A photoelectric hybrid packaging structure

Abstract

The present invention discloses an optoelectronic hybrid packaging structure, comprising: an FA module, an LGA connector arranged on a PCB board, an adapter board located on the pins of the LGA connector, a silicon photonic chip located on the adapter board and electrically connected to the pins through the adapter board, a side edge of an upper cover plate of the silicon photonic chip close to the LGA connector, an opening corresponding to the position of the silicon photonic chip is arranged on the edge, and the FA module is installed at a position where optical coupling with the silicon photonic chip can be achieved through the opening. The present invention uses an LGA connector for optoelectronic hybrid packaging, and makes the FA module, the LGA connector and the PCB board into a whole, so that the optically coupled FA module becomes a coupling device independent of the silicon photonic chip, thereby realizing the versatility and reconfigurability of optoelectronic hybrid packaging of silicon photonic chips.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to an optoelectronic hybrid packaging structure. Background Art

[0002] The current mature electrical packaging of silicon photonic chips is mainly connected to the PCB board through wire bonding for lead-out. This method is limited by the PCB board process and wire bonding process and has certain limitations. First, the number of pads that can be led out per unit area of ​​the silicon photonic chip is limited because the number of layers and distance of wire bonding are limited; second, the size of the packaging module is large and the degree of integration is not high; third, the stability will also deteriorate as the number of wire bonding lines increases.

[0003] In order to solve the limitations of wire bonding packaging pad quantity and loss, the industry has begun to use the form of value ball flip chip bonding for integrated packaging, such as Figure 1 This solves the limitation of wire bonding very well, but this method requires two ball bonding and two flip-chip bonding, which is very expensive. At the same time, it is only applicable to some specific silicon photonic chips, and its versatility and reconfigurability are also poor.

[0004] For the optical packaging method of silicon photonic chips, FA (Fiber Array) packaging is now commonly used. The specific packaging process is to first use FA to align the optical coupling device (end face, grating, etc.), then use the light source and optical power meter to obtain the state of minimum coupling, and then use glue to cure to obtain the final packaging result. The advantages of this packaging method are that it is simple and easy to use. However, it also has its limitations. First, each piece of package needs to be actively packaged, which is time-consuming; secondly, after the optical coupling is completed, glue curing is required, and its versatility and reconfigurability are poor.

[0005] In summary, the existing conventional optoelectronic hybrid packaging mode of silicon photonic chips, whether electrical packaging or optical packaging, for different silicon photonic chips, first designs different substrate structures, PCB board structures, FA installation positions and fixing structures, etc. according to the number and position of PADs of silicon photonic chips, the number and position of optical ports, and the final packaging requirements, and then performs structural assembly, electrical packaging, and finally optical packaging. This mode is relatively complex, and the final optical packaging is time-consuming, with poor versatility and reconfigurability. It completely limits the efficiency of optoelectronic hybrid packaging of silicon photonic chips. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides an optoelectronic hybrid packaging structure with good versatility and reconfigurability.

[0007] A photoelectric hybrid packaging structure comprises: an FA module, an LGA connector arranged on a PCB board, an adapter board located on the pins of the LGA connector, a silicon photonic chip located on the adapter board and electrically connected to the pins through the adapter board, the silicon photonic chip being close to a side edge of an upper cover plate of the LGA connector, an opening corresponding to the position of the silicon photonic chip being provided on the edge, the FA module being installed at a position where optical coupling with the silicon photonic chip can be achieved through the opening, and the FA module being installed on the PCB board through a mounting bracket.

[0008] As a preferred solution, the light-emitting surface of the FA module extends into an opening of an upper cover plate of the LGA connector.

[0009] As a preferred solution, a lens is further installed between the silicon photonic chip and the FA module.

[0010] As a preferred solution, the lens is mounted on the PCB board via a mounting bracket.

[0011] As a preferred solution, the mounting bracket includes a stage for supporting the FA module and the lens, a clamping plate for fixing to the PCB board, and a support column arranged on the clamping plate for supporting the stage.

[0012] As a preferred solution, the edge of the upper cover plate is bent upward to form the opening.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. By using the LGA connector for optoelectronic hybrid packaging and making the FA module, LGA connector and PCB board into a whole, the optically coupled FA module becomes a coupling device independent of the silicon photonic chip, thus realizing the versatility and reconfigurability of the optoelectronic hybrid packaging of the silicon photonic chip;

[0015] 2. The FA module is supported and fixed by providing an easily disassembled and installed mounting bracket, the mounting bracket has a simple structure and convenient packaging, and can effectively improve the efficiency of optoelectronic hybrid packaging;

[0016] 3. By optimizing the structure of the upper cover plate, the edge of the upper cover plate is formed into an opening in an upwardly curved manner. The structure is simple, easy to implement, and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the structure of the installation state of the LGA connector in the prior art;

[0019] Figure 2 It is a structural schematic diagram of the FA module in the prior art;

[0020] Figure 3 It is an overall schematic diagram of an optoelectronic hybrid packaging structure of the present invention;

[0021] Figure 4 A schematic diagram of a mounting bracket structure of an optoelectronic hybrid packaging structure of the present invention;

[0022] Figure 5 The figure is a comparative schematic diagram of the edge shape of the upper cover plate of an optoelectronic hybrid packaging structure of the present invention.

[0023] Among them: 1. FA module; 2. PCB board; 3. adapter board; 4. silicon photonic chip; 5. upper cover plate; 6. BGA; 7. LGA interface; 8. pins; 9. EIC chip; 10. lens; 11 mounting bracket; 12 stage; 13 plywood; 14 support column; 15 screws. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] A photoelectric hybrid packaging structure, such as Figure 3As shown, it includes: an FA module 1, an LGA connector arranged on a PCB board 2, an adapter board 3 located on the pins of the LGA connector, a silicon photonic chip 4 located on the adapter board 3 and electrically connected to the pins through the adapter board 3, the silicon photonic chip 4 is close to a side edge of an upper cover plate 5 of the LGA connector, an opening corresponding to the position of the silicon photonic chip 4 is provided on the edge, and the FA module 1 is fixedly installed in a position where optical coupling with the silicon photonic chip 4 can be achieved through the opening.

[0027] The LGA connector (Land Grid Array Connector) is a relatively mature mass-produced product in the prior art, and the number of its pins ranges from several hundred to several thousand. The lower surface of the adapter board 3 can be designed to match the LGA connector, and the upper surface thereof is designed with a corresponding pad coupling silicon photonic chip pad; the maximum number of silicon photonic chip pads that can be packaged is several thousand, which can fully meet the universal application of the optoelectronic hybrid packaging structure. The adapter board can be an LTCC adapter board.

[0028] like Figure 1 As shown, the existing LGA connector includes an LGA interface (LGA Socket) 7 with pins 8 electrically connected to a PCB board 2 through a BGA (Ball Grid Array) 6, and the pins 8 are connected to a CPU module (including an LTCC adapter board 3 and an EIC chip 9). It also includes an upper cover plate 5 for pressing the CPU module so that the pad and the connector pins 8 have a stable connection.

[0029] like Figure 2 As shown, the FA module 1 includes a FA lower cover plate, a FA upper cover plate and a FA optical core, wherein the height of the FA upper cover plate is H1, the height of the FA lower cover plate is H2, and the width of the FA module is W.

[0030] like Figure 3 As shown, the installation position of the FA module 1 corresponds to the end face coupling optical port of the silicon photonic chip 4, and the connection line between the two passes through the opening on the edge. Since the silicon photonic chip 4 is located close to the edge of the upper cover 5 (i.e., within the range of the upper cover pressing), the design of the opening can allow the silicon photonic chip 4 and the FA module 1 to achieve optical coupling on the one hand, and can also prevent the upper cover 5 from pressing on the silicon photonic chip 4 on the other hand; in other words, the upper cover 5 of the LGA connector has a design that avoids the position where the FA module 1 and the silicon photonic chip 4 are optically coupled.

[0031] Furthermore, if Figure 3As shown, since the silicon photonic chip 4 is located on the inner side of the upper cover plate 5, in order to better couple with the silicon photonic chip 4, the light-emitting surface of the FA module 1 can be set to extend into the opening of the upper cover plate 5 of the LGA connector. In other words, in this case, the size of the opening should be at least slightly larger than the size of one side of the light-emitting surface of the FA module 1.

[0032] In this embodiment, the LGA connector is applied to the silicon photonic chip package, and the adapter board and the LGA connector are used in combination. The silicon photonic chip is set on the adapter board, and an opening is set on the edge of the upper cover plate of the LGA connector, so that the coupling position of the FA module can be accurately set. After the FA module is fixed at the coupling position, the silicon photonic module in the LGA connector (which is composed of the silicon photonic chip flip-chip soldered to the adapter board) can be removed, so that the FA module, the LGA connector and the PCB board become a whole, so that the optically coupled FA module becomes a coupling device independent of the silicon photonic chip, and the reconfigurability of the optoelectronic hybrid package of the silicon photonic chip is realized.

[0033] In one embodiment, Figure 3 As shown, a lens 10 is further installed between the silicon photonic chip 4 and the FA module 1 .

[0034] In order to increase the tolerance of optical coupling, in this embodiment, a FA module 1 with a larger pattern spot (for example, a size of 10 um) can be selected, and a lens 10 is installed at the light outlet of the FA module 1 to further increase the tolerance of optical coupling.

[0035] In one embodiment, Figure 4 As shown, the FA module 1, or the FA module 1 and the lens 10, can be mounted on the PCB board 2 via a mounting bracket 11. Preferably, the mounting bracket includes a stage 12 for supporting the FA module 1 and the lens 10, a clamping plate 13 for fixing to the PCB board 2, and a support column 14 arranged on the clamping plate 13 for supporting the stage 12.

[0036] The clamping plates 13 can be fixedly clamped on the upper and lower sides of the PCB board 2, and the clamping plates 13 can be fixedly connected by screws 15 passing through the through holes on the PCB board 2. The FA module 1 and the lens 10 are placed on the upper surface of the stage 12 to couple the optical signal output from the end face of the silicon photonic chip 4. The FA module 1 and the lens 10 can be respectively bonded to the stage 12 by glue.

[0037] In this embodiment, a mounting bracket is designed for optical packaging of silicon photonic chips, and the mounting bracket is fixed to the PCB board by screws and clamps. In the mounting bracket, the screws and clamps play a fixing role, ensuring that the mounting bracket is in a certain relative position on the horizontal plane of the PCB board. The function of the support column is to support the stage and ensure that the upper surface of the stage is at a relatively stable height. Specifically, Figure 4 As shown, considering that the thickness of the LGA connector is certain, the adapter board is designed to a certain size, and the size of the silicon photonic chip and the implant ball is certain, the distance H3 from the upper surface of the silicon photonic chip to the PCB board is completely within a controllable range. Therefore, when designing the mounting bracket, as long as the heights of H4 and H3 are guaranteed to be consistent and the end face of the silicon photonic chip is determined to be at the edge of the chip, the optical coupling efficiency between them can be fully within the required range. Since the horizontal relative position of the entire mounting bracket relative to the PCB board is stable, and the electrical packaging and optical packaging are independent of the silicon photonic chip, the versatility, reconfigurability and subsequent loading and unloading flexibility of the optoelectronic hybrid packaging structure can be guaranteed.

[0038] In this embodiment, the specific installation method is: first install the silicon photonic module (composed of a silicon photonic chip flip-chip soldered to an adapter board) on the LGA connector, then move the FA module and the lens on the stage for optical coupling, and when the optical coupling is optimal, glue is applied to fix the FA and the lens (the side of the lens that is close to the silicon photonic chip cannot be glued to ensure the independence of the two); then open the upper cover of the LGA connector and remove the silicon photonic module, thus obtaining a universal device for flip-chip optoelectronic hybrid packaging of silicon photonic chips based on the LGA connector. This realizes the reconfigurability of the optoelectronic hybrid packaging of silicon photonic chips.

[0039] In one embodiment, Figure 5 As shown, the edge of the upper cover plate 5 is bent upward to form the opening.

[0040] In this embodiment, considering that the traditional LGA connector is designed for packaging electronic chips (CPU) and does not reserve an installation position for the FA module, in order to ensure the packaging space of the FA module, this embodiment optimizes the upper cover of the LGA connector to make it compatible with the optical packaging of the silicon photonic chip. Figure 5In the figure, the left figure is a schematic diagram of the structure of the ILM upper cover in the prior art, the middle figure is a side view of the ILM upper cover in the prior art, and the right figure is a schematic diagram of the structure of the upper cover bending upward to form the opening in this embodiment. In order to reserve space for FA packaging, while also ensuring the integrity of the upper cover and the required pressing force for the connection between the adapter board and the LGA connector, the edge of the upper cover of the LGA connector in this embodiment is designed to bend upward to form an arc to reserve a space for the FA module. In particular, the arc height of the upper cover of the LGA connector is greater than the thickness H1 of the FA upper cover, and the width is greater than the width W of the FA, to ensure that the FA module has sufficient installation space.

[0041] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An optoelectronic hybrid packaging structure, characterized in that: include: An FA module, an LGA connector arranged on a PCB board, an adapter board located on the pins of the LGA connector, a silicon photonic chip located on the adapter board and electrically connected to the pins through the adapter board, the silicon photonic chip is close to a side edge of an upper cover plate of the LGA connector, an opening corresponding to the position of the silicon photonic chip is provided on the edge, the FA module is installed at a position where optical coupling with the silicon photonic chip can be achieved through the opening, and the FA module is installed on a PCB board through a mounting bracket; the mounting method of the silicon photonic chip is as follows: when the optical coupling is optimal, the FA module is fixed by glue, and the silicon photonic chip is removed, thereby obtaining a universal device for flip-chip optoelectronic hybrid packaging of silicon photonic chips based on an LGA connector; The FA module includes a FA lower cover plate, a FA upper cover plate and a FA optical core, the height of the FA upper cover plate is H1, and the width of the FA module is W; The edge of the upper cover plate of the LGA connector is bent upward to form an opening; The arc height of the upper cover plate of the LGA connector is greater than the thickness H1 of the upper cover plate of the FA, and the width is greater than the width W of the FA.

2. The optoelectronic hybrid packaging structure according to claim 1, characterized in that: The light-emitting surface of the FA module extends into the opening of the upper cover plate of the LGA connector.

3. The optoelectronic hybrid packaging structure according to claim 1 or 2, characterized in that: A lens is also installed between the silicon photonic chip and the FA module.

4. The optoelectronic hybrid packaging structure according to claim 3, characterized in that: The lens is mounted on the PCB board through a mounting bracket.

5. The optoelectronic hybrid packaging structure according to claim 4, characterized in that: The mounting bracket includes a stage for supporting the FA module and the lens, a clamping plate for fixing to the PCB board, and a supporting column arranged on the clamping plate for supporting the stage.

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