Method for manufacturing circuit board with laminated inductance circuit

Abstract

The invention discloses a method for manufacturing a circuit board with a laminated inductance circuit, which comprises the following steps of: taking a double-sided copper-clad plate, manufacturing a first inner-layer inductance circuit comprising an annular circuit with an opening on a copper layer on one side, pressing a single-sided copper-clad plate on one side of the first inner-layer inductance circuit, manufacturing a first blind hole, and conducting the copper layer on the other side and the first inner-layer inductance circuit, the method comprises the following steps of: forming interlayer circuit connection, continuously manufacturing a surface circuit pattern, laminating a single-sided copper-clad plate, manufacturing a blind hole, manufacturing a surface circuit pattern, and sequentially manufacturing and forming a circuit board with a laminated inductance circuit; the inductor circuit with the opening is manufactured for the circuit pattern of each layer, and the head end and the tail end of the annular circuit of each layer are interconnected in a cross-layer manner by using the blind hole, so that an integral cross-layer inductor structure is formed, the size of the circuit board during application is reduced, the high-density and high-integration performance of the circuit board is improved, the processing difficulty of the inductor is reduced, and the production cost is reduced. And the applicable performance and reliability of the inductor are improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit board processing, and particularly to a method for manufacturing a circuit board with a stacked inductor circuit. Background Art

[0002] With the development of intelligent electronic products, it is required that electronic modules have more and stronger functions. Therefore, the requirements for high density and high precision of circuit boards are also getting higher and higher.

[0003] When an inductor function needs to be provided on a circuit board, currently, an independent inductor component is generally used and fabricated on the surface of the circuit board by welding to provide the inductor function.

[0004] However, since the size of the inductor is generally large, this manufacturing method will reduce the functional density of the circuit board per unit area, which is not conducive to the high-density and high-integration applications of the circuit board. On the other hand, the method of welding the inductor requires independent manufacturing of the circuit board, independent manufacturing of the inductor, and independent welding. The matching requirements for the processing process are high, and the process is relatively complex. It is gradually difficult to meet the processing and application requirements of high-precision inductors, and the reliability of the inductor formed by welding is relatively low, and the service life is limited.

[0005] Currently, the inductors generally designed and fabricated on the circuit board body are planar inductors, that is, the inductor circuits are distributed on the same circuit pattern layer to form a concentric circular circuit structure. Application scenarios include wireless charging, non-contact induction modules, etc. However, the inductors with planar circuit patterns occupy a large area of the circuit board, and the application scenarios are relatively single, and it is difficult to form the application effects of function adjustment or function support.

[0006] Based on the above background and problems, a method for manufacturing a circuit board is provided, in which the inductor is designed and fabricated on the circuit board body, and an inductor circuit in the vertical stacking direction is formed. Summary of the Invention

[0007] Aiming at the problems existing in the prior art that the manufacturing method of welding an independent inductor component to the circuit board has a low functional density during application, a complex manufacturing process, and low reliability, and that the design and manufacture of a planar inductor on the circuit board body has a large area occupied on the circuit board and relatively single application scenarios, the present invention provides a method for manufacturing a circuit board with a stacked inductor circuit. S10: Take a double-sided copper clad laminate, which includes a first-side copper layer and a second-side copper layer, and fabricate a first circuit pattern including a first inner-layer inductor circuit on the first-side copper layer to form a core board; the first inner-layer inductor circuit is an annular circuit with an opening, one end of the opening is the first head end, and the other end is the first tail end.

[0008] S20: Press a single-sided copper clad laminate onto one side of the first inner-layer inductive circuit. The copper layer of the single-sided copper clad laminate is the third-side copper layer. Then, drill a first blind via between the second-side copper layer and the first inner-layer inductive circuit, and drill a second blind via between the third-side copper layer and the first inner-layer inductive circuit. After that, fabricate a second circuit pattern including a second inner-layer inductive circuit on the second-side copper layer. The second inner-layer inductive circuit is a ring-shaped circuit with an opening. One end of the opening is the second leading end, and the other end is the second trailing end. Fabricate a third circuit pattern including a third inner-layer inductive circuit on the third-side copper layer. The third inner-layer inductive circuit is a ring-shaped circuit with an opening. One end of the opening is the third leading end, and the other end is the third trailing end. The bottom end of the first blind via is connected to the first trailing end, and the top end is connected to the second leading end. The bottom end of the second blind via is connected to the first leading end, and the top end is connected to the third trailing end. The first stacked core board is fabricated integrally.

[0009] S30: Follow the steps of S20 to continue laminating on the upper and lower surfaces of the first stacked core board, and fabricate blind vias and circuit patterns containing inductive circuits until a multi-layer stacked board required by the design is formed. Then, fabricate a surface layer circuit pattern to form the circuit board with stacked inductive circuits.

[0010] Optionally, the entire upper and lower surfaces of the multi-layer stacked board are copper layers, which are the upper surface copper layer and the lower surface copper layer respectively. The manufacturing method further includes: S310: Drill through-holes inside the rings of the ring-shaped circuits of the multi-layer stacked board, and perform full-panel electroplating. Then, fabricate a surface circuit pattern on the entire board. The through-holes form via holes, and a circuit pattern board is formed integrally. The surface circuit pattern includes surface inductive circuits, and the surface inductive circuits are ring-shaped circuits with openings. S320: Fabricate magnetic cores inside the via holes to form the circuit board with stacked inductive circuits.

[0011] Optionally, the first circuit pattern, the second circuit pattern, and the third circuit pattern all include corresponding pad patterns. The pad patterns are distributed inside the rings of the ring-shaped circuits and are separated from the ring-shaped circuits.

[0012] Optionally, the size of the opening is from 20 μm to 1.0 mm.

[0013] Optionally, the first blind via, the second blind via, and the blind vias of each layer after the processing of step S30 are distributed in a staggered manner in a vertical cross-sectional shape according to the lamination distribution.

[0014] Optionally, the staggered distribution is in the same direction along the ring-shaped circuit.

[0015] Optionally, the misalignment distance is from 20 μm to 2.0 mm.

[0016] Optionally, the magnetic core is of a solid cylinder structure, and the manufacturing of the magnetic core is to weld the magnetic core into the via hole.

[0017] Optionally, the magnetic core is of a solid cylinder structure, and for manufacturing the magnetic core, a colloid is filled into the via hole to adhere the magnetic core into the via hole.

[0018] Optionally, the length of the magnetic core is less than or equal to 1.05 to 1.3 times the height of the via hole.

[0019] In the technical solution of the present invention, by designing and manufacturing an annular circuit with an opening for each layer of circuit pattern to form an inductive circuit, and using blind holes to interconnect the start ends and end ends of the annular circuits of each layer across layers to form an overall cross-layer single "coil" circuit, an inductive structure is integrally formed, so that the inductor is "embedded" in the circuit board body in a vertical stacked structure, effectively reducing the volume during the application of the circuit board, improving the high-density and high-integration performance of the circuit board, reducing the processing difficulty of the inductor, and improving the applicability and reliability of the inductor.

[0020] The manufacturing method first manufactures a core board, then gradually adds a stacked structure to both sides of the core board, and simultaneously manufactures blind holes when manufacturing the circuit pattern to form a circuit board with a stacked inductive circuit. Further, the blind holes of each layer are misaligned to increase the coherence of the single "coil" circuit and improve the surface flatness of the circuit board. Further, by manufacturing through holes and welding or bonding magnetic cores, a high-precision inductive effect is formed, further improving the application effect of the circuit board.

[0021] The overall design and processing form an effective front-back matching property, forming a processing effect with easy adjustment and easy processing, improving the high-density and reliability of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention 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 invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0023] Figure 1 It is the main process flow chart included in the embodiment of the present invention; Figure 2 It is the schematic plan view of the core board of the embodiment of the present invention; Figure 3 For Figure 2Schematic cross-sectional structure diagram expanded from A-A’; Figure 4 Schematic plan view of the first laminated core board according to an embodiment of the present invention; Figure 5 is Figure 4 Schematic cross-sectional structure diagram expanded from B-B’; Figure 6 Schematic plan view of a circuit board with a laminated inductor circuit according to an embodiment of the present invention; Figure 7 is Figure 6 Schematic cross-sectional structure diagram expanded from C-C’; Figure 8 Schematic plan view of a graphic board according to an embodiment of the present invention; Figure 9 Schematic plan view of another circuit board with a laminated inductor circuit according to an embodiment of the present invention; Figure 10 is Figure 9 Schematic cross-sectional structure diagram of D-D’ of

[0024] Explanation of reference numerals in the drawings:

[0025] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with embodiments with reference to the accompanying drawings. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, inside, outside, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0028] In addition, the descriptions such as "first" and "second" in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0029] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] Please refer to Figure 1 ; Figure 1 which is the main process flow chart included in the embodiment of the present invention.

[0031] A method for manufacturing a circuit board with a stacked inductance circuit according to an embodiment of the present invention includes Figure 1 the main manufacturing process flow, which will be described in detail in the following steps.

[0032] Please refer to Figure 2 and Figure 3 ; Figure 2 which is a schematic plan view of the core board according to an embodiment of the present invention, Figure 3 which is a schematic structural view of the A-A cross-section expansion of the core board according to an embodiment of the present invention.

[0033] Step S10: Take a double-sided copper clad laminate, the insulating dielectric layer 100 in the middle layer of which is made of FR-4, polyimide, PTFE or ceramic powder composite epoxy resin. The double-sided copper clad laminate includes a first-side copper layer and a second-side copper layer 120A. Make a first circuit pattern including a first inner-layer inductance circuit 110 on the first-side copper layer to form a core board 10.

[0034] The first inner-layer inductance circuit 110 is an annular circuit with an opening. One end of the opening is the first head end 1110, and the other end is the first tail end 1120.

[0035] Figure 3 The schematic structural view of the A-A cross-section expansion of Figure 2 adopts a ring-shaped cross-section structure schematic, that is, with the circuit center of the annular circuit of the first inner-layer inductance circuit 110 as the annular path, and in the direction of the cross-section trend JD, perform a cross-section to form a cross-section structure with the starting point and the ending point of the cross-section being the same point (cross-section start / end ST / EN), and expand from the cross-section start / end ST / EN point in two directions of A and A' to form a cross-section structure diagram; the cross-section principle methods of the following cross-section structure diagrams are the same.

[0036] In the embodiment of the present invention, an inductance line of each layer is formed by manufacturing an annular line with an opening, so as to form an inductance "coil" line in the vertical direction of the stacked layers. Since the annular lines of each layer need to form an annular body, but if it is in a closed-loop state, it is difficult to form an integral line structure continuous between layers. Therefore, an opening is provided to disconnect the annular line, and then it is interconnected with the adjacent layer line through a blind via to form a single cross-layer line structure.

[0037] Step S20: Press a single-sided copper clad laminate on one side of the first inner-layer inductance line 110, and the copper layer of the single-sided copper clad laminate is the third-sided copper layer; manufacture a first blind via 210 between the second-sided copper layer 120A and the first inner-layer inductance line 110; manufacture a second blind via 220 between the third-sided copper layer and the first inner-layer inductance line 110; then manufacture a second circuit pattern including the second inner-layer inductance line 120 on the second-sided copper layer 120A. The second inner-layer inductance line 120 is an annular line with an opening, one end of the opening is the second leading end 1210, and the other end is the second trailing end 1220. Manufacture a third circuit pattern including the third inner-layer inductance line 130 on the third-sided copper layer. The third inner-layer inductance line 130 is an annular line with an opening, one end of the opening is the third leading end 1310, and the other end is the third trailing end 1320. The bottom end of the first blind via 210 is connected to the first trailing end 1120, and the top end is connected to the second leading end 1210; the bottom end of the second blind via 220 is connected to the first leading end 1110, and the top end is connected to the third trailing end 1320; the overall manufacture forms the first stacked core board 20.

[0038] In this process of this embodiment, the overall manufacturing method is to use blind vias to form a cross-layer integral single line structure in the form of interconnecting the leading and trailing ends of the annular lines with openings in adjacent layers, realizing the open-loop annular shape of the single-layer line and the "coil" line effect of mutual connection between cross-layers.

[0039] In this embodiment, a multi-layer circuit board structure with interlayer blind vias is manufactured by the method of gradually adding layers to both sides of the core board 10. It should be noted that since the inductance is manufactured in the circuit board body in this embodiment and in the vertical direction, and the circuit patterns of each layer also include other lines besides the inductance lines, therefore, when manufacturing the circuit patterns of each layer, it is necessary to adopt the method of "pressing a single-sided copper clad laminate → etching the blind via pattern on the copper layer → laser drilling → blind via electroplating → manufacturing the surface circuit pattern" to form the complete manufacture of the blind vias and the surface circuit pattern.

[0040] In this embodiment, the size of the opening is 20 μm to 1.0 mm.

[0041] Since it is necessary to ensure that the inductance line of the copper layer is annular as much as possible, the size of the opening can be selected to be as small as possible according to the copper thickness to ensure the integrity of the "coil".

[0042] Step S30: According to step S20, the first laminated core board 20 is laminated on both sides, and blind holes and circuit patterns containing inductor circuits are made until the multi-layer laminated board required by the design is formed, and then the surface layer circuit pattern is made to form a circuit board 30 with a laminated inductor circuit.

[0043] In the same manner, the circuit structure and circuit pattern of each layer are manufactured layer by layer from the upper and lower surfaces of the first laminated core board 20 to form a circuit board 30 with a laminated inductor circuit.

[0044] It can be seen that the production method of adding layers layer by layer and using blind holes to connect the inductor lines of adjacent circuit layers to form a "coil" line with a vertical structure of a single line as a whole, creating the effect of "burying" the inductor into the circuit board body.

[0045] In this embodiment, the surface layer circuit pattern is divided into an upper surface layer circuit pattern and a lower surface layer circuit pattern, wherein the upper surface layer circuit pattern includes an upper surface inductor circuit 310, one end of the upper surface inductor circuit 310 connected to the blind hole is the upper surface head end 3110, and the other end is the upper surface tail end 3120, and the lower surface layer circuit pattern includes a lower surface inductor circuit 320, one end of the lower surface inductor circuit 320 connected to the blind hole is the lower surface tail end 3220, and the other end is the lower surface head end 3210.

[0046] It is worth noting that the upper surface tail end 3120 and the lower surface head end 3210 are not connected to the blind hole, that is, they are the tail end and head end of a single "coil" circuit, which can be connected to other circuits to form an inductive connectivity application.

[0047] Optionally, the first circuit pattern, the second circuit pattern and the third circuit pattern all include corresponding pad patterns 100A, and the pad patterns are distributed in the ring of the annular circuit and separated from the annular circuit.

[0048] In the present embodiment, a pad graphic 100A is provided. When a through hole 410 is not made subsequently, the pad graphic 100A plays a role as a core of an inductor to a certain extent. If a through hole 410 is made subsequently, a copper layer foundation for increasing the adhesion of electroplating on each layer can be provided, thereby forming a conductive hole with a more solid electroplating effect and higher reliability.

[0049] Optionally, the entire upper and lower surfaces of the multilayer laminate are copper layers, namely, an upper surface copper layer and a lower surface copper layer; and the manufacturing method further comprises: Step S310: A via hole 410 is drilled into the inside of the loop of the annular circuit of the multi-layer laminate to form a via board 30A, and the whole board is electroplated. The inner wall of the via hole 410 is electroplated separately to form an electroplated copper layer 430. Then, the surface circuit pattern is fabricated on the whole board, and the via hole forms a via, and a circuit pattern board 30A is formed as a whole. The surface circuit pattern includes a surface inductance circuit, and the surface inductance circuit is an annular circuit with an opening.

[0050] Optionally, the thickness of the electroplated copper layer 430 is 10 μm to 35 μm.

[0051] Step S320: A magnetic core 510 is fabricated inside the via to form another circuit board 30B with a stacked inductance circuit.

[0052] In this embodiment, the upper and lower surfaces of the fabricated multi-layer laminate are complete copper layers, that is, single-sided copper clad laminates on the upper and lower surfaces are laminated, blind holes on the upper and lower surfaces are fabricated, and after electroplating to fill the blind holes, the formed board body is drilled with via holes 410.

[0053] Optionally, when a pad pattern 100A is designed and fabricated, after drilling the via hole 410, a via hole ring 420 is still retained, that is, the unilateral dimension of the pad pattern 100A is larger than the dimension of the via hole 410, preferably larger by 25 μm to 100 μm.

[0054] Furthermore, to play roles such as concentrating magnetic flux, increasing the inductance value, or reducing self-inductance, a magnetic core can be fabricated into the annular circuit of the formed single "coil" circuit.

[0055] Optionally, the magnetic core 510 is a solid columnar structure. To fabricate the magnetic core 510, the magnetic core 510 is welded into the via hole, or a colloid is filled into the via hole to adhere the magnetic core 510 to the inside of the via hole.

[0056] Optionally, the filled colloid is acrylic glue, epoxy resin glue, or plugging resin.

[0057] Optionally, the colloid is filled by screen printing.

[0058] Optionally, the length of the magnetic core 510 is less than or equal to 1.05 times to 1.3 times the height of the via hole.

[0059] In this embodiment, a hole is drilled into the annular circuit, and the magnetic core is fixed to the circuit board by welding or bonding. The magnetic core can be a ceramic core, a ferrite core, a metal core, etc.

[0060] Optionally, the first blind hole 210, the second blind hole 220, and the blind holes of each layer after being processed in step S30 are distributed in a staggered manner in a vertical cross-sectional shape according to a stacked distribution.

[0061] Optionally, the staggered distribution is staggered in the same direction along the circular line.

[0062] Optionally, the distance of the stagger is from 20 μm to 2.0 mm.

[0063] In this embodiment, on the one hand, the staggered design is adopted, which can improve the distribution coherence of a single "coil" line. On the other hand, it disperses the distribution of blind vias in each layer to prevent problems such as local protrusions on the circuit board surface caused by blind via stacking or self-inductance, which affect the use effect of the circuit board; the stagger distance can be determined according to the copper thickness of the line, the spatial distribution and the required effect.

[0064] It should be noted that due to the high precision of the circuit board in the actual design and processing process, the actual structure diagram and the dimensions such as the thickness between each layer and the line width are at the micron level. For example, the thickness of each layer is generally between 5 μm and 50 μm. If the accompanying drawings of the specification are made according to the actual ratio, there will be a problem of unclear illustration. Therefore, in order to more clearly show the implementation process of the manufacturing method, the accompanying drawings of this embodiment are all schematic diagrams with the technical features enlarged, which do not represent the size of the actual structure diagram, nor an enlarged diagram of the actual structure diagram in proportion.

[0065] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A method for manufacturing a circuit board having a laminated inductor circuit, characterized in that: S10: taking a double-sided copper-clad laminate, which includes a first copper layer and a second copper layer, and forming a first circuit pattern including a first inner layer inductor circuit on the first copper layer to form a core board; The first inner layer inductor circuit is a ring circuit with an opening, one end of the opening is a first head end, and the other end of the opening is a first tail end; S20: Pressing a single-sided copper-clad laminate onto one side of the first inner-layer inductor circuit, wherein the copper layer of the single-sided copper-clad laminate is the third-side copper layer; and making a first blind hole between the second surface copper layer and the first inner layer inductor circuit; Making a second blind hole between the third-side copper layer and the first inner-layer inductor circuit; Then, a second circuit pattern including a second inner layer inductor circuit is formed on the second copper layer, wherein the second inner layer inductor circuit is a ring circuit with an opening, one end of the opening is a second head end, and the other end is a second tail end. A third circuit pattern including a third inner layer inductor circuit is made on the third copper layer, wherein the third inner layer inductor circuit is a ring circuit with an opening, one end of the opening is a third head end, and the other end is a third tail end. The bottom end of the first blind hole is connected to the first tail end, and the top end is connected to the second head end; the bottom end of the second blind hole is connected to the first head end, and the top end is connected to the third tail end; The first laminated core plate is formed by integrally manufacturing; S30: According to the step of S20, continue to laminate on the upper and lower surfaces of the first laminated core board, and make blind holes and circuit patterns containing inductor circuits until the multi-layer laminated board required by the design is formed, and then make surface layer circuit patterns to form the circuit board with laminated inductor circuits.

2. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 1, characterized in that: The upper and lower surfaces of the multi-layer laminate are all copper layers, namely, an upper surface copper layer and a lower surface copper layer; The production method further comprises: S310: drilling through holes in the ring of the annular circuit of the multi-layer laminated board, and electroplating the entire board, and then manufacturing a surface circuit pattern on the entire board, wherein the through holes form conductive holes, and the entire board is formed into a circuit pattern board; The surface circuit pattern includes a surface inductor circuit, and the surface inductor circuit is a ring circuit with an opening; S320: manufacturing a magnetic core in the conducting hole to form the circuit board with the laminated inductor circuit.

3. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 1 or 2, characterized in that: The first circuit pattern, the second circuit pattern and the third circuit pattern all include corresponding pad patterns, and the pad patterns are distributed in the ring of the annular circuit and separated from the annular circuit.

4. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 1 or 2, characterized in that: The size of the opening is 20 μm to 1.0 mm.

5. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 1 or 2, characterized in that: The first blind hole and the second blind hole, as well as the blind holes of each layer processed in step S30, are staggeredly distributed in a vertical cross-section in accordance with the stacking distribution.

6. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 5, characterized in that: The staggered distribution is staggered in the same direction along the annular line.

7. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 5, characterized in that: The misalignment distance is 20 μm to 2.0 mm.

8. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 2, characterized in that: The magnetic core is a solid column structure, and the manufacturing of the magnetic core is to weld the magnetic core into the conducting hole.

9. A method for manufacturing a circuit board having a laminated inductor circuit as claimed in claim 2, characterized in that: The magnetic core is a solid column structure, and the manufacturing of the magnetic core is to fill the conductive hole with colloid and adhere the magnetic core to the conductive hole.

10. A method for manufacturing a circuit board with a laminated inductor circuit as claimed in claim 2 or 7, characterized in that: The length of the magnetic core is less than or equal to 1.05 times to 1.3 times the height of the conducting hole.

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