Organic photodiode and method for manufacturing same

Abstract

The invention provides an organic photodiode and a manufacturing method thereof. The organic photodiode includes: an element formed in a substrate; the interconnection structure is formed above the element and is connected with the element; the bottom electrode is completely formed in the upper surface of the oblique angle plate, the contact area between the bottom electrode and the oblique angle plate and the pixel size are at the same order of magnitude, and the upper surface of the oblique angle plate exceeds the pixel size; and the organic layer is formed on the bottom electrode and is connected with the bottom electrode.

Description

Technical Field

[0001] This invention relates to organic photodiodes, and more specifically, to organic photodiodes having a bottom electrode formed entirely within the vertically projected area of ​​the upper surface of an inclined plate. The invention also relates to a method for manufacturing this organic photodiode. Background Technology

[0002] Figure 1A This diagram shows a cross-sectional view of a known organic photodiode. Organic photodiodes (OPDs) have demonstrated enormous application potential in fields such as optical imaging, sensing, and communication due to their wide range of photoelectric tunability, low-temperature and easily processed manufacturing processes, and superior mechanical flexibility. Figure 1A Two organic photodiodes 10 are shown. Each organic photodiode 10 includes an element 12, an interconnect structure 13, a bottom electrode 14, and an organic layer 15. The element 12 is formed in a substrate 11. The interconnect structure 13 is formed on the element 12. The bottom electrode 14 is formed on the top conductive plug Vt of the interconnect structure 13. The organic layer 15 is formed on the bottom electrode 14. The bottom electrode 14 is an ultra-thin electrode relative to the organic layer 15; this is to avoid coating scattering of the organic layer 15.

[0003] Please see Figure 1B , Figure 1B This image shows a transmission electron microscopy (TEM) image of the top conductive plug Vt, bottom electrode 14, and dielectric layer ILD in a known organic photodiode, viewed in a vertical cross-section. In the case where the bottom electrode 14 is an ultrathin electrode relative to the organic layer 15, a void VD is formed between the bottom electrode 14 and the top conductive plug Vt of the interconnect structure 13 it contacts below. This is because, during the etching process that forms the top conductive plug Vt, the vertical profile of the top conductive plug Vt formed by the retreat etching has a groove that is lower than the surrounding dielectric layer ILD, such as... Figure 1B The dotted broken line in the image illustrates this.

[0004] The known voids in the organic photodiode 10 cause poor contact between the bottom electrode 14 and the top conductive plug Vt below it, resulting in unstable electrical characteristics of the organic photodiode 10.

[0005] In view of this, the present invention addresses the shortcomings of the prior art by proposing an innovative organic photodiode and its manufacturing method. Summary of the Invention

[0006] In one viewpoint, the present invention provides an organic photodiode comprising: an element formed in a substrate; an interconnect structure formed above the substrate and connected to the element; a bottom electrode formed on the interconnect structure and connected to a bevel plate of the interconnect structure, wherein the bottom electrode is entirely formed within the upper surface of the bevel plate, and wherein the contact area between the bottom electrode and the bevel plate is on the same order of magnitude as the pixel size, and the upper surface of the bevel plate extends beyond the pixel size; and an organic layer formed on the bottom electrode and connected to the bottom electrode.

[0007] From another perspective, the present invention provides a method for manufacturing an organic photodiode, comprising the following steps: First, forming an element in a substrate; then, forming an interconnect structure on the substrate and connecting it to the element; next, forming a bottom electrode on the interconnect structure and connecting it to a bevel plate of the interconnect structure, wherein the bottom electrode is completely formed within the upper surface of the bevel plate, and wherein the contact area between the bottom electrode and the bevel plate is on the same order of magnitude as the pixel size, while the upper surface of the bevel plate extends beyond the pixel size; and then, forming an organic layer on the bottom electrode and connecting it to the bottom electrode.

[0008] In a preferred embodiment, the bevel plate is connected to a top conductive plug of the interconnect structure, wherein the top conductive plug is connected to a top metal layer of the interconnect structure, and the bevel plate has a lower surface opposite to the upper surface, wherein the upper surface is connected to the bottom electrode and the bottom electrode is located in the vertical projection area of ​​the upper surface, and the lower surface is connected to the top conductive plug.

[0009] In a preferred embodiment, the angle between one of the inclined sidewalls of the beveled plate and the normal to the lower surface ranges from 0 degrees to 45 degrees.

[0010] In a preferred embodiment, the bottom electrode is made of at least one of the following: titanium nitride, titanium, aluminum, tantalum nitride, tantalum, chromium, silver, and gold.

[0011] In a preferred embodiment, a readout circuit is further formed on the substrate. The readout circuit includes at least one semiconductor element and a readout interconnect structure. The semiconductor element is electrically connected to the readout interconnect structure, and the readout circuit is coupled to the organic photodiode to read out a photoelectric signal generated by the organic photodiode.

[0012] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features and effects achieved by the present invention. Attached Figure Description

[0013] Figure 1A This shows a cross-sectional schematic diagram of a known organic photodiode.

[0014] Figure 1B This displays a transmission electron microscopy (TEM) image of the top conductive plug Vt, bottom electrode 14, and dielectric layer ILD in a vertical cross-section of a known organic photodiode.

[0015] Figure 2 This is a cross-sectional schematic diagram of an organic photodiode according to an embodiment of the present invention.

[0016] Figure 3A and Figure 3B The figures show cross-sectional and top views of the bottom electrode, the beveled plate, and the top conductive bolt, respectively, according to an embodiment of the present invention.

[0017] Figures 4A-4E This is a schematic flowchart illustrating a method for manufacturing an organic photodiode according to an embodiment of the present invention.

[0018] Explanation of the number in the picture

[0019] 10, 20: Organic photodiodes

[0020] 11, 21: substrate

[0021] 12, 22: Components

[0022] 13, 23, 33: Interconnection structure

[0023] 14, 24: Bottom electrode

[0024] 15, 25: Organic layer

[0025] 30: Readout Circuit

[0026] 32: Semiconductor components

[0027] ILD: Dielectric layer

[0028] M1, M2, M3, M4, M5: Metal layers

[0029] Sb: Lower surface

[0030] St: Upper surface

[0031] Tm: Top metal layer

[0032] Tp: Angled plate

[0033] V: Conductive plug

[0034] VD: Void

[0035] Vt: Top conductive plug

[0036] Ws: Conical sidewall

[0037] α: Angle Detailed Implementation

[0038] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings. The drawings in this invention are illustrative and are primarily intended to illustrate process steps and the hierarchical relationship between layers; shapes, thicknesses, and widths are not drawn to scale.

[0039] Figure 2 This is a cross-sectional schematic diagram showing an organic photodiode according to an embodiment of the present invention. Figure 2 As shown, the organic photodiode 20 of the present invention includes: an element 22, an interconnect structure 23, a bottom electrode 24, and an organic layer 25. The element 22 is formed in a substrate 21. It should be noted that the element 22 being formed in the substrate 21 does not limit the element 22 to being formed only inside the substrate 21; it also includes the gate structure on the substrate 21. The interconnect structure 23 is formed above the substrate 21 and connected to the element 22. The interconnect structure 23 includes multiple metal layers M1-M4 (shown as four layers in this embodiment, but according to the present invention, the number of metal layers is not limited to four) and multiple conductive plugs V. The conductive plugs V electrically connect the multiple metal layers M1-M4 to the element 22. Furthermore, the aforementioned structures are insulated from each other by a dielectric layer ILD, except for the connected portions. The multiple metal layers M1-M4 include, for example, but not limited to, metal layers made of aluminum, copper, aluminum-copper alloys, or other conductive materials. The conductive plugs V include, for example, but not limited to, conductive plugs made of tungsten, polysilicon, aluminum, copper, aluminum-copper alloys, or other conductive materials. In a preferred embodiment, the dielectric layer ILD includes a silicon dioxide layer. A bottom electrode 24 is formed on the interconnect structure 23 and connected to the bevel plate Tp of the interconnect structure 23. The bottom electrode 24 is entirely formed within the vertical projection region of the upper surface of the bevel plate Tp, and the contact area between the bottom electrode 24 and the bevel plate Tp is on the same order of magnitude as the pixel size, while the upper surface of the bevel plate Tp extends beyond the pixel size. An organic layer 25 is formed on the bottom electrode 24 and connected to the bottom electrode 24.

[0040] It should be noted that pixel size refers to the size of a single pixel in a bit-based imaging device, such as a camera sensor or display. Pixel size is crucial in sensors because it affects the amount of light each pixel can capture, thus influencing the sensor's sensitivity and image quality. Pixel size is well-known to those skilled in the art and will not be described in detail here. The projected area of ​​the pixel size in the vertical direction is essentially equivalent to the projected area of ​​the bottom electrode 24 in the vertical direction.

[0041] When the organic photodiode 20 according to the present invention is fabricated using a CMOS process, a readout circuit 30 is further formed on the substrate 21. The readout circuit 30 includes at least one semiconductor element 32 and an interconnect structure 33. The interconnect structure 33 includes multiple metal layers M1-M5 (shown as five layers in this embodiment, but the number of metal layers is not limited to five according to the present invention) and multiple conductive plugs V. The multiple conductive plugs V are electrically connected to the multiple metal layers M1-M5 and the semiconductor element 32, respectively. Furthermore, the aforementioned structures are insulated from each other except for the connecting portions by a dielectric layer ILD. The multiple metal layers M1-M5 include, for example, but not limited to, aluminum, copper, aluminum-copper alloys, or other conductive metal layers. The conductive plugs V include, for example, but not limited to, tungsten, polysilicon, aluminum, copper, aluminum-copper alloys, or other conductive conductive plugs. In a preferred embodiment, the dielectric layer ILD includes a silicon dioxide layer.

[0042] In this embodiment, the substrate 21 is, for example, but not limited to, a silicon substrate. Figure 2 As shown, in this embodiment, each metal layer M1 to M4 in the interconnect structure 23 and each metal layer M1 to M4 in the interconnect structure 33 are formed by the same metal deposition process step.

[0043] Please continue reading. Figure 2 Compared to the prior art organic photodiode 10, in the organic photodiode 20 of the present invention, the bottom electrode 24 is formed on the interconnect structure 23 and connected to the bevel plate Tp of the interconnect structure 23, wherein the bottom electrode 24 is completely formed within the vertical projection area of ​​the bevel plate Tp. It should be noted that the term "vertical projection area" refers to the area covered by the projection of the bevel plate Tp in the vertical direction, such as... Figure 3A The area shown is a diagonal region without an outer boundary.

[0044] According to the present invention, the bottom electrode 24 is connected to the bevel plate Tp and is completely located within the vertical projection area of ​​the bevel plate Tp, thus solving the problem in the prior art where a gap VD is formed between the bottom electrode 14 and the top conductive plug Vt of the interconnect structure 13, resulting in poor contact and unstable electrical characteristics of the organic photodiode 10. In other words, because the bottom electrode 24 of the present invention is completely formed within the area covered by the vertical projection of the bevel plate Tp, the problem of a gap VD forming between the bottom electrode 14 and the top conductive plug Vt in the prior art does not occur. More specifically, in the prior art, during the CMP and / or etching process of forming the top conductive plug Vt, the vertical shape (vertical profile) of the top conductive plug Vt formed by the recessed CMP and / or etching process has a lower groove relative to the surrounding dielectric layer ILD, i.e., there is a height difference (step height) between the dielectric layer ILD and the top conductive plug Vt, resulting in a gap problem when the bottom electrode 14 is formed on the top conductive plug Vt in the prior art.

[0045] It should be noted that a top conductive plug refers to a conductive plug that has no other conductive plugs above it in the vertical direction. Similarly, a top metal layer refers to a metal layer that has no other metal layer above it in the vertical direction.

[0046] In a preferred embodiment, in the organic photodiode 20, the material of the bottom electrode 24 includes at least one of the following: titanium nitride, titanium, aluminum, tantalum nitride, tantalum, chromium, silver, and gold.

[0047] refer to Figure 3A and Figure 3B , Figure 3A and Figure 3B A cross-sectional view and a top view of the bottom electrode 24, the bevel plate Tp, and the top conductive plug Vt according to an embodiment of the present invention are shown respectively. In a preferred embodiment, in the organic photodiode 20, the top conductive plug Vt is connected to the top metal layer Tm of the interconnect structure 23 (in this embodiment, metal layer M4 serves as the top metal layer Tm), and the bevel plate Tp has an upper surface St and a lower surface Sb opposite to the upper surface St, wherein the upper surface St is connected to the bottom electrode 24 and the bottom electrode 24 is located in the vertical projection region of the upper surface St, while the lower surface Sb is connected to the top conductive plug Vt.

[0048] In a preferred embodiment, the angle α between the inclined sidewall Ws of the beveled plate Tp and the normal to the lower surface Sb ranges from 0 degrees to 45 degrees. It should be noted that the inclined sidewall Ws is the sidewall of the beveled plate Tp. It should also be noted that in one embodiment, both the upper surface St and the lower surface Sb are flat. In another embodiment, the lower surface Sb may not be flat. The lower surface Sb can be of other shapes than flat, including rough surfaces, irregular planar surfaces, circular surfaces, etc.

[0049] like Figure 3B As shown, in the organic photodiode 20 according to the present invention, as shown in the top view, the bottom electrode 24 is completely connected to the bevel plate Tp and formed in the vertical projection area of ​​the bevel plate Tp, indicating that the bottom electrode 24 is completely located within the area covered by the vertical projection of the bevel plate Tp.

[0050] Figures 4A to 4E A schematic flowchart illustrating a method for manufacturing an organic photodiode 20 according to an embodiment of the present invention is shown. Figures 4A-4E A method for manufacturing the organic photodiode 20 according to the present invention can be described. For example... Figure 4AAs shown, firstly, element 22 is formed in substrate 21, and simultaneously, at least one semiconductor element 32 of readout circuit 30 is formed on substrate 21. Then, interconnect structure 23 is formed on substrate 21 and connected to element 22. Interconnect structure 33 is also formed concurrently with interconnect structure 23. Interconnect structure 23 includes multiple metal layers M1-M4 (shown as four layers in this embodiment, but the number of multiple metal layers is not limited to four according to the invention) and multiple conductive plugs V. The conductive plugs V are electrically connected to the multiple metal layers M1-M4 and element 22, respectively. In addition to the connection portions between element 22, multiple metal layers M1-M4, and conductive plugs V, an dielectric layer ILD is provided for insulation. Next, for example, a top conductive plug via Vd is formed by an etching process step.

[0051] Next, as Figure 4B As shown, for example, the beveled plate through-hole Vp is formed through an etching process. Then, as... Figure 4C As shown, after filling the top conductive plug via Vd and the bevel plate via Vp with conductive material, the surface of the bevel plate Tp is planarized, for example, by a chemical mechanical polishing (CMP) process, and the top conductive plug Vt and the bevel plate Tp are formed. In this embodiment, for example, the top conductive plug Vt and the bevel plate Tp are formed using a dual damascene process as described above. In another embodiment, a single damascene process or a deposition process and an etching process can also be used to form the top conductive plug Vt and the bevel plate Tp. Next, a metal layer M5 is formed on the substrate 21 to form the interconnect structure 33.

[0052] Then, as Figure 4D As shown, a bottom electrode 24 is formed. The bottom electrode 24 is formed above the interconnect structure 23 and connected to the bevel plate Tp of the interconnect structure 23. The bottom electrode 24 is entirely formed within the vertical projection area of ​​the upper surface St of the bevel plate Tp, and the contact area between the bottom electrode 24 and the bevel plate Tp is on the same order of magnitude as the pixel size, while the upper surface St of the bevel plate Tp exceeds (i.e., is greater than) the pixel size. Then, as... Figure 4E As shown, the organic layer 25 is formed on the bottom electrode 24 and connected to the bottom electrode 24.

[0053] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the scope of the invention. Various equivalent changes can be conceived by those skilled in the art within the same spirit of the invention. For example, other process steps or structures, such as a critical voltage adjustment region, can be added without affecting the main characteristics of the component; furthermore, lithography is not limited to photomask technology and may also include electron beam lithography. All of these can be deduced by analogy from the teachings of the present invention. Furthermore, the described embodiments are not limited to individual application and can be combined, for example, but not limited to using two embodiments together. Therefore, the scope of the present invention should cover the above and all other equivalent changes. Moreover, any embodiment of the present invention does not necessarily achieve all the objectives or advantages; therefore, no claim should be limited thereto.

Claims

1. An organic photodiode, comprising: A component is formed in a substrate; An interconnect structure is formed on the substrate and connected to the component; A bottom electrode is formed on the interconnect structure and connected to a beveled plate of the interconnect structure, wherein the bottom electrode is entirely formed within the upper surface of the beveled plate, and wherein the contact area between the bottom electrode and the beveled plate is on the same order of magnitude as the pixel size, while the upper surface of the beveled plate extends beyond the pixel size; and An organic layer is formed on the bottom electrode and connected to the bottom electrode.

2. The organic photodiode as described in claim 1, wherein, The bevel plate is connected to a top conductive plug of the interconnect structure, wherein the top conductive plug is connected to a top metal layer of the interconnect structure, and the bevel plate has a lower surface opposite to the upper surface, wherein the upper surface is connected to the bottom electrode and the bottom electrode is located in the vertical projection area of ​​the upper surface, and the lower surface is connected to the top conductive plug.

3. The organic photodiode as described in claim 2, wherein, The angle between one of the inclined sidewalls of the beveled plate and the normal to the lower surface ranges from 0 degrees to 45 degrees.

4. The organic photodiode as described in claim 1, wherein, The bottom electrode is made of at least one of the following materials: titanium nitride, titanium, aluminum, tantalum nitride, tantalum, chromium, silver, and gold.

5. The organic photodiode as described in claim 1, wherein, A readout circuit is further formed in the substrate. The readout circuit includes at least one semiconductor element and a readout interconnect structure. The semiconductor element is electrically connected to the readout interconnect structure, and the readout circuit is coupled to the organic photodiode to read out a photoelectric signal generated by the organic photodiode.

6. A method for manufacturing an organic photodiode, comprising: First, an element is formed in a substrate; Subsequently, an interconnect structure is formed on the substrate and connected to the component; Next, a bottom electrode is formed on the interconnect structure and connected to a beveled plate of the interconnect structure, wherein the bottom electrode is completely formed within the upper surface of the beveled plate, and wherein the contact area between the bottom electrode and the beveled plate is on the same order of magnitude as the pixel size, while the upper surface of the beveled plate extends beyond the pixel size; and Then, an organic layer is formed on the bottom electrode and connected to the bottom electrode.

7. The method for manufacturing an organic photodiode as described in claim 6, wherein, The bevel plate is connected to a top conductive plug of the interconnect structure, wherein the top conductive plug is connected to a top metal layer of the interconnect structure, and the bevel plate has a lower surface opposite to the upper surface, wherein the upper surface is connected to the bottom electrode and the bottom electrode is located in the vertical projection area of ​​the upper surface, and the lower surface is connected to the top conductive plug.

8. The method for manufacturing an organic photodiode as described in claim 7, wherein, The angle between one of the inclined sidewalls of the beveled plate and the normal to the lower surface ranges from 0 degrees to 45 degrees.

9. The method for manufacturing an organic photodiode as described in claim 6, wherein, The bottom electrode is made of at least one of the following materials: titanium nitride, titanium, aluminum, tantalum nitride, tantalum, chromium, silver, and gold.

10. The method for manufacturing an organic photodiode as described in claim 6, wherein, It also includes: forming a readout circuit on the substrate, the readout circuit including at least one semiconductor element and a readout interconnect structure, wherein the semiconductor element is electrically connected to the readout interconnect structure, and the readout circuit is coupled to the organic photodiode for reading out a photoelectric signal generated by the organic photodiode.

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