbreviated as CIS (CMOS image sensor). The CIS includes a plurality of pixels arranged two-dimensionally.

[0003] Each pixel includes a photodiode (PD) formed in a semiconductor substrate and a microlens provided on the semiconductor substrate. The photodiode converts incident light into an electrical signal, and the microlens focuses the light onto the photodiode.

[0004] However, if the light collected by the microlens does not travel to the photodiode, the light receiving efficiency of the photodiode decreases, and therefore an improvement in this regard is required. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent Publication No. 2023 / 0040060 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to provide an image sensor having improved light receiving efficiency and an improved crosstalk phenomenon caused by oblique light. [Means for solving the problem]

[0007] According to one embodiment of the present invention, an image sensor including a plurality of pixels arranged in a matrix includes a photodiode provided for each pixel in a semiconductor substrate having a first surface into which light is incident and a second surface opposite to the first surface, a microlens provided on the first surface of the semiconductor substrate to collect the light, a color filter provided between the semiconductor substrate and the microlens, and a light path changing member that changes a path of at least a portion of the light when the light travels through the microlens toward the photodiode, the light path changing member extending from the first surface of the semiconductor substrate and having a curved surface that is concave or convex along a direction toward the second surface.

[0008] In one embodiment of the present invention, at least two pixels among the plurality of pixels share one microlens among the microlenses, and the light path changing member can be provided in the center of the at least two pixels that share the microlens in a planar view.

[0009] In one embodiment of the present invention, the optical path changing member may have a curved surface that is concave or convex along a direction from the first surface to the second surface.

[0010] In an embodiment of the present invention, the recess may be filled with an insulating material, or the recess may be filled with any one of the color filters.

[0011] According to an embodiment of the present invention, the image sensor may include a plurality of pixel groups each having one of first to third colors, and each pixel group may be formed of first to fourth pixels arranged in a 2x2 matrix shape. In this case, the image sensor may include a semiconductor substrate having a first surface to which light is incident and a second surface opposite to the first surface, photodiodes provided in the first to fourth pixels, microlenses provided on the first surface of the semiconductor substrate corresponding to the first to fourth pixels and condensing the light, color filters provided between the semiconductor substrate and the microlenses, and a light path changing member changing a path of at least a part of the light when the light travels toward the photodiode through the microlenses, and the light path changing member may have a curved surface extending from the first surface of the semiconductor substrate and recessed or bulging along a direction toward the second surface.

[0012] A method for manufacturing an image sensor according to an embodiment of the present invention includes the steps of: providing a semiconductor substrate on which a photodiode and a pixel separator are formed, the semiconductor substrate having a first surface and a second surface opposite to the first surface; forming a light path changing member on the first surface of the semiconductor substrate in an area overlapping with the pixel separator in a plan view; forming a color filter on the semiconductor substrate on which the light path changing member is formed; and forming a microlens on the semiconductor substrate on which the color filter is formed, the light path changing member may have a curved surface extending from the first surface of the semiconductor substrate and concave or convex in a direction toward the second surface. Effect of the Invention

[0013] According to an embodiment of the present invention, there is provided an image sensor having improved light receiving efficiency, and an image sensor having an improved crosstalk phenomenon caused by oblique light. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is a block diagram of an image sensor according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating a pixel array including a plurality of pixel groups in an image sensor according to an embodiment of the inventive concept; [Diagram 3] 1 is a diagram showing a circuit diagram of a pixel. [Figure 4A] FIG. 2B is a plan view showing the P1 portion in FIG. 2A. [Figure 4B] FIG. 4A is a plan view showing the second pixel group. [Figure 5A] FIG. 4C is a cross-sectional view taken along line AA' in FIG. 4B. [Figure 5B] FIG. 4C is a cross-sectional view taken along line BB' in FIG. 4B. [Figure 6] FIG. 4B is a plan view of an image sensor according to an embodiment of the present invention, corresponding to the second pixel group PXG2 of FIG. 4A. [Figure 7] FIG. 7 is a cross-sectional view taken along line AA' in FIG. [Figure 8] 4B is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 4A. [Figure 9] 4B is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 4A. [Figure 10] 4B is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 4A. [Figure 11] 4B is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 4A. [Figure 12A] FIG. 4B is a plan view of an image sensor according to an embodiment of the present invention, corresponding to a second pixel group of FIG. 4A. [Figure 12B] FIG. 12B is a cross-sectional view taken along line AA' in FIG. 12A. [Figure 13]4B is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of the plan view corresponding to the second pixel group of FIG. 4A. [Figure 14A] 4B is a plan view corresponding to a second pixel group in FIG. 4A in an image sensor according to an embodiment of the present invention; [Figure 14B] 4B is a plan view corresponding to a second pixel group in FIG. 4A in an image sensor according to an embodiment of the present invention; [Figure 15A] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 15B] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 15C] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 15D] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 15E] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 15F] 5B is a cross-sectional view sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 5A. [Figure 16A] 9A to 9C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 8. [Figure 16B] 9A to 9C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 8. [Figure 16C] 9A to 9C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 8. [Figure 17A] 10A to 10C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 9, in which steps substantially the same as those in the above-described embodiment are omitted. [Figure 17B] 10A to 10C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 9, in which steps substantially the same as those in the above-described embodiment are omitted. [Figure 17C]10A to 10C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. 9, in which steps substantially the same as those in the above-described embodiment are omitted. [Figure 18A] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18B] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18C] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18D] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18E] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18F] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 18G] 11A to 11C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor illustrated in FIG. [Figure 19] 13 is a diagram illustrating a pixel array including a plurality of pixel groups according to another embodiment of the present invention. [Figure 20] 20 is a plan view showing the P2 portion in FIG. [Figure 21] 21 is a cross-sectional view taken along line AA' in FIG. 20. [Figure 22] 21 is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 20. [Diagram 23] 21 is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 20. [Figure 24] 21 is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 20. [Diagram 25] 21 is a cross-sectional view of an image sensor according to an embodiment of the present invention taken along line AA' of FIG. 20. [Figure 26A] 1 illustrates a pixel array according to another embodiment of the present invention. [Figure 26B] 26B is a plan view showing the P3 portion in FIG. 26A. [Figure 27A] 13 is a diagram illustrating a pixel array according to another embodiment of the present invention. [Figure 27B] 27B is a plan view showing the P4 portion in FIG. 27A. [Figure 28] 13 is a diagram showing a pixel array according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Since the present invention can be modified in various ways and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text, but it should be understood that this is not intended to limit the present invention to the specific embodiments, and that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention.

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] The present invention relates to an image sensor including a pixel array made up of a plurality of pixels, and various embodiments will be described below. The image sensor of the present invention includes a photodiode that receives light of various wavelengths and converts it into an electrical signal, and particularly corresponds to an image sensor with increased light efficiency and reduced crosstalk. Here, the light of various wavelengths mainly means light of a visible light wavelength band, but is not limited thereto, and may be light of other wavelengths other than visible light, for example, infrared light or ultraviolet light. The image sensor according to an embodiment of the present invention can detect various colors of light, for example, light of blue, green, red, etc., in the visible light wavelength band. To this end, the image sensor according to an embodiment of the present invention may include a photodiode, for example, a photodiode, formed corresponding to each pixel in a semiconductor substrate 100 to which light is incident. Here, a microlens is provided adjacent to an incident surface to collect light incident on the photodiode, and according to an embodiment of the present invention, a structure is provided in which the light collected by the microlens is evenly distributed to the corresponding pixel.

[0018] Hereinafter, an image sensor according to an embodiment of the present invention will be described. First, a block diagram of the image sensor and a corresponding circuit diagram will be described, and then a detailed configuration will be described.

[0019] FIG. 1 is a block diagram of an image sensor according to an embodiment of the present invention.

[0020] Referring to FIG. 1, an image sensor according to an embodiment of the present invention includes a pixel array (1), a row decoder (2), a row driver (3), a column decoder (4), a timing generator (5), a correlated double sampler (CDS; 6), an analog to digital converter (ADC; 7), and an input / output buffer (I / O buffer; 8).

[0021] The pixel array 1 includes a plurality of pixels arranged two-dimensionally, and converts optical signals into electrical signals. The pixel array 1 can be driven by a plurality of driving signals, such as a pixel selection signal, a reset signal, and a charge transfer signal, from a row driver 3. The converted electrical signals are provided to a correlated double sampler 6.

[0022] The row driver 3 provides a number of drive signals to the pixel array 1 for driving a number of pixels according to the result decoded by the row decoder 2. When the pixels are arranged in a matrix, a drive signal can be provided for each row.

[0023] A timing generator 5 provides timing and control signals to the row decoder 2 and the column decoder 4 .

[0024] The correlated double sampler 6 receives, holds, and samples the electrical signal generated by the pixel array 1. The correlated double sampler double samples a specific noise level and a signal level according to an electrical signal, and outputs a difference level corresponding to the difference between the noise level and the signal level.

[0025] The analog-to-digital converter 7 converts the analog signal corresponding to the difference level output from the correlated double sampler 6 into a digital signal and outputs it.

[0026] The input / output buffer 8 latches the digital signal, and outputs the signal latched by the input / output buffer as a digital signal to a video video signal processor (not shown).

[0027] Fig. 2 is a diagram showing a pixel array including a plurality of pixel groups according to an embodiment of the present invention in an image sensor according to an embodiment of the present invention, and Fig. 3 is a diagram showing a circuit diagram of a pixel. In Fig. 3, each pixel has substantially the same configuration and operation in terms of a circuit, so for the sake of simplicity, only one pixel will be described.

[0028] Referring to FIG. 2, in one embodiment of the present invention, a pixel array includes a plurality of pixel groups PXG.

[0029] One pixel group PXG may include first to fourth pixels PX1, PX2, PX3, and PX4 arranged in a 2×2 matrix. Here, the row direction is a first direction D1, the column direction is a second direction D2, and one pixel group PXG may include four pixels PX. According to the present embodiment, a plurality of pixel groups PXG may be arranged in a matrix to form an image sensor.

[0030] A pixel group PXG may be arranged in a matrix shape along a first direction D1 and a second direction D2 that intersect with each other. In the drawing, a direction perpendicular to the first direction D1 and the second direction D2 is a third direction D3.

[0031] One pixel group PXG may include first to fourth pixels PX1, PX2, PX3, and PX4 arranged in a 2×2 matrix, where the row direction is a first direction D1, the column direction is a second direction D2, and the first and second pixels PX1, PX2 and the third and fourth pixels PX3, PX4 are sequentially arranged along the first direction D1, with the first and second pixels PX1, PX2 forming a first row and the third and fourth pixels PX3, PX4 forming a second row.

[0032] Each of the first to fourth pixels PX1, PX2, PX3, and PX4 may include a first sub-pixel SPX1 and a second sub-pixel SPX2. The first and second sub-pixels SPX1 and SPX2 may be sequentially arranged along a first direction D1.

[0033] Each pixel group PXG may be assigned one of the reference colors, and the first through fourth pixels PX1, PX2, PX3, and PX4 in each pixel group PXG may have one color assigned from the reference colors. For example, one pixel group PXG may be assigned a green color, and in this case, the first through fourth pixels PX1, PX2, PX3, and PX4 may all have a green color filter.

[0034] The pixel groups PXG each have one color, and when multiple pixel groups PXG are arranged, they may be generally formed into a Bayer pattern. For example, when four pixel groups PXG are arranged to have a 2x2 matrix shape, two of the pixel groups PXG in the first row may have blue and green colors, respectively, and two of the pixel groups PXG in the second row may have green and red colors.

[0035] The pixel groups PXG each have one color, and when multiple pixel groups PXG are arranged, they may be generally formed in a Bayer pattern. For example, when four pixel groups PXG are arranged to have a 2×2 matrix shape, two of the pixel groups PXG in the first row may have blue and green colors, and two of the pixel groups PXG in the second row may have green and red colors.

[0036] Examples of the reference colors include RGB (red, green, blue), RGBW (red, green, blue, white), CMY (cyan, magenta, yellow), CMYK (cyan, magenta, yellow, black), RYB (red, yellow, blue), and RGBIR (infrared ray). In an embodiment of the present invention, the first to third colors are described as blue (B), green (G), and red (R), but are not limited thereto.

[0037] The colors of the first to fourth pixels PX1, PX2, PX3, and PX4 may be realized by color filters CF corresponding to each pixel PX. If an array of color filters CF corresponding to each pixel PX is called a color filter array, the color filter array may include first to third color filters CF1, CF2, and CF3 corresponding to each pixel PX. According to an embodiment of the present invention, the first to third color filters CF1, CF2, and CF3 may represent blue, green, and red colors, respectively, and the first pixel PX1 may correspond to the first color filter CF1, the second pixel PX2 may correspond to the second color filter CF2, the third pixel PX3 may correspond to the second color filter CF2, and the fourth pixel PX4 may correspond to the third color filter CF3.

[0038] For convenience of explanation, the Bayer pattern, i.e., the RGB pattern (or the RGGB pattern) will be mainly described below, but it should be noted that this does not limit the repeating arrangement structure and pattern of other color filter arrays. That is, an embodiment of the present invention is not limited thereto, and the color filter array may be formed in various patterns including RGB, CYYM, CYGM, RGBW, RYYB, and X-trans.

[0039] Referring to FIG. 3, a plurality of pixel groups included in an image sensor according to an embodiment of the present invention may include a pixel circuit PXC corresponding to each of the pixel groups. The pixel circuit PXC may include a plurality of semiconductor devices for processing charges generated in the photodiodes PD1, PD2, PD3, and PD4 as well as the photodiodes PD1, PD2, PD3, and PD4 included in each of the unit pixels PX. As an example, the pixel circuit PXC may include a first photodiode PD1, a second photodiode PD2, a third photodiode PD3, and a fourth photodiode PD4. The pixel circuit PXC may include first to fourth transfer transistors TX1, TX2, TX3, and TX4, a reset transistor RX, a selection transistor SX, and a driving transistor DX corresponding to each of the photodiodes PD1, PD2, PD3, and PD4. The photodiodes PD1, PD2, PD3, and PD4 included in the pixel circuit PXC may share a floating diffusion region FD, a reset transistor RX, a selection transistor SX, and a driving transistor DX.

[0040] Meanwhile, the gate electrodes of the transistors TX1, TX2, TX3, TX4, RX, SX, and DX included in the pixel circuit PXC may be connected to the driving signal line, respectively. As an example, the first to fourth transmission transistors TX1, TX2, TX3, and TX4 may operate by receiving transmission control signals TG1, TG2, TG3, and TG4 from a transmission control signal line, the reset transistor RX may operate by receiving a reset control signal RG from a reset control signal line, and the selection transistor SX may operate by receiving a selection control signal SG. However, this is only an embodiment and is not limited to what is shown in FIG. 2, and the pixel circuit may be designed in various ways. As an example, the pixel circuit may include a semiconductor device for processing charges generated in a photodiode in a unit larger or smaller than the unit pixel PX.

[0041] In one embodiment of the present invention, any one of the pixel circuits PXC generates a first electrical signal from charges generated in the photodiodes PD1, PD2, PD3, and PD4 included in the corresponding pixel circuit PXC and outputs the first electrical signal to a first column line, and the other pixel circuits generate a second electrical signal from charges generated in the photodiodes PD1, PD2, PD3, and PD4 included in the corresponding pixel circuit and output the second electrical signal to a second column line. According to one embodiment, two or more pixel circuits arranged adjacent to each other may share one first column line. Similarly, two or more other pixel circuits arranged adjacent to each other may share one second column line. The pixel circuits arranged adjacent to each other may share some semiconductor elements.

[0042] The first to fourth transfer transistors TX1, TX2, TX3, and TX4 may be connected to the first to fourth photodiodes PD1, PD2, PD3, and PD4, respectively. Meanwhile, the first to fourth transfer transistors TX1, TX2, TX3, and TX4 may share a floating diffusion region FD. The first to fourth photodiodes PD1, PD2, PD3, and PD4 may generate charges in proportion to the amount of light incident from the outside and accumulate the charges in each of the photodiodes.

[0043] The first to fourth transfer transistors TX1, TX2, TX3, and TX4 can sequentially transfer charges stored in the first to fourth photodiodes PD1, PD2, PD3, and PD4 to the floating diffusion region FD. Different transfer control signals TG1, TG2, TG3, and TG4 can be applied to the gate electrodes of the first to fourth transfer transistors TX1, TX2, TX3, and TX4 to transfer charges generated in one of the first to fourth photodiodes PD1, PD2, PD3, and PD4 to the floating diffusion region FD. Thus, the floating diffusion region FD can store charges generated in at least one of the first to fourth photodiodes PD1, PD2, PD3, and PD4.

[0044] The reset transistor RX may periodically reset the charge stored in the floating diffusion region FD. For example, an electrode of the reset transistor RX may be connected to the floating diffusion region FD and a power supply voltage VDD. When the reset transistor RX is turned on, the charge stored in the floating diffusion region FD is discharged due to a potential difference with the power supply voltage VDD, and the floating diffusion region FD is reset, so that the voltage of the floating diffusion region FD may become the same as the power supply voltage VDD.

[0045] The operation of the driving transistor DX can be controlled according to the amount of charge stored in the floating diffusion region FD. The driving transistor DX can function as a source follower buffer amplifier in combination with a current source disposed outside the unit pixel PX. For example, the driving transistor DX can amplify a potential change according to the charge stored in the floating diffusion region FD and output the amplified potential change to an output line Vout.

[0046] The selection transistor SX can select a unit pixel PX to be read out on a row-by-row basis. When the selection transistor SX is turned on, an electrical signal output from the driving transistor DX can be transferred to the selection transistor SX.

[0047] An image sensor according to an embodiment of the present invention may provide an auto focus function in at least one of a plurality of unit pixels based on the pixel circuit shown in Fig. 2. As an example, the image sensor may provide an auto focus function in four directions (e.g., up / down and left / right) using the first to fourth photodiodes PD1 to PD4.

[0048] For example, the logic circuit may provide an auto focus function in a vertical direction using pixel signals obtained from the first photodiode PD1 and the second photodiode PD2 and pixel signals obtained from the third photodiode PD3 and the fourth photodiode PD4. Meanwhile, the logic circuit may provide an auto focus function in a horizontal direction using pixel signals obtained from the first photodiode PD1 and the third photodiode PD3 and pixel signals obtained from the second photodiode PD2 and the fourth photodiode PD4. However, the pixel circuit of the unit pixel providing the auto focus function is not necessarily limited to that shown in FIG. 2, and some elements may be added or omitted as necessary.

[0049] Each pixel according to an embodiment of a pixel array having the above structure will now be described in more detail.

[0050] Figure 4A is a plan view showing portion P1 in Figure 2A, Figure 4B is a plan view showing the second pixel group in Figure 4A, and Figures 5A and 5B are cross-sectional views along lines A-A' and B-B' in Figure 4B, respectively.

[0051] 4A, 4B, 5A, and 5B, the image sensor includes a plurality of photodiodes PD provided for each pixel PX in a semiconductor substrate 100, color filters CF (CF1, CF2, CF3) provided on the photodiodes PD and having at least two different colors, microlenses ML provided on the color filters CF to collect light incident on the photodiodes PD through the color filters CF, and a light path changing member LM to change the path of the light traveling to the photodiodes PD through the microlenses ML.

[0052] Although not shown, additional components may or may not be interposed between the components of the image sensor according to an embodiment of the present invention, and the following embodiment mainly describes the main components for ease of explanation. For example, an additional insulating layer, a protective layer, etc. may be further provided between the semiconductor substrate 100 and the color filter CF, between the color filter CF and the microlens ML, etc.

[0053] The semiconductor substrate 100 includes a first surface 100a disposed in a direction in which light is incident, and a second surface 100b opposite to the first surface 100a. That is, in the semiconductor substrate 100 of the present invention, the first surface 100a serves as an incident surface.

[0054] The semiconductor substrate 100 may be a semiconductor substrate 100 including a semiconductor material, for example, a group IV semiconductor. For example, the group IV semiconductor may include silicon, germanium, or silicon-germanium. The substrate 100 may be provided as a bulk wafer, an epitaxial layer, a silicon on insulator (SOI) layer, a semiconductor on insulator (SeOI) layer, or the like. The substrate 100 may include an impurity region 12. For example, the semiconductor substrate 100 may be a p-type silicon semiconductor substrate 100. In an embodiment, the semiconductor substrate 100 may include a p-type bulk semiconductor substrate 100 and a p-type or n-type epitaxial layer grown thereon. Alternatively, the semiconductor substrate 100 may include an n-type bulk semiconductor substrate 100 and a p-type or n-type epitaxial layer grown thereon. According to an embodiment, the semiconductor substrate 100 may be an organic plastic semiconductor substrate 100. The image sensor may be, for example, a backside illumination type CMOS image sensor in which light is incident on the first surface 100a of the semiconductor substrate 100.

[0055] Although not shown, a passivation film including a plurality of stacked layers may be provided on the first surface 100a of the semiconductor substrate 100. The passivation film may include at least two of an aluminum oxide layer, a hafnium oxide layer, a tantalum oxide layer, a zirconium oxide layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon nitride layer. In an exemplary embodiment, the passivation film may include a fixed charge layer and / or an anti-reflection layer. The anti-reflection layer may be provided to adjust the refractive index so that the incident light can proceed to the photodiode PD with high transmittance.

[0056] The color filter CF is disposed behind the microlens ML based on the light travel path. The color filter CF may be provided between the semiconductor substrate 100 and the microlens ML. The color filter CF may transmit light having a specified reference color, i.e., light having a specified wavelength range.

[0057] The color filter CF may be disposed on the passivation film and the grid layer 160 above the photodiodes PD. For example, the color filter CF may transmit light of a specific wavelength to reach the photodiodes PD (PD1, PD2, PD3, PD4) below. The color filter CF may be realized as a color filter array made of red filters, green filters, and blue filters. The color filter CF may be made of a material in which a pigment containing a metal or metal oxide is mixed into a resin, for example.

[0058] The microlens ML may refract and / or focus incident light incident on the photodiode PD. In an embodiment of the present invention, a plurality of microlenses ML may be provided on the semiconductor substrate 100, and may correspond one-to-one to each pixel group PXG. That is, a plurality of pixels PX (e.g., first to fourth pixels PX1, PX2, PX3, and PX4) in one pixel group PXG may share one microlens ML. The microlens ML may be provided in a convex lens shape so that the microlens ML can receive and focus light to the maximum extent according to the direction in which the light is incident, i.e., the incident angle of the light.

[0059] The microlens ML may be made of a transparent polymer material. The microlens ML may be made of, for example, a transparent photosensitive material or a transparent thermosetting resin. The microlens ML may be made of, for example, a TMR series resin (a product of Tokyo Ohka Kogyo, Co.) or an MFR series resin (a product of Japan Synthetic Rubber Corporation). However, the material of the microlens ML is not limited thereto, and may be made of various materials.

[0060] The microlens ML may include a planarization film PLZ provided on the color filter CF and a microlens portion MLP provided on the planarization film PLZ. The planarization film PLZ is provided to planarize the upper surface of the color filter CF, which is not flat. In an embodiment of the present invention, the planarization film PLZ and the microlens portion MLP may be formed as separate components through separate processes using separate materials, but the present invention is not limited thereto, and the planarization film PLZ and the microlens portion MLP may be formed as an integral unit without being separated using the same material. In the following embodiment, for the sake of simplicity of explanation, the planarization film PLZ and the microlens portion MLP are commonly referred to as a microlens ML, which is a single component.

[0061] In the present embodiment, one pixel group PXG including the first to fourth pixels PX1, PX2, PX3, and PX4 may be provided with one microlens ML, i.e., the first to fourth pixels PX1, PX2, PX3, and PX4 in one pixel group PXG may share one microlens ML.

[0062] The photodiode PD can be used as a photoelectric conversion element by being disposed behind the microlens ML and the color filter CF. The photodiode PD can absorb incident light and generate and accumulate electric charges corresponding to the amount of light.

[0063] In the embodiment of the present invention, the photodiode PD is described as an example of the photoelectric conversion element, but the present invention is not limited thereto. Instead, the photodiode PD may be at least one of a phototransistor, a photogate, a pinned photodiode (PPD), and a combination thereof. When the photodiode PD is used as the photoelectric conversion element as in the present invention, the photodiode PD may include an impurity region having a different conductivity type from the semiconductor substrate 100 and may form a PN junction with a well region in the semiconductor substrate 100. When light reaches the photodiode PD, an electrical signal corresponding to the incident light can be output by the photoelectric effect. The electrical signal can generate a charge (or a current) according to the intensity (or amount) of the received light.

[0064] The light path changing member LM is provided between the semiconductor substrate 100 and the color filter CF to change the path of at least a portion of the incident light when the incident light travels toward the photodiode PD through the microlens ML, as will be described later.

[0065] In one embodiment of the present invention, each pixel PX may further include an element isolation portion 107, a pixel isolation portion 110, a pixel electrode 120 disposed in an insulating film 140, and a grid layer 160 disposed on the upper part of the semiconductor substrate 100.

[0066] The element isolation portion 107 may include an insulating material and may be disposed in the semiconductor substrate 100 at a predetermined depth from the second surface 100b of the semiconductor substrate 100. The element isolation portion 107 may be omitted depending on the configuration of the corresponding pixel PX.

[0067] The pixel separator 110 may be disposed in the semiconductor substrate 100 under the boundary of each pixel PX. The pixel separator 110 may be connected to the device separator 107 at the second surface 100b. However, depending on the embodiment, the arrangement of the pixel separator 110 in the semiconductor substrate 100 along the third direction D3 may be variously changed. The pixel separator 110 may be disposed to surround the photodiode PD. However, the relative arrangement of the pixel separator 110 and the photodiode PD is not limited to that shown in the drawings and may be variously changed in the embodiment. The pixel separator 110 may include an insulating material or a conductive material. For example, when the pixel separator 110 includes a conductive material, an insulating film may be further disposed between the pixel separator 110 and the semiconductor substrate 100.

[0068] The pixel electrode 120 may be disposed between the photodiode PD and the wiring structure 130. The pixel electrode 120 may constitute a pixel circuit of the pixel PX. For example, the pixel electrode 120 may include a transmission gate forming a transfer transistor. The transmission gate may be a vertical transistor gate including a portion extending from the second surface 100b of the semiconductor substrate 100 into the semiconductor substrate 100. The pixel electrode 120 may further include a floating diffusion region FD in the semiconductor substrate 100 and a gate on the second surface 100b of the semiconductor substrate 100 in addition to the transmission gate. The gate may constitute a source follower transistor, a reset transistor, and a selection transistor.

[0069] The grid layer 160 may be disposed between the color filters CF on the passivation film to separate the color filters CF from each other. The grid layer 160 may be disposed on a passivation film (not shown) and may be disposed below the boundary of each pixel PX. The grid layer 160 may be disposed on the pixel separator 110 in a third direction D3 that is perpendicular to one surface of the semiconductor substrate 100. The grid layer 160 may be provided in a multi-layer structure and may include at least one of a metal material, for example, titanium (Ti), titanium oxide, tantalum (Ta), and tantalum oxide. The grid layer may also be an insulating film that is a low refractive index (LRI) layer, and may have a refractive index in the range of, for example, about 1.1 to about 1.8. The grid layer 160 may include an insulating material, for example, an oxide or nitride including silicon (Si), aluminum (Al), or a combination thereof, and may include, for example, silicon oxide having a porous structure or silica nanoparticles having a network structure.

[0070] In one embodiment, as used herein, when the terms "about" or "substantially" are used in connection with a numerical value, the numerical value may include a tolerance of about ±10%. If a range is specified, the range includes all values ​​therebetween, such as in increments of 0.1%.

[0071] As described above, at least two pixels PX among the pixels PX may share one microlens ML among the microlenses ML. In this case, light incident through the corresponding microlens ML may have a focus at the central center of at least two pixels PX sharing the corresponding microlens ML, and as a result, light is collected at the central portions of at least two pixels PX. For example, according to an embodiment of the present invention, the pixels PX corresponding to one microlens ML correspond to one pixel group PXG including first to fourth pixels PX1, PX2, PX3, and PX4, and light incident on the one microlens ML is collected at the central portions of the first to fourth pixels PX1, PX2, PX3, and PX4. However, as described above, a pixel separator 110 is provided at the center of at least two pixels PX sharing the corresponding microlens ML, for example, at the center of the first to fourth pixels PX1, PX2, PX3, and PX4, to partition the pixels PX. As a result, light that should travel to the photodiode PD of a corresponding pixel PX, for example, the photodiode PD of each of the first to fourth pixels PX1, PX2, PX3, and PX4, is collected by the pixel separator 110, and the light may be absorbed by the pixel separator 110. Such absorption of light by the pixel separator 110 significantly reduces the light receiving efficiency of the photodiode PD. In addition, the pixel separator 110 may include a light absorbing material to prevent light traveling toward the pixel separator 110 from traveling to an adjacent pixel PX and causing crosstalk, in which case the absorption of the incident light may become even worse, and the light receiving efficiency may also be further reduced.

[0072] In one embodiment of the present invention, the light path changing member LM is provided at a position where the focal point of the microlens ML is disposed. That is, the light path changing member LM may be provided so as to overlap the focal point formed by the microlens ML in a plan view. Also, the light path changing member LM may be provided so as to overlap the pixel separating unit 110 in a plan view. Thus, the light path changing member LM changes the path of light traveling to the pixel separating unit 110. The changed light may travel to an area other than the pixel separating unit 110, for example, to the photodiode PD.

[0073] The light path changing member LM uses refraction, diffraction, and / or scattering to effectively change the path of light. In particular, the light path changing member LM uses the effect of refraction, diffraction, and / or scattering at an interface between materials with different refractive indexes (hereinafter, refraction will be described as an example). For this purpose, the light path changing member LM includes curved surfaces having various shapes, and the curved surfaces extend from the first surface of the semiconductor substrate 100. The light path changing member LM can be used by using materials arranged on both sides of the curved surface with different refractive indexes to induce refraction of light. Therefore, the light is refracted in a direction different from the original traveling direction while passing through the light path changing member LM, and the traveling direction of the light is changed through such refraction. In FIG. 5A, the path LP of the light passing through the corresponding microlens ML is simply illustrated by a dashed line.

[0074] In an embodiment of the present invention, the light path changing member LM may have a curved surface that is concave or convex in a direction from the first surface 100a to the second surface 100b of the semiconductor substrate 100. The light path changing member LM is formed by processing the first surface 100a of the semiconductor substrate 100. For example, the light path changing member LM may have a recess that is recessed in a direction from the first surface 100a to the second surface 100b as shown in the drawing. The recess may be filled with a material different from that of the semiconductor substrate 100 so as to have a refractive index different from that of the semiconductor substrate 100. For example, the recess may be filled with an insulating material different from that of the semiconductor substrate 100. The insulating material may be silicon oxide, silicon nitride, silicon oxynitride, various inorganic materials, and organic materials such as polyvinyl alcohol. The refractive index of light passing through the light path changing member LM may be determined according to the selection of the insulating material.

[0075] Here, the light path changing member LM may be a part of a sphere and may be circular in plan view. The light path changing member LM may have a shape that is symmetrical with respect to a line passing through the center, i.e., a rotationally symmetrical shape, even if it is not a part of a sphere.

[0076] In one embodiment of the present invention, the light path changing member LM may have various shapes, but may have a curved surface without a curved portion so that light is uniformly refracted and emitted in various directions toward the photodiode PD. When the light path changing member LM has a curved surface, it is possible to reduce the light being focused in only one direction at the curved portion.

[0077] According to one embodiment of the present invention, the provision of a light path changing member LM not only increases the light collection efficiency, but also guides light that can be absorbed in the pixel separator 110 to travel to the photodiode PD as much as possible, thereby increasing light efficiency and reducing interference caused by oblique light, thereby preventing crosstalk.

[0078] Also, according to an embodiment of the present invention, the light path changing member LM is directly formed on the first surface 100a, which is the light incident surface of the semiconductor substrate 100, so there is no need to change the light path through an additional structure. Additional structures for refracting light, such as adding a separate light path changing means between the semiconductor substrate and the color filter, patterning the color filter itself to create a shape for changing the light path, or disposing an additional microlens, all increase the light path, and of course, additional layers (e.g., additional insulating films) are required to dispose such structures, which ultimately increases the number of layers through which light must pass until it reaches the photodiode, increasing the thickness and reducing the light efficiency. An embodiment of the present invention solves this problem without forming an additional light path changing means.

[0079] In addition, in the present embodiment, one pixel group PXG includes first to fourth pixels PX1, PX2, PX3, and PX4 that are different from each other, and the photoelectric conversion signals of the photodiodes PD included in each pixel PX can be read out independently, and autofocusing can be performed by detecting a phase difference using the arrangement relationship of the different photodiodes PD included in each pixel PX. Such phase difference detection can be performed for each direction in which the photodiodes PD in the first to fourth pixels PX1, PX2, PX3, and PX4 are arranged. In the present embodiment, since the first to fourth pixels PX1, PX2, PX3, and PX4 are arranged in the first direction D1 and the second direction D2, phase differences in both the horizontal and vertical directions can be detected.

[0080] In this way, in one embodiment of the present invention, while the microlens ML senses an image, it is possible to detect a phase difference according to the position of light incident on the same lens, and autofocusing is possible using such phase difference.

[0081] In this embodiment, one pixel group PXG may include first to fourth pixels PX1, PX2, PX3, and PX4 arranged in a 2×2 matrix, but this is not limited to this and, although not shown, in other embodiments of the present invention, one pixel group PXG may include first to ninth semiconductor pixels arranged in a 3×3 matrix shape.

[0082] The image sensor according to an embodiment of the present invention may be modified into various shapes within the limits of the concept of the present invention. For the sake of simplicity, the following description will focus on differences from the above embodiment.

[0083] FIG. 6 is a plan view of an image sensor according to an embodiment of the present invention, corresponding to the second pixel group PXG2 of FIG. 4A, and FIG. 7 is a cross-sectional view taken along line A-A' of FIG.

[0084] 6 and 7, in the image sensor according to an embodiment of the present invention, a portion of the pixel separator 110 may be removed between two or more adjacent pixels PX, and the light path changing member LM may be spaced apart from the pixel separator 110 in a plan view. That is, the light path changing member LM may be disposed in an area where the pixel separator 110 has been removed in a plan view. In particular, since the first direction pixel separator 110 and the second direction pixel separator 110 provided between two adjacent pixels PX in one pixel group PXG intersect with each other, the pixel separator 110 in this embodiment is a case where at least a portion of a portion corresponding to the intersection area is removed, and the light path changing member LM is provided in the removed area.

[0085] The above structure corresponds to a configuration in which the first to fourth pixels PX1, PX2, PX3, and PX4 share a floating diffusion region. Here, the removed portions of the intersection regions may be entirely removed from the first surface 100a to the second surface 100b of the semiconductor substrate 100 along the third direction D3. A floating diffusion region shared by a plurality of unit pixels PX included in each pixel group PXG is formed in the removed portions of the intersection regions. In this configuration, electrons may move between two adjacent pixels PX through the removed portions of the intersection regions, which may be controlled by a potential barrier formed in the semiconductor substrate 100 according to the removed length and the manufacturing process.

[0086] In this embodiment, the light path changing member LM is provided in the intersection region, so that light can be effectively transmitted to a number of adjacent pixels PX, such as the first to fourth pixels PX1, PX2, PX3, and PX4 in this embodiment, and thus the light receiving efficiency of the photodiode PD can be maximized.

[0087] 8 to 11 are cross-sectional views showing an image sensor according to an embodiment of the present invention, taken along line AA' of FIG. 4A.

[0088] Referring to FIG. 8, according to one embodiment of the present invention, various materials may be used to fill the recessed portion of the light path changing member LM, and in particular, one of the color filters CF may be filled in the recessed portion of the light path changing member LM.

[0089] The refractive index of the color filter CF is different from that of the semiconductor substrate 100, and the light path can be easily changed due to the refraction effect of the incident light. Also, when the color filter CF is filled in the recess, the step of filling the recess with another insulating material can be omitted, and the image sensor can be easily manufactured. In addition, the light path is shortened, and the problem of reduced light transmittance when multiple layers are stacked is minimized.

[0090] 9, in an image sensor according to an embodiment of the present invention, the color filters CF may be formed only in the recesses of the light path changing member LM using the light path changing member LM, rather than being formed as a separate layer. That is, among the color filters CF, one color filter CF corresponding to a corresponding pixel PX may be filled only in the recesses, and a microlens ML may be disposed directly on the recesses.

[0091] At this time, the area of ​​the light path changing member LM on a plane can be changed in various ways. As shown in Fig. 9, at least a part of the color filter CF of a corresponding pixel PX can overlap with the microlens ML corresponding to the corresponding pixel PX group in a plan view. Here, if light is provided to the photodiode PD without passing through the color filter CF, the amount of light to the photodiode PD can be increased, so the amount of light incident on the photodiode PD can be controlled by adjusting the overlapping and non-overlapping portions of the color filter CF and the microlens ML.

[0092] In an embodiment of the present invention, the light path changing member LM may have various curved surfaces different from those of the above-described embodiment along the direction from the first surface 100a to the second surface 100b of the semiconductor substrate 100. The light path changing member LM according to an embodiment of the present invention may have various shapes within a limit that controls the refraction of light so that the light can be redistributed to the corresponding photodiode PD at a maximum without being absorbed by the pixel separating unit 110, etc.

[0093] 10, the light path changing member LM may have a protrusion protruding in a direction opposite to a direction from the first surface 100a toward the second surface 100b, i.e., in a third direction D3. In this embodiment, the inside of the protrusion may be filled with the same material as the semiconductor substrate 100. That is, the protrusion may be made of a semiconductor material, for example, a group IV semiconductor, like the semiconductor substrate 100. The group IV semiconductor may include silicon, germanium, or silicon-germanium, and the protrusion and the semiconductor substrate 100 may be formed integrally without being separated. In this embodiment, an interlayer film 150 covering the protrusion may be provided between the protrusion and the color filter CF.

[0094] 11, the light path changing member LM may have a curved surface having a shape protruding in a third direction D3 similar to that shown in FIG 10, and the inside of the protruding portion may be filled with the same material as the semiconductor substrate 100. However, unlike the embodiment shown in FIG 10, the interlayer film may be omitted, and a color filter CF may be provided on the semiconductor substrate 100. In one embodiment of the present invention, by omitting the interlayer film, the amount of light incident on the photodiode PD may be increased.

[0095] In an image sensor according to an embodiment of the present invention, the light path changing member LM may have a symmetrical shape as described above, but is not limited thereto and may be modified into various shapes.

[0096] FIG. 12A is a plan view showing an image sensor according to an embodiment of the present invention, corresponding to the second pixel group of FIG. 4A, and FIG. 12B is a cross-sectional view taken along line A-A' of FIG. 12A.

[0097] 12A and 12B, the shape of the light path changing member LM may be provided in a shape that is not circular but is line-symmetrical along a specific direction in a plan view. This is to allow light to travel equally to the pixels PX adjacent to the light path changing member LM, not to the pixel separators 110 arranged around the light path changing member LM, and the light path changing member LM may have a shape that is further protruded toward the corresponding photodiode PD. For example, as shown in the drawings, the light path changing member LM may be provided in a shape that is further protruded in a diagonal direction of the first to fourth pixels PX1, PX2, PX3, and PX4, i.e., a shape similar to a four-leaf clover, in a plan view. The light path changing member LM may also have a shape that is protruded toward the corresponding photodiode PD side when viewed in a cross section. That is, the light path changing member LM may have a shape that is line-symmetrical along the first direction D1 and the second direction D2 in a plan view, and may have a shape that is line-symmetrical along the third direction D3 when viewed in a cross section.

[0098] However, the shape of the light path changing member LM is described as an example and is not limited thereto. For example, the light path changing member LM may be provided asymmetrically according to the shapes and sizes of the pixels PX adjacent to each other. Alternatively, even if the corresponding pixels PX have the same size and shape, the light path changing member LM may be provided asymmetrically when the corresponding microlenses ML are provided asymmetrically.

[0099] FIG. 13 is a cross-sectional view taken along line AA' in a plan view corresponding to the second pixel group PXG2 of FIG. 4A, illustrating an image sensor according to an embodiment of the present invention.

[0100] 13, in an image sensor according to an embodiment of the present invention, at least one microlens ML may have an asymmetric shape. When the microlens ML has an asymmetric shape, the focal point may be formed at a position other than the pixel separator 110, and therefore, sufficient light may not be distributed to adjacent pixels PX. In this case, the light path changing member LM is formed asymmetrically corresponding to the focal point of the corresponding asymmetric microlens ML, so that the light path of the light passing through the asymmetric microlens ML can be effectively changed. In this embodiment, when the asymmetric microlens ML is used, it is advantageous to collect light incident in an inclined shape that is not perpendicular to the first surface 100a of the semiconductor substrate 100. Therefore, even if light is incident on the image sensor in an inclined shape at a certain angle, not only the light detection efficiency is increased, but also the phase difference detection efficiency of the light provided to adjacent pixels PX (i.e., the first to fourth pixels PX1, PX2, PX3, and PX4) is increased, and the autofocusing ability can be improved.

[0101] In one embodiment of the present invention, the light path changing member LM may be provided in different sizes depending on the shape and size of adjacent pixels PX or pixel groups PXG, or may be provided in different sizes taking into account characteristics depending on the color of the corresponding pixels PX.

[0102] 14A and 14B are plan views corresponding to the second pixel group PXG2 of FIG. 4A in an image sensor according to an embodiment of the present invention.

[0103] 14A and 14B, a light path changing member LM is provided in each of the first to fourth pixel groups PX1, PX2, PX3, and PX4. The light path changing members LM may be provided in different sizes depending on colors or areas.

[0104] For example, when the first to fourth pixels PX1, PX2, PX3, and PX4 are arranged in a 2×2 matrix, the second and third pixels PX2 and PX3 may have a larger microlens ML than the other pixels, or the pixels themselves may be expanded to have a larger area. At the same time, the first and / or fourth pixels PX1 and / or PX4 may have a smaller microlens ML than the second and third pixels PX2 and PX3, or may be reduced to have a smaller area. Here, the first pixel PX1 may correspond to blue as the first color filter CF1, the second pixel PX2 may correspond to green as the second color filter CF2, the third pixel PX3 may correspond to green as the second color filter CF2, and the fourth pixel PX4 may correspond to red as the third color filter CF3. Through such area change, the photodiode can more easily convert light of a specific color. In this case, the size and shape of the light path changing member LM may also be provided corresponding to each color filter CF, thereby improving light receiving efficiency.

[0105] In addition, the light traveling to the corresponding photodiode PD through the microlens ML and the color filter CF may generate chromatic aberration according to the color. Also, the light may have different absorptance to the semiconductor substrate 100. Therefore, the light path changing member LM may be formed in consideration of this. For example, the light passing through the microlens ML is focused at different positions for each color, and when the light path changing member LM is formed at the same position and with the same size, non-uniform light sensing may occur due to chromatic aberration according to the color. Also, the semiconductor substrate 100 on which the photodiode PD is formed has different light absorptance according to the color. In consideration of such color-specific characteristics, in the present embodiment, the light receiving efficiency may be maximized by providing the light path changing member LM having different sizes and shapes for each pixel group PXG corresponding to each color.

[0106] The image sensor according to an embodiment of the present invention having the above-mentioned structure can be manufactured by various methods. In the description of the present embodiment, the method of manufacturing the image sensor of the embodiment shown in Figures 5A, 8, 9, and 10 will be described as an example to avoid duplication of description. However, it is obvious that the method of manufacturing the image sensor according to an embodiment of the present invention can be modified in various forms within the concept of the present invention.

[0107] 15A to 15F are cross-sectional views sequentially illustrating a method for manufacturing the image sensor shown in FIG. 5A.

[0108] 15A, first, a semiconductor substrate 100 is provided on which a pixel electrode 120, a wiring structure 130, a photodiode PD, a pixel isolation portion 110, and an element isolation portion 107 are formed. To this end, a semiconductor substrate 100 is prepared, and some components of a pixel PX are formed on a second surface 100b of the semiconductor substrate 100. At this stage, the pixel electrode 120, an insulating film 140, and a wiring structure 130 are formed on the second surface 100b of the semiconductor substrate 100, and the pixel isolation portion 110 and the element isolation portion 107 are formed from the second surface 100b of the semiconductor substrate 100 toward the first surface 100a.

[0109] The pixel isolation portion 110 may be formed by forming a deep trench recessed from the first surface 100a and filling the deep trench with an insulating material or a conductive material. When the deep trench is filled with a conductive material, an insulating liner may be interposed between the conductive material and the semiconductor substrate 100. Then, a portion of the semiconductor substrate 100 on the first surface 100a side may be removed by chemical mechanical polishing until the pixel isolation portion 110 penetrates both sides of the semiconductor substrate 100. The device isolation portion 107 may be formed by forming a shallow trench and filling it with an insulating material.

[0110] 15B, in order to form the light path changing member LM at the center of one pixel group PXG, a part of the first surface 100a on the semiconductor substrate 100 is etched to form a recess. The wall surface of the recess is curved to form the light path changing member LM. At this time, the light path changing member LM is formed to overlap the area where the pixel separating portion 110 is formed.

[0111] Referring to FIG. 15C, an insulating material may be filled into the recess where a portion of the semiconductor substrate 100 is removed by etching.

[0112] Referring to FIG. 15D, a grid layer 160 is formed on the first surface 100a of the semiconductor substrate 100 filled with an insulating material.

[0113] 15E, a color filter CF is formed on the semiconductor substrate 100 on which the grid layer 160 is formed. The color filter CF may be formed corresponding to each pixel group PXG.

[0114] 15F, a microlens ML is formed on the semiconductor substrate 100 on which the color filter CF is formed. The microlens ML may be manufactured by first forming a planarization layer and then forming a microlens portion on the planarization layer in order to uniformly planarize the upper surface on which the color filter CF is formed. Here, the planarization layer and the microlens portion may be manufactured from different materials, or may be manufactured from the same material. In this case, the planarization layer and the microlens portion may be integrated without being separated.

[0115] 16A to 16C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor shown in FIG. 8, and steps that are substantially the same as those in the above-described embodiment are omitted.

[0116] To manufacture the image sensor shown in Fig. 8, first, a semiconductor substrate 100 having pixel electrodes 120, wiring structures 130, photodiodes PD, pixel isolation portions 110, and device isolation portions 107 formed thereon is formed as shown in Fig. 15A, and then a portion of a first surface 100a of the semiconductor substrate 100 is etched to form a recess in order to form a light path changing member LM at the center of one pixel group PXG as shown in Fig. 15B. The recess may be formed by etching the semiconductor substrate 100 in various shapes and sizes depending on the shape and size of the light path changing member LM to be formed.

[0117] Next, referring to FIG. 16A, a grid layer 160 is formed on the first surface 100a of the semiconductor substrate 100 filled with an insulating material.

[0118] 16B, a color filter CF is formed on the semiconductor substrate 100 on which the grid layer 160 is formed. The color filter CF may be formed corresponding to each pixel group PXG.

[0119] 16C, a microlens ML is formed on the semiconductor substrate 100 on which the color filter CF is formed. The microlens ML may be manufactured by first forming a planarization layer to uniformly planarize the upper surface on which the color filter CF is formed, and then forming a microlens portion on the planarization layer.

[0120] 17A to 17C are cross-sectional views sequentially illustrating a method for manufacturing the image sensor shown in FIG. 9, and steps that are substantially the same as those in the above-described embodiment are omitted.

[0121] To manufacture the image sensor shown in FIG. 9, first, as shown in FIG. 15A, a semiconductor substrate 100 having a pixel electrode 120, a wiring structure 130, a photodiode PD, a pixel isolation portion 110, and an element isolation portion formed thereon is formed.

[0122] 17A, a recess is formed by etching a portion of the first surface 100a of the semiconductor substrate 100 in order to form the light path changing member LM at the center of one pixel group PXG. The recess can be formed by etching the semiconductor substrate 100 into various shapes and sizes that reflect the shape and size of the light path changing member LM to be formed.

[0123] Referring to FIG. 17B, a color filter CF may be filled in a recess formed by etching a portion of the semiconductor substrate 100.

[0124] Referring to FIG. 17C, a microlens ML is formed on the semiconductor substrate 100 in which the color filter CF is filled in the recess.

[0125] 18A to 18G are cross-sectional views sequentially illustrating a method for manufacturing the image sensor shown in FIG.

[0126] 18A, a semiconductor substrate 100 is formed on which a pixel electrode 120, a wiring structure 130, a photodiode PD, a pixel isolation portion 110, and an element isolation portion are formed.

[0127] 18B, an additional layer 100' is formed on a semiconductor substrate 100 using the same material as the semiconductor substrate 100. The additional layer 100' corresponds to a layer for forming a light path changing member LM through subsequent patterning.

[0128] 18C, the additional layer 100′ is patterned to form the light path changing member LM. The light path changing member LM is manufactured by etching the upper surface of the additional layer 100′ on the semiconductor substrate 100 to form a protruding portion protruding in a third direction D3 above the semiconductor substrate 100.

[0129] Referring to FIG. 18D, an interlayer film 150 is formed on the semiconductor substrate 100 on which the optical path changing member LM is formed, to cover the optical path changing member LM.

[0130] Referring to FIG. 18E, a grid layer 160 is formed on the first surface 100a of the semiconductor substrate 100 on which the interlayer film 150 is formed.

[0131] 18F, a color filter CF is formed on the semiconductor substrate 100 on which the grid layer 160 is formed. The color filter CF may be formed corresponding to each pixel group PXG.

[0132] 18G, a microlens ML is formed on the semiconductor substrate 100 on which the color filter CF is formed. The microlens ML may be manufactured by first forming a planarization layer to uniformly planarize the upper surface on which the color filter CF is formed, and then forming a microlens portion on the planarization layer.

[0133] According to an embodiment of the present invention, an image sensor can be manufactured in a simple manner as described above.

[0134] The light path changing member LM according to an embodiment of the present invention can be applied to various pixel arrays PA different from the above-mentioned embodiments.

[0135] FIG. 19 is a drawing showing a pixel array PA including a plurality of pixel groups PXG according to another embodiment of the present invention, FIG. 20 is a plan view showing portion P2 in FIG. 19, and FIG. 21 is a cross-sectional view along line A-A' in FIG. 20.

[0136] 19 to 21, an image sensor according to an embodiment of the present invention includes a pixel array PA including a pixel PX. A plurality of pixel groups PXG may be provided in the pixel array PA. The pixel group PXG may include four pixels, ie, first to fourth pixels PX1, PX2, PX3, and PX4. One pixel group PXG may include first to fourth pixels PX1, PX2, PX3, and PX4 arranged in a 2×2 matrix. Here, the row direction is a first direction D1, the column direction is a second direction D2, and the first and second pixels PX1, PX2 and the third and fourth pixels PX3, PX4 are sequentially arranged along the first direction D1, with the first and second pixels PX1, PX2 forming a first row and the third and fourth pixels PX3, PX4 forming a second row.

[0137] The first to fourth pixels PX1, PX2, PX3, and PX4 may each include one photodiode PD, and the colors of the first to fourth pixels PX1, PX2, PX3, and PX4 may be realized by a color filter CF corresponding to each pixel PX. In this manner, the first to third color filters CF1, CF2, and CF3 may correspond to each pixel PX. According to an embodiment of the present invention, the first to third color filters CF1, CF2, and CF3 may respectively represent blue, green, and red colors, and blue may correspond to the first pixel PX1, green to the second pixel PX2, green to the third pixel PX3, and red to the fourth pixel PX4.

[0138] An optical path changing member LM is provided between the semiconductor substrate 100 and the color filter CF. The optical path changing member LM may have a curved surface that is concave or convex in a direction from the first surface 100a to the second surface 100b of the semiconductor substrate 100. For example, as illustrated, the optical path changing member LM may have a recess that is recessed in a direction from the first surface 100a to the second surface 100b. The recess may be filled with a material different from that of the semiconductor substrate 100 so as to have a refractive index different from that of the semiconductor substrate 100. For example, the recess may be filled with an insulating material different from that of the semiconductor substrate 100. The insulating material may be silicon oxide, silicon nitride, silicon oxynitride, various inorganic materials, and organic materials such as polyvinyl alcohol. The refractive index of light passing through the optical path changing member LM may be determined according to the selection of the insulating material.

[0139] Here, as shown in the plan view, the light path changing member LM may cover the entire first surface 100a region of the semiconductor substrate 100 except for the pixel separating unit 110, but is not limited thereto and may cover only a part of the first surface 100a region of the semiconductor substrate 100. Of course, the area and shape of the light path changing member LM may be set differently depending on the shape of the corresponding microlens ML according to the amount of light, incident angle, color, etc. of light incident on each semiconductor substrate 100.

[0140] 22 to 25 are cross-sectional views showing an image sensor according to an embodiment of the present invention, taken along line AA' of FIG. 20. FIG.

[0141] Referring to FIG. 22, according to an embodiment of the present invention, the recess of the light path changing member LM may be filled with any one of the color filters CF.

[0142] 23, the light path changing member LM may have a protrusion protruding in a direction opposite to a direction from the first surface 100a toward the second surface 100b, i.e., a third direction. In this embodiment, the inside of the protrusion may be filled with the same material as the semiconductor substrate 100. That is, the protrusion may be made of a semiconductor material, for example, a group IV semiconductor, like the semiconductor substrate 100. The group IV semiconductor may include silicon, germanium, or silicon-germanium, and the protrusion and the semiconductor substrate 100 may be formed integrally without being separated. In this embodiment, an interlayer film 150 covering the protrusion may be provided between the protrusion and the color filter CF.

[0143] 24, the light path changing member LM may have a curved surface having a shape protruding in a third direction similar to that shown in Fig. 10, and the inside of the protruding portion may be filled with the same material as the semiconductor substrate 100. However, unlike the embodiment shown in Fig. 19, the interlayer film may be omitted, and a color filter CF may be provided on the semiconductor substrate 100.

[0144] 25, in an image sensor according to an embodiment of the present invention, the color filters CF may be formed only in the recesses of the light path changing member LM using the light path changing member LM, rather than being formed as a separate layer. That is, among the color filters CF, one color filter CF corresponding to a corresponding pixel PX may be filled only in the recesses, and a microlens ML may be disposed directly on the recesses.

[0145] The light path changing member LM according to an embodiment of the present invention can be applied to the above-mentioned embodiments and various other pixel arrays.

[0146] FIG. 26A shows a pixel array PA according to another embodiment of the present invention, and FIG. 26B is a plan view showing a portion P3 in FIG. 26A.

[0147] 26A and 26B, an image sensor according to an embodiment of the present invention includes a pixel array PA including a pixel PX. A plurality of pixel groups PXG may be provided in the pixel array PA. The pixel group PXG may include four pixels, ie, first to fourth pixels PX1, PX2, PX3, and PX4. One pixel group PXG may include first to fourth pixels PX1, PX2, PX3, and PX4 arranged in a 2×2 matrix. Here, the first to fourth pixels PX1, PX2, PX3, and PX4 are provided with their own microlenses ML. That is, the first to fourth pixels PX1, PX2, PX3, and PX4 do not share the same microlenses ML.

[0148] Each pixel PX may include a first sub-pixel SPX1 and a second sub-pixel SPX2 that share one microlens ML. In the image sensor according to the present embodiment, the first sub-pixel SPX1 and the second sub-pixel SPX2 can sense a phase difference of light incident through one microlens ML as well as obtain an image signal, so that autofocusing is possible.

[0149] In this embodiment, the light path changing member LM is provided in a one-to-one correspondence with each of the first to fourth pixels PX1, PX2, PX3, and PX4, and is provided between two adjacent sub-pixels PX. In this embodiment, the pixel separators 110 may have a shape that extends in only one direction (for example, the second direction as illustrated) instead of a cross shape that intersects with each other. A pixel separator 110 may be provided between two adjacent sub-pixels PX, and the light path changing member LM may prevent light from traveling to the pixel separator 110 between the two sub-pixels PX and refract light so that the light travels to the two sub-pixels PX.

[0150] FIG. 27A shows a pixel array PA according to another embodiment of the present invention, and FIG. 27B is a plan view showing a portion P4 in FIG. 27A.

[0151] 27A and 27B, an image sensor according to an embodiment of the present invention includes a pixel array PA including pixels PX. A plurality of pixel groups PXG may be provided in the pixel array PA. The pixel group PXG may include two pixel groups, i.e., first and second pixels PX1 and PX2. Here, the first and second pixels PX are provided with one microlens ML, and therefore the first and second pixels PX share one microlens ML.

[0152] The image sensor according to this embodiment not only obtains image signals from two adjacent pixels PX, but also enables autofocusing because the first pixel PX and the second pixel PX can sense the phase difference of light incident through one microlens ML.

[0153] In this embodiment, the shape of the microlens ML does not have to be circular depending on the arrangement of the first pixel PX and the second pixel PX. For example, the shape of the microlens ML may be elliptical as shown in the figure. In this embodiment, the light path changing member LM may also be changed to various shapes, for example, an elliptical shape, depending on the shape of the microlens ML and the position of the focal point, etc.

[0154] In the above-described embodiment, for ease of explanation, pixels PX and / or pixel groups PXG of the same shape are provided in the pixel array PA, but the arrangement of the pixel array PA is not limited to this.

[0155] FIG. 28 shows a pixel array PA according to another embodiment of the present invention.

[0156] 28, the pixel array PA may include two or more pixel groups PXG having different shapes. For example, the pixel array PA may include first and second pixel groups PXG1 and PXG2 that are different from each other. The second pixel group PXG2 may include first to fourth pixels PX1, PX2, PX3, and PX4, and a microlens ML may be provided for each of the first to fourth pixels PX1, PX2, PX3, and PX4. The second pixel group PXG2 may include first to fourth pixels PX1, PX2, PX3, and PX4, and the first to fourth pixels PX1, PX2, PX3, and PX4 may share one microlens ML. Here, each pixel PX of the first pixel group PXG1 may include a first sub-pixel SPX1 and a second sub-pixel SPX2.

[0157] In addition, the pixel array PA may further include another color filter CF, for example a color filter W indicating white, in addition to the first to third color filters CF1, CF2, and CF3, so that each pixel PX of the first pixel group PXG1 is provided with one color filter CF among the first to third color filters CF1, CF2, and CF3, and each pixel PX of the second pixel group PXG2 is provided with a color filter W indicating white.

[0158] In the pixel array PA having different pixel groups PXG, the light-path changing member LM may be provided in various shapes according to each pixel PX and / or each pixel group PXG.

[0159] In the above embodiment, for ease of explanation, the pixels and / or pixel groups have been described as having a rectangular shape, but the shape of the pixels and / or pixel groups is not limited thereto. That is, according to an embodiment of the present invention, the shape of each pixel and / or pixel group may be changed in various ways, for example, each pixel and / or pixel group may have a hexagonal honeycomb shape, some pixels and / or pixel groups may be square, and the remaining pixels and / or pixel groups may be octagonal.

[0160] In addition, in the above-mentioned embodiments, as long as they are not mutually exclusive, it is of course possible to combine them into various shapes. For example, in the above-mentioned embodiments, all pixels have the first and second sub-pixels, but only some pixels in the pixel array may have the first and second sub-pixels, and other pixels may be formed of only one pixel without sub-pixels. In addition, in the above-mentioned embodiments, 2×2 pixels are illustrated as forming one pixel group, but this is not limited thereto, and it is of course possible to combine them into various shapes, such as 3×3 pixels forming one pixel group, some 2×2 pixels forming one pixel group, other 1×2 pixels forming one pixel group, and other 2×1 pixels forming one pixel group.

[0161] Although the present invention has been described above with reference to preferred embodiments, it will be understood that a person skilled in the art or having ordinary knowledge in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention as described in the claims below.

[0162] Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims. [Explanation of symbols]

[0163] 100 Semiconductor substrate PX Pixels SPX Subpixel PXG Pixel Group PD Photodiode CF Color Filter ML Micro Lens LM Optical Path Change

Claims

1. An image sensor including a plurality of pixels arranged in a matrix, a photodiode provided for each pixel in a semiconductor substrate having a first surface to which light is incident and a second surface opposite to the first surface; a microlens provided on the first surface of the semiconductor substrate to focus the light; a color filter provided between the semiconductor substrate and the microlens; a light path changing member that changes a path of at least a portion of the light when the light travels through the microlens toward the photodiode; The optical path changing member extends from the first surface of the semiconductor substrate and has a curved surface that is concave or convex along a direction toward the second surface.

2. 2. The image sensor of claim 1, wherein at least two pixels among the plurality of pixels share one microlens among the microlenses, and the light path changing member is provided at a center of the at least two pixels in a plan view.

3. The image sensor according to claim 2 , wherein the optical path changing member has a curved surface that is recessed or bulged along a direction from the first surface of the semiconductor substrate toward the second surface of the semiconductor substrate.

4. The image sensor of claim 3 , wherein the optical path changing member has a recess that is recessed in a direction from the first surface to the second surface.

5. The image sensor of claim 4 , wherein the recess comprises an insulating material.

6. The image sensor of claim 5 , wherein the recess includes one of the color filters.

7. The image sensor of claim 6 , wherein any one of the color filters is filled only in the recess.

8. The image sensor of claim 3 , wherein the optical path changing member has a protrusion protruding in a direction opposite to a direction from the first surface of the semiconductor substrate toward the second surface of the semiconductor substrate.

9. The image sensor of claim 8 , wherein the protrusion comprises the same material as the semiconductor substrate.

10. The image sensor of claim 9 , further comprising an interlayer film provided between the protrusion and the color filter.

11. The image sensor according to claim 2 , further comprising a pixel separator provided in the semiconductor substrate and partitioning the pixels, wherein the light path changing member overlaps with the pixel separator in a plan view.

12. The image sensor according to claim 11 , wherein, in a plan view, a portion of the pixel separating portion is removed, and the light path changing member is disposed in a region where the pixel separating portion has been removed.

13. The image sensor of claim 2 , wherein the plurality of pixels includes a plurality of pixel groups including first to fourth pixels arranged in a 2×2 matrix.

14. 3. The image sensor of claim 2, wherein the plurality of pixel groups includes first through fourth pixel groups arranged in a 2x2 matrix, the first through fourth pixel groups including blue, green, red and red filters, respectively.

15. 3. The image sensor of claim 2, wherein the plurality of pixel groups include first to fourth pixel groups arranged in a 2x1 matrix, the first to fourth pixel groups including a blue filter, a first green filter, a second green filter, and a red filter, respectively.

16. The image sensor according to claim 1 , wherein the optical path changing member overlaps a focal point of the microlens in a plan view.

17. The image sensor of claim 1 , wherein materials disposed on both sides of the curved surface of the light path changing member have different refractive indices.

18. The image sensor includes a plurality of pixel groups each having one of first to third colors, and each pixel group is made up of first to fourth pixels arranged in a 2×2 matrix shape, photodiodes provided in the first to fourth pixels in a semiconductor substrate having a first surface to which light is incident and a second surface opposite to the first surface; microlenses provided on the first surface of the semiconductor substrate corresponding to the first to fourth pixels to condense the light; a color filter provided between the semiconductor substrate and the microlens; a light path changing member that changes a path of at least a portion of the light when the light travels through the microlens toward the photodiode; The optical path changing member extends from the first surface of the semiconductor substrate and has a curved surface that is concave or convex along a direction toward the second surface of the semiconductor substrate.

19. 20. The image sensor of claim 18, wherein the light path changing member overlaps with a focal point of the microlens in a planar view, and materials disposed on both sides of the curved surface of the light path changing member have refractive indices different from each other.

20. providing a semiconductor substrate having a photodiode and a pixel separator formed thereon, the semiconductor substrate having a first surface and a second surface opposite the first surface; forming a light path changing member on a first surface of the semiconductor substrate in a region overlapping with the pixel separating portion in a plan view; forming a color filter on the semiconductor substrate on which the optical path changing member is formed; forming a microlens on the semiconductor substrate on which the color filter is formed; The method for manufacturing an image sensor, wherein the optical path changing member extends from the first surface of the semiconductor substrate and has a curved surface that is concave or convex along a direction toward the second surface of the semiconductor substrate.

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