Microwave assembly high-frequency signal transmission structure and method

Abstract

The invention discloses a microwave component high-frequency signal transmission structure and method.The transmission structure comprises a first substrate and a second substrate which are assembled together, an assembling gap exists between the first substrate and the second substrate, the transmission structure further comprises a gold net connected to the assembling gap in a bridging mode, and the gold net is provided with a plurality of through holes; the gold net is bonded with the upper surface of the first substrate and the upper surface of the second substrate, microwave elements bonded with the gold net are assembled on the upper surface of the first substrate and the upper surface of the second substrate, and the microwave elements are in radio frequency cascade connection. According to the transmission structure, the problem of high-frequency signal resonance caused by assembly gaps is solved, meanwhile, the porous structure on the gold net is utilized, thermal stress generated by thermal mismatch between the first substrate and the second substrate is relieved, and the assembly stability and reliability of the transmission structure are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of microelectronic packaging, and in particular relates to a microwave component high-frequency signal transmission structure and method. Background Art

[0002] During the assembly process of microwave components, due to the influence of machined parts accuracy, circuit substrate size deviation and assembly deviation, there will be assembly gaps between the box body and the circuit substrate, between the circuit substrates, and between the circuit substrate and the chip. The assembly gap will deteriorate the common ground of high-frequency signal transmission, and resonance will occur at the assembly gap, affecting the performance of microwave components.

[0003] At present, in the prior art, for example, Chinese invention patent CN113161312B discloses a gradient gold ribbon interconnection structure between a chip and a transmission line and an assembly method thereof, which effectively reduces insertion loss by matching the width of the pad on the transmission line and the chip side with the gradient gold ribbon structure. However, for its structure, a large amount of electromagnetic leakage will be generated at the ground discontinuity during transmission of high-frequency signals, thereby causing performance degradation;

[0004] For example, Chinese invention patent CN110137789B discloses a thermally isolated high-frequency signal transmission structure in a directly modulated laser, which uses capacitors to overlap the transmission line to achieve the transmission of high-frequency signals above the assembly gap and avoid the thermal influence between the two assemblies. When this structure is used in a microwave assembly, there may be a risk of the overlapping capacitor falling off due to thermal stress. It discloses a typical gold wire cascade transmission structure and a circuit chip overlap transmission structure, wherein the gold wire cascade structure cannot solve the performance deterioration caused by the assembly gap, and the circuit chip overlap transmission structure cannot alleviate the stress caused by the thermal mismatch between the two assemblies;

[0005] That is, in the prior art, for the assembly of microwave components, it is impossible to simultaneously solve the limitations of the assembly gap and the influence of thermal stress during high-frequency signal transmission. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a high-frequency signal transmission structure and method for a microwave component. A gold mesh is connected across the assembly gap between a first substrate and a second substrate to achieve continuity of the microwave ground between the substrates, thereby solving the problem of high-frequency signal resonance caused by the assembly gap. At the same time, the porous structure of the gold mesh is utilized to alleviate the thermal stress caused by thermal mismatch between the first substrate and the second substrate, thereby improving the assembly stability and reliability of the transmission structure.

[0007] The object of the present invention is achieved through the following technical solutions:

[0008] A microwave component high-frequency signal transmission structure includes a first substrate and a second substrate assembled together, an assembly gap exists between the first substrate and the second substrate, and a gold mesh bridged across the assembly gap, the gold mesh having a plurality of through holes, the gold mesh being bonded to the upper surfaces of the first substrate and the second substrate respectively, the upper surfaces of the first substrate and the second substrate being both equipped with microwave elements bonded to the gold mesh, and the microwave elements being cascaded together in radio frequency connection.

[0009] In one embodiment, the microwave element is bonded to the gold mesh via conductive adhesive.

[0010] In one embodiment, the microwave elements are cascaded together via gold wires or gold ribbons.

[0011] In one embodiment, the through hole is a rectangular structure, and a plurality of through holes are distributed in an array on the gold mesh.

[0012] In one embodiment, the first substrate is a microwave component housing, the second substrate is a circuit substrate, and the second substrate is bonded to the first substrate by conductive adhesive.

[0013] The present invention also provides a microwave component high-frequency signal transmission method, comprising the following steps:

[0014] Step S1, determining the size of the gold mesh;

[0015] Step S2, bonding the gold mesh to the upper surfaces of the first substrate and the second substrate by electronic welding or ultrasonic hot pressing, and making the gold mesh bridge the assembly gap between the first substrate and the second substrate;

[0016] Step S3, applying conductive glue on the upper surfaces of the first substrate and the second substrate, wherein the conductive glue covers the bonding area corresponding to the microwave element;

[0017] Step S4, placing the microwave component on the bonding area and completing the curing of the conductive adhesive;

[0018] Step S5: realizing radio frequency interconnection between microwave components.

[0019] In one embodiment, in step S1, determining the size of the gold mesh includes:

[0020] The microwave transmission requirements, the material properties of the first substrate, the material properties of the second substrate, and the size of the assembly gap are obtained, and electromagnetic and thermal field simulations are performed to determine the thickness of the gold mesh, the size of the through holes thereon, and the spacing between the through holes.

[0021] In one embodiment, in step S5, cascading microwave components together comprises:

[0022] The cascade gold wire or cascade gold ribbon is bonded to the pad of the microwave component by ultrasonic hot pressing.

[0023] The beneficial effects of the present invention are:

[0024] By connecting the gold mesh across the assembly gap between the first substrate and the second substrate, the continuity of the microwave ground between the substrates is achieved, and the problem of high-frequency signal resonance caused by the assembly gap is solved. At the same time, the porous structure on the gold mesh is used to alleviate the thermal stress caused by thermal mismatch between the first substrate and the second substrate, thereby improving the assembly stability and reliability of the transmission structure and solving the problem of microwave component performance affected by the assembly gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0026] Figure 1 A schematic structural diagram of an embodiment of the present invention is shown;

[0027] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0028] Reference numerals:

[0029] 1-first substrate, 2-second substrate, 3-gold mesh, 4-conductive glue, 5-first microwave element, 6-second microwave element, 7-cascade gold wire. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] The present invention provides a microwave component high frequency signal transmission structure, such as Figure 1 As shown, it includes a first substrate 1 and a second substrate 2 assembled together, an assembly gap exists between the first substrate 1 and the second substrate 2, and also includes a gold mesh 3 straddling the assembly gap, the gold mesh 3 has a plurality of through holes, the gold mesh 3 is bonded to the upper surfaces of the first substrate 1 and the second substrate 2 respectively, the upper surfaces of the first substrate 1 and the second substrate 2 are both equipped with microwave components bonded to the gold mesh 3, and the microwave components are cascaded together by radio frequency;

[0032] It should be noted that, in the present embodiment, the first substrate 1 is a shell of a microwave component, the second substrate 2 is a circuit substrate, the second substrate 2 is bonded to the first substrate 1 with a conductive adhesive 4, the first substrate 1 and the second substrate 2 can both be circuit substrates, or the first substrate 1 can be a circuit substrate and the second substrate 2 can be a shell of a microwave component. Due to the influence of the precision of machined parts, the size deviation of the circuit substrate, the assembly deviation, etc., in the actual assembly process, there is an assembly gap between the first substrate 1 and the second substrate, and the assembly gap affects the performance of the microwave component. In the present embodiment, the continuity of the microwave ground between the first substrate 1 and the second substrate 2 is achieved through the gold mesh 3, and at the same time, the multiple through holes on the gold mesh 3 can alleviate the influence of the thermal stress between the first substrate 1 and the second substrate 2 on the assembly reliability of the transmission structure. Through a simple structure, the problem of high-frequency signal resonance caused by the assembly gap is solved, and the thermal stress caused by thermal mismatch between the first substrate 1 and the second substrate 2 is alleviated.

[0033] Specifically, the microwave element is bonded to the gold mesh 3 by means of a conductive adhesive 4, and the microwave elements are cascaded together by means of gold wires or gold ribbons;

[0034] In one embodiment, Figure 1 As shown, the through hole is a rectangular structure, and a plurality of through holes are distributed in an array on the gold mesh 3, which further improves its ability to relieve thermal stress and also facilitates the design of the through hole size and hole spacing of the gold mesh 3;

[0035] In one embodiment, the first substrate 1 is a microwave component shell, the material is aluminum alloy, and the surface is partially gold-plated. The second substrate 2 is an LTCC (low temperature co-fired ceramic) circuit substrate, and the surface conductor is sintered by gold paste. The second substrate 2 is bonded to the first substrate 1 with a conductive adhesive 4, and the conductive adhesive 4 is the mainstream conductive adhesive 4 adhesive H20E in the industry. The first microwave element 5 is a microstrip transmission line prepared using a soft substrate microwave printed circuit board, the surface is copper-based gold-plated, the back is copper-based gold-plated, and the conductive strip width meets the 50Ω matching of radio frequency transmission. The second microwave element 6 is a microwave bare chip for matching signal transmission, and the cascade gold wire 7 is two 25um diameter gold wires. The gold mesh 3 can be based on the 6-18GHz broadband radio frequency signal transmission characteristics, combined with the material properties of the first substrate 1 and the second substrate 2 and the size of the assembly gap to perform electromagnetic field and thermal field simulation to obtain the optimal through-hole size and the optimal hole spacing of the gold mesh 3, such as Figure 1As shown, the second substrate 2 is bonded to the first substrate 1 by using a conductive adhesive 4, and the gold mesh 3 is pressed and welded on the surfaces of the first substrate 1 and the second substrate 2 by electronic spot welding, so that the gold mesh 3 is connected across the assembly gap between the first substrate 1 and the second substrate 2, and the conductive adhesive 4 is spot-coated on the bonding area on the upper surface of the first substrate 1 and the second substrate 2, and the conductive adhesive 4 covers the corresponding area of ​​the gold mesh 3, and the first microwave element 5 and the second microwave element 6 are bonded to the gold mesh 3. Through the fluidity of the conductive adhesive 4, the first microwave element 5 is bonded to the first substrate 1, and the second microwave element 6 is bonded to the second substrate 2, and the cascade gold wire 7 is bonded to the pads of the first microwave element 5 and the second microwave element 6;

[0036] In one embodiment, the present invention further provides a microwave component high frequency signal transmission method, comprising the following steps:

[0037] Step S1, determining the size of the gold mesh;

[0038] Step S2, bonding the gold mesh to the upper surfaces of the first substrate and the second substrate by electronic welding or ultrasonic hot pressing, and making the gold mesh bridge the assembly gap between the first substrate and the second substrate;

[0039] Step S3, applying conductive glue on the upper surfaces of the first substrate and the second substrate, wherein the conductive glue covers the bonding area corresponding to the microwave element;

[0040] Step S4, placing the microwave component on the bonding area and completing the curing of the conductive adhesive;

[0041] Step S5, cascading the microwave components together by radio frequency;

[0042] Specifically, in step S1, determining the size of the gold mesh includes:

[0043] Obtain microwave transmission requirements, material properties of the first substrate, material properties of the second substrate, and the size of the assembly gap, perform electromagnetic field and thermal field simulations, and determine the thickness of the gold mesh, the size of the through holes thereon, and the spacing between the through holes;

[0044] Further, in step S5, the microwave components are cascaded together, including:

[0045] The cascade gold wire or cascade gold ribbon is bonded to the pad of the microwave component by ultrasonic hot pressing;

[0046] In this embodiment, that is, for the microwave component transmission structure, gold wires that span the assembly gaps are bonded on two substrates with assembly gaps, and the continuity of the microwave ground between the substrates is achieved by using the gold wires, which solves the problem of high-frequency signal resonance caused by the assembly gaps. At the same time, the through holes on the gold wires are used to relieve the thermal stress caused by thermal mismatch between the first substrate and the second substrate, thereby improving the assembly stability and reliability of the transmission structure.

[0047] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0048] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A microwave component high-frequency signal transmission structure, comprising a first substrate and a second substrate assembled together, with an assembly gap between the first substrate and the second substrate, characterized in that: It also includes a gold mesh spanning the assembly gap, the gold mesh having a plurality of through holes, the gold mesh being bonded to the upper surfaces of the first substrate and the second substrate respectively, the upper surfaces of the first substrate and the second substrate being both equipped with microwave elements bonded to the gold mesh, and the microwave elements being cascaded together in radio frequency.

2. A microwave component high frequency signal transmission structure according to claim 1, characterized in that: The microwave element is bonded to the gold mesh via conductive adhesive.

3. The microwave component high frequency signal transmission structure according to claim 1, characterized in that: The microwave elements are cascaded together through gold wires or gold ribbons.

4. The microwave component high frequency signal transmission structure according to claim 1, characterized in that: The through hole is a rectangular structure, and a plurality of through holes are distributed in an array on the gold mesh.

5. The microwave component high frequency signal transmission structure according to claim 1, characterized in that: The first substrate is a microwave component housing, the second substrate is a circuit substrate, and the second substrate is bonded to the first substrate by conductive adhesive.

6. A microwave component high frequency signal transmission method, characterized in that: The steps include: Step S1, determining the size of the gold mesh; Step S2, bonding the gold mesh to the upper surfaces of the first substrate and the second substrate by electronic welding or ultrasonic hot pressing, and making the gold mesh bridge the assembly gap between the first substrate and the second substrate; Step S3, applying conductive glue on the upper surfaces of the first substrate and the second substrate, wherein the conductive glue covers the bonding area corresponding to the microwave element; Step S4, placing the microwave component on the bonding area and completing the curing of the conductive adhesive; Step S5: realizing radio frequency interconnection between microwave components.

7. A microwave component high frequency signal transmission method according to claim 6, characterized in that: In step S1, the size of the gold mesh is determined, including: According to the high-frequency signal transmission characteristics, the material and dielectric properties of the first substrate, the material and dielectric properties of the second substrate, and the size of the assembly gap, electromagnetic field and thermal field simulations are performed to determine the thickness of the gold mesh, the size of the through holes thereon, and the spacing between the through holes.

8. A microwave component high frequency signal transmission method according to claim 6, characterized in that: In step S5, radio frequency interconnection between microwave components is achieved, including: The cascade gold wire or cascade gold ribbon is bonded to the pad of the microwave component by ultrasonic hot pressing.

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