Photoelectric sensor structure and forming method thereof

Abstract

The invention discloses a photoelectric sensor structure and a forming method thereof, the structure comprises a first substrate, the first substrate comprises a plurality of adjacent photosensitive areas and isolation areas surrounding the photosensitive areas, the plurality of photosensitive areas have the same pattern projected on the surface of the first substrate, and each photosensitive area is adjacent to at least two photosensitive areas; each photosensitive area comprises at least two contour lines parallel to the contour of the adjacent photosensitive area, the two contour lines intersect, and the included angle between the two intersecting contour lines is an obtuse angle; a photosensitive doped region located in the photosensitive region; and an isolation structure located in the isolation region. In the photoelectric sensor structure, the number of the contour lines intersected at the same point is less than four, so that the number of the contour lines at the intersection points is reduced, the etching directions passing through the intersection points are reduced, the influence of critical dimension gradual change at the intersection points is further reduced, complete etching of the bottom of an isolation area is realized, electric leakage and optical crosstalk are avoided, and the reliability of the photoelectric sensor is improved. Therefore, the process difficulty is reduced, and the photon detection efficiency of the photoelectric sensor is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a photoelectric sensor structure and a forming method thereof. Background Art

[0002] In the chip manufacturing of direct imaging ranging sensors, the backside illumination sensor (BSI) process structure is usually adopted to improve the comprehensive optical performance. After the silicon wafer is thinned, the logic wafer (Logic Wafer) and the pixel wafer (Pixel Wafer) are bonded together, and the light is injected from the back to increase the photosensitive area of ​​the photoelectric element. In order to prevent photoelectric crosstalk between adjacent pixels, the deep trench isolation (DTI) structure is usually selected to completely isolate adjacent pixels.

[0003] The existing DTI array is square in shape, and the intersections between adjacent DTIs are crosses. When etching DTI, it is necessary to completely etch in four directions, which has high requirements for the etching process. In addition, the bottom of the cross intersection of DTI is prone to not being completely etched, resulting in leakage and optical crosstalk. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a photoelectric sensor structure and a method for forming the same, so as to improve the photon detection efficiency of the photoelectric sensor and reduce the process difficulty.

[0005] In order to solve the above technical problems, the technical solution of the present invention provides a photoelectric sensor structure, including: a first substrate, the first substrate including a plurality of adjacent photosensitive areas, and an isolation area surrounding each photosensitive area, the plurality of photosensitive areas projected onto the surface of the first substrate have the same pattern, each of the photosensitive areas is adjacent to at least two photosensitive areas, and each photosensitive area includes at least two contour lines parallel to the contours of adjacent photosensitive areas, and the two contour lines intersect, and the angle between the two intersecting contour lines is an obtuse angle; a photosensitive doped area located in the photosensitive area; and an isolation structure located in the isolation area.

[0006] Optionally, the contour line is a straight line or a curve.

[0007] Optionally, when the contour line is a curve, the angle is the angle between tangents of the two contour lines at the intersection point.

[0008] Optionally, the shape of the photosensitive area includes an axisymmetric figure.

[0009] Optionally, the shape of the photosensitive area includes a quadrilateral and a hexagon.

[0010] Optionally, the curve is "S" shaped.

[0011] Optionally, the photosensor structure further includes: a second groove or a fourth groove located in the first substrate; a charge collection structure located in the second groove or the fourth groove, and the charge collection structure is adjacent to the plurality of photosensitive areas.

[0012] Optionally, the charge collection structure includes: a first shielding layer located in the second trench and the fourth trench.

[0013] Optionally, the material of the first shielding layer includes aluminum and tungsten; and the thickness of the charge collection structure ranges from 0 μm to 4 μm.

[0014] Optionally, the isolation structure includes: a first trench located in the first substrate; a dielectric layer located on the inner wall surface of the first trench, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

[0015] Optionally, the isolation structure includes: a third trench located in the first substrate; a dielectric layer located on the inner wall surface of the third trench, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

[0016] Optionally, the material of the second shielding layer includes aluminum and tungsten; the material of the insulating layer includes silicon oxide; the material of the dielectric layer includes high-K dielectric; and the thickness of the isolation structure ranges from 2 μm to 10 μm.

[0017] Optionally, the photoelectric sensor structure further includes: a second substrate bonded to the first substrate, the second substrate having a logic circuit therein; the first substrate includes a first surface and a second surface opposite to each other, the first surface being the surface bonded toward the second substrate.

[0018] Optionally, the photoelectric sensor structure further includes: a device layer located on the surface of the first side, the device layer including: a first electrical interconnection structure, the first electrical interconnection structure being electrically connected to one or more of the photosensitive doped region, the isolation structure, the charge collection structure and the logic circuit.

[0019] Optionally, the device layer further includes: an interlayer dielectric layer located on the surface of the first side, and the interlayer dielectric layer surrounds the first electrical interconnection structure.

[0020] Correspondingly, the technical solution of the present invention also provides a method for forming a photoelectric sensor structure, including: providing a first substrate, the first substrate including a plurality of adjacent photosensitive areas, and an isolation area surrounding each photosensitive area, the plurality of photosensitive areas projected onto the surface of the first substrate have the same pattern, each of the photosensitive areas is adjacent to at least two photosensitive areas, and each photosensitive area includes at least two contour lines parallel to the contours of adjacent photosensitive areas, and the two contour lines intersect, and the angle between the two intersecting contour lines is an obtuse angle; forming a photosensitive doping area in the photosensitive area; and forming an isolation structure in the isolation area.

[0021] Optionally, the method for forming the photoelectric sensor structure further includes: forming a charge collection structure in the first substrate, and the charge collection structure is adjacent to the plurality of photosensitive regions.

[0022] Optionally, the charge collection structure and the isolation structure are interconnected, and the method for forming the charge collection structure and the isolation structure includes: forming a first mask layer on the surface of the second surface, the first mask exposing a portion of the surface of the second surface; using the first mask layer as a mask, etching the second surface to form a first groove in the first substrate; forming an isolation structure in the first groove; forming a second mask layer on the surface of the second surface, the second mask exposing a portion of the surface of the second surface; using the second mask layer as a mask, etching the second surface to form a second groove in the first substrate; forming a charge collection structure in the second groove; the charge collection structure includes: a first shielding layer located on the inner wall surface of the second groove; the isolation structure includes: a first groove located in the first substrate; a dielectric layer located on the inner wall surface of the first groove, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

[0023] Optionally, the charge collection structure and the isolation structure are formed in different grooves, and the method for forming the isolation structure and the charge collection structure includes: forming a third mask layer on the surface of the second surface, the third mask exposing a portion of the surface of the second surface; using the third mask layer as a mask, etching the second surface to form a third groove in the first substrate; forming an isolation structure in the third groove; forming a fourth mask layer on the surface of the second surface, the fourth mask exposing a portion of the surface of the second surface; using the fourth mask layer as a mask, etching the second surface to form a fourth groove in the first substrate; forming a charge collection structure in the fourth groove; the charge collection structure includes: a first shielding layer located on the inner wall surface of the fourth groove; the isolation structure includes: a dielectric layer located on the inner wall surface of the third groove, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

[0024] Optionally, the method for forming the photoelectric sensor structure also includes: before forming the isolation structure and the charge collection structure, bonding the first surface to form a second substrate, the second substrate including a logic circuit, the first surface being a surface facing the second substrate, and the first substrate including a first surface and a second surface relative to each other.

[0025] Optionally, the method for forming the photoelectric sensor structure also includes: before bonding the second substrate, forming a device layer on the surface of the first surface, the device layer including a first electrical interconnection structure and an interlayer dielectric layer located on the surface of the first surface, and the interlayer dielectric layer surrounds the first electrical interconnection structure.

[0026] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0027] In the photoelectric sensor structure provided in the technical solution of the present invention, the graphics of each photosensitive area projected on the surface of the first substrate are the same, and each of the photosensitive areas is adjacent to at least two photosensitive areas, and the angle formed by the intersection of two contour lines between two adjacent photosensitive areas is an obtuse angle. Therefore, the number of adjacent photosensitive areas surrounding the same point is less than four, that is, there are less than four contour lines intersecting at the same point, which reduces the number of contour lines at the intersection point, reduces the etching direction passing through the intersection point, and further reduces the influence of the gradual change of the critical dimension at the intersection point, so that the bottom of the isolation area is completely etched, avoiding leakage and optical crosstalk, thereby reducing the process difficulty and improving the photon detection efficiency of the photoelectric sensor.

[0028] Furthermore, in the technical solution of the present invention, by forming a charge collection structure on the surface of the first substrate adjacent to the photosensitive area, and the charge collection structure and the isolation structure are formed in the same groove, there is no need to form openings and electrical interconnection structures on the longitudinal surfaces of the charge collection structure and the isolation structure, so that the charge collection structure and the isolation structure form an integrated structure, thereby reducing the wafer area, volume and number of mask layers, and reducing the process difficulty.

[0029] In the method for forming a photoelectric sensor structure provided in the technical solution of the present invention, photosensitive areas with the same pattern projected onto the surface of the first substrate are formed on the surface of the first substrate, and each of the photosensitive areas is adjacent to at least two photosensitive areas, and the angle formed by the intersection of two contour lines between two adjacent photosensitive areas is an obtuse angle. Therefore, the number of adjacent photosensitive areas surrounding the same point is less than four, that is, the number of contour lines intersecting at the same point is less than four, which reduces the number of contour lines at the intersection point, reduces the etching direction passing through the intersection point, and further reduces the influence of the gradual change of the critical dimension at the intersection point, so that the bottom of the isolation area is completely etched, and leakage and optical crosstalk are avoided, thereby reducing the process difficulty and improving the photon detection efficiency of the photoelectric sensor.

[0030] Furthermore, in the technical solution of the present invention, by forming an isolation structure and a charge collection structure that are interconnected on the surface of the second surface, there is no need to form openings on the surfaces of the isolation structure and the charge collection structure, thereby reducing the number of mask layers and reducing the process cost. Moreover, the materials of the isolation structure and the charge collection structure are both tungsten or aluminum, and there is no need to form an interconnection structure on the surfaces of the charge collection structure and the isolation structure, so that electrical connection and charge transfer between the isolation structure and the charge collection structure can be achieved, thereby reducing the wafer area, volume and the number of mask layers and reducing the process difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of a photoelectric sensor;

[0032] Figures 2 to 13 is a structural schematic diagram of a formation process of a photoelectric sensor in one embodiment of the present invention;

[0033] Figures 14 to 16 It is a structural schematic diagram of the formation process of a photoelectric sensor in another embodiment of the present invention. DETAILED DESCRIPTION

[0034] It should be noted that the terms “surface” and “on” in this specification are used to describe relative positional relationships in space and are not limited to direct contact.

[0035] As described in the background art, it is necessary to improve the photon detection efficiency of the photoelectric sensor and reduce the process difficulty. Now, an analysis and explanation will be given in conjunction with a specific embodiment.

[0036] Figure 1 It is a structural diagram of a photoelectric sensor.

[0037] Please refer to Figure 1 , Figure 1 The schematic diagram of the top view of the structure is as follows. The method for forming the photoelectric sensor includes: a substrate 100, wherein the substrate 100 includes a plurality of photosensitive regions 101 and a plurality of isolation regions 102 surrounding the photosensitive regions 101, wherein the photosensitive regions 101 are arranged in an array along a first direction X and a second direction Y, wherein the first direction X and the second direction Y are perpendicular to each other; a photosensitive doped region (not shown in the figure) located in the photosensitive region 101; and an isolation structure (not shown in the figure) located in the isolation region 102.

[0038] In the above scheme, the number of isolation areas intersecting at the same point is 4. As the number of isolation areas intersecting at the same point increases, the etching difficulty at the intersection increases, and the critical dimension (CD) gradient is more likely to occur, resulting in the bottom of the isolation area not being completely etched, which in turn causes leakage and optical crosstalk, affecting the performance of the photoelectric sensor.

[0039] In order to solve the above technical problems, the technical solution of the present invention provides a photoelectric sensor structure and a formation method, wherein the patterns of each photosensitive area projected on the surface of the first substrate are the same, and each of the photosensitive areas is adjacent to at least two photosensitive areas, and the angle formed by the intersection of two contour lines between two adjacent photosensitive areas is an obtuse angle. Therefore, the number of adjacent photosensitive areas surrounding the same point is less than four, that is, there are less than four contour lines intersecting at the same point, which reduces the number of contour lines at the intersection point, reduces the etching direction passing through the intersection point, and further reduces the influence of the key dimension gradient at the intersection point, so as to achieve complete etching of the bottom of the isolation area, avoid leakage and optical crosstalk, thereby reducing the process difficulty and improving the photon detection efficiency of the photoelectric sensor.

[0040] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0041] Figures 2 to 10 It is a structural schematic diagram of the formation process of the photoelectric sensor in one embodiment of the present invention.

[0042] Please refer to Figure 2 as well as Figure 5 , Figure 2 This is a top view of the structure. Figure 5 yes Figure 2 In the cross-sectional schematic diagram along line AA1, a first substrate 200 is provided, wherein the first substrate 200 includes a plurality of adjacent photosensitive areas I and an isolation area II surrounding each photosensitive area I, wherein the plurality of photosensitive areas I are projected onto the surface of the first substrate 200 with the same pattern, wherein each of the photosensitive areas I is adjacent to at least two photosensitive areas I, and each of the photosensitive areas I includes at least two contour lines 201 parallel to the contours of the adjacent photosensitive areas I, and the two contour lines 201 intersect, and an angle 202 between the two intersecting contour lines 201 is an obtuse angle; a photosensitive doping area 203 is formed in the photosensitive area I.

[0043] In this embodiment, the material of the first substrate 200 includes silicon, and the doping type of the first substrate 200 is P-type doping.

[0044] In other embodiments, the material of the first substrate 200 includes silicon carbide, silicon germanium, a multinary semiconductor material composed of group III-V elements, silicon on insulator (SOI) or germanium on insulator (GOI). Among them, the multinary semiconductor material composed of group III-V elements includes InP, GaAs, GaP, InAs, InSb, InGaAs or InGaAsP.

[0045] In this embodiment, the contour line 201 is a straight line and / or a curve.

[0046] In this embodiment, when the contour line 201 is a curve, the angle 202 is the tangent angle 202 of the two contour lines 201 at the intersection point, wherein the curve is an “S” shape.

[0047] Please refer to Figure 4 , the “S” shape is a zipper type.

[0048] Please refer to Figure 2 as well as Figure 3 In this embodiment, the shape of the photosensitive area I includes an axially symmetrical figure. Specifically, the shape of the photosensitive area I includes a hexagon and a quadrilateral. The present invention is not limited to this. Other shapes of the photosensitive area I are within the protection scope of the technical solution of the present invention.

[0049] In this embodiment, the photosensitive region I has a photosensitive doping region 203, and the first surface a exposes the photosensitive doping region 203. The doping type of the photosensitive doping region 203 is N-type doping, and the doping ions in the photosensitive doping region 203 include: arsenic, boron, carbon, boron fluoride, fluorine, phosphorus, nitrogen, aluminum, germanium or antimony.

[0050] In this embodiment, the photosensitive doping region 203 is used to achieve photoelectric conversion.

[0051] In other implementations not shown in the figures, the photoelectric sensor further includes a testing area.

[0052] In this embodiment, Figure 5 As shown, the first substrate 200 further has a first surface a and a second surface b opposite to the first surface a, and light is incident on the photoelectric sensor from the second surface b.

[0053] Please refer to Figure 6 , Figure 6 and Figure 5 The viewing direction is consistent, and a device layer is formed on the surface of the first surface a. The device layer includes a first electrical interconnection structure and an interlayer dielectric layer located on the surface of the first surface a. The interlayer dielectric layer surrounds the first electrical interconnection structure.

[0054] In this embodiment, the interlayer dielectric layer includes a first interlayer dielectric layer 204 located on the first surface a.

[0055] In this embodiment, the first electrical interconnection structure includes: a first interconnection member 205 located on the surface of the first surface a and a first conductive layer 208 located in the first interlayer dielectric layer 204, the first interconnection member 205 includes several overlapping first interconnection layers 206 and several first conductive plugs 207 located between adjacent first interconnection layers 206 and between the first interconnection layer 206 and the first substrate 200.

[0056] In this embodiment, the method for forming the first interlayer dielectric layer 204 and the first electrical interconnection structure includes: forming an initial first interlayer dielectric layer (not shown in the figure) on the surface of the first surface a, etching the initial first interlayer dielectric layer (not shown in the figure) to form a first opening (not shown in the figure), a second opening (not shown in the figure) and the first interlayer dielectric layer 204, wherein the first opening (not shown in the figure) exposes the surface of the first substrate 200; forming a plurality of overlapping first interconnection layers 206 and a plurality of first conductive plugs 207 located between adjacent first interconnection layers 206 and between the first interconnection layer 206 and the first substrate 200 in the first opening (not shown in the figure), and forming a first conductive layer 208 in the second opening (not shown in the figure).

[0057] In this embodiment, the number of the first conductive plugs 207 ranges from 1 to 5, and specifically, there are two first conductive plugs 207 ; the material of the first interconnect layer 206 and the first conductive layer 208 is a conductive metal material, and specifically, the metal material is aluminum.

[0058] In this embodiment, the interlayer dielectric layer further includes a second interlayer dielectric layer 213 located on the surface of the first interlayer dielectric layer 204 .

[0059] In this embodiment, the first electrical interconnection structure further includes: a second interconnection 209 and a second conductive layer 212 located in the second interlayer dielectric layer 213 , wherein the second interconnection 209 includes a plurality of overlapping second interconnection layers 210 and a plurality of second conductive plugs 211 located between adjacent second interconnection layers 210 .

[0060] Please refer to Figure 7 , Figure 7 and Figure 6 In the same direction of the view, the method for forming the second interlayer dielectric layer 213 and the first electrical interconnection structure includes: bonding to form an initialized second interlayer dielectric layer (not shown in the figure) on the surface of the first interlayer dielectric layer 204, etching the initial second interlayer dielectric layer (not shown in the figure) to form a third opening (not shown in the figure), a fourth opening (not shown in the figure) and the second interlayer dielectric layer 213, wherein the third opening (not shown in the figure) exposes the surface of the first interlayer dielectric layer 204; forming a plurality of overlapping second interconnection layers 210 and a plurality of second conductive plugs 211 located between adjacent second interconnection layers 210 in the third opening (not shown in the figure), and forming a second conductive layer 212 in the fourth opening (not shown in the figure).

[0061] In this embodiment, the first interconnection member 205 is bonded to the second interconnection member 209 , and the first conductive layer 208 is bonded to the second conductive layer 212 , to form a first electrical interconnection structure.

[0062] In this embodiment, the number of the second conductive plugs 211 ranges from 1 to 5, and specifically, there is one second conductive plug 211 ; the material of the second interconnect layer 210 and the second conductive layer 212 is a conductive metal material, specifically aluminum.

[0063] In this embodiment, the first interlayer dielectric layer 204 and the second interlayer dielectric layer 213 are bonded to form an interlayer dielectric layer.

[0064] In this embodiment, the material of the interlayer dielectric layer includes silicon dioxide.

[0065] Please refer to Figure 8 , Figure 8 and Figure 7 The viewing direction is consistent. After forming the first electrical interconnection structure and the interlayer dielectric layer, a second substrate 214 is formed by bonding on the surface of the second interlayer dielectric layer 213 . The second substrate 214 includes a logic circuit.

[0066] In this embodiment, the material of the second substrate 214 includes silicon, germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium.

[0067] The following takes the example of the charge collection structure and the isolation structure being interconnected, and combines Figures 9 to 13 The formation process of the photoelectric sensor structure is described in detail.

[0068] Please refer to Fig. 9 , Fig. 9 and Figure 8 In line with the viewing direction, a first mask layer (not shown in the figure) is formed on the surface of the second surface b, and the first mask (not shown in the figure) exposes part of the surface of the second surface b; using the first mask layer (not shown in the figure) as a mask, the second surface b is etched to form a first groove 215 in the first substrate 200.

[0069] Please refer to Fig.10 , Fig.10 and Fig. 9 In the same viewing direction, an isolation structure is formed in the first trench 215 .

[0070] In this embodiment, the isolation structure includes: a first trench 215 located in the first substrate 100 ; a dielectric layer 218 located on the inner wall surface of the first trench 215 , an insulating layer 219 located on the surface of the dielectric layer 218 , and a second shielding layer 220 located on the surface of the insulating layer 219 .

[0071] Please refer to Fig.11 , Fig.11 and Fig.10In the same viewing direction, a second mask layer (not shown in the figure) is formed on the surface of the second surface b, and the second mask (not shown in the figure) exposes part of the surface of the second surface b; using the second mask layer (not shown in the figure) as a mask, the second surface b is etched to form a second groove 216 in the first substrate 200.

[0072] In this embodiment, the first groove 215 and the second groove 216 are interconnected and communicated.

[0073] In this embodiment, the process of etching the groove includes wet etching or dry etching. Wet etching is a technique of etching by immersing the etching material in an etching solution. It is a pure chemical etching with excellent selectivity. Wet etching is isotropic. Dry etching includes isotropic radial etching, reactive ion etching, sputtering etching, ion milling, ion beam assisted etching, reactive ion beam etching, etc. Dry etching is anisotropic.

[0074] Please refer to Fig.12 and Fig.13 , Fig.13 This is a top view of the structure. Fig.12 yes Fig.13 In the cross-sectional view along line AA1 , a charge collection structure is formed in the second trench 216 .

[0075] In this embodiment, the charge collection structure includes: a second trench 216 located in the first substrate 100 ; and a first shielding layer 217 located in the second trench 216 .

[0076] In this embodiment, the method for forming the isolation structure and the charge collection structure includes: forming a dielectric layer 218 on the inner wall surface of the first groove 215; forming an insulating layer 219 on the surface of the dielectric layer 218; and forming a second shielding layer 220 on the inner wall surface of the second groove 216.

[0077] In this embodiment, the method for forming the isolation structure and the charge collection structure also includes: one or more of chemical vapor deposition, physical deposition, atomic layer deposition, and jet vapor deposition, the deposition gas includes: hydrogen and monosilane, and the reaction temperature ranges from 400 degrees Celsius to 800 degrees Celsius.

[0078] In this embodiment, the charge collection structure is used to transfer the charges generated by the isolation structure to prevent charge accumulation in the isolation structure and prevent discharge.

[0079] In this embodiment, the isolation structure isolates the photosensitive doped region 203 from other regions of the first substrate 200 by connecting a reverse bias voltage, so as to form electrical isolation to prevent photoelectric crosstalk between adjacent pixel regions.

[0080] In this embodiment, the photoelectric sensor is electrically connected in the following manner: an electric field is applied to the first conductive layer 208 and the second conductive layer 212 in the device layer through a PAD structure (not shown in the figure), and the first conductive layer 208 and the second conductive layer 212 transfer the charge to the first substrate. Since there is no isolation structure in the charge collection structure, the charge in the first substrate 100 can be transferred to the charge collection structure, and the charge collection structure and the deep trench isolation structure are interconnected, and the metal material in the charge collection structure and the deep trench isolation structure is the same, thereby realizing the charge transfer.

[0081] In this embodiment, the thickness of the isolation structure ranges from 2 μm to 10 μm, and the thickness of the charge collection structure ranges from 0 μm to 4 μm.

[0082] In this embodiment, the material of the first shielding layer 217 includes aluminum and tungsten.

[0083] In this embodiment, the material of the second shielding layer 220 includes aluminum and tungsten; the material of the insulating layer 219 includes silicon oxide; and the material of the dielectric layer 218 includes a high-K dielectric.

[0084] In this embodiment, the photoelectric sensor further includes: a first dielectric layer 221 located on the surface of the second surface a and a first insulating layer 222 located on the surface of the first dielectric layer 221 .

[0085] Figures 14 to 16 It is a structural schematic diagram of the formation process of a photoelectric sensor in another embodiment of the present invention.

[0086] exist Figures 2 to 8 Based on Fig.14 , Fig.14 and Figure 8 In the same viewing direction, a third mask layer (not shown in the figure) is formed on the surface of the second surface b, and the third mask (not shown in the figure) exposes a portion of the surface of the second surface b; using the third mask layer (not shown in the figure) as a mask, the second surface b is etched to form a third trench 300 in the first substrate 200; an isolation structure is formed in the third trench 300; a fourth mask layer (not shown in the figure) is formed on the surface of the second surface b, and the fourth mask (not shown in the figure) exposes a portion of the surface of the second surface b; using the fourth mask layer (not shown in the figure) as a mask, the second surface b is etched to form a fourth trench 301 in the first substrate 200.

[0087] In this embodiment, the thickness of the third groove 300 is smaller than the thickness of the fourth groove 301 .

[0088] In this embodiment, the process of etching the groove includes wet etching or dry etching. Wet etching is a technique of etching by immersing the etching material in an etching solution. It is a pure chemical etching with excellent selectivity. Wet etching is isotropic. Dry etching includes isotropic radial etching, reactive ion etching, sputtering etching, ion milling, ion beam assisted etching, reactive ion beam etching, etc. Dry etching is anisotropic.

[0089] Please refer to Fig.15 and Fig.16 , Fig.16 This is a top view of the structure. Fig.15 yes Fig.16 In the cross-sectional schematic diagram along line BB1, an isolation structure is formed in the third trench 300; and a charge collection structure is formed in the fourth trench 301.

[0090] In this embodiment, the charge collection structure includes: a first shielding layer 302 located on the inner wall surface of the fourth groove 301 .

[0091] In this embodiment, the isolation structure includes: a dielectric layer 303 located on the inner wall surface of the third trench 300 , an insulating layer 304 located on the surface of the dielectric layer 303 , and a second shielding layer 305 located on the surface of the insulating layer 304 .

[0092] In this embodiment, the method for forming the isolation structure and the charge collection structure includes: forming a dielectric layer 303 on the inner wall surface of the third groove 300; forming an insulating layer 304 on the surface of the dielectric layer 303; forming a second shielding layer 305 on the surface of the insulating layer 304; and forming a first shielding layer 302 in the fourth groove 301.

[0093] In this embodiment, the method for forming the isolation structure and the charge collection structure also includes: one or more of chemical vapor deposition, physical deposition, atomic layer deposition, and jet vapor deposition, the deposition gas includes: hydrogen and monosilane, and the reaction temperature ranges from 400 degrees Celsius to 800 degrees Celsius.

[0094] In this embodiment, the charge collection structure is used to collect the charges generated by the isolation structure to prevent charge accumulation in the isolation structure.

[0095] In this embodiment, the isolation structure is used to isolate the photosensitive doping region 203 from other regions of the first substrate 200 to form electrical isolation and reduce optical crosstalk.

[0096] In this embodiment, the thickness of the isolation structure ranges from 2 μm to 10 μm, and the thickness of the charge collection structure ranges from 0 μm to 4 μm.

[0097] In this embodiment, the material of the first shielding layer 302 includes aluminum and tungsten.

[0098] In this embodiment, the material of the second shielding layer 305 includes aluminum and tungsten; the material of the insulating layer 304 includes silicon oxide; and the material of the dielectric layer 303 includes a high-K dielectric.

[0099] In this embodiment, the photoelectric sensor further includes: a first dielectric layer 306 located on the surface of the second surface a and a first insulating layer 307 located on the surface of the first dielectric layer 306 .

[0100] Please continue to refer to Fig.15 The technical solution of the present invention also provides a photoelectric sensor structure, including: a first substrate 200, the first substrate 200 includes a plurality of adjacent photosensitive areas I, and an isolation area II surrounding each photosensitive area I, the plurality of photosensitive areas I projected onto the surface of the first substrate 200 have the same pattern, each of the photosensitive areas I is adjacent to at least two photosensitive areas I, and each photosensitive area I includes at least two contour lines 201 parallel to the contours of the adjacent photosensitive areas I, and the two contour lines 201 intersect, and the angle 202 of the two intersecting contour lines 201 is an obtuse angle; a photosensitive doping area 203 located in the photosensitive area I; and an isolation structure located in the isolation area II.

[0101] In this embodiment, the contour line 201 is a straight line and a curve.

[0102] In this embodiment, when the contour line 201 is a curve, the angle 202 is the tangent angle 202 of the two contour lines 201 at the intersection point.

[0103] In this embodiment, the shape of the photosensitive area I includes an axisymmetric figure.

[0104] In this embodiment, the shape of the photosensitive area I includes a hexagon and a quadrilateral.

[0105] In this embodiment, the curve is "S" shaped.

[0106] In this embodiment, the photosensitive region I has a photosensitive doping region 203, and the first surface a exposes the photosensitive doping region 203. The doping type of the photosensitive doping region 203 is N-type doping, and the doping ions in the photosensitive doping region 203 include: arsenic, boron, carbon, boron fluoride, fluorine, phosphorus, nitrogen, aluminum, germanium or antimony.

[0107] In this embodiment, the photoelectric sensor structure further includes: a second groove 216 or a fourth groove 301 located in the first substrate 200; a charge collection structure located in the second groove 216 or the fourth groove 301, and the charge collection structure is adjacent to the plurality of photosensitive areas I.

[0108] In this embodiment, the charge collection structure includes: a first shielding layer 217 located in the second trench 216 and a first shielding layer 302 located in the fourth trench 301 .

[0109] In this embodiment, the material of the first shielding layer includes aluminum and tungsten; the thickness of the charge collection structure ranges from 0 μm to 4 μm.

[0110] In this embodiment, the isolation structure includes: a first trench 215 located in the first substrate 200; a dielectric layer 218 located on the inner wall surface of the first trench 215, an insulating layer 219 located on the surface of the dielectric layer 218, and a second shielding layer 220 located on the surface of the insulating layer 219.

[0111] In this embodiment, the isolation structure includes: a third trench 300 located in the first substrate 200 ; a dielectric layer 303 located on the inner wall surface of the third trench 300 , an insulating layer 304 located on the surface of the dielectric layer 303 , and a second shielding layer 305 located on the surface of the insulating layer 304 .

[0112] In this embodiment, the material of the second shielding layer 305 includes aluminum and tungsten; the material of the insulating layer 304 includes silicon oxide; the material of the dielectric layer 303 includes a high-K dielectric; and the thickness of the isolation structure ranges from 2 μm to 10 μm.

[0113] In this embodiment, the photoelectric sensor structure further includes: a second substrate 214 bonded to the first substrate 200 , the second substrate 214 having a logic circuit therein; the first substrate 200 includes a first surface a and a second surface b opposite to each other, the first surface a being the surface bonded toward the second substrate 214 .

[0114] In this embodiment, the material of the second substrate 214 includes silicon, germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium.

[0115] In this embodiment, the photoelectric sensor structure also includes: a device layer located on the surface of the first surface a, and the device layer includes: a first electrical interconnection structure, and the first electrical interconnection structure is electrically connected to one or more of the photosensitive doped region 203, the isolation structure, the charge collection structure and the logic circuit.

[0116] In this embodiment, the device layer further includes: an interlayer dielectric layer located on the surface of the first surface a, and the interlayer dielectric layer surrounds the first electrical interconnection structure.

[0117] In this embodiment, the material of the interlayer dielectric layer includes silicon dioxide.

[0118] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A photoelectric sensor structure, characterized in that: include: A first substrate, the first substrate comprising a plurality of adjacent photosensitive areas and an isolation area surrounding each photosensitive area, wherein the plurality of photosensitive areas are projected onto a surface of the first substrate in the same pattern, each of the photosensitive areas is adjacent to at least two photosensitive areas, and each of the photosensitive areas comprises at least two contour lines parallel to the contours of the adjacent photosensitive areas, and the two contour lines intersect, and the angle between the two intersecting contour lines is an obtuse angle; a photosensitive doped region located within the photosensitive region; An isolation structure is located within the isolation region.

2. The photoelectric sensor structure according to claim 1, characterized in that: The contour lines are straight lines and curved lines.

3. The photoelectric sensor structure according to claim 1, characterized in that: When the contour line is a curve, the angle is the angle between the tangents of the two contour lines at the intersection point.

4. The photoelectric sensor structure according to claim 1, characterized in that: The shape of the photosensitive area includes an axisymmetric figure.

5. The photoelectric sensor structure according to claim 2, characterized in that: The shapes of the photosensitive area include quadrilateral and hexagon.

6. The photoelectric sensor structure according to claim 3, characterized in that: The curve is "S" shaped.

7. The photoelectric sensor structure according to claim 1, characterized in that: Also includes: a second trench or a fourth trench located in the first substrate; A charge collection structure is located in the second trench or the fourth trench, and the charge collection structure is adjacent to the plurality of photosensitive regions.

8. The photoelectric sensor structure according to claim 7, characterized in that: The charge collection structure includes: a first shielding layer located in the second trench and the fourth trench.

9. The photoelectric sensor structure according to claim 8, characterized in that: The material of the first shielding layer includes aluminum and tungsten; the thickness of the charge collection structure ranges from 0 μm to 4 μm.

10. The photoelectric sensor structure according to claim 1, characterized in that: The isolation structure comprises: a first trench in a first substrate; a dielectric layer on an inner wall surface of the first trench, an insulating layer on a surface of the dielectric layer, and a second shielding layer on a surface of the insulating layer.

11. The photoelectric sensor structure according to claim 1, characterized in that: The isolation structure comprises: a third trench located in the first substrate; a dielectric layer located on the inner wall surface of the third trench, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

12. The photoelectric sensor structure according to claim 10 or 11, characterized in that: The material of the second shielding layer includes aluminum and tungsten; the material of the insulating layer includes silicon oxide; the material of the dielectric layer includes high-K dielectric; and the thickness of the isolation structure ranges from 2 μm to 10 μm.

13. The photoelectric sensor structure according to claim 1, characterized in that: Also includes: A second substrate bonded to the first substrate, wherein the second substrate has a logic circuit therein; the first substrate comprises a first surface and a second surface opposite to each other, wherein the first surface is a surface bonded toward the second substrate.

14. The photoelectric sensor structure according to claim 13, characterized in that: Also includes: A device layer is located on the surface of the first side, and the device layer includes: a first electrical interconnection structure, and the first electrical interconnection structure is electrically connected to one or more of the photosensitive doped region, the isolation structure, the charge collection structure and the logic circuit.

15. The photoelectric sensor structure according to claim 14, characterized in that: The device layer further includes: an interlayer dielectric layer located on the surface of the first side, and the interlayer dielectric layer surrounds the first electrical interconnection structure.

16. A method for forming a photoelectric sensor structure, characterized in that: include: A first substrate is provided, wherein the first substrate comprises a plurality of adjacent photosensitive regions and an isolation region surrounding each photosensitive region, wherein the plurality of photosensitive regions are projected onto a surface of the first substrate in the same pattern, each of the photosensitive regions is adjacent to at least two photosensitive regions, and each of the photosensitive regions comprises at least two contour lines parallel to the contours of the adjacent photosensitive regions, and the two contour lines intersect, and the angle between the two intersecting contour lines is an obtuse angle; forming a photosensitive doped region in the photosensitive region; An isolation structure is formed in the isolation region.

17. The method for forming a photoelectric sensor structure according to claim 16, wherein: Also includes: A charge collection structure is formed in the first substrate, and the charge collection structure is adjacent to the plurality of photosensitive regions.

18. The method for forming a photoelectric sensor structure according to claim 17, wherein: The charge collection structure and the isolation structure are interconnected, and the method for forming the charge collection structure and the isolation structure includes: forming a first mask layer on the surface of the second surface, the first mask exposing a portion of the surface of the second surface; using the first mask layer as a mask, etching the second surface to form a first groove in the first substrate; forming an isolation structure in the first groove; forming a second mask layer on the surface of the second surface, the second mask exposing a portion of the surface of the second surface; using the second mask layer as a mask, etching the second surface to form a second groove in the first substrate; forming a charge collection structure in the second groove; the charge collection structure includes: a first shielding layer located on the inner wall surface of the second groove; the isolation structure includes: a first groove located in the first substrate; a dielectric layer located on the inner wall surface of the first groove, an insulating layer located on the surface of the dielectric layer, and a second shielding layer located on the surface of the insulating layer.

19. The method for forming a photoelectric sensor structure according to claim 17, wherein: The charge collection structure and the isolation structure are formed in different grooves, and the method for forming the isolation structure and the charge collection structure includes: forming a third mask layer on the surface of the second surface, the third mask exposing a portion of the surface of the second surface; using the third mask layer as a mask, etching the second surface to form a third groove in the first substrate; forming an isolation structure in the third groove; forming a fourth mask layer on the surface of the second surface, the fourth mask exposing a portion of the surface of the second surface; using the fourth mask layer as a mask, etching the second surface to form a fourth groove in the first substrate; forming a charge collection structure in the fourth groove; the charge collection structure includes: a first shielding layer located on the inner wall surface of the fourth groove; the isolation structure includes: a second dielectric layer located on the inner wall surface of the third groove, a second insulating layer located on the surface of the second dielectric layer, and a second shielding layer located on the surface of the second insulating layer.

20. The method for forming a photoelectric sensor structure according to claim 19, wherein: Also includes: Before forming the isolation structure and the charge collection structure, a second substrate is formed by bonding on the first surface, wherein the second substrate includes a logic circuit, the first surface is the surface facing the second substrate for bonding, and the first substrate includes a first surface and a second surface opposite to each other.

21. The method for forming a photoelectric sensor structure according to claim 20, wherein: Also includes: Before bonding the second substrate, a device layer is formed on the surface of the first surface, wherein the device layer includes a first electrical interconnection structure and an interlayer dielectric layer located on the surface of the first surface, and the interlayer dielectric layer surrounds the first electrical interconnection structure.

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