Embedded PCBA module

Abstract

An embedded PCBA module comprises a ceramic substrate microwave filter and a multi-layer microwave printed board, the multi-layer microwave printed board is provided with a blind groove and board end radio frequency transmission lines, the blind groove is consistent with the ceramic substrate microwave filter in shape and size, the bottom of the blind groove is provided with a grounded copper layer, and the board end radio frequency transmission lines are printed on board surfaces on two sides of the blind groove; the ceramic substrate microwave filter is embedded in the blind groove and is flush with the upper surface of the multi-layer microwave printed board, a ground layer on the bottom surface of the ceramic substrate microwave filter is in contact with the ground of the multi-layer microwave printed board in a fitting manner, and the ceramic substrate microwave filter is provided with a first radio frequency transmission port and a second radio frequency transmission port which extend to the edge of the filter; and the first radio frequency transmission port and the second radio frequency transmission port are respectively connected with adjacent board end radio frequency transmission lines through signal connecting pieces. According to the utility model, parasitic parameters are reduced through a plurality of measures, so that the normal operation of products is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of microwave circuits, and particularly relates to an embedded PCBA module. Background Art

[0002] PCBA is the abbreviation of Printed Circuit Board Assembly in English, which is a PCB board with components soldered. The PCB blank board is assembled with components through SMT process or DIP process. Both SMT and DIP are ways to integrate components on the PCB board. SMT (Surface Mounted Technology), surface mount technology, mainly uses a mounter to mount some micro-miniature components on the PCB board.

[0003] In microwave circuits, since the band-pass filter is very sensitive to processing accuracy, the general PCB etching process is difficult to meet the requirements. Therefore, a ceramic substrate microwave filter using a thin-film process is usually used in planar circuits. Since the ceramic substrate filter using the thin-film process can only be suitable for using a single-layer ceramic substrate at present and cannot be laminated with a common PCB, at home and abroad, the ceramic substrate microwave filter 2 is assembled on the PCB board 1 in a surface-mounting manner (i.e., SMT method), and then the ceramic substrate microwave filter 2 is welded to the pads on the PCB board by a half-hole process. The current SMT installation form of the surface-mount microwave filter is as Figure 1 shown. In order to ensure the performance of the filter, generally, a separate shielding cover 3 needs to be made for the filter.

[0004] When the ceramic substrate microwave filter is assembled and welded with the PCB board, the half-hole will introduce inductive parasitic parameters, which will affect the input and output parameters of the filter for the control of tin, welding accuracy, etc.; the positioning of the filter during welding and the amount of tin during welding will also bring parasitic parameter problems. Moreover, there is an obvious height difference between the ceramic substrate microwave filter surface-mounted on the PCB board and the PCB board, which will also bring parasitic parameters. Content of the Utility Model

[0005] The purpose of the utility model is to provide an embedded PCBA module, which embeds the ceramic substrate microwave filter into the blind groove of the multi-layer microwave printed board in an embedded lamination manner, and connects the RF transmission line of the multi-layer microwave printed board and the RF transmission port of the ceramic substrate microwave filter by means of a connecting piece, so as to reduce the parasitic parameters of the product and ensure the normal operation of the product.

[0006] To achieve the above object, the technical solution adopted by the present utility model is: an embedded PCBA module, including a ceramic substrate microwave filter and a multilayer microwave printed board. The multilayer microwave printed board is provided with blind vias and board-end radio frequency transmission lines. The shape and size of the blind vias are consistent with those of the ceramic substrate microwave filter. A grounded copper layer is provided at the bottom of the blind vias. The board-end radio frequency transmission lines are printed on the board surfaces on both sides of the blind vias. The ceramic substrate microwave filter is embedded in the blind vias, and the upper surfaces of the ceramic substrate microwave filter and the multilayer microwave printed board are flush. The ground layer on the bottom surface of the ceramic substrate microwave filter is in contact with the ground of the multilayer microwave printed board. The ceramic substrate microwave filter is provided with a first radio frequency transmission port and a second radio frequency transmission port for signal transmission. Both the first radio frequency transmission port and the second radio frequency transmission port extend to the edge of the ceramic substrate microwave filter. The first radio frequency transmission port and the second radio frequency transmission port are respectively connected to the adjacent board-end radio frequency transmission lines through signal connectors.

[0007] The first radio frequency transmission port is docked with the board-end radio frequency transmission line on one side of the blind via and is in the same straight line. The second radio frequency transmission port is docked with the board-end radio frequency transmission line on the other side of the blind via and is in the same straight line.

[0008] The two board-end radio frequency transmission lines on the multilayer microwave printed board and the first radio frequency transmission port and the second radio frequency transmission port on the ceramic substrate microwave filter are in the same straight line.

[0009] As an implementation manner, the signal connector is a flip-chip ceramic through-hole device.

[0010] Further, the flip-chip ceramic through-hole device includes a ceramic substrate and a metal strip provided on the ceramic substrate. One end of the metal strip is welded to the board-end radio frequency transmission line, and the other end is welded to the first radio frequency transmission port or the second radio frequency transmission port.

[0011] Furthermore, a separation layer is also provided on the ceramic substrate, and the separation layer intersects the metal strip perpendicularly.

[0012] Still further, the separation layer is a green oil layer or a PI layer.

[0013] In this implementation manner, the bottom surface of the ceramic substrate microwave filter is bonded to the multilayer microwave printed board.

[0014] As another implementation manner, the signal connector is conductive silver paste or conductive copper paste.

[0015] Further, the resin is filled around the ceramic substrate microwave filter and on the side surfaces of the blind vias, and the resin does not exceed the upper surface of the multilayer microwave printed board.

[0016] The beneficial effects of the present utility model are as follows: The present utility model reduces the generation of parasitic parameters through various measures. (1) The ceramic substrate microwave filter is pressed into the blind via of the multilayer microwave printed circuit board by means of embedding and pressing, so that the surface of the filter and the surface of the multilayer microwave printed circuit board are on the same horizontal plane, eliminating the height difference between the two, and at the same time reducing the overall height of the product, which is convenient for the shielding cover of the filter to be integrated with the whole machine. (2) For the signal connection between the ceramic substrate microwave filter and the multilayer microwave printed circuit board, the present utility model is realized by soldering with flip-chip ceramic through connectors or connecting through resin filling the gap and conductive silver paste, reducing the parasitic parameters caused by the connection method.

[0017] In the prior art, when the ceramic substrate microwave filter is assembled and soldered with the PCB board, the accuracy requirement for the placement position of the filter is relatively high. If there is an offset between the filter and the pad, it will affect the consistency of the product performance. The present utility model adopts the embedding and pressing method, which can simplify the assembly of the ceramic substrate microwave filter and the PCB board and improve the consistency of the product performance. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0019] Figure 1 It is a schematic diagram of the installation of the surface-mounted microwave filter on the PCB in the prior art;

[0020] Figure 2 It is an exploded view of the structure of the embedded PCBA module in Embodiment 1 of the present utility model;

[0021] Figure 3 It is a schematic diagram of the structure of the flip-chip ceramic through connector in Embodiment 1 of the present utility model;

[0022] Figure 4 It is an exploded view of the structure of the embedded PCBA module in Embodiment 2 of the present utility model;

[0023] Figure 5 It is a schematic diagram of the signal connection of the embedded PCBA module in Embodiment 2 of the present utility model;

[0024] Markings in the figure: 1. PCB, 2. Ceramic substrate microwave filter, 3. Shielding cover, 4. Multilayer microwave printed board, 5. Flip-chip ceramic via, 6. Blind via, 7. Board-end RF transmission line, 8. First RF transmission port, 9. Second RF transmission port, 10. Ceramic substrate, 11. Green solder mask layer, 12. Metal strip, 13. Resin, 14. Conductive silver paste. Detailed implementation mode

[0025] The present utility model will be further described in detail below with reference to the accompanying drawings and embodiments, but it shall not be used as a basis for any limitation to the utility model.

[0026] Embodiment 1: As Figure 2 、 3 shown, an embedded PCBA module includes a multilayer microwave printed board 4, a ceramic substrate microwave filter 2, and a flip-chip ceramic via 5.

[0027] A blind via 6 with the same shape and size as the ceramic substrate microwave filter 2 is opened on the multilayer microwave printed board 4. A grounded copper layer is provided at the bottom of the blind via 6. Board-end RF transmission lines 7 are printed on the multilayer microwave printed board 4 on opposite sides of the blind via 6 for input and output of RF signals.

[0028] The ceramic substrate microwave filter 2 is embedded in the blind via 6 by a lamination method, and the upper surfaces of the ceramic substrate microwave filter 2 and the multilayer microwave printed board 4 are flush. A first RF transmission port 8 and a second RF transmission port 9 for signal transmission are provided on the upper surface of the ceramic substrate microwave filter 2. Both the first RF transmission port 8 and the second RF transmission port 9 extend to the edge of the ceramic substrate microwave filter 2. The first RF transmission port 8 is docked with the board-end RF transmission line 7 on one side of the blind via 6 and is in the same straight line. The second RF transmission port 9 is docked with the board-end RF transmission line 7 on the other side of the blind via 6 and is in the same straight line. After the ceramic substrate microwave filter 2 is laminated into the blind via 6, the ground layer on the bottom surface of the ceramic substrate microwave filter 2 is in contact with the ground of the multilayer microwave printed board 4.

[0029] Preferably, the bottom surface of the ceramic substrate microwave filter 2 is bonded to the multilayer microwave printed board 4.

[0030] The flip-chip ceramic via 5 includes a ceramic substrate 10 and a metal strip 12 located on the bottom surface of the ceramic substrate 10. The flip-chip ceramic via 5 is welded between the ceramic substrate microwave filter 2 and the multilayer microwave printed board 4. The two ends of the metal strip 12 on the flip-chip ceramic via 5 are respectively welded to the board-end RF transmission line 7 and the first RF transmission port 8 or the second RF transmission port 9 to realize signal connection.

[0031] Preferably, a solder mask layer 10 or a PI (polyimide) layer perpendicular to the metal strip 12 is provided in the middle of the metal strip 12. The setting of the solder mask layer 10 or the PI layer can prevent the solder from flowing randomly during soldering and ensure the soldering quality.

[0032] Preferably, two board-end radio frequency transmission lines 7 on the multi-layer microwave printed circuit board 4 and the first radio frequency transmission port 8 and the second radio frequency transmission port 9 on the ceramic substrate microwave filter 2 are on the same straight line.

[0033] Example 2: As Figure 4 、 5 shown, an embedded PCBA module includes a multi-layer microwave printed circuit board 4 and a ceramic substrate microwave filter 2.

[0034] A blind slot 6 with the same shape and size as the outer shape of the ceramic substrate microwave filter 2 is opened on the multi-layer microwave printed circuit board 4. A grounded copper layer is provided at the bottom of the blind slot 6. Board-end radio frequency transmission lines 7 are printed on the multi-layer microwave printed circuit board 4 on opposite sides of the blind slot 6 for input and output of radio frequency signals.

[0035] The ceramic substrate microwave filter 2 is embedded in the blind slot 6 by a pressing method, and the upper surfaces of the ceramic substrate microwave filter 2 and the multi-layer microwave printed circuit board 4 are flush. A first radio frequency transmission port 8 and a second radio frequency transmission port 9 for signal transmission are provided on the upper surface of the ceramic substrate microwave filter 2. Both the first radio frequency transmission port 8 and the second radio frequency transmission port 9 extend to the edge of the ceramic substrate microwave filter 2. The first radio frequency transmission port 8 is docked with the board-end radio frequency transmission line 7 on one side of the blind slot 6 and is on the same straight line. The second radio frequency transmission port 9 is docked with the board-end radio frequency transmission line 7 on the other side of the blind slot 6 and is on the same straight line. After the ceramic substrate microwave filter 2 is pressed into the blind slot 6, the ground layer on the bottom surface of the ceramic substrate microwave filter 2 is in contact with the ground of the multi-layer microwave printed circuit board 4.

[0036] The periphery of the ceramic substrate microwave filter 2 and the side surface of the blind slot are filled with resin 13, and the resin 13 does not exceed the upper surface of the multi-layer microwave printed circuit board 4. The signal connection between the board-end radio frequency transmission line 7 and the first radio frequency transmission port 8 is realized through conductive silver paste 14, and the signal connection between the other board-end radio frequency transmission line 7 and the second radio frequency transmission port 9 is realized through conductive silver paste 14. On the one hand, the resin can ensure the reliable embedding of the ceramic substrate microwave filter 2 in the multi-layer microwave printed circuit board 4, and on the other hand, it can provide structural support for the conductive silver paste 14.

[0037] Optionally, in other embodiments, conductive copper paste can also be used to replace the above-mentioned conductive silver paste.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those of ordinary skill in the art should understand that the specific implementation manners of the present invention can be modified or equivalently replaced by referring to the above embodiments. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention is within the protection scope of the claims pending for approval.

Claims

1. An embedded PCBA module, comprising a ceramic substrate microwave filter and a multilayer microwave printed circuit board, characterized in that: The multi-layer microwave printed circuit board is provided with blind vias and board-end radio frequency transmission lines. The shape and size of the blind vias are consistent with those of the ceramic substrate microwave filter. A grounded copper layer is provided at the bottom of the blind vias. The board-end radio frequency transmission lines are printed on the board surfaces on both sides of the blind vias. The ceramic substrate microwave filter is embedded in the blind vias, and the upper surface of the ceramic substrate microwave filter is flush with the upper surface of the multi-layer microwave printed circuit board. The ground layer on the bottom surface of the ceramic substrate microwave filter is in contact with the ground of the multi-layer microwave printed circuit board. The ceramic substrate microwave filter is provided with a first radio frequency transmission port and a second radio frequency transmission port for signal transmission. Both the first radio frequency transmission port and the second radio frequency transmission port extend to the edge of the ceramic substrate microwave filter. The first radio frequency transmission port and the second radio frequency transmission port are respectively connected to the adjacent board-end radio frequency transmission lines through signal connectors.

2. The embedded PCBA module according to claim 1, wherein: The first radio frequency transmission port is docked with the board-end radio frequency transmission line on one side of the blind via and is in the same straight line. The second radio frequency transmission port is docked with the board-end radio frequency transmission line on the other side of the blind via and is in the same straight line.

3. The embedded PCBA module according to claim 1, wherein: The two board-end radio frequency transmission lines on the multi-layer microwave printed circuit board and the first radio frequency transmission port and the second radio frequency transmission port on the ceramic substrate microwave filter are in the same straight line.

4. The embedded PCBA module according to any one of claims 1-3, characterized in that: The signal connector is a flip-chip ceramic through-hole device.

5. The embedded PCBA module according to claim 4, wherein: The flip-chip ceramic through-hole device includes a ceramic substrate and a metal strip provided on the ceramic substrate. One end of the metal strip is welded to the board-end radio frequency transmission line, and the other end is welded to the first radio frequency transmission port or the second radio frequency transmission port.

6. The embedded PCBA module according to claim 5, wherein: A separation layer is also provided on the ceramic substrate, and the separation layer intersects the metal strip perpendicularly.

7. The embedded PCBA module according to claim 6, wherein: The separation layer is a green oil layer or a PI layer.

8. The embedded PCBA module according to claim 4, characterized in that: The bottom surface of the ceramic substrate microwave filter is bonded to the multi-layer microwave printed circuit board.

9. The embedded PCBA module according to any one of claims 1-3, characterized in that: The signal connector is conductive silver paste or conductive copper paste.

10. The embedded PCBA module according to claim 9, wherein: The resin is filled around the ceramic substrate microwave filter and on the side surface of the blind via, and the resin does not exceed the upper surface of the multi-layer microwave printed circuit board.

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