Image sensor including phase detection pixels

Abstract

To provide an image sensor including a phase detection pixel.SOLUTION: An image sensor includes a pixel array. The pixel array includes: a plurality of image sensing pixels formed in a substrate; a phase detection sharing pixel formed in the substrate and including two phase detection sub-pixels that are arranged side by side; a color filter fence disposed on the image sensing pixels and the phase detection sharing pixel and including a plurality of color filter spaces; a plurality of color filter layers disposed in the respective color filter spaces on the image sensing pixels and the phase detection sharing pixel; a first microlens disposed on each of the image sensing pixels and having a first height; and a second microlens disposed overlapping vertically with the two phase detection sub-pixels on the phase detection sharing pixel and having a second height larger than the first height.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to image sensors, and more particularly to image sensors that include phase detection pixels. [Background technology]

[0002] Image sensors are devices used to capture light information and convert it into electrical signals to generate an image. Image sensors are found in a variety of devices. For example, they are used in cameras, phones, medical imaging devices, thermal imaging devices, and night vision devices.

[0003] In some cases, the image sensor includes image sensing pixels that receive incident light and convert it into an electrical signal. The image sensor also includes multiple photodiode regions, where an autofocus function can be performed to allow image capture to be performed accurately in a short time.

[0004] A microlens is a small lens located on an image sensing pixel. The microlens is also used to provide good optical properties to the image sensor. The microlenses on the image sensing pixels are manufactured at the same time, e.g., even during the same manufacturing process. However, the simultaneous manufacturing of the microlenses induces lenses that cannot be optimized. For example, all the lenses manufactured are also uniform. The optimization of the microlenses for the other image sensing pixels is also provided for improved optical properties for the image sensor. Therefore, a manufacturing process capable of manufacturing other microlenses for other image sensing pixels of the image sensor is required. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an image sensor capable of quickly and accurately performing an autofocus function while improving the sensitivity of an image sensing pixel. [Means for solving the problem]

[0006] An image sensor according to the technical idea of ​​the present invention to achieve the above technical problem includes a pixel array, the pixel array including a plurality of image sensing pixels formed in a substrate, a phase detection shared pixel formed in the substrate and including two phase detection sub-pixels arranged side by side, a color filter fence arranged on the plurality of image sensing pixels and the phase detection shared pixel and including a plurality of color filter spaces, a plurality of color filter layers arranged in the plurality of color filter spaces over the plurality of image sensing pixels and the phase detection shared pixel, respectively, a first microlens arranged on each of the plurality of image sensing pixels and having a first height, and a second microlens arranged on the phase detection shared pixel to be vertically overlapped with the two phase detection sub-pixels and having a second height higher than the first height.

[0007] An image sensor according to the technical idea of ​​the present invention to achieve the above technical problem includes a pixel array, the pixel array including a plurality of image sensing shared pixels each including a plurality of image sensing sub-pixels corresponding to a color filter layer of the same hue, a plurality of phase detection shared pixels including two phase detection sub-pixels generating a phase signal for calculating a phase difference between respective images, and a microlens structure arranged on the plurality of image sensing shared pixels and the plurality of phase detection shared pixels, the microlens structure including a first microlens arranged on each of the plurality of image sensing sub-pixels and having a first height, and a second microlens arranged on the two phase detection sub-pixels and having a second height higher than the first height.

[0008] The image sensor according to the technical idea of ​​the present invention for achieving the technical object includes a pixel array, the pixel array including a plurality of image sensing pixels formed in a substrate, a phase detection shared pixel formed in the substrate, generating a phase signal for calculating a phase difference between respective images, the phase detection shared pixel including two phase detection sub-pixels arranged side by side in a first direction parallel to an upper surface of the substrate, a pixel isolation film structure penetrating the substrate and arranged between the plurality of image sensing pixels, between the two phase detection sub-pixels, and between the phase detection shared pixel and an image sensing pixel adjacent thereto, and a pixel isolation film structure interposed between the plurality of image sensing pixels and the phase detection shared pixel. a color filter fence disposed over the output shared pixels and the phase detection shared pixel, the color filter fence including a plurality of color filter spaces; a plurality of color filter layers disposed over the plurality of image sensing pixels and the phase detection shared pixel, respectively, in the plurality of color filter spaces; a first microlens disposed over each of the plurality of image sensing pixels and having a first height; and a second microlens disposed over the two phase detection sub-pixels and having a second height higher than the first height, wherein a center line of the second microlens along the first direction vertically overlaps with a portion of the pixel isolation film structure disposed between the two phase detection sub-pixels.

[0009] To achieve the above technical objective, a manufacturing method for an image sensor according to the technical idea of ​​the present invention includes the steps of providing a plurality of pixels on a substrate, the plurality of pixels including one or more first pixels and one or more second pixels, providing a first microlens over each of the one or more first pixels using a first process, and providing a second microlens over each of the one or more second pixels using a second process, wherein the first microlens has a different shape from the second microlens. Effect of the Invention

[0010] According to the technical idea of ​​the present invention, a first microlens on an image sensing pixel and a second microlens on a phase detection shared pixel may have different heights, and the curvatures of the microlenses may be optimized in the image sensing pixel and the phase detection shared pixel, respectively. In addition, a color filter fence portion on the phase detection shared pixel may be wider than a color filter fence portion on the image sensing pixel, thereby improving the separation ratio characteristic of the phase detection shared pixel. The image sensor may quickly and accurately perform an autofocusing function, while improving the sensitivity of the image sensing pixel. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram that illustrates a schematic of an image processing apparatus according to an exemplary embodiment. [Diagram 2] FIG. 1 is a block diagram that illustrates a schematic representation of an image sensor in accordance with an exemplary embodiment. [Diagram 3] FIG. 2 is a layout diagram illustrating an image sensor according to an example embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along the line A1-A1' in FIG. [Diagram 5] 3 is a horizontal cross-sectional view taken along the first level LV1 of FIG. 4; [Figure 6] FIG. 4 is a plan view of a portion CX1 in FIG. [Figure 7] 2 is an equivalent circuit diagram of multiple pixels of an image sensor according to an example embodiment. [Figure 8] 1 illustrates a cross-sectional view of an image sensor according to an exemplary embodiment. [Figure 9] FIG. 4 is a horizontal cross-sectional view of a portion corresponding to CX1 in FIG. [Figure 10] 1 illustrates a cross-sectional view of an image sensor according to an exemplary embodiment. [Figure 11] 1 illustrates a cross-sectional view of an image sensor according to an exemplary embodiment. [Figure 12]FIG. 2 is a layout diagram illustrating an image sensor according to an example embodiment. [Figure 13] FIG. 13 is a horizontal cross-sectional view of a portion CX2 in FIG. [Figure 14] FIG. 2 is a layout diagram illustrating an image sensor according to an example embodiment. [Figure 15] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 16] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 17] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 18] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 19] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 20] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 21] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 22] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 23] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 24] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 25] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 26] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 27] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 28] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 29]1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 30] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 31] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 32] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 33] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 34] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 35] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 36] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 37] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 38] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Figure 39] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. [Diagram 40] 1A to 1C are cross-sectional views illustrating a method for manufacturing an image sensor according to an exemplary embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present disclosure generally relates to a microlens for an image sensing pixel in an image sensor. A common method is to form microlenses for other pixels during the same manufacturing process. For example, the process can simultaneously manufacture a microlens for a first pixel and a microlens for a second pixel based on the same manufacturing conditions. Thus, the height of the first microlens for the first pixel is also the same as the height of the second microlens for the second pixel. However, the curvature of the first microlens and the curvature of the second microlens are not optimized. As a result, the separation ratio characteristics, sensitivity, and signal-to-noise (SNR) characteristics of the first pixel and the second pixel are not optimized.

[0013] Therefore, the embodiments of the present disclosure describe a process for manufacturing other microlenses for other pixels in an image sensor. For example, a first microlens for a first pixel and a second microlens for a second pixel are formed through different processes. Thus, the curvature of the first microlens and the curvature of the second microlens are optimized, thereby improving pixel characteristics. Furthermore, the grid size of the first pixel and the grid size of the microlens for the second pixel are set independently. Thus, the separation ratio characteristic for the first pixel can be improved.

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0015] FIG. 1 is a block diagram that illustrates a schematic of an image processing device 1000 according to an exemplary embodiment.

[0016] 1, the image processing device 1000 is also a digital imaging device that performs an auto-focusing (AF) function. The image processing device 1000 may include an imaging unit 1100, an image sensor 100, and a processor 1200. The image processing device 1000 may be provided with a focus detection function for the auto-focusing function.

[0017] The imaging unit 1100 may include a lens 1110 , a lens driving unit 1120 , an aperture 1130 , and an aperture driving unit 1140 .

[0018] The lens driver 1120 can communicate information related to focus detection with the processor 1200, and can adjust the position of the lens 1110 based on a control signal provided by the processor 1200. This adjusts the distance between the lens 1110 and the object 2000, and the lens 1110 may or may not be in focus on the object 2000 depending on the position of the lens 1110. For example, when the distance between the lens 1110 and the object 2000 is relatively short, the lens 1110 moves out of an in-focus position for focusing on the object 2000, and a phase difference occurs between images captured by the image sensor 100. In such a case, the lens driver 1120 can move the lens 1110 in a direction in which the distance from the object 2000 increases based on the control signal provided by the processor 1200.

[0019] The image sensor 100 can convert incident light into an image signal. The image sensor 100 may include a pixel array PXA, a control unit 210, and a signal processing unit 220. An optical signal passing through a lens 1110 and an aperture 1130 reaches a light receiving surface of the pixel array PXA, and an image of an object 2000 can be formed. The pixel array PXA includes a plurality of pixels PX, as described in FIG. 2, and the plurality of pixels PX may include a plurality of image sensing pixels IPX and a plurality of phase detection pixels PPX.

[0020] The processor 1200 may receive pixel information from the signal processor 220 and perform a phase difference calculation, which may be performed by performing a correlation calculation of column signals of a plurality of pixels. The processor 1200 may obtain a focus position, a focus direction, or a distance between the object 2000 and the image sensor 100, as a result of the phase difference calculation. The processor 1200 may output a control signal to the lens driver 1120 to move the position of the lens 1110 based on the phase difference calculation result.

[0021] FIG. 2 is a block diagram that illustrates a schematic of an image sensor 100 in accordance with an example embodiment.

[0022] 2, the image sensor 100 may include a pixel array PXA, a control unit 210, a signal processing unit 220, a row driver 230, and a signal reading unit 240.

[0023] The pixel array PXA may be formed in pixel units and may include a plurality of pixels PX. Each of the plurality of pixels PX may include a corresponding photoelectric conversion region, for example, a photodiode. The plurality of pixels PX absorb light to generate electric charges, and an electric signal (output voltage) based on the generated electric charges is also provided to the signal reading unit 240.

[0024] The pixel array PXA may include a plurality of image sensing pixels IPX and a plurality of phase detection pixels PPX. The plurality of image sensing pixels IPX can generate an image signal corresponding to the object 2000 (FIG. 1). The plurality of phase detection pixels PPX can generate a phase signal that is used to calculate a phase difference between images.

[0025] The multiple phase detection pixels PPX included in the image sensor 100 are also used to focus on an object. The phase signal may include information related to the position of the images focused on the image sensor 100. Thus, the phase signal is also used to calculate a phase difference between the images. Based on the calculated phase difference, the focus position of the lens 1110 (FIG. 1) can be calculated. For example, the position of the lens 1110 that makes the phase difference zero is also the focus position.

[0026] In an exemplary embodiment, the multiple phase detection pixels PPX are used not only for focusing on the object, but also for measuring the distance between the object 2000 and the image sensor 100. To measure the distance between the object 2000 and the image sensor 100, additional information such as the phase difference between the images focused on the image sensor 100, the distance between the lens 1110 and the image sensor 100, the size of the lens 1110, and the focus position of the lens 1110 may be referenced.

[0027] The control unit 210 can control the row driver 230 to absorb light and accumulate charges using the pixel array PXA, temporarily store the accumulated charges, and output an electrical signal based on the stored charges to the outside of the pixel array PXA. The control unit 210 can also control the signal reading unit 240 to measure an output voltage provided by the pixel array PXA.

[0028] The row driver 230 may generate signals RSs, TXs, and SELSs for controlling the pixel array PXA and provide the signals to the pixels PX included in the pixel array PXA. The row driver 230 may determine activation and deactivation timings of the reset control signal RSs, the transmission control signal TXs, and the selection signal SELSs for the phase detection pixels PPX based on whether or not the AF function is performed.

[0029] The signal reading unit 240 may include a correlated double sampler (CDS) 242, an analog-to-digital converter (ADC) 244, and a buffer 246. The correlated double sampler 242 may sample and hold an output voltage provided by the pixel array PXA. The correlated double sampler 242 may double sample a specific noise level and a level according to the generated output voltage, and output a level corresponding to the difference. The correlated double sampler 242 may also receive a ramp signal generated by a ramp signal generator 248, compare the ramp signals with each other, and output a comparison result. The analog-to-digital converter 244 may convert an analog signal corresponding to a level received from the correlated double sampler 242 into a digital signal. The buffer 246 latches the digital signal, and the latched signal is sequentially output to the signal processing unit 220 or to the outside of the image sensor 100.

[0030] The signal processing unit 220 can perform signal processing on the data of the plurality of pixels PX received. The signal processing unit 220 can perform noise reduction processing, gain adjustment, waveform stylization processing, interpolation processing, white balance processing, gamma processing, edge enhancement processing, and the like. Furthermore, the signal processing unit 220 is configured to output the plurality of pixel PX information to the processor 1200 during phase difference AF and perform phase difference calculation. For example, the plurality of pixels PX can also be obtained during phase difference AF drive.

[0031] Fig. 3 is a layout diagram showing an image sensor 100 according to an exemplary embodiment. Fig. 4 is a cross-sectional view taken along line A1-A1 in Fig. 3. Fig. 5 is a horizontal cross-sectional view of the CX1 portion of Fig. 3 cut at the first level LV1 in Fig. 4, and Fig. 6 is a plan view of the CX1 portion of Fig. 3.

[0032] Referring to FIG. 3, the image sensor 100 includes a pixel array PXA, which may include a plurality of image sensing pixels IPX and a plurality of phase detection shared pixels PPX.

[0033] The plurality of image sensing pixels IPX are also arranged in a first direction (X direction) and a second direction (Y direction) parallel to the first surface 110F1 of the substrate 110. Here, the first direction is the column direction of the pixel array PXA, and the second direction is the row direction of the pixel array PXA. The plurality of phase detection shared pixels PPX may include a first phase detection sub-pixel PPXa and a second phase detection sub-pixel PPXb arranged adjacent to each other in the first direction (X direction). The plurality of phase detection shared pixels PPX are also arranged at a predetermined interval between the plurality of image sensing pixels IPX, for example, at a density of 1 / 16, 1 / 32, or 1 / 64 of the total number of pixels PX. For example, as shown in FIG. 3, when the pixel array PXA is configured to have 16 pixels PX in a first direction (X direction) and 16 pixels PX in a second direction (Y direction), the multiple phase detection shared pixels PPX can occupy 8 pixels PX and are also arranged at a density of 1 / 32.

[0034] As illustrated by way of example in FIG. 4, a plurality of image sensing pixels IPX and a plurality of phase detection shared pixels PPX may be arranged in a substrate 110, spaced apart from each other by a pixel isolation film structure 150, and a photoelectric conversion region 120 may be arranged within each of the plurality of image sensing pixels IPX and the plurality of phase detection shared pixels PPX.

[0035] The substrate 110 may include a first surface 110F1 and a second surface 110F2. Herein, the surface of the substrate 110 on which the microlens structure 180 is disposed is referred to as the second surface 110F2, and the surface opposite to the second surface 110F2 is referred to as the first surface 110F1. In an exemplary embodiment, the semiconductor substrate 110 may include a P-type semiconductor substrate. For example, the semiconductor substrate 110 may also be a P-type silicon substrate. In an exemplary embodiment, the semiconductor substrate 110 may include a P-type bulk substrate and a P-type or N-type epitaxial layer grown thereon. In another embodiment, the semiconductor substrate 110 may include an N-type bulk substrate and a P-type or N-type epitaxial layer grown thereon. Alternatively, the semiconductor substrate 110 may be an organic plastic substrate. The photoelectric conversion region 120 may include a photodiode region (not shown) and a well region (not shown) formed inside the substrate 110.

[0036] Although not shown in FIG. 4, an isolation layer (not shown) defining an active region (not shown) and a floating diffusion region FD (FIG. 7) may be further formed on the first surface 110F1 of the substrate 110.

[0037] A front side structure 130 may be disposed on the first surface 110F1 of the substrate 110. The front side structure 130 may include a gate electrode 132, a wiring layer 134, and an insulating layer 136.

[0038] The gate electrode 132 may be disposed on the first surface 110F1 of the substrate 110 and may constitute a plurality of transistors. For example, the plurality of transistors may include a transmission transistor TX configured to transmit charges generated in the photoelectric conversion region 120 to the floating diffusion region FD, a reset transistor RX configured to periodically reset the charges stored in the floating diffusion region FD, a drive transistor DX configured to act as a source follower buffer amplifier and buffer a signal according to the charges stored in the floating diffusion region, and a selection transistor SX configured to perform switching and addressing for selecting a plurality of image sensing pixels IPX. However, the plurality of transistors are not limited thereto.

[0039] FIG. 4 exemplarily illustrates the gate electrodes 132 as being formed in a flat plate shape on the first surface 110F1 of the substrate 110, but some of the gate electrodes 132 may also be formed as a recessed gate type extending from the first surface 110F1 of the substrate 110 into the substrate 110.

[0040] The wiring layer 134 is electrically connected to the gate electrode 132 or the active region. The wiring layer 134 may include tungsten, aluminum, copper, tungsten silicide, titanium silicide, tungsten nitride, titanium nitride, doped polysilicon, etc. An insulating layer 136 may cover the wiring layer 134 on the first surface 110F1 of the substrate 110 and may include an insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

[0041] Optionally, a support substrate 140 may be disposed on the front structure 130. An adhesive member (not shown) may be further disposed between the support substrate 140 and the front structure 130.

[0042] The pixel isolation film structure 150 is disposed to penetrate the substrate 110, and can physically and electrically isolate one image sensing pixel IPX from an adjacent image sensing pixel IPX. In a plan view, the pixel isolation film structure 150 may be disposed in a mesh or grid shape. As shown in FIG. 4, the pixel isolation film structure 150 extends from the first surface 110F1 to the second surface 110F2 of the substrate 110, and the width at the same level as the first surface 110F1 of the substrate 110 may be wider than the width at the same level as the second surface 110F2 of the substrate 110, but is not limited thereto.

[0043] The pixel isolation film structure 150 includes a conductive layer 152 and an insulating liner 154, and the insulating liner 154 may be interposed between the conductive layer 152 and the substrate 110. In an exemplary embodiment, the conductive layer 152 may include a conductive material such as polysilicon or a metal. The insulating liner 154 may include a metal oxide such as hafnium oxide, aluminum oxide, or tantalum oxide, in which case the insulating liner 154 may act as a negative fixed charge layer. In other embodiments, the insulating liner 154 may include an insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

[0044] A color filter fence 160 may be disposed on the second surface 110F2 of the substrate 110. As exemplarily illustrated in Fig. 5, the color filter fence 160 may have a grid or mesh shape in a planar view, and the color filter fence 160 is also disposed to vertically overlap the pixel isolation film structure 150. The color filter fence 160 may define a plurality of color filter spaces 160S in which a color filter layer 170 is disposed.

[0045] The color filter spaces 160S may include a first color filter space 160S1 arranged at a position overlapping with the image sensing pixels IPX, and a second color filter space 160S2 arranged at a position overlapping with the phase detection shared pixels PPX. A color filter layer 170 corresponding to the image sensing pixels IPX may be arranged in the first color filter space 160S1, and a color filter layer 170 corresponding to the phase detection shared pixels PPX may be arranged in the second color filter space 160S2. The second color filter space 160S2 is also arranged to overlap with both the first phase detection sub-pixel PPXa and the second phase detection sub-pixel PPXb in the vertical direction, and the second color filter space 160S2 may have a larger planar area than the first color filter space 160S1 in a top view.

[0046] The color filter fence 160 may include a barrier metal pattern 162 and a low refractive index material layer pattern 164 disposed on the barrier metal pattern 162. For example, the low refractive index material layer pattern 164 may have a first refractive index greater than about 1.0 and less than or equal to about 1.4. In an exemplary embodiment, the low refractive index material layer pattern 164 may include at least one of polymethyl methacrylate (PMMA), silicone acrylate, cellulose acetate butyrate (CAB), silica, and fluorosilicone acrylate (FSA). For example, the low refractive index material layer pattern 164 may include silica (SiO x ) The particles may comprise a dispersed polymeric material.

[0047] Since the low refractive index material layer pattern 164 has a relatively low first refractive index, light incident on the color filter fence 160 is totally reflected and directed toward the center of the plurality of image sensing pixels IPX. The color filter fence 160 can prevent light incident with an inclination angle into the color filter layer 170 disposed on one image sensing pixel IPX from entering the color filter layer 170 disposed on an adjacent image sensing pixel IPX, thereby preventing interference between the plurality of image sensing pixels IPX.

[0048] The color filter fence 160 may include a first fence portion 160I and a second fence portion 160P. The first fence portion 160I vertically overlaps a boundary between the plurality of image sensing pixels IPX (e.g., a portion of the pixel isolation film structure 150 between the plurality of image sensing pixels IPX), and the second fence portion 160P vertically overlaps a boundary between one of the plurality of phase detection sharing pixels PPX and an image sensing pixel IPX adjacent to the one of the phase detection sharing pixels PPX in the first direction (X direction). For example, the first color filter space 160S1 is also defined by the first fence portion 160I (or, in the plan view, the first color filter space 160S1 is also surrounded by the first fence portion 160I), and the second color filter space 160S2 is also defined by the first fence portion 160I and the second fence portion 160P (or, in the plan view, the second color filter space 160S2 is also surrounded by the first fence portion 160I and the second fence portion 160P).

[0049] The first fence portion 160I may have a first width w11 along the first direction (X direction), and the second fence portion 160P may have a second width w12 along the first direction (X direction) that is wider than the first width w11. The second width w12 of the second fence portion 160P may be 1.5 to 10 times the first width w11, but is not limited thereto. By forming the second fence portion 160P to be relatively wide, the separation ratio characteristic of the phase differences of the multiple phase detection shared pixels PPX may be improved.

[0050] Optionally, a backside insulating layer 166 is disposed between the second surface 110F2 of the substrate 110 and the color filter fence 160, and a passivation layer 168 is also conformally disposed on the top and sides of the color filter fence 160. The backside insulating layer 166 may include an insulating material such as a metal oxide, such as hafnium oxide, aluminum oxide, or tantalum oxide; silicon oxide, silicon nitride, silicon oxynitride, or a low-k material. The passivation layer 168 may include an insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or a low-k material.

[0051] A color filter layer 170 filling the color filter space 160S may be disposed on the color filter fence 160 and the passivation layer 168. The color filter layer 170 may sense green light, blue light, or red light depending on the type of material contained in the color filter layer 170. For convenience, the color filter layer 170 sensing green is referred to as a green color filter layer G, the color filter layer 170 sensing blue is referred to as a blue color filter layer B, and the color filter layer 170 sensing red is referred to as a red color filter layer R.

[0052] A microlens structure 180 may be disposed on the color filter fence 160 and the color filter layer 170. A capping layer 190 may be disposed on the microlens structure 180.

[0053] The microlens structure 180 may include a first microlens 182 and a second microlens 184. The first microlens 182 is also disposed over a plurality of image sensing pixels IPX, and the second microlens 184 is also disposed over a plurality of phase detection shared pixels PPX. For example, the second microlens 184 is also disposed to vertically overlap both the first phase detection sub-pixel PPXa and the second phase detection sub-pixel PPXb disposed side by side in the first direction (X direction), and thus may have a width in the first direction (X direction) that is approximately twice the width of the first microlens 182.

[0054] In an exemplary embodiment, the center line of the second microlens 184 in the first direction (X direction) also overlaps vertically with the pixel isolation film structure 150. In particular, the center of curvature of the second microlens 184 also overlaps vertically with a portion of the pixel isolation film structure 150 disposed between the first phase detection subpixel PPXa and the second phase detection subpixel PPXb. As a result, light entering from the left side based on the center line of the second microlens 184 is received by the second phase detection subpixel PPXb, and light entering from the right side is also received by the first phase detection subpixel PPXa. Therefore, based on the difference in the amount of light received by the first phase detection subpixel PPXa and the second phase detection subpixel PPXb, it may be determined whether the object 2000 ( FIG. 1 ) is located at an in-focus position.

[0055] In an exemplary embodiment, the first microlens 182 may have a first height h11, and the second microlens 184 may have a second height h12 that is higher than the first height h11. In some examples, the second height h12 may be about 110% to 300% of the first height h11, but is not limited thereto. Since the second height h12 of the second microlens 184 is higher than the first height h11 of the first microlens 182, the phase detection shared pixel PPX may exhibit excellent AF separation ratio characteristics.

[0056] For example, since the phase detection shared pixel PPX is distributed and disposed inside the pixel array PXA, the microlens for the image sensing pixel IPX and the microlens for the phase detection shared pixel PPX are generally formed by the same photoresist patterning process and etch-back process. However, according to the same photoresist patterning process and etch-back process, the microlens for the image sensing pixel IPX and the microlens for the phase detection shared pixel PPX are formed at the same height. If the microlens is formed to have a height (or curvature) having an optimal condition for the light reception of the image sensing pixel IPX, the AF separation ratio characteristic of the phase detection shared pixel PPX is degraded by the microlens with such height. If the microlens is formed to have a height (or curvature) having an optimal condition for the AF separation ratio characteristic of the phase detection shared pixel PPX, there is a problem that the SNR characteristic of the image sensing pixel IPX is degraded by the microlens with such height.

[0057] According to an exemplary embodiment, the second microlens 184 is formed to have a second height h12 that is even higher than the first microlens 182, such that the first microlens 182 has a curvature (or height) optimized for the SNR characteristics of the image sensing pixel IPX, while the second microlens 184 can have a curvature (or height) optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX.

[0058] Also, as described above, the second fence portion 160P of the color filter fence 160 disposed under the second microlens 184 may have a second width w12 that is wider than the first fence portion 160I of the color filter fence 160 disposed under the first microlens 182. Since the second fence portion 160P is formed to have a relatively wide width, the difference in the amount of light entering the first phase detection sub-pixel PPXa and the second phase detection sub-pixel PPXb through the second microlens 184 becomes larger, that is, the AF separation ratio characteristic is further improved.

[0059] As illustrated in Fig. 3 and Fig. 5 as examples, the plurality of image sensing pixels IPX may include a plurality of image sensing shared pixels SIPX. For example, the plurality of image sensing shared pixels SIPX may include two pixels adjacent in a first direction and two pixels adjacent in a second direction. For example, in Fig. 3, one image sensing shared pixel SIPX may include a first image sensing sub-pixel IPX1 to a fourth image sensing sub-pixel IPX4 arranged in a 2x2 matrix shape. However, the technical idea of ​​the present invention is not limited thereto, and one image sensing shared pixel SIPX may include a total of nine sub-pixels arranged in a 3x3 matrix shape, or a total of 16 sub-pixels arranged in a 4x4 matrix shape.

[0060] A color filter layer 170 sensing the same color may be disposed on the first image sensing sub-pixel IPX1 to the fourth image sensing sub-pixel IPX4 included in one image sensing shared pixel SIPX. For example, a green color filter layer G may be disposed on the first image sensing sub-pixel IPX1 to the fourth image sensing sub-pixel IPX4 indicated by dotted lines in FIG. 3. For example, a blue color filter layer B and a green color filter layer G may be disposed alternately on a plurality of image sensing shared pixels SIPX arranged along a first direction (X direction), and a red color filter layer R and a green color filter layer G may be disposed alternately on a plurality of image sensing shared pixels SIPX arranged along a second direction (Y direction). However, the color arrangement of the color filter layer 170 is not limited to the above. In another embodiment, at least a portion of the green color filter layer G may be replaced with a color filter layer 170 sensing white color.

[0061] 5, a blue color filter layer B is also disposed in a first color filter space 160S1 defined by a first fence portion 160I of the color filter fence 160. For example, in one shared pixel SIPX_B, a blue color filter layer B may be disposed on each of the first to fourth image sensing sub-pixels IPX1 to IPX4, and in one shared pixel SIPX_G adjacent thereto, a green color filter layer G may be disposed on each of the first to fourth image sensing sub-pixels IPX1 to IPX4.

[0062] 4, a green color filter layer G may be disposed in a second color filter space 160S2 defined by the first fence portion 160I and the second fence portion 160P of the color filter fence 160. In another embodiment, a color filter layer 170 sensing white may be disposed on the multiple phase-detection shared pixels PPX. In yet another embodiment, a green color filter layer G may be disposed on some of the multiple phase-detection shared pixels PPX, and a color filter layer 170 sensing white may be disposed on the other parts.

[0063] The phase-detection shared pixel PPX is also disposed at the position of the subpixels of two adjacent image-sensing shared pixels SIPX, so that the peripheral shared pixels SIPX_P1 and SIPX_P2 disposed adjacent to the phase-detection shared pixel PPX may include a first image-sensing subpixel IPX1, a second image-sensing subpixel IPX2, and a third image-sensing subpixel IPX3, respectively. For example, the peripheral shared pixel SIPX_P1 disposed on the left side of the phase-detection shared pixel PPX illustrated in FIG. 5 is composed of three subpixels corresponding to the blue color filter layer B, and the peripheral shared pixel SIPX_P2 disposed on the right side of the phase-detection shared pixel PPX is also composed of three subpixels corresponding to the red color filter layer R. However, the arrangement of the phase-detection shared pixel PPX is not limited thereto.

[0064] In an exemplary embodiment, in the low illuminance operation mode, the image sensor 100 is also controlled to sense light through the photoelectric conversion regions 120 in the image sensing shared pixels SIPX and generate pixel signals. In addition, in the high resolution operation mode, the image sensor 100 is also controlled to generate pixel signals individually for each of the image sensing sub-pixels IPX1 to IPX4 in the image sensing shared pixels SIPX. That is, in the low illuminance condition, a pixel signal may be generated for some or all of the four image sensing sub-pixels IPX1 to IPX4 as one unit, and in the high resolution condition, a pixel signal may be generated for each of the image sensing sub-pixels IPX1 to IPX4 as one unit. As a result, even if the size of the unit pixel is reduced by scaling down the image sensor 100 and the light receiving capacity (or light receiving area) of one sub-pixel is reduced, a wide dynamic range may be ensured.

[0065] Also, according to the image sensor 100 described above, the second microlens 184 is formed to have a second height h12 higher than that of the first microlens 182, so that the first microlens 182 has a curvature (or height) optimized for the SNR characteristics of the image sensing pixel IPX, while the second microlens 184 may have a curvature (or height) optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX. Also, the second width w12 of the second fence portion 160P of the color filter fence 160 is formed to be wider than the first width w11 of the first fence portion 160I, so that the AF separation ratio characteristics of the phase detection shared pixel PPX may be improved. Therefore, the image sensor 100 may quickly and accurately perform an autofocusing function, while the sensitivity of the image sensing pixel may be improved.

[0066] FIG. 7 is an equivalent circuit diagram of multiple pixels PX of image sensor 100 according to an example embodiment.

[0067] 7, the pixels PX are also arranged in a matrix form. Each of the pixels PX may include a transmission transistor TX and logic transistors RX, SX, and DX. Here, the logic transistors may include a reset transistor RX, a selection transistor SX, and a drive transistor DX (or a source follower transistor). The reset transistor RX may include a reset gate RG, the selection transistor SX may include a selection gate SG, and the transmission transistor TX may include a transmission gate TG.

[0068] Each of the pixels PX may further include a photoelectric conversion element PD and a floating diffusion region FD. The photoelectric conversion element PD also corresponds to the photoelectric conversion region 120 described in Figures 3 to 6. The photoelectric conversion element PD can generate and accumulate photocharges in proportion to the amount of light incident from the outside, and a photodiode, a phototransistor, a photogate, a pinned photodiode (PPD), or a combination thereof may be used.

[0069] The transmission gate TG can transmit the charge generated in the photoelectric conversion element PD to the floating diffusion region FD. The floating diffusion region FD can receive the charge generated in the photoelectric conversion element PD and store it as an accumulation. The drive transistor DX can be controlled by the amount of photocharge accumulated in the floating diffusion region FD.

[0070] The reset transistor RX can periodically reset the charge stored in the floating diffusion region FD. The drain electrode of the reset transistor RX is connected to the floating diffusion region FD, and the source electrode is connected to a power supply voltage VDD. When the reset transistor RX is turned on, the power supply voltage VDD connected to the source electrode of the reset transistor RX is transferred to the floating diffusion region FD. When the reset transistor RX is turned on, the charge stored in the floating diffusion region FD may be discharged, and the floating diffusion region FD may be reset.

[0071] The drive transistor DX is connected to a current source (not shown) located outside the pixels PX and functions as a source follower buffer amplifier to amplify the potential change in the floating diffusion region FD and output it to the output line VOUT.

[0072] The selection transistor SX can select a plurality of pixels PX in units of a row, and when the selection transistor SX is turned on, the power supply voltage VDD is also transmitted to the source electrode of the drive transistor DX.

[0073] Fig. 8 is a cross-sectional view showing an image sensor 100A according to an exemplary embodiment, and Fig. 9 is a horizontal cross-sectional view of a portion corresponding to CX1 in Fig. 3. In Figs. 8 and 9, the same reference numerals as those in Figs. 1 to 7 denote the same components.

[0074] 8 and 9, microlens structure 180A includes a first microlens 182 and a second microlens 184A, and second microlens 184A may include a lower microlens portion 184AB and an upper microlens portion 184AT. Lower microlens portion 184AB is disposed on color filter fence 160 and color filter layer 170, and upper microlens portion 184AT is also disposed on lower microlens portion 184AB.

[0075] In an exemplary embodiment, the lower microlens portion 184AB and the upper microlens portion 184AT are integrally formed and are also formed of one material layer. The lower microlens portion 184AB and the upper microlens portion 184AT are also parts of a hemispherical structure having different radii of curvature (or centers of curvature). A boundary line 184AC between the lower microlens portion 184AB and the upper microlens portion 184AT corresponds to a connecting line at a point where the curvature of the second microlens 184A changes abruptly, and a part of the second microlens 184A above the boundary line 184AC may be referred to as the upper microlens portion 184AT, and a part of the second microlens 184A below the boundary line 184AC may be referred to as the lower microlens portion 184BT. As shown in FIG. 9, the upper microlens portion 184AT may have a hemispherical shape that extends long in the first direction (X direction). In a plan view, the boundary line 184AC may have an elliptical shape that extends long in the first direction (X direction).

[0076] In an exemplary embodiment, the second microlens 184A may have a second height h12a that is higher than the first height h11 of the first microlens 182. Thus, the first microlens 182 may have a curvature (or height) optimized for the SNR characteristics of the image sensing pixel IPX, while the second microlens 184A may have a curvature (or height) optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX. In addition, the second microlens 184A may have characteristics optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX by being formed to include a lower microlens portion 184AB and an upper microlens portion 184AT having different curvatures.

[0077] Fig. 10 is a cross-sectional view showing an image sensor 100B according to an exemplary embodiment. Fig. 10 is a plan view of a portion corresponding to CX1 in Fig. 3. In Fig. 10, the same reference numerals as those in Figs. 1 to 9 denote the same components.

[0078] The microlens structure 180B includes a first microlens 182 and a second microlens 184B, and the second microlens 184B may include a lower microlens portion 184BB and an upper microlens portion 184BT. The lower microlens portion 184BB and the upper microlens portion 184BT are also parts of a hemispherical structure having different radii of curvature (or centers of curvature). As shown in FIG. 9, the upper microlens portion 184BT may have a hemispherical shape with a similar width in the second direction (Y direction) and a similar width in the first direction (X direction). In a plan view, the boundary line 184BC may include a portion overlapping with the first phase detection subpixel PPXa and a portion overlapping with the second phase detection subpixel PPXb. The second microlens 184B may have a curvature (or height) or shape optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX.

[0079] Fig. 11 is a cross-sectional view showing an image sensor 100C according to an exemplary embodiment. Fig. 11 is a cross-sectional view of a portion corresponding to the A1-A1' portion of Fig. 3. In Fig. 11, the same reference numerals as those in Figs. 1 to 10 denote the same components.

[0080] 11, the microlens structure 180C may include a first microlens 182 and a second microlens 184C, and the second microlens 184C may include a lower microlens portion 184CB and an upper microlens portion 184CT. The lower microlens portion 184CB and the upper microlens portion 184CT may include different materials.

[0081] For example, the lower microlens portion 184CB may include a light-transmitting organic material, and the upper microlens portion 184CT may include a photoresist material. The lower microlens portion 184CB may be formed by etching back a light-transmitting organic material layer, and the upper microlens portion 184CT may be formed by reflowing a photoresist pattern.

[0082] In an exemplary embodiment, the first microlens 182 may have a first height h11, the bottom microlens portion 184CB may have a second height h22a, and the top microlens portion 184CT may have a third height h22b. The second height h22a may be substantially the same as or similar to the first height h11, but is not limited thereto.

[0083] Fig. 12 is a layout diagram showing an image sensor 100D according to an exemplary embodiment, and Fig. 13 is a horizontal cross-sectional view of the CX2 portion of Fig. 12. In Figs. 12 and 13, the same reference numerals as those in Figs. 1 to 11 denote the same components.

[0084] 12 and 13, the phase-detection shared pixel PPX may also be disposed at the position of a subpixel of one image-sensing shared pixel SIPX, and the peripheral shared pixel SIPX_P disposed adjacent to the phase-detection shared pixel PPX may include a first image-sensing subpixel IPX1 and a second image-sensing subpixel IPX2. For example, the shared pixel SIPX_P disposed below the phase-detection shared pixel PPX illustrated in FIG. 13 is composed of two subpixels corresponding to a green color filter layer G (or has a green color filter layer G placed on top). One shared pixel SIPX_R disposed to the right of the phase-detection shared pixel PPX is also composed of four subpixels corresponding to a red color filter layer R. However, the arrangement of the phase-detection shared pixel PPX is not limited thereto.

[0085] FIG. 14 is a layout diagram illustrating an image sensor 100E according to an example embodiment.

[0086] Referring to FIG. 14, the first phase detection shared pixel PPXE1 may include a first phase detection sub-pixel PPXa1 and a second phase detection sub-pixel PPXb1 arranged side by side in the first direction (X direction), and the second phase detection shared pixel PPXE2 may include a third phase detection sub-pixel PPXa2 and a fourth phase detection sub-pixel PPXb2 arranged side by side in the second direction (Y direction).

[0087] In some examples, the first phase detection shared pixel PPXE1 calculates the position of the focus in the horizontal direction (X direction), and the second phase detection shared pixel PPXE2 is also controlled to calculate the position of the focus in the vertical direction (Y direction). The first phase detection shared pixel PPXE1 and the second phase detection shared pixel PPXE2 are randomly distributed or arranged, and the number of the first phase detection shared pixel PPXE1 and the second phase detection shared pixel PPXE2 are the same. In other embodiments, the number and arrangement of the first phase detection shared pixel PPXE1 and the second phase detection shared pixel PPXE2 may be different.

[0088] 15 to 25 are cross-sectional views illustrating a method for manufacturing an image sensor 100 according to an exemplary embodiment. In FIG. 15 to 25, cross sections corresponding to the A1-A1' cross section of FIG. 3 are illustrated in a process sequence. In FIG. 15 to 25, the same reference numerals as in FIG. 1 to FIG. 14 denote the same components.

[0089] 15, a substrate 110 having a first surface 110F1 and a second surface 110F2 opposite to each other is prepared. A mask pattern (not shown) is formed on the first surface 110F1 of the substrate 110, and a portion of the substrate 110 is removed from the first surface 110F1 of the substrate 110 using the mask pattern to form a trench 150T.

[0090] Then, an insulating liner 154 and a conductive layer 152 are sequentially formed in the trench 150T, and portions of the insulating liner 154 and the conductive layer 152 located on the first surface 110F1 of the substrate 110 are removed by a planarization process or the like, so that a pixel isolation film structure 150 can be formed in the trench 150T.

[0091] Thereafter, a photoelectric conversion region 120 including a photodiode region (not shown) and a well region (not shown) may be formed through an ion implantation process from the first surface 110F1 of the substrate 110. For example, the photodiode region may be formed by doping with N-type impurities, and the well region may be formed by doping with P-type impurities.

[0092] 16, a front structure 130 may be formed on a first surface 110F1 of a substrate 110. First, a gate electrode 132 may be formed on the first surface 110F1 of the substrate 110, and an ion implantation process may be performed on a portion of the first surface 110F1 of the substrate 110 to form a floating diffusion region (not shown) and an active region (not shown). Then, a conductive layer (not shown) may be formed on the first surface 110F1 of the substrate 110, the conductive layer may be patterned, and an insulating layer (not shown) may be formed to cover the patterned conductive layer by repeatedly performing the steps of forming the conductive layer (not shown) on the first surface 110F1 of the substrate 110, and forming an insulating layer (not shown) on the substrate 110.

[0093] A support substrate 140 may then be adhered onto the insulating layer 136 .

[0094] 17, the substrate 110 is turned upside down so that the second surface 110F2 of the substrate 110 faces upward. In this state, the bottom surface of the trench 150T is not exposed to the second surface 110F2.

[0095] 18, a portion of the substrate 110 may be removed from the second surface 110F2 of the substrate 110 by a planarization process such as a CMP process or an etch-back process until the conductive layer 152 is exposed. By performing the removing process, the level of the second surface 110F2 of the substrate 110 becomes lower. At this time, one image sensing pixel IPX surrounded by the pixel isolation film structure 150 is physically and electrically isolated from the adjacent image sensing pixel IPX.

[0096] Referring to FIG. 19, a rear insulating layer 166 may be formed on the second surface 110F2 of the substrate 110.

[0097] Thereafter, a barrier metal layer (not shown) and a low refractive index material layer (not shown) are sequentially formed on the rear insulating layer 166, and the barrier metal layer and the low refractive index material layer are patterned to form a barrier metal pattern 162 and a low refractive index material layer pattern 164. The barrier metal pattern 162 and the low refractive index material layer pattern 164 are also referred to as a color filter fence 160, and have a grid shape in a plan view, and also overlap the pixel isolation film structure 150 in the vertical direction.

[0098] In the patterning process, the color filter fence 160 is also patterned to include a relatively narrow first fence portion 160I and a relatively wide second fence portion 160P, where the color filter fence 160 defines a color filter space 160S, the first color filter space 160S1 overlaps the image sensing pixel IPX, and the second color filter space 160S2 also overlaps the phase detection sharing pixel PPX.

[0099] A passivation layer 168 can then be conformally formed on the inner walls of the color filter space 160S.

[0100] Referring to FIG. 20, a color filter layer 170 may be formed within the color filter space 160S.

[0101] 21, a microlens material layer 180L may be formed on the color filter layer 170. For example, the microlens material layer 180L may be formed using a light-transmitting organic material by a spin coating process or a chemical vapor deposition (CVD) process.

[0102] 22, a plurality of first mask patterns 322P1 may be formed on the microlens material layer 180L at positions overlapping with a plurality of image sensing pixels IPX. The first mask patterns 322P1 may include a photoresist pattern. For example, to form the first mask patterns 322P1, a photoresist material may be spin-coated, and then an exposure process, a baking process, and a development process may be sequentially performed.

[0103] 23, a plurality of second mask patterns 324P1 may be formed on the microlens material layer 180L at positions overlapping the phase detection shared pixels PPX. The second mask patterns 324P1 may include a photoresist pattern. The second mask patterns 324P1 are also formed to have a height and width greater than those of the first mask patterns 322P1. The second mask patterns 324P1 are also disposed at positions vertically overlapping both the first phase detection sub-pixel PPXa and the second phase detection sub-pixel PPXb.

[0104] Referring to FIG. 24, a reflow process can be performed to convert the first mask patterns 322P1 and the second mask patterns 324P1 into the first reflow patterns 322R1 and the second reflow patterns 324R1.

[0105] In an exemplary embodiment, the heat supplied in the reflow process can cause the first mask patterns 322P1 and the second mask patterns 324P1 to be deformed into a hemispherical shape, thereby forming the first reflow patterns 322R1 and the second reflow patterns 324R1.

[0106] In an exemplary embodiment, the reflow process is performed at a temperature of about 100° C. to 200° C. for a period of a few seconds to a few tens of minutes, but is not limited thereto.

[0107] 25, the microlens material layer 180L may be etched using the plurality of first reflow patterns 322R1 and the plurality of second reflow patterns 324R1 as an etching mask, so that the shapes of the plurality of first reflow patterns 322R1 and the plurality of second reflow patterns 324R1 may be transferred to the first microlens 182 and the second microlens 184. At this time, an edge portion of the first microlens 182 and an edge portion of the second microlens 184 may be connected to each other.

[0108] A capping layer 190 may then be formed over the microlens structure 180 , including the first microlens 182 and the second microlens 184 .

[0109] According to the above exemplary embodiment, the first mask patterns 322P1 may be formed first, and then the second mask patterns 324P1 may be formed to a relatively higher height. Then, the first mask patterns 322P1 and the second mask patterns 324P1 may be reflowed and an etching process may be performed to form the microlens structure 180. The image sensor 100 manufactured by the above method may quickly and accurately perform an autofocusing function, while improving the sensitivity of the image sensing pixels.

[0110] Next, according to an embodiment of the present technical idea, a method for manufacturing an image sensor is described, the method includes providing a plurality of pixels on a substrate, the plurality of pixels including one or more first pixels and one or more second pixels, providing a first microlens over each of the one or more first pixels using a first process, and providing a second microlens over each of the one or more second pixels using a second process, the first microlens having a different shape than the second microlens.

[0111] In some cases, the method further includes forming a microlens material layer over a plurality of image sensing pixels, the first step including forming a first mask pattern, forming a first reflow pattern based on the first mask pattern, and forming the first microlens from the microlens material layer based on the first reflow pattern, and the second step including forming a second mask pattern, forming a second reflow pattern based on the second mask pattern, and forming the second microlens based on the second reflow pattern.

[0112] In some cases, the one or more first pixels include image sensing pixels, and the one or more second pixels include phase difference sharing pixels configured to generate a phase signal to calculate a phase difference between images. In some cases, a height of the second microlens is greater than a height of the first microlens.

[0113] 26-28 are cross-sectional views illustrating a method for manufacturing an image sensor 100 according to an example embodiment.

[0114] First, the steps described with reference to FIGS. 15 to 21 are carried out.

[0115] Referring to FIG. 26, a plurality of second mask patterns 324P2 may be first formed on the microlens material layer 180L at positions overlapping with the phase detection sharing pixels PPX.

[0116] 27, a plurality of first mask patterns 322P2 may be formed on the microlens material layer 180L at positions overlapping with a plurality of image sensing pixels IPX. The first mask patterns 322P2 may be formed to have a smaller height and width than the second mask patterns 324P2.

[0117] Referring to FIG. 28, a reflow process may be performed to convert the first mask patterns 322P2 and the second mask patterns 324P2 into the first reflow patterns 322R2 and the second reflow patterns 324R2.

[0118] Thereafter, the process described with reference to FIG. 25 is performed to complete the image sensor 100.

[0119] 29-32 are cross-sectional views illustrating a method for manufacturing an image sensor 100 according to an example embodiment.

[0120] First, the steps described with reference to FIGS. 15 to 21 are carried out.

[0121] Referring to FIG. 29, a plurality of first mask patterns 322P3 may be formed on the microlens material layer 180L at positions overlapping with a plurality of image sensing pixels IPX.

[0122] Referring to FIG. 30, a first reflow process may be performed to convert the first mask patterns 322P3 into the first reflow patterns 322R3.

[0123] Referring to FIG. 31, a plurality of second mask patterns 324P3 may be formed on the microlens material layer 180L at positions overlapping with the phase detection sharing pixels PPX.

[0124] 32, the second reflow process is performed to convert the second mask patterns 324P3 into the second reflow patterns 324R3. Meanwhile, since the first reflow patterns 322R3 have already been deformed into a hemispherical shape in the first reflow process, the shape of the first reflow patterns 322R3 does not change significantly in the second reflow process.

[0125] Thereafter, the process described with reference to FIG. 25 is performed to complete the image sensor 100.

[0126] 33 to 36 are cross-sectional views illustrating a method for manufacturing the image sensor 100A according to an exemplary embodiment.

[0127] First, the steps described with reference to FIGS. 15 to 21 are carried out.

[0128] 33, a plurality of first mask patterns 332P1 may be formed on the microlens material layer 180L at positions overlapping with a plurality of image sensing pixels IPX, and a plurality of second mask patterns 334P1 may be formed on the microlens material layer 180L at positions overlapping with a phase detection sharing pixel PPX. The plurality of first mask patterns 332P1 and the plurality of second mask patterns 334P1 are formed to have the same height since they are formed in the same photoresist patterning process.

[0129] Referring to FIG. 34, a plurality of third mask patterns 334P2 may be formed on the plurality of second mask patterns 334P1 at positions overlapping with the phase detection shared pixels PPX. The width and height of the plurality of third mask patterns 334P2 are also determined in consideration of the curvature and shape of the second microlenses 184A to be formed in a subsequent process. For example, as shown in FIG. 34, when the plurality of third mask patterns 334P2 are formed narrower than the plurality of second mask patterns 334P1, the second microlenses 184A are also formed to have different curvatures (or curvature radii) at the lower and upper sides. In contrast, when the plurality of third mask patterns 334P2 are formed to have substantially the same width as the plurality of second mask patterns 334P1, the second microlenses 184 are also formed to have a hemispherical shape with substantially the same center of curvature over the entire surface, as shown in FIG. 4.

[0130] Referring to FIG. 35, a reflow process can be performed to convert the first mask patterns 332P1 and the second mask patterns 334P1 into the first reflow patterns 332R1 and the second reflow patterns 334R1.

[0131] Referring to FIG. 36, the shapes of the first reflow patterns 332R1 and the second reflow patterns 334R1 can be transferred to the first microlens 182 and the second microlens 184A by etching the microlens material layer 180L using the first reflow patterns 332R1 and the second reflow patterns 334R1 as an etching mask.

[0132] 37 to 40 are cross-sectional views illustrating a method for manufacturing an image sensor 100B according to an example embodiment.

[0133] First, the steps described with reference to FIGS. 15 to 21 are carried out.

[0134] 37, a plurality of first mask patterns 342P1 may be formed on the microlens material layer 180L at positions overlapping with a plurality of image sensing pixels IPX, and a plurality of second mask patterns 344P1 may be formed on the microlens material layer 180L at positions overlapping with a phase detection sharing pixel PPX. The plurality of first mask patterns 342P1 and the plurality of second mask patterns 344P1 are formed to have the same height since they are formed by the same photoresist patterning process.

[0135] Referring to FIG. 38, a reflow process can be performed to convert the first mask patterns 342P1 and the second mask patterns 344P1 into the first reflow patterns 342R1 and the second reflow patterns 344R1.

[0136] Referring to FIG. 39, the microlens material layer 180L is etched using the plurality of first reflow patterns 342R1 and the plurality of second reflow patterns 344R1 as an etching mask, so that the shapes of the plurality of first reflow patterns 342R1 and the plurality of second reflow patterns 344R1 are also transferred to the first microlens 182 and the lower microlens portion 184CB.

[0137] The lower microlens portion 184CB is also formed to have a second height h22a that is substantially the same as or similar to the height h11 of the first microlens 182.

[0138] Thereafter, a plurality of third mask patterns 344P2 can be formed on the lower microlens portion 184CB.

[0139] 40, a reflow process is performed to convert the third mask patterns 344P2 into the upper microlens portions 184CT. The reflow process also forms the lower microlens portions 184CB into a hemispherical shape having a third height h22b.

[0140] A capping layer 190 may then be formed over the microlens structure 180, including the first microlens 182 and the second microlens 184C.

[0141] According to the above exemplary embodiment, the first microlens 182 and the second microlenses 184, 184A, 184B, and 184C are also formed to have different heights. Thus, the first microlens 182 may have a curvature (or height) optimized for the SNR characteristics of the image sensing pixel IPX, while the second microlenses 184, 184A, 184B, and 184C may have a curvature (or height) optimized for the AF separation ratio characteristics of the phase detection shared pixel PPX. The image sensors 100 to 100E manufactured by the above method may quickly and accurately perform an autofocusing function, while improving the sensitivity of the image sensing pixels.

[0142] As described above, the drawings and the specification disclose exemplary embodiments. In this specification, specific terms are used to describe the embodiments, but they are only used for the purpose of describing the technical idea of ​​the present disclosure, and are not used to limit the meaning or the scope of the present disclosure described in the claims. Therefore, a person skilled in the art will understand that various modifications and other equivalent embodiments are possible. Therefore, the true technical scope of protection of the present disclosure is defined by the technical idea of ​​the claims. [Explanation of symbols]

[0143] 100 Image Sensor 120 Photoelectric conversion area 160 Color Filter Fence 180 Microlens Structure IPX Image Sensing Pixel PPX Phase detection shared pixel

Claims

1. 1. An image sensor including a pixel array, The pixel array includes: a plurality of image sensing pixels formed in a substrate; a phase-detection shared pixel including two phase-detection sub-pixels formed in the substrate and arranged side by side; a color filter fence disposed over the image sensing pixels and the phase detection shared pixels, the color filter fence including a plurality of color filter spaces; a plurality of color filter layers respectively disposed within the plurality of color filter spaces over the plurality of image sensing pixels and the phase detection shared pixel; a first microlens disposed over each of the plurality of image sensing pixels and having a first height; a second microlens disposed on the phase detection shared pixel so as to overlap the two phase detection sub-pixels in a vertical direction, the second microlens having a second height higher than the first height; 11. An image sensor comprising: a first microlens having a curvature different from a curvature of the second microlens; and both the first microlens and the second microlens being constructed from the same single material.

2. The color filter fence is A barrier metal pattern; 2. The image sensor of claim 1, further comprising: a low refractive index material layer pattern disposed on the barrier metal pattern and having a first refractive index.

3. 3. The image sensor of claim 2, wherein the first refractive index is greater than 1.0 and less than or equal to 1.

4.

4. the two phase detection sub-pixels are disposed adjacent to each other in a first direction parallel to a top surface of the substrate; the color filter fence includes a first fence portion and a second fence portion, the first fence portion vertically overlaps a boundary between the plurality of image sensing pixels, the second fence portion vertically overlaps a boundary between one of the phase detection sharing pixels and an image sensing pixel adjacent to the one of the phase detection sharing pixels in the first direction; 2. The image sensor of claim 1, wherein the first fence portion has a first width along the first direction, and the second fence portion has a second width along the first direction that is wider than the first width.

5. The plurality of color filter spaces include a first color filter space disposed on the plurality of image sensing pixels and defined by the first fence portion; a second color filter space disposed on the phase-detection shared pixel and defined by the first fence portion and the second fence portion; The image sensor of claim 4 , wherein the second color filter space vertically overlaps the two phase detection sub-pixels.

6. The image sensor of claim 5 , wherein the second color filter space has an area larger than an area of ​​the first color filter space when viewed from above.

7. The plurality of image sensing pixels includes a plurality of image sensing shared pixels; Each of the plurality of image sensing shared pixels includes a plurality of image sensing sub-pixels, and a color filter layer of the same color is disposed on the plurality of image sensing sub-pixels; The image sensor of claim 1 , wherein the plurality of image sensing sub-pixels are arranged in a 2×2 matrix shape.

8. a pixel isolation film structure extending through the substrate and disposed between the plurality of image sensing pixels; The image sensor of claim 1 , wherein a portion of the pixel isolation film structure is disposed between the two phase-detection sub-pixels of the phase-detection shared pixel.

9. The second microlens is a lower microlens portion disposed on the color filter layer; an upper microlens portion disposed on the lower microlens portion; The image sensor of claim 1 , wherein the lower micro-lens portion and the upper micro-lens portion have different curvatures.

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