CN115835538A

CN115835538A - Manufacturing method of PCB with symmetrical stacking design

Info

Publication number: CN115835538A
Application number: CN202211485027.5A
Authority: CN
Inventors: 李志雄
Original assignee: Chengyi Electronics Jiaxing Co ltd
Current assignee: Chengyi Electronics Jiaxing Co ltd
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2023-03-21

Abstract

The invention belongs to the technical field of PCB manufacturing, and particularly relates to a manufacturing method of a PCB with a symmetrical stacking design, which solves the problem of unstable high-frequency signals caused by uneven thickness of electroplated copper and the fact that the thickness of a high-frequency layer is thinner by 0.1mm by introducing a symmetrical pressing auxiliary layer; the method combines the single-layer high-frequency layer Core board in the conventional PCB manufacturing process into the four-layer high-frequency layer Core board through the auxiliary layer Core board, and the four-layer high-frequency layer Core board after combination is thick in board thickness during electroplating, so that the four-layer high-frequency layer Core board has enough strength to overcome the problem of uneven surface copper thickness after electroplating caused by spraying and water flow; according to the method, before the second pressing, resin is filled in the through holes of the two groups of substrates, so that after the two groups of substrates are pressed, the problem of high-frequency signal instability caused by short circuit due to PP glue overflow can be effectively solved.

Description

Manufacturing method of PCB with symmetrical stacking design

Technical Field

The invention relates to the technical field of PCB manufacturing, in particular to a manufacturing method of a PCB with a symmetrical stacking design.

Background

With the advent of the 5G era, the signal frequency of electronic equipment is designed to be higher and higher, and for example, the frequency reaches 3000-5000mhz by taking a mobile base station auxiliary system as an example. The high-frequency PCB serves as a carrier of electronic equipment components and plays an important role in the aspect of high-frequency signal integrity. For control high frequency subsection PCB is even, antenna layer and antenna layer adjacent shielding layer adopt high frequency material, whole PCB board stack structure symmetry, this PCB board L1 and L8 layer are the high frequency signal layer, and this design mainly has two protrusion problems in PCB board manufacturing process:

1. the thickness of the high-frequency layer is 0.1mm, and the board is easily affected by spraying, water flow and the like during electroplating, so that the copper thickness of the surface after electroplating is uneven, and further, the size is different during etching and manufacturing an antenna pattern, so that the stability of a PCB (printed circuit board) during use for receiving and transmitting signals is affected;

2. after the symmetrical stack design is pressed by the L1-L4 and the L5-L8, glue overflows from the through hole PP on the surfaces L1 and L8, which directly causes short circuit of the component and influences the stability of the signal.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for manufacturing a PCB with a symmetrical stacking design, which solves the technical problems.

In order to achieve the purpose, the invention provides the following technical scheme:

a manufacturing method of a PCB with a symmetrical stacking design comprises the following steps:

s1, selecting four high-frequency Core plates, wherein each high-frequency Core plate is composed of a layer of high-frequency laminate, a layer of auxiliary laminate and another layer of high-frequency laminate which are sequentially stacked and connected;

s2, overlapping and bonding every two high-frequency Core plates through bonding sheets to form a group of substrates, and manufacturing inner-layer circuits in each group of substrates;

s3, respectively pressing and bonding two high-frequency Core plates in the two groups of substrates through bonding sheets;

s4, drilling through holes in the two groups of substrates, and conducting the through holes with the electroplated copper on the surface of the high-frequency layer;

s5, filling the resin plug holes into the via holes to prevent the adhesive sheets from overflowing glue from the via holes after high-temperature melting, and respectively manufacturing circuit patterns of two groups of mutually corresponding layers of substrates;

s6, filling and arranging the stacked bonding sheets between the two groups of corresponding layers of the substrates, pressing to form a finished board, drilling holes in the finished board, conducting the two groups of substrates, drilling holes in the two high-frequency Core boards positioned at the top and the bottom of the finished board, and manufacturing circuit patterns on the high-frequency layer boards on the outer sides of the two high-frequency Core boards.

Further, in step S4, the via hole is mechanically drilled, and the surface of the via hole is thickened by chemical deposition.

Further, in step S6, the holes drilled in the finished plate and the holes drilled in the high frequency Core plate are surface-plated, and the surfaces of the holes are thickened by chemical deposition.

Further, the bonding sheet is a pp bonding sheet.

By adopting the technical scheme, the invention has the beneficial effects that:

1. the invention relates to a manufacturing method of a symmetrical HDI 4+4 stacked high-frequency PCB, which solves the problem of high-frequency signal instability caused by the reason that the thickness of a high-frequency layer is thinner by 0.1mm and the thickness of electroplated copper is not uniform by introducing a symmetrical pressing auxiliary layer;

2. the method combines the single-layer high-frequency layer Core board in the conventional PCB manufacturing process into the four-layer high-frequency layer Core board through the auxiliary layer Core board, and the four-layer high-frequency layer Core board after combination is thick in board thickness during electroplating, so that the four-layer high-frequency layer Core board has enough strength to overcome the problem of uneven surface copper thickness after electroplating caused by spraying and water flow;

3. according to the method, before the second pressing, resin is filled in the through holes of the two groups of substrates, so that after the two groups of substrates are pressed, the problem of high-frequency signal instability caused by short circuit due to PP glue overflow can be effectively solved.

Drawings

Fig. 1 is a schematic structural view of a conventional PCB.

FIG. 2 is a schematic structural diagram of two substrates according to the present invention.

Fig. 3 is a schematic structural view of a completed PCB of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

As shown in fig. 1, a conventional method for manufacturing a PCB includes the following steps:

1. the Core1 high-frequency layer completes mechanical drilling and sheet electroplating, and the Core2 layer completes mechanical drilling and then conducts copper electroplating inside the hole and on the surface to manufacture circuit patterns of an L2 layer, an L3 layer and an L4 layer;

2. the manufacturing method of the Core3 and the Core4 is the same as that of the Core1 and the Core2, and the circuit patterns of the L5 layer, the L6 layer and the L7 layer are manufactured by electroplating the thin plate after mechanical drilling;

3. and adhering PP bonding sheets among the Core1, core2, core3 and Core4 layers for pressing to manufacture the circuit patterns of the L1 layer and the L8 layer.

The manufacturing method not only has difficulty in manufacturing the thin plate, but also has difficulty in solving the problem of glue overflow during pressing.

As shown in fig. 2 and 3, the manufacturing method of the present invention is as follows:

1. four high-frequency Core boards complete the inner layer lines L2 and L3 and the lines L6 and L7.

2. Laminating two Core plates at a time to obtain an L1-L4 four-layer plate substrate and an L5-L8 four-layer plate substrate respectively; after mechanical drilling, conducting electrolytic copper plating in the hole and on the surface; then filling resin holes to prevent glue overflow in the holes, and then manufacturing the circuit patterns of L4 and L5 layers.

3. And (3) laminating two sides of the two Core2 plates for the second time, and respectively attaching PP bonding sheets to the two sides of the two Core2 plates to complete laser drilling of the L1-2 layer and the L7-L8 layer and then manufacture of the L1 layer and the L8 layer of circuit patterns.

The process flow of the invention is as follows:

(1) cutting the inner layer: cutting the raw material large substrate into a working size designed before manufacturing;

(2) manufacturing a primary circuit: only manufacturing lines of L2 and L3 layers and inner layers of L6 and L7 layers on four high-frequency Core plates;

(3) inner layer pressing: correspondingly laminating the inner layers of the L2 and the L3 of the manufactured high-frequency Core plate to obtain a substrate, and correspondingly laminating the inner layers of the L6 and the L7 of the manufactured high-frequency Core plate to obtain a second substrate;

(4) drilling, namely drilling a via hole for line connection between layers on the board surfaces of the two substrates respectively;

(5) electroplating: thickening the surface of the via hole to the required requirement in a chemical deposition mode;

(6) resin hole plugging: filling the via hole with resin to prevent glue overflow during the second press;

(7) manufacturing a secondary circuit: only manufacturing L4 and L5 layers of circuits;

(8) secondary pressing: pressing the two prepared substrates L1-4 and L5-8 together;

(9) laser drilling: drilling the via holes of the L1-2 and L7-8 layers;

drilling an outer layer in red: drilling through the through holes L1-4 and L5-8;

\9322: thickening the surface of the via hole in R (9) and R (9) to the required requirement by chemical deposition;

\9323: manufacturing a final L1 layer circuit and a final L8 layer circuit;

\932450: printing insulating ink on the PCB surface by using a silk screen to develop an original figure by exposure;

\9325: printing pattern and character ink on the silk screen on the solder resist ink;

9326: manufacturing the delivery size required by a customer through a CNC (computer numerical control) machine tool;

\9327: checking the open/short circuit of the PCB circuit;

\9328: the appearance inspection meets the requirements of customers.

By adopting the method, L1-L2 and L3-L4 are pressed to press L5-L6 and L7-L8, two symmetrical high-frequency PCB boards can be produced at one time, and the processing flow of the electroplating thin board is directly reduced.

When the four-layer high-frequency layer Core plate is pressed and combined with the Core lamination, resin is needed to plug holes L1-L4 and L5-L8 through holes, and the combined lamination is symmetrical lamination, so that the problem of glue overflow of a copper surface of a PP bonding sheet is solved.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and those skilled in the art should be able to make general changes and substitutions within the technical scope of the present invention.

Claims

1. A manufacturing method of a PCB with a symmetrical stacking design is characterized by comprising the following steps:

2. The method as claimed in claim 1, wherein in step S4, the via hole is mechanically drilled, and the surface of the via hole is thickened by chemical deposition.

3. The method as claimed in claim 2, wherein the holes drilled in the finished board and the holes drilled in the high frequency Core board are surface-plated, and the holes are thickened by chemical deposition in step S6.

4. The method of claim 1, wherein the bonding sheet is a pp bonding sheet.