Optoelectronic device and method for manufacturing the same

Abstract

An optoelectronic device (1) includes a substrate (2) having a photosensitive structure (4) and a dielectric layer (5) on a main surface (3) of the substrate (2), the dielectric layer (5) having a top surface (6) facing away from the substrate (2). At least one wiring layer (7) is arranged at some positions in the dielectric layer (5), and at least one contact area (9) is formed by a part of the at least one wiring layer (7). An opening (11) is formed at the top surface (6) of the dielectric layer (5), and the opening (11) extends towards the contact area (9). An optical element (12) is arranged above the photosensitive structure (4) and on the top surface (6) of the dielectric layer (5), and an optical filter (13) is arranged on the top surface (6) of the dielectric layer (5), the optical filter (13) being conductive, covering a part of the optical element (12) and being in electrical contact with the contact area (9). In addition, a method for manufacturing the optoelectronic device (1) is provided.

Description

Technical Field

[0001] The present application relates to optoelectronic devices and methods for manufacturing optoelectronic devices. Background Art

[0002] Many optoelectronic devices are suitable for detecting electromagnetic radiation within a specific wavelength range. To prevent electromagnetic radiation leakage and crosstalk between individual photosensitive structures within the optoelectronic device, specific regions of the sensor chip are often covered by optical filters. The optical filters are provided to absorb unwanted electromagnetic radiation at positions where the sensor chip is optically ineffective. In addition, the optical filters prevent or reduce the reflectivity of the surface of the sensor chip. This is also important because the reflected electromagnetic radiation may be scattered back and create so-called "ghost images" on adjacent photosensitive structures. Therefore, the integration of the optical filters improves the optoelectronic device in terms of optical characteristics.

[0003] However, by integrating the optoelectronic device into an electronic system, such as an integrated dense-packaged camera system in a mobile device, the optoelectronic device is very close to other electronic components. The electronic components can generate electromagnetic fields, which may cause electromagnetic interference (EMI). This in turn can lead to the deterioration of individual devices and the degradation of system performance. In addition, each electronic device is vulnerable to damage caused by electrostatic discharge (ESD). Summary of the Invention

[0004] An object of the present invention is to provide an optoelectronic device having improved optical and electrical characteristics. Another object of the present invention is to provide a method for manufacturing an optoelectronic device having improved optical and electrical characteristics.

[0005] This object is achieved by the independent claims. Further embodiments and variants result from the dependent claims. Unless otherwise stated, the above definitions also apply to the following description.

[0006] In one embodiment, the optoelectronic device includes a substrate, which may include a semiconductor material, such as silicon (Si). The substrate can have a main extension plane. The optoelectronic device can be a complementary metal oxide semiconductor (CMOS) device. The optoelectronic device can be arranged in a housing.

[0007] The optoelectronic device further comprises a photosensitive structure in the substrate, which can be, for example, a photodiode or an array of photodiodes. The photosensitive structure can also comprise a phototransistor or an array of phototransistors or any other suitable detection element for detecting electromagnetic radiation. The photosensitive structure can be arranged at the main surface of the substrate. The photosensitive structure can be surrounded by the substrate at the lateral surfaces of the photosensitive structure. This means that the photosensitive structure can be surrounded by the substrate in a lateral direction traveling parallel to the main extension plane of the substrate. The top side of the photosensitive structure can be free of the substrate. The photosensitive structure can be configured to detect electromagnetic radiation entering the optoelectronic device at the top side of the optoelectronic device. The wavelength of the electromagnetic radiation can range from the ultraviolet (UV) spectrum to the mid-infrared (MIR) spectrum.

[0008] The optoelectronic device further comprises a dielectric layer on the main surface of the substrate, the dielectric layer having a top surface facing away from the substrate. The dielectric layer is arranged above the substrate. The dielectric layer can be, for example, a doped or undoped silicon oxide (SiO2) layer. The dielectric layer can be formed by several deposition steps.

[0009] The optoelectronic device further comprises at least one wiring layer arranged at some positions in the dielectric layer. The at least one wiring layer comprises a metal, such as aluminum (Al). The at least one wiring layer can be electrically connected to different functional parts in the substrate, such as the gates of transistors in an integrated circuit (IC). The wiring layer can also be in electrical contact with the photosensitive structure. The wiring layer is removed in a vertical direction above the photosensitive structure, wherein the vertical direction extends perpendicular to the main extension plane of the substrate. This means that in the region above the photosensitive structure, the dielectric layer is free of the wiring layer. Thus, the electromagnetic radiation entering the optoelectronic device is not blocked by the at least one wiring layer and can reach the photosensitive structure.

[0010] The optoelectronic device further comprises at least one contact area formed by a part of the at least one wiring layer. The at least one contact area can be used for electrically contacting the optoelectronic device. On the side facing away from the substrate, the contact area is free of the dielectric layer. The contact area is an area at the surface of the wiring layer. The surface of the wiring layer can be larger than the contact area.

[0011] The optoelectronic device further comprises an opening at the top surface in the dielectric layer, the opening extending towards the contact area. The opening is formed as a trench extending in a vertical direction within the dielectric layer. The opening can have the same extent as the contact area in the lateral direction. Thus, the optoelectronic device can be electrically contacted from the top surface of the dielectric layer. The contact area can exhibit a constant potential, such as ground potential.

[0012] Furthermore, the optoelectronic device comprises an optical element arranged above the photosensitive structure, on the top surface of the dielectric layer. The optical element is arranged above the photosensitive structure in a vertical direction. The optical element can be adapted to direct electromagnetic radiation of a specific wavelength or within a specific wavelength range towards the photosensitive structure.

[0013] In addition, the optoelectronic device includes an optical filter disposed on the top surface of the dielectric layer. The optical filter is conductive and is in electrical contact with the contact region. The optical filter also covers a portion of the optical element. In this way, the optical filter provides an aperture towards the photosensitive structure. The optical filter can exhibit a low angular dependence on incident electromagnetic radiation. In the wavelength range from 300 nm to 1200 nm, the optical filter can have a reflectivity of at most 0.2. Preferably, in the wavelength range from 300 nm to 1200 nm, the optical filter can have a reflectivity of at most 0.03. Due to its optical properties, the optical filter absorbs unwanted electromagnetic radiation and prevents or reduces reflection on the surface of the optoelectronic device. In addition, due to its electrical properties, the optical filter provides shielding against EMI and protection against ESD.

[0014] The optical filter improves the optical properties of the optoelectronic device. On the one hand, this is because the optical filter prevents or reduces the reflection of electromagnetic radiation on the surface of the optoelectronic device. In the absence of the optical filter, the reflected electromagnetic radiation may be reflected back in an uncontrolled manner (e.g., through the housing of the optoelectronic device).

[0015] On the other hand, the optical filter also absorbs electromagnetic radiation at positions where the optoelectronic device is optically ineffective. This means that at positions where there is no photosensitive structure under the substrate, the electromagnetic radiation is blocked from entering the optoelectronic device. Therefore, the electromagnetic radiation cannot enter the optoelectronic device at positions where the electromagnetic radiation propagates and reflects in an uncontrolled manner.

[0016] In this way, leakage of electromagnetic radiation is prevented. In addition, optical crosstalk between individual photosensitive structures is prevented. This in turn improves the signal-to-noise ratio, thereby providing the accuracy of the optoelectronic device.

[0017] The optical filter also improves the electrical properties of the optoelectronic device. This is because the optical filter is electrically connected to the contact region, which can have a fixed potential, such as ground potential. Therefore, the optoelectronic device is protected from ESD because the charge can be discharged without causing damage to the electronic components of the device.

[0018] In addition, since it is conductive, the optical filter shields the optoelectronic device from electromagnetic fields and isolates the optoelectronic device from its surroundings. In this way, the optical filter provides protection against interfering signals such as radio frequency (RF) signals.

[0019] In one embodiment, the optical filter covers the bottom portion, sidewalls, and edges of the opening at the top surface of the dielectric layer. The bottom portion of the opening is the portion of the opening facing the contact region. The sidewalls of the opening extend perpendicular or transverse to the main extension plane of the substrate. The edges of the opening are disposed at the top surface of the dielectric layer. The edges define the opening. The optical filter can be in direct contact with the contact region. In this way, the optical filter is electrically connected to the contact region. By electrically connecting the optical filter to a fixed constant potential via the contact region, the optical filter provides ESD protection for the optoelectronic device. The optical filter also provides EMI shielding for the optoelectronic device.

[0020] In another embodiment, the optoelectronic device further includes a spacer structure that covers the bottom portion, sidewalls, and edges of the opening at the top surface of the dielectric layer. The spacer structure is in direct contact with the contact region and in direct contact with the optical filter. In this way, the spacer structure electrically connects the contact region to the optical filter. When the spacer structure is used, the optical filter can be thin in the vertical direction because the optical filter does not have to cover the edges of the dielectric layer opening. A thin layer has less internal stress compared to a thick layer and can be more easily patterned. Therefore, if there are limitations regarding mechanical stress or special requirements for patterning the optical filter, it can be advantageous to use a thin layer to implement the optical filter.

[0021] In one embodiment, the spacer structure includes a stack of at least two conductive layers. For example, the spacer structure can include a first conductive layer, a second conductive layer, and a third conductive layer. The first conductive layer can include Al. The second conductive layer can include titanium (Ti). The third conductive layer can include indium tin oxide (ITO). However, the spacer structure is not limited to including these materials and can include any other suitable materials. The advantage of the layer stack including Al, Ti, and ITO is that Al has good conductivity and is compatible with CMOS processing. The Ti layer is provided as a buffer layer and provides good adhesion of the ITO layer. The ITO layer prevents corrosion of the Al layer. The conductive layers are disposed on top of each other. The second conductive layer covers the first conductive layer. The third conductive layer covers the second conductive layer. The second conductive layer can be disposed vertically between the first conductive layer and the third conductive layer. The first conductive layer can be disposed closer to the substrate than the second and third conductive layers.

[0022] In one embodiment, the optical filter includes a conductive layer. The conductive layer may include, for example, Al. However, the conductive layer of the optical filter is not limited to an Al layer and may include any other suitable conductive material. The optical filter further includes an anti-reflection coating over the conductive layer. This means that the anti-reflection coating is disposed on the side of the conductive layer facing away from the substrate. The anti-reflection coating includes, for example, a stack of alternating dielectric layers and metal layers. The anti-reflection coating may also include a stack of alternating dielectric layers. The anti-reflection coating may also include a stack of alternating nitride layers and metal layers. The number and thickness of the alternating layers can vary according to the application.

[0023] The conductive layer of the optical filter is provided for the conductivity of the optical filter and for absorbing unwanted electromagnetic radiation. The anti-reflection coating of the optical filter is provided for reducing the reflectivity of the surface of the optoelectronic device facing the incoming electromagnetic radiation. The anti-reflection coating exhibits a low angular dependence on the incident electromagnetic radiation. For example, in the wavelength range from 300 nm to 1200 nm, the reflectivity of the anti-reflection coating is less than 0.2. Preferably, in the wavelength range from 300 nm to 1200 nm, the anti-reflection coating can have a reflectivity of at most 0.03.

[0024] In another embodiment, the optical filter includes a conductive black chromium coating. The black chromium coating is a layer disposed on the top side of the optoelectronic device. The black chromium coating includes chromium. For example, in the wavelength range from 300 nanometers to 1200 nanometers, the reflectivity of the black chromium coating is generally less than 5%.

[0025] The conductive black chromium coating is provided for the conductivity of the optical filter and for absorbing unwanted electromagnetic radiation and for reducing the reflectivity of the surface of the optoelectronic device facing the incoming electromagnetic radiation.

[0026] In another embodiment, the optical filter includes a conductive layer and a black chromium layer over the conductive layer. The conductive layer may include, for example, metallic chromium (Cr) or any other suitable material, such as Al, Ti, or silver (Ag).

[0027] The conductive layer is provided for the conductivity of the optical filter and for absorbing unwanted electromagnetic radiation. The black chromium layer is provided for further absorbing electromagnetic radiation and for reducing the reflectivity of the surface of the optoelectronic device facing the incoming electromagnetic radiation.

[0028] In another embodiment, the optical filter includes a conductive organic color coating. The organic color coating is a layer disposed on the top side of the optoelectronic device. The organic color coating includes an organic material, such as a resist. For example, in the wavelength range from 300 nanometers to 1200 nanometers, the reflectivity of the organic color coating is less than 0.2. Preferably, in the wavelength range from 300 nanometers to 1200 nanometers, the organic color coating can have a reflectivity of at most 0.03. The conductivity of the organic color coating can be achieved by adding carbon nanotubes or carbon black or by adding a conductive polymer such as PEDOT:PSS.

[0029] The conductive organic color coating is provided for the conductivity of the optical filter and for absorbing unwanted electromagnetic radiation and reducing the reflectivity of the surface of the optoelectronic device facing the incoming electromagnetic radiation.

[0030] In another embodiment, the optical filter includes a conductive layer, such as a layer including Al, and an organic color coating above the conductive layer.

[0031] The conductive layer is provided for the conductivity of the optical filter and for absorbing unwanted electromagnetic radiation. The organic color coating is provided for further absorbing electromagnetic radiation and reducing the reflectivity of the surface of the optoelectronic device facing the incoming electromagnetic radiation.

[0032] In another embodiment, the optoelectronic device includes a passivation layer disposed at some positions in the dielectric layer. The passivation layer can include, for example, silicon nitride (Si3N4). The passivation layer is disposed above at least one wiring layer. This means that, in the vertical direction, the wiring layer is disposed between the passivation layer and the substrate. In the vertical direction, the passivation layer is removed above the photosensitive structure. This means that in the region above the photosensitive structure, the dielectric layer does not have a passivation layer. In this way, the electromagnetic radiation entering the optoelectronic device is not blocked by the passivation layer and can reach the photosensitive structure. In addition, unwanted interference of the electromagnetic radiation on the passivation layer is prevented. As described above, by forming an opening in the dielectric layer, the passivation layer is also removed in the region above the contact area.

[0033] By using the passivation layer, the optoelectronic device becomes more resistant to the environment. For example, the optoelectronic device becomes more scratch-resistant or more moisture-resistant.

[0034] In another embodiment, the optoelectronic device includes an IC in the substrate. The IC can be disposed in the substrate, next to the photosensitive structure. This means that in the lateral direction traveling parallel to the main extension plane of the substrate, the IC can be adjacent to the photosensitive structure. The IC can also be disposed vertically below the photosensitive structure in the substrate.

[0035] By adopting an IC, the photosensitive structure can be controlled. The electrical signals from the photosensitive structure can be effectively processed. In addition, the optoelectronic device can communicate with other electronic components via the IC.

[0036] In another embodiment, the optical element of the optoelectronic device is an interference filter. The interference filter can include a stack of alternating dielectric layers and metal layers. The interference filter can be implemented as, for example, a long-pass filter or a band-pass filter.

[0037] The purpose of using the interference filter is to transmit only a specific wavelength or a specific wavelength range to the photosensitive structure. In this way, the signal-to-noise ratio of the optoelectronic device can be improved.

[0038] In another embodiment, the photosensitive structure is a single photodiode or an array of photodiodes. In the case of an array of photodiodes, the array can have a rectangular shape. In the array, the photodiodes can be arranged at the lattice points of a lattice. The lattice can be linear or two-dimensional. The photodiodes in the array can be arranged side by side with each other. This means that, in the lateral direction, the photodiodes can be adjacent to each other. As described above, each photodiode in the photodiode array can be arranged within the optoelectronic device. This means that there are no wiring layers and passivation layers in the region of the dielectric layer above each photodiode, and there is an optical element on the top surface of the dielectric layer above each photodiode, and the optical filter forms a hole towards each photodiode. By using an array of photodiodes, applications such as imaging become possible.

[0039] In another embodiment, the optoelectronic device is integrated in an electronic device. The electronic device can be, for example, a camera system. The camera system can be used to image a scene in a desired wavelength range. For example, the camera system can be used to image in the visible spectrum. Advantageously, the camera system can be arranged very close to other electronic components because, due to the EMI shielding characteristics of the optical filter, the camera system is more resistant to problems related to electromagnetic interference. The optoelectronic device is not limited to being integrated in a camera system, but can be integrated in any electronic device, such as an electromagnetic radiation sensor device.

[0040] In addition, a method for manufacturing an optoelectronic device is provided. All the features disclosed for the optoelectronic device are also disclosed for the method for manufacturing the optoelectronic device, and vice versa.

[0041] The method for manufacturing an optoelectronic device includes providing a substrate and forming a photosensitive structure in the substrate. In the case where the photosensitive structure is a photodiode, the photodiode can be realized by ion implantation. A dielectric layer is deposited on the substrate, and the dielectric layer has a top surface facing away from the substrate. The deposition of the dielectric layer can include several deposition steps. For example, the deposition can be achieved by chemical vapor deposition (CVD). The dielectric layer can be in direct contact with the substrate.

[0042] At least one wiring layer is deposited and disposed at some positions within the dielectric layer. This means that a portion of the dielectric layer is deposited on the substrate and the wiring layer is deposited on the dielectric layer. Thereafter, another deposition step for depositing the dielectric layer is carried out such that the wiring layer is disposed at some positions within the dielectric layer. The wiring layer can be deposited by a sputtering process and patterned by an etching process.

[0043] The wiring layer forms contact regions at some positions. This means that a portion of the wiring layer, namely the contact regions, is configured for electrical contact. The wiring layer can be removed above the photosensitive structure.

[0044] An opening is formed at the top surface of the dielectric layer, and the opening extends towards the contact regions. The opening is formed by removing the material disposed above the contact regions. The opening can be formed by etching.

[0045] An optical element is deposited on the dielectric layer, and the optical element is disposed above the photosensitive structure in the vertical direction. The optical element can be deposited, for example, by CVD, atomic layer deposition (ALD) or physical vapor deposition (PVD). The patterning of the optical element can be accomplished by etching.

[0046] An optical filter is deposited. The optical filter can be deposited at some positions on the top surface of the dielectric layer and on a portion of the optical element. Depending on the material used for the optical filter, the deposition technique can include CVD, ALD, PVD, spin coating or sputtering process. The patterning of the optical filter can be accomplished by etching, for example.

[0047] In one embodiment of the method for manufacturing an optoelectronic device, the optical filter is disposed at some positions on the top surface of the dielectric layer, on a portion of the optical element and in the opening of the dielectric layer, and the optical filter covers the bottom portion, sidewalls and edges of the opening at the top surface of the dielectric layer. Thus, the optical filter is electrically connected to the contact regions. By electrically connecting the optical filter to a fixed constant potential via the contact regions, the optical filter provides ESD protection for the optoelectronic device.

[0048] In another embodiment of the method for manufacturing an optoelectronic device, a spacer structure is deposited into the opening of the dielectric layer and on the contact regions before depositing the optical filter, and the spacer structure covers the bottom portion, sidewalls and edges of the opening at the top surface of the dielectric layer. The spacer structure is in direct contact with the contact regions. The deposition technique of the spacer structure depends on the material used. For example, the deposition technique can include sputtering techniques. The material layer of the spacer structure can be patterned by etching. The optical filter is deposited after depositing the spacer structure. When a spacer structure is used, the optical filter can be thin in the vertical direction because the optical filter does not have to cover the edges of the opening in the dielectric layer.

[0049] In another embodiment of the method for manufacturing an optoelectronic device, an optical filter is disposed at some positions on the top surface of a dielectric layer, on a part of an optical element, and on a part of a spacer structure. In this way, the optical filter is electrically connected to a contact region. By electrically connecting the optical filter to a fixed constant potential via the contact region, the optical filter provides ESD protection for the optoelectronic device. Description of the Drawings

[0050] The following description of the drawings may further illustrate and explain exemplary embodiments. Components that are functionally identical or have the same function are denoted by the same reference numerals. The same or substantially the same components are described only for the drawings in which the reference numerals first appear. Their description does not need to be repeated in the consecutive drawings.

[0051] Figure 1a A cross-section of an example of an optoelectronic device using an optical filter is shown.

[0052] In Figure 1b a top view of an example of an optoelectronic device using an optical filter is shown.

[0053] Figure 2a A cross-section of an exemplary embodiment of an optoelectronic device using an optical filter in electrical contact with a contact region is shown.

[0054] Figure 2b A cross-section of another exemplary embodiment of an optoelectronic device using an optical filter in electrical contact with a contact region is shown.

[0055] In Figure 2c a top view of an embodiment of an optoelectronic device using an optical filter in electrical contact with a contact region is shown.

[0056] Figure 2d A top view of an embodiment of an optoelectronic device including an array of photosensitive structures is shown.

[0057] Figure 3a A cross-section of an exemplary embodiment of an optoelectronic device using a spacer structure to connect a contact region to an optical filter is shown.

[0058] Figure 3b A cross-section of another exemplary embodiment of an optoelectronic device using a spacer structure to connect a contact region to an optical filter is shown.

[0059] Figure 4 A schematic diagram of an electronic device including an optoelectronic device is shown. Detailed Description

[0060] In Figure 1aA cross-sectional view of an example (not an embodiment) of the optoelectronic device 1 is shown. The feature to be emphasized here is the optical filter 13, which covers a part of the top surface 6 of the dielectric layer 5 and a part of the optical element 12. The optical filter 13 does not cover the bottom part 14, the side wall 15, and the edge 16 of the opening 11 at the top surface 6 of the dielectric layer 5. Therefore, the optical filter 13 is not electrically connected to a fixed potential. Therefore, the optical filter 13 cannot provide EMI shielding or ESD protection.

[0061] Figure 1b is shown Figure 1a A top view of the example of the optoelectronic device 1 given in is shown. The optical filter 13 is spaced apart from the contact area 9. Therefore, it is obvious that the optical filter 13 does not cover the contact area 9.

[0062] Figure 2a A cross-sectional view of an exemplary embodiment of the optoelectronic device 1 is shown. The elements corresponding to those of the example according to Figure 1a are denoted by the same reference numerals as the elements according to Figure 2a .

[0063] According to Figure 2a , the optoelectronic device 1 includes a substrate 2 and a photosensitive structure 4 at the main surface 3 of the substrate 2. The substrate 2 can have a main extension plane. As schematically shown, the photosensitive structure 4 can include a photodiode. The optoelectronic device 1 can also include a plurality of photosensitive structures 4 (e.g., arranged in an array). In the array, each photosensitive structure 4 can be arranged in a manner similar to that shown in Figure 2a . The photosensitive structures 4 in the array can be arranged adjacent to each other in a transverse plane or in a plane perpendicular to the transverse plane.

[0064] A dielectric layer 5 is arranged above the substrate 2, at the main surface 3 of the substrate. The dielectric layer 5 has a top surface 6 facing away from the substrate 2.

[0065] At least one wiring layer 7 is arranged in the dielectric layer 5. In the embodiment shown in Figure 2a , two additional wiring layers 8 are arranged in the dielectric layer 5. The wiring layer 7 and the additional wiring layers 8 can be connected to each other. The wiring layer 7 and the additional wiring layers 8 can also connect functional parts in the substrate 2, such as the gates of an IC. The IC is not shown in Figure 2a . In the vertical direction z, the wiring layer 7 and the additional wiring layers 8 are removed above the photosensitive structure 4, where the vertical direction z extends perpendicular to the main extension plane of the substrate 2. This means that in the region above the photosensitive structure 4, the dielectric layer 5 does not have the wiring layer 7 and the additional wiring layers 8.

[0066] At least one contact region 9 is formed by a part of the wiring layer 7. On the side facing away from the substrate 2, the contact region 9 has no dielectric layer 5. The contact region 9 can have a fixed potential, such as ground potential. The fixed potential can be provided by another contact region that is electrically connected to the contact region 9. Figure 2a The other contact region is not shown.

[0067] The passivation layer 10 is arranged in the dielectric layer 5, above the wiring layer 7 and another wiring layer 8. This means that in the vertical direction z, the wiring layer 7 and another wiring layer 8 are arranged between the passivation layer 10 and the substrate 2. A part of the passivation layer 10 is removed above the photosensitive structure 4. This means that in the region above the photosensitive structure 4, the dielectric layer 5 has no passivation layer 10. In the region above the contact region 9, the passivation layer 10 is also removed.

[0068] An opening 11 is formed at the top surface 6 of the dielectric layer 5, which penetrates the dielectric layer 5 and the passivation layer 10 and extends towards the contact region 9. This means that in the vertical direction z, the region on the side facing away from the substrate 2 above the contact region 9 has no dielectric layer 5 and passivation layer 10. The depth of the opening 11 from the top surface 6 of the dielectric layer 5 to the contact region 9 can be at least 0.3 micrometers and at most 10 micrometers. Alternatively, the depth of the opening 11 from the top surface 6 of the dielectric layer 5 to the contact region 9 can be at least 0.5 micrometers and at most 3 micrometers.

[0069] The optical element 12 is arranged above the photosensitive structure 4, on the top surface 6 of the dielectric layer 5. In Figure 2a the illustrated embodiment, the optical element 12 includes an interference filter 12. The interference filter 12 includes a stack of alternating layers, such as a stack of alternating oxide layers and metal layers.

[0070] The optical filter 13 is arranged on the top surface 6 of the dielectric layer 5. The optical filter 13 covers the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. Therefore, the optical filter 13 is in direct contact with the contact region 9. Therefore, the optical filter 13 is also in electrical contact with the contact region 9. The optical filter 13 also covers some positions on the top surface 6 of the dielectric layer 5 and covers a part of the optical element 12. Above the photosensitive structure 4, on the main part of the optical element 12, the optical filter 13 is removed.

[0071] The removal of the optical filter 13, as well as the passivation layer 10, the wiring layer 7, and another wiring layer 8, forms a hole 17 towards the photosensitive structure 4. This means that in the vertical direction z, the optoelectronic device 1 has no such layers above the photosensitive structure 4. The hole 17 also extends in a plane perpendicular to the cross-sectional plane. The shape of the hole 17 can correspond to the shape of the photosensitive structure 4 (see also Figure 2c ).

[0072] In Figure 2a the illustrated embodiment, the optical filter 13 includes a conductive layer 18 and an antireflection coating 19, a black chromium coating 19, or an organic color coating 19 on top of the conductive layer 18. The conductive layer 18 is provided for conductivity and for absorbing unwanted electromagnetic radiation. The conductive layer 18 can include any material having good electrical, mechanical, and optical properties. The thickness of the conductive layer 18 must be within a range where step coverage from the top surface 6 of the dielectric layer 5 to the contact region 9 is feasible. The antireflection coating 19 or the black chromium coating 19 or the organic color coating 19 is provided for additional absorption of unwanted electromagnetic radiation and for reducing the reflectivity of the surface of the optoelectronic device 1. The total thickness of the optical filter 13, i.e., the conductive layer 18 plus the antireflection coating 19 or the black chromium coating 19 or the organic color coating 19, can be at least 0.2 micrometers and at most 10 micrometers. Alternatively, the total thickness of the optical filter can be at least 0.2 micrometers and at most 5 micrometers.

[0073] Figure 2b A cross-sectional view showing another exemplary embodiment of the optoelectronic device 1 is shown.

[0074] According to Figure 2b the embodiment and according to Figure 2a the embodiment differ in the implementation of the optical filter 13. In this embodiment, the optical filter 13 includes only one conductive layer having suitable optical properties. The optical filter 13 can include a conductive black chromium coating or a conductive organic color coating. In both cases, the thickness of the optical filter 13 must be thick enough to cover the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. Thus, the thickness of the optical filter is the same as the range in the Figure 2a embodiment. Figure 2c A top view showing an embodiment according to Figure 2a and 2b is shown.

[0075] A portion of the wiring layer 7 forms a contact region 9 at the location of the opening 11 in the dielectric layer 5. In this embodiment, the shape of the contact region 9 is rectangular in top view, but it can have any suitable shape, such as a circular shape or a polygonal shape.

[0076] The wiring layer 7 and another wiring layer 8 also form a hole 17 towards the photosensitive structure 4. The shape of the hole 17 in top view corresponds to the shape of the photosensitive structure, which is rectangular in this case. However, the shape of the photosensitive structure can have any suitable shape, such as a circular shape or a polygonal shape. The size of the hole 17 can be smaller than the size of the photosensitive structure 4.

[0077] On the one hand, due to the via holes 17 in the wiring layers 7 and 8, the passivation layer 10, and the optical filter 13, the electromagnetic radiation entering the optoelectronic device 1 can reach the photosensitive structure 4 unobstructed. On the other hand, the wiring layer 7 and the additional wiring layer 8 surrounding the photosensitive structure 4 in the vertical direction z prevent the scattered electromagnetic radiation from reaching the photosensitive structure 4. In this way, the arrangement of the wiring layer 7 and the additional wiring 8 additionally prevents crosstalk between the individual photosensitive structures 4.

[0078] The optical filter 13 covers the contact region 9. Accordingly, the optical filter 13 is in direct contact with the contact region 9 and is electrically connected to the contact region 9.

[0079] Figure 2d A top view of another embodiment is shown, in which the optoelectronic device 1 includes an array of photosensitive structures 4. In this embodiment, the array of photosensitive structures 4 includes three photosensitive structures 4 and extends in the lateral direction y. The array of photosensitive structures 4 can also extend in another lateral direction x perpendicular to the lateral direction y. The array of photosensitive structures 4 can also extend in both the lateral direction y and another lateral direction x to form a two-dimensional array. In each lateral direction, the array of photosensitive structures 4 can include any number of photosensitive structures 4.

[0080] Figure 3a A cross-sectional view of another exemplary embodiment of the optoelectronic device 1 is shown. The elements corresponding to the elements of the embodiment according to Figure 2a are denoted by the same reference numerals as the elements according to Figure 3a of the embodiment.

[0081] According to Figure 3a the embodiment differs from the embodiment according to Figure 2a in that the spacer structure 20 covers the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. Accordingly, the spacer structure 20 is in direct contact with the contact region 9. The spacer structure 20 includes three conductive layers. The first conductive layer 21 closest to the substrate 2 and in direct contact with the contact region 9 may include Al. The second conductive layer 22 disposed between the first conductive layer 21 and the third conductive layer 23 may include Ti. The third conductive layer 23, which is the topmost layer in the vertical direction z, may include ITO. The total thickness of the spacer structure 20 must be thick enough to cover the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. The thickness of the first conductive layer 21 may be from 0.3 micrometers to 10 micrometers. The thickness of the second conductive layer 22 may be from 10 nanometers to 1 micrometer. The thickness of the third conductive layer 23 may be from 10 nanometers to 1 micrometer. Alternatively, the thickness of the first conductive layer 21 may be from 0.5 micrometers to 1.5 micrometers. Alternatively, the thickness of the second conductive layer 22 may be from 20 nanometers to 200 nanometers. Alternatively, the thickness of the third conductive layer 23 may be from 50 nanometers to 200 nanometers.

[0082] The optical filter 13 covers a part of the spacer structure 20. Accordingly, the optical filter 13 is electrically connected to the contact region 9. In an embodiment according to Figure 3a , the optical filter 13 includes a conductive layer 18 and an anti-reflection coating 19 or a black chromium coating 19 or an organic color coating 19. The electrical and optical properties of the material layers for the optical filter 13 are the same as those described above in Figure 2a . However, the total thickness of the optical filter 13 can be reduced because the optical filter 13 does not have to cover the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. The total thickness of the optical filter in the vertical direction z can be at least 50 nanometers and at most 2 micrometers. Alternatively, the total thickness of the optical filter in the vertical direction z can be at least 150 nanometers and at most 800 nanometers.

[0083] In addition, in Figure 3a , the IC 24 is shown within the substrate 2 of the optoelectronic device 1. In an embodiment, the IC 24 is arranged at the main surface 3 of the substrate 2, next to the photosensitive structure 4 in the lateral direction y. The IC 24 can also be arranged below the photosensitive structure 4 in the substrate 2 in the vertical direction z.

[0084] Figure 3b A cross-sectional view of another exemplary embodiment of the optoelectronic device 1 is shown. Elements corresponding to the elements of the embodiment according to Figure 3a are denoted by the same reference numerals as in the embodiment according to Figure 3b .

[0085] According to Figure 3b , the embodiment is different from the embodiment according to Figure 3a in the implementation of the optical filter 13. In this embodiment, the optical filter 13 includes only one conductive layer having suitable optical properties. The optical filter 13 can include a conductive black chromium coating or a conductive organic color coating. Compared with the embodiment according to Figure 2b , the thickness of the optical filter 13 can be reduced because the optical filter 13 does not have to cover the bottom portion 14, the sidewalls 15, and the edges 16 of the opening 11 at the top surface 6 of the dielectric layer 5. The thickness of the optical filter can be at least 0.1 micrometer and at most 5 micrometers. Alternatively, depending on the material used, the thickness of the optical filter 13 can be at least 0.1 micrometer and at most 0.8 micrometer.

[0086] Figure 4 A schematic view of an electronic device 25 including the optoelectronic device 1 is shown. The electronic device 25 can be, for example, a camera system or an electromagnetic radiation sensor. For example, the electronic device 25 can be used in applications in the automotive, industrial, medical, consumer market, and scientific fields.

[0087] This patent application claims the priority of European Patent Application No. 19191268.2, the disclosure of which is incorporated herein by reference.

[0088] List of Reference Numerals

[0089] 1 Photoelectric device

[0090] 2 Substrate

[0091] 3 Main surface of the substrate

[0092] 4 Photosensitive structure

[0093] 5 Dielectric layer

[0094] 6 Top surface of the dielectric layer

[0095] 7 Wiring layer

[0096] 8 Additional wiring layer

[0097] 9 Contact area

[0098] 10 Passivation layer

[0099] 11 Opening

[0100] 12 Optical element

[0101] 13 Optical filter

[0102] 14 Bottom part of the opening

[0103] 15 Sidewall of the opening

[0104] 16 Edge of the opening

[0105] 17 Hole

[0106] 18 Conductive layer of the optical filter

[0107] 19 Anti-reflection coating or black chromium coating or organic color coating

[0108] 20 Spacer structure

[0109] 21 First conductive layer of the spacer structure

[0110] 22 Second conductive layer of the spacer structure

[0111] 23 Third conductive layer of the spacer structure

[0112] 24 Integrated circuit (IC)

[0113] 25 Electronic device

[0114] x, y Lateral directions

[0115] z Vertical direction

Claims

1. An optoelectronic device (1), comprising: - a substrate (2) having a photosensitive structure (4), - a dielectric layer (5) on a main surface (3) of the substrate (2), the dielectric layer (5) having a top surface (6) facing away from the substrate (2), - at least one wiring layer (7) disposed in the dielectric layer (5), - at least one contact region (9) formed by a part of the at least one wiring layer (7), - an opening (11) in the dielectric layer (5) at the top surface (6), the opening (11) extending towards the contact region (9), - an optical element (12) disposed on the top surface (6) of the dielectric layer (5) above the photosensitive structure (4), - an optical filter (13) disposed on the top surface (6) of the dielectric layer (5), the optical filter (13) being conductive, covering a part of the optical element (12) and being in electrical contact with the contact region (9), and - a spacer structure (20) covering a bottom part (14), side walls (15) and an edge (16) of the opening (11) at the top surface (6) of the dielectric layer (5), and electrically connecting the contact region (9) to the optical filter (13).

2. The optoelectronic device (1) according to claim 1, wherein the optical filter (13) covers the bottom part (14), side walls (15) and the edge (16) of the opening (11) at the top surface (6) of the dielectric layer (5), and is in electrical contact with the contact region (9).

3. The optoelectronic device (1) according to claim 1, wherein the spacer structure (20) comprises a stack of at least two conductive layers (21, 22, 23).

4. The optoelectronic device (1) according to any one of claims 1 to 3, wherein the optical filter (13) comprises a conductive layer (18).

5. The optoelectronic device (1) according to any one of claims 1 to 3, wherein the optical filter (13) comprises an anti-reflection coating (19), an organic color coating (19) or a black chromium coating (19).

6. The optoelectronic device (1) according to any one of claims 1 to 3, comprising: a passivation layer (10) disposed above the at least one wiring layer (7) in the dielectric layer (5).

7. The optoelectronic device (1) according to any one of claims 1 to 3, comprising: an integrated circuit (24) in the substrate (2).

8. The optoelectronic device (1) according to any one of claims 1 to 3, wherein the optical element (12) is an interference filter.

9. The optoelectronic device (1) according to any one of claims 1 to 3, wherein the photosensitive structure (4) is a single photodiode or an array of photodiodes.

10. An electronic device (25) comprising the optoelectronic device (1) according to any one of claims 1 to 9.

11. The electronic device (25) according to claim 10, wherein the electronic device (25) is a camera system or an electromagnetic radiation sensor.

12. A method of manufacturing an optoelectronic device (1), comprising: - providing a substrate (2) and forming a photosensitive structure (4) in the substrate (2), - depositing a dielectric layer (5) on the substrate (2), the dielectric layer (5) having a top surface (6) facing away from the substrate (2), - depositing at least one wiring layer (7), the at least one wiring layer (7) being arranged within the dielectric layer (5), and a contact region (9) being formed by a portion of the at least one wiring layer (7), - forming an opening (11) at the top surface (6) of the dielectric layer (5), the opening (11) extending towards the contact region (9), - depositing an optical element (12) on the dielectric layer (5), the optical element (12) being arranged above the photosensitive structure (4) in the substrate (2), - depositing an optical filter (13) on the top surface (6) of the dielectric layer (5), the optical filter (13) being conductive, covering a portion of the optical element (12) and being in electrical contact with the contact region (9), and - before depositing the optical filter (13), depositing a spacer structure (20) into the opening (11) of the dielectric layer (5) and depositing on the contact region (9), the spacer structure (20) covering the bottom portion (14), sidewalls (15) and edges (16) of the opening (11) at the top surface (6) of the dielectric layer (5).

13. The method according to claim 12, wherein the optical filter (13) is arranged on the top surface (6) of the dielectric layer (5), on a portion of the optical element (12) and in the opening (11) of the dielectric layer (5), the optical filter (13) covering the bottom portion (14), sidewalls (15) and edges (16) of the opening (11) at the top surface (6) of the dielectric layer (5).

14. The method according to claim 12, wherein the optical filter (13) is arranged on the top surface (6) of the dielectric layer (5), on a portion of the optical element (12) and on a portion of the spacer structure (20).

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