Manufacturing method of curved surface image sensor chip

Abstract

According to the manufacturing method of the curved surface image sensor provided by the invention, the metal wires connected between the photosensitive unit arrays are pre-pressed to form the bending parts, so that when a plurality of photosensitive unit arrays form a curved surface, the breakage of the metal wires caused by inconsistent spacing of the photosensitive unit arrays of different view fields is avoided, and the quality of the curved surface image sensor is improved. The curved surface image sensor chip can be uniformly applied to the manufacturing process of a concave surface chip and a convex surface chip, the process difficulty of the curved surface image sensor chip is effectively reduced, the product yield is improved, the manufacturing cost is reduced, light rays can generally and vertically irradiate the photosensitive unit array, field curvature aberration is further avoided, and the imaging performance of a camera module is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more particularly, to a method for manufacturing a curved image sensor chip. Background Art

[0002] Currently, image sensors have been widely used in various fields that require digital imaging, such as in portable electronic devices such as mobile phones, laptops, and tablets, as imaging elements in camera modules.

[0003] In traditional imaging systems, the photosensitive surface is essentially a two-dimensional plane, such as film, CCD, or traditional CMOS image sensors. However, the optical system's image formation does not occur within a two-dimensional image plane, but rather on a curved surface symmetrical about the optical axis. This imaging defect is known as field curvature. Field curvature is a type of aberration. When taking photos with a lens exhibiting field curvature, when the focus is adjusted to the center of the frame, the image is sharp, but the peripheral images are blurred. Similarly, when the focus is adjusted to the periphery, the image is sharp, but the center image is blurred again. As portable electronic devices become increasingly thinner and lighter, the distance between the lens and image sensor in camera modules is being designed to be increasingly closer to reduce size and thickness. However, this close distance between the lens and image sensor leads to two problems: first, the optical path difference between the center and the edge of the image sensor increases after refraction through the lens; second, the angle between the light rays striking the photosensitive cells at the edge of the image sensor and the normal to the photosensitive cells increases. These two issues complicate optical system design, further exacerbate the impact of field curvature on imaging, and amplify the phenomenon of weakened light reaching the photosensitive cells at the corners, resulting in poorer overall image quality.

[0004] like Figure 1 The curved image sensor chip 102 shown can accommodate optical path differences across various fields of view, ensuring that light passing through the lens 101 is incident substantially perpendicularly on the photosensitive area. This mitigates field curvature aberrations, increases the light intensity received by the photosensitive unit, and enables the camera module to achieve even better performance. However, curved image sensor chips have not become widespread, primarily due to manufacturing difficulties and reliability issues.

[0005] There are two main manufacturing methods for curved image sensor chips. One is to bend a common planar image sensor chip through a special process. Since the large-area silicon wafer as the chip substrate has high rigidity, this method cannot obtain an image sensor chip with large curvature, the optical path difference is still large, the field curvature problem cannot be eliminated, and the effect is limited. The other is to first isolate multiple photoreceptor unit arrays 104 from each other on the chip substrate through deep trench isolation, and then connect the photoreceptor unit arrays 104 to each other through metal wires 105 for signal transmission. Then, the metal wires 105 between the photoreceptor unit arrays 104 are bent by a special device to form a curved surface of the multiple photoreceptor unit arrays 104, and the photoreceptor unit arrays 104 forming the curved surface are placed on a pre-bent substrate 103, thereby forming a curved image sensor chip 102. However, in the case of bending the chip 102, the distance between the photoreceptor unit arrays 104 in different regions cannot be kept consistent and there is a certain uncontrollable phenomenon. The distance between the photoreceptor unit arrays 104 in the center of the chip becomes too wide, and the distance between the photoreceptor unit arrays 104 at the edge of the chip is too narrow. In the process of bending the chip, the metal material needs to adapt to the stress of different bending angles, which is easy to cause the metal wires 105 to break, thereby causing defects. Therefore, the existing manufacturing method of the curved image sensor chip faces great process difficulty, low product yield, and high manufacturing cost, which are urgent technical problems to be solved. SUMMARY

[0006] The present application aims to provide a manufacturing method of a curved image sensor, which reduces the process difficulty of the curved image sensor chip, improves the product yield, and reduces the manufacturing cost.

[0007] Based on the above considerations, the present application provides a manufacturing method of a curved image sensor chip, comprising: a. forming multiple separated photoreceptor unit arrays on a planar substrate, and the metal wires between the photoreceptor unit arrays are provided with bending portions through pre-pressing treatment; b. placing the multiple photoreceptor unit arrays in a bendable auxiliary substrate, bending the auxiliary substrate to form a curved surface of the multiple photoreceptor unit arrays; c. removing the auxiliary substrate, and placing the multiple photoreceptor unit arrays forming the curved surface on a supporting curved substrate, thereby forming the curved image sensor chip.

[0008] Preferably, in the step a, the metal wires between the photoreceptor unit arrays are hydraulically bent to form the bending portions.

[0009] Preferably, in the step a, the pre-pressing pressure or the pre-pressing times of the center field of view and the edge field of view of the curved image sensor chip are controlled, so that the curvature of the metal wire bending portion of the center field of view is smaller than the curvature of the metal wire bending portion of the edge field of view.

[0010] Preferably, in step a, the bending direction of the bent portion of the metal wire is toward the planar base or away from the planar base.

[0011] Preferably, in step a, the bending directions of all the metal wire bending portions between the photosensitive unit arrays are consistent.

[0012] Preferably, in the step b, the auxiliary base is mold-bent or hydraulically bent and shaped.

[0013] Preferably, in step b, the curvature of the metal wire bending portion in the central field of view is smaller than the curvature of the metal wire bending portion in the edge field of view by controlling the stretching of the metal wire bending portion in the central field of view and / or the retraction of the metal wire bending portion in the edge field of view of the curved image sensor chip.

[0014] Preferably, in the step b, after the plurality of photosensitive unit arrays form a curved surface, the length of the metal wire between adjacent photosensitive unit arrays is greater than 1.5 times the spacing between adjacent photosensitive unit arrays.

[0015] Preferably, in step b, after the plurality of photosensitive unit arrays form a curved surface, the angle between the normals of any two adjacent photosensitive unit arrays in the central field of view of the curved surface image sensor chip is no greater than 5°.

[0016] Preferably, in step b, after the plurality of photosensitive unit arrays form a curved surface, the angle between the normals of any two adjacent photosensitive unit arrays within the edge field of view of the curved surface image sensor chip is no greater than 3°.

[0017] Preferably, in step c, the plurality of photosensitive unit arrays are bonded and fixed on the curved substrate.

[0018] Preferably, in the step c, after the plurality of photosensitive unit arrays are placed on the curved substrate, a medium with low light transmittance is filled between the plurality of photosensitive unit arrays.

[0019] Preferably, step a and step b can be performed alternately.

[0020] Preferably, the method comprises: S1. providing a first planar substrate having opposite first and second faces; S2. forming a plurality of pixel cell arrays on the first face of the first planar substrate, the plurality of pixel cell arrays being isolated from each other by first trenches and being in communication with each other by metal lines in the first trenches; S3. forming a bend in the metal lines between the plurality of pixel cell arrays by a pre-pressing process; S4. forming a bendable second auxiliary substrate on the first face of the first planar substrate and in the first trenches; S5. thinning the second face of the first planar substrate, forming a filter film array and a microlens array corresponding to the plurality of pixel cell arrays on the second face of the first planar substrate, each pixel cell array, together with a corresponding filter film array and microlens array, constituting a photosensitive cell array; S6. removing the first planar substrate between the photosensitive cell arrays to form second trenches, and forming a bendable third auxiliary substrate on the second face of the first planar substrate and in the second trenches; S7. bending the second auxiliary substrate and the third auxiliary substrate so that the plurality of photosensitive cell arrays form a curved surface; S8. removing the second auxiliary substrate and the third auxiliary substrate, and placing the plurality of photosensitive cell arrays forming the curved surface on a supported fourth curved substrate, thereby forming the curved image sensor chip.

[0021] Preferably, the first planar substrate is a semiconductor substrate.

[0022] Preferably, the second auxiliary substrate and the third auxiliary substrate are organic materials.

[0023] Preferably, the second auxiliary substrate and the third auxiliary substrate are the same or different materials.

[0024] Preferably, the fourth curved substrate is a curved package or a curved chip.

[0025] Preferably, the step S2 comprises: S21. forming a plurality of pixel cells arranged in an array on the first face of the first planar substrate, at least one of the pixel cells constituting a pixel cell array, the pixel cell arrays being isolated from each other by third trenches; S22. forming a filling layer in the third trenches, a dielectric layer on the first face of the first planar substrate, and a metal layer distributed in the dielectric layer and in communication with the pixel cells; S23. etching the dielectric layer and the filling layer between the pixel cell arrays to form the first trenches, and exposing the metal layer between the pixel cell arrays to form the metal lines in the first trenches.

[0026] Preferably, each pixel cell array comprises a plurality of pixel cells, the pixel cells inside the pixel cell array being isolated from each other by fourth trenches, and the width of the third trenches being greater than the width of the fourth trenches.

[0027] Preferably, each of the pixel unit arrays includes pixel units arranged in a 4×4 array.

[0028] Preferably, the metal lines between the pixel unit arrays in each row and the metal lines between the pixel unit arrays in each column are not in the same metal layer.

[0029] Preferably, the extension direction of the metal lines between the pixel unit arrays in each row is perpendicular to the extension direction of the metal lines between the pixel unit arrays in each column.

[0030] Preferably, the curved surface is a concave surface facing the lens or a convex surface facing the lens.

[0031] Preferably, the curved surface is a spherical surface or an aspherical surface.

[0032] The manufacturing method of the curved image sensor of the present invention forms a bent portion by pre-pressing the metal wires connected between the photosensitive unit arrays. When multiple photosensitive unit arrays form a curved surface, the metal wire breakage caused by inconsistent spacing between photosensitive unit arrays in different fields of view is avoided. The method can be uniformly applied to the manufacturing process of concave chips and convex chips, effectively reducing the process difficulty of curved image sensor chips, improving product yield, reducing manufacturing costs, and ensuring that light can be roughly vertically irradiated to the photosensitive unit array, thereby avoiding field curvature aberration and improving the imaging performance of the camera module. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0034] Figure 1 is a schematic diagram of a conventional curved image sensor chip; Figure 2 is a schematic diagram of a curved image sensor chip according to an embodiment of the present invention; Figure 3 is a schematic diagram of a curved image sensor chip according to another embodiment of the present invention; Figure 4 for Figure 2 Partial stereogram of area A in the middle edge field of view; Figure 5 for Figure 2 Partial side view of area A in the middle edge field of view; Figure 6 for Figure 2 Partial stereogram of area B in the central visual field; Figure 7 for Figure 2 Partial side view of area B in the central visual field; Figure 8 for Figure 3partial perspective view of the middle edge field A' region; Figure 9 for Figure 3 partial side view of the middle edge field A' region; Figure 10 for Figure 3 partial perspective view of the middle center field B' region; Figure 11 for Figure 3 partial side view of the middle center field B' region; Figure 12 flow chart of a method for manufacturing a curved image sensor chip according to an embodiment of the present application; Figures 13-25 schematic diagram of a manufacturing process of a curved image sensor chip according to an embodiment of the present application.

[0035] In the drawings, like or similar elements are designated with the same reference numerals throughout the several views. DETAILED DESCRIPTION

[0036] To solve the problems in the prior art, the present application provides a manufacturing method of a curved image sensor. A metal wire connected between arrays of photosensitive units is subjected to pre-pressing treatment to form a bending portion. When multiple arrays of photosensitive units form a curved surface, the metal wire is prevented from breaking due to inconsistent spacing of the arrays of photosensitive units in different fields of view. The manufacturing method can be applied to the manufacture of both concave and convex chips, effectively reduces the process difficulty of the curved image sensor chip, improves product yield, reduces manufacturing cost, and enables light to be substantially vertically incident on the array of photosensitive units, thereby avoiding field curvature aberration and improving the imaging performance of a camera module.

[0037] In the following detailed description of preferred embodiments, reference will be made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various embodiments in accordance with the present application. The embodiments are described in sufficient detail to enable those skilled in the art to practice the application, and it is to be understood that other embodiments can be utilized and that structural and logical changes can be made without departing from the scope of the present application. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present application is defined by the appended claims.

[0038] Figure 2 The structure and principle of a curved image sensor chip according to an embodiment of the present application are shown. The curved image sensor chip 202 includes a curved substrate 203 and multiple separate arrays of photosensitive units 204 on the curved substrate 203, wherein each array of photosensitive units 204 includes at least one photosensitive unit 207 (see Figures 4-7The multiple photosensitive cell arrays 204 form a concave surface facing the lens 201, so that light passing through the lens 201 can be irradiated substantially perpendicularly to the photosensitive cell array 204, thereby increasing the light intensity received by the photosensitive cells 207 and enabling the camera module to achieve even better performance. Preferably, the photosensitive cell array 204 can be fixed to the curved substrate 203 by bonding. The curved substrate 203 can be a curved package or a curved chip. Its material is not limited, but it must have a certain rigidity to support and protect the photosensitive cell array 204.

[0039] Field of View (FOV) refers to the maximum area that can be sensed by the image sensor in the imaging system. The area close to the optical axis of the lens can be called the central field of view, and the area away from the optical axis of the lens can be called the peripheral field of view. There is no unified standard for the division of the central field of view and the peripheral field of view. For example, the 1 / 2 area close to the optical axis of the lens, that is, the 0.5 field of view, can be called the central field of view, and the 1 / 2 area away from the optical axis, that is, the 0.5-1.0 field of view, can be called the peripheral field of view. Figure 2 In the illustrated embodiment, the edge viewing field A region and the center viewing field B region are merely rough divisions, which are used as examples for detailed description. Figure 4 、 Figure 5 They are Figure 2 Partial stereogram and side view of area A in the middle edge field of view; Figure 6 、 Figure 7 They are Figure 2 Partial stereoscopic and side views of area B in the central field of view.

[0040] It can be understood by those skilled in the art that Figure 2 The number of photosensitive unit arrays 204 is only an example. In actual applications, the number of photosensitive unit arrays 204 in the curved image sensor chip, the number of photosensitive units 207 in each photosensitive unit array 204, and the arrangement thereof may also vary depending on the resolution of the curved image sensor chip. Figures 4-7 In the illustrated embodiment, the number and internal arrangement of the photosensitive cells 207 in each photosensitive cell array 204 are identical (each photosensitive cell array 204 includes photosensitive cells 207 arranged in a 4×4 array), and the multiple separate photosensitive cell arrays 204 are regularly arranged on the curved substrate 203. In other embodiments not shown, the number of photosensitive cells 207 included in each photosensitive cell array 204 may also vary. For example, the photosensitive cell array 204 in the central field of view B may have a larger area and include a larger number of photosensitive cells 207, while the photosensitive cell array 204 in the peripheral field of view A may have a smaller area and include fewer photosensitive cells 207.

[0041] It should be noted that the separation here refers to the semiconductor substrate region forming photodiodes, MOS transistors and the like in each photosensitive unit array 204 being separated from each other by trenches; but different photosensitive unit arrays 204, for example, adjacent photosensitive unit arrays 204 in the same row and / or the same column of the array-arranged photosensitive unit arrays 204, can still be connected by metal wires 205 (for example, copper wires, aluminum wires or other metal interconnection materials) therebetween for signal transmission. Among them, according to the number of photosensitive units 207 contained in the photosensitive unit array 204 and the arrangement manner of the photosensitive units 207, the number and length of the metal wires 205 between the adjacent photosensitive unit arrays 204 can also be different. The length of the metal wire 205 referred to in this paper refers to the length of the metal wire 205 between different photosensitive unit arrays 204, and does not include the area of the metal wire 205 within the photosensitive unit array 204. Preferably, the length of the metal wire 205 between adjacent photosensitive unit arrays 204 is greater than 1.5 times the spacing between adjacent photosensitive unit arrays 204 after the formation of the curved surface, so as to ensure that the bending space of the metal wire 205 will not be too small in the subsequent metal wire bending and substrate bending processes.

[0042] The present application provides a manufacturing method of a curved surface image sensor chip, comprising: step a. forming a plurality of separated photosensitive unit arrays 204 on a planar substrate (i.e. a semiconductor substrate), and the metal wires 205 connected between the photosensitive unit arrays 204 are provided with bending portions 206 through pre-pressing treatment (for example, through hydraulic bending); step b. placing the plurality of photosensitive unit arrays 204 in a bendable auxiliary substrate (not shown), and bending the auxiliary substrate (for example, through mold bending or hydraulic bending and shaping) to make the plurality of photosensitive unit arrays 204 form a curved surface; step c. removing the auxiliary substrate, and placing the plurality of photosensitive unit arrays 204 forming a curved surface on a supported curved surface substrate 203, thereby forming the curved surface image sensor chip. Since the metal wires 205 connected between the photosensitive unit arrays 204 are provided with bending portions 206 through pre-pressing treatment, the bending portions 206 of the metal wires 205 have good toughness and can stretch and retract within a certain range during the process of bending the auxiliary substrate to make the plurality of separated photosensitive unit arrays 204 form a curved surface, thereby avoiding the breakage of the metal wires 205 due to the inconsistent spacing of the photosensitive unit arrays 204 of different fields of view, effectively reducing the process difficulty of the curved surface image sensor chip, improving the product yield, reducing the manufacturing cost, realizing that the light can be substantially vertically irradiated to the photosensitive unit array, thereby avoiding the field curvature aberration and improving the imaging performance of the camera module.

[0043] After the curved surface is formed, the pitch of the photosensitive unit array 204 in the central field of view B region is relatively large, and the pitch of the photosensitive unit array 204 in the edge field of view A region is relatively small, that is, the photosensitive unit array 204 in the central field of view B region is distributed more sparsely, and the photosensitive unit array 204 in the edge field of view A region is distributed more compactly. See Figure 4 、 Figure 5 In contrast to Figure 6 、 Figure 7 After the curved surface is formed, the curvature of the metal wire bending portion 206 in the central field of view B region is smaller than the curvature of the metal wire bending portion 206 in the edge field of view A region, so as to adapt to the distribution mode that the pitch of the photosensitive unit array 204 in the central field of view B region is larger than the pitch of the photosensitive unit array 204 in the edge field of view A region. Specifically, in the above step a, the curvature of the metal wire bending portion in the central field of view B region can be made smaller than the curvature of the metal wire bending portion in the edge field of view A region by controlling the pre-pressing pressure or the pre-pressing times of the central field of view B region and the edge field of view A region. In the above step b, the curvature of the metal wire bending portion in the central field of view B region can be made smaller than the curvature of the metal wire bending portion in the edge field of view A region by controlling the stretching of the metal wire bending portion in the central field of view B region and / or the retraction of the metal wire bending portion in the edge field of view A region. Of course, the above two methods can also be combined, and in the case that the curvature of the metal wire bending portion obtained by the pre-pressing treatment cannot meet the requirements, the curvature of the metal wire bending portion is further adjusted by the secondary bending treatment.

[0044] Preferably, after the curved surface is formed, the normal line included angle of any two adjacent photosensitive unit arrays 204 in the central field of view B region is not greater than 5°, so as to ensure that the resolution of the central field of view cannot be too small; and the normal line included angle of any two adjacent photosensitive unit arrays 204 in the edge field of view A region is not greater than 3°, so as to ensure the consistency of the resolution of the whole chip.

[0045] In addition, see Figures 4-7In this embodiment, adjacent photosensitive cell arrays 204 in the same row are connected via metal wires 205a therebetween, with the metal wires 205a having a bend 206a. Adjacent photosensitive cell arrays 204 in the same column are connected via metal wires 205b therebetween, with the metal wires 205b having a bend 206b. The metal wires 205a between the photosensitive cell arrays 204 in each row and the metal wires 205b between the photosensitive cell arrays 204 in each column are not on the same metal layer, and the metal wires 205a between the photosensitive cell arrays 204 in each row extend perpendicular to the metal wires 205b between the photosensitive cell arrays 204 in each column. Whether it is the metal wire 205a between each row of the photosensitive unit array 204 or the metal wire 205b between each column of the photosensitive unit array 204, the bending direction of its bending portion 206a, 206b is consistent, and is shown here as bending toward the direction of the semiconductor substrate in the photosensitive unit array 204 (i.e., bending upward).

[0046] In such Figure 3 、 Figures 8-11 In another embodiment shown, the bending direction of the bent portion 306 of the metal wire 305 is away from the semiconductor substrate in the photosensitive unit array 304 (i.e., it bends downward). Those skilled in the art can select the bending direction of the metal wire according to different manufacturing processes and form a bent portion in the metal wire connecting the photosensitive unit array through pre-pressing.

[0047] The above embodiments are all described using a concave chip facing the lens as an example. Those skilled in the art will understand that the manufacturing method of the curved image sensor chip of the present invention can be uniformly applied to the manufacturing process of concave chips and convex chips. That is to say, in other embodiments not shown, the curved surface of the image sensor chip can also be a convex surface facing the lens. In addition, the curved surface can be a spherical surface or an aspherical surface, so as to flexibly adjust the chip curvature to meet the requirements of different shooting needs for the chip curvature, so that the light can be roughly vertically irradiated to the photosensitive unit array, thereby avoiding field curvature aberrations and improving the imaging performance of the camera module.

[0048] See again Figures 4-7 Each photosensitive unit 207 in the photosensitive unit array 204 includes a pixel unit 208, a filter film 209 located on the pixel unit 208, and a microlens 210 located on the filter film. In actual production processes, the steps of forming multiple photosensitive unit arrays 204, forming the metal wire bending portion 206, and placing the photosensitive unit array 204 in the auxiliary substrate can be performed in an interleaved manner. In other words, the above steps a and b can be performed in an interleaved manner. Figures 12-25 Show Figure 2 、 Figures 4-7A preferred embodiment of the curved image sensor chip manufacturing method in the embodiments, wherein, Figure 12 is a method flow chart, Figures 13-25 is a cross-sectional schematic diagram. The method comprises the following steps.

[0049] Step S1. A first planar substrate (i.e. a semiconductor substrate) 1001 is provided, which has opposite first and second faces 1001A and 1001B.

[0050] Step S2. A plurality of pixel cell arrays 1002 are formed on the first face 1001A of the first planar substrate 1001, which are isolated from each other by first trenches 1007 and are in communication with each other by metal lines 205 in the first trenches 1007.

[0051] Specifically, the step S2 can further comprise: Step S21. A plurality of pixel cells 208 arranged in an array are formed on the first face 1001A of the first planar substrate 1001, at least one of the pixel cells 208 constituting the pixel cell array 1002, which are isolated from each other by third trenches 1003 (see Figure 13 ). According to the present embodiment, each of the pixel cell arrays 1002 actually comprises 4x4 pixel cells 208 arranged in an array, which can be isolated from each other by fourth trenches (not shown) inside the pixel cell array 1002, the width of the third trenches 1003 being greater than that of the fourth trenches.

[0052] Step S22. A filling layer 1004 is formed in the third trenches 1003 (see Figure 14 ), a dielectric layer 1006 is formed on the first face 1001A of the first planar substrate 1001, and a metal layer 1005 is distributed in the dielectric layer 1006 to communicate with the pixel cells 208 (see Figure 15 ). The material of the filling layer 1004 and the dielectric layer 1006 can be a common dielectric, such as silicon oxide, silicon nitride, silicon oxynitride; the material of the metal layer 1005 is preferably copper, aluminum or other metal interconnection material.

[0053] Step S23. The dielectric layer 1006 and the filling layer 1004 between the pixel cell arrays 1002 are etched to form first trenches 1007, and the metal layer 1005 between the pixel cell arrays 1002 is exposed to form metal lines 205 in the first trenches 1007 (see Figure 16). Preferably, the metal lines 205a between each row of pixel cell arrays 1002 are not in the same metal layer as the metal lines 205b between each column of pixel cell arrays, and the extension direction of the metal lines 205a between each row of pixel cell arrays 1002 is perpendicular to the extension direction of the metal lines 205b between each column of pixel cell arrays, which can be referred to in detail in Figures 4-7 . However, in Figures 16-25 , the metal lines 205 are uniformly simplified for illustration.

[0054] Step S3. After forming the metal lines 205 between the plurality of pixel cell arrays 1002, the metal lines 205 between the plurality of pixel cell arrays 1002 are formed with bending portions 206 by pre-pressing (see Figure 17 ). For example, the metal lines 205 between the plurality of pixel cell arrays 1002 are formed with the bending portions 206 by hydraulic bending. Preferably, the pre-pressing pressure or the pre-pressing times of the central field of view B region and the edge field of view A region are controlled so that the curvature of the metal line bending portion of the central field of view B region is smaller than the curvature of the metal line bending portion of the edge field of view A region, which can be referred to in detail in Figures 4-7 . However, in Figures 17-25 , the change of curvature is not illustrated for simplicity. In the embodiment, the bending directions of all the metal line bending portions 206 between the plurality of pixel cell arrays 1002 are consistent, all being towards the planar substrate 1001 (i.e. bending downwards in Figure 17 ). In other embodiments not shown, the bending directions can be away from the planar substrate 1001.

[0055] Step S4. A bendable second auxiliary substrate 1008 is formed in the first face 1001A of the first planar substrate and in the first groove 1007 (see Figure 18 ). The second auxiliary substrate 1008 is preferably of organic material, such as organic glue.

[0056] Step S5. The first planar substrate 1001 is inverted, the second face 1001B of the first planar substrate is thinned, and a filter film array 1009 and a microlens array 1010 corresponding to the plurality of pixel cell arrays 1002 are formed on the second face 1001B of the first planar substrate, each pixel cell array 1002 and the corresponding filter film array 1009 and microlens array 1010 together constituting a photosensitive cell array 204. At this point, the pixel cell 208 contained in each photosensitive cell 207 in the photosensitive cell array 204, the filter film 209 on the pixel cell 208, and the microlens 210 on the filter film are all completed (see Figure 19 , Figure 20 ).

[0057] Step S6. Remove the first planar substrate 1001 between the array of photosensitive units to form a second groove 1011, and form a bendable third auxiliary substrate 1012 in the second surface 1001B of the first planar substrate and the second groove 1011 (see Figure 20 , Figure 21 ). The third auxiliary substrate 1012 is preferably of organic material, and can be the same as or different from the second auxiliary substrate.

[0058] Step S7. Bend the second auxiliary substrate 1008 and the third auxiliary substrate 1012 so that the plurality of array of photosensitive units 204 form a curved surface (see Figure 22 , Figure 23 ). In this embodiment, the auxiliary substrate is bent and shaped by a mold 1013, but can also be bent and shaped by hydraulic pressure. Preferably, the curvature of the metal wire bending portion in the central field of view B region is less than that of the metal wire bending portion in the edge field of view A region by controlling the stretching of the metal wire bending portion in the central field of view B region and / or the retraction of the metal wire bending portion in the edge field of view A region, and can be referred to in detail in Figures 4-7 . In addition, a larger length of the metal wire can be reserved to ensure that the bending space of the metal wire 205 is not too small during the bending of the metal wire and the auxiliary substrate, so that the length of the metal wire 205 between adjacent array of photosensitive units 204 is greater than 1.5 times the distance between adjacent array of photosensitive units 204 after the curved surface is formed. Further preferably, the angle between the normals of any two adjacent array of photosensitive units 204 in the central field of view B region is not greater than 5° to ensure that the resolution of the central field of view is not too small, and the angle between the normals of any two adjacent array of photosensitive units 204 in the edge field of view A region is not greater than 3° to ensure the resolution consistency of the overall chip.

[0059] Step S8. Remove the second auxiliary substrate 1008 and the third auxiliary substrate 1012, and place the plurality of array of photosensitive units 204 forming a curved surface on a supporting fourth curved substrate 203 to form the curved image sensor chip (see Figure 24 , Figure 25). Preferably, the photosensitive unit array 204 can be fixed on the curved substrate 203 by bonding, and the curved substrate 203 can be a curved package or a curved chip, which is not limited in material, but needs to have a certain rigidity to support and protect the photosensitive unit array 204. In addition, after the plurality of photosensitive unit arrays 204 are placed on the curved substrate 203, a low-transmittance medium (not shown) such as a material with a transmittance lower than 10% can be further filled between the plurality of photosensitive unit arrays 204 to reduce the light transmission flux. The low-transmittance medium is used to fill the gap between the mutually separated photosensitive unit arrays 204, further preventing or reducing the light crosstalk that can occur between different photosensitive unit arrays 204. In particular, for the case of each photosensitive unit array 204 including only one photosensitive unit, the low-transmittance medium further reduces or substantially eliminates the light crosstalk between adjacent photosensitive units.

[0060] In summary, the manufacturing method of the curved image sensor of the present application, by the metal wires connected between the photosensitive unit arrays being pre-pressed to form a bending part, when the plurality of photosensitive unit arrays form a curved surface, avoids the metal wire breakage caused by the inconsistent spacing of the photosensitive unit arrays of different fields of view, can be uniformly applied to the manufacturing process of the concave chip and the convex chip, effectively reduces the process difficulty of the curved image sensor chip, improves the product yield, reduces the manufacturing cost, realizes that the light can be substantially vertically irradiated to the photosensitive unit array, further avoids the field curvature aberration, and improves the imaging performance of the camera module.

[0061] It is apparent for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as exemplary and non-limiting. In addition, it is obvious that the word "comprising" does not exclude other elements and steps, and the word "one" does not exclude a plurality. The plurality of elements stated in the device claims can also be implemented by one element. The words first, second, etc. are used to indicate names, not any particular order.

Claims

1. A method for manufacturing a curved image sensor chip, characterized in that: include: a. forming a plurality of separate photosensitive unit arrays on a planar substrate, wherein the metal wires connected between the photosensitive unit arrays are pre-pressed to form a bent portion; b. placing the plurality of photosensitive unit arrays in a flexible auxiliary substrate, and bending the auxiliary substrate so that the plurality of photosensitive unit arrays form a curved surface; c. removing the auxiliary substrate, and placing the plurality of photosensitive unit arrays forming the curved surface on a supporting curved substrate, thereby forming the curved image sensor chip.

2. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step a, the metal wires between the photosensitive unit arrays are hydraulically bent to form the bent portions.

3. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In step a, the pre-pressing pressure or pre-pressing times of the central field of view and the edge field of view of the curved image sensor chip is controlled so that the curvature of the metal wire bending portion in the central field of view is smaller than the curvature of the metal wire bending portion in the edge field of view.

4. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step a, the bending direction of the bent portion of the metal wire is toward the planar base or away from the planar base.

5. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step a, the bending directions of all the metal wire bending portions between the photosensitive unit arrays are consistent.

6. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step b, the auxiliary base is mold-bent or hydraulically bent and shaped.

7. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In step b, the curvature of the metal wire bending portion in the central field of view is made smaller than the curvature of the metal wire bending portion in the edge field of view by controlling the stretching of the metal wire bending portion in the central field of view and / or the retraction of the metal wire bending portion in the edge field of view of the curved image sensor chip.

8. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step b, after the plurality of photosensitive unit arrays form a curved surface, the length of the metal wires between adjacent photosensitive unit arrays is greater than 1.5 times the spacing between adjacent photosensitive unit arrays.

9. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step b, after the multiple photosensitive unit arrays form a curved surface, the normal angle between any two adjacent photosensitive unit arrays in the central field of view of the curved surface image sensor chip is no more than 5°.

10. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step b, after the plurality of photosensitive unit arrays form a curved surface, the normal angle between any two adjacent photosensitive unit arrays within the edge field of view of the curved surface image sensor chip is no greater than 3°.

11. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step c, the plurality of photosensitive unit arrays are bonded and fixed on the curved substrate.

12. The method for manufacturing a curved image sensor chip according to claim 1, wherein: In the step c, after the plurality of photosensitive unit arrays are placed on the curved substrate, a medium with low light transmittance is filled between the plurality of photosensitive unit arrays.

13. The method for manufacturing a curved image sensor chip according to claim 1, wherein: Step a and step b can be performed alternately.

14. The method for manufacturing a curved image sensor chip according to claim 13, wherein: The method comprises: S1. Providing a first planar substrate, the first planar substrate having a first surface and a second surface opposite to each other; S2. forming a plurality of pixel unit arrays on the first surface of the first planar substrate, wherein the plurality of pixel unit arrays are isolated by a first trench and connected to each other through metal lines in the first trench; S3. forming a bent portion of the metal line between the plurality of pixel unit arrays by pre-pressing; S4. Forming a flexible second auxiliary substrate on the first surface of the first planar substrate and in the first groove; S5. Thinning the second surface of the first planar substrate, forming a filter film array and a microlens array corresponding to the plurality of pixel unit arrays on the second surface of the first planar substrate, wherein each pixel unit array, the corresponding filter film array, and the microlens array together constitute a photosensitive unit array; S6. removing the first planar substrate between the photosensitive unit array to form a second groove, and forming a flexible third auxiliary substrate on the second surface of the first planar substrate and in the second groove; S7. bending the second auxiliary substrate and the third auxiliary substrate so that the plurality of photosensitive unit arrays form a curved surface; S8. Remove the second auxiliary substrate and the third auxiliary substrate, and place the plurality of photosensitive unit arrays forming the curved surface on the supporting fourth curved surface substrate, thereby forming the curved surface image sensor chip.

15. The method for manufacturing a curved image sensor chip according to claim 14, wherein: The first planar base is a semiconductor substrate.

16. The method for manufacturing a curved image sensor chip according to claim 14, wherein: The second auxiliary substrate and the third auxiliary substrate are made of organic materials.

17. The method for manufacturing a curved image sensor chip according to claim 14, wherein: The second auxiliary substrate and the third auxiliary substrate are made of the same or different materials.

18. The method for manufacturing a curved image sensor chip according to claim 14, wherein: The fourth curved substrate is a curved package or a curved chip.

19. The method for manufacturing a curved image sensor chip according to claim 14, wherein: The step S2 comprises: S21. A plurality of pixel units arranged in an array are formed on the first surface of the first planar substrate, wherein at least one pixel unit constitutes the pixel unit array, and the pixel unit arrays are isolated by a third trench; S22. forming a filling layer in the third trench, forming a dielectric layer on the first surface of the first planar substrate, and a metal layer distributed in the dielectric layer and connected to the pixel unit; S23. Etching the dielectric layer and the filling layer between the pixel unit arrays to form a first trench, exposing the metal layer between the pixel unit arrays to form a metal line in the first trench.

20. The method for manufacturing a curved image sensor chip according to claim 19, wherein: Each of the pixel unit arrays includes a plurality of pixel units. The pixel units within the pixel unit array are isolated by a fourth trench. The width of the third trench is greater than the width of the fourth trench.

21. The method for manufacturing a curved image sensor chip according to claim 20, wherein: Each of the pixel unit arrays includes pixel units arranged in a 4×4 array.

22. The method for manufacturing a curved image sensor chip according to claim 19, wherein: The metal lines between the pixel unit arrays in each row and the metal lines between the pixel unit arrays in each column are not in the same metal layer.

23. The method for manufacturing a curved image sensor chip according to claim 19, wherein: An extension direction of the metal lines between the pixel unit arrays in each row is perpendicular to an extension direction of the metal lines between the pixel unit arrays in each column.

24. The method for manufacturing a curved image sensor chip according to claim 1, wherein: The curved surface is a concave surface facing the lens or a convex surface facing the lens.

25. The method for manufacturing a curved image sensor chip according to claim 1, wherein: The curved surface is a spherical surface or an aspherical surface.

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