CN105376941A - Printed circuit board processing method - Google Patents

Abstract

The invention discloses a processing method of a printed circuit board, which comprises the following steps: exposure, development, copper plating and drilling, and provides a processing method of a printed circuit board with a high qualification rate of secondary drilling. Compared with the related technology, the processing method of the printed circuit board provided by the present invention, by setting the plated hole film at the position of the target hole area of the printed circuit board to block light, after exposure and development steps, the target hole area If exposed, a copper layer is evenly plated on the target hole area to improve the positioning accuracy of the X-ray machine when it is transmitted through light, reduce the deviation between the primary drilling and the secondary drilling, and improve the pass rate of the printed circuit board.

Description

Processing method of printed circuit board

technical field

The invention relates to the technical field of printed circuit board processing, in particular to a method for processing a printed circuit board.

Background technique

In the manufacturing process of printed circuit boards (Printed Circuit Board, PCB), through holes are needed to realize the electrical connection between the layers of the inner circuit board. Finally, a through hole for electrical connection needs to be formed, and the through hole is electroplated with copper to form a conductive layer to realize electrical connection, and then the through hole is used as a plug hole for protection. However, when electroplating copper for through holes that need to be electrically connected, there is a sputtering phenomenon, which causes a layer of copper with uneven thickness to be sputtered on the target holes that need to be insulated, which affects the reliability of the circuit. The insulated target hole is drilled twice to remove the sputtered copper layer and improve the pass rate in the process of PCB board processing.

However, because the thickness of the sputtered copper layer of the target hole that needs to be insulated is different, there is a shadow in the picture produced by the X-ray machine during the light transmission process when the hole is drilled again, so that the X-ray machine cannot accurately capture the target hole. center, resulting in a displacement difference between the two drilling holes before and after, which further affects the qualification rate of the PCB board.

Therefore, it is necessary to provide a new method for processing printed circuit boards to solve the above technical problems.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned technical problems and provide a method for processing printed circuit boards with a high pass rate of secondary drilling.

The invention provides a method for processing a printed circuit board, comprising:

Provide printed circuit boards to be processed, including photosensitive dry films pre-attached on both sides and target holes after a drilling process; X-ray machine, used for drilling positioning of the printed circuit boards to be processed; plated holes The film is used for opening windows on both sides of the printed circuit board to be processed; the electroplating equipment is used for copper plating the printed circuit board to be processed;

Exposure: sticking the plated hole film on the photosensitive dry film of the printed circuit board to be processed, and performing light blocking treatment on the target hole area, and then exposing the plated hole film;

Developing: developing the printed circuit board to be processed until the target hole of the printed circuit board to be processed is exposed;

Copper plating: uniform copper plating on the target hole area by the electroplating equipment;

Drilling: use the X-ray machine to perform light-transmitting positioning on the target hole area after the copper plating step and perform secondary drilling.

Preferably, the target hole area is a rectangular area centered on the target hole with a side length of 3-9 mm.

Preferably, the dry film components include: binder, monomer, initiator and photosensitive resin.

Compared with the related technology, the processing method of the printed circuit board provided by the present invention, by setting the plated hole film at the position of the target hole area of the printed circuit board to block light, after exposure and development steps, the target hole area If exposed, a copper layer is evenly plated on the target hole area to improve the positioning accuracy of the X-ray machine when it is transmitted through light, reduce the deviation between the primary drilling and the secondary drilling, and improve the pass rate of the printed circuit board.

Description of drawings

Fig. 1 is the schematic flow sheet of the processing method of printed circuit board of the present invention;

FIG. 2 is a schematic structural diagram of the printed circuit board in FIG. 1 .

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Please refer to FIG. 1 and FIG. 2 at the same time, wherein FIG. 1 is a schematic flow chart of the processing method of the printed circuit board of the present invention; FIG. 2 is a schematic structural diagram of the printed circuit board in FIG. 1 . The invention provides a method for processing a printed circuit board, comprising:

Step S1:

Provide a printed circuit board 1 to be processed, including a photosensitive dry film 13 pre-attached on both sides thereof and a target hole 11 after a drilling process;

X-ray machine, used for drilling positioning of the printed circuit board 1 to be processed;

A film with plated holes, which is used to open windows on both sides of the printed circuit board 1 to be processed;

Electroplating equipment, used for copper plating the printed circuit board 1 to be processed;

Step S2: Exposure

Pasting the plated hole film on the photosensitive dry film 13 of the printed circuit board 1 to be processed, and performing light blocking treatment on the target hole area 12, and then exposing the plated hole film; the exposing step S2 Under the irradiation of light of a specific spectrum, the color of the dry film 13 in the non-blocking area of the film becomes darker and then hardens, tightly protecting the copper foil on the surface of the printed circuit board 1 to be processed, and printing the copper foil on On the printed circuit board 1 to be processed. The dry film 13 is a photopolymerizable dry film. In this embodiment, the light of a specific spectrum is ultraviolet rays.

Step S3: Developing

The printed circuit board 1 to be processed is subjected to developing treatment until the target hole 11 of the printed circuit board 1 to be processed is exposed; the developing step S3 washes off the unhardened dry film by sodium carbonate solution 13 , exposing the copper foil without the protection of the dry film 13 , and then etching the printed circuit board 1 with a copper etching solution to etch the copper foil without the protection of the dry film 13 . The copper foil under the protection of the dry film 13 forms the circuit pattern on the printed circuit board 1 .

Step S4: Copper plating

Uniform copper plating for the target hole area 12 by the electroplating equipment;

Step S5: Drilling

Through the X-ray machine, the target hole area 12 after the copper plating step is subjected to light-transmitting positioning and secondary drilling.

The target hole area 12 is because the light is blocked by the film in the exposure step S2, and the copper foil is etched clean by the copper etching solution in the developing step S3, so that the copper plating step After S4 is completed, the target hole area 12 satisfies the uniform copper thickness and the clear light transmission screen of the X-ray machine, so as to realize the precise grasping of the center of the target position.

After the target hole 11 of the printed circuit board 1 to be processed is drilled for the first time, the target hole 11 is copper plated, and the conductive layer formed in the target hole 11 is used to realize the connection between the multilayer circuit boards. electrical connection. The target hole area 12 and the light-blocking area provided by the film to match the target hole area 12 are both rectangular areas with the target hole 11 as the center and a side length of 3-9 mm.

Compared with the related technology, the processing method of the printed circuit board provided by the present invention, by setting the plated hole film at the position of the target hole area of the printed circuit board to block light, after exposure and development steps, the target hole area If exposed, a copper layer is evenly plated on the target hole area to improve the positioning accuracy of the X-ray machine when it is transmitted through light, reduce the deviation between the primary drilling and the secondary drilling, and improve the pass rate of the printed circuit board.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (3)

1. A processing method for a printed circuit board, characterized in that, comprising: Provide a printed circuit board to be processed, an X-ray machine, a plated hole film and electroplating equipment, wherein the printed circuit board to be processed includes a photosensitive dry film pre-attached on both sides and a target hole after a drilling process, so The X-ray machine is used for drilling and positioning the printed circuit board to be processed, the plated film is used to open windows on both sides of the printed circuit board to be processed, and the electroplating equipment is used to open the window on the printed circuit board to be processed. Copper plating on printed circuit boards; Exposure: sticking the plated hole film on the photosensitive dry film of the printed circuit board to be processed, and performing light blocking treatment on the target hole area, and then exposing the plated hole film; Developing: developing the printed circuit board to be processed until the target hole of the printed circuit board to be processed is exposed; Copper plating: uniform copper plating on the target hole area by the electroplating equipment; Drilling: use the X-ray machine to perform light-transmitting positioning on the target hole area after the copper plating step and perform secondary drilling. 2 . The method for processing a printed circuit board according to claim 1 , wherein the target hole area is a rectangular area centered on the target hole and with a side length of 3-9 mm. 3 . 3 . The method for processing printed circuit boards according to claim 1 , wherein the dry film components include a binder, a monomer, an initiator and a photosensitive resin. 4 .