JPH09246693A - Circuit board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently manufacturing a circuit board having a circuit pattern which is partially different with respect to at least one of their width, thickness and sectional shape, without deteriorating their good electrical characteristics. SOLUTION: First, an alumina substrate 12 is prepared. When the alumina substrate 12 is subjected to a laser processing operation with use of a laser beam 11 to form grooves 13 therein, beam processing conditions are varied even in the course of the processing operation to form grooves 13 which are partially different in at least one of their width, depth and sectional shape. Thereafter conductive paste 14 is filled into the grooves 13. As a result, there can be formed a circuit pattern 16 which is partially different in at least one of its width, thickness and sectional shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board manufacturing method and a circuit board, and more particularly, to a circuit board having at least one of the width, thickness, or cross-sectional shape of a circuit pattern partially different. The present invention relates to a manufacturing method and a circuit board.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a circuit board such as a hybrid IC board, a circuit pattern is formed on the surface of a board such as an alumina board by screen printing.

A conventional method for manufacturing a circuit board and a circuit board will be described below with reference to the drawings.

FIG. 3 is a side view showing a conventional method for manufacturing a circuit board by screen printing. FIG. 4 is a partially enlarged view showing a mask used for screen printing,
4A is a plan view and FIG. 4B is a plan view.
It is sectional drawing in the YY line of (a).

As shown in FIG. 3, first, the mask 2 is arranged on the substrate 1 positioned on the base plate d with an appropriate gap g. As shown in FIG. 4, the mask 2 includes an emulsion 3 having an opening 3a formed therein, and a mesh 4 mounted on the emulsion 3 and having a wire-like mesh structure.

Then, the paste-like conductive material 5 is applied onto the mask 2, and the squeegee 6 is moved in the horizontal direction while being pressed against the substrate 1 from above the mask 2.
The portion of the mask 2 that has been pressed by is in contact with the surface of the substrate 1, and the conductive material 5 passes through the opening 3 a formed in the emulsion 3 and adheres to the surface of the substrate 1.

At this time, the portion of the mask 2 pressed by the squeegee 6 once contacts the surface of the substrate 1 due to the bending of the mask 2, but when the squeegee 6 passes, it floats due to the tension of the mask 2 and the substrate The printing of the conductive material 5 on the surface of 1 is completed.

After that, the conductive material 5 printed on the surface of the substrate 1 is dried and baked to complete a circuit board on which a circuit pattern is formed.

[0009]

With the recent miniaturization of electronic components and high-density integration on circuit boards, the circuit patterns on the circuit boards also tend to be miniaturized.

When the width dimension of the circuit pattern to be formed on the substrate is relatively large (for example, 100 μm or more), it can be dealt with by the screen printing as described above, but the width dimension is fine (for example, 75 μm or less). If a circuit board having the circuit pattern of No. 1 is to be obtained by screen printing as described above, there are the following problems.

First, as shown in FIG. 3, when the squeegee 6 is pressed from above the mask 2 toward the substrate 1, a gap c is formed between the emulsion 3 and the substrate as shown in FIG. When the conductive material 5 enters the gap c, as shown in FIG. 6, a bleed 8 occurs on the circuit pattern 7 printed on the substrate 1 and causes a short circuit due to contact with the adjacent circuit pattern 7a. became.

Second, as shown in FIG. 3, after the squeegee 6 is moved horizontally on the mask 2, the mask 2 is removed.
When the conductive material 5 is pulled by the emulsion 3 when it floats due to its tension, as shown in FIG. 7, the circuit pattern 7 printed on the insulating substrate 1 has a stringed corner 9 and is adjacent to the circuit pattern 7. This caused a short circuit due to the contact with the circuit pattern 7a.

Third, as shown in FIG. 3, when the conductive material 5 is applied on the mask 2, if the applied amount is insufficient,
As shown in FIG. 8, blurring 10 occurs and the circuit pattern 7
Was the cause of the disconnection.

When a circuit board having a circuit pattern having a fine width dimension and a circuit pattern having a relatively large film thickness is formed on the same insulating substrate by screen printing as described above, There were the following problems.

For example, since a portion of the circuit pattern on which the electronic component is mounted needs adhesive strength, a relatively large film thickness (for example, 30 μm or more) is required, but a width dimension is fine (for example, 75 μm or less). Since the circuit pattern of (1) must be printed using a mask having a thin emulsion, the film thickness becomes small (about 10 μm).

Therefore, it has been impossible to print a circuit pattern having a relatively large film thickness using a mask for a circuit pattern having a fine width dimension.

Therefore, in order to obtain a circuit board having a circuit pattern having a fine width dimension and a circuit pattern having a relatively large film thickness on the same insulating substrate by the screen printing as described above, There is a problem that it is necessary to prepare a plurality of masks having different emulsion thicknesses, and there is a problem that the number of times of printing increases depending on the number of masks required.

Therefore, an object of the present invention is to provide a circuit board in which at least one of the width, thickness, or sectional shape of a circuit pattern is partially different, without impairing good electrical characteristics. An object of the present invention is to provide a method of manufacturing a circuit board that can be manufactured efficiently.

Another object of the present invention is to provide a circuit board which has no short circuit or disconnection, has good electrical characteristics, and can be manufactured efficiently.

[0020]

According to the method of manufacturing a circuit board of the present invention, when a board is prepared and a groove is formed on the main plane of the board by beam processing, the processing conditions of the beam processing are changed during processing. And forming a groove in which at least one of width, depth, or cross-sectional shape is partially different, and filling the groove with a conductive material, and at least one of width, thickness, or cross-sectional shape is And a step of forming partially different circuit patterns.

The beam processing mentioned here is, for example, processing using a laser beam or an electron beam.

Further, the processing conditions of the beam processing here include, for example, wavelength, oscillation conditions, beam profile,
The scanning speed of the beam, the number of times of scanning, and the like.

According to the method of manufacturing a circuit board of the present invention, a circuit pattern is formed by beam processing without using a mask for screen printing. It is possible to reliably form without forming abnormalities such as corners and blurring.

Further, according to the method for manufacturing a circuit board of the present invention, when forming a groove on the main plane of the board by beam processing, the processing conditions of the beam processing are changed during processing, so that the width, depth, Alternatively, a groove in which at least one of the cross-sectional shapes is partially different can be formed, and by filling the groove with a conductive material, at least one of the width, the thickness, or the cross-sectional shape is partially formed. Different circuit patterns can be formed on each.

Further, the circuit board of the present invention comprises a board and a circuit pattern formed on the main plane of the board, and the circuit pattern is made of a conductive material filled in a groove provided in the board. At least one of the width, thickness, or cross-sectional shape of the circuit pattern is partially different.

Such a circuit board can be manufactured by using the above manufacturing method.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a circuit board manufacturing method and a circuit board according to the present invention will be described below with reference to the accompanying drawings.

First, a method of manufacturing the circuit board of the present invention will be described.

FIG. 1 is a process diagram for explaining a method of manufacturing a circuit board which is an embodiment of the present invention.

First, in the groove forming step shown in FIG. 1A, a laser oscillator (not shown) for irradiating the Qsw YAG laser beam 11 and an alumina substrate 12 which is a rectangular flat plate-shaped substrate are prepared. Next, when the laser beam 11 emitted from the laser oscillator is condensed by the condenser lens 14, the alumina substrate 12 is arranged at a position which becomes a focal point, and the condenser lens 1
The laser light 11 condensed in 4 and the alumina substrate 12 are moved relatively.

That is, the laser beam 11 may be moved using a scanning optical system (not shown), or the alumina substrate 12 may be moved using an XY table (not shown). Thereby, the groove 13 having a minimum width of 20 μm can be formed on the alumina substrate 12. Qsw Y
Since the AG laser beam 11 is a single mode with good condensing property, the width dimension of the groove 13 formed in the alumina substrate 12 can be reduced.

By increasing the number of times the laser beam 11 is scanned, the groove 13 having a width dimension of 20 μm or more can be formed.

Further, the groove 13 formed in the alumina substrate 12
The scanning speed of the laser beam 11 may be adjusted in order to adjust the depth. That is, if the scanning speed of the laser light 11 is increased, the groove 13 becomes shallower, and if the scanning speed of the laser light 11 is decreased, the groove 13 becomes deeper.

Further, the groove 13 formed in the alumina substrate 12
The beam profile of the laser beam 11 may be adjusted to adjust the cross-sectional shape of the laser beam. For example, to make the cross-sectional shape of the groove 13 rectangular, the beam profile may be rectangular. Further, the cross-sectional shape of the groove 13 can be V-shaped or U-shaped.

Further, the groove 13 formed in the alumina substrate 12
The cross-sectional area of can be freely set by combining the width, depth, and adjustment of the cross-sectional shape of the groove 13.

Therefore, the width, depth, cross-sectional shape, and cross-sectional area of the groove 13 formed in the alumina substrate 12 are determined by the laser light 11
Can be freely controlled by changing the processing conditions such as the wavelength, scanning frequency, scanning speed, and beam profile.

Next, in a paste filling step shown in FIG. 1B, a conductive paste 14 which is a conductive material is applied to the surface of the alumina substrate 12.

Next, the squeegee 15 is moved horizontally from above the alumina substrate 12 coated with the conductive paste 14 while applying pressure. As a result, the conductive paste 14 is filled in the groove 13 formed in the groove forming step. At this time, since no mask is interposed between the alumina substrate 12 and the squeegee 15, compared with the case of screen printing,
The filling property of the conductive paste 14 is good.

Finally, in the baking step shown in FIG. 1C, the alumina substrate 12 having the conductive paste 14 filled in the grooves 13 is heat-treated, and the conductive paste 14 is dried and baked to form a circuit pattern. The completed circuit board is completed.

Next, the circuit board of the present invention will be described.

2A and 2B are views showing a circuit board obtained by the above-described method for manufacturing a circuit board, FIG. 2A is a perspective view, and FIG. 2B is an X of FIG. 2A. It is a sectional view taken along the line X-.

This circuit board is composed of an alumina substrate 12 which is a rectangular flat board and a circuit pattern 16 formed on the surface of the alumina substrate 12.

The circuit pattern 16 is, as shown in FIG.
Since the conductive paste 14 filled in the grooves 13 formed on the surface of the alumina substrate 12 is formed by baking, the alumina substrate 12 is, as shown in FIG.
In contact with the bottom and sides of the groove 13 and thus
High adhesive strength.

Further, since the circuit pattern 16 is formed by baking the conductive paste 14 filled in the groove 13 formed on the surface of the alumina substrate 12 as shown in FIG. 1, as shown in FIG. 2b. The width of the circuit pattern 16,
The thickness, sectional shape, and sectional area correspond to the width, depth, sectional shape, and sectional area of the groove 13 formed in the alumina substrate 12, respectively.

The circuit pattern 16 is the pattern A,
It consists of pattern B and pattern C.

The pattern A is a land on which electronic parts are mounted, and requires a large surface area and adhesive strength. Therefore, the width dimension is large and the thickness is large. The cross-sectional shape is rectangular.

The pattern B is a line in which a small amount of current flows, and a fine width is required, but adhesive strength is not required.
Therefore, the width dimension is small and the thickness is small. The cross-sectional shape is rectangular.

The pattern C is a line in which a large amount of current flows, and a wide cross-sectional area is required, but adhesive strength is not required. Therefore, the width dimension is large and the thickness is small. The cross-sectional shape is rectangular.

As described above, the circuit board manufacturing method and the circuit board of the present invention have been described based on one embodiment, but the present invention is not limited to the above embodiment.
Various modifications can be made within the scope of the present invention.

For example, in the above embodiment, the groove 13 was formed directly on the surface of the alumina substrate 12, but the present invention is not limited to this. For example, the surface of the alumina substrate 12 is covered with a photosensitive resin or the like. After forming the cover film, the groove 13 may be formed on the surface of the alumina substrate 12 by beam processing from above the cover film.

In this case, the conductive paste 14 is filled in the groove 13 of the alumina substrate 12, but does not adhere to the surface of the alumina substrate 12 where the groove 13 is not formed. In addition, since the coating film disappears when the alumina substrate 12 is baked, the conductive paste 14 that slightly adheres to the surface of the coating film may adhere to the surface of the alumina substrate 12 where the groove 13 is not formed. There is no.

Therefore, in this case, a circuit component having good electric characteristics can be easily obtained.

In the above embodiment, the alumina substrate 12 is pre-baked before the conductive paste 14 is baked, but the present invention is not limited to this. For example, the baking temperature is low. By using a substrate made of a material, the substrate can be fired and the conductive paste 14 can be fired at the same time.

In the above embodiment, the laser oscillator for irradiating the Qsw YAG laser beam 11 is used in the groove forming step by beam processing, but the present invention is not limited to this, and for example, an excimer laser, YAG
Alumina substrate 12 such as SHG (second harmonic) of laser
A laser oscillator that has a high absorption rate and irradiates the laser light 11 having a short wavelength may be used. In this case, the width dimension of the groove formed on the alumina substrate 12 can be further reduced, and can be 20 μm or less.

In addition, it goes without saying that the shapes and materials of the insulating substrate and the circuit pattern can be changed.

[0056]

As described above, according to the method for manufacturing a circuit board of the present invention, the circuit pattern is formed by beam processing without using a mask for screen printing, so that the circuit pattern having a fine width dimension is used. Even bleeding,
It is possible to surely form without forming abnormalities such as blurring.

Therefore, according to the method of manufacturing a circuit board of the present invention, it is possible to provide a circuit board having good electrical characteristics without a short circuit or disconnection.

Further, according to the method of manufacturing a circuit board of the present invention, when forming a groove on the main plane of the board by beam processing, the processing conditions of the beam processing are changed during processing, so that the width, depth, Alternatively, a groove in which at least one of the cross-sectional shapes is partially different can be formed, and by filling the groove with a conductive material, at least one of the width, the thickness, or the cross-sectional shape is partially formed. Different circuit patterns can be formed on each.

Therefore, according to the method of manufacturing a circuit board of the present invention, a circuit board having a circuit pattern having a fine width dimension and a circuit pattern having a relatively large film thickness is formed on the same insulating substrate. However, it can be efficiently manufactured in a short time.

The circuit board of the present invention can be manufactured using the above manufacturing method.

Therefore, with the circuit board of the present invention,
The same effect as that obtained by the above manufacturing method can be obtained.

[Brief description of drawings]

FIG. 1 is a process diagram illustrating a method for manufacturing a circuit board that is an embodiment of the present invention.

2A and 2B show a circuit board according to an embodiment of the present invention, FIG. 2A being a perspective view and FIG.
It is sectional drawing in the XX line of (a).

FIG. 3 is a cross-sectional view showing a method for manufacturing a circuit board using conventional screen printing.

FIG. 4 is a partially enlarged view showing a screen printing mask used in a conventional circuit board manufacturing method.
4A is a partially enlarged plan view, and FIG.
It is a partial expanded sectional view in the YY line of (a).

FIG. 5 is a cross-sectional view showing a method of manufacturing a circuit board using conventional screen printing.

FIG. 6 is a partially enlarged plan view showing a circuit board obtained by a conventional circuit board manufacturing method using screen printing.

FIG. 7 is a partial enlarged cross-sectional view showing a circuit board obtained by a conventional method of manufacturing a circuit board using screen printing.

FIG. 8 is a partially enlarged plan view showing a circuit board obtained by a conventional method for manufacturing a circuit board using screen printing.

[Explanation of symbols]

 11 Laser Light (Beam) 12 Alumina Substrate (Substrate) 13 Groove 14 Conductive Paste (Conductive Material) 16 Circuit Pattern

Claims (2)

[Claims] 1. When a substrate is prepared and a groove is formed on the main plane of the substrate by beam processing, the processing conditions of the beam processing are changed during the processing, and at least the width, the depth, or the cross-sectional shape is changed. A step of forming a partially different groove, and a step of filling the groove with a conductive material to form a circuit pattern in which at least one of width, thickness, or sectional shape is partially different. And a method for manufacturing a circuit board. 2. A substrate, and a circuit pattern formed on a main plane of the substrate, wherein the circuit pattern is made of a conductive material filled in a groove provided in the substrate, and a width of the circuit pattern, thickness,
Alternatively, at least one of the cross-sectional shapes is partially different, which is a circuit board.