JPH11342491A - Desmear device for laser piercing equipment, and desmear method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desmear device for removing a residue component of a via hole by a wet process not depending on an immersion method in a desmear liquid tank. SOLUTION: This invention relates to a desmear device for removing a residue component left in a via hole formed on a resin layer above a metallic film of a work 17 by means of a laser piercing equipment. This desmear device comprises an applying part 1 for applying a desmear liquid on a surface of the resin layer, and a blow part 2 for removing the applied desmear liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser drilling apparatus for forming a via hole in a printed wiring board, particularly a multilayer printed wiring board using a laser beam. The present invention relates to a desmear apparatus and a desmear method for removing a residual residue component.

[0002]

2. Description of the Related Art In response to the demand for higher density of printed wiring boards in accordance with the miniaturization and high-density mounting of electronic devices, recently, multilayer printed wiring boards in which a plurality of printed wiring boards are stacked have appeared. In such a multilayer printed wiring board, it is necessary to electrically connect conductive layers (copper boards) between printed wiring boards stacked one above another. Such connection is made by a resin layer (polyimide,
This is realized by forming a hole called a via hole reaching the lower conductive layer in a polymer such as an epoxy resin) and plating the inside of the hole.

[0003] As a method of forming via holes, a mechanical fine drill was used before. However, with the reduction in the diameter of via holes accompanying the increase in density of printed wiring boards, recently, a laser drilling apparatus using laser light instead of a fine drill has been adopted.

[0004]

For example, a laser drilling apparatus for forming a via hole using a carbon dioxide gas laser or a YAG laser is well known, and has the advantage of being inexpensive and capable of high-speed processing. However, the via hole formed by such a laser drilling apparatus is thin on the bottom surface of the hole formed in the resin layer, that is, on a part or the entire surface of the conductive layer to be exposed (for polyimide or epoxy resin, There is a problem that a residual component (called smear) remains (thickness of 1 μm or less).

[0005] This residual component cannot be completely removed by further irradiating a laser beam thereafter. This is because even if the residual component is evaporated by further irradiating the laser beam, the surrounding resin elutes at this time (the conductive layer is often made of copper and the heat diffusion is fast), and the new residual component is removed. It is thought that it forms.

For this reason, conventionally, a wet process using a permanganate solution as a desmear solution after laser processing has been required to remove residual components.

However, the wet process is a method in which a printed circuit board after laser processing is immersed for a predetermined time in a liquid tank containing a desmear liquid, and a large installation space for the liquid tank and a large amount of I need. There is also a problem that the desmearing processing time becomes longer due to the time required for transfer from the laser drilling apparatus to the liquid tank.

Accordingly, an object of the present invention is to provide a desmear apparatus capable of removing residual components in via holes by a wet process that does not depend on a method of immersion in a desmear liquid tank.

Another object of the present invention is to provide a desmear method suitable for a laser drilling machine.

[0010]

According to the present invention, there is provided a laser drilling machine which irradiates a resin layer formed on a metal film on a work with a laser beam from a laser oscillator to form a residue remaining in a via hole formed on the metal film. A desmearing device for removing a component, comprising: an application unit for applying a desmear liquid to the surface of the resin layer; and a blow unit for removing the applied desmear liquid.

The work is a rectangular printed wiring board, and the coating means and the blowing means have a coating area and a blowing area, respectively, over the entire width of the printed wiring board in the width direction.

[0012] It is preferable that the coating means is one in which a plurality of desmear liquid blowing nozzles are arranged in a line over the entire length of the printed wiring board in the width direction.

Similarly, it is preferable that the blow means has a plurality of nozzles for blowing a plurality of gases arranged in a line over the entire length of the printed wiring board in the width direction.

[0014] Each of the coating means and the blowing means may include a drive mechanism movable in a direction perpendicular to a width direction of the printed wiring board.

A stage for mounting the printed wiring board and moving the printed wiring board in a uniaxial direction is provided. The coating means and the blow means are respectively provided in the width direction with respect to the printed wiring board mounted on the stage. The entire length of the printed wiring board is applied by applying the coating means and the entire surface of the printed wiring board is applied by the blowing means by moving the stage in the uniaxial direction. You may comprise so that a blow may be performed.

When the laser drilling apparatus has an XY stage for mounting the printed wiring board and moving the printed wiring board in the X-axis direction and the Y-axis direction, the desmear apparatus is incorporated into the laser drilling apparatus. Further, the coating means and the blowing means are arranged so that coating and blowing can be performed on the printed wiring board mounted on the XY stage over the entire length in the width direction, and a hole is formed in the work. After the end of the above-mentioned X-
By moving the Y stage in one of the X-axis direction and the Y-axis direction, application over the entire surface of the printed circuit board by the applying unit and blowing over the entire surface of the printed circuit board by the blowing unit are performed. You may comprise.

A desmear method for a laser drilling apparatus according to the present invention includes the steps of: irradiating a resin layer formed on a metal film in a work with a laser beam from a laser oscillator to form a via hole in the resin layer; In order to remove a residual component remaining in the via hole, an application step of applying a desmear liquid to the surface of the resin layer and a blowing step of removing the applied desmear liquid are performed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing a preferred embodiment of the present invention, a laser drilling apparatus suitable for applying a desmear apparatus according to the present invention will be described with reference to FIGS. In FIG. 2, a pulsed laser beam generated by a laser oscillator 10 using a CO ₂ (carbon dioxide gas) laser is guided to a mask 13 at a 90 ° angle by a reflection mirror 11. In the mask 13, the beam diameter of the laser beam is narrowed by passing through a hole that defines the via hole diameter, and the laser beam is guided to the XY scanner 14. X-
The Y scanner 14 is for oscillating a laser beam, and the oscillated laser beam acts as a focusing lens and passes through a processing lens 15 also called an fθ lens.
The work (printed wiring board) 17 placed on the Y stage 16 is irradiated. The XY stage 16 has a drive mechanism in the X-axis direction and a drive mechanism in the Y-axis direction.
7 can be moved on the XY plane to adjust the position.

In FIG. 3, the XY scanner 14
This is a so-called galvano scanner formed by combining two galvanometer mirrors 14-1 and 14-2. That is, the two reflection mirrors are independently rotated according to the driving principle of the galvanometer, so that the laser light is
5, it is possible to continuously irradiate a plurality of desired positions of the work 17.

In the case of a laser beam generated by a CO ₂ laser, a hole is formed by irradiating a pulsed laser beam per via hole several times (usually two to three times).
Usually, the scanning range of the XY scanner 14 is several c.
The area determined by this scanning range is set in the form of a matrix in the work 17 as a processing area, as will be described later. Then, the laser drilling device performs a plurality of drilling operations on the processing region, and when the drilling operation of a certain processing region is completed, moves to the next processing region and performs the drilling operation of the same pattern. The movement to the next processing area is usually performed by the XY stage 16.

The desmear apparatus according to the present invention is applied to the above-described laser drilling apparatus, but is not particularly limited by the type of laser oscillator.

An embodiment of the present invention will be described with reference to FIG. First, a laser drilling device and a separate type desmear device will be described. This desmear apparatus is for removing residual components remaining in the via holes of the work 17 formed by the laser drilling apparatus described with reference to FIG. 2, and the desmear liquid is applied to the surface of the work 17, that is, the surface of the resin layer. Coating unit 1 for applying a linear coating
And a blow unit 2 for linearly removing the applied desmear liquid
And a stage 3 on which the work 17 is mounted and moved in one axis direction indicated by an arrow in the figure.

Each of the application section 1 and the blow section 2 has an application area and a blow area over the entire width of the rectangular work 17 in the width direction. For this purpose, the coating unit 1 is configured by arranging a plurality of desmear liquid blowing nozzles 1-1 in a line over the entire length of the work 17 in the width direction. Similarly, the blow unit 2 is configured by arranging a plurality of nozzles 2-1 for blowing compressed air in a line over the entire length of the work 17 in the width direction. The gas blown from the blow unit 2 may be nitrogen gas. In particular, the application section 1
As for, what is called a curtain spray application system is commercially available.

As described above, the application section 1 and the blow section 2 are arranged so that the work 17 mounted on the stage 3 can be applied and blown over the entire length in the width direction, and the stage 3 is uniaxially mounted. By moving in the direction, application over the entire surface of the work 17 by the application unit 1 and blowing over the entire surface of the work 17 by the blow unit 2 become possible.

Actually, a predetermined time is required from the application of the desmear liquid to the removal thereof. For this reason, the desmear processing is performed by moving the drilled workpiece 17 to the stage 3.
The desmear liquid is applied to the surface of the work 17 by the application unit 1 while moving the stage 3 in one direction, and when the entire surface of the work 17 is completed, the stage 3 is moved in the opposite direction to return to the original position. return. After a predetermined time has elapsed, the desmear liquid remaining on the surface of the work 17 is blown off and removed by the compressed air from the blow unit 2 while moving the stage 3 in one direction.

The stage 3 is fixed, and the coating unit 1
Each of the blow units 2 may be moved by a drive mechanism that can move in a direction perpendicular to the width direction of the work 17.

Next, a case where the desmear apparatus according to the present invention is incorporated in a laser drilling apparatus as described with reference to FIG. 2 will be described. As described in FIG. 2, the laser drilling apparatus includes the XY stage 16 on which the work 17 is mounted and moved in the X-axis direction and the Y-axis direction. When incorporating into such a laser drilling machine,
For example, the application unit 1 is arranged on the left side of the processing lens 15 shown in FIG. 2, and the blow unit 2 is arranged on the right side of the processing lens 15 shown in FIG. Of course, the coating unit 1 and the blowing unit 2
-The work 17 mounted on the Y stage 16 is arranged such that application and blowing over the entire length in the width direction are possible.

By incorporating in this manner, the work 1
By moving the XY stage 16 in one of the X-axis direction and the Y-axis direction after the completion of the boring process on the workpiece 7, application over the entire surface of the work 17 by the application unit 1 and blow over the entire surface of the work by the blow unit 2 are performed. It becomes possible.

As described above, the application and removal of the desmear liquid are performed after a predetermined time. From this, the coating unit 1 and the blow unit 2 are connected to the processing lens 15 as described above.
It is not necessary to dispose them separately on both sides of the
May be arranged side by side.

In any case, space can be saved by incorporating the desmear apparatus into the laser drilling apparatus.

The desmear apparatus described above is applicable to all laser drilling apparatuses which require the removal of residual components. The present invention can also be applied to a laser processing apparatus using a multi-axis galvano scanner as described above.

[0032]

As described above, according to the present invention, residual components in via holes can be removed without using a liquid tank for a wet process, and the amount of processing liquid can be reduced. In addition, when incorporated into a laser drilling device, there is also the effect that the processing time is greatly reduced and space can be saved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a desmear apparatus according to the present invention.

FIG. 2 is a diagram showing a configuration of an example of a laser drilling apparatus to which the present invention is combined.

FIG. 3 is a diagram illustrating a configuration of an XY scanner illustrated in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coating part 1-1 Blowout nozzle 2 Blow part 2-1 Nozzle 3 Stage 10 Laser oscillator 11 Reflection mirror 13 Mask 14 XY scanner 14-1, 14-2 Galvano mirror 15 Processing lens 16 XY stage 17 Work

Claims (8)

[Claims] 1. A desmear apparatus for removing a residual component remaining in a via hole formed by irradiating a resin layer formed on a metal film on a workpiece with a laser beam from a laser oscillator in a laser drilling apparatus. And
Coating means for coating a desmear liquid on the surface of the resin layer,
A desmear apparatus for a laser drilling apparatus, comprising: a blow means for removing the applied desmear liquid. 2. The desmear device according to claim 1, wherein
The work is a square-shaped printed wiring board, and the coating means and the blowing means each have a coating area and a blowing area over the entire length of the printed wiring board in the width direction, and a desmear for a laser drilling apparatus. apparatus. 3. The desmear device according to claim 2, wherein
A desmearing apparatus for a laser drilling apparatus, wherein the coating means includes a plurality of blow-off nozzles for desmear liquid arranged in a line over the entire length of the printed wiring board in the width direction. 4. The desmear device according to claim 2, wherein
A desmear apparatus for a laser drilling apparatus, wherein the blow means comprises a plurality of nozzles for blowing a plurality of gases arranged in a line over the entire length of the printed wiring board in the width direction. 5. The desmear device according to claim 3, wherein
A desmear apparatus for a laser drilling apparatus, wherein each of the coating unit and the blowing unit includes a drive mechanism movable in a direction perpendicular to a width direction of the printed wiring board. 6. The desmear device according to claim 3, wherein
A stage for mounting the printed wiring board and moving the printed wiring board in a uniaxial direction, wherein the coating means and the blowing means respectively apply and blow the printed wiring board mounted on the stage over its entire length in the width direction; By moving the stage in the uniaxial direction, application over the entire surface of the printed circuit board by the application unit and blowing over the entire surface of the printed circuit board by the blowing unit are performed. A desmear apparatus for a laser drilling apparatus, wherein the desmear apparatus is configured as described above. 7. The desmear device according to claim 3, wherein
The laser drilling apparatus is an XY for mounting the printed wiring board and moving the printed wiring board in the X-axis direction and the Y-axis direction.
A stage, wherein the desmear apparatus is incorporated in the laser drilling apparatus, and the coating means and the blow means each extend over the entire length of the printed wiring board mounted on the XY stage in the width direction. The XY stage is moved in one of the X-axis direction and the Y-axis direction after the drilling of the work is completed, and the printing is performed by the coating unit. A desmearing apparatus for a laser drilling apparatus, characterized in that coating is performed over the entire surface of the wiring substrate and blowing over the entire surface of the printed wiring substrate by the blowing means is performed. 8. A step of irradiating a resin layer formed on a metal film in a work with a laser beam from a laser oscillator to form a via hole in the resin layer, and removing a residual component remaining in the via hole. A desmearing method for a laser drilling apparatus, comprising: performing a coating step of applying a desmear liquid to the surface of the resin layer and a blowing step of removing the applied desmear liquid.