CN117835557A

CN117835557A - Magnetic circuit board and manufacturing method thereof

Info

Publication number: CN117835557A
Application number: CN202311696745.1A
Authority: CN
Inventors: 朱运乐; 胡军荣; 林以炳; 程骄
Original assignee: Jingwang Electronic Technology Zhuhai Co ltd
Current assignee: Jingwang Electronic Technology Zhuhai Co ltd
Priority date: 2023-12-11
Filing date: 2023-12-11
Publication date: 2024-04-05

Abstract

The application is applicable to the technical field of circuit boards and provides a manufacturing method of a buried magnetic circuit board, which comprises the following steps: providing a substrate, wherein a magnetic sheet is embedded in the substrate; drilling a first through hole on the substrate, wherein the first through hole is positioned in a nonfunctional area of the magnetic sheet; plugging resin into the first through hole and curing the resin; copper deposition and electroplating treatment are carried out on the substrate so as to form electroplated copper layers on two sides of the substrate respectively; the electroplated copper layer is subjected to patterning treatment to manufacture an outer layer pattern circuit and a copper cap covering the first through hole. The application also provides a buried magnetic circuit board. The manufacturing method of the buried magnetic circuit board and the buried magnetic circuit board solve the problems that the bonding force between the magnetic sheet and the substrate is insufficient and the buried magnetic circuit board is easy to delaminate.

Description

Magnetic circuit board and manufacturing method thereof

Technical Field

The invention relates to the technical field of circuit boards, in particular to a buried magnetic circuit board and a manufacturing method thereof.

Background

The buried magnetic circuit board is a circuit board embedded with magnetic sheets. The embedded magnetic circuit board replaces a surface-mounted inductance element, so that the assembly volume of the circuit board can be reduced, the integration level of an electronic product is improved, and the electronic product is beneficial to the development of miniaturization and flattening.

At present, the magnetic embedding plate has been developed to be directly packaged with an IC wafer, and when the magnetic embedding plate is manufactured, large-size magnetic sheets are embedded into a circuit board, and a plurality of magnetic devices are arranged on one magnetic sheet. When packaging, each magnetic device needs to be cut from a circuit board embedded with a magnetic sheet, the bonding force between the magnetic sheet and a substrate is poor due to the influence of cutting force in the vertical direction during cutting, and the magnetic sheet and the substrate are layered during reliability test.

Disclosure of Invention

In view of this, the present application provides a buried magnetic circuit board and a method for manufacturing the same, so as to solve the problem that the bonding force between the magnetic sheet and the substrate is insufficient and the buried magnetic circuit board is easy to delaminate.

The first aspect of the present application provides a method for manufacturing a buried magnetic circuit board, including:

providing a substrate, wherein a magnetic sheet is embedded in the substrate;

drilling a first through hole in the substrate, wherein the first through hole is positioned in a nonfunctional area of the magnetic sheet;

plugging resin into the first through hole and curing the resin;

copper deposition and electroplating treatment are carried out on the substrate so as to form electroplated copper layers on two sides of the substrate respectively;

and patterning the electroplated copper layer to manufacture an outer layer pattern circuit and a copper cap covering the first through hole.

In the method for manufacturing the buried magnetic circuit board provided by the embodiment of the application, after the substrate is manufactured, the first through hole is drilled in the substrate, the first through hole is located in the nonfunctional area of the magnetic sheet, then the resin is plugged into the first through hole and cured, and then copper deposition, electroplating and patterning processing are continued to manufacture the buried magnetic circuit board. Because be equipped with first through-hole and first through-hole intussuseption and have resin in the magnetic sheet, after the resin solidification, the resin has played the bonding effect, can bond magnetic sheet and base plate fixed, has promoted the cohesion between magnetic sheet and the base plate, avoids appearing magnetic sheet and the problem of base plate layering when follow-up reliability test or cutting.

In some embodiments, the method of making further comprises:

drilling a through hole on the substrate;

and carrying out copper deposition and electroplating treatment on the substrate so as to metalize the via hole.

In some embodiments, the via is drilled by a first drilling step;

after metallizing the via hole, the first via hole is drilled by a second drilling step.

In some embodiments, the first drilling step comprises:

windowing two sides of the substrate at the preset position of the through hole in a laser drilling mode to expose the magnetic sheet;

and drilling through the magnetic sheet in a mechanical drilling mode to form a through hole penetrating through the substrate.

In some embodiments, the second drilling step comprises:

windowing two sides of the substrate at the preset position of the first through hole in a laser drilling mode to expose the magnetic sheet;

and drilling through the magnetic sheet by a mechanical drilling mode so as to form a first through hole penetrating through the substrate.

In some embodiments, the method of making further comprises:

after curing the resin, leveling the resin protruding out of the first through hole;

and after the first through hole is drilled on the substrate, deburring and cleaning the substrate.

In some embodiments, a substrate is provided, comprising:

providing a first sub-board, a second sub-board and a third sub-board, wherein an accommodating hole is formed in the second sub-board;

the magnetic sheet is accommodated in the accommodating hole, and two sides of the second daughter board are respectively pressed and bonded with the first daughter board and the second daughter board through prepregs;

and the resin in the first through hole is adhered to the prepreg.

In some embodiments, the copper cap has a thickness of greater than or equal to 8 microns.

In some embodiments, the magnetic sheet is provided with a magnetic device, and four corners of the magnetic device are respectively provided with at least one first through hole.

An embodiment of the second aspect of the present application proposes a buried magnetic circuit board manufactured by the manufacturing method of the buried magnetic circuit board according to the first aspect.

The buried magnetic circuit board provided by the embodiment of the application promotes the binding force between the magnetic sheet and the substrate, and avoids the problem of layering of the magnetic sheet and the substrate during subsequent reliability test or cutting.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flowchart of a method for manufacturing a buried magnetic circuit board according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a substrate according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of the structure of the substrate shown in FIG. 2 after drilling a first through hole;

fig. 4 is a schematic structural diagram of a substrate after lamination according to an embodiment of the present disclosure;

FIG. 5 is a schematic view of the structure of the substrate shown in FIG. 4 after drilling a first via;

FIG. 6 is a schematic view of the structure of the substrate shown in FIG. 5 after plugging the holes with resin;

FIG. 7 is a schematic view of the structure of the substrate shown in FIG. 6 after the fabrication of an electroplated copper layer and the fabrication of an outer pattern line;

fig. 8 is a flowchart of a method for manufacturing a buried magnetic circuit board according to another embodiment of the present application.

The meaning of the labels in the figures is:

100. a buried magnetic circuit board;

10. a substrate; 11. a first sub-board; 12. a second sub-board; 121. a receiving hole; 13. a third sub-board; 14. a prepreg;

20. a magnetic sheet; 21. a magnetic device; 101. a first through hole;

30. a resin;

40. electroplating a copper layer; 41. a copper cap.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below with reference to the accompanying drawings, i.e. embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "a plurality of" is two or more, unless specifically defined otherwise.

It should be further noted that, in the embodiments of the present application, the same reference numerals denote the same components or the same parts, and for the same parts in the embodiments of the present application, reference numerals may be given to only one of the parts or the parts in the drawings by way of example, and it should be understood that, for other same parts or parts, the reference numerals are equally applicable.

For the purpose of illustrating the technical aspects of the present application, reference is made to the following description taken in conjunction with the accompanying drawings and examples.

The first aspect of the present application proposes a method for manufacturing a buried magnetic circuit board, which is used for manufacturing a buried magnetic circuit board. Referring to fig. 1 to 7, the method for manufacturing the buried magnetic circuit board includes:

step S110: a base plate 10 is provided, and a magnetic sheet 20 is embedded in the base plate 10.

Referring to fig. 2 and 4, the substrate 10 is formed by laminating a plurality of sub-boards, the substrate 10 includes one or more metal layers, and the magnetic sheet 20 is embedded in the substrate 10. Alternatively, both sides of the magnetic sheet 20 are respectively attached to one layer of prepreg 14.

The number of the sub-boards and the structure of the sub-boards in the substrate 10 can be set according to practical requirements, which is not limited in this application.

The prepreg, also called "PP sheet", is one of the main materials in the production of the multilayer board, mainly comprises resin 30 and reinforcing materials, the reinforcing materials are also divided into glass fiber cloth, paper base, composite materials and the like, and most of prepregs (adhesive sheets) used for manufacturing the multilayer printed board adopt glass fiber cloth as the reinforcing materials.

Step S120: a first through hole 101 is drilled in the substrate 10, the first through hole 101 being located in a nonfunctional area of the magnetic sheet 20.

The first through holes 101 penetrate through the substrate 10, and the first through holes 101 are located in the nonfunctional area of the magnetic sheet 20, and the number of the first through holes 101 may be one or more. The method of drilling the first through hole 101 may be laser drilling, mechanical drilling, a combination of laser and mechanical drilling, or the like. The aperture of the first through hole 101 may be set according to the size of the nonfunctional area.

Referring to fig. 2 to 5, the magnetic sheet 20 has a functional region and a non-functional region, wherein the functional region of the magnetic sheet 20 refers to a region for generating a function, for example, the functional region may be a pattern region, a hole region, a solder mask white mark region, etc., and the non-functional region of the magnetic sheet 20 is a region that does not affect the function of the product.

In some embodiments, the magnetic sheet 20 is provided with a plurality of magnetic devices 21, for example, the magnetic sheet 20 has a width of 8.5mm, a length of 19.0mm, and a thickness of 0.15mm, one magnetic sheet 20 corresponds to 10 magnetic devices 21, and the magnetic devices 21 have a length of 4.0mm and a width of 3.5mm. The size of the magnet sheet 20, the number of the magnetic devices 21, and the size are not limited in this application.

Each magnetic device 21 has a functional region and a nonfunctional region, the nonfunctional regions are located at the four corners of the magnetic device 21, and then in step S120, a first through hole 101 is drilled in each magnetic device 21, and the first through hole 101 is located at the nonfunctional region of the magnetic device 21.

The dashed line in fig. 3 illustrates a cut line. After the buried magnetic circuit board 100 is manufactured, the buried magnetic circuit board 100 is cut along a plurality of dicing lines, and the plurality of magnetic devices 21 can be separated.

Step S130: the resin 30 is plugged into the first through-hole 101 and the resin 30 is cured.

As shown in fig. 6, the resin 30 is first inserted into the first through hole 101, the first through hole 101 is filled with the resin 30, and then the substrate 10 is baked to cure the resin 30. In this way, the resin 30 can be adhered to the adjacent prepreg 14, and the magnetic sheet 20 and the prepreg 14 are riveted and fixed by the resin 30, so that the bonding force between the magnetic sheet 20 and the substrate 10 is improved.

In some embodiments, since the prepreg 14 is generally composed of fiberglass cloth and resin, in order to strengthen the bonding force between the magnetic sheet 20 and the prepreg 14, a resin ink is used for plugging holes. Optionally, the hole is plugged by adopting a vacuum resin hole plugging mode, the scraper speed can be 100-200 mm/s, the scraper pressure can be 0.2-1.0 MPa, the ink covering knife speed is 200-300 mm/s, and the ink covering knife pressure is 0.1-0.3 MPa. For example, the doctor blade speed may be 150mm/s, the doctor blade pressure may be 0.5MPa, the ink-jet blade speed 250mm/s, and the ink-jet blade pressure 0.2MPa.

Step S140: the substrate 10 is subjected to copper deposition and plating treatment to form copper plating layers 40 on both sides of the substrate 10, respectively.

As shown in fig. 7, the substrate 10 is first copper-plated so that copper can be plated on the resin 30 in the subsequent plating; then, the substrate 10 is electroplated by means of vertical electroplating, and electroplated copper layers 40 are formed on both sides of the substrate 10, respectively.

Step S150: the electroplated copper layer 40 is subjected to a patterning process to make an outer pattern line and a copper cap 41 covering the first via 101.

With continued reference to fig. 7, copper caps 41 are disposed at two ends of each first through hole 101, and one copper cap 41 may cover one first through hole 101 or may cover a plurality of first through holes 101; and the outer layer pattern circuit is manufactured according to the design.

In the method for manufacturing the buried magnetic circuit board 100 provided in the embodiment of the present application, after the substrate 10 is manufactured, the first through hole 101 is drilled in the substrate 10, the first through hole 101 is located in the nonfunctional area of the magnetic sheet 20, then the resin 30 is plugged into the first through hole 101 and cured, and then the copper deposition, electroplating and patterning processes are continued to manufacture the buried magnetic circuit board 100. Because the magnetic sheet 20 is provided with the first through hole 101, and the resin 30 is filled in the first through hole 101, after the resin 30 is solidified, the resin 30 plays a role in bonding, so that the magnetic sheet 20 and the substrate 10 can be bonded and fixed, the bonding force between the magnetic sheet 20 and the substrate 10 is improved, and the problem that the magnetic sheet 20 and the substrate 10 are layered during subsequent reliability test or cutting is avoided.

Referring to fig. 1 to 8, in some embodiments, after providing the substrate 10 after lamination, the manufacturing method further includes:

in step S111, a via hole is drilled in the substrate 10.

The substrate 10 is provided with a plurality of metal layers, and the via holes are used for conducting lines of different layers. The via hole may be drilled by mechanical drilling, laser drilling, a combination of laser and mechanical drilling, or the like.

In step S112, copper deposition and electroplating are performed on the substrate 10 to metallize the via holes.

By performing copper deposition and electroplating treatment on the substrate 10, a copper layer can be formed on the wall of the via hole, so that the via hole is formed as a metallized hole, and the via hole can conduct the metal layers on both sides thereof.

By adopting the above technical scheme, the substrate 10 can be used for conducting lines of different layers by using the metallized via holes.

In some embodiments, the via is drilled by a first drilling step; after metallizing the via holes, the first via holes 101 are drilled by a second drilling step.

Specifically, a via hole is drilled through a first drilling step, then the via hole is metallized through first copper deposition and electroplating, and a first via hole 101 is not drilled at this time; next, the first through hole 101 is drilled by the second drilling step.

By adopting the technical scheme, the manufacturing method comprises the steps of drilling the through holes and realizing metallization of the through holes, drilling the first through holes 101, and eliminating copper plating in the first through holes 101, so that the resin 30 in the first through holes 101 can be directly adhered to the prepreg 14, and the bonding force between the resin 30 and the substrate 10 is good.

It will be appreciated that in other embodiments, the via and the first via 101 may also be drilled simultaneously.

In some embodiments, the first drilling step comprises: windowing is carried out on two sides of the substrate 10 at the preset position of the through hole in a laser drilling mode, and the magnetic sheet 20 is exposed; the magnetic sheet 20 is drilled through by means of mechanical drilling to form a via hole penetrating the substrate 10.

The traditional drilling mode is to use mechanical drilling or laser drilling, because the magnetic sheet 20 is a rigid material, the mechanical drilling is directly used, the drilling is continued after the magnetic sheet 20 is drilled, the magnetic sheet 20 is easy to drive to cause deflection, the laser drilling is directly adopted, the laser energy needs to be adjusted to be maximum and is not easy to burn through, and the cost is too high, so the drilling is carried out in the modes of laser windowing and mechanical drilling of the magnetic sheet 20, the two sides of the substrate 10 are windowed by laser firstly, the magnetic sheet 20 is burned, and then the magnetic sheet 20 is penetrated through the mechanical drilling hole, so that a via hole can be formed.

In the manufacturing method provided by the embodiment, the drilling mode of the through hole has lower cost, the magnetic sheet 20 is not easy to deviate, and the yield of products is improved.

In some embodiments, the second drilling step comprises: windowing is carried out on two sides of the substrate 10 at the preset position of the first through hole 101 by a laser drilling mode, and the magnetic sheet 20 is exposed; the magnetic sheet 20 is drilled through by means of mechanical drilling to form a first through hole 101 penetrating the substrate 10.

Therefore, the drilling mode of the first through hole 101 also has lower cost, and the magnetic sheet 20 is not easy to deviate, so that the yield of the product is improved.

In some embodiments, the method of making further comprises: after the resin 30 is cured, the resin 30 protruding outside the first through hole 101 is subjected to leveling treatment.

Specifically, the resin 30 higher than the copper surface is ground and leveled through the grinding brush, so that the leveling of the double-sided resin 30 and the copper surface is ensured, and the subsequent copper plating is facilitated.

In some embodiments, the method of making further comprises: after the first through hole 101 is drilled on the substrate 10, deburring and cleaning are performed on the substrate 10, so that the surface of the substrate 10 is flat, and subsequent copper plating is facilitated.

Referring to fig. 4 and 7, in some embodiments, a substrate 10 is provided, including: providing a first sub-board 11, a second sub-board 12 and a third sub-board 13, wherein a containing hole 121 is formed in the second sub-board 12; the magnetic sheet 20 is accommodated in the accommodation hole 121, and both sides of the second sub-board 12 are bonded to the first sub-board 11 and the second sub-board 12 by pressing through the prepreg 14. Wherein the resin 30 in the first through hole 101 is adhered to the prepreg 14.

The first sub-board 11 and the third sub-board 13 may have a single-layer structure or a multi-layer structure, for example, the first sub-board 11 and the third sub-board 13 may be copper foil, a single-sided copper-clad core board, a double-sided copper-clad core board, and the like. In one embodiment, the second daughter board 12 includes an insulating dielectric layer 131 and copper layers 132 disposed on both sides of the insulating dielectric layer 131.

The second sub-board 12 may be a single-layer or multi-layer structure, for example, the second sub-board 12 is an insulating dielectric layer, and for another example, the second sub-board 12 includes a plurality of core boards and prepregs 14 disposed between the core boards. The second sub-board 12 is provided therein with a receiving hole 121 for the magnetic sheet 20.

Before lamination, the first sub-board 11, the prepreg 14, the second sub-board 12 containing the magnetic sheet 20, the prepreg 14 and the third sub-board 13 are sequentially laminated, and then two sides of the second sub-board 12 are respectively laminated and bonded with the first sub-board 11 and the second sub-board 12 through the prepreg 14 by hot pressing, so that the substrate 10 embedded with the magnetic sheet 20 is formed.

After the resin is plugged and cured in step S130, the resin 30 can be adhered to the adjacent prepreg 14, so that the bonding force between the magnetic sheet 20 and the substrate 10 is improved, and the problem of delamination between the magnetic sheet 20 and the adjacent structure is avoided.

In some embodiments, the thickness of the copper cap 41 is greater than or equal to 8 microns.

The thickness of the copper cap 41 may be 8 micrometers to 15 micrometers, but is not limited thereto. By satisfying the above condition, the copper cap 41 covering the resin 30 can function to further fix the resin 30, further reducing the probability of delamination of the wiring board.

In some embodiments, the magnetic sheet 20 is provided with a magnetic device 21, and four corners of the magnetic device 21 are respectively provided with at least one first through hole 101.

The magnetic sheet 20 is provided with one or more magnetic devices 21, and the magnetic devices 21 are rectangular. At least one first through hole 101 is respectively arranged at four corners of each magnetic device 21, so that the binding force between each magnetic device 21 and the substrate 10 can be effectively improved.

The arrangement of the first through holes 101 is not limited thereto, and for example, in other embodiments, one first through hole 101 may be provided in each magnetic device 21, or two first through holes 101 may be provided along the diagonal line of the magnetic device 21. Of course, the first through hole 101 may be provided only on a part of the magnetic device 21.

Some embodiments of the present application provide a method for manufacturing a buried magnetic circuit board 100, including: pressing, first drilling, first copper deposition electroplating, second drilling, resin hole plugging and baking, resin 30 grinding and second copper deposition electroplating.

Pressing: the laminated substrate 10 is ready.

First drilling: drilling a via hole in the substrate 10, wherein the via hole penetrates through the substrate 10;

plating copper by first copper deposition: plating a copper layer with preset thickness on the surface of the substrate 10 and in the through holes, wherein the first electroplating step is used for meeting the requirement of the thickness of the hole copper;

and (5) drilling the corner hole for the second time: drilling a first through hole 101 in the substrate 10 according to the data of the first through hole 101;

plugging holes of resin: because the prepreg 14 is generally composed of glass fiber cloth and resin 30, resin ink is selected for plugging holes, a vacuum resin plugging mode can be adopted for plugging holes, and whether the prepreg is full is checked after plugging holes;

resin 30 baking plate: the baking temperature is 150 ℃ and the baking time is 60min, so that the curing of the resin 30 is ensured;

resin 30 grinding: the resin 30 higher than the copper surface is ground and leveled by a grinding brush, so that the two-sided resin 30 and the copper surface are ensured to be leveled;

secondary copper deposition electroplating: the second electroplating mainly comprises copper plating of cap 41 and meeting the requirements of surface copper, plating of cap 41 at the position of the orifice of first through hole 101, covering resin 30, further fixing resin 30, and copper deposition for copper plating on resin 30, wherein the polishing of resin 30 can lead to reduction of surface copper, and the requirement of surface copper is met by adding plating, and the requirements of both are combined to determine the parameters of the second electroplating.

An embodiment of the second aspect of the present application proposes a buried magnetic circuit board 100 manufactured by the manufacturing method of the buried magnetic circuit board 100 as provided in the first aspect.

The buried circuit board 100 includes a substrate 10 and a magnetic sheet 20 embedded in the substrate 10, wherein a first through hole 101 is formed in the substrate 10, and a resin 30 is filled in the first through hole 101, and the resin 30 can promote a bonding force between the magnetic sheet 20 and the substrate 10.

The buried magnetic circuit board 100 solves the problem that the bonding force between the magnetic sheet 20 and the substrate 10 is insufficient and the buried magnetic circuit board 100 is easily layered.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. The manufacturing method of the buried magnetic circuit board is characterized by comprising the following steps:

providing a substrate, wherein a magnetic sheet is embedded in the substrate;

plugging resin into the first through hole and curing the resin;

2. The method for manufacturing a buried magnetic circuit board according to claim 1, further comprising:

drilling a through hole on the substrate;

3. The method for manufacturing a buried magnetic circuit board according to claim 2, characterized in that,

drilling the via hole through a first drilling step;

4. The method of manufacturing a buried magnetic circuit board according to claim 3, wherein said first drilling step includes:

5. The method of manufacturing a buried magnetic circuit board according to claim 3, wherein said second drilling step includes:

6. The method for manufacturing a buried magnetic circuit board according to claim 1, further comprising:

after curing the resin, leveling the resin protruding out of the first through hole; and/or the number of the groups of groups,

7. The method of manufacturing a buried magnetic wiring board according to any one of claims 1 to 6, wherein providing a substrate includes:

and the resin in the first through hole is adhered to the prepreg.

8. The method of manufacturing a buried magnetic circuit board according to any one of claims 1 to 6, wherein a thickness of the copper cap is 8 μm or more.

9. The method of manufacturing a buried magnetic wiring board according to any one of claims 1 to 6, wherein a magnetic device is provided on the magnetic sheet, and four corners of the magnetic device are respectively provided with at least one of the first through holes.

10. A buried magnetic circuit board, characterized in that it is manufactured by the manufacturing method of the buried magnetic circuit board according to any one of claims 1 to 9.