Package structure and manufacturing method therefor

Abstract

Disclosed in the present application are a package structure and a manufacturing method therefor. The package structure comprises: a first substrate, an electronic integrated circuit chip, a photonic integrated circuit chip and a second substrate, which are sequentially stacked, wherein the first substrate has a bearing face and an opposite bottom face, the electronic integrated circuit chip is arranged on the bearing face, and the second substrate has a first surface close to the first substrate and a second surface away from the first substrate; a flexible circuit board, which has a first end and a second end, wherein the first end thereof is electrically connected to the first substrate; and a light source, which is arranged on a third surface of the second substrate, wherein the light source is electrically connected to the second end of the flexible circuit board, and the light source is optically coupled to the photonic integrated circuit chip.

Description

Packaging structure and manufacturing method

[0001] This application claims priority to Chinese Patent Application No. 202510086127.8, filed on January 17, 2025, entitled "Packaging Structure and Manufacturing Method Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of semiconductor technology, and in particular to a packaging structure and its manufacturing method. Background Technology

[0003] Photonic integrated circuit chips can be used in optical computing or optical transmission. Co-Packaged Optics (CPO) integrates photonic integrated circuit (PIC) chips and electronic integrated circuit (EIC) chips into a single package structure, which can improve data transmission rate and product integration. Summary of the Invention

[0004] This application provides a packaging structure and its manufacturing method, aiming to provide a co-packaging structure for photonic integrated circuit chips and electronic integrated circuit chips with high integration and excellent performance.

[0005] According to a first aspect of this application, this application provides a packaging structure comprising: a first substrate, an electronic integrated circuit chip, a photonic integrated circuit chip, and a second substrate stacked sequentially; wherein the first substrate has a bearing surface and an opposing bottom surface, the electronic integrated circuit chip is disposed on the bearing surface, and the second substrate has a first surface close to the first substrate and a second surface away from the first substrate; a flexible circuit board having a first end and a second end, the first end of which is electrically connected to the first substrate; and a light source disposed on a third surface of the second substrate, the light source being electrically connected to the second end of the flexible circuit board, and the light source being optically coupled to the photonic integrated circuit chip.

[0006] In some embodiments, the flexible circuit board has a third surface and an opposing fourth surface.

[0007] In some embodiments, the first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate via a third surface, and the second end of the flexible circuit board is electrically connected to the second surface of the second substrate via a third surface.

[0008] In some embodiments, the packaging structure further includes a second connecting line, the second substrate including a wiring structure; the second connecting line has a first end and a second end, the first end being electrically connected to the light source, the second end being electrically connected to a first surface of the second substrate, and the second end being electrically connected to the flexible circuit board through the wiring structure of the second substrate; wherein the light source is electrically connected to the flexible circuit board through the second end of the second connecting line, and is electrically connected to the first substrate via the flexible circuit board.

[0009] In some embodiments, the wiring structure includes conductive holes located within the second substrate.

[0010] In some embodiments, the second end of the flexible circuit board is electrically connected to the conductive hole through a portion of a wiring structure disposed on the second surface of the second substrate, and is electrically connected to the second end of the second connecting line via the conductive hole.

[0011] In some embodiments, the first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate via a third surface, and the second end of the flexible circuit board is electrically connected to the first surface of the second substrate via a fourth surface.

[0012] In some embodiments, the packaging structure further includes a second connecting line, the second substrate including a wiring structure; the second connecting line has a first end and a second end, the first end being electrically connected to the light source, the second end being electrically connected to a first surface of the second substrate, and the second end being electrically connected to the flexible circuit board through the wiring structure of the second substrate; wherein the light source is electrically connected to the flexible circuit board through the second end of the second connecting line, and is electrically connected to the first substrate via the flexible circuit board.

[0013] In some embodiments, the wiring structure includes a metal conductor layer located on a first surface of the second substrate.

[0014] In some embodiments, the second end of the flexible circuit board is electrically connected to the second end of the second connecting line through a metal wire layer disposed on the first surface of the second substrate.

[0015] In some embodiments, the packaging structure further includes a second connecting line having a first end and a second end, the first end of which is electrically connected to the light source.

[0016] In some embodiments, the second end of the flexible circuit board is electrically connected to the second end of the second connecting line via a fourth surface.

[0017] In some embodiments, the first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate via a third surface.

[0018] In some embodiments, the first end of the flexible circuit board is electrically connected to the bottom surface of the first substrate via a fourth surface.

[0019] In some embodiments, the first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate via a fourth surface.

[0020] In some embodiments, the second end of the flexible circuit board is fixed to the first surface of the second substrate via a third surface.

[0021] In some implementations, the second connecting wire is a gold wire.

[0022] In some embodiments, the photonic integrated circuit chip includes an optical port, and the projection of the optical port onto the carrier surface does not overlap on a plane parallel to the carrier surface.

[0023] In some embodiments, the optical port extends beyond the edge of the bearing surface.

[0024] In some embodiments, the first substrate includes a first opening, and the optical port overlaps with the projection of the first opening on a plane parallel to the bearing surface.

[0025] In some embodiments, the photonic integrated circuit chip includes an optical port, which is an edge coupler.

[0026] In some embodiments, the projection of the light source onto the bearing surface does not overlap on a plane parallel to the bearing surface.

[0027] In some embodiments, the packaging structure further includes: a lens and an isolator arranged sequentially in the optical coupling path between the light source and the photonic integrated circuit chip; the lens and the isolator are fixed to a first surface of the second substrate.

[0028] In some embodiments, the projection of the lens onto the bearing surface does not overlap with the projection of the bearing surface on a plane parallel to the bearing surface, and the projection of the isolator onto the bearing surface does not overlap with the projection of the bearing surface.

[0029] In some embodiments, the first substrate includes a printed circuit board or an organic substrate.

[0030] In some embodiments, the second substrate includes a rigid substrate.

[0031] According to a second aspect of the present invention, this application provides a method for manufacturing a packaging structure, comprising: fixing an electronic integrated circuit chip and a photonic integrated circuit chip together; providing a first substrate having a bearing surface; fixing a combination of the electronic integrated circuit chip and the photonic integrated circuit chip to the first substrate, wherein the electronic integrated circuit chip is mounted to the bearing surface of the first substrate; providing a second substrate having a first surface and an opposing second surface; fixing the photonic integrated circuit chip and the second substrate such that the first surface of the second substrate is close to the bearing surface of the first substrate; fixing a first end and a second end of a flexible circuit board to the first substrate and the second substrate respectively; and mounting a light source on the first surface of the second substrate to form an optical coupling path between the light source and the photonic integrated circuit chip.

[0032] In some embodiments, after the second end of the flexible circuit board is fixed to the second substrate, the light source is electrically connected to the second end of the flexible circuit board by wire bonding.

[0033] This application can achieve at least the following technical effects:

[0034] By stacking a first substrate, an electronic integrated circuit chip, a photonic integrated circuit chip, and a second substrate, along with a light source disposed on the second surface of the second substrate and electrically connected to the first substrate via a flexible circuit board, a packaging structure is achieved that co-packages the photonic integrated circuit chip and the electronic integrated circuit chip. While enabling the photonic integrated circuit chip to be flip-mounted onto the electronic integrated circuit chip via the second substrate, optical components such as the light source can also be disposed on the second substrate to form an optical coupling path between them and the photonic integrated circuit chip. This removes the restriction on the mounting position of optical components such as the light source and achieves better optical coupling. Furthermore, since the second surface of the second substrate and the bearing surface of the first substrate are on opposite sides, direct wire bonding between them is not possible. The flexible circuit board enables electrical connection between the bearing surface of the first substrate and the second surface of the second substrate, and the light source is then electrically connected to the flexible circuit board. This solves the problem that when the laser chip and the photonic integrated circuit chip are mounted on the second surface of the second substrate, they cannot be directly electrically connected to the bottom printed circuit board or organic substrate. Attached Figure Description

[0035] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0036] Figure 1 shows a schematic diagram of the packaging structure of a photonic integrated circuit chip and an electronic integrated circuit chip;

[0037] Figure 2 shows a schematic diagram of a packaging structure according to an embodiment of this application;

[0038] Figure 3 shows a schematic diagram of a packaging structure according to another embodiment of this application;

[0039] Figure 4 shows a schematic diagram of a packaging structure according to another embodiment of this application;

[0040] Figure 5 shows a schematic diagram of a packaging structure according to another embodiment of this application;

[0041] Figure 6 shows a schematic diagram of a packaging structure according to another embodiment of this application;

[0042] Figure 7 shows a schematic diagram of a packaging structure according to another embodiment of this application;

[0043] Figure 8 shows a schematic diagram of a packaging structure provided according to another embodiment of this application.

[0044] The meanings of the reference numerals in the attached figures are as follows:

[0045] 10: First substrate;

[0046] 11: The first opening;

[0047] 20: Second substrate;

[0048] 21: Wiring structure;

[0049] 30: Electronic integrated circuit chips;

[0050] 40: Photonic integrated circuit chip;

[0051] 51: Flexible circuit board;

[0052] 52: Second connecting line;

[0053] 60: Light source;

[0054] 61: Carrier plate;

[0055] 71: Isolator;

[0056] 72: Lens. Embodiments of the present invention

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0058] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0059] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In this embodiment, the simulated display screen touch unit is connected to the head tracking unit to obtain the movement path of the sensing cursor in the display device.

[0060] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0061] The following disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0062] Figure 1 shows a schematic diagram of a packaging structure for a photonic integrated circuit chip and an electronic integrated circuit chip. The inventors of this application have discovered that in the shared packaging structure of the photonic integrated circuit chip and the electronic integrated circuit chip, a tungsten copper substrate 80' is placed below the opening of the printed circuit board 10'. The photonic integrated circuit chip 40' is attached to the tungsten copper substrate 80', and the electronic integrated circuit chip 30' is flip-chip mounted on the photonic integrated circuit chip 40'. Related components such as the light source 60', lens 72', and isolator 71' are attached to the tungsten copper substrate 80' near the light inlet of the photonic integrated circuit chip 40'. However, as the number of channels in the electronic integrated circuit chip 30' and the rate per channel increases, the required number of pins also increases, and the above packaging structure is gradually becoming inadequate for new application requirements.

[0063] This application provides a packaging structure. Figure 2 shows a schematic diagram of a packaging structure according to an embodiment of this application. The packaging structure includes a first substrate 10, an electronic integrated circuit chip 30, a photonic integrated circuit chip 40, and a second substrate 20 stacked sequentially. The first substrate 10 has a bearing surface and an opposing bottom surface. The electronic integrated circuit chip 30 is disposed on the bearing surface. The second substrate 20 has a first surface close to the first substrate 10 and a second surface away from the first substrate 10. A flexible circuit board 51 has a first end and a second end, with its first end electrically connected to the first substrate 10. A light source 60 is disposed on the third surface of the second substrate 20, electrically connected to the second end of the flexible circuit board 51, and optically coupled to the photonic integrated circuit chip 40. It should be noted that there is an electrical bonding structure (not shown in Figure 2) between the photonic integrated circuit chip 40 and the electronic integrated circuit chip 30, and an electrical bonding structure (not shown in Figure 2) between the electronic integrated circuit chip 30 and the first substrate 10. The photonic integrated circuit chip 40 is electrically connected to the electronic integrated circuit through the bonding structure for current / signal transmission, and the electronic integrated circuit chip 30 is electrically connected to the first substrate 10 through the bonding structure for current / signal transmission. For example, the first substrate 10 is a PCB (Printed Circuit Board), and the second substrate 20 is a carrier substrate that carries the light source 60, as well as the lens 72 and the isolator 71.

[0064] In some embodiments, the flexible printed circuit board 51 (FPC) is a circuit board made with organic materials such as polyimide or polyester film as the substrate. Metal layers are printed on the flexible substrate through processes such as etching and electroplating to form circuit lines, and a cover layer is provided outside the metal layers to protect the circuit lines. Compared to rigid printed circuit boards, the flexible printed circuit board 51 can be bent and folded within certain limits without damaging its internal circuit lines.

[0065] In the embodiment shown in Figure 2, the flexible circuit board 51 has a third surface and an opposing fourth surface. A first end of the flexible circuit board 51 is electrically connected to the bearing surface of the first substrate 10 via the third surface, and a second end of the flexible circuit board 51 is electrically connected to the second surface of the second substrate 20 via the third surface. A circuit connection line is provided between the first and second ends of the flexible circuit board 51. When the first and second ends of the flexible circuit board 51 are electrically connected to the first substrate 10 and the second substrate 20 respectively, an electrical connection between the first substrate 10 and the second substrate 20 is achieved through the circuit connection line of the flexible circuit board 51.

[0066] In some embodiments, pads are provided on the third surface of the first end of the flexible circuit board 51, and the circuit connection lines in the flexible circuit board 51 are electrically connected to the bearing surface of the first substrate 10 by soldering through the pads. The pad placement surfaces at both ends of the flexible circuit board 51 can be changed by the via and layer-change wiring design inside the flexible circuit board 51. Specifically, the pads at the first end of the flexible circuit board 51 can be disposed on the third or fourth surface, and the pads at the second end of the flexible circuit board 51 can be disposed on the third or fourth surface. Furthermore, the pad placement surfaces at the first and second ends of the flexible circuit board 51 can be freely combined. For example, the combination can be that the pads at the first end of the flexible circuit board 51 are disposed on the third surface, and the pads at the second end of the flexible circuit board 51 are disposed on the fourth surface. Alternatively, both the pads at the first and second ends of the flexible circuit board 51 are disposed on the third surface. Alternatively, both the pads at the first and second ends of the flexible circuit board 51 are disposed on the fourth surface. Alternatively, the pads at the first end of the flexible circuit board 51 are disposed on the fourth surface, and the pads at the second end of the flexible circuit board 51 are disposed on the third surface.

[0067] In the embodiment shown in FIG2, the packaging structure further includes a second connecting line 52, and the second substrate 20 includes a wiring structure 21. The second connecting line 52 has a first end and a second end. The first end is electrically connected to the light source 60, and the second end is electrically connected to a first surface of the second substrate 20. The second end is electrically connected to the flexible circuit board 51 through the wiring structure 21 of the second substrate 20. The light source 60 is electrically connected to the flexible circuit board 51 through the second end of the second connecting line 52, and is then electrically connected to the first substrate 10 via the flexible circuit board 51. In some embodiments, the second connecting line 52 is a gold wire.

[0068] In the embodiment shown in FIG2, since the light source 60 and the like are disposed on the first surface of the second substrate 20, it is also necessary to transmit the electrical signals on the second surface of the second substrate 20 to the first surface through the wiring structure 21. The wiring structure 21 may include a portion disposed on the second surface of the second substrate 20 and a conductive hole penetrating the second substrate 20. The second end of the flexible circuit board 51 is electrically connected to the conductive hole through a portion of the wiring structure 21 disposed on the second surface of the second substrate 20, and is electrically connected to the second end of the second connecting line 52 through the conductive hole. Exemplarily, the portion of the wiring structure 21 disposed on the second surface of the second substrate 20 may be a planar metal wire, and the conductive hole may be a through hole filled with conductive metal.

[0069] When bonding chips, conventional wire bonding technology can bond two planes on the same side. However, the gold wire used in conventional wire bonding has a limited design length. For example, if the height difference between two planes on the same side is too large, the required connection length exceeds the design limit of ordinary gold wire, making wire bonding impossible. The flexible circuit board 51, however, has no length limitation. Therefore, it can electrically connect the bearing surface of the first substrate 10 to the second surface of the second substrate 20. One end of the flexible circuit board 51 is fixed to the bearing surface of the first substrate 10, and the second end is fixed to the second surface of the second substrate 20, thus achieving electrical connection between the bearing surface of the first substrate 10 and the second surface of the second substrate 20. Then, the light source 60 is electrically connected to the flexible circuit board 51, solving the problem that when the laser chip and photonic integrated circuit chip 40 are mounted on the second surface of the second substrate 20, they cannot be directly electrically connected to the bottom printed circuit board or organic substrate.

[0070] Therefore, the flexible circuit board 51 and the second connecting line 52 facilitate the electrical connection requirements and provide a suitable electrical connection method.

[0071] In some embodiments, the first substrate 10 can be a printed circuit board (PCB) or an organic substrate. The organic substrate uses an organic polymer material as a matrix, such as polyimide (PI) or epoxy resin, and employs thin-film processes, such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), to deposit a metal thin film on the organic substrate to create conductive lines. Organic substrates have lower dielectric constants and dielectric losses, making them suitable for high-speed signal transmission. The first substrate 10 can also be provided with a power supply and electronic devices. The power supply and electronic devices are electrically connected to the conductive lines. The electronic devices can be resistors, capacitors, inductors, transistors, diodes, etc., which are not specified in this application.

[0072] In the embodiment shown in Figure 2, the electronic integrated circuit chip 30 can be fixed to the first substrate 10 by means of welding or bonding, and electrically connected to the conductive lines on the first substrate 10 through a bonding structure. Thus, the current / signal on the electronic integrated circuit chip 30 can be directly transmitted to the first substrate 10 without passing through the photonic integrated circuit chip 40. In some embodiments, the electronic integrated circuit chip 30 includes one or more active components and / or passive components. Examples of passive components include, but are not limited to, resistors, capacitors, and inductors. Examples of active components include, but are not limited to, diodes, field-effect transistors, and metal-oxide-semiconductor field-effect transistors.

[0073] In the embodiment shown in Figure 2, the photonic integrated circuit chip 40 is disposed on the electronic integrated circuit chip 30. Compared to the case shown in Figure 1 where the photonic integrated circuit chip 40' is disposed below the electronic integrated circuit chip 30', in this embodiment, the photonic integrated circuit chip 40 does not restrict the placement of other optical or electrical components. The photonic integrated circuit chip 40 and the electronic integrated circuit chip 30 are electrically connected via a bonding structure for information exchange. The photonic integrated circuit chip 40 may include a substrate, an optical modulator, an optical waveguide, an optical coupling structure, and a photodetector, etc.

[0074] In the embodiment shown in FIG2, the second substrate 20 is disposed on the photonic integrated circuit chip 40, having a first surface close to the first substrate 10 and a second surface away from the first substrate 10. In some embodiments, the second substrate 20 is a rigid substrate, for example, it can be a ceramic substrate. The second substrate 20 is used to carry the light source 60 and optical elements, so that the light signal emitted by the light source 60 is coupled to the photonic integrated circuit chip 40.

[0075] In some embodiments, the photonic integrated circuit chip 40 includes an optical port, and the projection of the optical port onto the plane parallel to the carrier surface does not overlap. The optical signal emitted by the light source 60 is coupled into the optical port via optical elements, etc. The optical port receives the optical signal and transmits it to an optical structure such as an optical waveguide inside the photonic integrated circuit chip 40 for processing. Exemplarily, the optical port can be an edge coupler, which performs lateral coupling when the optical signal enters through the edge coupler. In the embodiment shown in FIG2, by reasonably designing the positional relationship between the edge coupler and the light source 60, the optical signal emitted by the light source 60 can be laterally transmitted to the photonic integrated circuit chip 40 via optical elements using the edge coupler.

[0076] In the embodiment shown in Figure 2, the second substrate 20 extends beyond the edge of the first substrate 10, and the optical port of the photonic integrated circuit chip 40 extends beyond the edge of the bearing surface. For the portion of the second substrate 20 extending beyond the first substrate 10, since there are no other devices in the space below it, there is a larger accommodating space. Mounting the light source 60 and optical elements on the first surface of this portion of the second substrate 20 allows for compatibility with light sources 60 and optical elements of various sizes. Furthermore, during packaging, the entire packaging structure can be flipped so that the first surface of the portion of the second substrate 20 extending beyond the first substrate 10 is exposed. The pick-and-place machine and optical coupling stage can then precisely position and mount the light source 60 and optical elements onto the second substrate 20 using conventional processes. This packaging structure not only compatibility with existing mounting equipment and processes, reducing production costs, but also maintains good mounting accuracy. In addition, since the light source 60 and optical elements are mounted simultaneously with the photonic integrated circuit chip 40 on the same rigid substrate, it helps maintain the stability and reliability of the optical coupling path, preventing the optical coupling path from shifting due to mechanical forces and reducing optical coupling efficiency.

[0077] In the embodiment shown in Figure 2, the projections of the light source 60 and the carrier surface do not overlap on a plane parallel to the carrier surface. For example, the light source 60 can be a laser chip. Since the laser chip is thinner than the photonic integrated circuit chip 40, if the laser chip is directly mounted on the first surface of the second substrate 20, the light signal emitted by the laser chip is difficult to couple to the optical port of the photonic integrated circuit chip 40. Therefore, the mounting position of the laser chip is adjusted by the carrier plate 61 so that the light signal emitted by the laser chip can enter the optical port through a shorter light transmission path.

[0078] In the embodiment shown in Figure 2, a lens 72 and an isolator 71 are arranged sequentially in the optical coupling path between the light source 60 and the photonic integrated circuit chip 40. The lens 72 and the isolator 71 are fixed to the first surface of the second substrate 20. On a plane parallel to the bearing surface, the projections of the lens 72 and the bearing surface do not overlap. The projection of the isolator 71 and the bearing surface do not overlap. The optical signal is emitted from the light source 60, passes through the lens 72 and the isolator 71 in sequence, and then enters the optical port. Both the lens 72 and the isolator 71 are optical elements. In the optical coupling path, the lens 72 is used to focus the diverging optical signal, thereby improving the optical coupling efficiency. The isolator 71 is used to prevent the reflected light from propagating backward, thereby avoiding interference from the reflected light to the light source 60 or other optical elements.

[0079] In some embodiments, the wiring structure 21 includes a multilayer conductive layer located inside the second substrate 20, and also includes conductive layers located on the first surface and the second surface of the second substrate 20.

[0080] Furthermore, the design of the second substrate 20 extending beyond the first substrate 10 allows the pick-and-place machine and coupling stage to be easily observed and packaged using a top-view camera.

[0081] Figure 3 shows a schematic diagram of a packaging structure according to another embodiment of this application. In this embodiment, the first substrate 10 further includes a first opening 11, and the projection of the optical port and the first opening 11 overlaps on a plane parallel to the bearing surface. The first opening 11 penetrates the first substrate 10, and the optical port and light source 60 are exposed through the first opening 11. The light source 60 and optical elements can be partially accommodated in the first opening 11. Compared with the embodiment shown in Figure 2, in this embodiment, since the photonic integrated circuit chip 40 does not need to extend beyond the edge of the first substrate 10, the mounting position of the photonic integrated circuit chip 40 on the first substrate 10 can be set more flexibly. The light source 60 and the optical port are located inside the edge of the first substrate 10 and are protected by the first substrate 10, avoiding the problem that the light source 60 and the optical port are more easily damaged without protection when they are located outside the edge of the first substrate 10.

[0082] In the embodiment shown in Figure 3, a photonic integrated circuit chip 40, a light source 60, and a second connecting line 52 are sequentially arranged horizontally on the first surface of the second substrate 20. A flexible circuit board 51 is disposed on the side of the second substrate 20 near the second connecting line 52 and away from the photonic integrated circuit chip 40. In the embodiment of Figure 3, by disposing of the flexible circuit board 51 on the side of the second substrate 20 near the second connecting line 52 and away from the photonic integrated circuit chip 40, the metal wires on the second surface of the second substrate 20 are shorter than in the embodiment of Figure 2. This results in a shorter electrical connection path between the light source 60 and the first substrate 10, enhancing the reliability of the packaging structure and reducing production costs.

[0083] In addition, the first substrate 10 includes a first opening 11, which allows the pick-and-place machine and coupling stage to be easily observed and packaged using a top-view camera.

[0084] Figure 4 shows a schematic diagram of a packaging structure according to another embodiment of this application, wherein the first end of the flexible circuit board 51 is electrically connected to the bearing surface of the first substrate 10 through a third surface, and the second end of the flexible circuit board 51 is electrically connected to the first surface of the second substrate 20 through a fourth surface. This allows the two ends of the flexible circuit board 51 to connect the two opposing surfaces (facing each other) of the first substrate 10 and the second substrate 20, avoiding the difficulties associated with wire bonding between these two opposing surfaces.

[0085] In the embodiment shown in Figure 4, by setting vias and layer-change wiring inside the flexible circuit board 51, the pads at the first end of the flexible circuit board 51 are disposed on the third surface, and the pads at the second end of the flexible circuit board 51 are disposed on the fourth surface. The wiring structure 21 includes a metal conductor layer located on the first surface of the second substrate 20. The second end of the flexible circuit board 51 is electrically connected to the second end of the second connecting line 52 through the metal conductor layer disposed on the first surface of the second substrate 20. Compared with the embodiment shown in Figure 2, in this embodiment, the flexible circuit board 51 is directly electrically connected to the second connecting line 52 through the metal conductors on the first surface of the second substrate 20. The wiring structure 21 does not need to penetrate the conductive holes of the second substrate 20, which optimizes the manufacturing process of the second substrate 20 and reduces manufacturing costs.

[0086] Figure 5 shows a schematic diagram of a packaging structure according to another embodiment of this application. In this embodiment, the first substrate 10 further includes a first opening 11, on a plane parallel to the bearing surface, the projection of the optical port overlaps with the first opening 11. The first opening 11 penetrates the first substrate 10, exposing the optical port and light source 60, etc., through the first opening 11. The light source 60 and optical elements can be partially housed within the first opening 11, but the maximum height of the light source 60 and optical elements should be less than the distance from the first surface of the second substrate 20 to the back surface (opposite surface of the bearing surface) of the first substrate 10. Compared to the embodiment shown in Figure 4, in this embodiment, since the photonic integrated circuit chip 40 does not need to extend beyond the edge of the first substrate 10, the mounting position of the photonic integrated circuit chip 40 on the first substrate 10 can be set more flexibly. The light source 60 and optical port are located within the edge of the first substrate 10 and are protected by the first substrate 10, avoiding the problem that the light source 60 and optical port are more easily damaged without protection when located outside the edge of the first substrate 10.

[0087] In the embodiment shown in Figure 5, a photonic integrated circuit chip 40, a light source 60, and a second connecting line 52 are sequentially arranged horizontally on the second surface of the second substrate 20. A flexible circuit board 51 is disposed on the side of the second substrate 20 near the second connecting line 52 and away from the photonic integrated circuit chip 40. In the embodiment shown in Figure 4, the second substrate 20 extends beyond the edge of the first substrate 10. Therefore, the flexible circuit board 51 is disposed on the side of the second substrate 20 near the first substrate 10, and the second connecting line 52 is disposed on the side of the second substrate 20 away from the first substrate 10. Since the flexible circuit board 51 and the second connecting line 52 are far apart, they need to be connected via a relatively long metal wire on the second surface of the second substrate 20. In the embodiment of FIG5, the flexible circuit board 51 is disposed on the side of the second substrate 20 that is close to the second connection line 52 and away from the photonic integrated circuit chip 40. When disposed on the side that is close to the second connection line 52 and away from the photonic integrated circuit chip 40, the metal wires on the first surface of the second substrate 20 are shorter than those in the embodiment of FIG4, thereby achieving a shorter electrical connection path between the light source 60 and the first substrate 10, enhancing the reliability of the packaging structure and reducing production costs.

[0088] Figure 6 shows a schematic diagram of a packaging structure according to another embodiment of this application. The first end of the flexible circuit board 51 is electrically connected to the bearing surface of the first substrate 10 via a third surface, and the second end of the flexible circuit board 51 is electrically connected to the second end of the second connecting line 52 via a fourth surface. That is, the second substrate 20 may not include the wiring structure 21 (not shown in Figure 6), and the second end of the flexible circuit board 51 is electrically connected to the second end of the second connecting line 52 via a pad disposed on the fourth surface. In some embodiments, the second end of the flexible circuit board 51 is fixed to the first surface of the second substrate 20 via the third surface. As shown in Figure 6, the first end of the flexible circuit board 51 can be fixed to the bearing surface of the first substrate 10 via the third surface. The flexible circuit board 51 extends from the first end, and at least a portion of it is disposed above the second surface of the second substrate 20 after extension. The length of the flexible circuit board 51 in the extension direction is greater than the length of the second substrate 20 in that direction. The portion extending out of the second substrate 20 bends downward and adheres to the first surface of the second substrate 20 via the third surface of the second end, exposing the opposite fourth surface for electrical connection with the second connecting line 52. In some embodiments, the portion of the flexible circuit board 51 located on the second surface of the second substrate 20 can be bonded and fixed to the second surface.

[0089] Compared to the embodiment shown in Figures 2-5, directly connecting the second end of the flexible circuit board 51 to the second end of the second connecting line 52 eliminates the process of manufacturing wiring structures on the second substrate, thus reducing production costs.

[0090] Figure 7 shows a schematic diagram of a packaging structure according to another embodiment of this application. The first end of the flexible circuit board 51 is electrically connected to the bottom surface of the first substrate 10 via a fourth surface. The second end of the flexible circuit board 51 is bent upwards so that the third surface of the second end faces the first surface of the second substrate 20 and is adhered to the first surface of the second substrate 20. The fourth surface of the second end of the flexible circuit board 51 is exposed and electrically connected to the second connecting line 52. The portion between the first and second ends of the flexible circuit board is suspended in the space below the second substrate 20. Exemplarily, the electrical connection between the bearing surface and the bottom surface of the first substrate 10 can be achieved through conductive vias and wiring layers inside the first substrate 10. In this embodiment, since the first end of the flexible circuit board 51 is electrically connected to the bottom surface of the first substrate 10, it does not need to bypass the second surface of the second substrate 20. The flexible circuit board 51 can be housed in the space below the second substrate 20. Compared to the embodiment shown in Figure 6, the length of the flexible circuit board 51 can be shorter, reducing circuit loss.

[0091] Figure 8 shows a schematic diagram of a packaging structure according to another embodiment of this application. The first substrate 10 further includes a first opening 11, and the projection of the optical port and the first opening 11 overlaps on a plane parallel to the bearing surface. The first opening 11 penetrates the first substrate 10, and the optical port and light source 60 are exposed through the first opening 11. The light source 60 and optical elements can be partially accommodated in the first opening 11. The first end of the flexible circuit board 51 is electrically connected to the bearing surface of the first substrate 10 through a fourth surface. In the embodiment shown in Figure 8, the photonic integrated circuit chip 40, the light source 60, and the second connecting line 52 are sequentially arranged in a horizontal direction on the second surface of the second substrate 20. The flexible circuit board 51 is disposed on the side of the second substrate 20 near the second connecting line 52 and away from the photonic integrated circuit chip 40. In Figure 8, this allows the two ends of the flexible circuit board 51 to connect the two opposing surfaces (two surfaces facing each other) of the first substrate 10 and the second substrate 20, avoiding the difficulties that exist when wire bonding these two opposing surfaces. Furthermore, in the embodiment of FIG8, the flexible circuit board 51 is disposed on the side of the second substrate 20 that is close to the second connection line 52 and away from the photonic integrated circuit chip 40. When disposed on the side that is close to the second connection line 52 and away from the photonic integrated circuit chip 40, the length of the flexible circuit board 51 is shorter than that in the embodiment of FIG6, thereby realizing a shorter electrical connection path between the light source 60 and the first substrate 10, enhancing the reliability of the packaging structure and reducing production costs.

[0092] This application also provides a method for manufacturing a packaging structure, which includes steps 101-105. The packaging structure described in the embodiments of the present invention can be manufactured using this manufacturing method.

[0093] Step 101: Fix the electronic integrated circuit chip 30 and the photonic integrated circuit chip 40 together.

[0094] Step 102: Provide a first substrate 10, the first substrate 10 having a bearing surface; fix the combination of electronic integrated circuit chip 30 and photonic integrated circuit chip 40 to the first substrate 10, wherein the electronic integrated circuit chip 30 is mounted to the bearing surface of the first substrate 10.

[0095] Step 103: Provide a second substrate 20, which has a first surface and an opposing second surface; fix the photonic integrated circuit chip 40 and the second substrate 20 together so that the first surface of the second substrate 20 is close to the bearing surface of the first substrate 10.

[0096] Step 104: Fix the first end and the second end of the flexible circuit board 51 to the first substrate 10 and the second substrate 20 respectively;

[0097] Step 105: Mount the light source 60 on the first surface of the second substrate 20 to form an optical coupling path between the light source 60 and the photonic integrated circuit chip 40.

[0098] In some embodiments, the method includes: after fixing the second end of the flexible circuit board 51 to the second substrate, electrically connecting the light source to the second end of the flexible circuit board 51 by wire bonding.

[0099] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0100] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A packaging structure, characterized in that, It includes: A first substrate, an electronic integrated circuit chip, a photonic integrated circuit chip, and a second substrate are stacked sequentially. The first substrate has a bearing surface and an opposing bottom surface, the electronic integrated circuit chip is disposed on the bearing surface, and the second substrate has a first surface close to the first substrate and a second surface away from the first substrate. A flexible circuit board has a first end and a second end, wherein the first end is electrically connected to the first substrate. A light source is disposed on the third surface of the second substrate, the light source is electrically connected to the second end of the flexible circuit board, and the light source is optically coupled to the photonic integrated circuit chip.

2. The packaging structure as described in claim 1, characterized in that, The flexible circuit board has a third surface and an opposing fourth surface.

3. The packaging structure as described in claim 2, characterized in that, The first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate through a third surface, and the second end of the flexible circuit board is electrically connected to the second surface of the second substrate through a third surface.

4. The packaging structure as described in claim 3, characterized in that, The packaging structure further includes a second connecting line, and the second substrate includes a wiring structure; the second connecting line has a first end and a second end, the first end being electrically connected to the light source, the second end being electrically connected to a first surface of the second substrate, and the second end being electrically connected to the flexible circuit board through the wiring structure of the second substrate; wherein, the light source is electrically connected to the flexible circuit board through the second end of the second connecting line, and is electrically connected to the first substrate via the flexible circuit board.

5. The packaging structure as described in claim 4, characterized in that, The wiring structure includes conductive holes located within the second substrate.

6. The packaging structure as described in claim 5, characterized in that, The second end of the flexible circuit board is electrically connected to the conductive hole through a portion of a wiring structure disposed on the second surface of the second substrate, and is electrically connected to the second end of the second connecting line via the conductive hole.

7. The packaging structure as described in claim 2, characterized in that, The first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate through a third surface, and the second end of the flexible circuit board is electrically connected to the first surface of the second substrate through a fourth surface.

8. The packaging structure as described in claim 7, characterized in that, The packaging structure further includes a second connecting line, and the second substrate includes a wiring structure; the second connecting line has a first end and a second end, the first end being electrically connected to the light source, the second end being electrically connected to a first surface of the second substrate, and the second end being electrically connected to the flexible circuit board through the wiring structure of the second substrate; wherein, the light source is electrically connected to the flexible circuit board through the second end of the second connecting line, and is electrically connected to the first substrate via the flexible circuit board.

9. The packaging structure as described in claim 8, characterized in that, The wiring structure includes a metal conductor layer located on a first surface of the second substrate.

10. The packaging structure as described in claim 9, characterized in that, The second end of the flexible circuit board is electrically connected to the second end of the second connecting line through a metal wire layer disposed on the first surface of the second substrate.

11. The packaging structure as described in claim 2, characterized in that, The encapsulation structure further includes a second connecting line, which has a first end and a second end, the first end of which is electrically connected to the light source.

12. The packaging structure as described in claim 11, characterized in that, The second end of the flexible circuit board is electrically connected to the second end of the second connecting line via the fourth surface.

13. The packaging structure as described in claim 12, characterized in that, The first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate through a third surface.

14. The packaging structure as described in claim 12, characterized in that, The first end of the flexible circuit board is electrically connected to the bottom surface of the first substrate via a fourth surface.

15. The packaging structure as described in claim 12, characterized in that, The first end of the flexible circuit board is electrically connected to the bearing surface of the first substrate via a fourth surface.

16. The packaging structure as described in claim 12, characterized in that, The second end of the flexible circuit board is fixed to the first surface of the second substrate via a third surface.

17. The packaging structure as described in any one of claims 4, 8, or 11, characterized in that, The second connecting line is a gold wire.

18. The packaging structure as described in claim 1, characterized in that, The photonic integrated circuit chip includes an optical port, and the projection of the optical port onto the support surface does not overlap on a plane parallel to the support surface.

19. The packaging structure as described in claim 18, characterized in that, The optical port extends beyond the edge of the bearing surface.

20. The packaging structure as described in claim 18, characterized in that, The first substrate includes a first opening, and the projection of the optical port on the plane parallel to the bearing surface overlaps with the first opening.

21. The packaging structure as described in claim 1, characterized in that, The photonic integrated circuit chip includes an optical port, which is an edge coupler.

22. The packaging structure as described in claim 1, characterized in that, On a plane parallel to the bearing surface, the projection of the light source onto the bearing surface does not overlap.

23. The packaging structure as described in claim 1, characterized in that, Also includes: A lens and an isolator are arranged sequentially in the optical coupling path between the light source and the photonic integrated circuit chip; The lens and the isolator are fixed to the first surface of the second substrate.

24. The packaging structure as described in claim 23, characterized in that, On a plane parallel to the bearing surface, the projection of the lens onto the bearing surface does not overlap, and the projection of the isolator onto the bearing surface does not overlap.

25. The packaging structure as described in claim 1, characterized in that, The first substrate includes a printed circuit board or an organic substrate.

26. The packaging structure as described in claim 1, characterized in that, The second substrate includes a rigid substrate.

27. A method for manufacturing a packaging structure, characterized in that, include: The electronic integrated circuit chip and the photonic integrated circuit chip are fixedly connected; A first substrate is provided, the first substrate having a bearing surface; the combination of the electronic integrated circuit chip and the photonic integrated circuit chip is fixedly connected to the first substrate, wherein the electronic integrated circuit chip is mounted to the bearing surface of the first substrate; A second substrate is provided, the second substrate having a first surface and an opposing second surface; The photonic integrated circuit chip and the second substrate are fixedly connected so that the first surface of the second substrate is close to the bearing surface of the first substrate; The first end and the second end of the flexible circuit board are respectively fixed to the first substrate and the second substrate; as well as The light source is mounted on the first surface of the second substrate to form an optical coupling path between the light source and the photonic integrated circuit chip.

28. The manufacturing method according to claim 27, characterized in that, Also includes: After fixing the second end of the flexible circuit board to the second substrate, the light source is electrically connected to the second end of the flexible circuit board by wire bonding.

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