KR20000058361A - The method of forming circuit on circuit board by laser and laser mask - Google Patents

Abstract

PURPOSE: A method for forming a circuit of a circuit board is provided to reduce inferior articles and production process by using laser and laser mask. CONSTITUTION: A bottom panel(25) is made of laser transparent material such as fused silica. A copper plate(14) is placed on the bottom panel(25). A laser mask having circuit pattern coat(26) formed of laser reflecting material is placed on the copper plate(14) in one side of the bottom panel(25). The laser reflecting material is at least one selected from group including dielectrics, oxides, fluorides, sulfides, Au, Ag, Al, Ni-Cr, Si, Ge, etc. The laser mask is arranged in parallel with the surface of the copper plate(14) with a predetermined distance, and laser is irradiated onto the copper plate. The melted copper is removed by compressed air from a blower, thereby forming a circuit on the surface of the copper plate(14).

Description

The method of forming circuit on circuit board by laser and laser mask}

The present invention relates to a circuit forming method of a circuit board. Unlike the conventional circuit forming method of a printed circuit board (PCB) manufacturing method, the use of a laser and a laser mask in forming a circuit of a circuit board reduces the occurrence of defective products and chemicals. The present invention relates to a method for forming a circuit board of a circuit board by using a laser and a laser mask, which can solve environmental problems caused by the use of chemicals, as well as reduce costs and increase production by shortening a manufacturing process.

1 shows a circuit forming process of a PCB manufacturing method which is widely used at present. Referring to the drawings, a conventional technique is as follows.

As shown in FIG. 1A, in order to improve adhesion between the copper foil and the photosensitive dry film in the laminating process, an oxide film, an oily fat, and the like on the surface of the copper foil attached to the substrate are removed and a constant roughness is given.

As shown in FIG. 1B, the dry film is pressed with a heated roller to closely adhere to the surface of the copper foil adhered to the substrate. (Laminating step)

As shown in FIG. 1C, the exposure film is placed on the dry film to selectively photocure the dry film portion to form a circuit pattern by irradiating UV.

As shown in FIG. 1D, the dry film (the photocured dry film portion) not exposed to UV in the exposure process is dissolved in a developer and removed.

As shown in FIG. 1E, the exposed copper foil is etched with a corrosion solution to form a circuit pattern. At this time, the dry film portion remaining after photocuring acts as an etching resist to form a circuit (corrosion process).

As shown in FIG. 1F, the dry film remaining after photocuring on the circuit formed on the surface of the copper foil through the corrosion process is peeled off using a peeling solution.

The circuit formation method of the conventional PCB manufacturing method takes a number of processes and takes some time to manufacture, and defective products are generated due to processing problems in each process, and also various kinds of chemicals are used. Is causing. The processing problems are as follows for each process. The laminating process is a preparation process for forming a circuit. The photosensitive dry film is closely attached to the surface of the copper foil adhered to the front substrate. In this process, if the dry film is not completely adhered to the copper foil, the copper foil portion that forms the circuit in the corrosion process is formed. Corrosion generates defective products. The exposure process is a process of placing an exposure film on a dry film and irradiating UV to photocuring a circuit part. When foreign materials such as dust are on the exposure film or dry film, unnecessary parts other than a circuit pattern are photocured to generate defective products. In addition, in the corrosion process, over-corrosion or non-corrosion occurs due to non-uniformity of corrosion rate, resulting in defective products. Next, when looking at the environmental problems caused by the use of various kinds of chemicals, there are environmental risks because a variety of chemicals are used in the developing process, the corrosion process, and the peeling process.

The present invention has been made for the purpose of solving the conventional problems as described above to form a circuit of a circuit board using a laser and a laser mask to achieve this object.

1A, 1B, 1C, 1D, 1E, and 1F are the main process diagrams of the conventional method.

2A and 2B are main process diagrams of the present invention.

※ Explanation of code for main part of drawing

Cross section of copper foil with 1 roughness

2 copper foil cross section

3 Board Cross Section

4 roller cross section

5 roller rotation direction

6 dry film single sided

7 Board Progress Direction

8 UV

9 Parts other than circuit pattern of film for exposure

10 Circuit pattern part of film for exposure

11 Uncured dry film cross section

12 Photo-cured dry film cross section

13 Dry film cross section adhered to copper foil as etching resist

14 copper foil cross section forming circuit

21 Direction of laser irradiation

22 irradiated laser

23 Reflected Laser

24 Laser through base plate of laser mask

25 base plate of laser mask

26 Coating of laser mask

27 Copper foil removed by laser

28 blower cross section

29 compressed air

The circuit formation method of the circuit board by the laser and the laser mask of the present invention is a base plate of the total reflection mirror used in the laser amplification process or a material used for the laser lens (Fused Silica, BK7, etc.) And reflecting materials (dieletrics; Oxides, Fluorides, Sulfides, etc., metals; Au, Ag, Al, Ni-Cr, etc., semiconductors; Si, Ge) coated on the total reflection mirror used in the laser amplification process on one side of the base plate After coating, the coating part is etched so that only the coating part of the circuit pattern remains, forming a laser pattern coating part, and the laser mask having the circuit pattern coating part is kept parallel to the copper foil surface by maintaining a predetermined interval on the copper foil surface bonded to the substrate. The blower compresses the removed copper foil while removing the copper foil by irradiating a laser in the direction of the copper foil adhered to the substrate from the laser mask. A group composed of a circuit forming step in the circuit board blowing.

In order to form the circuit of the circuit board by applying the present invention, a laser and a laser mask are required. The laser that can be employed in the present invention can be either a laser of an infrared ray system that melts the copper foil with the accompanying high heat, or a laser of an ultraviolet ray laser that removes the copper foil without high heat. The laser needs to be selected in consideration of only the laser wavelength and the range of pulse energy necessary for the purpose.

The laser mask is made of the base plate of the total reflection mirror used in the laser amplification process or the material of the laser lens (Fused Silica, BK7, etc.) to make a thin and constant double-sided base plate and to coat one side of the base plate on the total reflection mirror used in the laser amplification process. After coating with the laser reflection material (dieletrics; Oxides, Fluorides, Sulfides, metal; Au, Ag, Al, Ni-Cr, semiconductors; Si, Ge), the coating is etched to leave only the circuit pattern part . In etching the coating part of the laser mask, first, a method of forming a circuit pattern coating part by etching the coating part of the base plate using a high-power laser, and secondly, using a circuit forming method of a conventional PCB manufacturing method, that is, drying the coating part of the base plate. The film is adhered closely, the exposure film is placed thereon, and the UV film is irradiated to selectively dry the portion of the dry film to form a circuit pattern, and then the developer is used to melt the uncured dry film and the exposed coating using the corrosion solution. There is a method of forming a circuit pattern coating part by corroding the part so that only the coating part of the circuit pattern remains and peeling the photocured dry film, which has completed the role as an etching resist, with a peeling solution.

The base plate and the coating material of the laser mask are selected from those of the base plate and the coating material employed in the total reflection mirror used in the laser amplification process, each having an excellent damage threshold, and the material and thickness of the base plate and the coating are determined according to the laser to be used. Decide to have

2 and 2 illustrate a circuit forming method of a circuit board according to the present invention. The circuit formation principle of the circuit board according to the present invention is as follows. Placing the laser mask with the circuit pattern coating on the surface of the copper foil attached to the substrate in parallel with the surface of the copper foil, and irradiating the laser in the direction of the copper foil from the laser mask, the laser is reflected from the circuit pattern coating and the coating is removed. In the laser transmission, the laser reaches the surface of the copper foil, and since the laser reaching the surface of the copper foil removes the copper foil, only the circuit portion of the copper foil attached to the substrate remains. At this time, in order to prevent the laser mask from being contaminated by the copper foil removed by the laser and to facilitate processing, compressed air is simultaneously sprayed on both the laser mask and the copper foil with a blower installed between the laser mask and the surface of the copper foil.

For circuit formation of a complete circuit board, first select the direction (horizontal direction or vertical direction) to be processed, and irradiate the laser along a straight line in the selected direction to remove the copper foil parts other than the circuit pattern, and immediately after finishing the selected direction The processed portion and the laser overlap so that the laser is irradiated to proceed. If the diameter of the laser is larger than the smaller one of the specifications (horizontal and vertical) of the circuit board, the laser can be processed only once in the direction of the larger specification to form a circuit of a complete circuit board. Therefore, it is preferable to use a laser having a large diameter as much as possible.

The present invention reduces the defective products caused by the adoption of the circuit formation method of the conventional PCB manufacturing method by using a laser and a laser mask in the circuit formation of the circuit board, and solves the environmental problems caused by the use of chemicals as well as process shortening This improves productivity and reduces costs.

Claims (2)

In forming a circuit of a single layer or multilayer circuit board, a laser transmitting material (Fused Silica, BK7, etc.) is used as a base plate, and a laser reflecting material (dieletrics; Oxides, Fluorides, Sulfides, etc., metal; Au, Ag, Al, etc.) is formed on one side of the base plate. Laser mask formed by forming circuit pattern coating with semiconductors (Si, Ge, etc.), Ni-Cr, etc., at a constant distance on the copper foil surface, parallel to the copper foil surface, and irradiating the laser and blowing the copper foil removed by the laser Circuit formation method for forming a circuit on the surface of copper foil attached to a substrate by blowing off the compressed air The base plate material (Fused Silica, BK7, etc.) of the total reflection mirror used in the laser amplification process is made of a thin and uniform double-sided base plate of the total reflection mirror used in the laser amplification process on one side of the base plate Laser masks that form circuit pattern coatings with materials (dieletrics; Oxides, Fluorides, Sulfides, etc., metals; Au, Ag, Al, Ni-Cr, etc., semiconductors; Si, Ge)