Image sensor and electronic device

Abstract

According to the image sensor and the electronic equipment, the first welding pad is arranged at the position of the shading pixel area, and the first welding pad which is used for CP testing and packaging bonding is arranged on one side close to the shading pixel area in the process of preparing the welding pad in the peripheral area, so that the part of the first welding pad can be separated from the light-transmitting pixel area; therefore, the reflected light on the first welding pad almost falls on the shading pixel area, the reflected light is reduced or even prevented from entering the light-transmitting pixel area, the glare phenomenon is reduced, and the imaging quality of the image sensor is improved.

Description

Technical Field

[0001] This utility model relates to the field of CMOS image sensor technology, and in particular to an image sensor and electronic device. Background Technology

[0002] Image sensors utilize the photoelectric conversion function of optoelectronic devices to convert a light image on a photosensitive surface into an electrical signal proportional to the light image. Based on the different components, they can be divided into two main categories: CCD (Charge-Coupled Device) and CMOS (Metal-Oxide-Semiconductor). With the continuous development of CMOS image sensor (CIS) design and manufacturing processes, CMOS image sensors have gradually replaced CCD image sensors and become the mainstream.

[0003] The CIS structure is mainly divided into a pixel area and a peripheral area. The pixel area corresponds to one or more image pixels, the corresponding pixel circuits and optical components, while the peripheral area corresponds to the signal lines connecting the pixels and external devices, the peripheral circuits connected to the pixels and / or pads (PADs).

[0004] Currently, COB (Chip On Board) packaging is increasingly used in automotive products. COB packaging involves punching holes on the front side of the wafer (i.e., the PAD side). However, since the PAD used is shared by CP testing and packaging, the PAD can be damaged after the CP pin test. This reduces the wire bonding strength of the COB package during subsequent packaging, making wire bonding difficult and resulting in low packaging yield. At the same time, in CIS image sensors, glare caused by the structure around the pixel area is quite noticeable, especially in COB packaging applications, which can cause glare and reduce image quality.

[0005] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Utility Model Content

[0006] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide an image sensor and electronic device to solve the problem that the use of large PAD design in the COB packaging application of CIS image sensors in the prior art causes glare and leads to a reduction in image quality.

[0007] To achieve the above and other related objectives, this utility model provides an image sensor, the image sensor comprising:

[0008] A substrate having a front and a back side, the substrate including a pixel region and a peripheral region, the pixel region including at least a plurality of photoelectric conversion pixels, the peripheral region being disposed on the outer periphery of the pixel region; wherein, the pixel region includes a light-transmitting pixel region and a light-shielding pixel region, the light-shielding pixel region being disposed on at least one side outside the light-transmitting pixel region;

[0009] A plurality of solder pads are disposed on the outer periphery of the peripheral region and arranged along the extending direction of the outer periphery; wherein, the solder pads include a first solder pad, which is formed on the side close to the light-shielding pixel area, and the first solder pad includes a CP test area and a bonding area;

[0010] A light-shielding shielding layer is disposed on the light-shielding pixel area.

[0011] Optionally, it further includes a trench isolation structure and an electrical connection trench; wherein the trench isolation structure extends inward from the surface of the pixel region and the peripheral region, and the electrical connection trench extends inward from the surface of the peripheral region.

[0012] Optionally, the solder pad further includes a second solder pad, and the planar area of ​​the first solder pad is greater than the planar area of ​​the second solder pad.

[0013] Optionally, the planar area of ​​the first solder pad is between 2 and 5 times the planar area of ​​the second solder pad.

[0014] Optionally, the size range of the first pad is (80-100)μm×(140-180)μm, and the size range of the second pad is (70-90)μm×(70-90)μm.

[0015] Optionally, the first solder pad has a rectangular cross-sectional shape, and the second solder pad has a square cross-sectional shape.

[0016] Optionally, the cross-sections of the first and second solder pads are regular shapes, the center-to-center distance between two adjacent second solder pads is equal to the center-to-center distance between two adjacent first solder pads, and the dimension of the first solder pad facing the pixel region is greater than the dimension of the second solder pad facing the pixel region.

[0017] Optionally: a portion of the second solder pads are disposed on the same side as the first solder pads and arranged along the extending direction of the outer periphery; another portion of the second solder pads are disposed on other outer peripheries of the peripheral area.

[0018] Optionally, all the second solder pads are disposed on other outer peripheries outside the outer periphery of the outer periphery of the outer region where the first solder pad is located.

[0019] Optionally, all four ends of the outer perimeter of the peripheral region are configured as the second bonding pad.

[0020] Optionally, the first solder pad and the second solder pad are alternately spaced.

[0021] Optionally, the first pad is disposed at the corner of the pixel area, and the other peripheral areas are disposed as the second pad.

[0022] Optionally, the first pad is disposed on the adjacent side of the pixel region, and the remaining adjacent sides are disposed as the second pad.

[0023] Optionally, the first solder pad is disposed on the opposite side of the pixel region, and the second solder pad is disposed on the other opposite side of the pixel region.

[0024] Optionally, the light-shielding pixel area is disposed on opposite sides outside the light-transmitting pixel area.

[0025] Optionally, all the solder pads are first solder pads, disposed around the pixel area.

[0026] The present invention also provides an electronic device including an image sensor as described in any of the above claims.

[0027] As described above, the image sensor and electronic device of this utility model have the following beneficial effects: by setting the first pad at the position of the light-shielding pixel area, and by setting the first pad, which serves both CP testing and packaging bonding, at least on the side close to the light-shielding pixel area during the preparation of the pad in the peripheral area, the first pad can be separated from the light-transmitting pixel area. As a result, the reflected light on the first pad almost falls on the light-shielding pixel area, reducing or even avoiding the entry of reflected light into the light-transmitting pixel area, thereby reducing glare and improving the imaging quality of the image sensor. Attached Figure Description

[0028] Figures 1 to 20 The diagram shows the structural schematics of each step in the fabrication method of the image sensor of the present invention; wherein, Figure 1 This is a schematic diagram of the base. Figure 2 For along Figure 1 Cross-sectional view along the AA direction. Figure 4 This is a planar schematic diagram showing the distribution of the solder pad grooves in the substrate. Figure 9 This is a planar schematic diagram of the first solder pad. Figure 13 for Figure 12 A magnified view of a section at point B. Figure 15 for Figure 14 A magnified view of a section at point C. Figures 17 to 19 A schematic diagram of the cross-section generated during the formation of the filter array.

[0029] Figures 21 to 31The diagram shows several planar schematics illustrating the positional distribution of the solder pads in the image sensor of the present invention.

[0030] Figure 32 The diagram shows the spacing between two adjacent first pads in the image sensor of the present invention.

[0031] Figure 33 The diagram shows the spacing between two adjacent second pads in the image sensor of the present invention.

[0032] Component designation explanation

[0033] 10 base

[0034] 100 pixel area

[0035] 101 Transmitting Pixel Area

[0036] 102 light-shielding pixel area

[0037] 103 Outer Area

[0038] 11 Weld pad groove

[0039] 110 First Weld Pad Groove

[0040] 111 Second Weld Pad Groove

[0041] 12 layers of grid material

[0042] 13 solder pads

[0043] 130 First solder pad

[0044] 131 Second solder pad

[0045] 132 CP test area

[0046] 133 Bonding Zone

[0047] 14 Required grille

[0048] 15. Light-shielding layer

[0049] 16. Trench isolation structure

[0050] 17. Grooves for electrical connections

[0051] 18 Passivation layer

[0052] 19 Insulation layer

[0053] 20 layers of filter material

[0054] 21 Filter Layer

[0055] 210 Red light filter layer

[0056] 211 Green light filter layer

[0057] 212 Blue Light Filter Layer

[0058] 22-Filter Array

[0059] 23. Photomask

[0060] 24 Residue Detailed Implementation

[0061] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. For ease of explanation, when detailing the embodiments of the present invention, the cross-sectional views showing the device structure are partially enlarged, not according to the general scale, and the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. Furthermore, in actual manufacturing, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0062] For ease of description, spatial relation terms such as "below," "below," "lower than," "below," "above," and "upper" may be used herein to describe the relationship between an element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for the device in use or operation. Furthermore, when a layer is referred to as being "between" two layers, it may be the only layer between the two layers, or there may be one or more layers in between. Additionally, "between" as used in this invention includes both endpoint values. In the context of this application, the described structure of a first feature "above" a second feature may include embodiments where the first and second features are formed in direct contact, or embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0063] Please see Figures 1 to 28 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0064] Example 1

[0065] This embodiment provides a method for fabricating an image sensor, the method comprising the following steps:

[0066] S1, providing a substrate having opposing front and back sides, the substrate including a pixel region and a peripheral region, the pixel region including at least a plurality of photoelectric conversion pixels, the peripheral region being disposed on the outer periphery of the pixel region; wherein, the pixel region includes a light-transmitting pixel region and a light-shielding pixel region, and the light-shielding pixel region being disposed on at least one side outside the light-transmitting pixel region;

[0067] S2, a plurality of solder pad grooves are formed from the surface of the outer periphery of the peripheral area inward, and the solder pad grooves are arranged along the extension direction of the outer periphery; wherein, the solder pad groove includes a first solder pad groove, and the first solder pad groove is formed on the side close to the light-shielding pixel area.

[0068] S3, depositing a grid material layer on the substrate;

[0069] S4, fill the pad trench with pad material to form a pad; wherein, the pad includes a first pad formed at the first pad trench, and the first pad includes a CP test area and a bonding area;

[0070] S5, the grid material layer is patterned to form the desired grid in the light-transmitting pixel area, and a light-shielding shielding layer is formed in the light-shielding pixel area.

[0071] In one example, the light-shielding layer and the required grid for the light-transmitting pixel area are formed based on the same process, that is, both are formed based on the patterning process of the same grid material layer. In this case, the light-shielding layer is also called the light-shielding layer.

[0072] Specifically, the area of ​​the first bonding pad with multiplexing function is generally relatively large, so the reflection of light on the first bonding pad has a significant impact. When the reflected light enters the light-transmitting pixel area, it will cause glare. In image sensors, in order to achieve black level (BLC) detection, a light-shielding pixel area is set in the pixel area. By setting a light-shielding shielding layer in the light-shielding pixel area, the incident light is blocked. In the image sensor fabrication method of this embodiment, the first bonding pad is set according to the position of the light-shielding pixel area. By placing the first bonding pad, which is used for both CP testing and packaging bonding, on the side close to the light-shielding pixel area during the bonding pad fabrication process in the peripheral area, this part of the first bonding pad can be separated from the light-transmitting pixel area. Thus, the reflected light on this part of the first bonding pad almost falls on the light-shielding pixel area, reducing or even avoiding the reflected light from entering the light-transmitting pixel area, thereby reducing glare and improving the imaging quality of the image sensor. In addition, regarding the design of the first pad in this application, namely the large PAD design, a large PAD is divided into two areas for use. One area is used for CP pin piercing test, and the other area is used for COB packaging. The large PAD design effectively solves the problem of low wire bonding yield in COB packaging.

[0073] As an example, the size range of the first pad is (80-100) μm × (140-180) μm; for example, the cross-sectional shape of the first pad can be rectangular, corresponding to dimensions of 80μm × 140μm, 85μm × 140μm, 90μm × 160μm, 100μm × 180μm, etc. Furthermore, the distance between the centers of adjacent first pads is between 160μm and 180μm, for example, it can be 165μm, 170μm, 175μm, 180μm, 185μm, etc. In another example, the boundary line between the CP test area and the bonding area of ​​the first pad is set perpendicular to the edge of the pixel area. For example, for the first pad above the pixel area, the left area is used for CP testing and the right area is used for encapsulation bonding; for the first pad to the right of the pixel area, the upper area is used for CP testing and the lower area is used for encapsulation bonding.

[0074] The fabrication method of the image sensor in this embodiment will be described in detail below with reference to the specific accompanying drawings.

[0075] like Figure 1 and Figure 2As shown, step S1 is performed first, providing a substrate 10 with opposing front and back sides. The substrate 10 includes a pixel region 100 and a peripheral region 103. The pixel region 100 includes at least a plurality of photoelectric conversion pixels, and the peripheral region 103 is disposed on the outer periphery of the pixel region 100. The pixel region 100 includes a light-transmitting pixel region 101 and a light-shielding pixel region 102, and the light-shielding pixel region 102 is disposed on at least one side outside the light-transmitting pixel region 101. Figure 1 The light-shielding pixel area 102 is located on one side outside the light-transmitting pixel area 101. Of course, depending on actual needs, the light-shielding pixel area 102 can also be located on both sides or three sides outside the light-transmitting pixel area 101. In practice, the light-shielding pixel area 102 can also be located on opposite sides outside the light-transmitting pixel area 101.

[0076] In the structure of the image sensor, the pixel region 100 includes multiple photoelectric conversion pixels. Depending on actual needs, it generally also includes pixel circuits corresponding to the photoelectric conversion pixels (e.g., components included in 3T, 4T, 5T, 6T sensors, or pixel circuits used for control, readout, etc.). The pixel region 100 in the figure does not show the optical components corresponding to the photoelectric conversion pixels. In this implementation, the optical components corresponding to the photoelectric conversion pixels are fabricated from the front side of the substrate to form a back-illuminated image sensor.

[0077] The peripheral area 103 is generally provided with signal lines connecting the photoelectric conversion pixel and external devices, peripheral circuits connected to the photoelectric conversion pixel, and related components (such as solder pads).

[0078] like Figure 4 and Figure 5 As shown, then step S2 is performed, forming a plurality of solder pad grooves 11 from the surface of the outer periphery of the peripheral region 103 inward, and the solder pad grooves 11 are arranged along the extending direction of the outer periphery. For example, a plurality of solder pad grooves 11 are formed from the back surface of the substrate of the outer periphery of the peripheral region 103 inward, such as... Figure 4 In the process, the solder pad grooves 11 are disposed on three sides of the outer periphery of the peripheral region 103, and the solder pad grooves 11 on each side are arranged sequentially along the side length direction; wherein, the solder pad grooves 11 include a first solder pad groove 110, and the first solder pad groove 110 is formed on the side close to the light-shielding pixel area 102.

[0079] The solder pad trenches 11 are filled with pad material in subsequent processes to form solder pads, providing electrical contact with one or more components of the image sensor (e.g., the associated control circuitry of one or more photoelectric conversion pixels, or any other component of prior art image sensors) for subsequent CP testing and package bonding connections. In one embodiment, one or more solder pads of the image sensor can be used to couple the image sensor to one or more microcontrollers or processors (e.g., for image sensor operation), memory (e.g., for storing image data), or other components.

[0080] Since the formed solder pads are used for both CP testing and packaging bonding, and the CP testing requires a large number of solder pads, the solder pad trench 11 formed in this step also includes several second solder pad trenches 111 (e.g., Figure 4 As shown in the figure, the planar area of ​​the first pad trench 110 is larger than the planar area of ​​the second pad trench 111. The second pad formed by the second pad trench 111 can be used only for CP testing, while the first pad formed by the first pad trench 110 can be reused for CP testing and package bonding.

[0081] In some implementations, the first solder pad trench 110 formed on the side near the light-shielding pixel area 120 may be formed on the opposite back side of the light-shielding pixel area 120 away from the light-transmitting pixel area, or it may be formed in a region offset horizontally from the light-transmitting pixel area toward the peripheral circuit area at the edge of the light-shielding pixel area 120 away from the light-transmitting pixel area. A detailed description will follow in conjunction with the formed first solder pad structure.

[0082] As an example, such as Figure 3 As shown, before forming the plurality of solder pad trenches 11, the process includes a step of forming the desired trench isolation structure 16 from the back side of the pixel region 100 and the peripheral region 103 inward. The depth of the trench isolation structure 16 is specifically set according to different regions. For example, the trench isolation structure 16 formed in the pixel region 100 is shallower and is a shallow trench isolation structure between pixels, while the trench isolation structure 16 formed in the peripheral region 103 is deeper and is a deep trench isolation structure outside the pixel.

[0083] like Figure 7 As shown, step S3 is then performed, where a grid material layer 12 is deposited on the substrate 10. In this implementation, the grid material layer 12 is deposited on the back side of the substrate 10.

[0084] The grid material layer 12 can be deposited using existing conventional deposition processes, such as CVD, PVD, ALD, electroplating, etc. The material of the grid material layer 12 is generally chosen to be a conductive and opaque material, such as tungsten.

[0085] As an example, such as Figure 6 As shown, before depositing the grid material layer 12, a step of forming a plurality of electrical connection trenches 17 from the surface of the peripheral region 103 inward is included. In this implementation, a plurality of electrical connection trenches 17 are formed from the back side of the peripheral region 103 inward. At this time, when depositing the grid material layer 12, the grid material layer 12 is also deposited simultaneously on the sidewalls and bottom walls of the electrical connection trenches 17. After the conductive grid material layer 12 is deposited in the electrical connection trenches 17, the electrical connection trenches 17 are used to realize the electrical interconnection or electrical lead-out of transistors and the like required between the pixel region 100 and the peripheral region 103, and can be interconnected by wiring based on the existing interconnection structure layer in the image sensor. For example, the electrical connection trenches 17 can be TSV trenches, and interconnection between stacked chips can be realized based on TSV and its internal conductive layer.

[0086] like Figure 8 and Figure 9 As shown, step S4 is then performed, where the pad material is used to fill the pad trench 11 to form a pad 13; wherein, the pad 13 includes a first pad 130 formed at the first pad trench 110, and the first pad 130 includes a CP test area 133 and a bonding area 132 (e.g., ...). Figure 9 (As shown). That is, the first solder pad 130 serves as a reused solder pad, and the CP test area 133 is used during CP testing. During CP testing, the test probe is inserted into the CP test area 133 to achieve electrical contact for CP testing. This process will form probe marks on the surface of the CP test area 133. The bonding area 132 is used for wire connection during the packaging process. Since this area does not contact the probe, no probe marks are generated, thus ensuring the wire bonding yield during packaging. The area settings of the CP test area 133 and the bonding area 132 of the first solder pad 130 can be configured differently according to actual conditions, for example... Figure 9 The center can be set as a left-right area, or it can be set as a top-bottom area, etc.

[0087] As an example, when the pad groove 11 also includes a second pad groove 111, after the pad material is filled in this step, the second pad groove 111 is formed into a second pad 131. Since CP testing requires a large number of pads, the second pad 131 is generally used as a CP testing pad. During CP testing, the test probe not only penetrates the CP testing area 133 but also penetrates the surface of the second pad 131 to achieve electrical contact for CP testing, forming probe marks on the surface of the second pad 131.

[0088] like Figure 10As shown, the final step, S5, is performed to pattern the grille material layer 12 to form the desired grille 14 in the light-transmitting pixel area 101 and to form a light-shielding shielding layer in the light-shielding pixel area 102. For example, in this implementation, the light-shielding shielding layer is also the light-shielding shielding layer 15. During this process, the metal patterning process for forming the electrical connection trench 17 can also be performed simultaneously.

[0089] For example, the grid material layer 12 can be patterned using photolithography etching.

[0090] As an example, such as Figure 11 As shown, step S5 is followed by a step of forming a passivation layer 18 on the front side of the resulting structure. The passivation layer 18 can be prepared using existing conventional passivation layer preparation processes, such as CVD, PVD, ALD, electrochemical processes, or spin coating processes. The passivation layer 18 is generally made of an insulating material, such as silicon oxide, silicon nitride, aluminum oxide, or other high-k materials. In this embodiment, the passivation layer 18 is selected as a silicon oxide layer or a silicon nitride layer, with a thickness generally selected to be 80 Å to 200 Å, for example, 100 Å, 120 Å, 150 Å, or 180 Å. The passivation layer 18 can be a material layer formed on the surface of the pad 13 during the image sensor fabrication process. For example, it can be an insulating layer on the light-shielding shielding layer 15 of the pixel region 100, or it can be other material layers formed on the surface of the pad 13 during the process that need to be removed.

[0091] As an example, after the passivation layer 18 is formed, a CP test step is also included; wherein, before the CP test, there is a step of opening the PAD to perform the CP test. In this example, the step of opening the PAD includes the step of opening the passivation layer 18 to perform the test. The CP test can be performed before packaging. In the example of this application, during the CP test, the test probe is inserted into the CP test area 132 of the first solder pad 130 to achieve electrical contact for the CP test. Of course, when the solder pad 13 also includes a second solder pad 131, the test probe will also be inserted into the second solder pad 131 to achieve electrical contact for the CP test and leave probe marks in the corresponding area.

[0092] As a further example, such as Figure 19 and Figure 20 As shown, the fabrication method further includes the step of forming a filter array 22 on the front side of the pixel region 100. Figure 19 As shown, during the fabrication of the filter array 22, because the chip is surrounded by solder pads, and an insulating layer is formed in the solder pads and electrical connection trenches before fabricating the filter array 22, the upper surface of this insulating layer is higher than the upper surface of the pixel area. During the subsequent spin coating process for developing the filter material layer, the insulating layer will act as a barrier, leading to... Figures 17 to 19The developer residue 24 shown remains at the bottom or top of different filter layers, resulting in stripe patterns in the image sensor imaging.

[0093] The advantages of this implementation are illustrated below with a specific example of forming a filter array:

[0094] like Figure 12 and Figure 13 As shown, an insulating layer 19 is first formed on the solder pad 13, and the upper surface of the insulating layer 19 is higher than the upper surface of the pixel region 100. Of course, when the pixel region 100 is also provided with an electrical connection trench 17, the insulating layer 19 also needs to fill the corresponding electrical connection trench 17 to the same height as the insulating layer 19 on the solder pad 13.

[0095] like Figure 14 and Figure 15 As shown, a filter material layer 20 of the desired light-transmitting color is then coated on the front side of the substrate. Here, the filter material layer 20 is selected from materials that can be deformed by exposure.

[0096] like Figure 16 As shown, the filter material layer 20 at the desired location is then exposed based on the mask 23 to obtain the filter layer 21 with the desired light transmission color.

[0097] like Figure 17 As shown, the final development removes the unexposed filter material layer 20. During this development and spin coating process, the insulating layer 19 and the material corresponding to the pad areas act as a barrier, leaving various residues 24 (including developer residue and material from the filter material layer, etc.) on the bottom surface of other areas where filter layers need to be formed. Similarly, as... Figure 18 As shown, during the development and spin coating process of the filter layer in the middle of the filter array, the insulating layer has a blocking effect, causing residue 24 to remain on the bottom surface of another filter layer area and the upper surface of the filter layer 21 already formed on the left; in addition, as Figure 19 As shown, during the development and spin coating process of the filter layer on the right side of the filter array, the insulating layer acts as a barrier, causing residue 24 to remain on the upper surface of the other two formed filter layers 21. This residue can be formed from filter layers of different colors prepared using different steps.

[0098] In this embodiment, the larger first solder pad 130 of the solder pads 13 is positioned on the side closer to the light-shielding pixel area. Because the first solder pad 130 has a larger planar size, the obstruction caused by the insulating layer in the solder pad area is greater during the development and spin coating process of forming the filter array. However, due to the isolation effect of the light-shielding pixel area, the residue 24 will remain more on the upper and lower surfaces of the filter array in the light-shielding pixel area, and the residue 24 in the light-shielding pixel area will not affect the stripe effect on the imaging of the light-transmitting pixel area. On the other hand, since the first solder pad 130 is positioned on the side closer to the light-shielding pixel area, other sides may not have solder pads or may have smaller second solder pads depending on actual needs. Therefore, during the development and spin coating process of forming the filter array, the residue 24 can be effectively discharged, further reducing the amount of residue 24 remaining on the upper and lower surfaces of the filter array (e.g., Figure 20 (as shown), thereby reducing stripe patterns generated in image sensor imaging. Of course, in different implementations, the first pad 130 and / or the second pad 131 can also be arranged in other areas around the pixel area as needed, but at least part of the first pad 130 is arranged on the side closer to the light-shielding pixel area 102 to improve glare problems in the image sensor.

[0099] As a specific example, such as Figure 20 As shown, the filter array 22 includes an array formed by a red light filter layer 210, an array formed by a green light filter layer 211, and an array formed by a blue light filter layer 212. Furthermore, at least two of the red light filter layer 210, the green light filter layer 211, and the blue light filter layer 212 are prepared using different process steps.

[0100] Example 2

[0101] This embodiment provides an image sensor, which can be prepared using the preparation method of Embodiment 1. The beneficial effects that can be achieved by the preparation method of Embodiment 1 will not be repeated here.

[0102] like Figure 1 , Figure 11 and Figure 21 As shown, the image sensor includes:

[0103] A substrate 10 having a front and a back side, the substrate 10 including a pixel region 100 and a peripheral region 103, the pixel region 100 including at least a plurality of photoelectric conversion pixels, the peripheral region 103 being disposed on the outer periphery of the pixel region 100; wherein, the pixel region 100 includes a light-transmitting pixel region 101 and a light-shielding pixel region 102, and the light-shielding pixel region 102 being disposed on at least one side outside the light-transmitting pixel region 101;

[0104] A plurality of solder pads 13 are disposed on the outer periphery of the peripheral region 103 and arranged along the extending direction of the outer periphery; wherein, the solder pads 13 include a first solder pad 130, the first solder pad 130 being formed at least on one side near the light-shielding pixel region 102, and the first solder pad 130 including a CP test region 132 and a bonding region 133 (e.g., Figure 9 (as shown);

[0105] A light-shielding shielding layer 15 is disposed on the light-shielding pixel area 102.

[0106] In the structure of the image sensor, the pixel region 100 includes multiple photoelectric conversion pixels, and generally also includes pixel circuits corresponding to the photoelectric conversion pixels, depending on actual needs. The peripheral region 103 is generally provided with signal lines connecting the photoelectric conversion pixels and external devices, peripheral circuits connected to the photoelectric conversion pixels, and / or pads (PADs) 13.

[0107] The pads 13 are used to provide electrical contact with one or more components of the image sensor (e.g., the associated control circuitry of one or more photoelectric conversion pixels, or any other component of a prior art image sensor), for CP testing and package bonding connections, etc. In one embodiment, one or more pads 13 of the image sensor can be used to couple the image sensor to one or more microcontrollers or processors (e.g., for operation of the image sensor), memory (e.g., for storing image data), or others.

[0108] like Figure 11 As shown, as an example, the image sensor also includes a trench isolation structure 16 and an electrical connection trench 17; wherein, the trench isolation structure 16 extends inward from the surface of the pixel region 100 and the peripheral region 103, and the electrical connection trench 17 extends inward from the surface of the peripheral region 103. The depth of the trench isolation structure 16 is specifically set according to different regions; for example, the trench isolation structure 16 formed in the pixel region 100 is shallower, which is a shallow trench isolation structure between pixels, and the trench isolation structure 16 formed in the peripheral region 103 is deeper, which is a deep trench isolation structure outside pixels. The sidewalls and bottom of the electrical connection trench 17 are covered with conductive material to make it conductive. The conductive electrical connection trench 17 is used to realize the electrical interconnection or electrical lead-out of transistors and the like required between the pixel region 100 and the peripheral region 103, and can be interconnected by wiring based on the existing interconnection structure layer in the image sensor. For example, the electrical connection trench 17 can be a TSV trench, which can realize the interconnection between stacked chips based on the TSV and its internal conductive layer.

[0109] For example, the first solder pad 130 is formed on the side close to the light-shielding pixel area 120, or the first solder pad 130 can be formed on the back side of the light-shielding pixel area 120 opposite to the light-transmitting pixel area, such as... Figure 25 As shown, it can also be a region formed on the edge of the light-blocking pixel area 120 away from the light-transmitting pixel area, offset horizontally towards the peripheral circuit area from the light-transmitting pixel area, such as... Figure 26 As shown, of course, it is also possible that both of the above regions form the first solder pad 130.

[0110] like Figures 23 to 26 As shown, since the CP test requires a large number of solder pads, in addition to setting the first solder pad 130 in the solder pad 13, several second solder pads 131 can also be set. The second solder pads 131 are used for the CP test. The planar area of ​​the first solder pad 130 is larger than the planar area of ​​the second solder pad 131.

[0111] Preferably, the planar area of ​​the first solder pad 130 is 2 to 5 times the planar area of ​​the second solder pad 131, such as 2.25 times, 3 times, 3.5 times, etc. Furthermore, as mentioned above, the size range of the first solder pad is (80-100) μm × (140-180) μm, and correspondingly, the size range of the second solder pad is (70-90) μm × (70-90) μm. For example, the cross-sectional shape of the first solder pad is rectangular, and the second solder pad can be square, with dimensions such as 80 μm × 80 μm, 85 μm × 85 μm, etc.

[0112] Depending on actual needs, the light-shielding pixel area 102 can be disposed on one side, both sides, or even more sides outside the light-transmitting pixel area 101, for example... Figure 21 It is located on one side outside the light-transmitting pixel area 101. Figure 22 The light-transmitting pixel areas 101 are located on opposite sides of each other. Additionally, the first solder pad 130 is located near the light-shielding pixel area 102. In practice, when the number of first solder pads 130 is small, they can be arranged on the outer periphery of one side of the outer area, such as... Figure 21 As shown; when the number of first solder pads 130 is large, they can be arranged on both sides or multiple layers of the outer perimeter of the outer area, such as... Figure 22 and Figure 26 As shown, the light-shielding pixel area 102 is disposed on opposite sides outside the light-transmitting pixel area 101, and the first solder pad 130 is disposed on the opposite sides outside the light-transmitting pixel area 101.

[0113] like Figure 25As shown, when the solder pad 13 further includes the second solder pad 131, a portion of the second solder pad 131 is disposed on the same side as the first solder pad 130 and arranged along the extending direction of the outer periphery; another portion of the second solder pad 131 is disposed on other outer peripheries of the peripheral region 103. This configuration is suitable when the number of the first solder pad 130 is small.

[0114] like Figure 23 and Figure 24 As shown, when the solder pad 13 further includes the second solder pad 131, and the number of the first solder pads 130 is large, and the number of the second solder pads 131 is also large, all the second solder pads 131 can be placed on other outer peripheries outside the outer periphery of the outer area 103 where the first solder pads 130 are located. Specifically, depending on the number of the second solder pads 131, they can be placed on one side or both sides of other outer peripheries (e.g., Figure 24 That is, the two sides or three sides of the other outer perimeter (such as...). Figure 23 That is, on the other three sides of the outer periphery). Furthermore, the four ends of the outer periphery of the outer region 103 can all be set as the second solder pad 131, which makes it easier for residues to be discharged during the developing and spinning process of forming the filter array.

[0115] like Figures 27 to 31 As shown, the first bonding pad 130 in the image sensor can also be arranged in other ways, depending on the requirements, such as... Figure 31 As shown, the image sensor only has a first bonding pad 130, which is arranged around the pixel area. Of course, a second bonding pad 131 can also be further provided, such as... Figure 27 As shown, placing the first solder pad at the corner of the corresponding pixel area outside the light-shielding pixel area improves glare and also helps to reduce adhesive residue. Figure 28 As shown, the first bonding pad 130 can be arranged outside the light-shielding pixel area and on one adjacent side, while the second bonding pads are arranged on the other two sides, as shown. Figure 29 As shown, the first and second solder pads can also be arranged alternately, such as... Figure 30 As shown, the second pad can be placed in the area corresponding to the corner of the pixel area, which is beneficial for the placement of the first pad and the utilization of space.

[0116] As another better example, such as Figure 32 and Figure 33As shown, the cross-sections of the first solder pad 130 and the second solder pad 131 are regular shapes, for example, both are rectangles. When all the second solder pads 131 are located on other outer peripheries outside the outer periphery of the outer area 103 where the first solder pad 130 is located, the cross-sections of the first solder pad and the second solder pad are regular shapes. The center distance between two adjacent second solder pads is equal to the center distance between two adjacent first solder pads, that is, the center distance between two adjacent second solder pads is L2; ​​the center distance between two adjacent first solder pads is L1, L1 equals L2. Since the size of the first solder pad facing the pixel area is greater than the size of the second solder pad facing the pixel area, the gap formed by the adjacent second solder pads is greater than the gap formed by the adjacent first solder pads, which is beneficial for glue spinning.

[0117] This embodiment also provides an electronic device, including the image sensor described in Embodiment 2. The electronic device can be a security monitoring device, vehicle electronics, a mobile phone camera, a machine vision device, etc., and the image sensor based on this invention can acquire high-quality image information.

[0118] In summary, the image sensor and its fabrication method of the present invention utilize the location of the light-shielding pixel area to set the first bonding pad. By placing the first bonding pad, which serves both CP testing and packaging bonding purposes, at least on the side close to the light-shielding pixel area during the fabrication of the bonding pad in the peripheral area, the first bonding pad can be separated from the light-transmitting pixel area. This ensures that the reflected light from the first bonding pad almost entirely falls on the light-shielding pixel area, reducing or even eliminating reflected light from entering the light-transmitting pixel area, thereby reducing glare and improving the imaging quality of the image sensor. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial applicability.

[0119] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An image sensor, characterized in that, The image sensor includes: A substrate having a front and a back side, the substrate including a pixel region and a peripheral region, the pixel region including at least a plurality of photoelectric conversion pixels, the peripheral region being disposed on the outer periphery of the pixel region; wherein, the pixel region includes a light-transmitting pixel region and a light-shielding pixel region, the light-shielding pixel region being disposed on at least one side outside the light-transmitting pixel region; A plurality of solder pads are disposed on the outer periphery of the peripheral region and arranged along the extending direction of the outer periphery; wherein, the solder pads include a first solder pad, which is formed on the side close to the light-shielding pixel area, and the first solder pad includes a CP test area and a bonding area; A light-shielding shielding layer is disposed on the light-shielding pixel area.

2. The image sensor according to claim 1, characterized in that: It also includes a trench isolation structure and an electrical connection trench; wherein the trench isolation structure extends inward from the surface of the pixel region and the peripheral region, and the electrical connection trench extends inward from the surface of the peripheral region.

3. The image sensor according to claim 1, characterized in that: The solder pad further includes a second solder pad, and the planar area of ​​the first solder pad is greater than the planar area of ​​the second solder pad.

4. The image sensor according to claim 3, characterized in that: The planar area of ​​the first solder pad is 2-5 times that of the planar area of ​​the second solder pad; and / or, the size range of the first solder pad is (80-100) μm × (140-180) μm, and the size range of the second solder pad is (70-90) μm × (70-90) μm; and / or, the cross-sectional shape of the first solder pad is rectangular, and the cross-sectional shape of the second solder pad is square; and / or, the cross-sections of the first solder pad and the second solder pad are regular shapes, the center-to-center distance between two adjacent second solder pads is equal to the center-to-center distance between two adjacent first solder pads, and the size of the first solder pad facing the pixel region is greater than the size of the second solder pad facing the pixel region.

5. The image sensor according to claim 3, characterized in that: A portion of the second solder pads are disposed on the same side as the first solder pads and arranged along the extension direction of the outer periphery; another portion of the second solder pads are disposed on other outer peripheries of the peripheral region, or all of the second solder pads are disposed on other outer peripheries outside the outer periphery of the peripheral region where the first solder pads are located.

6. The image sensor according to claim 5, characterized in that: The four ends of the outer perimeter of the peripheral area are all configured as the second solder pads.

7. The image sensor according to claim 3, characterized in that: The first solder pad and the second solder pad are alternately arranged; or, the first solder pad is arranged at the corner of the pixel area, and the other peripheral areas are arranged as the second solder pad; or, the first solder pad is arranged on the adjacent side of the pixel area, and the other adjacent sides are arranged as the second solder pad; or, the first solder pad is arranged on the opposite side of the pixel area, and the second solder pad is arranged on the other opposite side of the pixel area.

8. The image sensor according to claim 1, characterized in that: The light-shielding pixel area is located on opposite sides outside the light-transmitting pixel area; and / or, the solder pads are all first solder pads, located around the pixel area.

9. An electronic device, characterized in that, Including the image sensor as described in any one of claims 1 to 8.

Images