Image sensor with grid structure

Abstract

An image sensor may include: a photoelectric conversion element within a substrate; a separation structure within the substrate and between the photoelectric conversion elements; an insulating structure on the substrate and the separation structure; a plurality of color filters on the insulating structure; a grid structure including a lower horizontal structure disposed on the insulating structure, and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters; an upper horizontal structure covering upper surfaces of the plurality of color filters; and a capping layer covering the upper horizontal structure and the lattice structure. The lattice structure may also include an air gap surrounded by a vertical structure, a lower horizontal structure, and a capping layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2023-0124894 filed in the Korean Intellectual Property Office on September 19, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to an image sensor including a grid structure. Background Art

[0004] An image sensor is a semiconductor-based sensor that can receive light and generate electrical signals, and may include a pixel array having a plurality of pixels, a logic circuit for driving the pixel array and generating an image, etc. Each pixel may include a photodiode, and a pixel circuit that can convert the charge generated by the photodiode into an electrical signal. Summary of the invention

[0005] One or more example embodiments provide an image sensor including a grid structure including an air gap.

[0006] According to example embodiments, an image sensor may include: a photoelectric conversion element in a substrate; a separation structure in the substrate and between the photoelectric conversion elements; an insulating structure on the substrate and the separation structure; a plurality of color filters on the insulating structure; a grid structure including a lower horizontal structure disposed on the insulating structure, and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters; an upper horizontal structure covering an upper surface of the plurality of color filters; and a capping layer covering the upper horizontal structure and the grid structure. The grid structure may also include an air gap surrounded by the vertical structure, the lower horizontal structure, and the capping layer.

[0007] According to example embodiments, an image sensor may include: a photoelectric conversion element in a substrate; a separation structure in the substrate and between the photoelectric conversion elements; an insulating structure on the substrate and the separation structure; a plurality of color filters on the insulating structure; a protective layer covering the insulating structure and the plurality of color filters; and a capping layer covering the protective layer. The lower end of the capping layer may be at a height higher than the lower surface of the plurality of color filters, and the protective layer and the capping layer define an air gap between the plurality of color filters.

[0008] According to an example embodiment, an image sensor may include: a lower chip including a logic circuit; and an upper chip on the lower chip, the upper chip being bonded to the lower chip. The upper chip may include: a photoelectric conversion element disposed in a substrate; a separation structure disposed in the substrate and between the photoelectric conversion elements; an insulating structure disposed on the substrate and the separation structure; a plurality of color filters disposed on the insulating structure and spaced apart from each other; a grid structure disposed between the plurality of color filters, the grid structure including a lower horizontal structure disposed on the insulating structure, and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters; an upper horizontal structure covering the upper surfaces of the plurality of color filters; a capping layer covering the upper horizontal structure and the grid structure; and a microlens disposed on the capping layer. The grid structure may include an air gap surrounded by the vertical structure, the lower horizontal structure, and the capping layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and other aspects and features will become more apparent from the following detailed description of one or more example embodiments taken in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is a block diagram briefly illustrating an image sensor according to one or more example embodiments;

[0011] Figure 2A is a diagram schematically showing an illustrative example of a pixel circuit of an image sensor according to one or more example embodiments;

[0012] Figure 2B is a diagram schematically showing an illustrative example of a pixel circuit of an image sensor according to one or more example embodiments;

[0013] Figure 3 is a plan view schematically illustrating an image sensor according to one or more example embodiments;

[0014] Figure 4 yes Figure 3 an enlarged view of the image sensor shown;

[0015] Figure 5 is along Figure 4 A vertical cross-sectional view of the image sensor shown taken along line II';

[0016] Figure 6 yes Figure 5 an enlarged view of the image sensor shown;

[0017] Figure 7 is along Figure 4 A vertical cross-sectional view of the image sensor shown taken along line II-II';

[0018] Figure 8is with Figures 9 to 12 vertical cross-sectional views shown together in process order for describing a method of manufacturing an image sensor according to one or more example embodiments;

[0019] Fig. 9 is with Figure 8 as well as Figures 10 to 12 vertical cross-sectional views shown together in process order for describing a method of manufacturing an image sensor according to one or more example embodiments;

[0020] Fig.10 is with Figure 8 , Fig. 9 , Fig.11 and Fig.12 vertical cross-sectional views shown together in process order for describing a method of manufacturing an image sensor according to one or more example embodiments;

[0021] Fig.11 is with Figures 8 to 10 as well as Fig.12 vertical cross-sectional views shown together in process order for describing a method of manufacturing an image sensor according to one or more example embodiments;

[0022] Fig.12 is with Figures 8 to 11 vertical cross-sectional views shown together in process order for describing a method of manufacturing an image sensor according to one or more example embodiments;

[0023] Fig.13 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0024] Fig.14 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0025] Fig.15 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0026] Fig.16 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0027] Fig.17 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0028] Fig.18 is a vertical cross-sectional view of an image sensor according to one or more example embodiments;

[0029] Fig.19 is a vertical cross-sectional view of an image sensor according to one or more example embodiments; and

[0030] Fig. 20 is a vertical cross-sectional view of an image sensor according to one or more example embodiments. DETAILED DESCRIPTION

[0031] Hereinafter, one or more exemplary embodiments of the technical idea of ​​the inventive concept will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same components in the drawings, and repeated descriptions thereof are omitted.

[0032] According to one or more example embodiments, terms such as "upper", "upper part", "upper surface", "lower", "lower part", "lower surface", "bottom", "side surface", "upper end", "lower end", etc. are indicated with figure marks, and it is understood that unless otherwise indicated, reference is made based on the drawings. It should also be understood that these terms are relative to each other and do not indicate the position of the component relative to the direction of gravity. In addition, "surrounding" can mean that one component is completely surrounded by another component, or one component is partially surrounded by another component. In addition, in an embodiment, surrounding can describe the orientation or arrangement of a component along a specific axis or a specific cross-sectional view.

[0033] First, refer to Figure 1 , illustrative examples of image sensors according to one or more example embodiments will be described. Figure 1 is a simple block diagram of an image sensor according to one or more example embodiments.

[0034] refer to Figure 1 , the image sensor 1 may include a pixel array 10 and a logic circuit 20. The pixel array 10 may include a plurality of pixels PX arranged in an array along a plurality of rows and a plurality of columns. Each of the plurality of pixels PX may include at least one photoelectric conversion element that generates charges in response to light, and a pixel circuit that generates a pixel signal corresponding to the charges generated by the photoelectric conversion element. The photoelectric conversion element may include a photodiode formed of a semiconductor material and / or an organic photodiode formed of an organic material.

[0035] For example, the pixel circuit may include a floating diffusion region, a transfer transistor, a reset transistor, a drive transistor, and a selection transistor. The configuration of the pixel PX may vary according to the embodiment. For example, each pixel PX may include an organic photodiode containing an organic material, or may be implemented as a digital pixel. When the pixel PX is implemented as a digital pixel, each pixel PX may include an analog-to-digital converter for outputting a digital pixel signal.

[0036] The logic circuit 20 may include a circuit for controlling the pixel array 10. For example, the logic circuit 20 may include a row driver 21, a readout circuit 22, a column driver 23, and a control logic 24. The row driver 21 may drive the pixel array 10 in units of row lines. For example, the row driver 21 generates a transfer control signal for controlling a transfer transistor of a pixel circuit, a reset control signal for controlling a reset transistor, and a selection control signal for controlling a selection transistor, and may input a signal to the pixel array 10 in units of row lines.

[0037] The readout circuit 22 may include a correlated double sampler CDS, an analog-to-digital converter ADC, etc. The correlated double sampler may be connected to the pixel PX through a column line. The correlated double sampler may read a pixel signal from the pixel PX connected to a row line selected by a row line selection signal of the row driver 21 through a column line. The analog-to-digital converter may convert the pixel signal detected by the correlated double sampler into a digital pixel signal and send it to the column driver 23.

[0038] The column driver 23 may include a latch or buffer circuit capable of temporarily storing a digital pixel signal, an amplifier circuit, etc., and may process the digital pixel signal received from the readout circuit 22. The row driver 21, the readout circuit 22, and the column driver 23 may be controlled by the control logic 24. The control logic 24 may include a timing controller for controlling the operation timing of the row driver 21, the readout circuit 22, and the column driver 23.

[0039] Among the pixels PX, the pixels PX arranged at the same position in the horizontal direction may share the same column line. In an example, the pixels PX arranged at the same position in the vertical direction may be simultaneously selected by the row driver 21, and the pixel signals are output through the column lines. In an example, the readout circuit 22 may simultaneously obtain the pixel signals from the pixels PX selected by the row driver 21 through the column lines. The pixel signal may include a reset voltage and a pixel voltage, and the pixel voltage may be a voltage in which the charge generated in response to light in each pixel PX is reflected in the reset voltage.

[0040] Next, we will refer to Figure 2A and Figure 2B Various examples of a pixel circuit of an image sensor according to one or more example embodiments are described. Figure 2A and Figure 2B is a diagram briefly showing an illustrative example of a pixel circuit of an image sensor according to one or more example embodiments.

[0041] In the example, refer to Figure 1 and Figure 2A, each of the plurality of pixels PX may include a photodiode PD and a pixel circuit, and the pixel circuit may include a transfer transistor TX, a reset transistor RX, a selection transistor SX, and a drive transistor DX.

[0042] The photodiode PD may generate and accumulate charges in response to light incident from the outside. The pixel circuit may further include a floating diffusion region FD that accumulates charges generated in the photodiode PD.

[0043] According to an embodiment, the photodiode PD may be replaced by a phototransistor, a photogate, or a pinned photodiode. The photodiode PD may be referred to and described as a “photoelectric conversion element.” Therefore, the photoelectric conversion element may be a photodiode, a phototransistor, a photogate, or a pinned photodiode.

[0044] The transfer transistor TX may move the charges generated in the photodiode PD to the floating diffusion region FD. The floating diffusion region FD may store the charges generated in the photodiode PD. The voltage output by the drive transistor DX may vary according to the amount of charges accumulated in the floating diffusion region FD.

[0045] The reset transistor RX may reset the voltage of the floating diffusion region FD by removing the charge accumulated in the floating diffusion region FD. The drain electrode of the reset transistor RX may be connected to the floating diffusion region FD, and the source electrode may be connected to the 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 applied to the floating diffusion region FD, and the charge accumulated in the floating diffusion region FD may be removed.

[0046] The drive transistor DX can operate as a source follower buffer amplifier. The drive transistor DX can amplify the voltage change in the floating diffusion area FD and output it to one of the column lines COL1 and COL2. The selection transistor SX can select the pixel PX to be read row by row. When the selection transistor SX is turned on, the voltage of the drive transistor DX can be output to one of the column lines COL1 and COL2. When the selection transistor SX is turned on, the reset voltage or the pixel voltage can be output through the column lines COL1 and COL2.

[0047] exist Figure 2A In one or more example embodiments shown, each of the plurality of pixels PX may include all of a photodiode PD and a transfer transistor TX, as well as a reset transistor RX, a selection transistor SX, and a drive transistor DX. Embodiments are not limited thereto, and may be as follows Figure 2B Modified as shown.

[0048] In the modified example, reference Figure 1 and Figure 2BTwo or more pixels adjacent to each other may share at least some of the transistors included in the pixel circuit. For example, four pixels adjacent to each other may share a floating diffusion region FD, a reset transistor RX, first and second drive transistors DX1 and DX2, and a selection transistor SX.

[0049] In an example, the first photodiode PD1 and the first transfer transistor TX1 of the first pixel may be connected to the floating diffusion region FD. Likewise, the second to fourth photodiodes PD2 to PD4 of the second to fourth pixels may be connected to the floating diffusion region FD through the second to fourth transfer transistors TX2 to TX4.

[0050] In an example, the floating diffusion regions FD included in each pixel may be connected to each other using an interconnection pattern or the like so that the first to fourth transfer transistors TX1 to TX4 are common to one floating diffusion region FD.

[0051] In another example, the floating diffusion region FD included in each pixel may be formed as a floating diffusion region within a substrate that may be formed of a semiconductor material.

[0052] The pixel circuit may include a reset transistor RX, a first drive transistor DX1 and a second drive transistor DX2, and a selection transistor SX. The reset transistor RX may be controlled by a reset control signal RG, and the selection transistor SX may be controlled by a selection control signal SEL. For example, in addition to the transfer transistor TX, each of the four pixels may further include a transistor. Among the four transistors included in the four pixels, two transistors are connected in parallel to provide a first drive transistor DX1 and a second drive transistor DX2, and one of the remaining two transistors is used as a selection transistor SX, and the other may be configured to provide a reset transistor RX.

[0053] refer to Figure 2B The pixel circuit described is only an example and is not necessarily limited to this form. For example, one of the four transistors may be designated as a drive transistor, and another may be designated as a select transistor. Additionally, by connecting the remaining two transistors in series and designating them as a first reset transistor and a second reset transistor, an image sensor that can adjust the conversion gain of a pixel can be realized. Alternatively, the pixel circuit may vary depending on the number of transistors included in each pixel. Therefore, reference Figure 2A and Figure 2B The described pixel circuits are illustrative examples for implementing an image sensor according to one or more example embodiments, and the embodiments are not limited thereto.

[0054] Next, refer to Figures 3 to 5, an example of an image sensor structure according to one or more example embodiments will be described. Figures 3 to 5 is a diagram schematically illustrating an image sensor according to one or more example embodiments. Figure 3 is a plan view schematically illustrating an image sensor according to one or more example embodiments, Figure 4 yes Figure 3 An enlarged view of the image sensor is shown, and Figure 5 is along Figure 4 A vertical cross-sectional view of the image sensor taken along line II' is shown.

[0055] refer to Figures 3 to 5 , the image sensor 1 according to the embodiment may have a stacked chip structure using at least two chips. For example, the image sensor 1 may include a first chip structure 103, and a second chip structure 203 on the first chip structure 103. The first chip structure 103 may be a logic chip, and the second chip structure 203 may be an image sensor chip. In another example, the first chip structure 103 may be a stacked chip structure including a logic chip and a memory chip.

[0056] The first chip structure 103 of the image sensor 1 may include a first substrate 106, a device isolation film 109s defining an active area 109a on the first substrate 106, a first circuit element 112 and a first interconnection structure 115 on the first substrate 106, and a first insulating structure 118 covering the first circuit element 112 and the first interconnection structure 115 on the first substrate 106.

[0057] The first substrate 106 may be a semiconductor substrate. For example, the first substrate 106 may be a substrate formed of a semiconductor material, such as a single crystal silicon substrate. The first circuit element 112 may include an element such as a transistor including a gate 112a and a source / drain 112b.

[0058] The second chip structure 203 may include a second substrate 206 having a first surface 206s1 and a second surface 206s2 facing each other, a device isolation film 218 disposed on the first surface 206s1 of the second substrate 206 and defining an active region, a second circuit element 224 and a second interconnect structure 227 disposed between the first surface 206s1 of the second substrate 206 and the first chip structure 103, and a second insulating structure 230 covering the second circuit element 224 and the second interconnect structure 227 between the first surface 206s1 of the second substrate 206 and the first chip structure 103. The first surface 206s1 of the second substrate 206 may face the first chip structure 103. The device isolation film 218 may be formed of an insulating material such as silicon oxide. The second circuit element 224 and the second interconnect structure 227 disposed below the first surface 206s1 of the second substrate 206 may form a circuit interconnect structure. Therefore, the circuit interconnect structure may be disposed below the first surface 206s1 of the second substrate 206.

[0059] In some embodiments, the upper surface of the layer of the device isolation film 218 may be referred to as a first surface 206 s 1 ′ of the second substrate 206 .

[0060] The second substrate 206 may be a semiconductor substrate. For example, the second substrate 206 may be a substrate formed of a semiconductor material, such as a single crystal silicon substrate.

[0061] The image sensor 1 may further include a plurality of pixel regions PX disposed within the second substrate 206. The pixel regions PX may correspond to the pixel regions PX in the above reference. Figures 1 to 2B The pixel PX described above. Each of the plurality of pixel regions may include a photoelectric conversion element PD. The photoelectric conversion element PD may generate and accumulate charges corresponding to incident light. For example, the photoelectric conversion element PD may include a photodiode, a phototransistor, a photogate, a pinned photodiode (PPD), and a combination thereof.

[0062] Each photoelectric conversion element PD may be a photodiode that may be formed in the second substrate 206. Therefore, each of the plurality of pixel regions may include a photodiode. The plurality of pixel regions may each be referred to as a photoelectric conversion element PD or a photodiode.

[0063] The second chip structure 203 may further include a separation structure 215. The separation structure 215 may be arranged to surround each photoelectric conversion element PD. The separation structure 215 may vertically penetrate at least a portion of the second substrate 206. For example, the separation structure 215 may vertically penetrate the second substrate 206. The separation structure 215 may be disposed in a separation groove 212 that vertically penetrates the second substrate 206. The separation structure 215 may be connected to the device isolation film 218. Therefore, the separation structure 215 may penetrate the second substrate 206 between the device isolation film 218 and the second surface 206s2 of the second substrate 206. The separation structure 215 may have a substantially vertical side.

[0064] The separation structure 215 may include a separation pattern 213b and a separation insulating layer 213a covering the side surface of the separation pattern 213b. For example, the separation insulating layer 213a may include silicon oxide, and the separation pattern 213b may include polysilicon. The separation pattern 213b may also be referred to as a silicon pattern or a polysilicon pattern. The separation insulating layer 213a may be formed of a single material layer.

[0065] The separation pattern 213b may be formed of a material capable of applying a voltage to the separation pattern 213b so as to significantly reduce or prevent interference or influence between the photoelectric conversion elements PD. For example, the separation pattern 213b may include a conductive material (e.g., doped polysilicon). In an example, the separation pattern 213b may be formed of doped polysilicon having an N-type conductivity type. In another example, the separation pattern 213b may be formed of doped polysilicon having a P-type conductivity type.

[0066] The second circuit element 224 may include a transmission gate TG and an active element 221. The active element 221 may be a transistor including a gate 221a and a source / drain 221b. The transmission gate TG may transfer charges from an adjacent photoelectric conversion element PD to an adjacent floating diffusion region. The active element 221 may be Figure 2A and Figure 2B Various transistors (e.g., drive transistor, reset transistor, and select transistor) of the pixel circuit described in.

[0067] The transfer gate TG may be a vertical transfer gate including a portion extending from the first surface 206 s 1 of the second substrate 206 into the interior of the second substrate 206 .

[0068] The second interconnect structure 227 may include multi-layer wirings located at different heights, and vias electrically connecting the multi-layer wirings and electrically connecting the multi-layer wirings to the second circuit element 224 .

[0069] The first insulating structure 118 and the second insulating structure 230 may contact and bond with each other. Each of the first insulating structure 118 and the second insulating structure 230 may be formed of a multilayer including different types of insulating layers. For example, the second insulating structure 230 may be formed of a multilayer including at least two of a silicon oxide layer, a low dielectric layer, and a silicon nitride layer.

[0070] The second chip structure 203 may further include an insulating structure 240 disposed on the second surface 206s2 of the second substrate 206. The insulating structure 240 may cover the separation structure 215.

[0071] The insulating structure 240 may include an anti-reflection layer that may prevent light reflection that may occur due to a sudden change in the refractive index on the second surface 206s2 of the second substrate 206 that may be formed of silicon. The insulating structure 240 may include an anti-reflection layer that may adjust the refractive index to allow incident light to travel to the photoelectric conversion element PD with high transmittance. The insulating structure 240 may also be referred to as an anti-reflection structure or an anti-reflection layer.

[0072] The insulating structure 240 may have transparency at visible wavelengths and may include a material having a negative charge to prevent charges due to dangling bonds on the second surface 206s2 of the substrate 206. Additionally, the insulating structure 240 may include a material that can adjust the peak value of the transmittance by adjusting the thickness. The insulating structure 240 may include at least one of silicon oxide, aluminum oxide, and hafnium oxide. The insulating structure 240 may be formed of a single layer or multiple layers.

[0073] The second chip structure 203 may include a color filter CF. For example, the color filter CF may include a color filter CF that filters different colors. For example, the color filter CF may include at least one of a green filter, a blue filter, a red filter, a white filter, and a yellow filter.

[0074] The color filter CF may be disposed on the insulating structure 240. The color filter CF may vertically overlap the corresponding photoelectric conversion element PD. The color filter CF may allow light of a specific wavelength to pass through and reach the photoelectric conversion element PD. For example, the color filter CF may be formed of a material in which a resin is mixed with a pigment containing a metal or a metal oxide.

[0075] In one or more example embodiments, the color filter CF may have a rectangular shape when viewed in a plan view. The color filters CF configured to filter the same color may be referred to as a color filter group. In one or more example embodiments, the plurality of color filter groups may each be arranged in a 2×2 array. In some embodiments, the plurality of color filter groups may each be arranged in a 1×1 array or a 3×3 array.

[0076] The second chip structure 203 may further include a protective layer P. The protective layer P may be disposed on the insulating structure 240 and the color filter CF. For example, the protective layer P may cover the insulating structure 240 and the color filter CF, and may be conformally disposed along the surfaces of the insulating structure 240 and the color filter CF. In one or more example embodiments, the protective layer P may include a vertical structure Pa, a lower horizontal structure Pb, and an upper horizontal structure Pc. For example, a portion of the protective layer P that covers the insulating structure 240 and extends in the horizontal direction may be referred to as a lower horizontal structure Pb. A portion of the protective layer P that extends in the vertical direction and covers the side surface of the color filter CF may be referred to as a vertical structure Pa. A portion of the protective layer P that covers the upper surface of the color filter CF and extends in the horizontal direction may be referred to as an upper horizontal structure Pc.

[0077] The vertical structure Pa, the lower horizontal structure Pb, and the upper horizontal structure Pc may be connected to each other and may be formed integrally. In the top view, each color filter CF may be surrounded by the vertical structure Pa. The lower horizontal structure Pb may extend in the horizontal direction between the color filters CF. The thickness Tp of the protective layer P may be from about 3nm to about 200nm. For example, the thickness Tp of each of the vertical structure Pa, the lower horizontal structure Pb, and the upper horizontal structure Pc may be from about 3nm to about 200nm.

[0078] The protective layer P may include at least one of the following: silicon dioxide (SiO 2 ), silicon nitride (SiN), aluminum oxide (Al 2 O 3 )、ZrO 2 )、Tantalum oxide(Ta 2 O 5 ), titanium oxide (TiO 2 )、Lanthanum oxide(La 2 O 3 ), praseodymium oxide (Pr 2 O 3 ), cerium oxide (CeO 2 ), neodymium oxide (Nd 2 O 3 ), promethium oxide (Pm 2 O 3 ), samarium oxide (Sm 2 O 3 ), europium oxide (Eu 2 O 3 ), gadolinium oxide (Gd 2 O 3 ), terbium oxide (Tb 2 O 3 ), Dysprosium oxide (Dy 2 O 3 ), holmium oxide (Ho 2 O3 ), thulium oxide (Tm 2 O 3 ), Ytterbium oxide (Yb 2 O 3 ), Lutetium oxide (Lu 2 O 3 ) or yttrium oxide (Y 2 O 3 ).

[0079] The vertical structures Pa arranged adjacent to each other and the lower horizontal structure Pb therebetween may form a grid structure 250. In one or more example embodiments, the grid structure 250 may overlap vertically with the separation structure 215. In one or more example embodiments, the grid structure 250 may have a width different from that of the separation structure 215. For example, the width of the grid structure 250 may be greater than the width of the separation structure 215. The grid structure 250 may extend in a horizontal direction between the color filters CF. In one or more example embodiments, the grid structure 250 may be disposed between the color filters CF. The thickness of each color filter CF may be greater than the thickness of the grid structure 250. The color filter CF may cover the side of the grid structure 250 on the insulating structure 240. In a plan view, each color filter CF may be surrounded by the vertical structure Pa.

[0080] The second chip structure 203 may further include a capping layer 260. The capping layer 260 may be disposed on the color filter CF. For example, the capping layer 260 may cover the upper horizontal structure Pc on the color filter CF, and the space between the color filters CF may be sealed. The sealed space may be referred to as an air gap AG. For example, the grid structure 250 may include an air gap AG therein. The lower end of the capping layer 260 may be disposed at a height higher than the lower surface of the color filter CF. The capping layer 260 may not be in direct contact with the color filter CF, and may be arranged to be spaced apart from the color filter CF, and the protective layer P is between the capping layer 260 and the color filter CF. The capping layer 260 may include a material different from the protective layer P. In one or more example embodiments, the capping layer 260 may include a transparent insulating material. For example, the capping layer 260 may include an organic material.

[0081] The lower horizontal structure Pb, the vertical structure Pa and the capping layer 260 may define an air gap AG, that is, the lower horizontal structure Pb, the vertical structure Pa and the capping layer 260 are arranged around the air gap. The upper limit of the air gap AG may be defined by the capping layer 260, the lateral limit of the air gap AG may be defined by the vertical structure Pa, and the lower limit of the air gap AG may be defined by the lower horizontal structure Pb. Since the grid structure has an air gap AG with a refractive index of 1 inside, the optical crosstalk of the image sensor 1 may be prevented or reduced. In the top view, the air gap AG may extend horizontally along the grid structure 250 between the color filters CF.

[0082] Among the plurality of color filters CF, four color filters CF adjacent to each other may be respectively referred to as a first color filter CF1, a second color filter CF2, a third color filter CF3, and a fourth color filter CF4. The second color filter CF2 may be spaced apart from the first color filter CF1 in the X direction, and may be spaced apart from the third color filter CF3 in the Y direction. The fourth color filter CF4 may be spaced apart from the first color filter CF1 in the Y direction, and may be spaced apart from the third color filter CF3 in the X direction.

[0083] Figure 6 yes Figure 5 A magnified view of the image sensor is shown.

[0084] Further references Figure 6 , the grid structure 250 may be disposed between two adjacent color filters CF, for example, between the first color filter CF1 and the second color filter CF2. The capping layer 260 may cover the grid structure 250. The capping layer 260 may include a first portion 261 and a second portion 262. For example, the portion of the capping layer 260 that vertically overlaps the color filter CF may be referred to as the first portion 261. The portion of the capping layer 260 that is disposed between two adjacent color filters CF and does not vertically overlap the color filter CF may be referred to as the second portion 262. In some embodiments, the upper surface and the lower surface of the second portion 262 may be convex or concave, respectively. In one or more example embodiments, the upper surface and the lower surface of the second portion 262 may each be flat. In some embodiments, at least a portion of the lower surface of the second portion 262 may be located at a different height from the lower surface of the first portion 261. In some embodiments, at least a portion of the upper surface of the second portion 262 may be located at a different height from the upper surface of the first portion 261.

[0085] The lower surface of the first portion 261 may be located at a first vertical height LV1, and the upper surface of the first portion 261 may be located at a second vertical height LV2. In one or more example embodiments, the second portion 262 of the capping layer 260 may be shifted to be lower than the first portion 261, and the upper and lower surfaces of the second portion 262 may be convex downward. For example, the lower end of the second portion 262 of the capping layer 260 may be located at a height lower than the lower end of the first portion 261. For example, the lower end of the lower surface of the second portion 262 may be located at a third vertical height LV3, and the third vertical height LV3 may be lower than the first vertical height LV1. In one or more example embodiments, the lower end of the upper surface of the second portion 262 of the capping layer 260 may be located at a fourth vertical height LV4, and the fourth vertical height LV4 may be lower than the second vertical height LV2.

[0086] In one or more example embodiments, the thickness T1 of the first portion 261 may be the same as the thickness T2 of the second portion 262 , but is not limited thereto.

[0087] Figure 7 is along Figure 4 The vertical cross-sectional view of the image sensor shown is taken along line II-II'. For ease of explanation, Figure 7 Components are shown disposed on an insulating structure 240, similar to Figure 6 .

[0088] refer to Figure 7 , the capping layer 260 may further include a third portion 263. The third portion 263 may refer to a portion of the capping layer 260 disposed between four adjacent color filters CF (e.g., between the first color filter CF1 and the third color filter CF3). In some embodiments, a portion of the lower surface of the third portion 263 may be located at a different height from the lower surface of the second portion 262. In some embodiments, a portion of the upper surface of the third portion 263 may be located at a different height from the upper surface of the second portion 262.

[0089] In one or more example embodiments, the third portion 263 of the capping layer 260 may be shifted to be lower than the second portion 262, and the upper and lower surfaces of the third portion 263 may bulge downward. For example, the lower end of the third portion 263 of the capping layer 260 may be located at a height lower than the lower end of the second portion 262. For example, the lower end of the lower surface of the third portion 263 may be located at a fifth vertical height LV5, and the fifth vertical height (LV5) may be lower than the third vertical height LV3. In one or more example embodiments, the lower end of the upper surface of the third portion 263 of the capping layer 260 may be located at a sixth vertical height LV6, and the sixth vertical height LV6 may be lower than the fourth vertical height LV4. The structural features of the lower surface of the third portion 263 of the capping layer 260 described above may also be applied to the reference structure described later. Figures 13 to 15 ,as well as Fig.18 Described embodiments.

[0090] In one or more example embodiments, the thickness T3 of the third portion 263 may be the same as the thickness T2 of the second portion 262 , but is not limited thereto.

[0091] The second chip structure 203 may further include a microlens ML on the capping layer 260 .

[0092] The microlens ML may overlap vertically with each color filter CF. In one or more example embodiments, the microlenses ML may each overlap vertically with the color filter CF. Alternatively, the microlens ML may overlap vertically with each of the plurality of color filters CF. For example, one microlens among the microlenses ML may overlap vertically with four adjacent color filters CF among the plurality of color filters CF.

[0093] Each microlens ML may have a convex shape in a direction away from the first chip structure 103. The microlens ML may converge incident light into the photoelectric conversion element PD. The microlens ML may be formed of a transparent photoresist material or a transparent thermosetting resin material. For example, the microlens ML may be formed of a TMR series resin (produced by Tokyo Ohka Kogo, Co.) or an MFR series resin (produced by Japan Synthetic Rubber Corporation), but one or more example embodiments are not limited to these substances.

[0094] Figure 8 , Fig. 9 , Fig.10 , Fig.11 and Fig.12 1 is a plan view and a cross-sectional view shown in process order to describe a method of manufacturing an image sensor according to one or more example embodiments. In detail, Figure 8 , Fig. 9 , Fig.10 , Fig.11 and Fig.12 They correspond to Figure 5 Vertical cross-section of .

[0095] refer to Figure 8 , a color filter CF may be formed on the insulating structure 240. The color filter CF may be arranged to vertically overlap the photoelectric conversion element PD. The color filter CF may be arranged to be spaced apart from each other in the X direction and the Y direction.

[0096] refer to Fig. 9 , a protection layer P may be formed. The protection layer P may cover the insulating structure 240 and the color filter CF. For example, the protection layer P may be conformally formed along the surfaces of the insulating structure 240 and the color filter CF.

[0097] refer to Fig.10 , a photoresist PR and a mask layer M may be formed on the protective layer P. The photoresist PR may cover the protective layer P, and a portion of the photoresist PR may be disposed between the color filters CF. The mask layer M may be disposed on the photoresist PR. The mask layer M may be patterned to expose a portion of the photoresist PR vertically overlapping the separation structure 215.

[0098] refer to Fig.11, an etching process may be performed using the mask layer M as an etching mask, and the photoresist PR may be patterned to form a photoresist pattern PRP. For example, a portion of the photoresist PR exposed by the mask layer M may be removed. The photoresist pattern PRP may be disposed on each color filter CF and may be disposed to be spaced apart from each other. After the etching process is performed, the mask layer M may be removed.

[0099] refer to Fig.12 , a reflow process may be performed. For example, the photoresist pattern PRP may be heated and melted. The photoresist pattern PRP disposed on the color filter CF may be melted by heat and extend between the color filters CF to be combined with each other. The combined photoresist pattern PRP may be referred to as a capping layer 260.

[0100] The capping layer 260 may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. The second portion 262 may be formed by bonding adjacent photoresist patterns PRP together. In one or more example embodiments, the lower end of the second portion 262 may be located at a height lower than the lower surface of the first portion 261. However, the shape of the second portion 262 may vary depending on the viscosity and thickness of the capping layer 260, reflow process conditions, and the like.

[0101] Reference again Figure 5 , the image sensor 1 may be manufactured by forming a microlens (ML) on the capping layer 260 .

[0102] Fig.13 is a vertical cross-sectional view of an image sensor according to one or more example embodiments.

[0103] refer to Fig.13 , the image sensor 1a may include a capping layer 260 disposed on the grid structure 250 and the color filter CF. In one or more example embodiments, the image sensor 1a may further include the capping layer 260 and a planarization layer 270 disposed on the microlens ML. The planarization layer 270 may cover the upper surface of the capping layer 260. The planarization layer 270 may include an inorganic material (e.g., silicon oxide, silicon nitride, and silicon oxynitride) or an organic material.

[0104] Figures 14 to 20 is a vertical cross-sectional view of an image sensor according to one or more example embodiments.

[0105] refer to Fig.14, the image sensor 1b may include a grid structure 250 and a capping layer 260 disposed on the color filter CF. The capping layer 260 may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, a thickness T2 of the second portion 262 may be less than a thickness T1 of the first portion 261.

[0106] refer to Fig.15 , the capping layer 260 of the image sensor 1c may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two color filters CF adjacent to each other. In one or more example embodiments, the upper surface of the second portion 262 may be coplanar with the upper surface of the first portion 261, and may be located at the same height. For example, the upper surface of the second portion 262 and the upper surface of the first portion 261 may be located at a second vertical height LV2. The lower end of the second portion 262 may be located at a height lower than the lower surface of the first portion 261. For example, the lower end of the second portion 262 may be located at a third vertical height LV3 lower than the first vertical height LV1. In one or more example embodiments, the thickness T2 of the second portion 262 may be greater than the thickness T1 of the first portion 261.

[0107] refer to Fig.16 , the capping layer 260 of the image sensor 1d may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, the second portion 262 of the capping layer 260 may be shifted above the first portion 261, and the upper and lower surfaces of the second portion 262 may bulge upward. For example, the upper end of the second portion 262 of the capping layer 260 may be located at a height higher than the upper surface of the first portion 261. For example, the upper end of the lower surface of the second portion 262 may be located at a third vertical height LV3, and the third vertical height LV3 may be higher than the first vertical height LV1. In one or more example embodiments, the upper end of the upper surface of the second portion 262 of the capping layer 260 may be located at a fourth vertical height LV4, and the fourth vertical height LV4 may be higher than the second vertical height LV2. The upper end of the air gap AG may be located at a height higher than the upper surface of the color filter CF.

[0108] The capping layer 260 may further include a third portion 263 disposed between four adjacent color filters CF. In one or more example embodiments, the third portion 263 of the capping layer 260 may be shifted above the second portion 262, and the upper and lower surfaces of the third portion 263 may bulge upward. For example, the upper end of the third portion 263 of the capping layer 260 may be located at a height higher than the upper end of the second portion 262. For example, the upper end of the lower surface of the third portion 263 may be located at a fifth vertical height LV5, and the fifth vertical height LV5 may be higher than the third vertical height LV3. In one or more example embodiments, the upper end of the upper surface of the third portion 263 of the capping layer 260 may be located at a sixth vertical height LV6, and the sixth vertical height (LV6) may be higher than the fourth vertical height LV4. In one or more example embodiments, the thickness T3 of the third portion 263 may be greater than or equal to the thickness T2 of the second portion 262. The structural features of the upper surface of the third portion 263 of the capping layer 260 described above may also be applied to the reference numerals described later. Fig.17 and Fig.18 Described embodiments.

[0109] refer to Fig.17 , the capping layer 260 of the image sensor 1e may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, the lower surface of the second portion 262 may be coplanar with the lower surface of the first portion 261, and may be located at the same height. For example, the lower surface of the second portion 262 and the lower surface of the first portion 261 may be located at a first vertical height LV1. The upper end of the upper surface of the second portion 262 may be located at a height higher than the upper surface of the first portion 261. For example, the upper end of the upper surface of the second portion 262 may be located at a fourth vertical height LV4 that is higher than the second vertical height LV2. In one or more example embodiments, the thickness T2 of the second portion 262 may be greater than the thickness T1 of the first portion 261.

[0110] refer to Fig.18 , the capping layer 260 of the image sensor 1f may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, the upper surface of the second portion 262 may bulge upward, and the lower surface of the second portion 262 may bulge downward. The lower end of the lower surface of the second portion 262 may be located at a third vertical height LV3 lower than the first vertical height LV1, and the upper end of the upper surface of the second portion 262 may be located at a fourth vertical height LV4 higher than the second vertical height LV2. In one or more example embodiments, the thickness T2 of the second portion 262 may be greater than the thickness T1 of the first portion 261.

[0111] The capping layer 260 may further include a third portion 263 disposed between four adjacent color filters CF. In one or more example embodiments, the upper surface of the third portion 263 may bulge upward, and the lower surface of the third portion 263 may bulge downward. In one or more example embodiments, the thickness T3 of the third portion 263 may be greater than the thickness T2 of the second portion 262.

[0112] refer to Fig.19 , the capping layer 260 of the image sensor 1g may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, the upper surface of the second portion 262 may be coplanar with the upper surface of the first portion 261, and may be located at the same height. For example, the upper surface of the second portion 262 and the upper surface of the first portion 261 may be located at a second vertical height LV2. The upper end of the lower surface of the second portion 262 may be located at a height higher than the lower surface of the first portion 261. For example, the upper end of the lower surface of the second portion 262 may be located at a third vertical height LV3 higher than the first vertical height LV1. In one or more example embodiments, the thickness T2 of the second portion 262 may be less than the thickness T1 of the first portion 261.

[0113] refer to Fig. 20 , the capping layer 260 of the image sensor 1h may include a first portion 261 vertically overlapping the color filter CF, and a second portion 262 disposed between two adjacent color filters CF. In one or more example embodiments, a thickness T2 of the second portion 262 may be equal to a thickness T1 of the first portion 261. For example, a lower surface and an upper surface of the second portion 262 may be flat and may be located at a first vertical height LV1 and a second vertical height LV2, respectively.

[0114] As described above, according to one or more example embodiments, since the grid structure includes the air gap, optical crosstalk may be prevented or reduced.

[0115] Although one or more example embodiments have been particularly shown and described above, it will be apparent to those skilled in the art that modifications and changes in form and details may be made therein without departing from the spirit and scope of the appended claims.

Claims

1. An image sensor, comprising: A photoelectric conversion element, within the substrate; a separation structure within the substrate and between the photoelectric conversion elements; an insulating structure on the substrate and the separation structure; a plurality of color filters on the insulating structure; a grid structure including a lower horizontal structure disposed on the insulating structure, and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters; an upper horizontal structure covering an upper surface of the plurality of color filters; as well as a capping layer, covering the upper horizontal structure and the grid structure, Wherein, the grid structure further comprises an air gap, and wherein the vertical structure, the lower horizontal structure and the capping layer are all arranged around the air gap.

2. The image sensor according to claim 1, wherein: The upper limit of the air gap is defined by the capping layer.

3. The image sensor according to claim 1, wherein: The upper horizontal structure extends from the vertical structure of the grid structure.

4. The image sensor according to claim 1, wherein: The grid structure and the upper horizontal structure each have a thickness of 3 nm to 200 nm.

5. The image sensor according to claim 1, wherein: The plurality of color filters are spaced apart from each other.

6. The image sensor according to claim 1, wherein: The capping layer is spaced apart from the plurality of color filters, and the upper horizontal structure is interposed between the capping layer and the plurality of color filters.

7. The image sensor according to claim 1, wherein: The capping layer includes a material different from that of the upper horizontal structure.

8. The image sensor according to claim 1, in, The plurality of color filters include a first color filter and a second color filter adjacent to each other in a first horizontal direction, wherein the capping layer includes a first portion vertically overlapping the first color filter and a second portion between the first color filter and the second color filter, and The second portion defines an upper limit of the air gap.

9. The image sensor according to claim 8, wherein: At least a portion of the lower surface of the second portion is at a different height than the lower surface of the first portion.

10. The image sensor according to claim 8, wherein: At least a portion of an upper surface of the second portion is at a different height than an upper surface of the first portion.

11. The image sensor according to claim 8, wherein: The thickness of the second portion is greater than or equal to the thickness of the first portion.

12. The image sensor according to claim 8, wherein: The lower surface of the second portion is a convex surface or a concave surface.

13. The image sensor according to claim 8, in, The plurality of color filters further include a third color filter adjacent to the second color filter in a second horizontal direction intersecting the first horizontal direction, The capping layer further includes a third portion disposed between the first color filter and the third color filter, and Wherein, at least a portion of the lower surface of the third portion is at a different height than the lower surface of the second portion.

14. The image sensor according to claim 13, wherein: The thickness of the third portion is different from the thickness of the second portion. 15 . The image sensor according to claim 1 , further comprising a planarization layer disposed on the capping layer.

16. An image sensor, comprising: A photoelectric conversion element, within the substrate; a separation structure within the substrate and between the photoelectric conversion elements; an insulating structure on the substrate and the separation structure; a plurality of color filters on the insulating structure; a protective layer, covering the insulating structure and the plurality of color filters; as well as a capping layer covering the protective layer, wherein the lower end of the capping layer is at a height higher than the lower surfaces of the plurality of color filters, and The protection layer and the capping layer define air gaps between the plurality of color filters.

17. The image sensor according to claim 16, wherein: The protection layer includes a lower horizontal structure disposed on the insulating structure, a vertical structure extending from the lower horizontal structure and covering side surfaces of the plurality of color filters, and an upper horizontal structure extending from the vertical structure and upper surfaces of the plurality of color filters.

18. The image sensor according to claim 17, wherein: In a plan view, the plurality of color filters are respectively surrounded by the vertical structures.

19. The image sensor according to claim 17, wherein: In plan view, the air gap extends horizontally between the vertical structures.

20. An image sensor, comprising: The lower chip includes the logic circuit; as well as an upper chip on the lower chip, the upper chip being bonded to the lower chip, Wherein, the upper chip comprises: A photoelectric conversion element is disposed in the substrate; A separation structure disposed in the substrate and between the photoelectric conversion elements; An insulating structure, disposed on the substrate and the separation structure; a plurality of color filters disposed on the insulating structure and spaced apart from each other; a grid structure disposed between the plurality of color filters, the grid structure comprising a lower horizontal structure disposed on the insulating structure, and a vertical structure connected to the lower horizontal structure and covering a side surface of one of the plurality of color filters; an upper horizontal structure covering an upper surface of the plurality of color filters; a capping layer covering the upper horizontal structure and the grid structure; and A microlens is disposed on the capping layer, Wherein, the grid structure includes an air gap, and the air gap is surrounded by the vertical structure, the lower horizontal structure and the capping layer.

Images