Three-dimensional radio frequency microsystem and method for manufacturing same

Abstract

The present application relates to a kind of three-dimensional radio frequency microsystem and preparation method thereof, belong to semiconductor technical field, solve the problem that the existing three-dimensional radio frequency microsystem cannot fully utilize interlayer space, heat dissipation path is long.The three-dimensional radio frequency microsystem includes multiple radio frequency function layers and interlayer heat dissipation microchannel, the interlayer heat dissipation microchannel includes 3D printing microchannel and micro heat sink arranged in 3D printing microchannel;The interlayer heat dissipation microchannel is arranged between adjacent two radio frequency function layers, and the radio frequency function layer to be cooled and the side of the interlayer heat dissipation microchannel provided with micro heat sink contact.The three-dimensional radio frequency microsystem of the present application is arranged between adjacent two radio frequency function layers independent interlayer heat dissipation microchannel, fully utilizes interlayer space, heat dissipation path is short, and heat dissipation capacity is stronger, and microchannel is 3D printing preparation, and preparation method is simple.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a three-dimensional radio frequency microsystem and its fabrication method. Background Technology

[0002] Radio frequency microsystems (RF microsystems) have been widely used in RF electronic applications such as radar, communication, navigation, and remote sensing due to their miniaturization, low cost, and high performance. They can realize phased array antennas with higher integration and lower profile, and have great application value.

[0003] Currently, RF microsystems are mainly in the System-on-Package (SiP) stage, which utilizes multi-chip system-level three-dimensional integration to realize RF microsystems. The chips are arranged in a three-dimensional layout, typically with high-power chips at the bottom and low-power chips at the top. This multi-layered heat source stacking leads to significant thermal coupling effects, while the reduction in package size increases the volume heat flux density. Furthermore, the gradual application of GaN third-generation semiconductor materials has led to a sharp increase in the surface heat flux density of power amplifier chips. In addition, when integrating antennas into RF microsystems, upward heat dissipation paths cannot be utilized, further increasing the difficulty of heat dissipation. Therefore, how to achieve efficient heat dissipation within limited space has become an urgent problem to be solved.

[0004] Current heat dissipation technologies for radio frequency microsystems are mainly divided into two categories: chip-level heat dissipation and package-level heat dissipation. Chip-level heat dissipation primarily includes two methods: on-chip etching to create microfluidic channels for heat dissipation and using highly thermally conductive diamond substrates to increase the heat dissipation area. Etching channels on the chip increases the cavity ratio, making it prone to breakage during manufacturing and resulting in poor process feasibility. On the other hand, using diamond substrates for heat homogenization also presents cost and process challenges. Furthermore, chip-level heat dissipation needs to be combined with package-level heat dissipation to achieve the final heat removal.

[0005] One existing solution for package-level heat dissipation is based on a chip-heat sink-package-cold plate heat dissipation path. This approach improves heat dissipation by applying high-efficiency thermal packaging / interface materials to enhance the heat exchange capacity of the cold plate, but the heat dissipation capacity is only around 200W / cm². 2 This approach cannot meet the heat dissipation requirements of high-power chips. Furthermore, for the three-dimensional stacked structure, the heat dissipation paths from the central chip to both sides are very long, hindering efficient heat dissipation. Another heat dissipation solution is single-layer internal heat dissipation, using microchannels fabricated on silicon or diamond for intra-layer heat dissipation. However, this approach cannot fully utilize the interlayer space. Additionally, fabricating microchannels on silicon adds a wafer-level process layer, and simultaneously meeting the requirements for high-frequency electrical signal interconnection and channel interconnection, making the process highly complex. Fabrication on diamond involves drilling processes, which are both costly and technically challenging. Summary of the Invention

[0006] In view of the above analysis, the present invention aims to provide a three-dimensional radio frequency microsystem and its fabrication method to solve at least one of the following problems existing in the three-dimensional radio frequency microsystem: (1) long heat dissipation path, which makes it impossible to achieve efficient heat dissipation; (2) inability to make full use of interlayer space; (3) high difficulty in fabricating ultra-thin heat dissipation microchannels.

[0007] On one hand, the present invention provides a three-dimensional radio frequency microsystem, which includes multiple radio frequency functional layers and interlayer heat dissipation microchannels, wherein the interlayer heat dissipation microchannels include 3D printed microchannels and micro heat sinks disposed in the 3D printed microchannels;

[0008] The interlayer heat dissipation microchannel is disposed between two adjacent radio frequency functional layers, and the radio frequency functional layer to be dissipated is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is disposed.

[0009] Preferably, the radio frequency functional layer includes a first radio frequency functional layer and a second radio frequency functional layer, wherein the first radio frequency functional layer is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is provided, and a chip is disposed in the first radio frequency functional layer.

[0010] Preferably, an antenna is disposed on the upper surface of the first radio frequency functional layer;

[0011] And / or, the chip is a PA or a multi-functional chip.

[0012] Preferably, the second radio frequency functional layer is one or more of a filter, duplexer, radio frequency switch, mixer, and digital-to-analog converter.

[0013] Preferably, the second radio frequency functional layer is provided with ports that are respectively connected to the inlet and outlet of the interlayer heat dissipation microchannel.

[0014] Preferably, adjacent radio frequency functional layers are interconnected via solder balls.

[0015] Preferably, the solder ball penetrates the interlayer heat dissipation microchannel between adjacent radio frequency functional layers.

[0016] Preferably, the interlayer heat dissipation microchannels are connected to the radio frequency functional layer by adhesive.

[0017] Preferably, the adhesive is TIM adhesive or conductive adhesive.

[0018] On the other hand, the present invention also provides a method for fabricating a three-dimensional radio frequency microsystem, for fabricating the above-mentioned three-dimensional radio frequency microsystem, the fabrication method comprising:

[0019] Step (1): Combine the micro heat sink with the 3D printing platform and 3D print microchannels around the micro heat sink to obtain interlayer heat dissipation microchannels;

[0020] Step (2): Combine the interlayer heat dissipation microchannel with the radio frequency functional layer, and make contact between the radio frequency functional layer to be dissipated and the side of the interlayer heat dissipation microchannel with micro heat sink.

[0021] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0022] 1. The three-dimensional radio frequency microsystem of the present invention sets an independent interlayer heat dissipation microchannel between two adjacent radio frequency functional layers. The radio frequency functional layer to be cooled is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is provided. The heat in the radio frequency functional layer to be cooled is transferred to the interlayer heat dissipation microchannel through the micro heat sink, thereby achieving heat dissipation. The present invention makes full use of the interlayer space, with a short heat dissipation path and strong heat dissipation capacity. Moreover, the microchannel is prepared by 3D printing, and the preparation method is simple.

[0023] 2. In the three-dimensional radio frequency microsystem of the present invention, the interlayer heat dissipation microchannel is an independent microchannel that can be flexibly arranged in the gaps between different structural layers in the package, making full use of the interlayer gaps. Moreover, the interlayer heat dissipation microchannel is small in size and can be tightly integrated with high-power chips, effectively shortening the heat dissipation path and improving the heat dissipation effect. The microchannel is made of resin material and can be prepared by 3D printing, which is a simple preparation method.

[0024] 3. This invention combines a micro heat sink structure with a 3D printed microchannel to better transfer heat from the chip to the cooling medium, thus solving the problem of poor heat dissipation in 3D printed microchannels.

[0025] 4. The connection surface between the microchannel layer and the microheat sink in this invention is a stepped connection, which improves the sealing between the microheat sink and the microchannel layer.

[0026] 5. This invention increases the heat dissipation area and improves the heat dissipation effect by setting fins on the micro heat sink structure.

[0027] 6. This invention uses 3D printing technology to prepare interlayer heat dissipation microchannels, which has low cost, simple process, high precision, and small microchannel size.

[0028] 7. The three-dimensional radio frequency microsystem of the present invention can also incorporate other existing heat dissipation technologies (such as surface heat dissipation). The interlayer heat dissipation microchannel of the present invention utilizes space differently from existing heat dissipation technologies (such as surface heat dissipation). Therefore, the interlayer heat dissipation microchannel does not conflict with existing heat dissipation technologies and can be combined with them to jointly improve the heat dissipation effect of the three-dimensional radio frequency microsystem.

[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0031] Figure 1 This is a schematic diagram of the three-dimensional radio frequency microsystem structure of the present invention;

[0032] Figure 2 This is a schematic diagram of the interlayer heat dissipation microchannel structure of the present invention;

[0033] Figure 3 This is a top perspective view of the interlayer heat dissipation microchannel of the present invention;

[0034] Figure 4 A bottom view of the micro-heat sink;

[0035] Figure 5 To form a metal sacrificial layer on one side of the glass substrate;

[0036] Figure 6 To combine the other side of the glass substrate with the 3D printing platform;

[0037] Figure 7 To combine the micro heat sink with the glass substrate;

[0038] Figure 8 For printing microchannel layers;

[0039] Figure 9 For printing the cover plate layer;

[0040] Figure 10 To separate the glass substrate from the 3D printing platform;

[0041] Figure 11 To obtain interlayer heat dissipation microchannels after removing the sacrificial layer;

[0042] Figure 12 To integrate the side with the micro heat sink in the interlayer heat dissipation microchannel with the first radio frequency functional layer;

[0043] Figure 13 To combine the side of the interlayer heat dissipation microchannel without micro heat sinks with the second RF functional layer to form a three-dimensional RF microsystem;

[0044] Figure 14This is a schematic diagram of the structure of a microchannel heat dissipation performance testing device for interlayer heat dissipation.

[0045] Figure label:

[0046] 01-First RF functional layer; 02-Second RF functional layer; 03-Chip; 04-Antenna; 05-Solder ball;

[0047] 1-Microchannel layer; 2-Cover plate layer; 3-Micro heat sink; 301-Fin; 4-Flow channel; 5-Cooling medium inlet; 6-Cooling medium outlet; 7-Solder ball placement area;

[0048] 8-Glass carrier; 9-Metal sacrificial layer; 10-3D printing platform; 11-Substrate; 12-Thermal test chip. Detailed Implementation

[0049] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0050] On the one hand, the present invention provides a three-dimensional radio frequency microsystem, such as Figure 1 As shown, the three-dimensional radio frequency microsystem includes multiple radio frequency functional layers and interlayer heat dissipation microchannels. The interlayer heat dissipation microchannels include 3D printed microchannels and micro heat sinks 3 disposed in the 3D printed microchannels; the 3D printed microchannels are made of resin.

[0051] The interlayer heat dissipation microchannel is disposed between two adjacent radio frequency functional layers, and the radio frequency functional layer to be dissipated is in contact with the side of the interlayer heat dissipation microchannel where the micro heat sink 3 is disposed.

[0052] During implementation, a cooling medium (e.g., water) is circulated into the interlayer heat dissipation microchannels. The radio frequency functional layer that needs heat dissipation transfers heat to the micro heat sink. The micro heat sink comes into contact with the cooling medium, which then carries away the heat from the micro heat sink, thereby achieving the function of heat dissipation.

[0053] Compared with the prior art, the three-dimensional radio frequency microsystem of the present invention sets up an interlayer heat dissipation microchannel between two adjacent radio frequency functional layers. The radio frequency functional layer to be cooled is in contact with the side of the interlayer heat dissipation microchannel with a micro heat sink. The heat in the radio frequency functional layer to be cooled is transferred to the interlayer heat dissipation microchannel through the micro heat sink, thereby achieving heat dissipation. The present invention makes full use of the interlayer space, with a short heat dissipation path and strong heat dissipation capacity. Moreover, the microchannel is prepared by 3D printing, and the preparation method is simple.

[0054] Specifically, such as Figures 2-4 As shown (only one micro heat sink is shown), the interlayer heat dissipation microchannel includes a microchannel layer 1, a cover plate layer 2, and a micro heat sink 3; the materials of the microchannel layer 1 and the cover plate layer 2 are both resin.

[0055] The micro heat sink 3 is disposed in the microchannel layer 1, and the microchannel layer 1, the micro heat sink 3 and the cover plate layer 2 form a flow channel 4 for the flow of cooling medium.

[0056] The interlayer heat dissipation microchannels of the present invention are independent microchannels that can be flexibly arranged in the gaps between different structural layers in the package, making full use of the interlayer gaps. Moreover, the interlayer heat dissipation microchannels are small in size (down to the micrometer level), which can be tightly integrated with high-power chips, effectively shortening the heat dissipation path and improving the heat dissipation effect. The microchannels are made of resin material and can be prepared by 3D printing, which is a simple preparation method.

[0057] In this invention, the microchannel layer 1 and the cover plate layer 2 are made by 3D printing. The 3D printed structure is combined with the micro heat sink structure to better transfer heat from the heat dissipation layer to the cooling medium, thus solving the problem of poor heat dissipation effect of 3D printed microchannels.

[0058] For example, the micro heat sink 3 is provided with a plurality of fins 301 on the side near the cover plate layer 2, and the plurality of fins 301 are located in the flow channel 4. The plurality of fins 301 can increase the contact area between the cooling medium and the micro heat sink, thereby improving the heat dissipation effect.

[0059] For example, such as Figure 4 As shown, the fins 301 are cubic blocks, and the cubic blocks of fins 301 are distributed in a matrix on the side of the micro heat sink 3 near the cover plate layer 2.

[0060] For example, the distance between adjacent fins 301 is 100-400 μm.

[0061] For example, the side length of the cross section of the fin 301 facing the cover plate layer 2 is equal to the distance between adjacent fins 301.

[0062] In this invention, if the thickness of the flow channel 4 is too thin or the fins 301 are too short, it will be detrimental to heat dissipation.

[0063] For example, the length of the fin 301 extending from away from the cover plate layer 2 toward closer to the cover plate layer 2 is 50-200 μm, more preferably 100-200 μm.

[0064] For example, the thickness of the flow channel 4 is 70-220 μm, more preferably 120-200 μm.

[0065] For example, the side of the micro heat sink 3 away from the cover layer 2 is flush with the side of the microchannel layer 1 away from the cover layer 2. This facilitates integration with the heat dissipation layer in a three-dimensional radio frequency microsystem.

[0066] For example, the connection surface between the micro heat sink 3 and the microchannel layer 1 is stepped. This can improve the sealing between the micro heat sink 3 and the microchannel layer 1.

[0067] For example, the connection surface of the microchannel layer 1 that contacts the micro heat sink 3 forms a stepped connection surface resembling a descending staircase, extending from the side of the microchannel layer 1 away from the cover plate layer 2 towards the side of the microchannel layer 1 closer to the cover plate layer 2. In this embodiment, the large contact area between the micro heat sink 3 and the heat dissipation layer facilitates the transfer of heat from the heat dissipation layer to the micro heat sink 3.

[0068] For example, the material of the micro heat sink 3 is a copper-based material and / or a silicon-based material.

[0069] To improve heat dissipation performance, the material of the micro heat sink 3 is preferably a copper-based material, such as copper, which has high thermal conductivity and good machinability.

[0070] In this invention, the interlayer heat dissipation microchannels can be fabricated by 3D printing, and the overall thickness of the interlayer heat dissipation microchannels is 300-500 μm. Specifically, the cover layer 2 has a thickness of 100-150 μm, and the overall thickness of the microchannel layer 1 and the channel 4 is 150-400 μm.

[0071] For example, at least one cooling medium inlet 5 and at least one cooling medium outlet 6 are provided on the cover plate layer 2. Since the overall thickness of the interlayer heat dissipation microchannel is relatively thin, it is not suitable to set the cooling medium inlet and outlet on both sides of the microchannel. Therefore, the inlet and outlet are set on the cover plate layer 2.

[0072] For example, the flow channel 4 includes a plurality of sub-flow channels extending from the cooling medium inlet 5 to the cooling medium outlet 6, with each sub-flow channel having its two ends connected to the cooling medium inlet 5 and the cooling medium outlet 6, respectively.

[0073] For example, a solder ball placement area 7 is provided in the non-channel region of the interlayer heat dissipation microchannel. The solder ball placement area 7 extends through both the upper and lower surfaces of the interlayer heat dissipation microchannel. Simultaneously, the solder ball placement area 7 must avoid the cooling medium inlet 5 and the cooling medium outlet 6, such as... Figure 3 As shown.

[0074] It should be noted that the number of radio frequency functional layers in the three-dimensional radio frequency microsystem of the present invention is not limited, and can be two or more. Regardless of the number of radio frequency functional layers, interlayer heat dissipation microchannels can be set between adjacent radio frequency functional layers.

[0075] For example, such as Figure 1 As shown ( Figure 1(Taking two radio frequency functional layers as an example), the radio frequency functional layer includes a first radio frequency functional layer 01 and a second radio frequency functional layer 02. The first radio frequency functional layer 01 is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink 3 is provided. A chip 03 is provided in the first radio frequency functional layer 01.

[0076] To achieve high-frequency, low-loss transmission, antennas and chips are typically integrated into a radio frequency (RF) microsystem. Specifically, chip 03 is housed in the first RF functional layer 01, and antenna 04 is mounted on the upper surface of the first RF functional layer 01. Thus, the first RF functional layer 01 is an integrated RF microsystem with an antenna. In this integrated RF microsystem, antenna 04 blocks the upward heat dissipation path, preventing upward heat dissipation. Therefore, a downward heat dissipation path is provided through interlayer heat dissipation microchannels.

[0077] For example, the chip is a PA or a multi-functional chip.

[0078] For example, the interlayer heat dissipation microchannel includes multiple micro heat sinks 3, each micro heat sink 3 corresponding to a chip 03, such as... Figure 12 and Figure 13 As shown, this helps to shorten the heat dissipation path and efficiently dissipate the heat generated by chip 03.

[0079] For example, the second RF functional layer 02 can be one or more of a filter, duplexer and RF switch, mixer, and digital-to-analog converter.

[0080] In order to cooperate with the cooling medium inlet 5 and cooling medium outlet 6 of the interlayer microchannel, the second radio frequency functional layer 02 is provided with ports that are respectively connected to the cooling medium inlet 5 and cooling medium outlet 6 in the interlayer heat dissipation microchannel.

[0081] For example, adjacent radio frequency functional layers are interconnected via solder balls 05.

[0082] Specifically, the solder ball 05 penetrates the interlayer heat dissipation microchannel between adjacent radio frequency functional layers.

[0083] It is understood that the solder balls 05 interconnect adjacent radio frequency functional layers through the solder ball placement area of ​​the interlayer heat dissipation microchannel.

[0084] It is understandable that chip 03, antenna 04, and solder ball 05 are interconnected by metal wires.

[0085] For example, the interlayer heat dissipation microchannels are connected to the radio frequency functional layer by adhesive.

[0086] For example, the adhesive is TIM adhesive or conductive adhesive.

[0087] On the other hand, the present invention also provides a method for fabricating a three-dimensional radio frequency microsystem, used to fabricate the aforementioned three-dimensional radio frequency microsystem, such as... Figures 5-13 As shown, the preparation method includes:

[0088] Step (1): Combine the micro heat sink with the 3D printing platform and 3D print microchannels around the micro heat sink to obtain interlayer heat dissipation microchannels;

[0089] Step (2): Combine the interlayer heat dissipation microchannel with the radio frequency functional layer, and make contact with the side of the interlayer heat dissipation microchannel where the micro heat sink is located.

[0090] Specifically, step (1) includes:

[0091] Step (a): Form a metal sacrificial layer 9 on one side of the glass substrate 8;

[0092] Step (b): Combine the other side of the glass substrate 8 with the 3D printing platform 10;

[0093] Step (c): Combine the micro heat sink 3 with the glass substrate 8;

[0094] Step (d): Print microchannel layer 1 and cover plate layer 2 sequentially;

[0095] Step (e): Separate the glass substrate 8 from the 3D printing platform 10 by prying it open;

[0096] Step (f): Remove the sacrificial layer 9 to separate the microchannel from the glass substrate 8 and obtain the interlayer heat dissipation microchannel.

[0097] For example, in step (a), a metal sacrificial layer 9 is formed on one side of the glass substrate 8 by FHR magnetron sputtering.

[0098] For example, the metal sacrificial layer 9 is made of Cu and / or Au.

[0099] For example, in step (b), the glass substrate 8 is bonded to the 3D printing platform 10 by adhesive.

[0100] For example, the micro heat sink 3 can be fabricated on a copper-based material by processes such as photolithography, etching, and surface treatment. The specific operation steps are conventional in the field and will not be described in detail here.

[0101] For example, in step (c), the micro heat sink 3 is bonded to the glass substrate 8 by adhesive.

[0102] For example, in step (d), when printing the cover plate layer 2, a cooling medium inlet 5 and a cooling medium outlet 6 are reserved.

[0103] When interlayer heat dissipation microchannels are applied to three-dimensional radio frequency systems, electrical connections, such as solder balls, are required between different structural layers in the package. Therefore, during 3D printing, a solder ball placement area 7 is reserved in the non-channel region of the interlayer heat dissipation microchannels.

[0104] For example, in step (d), the 3D printing includes: using 3D printing based on projection micro stereolithography (PμSL). First, a three-dimensional structural model is constructed using modeling software; then, slicing software is used to slice the three-dimensional model with a certain layer thickness to obtain a series of two-dimensional images with specific patterns; then, the PμSL 3D printing system is used to project and expose each layer of the sliced ​​pattern onto the entire surface; the previous step is repeated repeatedly and the layers are stacked to finally form the desired three-dimensional structure.

[0105] For example, in step (f), the microchannels are separated from the glass substrate 8 by ablation of the metal sacrificial layer 9 through the glass substrate 8 using a laser.

[0106] Specifically, step (2) includes: first, combining the side of the interlayer heat dissipation microchannel with the micro heat sink with the first radio frequency functional layer 01, and then combining the side of the interlayer heat dissipation microchannel without the micro heat sink with the second radio frequency functional layer 02 to form a three-dimensional radio frequency microsystem.

[0107] The following specific embodiments further illustrate the three-dimensional radio frequency microsystem and its fabrication method of the present invention.

[0108] In the following embodiments, the heat dissipation performance testing method is as follows: Since directly testing the heat dissipation of the three-dimensional radio frequency microsystem is not easy to implement, and the heat dissipation effect of the three-dimensional radio frequency microsystem is achieved by the interlayer heat dissipation microchannels, this invention directly tests the heat dissipation effect of the interlayer heat dissipation microchannels to indirectly prove the heat dissipation performance of the interlayer heat dissipation microchannels on the three-dimensional radio frequency microsystem. Specifically, as shown in the following embodiments... Figure 14 As shown, a substrate 11 is bonded to one side of the interlayer heat dissipation microchannel where a micro heat sink is provided. Then, a thermal test chip 12 is embedded in the substrate 11. The thermal test chip 12 is in contact with the micro heat sink. Power is supplied to the thermal test chip 12 through the substrate 11. The difference in applied power per unit area required for the thermal test chip 12 to reach the same temperature before and after the addition of the interlayer heat dissipation microchannel (cooling medium is water) is detected. This difference is the heat dissipation capacity of the interlayer heat dissipation microchannel, which is the heat dissipation capacity of the three-dimensional radio frequency microsystem.

[0109] Example 1

[0110] This embodiment provides a three-dimensional radio frequency (RF) microsystem, including multiple RF functional layers and interlayer heat dissipation microchannels. The interlayer heat dissipation microchannels include 3D-printed microchannels and micro-heat sinks 3 disposed within the 3D-printed microchannels; the 3D-printed microchannels are made of resin. The interlayer heat dissipation microchannels are disposed between two adjacent RF functional layers, with the RF functional layer to be cooled contacting the side of the interlayer heat dissipation microchannel where the micro-heat sink 3 is disposed. The RF functional layers include a first RF functional layer 01 and a second RF functional layer 02. The first RF functional layer 01 contacts the side of the interlayer heat dissipation microchannel where the micro-heat sink 3 is disposed, and a chip 03 is disposed in the first RF functional layer 01. An antenna 04 is disposed on the upper surface of the first RF functional layer 01, meaning the first RF functional layer 01 is an integrated RF microsystem with an antenna. The micro-heat sinks 3 are disposed in a one-to-one correspondence with the chips 03. The second RF functional layer 02 is a filter. The second RF functional layer 02 is provided with ports respectively connected to the cooling medium inlet 5 and the cooling medium outlet 6 in the interlayer heat dissipation microchannels. The first RF functional layer 01 and the second RF functional layer 02 are interconnected by solder balls 05. The solder balls 05 penetrate the interlayer heat dissipation microchannel between the first RF functional layer 01 and the second RF functional layer 02. The solder balls 05 interconnect the first RF functional layer 01 and the second RF functional layer 02 through the solder ball placement area of ​​the interlayer heat dissipation microchannel. The chip 03, antenna 04, and solder balls 05 are interconnected by metal wires. The interlayer heat dissipation microchannel is connected to the RF functional layer by adhesive. The adhesive is TIM adhesive.

[0111] The interlayer heat dissipation microchannel includes a microchannel layer 1, a cover plate layer 2, and a micro heat sink 3; both the microchannel layer 1 and the cover plate layer 2 are made of resin; the micro heat sink 3 is disposed in the microchannel layer 1, and the microchannel layer 1, the micro heat sink 3, and the cover plate layer 2 form a flow channel 4 for the flow of cooling medium. The microchannel layer 1 and the cover plate layer 2 are manufactured by 3D printing.

[0112] The micro heat sink 3 has multiple fins 301 on the side near the cover plate layer 2, and the multiple fins 301 are located in the flow channel 4. The fins 301 are cubic blocks, and the cubic blocks of fins 301 are distributed in a matrix on the side of the micro heat sink 3 near the cover plate layer 2.

[0113] The distance between adjacent fins 301 is 300 μm. The side length of the cross section of the fin 301 facing the cover plate layer 2 is equal to the distance between adjacent fins 301. The length of the fin 301 extending from away from the cover plate layer 2 towards the cover plate layer 2 is 120 μm. The thickness of the flow channel 4 is 140 μm.

[0114] The side of the micro heat sink 3 away from the cover plate layer 2 is flush with the side of the microchannel layer 1 away from the cover plate layer 2.

[0115] The connection surface between the micro heat sink 3 and the microchannel layer 1 is stepped. The connection surface between the microchannel layer 1 and the micro heat sink 3 forms a stepped connection surface with a downward staircase from the side of the microchannel layer 1 away from the cover plate layer 2 to the side of the microchannel layer 1 closer to the cover plate layer 2.

[0116] The material of the micro heat sink 3 is copper.

[0117] The overall thickness of the interlayer heat dissipation microchannel is 420 μm. Among them, the thickness of the cover plate layer 2 is 120 μm, and the thickness of the microchannel layer 1 is 160 μm.

[0118] The cover plate layer 2 is provided with a cooling medium inlet 5 and a cooling medium outlet 6. The flow channel 4 includes multiple sub-flow channels extending from the cooling medium inlet 5 to the cooling medium outlet 6, with each sub-flow channel connected to the cooling medium inlet 5 and the cooling medium outlet 6 at both ends, respectively. The non-flow channel area of ​​the interlayer heat dissipation microchannel is provided with a solder ball placement area 7.

[0119] The heat dissipation capacity of the three-dimensional radio frequency microsystem in this embodiment is 850W / cm². 2 .

[0120] Example 2

[0121] This embodiment provides a method for fabricating a three-dimensional radio frequency microsystem according to Embodiment 1, including:

[0122] Step (1): Combine the micro heat sink with the 3D printing platform, and 3D print microchannels around the micro heat sink to obtain interlayer heat dissipation microchannels; specifically including:

[0123] Step (a): A metal sacrificial layer 9 is formed on one side of a glass substrate 8 by FHR magnetron sputtering; the metal sacrificial layer 9 is made of Cu.

[0124] Step (b): Attach the other side of the glass substrate 8 to the 3D printing platform 10 by adhesive.

[0125] Step (c): The micro heat sink 3 is bonded to the glass substrate 8 by adhesive bonding.

[0126] Step (d): Print the microchannel layer 1 and the cover plate layer 2 in sequence; when printing the cover plate layer 2, reserve the cooling medium inlet 5 and the cooling medium outlet 6; during 3D printing, reserve the solder ball placement area 7 in the non-channel area of ​​the interlayer heat dissipation microchannel.

[0127] Step (e): Separate the glass substrate 8 from the 3D printing platform 10;

[0128] Step (f): The microchannels are separated from the glass substrate 8 by ablation of the metal sacrificial layer 9 through the glass substrate 8 with a laser, thus obtaining the interlayer heat dissipation microchannels.

[0129] Step (2): First, combine the side of the interlayer heat dissipation microchannel with the micro heat sink with the first radio frequency functional layer 01, and then combine the side of the interlayer heat dissipation microchannel without the micro heat sink with the second radio frequency functional layer 02 to form a three-dimensional radio frequency microsystem.

[0130] Example 3

[0131] This embodiment provides a three-dimensional radio frequency microsystem similar to that of Embodiment 1, except that the connection surface between the micro heat sink 3 and the microfluidic layer 1 is planar.

[0132] The water tightness of the three-dimensional radio frequency microsystem in this embodiment is less than that in Embodiment 1.

[0133] Example 4

[0134] This embodiment provides a three-dimensional radio frequency microsystem similar to Embodiment 1, except that the connection surface between the microchannel layer and the microheat sink forms a stepped connection surface that extends from the side of the microchannel layer away from the cover plate layer to the side of the microchannel layer closer to the cover plate layer.

[0135] The heat dissipation capacity of the three-dimensional radio frequency microsystem in this embodiment is 734W / cm². 2 .

[0136] Example 5

[0137] This embodiment provides a three-dimensional radio frequency microsystem similar to that of Embodiment 1, except that the length of the fins is 80 μm.

[0138] The heat dissipation capacity of the three-dimensional radio frequency microsystem in this embodiment is 698W / cm². 2 .

[0139] Example 6

[0140] This embodiment provides a three-dimensional radio frequency microsystem similar to that of Embodiment 1, except that the length of the fins is 50 μm and the thickness of the flow channel 4 is 70 μm.

[0141] The heat dissipation capacity of the three-dimensional radio frequency microsystem in this embodiment is 557W / cm². 2 .

[0142] Example 7

[0143] This embodiment provides a three-dimensional radio frequency microsystem similar to Embodiment 1, except that the micro heat sink is not set in a one-to-one correspondence with the chip, but is set below the two chips.

[0144] The heat dissipation capacity of the three-dimensional radio frequency microsystem in this embodiment is 412W / cm². 2 .

[0145] 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 changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-dimensional radio frequency microsystem, characterized in that, The three-dimensional radio frequency microsystem includes multiple radio frequency functional layers and interlayer heat dissipation microchannels. The interlayer heat dissipation microchannels include 3D printed microchannels and micro heat sinks disposed in the 3D printed microchannels. The 3D printed microchannels are made of resin. The interlayer heat dissipation microchannel is an independent microchannel. The interlayer heat dissipation microchannel is set between two adjacent radio frequency functional layers. The radio frequency functional layer to be dissipated is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is set. The non-channel region of the interlayer heat dissipation microchannel is provided with a solder ball placement area, which penetrates the upper and lower surfaces of the interlayer heat dissipation microchannel; adjacent radio frequency functional layers are interconnected by solder balls, which penetrate the interlayer heat dissipation microchannel between adjacent radio frequency functional layers, and the solder balls interconnect adjacent radio frequency functional layers through the solder ball placement area. The interlayer heat dissipation microchannel includes a microchannel layer, a cover plate layer, and a micro heat sink. The side of the micro heat sink away from the cover plate layer is flush with the side of the microchannel layer away from the cover plate layer. The connection surface between the micro heat sink and the microchannel layer is stepped. The connection surface between the microchannel layer and the micro heat sink forms a stepped connection surface with a downward staircase from the side of the microchannel layer away from the cover plate layer to the side of the microchannel layer closer to the cover plate layer. The micro heat sink is disposed in the microchannel layer. The microchannel layer, the micro heat sink, and the cover plate layer form a flow channel for the cooling medium to flow. The micro heat sink has multiple fins on the side near the cover plate layer, and the multiple fins are located in the flow channel. The distance between adjacent fins is 100-400 μm. The side length of the cross section of the fin facing the cover plate layer is equal to the distance between adjacent fins. The length of the fin extending from away from the cover plate layer to near the cover plate layer is 50-200 μm. The thickness of the flow channel is 70-220 μm. The overall thickness of the interlayer heat dissipation microchannel is 300-500μm; The cover plate layer is provided with at least one cooling medium inlet and at least one cooling medium outlet; the flow channel includes multiple sub-flow channels extending from the cooling medium inlet to the cooling medium outlet, and the two ends of each sub-flow channel are respectively connected to the cooling medium inlet and the cooling medium outlet.

2. The three-dimensional radio frequency microsystem according to claim 1, characterized in that, The radio frequency functional layer includes a first radio frequency functional layer and a second radio frequency functional layer. The first radio frequency functional layer is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is provided. A chip is disposed in the first radio frequency functional layer.

3. The three-dimensional radio frequency microsystem according to claim 2, characterized in that, An antenna is disposed on the upper surface of the first radio frequency functional layer.

4. The three-dimensional radio frequency microsystem according to claim 2, characterized in that, The chip is a PA or a multi-functional chip.

5. The three-dimensional radio frequency microsystem according to claim 2, characterized in that, The second radio frequency functional layer is one or more of the following: filter, duplexer, radio frequency switch, mixer, and digital-to-analog converter.

6. The three-dimensional radio frequency microsystem according to claim 2, characterized in that, The second radio frequency functional layer is provided with ports that are respectively connected to the inlet and outlet of the interlayer heat dissipation microchannel.

7. The three-dimensional radio frequency microsystem according to claim 1, characterized in that, The interlayer heat dissipation microchannels are connected to the radio frequency functional layer by adhesive.

8. The three-dimensional radio frequency microsystem according to claim 7, characterized in that, The adhesive is TIM adhesive or conductive adhesive.

9. A method for fabricating a three-dimensional radio frequency microsystem, used to fabricate the three-dimensional radio frequency microsystem according to any one of claims 1-8, characterized in that, The preparation method includes: Step (1): Combine the micro heat sink with the 3D printing platform, and 3D print microchannels around the micro heat sink to obtain interlayer heat dissipation microchannels; the 3D printed microchannels are made of resin, and the interlayer heat dissipation microchannels are independent microchannels, including a microchannel layer, a cover layer and a micro heat sink, with the side of the micro heat sink away from the cover layer flush with the side of the microchannel layer away from the cover layer; the connection surface between the micro heat sink and the microchannel layer is stepped; the connection surface between the microchannel layer and the micro heat sink forms a stepped connection surface with a downward staircase from the side of the microchannel layer away from the cover layer to the side of the microchannel layer closer to the cover layer. The micro heat sink is disposed in the microchannel layer. The microchannel layer, the micro heat sink, and the cover plate layer form a flow channel for the cooling medium to flow. Multiple fins are disposed on the side of the micro heat sink near the cover plate layer, and these fins are located within the flow channel. The distance between adjacent fins is 100-400 μm. The side length of the cross-section of each fin facing the cover plate layer is equal to the distance between adjacent fins. The length of each fin extending from away from the cover plate layer towards the cover plate layer is 50-200 μm. The thickness of the flow channel is 70-220 μm. The overall thickness of the interlayer heat dissipation microchannel is 300-500 μm. The cover plate layer is provided with at least one cooling medium inlet and at least one cooling medium outlet; the flow channel includes multiple sub-flow channels extending from the cooling medium inlet to the cooling medium outlet, and each sub-flow channel is connected to the cooling medium inlet and the cooling medium outlet at both ends, respectively. The non-channel area of ​​the interlayer heat dissipation microchannel is provided with a solder ball placement area, which penetrates the upper and lower surfaces of the interlayer heat dissipation microchannel; Step (2): Combine the interlayer heat dissipation microchannel with the radio frequency functional layer. The radio frequency functional layer to be dissipated is in contact with the side of the interlayer heat dissipation microchannel where a micro heat sink is provided. The interlayer heat dissipation microchannel is provided between two adjacent radio frequency functional layers. The adjacent radio frequency functional layers are interconnected by solder balls. The solder balls penetrate the interlayer heat dissipation microchannel between the adjacent radio frequency functional layers, and the solder balls interconnect the adjacent radio frequency functional layers through the solder ball placement area.

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