A microsystem integration method for optical modules

Abstract

This invention provides a microsystem integration method for optical modules, comprising, from top to bottom, an upper cover, an optical module PCBA, a lower shell, a microsystem packaging substrate, and a connecting piece embedded in the lower shell. The upper cover is detachably fixed to the lower shell, the optical module PCBA is detachably connected to the lower shell, and the bottom of the optical module PCBA and the connecting piece are elastically interconnected via an LGA array. The lower shell is fixed to the microsystem packaging substrate. This invention enables the optical module and the microsystem packaging substrate to be connected via the elastic connecting piece, achieving a plug-in connection between the optical module and the microsystem packaging substrate, improving the convenience of microsystem maintenance, and providing a solution for adapting to reflow soldering in optoelectronic integrated microsystem applications. Through alignment design, this invention achieves a horizontal and vertical alignment accuracy of 0.2mm, meeting the stable electrical connection requirements of high-density connecting pieces. The connecting piece used in this invention is a single-sided BGA injection-molded device with single-sided elastic contacts, with 100 contacts, meeting the requirements for 30GHz signal transmission.

Description

Technical Field

[0001] This invention relates to the field of electrical component technology, and more specifically to a microsystem integration method for optical modules. Background Technology

[0002] Optoelectronic integrated microsystems typically use soldering to integrate optical modules with the microsystem packaging substrate. Because optoelectronic packaging materials are not heat-resistant, traditional reflow soldering processes are not suitable for microsystem products in applications. In addition, damage to the optoelectronic components can lead to the failure of the entire microsystem, making local repairs inconvenient.

[0003] Therefore, a microsystem integration method that facilitates local maintenance is needed. Summary of the Invention

[0004] This invention aims to solve the problem of partial maintenance of microsystems by providing a microsystem integration method for optical modules. The method connects the optical module and the microsystem packaging substrate through elastic connecting pieces, realizing a plug-in connection between the optical module and the microsystem packaging substrate, improving the convenience of microsystem maintenance, and providing a solution for adapting to reflow soldering in the application of optoelectronic integrated microsystems. It can also meet the requirements of stable electrical connection of high-density connecting pieces and 30GHz signal transmission.

[0005] This invention provides a microsystem integration method for optical modules. The microsystem for the optical module includes, from top to bottom, an upper cover, an optical module PCBA, a lower shell, a microsystem packaging substrate, and a connecting piece embedded in the lower shell. The upper cover is detachably fixed to the lower shell, the optical module PCBA is detachably connected to the lower shell, the bottom of the optical module PCBA and the connecting piece are elastically interconnected through an LGA array, and the lower shell is fixed on the microsystem packaging substrate.

[0006] The optical module PCBA includes a printed circuit board body, communication components interconnected with the printed circuit board body, and locating pin mounting holes provided on the printed circuit board body;

[0007] The lower shell includes a lower shell body fixed on a microsystem packaging substrate, a connecting piece mounting hole fixed in the lower shell body and a positioning pin on the upper surface of the lower shell body corresponding to the position of the positioning pin mounting hole.

[0008] The integration method for microsystems of optical modules includes the following steps:

[0009] S1. Solder the connector to the microsystem packaging substrate using reflow soldering;

[0010] S2. The lower shell is passed through the connecting piece and fixed on the microsystem packaging substrate. The mounting hole of the connecting piece and the connecting piece are tightly fitted.

[0011] S3. Insert the optical module PCBA, so that the positioning pin enters the mounting hole and fixes the optical module PCBA to the lower shell.

[0012] S4. Snap the top cover on and tighten it with screws to complete the integration of the microsystem for the optical module.

[0013] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, includes notches at the four corners of the printed circuit board body and bosses at the four corners of the lower shell body, with the notches corresponding to the shapes of the bosses.

[0014] In step S3, after the optical module PCBA is inserted, the notch and the boss are fixed.

[0015] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, further includes screw mounting holes provided on the boss in the lower housing;

[0016] The top cover includes a top cover body and top cover screw mounting holes located at the four corners of the top cover body;

[0017] In step S4, the top cover is fastened, and the screws are passed through the screw mounting holes on the top cover and the screw mounting holes in sequence to press the top cover into the optical module PCBA and fix it to the lower shell.

[0018] In a preferred embodiment of the microsystem integration method for optical modules described in this invention, the boss is a fan-shaped protrusion with its arc surface facing the center of the lower shell body, and the notch is a fan-shaped notch with its arc surface facing the outside of the printed circuit board body.

[0019] The length and width of the top cover, the printed circuit board body, and the bottom shell body are all the same.

[0020] In the microsystem integration method for optical modules described in this invention, as a preferred embodiment, the boss and the notch are tightly fitted with a positive tolerance of <0.01mm.

[0021] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, involves both the mounting holes and the connecting pieces being square and corresponding in size, forming a tight fit after assembly, with a positive tolerance of <0.01mm for the mounting holes and the connecting pieces.

[0022] The top cover and the lower shell are made of nickel-plated copper.

[0023] The lower shell is fixed to the microsystem packaging substrate with adhesive.

[0024] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, includes a first LGA array on the upper part of the connecting piece and a BGA array on the lower part. The optical module PCBA also includes a second LGA array disposed at the bottom of the printed circuit board body. The first LGA array and the second LGA array are arranged in the same way and form elastic contact points after assembly. The connecting piece is interconnected with the microsystem packaging substrate through the BGA array.

[0025] The connecting piece is made of plastic produced by injection molding;

[0026] The first LGA array meets the 30GHz signal transmission requirements.

[0027] In the microsystem integration method for optical modules described in this invention, the printed circuit board body is preferably made of high-frequency PCB material.

[0028] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, has a pin pitch of 0.8 mm for the optical module PCBA, and the communication components include optical devices and optoelectronic devices.

[0029] The microsystem integration method for optical modules described in this invention, as a preferred embodiment, further includes screw mounting clearance slots at the four corners of the cover body and printed circuit board clearance slots on the back of the cover body, the printed circuit board clearance slots being used to avoid communication components.

[0030] This invention discloses a microsystem integration method for optical modules. The microsystem packaging substrate carries a heat source electrical chip (20W) and the optical module. The optical module PCBA has a temperature resistance of <120℃. Reflow soldering is required in microsystem product applications, with temperatures >180℃. The data rate is 25Gbps / lane; therefore, the electrical connection pin pitch is 0.8mm, requiring a horizontal and vertical alignment accuracy of 0.2mm.

[0031] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a microsystem integration method for optical modules, comprising an upper cover, an optical module PCBA, a lower shell, a connecting piece, a microsystem packaging substrate, solder, and adhesive.

[0032] The top cover is independent of the optical module and is not shared with other parts of the microsystem packaging substrate (5).

[0033] The bottom of the optical module PCBA is an LGA (Grid Array) and has positioning holes.

[0034] The lower shell has upward-facing positioning pins for inserting the optical module PCBA; the lower surface has a dot matrix of bumps that are integrated with the microsystem packaging substrate by adhesive.

[0035] The microsystem package substrate has an array of flexible contacts on top and a BGA array on the bottom, which is integrated with the microsystem package substrate by solder.

[0036] The present invention has the following advantages:

[0037] (1) The present invention designs a microsystem integration method for optical modules, which can realize plug-in connection between optical modules and microsystem packaging substrates, improve the maintenance convenience of microsystems, and provide a solution for adapting optoelectronic integrated microsystems to reflow soldering in applications.

[0038] (2) The present invention achieves a horizontal and vertical alignment accuracy of 0.2mm through alignment design, which satisfies the stable electrical connection of high-density connecting pieces.

[0039] (3) The connecting piece selected in this invention is an injection-molded device with a single-sided BGA single-sided elastic contact, and the number of contacts is 100, which meets the requirements of 30GHz signal transmission. Attached Figure Description

[0040] Figure 1 This is a flowchart of a microsystem integration method for optical modules;

[0041] Figure 2 This is a bottom-shell perspective view of a microsystem integration method for optical modules;

[0042] Figure 3 This is a lower shell side view of a microsystem integration method for optical modules;

[0043] Figure 4 A front perspective view of the top cover of a microsystem integration method for optical modules;

[0044] Figure 5 A three-dimensional view of the top and bottom surfaces of a microsystem integration method for optical modules;

[0045] Figure 6 This is a three-dimensional diagram of an optical module PCBA, representing a microsystem integration method for optical modules.

[0046] Figure label:

[0047] 1. Top cover; 11. Top cover body; 12. Top cover screw mounting hole; 13. Screw mounting clearance groove; 14. Printed circuit board clearance groove; 2. Optical module PCBA; 21. Printed circuit board body; 22. Communication component; 23. Positioning pin mounting hole; 24. Notch; 3. Lower shell; 31. Lower shell body; 32. Connecting piece mounting hole; 33. Positioning pin; 34. Boss; 35. Screw mounting hole; 4. Microsystem packaging substrate; 5. Connecting piece; 51. First LGA array. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1

[0050] like Figures 1-6 As shown, a microsystem integration method for an optical module is described. The microsystem for the optical module includes, from top to bottom, an upper cover 1, an optical module PCBA2, a lower shell 3, a microsystem packaging substrate 4, and a connecting piece 5 embedded in the lower shell 3. The upper cover 1 is detachably fixed to the lower shell 3, the optical module PCBA2 is detachably connected to the lower shell 3, the bottom of the optical module PCBA2 and the connecting piece 5 are elastically interconnected through an LGA array, and the lower shell 3 is fixed on the microsystem packaging substrate 4.

[0051] like Figures 4-5 As shown, the upper cover 1 includes an upper cover body 11, upper cover screw mounting holes 12 provided at the four corners of the upper cover body 11, screw mounting clearance grooves 13 provided at the four corners of the upper cover body 11, and printed circuit board clearance grooves 14 provided on the back of the upper cover body 11. The printed circuit board clearance grooves 14 are used to avoid communication components 22.

[0052] like Figure 6 As shown, the optical module PCBA2 includes a printed circuit board body 21, a communication component 22 interconnected with the printed circuit board body 21, a positioning pin mounting hole 23 provided on the printed circuit board body 21, and corner notches 24 provided at the four corners of the printed circuit board body 21.

[0053] The printed circuit board body 21 is made of high-frequency PCB board material; the pin center distance of the optical module PCBA2 is 0.8mm; the communication component 22 includes optical devices and optoelectronic devices.

[0054] like Figures 2-3 As shown, the lower shell 3 includes a lower shell body 31 fixed on the microsystem packaging substrate 4, a connecting piece mounting hole 32 fixed in the lower shell body 31 and the connecting piece 5, a positioning pin 33 on the upper surface of the lower shell body 31 corresponding to the position of the positioning pin mounting hole 23, and also includes bosses 34 on the four corners of the lower shell body 31 and screw mounting holes 35 on the bosses 34.

[0055] The shape of the notch 24 corresponds to that of the boss 34;

[0056] The boss 34 is a fan-shaped protrusion with its arc surface facing the center of the lower shell body 31, and the notch 24 is a fan-shaped notch with its arc surface facing the outside of the printed circuit board body 21.

[0057] The length and width of the upper cover 1, the printed circuit board body 21 and the lower shell body 31 are all the same;

[0058] The boss 34 and the notch 24 are tightly fitted, with a positive tolerance of <0.01mm;

[0059] Both the mounting hole 32 and the connecting piece 5 are square and have corresponding dimensions, forming a tight fit after assembly. The positive tolerance of the mounting hole 32 and the connecting piece 5 is <0.01mm.

[0060] The lower shell body 31 is made of copper plated with nickel;

[0061] The lower shell body 31 is fixed to the microsystem packaging substrate 4 by adhesive;

[0062] The upper part of the connecting piece 5 is provided with a first LGA array 51 and the lower part is provided with a BGA array. The optical module PCBA2 also includes a second LGA array provided at the bottom of the printed circuit board body 21. The first LGA array 51 and the second LGA array are arranged in the same way and form elastic contact points after assembly. The connecting piece 5 is interconnected with the microsystem packaging substrate 4 through the BGA array.

[0063] Connecting piece 5 is made of plastic produced by injection molding;

[0064] The integration method for microsystems of optical modules includes the following steps:

[0065] S1. Solder the connecting piece 5 to the microsystem packaging substrate 1 using reflow soldering;

[0066] S2. The lower shell 3 is passed through the connecting piece 5 and fixed on the microsystem packaging substrate 1. The mounting hole 32 of the connecting piece and the connecting piece 5 are tightly fitted.

[0067] S3. Insert the optical module PCBA2, so that the positioning pin 33 enters the mounting hole 23 and fixes the optical module PCBA2 to the lower shell 3. After inserting the optical module PCBA2, the notch 24 is fixed to the boss 34.

[0068] S4. Fasten the top cover 1, and pass the screws through the screw mounting holes 12 and 35 of the top cover in sequence to press the top cover 1 into the optical module PCBA2 and fix it on the lower shell 3. The integration of the microsystem for the optical module is completed.

[0069] In this embodiment, the lower shell body 31 is made of nickel-plated copper, providing a large heat capacity while being resistant to oxidation and corrosion. The rounded corners 34 and the surrounding protrusions 33 are used for positioning and mounting the optical module PCBA, with a positive tolerance of <0.01mm, ensuring a secure hold for the optical module PCBA without the use of screws. The central opening and the connecting piece frame are tightly fitted, with a positive tolerance of <0.01mm.

[0070] In this embodiment, the thickness of the lower shell body 31 is 1.0 mm, the four corner arcs 34 are 1.0 mm higher than the lower shell body 31, the side width of the four corner arcs 34 is 3 mm, the four protrusions 33 are cylinders with a radius of 0.5 mm, and the upper surface is flush with the upper surface of the four corner arcs 34.

[0071] The top cover 11 is made of nickel-plated copper, providing a large heat capacity while being resistant to oxidation and corrosion. The four corners are recessed for screw mounting. The top cover 11 measures 20mm x 20mm, with a total thickness of 5.0mm and a recess depth of 2.5mm to avoid obstructing light paths and optoelectronic devices.

[0072] The optical module PCBA2 is made of high-frequency PCB board, meeting the 25Gbps / lane data rate requirement. It features rounded chamfers 24 at all four corners and through holes 23 on all four sides, aligning with the corresponding structure of the lower shell 3 for secure fixation. The front of this component houses the optical path and optoelectronic devices 22, while the back features an LGA (Grid Array) that contacts the elastic contacts on the top of the connecting piece. The optical module PCBA2 measures 20mm x 20mm.

[0073] Connector 5 is an injection-molded device with a single-sided BGA single-sided elastic contact, with 100 contacts, meeting the requirements for 30GHz signal transmission.

[0074] The method of this invention for microsystem integration of optical modules has the following advantages:

[0075] 1. Maintainability: Since the failure rate of optoelectronic chips is higher than that of electrical chips, they can easily become a bottleneck in the reliability of the entire microsystem. With traditional soldering methods, once the optical module fails, the entire microsystem must be scrapped. Using the method of this invention, the four corner screws can be unscrewed, allowing replacement of the easily damaged optical module, significantly improving the durability of the microsystem and reducing usage and maintenance costs.

[0076] 2. Adaptability to Reflow Soldering: Optical modules use various adhesives, and the high temperatures of soldering can cause malfunctions such as decreased optical collimation. Microsystems commonly require reflow soldering in their applications. Therefore, microsystems integrating optical modules are limited in their application methods because they cannot be reflow soldered. With this invention, the optical module can be removed, reflow soldered to the microsystem and other components, and then reassembled, enabling flexible applications of optoelectronic integrated microsystems.

[0077] After integration, this embodiment achieves an insertion loss of <2dB and a return loss of >10dB for the entire signal link (package substrate-BGA-elastic contact-optical module PCBA) at 30GHz.

[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A microsystem integration method for optical modules, characterized in that: The microsystem for the optical module includes, from top to bottom, an upper cover (1), an optical module PCBA (2), a lower shell (3), a microsystem packaging substrate (4), and a connecting piece (5) embedded in the lower shell (3). The upper cover (1) is detachably fixed to the lower shell (3). The optical module PCBA (2) is detachably connected to the lower shell (3). The bottom of the optical module PCBA (2) and the connecting piece (5) are elastically interconnected through an LGA array. The lower shell (3) is fixed on the microsystem packaging substrate (4). The optical module PCBA (2) includes a printed circuit board body (21), a communication component (22) interconnected with the printed circuit board body (21), and a positioning pin mounting hole (23) provided on the printed circuit board body (21). The lower shell (3) includes a lower shell body (31) fixed on the microsystem packaging substrate (4), a connecting piece mounting hole (32) fixed in the lower shell body (31) and the connecting piece (5) and a positioning pin (33) located on the upper surface of the lower shell body (31) corresponding to the position of the positioning pin mounting hole (23). The upper part of the connecting piece (5) is provided with a first LGA array (51) and the lower part is provided with a BGA array. The optical module PCBA (2) also includes a second LGA array disposed at the bottom of the printed circuit board body (21). The first LGA array (51) and the second LGA array are arranged in the same way and form elastic contact points after assembly. The connecting piece (5) is interconnected with the microsystem packaging substrate (4) through the BGA array. The integration method for the microsystem of the optical module includes the following steps: S1. The connecting piece (5) is soldered to the microsystem packaging substrate (4) using reflow soldering; S2. The lower shell (3) is passed through the connecting piece (5) and fixed on the microsystem packaging substrate (4), and the mounting hole (32) of the connecting piece is tightly fitted with the connecting piece (5); S3. Insert the optical module PCBA (2) into the positioning pin (33) so that the positioning pin (33) enters the positioning pin mounting hole (23) and fixes the optical module PCBA (2) to the lower shell (3); S4. Fasten the top cover (1) and tighten it with screws to complete the integration of the microsystem for the optical module.

2. The microsystem integration method for optical modules according to claim 1, characterized in that: The optical module PCBA (2) also includes notches (24) at the four corners of the printed circuit board body (21), and the lower shell (3) also includes bosses (34) at the four corners of the lower shell body (31), with the notches (24) corresponding to the shapes of the bosses (34); In step S3, after the optical module PCBA (2) is inserted, the notch (24) is fixed to the boss (34).

3. The microsystem integration method for optical modules according to claim 2, characterized in that: The lower shell (3) also includes screw mounting holes (35) provided on the boss (34); The upper cover (1) includes an upper cover body (11) and upper cover screw mounting holes (12) provided at the four corners of the upper cover body (11). In step S4, the upper cover (1) is fastened, and the screws are passed through the upper cover screw mounting hole (12) and the screw mounting hole (35) in sequence to press the upper cover (1) against the optical module PCBA (2) and fix it on the lower shell (3).

4. A microsystem integration method for optical modules according to claim 2, characterized in that: The boss (34) is a fan-shaped protrusion with its arc surface facing the center of the lower shell body (31), and the notch (24) is a fan-shaped notch with its arc surface facing the outside of the printed circuit board body (21). The length and width of the upper cover (1), the printed circuit board body (21), and the lower shell body (31) are all the same.

5. A microsystem integration method for optical modules according to claim 2, characterized in that: The boss (34) and the notch (24) are tightly fitted with a positive tolerance of <0.01mm.

6. A microsystem integration method for optical modules according to claim 1, characterized in that: The mounting holes (32) and the connecting pieces (5) are both square and have corresponding dimensions, forming a tight fit after assembly. The positive tolerance of the mounting holes (32) and the connecting pieces (5) is <0.01mm. The upper cover (1) and the lower shell body (31) are made of copper plated with nickel; The lower shell body (31) is fixed to the microsystem packaging substrate (4) by adhesive.

7. A microsystem integration method for optical modules according to claim 1, characterized in that: The connecting piece (5) is made of plastic material prepared by injection molding; The first LGA array (51) meets the 30GHz signal transmission requirements.

8. A microsystem integration method for optical modules according to claim 1, characterized in that: The printed circuit board body (21) is made of high-frequency PCB board material.

9. A microsystem integration method for optical modules according to claim 1, characterized in that: The pin center distance of the optical module PCBA (2) is 0.8 mm, and the communication component (22) includes optical devices and optoelectronic devices.

10. A microsystem integration method for optical modules according to claim 3, characterized in that: The upper cover (1) also includes screw mounting clearance slots (13) at the four corners of the upper cover body (11) and printed circuit board clearance slots (14) on the back of the upper cover body (11), the printed circuit board clearance slots (14) being used to avoid the communication component (22).

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