CN110519917B

CN110519917B - Method for manufacturing through hole

Info

Publication number: CN110519917B
Application number: CN201910795486.5A
Authority: CN
Inventors: 徐世明; 王健; 金慧贞; 孙彬; 沈洪; 李晓华
Original assignee: Jiangsu Shangda Electronics Co Ltd
Current assignee: Jiangsu Shangda Electronics Co Ltd
Priority date: 2019-08-27
Filing date: 2019-08-27
Publication date: 2021-08-17
Anticipated expiration: 2039-08-27
Also published as: CN110519917A

Abstract

The invention relates to a manufacturing method of a through hole, and belongs to the technical field of printed circuit boards. The method comprises the following steps: coating photoresist on two sides of an insulating film, carrying out two-side exposure and development on the insulating film coated with the photoresist, carrying out two-side etching on the insulating film after development to form a concave groove, coating the photoresist on two sides of the etched insulating film, carrying out exposure and development on the film coated with the photoresist, carrying out two-side etching on the insulating film subjected to secondary exposure and development to form a step-shaped through hole, carrying out film removal treatment on the insulating film coated with the photoresist on two sides and provided with the step-shaped through hole, carrying out copper plating on the film-removed insulating film, and completing electroplating to form the step-shaped through hole. The invention has the beneficial effects that: the phenomena of needle breakage, drilling deviation and the like are avoided; the residual glue or copper slag generated by drilling is reduced; etching the two sides simultaneously to ensure the quality of the holes; the stepped hole is formed, so that circulation of electroplating solution in subsequent copper plating is facilitated, and the quality of hole copper can be better guaranteed.

Description

Method for manufacturing through hole

Technical Field

The invention relates to a manufacturing method of a through hole, and belongs to the technical field of printed circuit boards.

Background

With the continuous development and innovation of electronic products and technologies, the design concept of electronic products gradually trends to be light, thin, short and small, and the design of Printed Circuit Boards (PCBs) also develops towards small aperture, high density, multiple layers and thin lines. The thickness-diameter ratio of the through hole of the product is obviously increased along with the reduction of the aperture of the increase of the layer thickness of the circuit board, the PTH processing difficulty is gradually increased, and the phenomenon of metal thinness or no metal phenomenon in the hole is easily caused.

The critical steps of the via fabrication process are opening and copper electroplating. The hole opening process has different effects according to different thickness-diameter ratios of holes, and the copper deposition process has great defects in cost and environmental protection, and has the following main defects:

1. as the pore size decreases, it becomes more difficult to treat the residual colloid and copper dross in the pores, and repeated mechanical and chemical treatments tend to not only affect the pore size, but also deform the plate. And may even result in scrap, increasing manufacturing costs.

2. Under the condition of drilling deep holes, the problem of broken pins possibly occurs in mechanical drilling, the quality requirement cannot be met, and meanwhile, the processing cost is increased

3. After drilling, as the PI base materials are connected between the copper foils and conduction cannot be realized, a layer of copper is deposited on the surface of the through hole in a chemical mode, and chemical copper deposition liquid medicine containing a large amount of formaldehyde can also affect the environment.

4. When the copper is electroplated, the copper in the holes is very thin, and meanwhile, due to the limitation of the too small deep plating capacity and the too small aperture of the liquid medicine, the deposition rate in the holes is relatively low in the electroplating process, so that more copper can be deposited on the surface of the printed circuit board, and the manufacturing cost is indirectly increased.

5. In the same deep hole electroplating process, the thickness-diameter ratio is large, so that the electroplating solution is not circulated uniformly in the process, and the problems of low hole copper quality and poor reliability are caused.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for manufacturing a through hole. By the method, the uniform circulation of the electroplating solution can be realized, and the quality of the hole copper can be well ensured.

The invention is realized by the following technical scheme: a method of manufacturing a via hole, comprising:

step 1: coating photoresist I on two sides of the insulating film;

step 2: exposing and developing the two sides of the insulating film coated with the photoresist I;

and step 3: etching two sides of the developed insulating film to form a concave groove;

and 4, step 4: coating photoresist II on two surfaces of the etched insulating film;

and 5: exposing and developing the film coated with the photoresist II;

step 6: etching both sides of the insulating film subjected to secondary exposure and development to form a step-shaped through hole;

and 7: removing the film of the insulating film coated with the photoresist on two sides and provided with the step-shaped through hole;

and 8: and (4) plating copper on the stripped insulating film to finish electroplating and form the stepped through hole.

The insulating film is made of polyimide material, epoxy resin material or polyurethane material.

The step through hole is a round hole or a square hole or a round hole plus a square hole.

The step number of the step through hole is two steps or multiple steps.

The invention has the beneficial effects that: 1. The step hole is formed on the insulating film by an etching method, so that the phenomena of needle breakage, deviation in drilling and the like which can occur in the conventional mechanical drilling are avoided.

2. The problem of poor hole copper quality caused by residual glue or copper slag generated by traditional mechanical drilling is solved.

3. The two sides are etched simultaneously, so that compared with the traditional process of drilling from a single side, the process is more convenient and time-saving, and meanwhile, the quality of holes can be ensured.

4. The stepped hole is formed, so that circulation of electroplating solution in subsequent copper plating is facilitated, and the quality of hole copper can be better guaranteed.

Drawings

The invention is further illustrated below with reference to the figures and examples.

FIG. 1 is a schematic view of step 1 of the present invention;

FIG. 2 is a schematic diagram of step 2 of the present invention;

FIG. 3 is a schematic diagram of step 3 of the present invention;

FIG. 4 is a schematic diagram of step 4 of the present invention;

FIG. 5 is a schematic diagram of step 5 of the present invention;

FIG. 6 is a schematic diagram of step 6 of the present invention;

FIG. 7 is a schematic diagram of step 7 of the present invention;

FIG. 8 is a schematic diagram of step 8 of the present invention.

In the figure: 1. insulating film, 2, photoresist I, 3, concave groove, 4, photoresist II, 5, through hole, 6, ladder through hole.

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.

Referring to fig. 1 to 8, a method for manufacturing a via hole includes:

step 1: coating photoresist I2 on two sides of the insulating film 1;

step 2: exposing and developing the two sides of the insulating film 1 coated with the photoresist I2 to expose the part to be etched;

and step 3: etching two sides of the developed insulating film 1 to etch two concave grooves 3 similar to blind holes;

and 4, step 4: coating photoresist II 4 on two surfaces of the etched insulation film 1;

and 5: exposing and developing the film coated with the photoresist II 4, and exposing a part to be etched on the concave groove 3;

step 6: etching two sides of the exposed part of the concave groove 3 of the insulating film 1 after the secondary exposure and development to form a step-shaped through hole 5;

and 7: removing the film of the insulating film 1 coated with the photoresist on two sides and provided with the step-shaped through hole 5;

and 8: and (3) plating copper on the film-removed insulating film 1 to finish electroplating, and blocking the stepped through hole 5 by the plating layer to form a stepped through hole 6.

The insulating film 1 is made of polyimide material, epoxy resin material or polyurethane material.

The stepped through hole 6 is a round hole or a square hole or a round hole plus a square hole.

The step number of the step through hole 6 is two steps or multiple steps.

The beneficial effects of the embodiment are:

first, the formation of the step hole is realized on the insulating film 1 by an etching method, so that the phenomena of needle breakage, deviation of drilling and the like which may occur in the conventional mechanical drilling are avoided.

And secondly, the problem of low hole copper quality caused by residual glue or copper slag generated by the traditional mechanical drilling is solved.

And secondly, the two sides of the insulating film 1 are etched simultaneously, so that compared with the traditional process of drilling from a single side, the process is more convenient and time-saving, and meanwhile, the quality of holes can be ensured.

Finally, the formation of the step-shaped through hole 5 is beneficial to the circulation of electroplating solution in the subsequent copper plating process, thereby better ensuring the quality of hole copper.

Claims

1. A method of manufacturing a via hole, comprising:

step 1: coating a photoresist I (2) on two sides of an insulating film (1);

step 2: exposing and developing the two sides of the insulating film (1) coated with the photoresist I (2);

and step 3: etching both sides of the developed insulating film (1) to form a concave groove (3);

and 4, step 4: coating photoresist II (4) on two surfaces of the etched insulating film (1);

and 5: exposing and developing the film coated with the photoresist II (4);

step 6: etching both sides of the insulating film (1) subjected to secondary exposure and development to form a step-shaped through hole (5);

and 7: removing the film of the insulating film (1) coated with the photoresist on two sides and provided with the step-shaped through hole (5);

and 8: and (4) plating copper on the stripped insulating film (1) to finish electroplating, and forming a stepped through hole (6).

2. The method of manufacturing a via according to claim 1, wherein: the insulating film (1) is made of polyimide material, epoxy resin material or polyurethane material.

3. The method of manufacturing a via according to claim 1, wherein: the stepped through hole (6) is a round hole or a square hole or a round hole plus a square hole.

4. The method of manufacturing a via according to claim 1, wherein: the step number of the step through hole (6) is two steps or multiple steps.