Manufacturing process method of PCB (Printed Circuit Board) embedded with ultra-thin silicon steel sheet

Abstract

The invention discloses a manufacturing process method of a PCB (Printed Circuit Board) embedded with an ultrathin silicon steel sheet, which comprises the following steps: a lamination step: arranging a silicon steel sheet loaded with a magnetic chip between an inner layer with a winding circuit and an insulating layer of the PCB to form a stacked structure; a fusion step, wherein the stacked structure is preliminarily fused into a whole through heat of a fusion process; and a pressing step: carrying out whole-board pressing on the fused stacked structure to enable each layer of magnetic chip and the PCB to form an integrated structure. The problems that in the prior art, a machining mode for the internal stator of the axial flux motor is complex, and the machining precision requirement is high are solved.

Description

Technical Field

[0001] The invention relates to the field of PCB technology, and in particular to a manufacturing process method of a PCB board with embedded ultra-thin silicon steel sheets. Background Art

[0002] In the prior art, the internal stator of the axial flux motor is usually manufactured by PCB processing. Currently, a hole is drilled in the coil to bury the iron core inside (after the winding is printed on the PCB board, a complex machining process is still required to mill a through hole in the middle of the coil for inserting the stator core) to enhance the magnetic flux. However, since drilling involves fine machining, the entire process is complicated and has high requirements for precision (high requirements for the alignment and positioning accuracy of the drill), and complete alignment cannot be achieved.

[0003] In view of this, the present technical solution proposes a process method for directly burying the magnetic core into the inner layer of the PCB, that is, during the lamination process, the magnetic core is directly stacked and pressed, eliminating the process of drilling the coil and at the same time enhancing the magnetic flux, thereby integrating the magnetic flux design structure with the PCB inner layer coil design, enhancing the integrity of the product and simplifying the process flow. Summary of the invention

[0004] The technical solution of the present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main purpose of the present invention is to provide a PCB board manufacturing process method embedded with ultra-thin silicon steel sheets, aiming to solve the problem that the processing method for the internal stator of the axial flux motor in the prior art is complex and the processing accuracy requirement is high.

[0005] To achieve the above-mentioned purpose, the present invention provides a manufacturing process method for a PCB board with embedded ultra-thin silicon steel sheets, comprising a lamination step, in which a silicon steel sheet carrying a magnetic core sheet is arranged between an inner layer of the PCB with a winding circuit and an insulating layer to form a stacking structure; a hot melt area is solidified to prevent the stacking structure from loosening and causing alignment defects during placement in a press; and a pressing step, in which the fused stacking structure is pressed as a whole plate so that each layer of magnetic core sheet and the PCB form an integrated structure.

[0006] As a further solution of the present invention, before the lamination step, inner layer patterning and browning treatment are first performed.

[0007] In the production of multi-layer boards, when the inner layer is completed, the inner layer dry film is completed and the circuit is tested, browning is performed. This is mainly to increase the bonding strength between the inner copper layer and the PP (insulating layer). If the browning is not done well, it will lead to delamination of the PCB oxidation surface, incomplete etching of the inner layer, infiltration plating, delamination and explosion of the board.

[0008] As a further solution of the present invention, the thickness of the inner copper layer of the PCB is between 100-200 um.

[0009] As a further solution of the present invention, the thickness of the insulating layer is between 100-200 um.

[0010] As a further solution of the present invention, the thickness of the magnetic chip is the same as the thickness of the inner copper layer of the PCB.

[0011] As a further solution of the present invention, when performing the pressing step, the pressing curing temperature and time are 190° C.-195° C. and 80 min-100 min respectively.

[0012] As a further solution of the present invention, after the pressing step, forming processes including target drilling, hole drilling, copper deposition and electroplating are carried out in sequence.

[0013] The purpose of copper plating is to deposit a thin layer of copper on the entire printed circuit board (especially the hole wall) so that electroplating can be performed inside the hole to metallize the hole (there is copper in the hole for conduction) and achieve interlayer conduction.

[0014] As a further solution of the present invention, after the molding process, a resin hole filling process is performed to fill the via holes with epoxy resin to remove pits on the PCB surface.

[0015] As a further solution of the present invention, after the resin hole filling process step, the outer layer pattern is produced and tested.

[0016] The beneficial effects of the present invention are as follows: The present invention proposes a method for manufacturing a PCB board with embedded ultra-thin silicon steel sheets, in which (embedded) magnetic chips are arranged during the PCB stacking process. The embedded stacking and pressing method does not make a major change to the entire process, but simplifies the process steps, and is integrated with the PCB to further enhance the magnetic flux and improve the integrity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the technical solutions of the present invention or the technical solutions of the present invention in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the technical solutions of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the main process flow of the present invention.

[0019] Figure 2 It is a schematic diagram of a magnetic core formed in a winding coil after the magnetic core pieces in the present invention are pressed together.

[0020] Figure 3 It is a schematic diagram of the lamination and pressing process in the process flow of the present invention. DETAILED DESCRIPTION

[0021] as follows: Please see attached Figure 1-3 , The main implementation steps include a stacking step, in which a silicon steel sheet carrying magnetic chips is arranged between the inner layer of the PCB with the winding circuit and the insulating layer to form a stacking structure; a fusing step, in which the hot melt area is solidified to prevent the stacking structure from loosening and causing alignment defects during the process of being placed in the press; and a pressing step, in which the fused stacking structure is pressed as a whole board so that each layer of magnetic chips and the PCB form an integrated structure.

[0022] Main process principle: This solution mainly relies on the process of laminating the PCB through automatic matching equipment during the PCB production process. In this process, the silicon steel sheet carrying the magnetic chip is combined with the PCB to be pressed (between the inner layer of the PCB with the winding line and the insulating layer), and finally a stacking structure is formed. Then, through the hot melting and pressing process, each layer of the magnetic chip and the PCB form an integrated structure (where the hot melting is mainly to prevent the stacking structure from loosening during the transfer). This process flow not only simplifies the process steps (for example, it eliminates the step of milling a through hole in the middle of the coil for inserting the stator core), but also has the characteristics of easier matching of the magnetic flux and the winding, integrated molding, and better integrity. The entire process is simple and can be widely used in the field of axial flux motor manufacturing.

[0023] A preferred embodiment of the present invention is to firstly carry out inner layer pattern making and browning treatment before the lamination step. This is mainly to increase the bonding force between the inner layer copper and PP (insulating layer). If the browning is not good, it will lead to delamination of the PCB oxidation surface, incomplete etching of the inner layer, infiltration plating, delamination and explosion of the board and other problems.

[0024] A preferred embodiment of the present invention: the thickness of the inner copper layer of the PCB is between 100-200 um.

[0025] The preferred solution is that the inner copper thickness range and the insulation layer thickness are between 100-200um, and good press-fit matching can be achieved within this range.

[0026] A preferred embodiment of the present invention is that the thickness of the magnetic chip is the same as the inner copper thickness of the PCB.

[0027] A preferred embodiment of the present invention: during the lamination step, the lamination curing temperature and time are 190°C-195°C and 80min-100min respectively.

[0028] The pressing curing temperature and time interval are 190°C-195°C, 80min-100min. As a preferred solution, pressing in this range can obtain a more ideal integrated PCB overall structure.

[0029] A preferred embodiment of the present invention is as follows: after the pressing step, the forming process including target drilling, hole drilling, copper deposition and electroplating is carried out in sequence.

[0030] The purpose of copper plating is to deposit a thin layer of copper on the entire printed circuit board (especially the hole wall) so that electroplating can be performed inside the hole to metallize the hole (there is copper in the hole for conduction) and achieve interlayer conduction.

[0031] A preferred embodiment of the present invention is as follows: after the molding process, a resin hole filling process is performed to fill the via holes with epoxy resin to remove the pits on the PCB surface.

[0032] A preferred embodiment of the present invention is as follows: after the resin hole filling process step, the outer layer pattern is produced and tested.

[0033] The outer layer pattern production and testing process after the resin filling process is a process close to the final product, which is also a relatively conventional process in the current PCB processing technology (since this solution does not make too many changes to the existing process, it can be well integrated into the current process).

[0034] The above are only preferred embodiments of the technical solution of the present invention, and do not limit the patent scope of the technical solution of the present invention. All equivalent structural changes made by using the contents of the technical solution description and drawings of the present invention under the conception of the technical solution of the present invention, or directly / indirectly used in other related technical fields are included in the patent protection scope of the technical solution of the present invention.

Claims

1. A method for manufacturing a PCB board with embedded ultra-thin silicon steel sheet, characterized in that: The processing steps include: S1, lamination step, A silicon steel sheet carrying a magnetic chip is arranged between the inner layer of the PCB with the winding circuit and the insulating layer to form a stacked structure; S2, fusion step, Solidify the hot melt area to prevent the stacked structure from loosening and causing alignment defects during placement in the press; S3, pressing step, The fused stacked structure is pressed together as a whole board, so that each layer of magnetic chips and the PCB form an integrated structure.

2. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: Before the lamination step, inner layer pattern production and browning treatment are first performed.

3. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: The inner copper thickness of the PCB is between 100-200 um.

4. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: The thickness of the insulating layer is between 100-200 um.

5. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: The thickness of the magnetic chip is the same as the inner copper thickness of the PCB.

6. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: When performing the pressing step, the pressing curing temperature and time are 190° C.-195° C. and 80 min-100 min respectively.

7. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 1, characterized in that: After the pressing step, the forming steps including target drilling, hole drilling, copper deposition and electroplating are carried out in sequence.

8. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 7, characterized in that: After the molding process, the resin filling process is carried out to fill the vias with epoxy resin and remove the pits on the PCB surface.

9. The method for manufacturing a PCB board embedded with an ultra-thin silicon steel sheet according to claim 8, characterized in that: After the resin hole filling process step, the outer layer pattern is produced and tested.

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