Double-ridge waveguide cavity printed circuit board

Abstract

The utility model is suitable for the circuit board field, and provides a double-ridge waveguide cavity printed circuit board comprising a circuit board, the circuit board is provided with a plurality of double-ridge waveguide cavity slots and a plurality of area through holes, and the surfaces of the circuit board, the double-ridge waveguide cavity slots and the area through holes are all provided with copper plating layers. And oil plugging hole resin is arranged in the regional through hole. According to the utility model, the regional through holes are changed into blind holes from the first layer to the seventh layer by adopting back etching and plasma degumming methods, so that stubs from the seventh layer to the eighth layer of the regional through holes added with oil plugging hole resin are covered by solder resist ink after silk-screen solder resist, short circuit in assembly is avoided, and the production efficiency is improved. And the area through hole covered with the solder resist ink is lower than the surface of the copper plating layer at the double-ridge waveguide cavity slot hole of the 3D waveguide antenna mounting area, so that the packaging of the 3D waveguide antenna and the waveguide packaging chip is not influenced, and the problem that the mounting flatness of the 3D waveguide antenna is influenced by the protrusion after the hole is plugged by resin is effectively solved.

Description

Technical Field

[0001] The utility model belongs to the field of circuit boards, and in particular relates to a double-ridge waveguide cavity printed circuit board. Background Art

[0002] With the continuous application of millimeter-wave radar in advanced driver assistance systems, the Internet of Things, drones, security, sports and other industries, millimeter-wave radar systems have also ushered in very rapid development, and 3D waveguide antennas are also being used more and more widely in the field of automotive radar.

[0003] However, the complex application environment and increasingly high performance parameter requirements have created an irreconcilable contradiction between the cost and miniaturization requirements of 3D waveguide antennas. Traditional circuit boards cannot meet the precise installation requirements of 3D waveguide antennas, and new circuit boards are needed to improve manufacturing accuracy and efficiency.

[0004] In order to avoid the above technical problems, it is necessary to provide a double-ridge waveguide cavity printed circuit board to overcome the above defects in the prior art. Summary of the invention

[0005] The utility model aims to provide a double-ridge waveguide cavity printed circuit board, aiming to solve the problem that traditional circuit boards cannot meet the precise installation requirements of 3D waveguide antennas.

[0006] The utility model is implemented as follows: a double-ridge waveguide cavity printed circuit board comprises a circuit board, wherein a plurality of double-ridge waveguide cavity slots and a plurality of regional through holes are provided on the circuit board, the circuit board, the double-ridge waveguide cavity slots and the regional through holes are provided with a copper plating layer on their surfaces, an oil plugging hole resin is provided inside the regional through holes, a degumming hole is provided at one end of the oil plugging hole resin, a circuit is etched on the copper plating layer to form a back-etching groove, the back-etching groove is connected to the degumming hole, and a solder resist ink is provided inside the back-etching groove to avoid a short circuit.

[0007] According to a further technical solution, the circuit board is formed by thermally pressing two copper foils, three high Tg FR-4 core boards and four high Tg FR-41080 adhesive sheets.

[0008] According to a further technical solution, the thickness of the degumming hole is 0.03 mm.

[0009] According to a further technical solution, the thickness of the back-etched groove is 0.05 mm.

[0010] According to a further technical solution, the top of the solder resist ink is lower than the top of the copper plating layer.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] A double-ridged waveguide cavity printed circuit board provided by an embodiment of the utility model realizes that the regional through holes are converted into blind holes of the 1st to 7th layers by adopting the methods of back etching and plasma degumming, ensuring that after silk screen solder mask is printed and the residual piles of the 7th to 8th layers of the regional through holes after adding the oil hole plugging resin are covered with solder mask ink, ensuring that there is no short circuit in the assembly, and the regional through holes covered with solder mask ink are lower than the copper plating layer surface at the double-ridged waveguide cavity slot hole in the 3D waveguide antenna installation area, and do not affect the packaging of the 3D waveguide antenna and the waveguide package chip, effectively solving the problem of bulging after resin plugging and thus affecting the installation flatness of the 3D waveguide antenna. This method improves the manufacturing accuracy and efficiency of the circuit board and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the cross-sectional structure of the circuit board in step 1 of the utility model;

[0014] Figure 2 It is a schematic diagram of the cross-sectional structure of the double-ridge waveguide cavity slot and the regional through hole in step 2 and step 3 of the utility model;

[0015] Figure 3 A top view of the long slot hole of the double-ridged waveguide cavity, the short slot hole of the double-ridged waveguide cavity, and the arc of the angle between the long and short slot holes of the double-ridged waveguide cavity in step 2 of the present invention;

[0016] Figure 4 It is a schematic diagram of the cross-sectional structure in which only the eighth layer of oil hole plugging resin is exposed in step 6 of the present invention;

[0017] Figure 5 It is a schematic diagram of the cross-sectional structure of removing the resin plugging the oil holes of the circuit board in step 7 of the present invention;

[0018] Figure 6 It is a schematic diagram of the cross-sectional structure of the blind holes from the 1st layer to the 7th layer in step 9 of the utility model;

[0019] Figure 7 It is a schematic diagram of the cross-sectional structure in which the residual piles from the 7th layer to the 8th layer are covered by the solder resist ink in step 10 of the present invention;

[0020] Figure 8 It is a top view of the 8th layer after all the processes of the circuit board of the utility model are completed;

[0021] Fig. 9 This is a schematic diagram of completing the packaging of a 3D waveguide antenna and a waveguide packaging chip of the utility model;

[0022] In the attached drawings: 1. circuit board; 2. double-ridged waveguide cavity slot; 3. regional through hole; 4. double-ridged waveguide cavity long slot; 5. double-ridged waveguide cavity short slot; 6. arc of the included angle of the long and short slots of the double-ridged waveguide cavity; 7. oil plugging hole resin; 8. glue removal hole; 9. back etch groove; 10. solder mask ink; 11. 3D waveguide antenna; 12. waveguide packaging chip; 13. copper plating layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0024] The specific implementation of the present utility model is described in detail below in conjunction with specific embodiments.

[0025] like Figure 1-9 As shown, a method for processing a double-ridge waveguide cavity printed circuit board provided by the utility model comprises the following steps:

[0026] (1) Two copper foils, three high Tg FR-4 core boards and four high Tg FR-4 1080 bonding sheets are thermally pressed together to form a conventional 8-layer circuit board 1 that meets the processing requirements, such as Figure 1 As shown in the figure, from top to bottom, it is the 1st to 8th layer, among which the 8th layer is the 3D waveguide antenna installation surface; (Tg is the glass transition temperature, that is, the glass transition temperature (which has the greatest impact on the vias). The glass transition temperature is a property of the polymer, which refers to the temperature at which the resin changes from hard (glassy state) to soft (rubbery state); FR-4 is a code for a flame retardant material grade, which means that the resin material must be able to extinguish itself after burning. It is not a material name, but a material grade. Therefore, there are many types of FR-4 grade materials used in general circuit boards 1, but most of them are composite materials made of so-called four-function (Tera-Function) epoxy resin plus filler (Filler) and glass fiber.)

[0027] (2) If Figure 2 and Figure 3 As shown, a slot drill and a gong cutter are used to drill slots on a circuit board 1 to form a double-ridge waveguide cavity slot 2. The slot drill is used to drill a long slot 4 of the double-ridge waveguide cavity, and the gong cutter is used to drill two short slots 5 of the double-ridge waveguide cavity and an included angle arc 6 of the long and short slots of the double-ridge waveguide cavity (wherein the diameter of the slot drill is 0.075 mm larger than the finished size after electroplating, and the diameter of the gong cutter is 0.05 mm larger than the finished size after electroplating).

[0028] (3) Drilling a regional through hole 3 of the circuit board 1 using a common drill bit;

[0029] (4) Deburring and performing copper-plating on the circuit board 1;

[0030] (5) copper plating is performed on the surface of the regional through hole 3 on the circuit board 1 to form a copper plating layer 13 on the surface of the circuit board 1, and then resin plugging is performed, that is, filling the regional through hole 3 with oil plugging resin 7;

[0031] (6) Figure 4 As shown, the pattern transfer is performed on the circuit board 1, and only the plugging hole resin 7 of the 8th layer of the circuit board 1 is exposed. The pattern transfer etching window is 0.05mm smaller than the completed hole to ensure that the copper plating layer 13 in the regional through hole 3 is not exposed when the window is opened;

[0032] (7) Figure 5 As shown, a plasma debonding process is used to remove the oil plugging hole resin 7 of the circuit board 1 of about 0.03 mm, forming a debonding hole 8;

[0033] (8) Laminating, exposing and developing the circuit board 1, wherein the through hole 3 in the area where the 3D waveguide antenna is installed is not exposed;

[0034] (9) Figure 6 As shown, a circuit is etched on the circuit board 1. During etching, the etching rate is controlled, and the 8th layer pad and the copper plating layer 13 from the 7th layer to the 8th layer are back-etched by about 0.05 mm to form a back-etched groove 9, so that the regional through hole 3 becomes a blind hole from the 1st layer to the 7th layer;

[0035] (10) Figure 7 As shown, the circuit board 1 is screen-printed with solder mask to ensure that the debonding holes 8 and the back-etching grooves 9 of the 7th to 8th layers of the regional through hole 3 are covered with the solder mask ink 10 to ensure that no short circuit occurs when the 3D waveguide antenna 11 and the waveguide package chip 12 are assembled, and the top plate of the solder mask ink 10 is about 0.01 mm lower than the top of the copper plating layer 13;

[0036] (11) Figure 8 and Fig. 9 As shown, the circuit board 1 is surface treated, and all processing steps of the circuit board 1 are completed to finally form the double-ridge waveguide cavity printed circuit board 1 of the utility model, and finally the 3D waveguide antenna 11 and the waveguide packaging chip 12 are packaged.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0038] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A double-ridge waveguide cavity printed circuit board, comprising a circuit board, characterized in that: The circuit board is provided with a plurality of double-ridge waveguide cavity slots and a plurality of regional through holes. The surfaces of the circuit board, the double-ridge waveguide cavity slots and the regional through holes are all provided with a copper plating layer. An oil plugging hole resin is provided inside the regional through hole. A degumming hole is provided at one end of the oil plugging hole. A back etch groove is etched on the copper plating layer. The back etch groove is connected with the degumming hole. A solder resist ink is provided inside the back etch groove.

2. The double-ridge waveguide cavity printed circuit board according to claim 1, characterized in that: The circuit board is formed by thermally pressing two copper foils, three high Tg FR-4 core boards and four high Tg FR-4 1080 bonding sheets.

3. The double-ridge waveguide cavity printed circuit board according to claim 1, characterized in that: The thickness of the debonding hole is 0.03 mm.

4. The double-ridge waveguide cavity printed circuit board according to claim 1, characterized in that: The thickness of the back-etched groove is 0.05 mm.

5. The double-ridge waveguide cavity printed circuit board according to any one of claims 1 to 4, characterized in that: The top of the solder resist ink is lower than the top of the copper plating layer.

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