A radar subarray stereoscopic stacking method and radar subarray

Abstract

The application discloses a radar subarray three-dimensional stacking method and a radar subarray, and the method comprises the following steps: placing a carrier plate provided with a radio frequency connector in an opening of a tool base; accurately aligning and stacking a subarray mother board and the carrier plate; accurately aligning and stacking a first support, a first transceiving module, a wave control module and a second transceiving module with the subarray mother board, wherein the first support is placed in the tool base and has the same height as the subarray mother board; accurately aligning and stacking a first antenna, a third transceiving module and a second antenna with the first transceiving module, the wave control module and the second transceiving module on the first support; accurately aligning and stacking a third antenna with the third transceiving module on a second support placed on the first support; and performing reflow soldering on the radar subarray after the stacking, and performing gas phase cleaning on the radar subarray after the soldering. The application can realize three-dimensional stacking of a multi-layer radar subarray and one-time soldering after the multi-layer stacking.

Description

Technical Field

[0001] This invention belongs to the field of radar technology, specifically relating to a method for three-dimensional stacking of radar subarrays and a radar subarray. Background Technology

[0002] As miniaturized, lightweight, and high-density "tile-type" active solid-state phased array radars have progressed from initial verification and exploration to gradual engineering applications, the traditional production and assembly processes of "brick-type" phased array radars connected by waveguides and other components are no longer fully applicable to the integration of new radar subarrays.

[0003] "Brick-type" phased array radars typically separate their antennas and transceiver modules, using waveguides for connection. This limits the radar's integration density. Furthermore, the current design density of multi-chip transceiver components in the XY direction is approaching or even exceeding manufacturability bottlenecks. "Brick-type" multi-chip transceiver components in the XY direction can no longer meet the demands of high-density, lightweight radar designs. The focus of manufacturing processes has shifted from planar assembly to three-dimensional assembly. The main difference between planar and three-dimensional assembly lies in the conversion of the connection between microwave and electrical signals from the XY direction to the Z direction. Solid-state active phased array radars contain tens of thousands of transceiver components, necessitating exploration of Z-axis integration of antennas and transceiver components in radar subarrays to achieve higher integration and meet the demands of next-generation, higher-density products.

[0004] In addition, the use of solder balls to transmit microwave and electrical signals requires high consistency of the solder balls after soldering. For multi-layer assembly and stacking using solder paste with the same melting point, integrated soldering is required to avoid repeated melting of the solder and thus achieve high reliability. Summary of the Invention

[0005] The purpose of this invention is to provide a method for three-dimensional stacking of radar subarrays and a radar subarray, which can realize the three-dimensional stacking of multi-layer radar subarrays and the one-time welding of multi-layer stacked subarrays.

[0006] One aspect of the present invention provides a method for three-dimensional stacking of radar subarrays, comprising:

[0007] Step S1: Place the RF connector onto the carrier board using solder paste, and place the carrier board with the RF connector onto the opening in the tooling base;

[0008] Step S2: Print solder paste on the carrier plate using the first solder paste stencil, and stack the sub-array motherboards after accurately aligning them with the carrier plate;

[0009] Step S3: Align the first bracket with the tooling base, ensuring the first bracket is at the same height as the subarray motherboard. Use the second solder paste stencil to print solder paste on the subarray motherboard. After accurately aligning the first transceiver module, the wave control module, and the second transceiver module with the subarray motherboard, stack them.

[0010] Step S4: Place the second bracket on the first bracket. The height of the second bracket is the same as that of the first transceiver module, the beam control module and the second transceiver module. Use the third solder paste stencil to print solder paste on the first transceiver module, the beam control module and the second transceiver module. After accurately aligning the first antenna, the third transceiver module and the second antenna with the first transceiver module, the beam control module and the second transceiver module respectively, stack them.

[0011] Step S5: Place the third bracket on the second bracket. The height of the third bracket is the same as that of the first antenna, the third transceiver module and the second antenna. Use the fourth solder paste stencil to print solder paste on the third transceiver module. After accurately aligning the third antenna and the third transceiver module, stack them.

[0012] Step S6: Perform reflow welding on the completed stacked radar subarrays, and perform vapor phase cleaning on the completed welded radar subarrays.

[0013] Preferably, the solder paste used in steps S1 to S5 is Sn63Pb37 solder paste.

[0014] Preferably, the first bracket, the second bracket, and the third bracket are made of aluminum alloy or aluminum-silicon alloy.

[0015] Preferably, in step S6, a vacuum phase welding furnace is used to perform reflow welding on the completed stacked radar subarrays.

[0016] Preferably, the peak welding temperature is 215℃±5℃ and the welding time is 60s.

[0017] Another aspect of the present invention provides a radar subarray, which is stacked using the method described above.

[0018] According to the radar subarray three-dimensional stacking method and radar subarray of the present invention described above, it is possible to realize the three-dimensional stacking of multi-layer radar subarrays and the one-time welding after multi-layer stacking. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0020] Figure 1This is a flowchart of a three-dimensional stacking method for radar subarrays according to one embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a placement of an RF connector according to one embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of printing solder paste through a first solder paste stencil according to one embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of stacking a subarray motherboard and a carrier board according to one embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of printing solder paste using a second solder paste stencil, according to one embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of stacking the first transceiver module, the beam control module, and the second transceiver module with the subarray motherboard according to one embodiment of the present invention.

[0026] Figure 7 This is a schematic diagram of printing solder paste using a third solder paste stencil, according to one embodiment of the present invention.

[0027] Figure 8 This is a schematic diagram of a first transceiver module, a beam control module, and a second transceiver module stacked together according to one embodiment of the present invention.

[0028] Figure 9 This is a schematic diagram of printing solder paste using a fourth solder paste stencil, according to one embodiment of the present invention.

[0029] Figure 10 This is a schematic diagram of stacking a third antenna and a third transceiver module according to one embodiment of the present invention.

[0030] Figure 11 This is a front view of a radar subarray according to one embodiment of the present invention.

[0031] Figure 12 This is a right view of a radar subarray according to one embodiment of the present invention.

[0032] Figure 13 This is a left view of a radar subarray according to one embodiment of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] With the development and maturation of 3D integration, and considering the current state of engineering for "W-type" active solid-state phased array radars, this invention provides a 3D stacking method for radar subarrays based on current production technology and next-generation product design. This method utilizes vertical interconnection technology to stack antennas, transceiver modules, and beam control modules in a 3D manner. This not only satisfies high-precision vertical stacking interconnection but also enables one-time welding after multi-layer stacking, thereby achieving highly reliable integration of multi-layer radar subarrays and solving the further engineering application of high-density "W-type" active solid-state phased array radars.

[0035] In the radar subarray three-dimensional stacking method of the present invention, the antenna includes a first antenna, a second antenna and a third antenna, and the transceiver module includes a first transceiver module, a second transceiver module and a third transceiver module. The subarray is stacked in such a way that the transceiver module is below the antenna, the beam control module is below the transceiver module, the radio frequency connector is below the subarray motherboard, the first antenna corresponds to the first transceiver module in vertical position, the second antenna corresponds to the second transceiver module in vertical position, and the third antenna corresponds to the third transceiver module in vertical position.

[0036] The radar subarray three-dimensional stacking method of this invention requires the prior preparation of high-precision fixtures, including carrier boards, positioning pins, steel mesh, and brackets of varying heights. The brackets can be aluminum alloy or aluminum-silicon alloy. The subarray motherboard can be FR-4 (glass fiber composite material) or LTCC (low temperature co-fired ceramic) multilayer board. The RF connector can be a soft button connection. The wave control module and transceiver module are SiP (system-in-package) with corresponding functions in the form of double-sided BGA (ball grid array). The antenna can be made of LTCC or HTCC (high temperature co-fired ceramic) material and has solderable pads.

[0037] Figure 1 This is a flowchart of a three-dimensional stacking method for radar subarrays according to one embodiment of the present invention. Figure 1 As shown, the radar subarray three-dimensional stacking method of the present invention includes steps S1-S6.

[0038] In step S1, the RF connector is placed on the carrier plate using solder paste, and the carrier plate with the RF connector is placed in the opening of the tooling base.

[0039] like Figure 2As shown, in this step, the fixture base 12 is first prepared. The fixture base 12 has four locating pins of precise dimensions for positioning the fixture base 12. After the RF connector 2 is coated with Sn63Pb37 solder paste, it is placed on the carrier board 1. Then, the carrier board 1 with the RF connector 2 is placed at the opening of the fixture base 12.

[0040] In step S2, solder paste is printed on the carrier plate using the first solder paste stencil, and the subarray motherboard is stacked after being accurately aligned with the carrier plate.

[0041] like Figure 3 As shown, in this step, a first solder paste stencil Q13 and Sn63Pb37 solder paste are prepared. After aligning the first solder paste stencil Q13 with the tooling base 12 as shown in the figure, Sn63Pb37 solder paste is printed on the carrier plate 1 through the first solder paste stencil Q13. After printing, the first solder paste stencil Q13 is removed.

[0042] After the subarray motherboard 4 is accurately aligned with the carrier board 1 using a semi-automatic placement machine, it is stacked with the carrier board 1 to complete the first stacking. Figure 4 As shown.

[0043] In step S3, the first bracket is aligned with the tooling base and the height of the first bracket is the same as that of the subarray motherboard. Solder paste is printed on the subarray motherboard using the second solder paste stencil. After the first transceiver module, the wave control module and the second transceiver module are accurately aligned with the subarray motherboard, they are stacked.

[0044] like Figure 5 As shown, in this step, the second solder paste stencil 14 and the first support 15, as well as Sn63Pb37 solder paste, are prepared. The first support 15 is aligned with the tooling base 12, and the height of the first support 15 is the same as that of the subarray motherboard 4. Then, the second solder paste stencil 14 is placed on the first support 15 according to the positioning marks. Sn63Pb37 solder paste is printed on the subarray motherboard 4 through the second solder paste stencil 14. After printing, the second solder paste stencil 14 is removed.

[0045] The first transceiver module 5, the beam control module 6, and the second transceiver module 7 are accurately aligned with the subarray motherboard 4 using a semi-automatic chip mounter, and then stacked with the subarray motherboard 4 to complete the second stacking. Figure 6 As shown.

[0046] In step S4, a second bracket is placed on the first bracket. The second bracket is at the same height as the first transceiver module, the beam control module, and the second transceiver module. Solder paste is printed on the first transceiver module, the beam control module, and the second transceiver module using a third solder paste stencil. The first antenna, the third transceiver module, and the second antenna are stacked after being accurately aligned with the first transceiver module, the beam control module, and the second transceiver module, respectively.

[0047] like Figure 7 As shown, in this step, the third solder paste stencil 16 and the second bracket 17, as well as Sn63Pb37 solder paste, are prepared. The second bracket 17 is aligned with the tooling base 12 and placed on the first bracket 15. The height of the second bracket 17 is consistent with that of the first transceiver module 5, the wave control module 6, and the second transceiver module 7. The third solder paste stencil 16 is then placed on the second bracket 17 according to the positioning marks. Sn63Pb37 solder paste is printed on the first transceiver module 5, the wave control module 6, and the second transceiver module 7 through the third solder paste stencil 16. After printing, the third solder paste stencil 16 is removed.

[0048] The first antenna 8, the third transceiver module 9, and the second antenna 10 are accurately aligned with the first transceiver module 5, the beam control module 6, and the second transceiver module 7 respectively using a semi-automatic chip mounter. Then, they are stacked with the first transceiver module 5, the beam control module 6, and the second transceiver module 7 to complete the third stacking. Figure 8 As shown.

[0049] In step S5, a third bracket is placed on the second bracket. The height of the third bracket is the same as that of the first antenna, the third transceiver module and the second antenna. Solder paste is printed on the third transceiver module using a fourth solder paste stencil. After the third antenna and the third transceiver module are accurately aligned, they are stacked.

[0050] like Figure 9 As shown, in this step, prepare the fourth solder paste stencil 18 and the third bracket 19, as well as Sn63Pb37 solder paste. Align the third bracket 19 with the tooling base 12 and place the third bracket 19 on the second bracket 17. The height of the third bracket 19 should be consistent with that of the first antenna 8, the third transceiver module 9, and the second antenna 10. Then, place the fourth solder paste stencil R18 on the third bracket 19 according to the positioning marks. Print Sn63Pb37 solder paste on the third transceiver module 9 through the fourth solder paste stencil 18. After printing, remove the fourth solder paste stencil 18.

[0051] After the third antenna 11 is accurately aligned with the third transceiver module 9 using a semi-automatic patch panel, it is stacked with the third transceiver module 9 to complete the fourth stacking. Figure 10 As shown.

[0052] In step S6, the stacked radar subarrays are reflow welded, and the welded radar subarrays are vapor-phase cleaned.

[0053] In this step, the stacked subarrays are placed in a vacuum phase welding furnace for reflow soldering. The peak welding temperature is 215℃±5℃, and the time is 60s. Microscopic and X-ray inspections are used to check whether the welded products meet production inspection requirements. Subsequently, the entire welded subarray is placed in a vapor phase cleaning machine to remove flux and excess material from the welding process, resulting in the desired product. Figures 11-13 The radar subarray shown is a three-dimensional stacked and integrated array.

[0054] Following the above production process, the integrated integration of multi-layer radar subarrays can be completed, thereby realizing the integrated welding and assembly of microwave hybrid SiP modules, antennas, and wave control modules on the Z-axis, thus meeting the requirement of low-cost integrated three-dimensional integration.

[0055] In summary, the radar subarray three-dimensional stacking method of this invention, through the matching design and application of multi-layer fixtures and combined with high-precision tooling positioning, completes the printing and stacking of the same solder paste at different heights and modules in stages, thereby achieving three-dimensional stacking and integrated integration of multi-layer radar subarrays. This improves the manufacturability of highly integrated radars, reduces production scrap rates, and minimizes the reliability impact of multiple, repeated soldering on solder joints, meeting the requirements of aerospace-grade microwave hybrid integrated production processes. Furthermore, by vertically interconnecting antennas, transceiver modules, wave control modules, subarray motherboards, and carrier boards, the three-dimensional integration of the radar subarray is maximized while meeting the needs of miniaturization, lightweighting, and high-density design and development. Moreover, by flexibly employing stencil printing technology, chip stacking technology, reflow soldering technology, and vapor phase cleaning technology, high-precision solder paste printing and stacking are achieved on the carrier board, subarray motherboard, wave control module, and transceiver module at matching heights. After stacking, a reflow soldering furnace is used for welding, and vapor phase cleaning is used to clean the subarray, thereby achieving integrated integration of multi-layer radar subarrays.

[0056] The embodiments of the present invention also provide a radar subarray, which is obtained by stacking radar subarrays using the three-dimensional stacking method of the embodiments of the present invention. Figures 11-13 These are, respectively, a front view, a right view, and a left view of a radar subarray according to one embodiment of the present invention. Figures 11-13 As shown, a radar subarray according to one embodiment of the present invention includes a carrier board 1, an RF connector 2, a subarray motherboard 4, a first transceiver module 5, a beam control module 6, a second transceiver module 7, a first antenna 8, a third transceiver module 9, a second antenna 10, and a third antenna 11. The RF connector 2 is placed in the carrier board 1, the subarray motherboard 4 is stacked on the carrier board 1, the first transceiver module 5, the beam control module 6, and the second transceiver module 7 are stacked on the subarray motherboard 4, the first antenna 8, the third transceiver module 9, and the second antenna 10 are respectively stacked on the first transceiver module 5, the beam control module 6, and the second transceiver module 7, and the third antenna 11 is stacked on the third transceiver module 9.

[0057] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for three-dimensional stacking of radar subarrays, characterized in that, include: Step S1: Place the RF connector onto the carrier board using solder paste, and place the carrier board with the RF connector onto the opening in the tooling base; Step S2: Print solder paste on the carrier plate using the first solder paste stencil, and stack the sub-array motherboards after accurately aligning them with the carrier plate; Step S3: Align the first bracket with the tooling base, ensuring the first bracket is at the same height as the subarray motherboard. Use the second solder paste stencil to print solder paste on the subarray motherboard. After accurately aligning the first transceiver module, the wave control module, and the second transceiver module with the subarray motherboard, stack them. Step S4: Place the second bracket on the first bracket. The height of the second bracket is the same as that of the first transceiver module, the beam control module and the second transceiver module. Use the third solder paste stencil to print solder paste on the first transceiver module, the beam control module and the second transceiver module. After accurately aligning the first antenna, the third transceiver module and the second antenna with the first transceiver module, the beam control module and the second transceiver module respectively, stack them. Step S5: Place the third bracket on the second bracket. The height of the third bracket is the same as that of the first antenna, the third transceiver module and the second antenna. Use the fourth solder paste stencil to print solder paste on the third transceiver module. After accurately aligning the third antenna and the third transceiver module, stack them. Step S6: Perform reflow welding on the completed stacked radar subarrays, and perform vapor phase cleaning on the completed welded radar subarrays.

2. The method as described in claim 1, characterized in that, The solder paste used in steps S1 to S5 is Sn63Pb37 solder paste.

3. The method as described in claim 1 or 2, characterized in that, The first bracket, the second bracket, and the third bracket are made of aluminum alloy.

4. The method as described in claim 1 or 2, characterized in that, In step S6, the stacked radar subarrays are reflow welded using a vacuum phase welding furnace.

5. The method as described in claim 4, characterized in that, The peak welding temperature was 215℃±5℃, and the welding time was 60s.

6. A radar subarray, characterized in that, It is obtained by stacking using any one of claims 1-5.

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