Microlens assembly, photoelectric conversion device and manufacturing method, and imaging system

Abstract

The present disclosure provides a microlens assembly, a photoelectric conversion device and a manufacturing method and an imaging system, and relates to the technical field of semiconductors. The microlens assembly comprises a first microlens array and a first light-transmitting piece. The first light-transmitting piece is arranged on the first microlens array, and the refractive index of the first light-transmitting piece is greater than the refractive index of an ambient medium. The present disclosure changes the wavelength of incident light by arranging the first light-transmitting piece with a high refractive index on the first microlens array, so that the light with a shorter wavelength forms an object image with a smaller diameter after being imaged by the first microlens array, thereby improving the resolution of the imaging system.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor technology, and in particular to a microlens assembly, a photoelectric conversion device and a manufacturing method, and an imaging system. BACKGROUND

[0002] An image sensor is a photoelectric conversion device that converts a light image on a photosensitive surface into an electric signal in a corresponding proportional relationship, and is widely used in electronic products. Common image sensors include CMOS image sensors (CIS) and charge-coupled device (CCD).

[0003] A CIS image sensor generally includes a photosensitive element, a microlens array, and a peripheral circuit. The microlens array is disposed on the photosensitive element, and the peripheral circuit is connected to the photosensitive element. When external light passes through the microlens array and enters the photosensitive element, the photosensitive element can convert the light signal into an electric signal, and the electric signal is output as an image through the peripheral circuit. SUMMARY

[0004] In view of the above problems, the present disclosure provides a microlens assembly, a photoelectric conversion device and a manufacturing method, and an imaging system, which can improve the resolution of the imaging system.

[0005] To achieve the above-mentioned purpose, the present disclosure provides the following technical solutions:

[0006] A first aspect of the present disclosure provides a microlens assembly, comprising:

[0007] a first microlens array;

[0008] a first light-transmitting piece disposed on the first microlens array, the first light-transmitting piece being configured to transmit light propagating in an ambient medium into the first microlens array, wherein a refractive index of the first light-transmitting piece is greater than a refractive index of the ambient medium.

[0009] In some embodiments, the refractive index of the first light-transmitting piece is greater than the refractive index of the first microlens array.

[0010] In some embodiments, the microlens assembly further comprises a second light-transmitting piece disposed between the first light-transmitting piece and the first microlens array, and a refractive index of the second light-transmitting piece is less than the refractive index of the first light-transmitting piece and the first microlens array.

[0011] In some embodiments, the first microlens array comprises a microlens array or a microlens array.

[0012] In some embodiments, the first microlens array includes a plurality of first microlenses, the first light-transmitting piece includes a plurality of first light-transmitting portions, and each of the first light-transmitting portions corresponds to one or more of the first microlenses; wherein the first microlens includes a convex lens or a concave lens.

[0013] In some embodiments, each of the first light-transmitting portions includes a second microlens, and a plurality of the second microlenses form a second microlens array, wherein each of the second microlenses corresponds to one or more of the first microlenses.

[0014] In some embodiments, the second microlens has a second focal point, and the second focal point is formed in the second light-transmitting piece.

[0015] In some embodiments, the second light-transmitting piece has a first thickness, and a maximum distance from the second focal point to a top surface of the second light-transmitting piece is not greater than one half of the first thickness.

[0016] In some embodiments, the first microlens has a first curvature, and the second microlens has a second curvature, wherein the second curvature is different from the first curvature.

[0017] A second aspect of the embodiments of the present disclosure provides a photoelectric conversion device, including a photosensitive element layer and the microlens assembly described in the above embodiments.

[0018] The microlens assembly is disposed on the photosensitive element layer.

[0019] In some embodiments, the photosensitive element layer includes a filter layer, and the filter layer includes a plurality of filter regions, wherein each of the filter regions corresponds to one or more of the first microlenses.

[0020] In some embodiments, the photosensitive element layer further includes a photosensitive element layer, and the photosensitive element layer includes a plurality of photosensitive elements, wherein each of the photosensitive elements corresponds to one or more of the first microlenses.

[0021] In some embodiments, the first microlens has a first focal point, and the first focal point is formed in the photosensitive element layer, wherein the photosensitive element layer has a second thickness, and a maximum distance from the first focal point to a bottom surface of the first microlens is not less than one half of the second thickness.

[0022] In some embodiments, an anti-reflection layer is further included, and the anti-reflection layer is disposed between the microlens assembly and the photosensitive element layer.

[0023] A third aspect of the embodiments of the present disclosure provides an imaging system, including the photoelectric conversion device described in the above embodiments.

[0024] and a signal processing unit that processes a signal output from the photoelectric conversion device.

[0025] A fourth aspect of the embodiments of the present disclosure provides a method for manufacturing a photoelectric conversion device, comprising: providing a substrate, forming a photosensitive element layer in the substrate;

[0026] forming a first microlens array on the photosensitive element layer, the first microlens array forming a first light receiving surface;

[0027] forming a first light-transmitting member covering the first light receiving surface on the first microlens array, a top surface of the first light-transmitting member constituting a second light receiving surface, light propagating in an ambient medium being transmitted to the first light receiving surface through the second light receiving surface, wherein a refractive index of the first light-transmitting member is greater than a refractive index of the ambient medium.

[0028] In some embodiments, the step of forming a first microlens array on the photosensitive element layer comprises:

[0029] depositing a first lens material layer on the substrate on which the photosensitive element layer is formed;

[0030] forming the first lens material layer according to an optical design pattern, forming a plurality of first microlenses arranged in connection with or at intervals from each other.

[0031] In some embodiments, after the step of forming a first microlens array on the photosensitive element layer, before the step of forming a first light-transmitting member covering the first light receiving surface on the first microlens array, the method further comprises:

[0032] forming a light-transmitting material layer on the first microlens array, a refractive index of the light-transmitting material layer being less than a refractive index of the first microlens array;

[0033] removing part of the thickness of the light-transmitting material layer, forming a second light-transmitting member, the second light-transmitting member at least filling a region between adjacent first microlenses, and the second light-transmitting member having a flat top surface, wherein a refractive index of the second light-transmitting member is less than a refractive index of the first light-transmitting member and a refractive index of the first microlens array.

[0034] In some embodiments, the step of forming a first light-transmitting member covering the first light receiving surface on the first microlens array comprises:

[0035] forming a second lens material layer covering the second light-transmitting member, a refractive index of the second lens material layer being greater than a refractive index of the first microlens array and a refractive index of the first light-transmitting member;

[0036] forming the second lens material layer according to an optical design pattern, forming a first light-transmitting member.

[0037] In some embodiments, the step of forming the second lens material layer according to the optical design pattern comprises:

[0038] The second lens material layer is patterned to form a plurality of second light-transmitting parts arranged in connection with or at intervals from each other, each of the second light-transmitting parts comprising a second microlens, and a plurality of the second microlenses form a second microlens array, one of the second microlenses corresponding to one or more of the first microlenses.

[0039] In the microlens assembly, the photoelectric conversion device and the manufacturing method and the imaging system provided by the embodiments of the present disclosure, by arranging the first light-transmitting part on the first microlens array, and the refractive index of the first light-transmitting part is greater than the refractive index of the ambient medium, so arranged, the wavelength of the light propagating in the ambient medium and transmitted into the first light-transmitting part can be shortened, so that the light with shorter wavelength forms an object image with smaller diameter after imaging by the first microlens array, thereby improving the resolution of the imaging system.

[0040] In addition to the technical problems solved by the embodiments of the present disclosure described above, the technical features constituting the technical solutions and the beneficial effects brought by these technical features, the other technical problems solved by the microlens assembly, the photoelectric conversion device and the manufacturing method and the imaging system provided by the embodiments of the present disclosure, the other technical features included in the technical solutions and the beneficial effects brought by these technical features will be further described in detail in the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present disclosure, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0042] Figure 1 A structural schematic diagram of the microlens array provided in the related art;

[0043] Figures 2 to 13 A structural schematic diagram of the microlens assembly provided by the embodiments of the present disclosure;

[0044] Figures 14 to 22 A structural schematic diagram of the photoelectric conversion device provided by the embodiments of the present disclosure;

[0045] Figure 23 A structural schematic diagram of the light-sensing element layer provided by the embodiments of the present disclosure;

[0046] Figure 24A structural schematic diagram of an imaging system provided by an embodiment of the present disclosure;

[0047] Figure 25 A process flow chart of a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0048] Figure 26 A structural schematic diagram of forming a photosensitive element layer in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0049] Figure 27 A structural schematic diagram of forming a first lens material layer in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0050] Figure 28 A structural schematic diagram of forming a photoresist layer in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0051] Figure 29 A structural schematic diagram of forming a first microlens array in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0052] Figure 30 A structural schematic diagram of forming a light-transmitting material layer in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure;

[0053] Figure 31 A structural schematic diagram of forming a second light-transmitting member in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure Figure 1 ;

[0054] Figure 32 A structural schematic diagram of forming a second light-transmitting member in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure Figure 2 ;

[0055] Figure 33 A structural schematic diagram of forming a second lens material in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure Figure 1 ;

[0056] Figure 34 A structural schematic diagram of forming a second lens material in a method for manufacturing a photoelectric conversion device provided by an embodiment of the present disclosure Figure 2 .

[0057] Reference signs:

[0058] 10: microlens array; 11: microlens;

[0059] 100: microlens assembly;

[0060] 110: first microlens array; 111: first microlens; 112: first light-receiving surface;

[0061] 120: First light-transmitting element; 121: First light-transmitting section; 122: Second light-receiving surface;

[0062] 130: Second light-transmitting element;

[0063] 140: First lens material layer;

[0064] 150: Photoresist layer;

[0065] 160: Translucent material layer;

[0066] 170: Second lens material layer;

[0067] 200: Photosensitive element layer;

[0068] 210: Photosensitive element layer; 211: Photosensitive element; 212: Isolation structure; 220: Interconnect layer; 221: Interconnect structure; 230: Filter layer; 231: Filter area; 240: Anti-reflection layer. Detailed Implementation

[0069] like Figure 1 As shown in the related technology, the microlens array 10 typically includes multiple microlenses 11. Each microlens 11 is used to converge the light entering the microlens 11 to enhance the amount of light that the photosensitive element corresponding to the microlens can receive. However, as imaging systems develop towards integration and miniaturization, the size of the microlenses 11 becomes smaller and smaller. According to the imaging principle of light, the smaller the size of the microlens 11, the larger the diameter of the formed image, which in turn reduces the resolution of the imaging system with the microlens array.

[0070] To address the aforementioned technical problems, in this embodiment of the present disclosure, by setting a first light-transmitting element on the first microlens array, and the refractive index of the first light-transmitting element being greater than the refractive index of the ambient medium, the wavelength of the light transmitted from the ambient medium to the first light-transmitting element can be shortened, so that the light with a shorter wavelength forms an image with a smaller diameter after being imaged by the first microlens array, thereby improving the resolution of the imaging system.

[0071] To make the above-mentioned objects, features, and advantages of the embodiments of this disclosure more apparent and understandable, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0072] Example 1

[0073] As shown in Figures 2 to 13 The microlens assembly 100 provided by the embodiment of the present disclosure can be applied to photoelectric conversion devices, such as image sensors.

[0074] The microlens assembly 100 includes a first microlens array 110, which is arranged on a photosensitive element layer in a photoelectric conversion device to guide incident light into the photosensitive element layer.

[0075] In the embodiment, the first microlens array 110 includes a microlens array or a microconcave lens array, which can have a structure as shown in Figure 2 and Figure 3

[0076] The first microlens array 110 includes a plurality of first microlenses 111, which are located on the same layer and can be closely arranged along a first direction, and the structure can be as shown in Figure 2 and Figure 3 The plurality of first microlenses 111 can be arranged at intervals along the first direction, and the structure can be as shown in Figure 4 and Figure 5 wherein the distance between adjacent first microlenses 111 can be equal or unequal, and can be freely set according to the situation. In addition, the first direction can be understood as the X direction in Figure 2 .

[0077] The first light-transmitting member 120 is arranged on the first microlens array 110 to transmit light propagating in an environment medium into the first microlens array 110, wherein the refractive index of the first light-transmitting member 120 is greater than the refractive index of the environment medium.

[0078] In the embodiment, if the incident light propagates directly from air to the first light-transmitting member 120, the propagation medium is air, and accordingly, the refractive index of the first light-transmitting member 120 is greater than the refractive index of air; for example, if the incident light propagates from air to other propagation medium, and then propagates from the other propagation medium into the first light-transmitting member 120, the refractive index of the first light-transmitting member 120 is greater than the refractive index of the other propagation medium.

[0079] The calculation formula of the diameter of the object image formed after the incident light passes through the first microlens array 110 is as follows: wherein λ is the wavelength of the incident light, f is the focal length of the first microlens, and d is the diameter of the first microlens.

[0080] From the above formula, it can be seen that the smaller the wavelength of the incident light, the smaller the diameter of the object image after imaging by the first microlens array 110, thereby improving the resolution of the imaging system.

[0081] ​Based on the above theory, the first light-transmitting piece 120 is arranged on the first microlens array 110. The refractive index of the first light-transmitting piece 120 is greater than that of the ambient medium. According to the relationship between the refractive index and the wavelength, the greater the refractive index, the smaller the wavelength. Therefore, after the light from the ambient medium passes through the first light-transmitting piece 120, the light is converted into light with a shorter wavelength after propagating through the first light-transmitting piece 120. Thus, the light with a shorter wavelength forms an object image with a smaller diameter after imaging through the first microlens array 110, thereby improving the resolution of the imaging system.

[0082] In addition, it should be noted that when the incident light passes through the first light-transmitting piece 120 into the first microlens array 110, not only can the wavelength of the incident light be shortened, but also the refractive angle of the incident light can be reduced to reduce the interference between the adjacent two first microlenses 111.

[0083] For example, continuing to refer to the first light-transmitting piece 120, the first microlens array 110, the first microlens 111, the second microlens 112, the third microlens 113, the fourth microlens 114, the fifth microlens 115, the sixth microlens 116, the seventh microlens 117, the eighth microlens 118, the ninth microlens 119, and the tenth microlens 120 shown in FIGS. 1 to 3, it is assumed that the light propagates from the air to the first light-transmitting piece 120, and the light from the air into the first light-transmitting piece 120 is referred to as incident light, which has a first incident angle r1, and the incident light has a large angle, such as the light propagating along the tangent direction of the right edge of the second first microlens 111; the light after refraction through the first light-transmitting piece 120 is referred to as first refracted light, which has a first refractive angle r2; and the light after refraction through the first microlens 111 is referred to as second refracted light, which has a second refractive angle r3. Figure 2 Figure 3 For example, continuing to refer to the first light-transmitting piece 120, the first microlens array 110, the first microlens 111, the second microlens 112, the third microlens 113, the fourth microlens 114, the fifth microlens 115, the sixth microlens 116, the seventh microlens 117, the eighth microlens 118, the ninth microlens 119, and the tenth microlens 120 shown in FIGS. 1 to 3, it is assumed that the light propagates from the air to the first light-transmitting piece 120, and the light from the air into the first light-transmitting piece 120 is referred to as incident light, which has a first incident angle r1, and the incident light has a large angle, such as the light propagating along the tangent direction of the right edge of the second first microlens 111; the light after refraction through the first light-transmitting piece 120 is referred to as first refracted light, which has a first refractive angle r2; and the light after refraction through the first microlens 111 is referred to as second refracted light, which has a second refractive angle r3.

[0084] wherein the refractive index of the air is denoted as n1, the refractive index of the first light-transmitting piece 120 is denoted as n2, and the refractive index of the first microlens is denoted as n3.

[0085] According to the formula for calculating the refractive angle of light propagating in different medium layers: sin(r1)×(n1)=sin(r2)×(n2), since n2 is greater than n1, the first refractive angle r2 is smaller than the first incident angle r1, and the incident light with the first incident angle is deflected toward the second first microlens 111 after refraction through the first light-transmitting piece 120, thereby preventing the first refracted light from being deflected toward the third first microlens 111, and the incident light enters the first microlens array 110 at a smaller incident angle, thereby avoiding interference between the adjacent two first microlenses 111.

[0086] In this way, the second refracted light formed by the incident light with a large angle is transmitted to one of the first microlenses 111, thereby reducing the interference between the adjacent first microlenses 111, and increasing the amount of light received by the first microlens 111, thereby improving the performance of the photoelectric conversion device using the microlens assembly.​

[0087] It should be understood that the relationship between the refractive index of the first light-transmitting member 120 and the first microlens array 110 can be different, for example, the refractive index of the first light-transmitting member 120 can be less than the refractive index of the first microlens array 110. In this way, the wavelength of the incident light is reduced again, so that the incident light has a smaller wavelength, and a smaller diameter of the image can be obtained, thereby improving the resolution of the imaging system. At the same time, the refractive index of the first light-transmitting member 120 can be less than the refractive index of the first microlens array 110, so that the incident light again enters from the optically sparse to the optically dense, avoiding the interference of the incident light between the adjacent two first microlenses 111.

[0088] For another example, the refractive index of the first light-transmitting member 120 can be greater than the refractive index of the first microlens array 110. In this embodiment, the wavelength of the light entering the first light-transmitting member 120 is shortened and the refraction angle of the light entering the first light-transmitting member 120 is reduced by the arrangement of the first light-transmitting member 120. Even if the first microlens array 110 performs a micro-diffusion on the incident light, it will not affect the above beneficial effects, and the technical effects of improving the resolution of the optical system and preventing the interference of the incident light between the adjacent two first microlenses 111 can be achieved.

[0089] In this embodiment, the top surface of the first light-transmitting member 120 can be a plane or uneven, which is not limited in this embodiment.

[0090] In some embodiments, as shown in Figures 6 to 10 The microlens assembly 100 further includes a second light-transmitting member 130, which is arranged between the first light-transmitting member 120 and the first microlens array 110, and the refractive index of the second light-transmitting member 130 is less than the refractive index of the first light-transmitting member 120 and the first microlens array 110.

[0091] The second light-transmitting member 130 at least partially fills between the adjacent first microlenses 111, wherein the top surface of the second light-transmitting member 130 can be flush with the top surface of the first microlens 111, or lower than the top surface of the first microlens 111, or the top surface of the second light-transmitting member 130 is higher than the top surface of the first microlens 111. In this way, the arrangement of the first light-transmitting member 120 is facilitated, and the convenience of preparation of the first light-transmitting member 120 is improved.

[0092] If the top surface of the second light-transmitting piece 130 is flush with or higher than the top surface of the first microlens 111, so that the edge of each first microlens 111 is wrapped by the second light-transmitting piece 130, no matter from which position of the edge of the first microlens 111 the large-angle light ray is incident, the large-angle light ray can be refracted by the first light-transmitting piece 120 and the second light-transmitting piece 130 to form a refracted light ray with a small angle, so that the light ray is deflected towards the first microlens 111 corresponding to the light ray, thereby reducing the interference of the incident light ray between adjacent first microlenses 111.

[0093] In addition, the refracted light ray with a small angle can be used as a small-angle incident light ray entering the first microlens 111, thereby improving the amount of light received by the first microlens 111 and improving the performance of the photoelectric conversion device using the microlens assembly.

[0094] In the embodiment, as shown in Figure 11 The second light-transmitting piece 130 can have a first height H1, i.e., the vertical distance between the top surface of the second light-transmitting piece 130 and the bottom surface of the first microlens array 110.

[0095] By increasing the height of the second light-transmitting piece 130 in the direction perpendicular to the first microlens array 110, the focal length of the imaging system can be reduced, the diameter of the formed image after passing through the first microlens array 110 can be reduced, and the resolution of the imaging system can be improved. In addition, the second refracted light ray formed by the incident light ray with a large angle can be transmitted to one of the first microlenses 111, thereby reducing the interference of the incident light ray between adjacent first microlenses 111. Furthermore, the amount of light received by the first microlens 111 can be improved, and the performance of the photoelectric conversion device using the microlens assembly can be improved.

[0096] In some embodiments, the structure of the first light-transmitting piece 120 can be selected in various ways. In an example, as shown in Figure 6 In the vertical cross section perpendicular to the top surface of the second light-transmitting piece 130, the vertical cross section of the first light-transmitting piece 120 is rectangular.

[0097] In this way, it can be ensured that the incident light ray with a large angle incident from each position of the top surface of the first light-transmitting piece 120 into the first light-transmitting piece 120 can reduce the refraction angle of the light ray entering the first light-transmitting piece 120, thereby making the light ray exiting the first microlens array 110 into an incident light ray with an incident angle, reducing the crosstalk of the incident light ray between adjacent photosensitive elements, and improving the performance of the photoelectric conversion device.

[0098] In another example, as shown in Figures 7 to 11As shown, the first light-transmitting member 120 includes a plurality of first light-transmitting portions 121, one first light-transmitting portion 121 corresponding to one or more first microlenses 111, that is, the projection of the first light-transmitting portion 121 on the first microlens array 110 has an overlapping area with at least one first microlens 111.

[0099] For example, as shown in the orientation from left to right, the projection of the first light-transmitting portion 121 on the first microlens array 110 is partially located on the first first microlens 111 and partially located on the second first microlens 111. Figure 7

[0100] For another example, as shown in the orientation from left to right, the projection of the first light-transmitting portion 121 on the first microlens array 110 is partially located on the first first microlens 111 and partially located on the second first microlens 111. Figure 8

[0101] In the embodiment, by setting the first light-transmitting portion 121 with a large refractive index on the first microlens array 110, the loss of the light rays with large incident angles can be prevented, and at the same time, the incident light rays from the two sides of the first light-transmitting portion 121 can enter different first microlenses 111 after refraction by the first light-transmitting portion 121, so as to reduce the interference between the light rays in adjacent first microlenses 111. At the same time, the light rays propagating from the environment medium into the first light-transmitting portion 121 can be converted into light rays with shorter wavelengths, so that the light rays with shorter wavelengths form an object image with a smaller diameter after imaging by the first microlens array 110, thereby improving the resolution of the imaging system.

[0102] In some embodiments, the plurality of first light-transmitting portions 121 can be arranged at intervals on the second light-transmitting member 130, that is, as shown in Figure 9 Figure 10 As shown, the plurality of first light-transmitting portions 121 can also be arranged in sequence on the second light-transmitting member 130, that is, as shown in Figure 7 Figure 8 As shown, the opposite bottoms of adjacent first light-transmitting portions 121 are connected together.

[0103] When there is an interval between adjacent first light-transmitting portions 121, the first light-transmitting portion 121 can also reflect the incident light rays to reduce the interference between the light rays in adjacent first microlenses 111.

[0104] In an example, the longitudinal section shape of the first light-transmitting portion 121 can be a semi-elliptical shape with a longitudinal section perpendicular to the plane on which the first microlens array 110 is located, and the structure is as shown in Figure 7 Figure 8 ​​​​​As shown, the longitudinal cross-sectional shape of the first light-transmitting part 121 can also be a trapezoid with a larger upper section and a smaller lower section, as shown in the diagram. Figure 9 As shown, the longitudinal cross-sectional shape of the first light-transmitting part 121 can also be rectangular, and its structure is as follows: Figure 10 As shown.

[0105] When the longitudinal cross-sectional shape of the first light-transmitting part 121 is trapezoidal or rectangular, along the first direction X, the first light-transmitting part 121 has a first side surface and a second side surface that are arranged opposite to each other. When incident light is transmitted to the first side surface and the second side surface, the first side surface and the second side surface act as a block, so that part of the light incident on the first side surface and the second side surface is reflected, so as to reflect the part of the light into different first microlenses, thereby reducing the interference of light between adjacent first microlenses 111.

[0106] In some embodiments, such as Figure 12 and Figure 13 As shown, each first light-transmitting part 121 includes a second microlens, and multiple second microlenses form a second microlens array. One second microlens corresponds to one or more first microlenses 111, wherein the second microlens is a convex lens.

[0107] It should be noted that, in this embodiment, the plurality of second microlenses and the plurality of first microlenses 111 can be configured in a one-to-one correspondence, for example, as shown in the example below. Figure 12 As shown, there are four first microlenses 111 and four second microlenses, with one second microlens disposed on each of the first microlenses 111.

[0108] The multiple second microlenses may not correspond one-to-one with the multiple first microlenses 111, for example, as Figure 13 As shown, there are four first microlenses 111 and five second microlenses.

[0109] Among them, such as Figure 12 As shown, the second microlens has a second focal point S2, which is formed within the second light-transmitting element 130. This arrangement allows the light output from one of the second microlenses to enter one of the first microlenses 111 in a relatively dispersed state, increasing the amount of light received by the first microlens. This ensures that the light on the photosensitive element layer is also relatively uniform, making the light received by each photosensitive element within the photosensitive element layer more uniform and improving the performance of the photoelectric conversion device.

[0110] In some embodiments, the second light-transmitting element 130 has a first thickness H1, and the maximum distance L1 from the second focal point S2 to the top surface of the second light-transmitting element 130 is not greater than half of the first thickness H1.

[0111] It should be noted that the first thickness of the second light-transmitting element 130 is Figure 12H1, as shown in the figure, can also be understood as the vertical distance between the top surface of the second light-transmitting piece 130 and the bottom surface of the first microlens array 110, and the distance from the second focal point S2 to the top surface of the second light-transmitting piece 130 is Figure 11 L1, as shown in the figure, in the embodiment, by regulating the position of the second focal point S2 in the second light-transmitting piece 130, part of the incident light rays entering from the second lens is guided to different sides of the first microlens 111, and then the light condensing effect of the first microlens 111 prevents the light rays from causing crosstalk effect between adjacent photosensitive elements.

[0112] In addition, the focal length of the imaging system can also be reduced, and the diameter of the formed image after passing through the first microlens array 110 can be reduced, thereby improving the resolution of the imaging system.

[0113] It should be noted that in the embodiment, the curvatures of the second microlenses can be the same or different, which is not limited in the embodiment.

[0114] In some embodiments, the first microlens 111 has a first curvature, and the second microlens has a second curvature different from the first curvature.

[0115] Under the premise of ensuring that the second focal point is in the second light-transmitting piece 130, the curvatures of the first microlens 111 and the second microlens can be the same or different, so that the flexibility of the microlens assembly 100 can be increased.

[0116] Embodiment two

[0117] As Figures 14 to 23 shown, the application embodiment also provides a photoelectric conversion device, which can be applied to an imaging system, such as an image sensor.

[0118] The photoelectric conversion device includes a photosensitive element layer 200 and the microlens assembly 100 in the above embodiment.

[0119] The photosensitive element layer 200 includes a photosensitive element layer 210, and the photosensitive element layer 210 includes a plurality of photosensitive elements 211 and a separation structure 212 for separating each photosensitive element 211. One photosensitive element 211 corresponds to one or more first microlenses 111. The photosensitive element 211 is used to receive light transmitted through one or more first microlenses 111, and to convert the optical signal of the light into an electrical signal. The photosensitive element 211 includes a photosensitive diode, but is not limited thereto.

[0120] In this embodiment, a first light-transmitting element 120 and a second light-transmitting element 130 are disposed on the first microlens array 110. The refractive index of the first light-transmitting element 120 is greater than that of the ambient medium. This arrangement can, on the one hand, change the wavelength of the incident light, allowing light with a shorter wavelength to form an image with a smaller diameter after being imaged by the first microlens array, thereby improving the resolution of the imaging system. On the other hand, it can reduce the refraction angle of the incident light as it passes through the first light-transmitting element 120, the second light-transmitting element 130, and the refracted light entering the photosensitive element layer 200 after passing through the first microlens 111. This reduces crosstalk between adjacent photosensitive elements 211 caused by refracted light, thereby improving the performance of the photoelectric conversion device.

[0121] In some embodiments, the photosensitive element layer 200 further includes an interconnect layer 220, which is used to transmit the electrical signals of the photosensitive element 211. The interconnect layer 220 may include a dielectric layer and a plurality of interconnect structures 221, wherein the plurality of interconnect structures 221 are spaced apart in the dielectric layer and correspond one-to-one with the plurality of photosensitive elements 211, so as to transmit the optical signal on each photosensitive element 211 to the readout circuit in the peripheral circuit.

[0122] The dielectric layer may be made of insulating materials such as silicon oxide or silicon nitride, and the interconnect structure 221 may be made of metallic copper.

[0123] In this embodiment, the relative positional relationship between the interconnect layer 220, the photosensitive element layer 210, and the microlens assembly 100 can be selected in various ways, for example, as follows: Figures 14 to 21 As shown, the photosensitive element layer 210 and the microlens assembly 100 are sequentially disposed on the interconnect layer 220. That is, the photosensitive element layer 210 is disposed between the microlens assembly 100 and the interconnect layer 220, so that the pixel array in the photoelectric conversion device is a back-side illuminated (BSI) pixel array; for example, as Figure 22 As shown, the interconnect layer 220 and the microlens assembly 100 are stacked on the photosensitive element layer 210. That is, the interconnect layer 220 is disposed between the photosensitive element layer 210 and the microlens assembly 100, so that the pixel array in the photoelectric conversion device is a front-side illuminated (FSI) pixel array.

[0124] In some embodiments, such as Figure 23 As shown, the photosensitive element layer 200 also includes a filter layer 230, which includes multiple filter areas 231, and one filter area 231 corresponds to one or more first microlenses 111.

[0125] The embodiment can obtain required light of different wave bands through the arrangement of the plurality of filter regions, so as to improve the imaging effect of the photoelectric conversion device.

[0126] Exemplarily, as shown in the orientation, Figure 23 the first filter region 231 can pass only red corresponding wavelength light, the second filter region 231 can pass only green corresponding wavelength light, and the third filter region 231 can pass only blue corresponding wavelength light.

[0127] In some embodiments, an anti-reflection layer 240 is further arranged between the microlens assembly 100 and the photosensitive element layer 200, so as to reduce the reflection of light, so that more light is transmitted to the photosensitive element 211, and the performance of the image sensor is ensured. The material of the anti-reflection layer 240 can be one of or any combination of dielectric materials such as silicon oxide, hafnium oxide, silicon nitride, aluminum oxide, and thallium oxide.

[0128] It should be noted that in the embodiment, the anti-reflection layer 240 can be an integral layer structure, or can include a plurality of independently existing anti-reflection blocks, each of which corresponds to one photosensitive element 211 and one first microlens 111.

[0129] In some embodiments, continuing to refer to Figure 14 and Figure 15 , the first microlens 111 has a first focal point S1, the first focal point S1 is formed in the photosensitive element layer 210, the photosensitive element layer 210 has a second thickness H2, and the maximum distance L2 from the first focal point S1 to the bottom surface of the first microlens 111 is not less than one half of the second thickness H2. In this way, the focal length of the first microlens 111 can be increased, light crosstalk into adjacent photosensitive elements 211 can be prevented, and the performance of the photoelectric conversion device is improved.

[0130] Embodiment Three

[0131] The embodiment of the present disclosure also provides an imaging system, wherein the imaging system can include a digital still camera, a digital video camera, an image reading device (such as a scanner), a mobile phone, and the like.

[0132] As shown in Figure 24 , the imaging system includes the photoelectric conversion device in the above embodiments and a signal processing unit, the signal processing unit is used to process an output signal output from the photoelectric conversion device, to convert the output signal output from the photoelectric conversion device into a digital signal through analog-to-digital conversion, and the signal processing unit includes a microcomputer and various circuits, the microcomputer includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and the like.

[0133] Embodiment Four

[0134] AsFigure 25 As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps:

[0135] Step S100: providing a substrate, and forming a photosensitive element layer in the substrate.

[0136] The substrate can be made of a semiconductor material, which can be one or more of silicon, germanium, silicon-germanium compound and silicon-carbon compound.

[0137] As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps: Figure 26 As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps:

[0138] It should be noted that, when the pixel array in the photoelectric conversion device is a front-illuminated pixel array, an interconnection layer 220 needs to be formed on the lower surface of the photosensitive element layer 210, and a filter layer 230 and an anti-reflection layer 240 need to be formed on the upper surface of the photosensitive element layer 210, wherein the forming processes of the interconnection layer 220, the filter layer 230 and the anti-reflection layer 240 can be conventional preparation processes, and the embodiment will not be described in more details.

[0139] Step S200: forming a first microlens array on the photosensitive element layer, the first microlens array forming a first light receiving surface.

[0140] The first microlens array 110 comprises a plurality of first microlenses 111, and the top surfaces of the plurality of first microlenses 111 constitute a first light receiving surface 112.

[0141] As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps: Figure 27 As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps:

[0142] Then, the first lens material layer 140 is patterned according to an optical design to form a plurality of first microlenses 111 which are arranged in connection with or at intervals from each other, the plurality of first microlenses 111 constituting a first microlens array 110, and the first microlens array 110 having a first light receiving surface 112, and the structure thereof is shown in the above. Figure 29

[0143] As shown in the above, the embodiment of the present disclosure further provides a method for manufacturing the photoelectric conversion device, comprising the following steps: Figure 28 ​As shown, a photoresist layer 150 can be formed on the first lens material layer 140. The photoresist layer 150 is patterned to form a pattern within the photoresist layer 150. Using the patterned photoresist layer as a mask, a portion of the first lens material layer 140 is removed, and the remaining first lens material layer constitutes a plurality of first microlenses 111.

[0144] Step S300: A first light-transmitting element is formed on the first microlens array, covering the first light-receiving surface. The top surface of the first light-transmitting element constitutes the second light-receiving surface. Light rays propagating in the ambient medium are transmitted through the second light-receiving surface to the first light-receiving surface. The refractive index of the first light-transmitting element is greater than the refractive index of the ambient medium.

[0145] In this embodiment, by forming a first light-transmitting element 120 with a high refractive index on the first microlens array 110, the refractive index of the first light-transmitting element 120 being greater than that of the ambient medium, this configuration can, on the one hand, change the wavelength of the incident light, allowing light with a shorter wavelength to form an image with a smaller diameter after being imaged by the first microlens array, thereby improving the resolution of the imaging system. On the other hand, it can reduce the refraction angle of the refracted light after the incident light passes through the first light-transmitting element 120, the second light-transmitting element 130, and the first microlens 111 sequentially before entering the photosensitive element layer 200, reducing crosstalk between adjacent photosensitive elements 211 and improving the performance of the photoelectric conversion device.

[0146] In some embodiments, after the step of forming a first microlens array on the photosensitive element layer and before the step of forming a first light-transmitting element covering the first light-receiving surface on the first microlens array, the method of manufacturing a photoelectric conversion device further includes:

[0147] like Figure 30 As shown, a light-transmitting material layer 160 can be formed on the first microlens array 110 using a deposition process.

[0148] After that, as Figure 31 and Figure 32 As shown, a portion of the light-transmitting material layer 160 can be etched away to form a second light-transmitting element 130. The second light-transmitting element 130 at least fills the area between adjacent first microlenses 111, and the second light-transmitting element 130 has a flat top surface. The refractive index of the second light-transmitting element 130 is less than that of the first light-transmitting element 120 and the first microlens array 110.

[0149] The height of the second light-transmitting element 130 can be designed freely, as long as the top surface of the second light-transmitting element 130 is flat.

[0150] In some embodiments, the step of forming a first light-transmitting element covering the first light-receiving surface on the first microlens array includes:

[0151] As Figure 33 and Figure 34 shown, a second lens material layer 170 is formed covering the second light-transmitting member 130 by a deposition process, the second lens material layer 170 having a refractive index greater than the refractive index of the first microlens array 110 and the refractive index of the first light-transmitting member 120, and greater than the refractive index of the ambient medium.

[0152] The second lens material layer 170 is patterned according to an optical design to form the first light-transmitting member 120, the top surface of the first light-transmitting member 120 constituting the second light-receiving surface 122, and the structure is as shown in Figure 16 and Figure 17

[0153] In some embodiments, the second lens material layer 170 is patterned to form a plurality of first light-transmitting portions 121 arranged in connection with or spaced from each other, the plurality of first light-transmitting portions 121 constituting the second light-transmitting member 130, and the structure can continue to refer to Figures 18 to 21 .

[0154] Each of the first light-transmitting portions 121 includes a second microlens, and a plurality of second microlenses constitute a second microlens array, one second microlens corresponding to one or more first microlenses 111, the first microlens 111 having a first curvature, and the second microlens having a second curvature different from the first curvature.

[0155] In the present embodiment, the functions of the first light-transmitting member 120 and the second light-transmitting member 130 formed are the same as those of the first light-transmitting member 120 and the second light-transmitting member 130 in Embodiment One, and the present embodiment will not be described further.

[0156] Each of the embodiments or implementations in the present specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0157] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure.

[0158] In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0159] ​Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A microlens assembly, characterized by, The microlens assembly comprises: a first microlens array; a first light-transmitting member disposed on the first microlens array, the first light-transmitting member being configured to transmit light propagating in an ambient medium into the first microlens array, wherein the first light-transmitting member has a refractive index greater than that of the ambient medium; a second light-transmitting member disposed between the first light-transmitting member and the first microlens array; wherein the first light-transmitting member comprises a plurality of first light-transmitting portions, each of the first light-transmitting portions comprising a second microlens having a second focal point formed in the second light-transmitting member; the second light-transmitting member has a first thickness, and the maximum distance from the second focal point to the top surface of the second light-transmitting member is not greater than one half of the first thickness.

2. The microlens assembly of claim 1, wherein, The first light-transmitting member has a refractive index greater than that of the first microlens array.

3. The microlens assembly of claim 1 or 2, wherein, The second light-transmitting member has a refractive index less than that of the first light-transmitting member and the first microlens array.

4. The microlens assembly of claim 1 or 2, wherein, The first microlens array comprises a microlens array of convex lenses or a microlens array of concave lenses.

5. The microlens assembly of claim 1 or 2, wherein, The first microlens array comprises a plurality of first microlenses, and each of the first light-transmitting portions corresponds to one or more of the first microlenses; wherein each of the first microlenses comprises a convex lens or a concave lens.

6. The microlens assembly of claim 5, wherein, A second microlens array is formed by a plurality of the second microlenses, and each of the second microlenses corresponds to one or more of the first microlenses.

7. The microlens assembly of claim 5, wherein, Each of the first microlenses has a first curvature, and each of the second microlenses has a second curvature different from the first curvature.

8. A photoelectric conversion device, comprising: The microlens assembly comprises: a photosensitive element layer and the microlens assembly according to any one of claims 1-7; the microlens assembly is disposed on the photosensitive element layer.

9. The photoelectric conversion device according to claim 8, wherein The photosensitive element layer comprises a light-filtering layer comprising a plurality of light-filtering regions, each of the light-filtering regions corresponding to one or more of the first microlenses.

10. The photoelectric conversion device according to claim 9, wherein The photosensitive element layer further comprises a photosensitive element layer comprising a plurality of photosensitive elements, each of the photosensitive elements corresponding to one or more of the first microlenses.

11. The photoelectric conversion device according to claim 10, wherein Each of the first microlenses has a first focal point formed in the photosensitive element layer, and the photosensitive element layer has a second thickness, and the maximum distance from the first focal point to the bottom surface of the first microlens is not less than one half of the second thickness.

12. The photoelectric conversion device according to any one of claims 8 to 11, wherein An anti-reflection layer is further provided between the microlens assembly and the photosensitive element layer.

13. An imaging system characterized by, The photoelectric conversion device comprises: the photoelectric conversion device according to any one of claims 8-12; and a signal processing unit configured to process a signal output from the photoelectric conversion device.

14. A method of manufacturing a photoelectric conversion device, characterized by, The photoelectric conversion device comprises: providing a substrate in which a photosensitive element layer is formed; forming a first microlens array on the photosensitive element layer, the first microlens array forming a first light-receiving surface; forming a first light-transmitting member covering the first light-receiving surface on the first microlens array, the top surface of the first light-transmitting member constituting a second light-receiving surface through which light propagating in an ambient medium is transmitted to the first light-receiving surface, wherein the first light-transmitting member has a refractive index greater than that of the ambient medium; After the step of forming the first microlens array on the photosensitive element layer, before the step of forming the first light-transmitting member covering the first light-receiving surface on the first microlens array, the method further comprises: forming a light-transmitting material layer on the first microlens array; removing part of the thickness of the light-transmitting material layer to form a second light-transmitting member, the second light-transmitting member being arranged between the first light-transmitting member and the first microlens array; wherein, in the step of forming the first light-transmitting member covering the first light-receiving surface on the first microlens array, it comprises: forming a second lens material layer covering the second light-transmitting member, forming the first light-transmitting member by patterning the second lens material layer according to an optical design; wherein, the step of forming the first light-transmitting member by patterning the second lens material layer according to an optical design comprises: patterning the second lens material layer to form a plurality of first light-transmitting portions arranged in connection with or spaced from each other, each of the first light-transmitting portions comprising a second microlens; wherein, the first light-transmitting member comprises a plurality of first light-transmitting portions, the second microlens has a second focal point formed in the second light-transmitting member, the second light-transmitting member has a first thickness, and the maximum distance from the second focal point to the top surface of the second light-transmitting member is not greater than one half of the first thickness.

15. The method of claim 14, wherein, In the step of forming the first microlens array on the photosensitive element layer, it comprises: depositing a first lens material layer on the substrate on which the photosensitive element layer is formed; forming a plurality of first microlenses arranged in connection with or spaced from each other by patterning the first lens material layer according to an optical design.

16. The method of claim 15, wherein, The refractive index of the light-transmitting material layer is less than the refractive index of the first microlens array. The second light-transmitting member at least fills the area between adjacent first microlenses, and the second light-transmitting member has a flat top surface, wherein the refractive index of the second light-transmitting member is less than the refractive index of the first light-transmitting member and the first microlens array.

17. The method of claim 14, wherein, The refractive index of the second lens material layer is greater than the refractive index of the first microlens array and the refractive index of the second light-transmitting member.

18. The method of claim 15, wherein, A second microlens array composed of a plurality of second microlenses, one second microlens corresponding to one or more first microlenses.

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