Photoelectric sensor structure and forming method thereof

Abstract

The invention discloses a photoelectric sensor structure and a forming method thereof, and the structure comprises a first substrate which comprises a plurality of photosensitive regions which are separated from each other, and isolation regions which are located between the adjacent photosensitive regions and surround the photosensitive regions, and the first substrate comprises a first surface and a second surface which are opposite to each other; the first connecting structure is located in the isolation region and extends from the surface of the first surface to the second surface, and the size of the first connecting structure in the direction perpendicular to the first surface is smaller than the thickness of the first substrate; a device layer located on the surface of the first surface; the deep trench isolation structure is located in the isolation region, the deep trench isolation structure extends from the surface of the second surface to the first surface, and the deep trench isolation structure is in contact with the first connection structure; and a light-sensitive doped region located in the light-sensitive region. The bottom surface of the deep trench isolation structure is raised, the etching time is reduced, and the performance of the photoelectric sensor structure and the uniformity and stability of the manufacturing process are 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] As the pixel array expands, the problems of optical / electrical crosstalk and low photon detection efficiency become increasingly prominent. It is usually chosen to increase the DTI depth and reduce the DTI width to improve the photon detection efficiency. However, as the DTI depth increases and the width decreases, the DTI aspect ratio increases, the thickness of the epitaxial layer and the depth of the test structure also increase, resulting in an increase in etching time, and over-etching is prone to occur at the bottom of the DTI, resulting in the high-voltage isolation requirement between the DTI and the gate material layer not being met, affecting the performance of the photoelectric sensor. 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 reduce etching time and improve the performance of the photoelectric sensor.

[0005] To solve the above technical problems, an embodiment of the present invention provides a photoelectric sensor structure, including: a first substrate, the first substrate including a plurality of discrete photosensitive areas, and an isolation area located between adjacent photosensitive areas and surrounding the photosensitive areas, the first substrate including a first surface and a second surface relative to each other; a first connection structure located in the isolation area, the first connection structure extending from the surface of the first surface to the second surface, and a size of the first connection structure in a direction perpendicular to the first surface is smaller than a thickness of the first substrate; a device layer located on the surface of the first surface; a deep trench isolation structure located in the isolation area, the deep trench isolation structure extending from the surface of the second surface to the first surface, and the deep trench isolation structure is in contact with the first connection structure; and a photosensitive doping region located in the photosensitive area.

[0006] Optionally, the material of the first connection structure is aluminum, a size of the first connection structure in a direction perpendicular to the first surface ranges from 0 μm to 8 μm, and a size of the first connection structure in a direction parallel to the first surface ranges from 0 μm to 8 μm.

[0007] Optionally, the first substrate further includes a lead-out region.

[0008] Optionally, the photoelectric sensor structure also includes: a contact opening located in the lead-out area, the contact opening being recessed relative to the second surface, and the size of the contact opening in a direction perpendicular to the first surface being smaller than the thickness of the first substrate; a contact conductive layer located on the bottom surface of the contact opening, and a portion of the contact conductive layer passing through the bottom of the contact opening; a second connection structure located in the lead-out area, the second connection structure being in contact with the contact conductive layer, the second connection structure extending from the surface of the first surface to the second surface, and the size of the second connection structure in a direction perpendicular to the first surface being smaller than the thickness of the first substrate.

[0009] Optionally, the material of the second connection structure is aluminum, the size of the second connection structure in a direction perpendicular to the first surface ranges from 0 μm to 8 μm, and the size of the second connection structure in a direction parallel to the first surface ranges from 0 μm to 8 μm.

[0010] Optionally, the first substrate includes: a plurality of chip areas and a cutting road area surrounding the chip areas; the photosensitive area and the isolation area are located in the chip area.

[0011] Optionally, the photoelectric sensor structure further includes: a plurality of marking structures located in the cutting path area.

[0012] Optionally, the device layer includes: a high-voltage isolation structure located on the surface of the first surface, and at least one of the first connection structures is connected to the high-voltage isolation structure.

[0013] Optionally, the high-voltage isolation structure includes: an isolation layer located on a surface of the first connection structure and a floating gate located on a surface of the isolation layer.

[0014] Optionally, the device layer further includes: a third connection structure located on the surface of the first surface and the surface of the high-voltage isolation structure, wherein the third connection structure is electrically connected to one or more of the photosensitive doping region, the contact opening and the high-voltage isolation structure.

[0015] Optionally, the photosensor structure further includes: a charge collection structure located in the photosensitive area of ​​the second surface, wherein a size of the charge collection structure in a direction perpendicular to the first surface is smaller than a size of the deep trench isolation structure in a direction perpendicular to the first surface.

[0016] Optionally, the photoelectric sensor structure further includes: a fourth connection structure located between the deep trench isolation structure and the surface of the charge collection structure.

[0017] Optionally, the photoelectric sensor structure further includes: a passivation structure located on the second surface and the fourth connection structure surface, the passivation structure including a first passivation layer located on the second surface and a second passivation layer located on the first passivation layer and the fourth connection structure surface.

[0018] Optionally, the photoelectric sensor structure further includes: a second substrate bonded to the first substrate, wherein the second substrate has a logic circuit therein.

[0019] 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 discrete photosensitive areas, and an isolation area located between adjacent photosensitive areas and surrounding the photosensitive areas, the first substrate including a first surface and a second surface relative to each other; forming a first connection structure in the isolation area, the first connection structure extending from the surface of the first surface to the second surface, and the size of the first connection structure in a direction perpendicular to the first surface is smaller than the thickness of the first substrate; forming a deep trench isolation structure in the isolation area, the deep trench isolation structure extending from the surface of the second surface to the first surface, and the deep trench isolation structure is in contact with the first connection structure; forming a device layer on the surface of the first surface; forming a photosensitive doping area in the photosensitive area.

[0020] Optionally, the method for forming the first connection structure includes: etching a first surface of the isolation region to form a first opening, wherein a top width of the first opening is greater than a bottom width; and forming the first connection structure in the first opening.

[0021] Optionally, the first substrate also includes: a lead-out area; the lead-out area includes: a contact opening located in the lead-out area, the contact opening being recessed relative to the second surface, and the size of the contact opening in a direction perpendicular to the first surface being smaller than the thickness of the first substrate; a contact conductive layer located on the bottom surface of the contact opening, a portion of the contact conductive layer passing through the bottom of the contact opening; a second connection structure located in the lead-out area, the second connection structure being in contact with the contact conductive layer, the second connection structure extending from the surface of the first surface to the second surface, and the size of the second connection structure in a direction perpendicular to the first surface being smaller than the thickness of the first substrate.

[0022] Optionally, the method for forming the contact opening and the contact conductive layer includes: etching the second surface of the lead-out area to form an initial contact opening; etching the bottom of the initial contact opening to form a second opening and a contact opening; and forming a contact conductive layer in the second opening and on the bottom surface of the contact opening.

[0023] Optionally, the second connection structure is formed simultaneously with the first connection structure; the method for forming the second connection structure comprises: before forming the contact opening, etching the first surface of the lead-out region to form a third opening; and forming the second connection structure in the third opening.

[0024] Optionally, the first substrate further includes: a plurality of chip areas and a cutting path area surrounding the chip areas; the photosensitive area and the isolation area are located in the chip area; and the cutting path area includes a plurality of marking structures.

[0025] Optionally, the marking structure and the first connecting structure are formed simultaneously.

[0026] Optionally, the device layer includes a high-voltage isolation structure located on the surface of the first surface, at least one of the first connection structures being connected to the high-voltage isolation structure; and a third connection structure located on the surface of the first surface and the surface of the high-voltage isolation structure, the third connection structure being electrically connected to one or more of the photosensitive doped region, the contact opening and the high-voltage isolation structure.

[0027] Optionally, the method for forming the high-voltage isolation structure includes: forming an isolation layer on the surface of the first connection structure; forming a floating gate on the surface of the isolation layer; and the method for forming the third connection structure includes: forming a plurality of third connection structures on the surface of the floating gate and the surface of the first surface.

[0028] Optionally, the method for forming the photoelectric sensor structure also includes: after forming the deep trench isolation structure, etching the second surface of the photosensitive area to form a fourth opening; forming a charge collection structure in the fourth opening, the size of the charge collection structure in a direction perpendicular to the first surface is smaller than the size of the deep trench isolation structure in a direction perpendicular to the first surface, and the charge collection structure is an inverted trapezoid.

[0029] Optionally, the method for forming the photoelectric sensor structure further includes: after forming the charge collection structure, forming a fourth connection structure on the surface of the deep trench isolation structure and the charge collection structure, wherein the fourth connection structure is electrically connected to the deep trench isolation structure and the charge collection structure.

[0030] Optionally, the method for forming the photoelectric sensor structure also includes: after forming the fourth connecting structure, forming a passivation structure on the surface of the second surface and the surface of the fourth connecting structure, the passivation structure including a first passivation layer located on the surface of the second surface and a second passivation layer located on the surface of the first passivation layer and the surface of the fourth connecting structure.

[0031] Optionally, the method of passivation to form the passivation structure includes: before forming the fourth connecting structure, forming an initial first passivation layer on the second surface, the deep trench isolation structure surface and the charge collection structure surface; etching the initial first passivation layer to form a fifth opening, a sixth opening and a first passivation layer, the fifth opening exposing the deep trench isolation structure surface, the sixth opening exposing the charge collection structure surface, and part of the fourth connecting structure is located in the fifth opening and the sixth opening; after forming the fourth connecting structure, forming a second passivation layer on the first passivation layer surface and the fourth connecting structure surface.

[0032] Optionally, before forming the deep trench isolation structure, the charge collection structure and the fourth connection structure, a second substrate is formed by surface bonding on the first surface, wherein the second substrate includes a logic circuit.

[0033] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0034] In the photoelectric sensor structure provided in the technical solution of the present invention, the first connecting structure is located on the surface of the first surface, and the deep trench isolation structure is located on the surface of the first connecting structure, so that the bottom surface of the deep trench isolation structure is raised, thereby reducing the etching time, reducing the aspect ratio of the deep trench isolation structure, and thus reducing the resistance in the photoelectric sensor structure, thereby improving the performance of the photoelectric sensor structure and the uniformity and stability of the manufacturing process; and optical isolation between the bottom surface of the deep trench isolation structure and the photosensitive doping area is achieved through the first connecting structure, thereby avoiding the occurrence of optical crosstalk, thereby improving the performance of the photoelectric sensor structure.

[0035] Furthermore, in the technical solution of the present invention, the connection between the deep trench isolation structure and the high-voltage isolation structure is achieved through the first connecting structure, so that the deep trench isolation structure does not need to be in direct contact with the high-voltage isolation structure, thereby avoiding damage to the high-voltage isolation structure when the deep trench isolation structure is formed. Since there is no need to consider the damage to the high-voltage isolation structure, the optical isolation at the bottom of the isolation structure and the electrical isolation of the floating gate can be met. At the same time, the thickness of the high-voltage isolation structure is also reduced, thereby improving the performance of the photoelectric sensor and the uniformity and stability of the manufacturing process, thereby reducing the longitudinal size of the photoelectric sensor structure.

[0036] Furthermore, in the technical solution of the present invention, the second connecting structure is located on the surface of the first surface, and the contact opening and the contact conductive layer are located on the surface of the second connecting structure, so that the bottom surface of the contact opening is raised, thereby reducing the etching time, reducing the aspect ratio of the contact opening, and improving the performance of the photoelectric sensor structure as well as the uniformity and stability of the manufacturing process.

[0037] In the method for forming a photoelectric sensor structure provided in the technical solution of the present invention, a first connecting structure is formed on the surface of a first surface, and a deep trench isolation structure is formed on the surface of the first connecting structure, so that the bottom surface of the deep trench isolation structure is raised, thereby reducing the etching time, reducing the aspect ratio of the deep trench isolation structure, and thereby reducing the resistance within the photoelectric sensor structure, thereby improving the performance of the photoelectric sensor structure and the uniformity and stability of the manufacturing process; and optical isolation between the bottom surface of the deep trench isolation structure and the photosensitive doping region is achieved through the first connecting structure, thereby avoiding the occurrence of optical crosstalk, and thereby improving the performance of the photoelectric sensor structure.

[0038] Furthermore, in the technical solution of the present invention, a deep trench isolation structure and a high-voltage isolation structure are formed in the first connection structure to achieve connection between the deep trench isolation structure and the high-voltage isolation structure, so that the deep trench isolation structure does not need to be in direct contact with the high-voltage isolation structure, thereby avoiding damage to the high-voltage isolation structure when the deep trench isolation structure is formed. Since there is no need to consider the damage to the high-voltage isolation structure, when different high voltages are applied, the optical isolation at the bottom of the isolation structure and the electrical isolation of the floating gate can be met, and the thickness of the high-voltage isolation structure is also reduced, thereby improving the performance of the photoelectric sensor and the uniformity and stability of the manufacturing process, thereby reducing the longitudinal size of the photoelectric sensor structure.

[0039] Furthermore, in the technical solution of the present invention, a second connecting structure is formed on the surface of the first surface, and a contact opening and a contact conductive layer are formed on the surface of the second connecting structure, so that the bottom surface of the contact opening is raised, thereby reducing the etching time, reducing the aspect ratio of the contact opening, and improving the performance of the photoelectric sensor structure as well as the uniformity and stability of the manufacturing process; in addition, as the depth of the contact opening decreases, when the photoresist is formed on the first substrate, the photoresist flowing into the contact opening is reduced, thereby reducing the thickness of the photoresist in the contact opening, reducing the energy required for litho exposure, and not easily contaminating the machine, thereby reducing the difficulty of the manufacturing process and improving mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the structure of a photoelectric sensor;

[0041] Figures 2 to 13 It is a structural schematic diagram of the formation process of the photoelectric sensor in one embodiment of the present invention. DETAILED DESCRIPTION

[0042] 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.

[0043] As described in the background art, it is necessary to improve the performance of photoelectric sensors and reduce the process difficulty. Now, an analysis and description will be given in conjunction with specific embodiments.

[0044] Figure 1 It is a structural diagram of a photoelectric sensor.

[0045] Please refer to Figure 1 The photoelectric sensor structure includes: a first substrate 100, the first substrate 100 includes a plurality of mutually discrete photosensitive regions I, and an isolation region II located between adjacent photosensitive regions I and surrounding the photosensitive regions I, the first substrate 100 includes a first surface a and a second surface b opposite to each other; a device layer 106 located on the surface of the first surface a; a deep trench isolation structure 102 located in the isolation region II, the deep trench isolation structure 102 runs through the first substrate 100; and a photosensitive doping region 103 located in the photosensitive region I.

[0046] In this embodiment, the photoelectric sensor structure further includes: an isolation layer 104 located on the surface of the deep trench isolation structure 102 on the first surface a and a floating gate 105 located on the surface of the isolation layer 104 .

[0047] In this embodiment, the photoelectric sensor structure further includes: a lead-out region III and a contact opening 101 located in the lead-out region III.

[0048] In the above scheme, on the one hand, since the deep trench isolation structure 102 in this scheme passes through the first substrate 100, before forming the deep trench isolation structure 102, the bottom of the first substrate 100 needs to be completely etched to form a deep trench passing through the first substrate (not shown in the figure), which results in over-etching when etching the bottom of the first substrate 100, damaging the isolation layer 104, and then reducing the thickness of the isolation layer 104. Since high voltage will be applied between the floating gate and the deep trench isolation structure, the high-voltage isolation requirement between the deep trench isolation structure 102 and the floating gate 105 needs to be achieved through the isolation layer 104. The reduction in the thickness of the isolation layer 104 affects the high-voltage isolation requirement between the deep trench isolation structure 102 and the floating gate 105, thereby affecting the performance of the photoelectric sensor. On the other hand, since the contact opening 101 penetrates the first substrate 100 and part of the device layer 106, that is, the depth of the contact opening 101 increases, the etching time of the contact opening 101 increases, and the thickness of the photoresist (not shown in the figure) flowing into the contact opening 101 also increases accordingly. The energy required for subsequent litho exposure increases, which is easy to contaminate the machine and is not conducive to mass production.

[0049] 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 first connecting structure is located on the surface of the first surface, and the deep trench isolation structure is located on the surface of the first connecting structure, so that the bottom surface of the deep trench isolation structure is raised, thereby reducing the etching time, reducing the aspect ratio of the deep trench isolation structure, and thereby reducing the resistance in the photoelectric sensor structure, thereby improving the performance of the photoelectric sensor structure and the uniformity and stability of the manufacturing process; and optical isolation between the bottom surface of the deep trench isolation structure and the photosensitive doping region is achieved through the first connecting structure, thereby avoiding the occurrence of optical crosstalk, and thereby improving the performance of the photoelectric sensor structure.

[0050] 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.

[0051] Figures 2 to 13 It is a structural schematic diagram of the formation process of the photoelectric sensor in one embodiment of the present invention.

[0052] Please refer to Figure 2 A first substrate 200 is provided, the first substrate 200 comprising a plurality of mutually discrete photosensitive regions I, an isolation region II located between adjacent photosensitive regions I and surrounding the photosensitive regions I, and a lead-out region III, the first substrate 200 comprising a first surface a and a second surface b opposite to each other; the first surface a of the isolation region II is etched to form a first opening 202; the first surface a of the lead-out region III is etched to form a third opening 203.

[0053] 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.

[0054] 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.

[0055] In this embodiment, the method for forming the first opening 202 and the third opening 203 includes: forming a first mask layer (not shown in the figure) on the first surface a, wherein the first mask layer (not shown in the figure) exposes a portion of the surface of the first surface a; and etching the first surface a using the first mask layer (not shown in the figure) as a mask to form the first opening 202 and the third opening 203.

[0056] In this embodiment, the top widths of the first opening 202 and the third opening 203 are both greater than the bottom widths, and the dimension of the first opening 202 in a direction parallel to the first surface a is smaller than the dimension of the third opening 203 in a direction parallel to the first surface a.

[0057] 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.

[0058] In this embodiment, it also includes: forming a photosensitive doping region 201 in the photosensitive region I, the first surface a exposes the photosensitive doping region 201, the doping type of the photosensitive doping region 201 is N-type doping, and the doping ions in the photosensitive doping region 201 include: arsenic, boron, carbon, boron fluoride, fluorine, phosphorus, nitrogen, aluminum, germanium or antimony.

[0059] In this embodiment, the photosensitive doped region 201 is used to achieve photoelectric conversion. Specifically, light is incident on the photoelectric sensor from the second surface b.

[0060] In this embodiment, the first substrate 200 further includes: a plurality of chip regions and a scribe line region IV surrounding the chip regions; the photosensitive region I and the isolation region II are located in the chip regions.

[0061] In this embodiment, the chip area includes a photosensitive area I, an isolation area II and a lead-out area III.

[0062] Please refer to Figure 3 , a first connection structure 204 is formed in the isolation region II, and the first connection structure 204 extends from the surface of the first surface a to the second surface b; and a second connection structure 205 is formed in the third opening 203.

[0063] In this embodiment, the second connection structure 205 and the first connection structure 204 are formed simultaneously.

[0064] In this embodiment, the first connection structure 204 is used to raise the bottom surface of the subsequently formed deep trench isolation structure, reduce the etching time of the deep trench, reduce the aspect ratio of the deep trench isolation structure, and ensure high-voltage isolation between the deep trench isolation structure and the floating gate through the first connection structure.

[0065] In this embodiment, the second connection structure 205 is used to raise the bottom surface of the contact opening formed subsequently, thereby reducing the etching time of the contact opening and lowering the aspect ratio of the contact opening.

[0066] In this embodiment, the method for forming the first connection structure 204 and the second connection structure 205 includes: depositing an initial first connection structure (not shown in the figure) and an initial second connection structure (not shown in the figure) on the surface of the first surface a and in the first openings 202 and the third openings 203; and flattening the initial first connection structure (not shown in the figure) and the initial second connection structure (not shown in the figure) until the surface of the first surface a is exposed, thereby forming the first connection structure 204 and the second connection structure 205.

[0067] The deposition method includes: one or more of thermal oxidation, rapid thermal annealing, chemical vapor deposition, physical deposition, atomic layer deposition, and jet vapor deposition.

[0068] The planarization method includes: a chemical mechanical polishing process.

[0069] In this embodiment, the size of the first connection structure 204 in the direction perpendicular to the first surface a is smaller than the thickness of the first substrate 200 , and the thickness of the first connection structure 204 is the same as that of the second connection structure 205 .

[0070] In this embodiment, the second connection structure 205 extends from the first surface a to the second surface b, and a dimension of the second connection structure 205 in a direction perpendicular to the first surface a is smaller than a thickness of the first substrate 200 .

[0071] In this embodiment, the first connection structure 204 includes a plurality of first conductive plugs, the second connection structure 205 includes a second conductive plug, and the materials of the first connection structure 204 and the second connection structure 205 include metal conductive materials, specifically aluminum; the number of the first connection structures 204 and the second connection structures 205 is the same as the number of the isolation region II.

[0072] In this embodiment, the method further includes: forming a plurality of marking structures 227 in the scribe line region IV.

[0073] In this embodiment, the marking structure 227 is used to mark the position of the cutting lane region IV to achieve alignment of the subsequently formed structure.

[0074] In this embodiment, the method for forming the mark structure 227 includes: etching the second surface b of the cutting street area IV to form a cutting groove; and forming the mark structure 227 in the cutting groove.

[0075] In this embodiment, the marking structure 227 and the first connection structure 204 are formed simultaneously.

[0076] Please refer to Figure 4A device layer is formed on the surface of the first surface a, and a high-voltage isolation structure and a third connection structure are formed in the device layer. The high-voltage isolation structure is located on the surface of the first surface a. At least one of the first connection structures 204 is connected to the high-voltage isolation structure; the third connection structure is located on the surface of the first surface a and the surface of the high-voltage isolation structure, and the third connection structure is electrically connected to one or more of the photosensitive doped region 201, the contact opening 225 and the high-voltage isolation structure.

[0077] In this embodiment, the third connection structure includes a plurality of third conductive plugs 209 , and the material of the third connection structure includes a metal conductive material, specifically aluminum.

[0078] In this embodiment, the high-voltage isolation structure includes: an isolation layer 207 located on the surface of the first connection structure 204 and a floating gate 208 located on the surface of the isolation layer 207 .

[0079] In this embodiment, the high-voltage isolation structure is used to achieve optical isolation at the bottom of the deep trench isolation structure and high-voltage isolation between the floating gate 208 and the deep trench isolation structure.

[0080] In this embodiment, the process further includes: before forming the high-voltage isolation structure and the third connection structure, forming a first dielectric layer 206 and a second dielectric layer 229 on the surface of the first surface a.

[0081] In this embodiment, the method for forming the high-voltage isolation structure and the third connection structure includes: forming an initial first dielectric layer (not shown in the figure) on the surface of the first surface a, etching the initial first dielectric layer (not shown in the figure) to form a plurality of seventh openings and a first dielectric layer 206, wherein the seventh opening exposes the surface of the first connection structure 204; forming an isolation layer 207 and a floating gate 208 located on the surface of the isolation layer 207 in the seventh opening; forming an initial second dielectric layer (not shown in the figure) on the surface of the first surface a, etching the initial second dielectric layer (not shown in the figure) and the first dielectric layer 206 to form a plurality of eighth openings, a ninth opening and a second dielectric layer 229, wherein the eighth opening exposes the surface of the floating gate 208, and the ninth opening exposes the surface of the second connection structure 205; and forming a third conductive plug 209 in the eighth opening and the ninth opening.

[0082] In this embodiment, the material of the isolation layer 207 includes silicon oxide and silicon nitride.

[0083] In this embodiment, the third connection structure further includes a first conductive layer 211 , a second conductive layer 213 and a fourth conductive plug 212 .

[0084] Please refer to Figure 5 Before forming the third connection structure, a third dielectric layer 210 is formed on the surface of the first surface a.

[0085] In this embodiment, the method for forming the third connection structure further includes: forming an initial third dielectric layer (not shown in the figure) on the surface of the second dielectric layer 229, etching the initial third dielectric layer (not shown in the figure) to form a plurality of tenth openings and a third dielectric layer 210, wherein the tenth opening exposes the surface of the third conductive plug 209; forming a first conductive layer 211, a second conductive layer 213 and a fourth conductive plug 212 in the tenth opening, wherein the first conductive layer 211 and the second conductive layer 213 are electrically connected via the fourth conductive plug 212.

[0086] Please refer to Figure 6 , a second substrate 214 is bonded on the surface of the first surface a to form a second substrate 214, wherein the second substrate 214 includes a logic circuit.

[0087] In this embodiment, the material of the second substrate 214 includes silicon, germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium.

[0088] Please refer to Figure 7 , a second mask layer (not shown in the figure) is formed on the second surface b, and the second mask layer exposes a portion of the surface of the second surface b; using the second mask layer as a mask, the surface of the second surface b is etched to form a plurality of deep grooves 215, and the bottom of the deep grooves 215 exposes the surface of the first connection structure 204.

[0089] In this embodiment, the process further includes: etching the second surface b to form a plurality of eleventh openings 231 .

[0090] In this embodiment, the depth of the deep trench 215 ranges from 0 μm to 8 μm.

[0091] In this embodiment, the shape of the eleventh opening 231 includes an inverted pyramid.

[0092] Please refer to Figure 8 , the second surface b of the photosensitive area I is etched to form a fourth opening 216.

[0093] In this embodiment, the method for forming the fourth opening 216 includes: forming a third mask layer (not shown in the figure) on the second surface b, wherein the third mask layer exposes a portion of the surface of the second surface b; using the third mask layer as a mask, etching the surface of the second surface b to form the fourth opening 216.

[0094] Please refer to Fig. 9 , a deep trench isolation structure is formed in the isolation region II, the deep trench isolation structure extends from the surface of the second surface b to the first surface a, and the deep trench isolation structure is in contact with the first connection structure 204; a charge collection structure is formed in the fourth opening 216.

[0095] In this embodiment, the charge collection structure is used to collect the charges generated by the deep trench isolation structure to prevent charge accumulation in the deep trench isolation structure.

[0096] In this embodiment, the deep trench isolation structure includes an insulating layer 217 located on the surface of the deep trench 215 and a first shielding layer 218 located on the surface of the insulating layer 217 ; the charge collection structure includes a second shielding layer 219 .

[0097] In this embodiment, the method for forming a deep trench isolation structure and a charge collection structure includes: depositing an initial insulating layer (not shown in the figure) on the surface of the deep trench 215; depositing an initial first shielding layer (not shown in the figure) on the surface of the initial insulating layer (not shown in the figure), and depositing an initial second shielding layer (not shown in the figure) in the fourth opening 216; and flattening the initial insulating layer (not shown in the figure), the initial first shielding layer (not shown in the figure) and the initial second shielding layer (not shown in the figure) until the surface of the second surface b is exposed, thereby forming an insulating layer 217, a first shielding layer 218 and a second shielding layer 219.

[0098] In this embodiment, the size of the charge collection structure in a direction perpendicular to the first surface a is smaller than the size of the deep trench isolation structure in a direction perpendicular to the first surface a, and the charge collection structure is an inverted trapezoid.

[0099] In this embodiment, the materials of the first shielding layer 218 and the second shielding layer 219 include aluminum and tungsten; the material of the insulating layer 217 includes silicon oxide.

[0100] Please refer to Fig.10 After the charge collection structure is formed, a fourth connection structure is formed on the surface of the deep trench isolation structure and the charge collection structure, and the fourth connection structure is electrically connected to the deep trench isolation structure and the charge collection structure.

[0101] In this embodiment, it also includes forming an initial first passivation layer (not shown in the figure) on the surface of the second surface b, in the eleventh opening 231, on the surface of the deep trench isolation structure and on the surface of the charge collection structure before forming the fourth connecting structure; etching the initial first passivation layer (not shown in the figure) to form a fifth opening 221, a sixth opening 222 and a first passivation layer 220, wherein the fifth opening 221 exposes the surface of the first shielding layer 218, and the sixth opening 222 exposes the surface of the second shielding layer 219.

[0102] In this embodiment, the fourth connection structure includes a plurality of fifth conductive plugs 230 and a third conductive layer 224 .

[0103] In this embodiment, the material of the fourth connection structure includes a metal conductive material, specifically aluminum.

[0104] Please refer to Fig.11 , a plurality of fifth conductive plugs 230 are formed in the fifth opening 221 and the sixth opening 222 ; a third conductive layer 224 is formed on the surface of the plurality of fifth conductive plugs 230 and on the surface of part of the first passivation layer 220 ; and the second passivation layer 223 is formed on the surface of the third conductive layer 224 , and the second passivation layer 223 surrounds the third conductive layer 224 .

[0105] In this embodiment, the material of the first passivation layer 220 and the second passivation layer 223 includes silicon dioxide.

[0106] 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 schematic diagram along the AA1 line, a contact opening 225 is formed in the lead-out area III, and the contact opening 225 is recessed relative to the second surface b, and the size of the contact opening 225 in the direction perpendicular to the first surface a is smaller than the thickness of the first substrate 200; a contact conductive layer 228 is located on the bottom surface of the contact opening 225, and a portion of the contact conductive layer 228 passes through the bottom of the contact opening 225, and the second connection structure 205 is in contact with the contact conductive layer 228.

[0107] In this embodiment, the method for forming the contact opening 225 and the contact conductive layer 228 includes: etching the second surface b of the lead-out area III to form an initial contact opening (not shown in the figure); etching the bottom of the initial contact opening (not shown in the figure) to form a second opening and a contact opening 225; and forming a contact conductive layer 228 in the second opening and on the bottom surface of the contact opening 225.

[0108] In this embodiment, after the contact opening 225 is formed, a contact layer 226 is formed on the surface of the contact opening 225 .

[0109] In this embodiment, the depth of the contact opening 225 ranges from 0 μm to 10 μm.

[0110] Please continue to refer to Fig.12 and Fig.13The 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 mutually discrete photosensitive regions I, and an isolation region II located between adjacent photosensitive regions I and surrounding the photosensitive regions I, the first substrate 200 includes a first surface a and a second surface b relative to each other; a first connection structure 204 located in the isolation region II, the first connection structure 204 extends from the surface of the first surface a to the second surface b, and the size of the first connection structure 204 in a direction perpendicular to the first surface a is smaller than the thickness of the first substrate 200; a device layer located on the surface of the first surface a; a deep trench isolation structure located in the isolation region II, the deep trench isolation structure extends from the surface of the second surface b to the first surface a, and the deep trench isolation structure is in contact with the first connection structure 204; a photosensitive doping region 201 located in the photosensitive region I.

[0111] In this embodiment, the material of the first substrate 200 includes silicon carbide, silicon germanium, a multi-component semiconductor material composed of group III-V elements, silicon on insulator (SOI) or germanium on insulator (GOI). Among them, the multi-component semiconductor material composed of group III-V elements includes InP, GaAs, GaP, InAs, InSb, InGaAs or InGaAsP.

[0112] In this embodiment, the doping type of the photosensitive doping region 201 is N-type doping, and the doping ions in the photosensitive doping region 201 include: arsenic, boron, carbon, boron fluoride, fluorine, phosphorus, nitrogen, aluminum, germanium or antimony.

[0113] In this embodiment, the material of the first connection structure 204 is aluminum, the size of the first connection structure 204 in a direction perpendicular to the first surface a ranges from 0 μm to 10 μm, and the size of the first connection structure 204 in a direction parallel to the first surface a ranges from 0 μm to 10 μm.

[0114] In this embodiment, the first substrate 200 further includes a lead-out region III.

[0115] In this embodiment, the photoelectric sensor structure also includes: a contact opening 225 located in the lead-out area III, the contact opening 225 is recessed relative to the second surface b, and the size of the contact opening 225 in a direction perpendicular to the first surface a is smaller than the thickness of the first substrate 200; a contact conductive layer 228 located on the bottom surface of the contact opening 225, and a portion of the contact conductive layer 228 passes through the bottom of the contact opening 225; a second connection structure 205 located in the lead-out area III, the second connection structure 205 is in contact with the contact conductive layer 228, the second connection structure 205 extends from the surface of the first surface a to the second surface b, and the size of the second connection structure 205 in a direction perpendicular to the first surface a is smaller than the thickness of the first substrate 200.

[0116] In this embodiment, the material of the second connection structure 205 is aluminum, the size of the second connection structure 205 in a direction perpendicular to the first surface a ranges from 0 μm to 10 μm, and the size of the second connection structure 205 in a direction parallel to the first surface a ranges from 0 μm to 10 μm.

[0117] In this embodiment, the first substrate 200 includes: a plurality of chip areas and a scribe line area IV surrounding the chip areas; the photosensitive area I and the isolation area II are located in the chip areas.

[0118] In this embodiment, the photoelectric sensor structure further includes: a plurality of marking structures 227 located in the scribe line region IV.

[0119] In this embodiment, the device layer includes: a high-voltage isolation structure located on the surface of the first surface a, and at least one of the first connection structures 204 is connected to the high-voltage isolation structure.

[0120] In this embodiment, the high-voltage isolation structure includes: an isolation layer 207 located on the surface of the first connection structure 204 and a floating gate 208 located on the surface of the isolation layer 207 .

[0121] In this embodiment, the device layer also includes: a third connection structure located on the surface of the first surface a and the surface of the high-voltage isolation structure, and the third connection structure is electrically connected to one or more of the photosensitive doped region 201, the contact opening 225 and the high-voltage isolation structure.

[0122] In this embodiment, the photoelectric sensor structure also includes: a charge collection structure located in the photosensitive area I of the second surface b, and the size of the charge collection structure in the direction perpendicular to the first surface a is smaller than the size of the deep trench isolation structure in the direction perpendicular to the first surface a.

[0123] In this embodiment, the photoelectric sensor structure further includes: a fourth connection structure located on the surface of the deep trench isolation structure and the charge collection structure.

[0124] In this embodiment, the photoelectric sensor structure also includes: a passivation structure located on the surface of the second surface b and the surface of the fourth connection structure, the passivation structure includes a first passivation layer 220 located on the surface of the second surface b and a second passivation layer 223 located on the surface of the first passivation layer 220 and the surface of the fourth connection structure.

[0125] In this embodiment, the material of the first passivation layer 220 and the second passivation layer 223 includes silicon dioxide.

[0126] In this embodiment, the photoelectric sensor structure further includes: a second substrate 214 bonded to the first substrate 200 , and the second substrate 214 has a logic circuit therein.

[0127] In this embodiment, the material of the second substrate 214 includes silicon, germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium.

[0128] 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 mutually separated photosensitive regions and an isolation region located between adjacent photosensitive regions and surrounding the photosensitive regions, the first substrate comprising a first surface and a second surface opposite to each other; A first connection structure located in the isolation region, the first connection structure extending from the first surface to the second surface, and a dimension of the first connection structure in a direction perpendicular to the first surface is smaller than a thickness of the first substrate; A device layer located on the surface of the first side; A deep trench isolation structure located in the isolation region, the deep trench isolation structure extending from the second surface to the first surface, and the deep trench isolation structure is in contact with the first connection structure; A photosensitive doped region is located in the photosensitive region.

2. The photoelectric sensor structure according to claim 1, characterized in that: The material of the first connection structure is aluminum. The size of the first connection structure in a direction perpendicular to the first surface ranges from 0 μm to 8 μm. The size of the first connection structure in a direction parallel to the first surface ranges from 0 μm to 8 μm.

3. The photoelectric sensor structure according to claim 1, characterized in that: The first substrate further includes a lead-out region.

4. The photoelectric sensor structure according to claim 3, characterized in that: Also includes: A contact opening located in the lead-out region, wherein the contact opening is recessed relative to the second surface, and a dimension of the contact opening in a direction perpendicular to the first surface is smaller than a thickness of the first substrate; A contact conductive layer located on the bottom surface of the contact opening, wherein a portion of the contact conductive layer passes through the bottom of the contact opening; A second connection structure is located in the lead-out area, the second connection structure is in contact with the contact conductive layer, the second connection structure extends from the first surface to the second surface, and the size of the second connection structure in a direction perpendicular to the first surface is smaller than the thickness of the first substrate.

5. The photoelectric sensor structure according to claim 4, characterized in that: The material of the second connection structure is aluminum, the size of the second connection structure in a direction perpendicular to the first surface ranges from 0 μm to 8 μm, and the size of the second connection structure in a direction parallel to the first surface ranges from 0 μm to 8 μm.

6. The photoelectric sensor structure according to claim 1, characterized in that: The first substrate includes: a plurality of chip areas and a cutting road area surrounding the chip areas; the photosensitive area and the isolation area are located in the chip area.

7. The photoelectric sensor structure according to claim 6, characterized in that: Also includes: A number of marking structures are located within the scribe line area.

8. The photoelectric sensor structure according to claim 1, characterized in that: The device layer comprises: a high-voltage isolation structure located on the surface of the first surface, and at least one of the first connection structures is connected to the high-voltage isolation structure.

9. The photoelectric sensor structure according to claim 8, characterized in that: The high-voltage isolation structure includes: an isolation layer located on the surface of the first connection structure and a floating gate located on the surface of the isolation layer.

10. The photoelectric sensor structure according to claim 9, characterized in that: The device layer further includes: a third connection structure located on the surface of the first surface and the surface of the high-voltage isolation structure, wherein the third connection structure is electrically connected to one or more of the photosensitive doping region, the contact opening and the high-voltage isolation structure.

11. The photoelectric sensor structure according to claim 1, characterized in that: Also includes: A charge collection structure located in the photosensitive region of the second surface, wherein the size of the charge collection structure in a direction perpendicular to the first surface is smaller than the size of the deep trench isolation structure in a direction perpendicular to the first surface.

12. The photoelectric sensor structure according to claim 11, characterized in that: Also includes: A fourth connection structure is located between the deep trench isolation structure and the surface of the charge collection structure.

13. The photoelectric sensor structure according to claim 12, characterized in that: Also includes: A passivation structure is located on the surface of the second surface and the surface of the fourth connection structure, and the passivation structure includes a first passivation layer located on the surface of the second surface and a second passivation layer located on the surface of the first passivation layer and the surface of the fourth connection structure.

14. 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.

15. A method for forming a photoelectric sensor structure, characterized in that: include: Providing a first substrate, the first substrate comprising a plurality of mutually discrete photosensitive regions and an isolation region located between adjacent photosensitive regions and surrounding the photosensitive regions, the first substrate comprising a first surface and a second surface opposite to each other; forming a first connection structure in the isolation region, wherein the first connection structure extends from the first surface to the second surface, and a dimension of the first connection structure in a direction perpendicular to the first surface is smaller than a thickness of the first substrate; forming a deep trench isolation structure in the isolation region, wherein the deep trench isolation structure extends from the second surface to the first surface, and the deep trench isolation structure contacts the first connection structure; forming a device layer on the surface of the first surface; A photosensitive doped region is formed in the photosensitive region.

16. The method for forming a photoelectric sensor structure according to claim 15, wherein: The method for forming the first connection structure includes: etching the first surface of the isolation region to form a first opening, wherein the top width of the first opening is greater than the bottom width; and forming the first connection structure in the first opening.

17. The method for forming a photoelectric sensor structure according to claim 16, wherein: The first substrate also includes: a lead-out area; the lead-out area includes: a contact opening located in the lead-out area, the contact opening is recessed relative to the second surface, and the size of the contact opening in a direction perpendicular to the first surface is smaller than the thickness of the first substrate; a contact conductive layer located on the bottom surface of the contact opening, and part of the contact conductive layer passes through the bottom of the contact opening; a second connection structure located in the lead-out area, the second connection structure is in contact with the contact conductive layer, the second connection structure extends from the surface of the first surface to the second surface, and the size of the second connection structure in a direction perpendicular to the first surface is smaller than the thickness of the first substrate.

18. The method for forming a photoelectric sensor structure according to claim 17, wherein: The method for forming the contact opening and the contact conductive layer comprises: etching the second surface of the lead-out region to form an initial contact opening; etching the bottom of the initial contact opening to form a second opening and a contact opening; and forming a contact conductive layer in the second opening and on the bottom surface of the contact opening.

19. The method for forming a photoelectric sensor structure according to claim 18, wherein: The second connection structure is formed simultaneously with the first connection structure; The method for forming the second connection structure includes: before forming the contact opening, etching the first surface of the lead-out region to form a third opening; A second connection structure is formed in the third opening.

20. The method for forming a photoelectric sensor structure according to claim 15, wherein: The first substrate further includes: a plurality of chip regions and a cutting path region surrounding the chip regions; the photosensitive region and the isolation region are located in the chip regions; and the cutting path region includes a plurality of marking structures.

21. The method for forming a photoelectric sensor structure according to claim 20, wherein: The marking structure is formed simultaneously with the first connecting structure.

22. The method for forming a photoelectric sensor structure according to claim 15, wherein: The device layer includes a high-voltage isolation structure located on the surface of the first surface, at least one of the first connection structures is connected to the high-voltage isolation structure; and a third connection structure located on the surface of the first surface and the surface of the high-voltage isolation structure, the third connection structure is electrically connected to one or more of the photosensitive doped region, the contact opening and the high-voltage isolation structure.

23. The method for forming a photoelectric sensor structure according to claim 22, wherein: The method for forming the high voltage isolation structure includes: forming an isolation layer on the surface of the first connection structure; forming a floating gate on the surface of the isolation layer; the method for forming the third connection structure includes: forming a plurality of third connection structures on the surface of the floating gate and the surface of the first surface.

24. The method for forming a photoelectric sensor structure according to claim 15, wherein: Also includes: After forming the deep trench isolation structure, etching the second surface of the photosensitive region to form a fourth opening; A charge collection structure is formed in the fourth opening. The size of the charge collection structure in a direction perpendicular to the first surface is smaller than the size of the deep trench isolation structure in a direction perpendicular to the first surface. The charge collection structure is an inverted trapezoid.

25. The method for forming a photoelectric sensor structure according to claim 24, wherein: Also includes: After the charge collection structure is formed, a fourth connection structure is formed on the surface of the deep trench isolation structure and the charge collection structure, and the fourth connection structure is electrically connected to the deep trench isolation structure and the charge collection structure.

26. The method for forming a photoelectric sensor structure according to claim 25, wherein: Also includes: After forming the fourth connection structure, a passivation structure is formed on the second surface and the fourth connection structure surface, the passivation structure comprising a first passivation layer located on the second surface and a second passivation layer located on the first passivation layer surface and the fourth connection structure surface.

27. The method for forming a photoelectric sensor structure according to claim 26, wherein: The method for passivating to form the passivation structure includes: before forming the fourth connection structure, forming an initial first passivation layer on the second surface, the deep trench isolation structure surface and the charge collection structure surface; etching the initial first passivation layer to form a fifth opening, a sixth opening and a first passivation layer, the fifth opening exposing the deep trench isolation structure surface, the sixth opening exposing the charge collection structure surface, and part of the fourth connection structure is located in the fifth opening and the sixth opening; after forming the fourth connection structure, forming a second passivation layer on the first passivation layer surface and the fourth connection structure surface.

28. The method for forming a photoelectric sensor structure according to claim 27, wherein: Before forming the deep trench isolation structure, the charge collection structure and the fourth connection structure, a second substrate is formed by surface bonding on the first surface, wherein the second substrate includes a logic circuit.

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