package

Abstract

Embodiments of the present disclosure describe a package. The package includes a photonic die including a waveguide in a cladding layer, a first grating coupler, and a second grating coupler. The first grating coupler and the second grating coupler have a gap in a first direction, where the first grating coupler has a first end and a second end in a second direction perpendicular to the first direction. The photonic die further includes a first optical protection structure through the cladding layer disposed in the gap and extending beyond the first end and the second end of the first grating coupler in the second direction. The package further includes an interconnect structure disposed in a first dielectric layer and a second dielectric layer over the cladding layer, an electronic die including circuitry electrically coupled to the interconnect structure, and an insulating layer laterally surrounding the electronic die.

Description

Technical Field

[0001] This disclosure relates to a package. Background Technology

[0002] Electrical signal processing is a technology for signal transmission and processing. In recent years, the application of optical signal processing has become increasingly widespread, especially due to the use of fiber optics for signal transmission.

[0003] Optical signals and processing are often combined with electrical signals and processing to provide mature 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. This results in devices that integrate optical elements and electrical components for the conversion and processing of optical and electrical signals. Therefore, the package can include optical (photonic) chips with optical devices and electronic chips with electronic devices. Utility Model Content

[0004] An enclosure includes a photonic die, an electronic die, and an insulating layer. The photonic die includes a waveguide, a first grating coupler, a second grating coupler, a first optical protection structure, and an interconnect structure. The waveguide is disposed within the cladding layer. The first and second grating couplers are disposed within the cladding layer, with a gap in a first direction between them. The first grating coupler has a first end and a second end, the second end being opposite to the first end in a second direction perpendicular to the first direction. The first optical protection structure extends through the cladding layer and through the gap between the first and second grating couplers, extending in the second direction over the first and second ends of the first grating coupler. The interconnect structure is on the cladding layer, including a connection layer disposed within the first and second dielectric layers. The electronic die includes a plurality of circuits electrically coupled to the connection layer of the interconnect structure. An insulating layer laterally surrounds the electronic die.

[0005] A package includes a photonic chip, an electronic chip, and an insulating layer. The photonic chip includes a waveguide, a first grating coupler, a second grating coupler, and an interconnect structure. A waveguide is disposed within a cladding layer; a first grating coupler and a second grating coupler are disposed within the cladding layer, wherein a gap exists between the first grating coupler and the second grating coupler in a first direction, wherein the first grating coupler has a first end and a second end, the second end being opposite to the first end in a second direction perpendicular to the first direction; and an interconnect structure is disposed on the cladding layer, the interconnect structure including a first dielectric layer, a second dielectric layer, a connection layer, a first optical protection structure, and a second optical protection structure, the second dielectric layer being on the first dielectric layer; the connection layer is disposed within the first and second dielectric layers; the first optical protection structure is disposed within the first dielectric layer, wherein the first optical protection structure extends between the first grating coupler and the second grating coupler and over the first and second ends of the first grating coupler in a second direction in a planar viewing angle; and the second optical protection structure is disposed within the second dielectric layer and overlaps the first optical protection structure in a planar viewing angle. An electronic die includes a plurality of circuits electrically coupled to the connection layer of the interconnect structure. An insulating layer laterally surrounds the electronic die.

[0006] An enclosure includes a photonic die, an electronic die, a second optical protection structure, and a third optical protection structure. The photonic die includes a waveguide, a first grating coupler, a second grating coupler, the first optical protection structure, and an interconnect structure. The waveguide is disposed within a cladding layer. The first and second grating couplers are disposed within the cladding layer, with a gap in a first direction between them. The first grating coupler has a first end and a second end, the second end being opposite to the first end in a second direction perpendicular to the first direction. The first optical protection structure extends through the cladding layer and the gap between the first and second grating couplers, extending in the second direction over the first and second ends of the first grating coupler. The interconnect structure is on the cladding layer, including a connection layer disposed within a first and a second dielectric layer. The electronic die includes a plurality of circuits electrically coupled to the connection layer of the interconnect structure. The second optical protection structure is disposed within the first dielectric layer. A third optical protection structure is disposed within the second dielectric layer, wherein the third optical protection structure is disposed above the second optical protection structure. In a planar view, the second and third optical protection structures overlap the gap between the first optical protection structure and the first and second grating couplers. Attached Figure Description

[0007] The various aspects of this disclosure can be best understood by reading the following detailed description in conjunction with the accompanying drawings. It is important to note that, in accordance with industry standard practice, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased.

[0008] Figures 1 to 5 , Figure 7 and Figures 9 to 11 Cross-sectional views of intermediate steps in forming a photonic package are shown according to some implementation methods;

[0009] Figure 6A to Figure 6L A plan view of the optical protection structure and grating coupler is shown according to some implementation methods;

[0010] Figure 8A and Figure 8B Cross-sectional and plan views of the optical protection structure and grating coupler are shown according to some implementation methods;

[0011] Figure 12 Cross-sectional views of intermediate steps of a photonic package are shown according to some implementation methods;

[0012] Figure 13 Cross-sectional views of intermediate steps of a photonic package are shown according to some implementation methods;

[0013] Figure 14 A cross-sectional view of an intermediate step of a photonic package is shown according to some implementation methods.

[0014] [Symbol Explanation]

[0015] 100: Photonic Encapsulation

[0016] 101: Photonic Grain

[0017] 102:Substrate

[0018] 102A: Device Layer

[0019] 102B: Insulation layer, buried oxide layer

[0020] 102C: Bulk substrate, silicon substrate

[0021] 104: Waveguide

[0022] 106: Photonic elements

[0023] 108: Grating Coupler

[0024] 108A: First grating coupler

[0025] 108A1: First end

[0026] 108A2: Second end

[0027] 108B: Second grating coupler

[0028] 108B1: First end

[0029] 108B2: Second end

[0030] 110: Covering layer

[0031] 112: Opening

[0032] 114: Through hole

[0033] 116: Contact

[0034] 118: First optical protection structure

[0035] 118A: First optical isolation

[0036] 118A1: First end

[0037] 118A2: Second end

[0038] 118B: Second optical isolation

[0039] 118B1: First end

[0040] 118B2: Second end

[0041] 118C: Shared Part

[0042] 120: Interconnection Structure

[0043] 122: First dielectric layer

[0044] 124: Second dielectric layer

[0045] 126: Third dielectric layer

[0046] 127: Dielectric layer

[0047] 128: Connector Layer

[0048] 130: Conductive plate

[0049] 132: Second optical protection structure

[0050] 132A: First optical isolation

[0051] 132B: Second optical isolation

[0052] 134: Third optical protection structure

[0053] 134A: First optical isolation

[0054] 134B: Second optical isolation

[0055] 136: Fourth optical protection structure

[0056] 136A: First optical isolation

[0057] 136B: Second optical isolation

[0058] 140A: First Optical Path

[0059] 140B: Second optical path

[0060] 144: Electronic grain

[0061] 146: Die connector

[0062] 148: Dielectric bonding layer

[0063] 150: Insulation layer

[0064] 152: Conductive plate

[0065] 154: Conductive Connector

[0066] 156: Supporting substrate

[0067] 160: External photonic element

[0068] 164: Dummy Grains

[0069] 164A:Substrate

[0070] 166: Dielectric bonding layer

[0071] 168: Fifth optical protection structure

[0072] 168A: First optical isolation

[0073] 168B: Second optical isolation

[0074] 170: Sixth optical protection structure

[0075] 170A: First optical isolation

[0076] 170B: Second optical isolation

[0077] 174: Seventh Optical Protection Structure

[0078] 174A: First optical isolation

[0079] 174B: Second optical isolation

[0080] OL, L1, L2: Length

[0081] D: Distance

[0082] G: Gap

[0083] W: Width

[0084] T: Thickness Detailed Implementation

[0085] The following disclosure provides many different implementations or examples for performing the various main features provided. Specific components and configuration examples are described below to simplify this disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature on or over a second feature described may include implementations where the first and second features are formed in direct contact, and may also include implementations where additional features may be formed within the first and second features so that the first and second features are not in direct contact. Furthermore, references to numbers and / or letters may be repeated in various instances. This repetition is for simplification or clarity and does not specify the relationship between the various implementations and / or configurations discussed.

[0086] Furthermore, spatially related terms, such as "below," "lower part," "above," and "upper part," are used here to simply describe the relationship of one element or feature to other elements or features illustrated in the diagram. Spatially related terms are intended to include the orientation of different devices in use or operation. Instruments may have other orientations (rotated 90 degrees or other orientations), and spatially related descriptions used here are subject to interpretation.

[0087] This disclosure describes a package and various aspects of its formation. According to some embodiments, a package including optical elements and electrical devices, and a method for forming the same, is provided. Specifically, the photonic package may include a grating coupler as an interface for transmitting optical signals to or receiving optical signals from an external photonic device. This disclosure provides an optical protection structure that can be disposed around the optical path leading to the grating coupler, effectively reducing interference between optical signals. Therefore, the photonic package may include an increased density of grating couplers while reducing optical signal transmission noise. According to some embodiments, intermediate stages of package formation are shown. Some variations of some embodiments are discussed. In the various views and illustrative embodiments, the same reference numerals are used to denote the same elements.

[0088] Figures 1 to 5 , Figure 7 and Figures 9 to 11 A diagram illustrating the formation of a photonic package 100 is shown according to some embodiments (see...). Figure 11 A cross-sectional view of an intermediate step in the process. The photonic package 100 may be part of a computing system. Figures 1 to 8B The formation of the photonic die 101 can be described. In some embodiments, the photonic package 100 provides an input / output (I / O) interface between optical and electrical signals in a computing system. In some embodiments, the photonic package 100 provides an optical network for signal communication between components within the photonic package 100 (e.g., photonic devices, integrated circuits, couplers to external optical fibers, etc.).

[0089] First, let's go back to... Figure 1According to some embodiments, a substrate 102 is provided. The substrate 102 may include a device layer 102A, an insulating layer 102B, and a bulk substrate 102C. The device layer 102A may be disposed above the insulating layer 102B, and the insulating layer 102B may be disposed above the bulk substrate 102C. In some embodiments, the device layer 102A may include silicon, a silicon compound (e.g., silicon germanium), silicon nitride, or other suitable materials suitable for forming photonic devices. In one embodiment, the insulating layer 102B includes an oxide (e.g., silicon oxide) or other suitable dielectric material. In some embodiments, the device layer 102A has a thickness of about 0.1 μm to about 1.5 μm, and the insulating layer 102B has a thickness of about 0.5 μm to about 4 μm. Other thicknesses may also be used. The bulk substrate 102C may be, for example, a glass, ceramic, dielectric, semiconductor, or a combination thereof. The bulk substrate 102C may be a wafer, such as a silicon wafer, and the photonic package 100 may be diced in subsequent manufacturing steps. In some embodiments, the bulk substrate 102C is a semiconductor substrate that is doped (e.g., with p-type or n-type dopants) or undoped. For example, the semiconductor material of the bulk substrate 102C may include silicon; germanium; compound semiconductors including silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and / or indium antimonide; alloy semiconductors including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and / or GaInAsP; or combinations thereof. The bulk substrate 102C may include a multilayer composition or a gradient composition. In some embodiments, substrate 102 is a buried oxide (“BOX”) substrate. The BOX substrate includes a buried oxide layer 102B disposed over the silicon substrate 102C and a device layer 102A disposed over the buried oxide layer 102B.

[0090] According to some implementation methods, in Figure 2In this embodiment, device layer 102A is patterned to form waveguide 104, photonic element 106, and grating coupler 108. In some embodiments, other types of couplers (not separately labeled in the figures) may be formed in device layer 102A. Device layer 102A may be patterned using suitable photolithography and etching techniques. For example, in some embodiments, a hard mask layer (e.g., a nitride layer or other dielectric material, not shown in Figure 2) may be formed over device layer 102A and patterned thereon. The pattern of the hard mask layer may then be transferred to device layer 102A using an etching process. The etching process may include, for example, dry etching and / or wet etching processes. For example, device layer 102A may be etched to form a recess defining waveguide 104, wherein the sidewalls of the remaining unrecessed portion define the sidewalls of waveguide 104. In some embodiments, more than one photolithography and etching sequence may be used to pattern device layer 102A. One or more waveguides 104 may be patterned from device layer 102A. If multiple waveguides 104 are formed, the multiple waveguides 104 can be individual separate waveguides 104 or connected into a single continuous structure. In some embodiments, one or more waveguides 104 form a continuous loop.

[0091] Photonic element 106 may be integrated with waveguide 104 and may be formed together with silicon waveguide 104. Photonic element 106 may be optically coupled to waveguide 104 to interact with optical signals within waveguide 104. Photonic element 106 may include photonic devices such as photodetectors and / or modulators. For example, a photodetector may be optically coupled to waveguide 104 to detect optical signals within waveguide 104 and generate an electrical signal corresponding to the optical signal. A modulator may be optically coupled to waveguide 104 to receive the electrical signal and generate a corresponding optical signal within waveguide 104 by modulating the optical power within waveguide 104. In this way, photonic element 106 facilitates input / output (I / O) between optical signals and waveguide 104. In other embodiments, photonic element may include other active or passive components, such as laser diodes, optical signal splitters, or other types of photonic structures or devices. Optical power can be provided to waveguide 104 by, for example, an external photonic element 160, or optical power can be generated by a photonic element within photonic package 100, such as a laser diode (not shown).

[0092] In some embodiments, a photodetector can be formed, for example, by partially etching a region of waveguide 104 and growing epitaxial material on the remaining silicon in the etched region. Waveguide 104 can be etched using acceptable photolithography and etching techniques. The epitaxial material can include semiconductor materials such as germanium, which can be doped or undoped. In some embodiments, an implantation process can be performed to introduce dopants into the silicon in the etched region as part of the photodetector formation. The silicon in the etched region can be doped with p-type dopants, n-type dopants, or a combination of both. In some embodiments, a modulator can be formed, for example, by partially etching a region of waveguide 104 and then implanting an appropriate dopant into the remaining silicon in the etched region. Waveguide 104 can be etched using acceptable photolithography and etching techniques. In some embodiments, the etched region for the photodetector and the etched region for the modulator can be formed using one or more of the same photolithography or etching steps. The silicon in the etched region can be doped with p-type dopants, n-type dopants, or a combination of both. In some embodiments, the etched region for the photodetector and the etched region for the modulator can be implanted using one or more of the same implantation steps.

[0093] In some implementations, multiple grating couplers 108 are integrated with waveguide 104. Although Figure 2 Only the first grating coupler 108A and the second grating coupler 108B are shown in the diagram, but more grating couplers 108 can be used. For example, the grating couplers can be arranged in a matrix in a planar diagram. In other words, they can be arranged in a matrix. Figure 2 On the cross section shown and / or perpendicular to Figure 2More grating couplers are arranged in the direction of the cross-section shown. The grating coupler 108 is a photonic structure that allows optical signals and / or optical power to be transmitted between photonic devices (e.g., waveguide 104 and / or photonic element 106) in device layer 102A and photonic elements disposed outside device layer 102A. The grating coupler 108 can be formed using acceptable photolithography and etching techniques. In one embodiment, the grating coupler 108 is formed after waveguide 104 is defined. For example, photoresist can be formed on waveguide 104 and device layer 102A. The photoresist can be patterned to have openings corresponding to the grating coupler 108. One or more etching processes can be performed using the patterned photoresist as an etching mask to form grooves defining the grating coupler 108 in waveguide 104. The etching processes may include one or more dry etching processes and / or wet etching processes. The aforementioned photonic devices are considered to be within the scope of this disclosure. Other configurations or arrangements of waveguide 104, photonic element 106, grating coupler 108, and / or other couplers are also possible, and other types of photonic element 106 can be formed. In some embodiments, the first grating coupler 108A and the second grating coupler 108B have a gap G of about 0.5 mm or less, but gaps greater than about 0.5 mm can also be achieved. However, it has been found that when adjacent grating couplers 108 are too close together (e.g., gap G is less than about 0.5 mm), adjacent grating couplers 108 (e.g., the first grating coupler 108A and the second grating coupler 108B) may encounter optical interference problems.

[0094] Referring again to FIG3, according to some embodiments, a cladding layer 110 is formed on the front side of the substrate 102. The cladding layer 110 may cover the waveguide 104, photonic element 106, grating coupler 108, and insulating layer 102B. The cladding layer 110 may be formed from one or more layers of silicon oxide, silicon nitride, or combinations thereof, and may be formed by CVD, PVD, atomic layer deposition (ALD), spin-coating dielectric processes, or combinations thereof. In some embodiments, the cladding layer 110 is formed by high-density plasma chemical vapor deposition (HDP-CVD), flowable CVD (FCVD) (e.g., depositing a CVD-based material in a remote plasma system and post-curing it to form a material that transforms into another material, such as an oxide), or a combination thereof. Other dielectric materials formed by any acceptable process may be used. In some embodiments, the cladding layer 110 is planarized using a planarization process (e.g., chemical mechanical polishing (CMP), grinding, etc.). The cladding layer 110 may be formed over the insulating layer 102B with a thickness of, for example, from about 50 nm to about 500 nm, or over the waveguide 104 with a thickness of, for example, from about 10 nm to about 200 nm.

[0095] Because the waveguide 104 and the cladding layer 110 have different refractive indices, the waveguide 104 exhibits high internal reflection, effectively confining light within the waveguide 104, depending on the wavelength of the light and the refractive index of the corresponding material. In one embodiment, the refractive index of the waveguide 104 material is higher than that of the cladding layer 110 material. For example, when the waveguide 104 is silicon, the cladding layer 110 may be silicon oxide and / or silicon nitride.

[0096] According to some implementation methods, in Figure 4 In the embodiment, opening 112 is formed to extend into the bulk substrate 102C. Opening 112 is formed to penetrate the cladding layer 110 and the insulating layer 102B. Opening 112 also partially extends into the bulk substrate 102C. Opening 112 can be formed by acceptable photolithography and etching techniques, such as by forming and patterning photoresist, and then using the patterned photoresist as an etching mask to perform an etching process. The etching process may include, for example, dry etching and / or wet etching processes.

[0097] According to some implementation methods, in Figure 5 In the process, a conductive material is formed in the opening 112, thereby forming a conductive via 114 extending into the bulk substrate 102C. In some embodiments, a pad (not shown), such as a diffusion barrier layer, an adhesion layer, etc., may be formed in the opening 112, and a suitable deposition process, such as CVD, ALD, etc., may be used. The pad may include TaN, Ta, TiN, Ti, CoW, combinations thereof, etc. In some embodiments, a seed layer (not shown) may then be deposited in the opening 112, which may include titanium, copper, alloys thereof, or combinations thereof. The conductive material of the conductive via 114 in the opening 112 is formed, for example, using electrochemical plating (ECP), chemical plating, PCVD, CVD, or other suitable methods. The conductive material may include metals or metal alloys of copper, silver, gold, tungsten, cobalt, and aluminum. A planarization process (e.g., CMP or grinding process) can be performed to remove excess conductive material on the top surface of the coating layer 110, so that the top surfaces of the conductive via 114 and the coating layer 110 are flush with each other.

[0098] Figure 5 The formation of contacts 116, which penetrate the cladding layer 110 and are electrically connected to the photonic element 106, is also shown. Contacts 116 (also referred to as vias) allow power or electrical signals to be transmitted to and from the photonic element 106. In this way, the photonic element 106 can transmit electrical signals (e.g., from the electronic chip 144, see...) Figure 9The optical signal from waveguide 104 is converted into an optical signal transmitted by waveguide 104, and / or the optical signal from waveguide 104 and grating coupler 108 is converted into an electrical signal (e.g., which can be received by electronic die 144). Contact 116 may be formed before or after the formation of conductive via 114, and the formation of contact 116 and conductive via 114 may share some steps, such as deposition and / or planarization of conductive material. In some embodiments, the contact may be formed by a damascene process, such as single damascene, double damascene, etc. For example, in some embodiments, an opening (not shown) for contact 116 is first formed in the cladding layer 110 using acceptable photolithography and etching techniques. Conductive material can then be formed in the opening to form contact 116. Excess conductive material can be removed using a CMP process, etc. The conductive material of contact 116 may be formed of a metal or metal alloy, including aluminum, copper, tungsten, etc., and may be the same material as the conductive via 114. In other embodiments, other techniques or materials may be used to form contact 116.

[0099] exist Figure 5 In some embodiments, a first optical protection structure 118 is formed in the cladding layer 110. The first optical protection structure 118 may include a first optical isolation 118A and a second optical isolation 118B. The first optical protection structure 118 may have a pattern capable of substantially blocking optical interference, such as reducing noise from non-perpendicular or lateral light, thereby enabling the first grating coupler 108A and the second grating coupler 108B to receive noise-reduced optical signals even when close together. The first optical protection structure 118 may be a via. For example, the first optical protection structure 118 may be formed by the inlay process described in forming the conductive via 114 or the contact 116. The first optical protection structure 118 may be formed before or after the formation of the contact 116 and / or the conductive via 114. And the formation of the contact 116 and / or the conductive via 114 may share some steps, such as the deposition and / or planarization of conductive material.

[0100] Figure 6A to Figure 6LAn exemplary pattern of the first optical protection structure 118 is shown in planar view. The first grating coupler 108A and the second grating coupler 108B may have a gap G in a first direction (e.g., the X-axis shown in FIG. 6A). The first grating coupler 108A and the second grating coupler 108B may have a length L1 in a second direction perpendicular to the first direction (e.g., the Y-axis shown in FIG. 6A). For example, the first grating coupler 108A may have a first end 108A1 and a second end 108A2 opposite to the first end 108A1, and the second grating coupler 108B may have a first end 108B1 and a second end 108B2 opposite to the first end 108B1. The first optical protection structure 118 may extend at least beyond the first end 108A1 and the second end 108A2 of the first grating coupler 108A. In some embodiments, a first optical isolation 118A is disposed between a first grating coupler 108A and a second grating coupler 108B, extending above a first end 108A1 and a second end 108A2 of the first grating coupler 108A. A second optical isolation 118B may be disposed between the first grating coupler 108A and the second grating coupler 108B, extending across a first end 108B1 and a second end 108B2 of the second grating coupler 108B. In one embodiment, the first optical isolation 118A extends towards the first grating coupler 108A in a portion other than the first end 108A1 and / or the second end 108A2, or extends towards the first grating coupler 108A in a portion other than the first end 108A1 and / or the second end 108A2. Furthermore, the second optical isolation 118B extends into the second grating coupler 108B in a portion thereof, exceeding the first end 108A1 and / or the second end 108A2 of the first grating coupler 108A or the first end 108B1 and / or the second end 108B2 of the second grating coupler 108B. In some embodiments, the total length L2 of the first optical isolation 118A and the second optical isolation 118B in the second direction is at least twice (or approximately five times) the length L1 of the first grating coupler 108A in the second direction (or the total length of the first grating coupler 108A and the second grating coupler 108B).

[0101] In some embodiments, the first optical isolator 118A and the second optical isolator 118B each have a shape that laterally surrounds the first grating coupler 108A and the second grating coupler 108B, respectively. For example, the first optical isolator 118A and the second optical isolator 118B have a closed circular shape as shown in FIG. 6A, a closed elliptical ring shape as shown in FIG. 6B, a closed rectangular or closed square shape as shown in FIG. 6C, or a closed pentagon as shown in FIG. 6D. It is understood that the first optical isolator 118A and the second optical isolator 118B can be implemented in any type of ring or polygon. In some embodiments, each of the first optical isolator 118A and the second optical isolator 118B has a width W of approximately greater than 5 angstroms. It should also be understood that the size and / or shape of the first optical isolator 118A and the second optical isolator 118B may be different.

[0102] Although Figures 6A to 6D show the first optical isolation 118A and the second optical isolation 118B as having a closed shape, according to some embodiments, at least one of the first optical isolation 118A and the second optical isolation 118B has an open end. For example, Figures 6E to... Figure 6H The diagram shows a first optical isolation 118A and a second optical isolation 118B, each having a shape corresponding to that in Figures 6A to 6D, and both having open ends. The open ends can be located away from adjacent grating couplers. For example, in Figures 6E to... Figure 6H In this configuration, the first optical isolator 118A has an open end located away from the second grating coupler 108B, and the second optical isolator 118B has an open end located away from the first grating coupler 108A. The distance D between the open ends of the first optical isolator 118A and the second optical isolator 118B can be varied. In some embodiments, the distance D between the open ends of the first optical isolator 118A or the second optical isolator 118B is less than the length L1 of the first grating coupler 108A or the second grating coupler 108B, although the distance D can also be greater than the length L1 of the first grating coupler 108A or the second grating coupler 108B.

[0103] In some embodiments, as shown in Figures 6I and 6J, at least one of the first optical isolation 118A and the second optical isolation 118B is a linear wall. The total length L2 of the linear wall can be at least twice (or five times) the length L1 of the first grating coupler 108A or the second grating coupler 108B to sufficiently block interference between adjacent optical signals directed to the first grating coupler 108A and the second grating coupler 108B, respectively. As shown in Figure 6I, the linear wall of the first optical isolation 118A or the second optical isolation 118B can extend in only one direction and be located between the first grating coupler 108A and the second grating coupler 108B. Alternatively, the linear wall can also extend in other directions to block optical interference from different directions. For example, as shown in Figure 6J, the first optical isolation 118A can extend above the upper side of the first grating coupler 108A, while the second optical isolation 118B can extend below the lower side of the second grating coupler 108B.

[0104] The first optical isolator 118A and the second optical isolator 118B can be separated from or connected to each other. For example, in some embodiments, the first optical isolator 118A and the second optical isolator 118B are connected and have a shared portion. Taking FIG6K as an example, both the first optical isolator 118A and the second optical isolator 118B have a circular shape and have a shared portion 118C. In some embodiments, the first optical isolator 118A and the second optical isolator 118B can be misaligned in a second direction (e.g., the Y-axis), as shown in FIG6L. For example, as Figure 6L As shown, the first end 118A1 of the first optical isolation 118A on the first end 108A1 of the first grating coupler 108A is farther than the first end 118B1 of the second optical isolation 118B on the first end 108A1, and the second end 118B2 of the second optical isolation 118B is farther than the second end 118A2 of the first optical isolation 118A on the second end 108A2 of the first grating coupler 108A. The shapes of the first optical isolation 118A and the second optical isolation 118B are not limited to the exemplary embodiments described above. For example, the shapes shown in FIG6A to FIG6B are possible. Figure 6L Any combination of the shapes of the first optical isolation 118A or the second optical isolation 118B and / or based on Figures 6A to 6B Figure 6L Appropriate variations.

[0105] In some embodiments, the first optical protective structure 118 is or includes a non-transparent material, such as a metallic material including Cu, Ti, Al, Ag, Au, Cr, W, combinations thereof, or compounds such as TiN, TaN, WN, or combinations thereof. In some embodiments, the first optical protective structure 118 is or includes a dielectric material having a sufficient refractive index difference from the material of the cladding layer 110 (e.g., when the cladding layer 110 is SiO, the first optical protective structure 118 is SiN).

[0106] According to some implementation methods, in Figure 7 In this configuration, interconnect structure 120 is formed over device layer 102A, cladding layer 110, and contacts 116. Interconnect structure 120 includes a first dielectric layer 122, a second dielectric layer 124, and a third dielectric layer 126 (collectively referred to as dielectric layer 127), and a connection layer 128 formed in dielectric layer 127 to provide electrical interconnection. For example, interconnect structure 120 may electrically connect conductive vias 114, contacts 116, and / or overlying components (e.g., electronic chips 144) (see FIG. 9). Dielectric layer 127 may be, for example, an insulating or passivation layer, and may include one or more transparent dielectric materials, such as silicon oxide, silicon nitride, silicon oxynitride, low-k materials (e.g., dielectric constants below 3.5), or those described above for cladding layer 110. The third dielectric layer 126 may be the topmost dielectric layer of interconnect structure 120, also referred to as a bonding layer. In some embodiments, dielectric layer 127 is transparent to light of the same wavelength as cladding layer 110. Dielectric layer 127 can be formed using techniques similar to those described above for cladding layer 110 or using different techniques. Connector layer 128 may include conductive lines and vias and can be formed by a damascene process, such as single damascene, double damascene, etc. As shown in FIG7, connector layer 128 also includes a conductive plate 130 formed in the topmost layer (e.g., third dielectric layer 126) of dielectric layer 127. After forming conductive plate 130, a planarization process (e.g., CMP process, etc.) may be performed such that the surface of conductive plate 130 is substantially coplanar with the surface of third dielectric layer 126. Interconnect structure 120 may include more or fewer dielectric layers 127, connector layers 128, or conductive plates 130 than shown in FIG7.

[0107] It should be understood that the interconnect structure 120 may include any number of dielectric layers and metallization patterns. If more dielectric layers and metallization patterns are required, similar steps and processes as described above can be repeated. The metallization patterns may include conductive lines and conductive vias. Conductive vias can be formed during the formation of the metallization patterns by forming a seed layer of the metallization pattern and conductive material in the openings of the underlying dielectric layer. Therefore, conductive vias enable the conductive lines to interconnect and be electrically connected.

[0108] In some embodiments, certain regions of the interconnect structure 120 are substantially devoid of the interconnect layer 128, the conductive plate 130 (hereinafter referred to as the optical region), or any features for electrical transmission purposes, to allow the transmission of optical power or optical signals through the dielectric layer 127. For example, the transparent region may extend between the grating coupler 108 and the external photonic element 160 (see [link to documentation]). Figure 11 This allows optical power or optical signals to be coupled from waveguide 104 to and / or from external photonic element 160 to waveguide 104. In some cases, a thinner interconnect structure 120 can achieve more efficient optical coupling between grating coupler 108 and external photonic element 160.

[0109] In some embodiments, the interconnect structure 120 also includes a second optical protection structure 132 disposed in the first dielectric layer 122, a third optical protection structure 134 disposed in the second dielectric layer 124, and a fourth optical protection structure 136 disposed in the first dielectric layer 122. In some embodiments, the second optical protection structure 132, the third optical protection structure 134, and the fourth optical protection structure 136 each include a plurality of optical isolations. For example, the second optical protection structure 132 may include a first optical isolation 132A located above the first optical isolation 118A of the first optical protection structure 118 and a second optical isolation 132B located above the second optical isolation 118B of the first optical protection structure 118. The third optical protection structure 134 may include a first optical isolation 134A located above the first optical isolation 132A of the second optical protection structure 132 and a second optical isolation 134B located above the second optical isolation 132B of the second optical protection structure 132. The fourth optical protection structure 136 may include a first optical isolation 136A above the first optical isolation 134A of the third optical protection structure 134 and a second optical isolation 136B above the second optical isolation 134B of the third optical protection structure 134. Each of the second optical protection structure 132, the third optical protection structure 134, and the fourth optical protection structure 136 may have a pattern similar to or corresponding to the first optical protection structure 118, for example, as shown in Figures 6A to 6B. Figure 6L The shapes shown are as described. In some embodiments, the second optical protection structure 132, the third optical protection structure 134, and the fourth optical protection structure 136 have different dimensions. For example, the fourth optical protection structure 136 may be larger than the third optical protection structure 134, and the third optical protection structure 134 may be larger than the second optical protection structure 132. The second optical protection structure 132 is larger than the first optical protection structure 118.

[0110] In some embodiments, the second to fourth optical protective structures 132 to 136 are manufactured in the same process as forming the connecting layer 128. The second to fourth optical protective structures 132 to 136 may have the same material as the connecting layer 128. In some embodiments, the forming process of the second to fourth optical protective structures 132 to 136 differs from the process of forming the connecting layer 128, although some processes (e.g., planarization processes) may be shared. In such embodiments, the second to fourth optical protective structures 132 to 136 may have a different material than the connecting layer 128.

[0111] In some implementations, such as Figure 8A As shown, the first optical isolations 118A, 132A, 134A, and 136A of the first to fourth optical protection structures 118, 132, 134, and 136 gradually move the second grating coupler 108B from a lower level to a higher level. In some embodiments, the second optical isolations 118B, 132B, 134B, and 136B of the first to fourth optical protection structures 118, 132, 134, and 136 gradually move away from the first grating coupler 108A from a lower level to a higher level. In such embodiments, as... Figure 8B In the plan view shown, the first optical isolations 118A, 132A, 134A, and 136A of the first to fourth optical protection structures 118, 132, 134, and 136A can form a continuous structure and accommodate the first optical path 140A, which is guided to the first grating coupler 108A in a non-perpendicular direction. The second optical isolations 118B, 132B, 134B, and 136B of the first to fourth optical protection structures 118, 132, 134, and 136 can also form a continuous structure and accommodate the second optical path 140B, which is directed to the second grating coupler 108B in a non-perpendicular direction. The first optical path 140A and the second optical path 140B can be relatively far apart from the lower layer to the higher layer. This allows for more effective separation of the first and second optical paths 140A and 140B leading to the first grating coupler 108A and the second grating coupler 108B, thereby reducing optical interference between adjacent optical signals directed to the first grating coupler 108A and the second grating coupler 108B, respectively. The first optical isolation 118A, 132A, 134A and 136A and / or the first to fourth optical protection structures 118B, 132B, 134B and 136B of the first to fourth optical protection structures 118, 132, 134 and 136 not only... Figure 8B As shown, it moves gradually in all directions and can gradually move in any direction to collect light from the external photonic element 160.

[0112] In some embodiments, the materials of the second to fourth optical protective structures 132 to 136 are or include non-transparent materials, such as metallic materials including Cu, Ti, Al, Ag, Au, Cr, W, and combinations thereof, or compounds such as TiN, TaN, WN, and combinations thereof, or similar substances. In some embodiments, the second to fourth optical protective structures 132 to 136 are or include dielectric materials that have a sufficient refractive index difference from the material of the dielectric layer 127 (e.g., when the material of the dielectric layer 127 is SiN, the second to fourth optical protective structures 132 to 136 are SiN).

[0113] According to some implementation methods, in Figure 9 In this configuration, the electronic die 144 is bonded to the interconnect structure 120. The electronic die 144 may be, for example, a semiconductor device, die, or wafer that communicates with the photonic element 106 using electrical signals. Figure 9 A single electronic die 144 is shown, but in some embodiments, the photonic package 100 may include two or more electronic dies 144. In one embodiment, multiple electronic dies 144 may be incorporated into a single photonic package 100.

[0114] Electronic die 144 may include integrated circuits for interfacing with photonic elements, such as circuitry for controlling the operation of photonic element 106. For example, electronic die 144 may include a controller, driver, transimpedance amplifier, or a combination thereof. In some embodiments, electronic die 144 may also include a central processing unit (CPU). In some embodiments, electronic die 144 includes circuitry for processing electrical signals received from photonic element 106, such as circuitry for processing electrical signals received from a photodetector. In some embodiments, electronic die 144 may control the high-frequency signal transmission of photonic element 106 based on electrical signals (digital or analog) received from another device (e.g., from a processing chip). In some embodiments, electronic die 144 may act as part of an I / O interface between optical and electrical signals within a photonic system.

[0115] The electronic die 144 includes a die connector 146 disposed in a dielectric bonding layer 148. The die connector 146 may be, for example, a conductive plate, a conductive post, etc. The dielectric bonding layer 148 may have a material similar to the third dielectric layer 126. In some embodiments, the electronic die 144 is bonded to the interconnect structure 120 via dielectric-dielectric bonds and / or metal-metal bonds. In some embodiments, covalent bonds are formed between the dielectric bonding layer 148 and the third dielectric layer 126. During the bonding process, metal bonding may also occur between the die connector 146 of the electronic die 144 and the conductive plate 130 of the interconnect structure 120. Furthermore, by bonding the electronic die 144 to the interconnect structure 120 in this manner, the thickness of the resulting photonic package 100 can be reduced. And the optical coupling between the grating coupler 108 and the external photonic element 160 can be improved.

[0116] According to some implementation methods, in Figure 10 In this configuration, an insulating layer 150 is formed near the electronic die 144 and over the interconnect structure 120. The insulating layer 150 may comprise a transparent dielectric material, such as silicon oxide, silicon nitride, polymers, or combinations thereof. In some embodiments, the insulating layer 150 may be a material (e.g., silicon oxide) that is substantially transparent to light of a wavelength suitable for transmitting optical signals or optical power between the external photonic element 160 and the grating coupler 108.

[0117] The insulating layer 150 can be formed by a suitable deposition method, including CVD, PVD, or combinations thereof. In some embodiments, the insulating layer 150 is formed using HDP-CVD, FCVD, or combinations thereof. In some embodiments, the insulating layer 150 covers the electronic die 144 and fills the gaps between adjacent electronic dies 144 after deposition. Planarization processes can be performed, such as CMP processes, polishing processes, etc. In one embodiment, the top surface of the electronic die 144 is exposed from the insulating layer 150 and is coplanar with the top surface of the insulating layer 150. In some embodiments, the insulating layer 150 covers the top surface of the electronic die 144 and has a planarized top surface. In some embodiments, the combined thickness T of the cladding layer 110, dielectric layer 127, and insulating layer 150 above the grating coupler 108 is between about 10 μm and about 50 μm. In some embodiments, the thickness T can be less than about 30 μm.

[0118] exist Figure 11In some embodiments, a support substrate 156 is attached to an insulating layer 150. The support substrate 156 is a rigid structure attached to the structure to provide structural or mechanical stability. The use of the support substrate 156 can reduce warping or bending, thereby improving the performance of optical structures such as waveguide 104 or photonic element 106. The support substrate 156 may include one or more materials, such as silicon (e.g., silicon wafer, bulk silicon, etc.), silicon oxide, metal, organic core material, or other types of materials. An adhesive layer can be used to attach the support substrate 156 to the structure (e.g., to the insulating layer 150 and / or electronic die 144), or direct bonding or other suitable techniques can be used to attach the support substrate 156. In some embodiments, the thickness of the support substrate 156 may be between about 500 μm and about 700 μm. The lateral dimensions (e.g., length, width, and / or area) of the support substrate 156 may also be greater than, approximately the same as, or smaller than the substrate 102. In some embodiments, the support substrate 156 is attached in a later process step than shown during the fabrication of the photonic package 100. For some embodiments where a thinner form of the photonic package 100 is required, the support substrate 156 may be removed after the formation of the conductive connector 154 or in subsequent fabrication steps. In some embodiments, the support substrate 156 is not removed to reduce warping or bending of the photonic package 100.

[0119] An external photonic element 160 may be disposed above the support substrate 156 (or, if the support substrate 156 is absent, above the insulating layer 150). The external photonic element 160 (e.g., an optical fiber or lens) may serve as the optical input / output (I / O) of the photonic package 100. In some embodiments, a first grating coupler 108A may communicate with one of the external photonic elements 160 via a first optical path 140A, and a second grating coupler 108B may communicate with another external photonic element 160 via a second optical path 140B, wherein the light transmitted in the first optical path 140A and the second optical path 140B will not interfere with each other because the optical protection structure can effectively reduce or prevent optical interference. In some embodiments, the first optical path 140A or the second optical path 140B may have a length OL, which may be the thickness of the support substrate 156 plus a combined thickness T, or simply the combined thickness T (if the support substrate 156 is removed).

[0120] Still referencing Figure 11 According to some embodiments, the back side of the bulk substrate 102C is thinned to expose conductive vias 114, and a conductive plate 152 is formed. The bulk substrate 102C can be thinned by CMP processes, mechanical polishing, etc. Figure 11In some embodiments, a conductive plate 152 is formed on the exposed conductive via 114 and the bulk substrate 102C. The conductive plate 152 is electrically connected to the interconnect structure 120. The conductive plate 152 may be formed of a conductive material such as copper, aluminum, other metals or metal alloys, or combinations thereof. In some embodiments, after flipping the support substrate 156, a passivation layer such as silicon oxide or silicon nitride (not shown) may be formed over the bulk substrate 102C to laterally surround or partially cover the conductive plate 152.

[0121] A conductive connector 154 is formed on a conductive plate 152. The conductive connector 154 may be a ball grid array (BGA) connector, solder balls, metal pillars, controlled collapse die connection (C4) bumps, microbumps, bumps formed by electroless nickel-palladium immersion gold (ENEPIG) technology, etc. The conductive connector 154 may include conductive materials such as solder, copper, aluminum, gold, nickel, silver, palladium, tin, etc., or combinations thereof. In some embodiments, the conductive connector 154 is formed by first forming a layer of solder using common methods such as evaporation, electroplating, printing, solder transfer, ball placement, etc. Once a layer of solder is formed on the structure, reflow can be performed to shape the material into the desired bump shape. In another embodiment, the conductive connector 154 is a metal pillar (e.g., a copper pillar) formed via methods such as sputtering, printing, electroplating, electroless plating, CVD, etc. The metal pillar may be solder-free and have substantially vertical sidewalls. In some embodiments, a metal overlay (not shown) is formed over the conductive connector 154. The metallic coating may include nickel, tin, tin-lead, gold, silver, palladium, indium, nickel-palladium-gold, nickel-gold, or combinations thereof, and may be formed by an electroplating process.

[0122] In some embodiments, the photonic package 100 is integrated with other electrical and / or photonic components, other electrical and / or photonic chips, or other electrical and / or photonic packages to form a photonic system. For example, the photonic package 100 can then be mounted to an interposer, organic substrate, or PCB via a conductive connector 154.

[0123] By forming a first optical protection structure 118 in the cladding layer 110 of the photonic die 101 and / or forming second to fourth optical protection structures 132 to 136 in the interconnect structure 120, the optical path pointing to the grating coupler 108 (e.g., the first grating coupler 108A and the second grating coupler 108B) is protected by the optical protection structures. Therefore, even as the photonic package 100 continues to shrink and it becomes necessary to use grating couplers 108 closely arranged in a small space, the resulting optical interference problems can be reduced or resolved. In some embodiments, at least one of the first to fourth optical protection structures 118, 132 to 136 may be omitted depending on design or manufacturing capabilities or cost. For example, when the grating couplers 108 are too close together such that there is insufficient space between the first grating coupler 108A and the second grating coupler 108B to form the first optical protection structure 118, it may not be necessary to form the first optical protection structure 118. In such embodiments, the dimensions of the second to fourth optical protection structures 132 to 136 can be reduced to be substantially the same as or smaller than the size of the grating coupler 108, in order to achieve the intended purpose of reducing optical interference. In some embodiments, as described below, more optical protection structures can be added to further enhance the performance of the optical protection structures.

[0124] refer to Figure 12 In some embodiments, the photonic package 100 also includes at least one dummy die 164. In some embodiments, the dummy die 164 is encapsulated at least laterally by an insulating layer 150 to reduce the amount of insulating layer 150 and help improve thermal expansion coefficient (CTE) mismatch, thereby preventing warping of the photonic package 100. In some embodiments, the dummy die 164 may be bonded over the interconnect structure 120 before the insulating layer 150 is provided over the interconnect structure 120. For example, the electronic die 144 and the dummy die 164 may be picked up and placed (bonded) onto the interconnect structure 120 in the same step. Then, the insulating layer 150 is provided over the interconnect structure 120 to at least laterally encapsulate the electronic die 144 and the dummy die 164.

[0125] In some embodiments, the dummy die 164 includes a substrate 164A and a dielectric bonding layer 166 facing the interconnect structure 120 to allow the dummy die 164 to bond to the third dielectric layer 126 of the interconnect structure 120. In some embodiments, the dielectric bonding layer 166 includes a material similar to that described for dielectric layer 127, such as silicon oxide. A fifth optical protection structure 168 may be formed in the dielectric bonding layer 166, for example, by a damascene process. The fifth optical protection structure 168 may be disposed over the fourth optical protection structure 136. For example, the fifth optical protection structure 168 may include a first optical isolation 168A disposed over a first optical isolation 136A of the fourth optical protection structure 136 and a second optical isolation 168B disposed over a second optical isolation 136B of the fourth optical protection structure 136. In some embodiments, the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168 contact the first optical isolation 136A and the second optical isolation 136B of the fourth optical protection structure 136, respectively, thereby forming metal-metal bonds. The fifth optical protection structure 168 may overlap with the gap G in a planar view. The fifth optical protection structure 168 may also extend beyond the first end 108A1 and the second end 108A2 of the first grating coupler 108A and / or the first end 108B1 and the second end 108B2 of the second grating coupler 108B.

[0126] The first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168 can have the features shown in Figure 6A to 6B. Figure 6L The shape of the planar diagram shown. For example, the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168 may each have substantially the same shape as the first optical isolation 136A and the second optical isolation 136B of the fourth optical protection structure 136. In some embodiments, the dimensions of the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168 may be larger than the dimensions of the first optical isolation 136A and the second optical isolation 136B of the fourth optical protection structure 136. In such embodiments, the first to fifth optical protection structures 118, 132 to 136 and 168 may form a continuous structure with tapered sidewalls. In some embodiments, the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168 may be horizontally offset along the offset direction to the first optical isolation 136A and the second optical isolation 136B of the fourth optical protection structure 136, as shown in FIG8A and Figure 8B As shown. In some implementations, such as Figure 12As shown, the first optical isolation 136A and the second optical isolation 136B of the fourth optical protection structure 136 have a conical shape, and the first optical isolation 168A and the second optical isolation 168B of the fifth optical isolation structure also have a conical shape. In some embodiments, the fifth optical protection structure 168 is omitted, so that there are no properties (except impurities) in the dielectric bonding layer 166.

[0127] refer to Figure 13 According to some embodiments, the dummy die 164 further includes a sixth optical protection structure 170 disposed in the substrate 164A of the dummy die 164. The sixth optical protection structure 170 may include a first optical isolation 170A disposed above the first optical isolation 168A of the fifth optical protection structure 168, and a second optical isolation 170B disposed above the second optical isolation 168B of the fifth optical protection structure 168.

[0128] The sixth optical protection structure 170 may overlap with the gap G in the plan view. The sixth optical protection structure 170 may also extend above the first end 108A1 and the second end 108A2 of the first grating coupler 108A and / or the first end 108B1 and the second end 108B2 of the second grating coupler 108B. The first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170 may have the features shown in Figure 6A to... Figure 6L The planar shape is shown. For example, the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170 may each have substantially the same shape as the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168. In one embodiment, the dimensions of the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170 are larger than the dimensions of the first optical isolation 168A and the second optical isolation 168B of the fifth optical protection structure 168. In such an embodiment, the first to sixth optical protection structures 118, 132 to 136, 168 and 170 may form a continuous structure with tapered sidewalls. In some embodiments, the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170 may be horizontally offset from the first optical isolation 168A, and the second optical isolation 168B of the fifth optical protection structure 168 may be along the plane as shown. Figure 8A and Figure 8B The displacement direction is shown. In some embodiments, the sixth optical protection structure 170 is a substrate through-hole (TSV) and can be formed by any suitable method for forming a TSV. For example... Figure 13As shown, the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170 have vertical sidewalls. In some embodiments, the sixth optical protection structure 170 has inverted conical sidewalls. In some embodiments, the sixth optical protection structure 170 is omitted, so that there are no features (except impurities) in the substrate 164A.

[0129] refer to Figure 14 According to some embodiments, the support substrate 156 further includes a seventh optical protection structure 174 disposed in the support substrate 156. The seventh optical protection structure 174 may include a first optical isolation 174A disposed above the first optical isolation 170A of the sixth optical protection structure 170 (or, if the sixth optical protection structure 170 does not exist, it is disposed above the first optical isolation of another optical protection structure), and a second optical isolation 174B disposed above the second optical isolation 170B of the sixth optical protection structure 170 (or, if the sixth optical protection structure 170 does not exist, it is disposed above the second optical isolation of another optical protection structure).

[0130] The seventh optical protection structure 174 may overlap with the gap G in the plan view. The seventh optical protection structure 174 may also extend above the first end 108A1 and the second end 108A2 of the first grating coupler 108A, and / or the first end 108B1 and the second end 108B2 of the second grating coupler 108B. The first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 may have the features shown in Figure 6A to... Figure 6L The shape of the planar diagram shown. For example, the first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 may have substantially the same shape as the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170. In some embodiments, the dimensions of the first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 may be larger than the dimensions of the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170. In such embodiments, the first to seventh optical protection structures 118, 132 to 136, 168, 170 and 174 may form a continuous structure with tapered sidewalls. In some embodiments, the first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 may be horizontally offset along the offset direction to the first optical isolation 170A and the second optical isolation 170B of the sixth optical protection structure 170, as shown in FIG8A and Figure 8BAs shown. In some embodiments, the seventh optical protection structure 174 is a substrate through-hole (TSV) that completely penetrates the support substrate 156, and can be formed by any method suitable for forming a TSV. A through-hole that only partially penetrates the support substrate 156 can also be used for the seventh optical protection structure 174. For example... Figure 14 As shown, the first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 have vertical sidewalls. However, the first optical isolation 174A and the second optical isolation 174B of the seventh optical protection structure 174 may each have a conical or inverted conical shape in cross-sectional view. In some embodiments, the seventh optical protection structure 174 is omitted, so that there are no features (except impurities) in the support substrate 156.

[0131] In some embodiments, any one of the first to seventh optical protection structures 118, 132 to 136, 168, 170, and 174 may be omitted depending on design, manufacturing capability, and / or manufacturing cost requirements. Longer lengths (whether continuous or discontinuous) of the first to seventh optical protection structures 118, 132 to 136, 168, 170, and 174 can result in better performance in reducing or preventing optical interference. In some embodiments, more than 90% of the optical path (e.g., more than 90% of the length OL or thickness T) is laterally surrounded by structures formed by any combination of the first to seventh optical protection structures 118, 132 to 136, 168, 170, and 174 to achieve optimal performance in reducing optical interference. In some embodiments, more than 50% of the optical path (e.g., more than 90% of the length OL or thickness T) is laterally surrounded by structures formed by any combination of the first to seventh optical protection structures 118, 132 to 136, 168, 170, and 174 to balance performance with manufacturing complexity and cost. In some embodiments, about 10% to about 30% of the optical path (e.g., more than 90% of the length OL or the thickness T) is laterally surrounded by a structure formed by any combination of the first to seventh optical protection structures 118, 132 to 136, 168, 170, 174, to reduce manufacturing complexity and cost to a certain extent, while still having sufficient performance to reduce optical interference.

[0132] This disclosure provides a photonic package including optical and electrical components and a method for forming the same. Specifically, the photonic package may include a grating coupler as an interface for transmitting or receiving optical signals from an external photonic device. This invention also provides an optical protection structure that can be disposed around the optical path leading to the grating coupler, such as between grating couplers, in the interconnection structure of photonic chips, in dummy chips, in a support substrate, or in combinations thereof, which can effectively reduce interference between optical signals. Therefore, the photonic package may include a higher density of grating couplers while reducing optical signal transmission noise.

[0133] One embodiment is a package including a photonic die, the photonic die comprising: a waveguide disposed in a cladding layer; a first grating coupler and a second grating coupler disposed in the cladding layer, wherein a gap exists between the first grating coupler and the second grating coupler in a first direction, wherein the first grating coupler has a first end (and a second end opposite to the first end in a second direction perpendicular to the first direction); a first optical protection structure passing through the cladding layer and disposed in the gap between the first grating coupler and the second grating coupler, wherein the first optical protection structure extends beyond the first end and the second end of the first grating coupler in a second direction, and an interconnect structure above the cladding layer; wherein the interconnect structure includes a connection layer disposed in a first dielectric layer and a second dielectric layer; an electronic die including circuitry electrically coupled to the interconnect structure; and an insulating layer laterally surrounding the electronic die. In one embodiment, the package further includes a second optical protection structure disposed in the first dielectric layer and a third optical protection structure disposed in the second dielectric layer. The third optical protection structure is disposed above the second optical protection structure, wherein the second and third optical protection structures overlap with the first optical protection structure and the gap between the first and second grating couplers in a plan view. In one embodiment, the package further includes a dummy die disposed in the insulating layer, wherein the dummy die includes a dielectric bonding layer bonded to the second dielectric layer and a fourth optical protection structure disposed in the dielectric bonding layer, wherein the fourth optical protection structure extends beyond the first and second ends of the first grating coupler in a second direction and overlaps with the gap between the first and second grating couplers in a plan view. In one embodiment, the package further includes a substrate attached to the insulating layer. In one embodiment, the substrate includes a fifth optical protection structure extending beyond the first and second ends of the first grating coupler in a second direction and overlapping with the gap between the first and second grating couplers in a plan view. In one embodiment, the first optical protection structure includes a first optical isolation and a second optical isolation, wherein the total length of the first and second optical isolation in the second direction is at least twice the length of the first grating coupler in the second direction. In one embodiment, the first optical isolation has a first shape that surrounds the first grating coupler in a plan view, and the second optical isolation has a second shape that surrounds the second grating coupler in a plan view.

[0134] Another embodiment is a package comprising: a photonic die, including: a waveguide disposed in a cladding; a first grating coupler and a second grating coupler disposed in the cladding, wherein a gap exists between the first grating coupler and the second grating coupler in a first direction, wherein the first grating coupler has a first end and a second end opposite to the first end in a second direction perpendicular to the first direction; and an interconnect structure located above the cladding, the interconnect structure including: a first dielectric layer; a second dielectric layer above the first dielectric layer; a connection layer disposed in the first dielectric layer and the second dielectric layer; a first optical protection structure disposed in the first dielectric layer, wherein the first optical protection structure is located between the first grating coupler and the second grating coupler and extends in a second direction in a plan view beyond the first end and the second end of the first grating coupler; and a second optical protection structure disposed in the second dielectric layer and overlapping the first optical protection structure in a plan view; an electronic die disposed above the interconnect structure and electrically coupled to the interconnect structure; and an insulating layer laterally surrounding the electronic die. In one embodiment, the second optical protection structure includes a first optical isolation and a second optical isolation extending in a gap, wherein the first optical isolation extends toward the first grating coupler in a portion extending beyond a first end of the first grating coupler, and the second optical isolation extends toward the second grating coupler in a portion extending beyond a second end of the first grating coupler. In one embodiment, the first and second optical isolations of the first optical protection structure have different shapes in a plan view. In one embodiment, the second optical protection structure includes a third optical isolation on the first optical isolation of the first optical protection structure and a fourth optical isolation on the second optical isolation of the first optical protection structure, wherein the third optical isolation is further from the second grating coupler in the horizontal direction than the first optical isolation, and the fourth optical isolation is further from the first grating coupler in the horizontal direction than the second optical isolation. In one embodiment, the package further includes a third optical protection structure disposed in the cladding and located between the first and second grating couplers, wherein the first, second, and third optical protection structures form a continuous structure. In one embodiment, the size of the second optical protection structure is larger than the size of the first optical protection structure. In one embodiment, the package further includes a dummy die disposed in an insulating layer, wherein the dummy die includes a dielectric bonding layer bonded to a second dielectric layer, a substrate, and a third optical protection structure disposed in the substrate, wherein the third optical protection structure extends beyond the first end and the second end of the first grating coupler in a second direction and overlaps with the gap between the first grating coupler and the second grating coupler in a plan view.In one embodiment, the package further includes a support substrate attached to an insulating layer, wherein the support substrate includes a fourth optical protection structure disposed therein, wherein the fourth optical protection structure extends beyond the first and second ends of the first grating coupler in a second direction and overlaps with the gap between the first and second grating couplers in a plan view, wherein the fourth optical protection structure has a through-hole.

[0135] A further embodiment is a method of forming a package. This method includes patterning a layer to form a waveguide, a first grating coupler, and a second grating coupler, wherein the first and second grating couplers have a gap in a first direction, wherein the first grating coupler has a first end and a second end opposite to the first end in a second direction perpendicular to the first direction; forming a cladding layer over the waveguide, the first grating coupler, and the second grating coupler; forming a first optical protection structure between the first and second grating couplers, wherein the first optical protection structure extends beyond the first and second ends of the first grating coupler in the second direction; forming an interconnect structure on the cladding layer, wherein the interconnect structure includes a connection layer disposed in a dielectric layer; bonding an electronic die to the interconnect structure; and forming an insulating layer laterally surrounding the electronic die. In one embodiment, the method includes forming a second optical protection structure in the dielectric layer during the formation of the connection layer, wherein the second optical protection structure overlaps in a planar view with the first optical protection structure and the gap between the first and second grating couplers. In one embodiment, the second optical structure in the dielectric layer is formed after the formation of the connection layer. In one embodiment, the first optical protection structure includes a first optical isolation and a second optical isolation extending in a gap, wherein the first optical isolation extends toward a first grating coupler in a portion beyond a first end of the first optical isolation. The second optical isolation extends toward a second grating coupler in a portion beyond a second end of the first grating coupler, wherein the first and second optical isolations are formed in the same process. In one embodiment, the method further includes attaching a pad to an insulating layer, and the method further includes forming a third optical protection structure in the substrate after attaching the substrate to the insulating layer, wherein the third optical protection structure overlaps with the gap between the first and second grating couplers in a plan view.

[0136] The foregoing outlines the features of many embodiments to enable those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis to design or modify other processes and structures to achieve the same objectives and / or advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure.

Claims

1. A package, characterized in that, include: A single photonic crystal grain includes: A waveguide is set in a cladding layer; A first grating coupler and a second grating coupler are disposed in the cladding layer, wherein the first grating coupler and the second grating coupler have a gap in a first direction, wherein the first grating coupler has a first end and a second end, and the second end is opposite to the first end in a second direction perpendicular to the first direction; A first optical protection structure extends through the cladding layer and the gap between the first grating coupler and the second grating coupler, wherein the first optical protection structure extends over the first end and the second end of the first grating coupler in the second direction; and An interconnect structure is provided on the covering layer, wherein the interconnect structure includes a connection layer disposed in a first dielectric layer and a second dielectric layer; An electronic die, comprising a plurality of circuits electrically coupled to the interconnect layer of the interconnect structure; and An insulating layer is laterally surrounding the electronic grain.

2. The package as described in claim 1, characterized in that, It also includes a second optical protection structure disposed in the first dielectric layer, and a third optical protection structure disposed in the second dielectric layer, wherein the third optical protection structure is disposed on top of the second optical protection structure, and wherein the second optical protection structure and the third optical protection structure overlap the gap between the first optical protection structure and the first grating coupler and the second grating coupler in a planar viewing angle.

3. The package as described in claim 1, characterized in that, It also includes a dummy die in the insulating layer, wherein the dummy die includes a dielectric bonding layer bonded to the second dielectric layer, and a fourth optical protection structure disposed in the dielectric bonding layer, wherein the fourth optical protection structure extends in the second direction over the first end and the second end of the first grating coupler and overlaps the gap between the first optical protection structure and the first grating coupler and the second grating coupler in a planar viewing angle.

4. The package as described in claim 1, characterized in that, It also includes a substrate attached to the insulating layer.

5. The package as described in claim 4, characterized in that, The substrate includes a fifth optical protection structure that extends over the first end and the second end of the first grating coupler in the second direction and overlaps the gap between the first grating coupler and the second grating coupler in a planar view.

6. The package as described in claim 1, characterized in that, The first optical protection structure includes a first optical isolation and a second optical isolation, wherein the total length of the first optical isolation and the second optical isolation in the second direction is at least twice the total length of the first grating coupler in the second direction.

7. A package, characterized in that, include: A single photonic crystal grain includes: A waveguide is set within a cladding layer; A first grating coupler and a second grating coupler are disposed in the cladding layer, wherein a gap exists between the first grating coupler and the second grating coupler in a first direction, wherein the first grating coupler has a first end and a second end, the second end being opposite to the first end in a second direction perpendicular to the first direction; and An interconnect structure, on top of the covering layer, includes: First dielectric layer; A second dielectric layer is disposed on top of the first dielectric layer; A connection layer is disposed in a first dielectric layer and a second dielectric layer; A first optical protection structure is disposed in the first dielectric layer, wherein the first optical protection structure extends between the first grating coupler and the second grating coupler and over the first end and the second end of the first grating coupler in the second direction in a planar viewing angle; and A second optical protection structure is disposed in the second dielectric layer and overlaps the first optical protection structure in the planar view; An electronic die is disposed on the interconnect structure and electrically coupled to the connection layer of the interconnect structure; and An insulating layer is laterally surrounding the electronic grain.

8. The package as described in claim 7, characterized in that, The second optical protection structure includes a first optical isolation and a second optical isolation extending in the gap, wherein the first optical isolation extends toward the first grating coupler in a portion beyond the first end of the first grating coupler, and the second optical isolation extends toward the second grating coupler in a portion beyond the second end of the first grating coupler.

9. The package as described in claim 7, characterized in that, The second optical protection structure has a larger size than the first optical protection structure.

10. A package, characterized in that, include: A single photonic crystal grain includes: A waveguide is set within a cladding layer; A first grating coupler and a second grating coupler are disposed in the cladding layer, wherein the first grating coupler and the second grating coupler have a gap in a first direction, wherein the first grating coupler has a first end and a second end, and the second end is opposite to the first end in a second direction perpendicular to the first direction; A first optical protection structure extends through the cladding layer and the gap between the first grating coupler and the second grating coupler, wherein the first optical protection structure extends over the first end and the second end of the first grating coupler in the second direction; and An interconnect structure is provided on the covering layer, wherein the interconnect structure includes a connection layer disposed in a first dielectric layer and a second dielectric layer; An electronic die includes multiple circuits electrically coupled to the interconnect layer of the interconnect structure; A second optical protection structure is disposed in the first dielectric layer; and A third optical protection structure is disposed in the second dielectric layer, wherein the third optical protection structure is disposed on the second optical protection structure, and in a planar view, the second optical protection structure and the third optical protection structure overlap the gap between the first optical protection structure and the first grating coupler and the second grating coupler.

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