Double-layer or multi-layer printed circuit board

Abstract

The utility model discloses a double-layer or multi-layer printed circuit board, which comprises a first circuit layer, a second circuit layer and a first middle layer, the first circuit layer comprises a first circuit, the second circuit layer comprises a second circuit, and at least one first connecting point is arranged between the first circuit and the second circuit. The first middle layer comprises a first insulating layer and a first bonding layer, the first insulating layer covers or is bonded on the top surface of the first circuit, and the bottom surface of the second circuit layer is bonded with the top surface of the first insulating layer through the first bonding layer; the first middle layer comprises an avoiding space of a first connecting point or a first avoiding groove corresponding to the first connecting point, and the avoiding space or the first avoiding groove comprises a first connecting body electrically connected with the second circuit and the first circuit. According to the utility model, the first circuit and the second circuit are connected through the first avoiding groove in the first intermediate layer, and in the manufacturing process of the printed circuit board, through hole drilling and through hole wall metallization are not needed, so that the manufacturing process is simple, and the manufacturing cost is relatively low.

Description

Technical Field

[0001] The utility model relates to a printed circuit board, in particular to a double-layer or multi-layer printed circuit board. Background Art

[0002] The metallized via in a double-layer or multi-layer printed circuit board is a key part for connecting circuits of different layers. The processing of the metallized via generally involves the following steps:

[0003] 1) In the printed circuit board design stage, engineers will plan the position, size and number of layers of the via. The size of the via needs to be determined according to the circuit design and connection requirements.

[0004] 2) During the printed circuit board manufacturing process, the processing of the via is usually carried out before etching. First, the printed circuit board will be cleaned to remove surface contaminants and grease to ensure the accuracy of subsequent processes.

[0005] 3) Use a drilling machine to drill a via in the substrate of the printed circuit board. The drilling machine can be a mechanical drilling machine or a laser drilling machine.

[0006] 4) After drilling, drill chips and dust will remain in the via and need to be cleaned. The cleaning process may include methods such as blowing with compressed air or ultrasonic cleaning.

[0007] 5) Via filling is to fill the drilled hole with metal to form a conductive path. The filling material is usually copper, and there are the following filling methods:

[0008] Electroplating: It is the most common filling method, and a copper layer is deposited in the via through an electrochemical process. Electroplating can be single-layer electroplating (only filling the via) or multi-layer electroplating (filling the via and connecting to the copper surface of the adjacent layer).

[0009] Electroless plating: In some cases, especially when stable performance needs to be maintained under specific conditions (such as high temperature and high humidity environment), electroless plating may be used.

[0010] 6) After filling, surface treatment may also be required, such as tin plating, gold plating, nickel plating, etc., to improve the conductive performance and prevent oxidation.

[0011] In the drilling process of traditional circuit board manufacturing, limited by the board thickness and the length of the drill bit (i.e., the aspect ratio), in order to conduct the circuits of different layers, it is necessary to first deposit copper on the hole wall and then thicken the copper layer on the hole wall by copper plating. The process flow is complex, a lot of related materials are used, and the production cost is high. Summary of the Invention

[0012] The technical problem to be solved by the present utility model is to provide a double - layer or multi - layer printed circuit board with a simple manufacturing process, and no need to drill through - holes and fill through - holes for the conduction between different layers of circuits.

[0013] To solve the above - mentioned technical problem, the technical solution adopted by the present utility model is that a double - layer or multi - layer printed circuit board includes a first circuit layer, a second circuit layer, and a first intermediate layer arranged between the first circuit layer and the second circuit layer. The first circuit layer includes a first circuit, the second circuit layer includes a second circuit, and there are at least one first connection point between the first circuit and the second circuit. The first intermediate layer includes a first insulating layer and a first adhesive layer. The first insulating layer covers or adheres to the top surface of the first circuit, the first adhesive layer covers the top surface of the first insulating layer, and the bottom surface of the second circuit layer is adhered to the top surface of the first insulating layer through the first adhesive layer; the first intermediate layer includes an avoidance space for the first connection point or a first avoidance groove corresponding to the first connection point, and a first connection body for electrically connecting the second circuit and the first circuit is included in the avoidance space or the first avoidance groove.

[0014] For the above - mentioned printed circuit board, the second circuit includes a concave body bent downward at the first connection point as the first connection body. The concave body is located in the corresponding first avoidance groove, and the bottom surface of the concave body contacts the top surface of the first circuit to form an electrical connection.

[0015] For the above - mentioned printed circuit board, a through - hole is included in the middle of the concave body, and a first conductive body is filled in the through - hole. The periphery of the first conductive body is connected to the inner wall of the through - hole, and the bottom surface of the first conductive body is connected to the top surface of the first circuit.

[0016] For the above - mentioned printed circuit board, the concave body includes a plurality of radially weakened grooves that penetrate up and down, and the plurality of radially weakened grooves are arranged in a star shape centered on the through - hole.

[0017] For the above - mentioned printed circuit board, a second conductive body corresponding to the first connection point is included as the first connection body. The second conductive body is arranged in the corresponding first avoidance groove, the bottom surface of the second conductive body is connected to the top surface of the first circuit, and the top surface of the second conductive body is connected to the bottom surface of the second circuit.

[0018] For the above - mentioned printed circuit board, it includes a third circuit layer and a second intermediate layer. The third circuit layer includes a third circuit, and there are at least one second connection point between the third circuit and the second circuit. The second intermediate layer includes a second insulating layer and a second adhesive layer. The second insulating layer covers or adheres to the top surface of the second circuit, the second adhesive layer covers the top surface of the second insulating layer, and the bottom surface of the third circuit layer is adhered to the top surface of the second insulating layer through the second adhesive layer; the second intermediate layer includes a second avoidance groove corresponding to the second connection point, and a second connection body for electrically connecting the third circuit and the second circuit is included in the second avoidance groove.

[0019] The printed circuit board described above includes a solder mask layer, and the solder mask layer includes at least one pad window; the second circuit layer or the third circuit layer is the top surface circuit layer, and the second circuit or the third circuit is the top surface circuit; the top surface circuit includes at least one pad, the solder mask layer covers the top surface circuit layer, and the pad is arranged in the corresponding pad window of the solder mask layer.

[0020] The printed circuit board described above includes a substrate and a third adhesive layer, and the bottom surface of the first circuit layer is adhered to the substrate through the third adhesive layer.

[0021] The printed circuit board described above includes a first substrate, a second substrate, a fourth adhesive layer and a fifth adhesive layer. The fourth adhesive layer is attached to the top surface of the first substrate, and the fifth adhesive layer is attached to the bottom surface of the second substrate; the bottom surface of the first circuit layer is adhered to the top surface of the first substrate through the fourth adhesive layer, and the top surface of the second circuit layer is adhered to the bottom surface of the second substrate through the fifth adhesive layer; the first circuit includes a planar coil, and the planar coil includes a planar winding, a first external connection pad and a first internal connection pad. The outer end of the planar winding is connected to the first external connection pad, and the inner end of the planar winding is connected to the first internal connection pad; the second circuit includes a jumper, a second external connection pad and a second internal connection pad. The outer end of the jumper is connected to the second external connection pad, and the inner end of the jumper is connected to the second internal connection pad; the first external connection pad and the second external connection pad are attached to form the first connection point described above, and the first internal connection pad and the second internal connection pad are attached to form the second connection point described above; the first insulating layer includes an insulating bridge, and the first adhesive layer includes an adhesive bridge. The insulating bridge is arranged between the first external connection pad and the first internal connection pad and spans the planar winding; the bottom surface of the jumper is adhered to the top surface of the insulating bridge through the adhesive bridge; the first substrate and the second substrate are pressed together and adhered through the fourth adhesive layer and the fifth adhesive layer; the first substrate and the second substrate are paper substrates, plastic substrates, resin substrates or metal substrates.

[0022] For the printed circuit board described above, the first external connection pad and the second external connection pad each include a plurality of first conductive strips arranged in parallel and communicating with each other, and the first conductive strips of the first external connection pad are orthogonal to the first conductive strips of the second external connection pad; the first internal connection pad and the second internal connection pad each include a plurality of second conductive strips arranged in parallel and communicating with each other, and the second conductive strips of the first internal connection pad are orthogonal to the second conductive strips of the second internal connection pad; the fourth adhesive layer in the gap between adjacent first conductive strips of the first external connection pad is adhered to the fifth adhesive layer in the gap between adjacent first conductive strips of the second external connection pad; the fourth adhesive layer in the gap between adjacent second conductive strips of the first internal connection pad is adhered to the fifth adhesive layer in the gap between adjacent second conductive strips of the second internal connection pad.

[0023] For the printed circuit board described above, the first external pad and the first internal pad each include a third conductive strip, and the width of the third conductive strip is smaller than the width of the second external pad and the second internal pad; the third conductive strip of the first external pad is arranged in the middle of the second external pad, and the fourth adhesive layers on both sides of the third conductive strip of the first external pad are bonded to the second external pad; the third conductive strip of the first internal pad is arranged in the middle of the second internal pad, and the fourth adhesive layers on both sides of the third conductive strip of the first internal pad are bonded to the second internal pad.

[0024] For the printed circuit board described above, the first external pad and the first internal pad each include a third conductive strip, and the second external pad and the second internal pad each include a plurality of fourth conductive strips arranged in parallel and connected to each other; the width of the third conductive strip is smaller than the length of the fourth conductive strip, the third conductive strip of the first external pad is arranged in the middle of the second external pad, the third conductive strip of the first external pad is orthogonal to the fourth conductive strip of the second external pad, the third conductive strip of the first internal pad is arranged in the middle of the second external pad, and the third conductive strip of the first internal pad is orthogonal to the fourth conductive strip of the second internal pad; the fourth adhesive layers on both sides of the third conductive strip of the first external pad are bonded to the fourth conductive strip of the second external pad; the fourth adhesive layers on both sides of the third conductive strip of the first internal pad are bonded to the fourth conductive strip of the second internal pad.

[0025] The first circuit and the second circuit of the printed circuit board of the present utility model are connected through the first avoidance groove in the first intermediate layer. During the manufacturing process of the printed circuit board, there is no need to drill through holes and metallize the through hole walls, and the manufacturing process is simple and the manufacturing cost is relatively low. [Description of Drawings]

[0026] The present utility model will be further described in detail below in conjunction with the drawings and specific embodiments.

[0027] Figure 1 It is the front view of the printed circuit board of Embodiment 1 of the present utility model.

[0028] Figure 2 It is the rear view of the printed circuit board of Embodiment 1 of the present utility model.

[0029] Figure 3 It is Figure 1 The A-A cross-sectional view in

[0030] Figure 4 It is the cross-sectional view of the printed circuit board of Embodiment 2 of the present utility model.

[0031] Figure 5 It is the cross-sectional view of the printed circuit board of Embodiment 3 of the present utility model.

[0032] Figure 6 It is Figure 5 The partial enlarged view of the I part in

[0033] Figure 7 It is a cross-sectional view of the printed circuit board in Embodiment 4 of the present utility model.

[0034] Figure 8 It is a cross-sectional view of the printed circuit board in Embodiment 5 of the present utility model.

[0035] Figure 9 It is a front view of the printed circuit board in Embodiment 6 of the present utility model.

[0036] Figure 10 It is a front view of the planar coil and the first substrate in Embodiment 6 of the present utility model.

[0037] Figure 11 It is a partial rear view of the jumper and the second substrate in Embodiment 6 of the present utility model.

[0038] Figure 12 It is a front view of the insulating bridge spanning the planar winding in Embodiment 6 of the present utility model.

[0039] Figure 13 It is Figure 9 the B-B cross-sectional view in

[0040] Figure 14 It is a front view of the planar coil and the first substrate in Embodiment 7 of the present utility model.

[0041] Figure 15 It is a front view of the jumper in Embodiment 7 of the present utility model.

[0042] Figure 16 It is a front view of the jumper in Embodiment 8 of the present utility model. [Specific Embodiments]

[0043] The structure of the printed circuit board in Embodiment 1 of the present utility model is as Figures 1 to 3 shown, including a first circuit layer 10, a second circuit layer 20 and a first intermediate layer 30. The first circuit layer 10 includes a first circuit 11, the second circuit layer 20 includes a second circuit 21, and there are a plurality of first connection points between the first circuit 11 and the second circuit 21. The first intermediate layer 30 includes a first insulating layer 31 and a first adhesive layer 32. The first insulating layer 31 covers the top surface of the first circuit 11, the first adhesive layer 32 covers the top surface of the first insulating layer 31, and the bottom surface of the second circuit layer 20 is adhered to the top surface of the first insulating layer 31 through the first adhesive layer 32. The first intermediate layer 30 includes a non-circular first avoidance groove 33 corresponding to the first connection point, and a first connection body 34 for electrically connecting the second circuit 21 and the first circuit 11 is included in the first avoidance groove 33.

[0044] In Embodiment 1, the recessed body 22 formed by locally deforming and bending downward at the first connection point of the second circuit 21 serves as the first connection body 34. The recessed body 22 is located in the corresponding first avoidance groove 33, and the bottom surface of the recessed body 22 contacts the top surface of the first circuit 11 to form an electrical connection.

[0045] In Embodiment 1, there is a through hole 23 and a plurality of radially weakened grooves 24 that penetrate up and down in the middle of the recessed body 22. The plurality of radially weakened grooves 24 are arranged in a star shape centered on the through hole 23.

[0046] The through hole 23 and the plurality of radially weakened grooves 24 that penetrate up and down are filled with a first conductive body 25. The periphery of the first conductive body 25 is connected to the inner wall of the through hole 23 and the radially weakened grooves 24, and the bottom surface of the first conductive body 25 is connected to the top surface of the first circuit 11. The first conductive body can be tin, conductive resin, or deposited copper.

[0047] The manufacturing process of the printed circuit board according to Embodiment 1 of the present utility model is as follows:

[0048] 1) The first circuit 11 of the first circuit layer 10 is fabricated on the green glue layer of the first stainless steel plate, and the second circuit 21 of the second circuit layer 20 is fabricated on the green glue layer of the second stainless steel plate;

[0049] 2) A third adhesive layer 02 is covered on the substrate 01 (refer to Embodiment 4);

[0050] 3) The first circuit 11 on the first stainless steel plate is transferred onto the third adhesive layer 02 of the substrate 01;

[0051] 4) The first intermediate layer 30 is printed on the top surface of the first circuit layer 10. First, the first insulating layer 31 is printed, and then the first adhesive layer 32 is printed. The first intermediate layer 30 includes a first avoidance groove 33 corresponding to the first connection point;

[0052] 5) The second circuit 21 on the second stainless steel plate is transferred onto the first adhesive layer 32 of the first intermediate layer 30;

[0053] 6) On a press, using an elastic indenter, the second circuit layer 20 is pressed together with the first circuit layer 10. The recessed body 22 formed by locally deforming and bending downward at the first connection point of the second circuit 21 serves as the first connection body 34 and comes into contact and conduction with the first circuit 21;

[0054] 7) Solder paste is printed on the top surface of the recessed body 22 and then heated. The tin that forms the first conductive body 25 after the solder paste melts is soldered to the first circuit 11 and the second circuit 21 respectively.

[0055] The structure of the printed circuit board according to Embodiment 2 of the present utility model is as Figure 4As shown, the difference from Embodiment 1 is that the first connector 34 is not a recessed body 22 formed by locally deforming and bending the second circuit 21 downward at the first connection point, but at the position corresponding to the first connection point, in the corresponding first avoidance groove 33, there is a second conductor 12. The bottom surface of the second conductor 12 is connected to the top surface of the first circuit 11, and the top surface of the second conductor 12 is connected to the bottom surface of the second circuit 21. The second conductor can be tin, conductive resin or deposited copper.

[0056] The structure of the printed circuit board according to Embodiment 3 of the present utility model is as Figure 5 and Figure 6 As shown, the difference from Embodiment 1 is that the first intermediate layer 30 further includes a lower adhesive layer 35 in addition to the first insulating layer 31 and the first adhesive layer 32. The lower adhesive layer 35 covers the bottom surface of the first insulating layer 31, and the bottom surface of the first insulating layer 31 is adhered to the top surface of the first circuit layer 10 through the lower adhesive layer 35. In addition, during the lamination process of the first circuit layer 10 and the second circuit layer 20, at the first connection point, the first circuit 11 and the second circuit 21 both undergo local deformation and bending, and the formed recessed body serves as the first connector 34, which are in contact and conduct electricity with each other.

[0057] The structure of the printed circuit board according to Embodiment 4 of the present utility model is as Figure 7 As shown, different from Embodiment 1, it further includes a substrate 01, a third adhesive layer 02 and a solder mask layer 40. The bottom surface of the first circuit layer 10 is adhered to the top surface of the substrate 01 through the third adhesive layer 02. The solder mask layer 40 covers the second circuit layer 20 as the top surface circuit layer, and the second circuit 21 is the top surface circuit. The solder mask layer 40 has a pad window 41 at the pad position of the corresponding second circuit 21, and the pad 26 of the second circuit 21 is arranged in the corresponding pad window 41 of the solder mask layer 40.

[0058] The structure of the printed circuit board according to Embodiment 5 of the present utility model is as Figure 8 As shown, different from Embodiment 4, it includes a third circuit layer 50 and a second intermediate layer 60. The third circuit layer 50 includes a third circuit 51, and there is at least one second connection point 52 between the third circuit 51 and the second circuit 21. The second intermediate layer 60 includes a second insulating layer 61 and a second adhesive layer 62. The second insulating layer 61 covers or adheres to the top surface of the second circuit 21, and the second adhesive layer 62 covers the top surface of the second insulating layer 61. The bottom surface of the third circuit layer 50 is adhered to the top surface of the second insulating layer 61 through the second adhesive layer 62. The second intermediate layer 60 includes a second avoidance groove 63 corresponding to the second connection point 52, and the second avoidance groove 63 includes a second connector 53 for electrically connecting the third circuit 51 and the second circuit 21. The second connector 53 can adopt the structure of the first connector 34 in Embodiment 1 or Embodiment 2.

[0059] The printed circuit board of Embodiment 5 also includes a solder mask layer 40. However, different from Embodiment 4, the solder mask layer 40 covers the third circuit layer 50 which is the top circuit layer, and the third circuit 51 is the top circuit. The solder mask layer 40 has pad windows 41 at the pad portions of the corresponding third circuits 51, and the pads 56 of the third circuits 51 are arranged in the corresponding pad windows 41 of the solder mask layer 40.

[0060] The structure of the printed circuit board of Embodiment 6 of the present utility model is as Figures 9 to 13 shown. The printed circuit board of Embodiment 6 is the circuit board of an electronic tag. Different from Embodiment 1, it further includes a first substrate 03, a second substrate 04, a fourth adhesive layer 05, and a fifth adhesive layer 06. The fourth adhesive layer 05 is attached to the top surface of the first substrate 03, and the fifth adhesive layer 06 is attached to the bottom surface of the second substrate 04. The bottom surface of the first circuit layer 10 is adhered to the top surface of the first substrate 03 through the fourth adhesive layer 05, and the top surface of the second circuit layer 20 is adhered to the bottom surface of the second substrate 04 through the fifth adhesive layer 06. The first circuit 11 includes a multi-turn planar coil. The planar coil includes a planar winding 13, a first external connection pad 14, and a first internal connection pad 15. The outer end of the planar winding 13 is connected to the first external connection pad 14, and the inner end of the planar winding 13 is connected to the first internal connection pad 15. The second circuit 21 includes a jumper 27, a second external connection pad 28, and a second internal connection pad 29. The outer end of the jumper 27 is connected to the second external connection pad 28, and the inner end of the jumper 27 is connected to the second internal connection pad 29. The first external connection pad 14 and the second external connection pad 28 are fitted together to form a first first connection point, and the first internal connection pad 15 and the second internal connection pad 29 are fitted together to form a second first connection point. The first insulating layer 31 of the first intermediate layer includes an insulating bridge 36, and the first adhesive layer 32 includes an adhesive bridge 37. The insulating bridge 36 and the adhesive bridge 37 have the same shape. The insulating bridge 36 is arranged between the first external connection pad 14 and the first internal connection pad 15, straddling and covering the planar winding 13. The bottom surface of the jumper 27 is adhered to the top surface of the insulating bridge 36 through the adhesive bridge 37. The area of the first intermediate layer outside the insulating bridge 36 (adhesive bridge 37) is the avoidance space for the two first connection points. The first substrate 03 and the second substrate 04 are press-fitted and adhered to each other through the fourth adhesive layer 05 and the fifth adhesive layer 06. The first substrate 03 and the second substrate 04 can be paper substrates, plastic substrates, resin substrates, or metal substrates. Under the action of pressure and adhesive force, the first external connection pad 14 and the second external connection pad 28 are fitted together through deformation to form a first first connection point, and the first internal connection pad 15 and the second internal connection pad 29 are fitted together through deformation to form a second first connection point.

[0061] The first external disk 14 and the second external disk 28 each include a plurality of first conductive strips 17 arranged in parallel and communicating with each other. The first conductive strips 17 of the first external disk 14 are orthogonal to and in contact with the first conductive strips 17 of the second external disk 28. The first internal disk 15 and the second internal disk 29 each include a plurality of second conductive strips 18 arranged in parallel and communicating with each other. The second conductive strips 18 of the first internal disk 15 are orthogonal to and in contact with the second conductive strips 18 of the second internal disk 29. The fourth adhesive layer 05 in the gap between adjacent first conductive strips 17 of the first external disk 14 is bonded to the fifth adhesive layer 06 in the gap between adjacent first conductive strips 17 of the second external disk 28. The fourth adhesive layer 05 in the gap between adjacent second conductive strips 18 of the first internal disk 15 is bonded to the fifth adhesive layer 06 in the gap between adjacent second conductive strips 18 of the second internal disk 29.

[0062] The structure of the printed circuit board according to Embodiment 7 of the present utility model is as Figure 14 and Figure 15 shown. Different from Embodiment 6, the first external disk 14 and the first internal disk 15 each include a third conductive strip 19. The second external disk 28 and the second internal disk 29 at both ends of the jumper 27 are solid structures. The width of the third conductive strip 19 is smaller than the widths of the second external disk 28 and the second internal disk 29. The third conductive strip 19 of the first external disk 14 is arranged in the middle of the second external disk 28. The fourth adhesive layer 05 on both sides of the third conductive strip 19 of the first external disk 14 is bonded to the second external disk 28. The third conductive strip 19 of the first internal disk 15 is arranged in the middle of the second internal disk 29. The fourth adhesive layer 05 on both sides of the third conductive strip 19 of the first internal disk 15 is bonded to the second internal disk 29.

[0063] The structure of the printed circuit board according to Embodiment 8 of the present utility model is as Figure 14 and Figure 16 shown. Different from Embodiment 7, the first external disk 14 and the first internal disk 15 each include a third conductive strip 19. The second external disk 28 and the second internal disk 29 each include a plurality of fourth conductive strips 71 arranged in parallel and communicating with each other. The width of the third conductive strip 19 is smaller than the length of the fourth conductive strip 71. The third conductive strip 19 of the first external disk 14 is arranged in the middle of the second external disk 28. The third conductive strip 19 of the first external disk 14 is orthogonal to and in contact with the fourth conductive strip 71 of the second external disk 28. The third conductive strip 19 of the first internal disk 15 is arranged in the middle of the second external disk 28. The third conductive strip 19 of the first internal disk 15 is orthogonal to and in contact with the fourth conductive strip 71 of the second internal disk 29. The fourth adhesive layer 05 on both sides of the third conductive strip 19 of the first external disk 14 is bonded to the fourth conductive strip 71 of the second external disk 28. The fourth adhesive layer 05 on both sides of the third conductive strip 19 of the first internal disk 15 is bonded to the fourth conductive strip 71 of the second internal disk 29.

Claims

1. A double-layer or multi-layer printed circuit board, comprising a first circuit layer and a second circuit layer, wherein the first circuit layer comprises a first circuit, the second circuit layer comprises a second circuit, and at least one first connection point is included between the first circuit and the second circuit, characterized in that: It includes a first intermediate layer arranged between a first circuit layer and a second circuit layer, the first intermediate layer includes a first insulating layer and a first bonding layer, the first insulating layer covers or bonds to the top surface of the first circuit, the first bonding layer covers the top surface of the first insulating layer, and the bottom surface of the second circuit layer is bonded to the top surface of the first insulating layer through the first bonding layer; the first intermediate layer includes an avoidance space of a first connection point or a first avoidance groove corresponding to the first connection point, and the avoidance space or the first avoidance groove includes a first connector electrically connecting the second circuit to the first circuit.

2. The printed circuit board according to claim 1, characterized in that: The second circuit includes a downwardly bent recessed body as the first connecting body at the first connecting point. The recessed body is located in the corresponding first avoiding groove. The bottom surface of the recessed body contacts the top surface of the first circuit to form an electrical connection.

3. The printed circuit board according to claim 2, characterized in that: The middle part of the recessed body comprises a through hole, the through hole is filled with a first conductor, the periphery of the first conductor is connected to the inner wall of the through hole, and the bottom surface of the first conductor is connected to the top surface of the first circuit.

4. The printed circuit board according to claim 3, characterized in that: The recessed body comprises a plurality of radial weakening grooves which are transparent from top to bottom, and the plurality of radial weakening grooves are arranged in a star shape with the through hole as the center.

5. The printed circuit board according to claim 1, characterized in that: A second conductor corresponding to the first connection point is included as the first connection body, the second conductor is arranged in the corresponding first avoidance groove, the bottom surface of the second conductor is connected to the top surface of the first circuit, and the top surface of the second conductor is connected to the bottom surface of the second circuit.

6. The printed circuit board according to claim 1, characterized in that: The device comprises a third circuit layer and a second intermediate layer, wherein the third circuit layer comprises a third circuit, and the third circuit and the second circuit comprise at least one second connection point, the second intermediate layer comprises a second insulating layer and a second bonding layer, the second insulating layer covers or is bonded to the top surface of the second circuit, the second bonding layer covers the top surface of the second insulating layer, and the bottom surface of the third circuit layer is bonded to the top surface of the second insulating layer through the second bonding layer; The second intermediate layer includes a second avoidance groove corresponding to the second connection point, and the second avoidance groove includes a second connector electrically connecting the third circuit and the second circuit.

7. The printed circuit board according to claim 1 or 6, characterized in that: It includes a solder resist layer, which includes at least one pad window; the second circuit layer or the third circuit layer is a top circuit layer, and the second circuit or the third circuit is a top circuit; the top circuit includes at least one pad, the solder resist layer covers the top circuit layer, and the pad is arranged in the pad window corresponding to the solder resist layer.

8. The printed circuit board according to claim 1, characterized in that: It comprises a substrate and a third adhesive layer, wherein the bottom surface of the first circuit layer is adhered to the substrate through the third adhesive layer.

9. The printed circuit board according to claim 1, characterized in that: The invention comprises a first substrate, a second substrate, a fourth adhesive layer and a fifth adhesive layer, wherein the fourth adhesive layer is attached to the top surface of the first substrate, and the fifth adhesive layer is attached to the bottom surface of the second substrate; the bottom surface of the first circuit layer is adhered to the top surface of the first substrate through the fourth adhesive layer, and the top surface of the second circuit layer is adhered to the bottom surface of the second substrate through the fifth adhesive layer; the first circuit comprises a planar coil, the planar coil comprises a planar winding, a first external connection plate and a first internal connection plate, the outer end of the planar winding is connected to the first external connection plate, and the inner end of the planar winding is connected to the first internal connection plate; The second circuit includes a jumper, a second external connection disk and a second internal connection disk, the outer end of the jumper is connected to the second external connection disk, and the inner end of the jumper is connected to the second internal connection disk; the first external connection disk and the second external connection disk are bonded to form the first first connection point, and the first internal connection disk and the second internal connection disk are bonded to form the second first connection point; the first insulating layer includes an insulating bridge, and the first adhesive layer includes an adhesive bridge, which is arranged between the first external connection disk and the first internal connection disk and spans the planar winding; the bottom surface of the jumper is bonded to the top surface of the insulating bridge through the adhesive bridge; The first substrate and the second substrate are pressed and bonded together through a fourth adhesive layer and a fifth adhesive layer; the first substrate and the second substrate are paper substrates, plastic substrates, resin substrates or metal substrates.

10. The printed circuit board according to claim 9, characterized in that: The first external pad and the second external pad each include a plurality of first conductive strips arranged in parallel and interconnected, the first conductive strips of the first external pad being orthogonal to the first conductive strips of the second external pad; the first internal pad and the second internal pad each include a plurality of second conductive strips arranged in parallel and interconnected, the second conductive strips of the first internal pad being orthogonal to the second conductive strips of the second internal pad; the fourth adhesive layer in the gap between the adjacent first conductive strips of the first external pad is bonded to the fifth adhesive layer in the gap between the adjacent first conductive strips of the second external pad; The fourth adhesive layer in the gap between the second conductive strips adjacent to the first inner land is bonded to the fifth adhesive layer in the gap between the second conductive strips adjacent to the second inner land.

11. The printed circuit board according to claim 9, characterized in that: The first external disk and the first internal disk each include a third conductive strip, and the width of the third conductive strip is smaller than the width of the second external disk and the second internal disk; the third conductive strip of the first external disk is arranged in the middle of the second external disk, and the fourth adhesive layers on both sides of the third conductive strip of the first external disk are bonded to the second external disk; the third conductive strip of the first internal disk is arranged in the middle of the second internal disk, and the fourth adhesive layers on both sides of the third conductive strip of the first internal disk are bonded to the second internal disk.

12. The printed circuit board according to claim 9, characterized in that: The first external disk and the first internal disk each include a third conductive strip, and the second external disk and the second internal disk each include a plurality of fourth conductive strips arranged in parallel and interconnected; the width of the third conductive strip is smaller than the length of the fourth conductive strip, the third conductive strip of the first external disk is arranged in the middle of the second external disk, the third conductive strip of the first external disk is orthogonal to the fourth conductive strip of the second external disk, the third conductive strip of the first internal disk is arranged in the middle of the second external disk, and the third conductive strip of the first internal disk is orthogonal to the fourth conductive strip of the second internal disk; the fourth adhesive layer on both sides of the third conductive strip of the first external disk is bonded to the fourth conductive strip of the second external disk; the fourth adhesive layer on both sides of the third conductive strip of the first internal disk is bonded to the fourth conductive strip of the second internal disk.

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