KR20000019910A - Method for forming printed circuit board - Google Patents

Abstract

PURPOSE: A method for forming a printed circuit board is provided to form a hole at an exact location by irradiating a laser beam moving a laser into a hole forming location on the basis of a recognized aligning mark. CONSTITUTION: A circuit and aligning mark is formed by etching a copper foil of a copper foil pile plate. A circuit(22) is formed by attaching a resin, on which a copper foil is piled, on the copper foil pile plate and by etching the copper foil. After exposing the aligning mark(29) to the exterior etching the copper foil pile plate on the aligning mark by a laser(30), a location of the aligning mark is recognized. The laser is shifted into a hole forming location on the basis of the recognized aligning mark. After forming a hole(24) at the hole forming location irradiating the laser beam, a metal is coated inside the hole.

Description

Printed Circuit Board Manufacturing Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board. In particular, an alliance mark may be formed on a substrate to improve reliability by forming a conductive hole connecting the circuits at a precise place in the manufacture of the multilayer printed circuit board. A method for manufacturing a multilayer printed circuit board.

In recent years, according to the thin and short size of electronic products, printed circuit boards on which electronic components are mounted are also composed of multilayers, and multilayer printed circuit boards capable of realizing high density have been actively studied. The multilayer printed circuit board is formed by etching a single-sided or double-sided copper-clad laminate to form a circuit, and then heating and pressing the substrate to compress the circuits. The circuits formed on the substrate are connected to each other through a via hole or a through hole. .

Such a multilayer printed circuit board is shown in FIG. In this multilayer printed circuit board, as shown in FIG. 1 (a), both surfaces of copper clad laminates (Copper Clad Laminate; 1a and 1b) coated with copper foil on both sides are etched by general photolithography to form a circuit (2). The resin 3a is applied to the CCLs 1a and 1b, and then pressurized and heated to bond two CCLs 1a and 1b on which the circuit 2 is formed. Resin-coated copper foil is deposited on the upper and lower surfaces of the two bonded CCLs 1a and 1b, and then heated and pressed to bond the copper foils on the resins 3b and 3c. To form the circuit 2. Subsequently, a via hole 4 and a through hole 5 are formed in a predetermined position of the substrate, and a metal layer 6 is formed inside the via hole 4 and the through hole 5 to connect the circuits, and at the same time, a multilayer printed circuit. Connect the components mounted on the board.

In the above manufacturing method, the method of forming the via hole 4 and the through hole 5 in the substrate can be classified into two types. One is a method of forming the holes 4, 5 by chemical etching, and the other is a method of forming the holes 4, 5 by laser processing.

In the method of forming the holes 4 and 5 by laser processing, an excimer laser or a yag laser is used as the laser. In case of using excimer laser, there is a problem in selecting material of insulating layer of CCL (1a, 1b), and there is a problem that the degree of freedom of processing up to a certain depth decreases during processing, so that the density of substrate decreases. It is preferable.

However, in the case of forming the holes 4 and 5 by using the laser as described above, unlike the chemical etching method of forming holes using a mask, it is desirable to accurately set the hole forming position of the printed circuit board. This is an important issue for improving accuracy. That is, when the hole is formed by the laser processing apparatus, the machining position must be programmed in the apparatus to move the laser to the machining position, and then the laser processing starts. However, there is no reference point for moving the laser to the programmed machining position on the substrate. This makes it impossible to machine the hole at the correct machining position.

In the laser processing apparatus, a two-dimensional coordinate axis in which the laser is moved is set, and the movement of the laser moves along the coordinate. The reference point of the coordinate is set to (0,0) on the two-dimensional x, y plane. To form a hole at the correct machining position on the substrate, the reference point of the substrate (eg the edge of the substrate) and the reference point of the coordinates must always coincide when the substrate is set in the processing apparatus. However, since there is always a mechanical error or an error occurring when setting the substrate to be processed on the actual manufacturing line, setting of the substrate as described above becomes impossible. Therefore, it is very difficult to place the laser in the correct processing place, and as a result, there is a problem that a defect occurs in the multilayer printed circuit board.

Fig. 1 (b) shows a multilayer printed circuit board in the case where holes 4 and 5 are formed at poor positions. Since the holes 4 and 5 are not formed at the correct positions as designed, the connections between the circuits 2a and 2b, 2c and 2d are not made as shown in the drawing, which causes defects in the multilayer printed circuit board. There was a problem.

The present invention is to solve the above problems, by forming an alignment mark on a printed circuit board to recognize the position of the alignment mark and to move the laser to the hole forming position based on the recognized alignment mark position. It is an object of the present invention to provide a method for manufacturing a printed circuit board capable of always forming holes at an accurate position by irradiating laser bales to form holes.

In order to achieve the above object, a method of manufacturing a printed circuit board according to the present invention may include forming a circuit and at least one alignment mark by etching at least one single-sided or double-sided copper-clad laminate, and coating copper foil on the copper-clad laminate. Bonding the resin and etching the copper foil to form a circuit again; etching the bonded copper-clad laminate with a laser to expose the alignment marks to the outside and recognizing the position of the alignment marks; Moving the laser to a hole forming position using an inning mark as a reference point, forming a hole at the hole forming position by irradiating a laser beam, and plating a metal inside the hole.

The aligning mark is composed of a plurality of marks having different shapes and sizes, and is formed at four corners of the copper clad laminate. In addition, a plurality of courses are formed in the copper-clad laminate, so that the substrate is accurately set in the laser equipment.

Figure 1 (a) is a cross-sectional view showing a typical multilayer printed circuit board.

1B is a cross-sectional view of a multilayer printed circuit board having holes formed in incorrect positions.

2 is a view showing a method of manufacturing a printed circuit board according to the first embodiment of the present invention.

3 is a plan view of a substrate on which an alignment mark is formed.

4 is a view showing a method of manufacturing a printed circuit board according to a second embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

21,51: CCL 23,53: RCC

22,52: circuit 29,59: alignment mark

30,60 Laser 24,54,55 Hole

Hereinafter, a method of manufacturing a printed circuit board according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing a printed circuit board manufacturing method according to a first embodiment of the present invention. As shown in Fig. 2A, first, the copper foil of the end face CCL 21 is etched to form the circuit 22 and the aligning mark 29, and then the RCC 23 is deposited on the upper surface of the CCL 21. After heating, pressing, and bonding, the copper foil on the resin is further etched to form the circuit 2.

Although only two aligning marks 29a and 29b are formed on both sides of the CCL 21 in the drawing, the actual aligning marks are formed at the four corners of the CCL 21 as shown in Fig. 3 (a). do. Aligning marks 29a, 29b, 29c, and 29d are formed by a chemical etching method similarly to the circuit.

Each of the aligning marks 29a, 29b, 29c, and 29d is composed of four marks, and each mark has a different shape from each other. The reason why the aligning marks 29a, 29b, 29c, and 29d are composed of four marks of different shapes is to use another mark when the mark is damaged by etching or other defects. Of course, instead of using the alignment marks 29a, 29b, 29c, and 29d of four marks as described above, it is also possible to use the alignment marks 29a, 29b, 29c, and 29d of two or more marks. In addition, the reason why the size of the four marks are different is to enable the use of various laser equipment. That is, since the size of the mark can be recognized according to the equipment, when a plurality of different marks are formed as described above, holes are formed using various laser equipment (for example, yag laser, excimer laser, CO2 laser, etc.). Can be formed.

Further, the first mark of each alignment mark 29a, 29b, 29c, 29d is about 10 mm away from the edge of the CCL 21, the second mark is about 14 mm, and the third mark is about 24 mm away, and the fourth mark is Is about 34mm away. That is, each of the alignment marks 29a, 29b, 29c, and 29d are all formed within about 34 mm from the edge of the CCL 21.

Fig. 3B is a view showing the shape of each alignment mark 29a, 29b, 29c, 29d. As shown in the figure, the alignment marks 29a, 29b, 29c, and 29d are composed of four marks. The first mark is a rectangular shape having a diagonal length of about 300 μm, the second mark is a circular shape having a diameter of about 500 μm, and the third mark is a circular shape having a diameter of about 300 μm. Further, the fourth mark has a cross shape having a width of about 850 µm.

As described above, although marks of specific shapes and sizes are shown in the figures, these shapes and sizes do not limit the present invention. Any shape and size other than the specific shape and size shown in the drawings are applicable if each mark consists of different shapes and sizes.

Subsequently, as shown in FIG. 2 (b), the laser operates a factory value to move the laser 30 to the point where the first aligning mark 29 is formed, and then a laser beam of minute intensity is applied to the RCC 23. Investigate. Although the laser 30 can also be an excimer laser, it is preferable to use a yag laser for workability. By the irradiation of the laser beam, the RCC 23 is etched to expose the first alignment marks 29a to the outside. At this time, only the RCC 23 is etched and the first aligning mark 29a is irradiated with an intensity that is not processed.

When the aligning mark 29a is exposed to the outside as described above, the third mark of the four marks shown in FIG. 3 (b) is exposed to the outside. However, the exposure of this particular mark is not particularly meaningful. Therefore, it is also possible to expose other marks other than the third mark, and in particular, when a particular mark is damaged, it is possible to achieve the object of the present invention by exposing other marks except the damaged mark.

Although not shown in the figure, a sensor is attached to the laser 30. Therefore, when the laser beam is irradiated to the exposed first alignment mark 29a, the laser beam is reflected by the first alignment mark 29a, and the sensor detects the reflected beam and the first alignment mark 29a. ) And recognize its presence and set its position.

Subsequently, as shown in Fig. 2C, the laser 30 is moved to the second alignment mark 29b and the laser beam is irradiated to the RCC 22 again. By irradiation of the laser beam, the RCC 22 on the second aligning mark 29b is etched to expose the second aligning mark 29b to the outside. At this time, similarly to the first alignment mark 29a, the third mark of the four marks is exposed to the outside. The laser beam reflected from the exposed alignment mark 29b is input again by the sensor of the laser to sense the position of the alignment mark 29b. The process continues to the third aligning mark 29c and the fourth aligning mark 29d shown in Fig. 3A, so that the positions of the four aligning marks 29a, 29b, 29c, and 29d are It is recognized.

Recognized alignment marks 29a, 29b, 29c, and 29d provide reference points for hole formation. That is, when the formation position of a specific hole is displayed as coordinates, the coordinates are displayed as coordinates based on the alignment marks 29a, 29b, 29c, and 29d, not the movement coordinates of the apparatus set in the laser processing apparatus itself. .

In the laser processing apparatus, the new coordinates of the apparatus are set by calculating the positions of the four alignment marks 29a, 29b, 29c, and 29d that are recognized and the total correction value. Then, as shown in Fig. 2 (d), the laser is moved to the programmed position based on the new coordinate axis and irradiated with the laser beam. At this time, the laser beam is irradiated with an intensity much stronger than that of the laser beam irradiated to expose the alignment marks 29a, 29b, 29c, and 29d so that the circuit 22 and the RCC 23 formed on the RCC 23 are exposed. ) Is formed to form the via hole 24. In addition, the through hole may be formed in the substrate by increasing the intensity of the laser beam. Subsequently, although not shown in the drawing, the via hole 24 is plated with metal to electrically connect the circuit of the CCL 21 and the circuit of the RCC 23.

As shown in Fig. 3A, a plurality of courses 31a, 31b, and 31c are formed in the LCC 21. The courses 31a, 31b and 31c have a hole shape and recognize a state in which a substrate is set in the laser processing apparatus during hole processing. That is, when the substrate is set in the laser processing apparatus, it is checked whether the upper and lower surfaces of the substrate are set in the changed state or the lower part of the substrate is set in the state of being rotated upward so that the substrate is always set in the correct state. Therefore, the above process is performed before the laser processing so that the laser processing is always successful.

As described above, in the method of manufacturing the printed circuit board according to the first embodiment of the present invention, since the hole machining positions are recognized using the alignment marks 29a, 29b, 29c, and 29d, holes can be always formed at the correct positions. do.

4 relates to a method of manufacturing a printed circuit board according to a second embodiment of the present invention. Unlike the first embodiment, the present embodiment relates to a method of manufacturing a multilayer printed circuit board.

First, as shown in Fig. 4 (a), the copper foils of the first or second CLL 51a and the second CLL 51b are etched to form the circuit 52 and the alignment marks 59a, 59b, 61a, and 61b. Thereafter, the first CLL 51a and the second CLL 51b are bonded to each other by heating and pressurizing the resin 53a therebetween. Subsequently, the upper and lower surfaces of the first CLL 51a and the second CLL 51b are heated, pressurized and bonded to the upper and lower surfaces of the first CLL 51a and the second CLL 51b, and the copper foil is etched to etch the first and second RCCs 52b and 52c. ) Form a circuit over it.

Subsequently, although not shown in the figure, the substrate is accurately set in the laser processing apparatus by a plurality of courses formed in the substrate.

Subsequently, the first LCC 51a is irradiated with the laser beam of weak intensity to the first LCC 51a so that the first LCC 51a is etched, thereby aligning the alignment marks 59a and 59b. Expose to the outside. Although only two alignment marks are shown in the figure, in the actual manufacturing process, the alignment marks formed on the four corners of the substrate are exposed to the outside.

Then, as shown in Fig. 4B, the laser beam is irradiated onto the second LCC 51b so that the second LCC 51b is etched to expose the alignment marks 61a and 61b to the outside.

When exposing the aligning marks 59a, 59b, 61a, and 61b formed on the first CCL 51a and the second CCL 51b to the outside, a specific mark of four marks is exposed as in the first embodiment.

As the laser beams are reflected on the alignment marks 59a and 59b of the first LCC 51a and the alignment marks 61a and 61b of the second LCC 51b exposed to the outside, the laser beam is reflected and sensed by a sensor mounted on the laser. The positions of the alignment marks 59a, 59b, 61a, 61b are recognized. The positions of the recognized alignment marks 59a, 59b, 61a, 61b are calculated by the laser processing apparatus to correct the whole value to give the processing apparatus new coordinate values.

Thereafter, as shown in Fig. 4C, the laser is moved to the programmed movable position and the laser beam is irradiated to form the via hole 54 and the through hole 55. At this time, since the intensity of the irradiated laser beam is much larger than the intensity of the irradiated laser beam to expose the alignment marks 59a, 59b, 61a, and 61b, the LCCs 51a, 51b and RCC 53a, 53b, 53c. ) Are all penetrated. Subsequently, the via hole 54 and the through hole 55 are plated with metal to connect the interlayer circuits to each other.

In the above method, the alignment marks are formed not only on the upper surface of the substrate but also on the lower surface. Therefore, since the hole formation position is calculated not only on the upper surface but also on the lower surface of the substrate, when the upper and lower surfaces are not disposed correctly when the multilayer substrate is bonded, that is, when the circuits that must be connected to each other are shifted between the layers, the holes are connected to the circuit. It is possible to form in the form. Therefore, the interlayer circuit can be connected well regardless of the direction in which the holes are formed.

Similarly to the first embodiment, the second embodiment uses an alignment mark made of four marks, and the shape and size of each mark are formed differently so that the hole is formed even when the mark is damaged or other laser equipment is used. There is no problem.

As described above, in the method of manufacturing a printed circuit board according to the present invention, when the hole is formed using a laser, the hole forming position can be accurately determined by the aligning mark, so that the hole can be always formed at the correct position. Therefore, not only the defects in the printed circuit board can be prevented, but also the laser is automatically moved to the hole forming position, so that the manufacturing speed is further improved, thereby reducing the manufacturing cost. Further, since each aligning mark is composed of a plurality of marks having different shapes, it is possible to form a hole using another mark even when one mark is damaged. Furthermore, since a plurality of marks constituting one aligning mark are formed in different sizes, it is possible to use various kinds of laser equipment having different beam diameters.

Claims (10)

Etching the copper foil of the copper-clad laminate to form a circuit and at least one alignment mark; Bonding a resin in which copper foil is laminated on the copper foil laminated plate and etching the copper foil to form a circuit; Etching the copper clad laminate on the alignment mark with a laser to expose the alignment mark to the outside to recognize the position of the alignment mark; Moving the laser to a hole forming position by using the recognized alignment mark as a reference point; Irradiating a laser beam to form a hole in the hole forming position; And The method of manufacturing a printed circuit board comprising the step of plating a metal in the hole. The method of claim 1, wherein the alignment mark is formed at four corners of the copper-clad laminate. The method of claim 1, wherein the alignment mark is formed of a plurality of marks having different shapes. The method of claim 1, wherein the alignment mark is formed of a plurality of marks having different sizes. The method of claim 1, further comprising setting the substrate using a plurality of courses formed on the substrate before irradiating the laser beam. Etching the plurality of single-sided or double-sided copper-clad laminates to form a circuit and at least one alignment mark; Bonding the copper-clad laminate plate to the resin, bonding the resin coated with copper foil on the upper and lower surfaces of the copper-clad laminate plate, and etching the copper foil to form a circuit; Etching the upper surface of the laminated copper-clad laminate with a laser to expose the alignment marks to the outside to recognize the position of the alignment marks; Etching the lower surface of the laminated copper-clad laminate with a laser to expose the alignment marks to the outside and recognizing the position of the alignment marks; Moving the laser to a hole forming position by using the recognized alignment mark as a reference point; Irradiating a laser beam to form a hole in the hole forming position; And The method of manufacturing a printed circuit board comprising the step of plating a metal in the hole. The method of claim 6, wherein the alignment mark is formed at four corners of the copper-clad laminate. The method of claim 6, wherein the aligning mark is formed of a plurality of marks having different shapes. The method of claim 6, wherein the aligning mark comprises a plurality of marks having different sizes. The method of claim 6, further comprising setting the substrate using a plurality of courses formed on the substrate before irradiating the laser beam.