Image sensor and method for manufacturing the same

Abstract

The present invention provides an image sensor that is easily integrated and a method for manufacturing the same. [Solution] The image sensor according to the present invention includes a semiconductor substrate on which a plurality of photoelectric conversion units are defined, a plurality of color filters on the semiconductor substrate, and a grid structure disposed between adjacent color filters, wherein the grid structure includes a fence gap defined by a gap insulating film, a gap insulating film surrounding the fence gap, and a support member disposed on the gap insulating film, wherein the fence gap includes an upper curved surface, a first side wall, a second side wall, and a lower surface, the gap insulating film completely covers the upper curved surface, the first side wall, and the second side wall of the fence gap, the gap insulating film covers 50% or more of the lower surface of the fence gap, and the support member is spaced apart from the fence gap.

Description

Technical Field

[0001] The present invention relates to an image sensor and a method for manufacturing the same, and more particularly to a CMOS image sensor and a method for manufacturing the same.

Background Art

[0002] An image sensor is a semiconductor device that converts an optical image into an electrical signal. Recently, with the development of the computer and communication industries, the demand for image sensors with improved performance in various fields such as digital cameras, video cameras, PCS (Personal Communication System), game devices, security cameras, and medical micro cameras has been increasing.

[0003] As semiconductor devices are highly integrated, image sensors are also highly integrated. Therefore, the size of each pixel is also reduced. As a result, an image sensor having low crosstalk and high sensitivity even in a fine area is required.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above prior art, and an object of the present invention is to provide an image sensor and a method for manufacturing the same that are easily highly integrated. Another object of the present invention is to provide an image sensor and a method for manufacturing the same having improved sensitivity. Furthermore, an object of the present invention is to provide an image sensor that is stable and reduces crosstalk by providing a constant grid air gap, and a method for manufacturing the same.

[0006] The technical problems that this invention aims to solve are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] An image sensor according to one aspect of the present invention made to achieve the above objective includes a semiconductor substrate in which a plurality of photoelectric conversion units are defined, a plurality of color filters on the semiconductor substrate, and a grid structure disposed between adjacent color filters, wherein the grid structure includes a fence gap defined by a gap insulating film, a gap insulating film surrounding the fence gap, and a support member disposed on the gap insulating film, wherein the fence gap includes a curved upper gap surface, a first side wall extending from the upper gap surface toward the semiconductor substrate, a second side wall facing the first side wall, and a lower surface including a flat surface between the first side wall and the second side wall, wherein the gap insulating film completely covers the upper gap surface, the first side wall, and the second side wall of the fence gap, the gap insulating film covers 50% or more of the lower surface of the fence gap, and the support member is spaced apart from the fence gap.

[0008] To achieve the above objective, an image sensor according to another aspect of the present invention includes a semiconductor substrate in which a plurality of photoelectric conversion units are defined, a plurality of color filters on the semiconductor substrate, and a grid structure disposed between adjacent color filters, wherein the grid structure includes an intervening region grid structure and an intersecting region grid structure, wherein the grid structure includes a fence gap defined by a gap insulating film, a gap insulating film surrounding the fence gap, and a support member disposed on the gap insulating film, wherein the fence gap includes a curved upper gap surface, a first side wall extending from the upper gap surface toward the semiconductor substrate, a second side wall facing the first side wall, and a lower surface including a flat surface between the first side wall and the second side wall, wherein the gap insulating film completely covers the upper gap surface, the first side wall, and the second side wall of the fence gap, the gap insulating film covers 50% or more of the lower surface of the fence gap, and the intersecting region grid structure is separated by the gap insulating film.

[0009] To achieve the above objective, an image sensor according to yet another aspect of the present invention includes a semiconductor substrate having a first surface and a second surface facing each other and having a plurality of photoelectric conversion units defined thereon, a transmission gate disposed on the first surface, a stationary charge film disposed on the second surface, a protective film on the stationary charge film, a back insulating film on the protective film, a capping film on the back insulating film, a plurality of color filters on the capping film, and a grid structure disposed between adjacent color filters, wherein the grid structure includes a fence gap defined by a gap insulating film, a gap insulating film surrounding the fence gap, and a support member disposed on the gap insulating film, wherein the fence gap includes a curved upper surface of the gap having a curved surface, a first side wall extending from the upper surface of the gap toward the semiconductor substrate, a second side wall facing the first side wall, and a lower surface including a flat surface between the first side wall and the second side wall, wherein the gap insulating film completely covers the upper surface of the gap, the first side wall and the second side wall of the fence gap, the gap insulating film covers 50% or more of the lower surface of the fence gap, and the support member is spaced apart from the fence gap. [Effects of the Invention]

[0010] According to the present invention, the image sensor has a grid structure placed between color filters, and the grid structure can include a grid gap inside. The grid gap can reduce the crosstalk of the image sensor.

[0011] According to the present invention, the image sensor has a grid structure arranged between color filters, and some of the grid structures may include a shield fence film. Through this, the reliability and optical performance of the image sensor can be improved. [Brief explanation of the drawing]

[0012] [Figure 1] This is a plan view of an image sensor according to some embodiments of the present invention. [Figure 2]This is a cross-sectional view taken along the line A-A' in Figure 1. [Figure 3] This is a cross-sectional view taken along the line B-B' in Figure 1. [Figure 4] This is an enlarged cross-sectional view of M in Figure 2. [Figure 5] This is an enlarged cross-sectional view of N in Figure 3. [Figure 6] This figure shows an image sensor according to some embodiments, and is a cross-sectional view corresponding to an enlarged cross-sectional view of M in Figure 2. [Figure 7] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of N in Figure 3. [Figure 8] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of X in Figure 2. [Figure 9] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of Y in Figure 3. [Figure 10] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of X in Figure 2. [Figure 11] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of Y in Figure 3. [Figure 12] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of X in Figure 2. [Figure 13] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of Y in Figure 3. [Figure 14] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of X in Figure 2. [Figure 15] This figure shows an image sensor according to one embodiment, and is a cross-sectional view corresponding to an enlarged cross-sectional view of Y in Figure 3. [Figure 16]A diagram showing an image sensor according to some embodiments, which is a cross-sectional view corresponding to an enlarged cross-sectional view of M in FIG. 2. [Figure 17] A diagram showing an image sensor according to some embodiments, which is a cross-sectional view corresponding to an enlarged cross-sectional view of N in FIG. 3. [Figure 18] A diagram showing an image sensor according to some embodiments, which is a cross-sectional view corresponding to an enlarged cross-sectional view of M in FIG. 2. [Figure 19] A diagram showing an image sensor according to some embodiments, which is a cross-sectional view corresponding to an enlarged cross-sectional view of N in FIG. 3. [Figure 20] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of Q in FIG. 2. [Figure 21] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of R in FIG. 2. [Figure 22] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of Q in FIG. 2. [Figure 23] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of R in FIG. 2. [Figure 24] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of Q in FIG. 2. [Figure 25] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of R in FIG. 2. [Figure 26] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of Q in FIG. 2. [Figure 27] A diagram showing a method of manufacturing an image sensor according to some embodiments of the present invention, which is an enlarged view corresponding to an enlarged view of R in FIG. 2. [Figure 28]This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 29] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 30] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 31] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 32] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 33] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 34] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 35] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 36] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 37] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 38] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 39] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 40] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 41] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 42] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 43] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 44] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 45] This is a view showing a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 46] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 47] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 48] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 49] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 50] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 51] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Figure 52] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of Q in Figure 2. [Figure 53] This figure shows a method for manufacturing an image sensor according to some embodiments of the present invention, and is an enlarged view corresponding to an enlarged view of R in Figure 2. [Modes for carrying out the invention]

[0013] The present invention will be described in detail below by referring to the drawings to illustrate embodiments of the present invention.

[0014] Figure 1 is a plan view of an image sensor according to one embodiment of the present invention. Figure 2 is a cross-sectional view taken along the line A-A' in Figure 1. Figure 3 is a cross-sectional view taken along the line B-B' in Figure 1. Figure 4 is an enlarged cross-sectional view of M in Figure 2. Figure 5 is an enlarged cross-sectional view of N in Figure 3.

[0015] Referring to Figures 1, 2, 3, and 4, a substrate 100 is provided. The substrate 100 is, for example, a silicon single crystal wafer, a silicon epitaxial layer, or an SOI (siliconon insulator) substrate. For example, the substrate 100 is doped with an impurity having a first conductivity type (e.g., type P). The substrate 100 includes a first surface 100A and a second surface 100B that are opposite to each other. The first surface 100A is separated from the second surface 100B in a first direction D1. The second surface 100B is separated from the first surface 100A in a second direction D2.

[0016] The image sensor according to the present invention includes a plurality of pixel regions PX. As an example, it includes first, second, third, and fourth pixel regions PX1, PX2, PX3, and PX4 arranged in order along a clockwise direction. The first and second pixel regions PX1 and PX2 are arranged side by side along a third direction D3, and the third and fourth pixel regions PX3 and PX4 are also arranged side by side along the third direction D3. The third direction D3 is parallel to the second surface 100B of the substrate 100. The second and third pixel regions PX2 and PX3 are arranged side by side along a fourth direction D4, and the first and fourth pixel regions PX1 and PX4 are also arranged side by side along the fourth direction D4. The fourth direction D4 is parallel to the second surface 100B of the substrate 100 and intersects with the third direction D3.

[0017] The element isolation pattern 13 is located within an isolation trench DTR that extends from the first surface 100A toward the second surface 100B. In plan view, the element isolation pattern 13 has a mesh shape in which lines extending in the third and fourth directions D3 and D4 intersect.

[0018] An element isolation pattern 13 is arranged on the first substrate 1 to isolate the photoelectric conversion unit PD. The photoelectric conversion unit PD is doped with an impurity of a second conductivity type, which is opposite to the first conductivity type. The second conductivity type is, for example, N-type. The N-type impurity region formed by doping the photoelectric conversion unit PD forms a PN junction with the adjacent P-type impurity region of the substrate 100 to provide a photodiode.

[0019] The grid structure 71 is arranged so as to overlap the element separation pattern 13 with the second direction D2. The grid structure 71 includes a grid structure 71IR in the intervening region and a grid structure 71CR in the crossing region.

[0020] The grid structure 71 includes a fence gap 712 defined by a gap insulating film 711, a gap insulating film 711 surrounding the fence gap 712, and a support member 713 positioned on the gap insulating film 711. The support member 713 is spaced apart from the fence gap 712.

[0021] A capping film 50 is provided on the grid structure 71. The capping film 50 surrounds the top and sides of the grid structure. The capping film 50 is in contact with the color filters CF1 and CF2. The capping film 50 contains a metal oxide or silicon. The capping film 50 contains at least one of the following: a single film of a metal oxide such as Al2O3, a multiple film of silicon oxide / Al2O3, or a single or multiple film of TiO2, Ta2O5, Ta2O3, HfO, ZrO, Si3N4, SiCN, etc.

[0022] The intervening region grid structure 71IR is defined as a grid structure superimposed on the region between two adjacent pixel regions PX. The intersecting region grid structure 71CR is defined as a grid structure superimposed on the region between four adjacent pixel regions PX. The intervening region IR and the intersecting region CR are contiguous.

[0023] A shallow element isolation film 5 is positioned adjacent to the first surface 100A of the substrate 100. The element isolation pattern 13 penetrates the shallow element isolation film 5. A shallow element isolation trench STR is provided recessed into the interior of the substrate 100 from the first surface 100A of the substrate 100, and the shallow element isolation film 5 fills the shallow element isolation trench STR. The shallow element isolation film 5 is positioned adjacent to the first surface 100A of the substrate. The shallow element isolation film 5 includes a silicon oxide film inserted into its interior from the first surface 100A of the substrate. As an example, the shallow element isolation film 5 may include a silicon nitride film interposed between silicon oxide films.

[0024] The element isolation pattern 13 includes a conductive pattern 9 placed in the isolation trench DTR, an isolation insulating film 7 surrounding the sides of the conductive pattern 9, and an embedded insulating pattern 11 interposed between the conductive pattern 9 and the first surface 100A of the substrate 100. The conductive pattern 9 includes a conductive material, such as metal or polysilicon doped with impurities. The isolation insulating film 7 includes, for example, a silicon oxide film. The embedded insulating pattern 11 includes, for example, a silicon oxide film.

[0025] Although the diagram shows a boundary between the shallow element isolation film 5 and the element isolation pattern 13, there are cases where no boundary is observed between the shallow element isolation film 5 and the element isolation pattern 13. For example, there may be no interface between the shallow element isolation film 5 and the isolation insulating film 7. Also, the interface between the isolation insulating film 7 and the embedded insulating pattern 11 may not be observed.

[0026] A transmission gate TG is provided on the first surface 100A of the substrate 100 in each pixel region PX. As an example, a portion of the transmission gate TG is embedded inside the substrate 100. The transmission gate TG is of the vertical type. As an example, a first portion of the transmission gate TG is provided inside (in) the first surface 100A of the substrate 100, and a second portion is provided on (on) the first surface 100A of the substrate 100. That is, a portion of the transmission gate TG extends inside the substrate 100. The transmission gate TG is the gate electrode of a transmission transistor.

[0027] As another example, the transmission gate TG may be of a planar type, having a flat shape on the first surface 100A of the substrate 100.

[0028] A gate isolation pattern GI is interposed between the transmission gate TG and the substrate 100. A floating diffusion region (not shown) is provided within the substrate 100 adjacent to one side of the transmission gate TG. As an example, an impurity having a second conductivity type is doped into the floating diffusion region (not shown).

[0029] According to some embodiments of the present invention, light is incident on the substrate 100 through the second surface 100B of the substrate 100. Electron-hole pairs are generated at the PN junction by the incident light. The electrons thus generated move to the photoelectric conversion unit PD. The electrons move to a floating diffusion region (not shown) when a voltage is applied to the transmission gate TG.

[0030] An interlayer insulating film (ILD) is provided on the first surface 100A of the substrate 100, covering the first surface 100A. The interlayer insulating film (ILD) is a composite film comprising at least one film from among a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a porous low dielectric film, or a combination thereof. Wiring CLN is provided within the interlayer insulating film (ILD). Floating diffusion regions (not shown) are connected to the wiring CLN.

[0031] A fixed charge film 42 is provided on the second surface 100B of the substrate 100, covering the second surface 100B. The fixed charge film 42 is a single film or composite film comprising at least one film from among metal oxide films or metal fluoride films, or combinations thereof, each containing an amount of oxygen or fluorine that is less than the stoichiometric ratio. Therefore, the fixed charge film 42 has a negative fixed charge. As an example, the fixed charge film 42 includes a metal oxide film or metal fluoride film comprising at least one from among hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), titanium (Ti), yttrium (Y), lantanide, or combinations thereof. The fixed charge film 42 can improve dark current and white spots.

[0032] A protective film 41 is provided on a fixed charge film 42. The protective film 41 is a bottom antireflective coating (BARC) layer. The protective film 41 may be a single film or a multilayer film. The protective film 41 contains an insulating material having high transmittance. For example, the protective film 41 contains silicon oxide. For example, the protective film 41 may contain PEOx.

[0033] A back insulating film 26 is provided on the protective film 41. The back insulating film 26 covers the protective film 41. As an example, the back insulating film 26 contains aluminum oxide. As an example, the back insulating film 26 is a metal oxide film containing at least one of hafnium (Hf), zirconium (Zr), aluminum (Al), tantalum (Ta), titanium (Ti), yttrium (Y), lantanide, or a combination thereof.

[0034] A grid structure 71 is placed on the second surface 100B of the substrate 100. The grid structure 71 is superimposed on the element isolation pattern 13 and has a grid shape in a planar manner. The light-shielding pattern 48 contains, for example, titanium. The grid structure 71 has a refractive index smaller than that of the color filters CF1 and CF2 described later. The grid structure 71 can prevent crosstalk between adjacent pixel regions PX.

[0035] Color filters CF1 and CF2 are placed between adjacent grid structures 71. Each color filter CF1 and CF2 has one color from blue, green, and red. In other examples, color filters CF1 and CF2 may also include other colors such as cyan, magenta, or yellow. In the image sensor according to this example, color filters CF1 and CF2 are arranged in the form of a Bayer pattern. In other examples, color filters CF1 and CF2 may be arranged in the form of a 2x2 Tetra pattern, a 3x3 Nona pattern, or a 4x4 Hexadeca pattern.

[0036] A back protection layer 51 is placed on the color filters CF1 and CF2. The back protection layer 51 contains an insulating material.

[0037] The microlenses ML are positioned on the back protection layer 51. The edges of the microlenses ML are in contact with each other and connected to each other.

[0038] In addition to the photoelectric conversion unit PD and the transmission gate TG, the gate electrodes of a reset transistor (not shown), a source-follower transistor, and a selection transistor are provided on the first surface 100A of the substrate 100. The photoelectric conversion unit PD and the transistors constitute a unit pixel. In contrast, the gate electrodes of the reset transistor, the source-follower transistor, and the selection transistor may be provided on a separate additional substrate other than the substrate 100.

[0039] Referring again to Figures 4 and 5, the grid structure 71 is illustrated in more detail. The side walls and top surface of the grid structure 71 are in contact with the capping film 50. The side wall 713SW of the support member 713 and the outer wall 711OSW of the gap insulating film 711 are in contact with the capping film 50.

[0040] The fence gap 712 is defined as the portion enclosed by the gap insulating film 711. The fence gap 712 is defined as the open space enclosed by the gap insulating film 711. The fence gap 712 is, for example, an air gap. The lower surface 712BS of the fence gap 712 is in contact with the gap insulating film 711. The level of the lower surface 712BS of the fence gap 712 is higher than the level of the lowest surface 50BMS of the capping film 50.

[0041] The lower surface 711BS of the gap insulating film 711 is in contact with the back insulating film 26. The lower surface 711BS of the gap insulating film 711 is substantially at the same level as the lowest surface 50BMS of the capping film 50.

[0042] The uppermost point of the gap 712TP, defined at the top of the fence gap 712, is located at the level between the top surface of the support member and the uppermost point 712WTP of the side wall 712SW of the fence gap 712.

[0043] The fence gap 712 is in contact with the gap insulating film 711 and includes a curved upper gap surface 712CTS. The fence gap 712 has a flat surface and side walls 712SW1 and 712SW2 of the fence gap 712 that extend in a second direction D2. The side walls 712SW1 and 712SW2 of the fence gap 712 extend from the upper gap surface 712CTS toward the semiconductor substrate 100. The fence gap 712 has a first side wall 712SW1 in contact with the gap insulating film 711 and a second side wall 712SW2 opposite the first side wall 712SW1. The fence gap 712 is in contact with the gap insulating film 711 and has a flat surface and a lower surface 712BS of the fence gap 712 that extends in a third direction D3. The lower surface 712BS of the fence gap 712 includes a flat surface between the first side wall 712SW1 and the second side wall 712SW2.

[0044] The gap insulating film 711 covers the upper curved surface 712CTS, the first side wall 712SW1, and the second side wall 712SW2 of the fence gap 712. The gap insulating film 711 completely covers the upper curved surface 712CTS, the first side wall 712SW1, and the second side wall 712SW2 of the fence gap 712. The gap insulating film 711 covers the lower surface 712BS of the fence gap 712. For example, the gap insulating film 711 covers 50% or more of the lower surface 712BS of the fence gap 712. For example, the gap insulating film 711 covers 80% or more of the lower surface 712BS of the fence gap 712. For example, the gap insulating film 711 may completely cover the lower surface 712BS of the fence gap 712.

[0045] The upper part of the fence gap 712 and the lower surface of the gap insulating film 711 facing it are curved. The upper curved surface 712CTS of the gap has a shape that protrudes toward the fence gap 712. The uppermost point of the fence gap 712 is defined as the uppermost point of the gap 712TP. The level of the uppermost point of the gap 712TP is higher than the level of the uppermost point 712WTP of the side wall 712SW of the fence gap 712.

[0046] The upper curved surface 712CTS of the gap extends from the top of the gap 712TP to the top of the side wall 712WTP of the fence gap. The side wall 712SW of the fence gap 712 is coplane with the gap insulating film 711.

[0047] The lower surface 713CB of the support member 713 includes a curved surface. The support member 713 has a fan-shaped form, for example, that faces the fence gap 712. The upper surface of the gap insulating film 711 that is in contact with the support member 713 is a curved gap insulating film curved surface 711CTS, and is defined as the lower surface 713CB of the support member 713 that is in contact with the gap insulating film 711.

[0048] The gap insulating film 711 contains a metal oxide. The gap insulating film 711 contains one or more of the following: Al2O3, SiO2, TiO2, Ta2O5, Ta2O3, HfO, ZrO, Si3N4, or SiCN.

[0049] The support member 713 includes a silicon oxide film or a silicon nitride film. The support member 713 includes Si3N4, SiCN, SiOCN, SiBN, and SiBCN.

[0050] Referring again to Figure 4, the grid structure 71IR of the intervening region is illustrated in more detail. The support member 713 of the grid structure 71IR of the intervening region is integral. The gap insulating film 711 of the grid structure 71IR includes the uppermost point 711TP of the gap insulating film, which is defined as the uppermost point of the gap insulating film 711. The surface extending from the uppermost point 711TP of the gap insulating film to the outer wall 711OSW of the gap insulating film 711 is defined as the gap insulating film surface 711CTS. The gap insulating film surface 711CTS is coplane with the lower surface 713CB of the support member 713.

[0051] Referring again to Figure 5, the grid structure 71CR in the intersecting region is illustrated in more detail. The support members 713 of the grid structure 71CR in the intersecting region are separated by the gap insulating film 711. The gap insulating film 711 is interposed between adjacent, separated grid structures 71CR in the intersecting region, and the uppermost surface 711TMS of the gap insulating film 711 is in contact with the capping film 50.

[0052] As described above, the grid structure 71 includes a fence gap 712 inside. Through this, crosstalk between color filters CF can be suppressed, and a constant fence gap 712 can be formed.

[0053] Figures 6, 16, and 18 show an image sensor according to some embodiments, and are cross-sectional views corresponding to an enlarged cross-sectional view of M in Figure 2. Figures 7, 17, and 19 show an image sensor according to some embodiments, and are cross-sectional views corresponding to an enlarged cross-sectional view of N in Figure 3.

[0054] Figures 8, 10, 12, and 14 show image sensors according to some embodiments and are cross-sectional views corresponding to the enlarged cross-sectional view of X in Figure 2. Figures 9, 11, 13, and 15 show image sensors according to some embodiments and are cross-sectional views corresponding to the enlarged cross-sectional view of Y in Figure 3.

[0055] For the sake of simplicity, explanations that overlap with Figures 1 to 5 will be omitted.

[0056] Referring to Figures 6 and 7, a shielding film 60 is provided beneath the capping film 50. The shielding film 60 surrounds the top and sides of the grid structure 71. The shielding film 60 covers the back insulating film 26. The capping film 50 covers the top surface of the shielding film 60. The shielding film 60 contains silicon oxide. The shielding film 60 contains a different material from the capping film 50.

[0057] The outer wall 711OSW of the gap insulating film 711 and the side wall 713SW of the support member 713 are in contact with the shield film 60. The upper surface of the support member 713 is in contact with the shield film 60. The level of the lower surface 712BS of the fence gap 712 is higher than the level of the lowest surface 60BMS of the shield film 60. The level of the lower surface 711BS of the gap insulating film 711 is substantially the same as the level of the lowest surface 60BMS of the shield film 60. The level of the lowest surface 60BMS of the shield film 60 is lower than the level of the lower surface of the capping film 50.

[0058] In the intervening grid structure 71IR, the shield film 60 is in contact with the upper and side surfaces of the support member 713, and is separated from the upper surface of the gap insulating film 711.

[0059] In the grid structure 71CR of the intersection region, the shield film 60 is in contact with the upper surface and side surface of the support member 713 and with the uppermost surface 711TMS of the gap insulating film 711.

[0060] Referring to Figures 8 and 9, the grid structure 71 penetrates the back insulating film 26 and the protective film 41. The grid structure 71 is in contact with the stationary charge film 42.

[0061] The level of the lower surface 712BS of the fence gap 712 is lower than the level of the lowest surface 50BMS of the capping film 50. The outer wall 711OSW of the gap insulating film 711 is in contact with the capping film 50, the back insulating film 26, and the protective film 41.

[0062] Referring to Figures 10 and 11, the grid structure 71 penetrates the back insulating film 26 and the protective film 41. A shielding film 60 is provided below the capping film 50. The grid structure 71 is in contact with the stationary charge film 42. The level of the bottom surface 712BS of the fence gap 712 is lower than the level of the bottom surface 50BMS of the capping film 50. The level of the bottom surface 712BS of the fence gap 712 is lower than the level of the bottom surface 60BMS of the shielding film 60. The outer wall 711OSW of the gap insulating film 711 is in contact with the shielding film 60, the back insulating film 26, and the protective film 41. The level of the bottom surface 711BS of the gap insulating film 711 is lower than the level of the bottom surface 60BMS of the shielding film 60.

[0063] Referring to Figures 12 and 13, a conductive member MG is further provided below the grid structure 71. The conductive member MG is interposed between the substrate 100 and the gap insulating film 711. The conductive member MG is in contact with the fixed charge film 42. The conductive member MG is interposed between the fixed charge film 42 and the gap insulating film 711. The width of the conductive member MG is similar to, but not limited to, that of the grid structure 71. The side walls of the conductive member MG are in contact with the back insulating film 26 and the protective film 41. The upper surface of the conductive member MG is in contact with the gap insulating film 711. The conductive member MG includes, for example, TiN, W, or Al.

[0064] Referring to Figures 14 and 15, a conductive member MG is further provided beneath the grid structure 71. The conductive member MG is interposed between the substrate 100 and the gap insulating film 711. The conductive member MG is in contact with the fixed charge film 42. The conductive member MG is interposed between the fixed charge film 42 and the gap insulating film 711. A shielding film 60 is provided beneath the capping film 50. The shielding film 60 and the conductive member MG are separated.

[0065] Referring to Figures 16 and 17, the grid structure 71 further includes conductive lines 714 that surround and contact the gap insulating film 711. The outer wall 714OSW of the conductive line 714 is in contact with the capping film 50, and the upper surface 714CTS of the conductive line 714 is in contact with the support member 713. The gap insulating film 711 is separated from the support member 713 and the capping film 50 by the conductive line 714. The gap insulating film 711 is separated from the back insulating film 26 by the conductive line 714.

[0066] In the intervening grid structure 71IR, the upper surface of the conductive line 714 is in contact with the support member 713, and in the intersecting grid structure 71CR, the upper surface of the conductive line 714 is in contact with both the support member 713 and the capping film 50.

[0067] Contrary to what is shown in the illustration, the uppermost surface of the gap insulating film 711 can also be in contact with the capping film 50. In this case, the capping film 50 is in contact with the support member 713, the uppermost surface of the gap insulating film 711, and the upper surface of the conductive line 714.

[0068] Referring to Figures 18 and 19, the grid structure 71 further includes conductive lines 714 that surround and contact the gap insulating film 711. A shielding film 60 is provided beneath the capping film 50. The capping film 50 is separated from the grid structure 71 by the shielding film 60.

[0069] The outer wall 714OSW of the conductive line 714 is in contact with the shield film 60, and the upper surface 714CTS of the conductive line 714 is in contact with the support member 713. The lower surface of the conductive line 714 is in contact with the back insulating film 26. The gap insulating film 711 is separated from the support member 713 and the capping film 50 by the conductive line 714. The gap insulating film 711 is separated from the back insulating film 26 by the conductive line 714. The shield film 60 is in contact with the support member, the conductive line 714, and the gap insulating film 711.

[0070] Figures 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, and 52 are diagrams illustrating a method for manufacturing an image sensor according to some embodiments of the present invention, and are enlarged views corresponding to an enlarged view of Q in Figure 2.

[0071] Figures 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, and 53 are diagrams illustrating a method for manufacturing an image sensor according to some embodiments of the present invention, and are enlarged views corresponding to an enlarged view of R in Figure 3.

[0072] Referring to Figures 20 to 31, the manufacturing method of the image sensor according to the embodiments shown in Figures 2 to 5 is illustrated.

[0073] Referring to Figures 20 and 21, a fixed charge film 42, a protective film 41, and a back insulating film 26 are prepared on a substrate 100 and an element isolation pattern 13 having the structure described with reference to Figures 2 to 5. A patterning film 801 is formed on the back insulating film 26. The patterning film 801 contains SOC, SOH, PR, or SiO2.

[0074] Referring to Figures 22 and 23, the patterned film 801 is patterned in the areas where the grid structure will subsequently be formed, creating the first trench TR1 and the second trench TR2. The first trench TR1 is formed in the area where the intervening grid structure 71IR will be formed, and the second trench TR2 is formed in the area where the crossing grid structure 71CR will be formed.

[0075] Referring to Figures 24 and 25, the preliminary support film p713 is formed. The preliminary support film p713 is formed on the patterning film 801.

[0076] Referring to Figure 24, in the area where the intervening grid structure 71IR is formed, the preliminary support film p713 is formed so as to cover the upper surface of the first trench TR1. Therefore, the upper surface p713UC and the lower surface p713LC of the curved preliminary support film p713 are separated. The preliminary support film p713 fills a portion of the first trench TR1, and the unfilled portion is defined as the first void V1.

[0077] Referring to Figure 25, in the area where the grid structure 71CR in the intersection region is formed, the preliminary support membrane p713 is formed so as not to block the upper surface of the second trench TR2. In this case, a first space SPA1 with an open top is formed by filling a part of the second trench TR2 with the preliminary support membrane p713. The exposed curved surface p713UC of the preliminary support membrane p713 forms an inseparable whole.

[0078] Referring to Figures 26 and 27, a preliminary gap insulating film 711L is coated onto the preliminary support film p713. The preliminary gap insulating film 711L is formed through a first space SPA1, which is open at the top in the area where the grid structure 71CR in the cross region is formed. As an example, the preliminary gap insulating film 711L is formed in a low-temperature process (process temperature 80-375°C) using an Atomic Layer Deposition (ALD) process method that has good step coverage.

[0079] As a result of the formation of the preliminary gap insulating film 711L, a second void V2 is formed in the portion where the intervening grid structure 71IR is formed, and a third void V3 is formed in the portion where the crossing grid structure 71CR is formed.

[0080] Referring to Figures 28 and 29, a portion of the preliminary support film p713 and the preliminary gap insulating film 711L are removed. Through this, the support member 713 and the gap insulating film 711 are formed.

[0081] Through this, the upper surface of the patterning film 801 and the upper surface of the support member 713 are exposed in the area where the grid structure 71IR of the intervening region is formed. The upper surface of the patterning film 801, the upper surface of the support member 713, and the upper surface of the gap insulating film 711 are exposed in the area where the grid structure 71CR of the intersecting region is formed.

[0082] Referring to Figures 30 and 31, the patterning film 801 is removed. After the patterning film 801 is removed, the capping film 50 is formed on the back insulating film 26. The capping film 50 is formed to cover the exposed back insulating film 26, the side walls of the gap insulating film 711, and the side walls and top surface of the support member 713. The second void V2 and the third void V3 form the fence gap 712.

[0083] Subsequently, a color filter CF is placed on the capping film 50, and a back protection layer 51 and microlenses are formed on the back protection layer 51. The image sensors shown in Figures 1 to 5 are then formed.

[0084] Referring to Figures 32 to 35, the manufacturing method of the image sensor according to the embodiments shown in Figures 6 to 7 is illustrated. The steps up to Figure 29, prior to the steps in Figures 30 and 31, are carried out in the same manner as described above.

[0085] Referring to Figures 32 and 33, the upper surface of the patterned film 801 and the upper surface of the support member 713 are exposed in the area where the intervening grid structure 71IR is formed. In the area where the intersecting grid structure 71CR is formed, the upper surface of the patterned film 801, the upper surface of the support member 713, and the upper surface of the gap insulating film 711 are exposed. Subsequently, the patterned film 801 is removed. After the patterned film 801 is removed, the shield film 60 is formed on the back insulating film 26. The shield film 60 is formed to cover the exposed back insulating film 26, the side walls of the gap insulating film 711, and the side walls and upper surface of the support member 713. The second void V2 and the third void V3 form the fence gap 712.

[0086] Referring to Figures 34 and 35, a capping film 50 is formed on the shield film 60. The capping film 50 is formed to completely cover the shield film 60. A color filter CF is provided on the shield film 60, and a back protection layer 51 and microlenses are formed on the back protection layer 51. The image sensor shown in Figures 6 and 7 is formed.

[0087] Referring to Figures 36 to 39, the manufacturing method of the image sensor according to the embodiments shown in Figures 8 to 11 is illustrated.

[0088] Referring to Figures 36 and 37, a fixed charge film 42, a protective film 41, and a back insulating film 26 are prepared on the substrate 100 and the element isolation pattern 13. A patterning film 801 is formed on the back insulating film 26. An additional mask film AM is formed on the patterning film 801.

[0089] Referring to Figures 38 and 39, the patterning film 801 and the additional mask film AM are patterned. The patterning film 801 and the additional mask film AM form the first extension trench TR12 and the second extension trench TR22. The first extension trench TR12 and the second extension trench TR22 are formed by the sidewalls of the exposed patterning film 801, the sidewalls of the back insulating film 26, the sidewalls of the protective film 41, and the upper surface of the fixed charge film 42. The first extension trench TR12 is formed in the area where the intervening grid structure 71IR is formed, and the second extension trench TR22 is formed in the area where the crossing grid structure 71CR is formed.

[0090] Subsequently, the image sensors shown in Figures 8 to 11 are formed using a method similar to that described in Figures 24 to 35.

[0091] Referring to Figures 40 to 47, the manufacturing method of the image sensor according to the embodiments shown in Figures 8 to 15 is illustrated.

[0092] Referring to Figures 40 and 41, a fixed charge film 42, a protective film 41, and a back insulating film 26 are prepared on the substrate 100 and the element isolation pattern 13. A pattern mask film 802 is formed on the back insulating film 26. The protective film 41 and the back insulating film 26 are etched by the pattern mask film 802. Through this, a first hole H1 and a second hole H2 are formed. The first hole H1 and the second hole H2 are defined by the exposed sidewall of the protective film 41, the sidewall of the back insulating film 26, and the upper surface of the fixed charge film 42.

[0093] Referring to Figures 42 and 43, the conductive member MG is formed to fill the first hole H1 and the second hole H2, and then the pattern mask film 802 and a portion of the upper part of the conductive member MG are removed. Through this, the back insulating film 26 is exposed. The conductive member MG is left to the same level as the exposed back insulating film 26.

[0094] Referring to Figures 44 and 45, a patterned film 801 is formed on the back insulating film 26 and the conductive member MG. The patterned film 801 is formed to cover the upper surface of the conductive member MG and the upper surface of the back insulating film 26.

[0095] Referring to Figures 46 and 47, a first trench TR1 is formed in the area where the patterning film 801 is patterned and the intervening grid structure 71IR is formed, and a second trench TR2 is formed in the area where the crossing grid structure 71CR is formed. Subsequently, the image sensors shown in Figures 8 to 15 are formed in the same manner as in Figures 38 to 46.

[0096] Referring to Figures 48 to 53, the manufacturing method of the image sensor according to the embodiments shown in Figures 16 to 19 is illustrated.

[0097] Referring to Figures 48 and 49, the steps from Figure 2 to Figure 25 proceed in the same manner as described above.

[0098] A preliminary conductive line 714L is applied to the preliminary support film p713. The preliminary conductive line 714L is formed through a space that is open at the top in the area where the grid structure 71CR in the cross region is formed.

[0099] The formation of the preliminary conductive line 714L creates a first empty space VC1 surrounded by the preliminary conductive line 714L in the area where the intervening grid structure 71IR is formed, and a second empty space VC2 is formed by the preliminary conductive line 714L in the area where the crossing grid structure 71CR is formed.

[0100] Referring to Figures 50 and 51, a preliminary gap insulating film 711L is formed on the preliminary conductive line 714L. By forming the preliminary gap insulating film 711L in the portion where the grid structure 71CR of the intersection region is formed, it is closed without any open space.

[0101] The preliminary gap insulating film 711L is formed through an open space at the top in the area where the grid structure 71CR in the cross region is formed.

[0102] In the area where the intervening grid structure 71IR is formed, a third empty space VC3 surrounded by a preliminary gap insulating film 711L is formed.

[0103] In the area where the grid structure 71CR of the intersection region is formed, a fourth empty space VC4 surrounded by a preliminary gap insulating film 711L is formed.

[0104] Referring to Figures 52 and 53, a portion of the preliminary support film p713, preliminary conductive line 714L, and preliminary gap insulating film 711L is removed. Through this, the support member 713 is formed. The third empty space VC3 and the fourth empty space VC4 form a fence gap 712. Subsequently, an image sensor according to the embodiments shown in Figures 16 to 19 is formed through a process similar to that described above.

[0105] The above description of embodiments of the present invention provides illustrative examples for explaining the present invention. Therefore, it is clear that the present invention is not limited to the above embodiments, and that various modifications and changes are possible, such as combining embodiments and implementing them by persons with ordinary skill in the art within the technical concept of the present invention. [Explanation of symbols]

[0106] 5. Shallow element isolation membrane 7 Separation insulating film 9 Conductive Patterns 11 Embedded insulation pattern 13-element isolation pattern 26 Back insulating film 41 Protective film 42 Fixed charge membrane 50 Capping film 51. Back protection layer 60 Shielding film 71 Grid Structure Grid structure of the 71IR intervening region 71CR Intersection Grid Structure 100 circuit boards 711 Gap Insulator 712 Fence Gap 713 Support member 714 Conductive Line CF Color Filter CLN wiring DTR Separation Trench ILD (Interlayer Diode) ML Microlens PD Photoelectric Conversion Unit PX Pixel area STR shallow element isolation trench TG transmission gate

Claims

1. A semiconductor substrate in which multiple photoelectric conversion units are defined, Multiple color filters on the semiconductor substrate, A grid structure is placed between adjacent color filters, The aforementioned grid structure is The fence gap defined by the gap insulating film, A gap insulating film surrounding the fence gap, The gap insulating film includes a support member disposed on the gap insulating film, The aforementioned fence gap is The upper curved surface of the gap having a curved surface, A first side wall extending from the upper curved surface of the gap toward the semiconductor substrate, A second side wall opposite to the first side wall, A lower surface including a flat surface between the first side wall and the second side wall, The gap insulating film completely covers the upper curved surface of the gap, the first side wall, and the second side wall of the fence gap. The gap insulating film covers 50% or more of the lower surface of the fence gap. The image sensor is characterized in that the support member is spaced apart from the fence gap.

2. The image sensor according to claim 1, characterized in that the upper surface of the gap insulating film in contact with the support member includes a curved gap insulating film surface.

3. The uppermost point of the aforementioned fence gap is defined as the uppermost point of the gap. The level of the highest point of the gap is higher than the level of the highest point of the side wall of the fence gap. The image sensor according to claim 2, characterized in that the upper curved surface of the gap extends from the uppermost point of the gap to the uppermost point of the side wall of the fence gap.

4. The grid structure further includes a capping film surrounding the top and side surfaces, The side wall of the support member and the side wall of the gap insulating film are in contact with the capping film. The image sensor according to claim 1, characterized in that the capping film and the fence gap are separated.

5. The image sensor according to claim 1, characterized in that the level of the lower surface of the fence gap is lower than the level of the lowest surface of the capping film.

6. The image sensor according to claim 1, characterized in that the gap insulating film covers 80% or more of the lower surface of the fence gap.

7. A shielding film surrounding the top and side surfaces of the grid structure, The shield film further includes a capping film on the shield film, The image sensor according to claim 1, characterized in that the level of the lower surface of the fence gap is lower than the level of the lowest surface of the shield film.

8. The image sensor according to claim 1, characterized in that the gap insulating film completely covers the lower surface of the fence gap.

9. A fixed charge film on the semiconductor substrate, The protective film on the fixed charge film, A back insulating film on a protective film, and The image sensor according to claim 1, characterized in that the outer wall of the gap insulating film is in contact with the protective film and the back insulating film.

10. A semiconductor substrate in which multiple photoelectric conversion units are defined, Multiple color filters on the semiconductor substrate, A grid structure is placed between adjacent color filters, The grid structure includes a grid structure in the intervening region and a grid structure in the intersection region. The aforementioned grid structure is The fence gap defined by the gap insulating film, A gap insulating film surrounding the fence gap, The gap insulating film includes a support member disposed on the gap insulating film, The aforementioned fence gap is The upper curved surface of the gap having a curved surface, A first side wall extending from the upper curved surface of the gap toward the semiconductor substrate, A second side wall opposite to the first side wall, A lower surface including a flat surface between the first side wall and the second side wall, The gap insulating film completely covers the upper curved surface of the gap, the first side wall, and the second side wall of the fence gap. The gap insulating film covers 50% or more of the lower surface of the fence gap. The image sensor is characterized in that the grid structure in the intersection region is separated by a gap insulating film.

Images