Packaging structure and forming method thereof

Abstract

The invention discloses a packaging structure and a forming method thereof, and the structure comprises a photon chip which is provided with an optical port; the at least one functional chip is arranged on the top surface of the photon chip, and the functional chip is electrically connected with the photon chip; the light path steering element is arranged on a light outgoing path or a light incoming path of the light port and is configured to change the propagation direction of a light signal emitted from the light port or guided into the light port; and the light-transmitting cover covers the light port and the light path steering element, the height of the light-transmitting cover is lower than that of the functional chip, and the light signal of which the propagation direction is changed by the light path steering element is led out or led in through at least one light-transmitting side surface of the light-transmitting cover. Therefore, the leading-in or leading-out of an optical signal is transferred from the top surface to the side surface of the packaging structure, so that the light-transmitting cover and the optical path steering element are protected during other processes such as a wafer thinning process and the like, and the risk that the light-transmitting cover and the optical path steering element are damaged or broken is reduced. Therefore, the reliability of the packaging structure and the transmission quality of optical signals in the packaging structure are improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of semiconductor manufacturing, and in particular to a packaging structure and a forming method thereof. BACKGROUND

[0002] In the field of optoelectronic packaging, with the increasing requirements of system on bandwidth, power consumption and size, high-density three-dimensional integration of photonic chips and electronic functional chips at the packaging level has become an important development direction. In such integrated packaging, the optical signals generated by the photonic chips need to be optically interconnected with external optical fibers or other optical waveguide devices through the packaging body, which involves the design, guidance and external coupling of the optical path inside the packaging. The transmission characteristics of optical signals require that their paths have good optical interfaces, accurate alignment and controllable propagation direction.

[0003] At the same time, the packaging structure not only needs to accommodate and interconnect multiple chips, but also needs to provide a reliable transmission path for electrical signals and design an effective dissipation path for the heat generated during device operation. Therefore, an optoelectronic packaging structure usually needs to cooperatively realize multiple functions such as optical management, electrical interconnection and thermal management in the same limited space. How to design the architecture of the space and materials inside the packaging body to simultaneously optimize the transmission efficiency and reliability of multiple physical signals such as light, electricity and heat is one of the concerns of the development of the field.

[0004] At present, the reliability of the packaging structure and the transmission quality of optical signals in the packaging structure still need to be improved. SUMMARY

[0005] The problem solved by embodiments of the present application is to provide a packaging structure and a forming method thereof, which improves the reliability of the packaging structure and the transmission quality of optical signals in the packaging structure.

[0006] To solve the above problems, the present disclosure provides a packaging structure, comprising: a photonic chip having an optical port; at least one functional chip disposed on the top surface of the photonic chip, and the functional chip is electrically connected with the photonic chip; an optical path turning element disposed on the light-out or light-in path of the optical port and configured to change the propagation direction of the optical signal emitted from or introduced into the optical port; a light-transmitting cover covering the optical port and the optical path turning element, the height of the light-transmitting cover is lower than the height of the functional chip, and the optical signal with changed propagation direction is guided out or introduced through at least one light-transmitting side surface of the light-transmitting cover.

[0007] Optionally, the photonic chip has a front surface and a back surface opposite to the front surface; the optical port is located on the front surface of the photonic chip; the light path turning element and the light-transmissive cover are both located above the front surface of the photonic chip; the packaging structure further comprises a plastic encapsulation layer located above the front surface of the photonic chip exposed by the functional chip, the light path turning element and the light-transmissive cover, and the plastic encapsulation layer covers the sidewall of the functional chip, the sidewall and the top of the light path turning element, and the sidewall and the top of the light-transmissive cover, and the plastic encapsulation layer exposes the light-transmissive side surface of the light-transmissive cover; or, the optical port is located on the back surface of the photonic chip; the light path turning element and the light-transmissive cover are both located below the back surface of the photonic chip; the packaging structure further comprises a plastic encapsulation layer located above the front surface of the photonic chip exposed by the functional chip, and the plastic encapsulation layer covers the sidewall of the functional chip.

[0008] Optionally, the material of the plastic encapsulation layer comprises plastic encapsulation material.

[0009] Optionally, the light path turning element comprises one or both of a prism and a diffraction grating.

[0010] Optionally, the light path turning element has a reflecting surface arranged at a first acute angle, and the first acute angle comprises an included angle between the surface of the photonic chip and the light path turning element; the light-transmissive cover covers the reflecting surface.

[0011] Optionally, the first acute angle is between 30 degrees and 60 degrees.

[0012] Optionally, the optical port comprises a grating coupler.

[0013] Optionally, the material of the light-transmissive cover comprises one or more of glass, quartz and optical polymer.

[0014] Optionally, the packaging structure further comprises a transparent adhesive layer arranged on the surface of the photonic chip, and the light-transmissive cover is fixed on the photonic chip through the transparent adhesive layer.

[0015] Optionally, the packaging structure further comprises a first conductive bump arranged between the functional chip and the photonic chip, and the functional chip is electrically connected to the photonic chip through the first conductive bump.

[0016] Optionally, the packaging structure further comprises an underfill layer located on the photonic chip and covering the sidewall of the first conductive bump and the functional chip.

[0017] Optionally, the material of the underfill layer comprises epoxy resin.

[0018] Optionally, the photonic chip has a front surface and a back surface opposite to the front surface; the functional chip is arranged on the front surface of the photonic chip; the packaging structure further comprises a second conductive bump located on the back surface of the photonic chip, and the second conductive bump is electrically connected to the back surface of the photonic chip.

[0019] Optionally, the packaging structure further comprises a substrate, and the photonic chip, the functional chip, the light path turning element, and the light-transmitting cover constitute a packaging body arranged on the substrate, and the second conductive bump is electrically connected to the substrate.

[0020] Optionally, the substrate comprises a printed circuit board or a circuit carrier board.

[0021] Optionally, the functional chip comprises one or more of an ASIC chip, an HBM chip, a CPU chip, a GPU chip, and an FPGA chip.

[0022] Correspondingly, the embodiment of the present application further provides a forming method of the packaging structure, comprising: providing a photonic chip, the photonic chip having an optical port; arranging at least one functional chip on a top surface of the photonic chip, and the functional chip being electrically connected to the photonic chip; arranging a light path turning element on an out-light or in-light path of the optical port of the photonic chip, the light path turning element being configured to change a propagation direction of a light signal emitted from or introduced into the optical port; arranging a light-transmitting cover on a surface of the photonic chip, the light-transmitting cover covering the optical port and the light path turning element, a height of the light-transmitting cover being lower than a height of the functional chip, and the light signal with the changed propagation direction being guided out or introduced via at least one light-transmitting side surface of the light-transmitting cover.

[0023] Optionally, in the step of providing the photonic chip, the photonic chip comprises a front surface and a back surface opposite to the front surface, and the optical port is located on the front surface of the photonic chip; in the step of disposing the optical path turning element and the light-transmitting cover, the optical path turning element and the light-transmitting cover are both located above the front surface of the photonic chip; after the optical path turning element and the light-transmitting cover are disposed, the forming method further comprises: forming a plastic sealing layer above the front surface of the photonic chip exposed by the functional chip, the optical path turning element and the light-transmitting cover, the plastic sealing layer covering the sidewall of the functional chip, the sidewall and the top of the optical path turning element, and the sidewall and the top of the light-transmitting cover, and the plastic sealing layer exposing the light-transmitting side surface of the light-transmitting cover; or, in the step of providing the photonic chip, the photonic chip comprises a front surface and a back surface opposite to the front surface, and the optical port is located on the back surface of the photonic chip; in the step of disposing the optical path turning element and the light-transmitting cover, the optical path turning element and the light-transmitting cover are both located below the back surface of the photonic chip; after the optical path turning element and the light-transmitting cover are disposed, the forming method further comprises: forming a plastic sealing layer above the front surface of the photonic chip exposed by the functional chip, the plastic sealing layer covering the sidewall of the functional chip.

[0024] Optionally, the material of the plastic sealing layer comprises plastic sealing material.

[0025] Optionally, the optical path turning element comprises one or both of a prism and a diffraction grating.

[0026] Optionally, the optical path turning element has a reflecting surface arranged at a first acute angle, and the first acute angle comprises an included angle between a surface of the photonic chip and the optical path turning element; the light-transmitting cover covers the reflecting surface.

[0027] Optionally, the first acute angle is between 30 degrees and 60 degrees.

[0028] Optionally, the optical port comprises a grating coupler.

[0029] Optionally, the material of the light-transmitting cover comprises one or more of glass, quartz and optical polymer.

[0030] Optionally, the step of disposing the light-transmitting cover on the surface of the photonic chip comprises: disposing a transparent adhesive layer on the surface of the photonic chip, disposing the light-transmitting layer on the transparent adhesive layer, and fixing the light-transmitting cover on the photonic chip through the transparent adhesive layer.

[0031] Optionally, in the step of disposing at least one functional chip on the top surface of the photonic chip, a surface of the functional chip is further formed with a first conductive bump, and the functional chip is electrically connected to the photonic chip through the first conductive bump.

[0032] Optionally, after the functional chip is disposed, before the light path turning element and the light-transmitting cover are disposed, the method further comprises: forming a bottom filling layer on the photonic chip, the bottom filling layer covering the first conductive bump and a sidewall of the functional chip.

[0033] Optionally, a material of the bottom filling layer comprises epoxy resin.

[0034] Optionally, in the step of providing the photonic chip, the photonic chip has a front surface and a back surface opposite to the front surface, the back surface of the photonic chip is formed with a second conductive bump, and the second conductive bump is electrically connected to the back surface of the photonic chip.

[0035] Optionally, the forming method further comprises: providing a substrate; and disposing the package composed of the photonic chip, the functional chip, the light path turning element, and the light-transmitting cover on the substrate, and the second conductive bump is electrically connected to the substrate.

[0036] Optionally, the substrate comprises a printed circuit board or a circuit carrier board.

[0037] Optionally, the functional chip comprises one or more of an ASIC chip, an HBM chip, a CPU chip, a GPU chip, and an FPGA chip.

[0038] Compared with the prior art, the technical scheme of the embodiment of the present application has the following advantages: The package structure provided by the embodiment of the present application is disposed on a light path of a light outlet or a light inlet of the optical port, changes a propagation direction of an optical signal emitted from the optical port or introduced into the optical port, and guides the optical signal to a light-transmitting side of the light-transmitting cover with a lower height than the functional chip to be emitted or introduced, so that the emission or introduction of the optical signal is transferred from a top surface of the package structure to a side surface, thereby protecting the light-transmitting cover and the light path turning element during a wafer thinning process and other processes, reducing a risk of damage or breakage of the light-transmitting cover and the light path turning element, and improving reliability of the package structure and transmission quality of the optical signal in the package structure.

[0039] The method for forming a packaging structure provided in this invention involves setting an optical path steering element on the light-emitting or light-incoming path of the optical port of the photonic chip. The optical path steering element is configured to change the propagation direction of the optical signal emitted from or introduced into the optical port. A light-transmitting cover is set on the surface of the photonic chip, covering the optical port and the optical path steering element. The height of the light-transmitting cover is lower than the height of the functional chip. The optical signal whose propagation direction is changed by the optical path steering element is exported or introduced through at least one light-transmitting side of the light-transmitting cover, so that the introduction or export of the optical signal is transferred from the top surface of the packaging structure to the side surface. This protects the light-transmitting cover and the optical path steering element during wafer thinning and other processes, reducing the risk of damage or breakage to the light-transmitting cover and the optical path steering element, thereby improving the reliability of the packaging structure and the transmission quality of the optical signal in the packaging structure. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the first type of packaging structure corresponding to an embodiment of the present invention; Figure 2 This is a schematic diagram of the second structure corresponding to the packaging structure of this invention embodiment; Figure 3 This is a flowchart of the steps corresponding to the packaging structure formation method of this invention embodiment; Figures 4 to 9 This is a schematic diagram of the structure corresponding to each step in the first embodiment of the method for forming the packaging structure according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure corresponding to each step in the second embodiment of the method for forming the packaging structure according to an embodiment of the present invention. Detailed Implementation

[0041] Currently, the reliability of the packaging structure and the transmission quality of optical signals within the packaging structure still need to be improved.

[0042] Specifically, the packaging structure includes the photonic chip with an optical port and at least one functional chip disposed on its top surface. A light-transmitting cover is directly covered on the optical port. The optical signal is exported or imported through the top surface of the light-transmitting cover in a direction perpendicular to the surface of the photonic chip. The height of the light-transmitting cover is usually equivalent to the height of the functional chip. The sidewalls of the functional chip and the light-transmitting cover are covered by the molding layer.

[0043] Research has revealed that because the optical port is directly covered by a light-transmitting cover, the optical signal is exported or imported through the top surface of the light-transmitting cover in a direction perpendicular to the surface of the photonic chip. Furthermore, the height of the light-transmitting cover is usually comparable to the height of the functional chip. The top surface of the light-transmitting cover is continuously exposed and directly bears process stress during critical processes such as wafer thinning, dicing, and molding after chip stacking. This makes it extremely prone to cracking or scratches, leading to damage to the optical path and a decrease in yield. Consequently, it affects the reliability of the packaging structure and the transmission quality of the optical signal within the packaging structure.

[0044] To address the aforementioned technical problems, this disclosure provides a packaging structure comprising: a photonic chip having an optical port; at least one functional chip disposed on the top surface of the photonic chip and electrically connected to the photonic chip; an optical path steering element disposed on the light-emitting or light-incoming path of the optical port and configured to change the propagation direction of an optical signal emitted from or introduced into the optical port; and a light-transmitting cover covering the optical port and the optical path steering element, wherein the height of the light-transmitting cover is lower than the height of the functional chip, and the optical signal whose propagation direction is changed by the optical path steering element is exported or introduced via at least one light-transmitting side of the light-transmitting cover.

[0045] The packaging structure provided in this invention includes an optical path steering element disposed on the path of light exiting or entering the optical port. This element changes the propagation direction of the optical signal emitted from or introduced into the optical port and guides it to the light-transmitting side of the light-transmitting cover, which is lower than the functional chip, for export or import. This transfers the import or export of the optical signal from the top surface of the packaging structure to the side surface, thereby protecting the light-transmitting cover and the optical path steering element during wafer thinning and other processes. This reduces the risk of damage or breakage to the light-transmitting cover and the optical path steering element, thereby improving the reliability of the packaging structure and the transmission quality of the optical signal within the packaging structure.

[0046] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0047] Figure 1 This shows a schematic diagram of the first type of packaging structure in an embodiment of the present invention; Figure 2 A schematic diagram of the second structure corresponding to the packaging structure in an embodiment of the present invention is shown.

[0048] The packaging structure includes: a photonic chip 102 having an optical port 150; at least one functional chip 110 disposed on the top surface of the photonic chip 102 and electrically connected to the photonic chip 102; an optical path steering element 122 disposed on the light output or input path of the optical port 150 and configured to change the propagation direction of an optical signal emitted from or introduced into the optical port 150; and a light-transmitting cover 140 covering the optical port 150 and the optical path steering element 122, the height of the light-transmitting cover 140 being lower than the height of the functional chip 110, and the optical signal whose propagation direction is changed by the optical path steering element 122 being exported or imported via at least one light-transmitting side 141 of the light-transmitting cover 140.

[0049] Specifically, the optical path steering element 122, disposed on the path of light output or input of the optical port 150, changes the propagation direction of the light signal emitted from or introduced into the optical port 150 and guides it to the light-transmitting side 141 of the light-transmitting cover 140, which is lower than the functional chip 110, for export or import. This transfers the import or export of the light signal from the top surface of the package structure to the side surface, thereby protecting the light-transmitting cover 140 and the optical path steering element 122 during wafer thinning and other processes, reducing the risk of damage or breakage to the light-transmitting cover 140 and the optical path steering element 122, thereby improving the reliability of the package structure and the transmission quality of the light signal in the package structure.

[0050] It should be noted that the photonic chip 102, as the core device for realizing photoelectric signal conversion or optical signal processing, is used to provide optical signal generation, modulation, reception or routing functions for the entire packaging structure.

[0051] Specifically, the optical port 150 provides a channel for optical signals to enter or exit the internal optical waveguide of the photonic chip 102.

[0052] In this embodiment, the optical port 150 includes a grating coupler.

[0053] It should be noted that the optical port 150 is a grating coupler, which can efficiently couple the optical signal transmitted in the waveguide of the photonic chip 102 along the direction parallel to the surface of the photonic chip 102 into an optical signal propagating outward along the direction perpendicular to the chip surface, or couple externally incident optical signals into the chip waveguide using the principle of diffraction.

[0054] In this embodiment, the photonic chip 102 has a front side 181 and a back side 182 opposite to the front side 181.

[0055] In this embodiment, the optical port 150 is located on the front side 181 of the photonic chip 102.

[0056] Specifically, by placing the optical port 150 on the front side 181 of the photonic chip 102, it can be monolithically integrated with other electronic components (such as waveguides) placed on the front side 181 to achieve a more compact and lower loss optical path interconnection. At the same time, it is convenient to place the optical path steering element 122 and the light-transmitting cover 140 on the front side 181 of the photonic chip 102.

[0057] It should be noted that the functional chip 110 is used to provide the necessary control, drive, signal processing, data storage or computing support for the photonic chip 102, such as driving the photonic modulator, processing the signals received by the photodetector, or providing coprocessing capabilities for photonic computing, thereby realizing the complex system functions of optoelectronic collaboration.

[0058] In this embodiment, the functional chip 110 is disposed on the front side 181 of the photonic chip 102.

[0059] The specific type of the functional chip 110 can be selected according to actual needs. In this embodiment, the functional chip 110 may include one or more of the following: ASIC (Application-Specific Integrated Circuit) chip, HBM (High Bandwidth Memory) chip, CPU (Central Processing Unit) chip, GPU (Graphics Processing Unit) chip, and FPGA (Field-Programmable Gate Array) chip.

[0060] Specifically, the optical path steering element 122 is used to receive the optical signal emitted from the optical port 150 of the photonic chip 102 and propagating along a first direction (e.g., vertical direction), and change its propagation direction to a second direction (e.g., horizontal direction) different from the first direction through reflection or diffraction, and finally guide the optical signal to the light-transmitting side 141 of the preset light-transmitting cover 140; or, in reverse, it redirects the optical signal introduced from the light-transmitting side 141 and propagating along the second direction (e.g., vertical direction) and couples it into the optical port 150.

[0061] In this embodiment, the optical path steering element 122 is located above the front surface 181 of the photonic chip 102.

[0062] In this embodiment, the optical path steering element 122 includes one or both of a prism and a diffraction grating.

[0063] It should be noted that prisms can achieve low-loss optical path deflection by utilizing the principle of total internal reflection, while diffraction gratings can achieve optical path deflection by utilizing their micro-nano structures. Both are mature and reliable optical components that are easy to integrate with packaging processes.

[0064] In this embodiment, the optical path steering element 122 has a reflective surface set at a first acute angle, and the first acute angle includes the angle between the surface of the photonic chip 102 and the optical path steering element 122.

[0065] Specifically, by setting the reflective surface at a first acute angle, the transmission direction of the vertically incident light signal can be changed to horizontal emission.

[0066] It should be noted that the first acute angle should not be too large or too small. If the first acute angle is too large, the incident angle of the incident light signal on the reflecting surface may deviate from the optimal reflection conditions, resulting in a decrease in the light signal reflection efficiency and possible transmission loss of some light signals. Furthermore, an excessively large angle may require the light-transmitting cover 140 to occupy more space in the vertical direction, which is detrimental to the miniaturization of the package. If the first acute angle is too small, the angle between the propagation path of the redirected light signal and the surface of the photonic chip 102 may be too small, requiring a longer horizontal propagation distance to exit the package structure and increasing the risk of optical path loss. Therefore, in this embodiment, the first acute angle is between 30 and 60 degrees. Preferably, the first acute angle is 45 degrees.

[0067] It should be noted that the light-transmitting cover 140 is used to seal and protect the light port 150 and the light path steering element 122 below it, providing a physical barrier to prevent contamination and mechanical damage. At the same time, the light-transmitting cover 140 itself serves as a light window, providing a low-loss transmission channel for the light signal after the direction is changed, and guiding the light signal to the light-transmitting side 141.

[0068] It should also be noted that the height of the light-transmitting cover 140 is lower than the height of the functional chip 110, so that the top of the functional chip 110 can protrude above the light-transmitting cover 140. Thus, in the process of forming the package structure, a heat sink or thermal interface material can be installed on the top of the functional chip 110, establishing an efficient heat dissipation path from the functional chip 110 to the outside of the package and optimizing the heat dissipation performance.

[0069] In this embodiment, the light-transmitting cover 140 is located above the front side 181 of the photonic chip 102.

[0070] In this embodiment, the light-transmitting cover 140 covers the reflective surface.

[0071] Specifically, the light-transmitting cover 140 covers the reflective surface, which can provide direct protection for the reflective surface of the light path turning element 122, preventing it from being contaminated by the molding compound or physically scratched in subsequent molding processes, and ensuring the reliability of the light path turning function.

[0072] In this embodiment, the material of the light-transmitting cover 140 includes one or more of glass, quartz, and optical polymers.

[0073] It should be noted that glass, quartz, and optical polymers have high transmittance and low optical loss in the wavelength range of optical signals. At the same time, glass, quartz, and optical polymers have good mechanical strength, chemical stability, and thermal stability, and can withstand the thermal and mechanical stress during the packaging process. Furthermore, the surfaces of glass and quartz are easy to be polished with high precision and coated with antireflective films and other optical treatments to further improve the optical performance of the light-transmitting side 141.

[0074] In this embodiment, the packaging structure further includes a molding compound 120, located above the front surface 181 of the photonic chip 102 exposed by the functional chip 110, the light path steering element 122, and the light-transmitting cover 140. The molding compound 120 covers the sidewall of the functional chip 110, the sidewall and top of the light path steering element 122, and the side and top of the light-transmitting cover 140. The molding compound 120 exposes the light-transmitting side surface 141 of the light-transmitting cover 140.

[0075] Specifically, the molding layer 120 is used to provide mechanical support, environmental protection and stress buffer for the photonic chip 102, functional chip 110, optical path steering element 122 and light-transmitting cover 140, and to solidify the photonic chip 102, functional chip 110, optical path steering element 122 and light-transmitting cover 140 into an integral package, thereby improving the mechanical strength and reliability of the structure.

[0076] It should be noted that the plastic encapsulation layer 120 exposes the light-transmitting side 141 of the light-transmitting cover 140, ensuring that the light signal guided to the light-transmitting side 141 by the light path steering element 122 can be exported out of the package body without obstruction, or allowing external light signals to be introduced without obstruction.

[0077] In this embodiment, the material of the molding layer 120 includes molding compound.

[0078] Specifically, molding compounds (such as molding compounds) can form dense, robust packages with good electrical insulation and some heat dissipation capabilities.

[0079] In this embodiment, the molding layer 120 material includes epoxy resin. Epoxy resin, as the main matrix material of the molding compound, has good adhesion, mechanical strength, electrical insulation and moisture resistance.

[0080] In this embodiment, the packaging structure further includes a transparent adhesive layer disposed on the surface of the photonic chip 102, and the light-transmitting cover 140 is fixed to the photonic chip 102 by the transparent adhesive layer.

[0081] It should be noted that the transparent adhesive layer is used to achieve mechanical fixation and sealing between the light-transmitting cover 140 and the photonic chip 102. At the same time, the transparent adhesive layer has transparent properties and will not block or significantly affect the transmission of optical signals from the optical port 150 to the optical path steering element 122.

[0082] In this embodiment, the material of the transparent adhesive layer can be an optically transparent adhesive, such as UV-curable or thermosetting silicone-based optical adhesive, epoxy optical adhesive, etc. These materials have appropriate bonding strength and good optical transmittance after curing.

[0083] In this embodiment, the packaging structure further includes a first conductive bump 180, which is disposed between the functional chip 110 and the photonic chip 102, and the functional chip 110 is electrically connected to the photonic chip 102 through the first conductive bump 180.

[0084] Specifically, the first conductive bump 180 is used to provide a vertical electrical interconnection path between the functional chip 110 and the photonic chip 102, so as to realize the transmission of power, ground and high-speed electrical signals.

[0085] In this embodiment, the material of the first conductive bump 180 can be solder (such as tin-silver-copper alloy), copper pillar, or a combination thereof with a solder cap. The first conductive bump 180 can form a reliable electrical and mechanical connection through processes such as reflow soldering.

[0086] In this embodiment, the packaging structure further includes a bottom filling layer 116, which is located on the photonic chip 102 and covers the sidewalls of the first conductive bump 180 and the functional chip 110.

[0087] It should be noted that the bottom filling layer 116 is used to fill the gap between the functional chip 110 and the photonic chip 102, cover and protect the first conductive bump 180, disperse the thermomechanical stress caused by the mismatch of the thermal expansion coefficients of the materials, thereby significantly improving the reliability of the first conductive bump 180.

[0088] In this embodiment, the material of the bottom filler layer 116 includes epoxy resin.

[0089] Specifically, epoxy resin has the characteristic of good fluidity. Epoxy resin with good fluidity can fully penetrate into the gaps of the first conductive bump 180 and form a solid support after curing.

[0090] In this embodiment, the packaging structure further includes a second conductive bump 101 located on the back surface 182 of the photonic chip 102, and the second conductive bump 101 is electrically connected to the back surface 182 of the photonic chip 102.

[0091] It should be noted that the second conductive bump 101 is used as an external interface for electrically connecting the photonic chip 102 and even the entire package to an external system (such as the substrate 100), and to bring out the signals and power of the photonic chip 102.

[0092] In this embodiment, the material of the second conductive bump 101 can be solder (such as tin-silver-copper alloy), copper pillar, or a combination thereof.

[0093] In this embodiment, the packaging structure further includes a substrate 100, and the package consisting of the photonic chip 102, the functional chip 110, the optical path steering element 122, and the light-transmitting cover 140 is disposed on the substrate 100, and the second conductive bump 101 is electrically connected to the substrate 100.

[0094] Specifically, the substrate 100 is used to provide mechanical support, electrical interconnection and heat dissipation channels for the package, and its internal wiring layer is electrically connected to the second conductive bump 101.

[0095] In this embodiment, the substrate 100 includes a printed circuit board (PCB) or a circuit carrier board.

[0096] It should be noted that printed circuit boards are relatively inexpensive and suitable for many applications, while circuit carriers can provide higher density interconnects and better electrical performance, making them suitable for high-performance, highly integrated packaging requirements.

[0097] like Figure 2 As shown, in other embodiments, the optical port 150 may also be located on the back side 182 of the photonic chip 102.

[0098] It should be noted that by placing the optical port 150 on the back side 182 of the photonic chip 102, and importing or exporting optical signals from the back side 182 of the photonic chip 102, this layout can completely free up the space on the front side 181 of the photonic chip 102. This allows the area above the front side 181 to focus more on the stacking of the functional chips 110 and the arrangement of heat dissipation structures (such as heat sinks). This avoids potential interference between the optical path on the front side 181 and the dense stack of functional chips 110 in physical space, thereby simplifying the packaging process complexity and difficulty of the front side 181.

[0099] In other embodiments, the light path steering element 122 and the light-transmitting cover 140 are both located below the back surface 182 of the photonic chip 102.

[0100] Specifically, the optical path steering element 122 and the light-transmitting cover 140 are disposed below the back surface 182 of the photonic chip 102, which allows the optical signal emitted from the optical port 150 of the back surface 182 to be immediately received by the optical path steering element 122 and its direction to be changed, or the external optical signal to be directly coupled into the optical port 150 of the back surface 182 after being deflected.

[0101] The packaging structure further includes a molding layer 120, located above the front side 181 of the exposed photonic chip 102 of the functional chip 110, and the molding layer 120 covers the sidewall of the functional chip 110.

[0102] Specifically, the molding layer 120 is used to provide mechanical support, environmental protection and stress buffer for the photonic chip 102 and the functional chip 110, integrating the photonic chip 102 and the functional chip 110 into a whole package, thereby improving the mechanical strength and reliability of the structure.

[0103] Accordingly, embodiments of the present invention also provide a method for forming an encapsulation structure.

[0104] Figure 3 This is a flowchart of the steps corresponding to one embodiment of the method for forming the packaging structure of the present invention.

[0105] In this embodiment, the method for forming the packaging structure includes the following basic steps: Step S1: Provide a photonic chip, the photonic chip having an optical port; Step S2: At least one functional chip is disposed on the top surface of the photonic chip, and the functional chip is electrically connected to the photonic chip; Step S3: Set an optical path steering element on the light output or input path of the optical port of the photonic chip. The optical path steering element is configured to change the propagation direction of the optical signal emitted from or introduced into the optical port. Step S4: A light-transmitting cover is provided on the surface of the photonic chip. The light-transmitting cover covers the light port and the light path steering element. The height of the light-transmitting cover is lower than the height of the functional chip. The light signal whose propagation direction is changed by the light path steering element is exported or imported through at least one light-transmitting side of the light-transmitting cover.

[0106] Specifically, an optical path steering element is provided on the light output or input path of the optical port of the photonic chip. The optical path steering element is configured to change the propagation direction of the optical signal emitted from or introduced into the optical port. A light-transmitting cover is provided on the surface of the photonic chip, covering the optical port and the optical path steering element. The height of the light-transmitting cover is lower than the height of the functional chip. The optical signal whose propagation direction is changed by the optical path steering element is exported or introduced through at least one light-transmitting side of the light-transmitting cover, so that the introduction or export of the optical signal is transferred from the top surface of the package structure to the side surface. This protects the light-transmitting cover and the optical path steering element during wafer thinning and other processes, reducing the risk of damage or breakage to the light-transmitting cover and the optical path steering element, thereby improving the reliability of the package structure and the transmission quality of the optical signal in the package structure.

[0107] in, Figures 4 to 9 The diagram shows the structural schematics corresponding to each step in the first embodiment of the method for forming the packaging structure according to an embodiment of the present invention.

[0108] refer to Figure 4 A photonic chip 202 is provided, wherein the photonic chip 202 has an optical port 250.

[0109] It should be noted that the photonic chip 202, as the core device for realizing photoelectric signal conversion or optical signal processing, is used to provide optical signal generation, modulation, reception or routing functions for the entire packaging structure.

[0110] Specifically, the optical port 250 provides a channel for optical signals to enter or exit the internal optical waveguide of the photonic chip 202.

[0111] In this embodiment, the optical port 250 includes a grating coupler.

[0112] It should be noted that the optical port 250 is a grating coupler, which can efficiently couple the optical signal transmitted in the waveguide of the photonic chip 202 along the direction parallel to the surface of the photonic chip 202 into an optical signal propagating outward along the direction perpendicular to the chip surface, or couple externally incident optical signals into the chip waveguide using the principle of diffraction.

[0113] In this embodiment, in the step of providing the photonic chip 202, the photonic chip 202 includes a front side 281 and a back side 282 opposite to the front side 281, and the optical port 250 is located on the front side 281 of the photonic chip 202.

[0114] In this embodiment, the optical port 250 is located on the front side 281 of the photonic chip 202.

[0115] Specifically, by placing the optical port 250 on the front side 281 of the photonic chip 202, it can be monolithically integrated with other electronic components (such as waveguides) placed on the front side 281 to achieve a more compact and lower loss optical path interconnection. At the same time, it is convenient to place optical path steering elements and light-transmitting covers on the front side 281 of the photonic chip 202.

[0116] In this embodiment, a second conductive bump 201 is formed on the back surface 282 of the photonic chip 202, and the second conductive bump 201 is electrically connected to the back surface 282 of the photonic chip 202.

[0117] It should be noted that the second conductive bump 201 is used as an external interface for electrically connecting the photonic chip 202 and even the entire package to an external system (such as a substrate), and to bring out the signals and power of the photonic chip 202.

[0118] In this embodiment, the material of the second conductive bump 201 can be solder (such as tin-silver-copper alloy), copper pillar, or a combination thereof.

[0119] refer to Figure 5 At least one functional chip 210 is disposed on the top surface of the photonic chip 202, and the functional chip 210 is electrically connected to the photonic chip 202.

[0120] It should be noted that the functional chip 210 is used to provide the necessary control, drive, signal processing, data storage or computing support for the photonic chip 202, such as driving the photonic modulator, processing the signals received by the photodetector, or providing coprocessing capabilities for photonic computing, thereby realizing the complex system functions of optoelectronic collaboration.

[0121] In this embodiment, the functional chip 210 is disposed on the front side 281 of the photonic chip 202.

[0122] The specific type of functional chip 210 can be selected according to actual needs. In this embodiment, functional chip 210 may include one or more of the following: ASIC (Application-Specific Integrated Circuit) chip, HBM (High Bandwidth Memory) chip, CPU (Central Processing Unit) chip, GPU (Graphics Processing Unit) chip, and FPGA (Field-Programmable Gate Array) chip.

[0123] In this embodiment, in the step of setting at least one functional chip 210 on the top surface of the photonic chip 202, a first conductive bump 280 is also formed on the surface of the functional chip 210, and the functional chip 210 is electrically connected to the photonic chip 202 through the first conductive bump 280.

[0124] Specifically, the first conductive bump 280 is used to provide a vertical electrical interconnection path between the functional chip 210 and the photonic chip 202, so as to realize the transmission of power, ground and high-speed electrical signals.

[0125] In this embodiment, the material of the first conductive bump 280 can be solder (such as tin-silver-copper alloy), copper pillar, or a combination thereof with a solder cap. The first conductive bump 280 can form a reliable electrical and mechanical connection through processes such as reflow soldering.

[0126] refer to Figure 6 A bottom filling layer 216 is formed on the photonic chip 202 to cover the sidewalls of the first conductive bump 280 and the functional chip 210.

[0127] It should be noted that the bottom filling layer 216 is used to fill the gap between the functional chip 210 and the photonic chip 202, cover and protect the first conductive bump 280, disperse the thermomechanical stress caused by the mismatch of the thermal expansion coefficients of the materials, thereby significantly improving the reliability of the first conductive bump 280.

[0128] In this embodiment, the material of the bottom filler layer 216 includes epoxy resin.

[0129] Specifically, epoxy resin has the characteristic of good fluidity. Epoxy resin with good fluidity can fully penetrate into the gaps of the first conductive bump 280 and form a solid support after curing.

[0130] refer to Figure 7 A light path steering element 222 is provided on the light output or light input path of the light port 250 of the photonic chip 202. The light path steering element 222 is configured to change the propagation direction of the light signal emitted from or introduced into the light port 250. A light-transmitting cover 240 is provided on the surface of the photonic chip 202. The light-transmitting cover 240 covers the light port 250 and the light path steering element 222. The height of the light-transmitting cover 240 is lower than the height of the functional chip 210. The light signal whose propagation direction is changed by the light path steering element 222 is exported or imported through at least one light-transmitting side 241 of the light-transmitting cover 240.

[0131] It should be noted that a light path steering element 222 is provided on the light output or input path of the light port 250 of the photonic chip 202. The light path steering element 222 is configured to change the propagation direction of the light signal emitted from or introduced into the light port 250. A light-transmitting cover 240 is provided on the surface of the photonic chip 202, covering the light port 250 and the light path steering element 222. The height of the light-transmitting cover 240 is lower than the height of the functional chip 210. The light signal whose propagation direction is changed by the light path steering element 222 is exported or introduced through at least one light-transmitting side 241 of the light-transmitting cover 240, so that the introduction or export of the light signal is transferred from the top surface of the package structure to the side surface. This protects the light-transmitting cover 240 and the light path steering element 222 during wafer thinning and other processes, reducing the risk of damage or breakage to the light-transmitting cover 240 and the light path steering element 222, thereby improving the reliability of the package structure and the transmission quality of the light signal in the package structure.

[0132] Specifically, the optical path steering element 222 is used to receive the optical signal emitted from the optical port 250 of the photonic chip 202 and propagating along a first direction (e.g., vertical direction), and change its propagation direction to a second direction (e.g., horizontal direction) different from the first direction through reflection or diffraction, and finally guide the optical signal to the light-transmitting side 241 of the preset light-transmitting cover 240; or, in reverse, it turns the optical signal introduced from the light-transmitting side 241 and propagating along the second direction (e.g., vertical direction) and couples it into the optical port 250.

[0133] In this embodiment, during the step of setting the light path steering element 222 and the light-transmitting cover 240, both the light path steering element 222 and the light-transmitting cover 240 are located above the front surface 281 of the photonic chip 202.

[0134] In this embodiment, the optical path steering element 222 includes one or both of a prism and a diffraction grating.

[0135] It should be noted that prisms can achieve low-loss optical path deflection by utilizing the principle of total internal reflection, while diffraction gratings can achieve optical path deflection by utilizing their micro-nano structures. Both are mature and reliable optical components that are easy to integrate with packaging processes.

[0136] In this embodiment, the optical path steering element 222 has a reflective surface set at a first acute angle, and the first acute angle includes the angle between the surface of the photonic chip 202 and the optical path steering element 222. Specifically, by setting the reflective surface at a first acute angle, the transmission direction of the vertically incident light signal can be changed to horizontal emission.

[0137] It should be noted that the first acute angle should not be too large or too small. If the first acute angle is too large, the incident angle of the incident light signal on the reflecting surface may deviate from the optimal reflection conditions, resulting in a decrease in the light signal reflection efficiency and possible transmission loss of some light signals. Furthermore, an excessively large angle may require the light-transmitting cover 240 to occupy more space in the vertical direction, which is detrimental to the miniaturization of the package. If the first acute angle is too small, the angle between the propagation path of the redirected light signal and the surface of the photonic chip 202 may be too small, requiring a longer horizontal propagation distance to exit the package structure and increasing the risk of optical path loss. Therefore, in this embodiment, the first acute angle is between 30 and 60 degrees. Preferably, the first acute angle is 45 degrees.

[0138] It should be noted that the light-transmitting cover 240 is used to seal and protect the light port 250 and the light path steering element 222 below it, providing a physical barrier to prevent contamination and mechanical damage. At the same time, the light-transmitting cover 240 itself serves as a light window, providing a low-loss transmission channel for the light signal after the direction is changed, and guiding the light signal to the light-transmitting side 241.

[0139] It should also be noted that the height of the light-transmitting cover 240 is lower than the height of the functional chip 210, so that the top of the functional chip 210 can protrude above the light-transmitting cover 240. Thus, in the process of forming the package structure, a heat sink or thermal interface material can be installed on the top of the functional chip 210, establishing an efficient heat dissipation path from the functional chip 210 to the outside of the package and optimizing the heat dissipation performance.

[0140] In this embodiment, the light-transmitting cover 240 covers the reflective surface.

[0141] Specifically, the light-transmitting cover 240 covers the reflective surface, which can provide direct protection for the reflective surface of the light path steering element 222, preventing it from being contaminated by the molding compound or physically scratched in subsequent molding processes, and ensuring the reliability of the light path steering function.

[0142] In this embodiment, the material of the light-transmitting cover 240 includes one or more of glass, quartz, and optical polymers.

[0143] It should be noted that glass, quartz, and optical polymers have high transmittance and low optical loss in the optical signal wavelength range. At the same time, glass, quartz, and optical polymers have good mechanical strength, chemical stability, and thermal stability, and can withstand the thermal and mechanical stress during the packaging process. Furthermore, the surfaces of glass and quartz are easy to polish with high precision and be coated with anti-reflection films, etc., to further improve the optical performance of the light-transmitting side 241.

[0144] In this embodiment, the step of setting the light-transmitting cover 240 on the surface of the photonic chip 202 includes: setting a transparent adhesive layer on the surface of the photonic chip 202, setting the light-transmitting layer on the transparent adhesive layer, and fixing the light-transmitting cover 240 to the photonic chip 202 through the transparent adhesive layer.

[0145] It should be noted that the transparent adhesive layer is used to achieve mechanical fixation and sealing between the light-transmitting cover 240 and the photonic chip 202. At the same time, the transparent adhesive layer has transparent properties and will not block or significantly affect the transmission of optical signals from the optical port 250 to the optical path steering element 222.

[0146] In this embodiment, the material of the transparent adhesive layer can be an optically transparent adhesive, such as UV-curable or thermosetting silicone-based optical adhesive, epoxy optical adhesive, etc. These materials have appropriate bonding strength and good optical transmittance after curing.

[0147] refer to Figure 8 After setting the light path steering element 222 and the light-transmitting cover 240, the forming method further includes: forming a molding compound 220 above the front surface 281 of the photonic chip 202 exposed by the functional chip 210, the light path steering element 222 and the light-transmitting cover 240. The molding compound 220 covers the sidewall of the functional chip 210, the sidewall and top of the light path steering element 222, and the side and top of the light-transmitting cover 240, and the molding compound 220 exposes the light-transmitting side surface 241 of the light-transmitting cover 240.

[0148] Specifically, the molding layer 220 is used to provide mechanical support, environmental protection and stress buffer for the photonic chip 202, functional chip 210, optical path steering element 222 and light-transmitting cover 240, and to solidify the photonic chip 202, functional chip 210, optical path steering element 222 and light-transmitting cover 240 into an integral package, thereby improving the mechanical strength and reliability of the structure.

[0149] It should be noted that the plastic encapsulation layer 220 exposes the light-transmitting side 241 of the light-transmitting cover 240, ensuring that the light signal guided to the light-transmitting side 241 by the light path steering element 222 can be exported out of the package without obstruction, or allowing external light signals to be introduced without obstruction.

[0150] In this embodiment, the material of the molding layer 220 includes molding compound.

[0151] Specifically, molding compounds (such as molding compounds) can form dense, robust packages with good electrical insulation and some heat dissipation capabilities.

[0152] In this embodiment, the molding layer 220 material includes epoxy resin. Epoxy resin, as the main matrix material of the molding compound, has good adhesion, mechanical strength, electrical insulation and moisture resistance.

[0153] refer to Figure 9 The forming method further includes: providing a substrate 200; disposing of a package consisting of the photonic chip 202, the functional chip 210, the optical path steering element 222, and the light-transmitting cover 240 on the substrate 200, and the second conductive bump 201 being electrically connected to the substrate 200.

[0154] Specifically, the substrate 200 is used to provide mechanical support, electrical interconnection and heat dissipation channels for the package, and its internal wiring layer is electrically connected to the second conductive bump 201.

[0155] In this embodiment, the substrate 200 includes a printed circuit board (PCB) or a circuit carrier board.

[0156] It should be noted that printed circuit boards are relatively inexpensive and suitable for many applications, while circuit carriers can provide higher density interconnects and better electrical performance, making them suitable for high-performance, highly integrated packaging requirements.

[0157] Figure 10 This illustration shows a schematic diagram of the structure corresponding to each step in the second embodiment of the method for forming the packaging structure according to an embodiment of the present invention. The similarities between this embodiment and the first embodiment will not be repeated here; the differences are as follows: like Figure 10 As shown, the optical port 250 is located on the back side 282 of the photonic chip 202.

[0158] It should be noted that by placing the optical port 250 on the back side 282 of the photonic chip 202, and importing or exporting optical signals from the back side 282 of the photonic chip 202, this layout can completely free up the space on the front side 281 of the photonic chip 202. This allows the area above the front side 281 to focus more on the stacking of the functional chips 210 and the arrangement of heat dissipation structures (such as heat sinks). This avoids potential interference between the optical path on the front side 281 and the dense stack of functional chips 210 in physical space, thereby simplifying the packaging process complexity and difficulty of the front side 281.

[0159] like Figure 10 As shown, in the step of setting the light path steering element 222 and the light-transmitting cover 240, both the light path steering element 222 and the light-transmitting cover 240 are located below the back surface 282 of the photonic chip 202.

[0160] Specifically, the optical path steering element 222 and the light-transmitting cover 240 are disposed below the back surface 282 of the photonic chip 202, which allows the optical signal emitted from the optical port 250 of the back surface 282 to be immediately received by the optical path steering element 222 and its direction to be changed, or the external optical signal to be directly coupled into the optical port 250 of the back surface 282 after being steering.

[0161] like Figure 10 As shown, after setting the light path steering element 222 and the light-transmitting cover 240, the forming method further includes: forming a molding compound 220 above the front side 281 of the exposed photonic chip 202 of the functional chip 210, the molding compound 220 covering the sidewall of the functional chip 210.

[0162] It should be noted that the molding layer 220 is used to provide mechanical support, environmental protection and stress buffer for the photonic chip 202 and the functional chip 210, and to integrate and solidify the photonic chip 202 and the functional chip 210 into a whole package, thereby improving the mechanical strength and reliability of the structure.

[0163] While the above disclosure is provided, it is not limited thereto. Any person skilled in the art may make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure shall be determined by the scope defined in the claims.

Claims

1. A packaging structure, characterized in that, include: A photonic chip, wherein the photonic chip has an optical port; At least one functional chip is disposed on the top surface of the photonic chip, and the functional chip is electrically connected to the photonic chip; An optical path steering element is disposed on the path of light output or light input of the optical port and is configured to change the propagation direction of the optical signal emitted from or introduced into the optical port. A light-transmitting cover covers the light port and the light path steering element. The height of the light-transmitting cover is lower than the height of the functional chip. The light signal whose propagation direction is changed by the light path steering element is exported or imported through at least one light-transmitting side of the light-transmitting cover.

2. The packaging structure as described in claim 1, characterized in that, The photonic chip has a front side and a back side opposite to the front side; The optical port is located on the front of the photonic chip; The optical path steering element and the light-transmitting cover are both located on the front and above the photonic chip; The packaging structure further includes: a molding layer located above the front surface of the photonic chip exposed by the functional chip, the optical path steering element, and the light-transmitting cover, and the molding layer covers the sidewall of the functional chip, the sidewall and top of the optical path steering element, and the side and top of the light-transmitting cover, and the molding layer exposes the light-transmitting side of the light-transmitting cover. or, The optical port is located on the back of the photonic chip; The optical path steering element and the light-transmitting cover are both located below the back of the photonic chip; The packaging structure further includes a molding layer located above the exposed front of the photonic chip of the functional chip, and the molding layer covers the sidewall of the functional chip.

3. The packaging structure as described in claim 1, characterized in that, The optical path steering element includes one or both of a prism and a diffraction grating.

4. The packaging structure as described in claim 1, characterized in that, The optical path steering element has a reflective surface set at a first acute angle, and the first acute angle includes the angle between the surface of the photonic chip and the optical path steering element; The light-transmitting cover covers the reflective surface.

5. The packaging structure as described in claim 4, characterized in that, The first acute angle is between 30 and 60 degrees.

6. The packaging structure as described in claim 1, characterized in that, The optical port includes a grating coupler.

7. The packaging structure as described in claim 1, characterized in that, The material of the light-transmitting cover includes one or more of glass, quartz, and optical polymers.

8. The packaging structure as described in claim 1, characterized in that, The packaging structure further includes a transparent adhesive layer disposed on the surface of the photonic chip, and the light-transmitting cover is fixed to the photonic chip by the transparent adhesive layer.

9. The packaging structure as described in claim 1, characterized in that, The packaging structure further includes a first conductive bump disposed between the functional chip and the photonic chip, wherein the functional chip is electrically connected to the photonic chip through the first conductive bump.

10. The packaging structure as described in claim 9, characterized in that, The packaging structure further includes a bottom filler layer, located on the photonic chip and covering the sidewalls of the first conductive bump and the functional chip.

11. The packaging structure as described in claim 1, characterized in that, The photonic chip has a front side and a back side opposite to the front side; The functional chip is disposed on the front side of the photonic chip; The packaging structure further includes a second conductive bump located on the back side of the photonic chip, and the second conductive bump is electrically connected to the back side of the photonic chip.

12. The packaging structure as described in claim 11, characterized in that, The packaging structure further includes a substrate, on which the package consisting of the photonic chip, the functional chip, the optical path steering element, and the light-transmitting cover is disposed, and the second conductive bump is electrically connected to the substrate.

13. A method for forming an encapsulation structure, characterized in that, include: A photonic chip is provided, the photonic chip having an optical port; At least one functional chip is disposed on the top surface of the photonic chip, and the functional chip is electrically connected to the photonic chip; An optical path steering element is provided on the light output or light input path of the optical port of the photonic chip. The optical path steering element is configured to change the propagation direction of the optical signal emitted from or introduced into the optical port. A light-transmitting cover is disposed on the surface of the photonic chip, the light-transmitting cover covering the optical port and the optical path steering element, the height of the light-transmitting cover being lower than the height of the functional chip, and the optical signal whose propagation direction is changed by the optical path steering element being exported or imported through at least one light-transmitting side of the light-transmitting cover.

14. The method for forming the packaging structure as described in claim 13, characterized in that, In the step of providing a photonic chip, the photonic chip includes a front side and a back side opposite to the front side, and the optical port is located on the front side of the photonic chip; In the step of setting the optical path steering element and the light-transmitting cover, both the optical path steering element and the light-transmitting cover are located above the front of the photonic chip; After setting the optical path steering element and the light-transmitting cover, the forming method further includes: forming a molding compound layer above the front surface of the photonic chip exposed by the functional chip, the optical path steering element and the light-transmitting cover, the molding compound layer covering the sidewall of the functional chip, covering the sidewall and top of the optical path steering element, and covering the side and top of the light-transmitting cover, and the molding compound layer exposing the light-transmitting side surface of the light-transmitting cover; or, In the step of providing a photonic chip, the photonic chip includes a front side and a back side opposite to the front side, and the optical port is located on the back side of the photonic chip; In the step of setting the optical path steering element and the light-transmitting cover, both the optical path steering element and the light-transmitting cover are located below the back surface of the photonic chip; After setting the optical path steering element and the light-transmitting cover, the forming method further includes: forming a molding layer above the front side of the exposed photonic chip of the functional chip, the molding layer covering the sidewall of the functional chip.

15. The method for forming the packaging structure as described in claim 13, characterized in that, The optical path steering element includes one or both of a prism and a diffraction grating.

16. The method for forming the packaging structure as described in claim 13, characterized in that, The optical path steering element has a reflective surface set at a first acute angle, and the first acute angle includes the angle between the surface of the photonic chip and the optical path steering element; The light-transmitting cover covers the reflective surface.

17. The method for forming the packaging structure as described in claim 16, characterized in that, The first acute angle is between 30 and 60 degrees.

18. The method for forming the packaging structure as described in claim 13, characterized in that, The optical port includes a grating coupler.

19. The method for forming the packaging structure as described in claim 13, characterized in that, The material of the light-transmitting cover includes one or more of glass, quartz, and optical polymers.

20. The method for forming the packaging structure as described in claim 13, characterized in that, The step of setting the light-transmitting cover on the surface of the photonic chip includes: setting a transparent adhesive layer on the surface of the photonic chip, setting the light-transmitting layer on the transparent adhesive layer, and fixing the light-transmitting cover to the photonic chip through the transparent adhesive layer.

21. The method for forming the packaging structure as described in claim 13, characterized in that, In the step of setting at least one functional chip on the top surface of the photonic chip, a first conductive bump is also formed on the surface of the functional chip, and the functional chip is electrically connected to the photonic chip through the first conductive bump.

22. The method for forming the packaging structure as described in claim 13, characterized in that, After setting the functional chip and before setting the optical path steering element and the light-transmitting cover, the method further includes: forming a bottom filling layer on the photonic chip that covers the first conductive bump and the sidewall of the functional chip.

23. The method for forming the packaging structure as described in claim 13, characterized in that, In the step of providing the photonic chip, the photonic chip has a front side and a back side opposite to the front side, a second conductive bump is formed on the back side of the photonic chip, and the second conductive bump is electrically connected to the back side of the photonic chip.

24. The method for forming the packaging structure as described in claim 23, characterized in that, The forming method further includes: providing a substrate; disposing of the package consisting of the photonic chip, the functional chip, the optical path steering element, and the light-transmitting cover on the substrate, wherein the second conductive bump is electrically connected to the substrate.

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