CN108541139B

CN108541139B - PCB (printed circuit board) via hole manufacturing method and PCB

Info

Publication number: CN108541139B
Application number: CN201810277481.9A
Authority: CN
Inventors: 李建; 杨世勇; 王文剑; 李达林; 余宁; 陈国忠
Original assignee: Shenzhen Threetek Technology Co ltd
Current assignee: Shenzhen Threetek Technology Co ltd
Priority date: 2018-03-31
Filing date: 2018-03-31
Publication date: 2020-04-17
Anticipated expiration: 2038-03-31
Also published as: CN108541139A

Abstract

The invention discloses a method for manufacturing a through hole of a PCB (printed circuit board), which comprises the following steps of: and performing primary drilling on the position of the conducting hole of the PCB, performing primary through hole plating of thick copper on the conducting hole after the primary drilling, performing secondary drilling on the conducting hole plated with thick copper, and performing secondary through hole plating on the conducting hole after the secondary drilling. The embodiment of the invention provides a PCB via hole manufacturing method and a PCB, which can solve the problem that a plated through hole process is difficult to obtain a plated layer with uniform thickness due to poor hole wall flatness after drilling of high-frequency plates such as PI, PTFE and the like so as to improve the reliability and quality of PCB products.

Description

PCB (printed circuit board) via hole manufacturing method and PCB

Technical Field

The invention relates to the field of electronic manufacturing, in particular to a PCB via hole manufacturing method and a PCB.

Background

Along with the high frequency and the fine feature of electronic products, the high frequency Circuit Board and the high end Circuit Board of special substrate in the PCB industry have increased year by year, the high frequency Circuit Board represented by PI (Polyimide) plate and PTFE (polytetrafluoroethylene) plate has been widely popularized and applied, meanwhile, the high frequency Circuit Board has a strict requirement for the flatness of the transmission conductor, especially for the flatness of the hole wall and copper layer, and the high frequency plate such as PI plate and PTFE plate generally has a better toughness, during the process of drilling the plate, the drill needle is easy to pull the substrate, resulting in a poorer flatness after drilling, while the high frequency plate generally has a stronger chemical inertness, the substrate whose hole wall is pulled out is not easy to bite and erode by the liquid medicine, this brings great challenge to the subsequent through hole plating process, and due to poor hole wall flatness, the through hole plating process cannot obtain a plating layer with uniform thickness, which brings great damage to the reliability and quality of the circuit board product.

Disclosure of Invention

The embodiment of the invention provides a PCB via hole manufacturing method and a PCB, which can solve the problem that a plated through hole process is difficult to obtain a plated layer with uniform thickness due to poor hole wall flatness after drilling of high-frequency plates such as PI and PTFE and the like so as to improve the reliability and quality of PCB products.

In a first aspect, a method for manufacturing a via hole of a PCB provided in an embodiment of the present invention includes:

performing primary drilling with a pre-enlarged aperture at the position of the via hole of the substrate;

performing primary through hole plating of thick copper on the through hole after primary drilling;

drilling the conducting hole plated with the thick copper for the second time;

and carrying out secondary through hole plating on the conducting hole after secondary drilling.

In a second aspect, an embodiment of the present invention provides a PCB, where the via hole of the PCB is obtained by the via hole manufacturing method of the first aspect.

According to the PCB via hole manufacturing method and the PCB provided by the embodiment of the invention, the via hole with the aperture larger than the designed aperture is drilled through the pre-large primary drilling, the thick copper plating process is adopted to plate the thick copper on the wall of the pre-large via hole, the secondary drilling is carried out on the via hole plated with the thick copper to obtain the smooth and clean wall, and the secondary through hole plating is carried out on the via hole, so that the via hole conductive copper layer with uniform thickness is obtained, the via hole manufacturing problem of high-frequency plates such as PI, PTFE and the like in the prior art is effectively solved, and the reliability of the PCB substrate is effectively improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic flow chart of a method for forming a PCB via hole according to an embodiment of the present invention;

fig. 2 is a schematic engineering diagram of a method for manufacturing a via hole of a PCB according to an embodiment 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 some, not all, embodiments of the present invention. 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.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

As shown in fig. 1, an embodiment of the present invention provides a method for manufacturing a via hole of a PCB, including the following steps:

step S11, drilling holes in the positions of the through holes of the PCB for a time with a pre-enlarged aperture;

step S12, plating a thick copper through hole on the through hole drilled for the first time;

step S13, secondary drilling is carried out on the through hole plated with thick copper;

step S14, secondary through hole plating is carried out on the through hole after secondary drilling;

through the pre-large primary drilling, the via hole with the aperture larger than the designed aperture is drilled, the thick copper is plated on the wall of the pre-large via hole by adopting the primary thick copper plating via hole process, the via hole plated with the thick copper is drilled for the second time to obtain the smooth and clean wall, and the via hole is plated for the second time to obtain the via hole conductive copper layer with uniform thickness.

As an alternative, the step of drilling a hole with a pre-enlarged aperture means that a via hole with an aperture larger than the actually designed aperture is drilled by adopting a method of increasing the diameter of a drill point;

further, the diameter of the drill point is increased by 0.01 mm-0.02 mm, and a via hole with the diameter 0.01 mm-0.02 mm larger than the actual designed aperture is drilled, wherein the drilling process parameters are set as follows: the rotating speed of the drill point is 120-150 krpm, the needle inserting speed is 0.8-0.4 m/min, and the needle withdrawing speed is 6-10 m/min.

As an alternative, the one-time plated through hole for plating thick copper to the via hole after one-time drilling includes: and carrying out a pattern pasting manufacturing procedure on the PCB subjected to the primary drilling, wherein the pattern pasting manufacturing procedure is used for ensuring that thick copper is only attached to the hole wall of the via hole and the edge of the via hole in the subsequent thick copper plating procedure, and then carrying out a thick copper plating procedure on the PCB subjected to the pattern pasting manufacturing procedure.

As an alternative, the graphic making process includes: and pasting a dry film on the surface of the PCB after the primary drilling, and performing dry film windowing treatment at the position of the through hole, wherein the diameter of the windowing hole is 0.01-0.02 mm larger than the aperture after the primary drilling.

As an alternative, the thick copper plating manufacturing process comprises the following steps: and (3) plating thick copper by adopting large-current and long-time electroplating parameters, wherein the current parameter is 25 asf-35 asf, the electroplating time is 25 min-35 min, and the thickness of the obtained copper plating layer is 15 um-25 um.

As an alternative, the secondary drilling of the thick copper plated via hole comprises: and drilling a through hole with the diameter matched with the actual designed aperture of the through hole by using a drill point with the diameter matched with the actual designed aperture of the through hole, wherein the rotating speed of the drill point is 130-150 krpm, the needle inserting speed is 0.8-0.4 m/min, and the needle withdrawing speed is 5-9 m/min.

As an alternative, the secondary plating through the via hole after the secondary drilling includes: and carrying out secondary through hole plating by adopting a normal fine electroplating process, wherein the current parameter is 16 asf-18 asf, and the electroplating time is 16 min-20 min.

As shown in fig. 2, a schematic engineering drawing of a method for manufacturing a via hole of a PCB according to an embodiment of the present invention is clearly shown in the drawing, which illustrates a via hole manufacturing process according to an embodiment of the present invention, wherein, when a PCB (21) is drilled for one time, a drill point with a larger diameter is selected to drill a hole, thereby obtaining a through hole with a larger diameter than an actually designed hole diameter, and using an actually designed hole diameter d as an example, a larger drill point is selected to drill a hole to obtain a through hole with a diameter of d +0.01mm to 0.02mm, and then a through hole plating process is performed for one time, as described in the foregoing background art, due to the characteristics of a PCB substrate, a hole wall usually fails to obtain a better flatness and a hole wall surface is uneven (not shown in the figure), under such a hole wall condition, a thick copper plating process of plating a through hole for one time is adopted to obtain a copper layer (23) with a thickness of 15um to 25um, and during a copper plating process, a drawing, attaching a dry film 22 to the position of the PCB surface where copper does not need to be attached, then performing a secondary drilling process on the PCB after the through hole is plated for the first time, wherein the diameter of the drill point adopted is the diameter of the drill point required by the designed aperture, the through hole with the designed aperture is drilled, after the second drilling is finished, the next process is the process of plating the through hole for the second time, wherein it needs to be stated that a process of performing micro etching on a copper layer obtained by plating thick copper is generally required in the process of plating the through hole for increasing the roughness of the surface of the copper layer, so that a new copper layer is more easily attached in the process of plating the through hole for the second time, in addition, the dry film 22 added in the process is required to perform leg mold process, and after the two sub-processes are completed, the through hole plating process for the second time can be started, and at the time, the surface of the through hole has good flatness due to the attachment of the thick copper, the secondary through hole plating process can obtain a conductive copper layer which is very flat, smooth and good in copper layer thickness uniformity generally according to conventional plating parameters, the quality of a plated layer of a through hole of a PCB product with a special substrate such as a high frequency substrate is improved in a very limited manner, and the reliability of the product is effectively improved.

The embodiment of the invention provides a PCB, and the through hole of the PCB is obtained by the through hole manufacturing method in the embodiment.

While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for manufacturing a through hole of a PCB is characterized by comprising the following steps:

drilling holes with pre-enlarged apertures at the positions of the through holes of the PCB,

the method comprises the following steps: drilling a via hole with the aperture larger than the actual design aperture by adopting a method of increasing the diameter of a drill point, wherein the diameter of the drill point is increased by 0.01 mm-0.02 mm, and the via hole with the aperture larger than the actual design aperture by 0.01 mm-0.02 mm is drilled;

performing primary through hole plating of thick copper on the via hole after the primary drilling,

the method comprises the following steps: carrying out a pattern pasting manufacturing procedure on the PCB after the primary drilling, wherein the pattern pasting manufacturing procedure is used for ensuring that thick copper is only attached to the hole wall of the via hole and the edge of the via hole in the subsequent thick copper plating procedure,

further comprising: plating thick copper on the PCB subjected to the graphic pasting manufacturing procedure by adopting a large-current and long-time electroplating parameter, wherein the current parameter is 25 asf-35 asf, the electroplating time is 25 min-35 min, and the thickness of the obtained copper plating layer is 15 um-25 um;

secondary drilling is carried out on the PCB after the primary through hole plating,

the method comprises the following steps: selecting a drill point with the diameter matched with the actual designed aperture of the via hole, and drilling a via hole with the diameter consistent with the actual designed aperture of the via hole;

performing secondary through hole plating on the via hole after secondary drilling,

the method comprises the following steps: and carrying out secondary through hole plating by adopting a normal fine electroplating process, wherein the current parameter is 16 asf-18 asf, and the electroplating time is 16 min-20 min.

2. The via hole forming method as claimed in claim 1, wherein said one drilling comprises: the rotating speed of the drill point is 120-150 krpm, the needle inserting speed is 0.8-0.4 m/min, and the needle withdrawing speed is 6-10 m/min.

3. The via hole forming method according to claim 1, wherein said patterning step comprises: and pasting a dry film on the surface of the PCB after the primary drilling, and performing dry film windowing treatment at the position of the through hole, wherein the diameter of the windowing hole is 0.01-0.02 mm larger than the aperture after the primary drilling.

4. The via hole forming method as claimed in claim 1, wherein said secondary drilling comprises: the rotating speed of the drill point is 130-150 krpm, the needle inserting speed is 0.8-0.4 m/min, and the needle withdrawing speed is 5-9 m/min.

5. A PCB characterized in that at least one via hole on the PCB is made by the via hole making method of any of claims 1-4.