Hermetic packaging method for microwave components based on printed circuit boards with embedded microchannels

Abstract

The present invention relates to the field of microelectronic packaging technology, and specifically discloses a hermetic packaging method for a microwave component based on a printed circuit board with embedded microchannels. Among them, the microwave component includes a metal packaging box body, a printed circuit board installed in the metal packaging box body and provided with microchannels, and a cantilever integrated with the printed circuit board and communicating with the microchannels; one end of the cantilever is integrally formed and connected to the printed circuit board, and the other end thereof passes through the metal packaging box body and is located outside the metal packaging box body; a liquid inlet and a liquid outlet communicating with the microchannels and located outside the metal packaging box body are arranged on the cantilever. And a hermetic packaging method for the microwave component is also disclosed. The present invention can effectively realize the integrated integration of the printed circuit board and the metal packaging structure to achieve hermetic packaging; has good heat dissipation ability, can realize the transmission of high-density electrical signals; and can realize uniform heat dissipation with low flow resistance.

Description

Technical Field

[0001] The present invention relates to the field of microelectronic packaging technology, and more specifically, to a hermetic packaging method for microwave components based on a printed circuit board with embedded microchannels. Background Art

[0002] With the wide application of the third-generation semiconductor technology represented by GaN and the further improvement of the integration density of electronic systems, the emission power of microwave components is increasing day by day, the self-heating effect of power devices is becoming more prominent, and the thermal management problem has gradually become a technical bottleneck restricting the development of electronic systems. The traditional passive heat dissipation technology based on heat sinks and heat diffusion of packaging boxes can no longer meet the heat dissipation requirements of high-power devices, and the thermal management technology using micro-cooling fluids to enhance heat dissipation has become an important solution.

[0003] Traditional high-power microwave components use a penetrative liquid cooling technology based on micro-cooling fluids to achieve efficient heat dissipation, that is, directly integrating liquid cooling microchannels in a metal packaging box, installing multiple circuit boards on both sides of the box, and using feed-through insulators to achieve the interconnection of electrical signals on both sides of the box. This integration method has the characteristics of simple integration structure and excellent heat dissipation performance; however, due to the feed-through insulators occupying a large area of the box, it restricts the improvement of the component integration density.

[0004] A printed circuit board is a general electronic system substrate, a provider of electrical connections for electronic components, and an important carrier for realizing high-density integration of electronic systems. Traditional printed circuit boards are mainly composed of organic dielectric layers and copper wiring layers. Due to the very low thermal conductivity of organic materials (usually <1 W / m·K), it is difficult to meet the needs of high-density integration of high-power devices.

[0005] Chinese Patent ZL202110118888.9 proposed a printed circuit board with embedded microchannels and its preparation method, which combines the microchannel heat dissipation technology with the high-density integration technology of printed circuit boards to achieve high heat flux density heat dissipation. However, this patent does not involve a metal packaging structure and does not constitute a microwave component.

[0006] Traditional printed circuit boards use the surface mount technology of packaging devices on the printed circuit board to achieve high-density integration. However, for high-power chips, in order to achieve their efficient heat dissipation, it is necessary to remove as much thermal resistance at the packaging interface as possible. Directly integrating bare chips on the surface of the microchannels in the printed circuit board has become one of the most effective methods for low-thermal-resistance integration. This poses higher requirements for the component packaging process based on printed circuit boards with embedded microchannels. Especially for high-reliability packaging application fields with airtightness requirements, there is an urgent need to develop a microwave component and a hermetic packaging method based on a printed circuit board with embedded microchannels.

[0007] Chinese Patent ZL202011304110.9 proposes a high heat dissipation digital - analog integrated packaging structure and its manufacturing method. It uses a high - low frequency digital - analog composite printed circuit board as an integrated carrier for components, chips, etc. Compared with ordinary hybrid integrated microwave components, the integration density is improved. However, this component still uses metal for passive heat conduction, and its heat dissipation ability is limited. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a hermetic packaging method for a microwave component based on a printed circuit board with embedded microchannels; it can effectively achieve the integrated integration of the printed circuit board and the metal packaging structure to realize hermetic packaging; it has good heat dissipation ability, can achieve the transmission of high - density electrical signals; and can achieve uniform heat dissipation with low flow resistance.

[0009] The solution adopted by the present invention to solve the technical problem is:

[0010] On the one hand:

[0011] The present invention discloses a microwave component based on a printed circuit board with embedded microchannels, including a metal packaging box body, a printed circuit board installed in the metal packaging box body and provided with microchannels, and a cantilever integrated with the printed circuit board and communicating with the microchannels;

[0012] One end of the cantilever is integrally formed and connected to the printed circuit board, and the other end passes through the metal packaging box body and is located outside the metal packaging box body;

[0013] The cantilever is provided with a liquid inlet and a liquid outlet that communicate with the microchannels and are located outside the metal packaging box body.

[0014] In the present invention, the liquid inlet and the liquid outlet are placed on the outside of the hermetic packaging component, avoiding the contamination of vulnerable components by cooling liquid or cooling liquid vapor, and improving the reliability of the component; using a printed circuit board with embedded microchannels as the substrate for electrical signal interconnection, and at the same time integrating the printed circuit board with embedded microchannels and the metal packaging structure integrally, realizing the integration of the structural functions of the component; having good heat dissipation effect.

[0015] In some possible implementation manners, the printed circuit board includes an upper wiring layer, a metal core board provided with microchannels, a lower wiring layer, and a vertical transmission structure provided on the metal core board and connected to the upper wiring layer and the lower wiring layer at both ends, which are stacked in sequence; the outside of the metal core board is connected to the end of the cantilever and integrally formed.

[0016] The metal packaging box body is provided with a through - hole for the cantilever to pass through, and a sealing connector is provided on the through - hole, and the airtight welding of the cantilever and the metal packaging box body is effectively realized through the sealing connector.

[0017] In some possible embodiments, a radio frequency module and a power supply module are integrated on the printed circuit board; a heat dissipation unit is disposed in the microchannel, and the heat dissipation unit is located directly below the radio frequency module.

[0018] Preferably, the heat flux density of the radio frequency module ≥ 300W / cm 2 , including a high-power radio frequency chip and a heat sink;

[0019] In some possible embodiments, in order to effectively solve the problem of the heat dissipation network layout caused by the layout of the radio frequency module, realize multi-channel, low-flow resistance uniform shunt and efficient uniform heat dissipation; at the same time, avoid phenomena such as leakage of the cooling fluid caused by improper layout of the vertical transmission structure;

[0020] The microchannel includes a plurality of parallel shunt inlet channels communicating with the inlet port, a microchannel connected to the outlet end of the shunt inlet channel, and an outlet channel connected in series with the outlet end of the microchannel; the outlet end of the outlet channel communicates with the outlet port; the vertical transmission structure is located between adjacent shunt inlet channels.

[0021] In some possible embodiments, the cross-sectional area of the outlet channel is larger than that of the shunt inlet channel.

[0022] In some possible embodiments, in order to effectively achieve the airtight welding of the sealed connector with the metal package box body and the cantilever respectively;

[0023] Overflow grooves are respectively arranged on the inner and outer sides of the sealed connector.

[0024] On the other hand:

[0025] The present invention also discloses an airtight packaging method for a microwave component based on a printed circuit board with an embedded microchannel, specifically including the following steps:

[0026] Step S1: Prepare a printed circuit board with an embedded microchannel, and ensure that there is no wiring layer on the cantilever;

[0027] Step S2: Integrate the radio frequency module and the power supply module on the printed circuit board through a low thermal resistance integration process, and integrate other components;

[0028] Step S3: Assemble the printed circuit board in step S2 with the metal package box body;

[0029] Step S4: Install the sealed connector and the welding ring, and weld the outer side of the sealed connector to the inner wall of the through hole, and the inner side of the sealed connector to the outer side of the cantilever;

[0030] Step S5: Perform capping by laser sealing or parallel sealing.

[0031] In some possible embodiments, to effectively integrate the radio frequency module and the power supply template;

[0032] The step S2 specifically refers to:

[0033] Pass the radio frequency module through the upper wiring layer and integrate it on the upper surface of the metal core board by a low thermal resistance integration process, and make it located directly above the heat dissipation unit;

[0034] Integrate the power supply template on the lower surface of the lower wiring layer by a low thermal resistance integration process.

[0035] In some possible embodiments, to effectively achieve the airtight welding of the sealed connector and the through hole;

[0036] The step S4 specifically refers to:

[0037] Insert the sealed connector and the solder ring on the through hole, so that the sealed connector is located between the through hole and the cantilever;

[0038] Perform welding to achieve the airtight welding of the cantilever and the through hole.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] The present invention uses a printed circuit board with an embedded microchannel as a substrate for electrical signal interconnection, and at the same time integrates it with the metal packaging box structure in an integrated manner, realizing the integration of the structural functions of the components; compared with the traditional through-type liquid-cooled metal packaging, the integration density can be increased by more than one time.

[0041] The present invention uses a printed circuit board with an embedded microchannel as a substrate for electrical signal interconnection. The cooling fluid enters the inner flow channel of the microchannel through the liquid inlet and is discharged through the liquid outlet, and a high heat flux density heat dissipation of more than 300 W / cm 2 above can be realized; compared with ordinary non-liquid-cooled packaging, its high-efficiency heat dissipation ability is increased by more than 3 times.

[0042] The present invention optimizes the welding structure and welding method to achieve the airtight welding of the liquid inlet and outlet cantilevers of the printed circuit board with the embedded microchannel and the metal packaging box body; compared with the traditional welding method of the printed circuit board and the metal box body, due to the removal of the organic material layer on the welding surface of the cantilever, the airtightness is higher; at the same time, the present invention places the liquid inlet and outlet on the outside of the airtight packaging component, avoiding the pollution of the cooling liquid or the cooling liquid vapor to the vulnerable components such as the chips in the component, and improving the reliability of the component.

[0043] The present invention adopts the mutual cooperation of multiple groups of shunt inlet flow channels in parallel and outlet flow channels in series, solves the problem of the heat dissipation network layout caused by the arrangement of high-power radio frequency modules, realizes multi-channel, low-flow resistance uniform shunt and efficient uniform heat dissipation within the component; at the same time, avoids phenomena such as leakage of cooling fluid caused by improper layout of the vertical transmission structure. Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of the present invention;

[0045] Figure 2 It is a schematic diagram of the connection relationship among the radio frequency module, power supply module and printed circuit board in the present invention;

[0046] Figure 3 It is a schematic diagram of the connection relationship among the micro-channel, inlet and outlet in the present invention;

[0047] Figure 4 It is a schematic structural diagram of the metal packaging box body in the present invention;

[0048] Figure 5 It is a schematic diagram after the printed circuit board and the metal packaging box body are assembled in the present invention;

[0049] Figure 6 It is a working flow chart of the preparation method in the present invention;

[0050] Wherein: 1. Microwave component; 2. Printed circuit board; 3. Inlet; 4. Outlet; 5. Radio frequency module; 6. Metal packaging box body; 7. Shunt inlet flow channel; 8. Outlet flow channel; 9. Through hole; 10. Cantilever; 11. Sealed connector; 12. Power supply module; 13. Lead wire; 14. Vertical transmission structure; 15. Metal circuit layer; 16. Semi-cured sheet and insulating layer; 17. Metal core board; 18. Micro-channel; 19. Heat dissipation unit. Detailed Embodiments

[0051] In the present invention, unless otherwise clearly specified and defined, terms such as "installation", "connection", "linkage", "fixation" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated as a whole; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two components or the interaction relationship between two components. The "first", "second" and similar terms mentioned in this application do not indicate any sequence, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "one" do not indicate a quantity limitation, but indicate that there is at least one. In the implementation of this application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In the description of the embodiments of this application, unless otherwise stated, the meaning of "a plurality of" refers to two or more. For example, a plurality of positioning posts refer to two or more positioning posts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] The present invention will be described in detail below.

[0053] Embodiment 1:

[0054] As Figures 1 - 6 shown:

[0055] This embodiment discloses a microwave component 1 based on a printed circuit board with an embedded microchannel, including a metal packaging box body 6, a printed circuit board 2 installed in the metal packaging box body 6 and provided with a microchannel 18, and a cantilever 10 integrated with the printed circuit board 2 and communicating with the microchannel 18;

[0056] One end of the cantilever 10 is integrally formed and connected with the printed circuit board 2, and the other end passes through the metal packaging box body 6 and is located outside the metal packaging box body 6;

[0057] The cantilever 10 is provided with a liquid inlet 3 and a liquid outlet 4 that communicate with the microchannel 18 and are located outside the metal packaging box body 6.

[0058] In the present invention, the liquid inlet 3 and the liquid outlet 4 are placed outside the hermetic packaging component, avoiding the contamination of vulnerable components by the cooling liquid or the cooling liquid vapor, and improving the reliability of the component; the printed circuit board 2 with the embedded microchannel 18 is used as the substrate for electrical signal interconnection, and at the same time, the printed circuit board 2 with the embedded microchannel 18 is integrated with the metal packaging structure, realizing the integration of the structural function of the component; it has a good heat dissipation effect.

[0059] In some possible embodiments, the printed circuit board 2 includes an upper wiring layer, a metal core board 17 provided with a microchannel 18, a lower wiring layer, and a vertical transmission structure 14 disposed on the metal core board 17 and connected to the upper wiring layer and the lower wiring layer at both ends, which are sequentially stacked; the outer side of the metal core board 17 is connected to the end of the cantilever 10 and integrally formed.

[0060] Preferably, the metal core board 17 includes a first core board provided with a microchannel 18 and integrally formed with the cantilever 10, and a second core board cooperatively installed with the first core board. The first core board and the second core board are connected by welding; the liquid inlet 3 and the liquid outlet 4 are communicated with the microchannel 18, and heat dissipation is achieved by the flow of the cooling fluid in the microchannel 18.

[0061] Preferably, the vertical transmission structure 14 is not communicated with the microchannel 18.

[0062] The metal core board 17 and the cantilever 10 are integrally formed and both are made of copper; the upper and lower sides of the cantilever 10 are not provided with an upper wiring layer and a lower wiring layer, and the cantilever 10 is hermetically connected to the metal packaging box 6.

[0063] Preferably, the upper wiring layer, the metal core board 17, and the lower wiring layer are connected by a lamination process.

[0064] The metal packaging box 6 is provided with a through hole 9 for the cantilever 10 to pass through, and a sealing connector 11 is provided on the through hole 9, and the hermetic welding of the cantilever 10 and the metal packaging box 6 is effectively realized through the sealing connector 11.

[0065] Preferably, the cantilever 10 can be one group or multiple groups; when it is one group, the liquid inlet 3 and the liquid outlet 4 are provided on the cantilever 10.

[0066] When the cantilever 10 is two groups, one group of cantilevers 10 is provided with the liquid inlet 3, and the other group is provided with the liquid outlet 4.

[0067] The present invention uses the printed circuit board 2 as a substrate for electrical signal interconnection, and by adopting the flow of the cooling fluid in the microchannel 18, heat dissipation with a high heat flux density of more than 300 W / cm 2 above can be achieved. Compared with ordinary non-liquid-cooled packages, its high-efficiency heat dissipation ability is increased by more than 3 times.

[0068] The airtight welding between the cantilever 10 and the metal packaging box 6 is achieved through the sealed connector 11. Compared with the traditional welding method between the printed circuit board 2 and the metal box, since there is no wiring layer (lower wiring layer, upper wiring layer) on the welding surface of the cantilever 10, the airtightness is higher. At the same time, the liquid inlet 3 and the liquid outlet 4 are respectively connected to the microchannels 18 in the metal core board 17 and are arranged on the cantilever 10. After assembly, the liquid inlet 3 and the liquid outlet 4 will be located outside the metal packaging box 6, avoiding the contamination of vulnerable components by the cooling liquid or the vapor of the cooling liquid, improving the reliability of the component, and effectively achieving heat dissipation at the same time.

[0069] In some possible implementation manners, a radio frequency module 5 and a power module 12 are integrated on the printed circuit board 2. A heat dissipation unit 19 is arranged in the microchannel 18, and the heat dissipation unit 19 is located directly below the radio frequency module 5.

[0070] Preferably, as Figure 2 shown, the radio frequency module 5 passes through the upper wiring layer and is integrated on the metal core board 17, and is connected to the upper wiring layer through a lead 13. The power module 12 is integrated on the side of the lower wiring layer away from the metal core board 17 and is connected to the lower wiring layer, and in combination with the vertical transmission structure 14, the radio frequency module 5 is powered nearby. By integrating the radio frequency module 5 on the surface of the metal core board 17 close to the upper wiring layer and adopting the method of being close to the signal output end of the component, the transmission path length of the radio frequency signal is shortened and the power loss is reduced.

[0071] In some possible implementation manners, in order to effectively solve the problem of the heat dissipation network layout caused by the arrangement of the radio frequency module 5, achieve multi-channel, low flow resistance uniform shunt and efficient uniform heat dissipation; at the same time, avoid phenomena such as leakage of the cooling fluid caused by improper layout of the vertical transmission structure 14;

[0072] The microchannel 18 includes multiple shunt inlet channels 7 in parallel with the liquid inlet 3, microchannels connected to the outlet ends of the shunt inlet channels 7, and outlet channels 8 in series with the outlet ends of the microchannels. The outlet end of the outlet channel 8 is connected to the liquid outlet 4. The vertical transmission structure 14 is located between two adjacent shunt inlet channels 7, so that the vertical transmission structure 14 and the microchannel 18 will not be connected, avoiding the cooling fluid in the microchannel 18 from entering the vertical transmission structure 14.

[0073] Adopting the arrangement method of multiple shunt inlet channels 7 connected to the liquid inlet 3, microchannels arranged corresponding to the inlet channels one by one, and outlet channels 8 in series connected to the microchannels solves the problem as Figure 3The heat dissipation network layout problem caused by the "left edge" layout of the radio frequency module 5 shown realizes multi-channel, low-flow resistance uniform shunt and efficient uniform heat dissipation within the component; at the same time, it avoids phenomena such as leakage of the cooling fluid caused by improper layout of the vertical transmission structure 14.

[0074] In some possible embodiments, the cross-sectional area of the liquid outlet flow channel 8 is larger than the cross-sectional area of the shunt inlet flow channel 7.

[0075] In some possible embodiments, in order to effectively achieve the airtight welding of the sealed connector 11 to the metal packaging box body 6 and the cantilever 10 respectively;

[0076] Overflow grooves are respectively arranged on the inner and outer sides of the sealed connector 11.

[0077] The sealed connector 11 is sleeved in the through hole 9, the cantilever 10 is inserted into the sealed connector 11 and penetrates through the sealed connector 11, and the airtight welding of the sealed connector 11 to the metal packaging box body 6 and the cantilever 10 is achieved by arranging overflow grooves on the inner and outer sides of the sealed connector 11.

[0078] Preferably, a radio frequency connection and a low-frequency connector are also installed on the metal packaging box body 6.

[0079] Embodiment 2:

[0080] As Figure 6 shown:

[0081] This embodiment also discloses the airtight packaging method of Embodiment 1, which specifically includes the following steps:

[0082] Step S1: Prepare the printed circuit board 2 with the embedded micro-channel 18, and make there be no wiring layer on the cantilever 10;

[0083] Step S2: Integrate the radio frequency module 5 and the power module 12 on the printed circuit board 2 through a low thermal resistance integration process, and integrate other components; specifically:

[0084] Pass the radio frequency module 5 through the upper wiring layer and integrate it on the surface of the metal core board 17 through a low thermal resistance integration process, and make it located directly above the heat dissipation unit 19;

[0085] Integrate the power supply template on the surface of the lower wiring layer through a low thermal resistance integration process;

[0086] Step S3: Assemble the printed circuit board 2 in Step S2 with the metal packaging box body 6;

[0087] Step S4: Install the sealed connector 22 and the welding ring, and weld the outer side of the sealed connector 11 to the inner wall of the through hole 9, and the inner side of the sealed connector 11 to the outer side of the cantilever 10; specifically:

[0088] Insert the sealed connector 11 and the solder ring into the through hole 9 such that the sealed connector 11 is located between the through hole 9 and the cantilever 10;

[0089] Perform soldering to achieve airtight soldering between the cantilever 10 and the through hole 9;

[0090] Step S5: Perform capping by laser sealing or parallel sealing.

[0091] The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, as well as any new combination of steps of any new method or process disclosed.

Claims

1. A hermetic packaging method for a microwave component based on a printed circuit board with embedded microchannels, characterized in that, The microwave component includes a metal packaging box body, a printed circuit board installed in the metal packaging box body and provided with a microchannel, and a cantilever integrated with the printed circuit board and communicating with the microchannel; one end of the cantilever is integrally formed and connected to the printed circuit board, and the other end thereof passes through the metal packaging box body and is located outside the metal packaging box body; the cantilever is provided with a liquid inlet and a liquid outlet that communicate with the microchannel and are located outside the metal packaging box body; the metal packaging box body is provided with a through hole for the cantilever to pass through, and a sealed connector is provided on the through hole. Specifically, it includes the following steps: Step S1: Prepare a printed circuit board with an embedded microchannel, and ensure that there is no wiring layer on the cantilever. Step S2: Integrate the radio frequency module and the power supply module on the printed circuit board through a low thermal resistance integration process, and integrate other components. Step S3: Assemble the printed circuit board in Step S2 with the metal packaging box body. Step S4: Install the sealed connector and the welding ring, and weld the outer side of the sealed connector to the inner wall of the through hole, and the inner side of the sealed connector to the outer side of the cantilever. Step S5: Use laser sealing or parallel sealing for capping.

2. The hermetic packaging method of a microwave component based on a printed circuit board with embedded microchannels according to claim 1, characterized in that Specifically, Step S2 means: Pass the radio frequency module through the upper wiring layer and integrate it on the upper surface of the metal core board through a low thermal resistance integration process. Integrate the power supply template on the lower surface of the lower wiring layer through a low thermal resistance integration process.

3. The hermetic packaging method of a microwave component based on a printed circuit board with embedded microchannels according to claim 1, characterized in that, Specifically, Step S4 means: Insert the sealed connector and the solder ring on the through hole, so that the sealed connector is located between the through hole and the cantilever. Perform welding to achieve airtight welding of the cantilever and the through hole.

4. The hermetic packaging method of a microwave component based on a printed circuit board with embedded microchannels according to claim 1, characterized in that The printed circuit board includes an upper wiring layer, a metal core board provided with a microchannel, a lower wiring layer, and a vertical transmission structure provided on the metal core board and connected to the upper wiring layer and the lower wiring layer at both ends, which are sequentially stacked; the outer side of the metal core board is connected and integrally formed with the end of the cantilever.

5. The hermetic packaging method of a microwave component based on a printed circuit board with embedded microchannels according to claim 4, characterized in that, A radio frequency module and a power supply module are integrated on the printed circuit board; a heat dissipation unit is arranged in the microchannel, and the heat dissipation unit is located directly below the radio frequency module.

6. A hermetic packaging method for a microwave component based on a printed circuit board with embedded microchannels according to claim 4, characterized in that, The microchannel includes a plurality of shunt inlet channels communicating with the liquid inlet, a microchannel connected to the outlet end of the shunt inlet channel, and an outlet channel connected in series with the outlet end of the microchannel; the outlet end of the outlet channel communicates with the liquid outlet.

7. A hermetic packaging method for a microwave component based on a printed circuit board with embedded microchannels according to claim 6, characterized in that, The cross-sectional area of the outlet channel is larger than that of the shunt inlet channel.

8. A hermetic packaging method for a microwave component based on an embedded microchannel printed circuit board according to claim 1, characterized in that, Overflow grooves are respectively arranged on the inner and outer sides of the sealed connector.

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