CN112188742A

CN112188742A - Manufacturing method of circuit board with back drilling structure with equal size

Info

Publication number: CN112188742A
Application number: CN202011118405.7A
Authority: CN
Inventors: 刘慧民; 蒋引涛; 付陈洲; 周厚梅
Original assignee: Dongguan Somacis Graphic PCB Co Ltd
Current assignee: Dongguan Somacis Graphic PCB Co Ltd
Priority date: 2020-10-19
Filing date: 2020-10-19
Publication date: 2021-01-05

Abstract

The invention relates to a method for manufacturing a circuit board with an equal-size back drilling structure, which is characterized in that a small hole is firstly formed at a corresponding position of the circuit board needing to form a crimping hole, and the aperture of the small hole is between 2/5 and 3/5 of the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a compression joint hole, wherein the depth is controlled to be between 1.05 and 1.35 mm; plating copper with the thickness of 10-15um on the crimping holes and the small holes; then plating copper with the thickness of 25-30um and tin with the thickness of 4-8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the crimping hole by using a back drilling cutter with the size equal to that of the crimping hole, wherein the back drilling depth is controlled to a transition area where the large and small holes are just drilled. The manufacturing method of the circuit board with the large back drilling structure has the advantages of one-time pressing, low cost, high product yield, high yield, accurate control of pressing alignment and flowing glue inflow control.

Description

Manufacturing method of circuit board with back drilling structure with equal size

Technical Field

The invention relates to a circuit board, in particular to a manufacturing method of a circuit board with an equal-size back drilling structure.

Background

With the development of electronic products towards high density and high precision, the same requirements are correspondingly put forward on circuit boards. For example, in circuit boards such as connectors and integrated interfaces, the wiring density is high, and the diameter of the existing back drilling hole cannot be effectively controlled, so that the wiring space is smaller, and the aperture distance is insufficient.

As shown in FIG. 1, in the prior art, a 0.60mm cutter is needed for a back drill of a 0.45 mm-0.8 mm pitch crimp hole, the distance between the hole wall and the hole wall is only 0.20mm, a pair of 3mil/3mil differential lines are arranged, and no space wiring is arranged.

Disclosure of Invention

Aiming at the problems, the invention provides a manufacturing method of a circuit board with a back drilling structure, which solves the technical problem that two lines are drilled away from a crimping hole by the center distance of a 0.37mm finished product aperture-0.8 mm pitch hole.

The invention is realized by the following technical scheme: a manufacturing method of a circuit board with an equal-size back drilling structure comprises the steps of firstly forming a small hole at a corresponding position of a circuit board needing to form a crimping hole, wherein the aperture of the small hole is between 2/5 and 3/5 of the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a compression joint hole, wherein the depth is controlled to be between 1.05 and 1.35 mm; plating copper with the thickness of 10-15um on the crimping holes and the small holes; then plating copper with the thickness of 25-30um and tin with the thickness of 4-8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the crimping hole by adopting a back drilling tool with the size equal to that of the crimping hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening for 1-10 mil.

Furthermore, a small hole of 0.20mm is firstly formed at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife face to manufacture a crimping hole of 0.45mm, wherein the depth is controlled to be 1.05 mm; plating copper with the thickness of 12um on the crimping holes and the small holes; then plating copper with the thickness of 25um and tin with the thickness of 5um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 3 mils.

Furthermore, a small hole of 0.46mm is firstly formed at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a crimping hole by 0.8mm, wherein the depth is controlled to be 1.35 mm; plating copper with the thickness of 15um on the crimping holes and the small holes; then plating copper with the thickness of 30um and tin with the thickness of 8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 7 mils.

The manufacturing method of the circuit board with the large back drilling structure solves the technical difficulty of wiring of the back drilling based on the 0.45mm aperture (0.372mm pore forming) -0.8mm pitch crimping pore, can fully utilize space for wiring, and increases the distance between pore walls.

Drawings

FIG. 1 is a schematic diagram of a prior art circuit board;

FIG. 2 is a schematic diagram of a circuit board of the manufacturing method of the circuit board with the back drilling structure of the same size;

FIG. 3 is a schematic view of the structure after drilling a small hole;

FIG. 4 is a schematic view of the structure of FIG. 3 after drilling a large hole;

FIG. 5 is a schematic diagram of the electroplated structure of FIG. 4;

FIG. 6 is one of the schematic structural views of the back-drilled shape of FIG. 5;

FIG. 7 is a second schematic diagram of the back-drilled shape of FIG. 5;

fig. 8 is a third schematic structural view of the back-drilled shape of fig. 5.

Detailed Description

The present invention will be described in further detail below with reference to specific examples for facilitating understanding of those skilled in the art.

As shown in fig. 2, the schematic diagram of the circuit board manufactured by the method for manufacturing the circuit board with the large back drilling structure of the invention is obvious that a space wiring area is left.

As shown in fig. 2-8, in the method for manufacturing the circuit board with the constant-size back drilling structure, a small hole 10 is firstly formed at a corresponding position of the circuit board 2 needing to form a crimping hole, and the aperture of the small hole 10 is between 2/5 and 3/5 of the crimping hole 11; controlling the depth from the small hole to the knife surface to manufacture a compression joint hole 11, wherein the depth is controlled to be between 1.05 and 1.35 mm; plating a copper layer 3 with the thickness of 5-10um on the crimping hole 11 and the small hole 10; then plating copper with the thickness of 20-25um and tin with the thickness of 4-8um on the pressure welding hole 11 and the small hole 10 (the copper and the tin can be removed after back drilling and etching); and (4) carrying out back drilling processing on the circuit board at the position corresponding to the crimping hole by adopting a back drilling tool with the size equal to that of the crimping hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening for 1-10 mil. Finally, the purpose of back drilling structure with equal size is achieved by etching and stripping tin.

Example one

Firstly, a small hole of 0.20mm is arranged at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife face to manufacture a crimping hole of 0.45mm, wherein the depth is controlled to be 1.05 mm; plating copper with the thickness of 12um on the crimping holes and the small holes; then plating copper with the thickness of 25um and tin with the thickness of 5um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 3 mils.

Example two

Firstly, a small hole of 0.46mm is arranged at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a crimping hole by 0.8mm, wherein the depth is controlled to be 1.35 mm; plating copper with the thickness of 15um on the crimping holes and the small holes; then plating copper with the thickness of 30um and tin with the thickness of 8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 7 mils.

The shapes of the equilarge back drills formed in the manufacturing method of the circuit board with the equilarge back drill structure are three, and as shown in fig. 6, bulges with triangular sections are formed by transition between the back drills and the crimping holes. As shown in fig. 7, the transition between the back drill and the crimp hole forms a protrusion with a trapezoidal or square cross-section. The transition between the back drill and the crimp hole may be straight through, as shown in fig. 8. And may be selected according to the accuracy of the machining process.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes in the embodiments and modifications thereof may be made, and equivalents may be substituted for elements thereof; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A manufacturing method of a circuit board with an equal-size back drilling structure is characterized by comprising the following steps: firstly, a small hole is arranged at the corresponding position of the circuit board needing to form the crimping hole, and the aperture of the small hole is between 2/5 and 3/5 of the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a compression joint hole, wherein the depth is controlled to be between 1.05 and 1.35 mm; plating copper with the thickness of 10-15um on the crimping holes and the small holes; then plating copper with the thickness of 25-30um and tin with the thickness of 4-8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the crimping hole by adopting a back drilling tool with the size equal to that of the crimping hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening for 1-10 mil.

2. The method for manufacturing the circuit board with the constant-size back drilling structure according to claim 1, wherein the method comprises the following steps: firstly, a small hole of 0.20mm is arranged at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife face to manufacture a crimping hole of 0.45mm, wherein the depth is controlled to be 1.05 mm; plating copper with the thickness of 12um on the crimping holes and the small holes; then plating copper with the thickness of 25um and tin with the thickness of 5um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 3 mils.

3. The method for manufacturing the circuit board with the constant-size back drilling structure according to claim 1, wherein the method comprises the following steps: firstly, a small hole of 0.46mm is arranged at the corresponding position of the circuit board needing to form the crimping hole; controlling the depth from the small hole to the knife surface to manufacture a crimping hole by 0.8mm, wherein the depth is controlled to be 1.35 mm; plating copper with the thickness of 15um on the crimping holes and the small holes; then plating copper with the thickness of 30um and tin with the thickness of 8um on the crimping holes and the small holes; and (4) carrying out back drilling processing on the circuit board at the position corresponding to the compression joint hole by using a back drilling tool with the size equal to that of the compression joint hole, controlling the back drilling depth to a transition area where the large and small holes are drilled, and then deepening by 7 mils.