Method for making circuits and substrates flush in PCB process

Abstract

The present invention discloses a method for making the circuit and substrate flush in the PCB process, including setting a filling layer, setting filling layers on both sides of the circuit board that has been completed through the circuit manufacturing process, the filling layers including a cushion layer, and a hard pressing plate, a separation layer and a mosaic layer stacked in sequence from the cushion layer to the surface of the circuit board; laminating the filling layers, laminating the filling layers on both sides toward the circuit board through a laminating device, so that the mosaic layer fills the gap of the circuit board, and then the separation layer, the hard pressing plate and the cushion layer are torn off; grinding the plate, grinding the excess filler on the circuit board through a grinding device. The present invention solves the problem that there is a lack of a simple process for making the circuit and substrate flush in the prior art, and the flatness is not high after the flushing process.

Description

Technical Field

[0001] The invention relates to the field of PCB manufacturing technology, and in particular to a method for making a circuit and a substrate flush in a PCB process. Background Art

[0002] In the prior art, some products have high requirements on the flatness of the circuit and the substrate (if the contacts or circuits on the PCB need to repeatedly contact the device, the metal surface will wear out to a certain extent as the product works, resulting in poor contact), and require that the substrate area and the circuit area have as little height difference as possible.

[0003] At present, conventional PCB production uses solder mask, which cannot solve the gap between circuits and cannot keep the solder mask flush with the circuits.

[0004] In view of this, this technical solution proposes a method for making the circuit and substrate flush in the PCB process, by post-pressing PP glue (epoxy resin), and then pressing and grinding with a grinding disc, finally obtaining a product where the substrate and circuit are flush. The process is simple, does not change the conventional pre-process, is easy to implement, and has a high final flatness. Summary of the invention

[0005] 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 method for making the circuit and substrate flush in the PCB process, aiming to solve the problem that there is a lack of a simple circuit and substrate flush manufacturing process in the prior art, and the flatness is not high after the flush process.

[0006] To achieve the above object, the present invention provides a method for making a circuit and a substrate flush in a PCB process, comprising the following steps:

[0007] Filling layer setting: setting filling layers on both sides of the circuit board that has been completed through the circuit manufacturing process, wherein the filling layers include a cushion layer, and a hard pressing plate, a separation layer and a mosaic layer stacked in sequence from the cushion layer toward the surface of the circuit board;

[0008] Filling layer lamination: the filling layers on both sides are pressed toward the circuit board by a lamination device, so that the interlocking layer fills the gap of the circuit board, and then the separation layer together with the hard pressing plate and the cushion layer are torn off;

[0009] Grinding the board: Grinding the excess filler on the circuit board by using a grinding device.

[0010] As a further solution of the present invention, before the step of setting the filling layer, the copper surface of the circuit board is browned, and then baked at a temperature of 120° C. for 2 hours.

[0011] As a further solution of the present invention, the mosaic layer is a PP adhesive layer.

[0012] As a further solution of the present invention, the hard pressing plate is a steel plate with a smooth surface.

[0013] As a further solution of the present invention, the cushion layer is a kraft paper laminated structure.

[0014] As a further solution of the present invention, the separation layer is a release film.

[0015] As a further solution of the present invention, the circuit manufacturing process before the filling layer setting step includes:

[0016] Cut the production board to a fixed size using a cutting machine;

[0017] The required pattern is transferred to the board through coating and exposure of the printed circuit, and then the pattern is obtained by etching;

[0018] Check whether there are defects in the PCB circuit through optical inspection;

[0019] The copper surface of the PCB board is roughened by browning solution to enhance the bonding strength between the copper surface and PP;

[0020] Each PCB substrate is combined and pressed into a multi-layer PCB through a press machine;

[0021] Through the target holes designed between the graphics, a multi-layer PCB board is aligned, and the target holes are drilled for subsequent alignment;

[0022] Use a drill to drill holes in the designed pattern to form vias between layers;

[0023] Copper is deposited in the hole and its surface by chemical copper deposition, and then a layer of copper is plated on the hole by PTH electroplating;

[0024] Use resin to plug the plated holes, and then remove the excess resin with a ceramic grinding plate;

[0025] The required pattern is transferred to the board through coating and exposure of the printed circuit, and then the pattern is obtained by etching.

[0026] The beneficial effects of the present invention are as follows:

[0027] The method for making the circuit and substrate flush in the PCB process proposed by the present invention effectively fills the gap between the circuit and the substrate by adopting a manufacturing method with embedding and pressing, and then grinds the excess area by grinding the plate, finally leaking the circuit. This method can replace the manufacturing method using solder mask, and effectively solves a series of problems encountered by products requiring the flushness of the circuit and the substrate. The process is simple, the adaptability is strong, and no changes are made to the existing circuit board pre-processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 This is a schematic diagram of the interlocking layer (PP glue) filling the gap after implementing this solution.

[0030] Figure 2 It is a schematic diagram of the leveling process and the overall pre-process flow of the present invention.

[0031] Figure 3 It is a schematic diagram of the circuit board in the present invention after the filling layer is set.

[0032] Figure 4 It is a schematic diagram of the main process flow of the present invention. DETAILED DESCRIPTION

[0033] as follows:

[0034] Please see attached Figure 1-4 ,

[0035] The main implementation steps are: filling layer setting, setting filling layers on both sides of the circuit board that has been completed through the circuit manufacturing process, the filling layers include a cushion layer, and a hard pressing plate, a separation layer and a mosaic layer stacked in sequence on the cushion layer toward the surface of the circuit board; filling layer lamination, pressing the filling layers on both sides toward the circuit board through a lamination device, so that the mosaic layer fills the gaps in the circuit board, and then the separation layer together with the hard pressing plate and cushion layer are torn off; grinding, grinding the excess filler on the circuit board through a grinding device.

[0036] Process principle:

[0037] PP glue (epoxy resin) is used as an ideal material for embedding into the gap due to its flowable and curing properties. Combined with the padding layer, hard pressing plate and separation layer of the filling layer, the two sides of the circuit board can be kept flat during lamination, and the embedding layer can be fully filled into the gap between the circuit and the substrate as much as possible to make its surface flat. Compared with the current direct grinding, solder mask and other processes, this solution has the characteristics of easy material acquisition, simple setting, good filling effect and low pollution without changing the overall manufacturing process of the circuit board. Among them, the role of the padding layer is to maintain uniform force during lamination; the role of the hard pressing plate is to maintain the force to support the flatness of the lamination; and the role of the separation layer is to prevent the circuit board from adhering to the hard pressing plate at the bottom after lamination.

[0038] A preferred embodiment of the present invention is as follows: before the step of setting the filling layer, the copper surface of the circuit board is browned, and then baked at a temperature of 120° C. for 2 hours.

[0039] The purpose of baking is to remove moisture and increase the adhesion of the circuit board surface.

[0040] A preferred embodiment of the present invention: the mosaic layer is a PP adhesive layer.

[0041] As a mosaic layer, the PP adhesive layer is widely available, low cost, and has good flow, curing and properties, making it an excellent filler.

[0042] A preferred embodiment of the present invention is that the hard pressing plate is a steel plate with a smooth surface.

[0043] The main purpose of using steel plate as the hard pressure plate is to use a harder plate as pressure support and to apply flat pressure.

[0044] A preferred embodiment of the present invention is that the cushion layer is a laminated structure of kraft paper.

[0045] This solution uses at least 20 layers of kraft paper as a cushion layer to evenly distribute the pressure during pressing.

[0046] A preferred embodiment of the present invention: the separation layer is a release film.

[0047] The release film prevents the circuit board from adhering to the bottom steel plate after lamination, which affects the final filling effect.

[0048] A preferred embodiment of the present invention includes: the circuit manufacturing process before the step of setting the filling layer includes: cutting the production board size to a fixed size by a cutting machine; transferring the required pattern to the board material by coating and exposing the printed circuit, and then obtaining the pattern by etching; checking whether the PCB board circuit has defects by optical detection; roughening the copper surface of the PCB board by browning solution to enhance the bonding force between the copper surface and PP; combining each PCB substrate by a press to press into a multi-layer PCB; forming a multi-layer PCB board alignment by designing target holes between the patterns, and drilling the target holes as a subsequent alignment; drilling the holes of the designed pattern by a drill to form a conductive hole between each layer; depositing copper on the hole and its surface by chemical copper deposition, and then plating a layer of copper on the hole by PTH electroplating; plugging the plated hole with resin, and then removing the excess resin by a ceramic grinding plate; transferring the required pattern to the board material by coating and exposing the printed circuit, and then obtaining the pattern by etching.

[0049] This solution does not change the pre-process of the circuit board before the filling layer setting step, has strong adaptability, and the pre-process of the circuit board can be the currently more existing circuit board processing technology.

[0050] 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 making a circuit and a substrate flush in a PCB process, characterized in that: The following steps are involved: S1, fill layer settings, A filling layer is arranged on both sides of the circuit board that has been completed through the circuit manufacturing process, wherein the filling layer includes a cushion layer, and a hard pressing plate, a separation layer and a mosaic layer stacked in sequence on the cushion layer toward the surface of the circuit board; S2, filling layer lamination, The filling layers on both sides are pressed toward the circuit board by a pressing device, so that the interlocking layer fills the gap of the circuit board, and then the separation layer together with the hard pressing plate and the cushion layer are torn off; S3, grinding plate, The redundant filler on the circuit board is ground flat by a grinding device.

2. The method for making the circuit and substrate flush in the PCB process according to claim 1, characterized in that: Before the step of setting the filling layer, the copper surface of the circuit board is browned, and then baked at 120° C. for 2 hours.

3. The method for making the circuit and substrate flush in PCB process according to claim 1, characterized in that: The mosaic layer is a PP adhesive layer.

4. The method for making the circuit and substrate flush in PCB process according to claim 1, characterized in that: The hard pressing plate is a steel plate with a smooth surface.

5. The method for making the circuit and substrate flush in PCB process according to claim 1, characterized in that: The cushion layer is a kraft paper laminated structure.

6. The method for making the circuit and substrate flush in PCB process according to claim 1, characterized in that: The separation layer is a release film.

7. The method for making the circuit and substrate flush in PCB process according to claim 1, characterized in that: The circuit manufacturing process before the filling layer setting step includes: A1. Use a cutting machine to cut the production board into fixed sizes; A2. Transfer the required pattern to the board through coating and exposure of printed circuits, and then obtain the pattern by etching; A3. Check whether there are defects in the PCB circuit through optical inspection; A4. Roughen the copper surface of the PCB board with browning solution to enhance the bonding strength between the copper surface and PP; A5. Combine each PCB substrate through a press to form a multi-layer PCB. A6. Through the target holes designed between the graphics, a multi-layer PCB board is formed for alignment, and the target holes are drilled for subsequent alignment; A7. Use a drill to drill the holes of the designed pattern to form vias between layers; A8. Use chemical copper deposition to deposit copper in the hole and its surface, and then plate a layer of copper on the hole through PTH electroplating; A9. Use resin to plug the holes that have been electroplated, and then remove the excess resin with a ceramic grinding plate; A10. Transfer the required pattern to the board through coating and exposure of printed circuits, and then obtain the pattern through etching.

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