Image sensor

Abstract

An image sensor is provided. The image sensor comprises: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; a plurality of color filters disposed on the insulating structure; and a grid structure disposed on the insulating structure, with at least a portion disposed between the plurality of color filters. The plurality of color filters includes a first color filter and a second color filter of different colors, and the insulating structure includes a first region having a first thickness and a second region having a second thickness different from the first thickness, and the boundary region between the first region and the second region in the insulating structure overlaps perpendicularly with the first color filter and is misaligned with the vertical center axis of the grid structure.

Description

Technology Field

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

[0003] Image sensors, which capture images and convert them into electrical signals, are used not only in general consumer electronic devices such as digital cameras, mobile phone cameras, and portable camcorders, but also in cameras mounted on automobiles, security devices, and robots. As these image sensors require miniaturization and high resolution, various studies are being conducted to meet these requirements. The problem to be solved

[0005] One of the technical problems that the technical concept of the present invention aims to solve is to provide an image sensor capable of increasing sensitivity. means of solving the problem

[0007] An image sensor according to one embodiment of the technical concept of the present invention is provided. The image sensor comprises: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; a plurality of color filters disposed on the insulating structure; and a grid structure disposed on the insulating structure, with at least a portion disposed between the plurality of color filters. The plurality of color filters includes a first color filter and a second color filter of different colors, and the insulating structure includes a first region having a first thickness and a second region having a second thickness different from the first thickness, and the boundary region between the first region and the second region in the insulating structure overlaps perpendicularly with the first color filter and is misaligned with the vertical center axis of the grid structure.

[0008] An image sensor according to one embodiment of the technical concept of the present invention is provided. The image sensor comprises: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; and a plurality of color filters disposed on the insulating structure. The plurality of color filters includes a first color filter and a second color filter of different colors, and the insulating structure includes a lower layer, an intermediate layer, and an upper layer stacked in sequence, wherein the lower layer has a substantially uniform thickness, the upper layer has a substantially uniform thickness, and the intermediate layer includes two or more regions having different thicknesses.

[0009] An image sensor according to one embodiment of the technical concept of the present invention is provided. The image sensor comprises: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a separation structure disposed between the photodiodes within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; a plurality of color filters disposed on the insulating structure; and a grid structure disposed on the insulating structure, with at least a portion disposed between the plurality of color filters. At least a portion of the grid structure is vertically superimposed with at least a portion of the separation structure, and the plurality of color filters include a blue color filter, a green color filter, and a red color filter of different colors, and the insulating structure includes a lower layer, an intermediate layer, and an upper layer stacked in sequence, the lower layer has a substantially uniform thickness, the upper layer has a substantially uniform thickness, and the intermediate layer includes two or more regions having different thicknesses, and the minimum thickness of the insulating structure superimposed with the blue color filter is smaller than the maximum thickness of the insulating structure superimposed with the red color filter, and the lower surface of the grid structure is positioned at a constant height level. Effects of the invention

[0011] According to embodiments of the technical concept of the present invention, an insulating structure that may include an anti-reflection layer may include a plurality of layers, and among the plurality of layers, an intermediate layer may include two or more regions having different thicknesses. An insulating structure including an intermediate layer having two or more regions having different thicknesses in this way can improve the transmittance of light passing through the insulating structure through color filters, thereby improving the sensitivity of an image sensor.

[0012] The various and beneficial advantages and effects of the present invention are not limited to those described above and will be more easily understood in the process of explaining specific embodiments of the present invention. Brief explanation of the drawing

[0014] FIG. 1 is a schematic top view showing an image sensor according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of an image sensor according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a modified example of an image sensor according to one embodiment of the present invention. FIG. 4a is a schematic cross-sectional view showing a modified example of an image sensor according to one embodiment of the present invention. FIG. 4b is a schematic cross-sectional view showing a modified example of an image sensor according to one embodiment of the present invention. FIG. 4c is a schematic cross-sectional view showing a modified example of an image sensor according to one embodiment of the present invention. FIG. 4d is a schematic cross-sectional view showing a modified example of an image sensor according to one embodiment of the present invention. FIG. 5 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 7 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 8a is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 8b is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 9a is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 9b is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 10 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 12 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 13 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 14 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 15 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 16 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 17 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 18a is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 18b is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 19 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 20 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 21 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 22 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 23 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 24 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 25 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 26 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 27 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 28 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 29 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 30 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 31 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 32 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 33 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 34 is a schematic cross-sectional view showing a modified example of an image sensor according to another embodiment of the present invention. FIG. 35 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 36 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 37 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 38 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 39 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 40 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 41 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 42 is a schematic cross-sectional view showing an example of an image sensor according to another embodiment of the present invention. FIG. 43 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 44 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIG. 45 is a schematic top view showing an image sensor according to another embodiment of the present invention. FIGS. 46 and FIGS. 47 are graphs showing the characteristics of an image sensor according to one embodiment of the present invention. FIG. 48 is a process flow diagram showing a method for forming an image sensor according to embodiments of the present invention. FIGS. 49, FIGS. 50a to 50c are drawings illustrating an example of an image sensor forming method according to embodiments of the present invention. FIGS. 51, FIGS. 52a to 52c are drawings illustrating other examples of an image sensor forming method according to embodiments of the present invention. Specific details for implementing the invention

[0015] In the following, terms such as 'top', 'upper part', 'upper surface', 'lower', 'lower part', 'lower surface', 'side surface', 'top', and 'bottom' may be understood as referring to the drawings, except where otherwise indicated by drawing symbols.

[0016] First, with reference to FIGS. 1 and FIGS. 2, an example of an image sensor according to an embodiment of the present invention will be described. FIGS. 1 is a top view schematically showing an image sensor according to an embodiment of the present invention, and FIGS. 2 is a schematic cross-sectional view showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIGS. 1 to explain an example of an image sensor according to an embodiment of the present invention.

[0017] Referring to FIGS. 1 and 2, the image sensor (1a) may include a first chip structure (3) and a second chip structure (103) on the first chip structure (3). The first chip structure (3) may be a logic chip, and the second chip structure (103) may be an image sensor chip. In another example, the first chip structure (3) may be a stacked chip structure including a logic chip and a memory chip.

[0018] The first chip structure (3) of the image sensor (1a) may include a first substrate (6), a device isolation film (9s) defining an active region (9a) on the first substrate (6), a first circuit element (12) and a first wiring structure (15) on the first substrate (6), and a first insulating layer (18) covering the first circuit element (12) and the first wiring structure (15) on the first substrate (6).

[0019] The first substrate (6) may be a semiconductor substrate. For example, the first substrate (6) may be a substrate formed of a semiconductor material, for example, a single-crystal silicon substrate. The first circuit element (12) may include an element such as a transistor including a gate (12a) and a source / drain (12b).

[0020] The second chip structure (103) may include a second substrate (106) having a first surface (106s1) and a second surface (106s2) facing each other, a device isolation film (118) disposed on the first surface (106s1) of the second substrate (106) and defining an active region, a second circuit element (124) and a second wiring structure (127) disposed between the first surface (106s1) of the second substrate (106) and the first chip structure (3), and a second insulating layer (130) covering the second circuit element (124) and the second wiring structure (127) between the first surface (106s1) of the second substrate (106) and the first chip structure (3). The first surface (106s1) of the second substrate (106) may face the first chip structure (3).

[0021] The second substrate (106) may be a semiconductor substrate. For example, the second substrate (106) may be a substrate formed of a semiconductor material, for example, a single-crystal silicon substrate.

[0022] The image sensor (1a) may further include photoelectric conversion elements (PDs). The photoelectric conversion elements (PDs) can generate and accumulate charges corresponding to incident light. For example, the photoelectric conversion elements (PDs) may include photodiodes, phototransistors, photogates, pinned photodiodes (PPDs), and combinations thereof.

[0023] The above photoelectric conversion elements (PD) can be formed inside the second substrate (106) and can be spaced apart from each other.

[0024] The second chip structure (103) may further include a separation structure (115). The separation structure (115) may be positioned to surround each of the photoelectric conversion elements (PD). The separation structure (115) may be positioned within an opening (112) penetrating the second substrate (106).

[0025] The above separation structure (115) can penetrate the second substrate (106). The opening (112) can be connected to the device isolation film (118). Thus, the separation structure (115) can be connected to the device isolation film (118). The device isolation film (118) can be formed of an insulating material such as silicon oxide. The separation structure (115) may include a separation pattern (115b) and a separation insulating layer (115a) covering the side of the separation pattern (115b). For example, the separation insulating layer (115a) may include silicon oxide, and the separation pattern (115b) may include polysilicon.

[0026] The second circuit element (124) may include a transfer gate (TG) and active elements (121). The active elements (121) may be transistors including a gate (121a) and a source / drain (121b). The transfer gate (TG) may transfer charge from an adjacent photoelectric conversion element (PD) to an adjacent floating diffusion region, and the active elements (121) may be at least one of a source follower transistor, a reset transistor, and a select transistor.

[0027] The above transfer gate (TG) may be a vertical transfer gate including a portion extending from the first surface (106s1) of the second substrate (106) into the interior of the second substrate (106).

[0028] The second wiring structure (127) may include multilayer wiring located at different height levels and vias that electrically connect the multilayer wiring and electrically connect the multilayer wiring to the second circuit element (124).

[0029] The first insulating layer (18) and the second insulating layer (130) may be in contact and bonded. Each of the first and second insulating layers (18, 130) may be formed as a multilayer comprising different types of insulating layers. For example, the second insulating layer (130) may be formed as a multilayer comprising at least two types of silicon oxide layer, low dielectric layer, and silicon nitride layer.

[0030] The second chip structure (103) may further include an insulating structure (132a) disposed on the second surface (106s2) of the second substrate (106). The insulating structure (132a) may cover the separation structure (115).

[0031] The second chip structure (103) may include the grid structure (160). The grid structure (160) may be placed on the insulating structure (132a).

[0032] The grid structure (160) may include a first layer (162a) and a second layer (162b) stacked in sequence. The first layer (162a) may be in contact with the insulating structure (132). The thickness of the second layer (162b) may be greater than the thickness of the first layer (162a).

[0033] The first layer (162a) may include a first material, and the second layer (162b) may include a second material different from the first material.

[0034] In one example, the first material of the first layer (162a) may include a conductive material. For example, the first layer (162a) may be formed of a conductive material comprising at least one of a metal or a metal nitride. For example, the first layer (162a) may include at least one of Ti, Ta, TiN, TaN, or W.

[0035] In one example, the second material of the second layer (162b) may include an insulating material. The second material of the second layer (162b) may be a low refractive index (LRI) material. For example, the second layer (162b) may have a refractive index in the range of about 1.1 to about 1.8. The second layer (162b) may include an oxide or nitride comprising Si, Al, or a combination thereof. For example, the second layer (162b) may include silicon oxide with a porous structure or silica nanoparticles with a network structure.

[0036] The first layer (162a), formed of a conductive material, can serve as a charge path for removing charge, and the second layer (162b) can be formed of a low refractive index (LRI) material without including a conductive material that can reduce sensitivity in pixel regions, thereby improving the optical cross-talk phenomenon of the image sensor (1a).

[0037] The second chip structure (103) may further include the color filters (170), which include first to third color filters (170a, 170b, 170c). The color filters (170) may include first color filters (170a) of a first color, second color filters (170b) of a second color different from the first color, and third color filters (170c) of a third color different from the first and second colors. For example, the first color filters (170a) may be blue color filters, the second color filters (170b) may be green color filters, and the third color filters (170c) may be red color filters.

[0038] The color filters (170) may be placed on the insulating structure (132a). The color filters (170) may allow light of a specific wavelength to pass through and reach the photoelectric conversion elements (PD). For example, the color filters (170) may be formed from a material in which a pigment containing a metal or a metal oxide is mixed with a resin. The thickness of each of the color filters (170) may be greater than the thickness of the grid structure (160). The color filters (170) may cover the grid structure (160) on the insulating structure (132a). The color filters (170) may cover the side and top surfaces of the grid structure (160) on the insulating structure (132a).

[0039] In one example, the grid structure (160) may be placed between filters of different colors among the first to third color filters (170a, 170b, 170c).

[0040] In one example, the grid structure (160) can be vertically superimposed with the separation structure (115).

[0041] In one example, the grid structure (160) may have a different width from the separation structure (115). For example, the width of the grid structure (160) may be greater than the width of the separation structure (115).

[0042] The second chip structure (103) may further include micro-lenses (180) on the color filters (170). Each of the micro-lenses (180) may overlap with each of the photoelectric conversion elements (PD). Each of the micro-lenses (180) may be convex in a direction away from the first chip structure (3). The micro-lenses (180) may focus incident light into the photoelectric conversion elements (PD). The micro-lenses (180) may be formed of a transparent photoresist material or a transparent thermosetting resin material. For example, the micro-lenses (180) may be formed of a TMR-based resin (product of Tokyo Ohka Kogo, Co.) or an MFR-based resin (product of Japan Synthetic Rubber Corporation), but are not limited to these materials.

[0044] The insulating structure (132a) may include an anti-reflection layer capable of preventing light reflection that may occur due to a sudden change in refractive index on the second surface (106s2) of the second substrate (106), which may be formed of silicon. For example, the insulating structure (132a) may include a plurality of layers stacked in sequence. The insulating structure (132a) may include an anti-reflection layer capable of controlling the refractive index to allow incident light to proceed to the photoelectric conversion elements (PDs) with high transmittance. For example, the insulating structure (132a) may include at least three layers. Accordingly, the insulating structure (132a) may also be referred to as an anti-reflection structure.

[0045] In one example, the insulating structure (132a) may include a lower layer (134), an intermediate layer (136a, 142a) on the lower layer (134), and an upper layer (148) on the intermediate layer (136a, 142a).

[0046] The lower layer (134) may be in contact with the second surface (106s2) of the substrate (106). The lower layer (134) may be permeable in a visible wavelength and may include a material having a negative charge to prevent charge caused by dangling bonds of the second surface (106s2) of the substrate (106). The intermediate layer (136a, 142a) may be permeable in a visible wavelength and may include a material capable of controlling the peak of transmittance by adjusting the thickness. The upper layer (148) may be permeable in a visible wavelength and may include a material capable of passivating the intermediate layer (136a, 142a).

[0047] The lower layer (134) may include a material having a first refractive index, for example, a material with a refractive index of about 2, the intermediate layer (136a, 142a) may include a material having a second refractive index smaller than the first refractive index, for example, a material with a refractive index of about 1.5, and the upper layer (148) may include a material having a refractive index larger than the second refractive index, for example, a material with a refractive index of about 2.

[0048] The lower layer (134) may include a high-k dielectric, for example, aluminum oxide.

[0049] The above intermediate layers (136a, 142a) may include a first intermediate layer (136a) and a second intermediate layer (142a) stacked in sequence.

[0050] The first intermediate layer (136a) may include a material different from the material of the lower layer (134) and the material of the second intermediate layer (142a). For example, the first intermediate layer (136a) may include a high dielectric material different from the material of the lower layer (134). For example, the first intermediate layer (136a) may include hafnium oxide. The second intermediate layer (142a) may include silicon oxide.

[0051] The thickness of the first intermediate layer (136a) may be greater than the thickness of the lower layer (134).

[0052] The upper layer (148) may include at least one material layer. For example, the upper layer (148) may include a first layer (150a) and a second layer (150b) stacked in sequence. For example, in the upper layer (148), the first layer (150a) may include a hafnium oxide layer, and the second layer (150b) may include an aluminum oxide layer.

[0053] The first layer (150a) of the upper layer (148) may be formed of the same material as the first intermediate layer (136a), for example, hafnium oxide. The second layer (150b) of the upper layer (148) may be formed of the same material as the lower layer (134), for example, aluminum oxide. The second layer (150b) of the upper layer (148) may have substantially the same thickness as the lower layer (134). The second layer (150b) of the upper layer (148) may be in contact with the color filters (170) and the grid structure (160).

[0054] The insulating structure (132a) may include a first region (132A) having a first thickness and a second region (132B) having a second thickness different from the first thickness. The second thickness may be greater than the first thickness.

[0055] In the second region (132B) of the insulating structure (132a), the second intermediate layer (142a) may be formed by a first layer (144a) and a second layer (144b) stacked in sequence, and in the first region (132A) of the insulating structure (132a), the second intermediate layer (142a) may be formed by the second layer (144b). Accordingly, the second intermediate layer (142a) may include a thick portion formed by the first and second layers (144a, 144b) and a thin portion formed by the second layer (144b). Depending on the thickness difference according to the position of the second intermediate layer (142a), a thickness difference may occur between the first and second regions (132A, 132B) of the insulating structure (132a).

[0056] In the second intermediate layer (142a) above, the first layer (144a) and the second layer (144b) can be formed of the same material, for example, silicon oxide.

[0057] In the second intermediate layer (142a), the thickness of the maximum thickness portion, for example, the thick portion formed by the first and second layers (144a, 144b), may be greater than the thickness of the lower layer (134).

[0058] In the second intermediate layer (142a), the thickness of the maximum thickness portion, for example, the thick portion formed by the first and second layers (144a, 144b), may be greater than the thickness of the first intermediate layer (136a).

[0059] In the second intermediate layer (142a), the thickness of the thin portion formed by the minimum thickness portion, for example, the second layer (144b), may be greater than the thickness of the lower layer (134).

[0060] In the second intermediate layer (142a), the thickness of the thin portion formed by the minimum thickness portion, for example, the second layer (144b), may differ from the thickness of the first intermediate layer (136a). In one example, in the second intermediate layer (142a), the thickness of the thin portion formed by the minimum thickness portion, for example, the second layer (144b), may be smaller than the thickness of the first intermediate layer (136a). In another example, in the second intermediate layer (142a), the thickness of the thin portion formed by the minimum thickness portion, for example, the second layer (144b), may be larger than the thickness of the first intermediate layer (136a).

[0061] The grid structure (160) may be placed on the second region (132B) of the insulating structure (132a). The grid structure (160) may be in contact with the second region (132B) of the insulating structure (132a) and may be spaced apart from the first region (132A) of the insulating structure (132a). Accordingly, the lower surface of the grid structure (160) may be located at a certain height level when viewed with respect to the second surface (106s2) of the second substrate (106).

[0062] The second region (132B) of the insulating structure (132a) may come into contact with the second and third color filters (170b, 170c) and may come into contact with the edge portion of each of the first color filters (170a). The center portion of each of the first color filters (170a) may come into contact with the first region (132A) of the insulating structure (132a). In each of the first color filters (170a), the edge portion may be shaped to surround the center portion.

[0063] The second region (132B) of the insulating structure (132a) can be vertically overlapped with the edge portions of each of the first color filters (170a), the second and third color filters (170b, 170c), and the grid structure (160), and the first region (132A) of the insulating structure (132a) can be vertically overlapped with the center portions of each of the first color filters (170a).

[0064] The region of thickness change in the insulating structure (132a), that is, the boundary region (132br) between the first region (132A) and the second region (132B), may overlap perpendicularly with the first color filters (170a), may be spaced apart from the sides of the first color filters (170a), and may be spaced apart from the grid structure (160). The boundary region (132br) between the first region (132A) and the second region (132B) in the insulating structure (132a) may overlap perpendicularly with at least a portion of the first color filter (170a) and may be misaligned with the vertical center axis of the grid structure (160).

[0065] In the top view, the boundary area (132br) between the first area (132A) and the second area (132B) may be described as the boundary area between the center portion and the edge portion in each of the first color filters (170a).

[0066] In each of the first color filters (170a), the lower surface of the center portion may be positioned at a lower level than the lower surface of the edge portion. The lower surface of the center portion of each of the first color filters (170a), the lower surfaces of the second color filters (170b), the lower surfaces of the third color filters (170c), and the lower surface of the grid structure (160) may be positioned at substantially the same level.

[0068] The image sensor (1a) including the insulating structure (132a) described above can optimize the transmittance of light passing through the first color filters, i.e., the blue color filter (170a), and the second color filters, i.e., the green color filter (170b). Accordingly, in the image sensor (1a) including the insulating structure (132a) described above, the transmittance of light passing through the insulating structure (132a) through the first color filters, i.e., the blue color filter (170a), and the second color filters, i.e., the green color filter (170b), can be improved, thereby improving the sensitivity of the image sensor (1a).

[0070] Next, with reference to FIG. 3, a modified example of the insulating structure (132a) will be described. In the following description, the modified example of the insulating structure (132a) will be described with a focus on the modified component or the replaced component. FIG. 3 is a schematic cross-sectional view showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIG. 1 to explain a modified example of an image sensor according to an embodiment of the present invention.

[0071] Referring to FIGS. 1 and FIGS. 3, an insulating structure (132b) of FIG. 3 that can replace the insulating structure (132a) of FIG. 2 may comprise a lower layer (134), intermediate layers (136b, 142b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (136b, 142b) may comprise a first intermediate layer (136b) and a second intermediate layer (142b) stacked in sequence. The first intermediate layer (136b) may comprise a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a of FIG. 2), and the second intermediate layer (142b) may comprise silicon oxide.

[0072] The insulating structure (132b) may include a first region (132A) having a first thickness and a second region (132B) having a second thickness greater than the first thickness, as described in FIG. 2.

[0073] In the second region (132B) of the insulating structure (132b), the first intermediate layer (136b) may be formed by a first layer (138a) and a second layer (138b) stacked in sequence, and in the first region (132A) of the insulating structure (132b), the first intermediate layer (136b) may be formed by the second layer (138b).

[0074] In one example, the first layer (138a) and the second layer (138b) of the first intermediate layer (136b) may each contain the same material, for example, hafnium oxide. In another example, the first layer (138a) and the second layer (138b) of the first intermediate layer (136b) may be formed of different materials.

[0075] The first intermediate layer (136b) may include a thick portion formed by the first and second layers (138a, 138b) and a thin portion formed by the second layer (138b). Depending on the thickness difference according to the position of the first intermediate layer (136b), a thickness difference may occur between the first and second regions (132A, 132B) of the insulating structure (132a).

[0076] According to embodiments, the image sensor (1a) may include the insulating structure (132a) in which the thickness of the first and second regions (132A, 132B) varies according to the thickness change of the second intermediate layer (142a) as described in FIG. 2, or the insulating structure (132b) in which the thickness of the first and second regions (132A, 132B) varies according to the thickness change of the first intermediate layer (136b) as described in FIG. 3. Accordingly, the image sensor (1a) may include an insulating structure (132a in FIG. 2 or 132b in FIG. 3) having a thickness optimized according to the wavelengths of the first and second color filters (170a, 170b), thereby improving the transmittance of light passing through the insulating structure (132a in FIG. 2 or 132b in FIG. 3) through the first and second color filters (170a, 170b), and thus improving the sensitivity of the image sensor (1a).

[0078] The separation structure (115) described in FIGS. 2 and 3 may be disposed within an opening (112) that penetrates from the first surface (106s1) of the second substrate (106) toward the second surface (106s2), but embodiments of the present invention are not limited thereto and may be modified in various ways. Additionally, the insulating structure (132a in FIG. 2 or 132b in FIG. 3) described in FIG. 2 and 3 may be modified so as to extend into the substrate (106). Hereinafter, various modified examples of the separation structure (115) and the insulating structure (132a in FIG. 2 and 132b in FIG. 3) will be described with reference to FIGS. 4a to 4d, respectively. FIGS. 4a to 4d are schematic cross-sectional views showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIG. 1 to illustrate various modified examples of an image sensor according to an embodiment of the present invention.

[0079] First, referring to FIG. 1 and FIG. 4a, the separation structure (115 in FIG. 2) in FIG. 2 can be modified into a separation structure (115') as in FIG. 4a. The separation structure (115') can be placed within an opening (112') extending in a direction from the second surface (106s2) of the second substrate (106) toward the first surface (106s1).

[0080] The above separation structure (115') may be spaced apart from the device isolation film (118). The above separation structure (115') extends in a direction from the second surface (106s2) of the second substrate (106) toward the first surface (106s1), and the end portion may be located inside the second substrate (106).

[0081] The insulating structure (132a in FIG. 2), comprising first and second regions (132A, 132B) of different thicknesses as described in FIG. 2, can be modified into an insulating structure (132ca) comprising at least one layer of material extending into the opening (112'). For example, at least a portion of the insulating structure (132a in FIG. 2) described in FIG. 2 may extend into the opening (112') to form the separating structure (115'). For example, the separation structure (115') may include a first layer (116a') and a second layer (116b') that sequentially cover the inner wall of the opening (112'), and a third layer (116c) that fills the opening (112') on the second layer (116b'), and the first to third layers (116a', 116b', 116c') may be formed by extending from at least a portion of the insulating structure (132ca).

[0082] In one example, the insulating structure (132ca) may include a lower layer (134'), an intermediate layer (136a', 142a'), and an upper layer (148) stacked in sequence. The intermediate layer (136a', 142a') may include a first intermediate layer (136a') and a second intermediate layer (142a') stacked in sequence. The second intermediate layer (142a') may include a first layer (144a') and a second layer (144b') stacked in sequence.

[0083] The lower layer (134'), the intermediate layer (136a', 142a'), and the upper layer (148) of the insulating structure (132a) described in FIG. 2 may correspond to the lower layer (134), the intermediate layer (136a, 142a), and the upper layer (148) of the insulating structure (132a) described in FIG. 2, respectively, and may be formed of the same material as the lower layer (134), the intermediate layer (136a, 142a), and the upper layer (148) of the insulating structure (132a) described in FIG. 2.

[0084] The lower layer (134') may extend into the opening (112') to form the first layer (116a') of the separation structure (115'), and a part of the intermediate layer (136a', 142a'), for example, the first intermediate layer (136a') may extend into the opening (112') to form the second layer (116b') of the separation structure (115'), and the first layer (144a') of the second intermediate layer (142a') may form the third layer (116c') of the separation structure (115').

[0085] The insulating structure (132ca) may include the first and second regions (132A, 132B) having different thicknesses as described in FIG. 2 on the second surface (106s2) of the substrate (106).

[0086] Next, referring to FIG. 1 and FIG. 4b, the separation structure (115 in FIG. 3) in FIG. 3 can be modified into a separation structure (115") as in FIG. 4b. The separation structure (115") can be placed within the opening (112') as described in FIG. 4a, which extends in a direction from the second surface (106s2) of the second substrate (106) toward the first surface (106s1).

[0087] The insulating structure (132b in FIG. 3) described in FIG. 3 may be modified into an insulating structure (132cb) comprising at least one layer of material extending into the opening (112'). For example, at least a portion of the insulating structure (132a in FIG. 2) described in FIG. 3 may extend into the opening (112') to form the separation structure (115"). For example, the separation structure (115") may include a first layer (116a"), a second layer (116b"), a third layer (116c"), and a fourth layer (116d") that sequentially cover the inner wall of the opening (112'), and the first to fourth layers (116a"), 116b"), 116c"), and 116d") may be formed by extending from at least a portion of the insulating structure (132cb).

[0088] In one example, the insulating structure (132cb) may include a lower layer (134'), an intermediate layer (136b', 142b'), and an upper layer (148) stacked in sequence. The intermediate layer (136b', 142b') may include a first intermediate layer (136b') and a second intermediate layer (142b') stacked in sequence. The first intermediate layer (136b') may include a first layer (138a') and a second layer (138b') stacked in sequence.

[0089] The lower layer (134'), the intermediate layer (138b', 142b'), and the upper layer (148) of the insulating structure (132cb) described in FIG. 3 may correspond to the lower layer (134), the intermediate layer (136b, 142b), and the upper layer (148) of the insulating structure (132b) described in FIG. 3, respectively, and may be formed of the same material as the lower layer (134), the intermediate layer (136b, 142b), and the upper layer (148) of the insulating structure (132b) described in FIG. 3.

[0090] The lower layer (134') may extend into the opening (112') to form the first layer (116a') of the separation structure (115"), and in the intermediate layer (136b', 142b'), the first layer (138a') and the second layer (138b') of the first intermediate layer (136b") may extend into the opening (112') to form the second layer (116b") and the third layer (116c") of the separation structure (115"), respectively, and the second intermediate layer (142b') may extend into the opening (112') to form the fourth layer (116d") of the separation structure (115").

[0091] The insulating structure (132cb) may include the first and second regions (132A, 132B) having different thicknesses as described in FIG. 3 on the second surface (106s2) of the substrate (106).

[0093] In FIGS. 2, FIGS. 3, FIGS. 4a, and FIGS. 4b, the second surface (106s2) of the second substrate (106) may be substantially flat, but embodiments of the present invention are not limited thereto. For example, in FIGS. 2, FIGS. 3, FIGS. 4a, and FIGS. 4b, the second surface (106s2) of the second substrate (106) may be deformed into a second surface having an uneven structure. Hereinafter, with reference to FIGS. 4c and FIGS. 4d, an example in which the second surface (106s2) of the second substrate (106) in FIGS. 4a and FIGS. 4b is deformed into a second surface having an uneven structure will be described. FIGS. 4c and FIGS. 4d are schematic cross-sectional views showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIG. 1 to explain an example of a deformed image sensor according to an embodiment of the present invention.

[0094] Referring to FIG. 1 and FIG. 4c, the second surface (106s2) of the second substrate (106) in FIG. 4a can be transformed into a second surface (106s2') having an uneven structure as in FIG. 4c. FIG. 4c illustrates an example in which the second surface (106s2 in FIG. 4a) of the second substrate (106) in FIG. 4a is transformed into the second surface (106s2') having an uneven structure, but the second surface (106s2) of the second substrate (106) in FIG. 2 can also be transformed into the second surface (106s2') having an uneven structure as in FIG. 4c. By forming the second surface (106s2') as an uneven structure, light transmittance can be improved. Thus, the sensitivity of the image sensor (1a) can be improved.

[0095] Referring to FIG. 1 and FIG. 4d, in order to improve the sensitivity of the image sensor (1a) as described in FIG. 4c, the second surface (106s2) of the second substrate (106) in FIG. 4b can be modified into a second surface (106s2') having an uneven structure as in FIG. 4d. Likewise, the second surface (106s2) of the second substrate (106) in FIG. 3 can also be modified into a second surface (106s2') having an uneven structure as in FIG. 4d.

[0097] Next, with reference to FIGS. 5 to 45, various modified examples of the image sensor (1a) described above will be explained. The various modified examples of the image sensor (1a) described below will be explained focusing on the modified or replaced components. In addition, various components that can be modified or replaced in the image sensor (1a) can be combined with each other to form a new modified example of an image sensor.

[0098] First, with reference to FIGS. 5 and FIGS. 6, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 5 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 6 is a schematic cross-sectional view showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIGS. 5 to explain an example of an image sensor according to another embodiment of the present invention.

[0099] Referring to FIGS. 5 and 6, the image sensor (1b) in the modified example may include an insulating structure (232a) that can replace the insulating structure (132a of FIG. 2) described in FIG. 2.

[0100] The insulating structure (232a) may include a lower layer (134), an intermediate layer (236a, 242a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layer (236a, 242a) may include a first intermediate layer (236a) and a second intermediate layer (242a) stacked in sequence. The first intermediate layer (236a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (242a) may include silicon oxide.

[0101] The insulating structure (232a) may include a first region (232A) and a second region (232B) having a thickness smaller than that of the first region (232A).

[0102] In the first region (232A) of the insulating structure (232a), the second intermediate layer (242a) may be formed by a first layer (244a) and a second layer (244b) stacked in sequence, and in the second region (232B) of the insulating structure (232a), the second intermediate layer (242a) may be formed by the second layer (244b). The first layer (244a) and the second layer (244b) of the second intermediate layer (242a) may each contain the same material, for example, silicon oxide.

[0103] The second intermediate layer (242a) may include a thick portion formed by the first and second layers (244a, 244b) and a thin portion formed by the second layer (244b). Depending on the thickness difference according to the position of the second intermediate layer (242a), a thickness difference may occur between the first and second regions (232A, 232B) of the insulating structure (232a).

[0104] The edge portions of each of the third color filters (170c), the first and second color filters (170a, 170b), and the grid structure (160) may be placed on the second region (232B) of the insulating structure (232a), and the center portions of each of the third color filters (170c) may be placed on the first region (232A) of the insulating structure (232a).

[0105] The region where the thickness changes in the insulating structure (232a), that is, the boundary region (232br) between the first region (232A) and the second region (232B), can be vertically superimposed with the third color filters (170c), spaced apart from the sides of the third color filters (170c), and spaced apart from the grid structure (160).

[0106] In the top view, the boundary area (232br) between the first area (232A) and the second area (232B) may be described as the boundary area between the center portion and the edge portion in each of the third color filters (170c).

[0107] In each of the third color filters (170c), the lower surface of the center portion may be positioned at a higher level than the lower surface of the edge portion. The lower surfaces of the first color filters (170a), the lower surfaces of the second color filters (170b), the lower surface of the edge portion of each of the third color filters (170c), and the lower surface of the grid structure (160) may be positioned at substantially the same level.

[0108] The image sensor (1b) may include an insulating structure (232a) in which the thickness of the first and second regions (232A, 232B) varies according to the thickness change of the second intermediate layer (242a) as described in FIGS. 5 and 6. Accordingly, the image sensor (1b) may include an insulating structure (232a) having an optimized thickness according to the wavelengths of the second and third color filters (170b, 170c), thereby improving the transmittance of light passing through the insulating structure (232a) through the second and third color filters (170b, 170c), namely the green color filter (170b) and the red color filter (170c), and thus improving the sensitivity of the image sensor (1b).

[0110] Next, with reference to FIG. 7, a modified example of the insulating structure (232a in FIG. 6) will be described. FIG. 7 is a schematic cross-sectional view showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIG. 5 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0111] Referring to FIGS. 5 and 7, an insulating structure (232b) such as FIG. 7, which can replace the insulating structure (232a) in FIG. 6, may include a lower layer (134), an intermediate layer (236b, 242b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2.

[0112] The above intermediate layers (236b, 242b) may include a first intermediate layer (236b) and a second intermediate layer (242b) stacked in sequence. The first intermediate layer (236b) may include a material substantially identical to the first intermediate layer (136a in FIG. 2), such as a high dielectric material like hafnium oxide, and the second intermediate layer (242b) may include silicon oxide.

[0113] The insulating structure (132b) may include the first region (232A) and the second region (232B) having a thickness smaller than that of the first region (232A), as described in FIG. 6.

[0114] In the first region (232A) of the insulating structure (232b), the first intermediate layer (236b) may be formed by a first layer (238a) and a second layer (238b) stacked in sequence, and in the second region (232B) of the insulating structure (232b), the first intermediate layer (236b) may be formed by the second layer (238b).

[0115] In one example, the first layer (238a) and the second layer (238b) of the first intermediate layer (236b) may each contain the same material, for example, hafnium oxide. In another example, the first layer (238a) and the second layer (238b) of the first intermediate layer (236b) may be formed of different materials.

[0116] The first intermediate layer (236b) may include a thick portion formed by the first and second layers (238a, 238b) and a thin portion formed by the second layer (238b). Depending on the thickness difference according to the position of the first intermediate layer (236b), a thickness difference may occur between the first and second regions (232A, 232B) of the insulating structure (232b), substantially the same as the insulating structure (232a) in FIG. 6.

[0118] Next, with reference to FIGS. 8a and FIGS. 8b, a modified example of the separation structure (115) of the image sensor (1b) of FIGS. 6 and FIGS. 7 will be described. FIGS. 8a and FIGS. 8b are schematic cross-sectional views showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIGS. 5 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0119] Referring to FIG. 8a, the separation structure (115) in FIG. 6 can be modified into a separation structure (115e) as in FIG. 8a. The separation structure (115) can be placed within the opening (112') as described in FIG. 4a. The insulating structure (232a in FIG. 6), which includes the first region (232A) and the second region (232B) having different thicknesses as in FIG. 6, can be modified into an insulating structure (232ca) that includes a portion extending into the opening (112').

[0120] In one example, the insulating structure (232ca) may include a lower layer (134'), an intermediate layer (236a', 242ca), and an upper layer (148) stacked in sequence. The intermediate layer (236a', 242ca) may include a first intermediate layer (236a') and a second intermediate layer (242ca) stacked in sequence. The second intermediate layer (242ca) may include a first layer (244a'), a second layer (244b'), and a third layer (344c').

[0121] The lower layer (134') may extend into the opening (112') to form the first layer (116a') of the separation structure (115e), and a part of the intermediate layer (136a', 142a), for example, the first intermediate layer (236a'), may extend into the opening (112') to form the second layer (116b') of the separation structure (115e), and the first layer (244a') of the second intermediate layer (242ca) may extend into the opening (112') to form the third layer (116c') of the separation structure (115').

[0122] In one example, the second layer (244b') and the third layer (244c') of the second intermediate layer (242ca) may correspond to the first layer (244a) and the second layer (244b) of the second intermediate layer (244a) described in FIG. 6, respectively, and may be formed of the same material as the first layer (244a) and the second layer (244b) of the second intermediate layer (244a) described in FIG. 6. In the second intermediate layer (242ca), the first layer (244a') may include the same material as the second layer (244b') and the third layer (244c'), for example, silicon oxide.

[0123] In another example, the first layer (244a') of the second intermediate layer (242ca) may be omitted, and the third layer (244c') of the second intermediate layer (242ca) may be extended into the opening (112') to form the third layer (116c') of the separation structure (115').

[0125] Next, referring to FIG. 1 and FIG. 8b, the separation structure (115 in FIG. 7) in FIG. 7 can be modified into a separation structure (115') as in FIG. 8b. The separation structure (1151) can be placed within the opening (112') as described in FIG. 4a.

[0126] The insulating structure (232b in FIG. 7) described in FIG. 7 may be modified into an insulating structure (232cb) comprising at least one layer of material extending into the opening (112'). For example, at least a portion of the insulating structure (232b in FIG. 7) described in FIG. 7 may extend into the opening (112') to form the separating structure (115'). For example, the separating structure (115') may include a first layer (116a'), a second layer (116b'), and a third layer (116c') that sequentially cover the inner wall of the opening (112'), and the first to third layers (116a', 116b', 116c') may be formed by extending from at least a portion of the insulating structure (232cb).

[0127] In one example, the insulating structure (232cb) may include a lower layer (134'), an intermediate layer (236b', 242b'), and an upper layer (148) stacked in sequence. The intermediate layer (236b', 242b') may include a first intermediate layer (236b') and a second intermediate layer (242b') stacked in sequence. The first intermediate layer (236b') may include a first layer (238a') and a second layer (238b') stacked in sequence.

[0128] The lower layer (134'), the intermediate layer (138b', 142b'), and the upper layer (148) of the insulating structure (132cb) described above may correspond to the lower layer (134), the intermediate layer (236b, 242b), and the upper layer (148) of the insulating structure (232b) described in FIG. 7, respectively, and may be formed of the same material as the lower layer (134), the intermediate layer (236b, 242b), and the upper layer (148) of the insulating structure (232b) described in FIG. 7.

[0129] The lower layer (134') may extend into the opening (112') to form the first layer (116a') of the separation structure (115'), and in the intermediate layer (236b', 242b'), the second layer (238b') of the first intermediate layer (236b') may extend into the opening (112') to form the second layer (116b') of the separation structure (115'), and the second intermediate layer (242b') may extend into the opening (112') to form the third layer (116c') of the separation structure (115').

[0131] In FIGS. 6, 7, 8a, and 8b, the second surface (106s2) of the second substrate (106) may be substantially flat, but embodiments of the present invention are not limited thereto. For example, in FIGS. 6, 7, 8a, and 8b, the second surface (106s2) of the second substrate (106) may be modified into a second surface having an uneven structure. Hereinafter, with reference to FIGS. 9c and 9d, examples of modification of the second surface (106s2) of the second substrate (106) in FIGS. 8a and 8b will be described. FIGS. 9c and 9d are schematic cross-sectional views showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIG. 5 to explain examples of modification of an image sensor according to another embodiment of the present invention.

[0132] Referring to FIGS. 5 and FIGS. 9a, in FIGS. 8a described above, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and FIGS. 4d. Likewise, in FIGS. 6, the second surface (106s2) of the second substrate (106) may be deformed into a second surface (106s2') having an uneven structure.

[0133] Referring to FIGS. 5 and FIGS. 9b, in FIGS. 8b described above, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and FIGS. 4d. Likewise, the second surface (106s2) of the second substrate (106) in FIGS. 8 may be deformed into a second surface (106s2') having an uneven structure.

[0135] Next, with reference to FIGS. 10 and FIGS. 11, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 10 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 11 is a schematic cross-sectional view showing regions taken along the lines Ic-Ic' and IIc-IIc' of FIGS. 10 to explain an example of an image sensor according to another embodiment of the present invention.

[0136] Referring to FIGS. 10 and 11, the image sensor (1c) in the modified example may include an insulating structure (332a) that can replace the insulating structure (132a of FIG. 2) described in FIG. 2.

[0137] The insulating structure (332a) may include a lower layer (134), an intermediate layer (336a, 342a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layer (336a, 342a) may include a first intermediate layer (336a) and a second intermediate layer (342a) stacked in sequence. The first intermediate layer (336a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (342a) may include silicon oxide.

[0138] The insulating structure (332a) may include a first region (332A), a second region (332B) having a thickness greater than that of the first region (332A), and a third region (332C) having a thickness greater than that of the second region (332B).

[0139] In the third region (332C) of the insulating structure (332a), the second intermediate layer (342a) may be formed by a first layer (344a), a second layer (344b), and a third layer (344c) stacked in sequence; in the second region (332B) of the insulating structure (332a), the second intermediate layer (342a) may be formed by the second layer (344b) and the third layer (344c) stacked in sequence; and in the first region (332A) of the insulating structure (332a), the second intermediate layer (342a) may be formed by the third layer (344c).

[0140] In one example, the first layer (344a), the second layer (344b), and the third layer (344c) of the second intermediate layer (342a) may each contain the same material, for example, silicon oxide. In another example, at least two of the first layer (344a), the second layer (344b), and the third layer (344c) of the second intermediate layer (342a) may be formed of different materials.

[0141] The second intermediate layer (342a) may include a maximum thickness portion formed by the first to third layers (344a, 344b, 344c), an intermediate thickness portion formed by the second and third layers (344b, 344c), and a minimum thickness portion formed by the third layer (344c). Depending on the thickness difference according to the position of the second intermediate layer (342a), a thickness difference may occur in the first to third regions (332A, 332B, 332C) of the insulating structure (332a).

[0142] The edge portions of each of the second color filters (170b), the third color filters (170c), the edge portions of each of the first color filters (170a), and the grid structure (160) may be placed on the second region (332B) of the insulating structure (332a), the center portions of each of the third color filters (170c) may be placed on the third region (332C) of the insulating structure (332a), and the center portions of each of the first color filters (170a) may be placed on the first region (332A) of the insulating structure (332a).

[0143] The region where the thickness changes in the insulating structure (332a), that is, the first boundary region (332br1) between the first region (332A) and the second region (332B), may overlap vertically with the first color filters (170a) and be spaced apart from the grid structure (160), and the second boundary region (332br2) between the second region (332B) and the third region (332C) may overlap vertically with the third color filters (170c) and be spaced apart from the grid structure (160).

[0144] In the top view, the first boundary area (332br1) between the first area (332A) and the second area (332B) may be described as the boundary area between the center and the edge portions in each of the first color filters (170a), and the second boundary area (332br2) between the second area (332B) and the third area (332C) may be described as the boundary area between the center and the edge portions in each of the third color filters (170c).

[0145] The image sensor (1c) may include an insulating structure (332a) in which the thickness of the first to third regions (332A, 332B, 323C) varies according to the thickness change of the second intermediate layer (342a) as described in FIGS. 10 and 11. Accordingly, the image sensor (1c) may include an insulating structure (332a) having an optimized thickness according to the wavelengths of the first, second, and third color filters (170a, 170b, 170c), so that the transmittance of light passing through the insulating structure (332a) through the first, second, and third color filters (170a, 170b, 170c), namely the blue color filter (170a), the green color filter (170b), and the red color filter (170c), can be improved, thereby improving the sensitivity of the image sensor (1c).

[0147] Next, with reference to FIG. 12, a modified example of the insulating structure (332a in FIG. 11) will be described. FIG. 12 is a schematic cross-sectional view showing regions taken along the lines Ic-Ic' and IIc-IIc' of FIG. 10 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0148] Referring to FIG. 10 and FIG. 12, an insulating structure (332b) such as FIG. 12, which can replace the insulating structure (332a) in FIG. 11, may include a lower layer (134), an intermediate layer (336b, 342b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2.

[0149] The above intermediate layers (336b, 342b) may include a first intermediate layer (336b) and a second intermediate layer (342b) stacked in sequence. The first intermediate layer (336b) may include a high dielectric material such as hafnium oxide, for example, which is substantially the same material as the first intermediate layer (136a in FIG. 2) in FIG. 2, and the second intermediate layer (342b) may include silicon oxide.

[0150] The insulating structure (332b) may include the first region (332A), the second region (332B) having a thickness greater than that of the first region (332A), and the third region (332C) having a thickness greater than that of the second region (332B), as described in FIG. 11.

[0151] In the third region (332C) of the insulating structure (332b), the first intermediate layer (336b) may be formed by a first layer (338a), a second layer (338b), and a third layer (338c) stacked in sequence; in the second region (332B) of the insulating structure (332b), the first intermediate layer (336b) may be formed by a second layer (338b) and a third layer (338c) stacked in sequence; and in the first region (332A) of the insulating structure (332b), the first intermediate layer (336b) may be formed by a third layer (338c).

[0152] In one example, the first layer (338a), the second layer (338b), and the third layer (338c) of the first intermediate layer (336b) may each contain the same material, for example, hafnium oxide. In another example, at least two of the first layer (338a), the second layer (338b), and the third layer (338c) of the first intermediate layer (336b) may be formed of different materials.

[0153] The first intermediate layer (336b) may include a maximum thickness portion formed by the first to third layers (338a, 338b, 338c), an intermediate thickness portion formed by the second and third layers (338b, 338c), and a minimum thickness portion formed by the third layer (338c). Depending on the thickness difference according to the position of the first intermediate layer (336b), a thickness difference may occur in the first to third regions (332A, 332B, 332C) of the insulating structure (332b).

[0154] The edge portions of each of the second color filters (170b), the third color filters (170c), the edge portions of each of the first color filters (170a), and the grid structure (160) may be placed on the second region (332B) of the insulating structure (332b), the center portions of each of the third color filters (170c) may be placed on the third region (332C) of the insulating structure (332b), and the center portions of each of the first color filters (170a) may be placed on the first region (332A) of the insulating structure (332b).

[0156] Next, with reference to FIG. 13, a modified example of the separation structure (115) of the image sensor (1c) of FIG. 11 and FIG. 12 will be described. FIG. 13 is a schematic cross-sectional view showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIG. 10 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0157] Referring to FIG. 13, the separation structure (115) in FIG. 11 and FIG. 12 can be modified into a separation structure (115') disposed within the opening (112') as described in FIG. 4a. The separation structure (115') may include at least two layers, for example, a first layer (115a') and a second layer (115b') on the first layer (115a'). The insulating structure (332a in FIG. 11 or 332b in FIG. 12), comprising the first region (332A), the second region (332B), and the third region (332C) having different thicknesses as in FIG. 11 and 12, can be transformed into an insulating structure (332c) comprising a portion extending into the opening (112') that extends in a direction from the second surface (106s2) of the second substrate (106) as in FIG. 4a toward the first surface (106s1).

[0158] In one example, the insulating structure (332c) may include a lower layer (134'), an intermediate layer (336a', 342a), and an upper layer (148) stacked in sequence. The intermediate layer (336a', 342a) may include a first intermediate layer (336a') and a second intermediate layer (342a) stacked in sequence.

[0159] The lower layer (134') may extend into the opening (112') to form the first layer (115a') of the separation structure (115'), and a part of the intermediate layer (336a', 342a), for example, the first intermediate layer (336a'), may extend into the opening (112') to form the second layer (115b') of the separation structure (115').

[0161] Next, with reference to FIG. 14, a modified example of the second surface (106s2) of the second substrate (106) in FIG. 11, FIG. 12, and FIG. 13 will be described. FIG. 14 is a schematic cross-sectional view showing regions taken along the lines Ib-Ib' and IIb-IIb' of FIG. 10 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0162] Referring to FIGS. 10 and 14, in FIGS. 11, 12 and 13 described above, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and 4d.

[0164] Next, with reference to FIGS. 15 and FIGS. 16, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 15 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 16 is a schematic cross-sectional view showing regions taken along the Id-Id' and IId-IId' lines of FIGS. 15 to explain an example of an image sensor according to another embodiment of the present invention.

[0165] Referring to FIGS. 15 and 16, the image sensor (1d) in the modified example may include an insulating structure (432a) that can replace the insulating structure (132a in FIG. 2) described in FIG. 2.

[0166] The insulating structure (432a) may include a lower layer (134), intermediate layers (436a, 442a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (436a, 442a) may include a first intermediate layer (436a) and a second intermediate layer (442a) stacked in sequence. The first intermediate layer (436a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (442a) may include silicon oxide.

[0167] The insulating structure (432a) may include a first region (432A), a second region (432B) having a thickness greater than that of the first region (432A), and a third region (432C) having a thickness greater than that of the second region (432B).

[0168] In the third region (432C) of the insulating structure (432a), the second intermediate layer (442a) may be formed by a first layer (444a), a second layer (444b), and a third layer (444c) stacked in sequence; in the second region (432B) of the insulating structure (432a), the second intermediate layer (442a) may be formed by the second layer (444b) and the third layer (444c) stacked in sequence; and in the first region (432A) of the insulating structure (432a), the second intermediate layer (442a) may be formed by the third layer (444c).

[0169] In one example, the first layer (444a), the second layer (444b), and the third layer (444c) of the second intermediate layer (442a) may each contain the same material, for example, silicon oxide. In another example, at least two of the first layer (444a), the second layer (444b), and the third layer (444c) of the second intermediate layer (442a) may be formed of different materials.

[0170] The second intermediate layer (442a) may include a maximum thickness portion formed by the first to third layers (444a, 444b, 444c), an intermediate thickness portion formed by the second and third layers (444b, 444c), and a minimum thickness portion formed by the third layer (444c). Depending on the thickness difference according to the position of the second intermediate layer (442a), a thickness difference may occur in the first to third regions (432A, 432B, 432C) of the insulating structure (432a).

[0171] The third color filters (170c), the edge portions of each of the second color filters (170b), the edge portions of each of the first color filters (170a), and the grid structure (160) may be placed on the third region (432C) of the insulating structure (432a), the center portions of each of the second color filters (170b) may be placed on the second region (432B) of the insulating structure (432a), and the center portions of each of the first color filters (170a) may be placed on the first region (432A) of the insulating structure (432a).

[0172] The region where the thickness changes in the insulating structure (432a), that is, the first boundary region (432br1) between the first region (432A) and the second region (432B), may overlap vertically with the first color filters (170a) and be spaced apart from the grid structure (160), and the second boundary region (432br2) between the second region (432B) and the third region (432C) may overlap vertically with the second color filters (170b) and be spaced apart from the grid structure (160).

[0173] In the top view, the first boundary area (432br1) between the first area (432A) and the second area (432B) may be described as the boundary area between the center and the edge portions in each of the first color filters (170a), and the second boundary area (432br2) between the second area (432B) and the third area (432C) may be described as the boundary area between the center and the edge portions in each of the second color filters (170b).

[0174] In each of the first color filters (170a), the lower surface of the center portion may be positioned at a lower level than the lower surface of the edge portion, and in each of the second color filters (170b), the lower surface of the center portion may be positioned at a lower level than the lower surface of the edge portion. The lower surface of the center portion of each of the second color filters (170b) may be positioned at a higher level than the lower surface of the center portion of each of the first color filters (170a). The lower surface of the edge portion of each of the first color filters (170a), the lower surface of the edge portion of each of the second color filters (170b), the lower surfaces of the third color filters (170c), and the lower surface of the grid structure (160) may be positioned at substantially the same level.

[0175] The image sensor (1d) may include an insulating structure (432a) in which the thickness of the first to third regions (432A, 432B, 423C) varies according to the thickness change of the second intermediate layer (442a) as described in FIGS. 15 and 16. Accordingly, the image sensor (1d) may include an insulating structure (432a) having an optimized thickness according to the wavelengths of the first, second, and third color filters (170a, 170b, 170c), so that the transmittance of light passing through the insulating structure (432a) through the first, second, and third color filters (170a, 170b, 170c), namely the blue color filter (170a), the green color filter (170b), and the red color filter (170c), can be improved, thereby improving the sensitivity of the image sensor (1d).

[0177] Next, with reference to FIG. 17, a modified example of the insulating structure (432a in FIG. 16) will be described. FIG. 17 is a schematic cross-sectional view showing regions taken along the Id-Id' and IId-IId' lines of FIG. 15 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0178] Referring to FIGS. 15 and 17, an insulating structure (432b) such as FIG. 17, which can replace the insulating structure (432a) in FIG. 16, may comprise a lower layer (134), an intermediate layer (436b, 442b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2.

[0179] The above intermediate layers (436b, 442b) may include a first intermediate layer (436b) and a second intermediate layer (442b) stacked in sequence. The first intermediate layer (436b) may include a material substantially identical to the first intermediate layer (136a in FIG. 2), such as a high dielectric material like hafnium oxide, and the second intermediate layer (442b) may include silicon oxide.

[0180] The insulating structure (432b) may include the first region (432A), the second region (432B) having a thickness greater than that of the first region (432A), and the third region (432C) having a thickness greater than that of the second region (432B), as described in FIG. 16.

[0181] In the third region (432C) of the insulating structure (432b), the first intermediate layer (436b) may be formed by a first layer (438a), a second layer (438b), and a third layer (438c) stacked in sequence; in the second region (432B) of the insulating structure (432b), the first intermediate layer (436b) may be formed by a second layer (438b) and a third layer (438c) stacked in sequence; and in the first region (432A) of the insulating structure (432b), the first intermediate layer (436b) may be formed by a third layer (438c).

[0182] In one example, the first layer (438a), the second layer (438b), and the third layer (438c) of the first intermediate layer (436b) may each contain the same material, for example, hafnium oxide. In another example, at least two of the first layer (438a), the second layer (438b), and the third layer (438c) of the first intermediate layer (436b) may be formed of different materials.

[0183] The first intermediate layer (436b) may include a maximum thickness portion formed by the first to third layers (438a, 438b, 438c), an intermediate thickness portion formed by the second and third layers (438b, 438c), and a minimum thickness portion formed by the third layer (438c). Depending on the thickness difference according to the position of the first intermediate layer (436b), a thickness difference may occur in the first to third regions (432A, 432B, 432C) of the insulating structure (432b), as described in FIG. 16.

[0185] Next, with reference to FIG. 18a, a modified example of the separation structure (115) of the image sensor (1d) of FIG. 16 and FIG. 17 will be described. FIG. 18a is a schematic cross-sectional view showing regions taken along the Id-Id' and IId-IId' lines of FIG. 15 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0186] Referring to FIG. 18a, the separation structure (115) in FIG. 16 and FIG. 17 can be modified into a separation structure (115') disposed within the opening (112') as described in FIG. 4a. The separation structure (115') may include at least two layers, for example, a first layer (115a') and a second layer (115b') on the first layer (115a'). The insulating structure (432a in FIG. 16 or 432b in FIG. 17), which includes the first region (432A), the second region (432B), and the third region (432C) having different thicknesses as in FIG. 16 and FIG. 17, can be modified into an insulating structure (432c) that includes a portion extending into the opening (112').

[0187] In one example, the insulating structure (432c) may include a lower layer (134'), an intermediate layer (436a', 442a), and an upper layer (148) stacked in sequence. The intermediate layer (436a', 442a) may include a first intermediate layer (436a') and a second intermediate layer (442a) stacked in sequence. The lower layer (134') may extend into the opening (112') to form a first layer (115a') of the separation structure (115'), and a part of the intermediate layer (436a', 442a), for example, the first intermediate layer (436a'), may extend into the opening (112') to form a second layer (115b') of the separation structure (115').

[0189] Next, with reference to FIG. 18b, a modified example of the second surface (106s2) of the second substrate (106) in FIG. 16, FIG. 17, and FIG. 18a will be described. FIG. 18b is a schematic cross-sectional view showing regions taken along the Id-Id' and IId-IId' lines of FIG. 15 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0190] Referring to FIGS. 15 and FIGS. 18b, the second surface (106s2) of the second substrate (106) described above in FIGS. 16, 17 and 18a may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and 4d.

[0192] Next, with reference to FIGS. 19 and FIGS. 20, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 19 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 20 is a schematic cross-sectional view showing regions taken along the lines Ie-Ie' and IIe-IIe' of FIGS. 19 to explain an example of an image sensor according to another embodiment of the present invention.

[0193] Referring to FIGS. 19 and 20, the image sensor (1e) in the modified example may include an insulating structure (532a) that can replace the insulating structure (132a in FIG. 2) described in FIG. 2, color filters (570) that can replace the color filters (170) described in FIG. 2, and a grid structure (560) that can replace the grid structure (160) described in FIG. 2.

[0194] The insulating structure (532a) may include a lower layer (134), an intermediate layer (536a, 542a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layer (536a, 542a) may include a first intermediate layer (536a) and a second intermediate layer (542a) stacked in sequence. The first intermediate layer (536a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (542a) may include silicon oxide.

[0195] The insulating structure (532a) may include a first region (532A) and a second region (532B) having a thickness greater than that of the first region (532A).

[0196] In the second region (532B) of the insulating structure (532a), the second intermediate layer (542a) may be formed by a first layer (544a) and a second layer (544b) stacked in sequence, and in the first region (532A) of the insulating structure (532a), the second intermediate layer (542a) may be formed by the second layer (544b).

[0197] In one example, the first layer (544a) and the second layer (544b) of the second intermediate layer (542a) may comprise the same material, for example, silicon oxide. In another example, the first layer (544a) and the second layer (544b) of the second intermediate layer (542a) may be formed of different materials.

[0198] The second intermediate layer (542a) may include a maximum thickness portion formed by the first and second layers (544a, 544b) and a minimum thickness portion formed by the second layer (544b). Depending on the thickness difference according to the position of the second intermediate layer (542a), a thickness difference may occur between the first and second regions (532A, 532B) of the insulating structure (532a).

[0199] The above color filters (770) may include first color filters (570a), second color filters (570b), and third color filters (570c). For example, the first color filters (570a) may be blue color filters, the second color filters (570b) may be green color filters, and the third color filters (570c) may be red color filters.

[0200] Each of the above color filters (570) can be vertically superimposed with a plurality of the above photoelectric conversion elements, for example, photodiodes (PDs). For example, any one of the above color filters (770), for example, one first color filter (570a), can be vertically superimposed with a plurality of the above photoelectric conversion elements (PDs). Any one of the above color filters (770), for example, one first color filter (570a), can be vertically superimposed with a part of the separation structure (115).

[0201] The grid structure (560) may be placed between color filters of different colors among the color filters (570). The grid structure (560) may include a first layer (162a) and a second layer (162b) stacked in sequence as described in FIG. 2.

[0202] The edge portions of each of the third color filters (570c), the second color filters (570b), and the first color filters (570a), and the grid structure (560) may be placed on the second region (532B) of the insulating structure (532a), and the center portions of each of the first color filters (570a) may be placed on the first region (532A) of the insulating structure (532a).

[0203] The region where the thickness changes in the insulating structure (532a), that is, the boundary region (532br) between the first region (532A) and the second region (532B), may overlap perpendicularly with the first color filters (570a) and be spaced apart from the grid structure (560).

[0204] In the top view, the boundary area (532br) between the first area (532A) and the second area (532B) may be described as the boundary area between the center portion and the edge portion in each of the first color filters (570a).

[0205] The image sensor (1e) may include an insulating structure (532a) in which the thickness of the first and second regions (532A, 532B) varies according to the thickness change of the second intermediate layer (542a). Accordingly, the image sensor (1e) may include an insulating structure (532a) having an optimized thickness according to the wavelengths of the first and second color filters (570a, 570b), so that the transmittance of light passing through the insulating structure (532a) through the first and second color filters (570a, 570b), namely the blue color filter (570a) and the green color filter (570b), can be improved, thereby improving the sensitivity of the image sensor (1e).

[0207] Next, with reference to FIG. 21, a modified example of the insulating structure (532a) will be described. FIG. 21 is a schematic cross-sectional view showing regions taken along the Ie-Ie' and IIe-IIe' lines of FIG. 19 to explain a modified example of an image sensor according to an embodiment of the present invention.

[0208] Referring to FIG. 19 and FIG. 21, an insulating structure (532b) such as FIG. 21, which can replace the insulating structure (532a) in FIG. 20, may comprise a lower layer (134), intermediate layers (536b, 542b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (536b, 542b) may comprise a first intermediate layer (536b) and a second intermediate layer (542b) stacked in sequence. The first intermediate layer (536b) may comprise a high dielectric material such as hafnium oxide, for example, the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (542b) may comprise silicon oxide.

[0209] The insulating structure (532b) may include a first region (532A) having a first thickness and a second region (532B) having a second thickness greater than the first thickness, as described in FIG. 20.

[0210] In the second region (532B) of the insulating structure (532b), the first intermediate layer (536b) may be formed by a first layer (538a) and a second layer (538b) stacked in sequence, and in the first region (532A) of the insulating structure (532b), the first intermediate layer (536b) may be formed by the second layer (538b).

[0211] In one example, the first layer (538a) and the second layer (538b) of the first intermediate layer (536b) may each contain the same material, for example, hafnium oxide. In another example, the first layer (538a) and the second layer (538b) of the first intermediate layer (536b) may be formed of different materials.

[0212] The first intermediate layer (536b) may include a thick portion formed by the first and second layers (538a, 538b) and a thin portion formed by the second layer (538b). Depending on the thickness difference according to the position of the first intermediate layer (536b), a thickness difference may occur between the first and second regions (532A, 532B) of the insulating structure (532b) as described in FIG. 20.

[0214] Next, with reference to FIG. 22, a modified example of the separation structure (115) of the image sensor (1e) of FIG. 20 and FIG. 21 will be described. FIG. 22 is a schematic cross-sectional view showing regions taken along the lines Ie-Ie' and IIe-IIe' of FIG. 20 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0215] Referring to FIG. 22, the separation structure (115) in FIG. 20 and FIG. 21 can be modified into a separation structure (115') disposed within the opening (112') as described in FIG. 4a. The separation structure (115') may include at least two layers, for example, a first layer (115a') and a second layer (115b') on the first layer (115a'). The insulating structure (532a in FIG. 20 or 532b in FIG. 21), which includes the first region (532A) and the second region (532B) having different thicknesses as in FIG. 20 and FIG. 21, can be modified into an insulating structure (532c) that includes a portion extending into the opening (112').

[0216] In one example, the insulating structure (532c) may include a lower layer (134'), an intermediate layer (536a', 542a), and an upper layer (148) stacked in sequence. The intermediate layer (536a', 542a) may include a first intermediate layer (536a') and a second intermediate layer (542a) stacked in sequence. The lower layer (134') may extend into the opening (112') to form a first layer (115a') of the separation structure (115'), and a part of the intermediate layer (536a', 542a), for example, the first intermediate layer (536a'), may extend into the opening (112') to form a second layer (115b') of the separation structure (115').

[0218] Next, with reference to FIG. 23, a modified example of the second surface (106s2) of the second substrate (106) in FIG. 20, FIG. 21, and FIG. 22 will be described. FIG. 23 is a schematic cross-sectional view showing regions taken along the Ie-Ie' and IIe-IIe' lines of FIG. 19 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0219] Referring to FIGS. 20 and 23, in FIGS. 20, 21 and 22 described above, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and 4d.

[0221] Next, with reference to FIGS. 24 and FIGS. 25, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 24 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 25 is a schematic cross-sectional view showing regions taken along the If-If' line and the IIf-IIf' line of FIGS. 24 to explain an example of an image sensor according to another embodiment of the present invention.

[0222] Referring to FIGS. 24 and 25, the image sensor (1f) in the modified example may include an insulating structure (632a) that can replace the insulating structure (532a in FIG. 20) in the image sensor (1e) of FIG. 20. Accordingly, the image sensor (1f) may include the same color filters (570) and grid structure (560) as the image sensor (1e) of FIG. 20.

[0223] The insulating structure (632a) may include a lower layer (134), an intermediate layer (636a, 642a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layer (636a, 642a) may include a first intermediate layer (636a) and a second intermediate layer (642a) stacked in sequence. The first intermediate layer (636a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (642a) may include silicon oxide.

[0224] The insulating structure (632a) may include a first region (632A) and a second region (632B) having a thickness smaller than that of the first region (632A).

[0225] In the first region (632A) of the insulating structure (632a), the second intermediate layer (642a) may be formed by a first layer (644a) and a second layer (644b) stacked in sequence, and in the second region (632B) of the insulating structure (632a), the second intermediate layer (642a) may be formed by the second layer (644b).

[0226] In one example, the first layer (644a) and the second layer (644b) of the second intermediate layer (642a) may comprise the same material, for example, silicon oxide. In another example, the first layer (644a) and the second layer (644b) of the second intermediate layer (642a) may be formed of different materials.

[0227] The second intermediate layer (642a) may include a maximum thickness portion formed by the first and second layers (644a, 644b) and a minimum thickness portion formed by the second layer (644b). Depending on the thickness difference according to the position of the second intermediate layer (642a), a thickness difference may occur between the first and second regions (632A, 632B) of the insulating structure (632a).

[0228] The region where the thickness changes in the insulating structure (632a), that is, the boundary region (632br) between the first region (632A) and the second region (632B), may overlap perpendicularly with the third color filters (570c) and be spaced apart from the grid structure (560).

[0229] In the top view, the boundary area (632br) between the first area (632A) and the second area (632B) may be described as the boundary area between the center portion and the edge portion in each of the third color filters (570c).

[0230] The image sensor (1f) may include an insulating structure (632a) in which the thickness of the first and second regions (632A, 632B) varies according to the thickness change of the second intermediate layer (642a). Accordingly, since the image sensor (1f) may include an insulating structure (632a) having an optimized thickness according to the wavelengths of the second and third color filters (570b, 570c), the transmittance of light passing through the insulating structure (632a) through the second and third color filters (570b, 570c), namely the green color filter (570b) and the red color filter (570c), can be improved, thereby improving the sensitivity of the image sensor (1f).

[0232] Next, with reference to FIG. 26, a modified example of the insulating structure (632a) will be described. FIG. 26 is a schematic cross-sectional view showing regions taken along the If-If' and IIf-IIf' lines of FIG. 24 to explain a modified example of an image sensor according to an embodiment of the present invention.

[0233] Referring to FIGS. 24 and 26, an insulating structure (632b) such as FIG. 26, which can replace the insulating structure (632a) in FIG. 25, may comprise a lower layer (134), intermediate layers (636b, 642b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (636b, 642b) may comprise a first intermediate layer (636b) and a second intermediate layer (642b) stacked in sequence. The first intermediate layer (636b) may comprise a high dielectric material such as hafnium oxide, for example, the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (642b) may comprise silicon oxide.

[0234] The insulating structure (632b) may include a first region (632A) having a first thickness and a second region (632B) having a second thickness greater than the first thickness, as described in FIG. 25.

[0235] In the first region (632A) of the insulating structure (632b), the first intermediate layer (636b) may be formed by a first layer (638a) and a second layer (638b) stacked in sequence, and in the second region (632B) of the insulating structure (632b), the first intermediate layer (636b) may be formed by the second layer (638b).

[0236] In one example, the first layer (638a) and the second layer (638b) of the first intermediate layer (636b) may each contain the same material, for example, hafnium oxide. In another example, the first layer (638a) and the second layer (638b) of the first intermediate layer (636b) may be formed of different materials.

[0237] The first intermediate layer (636b) may include a thick portion formed by the first and second layers (638a, 638b) and a thin portion formed by the second layer (638b). Depending on the thickness difference according to the position of the first intermediate layer (636b), a thickness difference may occur between the first and second regions (632A, 632B) of the insulating structure (632b) as described in FIG. 25.

[0239] Next, with reference to FIG. 27, a modified example of the separation structure (115) of the image sensor (1f) of FIG. 25 and FIG. 26 will be described. FIG. 27 is a schematic cross-sectional view showing regions taken along the If-If' and IIf-IIf' lines of FIG. 24 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0240] Referring to FIG. 27, the separation structure (115) in FIG. 25 and FIG. 26 can be modified into a separation structure (115') disposed within the opening (112') as described in FIG. 4a. The separation structure (115') may include at least two layers, for example, a first layer (115a') and a second layer (115b') on the first layer (115a'). The insulating structure (632a in FIG. 25 or 632b in FIG. 26), which includes the first region (632A) and the second region (632B) having different thicknesses as in FIG. 25 and FIG. 26, can be modified into an insulating structure (632c) that includes a portion extending into the opening (112').

[0241] In one example, the insulating structure (632c) may include a lower layer (134'), an intermediate layer (636a', 642a), and an upper layer (148) stacked in sequence. The intermediate layer (636a', 642a) may include a first intermediate layer (636a') and a second intermediate layer (642a) stacked in sequence. The lower layer (134') may extend into the opening (112') to form a first layer (115a') of the separation structure (115'), and a part of the intermediate layer (636a', 642a), for example, the first intermediate layer (636a'), may extend into the opening (112') to form a second layer (115b') of the separation structure (115').

[0243] Next, with reference to FIG. 28, a modified example of the second surface (106s2) of the second substrate (106) in FIG. 25, FIG. 26, and FIG. 27 will be described. FIG. 28 is a schematic cross-sectional view showing regions taken along the If-If' line and IIf-IIf' line of FIG. 24 to explain a modified example of an image sensor according to another embodiment of the present invention.

[0244] Referring to FIGS. 24 and 28, in FIGS. 25, 26 and 27 described above, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be deformed into a second surface (106s2') having an uneven structure as described in FIGS. 4c and 4d.

[0246] Next, with reference to FIGS. 29 and FIGS. 30, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 29 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 30 is a schematic cross-sectional view showing regions taken along the Ifa-Ifa' and IIfa-IIfa' lines of FIGS. 29 to explain an example of an image sensor according to another embodiment of the present invention.

[0247] Referring to FIGS. 24 and 25, the image sensor (1fa) in the modified example may include an insulating structure (732a) that can replace the insulating structure (532a in FIG. 20) in the image sensor (1e) of FIG. 20. Accordingly, the image sensor (1fa) may include the same color filters (570) and grid structure (560) as the image sensor (1e) of FIG. 20.

[0248] The insulating structure (732a) may include a lower layer (134), intermediate layers (736a, 742a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (736a, 742a) may include a first intermediate layer (736a) and a second intermediate layer (742a) stacked in sequence. The first intermediate layer (736a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (742a) may include silicon oxide.

[0249] The insulating structure (732a) may include a first region (732A), a second region (732B) having a thickness greater than that of the first region (732A), and a third region (732C) having a thickness greater than that of the second region (732B).

[0250] In the third region (732C) of the insulating structure (732a), the second intermediate layer (742a) may be formed by a first layer (744a), a second layer (744b), and a third layer (744c) stacked in sequence; in the second region (732B) of the insulating structure (732a), the second intermediate layer (742a) may be formed by the second layer (744b) and the third layer (744c) stacked in sequence; and in the first region (732A) of the insulating structure (732a), the second intermediate layer (742a) may be formed by the third layer (744c).

[0251] In one example, the first layer (744a), the second layer (744b), and the third layer (744c) of the second intermediate layer (742a) may each contain the same material, for example, silicon oxide. In another example, at least two of the first layer (744a), the second layer (744b), and the third layer (744c) of the second intermediate layer (742a) may be formed of different materials.

[0252] The second intermediate layer (742a) may include a maximum thickness portion formed by the first to third layers (744a, 744b, 744c), an intermediate thickness portion formed by the second and third layers (744b, 744c), and a minimum thickness portion formed by the third layer (744c). Depending on the thickness difference according to the position of the second intermediate layer (742a), a thickness difference may occur in the first to third regions (732A, 732B, 732C) of the insulating structure (732a).

[0253] The edge portions of each of the second color filters (570b), the third color filters (570c), the edge portions of each of the first color filters (570a), and the grid structure (560) may be placed on the second region (732B) of the insulating structure (732a), the center portions of each of the third color filters (570c) may be placed on the third region (732C) of the insulating structure (732a), and the center portions of each of the first color filters (570a) may be placed on the first region (732A) of the insulating structure (732a).

[0254] The region where the thickness changes in the insulating structure (732a), that is, the first boundary region (732br1) between the first region (732A) and the second region (732B), may overlap vertically with the first color filters (570a) and be spaced apart from the grid structure (560), and the second boundary region (732br2) between the second region (732B) and the third region (732C) may overlap vertically with the third color filters (570c) and be spaced apart from the grid structure (560).

[0255] In the top view, the first boundary area (732br1) between the first area (732A) and the second area (732B) may be described as the boundary area between the center and the edge portions in each of the first color filters (570a), and the second boundary area (732br2) between the second area (732B) and the third area (732C) may be described as the boundary area between the center and the edge portions in each of the third color filters (570c).

[0256] The image sensor (1fa) may include an insulating structure (732a) in which the thickness of the first to third regions (732A, 732B, 323C) varies according to the thickness change of the second intermediate layer (742a). Accordingly, since the image sensor (1fa) may include an insulating structure (732a) having an optimized thickness according to the wavelengths of the first, second, and third color filters (570a, 570b, 570c), the transmittance of light passing through the insulating structure (732a) through the first, second, and third color filters (570a, 570b, 570c), namely the blue color filter (570a), the green color filter (570b), and the red color filter (570c), can be improved, thereby improving the sensitivity of the image sensor (1fa).

[0258] Next, with reference to FIG. 31, a modified example of the insulating structure (732a) will be described. FIG. 31 is a schematic cross-sectional view showing regions taken along the Ifa-Ifa' and IIfa-IIfa' lines of FIG. 29 to explain a modified example of an image sensor according to an embodiment of the present invention.

[0259] Referring to FIG. 29 and FIG. 31, an insulating structure (732b) such as FIG. 31, which can replace the insulating structure (732a) in FIG. 20, may comprise a lower layer (134), intermediate layers (736b, 742b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (736b, 742b) may comprise a first intermediate layer (736b) and a second intermediate layer (742b) stacked in sequence. The first intermediate layer (736b) may comprise a high dielectric material such as hafnium oxide, for example, the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (742b) may comprise silicon oxide.

[0260] The insulating structure (732b) may include, as described in FIG. 30, a first region (732A), a second region (732B) having a thickness greater than that of the first region (732A), and a third region (732C) having a thickness greater than that of the second region (732B).

[0261] In the third region (732C) of the insulating structure (732b), the first intermediate layer (736b) may be formed by a first layer (738a), a second layer (738b), and a third layer (738c) stacked in sequence; in the second region (732B) of the insulating structure (732b), the first intermediate layer (736b) may be formed by a second layer (738b) and a third layer (738c) stacked in sequence; and in the first region (732A) of the insulating structure (732b), the first intermediate layer (736b) may be formed by a third layer (738c).

[0262] In one example, the first layer (738a), the second layer (738b), and the third layer (738c) of the first intermediate layer (736b) may each contain the same material, for example, hafnium oxide. In another example, at least two of the first layer (738a), the second layer (738b), and the third layer (738c) of the first intermediate layer (736b) may be formed of different materials.

[0263] The first intermediate layer (736b) may include a maximum thickness portion formed by the first to third layers (738a, 738b, 738c), an intermediate thickness portion formed by the second and third layers (738b, 738c), and a minimum thickness portion formed by the third layer (738c). Depending on the thickness difference according to the position of the first intermediate layer (736b), a thickness difference may occur in the first to third regions (732A, 732B, 732C) of the insulating structure (732b), as shown in FIG. 30.

[0264] In another embodiment, the separation structure (115) in FIG. 30 and FIG. 31 may be modified into a separation structure (115') comprising a first layer (115a') and a second layer (115b') as in FIG. 4a, and the insulating structure (732a in FIG. 30 or 732b in FIG. 31) comprising the first region (732A), the second region (732B) and the third region (732C) having different thicknesses as in FIG. 30 and FIG. 31 may be modified into an insulating structure comprising a portion extending into the opening (112' in FIG. 4a) extending in a direction toward the first surface (106s1) from the second surface (106s2) of the second substrate (106) as in FIG. 4a.

[0265] In another embodiment, in FIG. 30 and FIG. 31, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be modified into a second surface (106s2') having an uneven structure as described in FIG. 4b.

[0267] Next, with reference to FIGS. 32 and FIGS. 33, an example of an image sensor according to another embodiment of the present invention will be described. FIGS. 32 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIGS. 33 is a schematic cross-sectional view showing regions taken along the Ig-Ig' line and IIg-IIg' line of FIGS. 32 to explain an example of an image sensor according to another embodiment of the present invention.

[0268] Referring to FIGS. 32 and 33, the image sensor (1g) in the modified example may include an insulating structure (832a) that can replace the insulating structure (532a in FIG. 20) in the image sensor (1e) of FIG. 20.

[0269] The insulating structure (832a) may include a lower layer (134), an intermediate layer (836a, 842a), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layer (836a, 842a) may include a first intermediate layer (836a) and a second intermediate layer (842a) stacked in sequence. The first intermediate layer (836a) may include a high dielectric material, such as hafnium oxide, which is substantially the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (842a) may include silicon oxide.

[0270] The insulating structure (832a) may include a first region (832A), a second region (832B) having a thickness greater than that of the first region (832A), and a third region (832C) having a thickness greater than that of the second region (832B).

[0271] In the third region (832C) of the insulating structure (832a), the second intermediate layer (842a) may be formed by a first layer (844a), a second layer (844b), and a third layer (844c) stacked in sequence; in the second region (832B) of the insulating structure (832a), the second intermediate layer (842a) may be formed by the second layer (844b) and the third layer (844c) stacked in sequence; and in the first region (832A) of the insulating structure (832a), the second intermediate layer (842a) may be formed by the third layer (844c).

[0272] In one example, the first layer (844a), the second layer (844b), and the third layer (844c) of the second intermediate layer (842a) may each contain the same material, for example, silicon oxide. In another example, at least two of the first layer (844a), the second layer (844b), and the third layer (844c) of the second intermediate layer (842a) may be formed of different materials.

[0273] The second intermediate layer (842a) may include a maximum thickness portion formed by the first to third layers (844a, 844b, 844c), an intermediate thickness portion formed by the second and third layers (844b, 844c), and a minimum thickness portion formed by the third layer (844c). Depending on the thickness difference according to the position of the second intermediate layer (842a), a thickness difference may occur in the first to third regions (832A, 832B, 832C) of the insulating structure (832a).

[0274] The center portion of each of the first color filters (570a) may be placed on the first region (832A) of the insulating structure (832a), the center portion of each of the second color filters (570b) may be placed on the second region (832B) of the insulating structure (832a), and the third color filters (570c), the edge portion of each of the first color filters (570a), the edge portion of each of the second color filters (570b), and the grid structure (560) may be placed on the second region (832B) of the insulating structure (832a).

[0275] The region where the thickness changes in the insulating structure (832a), that is, the first boundary region (832br1) between the first region (832A) and the second region (832B), may overlap vertically with the first color filters (570a) and be spaced apart from the grid structure (560), and the second boundary region (832br2) between the second region (832B) and the third region (832C) may overlap vertically with the second color filters (570c) and be spaced apart from the grid structure (560).

[0276] In the top view, the first boundary area (832br1) between the first area (832A) and the second area (832B) may be described as the boundary area between the center and the edge portions in each of the first color filters (570a), and the second boundary area (832br2) between the second area (832B) and the third area (832C) may be described as the boundary area between the center and the edge portions in each of the second color filters (570b).

[0277] The image sensor (1g) may include an insulating structure (832a) in which the thickness of the first to third regions (832A, 832B, 833C) varies according to the thickness change of the second intermediate layer (842a). Accordingly, since the image sensor (1g) may include an insulating structure (832a) having an optimized thickness according to the wavelengths of the first, second, and third color filters (570a, 570b, 570c), the transmittance of light passing through the insulating structure (832a) through the first, second, and third color filters (570a, 570b, 570c), namely the blue color filter (570a), the green color filter (570b), and the red color filter (570c), can be improved, thereby improving the sensitivity of the image sensor (1g).

[0279] Next, with reference to FIG. 34, a modified example of the insulating structure (832a) will be described. FIG. 34 is a schematic cross-sectional view showing regions taken along the Ig-Ig' and IIg-IIg' lines of FIG. 32 to explain a modified example of an image sensor according to one embodiment of the present invention.

[0280] Referring to FIGS. 32 and FIGS. 34, an insulating structure (832b) such as FIG. 34, which can replace the insulating structure (732a) in FIG. 20, may comprise a lower layer (134), intermediate layers (836b, 842b), and an upper layer (148) stacked in sequence. The lower layer (134) and the upper layer (148) may be substantially the same as those described in FIG. 2. The intermediate layers (836b, 842b) may comprise a first intermediate layer (836b) and a second intermediate layer (842b) stacked in sequence. The first intermediate layer (836b) may comprise a high dielectric material such as hafnium oxide, for example, the same material as the first intermediate layer (136a in FIG. 2), and the second intermediate layer (842b) may comprise silicon oxide.

[0281] The insulating structure (832b) may include, as described in FIG. 33, a first region (832A), a second region (832B) having a thickness greater than that of the first region (832A), and a third region (832C) having a thickness greater than that of the second region (832B).

[0282] In the third region (832C) of the insulating structure (832b), the first intermediate layer (836b) may be formed by a first layer (838a), a second layer (838b), and a third layer (838c) stacked in sequence; in the second region (832B) of the insulating structure (832b), the first intermediate layer (836b) may be formed by a second layer (838b) and a third layer (838c) stacked in sequence; and in the first region (832A) of the insulating structure (832b), the first intermediate layer (836b) may be formed by a third layer (838c).

[0283] In one example, the first layer (838a), the second layer (838b), and the third layer (838c) of the first intermediate layer (836b) may each contain the same material, for example, hafnium oxide. In another example, at least two of the first layer (838a), the second layer (838b), and the third layer (838c) of the first intermediate layer (836b) may be formed of different materials.

[0284] The first intermediate layer (836b) may include a maximum thickness portion formed by the first to third layers (838a, 838b, 838c), an intermediate thickness portion formed by the second and third layers (838b, 838c), and a minimum thickness portion formed by the third layer (838c). Depending on the thickness difference according to the position of the first intermediate layer (836b), a thickness difference may occur in the first to third regions (832A, 832B, 832C) of the insulating structure (832b), as shown in FIG. 33.

[0285] In another embodiment, the separation structure (115) in FIG. 33 and FIG. 34 may be modified into a separation structure (115') comprising a first layer (115a') and a second layer (115b') as in FIG. 4a, and the insulating structure (832a in FIG. 33 or 832b in FIG. 34) comprising the first region (832A), the second region (832B) and the third region (832C) having different thicknesses as in FIG. 33 and FIG. 34 may be modified into an insulating structure comprising a portion extending into the opening (112' in FIG. 4a) extending in a direction toward the first surface (106s1) from the second surface (106s2) of the second substrate (106) as in FIG. 4a.

[0286] In another embodiment, in FIG. 33 and FIG. 34, the second surface (106s2) of the second substrate (106) may be substantially flat, but may be modified into a second surface (106s2') having an uneven structure as described in FIG. 4b.

[0288] Next, with reference to FIGS. 35 and FIGS. 36, a modified example of the image sensor (1e) described in FIGS. 19 to 23 will be described. FIG. 35 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIG. 36 is a schematic cross-sectional view showing regions taken along the Ih-Ih' and IIh-IIh' lines of FIG. 35 to explain an example of an image sensor according to another embodiment of the present invention.

[0289] Referring to FIGS. 35 and 36, the image sensor (1h) in the modified example may include a grid structure (960) that can replace the grid structure (560 in FIGS. 19 and 20) described above, and an insulating structure (532a') that can replace the insulating structure (532a in FIGS. 19 and 20) described above.

[0290] In the top view, the grid structure (560) described in FIGS. 19 and 20 may be replaced with a grid structure (960) that further includes a portion crossing each of the color filters (570) in the X and Y directions. For example, the grid structure (960) may include a first portion (960a) crossing between the color filters (570) and a second portion (960b) crossing each of the color filters (570) in the X and Y directions. The second portion (960b) of the grid structure (960) may cross one of the first color filters (570a) along the X direction.

[0291] The insulating structure (532a') may include a first region (532A') and a second region (532B') having a thickness greater than that of the first region (532A'), as described in FIG. 20.

[0292] The portions adjacent to the grid structure (960) in the third color filters (570c), the second color filters (570b), and the first color filters (570a), and the grid structure (960) may be placed on the second region (532B') of the insulating structure (532a'), and the central portions of each of the first color filters (570a) surrounded by the grid structure (960) in a top view may be placed on the first region (532A') of the insulating structure (532a').

[0293] The region where the thickness changes in the insulating structure (532a'), that is, the boundary region (532br') between the first region (532A') and the second region (532B'), may overlap perpendicularly with the first color filters (570a) and be spaced apart from the grid structure (560).

[0294] In one example, the thickness of the insulating structure (532a') may vary according to the thickness change of the second intermediate layer (542a) as in FIG. 20.

[0295] In another example, the thickness of the insulating structure (532a') may vary according to the thickness change of the first intermediate layer (536b) as in FIG. 21.

[0297] Next, with reference to FIGS. 37 and 38, a modified example of the image sensor (1f) described in FIGS. 24 through 28 will be described. FIG. 37 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIG. 38 is a schematic cross-sectional view showing regions taken along the lines Ii-Ii' and IIi-IIi' of FIG. 37 to explain an example of an image sensor according to another embodiment of the present invention.

[0298] Referring to FIGS. 37 and 38, the image sensor (1i) in the modified example may include a grid structure (960) that can replace the grid structure (560 in FIGS. 24 and 25) described above, and an insulating structure (632a') that can replace the insulating structure (632a in FIGS. 24 and 25) described above.

[0299] In the top view, the grid structure (560) described in FIGS. 24 and 25 can be replaced with the grid structure (960) as described in FIGS. 35 and 36.

[0300] The insulating structure (632a') may include a first region (632A') and a second region (632B') having a thickness greater than that of the first region (632A'), as described in FIG. 25.

[0303] The portions adjacent to the grid structure (960) in the first color filters (570a), the second color filters (570b), and the third color filters (570c), and the grid structure (960) may be placed on the second region (632B') of the insulating structure (632a'), and the central portions of each of the third color filters (570c) surrounded by the grid structure (960) in a top view may be placed on the first region (632A') of the insulating structure (632a').

[0304] The region where the thickness changes in the insulating structure (632a'), that is, the boundary region (632br') between the first region (632A') and the second region (632B'), may overlap perpendicularly with the third color filters (570c) and be spaced apart from the grid structure (960).

[0305] In one example, the thickness of the insulating structure (632a') may vary according to the thickness change of the second intermediate layer (642a) as in FIG. 25.

[0306] In another example, the thickness of the insulating structure (632a') may vary according to the thickness change of the first intermediate layer (636b) as in FIG. 26.

[0308] Next, with reference to FIGS. 39 and FIGS. 40, a modified example of the image sensor (1fa) described in FIGS. 29 to 31 will be described. FIG. 39 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIG. 40 is a schematic cross-sectional view showing regions taken along the lines Ij-Ij' and IIj-IIj' of FIG. 39 to explain an example of an image sensor according to another embodiment of the present invention.

[0309] Referring to FIGS. 39 and 40, the image sensor (1j) in the modified example may include a grid structure (960) that can replace the grid structure (560 in FIGS. 29 and 30) described above, and an insulating structure (732a') that can replace the insulating structure (732a in FIGS. 29 and 30) described above.

[0310] In the top view, the grid structure (560) described in FIGS. 24 and 25 can be replaced with the grid structure (960) as described in FIGS. 35 and 36.

[0311] The insulating structure (732a') may include a first region (732A') and a second region (732B') having a thickness greater than that of the first region (732A'), as described in FIG. 30.

[0312] The portions adjacent to the grid structure (960) in the second color filters (570b) and the third color filters (570c), the portions adjacent to the grid structure (960) in the first color filters (570a), and the grid structure (960) may be placed on the second region (732B') of the insulating structure (732a'), and the central portions of each of the third color filters (570c) surrounded by the grid structure (960) in the top view may be placed on the third region (732C') of the insulating structure (732a'), and the central portions of each of the first color filters (570a) surrounded by the grid structure (960) in the top view may be placed on the first region (732A') of the insulating structure (732a').

[0313] The region where the thickness changes in the insulating structure (732a'), that is, the first boundary region (732br1') between the first region (732A') and the second region (732B'), may overlap vertically with the first color filters (570a) and be spaced apart from the grid structure (960), and the second boundary region (732br2') between the second region (732B') and the third region (732C') may overlap vertically with the third color filters (570c) and be spaced apart from the grid structure (960).

[0314] In one example, the thickness of the insulating structure (732a') may vary according to the thickness change of the second intermediate layer (742a) as in FIG. 30.

[0315] In another example, the thickness of the insulating structure (732a') may vary according to the thickness change of the first intermediate layer (736b) as in FIG. 31.

[0317] Next, with reference to FIGS. 41 and FIGS. 42, a modified example of the image sensor (1g) described in FIGS. 32 to 34 will be described. FIG. 41 is a top view schematically showing an image sensor according to another embodiment of the present invention, and FIG. 41 is a schematic cross-sectional view showing regions taken along the Ik-Ik' and IIk-IIk' lines of FIG. 40 to explain an example of an image sensor according to another embodiment of the present invention.

[0318] Referring to FIGS. 40 and 41, the image sensor (1k) in the modified example may include a grid structure (960) that can replace the grid structure (560 in FIGS. 32 and 33) described above, and an insulating structure (832a') that can replace the insulating structure (832a in FIGS. 32 and 33) described above.

[0319] In the top view, the grid structure (560) described in FIGS. 32 and 33 can be replaced with the grid structure (960) as described in FIGS. 35 and 36.

[0320] The insulating structure (832a') may include a first region (832A'), a second region (832B') having a thickness greater than that of the first region (832A'), and a third region (832C') having a thickness greater than that of the second region (832B'), as described in FIG. 33.

[0321] The portions adjacent to the grid structure (960) in the third color filters (570c) and the second color filters (570b), the portions adjacent to the grid structure (960) in the first color filters (570a), and the grid structure (960) may be placed on the third region (832C') of the insulating structure (832a'), and the central portions of each of the second color filters (570b) surrounded by the grid structure (960) in the top view may be placed on the second region (832B') of the insulating structure (832a'), and the central portions of each of the first color filters (570a) surrounded by the grid structure (960) in the top view may be placed on the first region (832A') of the insulating structure (832a').

[0322] The region where the thickness changes in the insulating structure (832a'), that is, the first boundary region (832br1') between the first region (832A') and the second region (832B'), may overlap vertically with the first color filters (570a) and be spaced apart from the grid structure (960), and the second boundary region (832br2') between the second region (832B') and the third region (832C') may overlap vertically with the second color filters (570b) and be spaced apart from the grid structure (960).

[0323] In one example, the thickness of the insulating structure (832a') may vary according to the thickness change of the second intermediate layer (842a) as in FIG. 33.

[0324] In another example, the thickness of the insulating structure (832a') may vary according to the thickness change of the first intermediate layer (836b) as in FIG. 34.

[0326] Next, with reference to FIG. 43, an image sensor according to another embodiment of the present invention will be described. FIG. 43 is a schematic top view showing an image sensor according to another embodiment of the present invention.

[0327] Referring to FIG. 43, the image sensor (1l) may include the first chip structure (3) which is substantially the same as that described in FIG. 2.

[0328] The image sensor (1l) may further include a second chip structure (1003) on the first chip structure (3). The second chip structure (1003) may be an image sensor chip.

[0329] The second chip structure (1003) may include a second substrate (106) having a first surface (106s1) and a second surface (106s2) facing each other, a device isolation film (118) disposed on the first surface (106s1) of the second substrate (106) and defining an active region, a second circuit element (124) and a second wiring structure (127) disposed between the first surface (106s1) of the second substrate (106) and the first chip structure (3), and a second insulating layer (130) covering the second circuit element (124) and the second wiring structure (127) between the first surface (106s1) of the second substrate (106) and the first chip structure (3). The first surface (106s1) of the second substrate (106) may face the first chip structure (3). The second substrate (106) may be a semiconductor substrate. For example, the second substrate (106) may be a substrate formed of a semiconductor material, for example, a single-crystal silicon substrate.

[0330] The image sensor (1l) may further include photoelectric conversion elements (PDs) as described in FIG. 2.

[0331] The second chip structure (1003) may further include through electrode structures (1115). The through electrode structures (1115) may include a conductive pattern (1115b) and an insulating spacer (1115a) on the side of the conductive pattern (1115b). The through electrode structures (1115) may be positioned between the photoelectric conversion elements (PD) and may penetrate the second substrate (106).

[0332] The above second chip structure (1003) may further include an insulating structure (1032a) having different thickness regions.

[0333] The second chip structure (1003) may further include an insulating layer (1065) disposed on the insulating structure (1032a) and color filters (1070) that can be embedded within the insulating layer (1065). The color filters (1070) may include a blue color filter (1070a) capable of passing blue wavelength light so that the blue wavelength reaches the photoelectric conversion element (SD), and a red color filter (1070b) capable of passing red wavelength light so that the red wavelength reaches the photoelectric conversion element (PD).

[0334] The second chip structure (1003) may further include first electrodes (1076) disposed on the insulating layer (1065), an insulating layer (1074) capable of surrounding the sides of the first electrodes (1076), and rear contact plugs (1072) capable of electrically connecting the first electrodes (1076) and the conductive patterns (1115b). The first electrodes (1076) may include portions that overlap with the color filters (1070).

[0335] The first electrodes (1076) may be transparent electrodes. For example, the first electrodes (1076) may be made of a transparent conductive material such as ITO, IZO, ZnO, SnO2, ATO (antimony-doped tin oxide), AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO2, or FTO (fluorine-doped tin oxide).

[0336] The second chip structure (1003) may further include a photoelectric layer (1082) disposed on the first electrodes (1076), a second electrode (1084) disposed on the photoelectric layer (1082), and microlenses (1090) disposed on the second electrode (1084).

[0337] In one example, the photoelectric layer (1082) may be an organic photoelectric layer. For example, the photoelectric layer (1082) may be an organic photoelectric layer formed from an organic material that undergoes photoelectric conversion only at a specific wavelength of light. For example, the photoelectric layer (1082) may include a p-type layer in which the main carrier is a hole and an n-type layer in which the main carrier is an electron. The photoelectric layer (1082) may generate a charge in response to light of a specific wavelength band, and in one embodiment, may generate a charge in response to green light. In this case, light of colors other than green (e.g., blue, red) may be transmitted to the photoelectric conversion elements (SD) through the color filters (1070).

[0338] The second electrode (1084) may be formed as a transparent electrode. For example, the second electrode (1084) may be formed of ITO, IZO, ZnO, SnO2, ATO (antimony-doped tin oxide), AZO (Al-doped zinc oxide), GZO (gallium-doped zinc oxide), TiO2, or FTO (fluorine-doped tin oxide).

[0339] In one example, the photoelectric layer (1082) and the first and second electrodes (1076, 7084) may constitute an organic photoelectric device or an organic photoelectric conversion device. The charge generated in response to green light in the photoelectric layer (1082) may be accumulated in storage node regions through the first electrodes (1076), the back contact plugs (1072), the conductive patterns (1115b) within the through electrode structures (1115), and the front contact plugs (1010).

[0340] The insulating structure (1032a) may include a plurality of layers stacked in sequence. The insulating structure (1032a) may include an anti-reflection layer that can provide a high transmittance of incident light by adjusting the refractive index. For example, the insulating structure (1032a) may include at least three layers. Accordingly, the insulating structure (1032a) may also be referred to as an anti-reflection structure.

[0341] The insulating structure (1032a) may include a lower layer (1034), an intermediate layer (1036a, 1042a) on the lower layer (1034), and an upper layer (1048) on the intermediate layer (1036a, 1042a).

[0342] The lower layer (1034) and the upper layer (1048) may be substantially the same as the lower layer (134) and the upper layer (148) described in FIG. 2. For example, the upper layer (1048) may include a first layer (1050a) and a second layer (1050b) stacked in sequence.

[0343] The above intermediate layer (1036a, 1042a) may include a first intermediate layer (1036a) and a second intermediate layer (1042a) stacked in sequence.

[0344] The first intermediate layer (1036a) above may be substantially the same as the first intermediate layer (136a) described in FIG. 2.

[0345] The second intermediate layer (1042a) may be substantially the same as the second intermediate layer (142a) described in FIG. 2. For example, the second intermediate layer (1042a) may include a first layer (1044a) and a second layer (1044b) stacked in sequence.

[0346] The insulating structure (1032a) may include a first region (1032A) having a first thickness and a second region (1032B) having a second thickness greater than the first thickness.

[0347] In the second region (1032B) of the insulating structure (1032a), the second intermediate layer (1042a) may be formed by a first layer (1044a) and a second layer (1044b) stacked in sequence, and in the first region (1032A) of the insulating structure (1032a), the second intermediate layer (1042a) may be formed by the second layer (1044b). Accordingly, the second intermediate layer (1042a) may include a thick portion formed by the first and second layers (1044a, 1044b) and a thin portion formed by the second layer (1044b). According to the thickness difference according to the position of the second intermediate layer (1042a) as described above, a thickness difference may occur between the first and second regions (1032A, 1032B) of the insulating structure (1032a).

[0348] In the insulating structure (1032a), the first region (1032A) may be positioned below the blue color filter (1070a), and the second region (1032B) may be positioned below the red color filter (1070b).

[0349] In the insulating structure (1032a), the boundary region (1032br) between the first region (1032A) and the second region (1032B), where the thickness of the insulating structure (1032a) changes, may be positioned below the edge portion of the blue color filter (1070a).

[0351] Next, with reference to FIG. 44, an image sensor according to another embodiment of the present invention will be described. FIG. 44 is a schematic top view showing an image sensor according to another embodiment of the present invention.

[0352] Referring to FIG. 44, the boundary region (1032br) between the first region (1032A) and the second region (1032B), where the thickness of the insulating structure (1032a) described in FIG. 43 changes, can be transformed into a boundary region (1032br') positioned below the edge portion of the red color filter (1070b).

[0354] Next, with reference to FIG. 45, an image sensor according to another embodiment of the present invention will be described. FIG. 45 is a schematic top view showing an image sensor according to another embodiment of the present invention.

[0355] Referring to FIG. 44, the boundary region (1032br) between the first region (1032A) and the second region (1032B), where the thickness of the insulating structure (1032a) described in FIG. 43 changes, can be modified so as not to overlap perpendicularly with the color filters (1070) placed below the edge portion of the red color filter (1070b). For example, the rear contact plugs (1072) can penetrate the boundary region between the first region (1032A) and the second region (1032B), where the thickness of the insulating structure (1032a) changes.

[0357] With reference to FIGS. 46 and FIGS. 47, an image sensor according to an embodiment of the present invention will be described. FIG. 46 is a graph for explaining the light transmittance of an image sensor according to an embodiment of the present invention, and FIG. 47 is a graph showing the amount of light absorbed by a photodiode in an image sensor according to an embodiment of the present invention.

[0358] Referring to FIGS. 46 and FIGS. 47, the line labeled A in FIG. 46 represents the light transmittance in an image sensor with a constant thickness of an insulating structure, which may be an anti-reflective layer, and the line labeled A in FIG. 47 represents the amount of light that passes through the insulating structure with a constant thickness and is absorbed by a photodiode.

[0359] The line labeled B in FIG. 46 represents the transmittance of light passing through the first region (332A) of the insulating structure (332a) having a first thickness under the blue color filter (170a) of the image sensor (1c) described in FIG. 10 and FIG. 11, and the line labeled B in FIG. 47 may represent the amount of light that passes through the first region (332A) of the insulating structure (332a) having a first thickness under the blue color filter (170a) of the image sensor (1c) and is absorbed by the photodiode (PD).

[0360] The line labeled C in FIG. 46 represents the transmittance of light passing through the second region (332B) of the insulating structure (332a) having a second thickness under the green color filter (170b) of the image sensor (1c), and the line labeled C in FIG. 47 represents the amount of light passing through the second region (332B) of the insulating structure (332a) under the green color filter (170b) of the image sensor (1c) that is absorbed by the photodiode (PD).

[0361] The line labeled D in FIG. 46 represents the transmittance of light passing through the third region (332C) of the insulating structure (332a) having a third thickness under the red color filter (170c) of the image sensor (1c), and the line labeled D in FIG. 47 represents the amount of light passing through the third region (332C) of the insulating structure (332a) under the red color filter (170c) of the image sensor (1c) that is absorbed by the photodiode (PD).

[0362] As shown in FIGS. 46 and 47, by varying the thickness of the intermediate layer (336a, 342a) of the insulating structure (332a) according to the position, the transmittance of light passing through the insulating structure (332a) can be optimized according to the color type of the color filters (170), and accordingly, it can be seen that the amount of light absorbed by the photodiode (PD) under the blue color filter (170a) is improved by about 4.7%, and the amount of light absorbed by the photodiode (PD) under the red color filter (170c) is improved by about 1.3%.

[0363] Therefore, the sensitivity of image sensors according to embodiments of the present invention can be improved.

[0365] Hereinafter, with reference to FIGS. 1 to FIGS. 45, an exemplary example of a method for forming the insulating structures described above will be explained.

[0366] First, with reference to FIG. 48, a method for forming an image sensor according to embodiments of the present invention will be described. FIG. 48 is a process flow diagram illustrating a method for forming an image sensor according to embodiments of the present invention.

[0367] Referring to FIG. 48, forming an insulating structure that may be an anti-reflective layer in an image sensor may include the step of forming a lower layer (S10), the step of forming an intermediate layer comprising two or more regions having different thicknesses (S20), and the step of forming an upper layer (S30).

[0369] Next, with reference to FIGS. 1 to 45, exemplary examples of methods for forming the insulating structures described above, such as the insulating structure (132a) of FIG. 2 and the insulating structure (132b) of FIG. 3, will be described.

[0370] First, regarding an example of a method for forming the insulating structure (132a) described with reference to FIG. 2, it will be described with reference to FIG. 49 and FIG. 50a to 50c. FIG. 49 is a process flow diagram showing an example of a method for forming an image sensor according to embodiments of the present invention, and FIG. 50a to 50c are schematic cross-sectional views showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIG. 1.

[0371] Referring to FIG. 49 and FIG. 50a, a lower layer (134) can be formed (S10). The lower layer (134) can be formed on the second surface (106s2) of the second substrate (106 in FIG. 2).

[0372] A first intermediate layer (136a) can be formed (S27). The first intermediate layer (136a) can be formed on the lower layer (134).

[0373] Referring to FIG. 49 and FIG. 50b, a first layer (144a) can be formed on the first intermediate layer (136a), a mask pattern (139) having an opening can be formed on the first layer (144a), and the first layer (144a) can be etched using the mask pattern (139) as an etching mask. Thus, the first layer (144a) described in FIG. 2 can be formed.

[0374] Referring to FIG. 49 and FIG. 50c, a second layer (144b) covering the first layer (144a) can be formed on the first intermediate layer (136a). Here, the first and second layers (144a, 144b) can constitute the second intermediate layer (142a) described in FIG. 2. Thus, the second intermediate layer (142a) can be formed including two or more regions having different thicknesses (S32).

[0375] An upper layer (148) can be formed (S40). The upper layer (148) may include a first layer (150a) and a second layer (150b) that are sequentially stacked on the second intermediate layer (142a). Thus, an insulating structure (132a) as in FIG. 2 can be formed.

[0377] Next, with reference to FIGS. 1 to 45, exemplary examples of methods for forming the insulating structures described above, such as the insulating structure (132a) of FIG. 2 and the insulating structure (132b) of FIG. 3, will be described.

[0378] Next, an example of a method for forming the insulating structure (132b) described with reference to FIG. 3 will be described with reference to FIG. 51 and FIG. 52a to 52c. FIG. 51 is a process flow diagram showing an example of a method for forming an image sensor according to embodiments of the present invention, and FIG. 52a to 52c are schematic cross-sectional views showing regions taken along the lines Ia-Ia' and IIa-IIa' of FIG. 1.

[0379] Referring to FIG. 51 and FIG. 52a, a lower layer (134) can be formed (S10). The lower layer (134) can be formed on the second surface (106s2) of the second substrate (106 in FIG. 2).

[0380] A first layer (138a) can be formed on the lower layer (134), a mask pattern (139') having an opening can be formed on the first layer (138a), and the first layer (138a) can be etched using the mask pattern (139') as an etching mask. Thus, the first layer (138a) described in FIG. 3 can be formed.

[0381] Referring to FIGS. 51 and FIGS. 52b, a second layer (138b) covering the first layer (138a) can be formed on the lower layer (134). Here, the first and second layers (138a, 138b) can constitute the first intermediate layer (136b) described in FIG. 3. Thus, the first intermediate layer (136b) can be formed including two or more regions having different thicknesses (S25).

[0382] Referring to FIG. 51 and FIG. 52c, a second intermediate layer (142b) can be formed on the first intermediate layer (136a) (S30). An upper layer (148) can be formed (S40). The upper layer (148) may include a first layer (150a) and a second layer (150b) that are sequentially stacked on the second intermediate layer (142b). Thus, an insulating structure (132b) as in FIG. 3 can be formed.

[0384] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

Claim 1 An image sensor comprising: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; a plurality of color filters disposed on the insulating structure; and a grid structure disposed on the insulating structure, wherein at least a portion thereof is disposed between the plurality of color filters, the plurality of color filters comprising a first color filter and a second color filter of different colors, the insulating structure comprising a first region having a first thickness and a second region having a second thickness different from the first thickness, and the boundary region between the first region and the second region in the insulating structure vertically overlaps with the first color filter and is misaligned with the vertical center axis of the grid structure. Claim 2 An image sensor according to claim 1, wherein the first thickness is smaller than the second thickness, and in the insulating structure, the first region overlaps perpendicularly with the first color filter and does not overlap perpendicularly with the second color filter, and the first color filter is a blue color filter and the second color filter is a green color filter. Claim 3 In claim 1, the color filters further include a third color filter of a color different from the first and second color filters, wherein the first color filter is a blue color filter, the second color filter is a green color filter, and the third color filter is a red color filter, and in the insulating structure, the first region overlaps perpendicularly with the first color filter, and the second region overlaps perpendicularly with the grid structure, the second color filter, and the third color filter, an image sensor. Claim 4 In claim 3, each of the above color filters is an image sensor that overlaps perpendicularly with a plurality of the above photodiodes. Claim 5 An image sensor according to claim 1, wherein the color filters further include a third color filter of a color different from the first and second color filters, wherein the first color filter is a blue color filter, the second color filter is a green color filter, and the third color filter is a red color filter, and the insulating structure further includes a third region having a third thickness greater than the second thickness, wherein the first region overlaps perpendicularly with at least a portion of the first color filter, the second region overlaps perpendicularly with at least the second color filter and the grid structure, and the third region overlaps perpendicularly with at least a portion of the third color filter. Claim 6 In claim 1, the color filters further include a third color filter of a color different from the first and second color filters, wherein the first color filter is a blue color filter, the second color filter is a green color filter, and the third color filter is a red color filter, and the insulating structure further includes a third region having a third thickness greater than the second thickness, wherein the first region overlaps perpendicularly with at least a part of the first color filter, the second region overlaps perpendicularly with at least a part of the second color filter, and the third region overlaps perpendicularly with the grid structure and the third color filter, an image sensor. Claim 7 An image sensor comprising: a substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; and a plurality of color filters disposed on the insulating structure, wherein the plurality of color filters include a first color filter and a second color filter of different colors, and the insulating structure includes a lower layer, an intermediate layer and an upper layer stacked in sequence, wherein the lower layer has a uniform thickness, the upper layer has a uniform thickness, and the intermediate layer includes two or more regions having different thicknesses. Claim 8 In claim 7, the intermediate layer comprises a first intermediate layer and a second intermediate layer on the first intermediate layer, the first intermediate layer comprises two or more regions having different thicknesses, and the second intermediate layer has a uniform thickness image sensor. Claim 9 An image sensor according to claim 7, wherein the intermediate layer comprises a first intermediate layer and a second intermediate layer on the first intermediate layer, the upper layer comprises at least two layers, either of the first and second intermediate layers comprises two or more regions having different thicknesses, and either of the at least two layers comprises the same material as the lower layer, and the remaining layer comprises the same material as the first intermediate layer. Claim 10 A substrate having a first surface and a second surface facing each other; photodiodes disposed within the substrate; a separation structure disposed between the photodiodes within the substrate; a circuit and wiring structure disposed below the first surface of the substrate; an insulating structure disposed on the second surface of the substrate; and a plurality of color filters disposed on the insulating structure. An image sensor comprising a grid structure disposed on the insulating structure, wherein at least a portion thereof is disposed between the plurality of color filters, the grid structure having at least a portion thereof vertically overlapped with at least a portion thereof of the separating structure, the plurality of color filters having different colors including a blue color filter, a green color filter, and a red color filter, the insulating structure having a lower layer, an intermediate layer, and an upper layer stacked in order, the lower layer having a uniform thickness, the upper layer having a uniform thickness, the intermediate layer having two or more regions having different thicknesses, the minimum thickness of the insulating structure overlapping with the blue color filter being smaller than the maximum thickness of the insulating structure overlapping with the red color filter, and the lower surface of the grid structure being disposed at a constant height level.

Images