JP2000263263A - Laser beam piercing method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam piercing device capable of displaying a plurality of laser beam irradiation regions decided by the parameter inputted by an operator as an irradiation pattern and displaying the evaluation result of piercing by the irradiation pattern. SOLUTION: A laser beam piercing device is provided with a data input device, a display device and a controller, is applied to irradiate an object to be pierced with a laser beam having a beam diameter and a beam cross sectional shape decided beforehand a plurality of times and to pierce the hole sufficiently larger than the beam cross sectional shape. The controller prepares the irradiation pattern showing the region array of a plurality of times of the laser beam irradiation on the basis of the algorithm decided beforehand by using the parameter inputted by an operator and displays the pattern on a display device, further prepares the evaluation in the case piercing is performed by the displayed irradiation pattern and displays the evaluation results on a display device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for making a hole by a laser beam.

[0002]

2. Description of the Related Art A schematic view of a conventional laser drilling apparatus is shown in FIG. The laser drilling apparatus mainly includes a laser oscillator 10, a mirror 11, a mask 13, an XY scanner 14, and a processing lens 15. The XY scanner 14 is configured by a movable mirror called a galvanometer mirror or the like, and has a function of changing the traveling direction of laser light emitted from the laser oscillator 10. Thus, a desired position on the processing target 17 placed on the processing table 16 is irradiated with laser light to perform drilling. The mask 13 is a shield for shaping the cross-sectional shape of the laser beam. The diameter of the hole formed in the processing target 17 can be changed by changing the diameter of the passage hole. In most cases, the shape of the passage hole of the mask 13 is designed to be circular, and as a result, the hole formed is also often circular.

Here, information necessary for drilling, that is, an instruction such as a position where drilling is performed by irradiating a laser beam and a diameter of a hole are performed by an operator by creating a data block defined by a laser drilling apparatus. This is performed by inputting to a laser drilling apparatus before processing via input means such as an operation terminal.

In particular, in drilling with a pulse laser, the depth of a hole that can be drilled by one pulse of laser light having the same energy is almost constant depending on the material of the workpiece 17. For this reason, when the working depth is required to be larger than that, it is necessary to irradiate the laser beam a plurality of times per one place. In addition, if the energy of the laser beam applied to the unit area does not exceed a threshold value corresponding to the material of the processing target 17, a phenomenon in which the processing speed rapidly decreases appears. This threshold value is called “fluence”. When the laser light is focused on the processing target 17 using an optical component such as the processing lens 15 or a concave mirror in order to secure energy exceeding this value. There are many. In other words, the conventional laser drilling apparatus cannot perform drilling of a large area by one irradiation of the laser beam.

Therefore, when drilling of a large area is necessary, it is common practice to perform processing by overlapping a large number of small area drills. However, in the case where the shape of the processing hole per pulse laser irradiation is circular, an area overlapping with the adjacent circular irradiation area occurs in order to completely fill the large area processing area without a gap. Since this overlapping area is processed twice in irradiation, as shown in FIG. 7, the processing is more advanced than the other areas. as a result,
The processing depth varies on the bottom surface of the processed hole.

[0006]

As described above, in the conventional drilling of a large area up to a certain depth, there is a quality problem such that the depth of the bottom surface of the processed hole varies. Alternatively, in a process of removing an insulating resin up to a conductive layer of copper, which is often used in a drilling process of a multilayer printed wiring board, there is an adverse effect that a conductive layer that should not be processed is damaged.

On the other hand, even if there is no problem even if there is a variation in the processing depth, if irradiation is performed so that the laser light overlaps more, a large number of laser irradiations are required to process the same area. That requires a lot of processing time.

Conventionally, the method of determining the position of the irradiation area in the case of superposition has been left to the setting based on the operation / judgment on the user side. In this case, a trial-and-error parameter determination action that requires a long time, such as an evaluation of whether or not a machining omission occurs or a determination of appropriateness based on a machining result, is required until the optimal machining method is determined. I do.

An object of the present invention is to provide a laser drilling method suitable for improving the processing quality of a large-diameter hole and improving the processing speed.

Another object of the present invention is to display a plurality of laser irradiation areas determined by parameters input by an operator as an irradiation pattern and to process the laser beam using this irradiation pattern. An object of the present invention is to provide a laser drilling apparatus capable of displaying an evaluation result in such a case.

[0011]

According to the present invention, a laser beam having a predetermined beam diameter and a predetermined beam cross-sectional shape is applied to a workpiece a plurality of times to form a hole having an area sufficiently larger than the predetermined beam cross-sectional shape. In the laser drilling method, the laser light irradiation is performed such that a shape connecting the centers of three mutually adjacent irradiation regions becomes an equilateral triangle and the overlapping area of the adjacent irradiation regions is minimized. For the irradiation of the laser beam that protrudes from the hole in the outermost irradiation region, the irradiation is performed such that the position is shifted toward the center of the hole along one side of the equilateral triangle so that the laser light fits in the hole. It is characterized by the following.

When the laser beam is a pulsed laser beam, the depth of the hole is determined by the number of times of repetitive irradiation to the same irradiation region.

According to the present invention, there is further provided a data input device, a display device, and a control device, wherein a laser beam having a predetermined beam diameter and a beam cross-sectional shape is irradiated to a processing object a plurality of times. In a laser drilling apparatus for drilling a hole having a sufficiently larger area than a shape, the data input device is for inputting a parameter defining an irradiation pattern, and the control device uses the input parameter to Based on a predetermined algorithm, create the irradiation pattern indicating the arrangement of the irradiation area of the laser light a plurality of times and display it on the display device, and create an evaluation result when drilling is performed with the irradiation pattern And the display pattern is displayed on the display device. As the irradiation region of the laser beam does not occur as much as possible the gap, laser drilling device is provided, wherein the addition overlap area of adjacent irradiated region is a pattern that fills to minimize.

[0014] As a result of the evaluation, the control device causes the display device to display a histogram of a variation in cross-sectional shape and depth at an arbitrary position of the hole when processed by the irradiation pattern.

[0015]

Embodiments of the present invention will be described below. The laser drilling machine according to this embodiment is
It is characterized in that a control device (not shown) having a function of evaluating a laser beam irradiation area determined by a parameter input by an operator before drilling is incorporated at the time of drilling.

A laser drilling machine incorporating such a control device determines a plurality of irradiation regions to be irradiated with laser light based on a predetermined algorithm using parameters input by an operator, and determines an irradiation pattern. , And predict and evaluate the processing results,
Information such as the arrangement (irradiation pattern) of the irradiation area on the processing target and a histogram of the variation in the processing depth is displayed on a display device (not shown) so that the operator can grasp the processing details. Thereafter, when an instruction to start actual machining is given, the laser drilling machine performs laser irradiation to perform machining based on parameters input by the operator. For this reason, the laser drilling apparatus according to the present embodiment includes a display device for displaying the evaluation result to the operator based on the output of the parameter evaluation function. Further, the laser drilling device includes an input device (not shown) for an operator to input parameters.

Although the evaluation results will be described later,
A display device for visualizing the arrangement of the irradiation area on the processing object in an image or generating a histogram of the variation of the processing depth in the hole to be processed so that the operator can easily grasp the processing details. To be displayed. Further, the effect of inputting these parameters and displaying the evaluation result can be further enhanced by enabling the operator and the control device to interactively perform the display via the display device.

Next, the contents of the parameters and the algorithm for creating the irradiation pattern will be described. FIG. 1 shows a case in which a circular hole 1 is processed by laser light irradiation seven times, and a laser light irradiation area is arranged as an apparent processed hole based on a regular irradiation pattern. In this arrangement, six processing holes (irradiation regions) having the same diameter are determined so as to symmetrically surround the center with respect to the center processing hole (irradiation region). Then, as for the three machined holes adjacent to each other, their centers form an equilateral triangle. The length of one side of the equilateral triangle that determines the center interval between the machined holes is one of the “parameters” in the present invention. In FIG. 1, assuming that the radius of the machined hole is r, the length of one side of the equilateral triangle is represented by (3) ^1/2 · r.

In order to secure a desired machining depth,
When irradiating the laser beam to the same portion a plurality of times, the laser beam is processed by arranging the irradiation pattern determined by the above-mentioned center interval parameter on the object to be processed for each layer. Such a position where each layer is arranged is defined as another “parameter”. This parameter has information of a two-dimensional position on the processing target, and is described in the same coordinate system as the data of the irradiation area for each layer.

These parameters are evaluated using an evaluation function. The smaller the variation of the processing depth and the lower the frequency of occurrence of the unprocessed area,
Outputs high evaluation results. Note that the “layer” referred to here is called for convenience in order to treat an irradiation pattern as a single unit, and it is not necessary that actual processing be performed with time for each irradiation pattern.

The evaluation function of the irradiation pattern for one layer is output as follows. When the processing hole formed by one irradiation has a columnar shape as shown in FIG. 7, an evaluation is performed on the surface of the processing target to determine the overlap of the processing holes in a plane. In this case, since the irradiation pattern is determined by the parameter of the center interval, a higher evaluation result is given as the overlap with the adjacent processing hole is smaller and the remaining area is smaller.

For example, as described with reference to FIG. 1, when the radius of the machined hole is r, the length of one side of the equilateral triangle is (3)
^{At 1/2 1} / 2r, the outer peripheries of three adjacent processing holes intersect at one point, so that no remaining processing area is generated. In this state, there is no region irradiated with the laser beam three times or more, and the area irradiated twice is smaller than in other cases, so that the variation in the processing depth is suppressed. Therefore, in this case, the highest evaluation result of the parameter of the center interval is given.

Next, let us consider a case where a processed hole formed by one irradiation has a taper as shown in FIG. In laser drilling, the cross-sectional shape of a processing hole on a processing target object often has an inclined portion called a taper. The shape of the taper can be defined using, for example, a hole diameter on the top surface of the object to be processed and a hole diameter on the bottom surface. If there is a taper, the depth of the machined hole will not be constant in the hole, so the evaluation method is as follows. In each case where the center distance between adjacent machining holes is changed, the inside of an equilateral triangle, which is a basic component of the irradiation pattern, is divided into many parts, and the depth of the holes when a plurality of tapered machining holes are superimposed. Is calculated at each of the divided positions to evaluate the processing. At all positions, a high evaluation result is given to a parameter having a small variation in the processing depth and a small remaining processing area.

In the case where the above-mentioned machined hole is cylindrical, it is possible to integrate the case where the hole diameter on the upper surface is equal to the hole diameter on the bottom surface when there is a taper.

The evaluation function for each layer is calculated by dividing the object to be processed into a number of parts and processing depth at each position from the result of superimposing the processing results for each layer using the layer arrangement parameters. However, the smaller the variation and the lower the frequency of occurrence of the unprocessed area, the higher the evaluation result is given to the parameter.

By the way, as shown in FIG. 3, the hole 1 is not necessarily formed on the outer periphery of the hole when a large area is drilled.
In some cases, the contour of the outer periphery of ′ does not match the end of the irradiation pattern. In this case, the operator is required to change the outer processing hole indicated by the broken line to the hole 1 to be processed in FIG. 3 displayed on the display device.
When it is confirmed that the outer processing hole does not protrude from the contour of the outer periphery of the hole 1 ′, the center of the outer processing hole is not changed as shown by a solid line in FIG. Modify the parameter to reduce the interval parameter. In this case, the center interval r 'in the outer processing hole is r'<(3) ^1/2 · r. In this case, as the overlapping area with the adjacent processing hole increases, the variation in the processing depth increases, and the evaluation result deteriorates. However, it is unavoidable.

FIG. 4 shows a case where the area of the hole 2 to be machined is larger than that of FIG. Here, when the same value as that of FIG. 1 is input as a parameter relating to the center interval, the center interval (3) described with reference to FIG.
The irradiation pattern has an arrangement relationship of ^1/2 · r. Of the twelve outermost processing holes, the center distance between the six processing holes in the contour of the outer periphery of the hole 2 and the six processing holes in the middle is (3) ^{1 This} is an irradiation pattern having an arrangement relationship of ^{/ 2} · r. On the other hand, as for the six machined holes protruding from the contour line of the outer periphery of the hole 2, as described in FIG.
When a parameter change is input by the operator, the position of the hole 2 is shifted toward the center of the hole 2 so as to fit in the hole 2.

When inputting minimum parameters such as the diameter of a hole processed by one irradiation and the area of a hole to be processed, appropriate parameters are generated.
You may make it show to an operator.

FIG. 5 shows a display example by the display device. In FIG. 5, seven irradiation patterns of laser light are created by the control device based on the algorithm described above using the input parameters, and displayed on the display device. In addition, the control device creates an evaluation result when drilling is performed with the displayed irradiation pattern and causes the display device to display the evaluation result. As a result of the evaluation, a cross-sectional shape of the hole at an arbitrary position (for example, in a diametrical direction) when the hole is processed by the displayed irradiation pattern, and a histogram of a variation in the processing depth are displayed on the display device. The parameters input by the operator include the pitch of the irradiation area (hole to be processed by one irradiation), the diameter of the hole to be processed, the material of the object to be processed, and when the hole to be processed by one irradiation has a taper. The taper angle, the etching rate and the like are displayed.

When drilling a large area using the laser drilling apparatus according to this embodiment, the operator first
Input the conditions necessary for processing and the parameters that define the irradiation pattern. The control device predicts and evaluates a machining result generated from these pieces of information, and presents the information to the operator via a display screen. The operator checks the evaluation result, determines whether the parameters are appropriate, and determines the arrangement of the irradiation pattern. If the operator determines that the parameter is not appropriate, the operator re-enters the parameter and performs the evaluation again. As a result of the evaluation, when the operator determines that the parameters are appropriate, when an instruction to start actual machining is given,
The laser drilling device performs drilling based on the designated parameter values.

[0031]

The laser drilling apparatus according to the present invention is
Processing with less variation in depth at the bottom surface of the hole than in the conventional method can be efficiently processed in a shorter time. Further, trial and error test processing can be reduced, and processing that is less dependent on the skill of the operator can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an irradiation pattern when a large-area hole is machined according to the present invention.

FIG. 2 is a view for explaining a relationship between adjacent processing holes when a processing hole having a taper is formed by one laser irradiation;

FIG. 3 is a diagram for explaining a countermeasure in a case where a part of an irradiation pattern protrudes from a hole to be processed;

FIG. 4 is a diagram illustrating an example of an irradiation pattern when a hole having a larger area than the hole in FIG. 1 is machined;

FIG. 5 is a diagram showing a display example of parameters, irradiation patterns, and evaluation results displayed by the display device according to the present invention.

FIG. 6 is a diagram for explaining a schematic configuration of a laser drilling apparatus to which the present invention is applied.

FIG. 7 is a cross-sectional view for describing a depth of a processing hole when two laser beams are irradiated so as to overlap with each other.

[Explanation of symbols]

 1, 1 ', 2 holes 11 Mirror 15 Processing lens 16 Processing table 17 Processing object

Claims (5)

[Claims] 1. A laser drilling method for irradiating a processing object with a laser beam having a predetermined beam diameter and a beam cross-sectional shape a plurality of times to form a hole having a sufficiently larger area than the beam cross-sectional shape. Light irradiation is performed so that the shape connecting the centers of three mutually adjacent irradiation areas becomes an equilateral triangle,
The plurality of irradiation regions are determined so that the overlapping area of the adjacent irradiation regions is minimized, and the irradiation of the laser light protruding from the hole in the outermost irradiation region is performed along one side of the equilateral triangle. A laser drilling method, characterized in that the laser beam is irradiated so as to fit in the hole while being shifted toward the center. 2. The laser drilling method according to claim 1, wherein the laser light is a pulsed laser light, and the depth of the hole is determined by the number of times of repeated irradiation on the same irradiation area. Drilling method. 3. The laser drilling method according to claim 1, wherein said hole has a circular shape. 4. A processing device comprising a data input device, a display device, and a control device, wherein a laser beam having a predetermined beam diameter and a beam cross-sectional shape is irradiated to a processing object a plurality of times, and is sufficiently larger than the beam cross-sectional shape. In a laser drilling apparatus for drilling a hole having an area, the data input device is for inputting a parameter that defines an irradiation pattern, and the control device is configured with an algorithm predetermined using the input parameter. The irradiation pattern showing the arrangement of the irradiation area of the laser light for a plurality of times is created based on the display pattern and displayed on the display device, and the evaluation result when drilling is performed with the irradiation pattern is created to display the display device. The irradiation pattern is,
The processing region corresponding to the hole is a pattern in which the irradiation region of the laser light is filled so that the irradiation region of the plurality of times does not generate a gap as much as possible, and furthermore, the overlapping area of the adjacent irradiation regions is minimized. Laser drilling equipment. 5. The laser drilling apparatus according to claim 4, wherein, as the evaluation result, the control device determines a variation in cross-sectional shape and depth at an arbitrary position of the hole when the hole is processed by the irradiation pattern. A laser drilling apparatus, wherein a histogram is displayed on the display device.