Optical device

Abstract

An optical device. The optical device comprises a first insulating layer and a first waveguide, the first insulating layer is located above the substrate, and the first waveguide is located in the first insulating layer. The first waveguide includes a first main portion and a first curved portion extending upwardly from the first main portion and away from the substrate. The optical device also includes a second waveguide over the first waveguide, the second waveguide including a second main portion over the first insulating layer and a second curved portion extending downwardly from the second main portion and into the first insulating layer.

Description

Technical Field

[0001] This utility model relates to an optical device and its manufacturing method, and more particularly to an optical device comprising a first waveguide and a second waveguide and its manufacturing method. Background Technology

[0002] Optical signal processing is a technology for signal transmission and processing. In recent years, especially due to the application of fiber optic correlation in signal transmission, optical signal processing has been used in an increasing number of applications.

[0003] Optical signal processing is often combined with electrical signal processing to provide a comprehensive range of applications. For example, optical fibers can be used for long-distance signal transmission, while electrical signals can be used for short-distance signal transmission, processing, and control. Therefore, devices integrating long-distance optical components and short-distance electronic components are formed for the conversion between optical and electrical signals, as well as the processing of both. The package can thus contain both an optical (electronic) chip (which contains the optical components) and an electronic chip (which contains the electronic components). Utility Model Content

[0004] The purpose of this invention is to provide an optical device to solve at least one of the above-mentioned problems.

[0005] One embodiment of this utility model is a method for manufacturing an optical device. The method for manufacturing an optical device includes forming a first waveguide in a first insulating layer above a substrate, wherein the first waveguide includes a first main portion and a first curved portion, the first curved portion extending upward from the first main portion and away from the substrate; and forming a second waveguide above the first waveguide, wherein the second waveguide includes a second main portion and a second curved portion, the second main portion being located above the first insulating layer, and the second curved portion extending downward from the second main portion and into the first insulating layer.

[0006] Another embodiment of this utility model is a method for manufacturing an optical device. The method includes forming a first waveguide above a substrate; forming a first insulating layer covering the first waveguide and located above the substrate; forming a first groove in the first insulating layer to expose a first end of the first waveguide; performing a first injection process on the first end of the first waveguide to form a first curved portion of the first waveguide, wherein the first curved portion bends upward relative to a portion of the first waveguide not exposed by the first groove; forming a second waveguide above the first insulating layer, wherein there is a horizontal gap between the second waveguide and the first curved portion of the first waveguide; forming a second insulating layer covering the second waveguide and located above the first insulating layer; forming a second groove in the second insulating layer and the first insulating layer to expose a second end of the second waveguide, the second end of the second waveguide being adjacent to the first curved portion of the first waveguide; and performing a second injection process on the second end of the second waveguide to form a second curved portion of the second waveguide, wherein the second curved portion bends downward relative to a portion of the second waveguide not exposed by the second groove.

[0007] Another embodiment of this utility model is an optical device. The optical device includes a first insulating layer located above a substrate; a first waveguide located in the first insulating layer, wherein the first waveguide includes a first main portion and a first curved portion, the first curved portion extending upward from the first main portion and away from the substrate; and a second waveguide located above the first waveguide, wherein the second waveguide includes a second main portion and a second curved portion, the second main portion being located above the first insulating layer, and the second curved portion extending downward from the second main portion and into the first insulating layer.

[0008] According to one embodiment of the present invention, the first curved portion of the first waveguide overlaps with the second curved portion of the second waveguide in the vertical direction.

[0009] According to one embodiment of the present invention, the first main portion of the first waveguide is parallel to the second main portion of the second waveguide.

[0010] According to one embodiment of the present invention, the second curved portion and the first curved portion form a coupler.

[0011] According to one embodiment of the present invention, the first curved portion extends vertically above half the thickness between the upper surface of the first insulating layer and the upper surface of the first main portion.

[0012] According to one embodiment of the present invention, the optical device further includes: a second insulating layer located above the first insulating layer, wherein the second main portion is located in the second insulating layer.

[0013] According to one embodiment of the present invention, the second waveguide further includes a third curved portion that extends upward from the second main portion.

[0014] According to one embodiment of the present invention, the third curved portion extends vertically above half the thickness between the upper surface of the second insulating layer and the upper surface of the second main portion.

[0015] According to one embodiment of the present invention, the optical device further includes: a third waveguide located above the second waveguide, wherein the third waveguide includes a third main portion and a fourth curved portion, the third main portion being located above the second insulating layer, and the fourth curved portion extending downward from the third main portion and into the second insulating layer.

[0016] According to one embodiment of the present invention, the third curved portion and the fourth curved portion form a coupler. Attached Figure Description

[0017] The complete disclosure is based on the following detailed description and the accompanying drawings. It should be noted that, in accordance with the general practice of the industry, the illustrations are not necessarily drawn to scale. In fact, the dimensions of components may be arbitrarily enlarged or reduced for clarity.

[0018] Figures 1 to 9 This is a cross-sectional view illustrating an intermediate stage in the fabrication of an optical interconnect structure, according to some embodiments.

[0019] Figures 10 to 14 This is a cross-sectional view illustrating an intermediate stage in the fabrication of an optical interconnect structure, according to some embodiments.

[0020] Figures 15 to 21 This is a cross-sectional view illustrating an intermediate stage in the fabrication of an optical interconnect structure, according to some embodiments.

[0021] Figure 22 This is a cross-sectional view of an intermediate stage of an optical interconnect structure according to some embodiments.

[0022] Figures 23 to 25 This is a cross-sectional view of an intermediate stage of a photonic integrated circuit, based on some embodiments.

[0023] The attached figures are labeled as follows:

[0024] 100, 200, 300, 400: Optical interconnect structure

[0025] 101:Substrate

[0026] 103,509: First insulating layer

[0027] 105: First Waveguide

[0028] 105a, 105d: End

[0029] 105a', 105d': Curved portion

[0030] 105b, 105e: Main parts

[0031] 113,519: Second insulating layer

[0032] 117,137,237,337,357: Groove

[0033] 119,139,239,339,359: Mask layer

[0034] 121,141,241,341: Injection process

[0035] 125, 325: Second waveguide

[0036] 125a, 125c: End caps

[0037] 125a', 125c': Bending section

[0038] 125b: Main part

[0039] 133,333,539: Third insulating layer

[0040] 180, 280, 380: Couplers

[0041] 245, 345: Third waveguide

[0042] 245a': Bending section

[0043] 245b, 345e: Main parts

[0044] 253,353: Fourth insulating layer

[0045] 345d: End

[0046] 345d': Bending section

[0047] 500: Photonic Integrated Circuits

[0048] 501:Substrate

[0049] 502: Intermediate Insulation Layer

[0050] 505: Active layer

[0051] 507: Optical Components

[0052] 517: First metallized component

[0053] 537: Second metallized component

[0054] D: Distance

[0055] G1, G2: Gap

[0056] L1, L2, L3, L4, L5: Length

[0057] T1, T2, T3: Thickness

[0058] W1, W2, W3, W4, W5: Width Detailed Implementation

[0059] The following disclosure provides many different embodiments or examples to implement various features of this utility model. The following disclosure describes specific examples of the various components and their arrangements for simplification. Of course, these specific examples are not intended to be limiting. For example, if this disclosure describes a first feature formed on or above a second feature, it means that it may include embodiments where the first and second features are in direct contact, or embodiments where an additional feature is formed between the first and second features, so that the first and second features may not be in direct contact. Furthermore, the same reference numerals and / or designations may be used repeatedly in different examples of the following disclosure. These repetitions are for simplification and clarity and are not intended to limit any specific relationship between the different embodiments and / or structures discussed.

[0060] Furthermore, spatially related terms, such as "below," "below," "lower," "above," "higher," and similar terms, are used to facilitate the description of the relationship between one element or feature and another(s) in the illustration. In addition to the orientations shown in the accompanying drawings, these spatially related terms are intended to encompass different orientations of the device in use or operation. The device may be rotated to different orientations (90 degrees or other orientations), and the spatially related terms used herein can be interpreted in the same way.

[0061] The embodiments will be described with respect to optical interconnect structures comprising specific embodiments of multilayer optical waveguides. In some embodiments of the present invention, the optical waveguides have one or more curved portions that may extend upward or downward from the main portion of the optical waveguide. Thus, the optical waveguides can be interconnected by bringing the curved portions of different layers of optical waveguides close to each other. Vertical optical interconnects can thus be provided. However, the embodiments presented herein are intended to illustrate the proposed ideas and are not intended to be limiting.

[0062] Figures 1 to 9 This is a cross-sectional view illustrating an intermediate stage in the fabrication of the optical interconnect structure 100 according to some embodiments. (Refer to...) Figure 1This diagram illustrates an initial structure having a substrate 101 and a first insulating layer 103 formed above the substrate 101, which is a first step in forming the optical interconnect structure 100. Focusing first on the substrate 101, the substrate 101 may comprise an active layer of bulk silicon (doped or undoped) or a silicon-on-insulator (SOI) substrate. Generally, SOI substrates comprise a semiconductor material layer, such as silicon, germanium, silicon-germanium, SOI, silicon-germanium-on-insulator (SGOI), or combinations thereof. Other usable substrates include multilayer substrates, gradient substrates, or hybrid orientation substrates. Furthermore, the substrate 101 at this point may be part of a semiconductor wafer. Figure 1 (The complete wafer is not shown in the image). The wafer will be diced separately in subsequent steps.

[0063] In one embodiment, the first insulating layer 103 may be a cladding material and / or a dielectric layer, such as silicon dioxide, silicon nitride, germanium oxide, germanium nitride, combinations thereof, or the like, formed using processes such as thermal oxidation, plasma-assisted chemical vapor deposition, other chemical vapor deposition processes, physical vapor deposition, combinations thereof, or similar processes. However, any suitable materials and manufacturing methods may be used.

[0064] Reference Figure 2 Once the first insulating layer 103 is formed, a first waveguide 105 can be formed on top of the first insulating layer 103. In one embodiment, the first waveguide 105 can be any suitable type of waveguide (e.g., ridge waveguide, rib waveguide, buried channel waveguide, diffused waveguide, etc.), and a core material, such as silicon nitride, amorphous silicon (a-Si), aluminum nitride (AlN), aluminum oxide (Al2O3), tantalum pentoxide (Ta2O5), or a combination thereof, with a thickness T1 of approximately 0.1 micrometers (μm) to 1 micrometer can be deposited first using methods such as chemical vapor deposition, physical vapor deposition, atomic layer deposition, combinations thereof, or similar methods. Once the core material is deposited on top of the first insulating layer 103, the core material can be patterned into the designed shape of the first waveguide 105 using processes such as photolithographic masking and etching. However, any suitable material, thickness, and manufacturing method can be used. The first waveguide 105 may include a narrowed width of about 1 nanometer (nm) to about 200 nanometers. In some embodiments, the first waveguide 105 may include a width that gradually narrows toward one end of the first waveguide 105 in a top view.

[0065] After the first waveguide 105 is formed, a second insulating layer 113 is formed on top of the first waveguide 105. In one embodiment, the second insulating layer 113 can be formed using a material and formation method similar to that used for the first insulating layer 103, such as depositing a material like silicon dioxide using a deposition method like low-temperature plasma-assisted chemical vapor deposition. However, any suitable material and manufacturing method can be used. In some embodiments, the thickness T2 of the second insulating layer 113 is from about 1 micrometer to about 30 micrometers. The thickness T3 between the upper surface of the first waveguide 105 and the upper surface of the second insulating layer 113 is from about 0.9 micrometers to about 29.9 micrometers.

[0066] Reference Figure 3 After the second insulating layer 113 is formed, a groove 117 is formed to expose the end 105a of the first waveguide 105. The main portion 105b of the first waveguide 105 remains covered by the second insulating layer 113. In some embodiments, the end 105a of the first waveguide 105 has a length L1. The length L1 may be greater than half the thickness T2 of the second insulating layer 113, or may be greater than or equal to the thickness T2 of the second insulating layer 113. For example, the length L1 may be from about 1 micrometer to about 30 micrometers. The width W1 of the groove 117 may be greater than the length L1 and extend to a depth deeper than the bottom of the first waveguide 105 to allow the end 105a of the first waveguide 105 to move freely in subsequent processes. Because the material of the first waveguide 105 (e.g., silicon nitride or other materials described above) is rigid, the end 105a of the first waveguide 105 can be suspended in the groove 117.

[0067] In some embodiments, the groove 117 can be formed by etching the second insulating layer 113 and the first insulating layer 103 according to a pattern of the mask layer 119. For example, the formation of the mask layer 119 may include depositing a mask material over the second insulating layer 113 by any suitable deposition process and patterning the mask material by any suitable patterning process to form a pattern in the mask layer 119. The mask layer 119 may be a hard mask, such as titanium nitride, silicon nitride, silicon oxynitride, silicon carbide, other suitable materials, or combinations thereof. Alternatively, the mask layer 119 may be a photoresist material. The etching process for forming the groove 117 may include a wet etching process or a combination of a dry etching process followed by a wet etching process, using an etchant containing fluorine (e.g., HF, CF3, C2F2, etc.). The etching process may be highly selective for the second insulating layer 113 and the first insulating layer 103 relative to the first waveguide 105.

[0068] Reference Figure 4After the end portion 105a of the first waveguide 105 is exposed in the groove 117, an implantation process 121 is performed on the end portion 105a of the first waveguide 105 according to some embodiments. During the implantation process 121, other portions of the first waveguide 105 (such as the main portion 105b) are masked by a mask layer 119. The implantation process 121 may include injecting a first implant into the end portion 105a of the first waveguide 105. The first implant may contain nitrogen ions (N... + ), silicon ions (Si + Other suitable ions or combinations thereof. The first implanted substance can be delivered using an ion beam, with a dose starting from approximately 1 × 10⁻⁶. 14 atoms per square centimeter (atoms / cm) 2 ) to approximately 1×10 16 Atoms per square centimeter, implantation energy from approximately 100 keV to approximately 150 keV, temperature from approximately -30 degrees Celsius to approximately 200 degrees Celsius. Annealing is not required after implantation process 121.

[0069] In some embodiments, the depth of the peak concentration of the first injector in the end portion 105a of the first waveguide 105 can be well controlled by the injection process 121. For example, the peak concentration of the first injector is located in the lower half of the end portion 105a of the first waveguide 105, or in the bottom third of the end portion 105a of the first waveguide 105. Alternatively, the concentration of the first injector in the lower half of the end portion 105a of the first waveguide 105 is greater than the concentration in the upper half of the end portion 105a of the first waveguide 105. Therefore, compressive stress is generated in the upper half of the end portion 105a of the first waveguide 105. The end portion 105a of the first waveguide 105 bends upward from the main portion 105b to form a bent portion 105a'. In some embodiments, the bent portion 105a' may have a bent shape. The bent portion 105a' of the first waveguide 105 may extend vertically above half the thickness T3 between the upper surface of the second insulating layer 113 and the upper surface of the main portion 105b of the first waveguide 105. The mask layer 119 used to form the groove 117 can be removed by any suitable method after the injection process 121, such as by an etching process.

[0070] Reference Figure 5After forming the curved portion 105a' of the first waveguide 105, a deposition process is performed, according to some embodiments, to fill the recess 117. The deposition process may provide the same material as the second insulating layer 113 and the first insulating layer 103. Thus, the supplemented second insulating layer 113 can encapsulate the curved portion 105a' of the first waveguide 105. The deposition process may include plasma-assisted chemical vapor deposition, other chemical vapor deposition processes, physical vapor deposition, combinations thereof, or similar deposition methods. In some embodiments, if the mask layer 119 is not removed immediately after the injection process 121, the mask layer 119 is removed after the deposition process filling the recess 117. Following subsequent deposition, planarization processes such as chemical mechanical polishing (CMP) or mechanical grinding may be selectively performed to remove excess material above the second insulating layer 113.

[0071] Reference Figure 6 A second waveguide 125 may be formed over the second insulating layer 113. In one embodiment, the second waveguide 125 may be formed using materials and manufacturing methods similar to those used for the first waveguide 105, such as depositing a material like silicon nitride using a chemical vapor deposition process. However, any suitable materials and manufacturing methods may be used. In some embodiments, the second waveguide 125 has one end adjacent to a bend 105a' of the first waveguide 105. The second waveguide 125 may have a horizontal gap (greater than 0) between it and the bend 105a' of the first waveguide 105. In some embodiments, the second waveguide 125 includes a narrowed width between about 1 nanometer and about 200 nanometers. For example, the second waveguide 125 includes a width that gradually narrows toward one end adjacent to the first waveguide 105 and / or the other ends of the second waveguide 125.

[0072] After the second waveguide 125 is formed, a third insulating layer 133 may be formed over the second waveguide 125 and the second insulating layer 113. In one embodiment, the third insulating layer 133 may be formed using a material and formation method similar to that of the first insulating layer 103 described above, such as depositing a material like silicon dioxide using a deposition method such as low-temperature plasma-assisted chemical vapor deposition. However, any suitable material and manufacturing method may be used.

[0073] Reference Figure 7After the third insulating layer 133 is formed, a groove 137 is formed to expose the end portion 125a of the second waveguide 125. The main portion 125b of the second waveguide 125 remains covered by the third insulating layer 133. In some embodiments, the end portion 125a of the second waveguide 125 has a length L2. The length L2 may be greater than half the thickness of the third insulating layer 133, or greater than or equal to the thickness of the third insulating layer 133. For example, the length L2 may be from about 1 micrometer to about 30 micrometers. In some embodiments, the length L2 is the same as the length L1. Alternatively, the length L2 may be different from the length L1. The width W2 of the groove 137 may be greater than the length L2 and extend to a depth deeper than the bottom of the second waveguide 125 to allow the end portion 125a of the second waveguide 125 to move freely in subsequent processes. In some embodiments, the depth of the groove 137, measured from the upper surface of the second insulating layer 113, is greater than the length L2. The end portion 125a of the second waveguide 125 may be suspended in the groove 137.

[0074] In some embodiments, the groove 137 can be formed by etching the third insulating layer 133 and the second insulating layer 113 according to the pattern of the mask layer 139. In one embodiment, the mask layer 139 can be formed using a material and formation method similar to that of the mask layer 119 described above. However, any suitable material and manufacturing method can be used. The etching process for forming the groove 137 may include a wet etching process or a combination of a dry etching process followed by a wet etching process, using an etchant containing fluorine (e.g., HF, CF3, C2F2, etc.). The etching process can be highly selective for the third insulating layer 133 and the second insulating layer 113 relative to the second waveguide 125.

[0075] Reference Figure 8 After the end portion 125a of the second waveguide 125 is exposed in the groove 137, according to some embodiments, an implantation process 141 is performed on the end portion 125a of the second waveguide 125. During the implantation process 141, other portions of the first waveguide 105 and the second waveguide 125 may be masked by the mask layer 139. The implantation process 141 may include implanting a second implant into the end portion 125a of the second waveguide 125. The second implant may contain nitrogen ions (N... + ), silicon ions (Si + Other suitable ion implants or combinations thereof. The second implant can be delivered using an ion beam, with doses starting from approximately 1 × 10⁻⁶. 14 From atoms per square centimeter to approximately 1 × 10 16 Atoms per square centimeter, implantation energy from approximately 10 keV to approximately 50 keV, and temperature from approximately -30 degrees Celsius to approximately 200 degrees Celsius. Annealing is not required after implantation process 141.

[0076] The depth of the peak concentration of the second injector in the end portion 125a of the second waveguide 125 can be well controlled by the injection process 141. For example, the peak concentration of the second injector is located in the upper half of the end portion 125a of the second waveguide 125, or in the top third of the end portion 125a of the second waveguide 125. Alternatively, the concentration of the second injector in the upper half of the end portion 125a of the second waveguide 125 is greater than the concentration in the lower half of the end portion 125a of the second waveguide 125. Therefore, compressive stress is generated in the lower half of the second waveguide 125. The end portion 125a of the second waveguide 125 bends downward from the main portion 125b to form a bent portion 125a'. In some embodiments, the bent portion 125a' may have a bent shape. The bent portion 125a' of the second waveguide 125 may extend vertically below half the thickness between the bottom surface of the main portion 125b of the second waveguide 125 and the top surface of the main portion 105b of the first waveguide 105. The mask layer 139 used to form the groove 137 can be removed by any suitable method after the injection process 141, such as by an etching process.

[0077] Reference Figure 9 After forming the curved portion 125a' of the second waveguide 125, a deposition process is performed, according to some embodiments, to fill the recess 137. The deposition process may provide the same material as the third insulating layer 133 and the second insulating layer 113. Thus, the supplemented third insulating layer 133 can encapsulate the curved portion 125a' of the second waveguide 125. The deposition process may include plasma-assisted chemical vapor deposition, other chemical vapor deposition processes, physical vapor deposition, combinations thereof, or similar deposition methods. In some embodiments, if the mask layer 139 is not removed immediately after the implantation process 141, the mask layer 139 is removed after the deposition process filling the recess 137. Following subsequent deposition, planarization processes such as chemical mechanical polishing (CMP) or mechanical grinding may be selectively performed to remove excess material above the third insulating layer 133.

[0078] Because the curved portion 105a' of the first waveguide 105 bends upward and the curved portion 125a' of the second waveguide 125 bends downward, the curved portions 105a' of the first waveguide 105 and 125a' of the second waveguide 125 can be close to each other or even overlap in the vertical direction. For example, the distance D between the curved portions 125a' of the second waveguide 125 and 105a' of the first waveguide 105 can be less than about 1 micrometer. Therefore, the curved portions 105a' of the first waveguide 105 and 125a' of the second waveguide 125 can form a coupler 180. The coupler 180 can be an inter-layer coupler, providing vertical interconnection for waveguides in different layers (e.g., in different insulating layers). For example, the first waveguide 105 and the second waveguide 125 can transmit optical signals to each other through the coupler 180. By forming the curved portions of the waveguides, the optical interconnect structure 100 can provide vertical optical interconnection. The main part of the waveguide can still provide horizontal optical interconnects, thus providing a highly integrated optical interconnect structure 100.

[0079] Figures 10 to 14 This is a cross-sectional view illustrating an intermediate stage in the fabrication of an optical interconnect structure 200 according to some embodiments. The optical interconnect structure 200 can be formed using similar process steps to the optical interconnect structure 100, wherein similar element symbols represent similar feature components. In particular, Figure 10 The process shown is assumed to have been performed previously. Figures 1 to 9 The process is illustrated. In some embodiments, the waveguide in the optical interconnect structure 200 includes multiple bends that allow the waveguide to form couplers with waveguides in lower layers, higher layers, or both.

[0080] Reference Figure 10 A groove 237 may be formed to expose the other end of the second waveguide 125, such as end 125c of the second waveguide 125. In some embodiments, end 125c of the second waveguide 125 may have a length L3. The length L3 may be greater than half the thickness of the third insulating layer 133, or greater than or equal to the thickness of the third insulating layer 133. For example, the length L3 may be from about 1 micrometer to about 30 micrometers. The width W3 of the groove 237 may be greater than the length L3 and extend to a depth deeper than the bottom of the second waveguide 125 to allow end 125c of the second waveguide 125 to move freely in subsequent processes. End 125c of the second waveguide 125 may be suspended in the groove 237.

[0081] In some embodiments, the groove 237 can be formed by etching the third insulating layer 133 and the second insulating layer 113 according to the pattern of the mask layer 239. In one embodiment, the mask layer 239 can be formed using a material and forming method similar to that of the mask layer 119 described above. However, any suitable material and manufacturing method can be used. The etching process for forming the groove 237 can include a wet etching process or a combination of a dry etching process followed by a wet etching process, using an etchant containing fluorine (e.g., HF, CF3, C2F2, etc.). The etching process can be highly selective for the third insulating layer 133 and the second insulating layer 113 relative to the second waveguide 125.

[0082] Reference Figure 11 After the end portion 125c of the second waveguide 125 is exposed in the groove 237, according to some embodiments, an implantation process 241 is performed on the end portion 125c of the second waveguide 125. The implantation process 241 may include implanting a third implant into the end portion 125c of the second waveguide 125. The third implant may contain nitrogen ions (N... + ), silicon ions (Si + ), other suitable ion implants or combinations thereof. A third implant can be delivered using an ion beam, with doses starting from approximately 1 × 10⁻⁶. 14 From atoms per square centimeter to approximately 1 × 10 16 Atoms per square centimeter, implantation energy from approximately 100 keV to approximately 150 keV, temperature from approximately -30 degrees Celsius to approximately 200 degrees Celsius. Annealing is not required after implantation process 241.

[0083] The depth of the peak concentration of the third injected material in the end portion 125c of the second waveguide 125 can be well controlled by the injection process 241. For example, the peak concentration of the third injected material is located in the lower half of the end portion 125c of the second waveguide 125, or in the bottom third of the end portion 125c. Alternatively, the concentration of the third injected material in the lower half of the end portion 125c of the second waveguide 125 is greater than the concentration in the upper half of the end portion 125c of the second waveguide 125. Therefore, compressive stress is generated in the upper half of the end portion 125c of the second waveguide 125. The end portion 125c of the second waveguide 125 bends upward from the main portion 125b to form a bent portion 125c'. In some embodiments, the bent portion 125c' may have a bent shape. The bent portion 125c' of the second waveguide 125 may extend vertically above half the thickness between the upper surface of the third insulating layer 133 and the upper surface of the main portion 125b of the second waveguide 125. The mask layer 239 used to form the groove 237 can be removed by any suitable method after the injection process 241, such as by an etching process.

[0084] Reference Figure 12After forming the curved portion 125c' of the second waveguide 125, a deposition process is performed, according to some embodiments, to fill the recess 237. The deposition process may provide the same material as the third insulating layer 133. Thus, the supplemented third insulating layer 133 can encapsulate the curved portion 125c' of the second waveguide 125. For example, the deposition process may include plasma-assisted chemical vapor deposition, other chemical vapor deposition processes, physical vapor deposition, combinations thereof, or similar deposition methods. In some embodiments, if the mask layer 239 is not removed immediately after the implantation process 241, the mask layer 239 is removed after the deposition process filling the recess 237. Following subsequent deposition, a planarization process, such as CMP or mechanical polishing, may be selectively performed to remove excess material above the third insulating layer 133.

[0085] Reference Figure 13 A third waveguide 245 may be formed above the third insulating layer 133. In one embodiment, the third waveguide 245 may be formed using materials and manufacturing methods similar to those used for the first waveguide 105 described above, such as depositing a material like silicon nitride using a chemical vapor deposition process. However, any suitable materials and manufacturing methods may be used. In some embodiments, the third waveguide 245 may have one end adjacent to a bend 125c' of the second waveguide 125. In some embodiments, there is a horizontal gap (greater than 0) between the third waveguide 245 and the bend 125c' of the second waveguide 125. In some embodiments, the third waveguide 245 includes a narrowed width between about 1 nanometer and about 200 nanometers. For example, the third waveguide 245 includes a width that gradually narrows toward one end adjacent to the second waveguide 125.

[0086] After the third waveguide 245 is formed, a fourth insulating layer 253 may be formed on top of the third waveguide 245. In one embodiment, the fourth insulating layer 253 may be formed using a material and formation method similar to the first insulating layer 103 described above, such as depositing a material like silicon dioxide using a deposition method such as low-temperature plasma-assisted chemical vapor deposition. However, any suitable material and manufacturing method may be used.

[0087] Reference Figure 14 According to some embodiments, the operation is similar to that described above. Figures 7 to 9The manufacturing steps described herein. For example, an injection process is performed on one end of the third waveguide 245 to form a bent portion 245a'. The bent portion 245a' may extend downward from the main portion 245b of the third waveguide 245. Since the bent portion 125c' of the second waveguide 125 bends upward and the bent portion 245a' of the third waveguide 245 bends downward, the bent portions 125c' of the second waveguide 125 and 245a' of the third waveguide 245 may be close to each other or even overlap in the vertical direction. For example, the distance between the bent portions 125c' of the second waveguide 125 and 245a' of the third waveguide 245 is less than or equal to a distance D. Therefore, the bent portions 125c' of the second waveguide 125 and 245a' of the third waveguide 245 may form a coupler 280. The coupler 280 may be an interlayer coupler providing vertical interconnection for waveguides in different layers (e.g., in different insulating layers). For example, the third waveguide 245 and the second waveguide 125 can transmit optical signals to each other via coupler 280. The third waveguide 245 can further communicate with the first waveguide 105 via the second waveguide 125 and couplers 180 and 280. Furthermore, not only can the second waveguide have multiple curved sections, but other waveguides in any layer can also have multiple curved sections bending upwards or downwards. Thus, any number of couplers can be formed in the optical interconnect structure 200, providing a highly integrated optical interconnect structure 200.

[0088] Figures 15 to 21 This is a cross-sectional view illustrating an intermediate stage in the fabrication of an optical interconnect structure 300 according to some embodiments. The optical interconnect structure 300 can be formed using similar process steps to the optical interconnect structure 100, wherein similar element symbols represent similar feature components. In particular, Figure 15 The process shown is assumed to have been performed previously. Figures 1 to 2 The process is illustrated. In some embodiments, the optical interconnect structure 300 provides a coupler spanning more than one insulating layer.

[0089] Reference Figure 15 In one embodiment, a second waveguide 325 may be formed above the second insulating layer 113. The second waveguide 325 may be formed using materials and manufacturing methods similar to those used for the first waveguide 105, such as depositing a material like silicon nitride using a chemical vapor deposition process. However, any suitable materials and manufacturing methods may be used. A horizontal gap G1 exists between the second waveguide 325 and the first waveguide 105. In some embodiments, the gap G1 is greater than the length L1 and distance D described above. For example, the gap G1 may be from about 2 micrometers to about 100 micrometers.

[0090] After the second waveguide 325 is formed, a third insulating layer 333 may be formed on top of the second waveguide 325. In one embodiment, the third insulating layer 333 may be formed using a material and formation method similar to the first insulating layer 103 described above, such as depositing a material like silicon dioxide using a deposition method such as low-temperature plasma-assisted chemical vapor deposition. However, any suitable material and manufacturing method may be used.

[0091] Reference Figure 16 After forming the second waveguide 325 and the third insulating layer 333, a groove 337 is formed to expose the end 105d of the first waveguide 105. The main portion 105e of the first waveguide 105 remains covered by the second insulating layer 113. In some embodiments, the end 105d of the first waveguide 105 has a length L4. The length L4 may be greater than the thickness T2 of the second insulating layer 113, or greater than or equal to twice the thickness T2 of the second insulating layer 113. For example, the length L4 may be from about 1 micrometer to about 30 micrometers. The width W4 of the groove 337 may be greater than the length L4 and extend to a depth deeper than the bottom of the first waveguide 105 to allow the end 105d of the first waveguide 105 to move freely in subsequent processes. The end 105d of the first waveguide 105 may be suspended in the groove 337.

[0092] In some embodiments, the groove 337 can be formed by etching the third insulating layer 333, the second insulating layer 113, and the first insulating layer 103 according to a pattern of the mask layer 339. For example, forming the mask layer 339 may include depositing a mask material over the third insulating layer 333 by any suitable deposition process and patterning the mask material by any suitable patterning process to form a pattern in the mask layer 339. The mask layer 339 may be a hard mask, such as titanium nitride, silicon nitride, silicon oxynitride, silicon carbide, other suitable materials, or combinations thereof. Alternatively, the mask layer 339 may be a photoresist material. The etching process for forming the groove 337 may include a wet etching process or a combination of a dry etching process followed by a wet etching process, using an etchant containing fluorine (e.g., HF, CF3, C2F2, etc.). The etching process may be highly selective for the second insulating layer 113 and the first insulating layer 103 relative to the first waveguide 105.

[0093] Reference Figure 17 After forming the groove 337, an implantation process 341 is performed on the end 105d of the first waveguide 105. During the implantation process 341, other portions of the first waveguide 105 and the second waveguide 325 are shielded by a mask layer 339. The implantation process 341 may include injecting a fifth implant into the end 105d of the first waveguide 105. The fifth implant may contain nitrogen ions (N... + ), silicon ions (Si +Other suitable ion implants or combinations thereof. The fifth implant can be delivered using an ion beam, with doses starting from approximately 1 × 10⁻⁶. 14 From atoms per square centimeter to approximately 1 × 10 16 Atoms per square centimeter, implantation energy from approximately 100 keV to approximately 150 keV, temperature from approximately -30 degrees Celsius to approximately 200 degrees Celsius. Annealing is not required after implantation process 341.

[0094] The depth of the peak concentration of the fifth injector in the end portion 105d of the first waveguide 105 can be well controlled by the injection process 341. For example, the peak concentration of the fifth injector may be located in the lower half of the end portion 105d of the first waveguide 105, or in the bottom third of the first waveguide 105. Alternatively, the concentration of the fifth injector in the lower half of the end portion 105d of the first waveguide 105 may be greater than the concentration in the upper half of the end portion 105d of the first waveguide 105. Therefore, compressive stress is generated in the upper half of the end portion 105d of the first waveguide 105. The end portion 105d of the first waveguide 105 bends upward from the main portion 105e to form a curved portion 105d'. In some embodiments, the curved portion 105d' may have a curved shape. In some embodiments, the curved portion 105d' of the first waveguide 105 may protrude above the second insulating layer 113, for example, overlapping the second waveguide 325 in the vertical direction. After the injection process 341, the mask layer 339 can be removed by any suitable method, such as by an etching process.

[0095] Reference Figure 18 After forming the curved portion 105d' of the first waveguide 105, according to some embodiments, a deposition process is performed to fill the recess 337 and encapsulate the curved portion 105d' of the first waveguide 105. The deposition process may provide the same material as the first insulating layer 103, the second insulating layer 113, and the third insulating layer 333. For example, the deposition process may include plasma-assisted chemical vapor deposition, other chemical vapor deposition processes, physical vapor deposition, combinations thereof, or similar deposition methods. Following deposition, a planarization process, such as CMP or mechanical polishing, may be selectively performed to remove excess material above the third insulating layer 333. If the mask layer 339 was not removed before the deposition process filling the recess 337, the mask layer 339 is removed after the planarization process.

[0096] Reference Figure 19According to some embodiments, after filling the groove 337, a third waveguide 345 is formed above the second insulating layer 113, and a fourth insulating layer 353 is formed above the third waveguide 345 and the third insulating layer 333. In one embodiment, the third waveguide 345 may be formed using materials and manufacturing methods similar to those used for the first waveguide 105 described above, such as depositing a material like silicon nitride using a chemical vapor deposition process. However, any suitable materials and manufacturing methods may be used. In some embodiments, one end of the third waveguide 345 is adjacent to a bend 105d' of the first waveguide 105, for example, there is a horizontal gap G2 between the third waveguide 345 and the bend 105d' of the first waveguide 105. The gap G2 is smaller than the gap G1. For example, the gap G2 may be from 0.1 micrometers to 0.9 micrometers. In one embodiment, the fourth insulating layer 353 may be formed using materials and forming methods similar to those used for the first insulating layer 103 described above, such as depositing a material like silicon dioxide using a deposition method such as low-temperature plasma-assisted chemical vapor deposition.

[0097] Reference Figure 20 After forming the third waveguide 345 and the fourth insulating layer 353, a groove 357 is formed to expose the end portion 345d of the third waveguide 345. The main portion 345e of the third waveguide 345 remains covered by the fourth insulating layer 353. In some embodiments, the end portion 345d of the third waveguide 345 has a length L5. The length L5 may be greater than the thickness of the third insulating layer 333, or greater than or equal to twice the thickness of the third insulating layer 333. For example, the length L5 may be from about 1 micrometer to about 30 micrometers. The length L5 may be the same as the length L4, although they may be different. The width W5 of the groove 357 is greater than the length L4 and extends into or through the second insulating layer 113. In some embodiments, the depth of the groove 357, measured from the upper surface of the third insulating layer 333, is greater than the length L5. The end portion 345d of the third waveguide 345 may be suspended in the groove 357.

[0098] The groove 357 can be formed by etching the fourth insulating layer 353, the third insulating layer 333, and the second insulating layer 113 according to a pattern of the mask layer 359. For example, the formation of the mask layer 359 may involve depositing a mask material on the fourth insulating layer 353 by any suitable deposition process and patterning the mask material by any suitable patterning process to form a pattern in the mask layer 359. The mask layer 359 may be a hard mask, such as titanium nitride, silicon nitride, silicon oxynitride, silicon carbide, other suitable materials, or combinations thereof. Alternatively, the mask layer 359 may be a photoresist material. The etching process for forming the groove 357 may include a wet etching process or a combination of a dry etching process followed by a wet etching process, using an etchant containing fluorine (e.g., HF, CF3, C2F2, etc.). The etching process may have high selectivity for the fourth insulating layer 353 and the third insulating layer 333 relative to the third waveguide 345.

[0099] Reference Figure 21 After forming the groove 357, an implantation process is performed on the end 345d of the third waveguide 345. During the implantation process, the first waveguide 105, the second waveguide 325, and other portions of the third waveguide 345 are masked by the mask layer 359. The implantation process may include implanting a sixth implant into the end 345d of the third waveguide 345. The sixth implant may contain nitrogen ions (N... + ), silicon ions (Si + Other suitable dopants or combinations thereof. The sixth implant can be delivered using an ion beam, with doses starting from approximately 1 × 10⁻⁶. 14 From atoms per square centimeter to approximately 1 × 10 16 Atoms per square centimeter, implantation energy from approximately 10 keV to approximately 50 keV, and temperature from approximately -50 degrees Celsius to approximately 200 degrees Celsius. Annealing is not required after implantation.

[0100] The depth of the peak concentration of the sixth implant in the end portion 345d of the third waveguide 345 can be well controlled by the implantation process. For example, the peak concentration of the sixth implant may be located in the upper half of the end portion 345d of the third waveguide 345, or in the top third third of the end portion 345d of the third waveguide 345. Alternatively, the concentration of the sixth implant in the upper half of the end portion 345d of the third waveguide 345 may be greater than the concentration in the lower half of the end portion 345d of the third waveguide 345. Therefore, compressive stress is generated in the lower half of the end portion 345d of the third waveguide 345. The end portion 345d of the third waveguide 345 bends downward from the main portion 345e to form a bent portion 345d'. In some embodiments, the bent portion 345d' of the third waveguide 345 may have a bent shape. The mask layer 359 used to form the groove 357 can be removed after the implantation process by any suitable process, such as by etching.

[0101] Because the curved portion 105d' of the first waveguide 105 bends upwards, while the curved portion 345d' of the third waveguide 345 bends downwards, the curved portion 345d' of the third waveguide 345 and the curved portion 105d' of the first waveguide 105 can be close to each other, or even overlap in the vertical direction. For example, the distance between the curved portion 345d' and the curved portion 105d' can be less than or equal to the distance D. Therefore, the curved portions 105d' of the first waveguide 105 and the curved portions 345d' of the third waveguide 345 can form a coupler 380. The coupler 380 can be an interlayer coupler, providing vertical interconnection for waveguides in different layers. In particular, the coupler 380 can connect waveguides in adjacent layers. For example, the coupler 380 can span two or more insulating layers (e.g., the second insulating layer 113 and the third insulating layer 333) to couple the first waveguide 105 located in the second insulating layer 113 to the third waveguide 345 located in the fourth insulating layer 353. In some embodiments, the waveguide in the intermediate layer (e.g., the second waveguide 325) is located vertically between the main portion 105e of the first waveguide 105 and the main portion 345e of the third waveguide 345. The presence of the second waveguide 325 does not cause crosstalk problems with the first waveguide 105 or the third waveguide 345 because it provides sufficient vertical distance (e.g., a distance equal to the thickness T3).

[0102] Figure 22 This is a cross-sectional view of an intermediate stage of an optical interconnect structure 400 according to some embodiments. The optical interconnect structure 400 can be formed using similar process steps to the optical interconnect structure 300, where similar element symbols represent similar feature components. In some embodiments of the optical interconnect structure 400, a second waveguide 325 located in the intermediate layer and adjacent to coupler 380 can also form a coupler with a higher-layer waveguide (e.g., a fourth waveguide 365) to provide a vertical optical interconnect. For example, one end of the second waveguide 325 can be implanted to form a curved portion 325d' extending upward from the main portion 325e of the second waveguide 325. The fourth waveguide 365 and the fifth insulating layer 373 can be formed above the fourth insulating layer 353. The formation of the fourth waveguide 365, the curved portion 365d' of the fourth waveguide 365, and the fifth insulating layer 373 can use references... Figures 19 to 21 The steps described are similar.

[0103] Because the curved portion 325d' of the second waveguide 325 bends upwards, while the curved portion 365d' of the fourth waveguide 365 bends downwards, the curved portions 325d' and 365d' can be close to each other, or even overlap in the vertical direction. The curved portions 325d' of the second waveguide 325 and 365d' of the fourth waveguide 365 can form a coupler 480. In some embodiments, the third waveguide 345 does not cause crosstalk with the second waveguide 325 or the fourth waveguide 365 because sufficient vertical distance is provided (e.g., a distance equal to the thickness T3). Although in Figure 22 Only four waveguides and two couplers are shown in the diagram. These embodiments are not intended to limit the application of more couplers and more waveguides in the optical interconnect structure 400.

[0104] In some embodiments, a cross-sectional view of an intermediate structure of a photonic integrated circuit (PIC) 500 is shown. The PIC 500 may include an electrical interconnect integrated with any one or any combination thereof of the aforementioned optical interconnect structures 100, 200, 300, or 400. For example, Figures 23 to 25 This illustrates an intermediate stage of a PIC with integrated optical interconnect structure 100 and electrical interconnect.

[0105] from Figure 23 Beginning, a substrate 501 similar to the substrate 101 described above is provided. An intermediate insulating layer 502 and an active layer 505 may be disposed above and supported by the substrate 501. In some embodiments, the substrate 501, the intermediate insulating layer 502, and the active layer 505 may together form part of a silicon-on-insulator (SOI) substrate at the start of the manufacturing process. In some embodiments, the (formed) active layer 505 includes one or more optical components 507. The intermediate insulating layer 502 may be a dielectric layer that separates the substrate 501 from the upper active layer 505, and in some embodiments, may additionally serve as part of a cladding material surrounding the optical components 507 in the active layer 505. In one embodiment, the intermediate insulating layer 502 may be silicon dioxide, silicon nitride, germanium oxide, germanium nitride, combinations thereof, or the like, deposited on the substrate 501 using deposition methods such as implantation (e.g., forming a buried oxide (BOX) layer) or chemical vapor deposition, atomic layer deposition, physical vapor deposition, etc. However, any suitable materials and manufacturing methods may be used.

[0106] The optical components 507 in the active layer 505 may include optical waveguides (e.g., ridge waveguides, rib waveguides, buried channel waveguides, diffused waveguides, etc.), couplers (e.g., grating couplers), directional couplers, optical modulators (e.g., Mach-Zehnder silicon photonic switches, microelectromechanical switches, microring resonators, etc.), amplifiers, multiplexers, demultiplexers, photoelectric converters (e.g., PN junctions, electro-optic converters, lasers, combinations thereof, or similar elements). In some embodiments, the material of the active layer 505 may be a light-transmitting material, which may be used as the core material of the desired optical component 507, such as a semiconductor material (e.g., silicon, germanium, silicon-germanium, combinations thereof, or the like). In other embodiments, the material of the active layer 505 may be a dielectric material (e.g., silicon nitride or the like). In other embodiments, the material of the active layer 505 may be a III-V group material, lithium niobate, or a polymer. The material may be patterned into the desired shape for various optical components.

[0107] Once the optical component 507 with active layer 505 is formed, a first insulating layer 509 may be deposited to cover the optical component 507. In some embodiments, the first insulating layer 509 may be a dielectric layer that separates the individual elements of the active layer 505 from each other and the structure above, and may additionally serve as another part of the covering material surrounding the optical component 507. In one embodiment, the first insulating layer 509 may be formed by depositing a material such as silicon dioxide using a deposition method such as low-temperature plasma-assisted chemical vapor deposition. However, any suitable material and manufacturing method may be used.

[0108] Reference Figure 24 A first waveguide 105, its curved portion 105a', and a first metallized component 517 are disposed above a first insulating layer 509. In some embodiments, a patterned material of the first waveguide 105 is formed above the first insulating layer 509, and a second insulating layer 519 is formed above the material of the first waveguide 105. Similar to reference... Figures 3 to 5The described steps involve forming the bent portion 105a' by creating a groove to expose the end of the first waveguide 105 and performing an injection process on the end of the first waveguide 105. The groove for exposing the end of the first waveguide 105 can be refilled with the material of the second insulating layer 519. A first metallization member 517 can be formed in the second insulating layer to electrically connect the optical components 507 in the active layer 505 to control circuitry, to each other, and to any device connected to the PIC 500. The first metallization member 517 can be formed by any suitable method, such as by a single or dual damascene process after the formation of the second insulating layer 519. In some embodiments, the first metallization member 517 can be formed prior to forming the bent portion 105a' of the first waveguide 105. In this embodiment, the first metallization member 517 can be masked by a mask layer such as mask layer 119 during the step of forming the bent portion 105a'. Alternatively, the bent portion 105a' of the first waveguide 105 may be formed prior to the formation of the first metallization component 517. In this embodiment, the bent portion 105a' is masked by a mask layer during any etching step in forming the first metallization component 517 in the second insulating layer 519.

[0109] Reference Figure 25 According to some embodiments, an additional layer of electrical interconnection and an additional layer of optical interconnection are provided in the PIC 500. For example, a second waveguide 125 and its bent portion 125a' and a second metallization member 537 are formed over a first insulating layer 509. In some embodiments, the second waveguide 125 is formed over the first insulating layer 509, and a third insulating layer 539 is formed over the second waveguide 125. Similar to reference... Figures 7 to 9 The described steps involve forming the bent portion 125a' by creating a groove to expose the end of the second waveguide 125 and performing an injection process on the end of the second waveguide 125. The groove for exposing the end of the second waveguide 125 can be refilled with the material of the third insulating layer 539. A second metallization member 537 can be formed in the third insulating layer 539, and the second metallization member 537 contacts the first metallization member 517 for electrical connection. Not only can the metallization members 517 and 537 provide vertical interconnection, but the first waveguide 10 and the second waveguide 125 can also provide vertical optical interconnection via a coupler formed by the bent portion 105a' and the bent portion 125a'.

[0110] The second metallized component 537 can be formed by any suitable method, such as by a single or dual damascene process after the formation of the third insulating layer 539. In some embodiments, the second metallized component 537 may be formed prior to the formation of the bent portion 125a' of the second waveguide 125. In this embodiment, the second metallized component 537 may be masked by a mask layer such as mask layer 139 during the step of forming the bent portion 125a'. Alternatively, the bent portion 125a' of the second waveguide 125 may be formed prior to the formation of the second metallized component 537. In this embodiment, the bent portion 125a' is masked by a mask layer during any etching step of forming the second metallized component 537 in the third insulating layer 539.

[0111] Therefore, the PIC 500 can provide integration of electrical interconnects (e.g., first metallization component 517 and second metallization component 537) and optical interconnects (e.g., optical interconnect structure 100). For example, the optical interconnect structure 100 in the PIC 500 may include couplers that operate like conductive vias in electrical interconnects for interlayer signal transmission. Electrical and optical interconnects can share the same insulating layer. Therefore, the routing design complexity of electrical and optical interconnects can be reduced. Furthermore, since the fabrication process for optical interconnects can be independent of that of electrical interconnects, the fabrication of optical interconnects can be compatible with various electrical interconnects.

[0112] In one embodiment, a method of manufacturing an optical device includes forming a first waveguide in a first insulating layer above a substrate, wherein the first waveguide includes a first main portion and a first curved portion, the first curved portion extending upward from the first main portion and away from the substrate; and forming a second waveguide above the first waveguide, wherein the second waveguide includes a second main portion and a second curved portion, the second main portion being located above the first insulating layer, and the second curved portion extending downward from the second main portion and into the first insulating layer. In one embodiment, the first curved portion of the first waveguide overlaps with the second curved portion of the second waveguide in a vertical direction. In one embodiment, forming the first waveguide in the first insulating layer includes forming a patterned material of the first waveguide; forming the first insulating layer above the patterned material of the first waveguide; forming a first groove to expose the end of the patterned material of the first waveguide, wherein the portion of the first waveguide not exposed by the first groove forms the main portion of the first waveguide; and forming the first curved portion of the first waveguide by injecting the end of the patterned material of the first waveguide into the first injector. In one embodiment, the first injector has a peak concentration in the lower half of the first curved portion of the first waveguide. In one embodiment, the method of manufacturing the optical device further includes filling a first groove with material of a first insulating layer after forming a first curved portion of a first waveguide. In one embodiment, forming a second waveguide includes forming a patterned material of the second waveguide over the first insulating layer; forming a second insulating layer over the patterned material of the second waveguide; forming a second groove in the second insulating layer and the first insulating layer to expose a second end of the second waveguide, wherein the portion of the second waveguide not exposed by the second groove forms a second main portion of the second waveguide; and forming a second curved portion of the second waveguide by injecting the second end of the patterned material of the second waveguide into a second injector. In one embodiment, the second injector has a peak concentration in the upper half of the second curved portion of the second waveguide.

[0113] In another embodiment, a method of manufacturing an optical device includes forming a first waveguide above a substrate; forming a first insulating layer covering the first waveguide and located above the substrate; forming a first groove in the first insulating layer to expose a first end of the first waveguide; performing a first injection process on the first end of the first waveguide to form a first curved portion of the first waveguide, wherein the first curved portion bends upward relative to a portion of the first waveguide not exposed by the first groove; forming a second waveguide above the first insulating layer, wherein there is a horizontal gap between the second waveguide and the first curved portion of the first waveguide; forming a second insulating layer covering the second waveguide and located above the first insulating layer; forming a second groove in the second insulating layer and the first insulating layer to expose a second end of the second waveguide, the second end of the second waveguide being adjacent to the first curved portion of the first waveguide; and performing a second injection process on the second end of the second waveguide to form a second curved portion of the second waveguide, wherein the second curved portion bends downward relative to a portion of the second waveguide not exposed by the second groove. In one embodiment, a first injection process injects a first injectant into a first end of a first waveguide. After the first injection process, the concentration of the first injectant provided in the lower half of the first end of the first waveguide is greater than the concentration of the first injectant in the upper half of the first end of the first waveguide. In one embodiment, the first injectant contains N... + Si + Or a combination thereof. In one embodiment, the second implantation process includes implanting a second injectant into a second end of the second waveguide, the second implantation process providing a higher concentration of the second injectant in the upper half of the second end of the second waveguide than in the lower half of the second end of the second waveguide. In one embodiment, the first injectant is the same as the second injectant, and the first implantation process and the second implantation process provide different implantation energies. In one embodiment, the width of the first groove is greater than the length of the first end of the first waveguide. In one embodiment, forming the first groove includes forming a mask layer over a first insulating layer and etching the first insulating layer according to a pattern of the mask layer, and removing the mask layer after performing the first implantation process.

[0114] In another embodiment, an optical device includes a first insulating layer located above a substrate; a first waveguide located within the first insulating layer, wherein the first waveguide includes a main portion and a first curved portion extending upward from the first main portion and away from the substrate; and a second waveguide located above the first waveguide, wherein the second waveguide includes a second main portion and a second curved portion, the second main portion being located above the first insulating layer, and the second curved portion extending downward from the second main portion and into the first insulating layer. In one embodiment, the first curved portion of the first waveguide overlaps with the second curved portion of the second waveguide in a vertical direction. In one embodiment, the first curved portion of the first waveguide includes a first injector, wherein the first injector has a peak concentration in the lower half of the first curved portion of the first waveguide. In one embodiment, the first injector includes N... + Si + Or a combination thereof. In one embodiment, the second bend of the second waveguide includes a second injector having a peak concentration in the upper half of the second bend of the second waveguide. In one embodiment, a first major portion of the first waveguide is parallel to a second major portion of the second waveguide.

[0115] The foregoing outlines the features of numerous embodiments, enabling those skilled in the art to better understand the present invention from various aspects. Those skilled in the art will understand that other processes and structures can be easily designed or modified based on the present invention to achieve the same purpose and / or the same advantages as the embodiments described herein. Those skilled in the art will also understand that these equivalent structures do not depart from the spirit and scope of the present invention. Various changes, substitutions, or modifications can be made to the present invention without departing from its spirit and scope.

Claims

1. An optical device, characterized in that, The optical device includes: The first insulating layer is located above the substrate; A first waveguide, located within the first insulating layer, wherein the first waveguide includes a first main portion and a first curved portion, the first curved portion extending upward from the first main portion and away from the substrate; and A second waveguide is located above the first waveguide, wherein the second waveguide includes a second main portion and a second curved portion, the second main portion being located above the first insulating layer, and the second curved portion extending downward from the second main portion and into the first insulating layer.

2. The optical device as claimed in claim 1, characterized in that, The first curved portion of the first waveguide overlaps with the second curved portion of the second waveguide in the vertical direction.

3. The optical device as claimed in claim 1, characterized in that, The first main portion of the first waveguide is parallel to the second main portion of the second waveguide.

4. The optical device as claimed in claim 1, characterized in that, The second curved portion forms a coupler with the first curved portion.

5. The optical device as claimed in claim 1, characterized in that, The first curved portion extends vertically above half the thickness between the upper surface of the first insulating layer and the upper surface of the first main portion.

6. The optical device as claimed in claim 1, characterized in that, The optical device further includes: A second insulating layer is located above the first insulating layer, wherein the second main portion is located within the second insulating layer.

7. The optical device as claimed in claim 6, characterized in that, The second waveguide also includes a third curved portion that extends upward from the second main portion.

8. The optical device as claimed in claim 7, characterized in that, The third curved portion extends vertically above half the thickness between the upper surface of the second insulating layer and the upper surface of the second main portion.

9. The optical device as claimed in claim 7, characterized in that, The optical device further includes: A third waveguide is located above the second waveguide, wherein the third waveguide includes a third main portion and a fourth curved portion, the third main portion being located above the second insulating layer, and the fourth curved portion extending downward from the third main portion and into the second insulating layer.

10. The optical device as claimed in claim 9, characterized in that, The third curved portion and the fourth curved portion form a coupler.

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