JP3795816B2 - Laser processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing apparatus, and more particularly, to a laser processing apparatus that irradiates a workpiece with a laser beam oscillated from a laser oscillator and performs processing such as welding, drilling, or cutting.
[0002]
[Prior art]
Conventionally, as processing using laser light (hereinafter referred to as laser processing), processing techniques such as welding, drilling or cutting are used in manufacturing processes in various fields such as machines, electronics, and semiconductor devices.
[0003]
Here, an example of a laser processing apparatus having a conventional laser processing optical system will be described with reference to the drawings.
[0004]
FIG. 1 is a diagram of a configuration example of a conventional laser processing apparatus.
[0005]
The laser processing apparatus of FIG. 1 is configured to have a laser oscillator 10, a bending mirror 11, and a processing lens 12.
[0006]
The direction of the laser beam oscillated from the laser oscillator 10 is bent by the bending mirror 11, is imaged by the processing lens 12 that is an imaging optical system, and is irradiated on the surface of the processing target 13. By forming an image of the laser beam with the processing lens 12, a specific portion of the processing target 13 is melted or evaporated to realize processing such as welding, drilling or cutting.
[0007]
In general, in laser processing, the shape of a laser beam (beam mode) and its intensity are adjusted by a laser oscillator according to the material of the object to be processed, the details of the processing to be processed, and the like. A method of adjusting a laser beam using a mask or the like is also used.
[0008]
Here, as the types of beam modes emitted from the laser oscillator 10, there are shapes called single mode (Gaussian) and multimode (top flat), which are used properly according to the respective applications. Here, two typical beam modes of the conventional laser beam are shown in FIG.
[0009]
Here, FIG. 2A shows the waveform of the single mode energy density distribution, FIG. 2B shows the waveform of the multimode energy density distribution, the vertical axis shows the energy density, and the horizontal axis shows the distance from the center. Indicates. The waveform shown in FIG. 2 is viewed from the direction perpendicular to the optical axis (traveling direction) of the laser beam.
[0010]
As shown in FIG. 2, the single mode (FIG. 2A) has a distribution having a sharp peak in the center, and the multi mode (FIG. 2B) has a wide distribution of peaks. .
[0011]
In other words, the single mode is superior to the multimode in terms of light collection and is often used for fine cutting and the like. Therefore, via holes or through holes with a diameter of 100 μm or less can be easily formed. In the case of the multimode, for example, the conductor on the bottom surface of the via hole is less likely to be damaged, and the residue is less likely to remain on the bottom surface of the via hole.
[0012]
[Problems to be solved by the invention]
However, in the single mode, since only one strong waveform is extracted from the laser beam by a filter such as a mask or an aperture, the overall energy is weaker than in the multimode. In the case of the multi mode, since there is a peak width, a small diameter cannot be processed, and the diameter of the processed hole is increased.
[0013]
As a solution to the above problem, a conical beam mode (hereinafter referred to as a conical mode) that can have the advantages of both a single mode and a multimode can be considered. Here, an example of the conical beam mode is shown in FIG. The vertical and horizontal axes in FIG. 3 are the same as those in FIG. As shown in FIG. 3, by forming a so-called conical beam mode in which the energy density has a peak at the center of the laser beam and the energy density gradually decreases toward the periphery, the object to be processed is formed. On the other hand, it is possible to perform processing with a small diameter, and it is possible to have both the advantages of both single mode and multimode, such as less likely to cause damage to the workpiece and less residue.
[0014]
In addition, when the above-described conical mode is formed by using a mask imaging optical system using a mask, the energy is reduced by the mask when the laser beam emitted from the laser oscillator is a multimode. Not right. Further, when the conical mode output is enabled by the laser oscillator, it is necessary to purchase and replace an expensive laser oscillator, and the current apparatus is wasted.
[0015]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a laser processing apparatus in which processing quality by a laser is improved by forming a conical mode laser beam by a condensing optical system. To do.
[0016]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs means for solving the problems having the following characteristics.
[0017]
The invention described in claim 1, a laser processing apparatus including a laser oscillator for oscillating a laser beam of single mode or multimode, and a beam shaper for deforming the beam mode of the laser beam, the beam shaper, the The laser beam is refracted and synthesized to transform the beam mode into a conical beam mode.
[0018]
According to the first aspect of the present invention, by using the conical mode, it is possible to process a workpiece with a small diameter, hardly cause damage to the workpiece, and make it difficult for residues to remain. By combining the advantages of single mode and multimode, machining quality can be improved. Moreover, it can respond to various kinds of processing.
[0019]
The invention described in claim 2 is characterized in that the beam shaper is a condensing optical system.
[0020]
According to the second aspect of the present invention, as compared with the mask imaging optical system, it is possible to prevent a decrease in energy due to the mask or the like, and it is possible to efficiently form the conical mode and perform processing.
[0021]
According to a third aspect of the present invention, the beam shaper includes: a first lens that refracts the laser beam so that the incident laser beam is diffused or condensed; and a laser beam emitted from the first lens. And a second lens to be synthesized.
[0022]
According to the third aspect of the present invention, the conical mode can be formed corresponding to various laser beams (beam modes) oscillated from the conventional laser oscillator.
[0023]
According to a fourth aspect of the present invention, when the laser beam incident on the beam shaper is in a single mode, the first lens refracts the laser beam at the center of the laser beam to spread outward. It is characterized by.
[0024]
According to the fourth aspect of the present invention, when the laser beam oscillated from the laser oscillator is in the single mode, the energy of the central portion having a strong beam intensity is diffused to the outside, so that the single mode can be easily transformed into the conical mode. Can be made.
[0025]
According to a fifth aspect of the present invention, when the laser beam incident on the beam shaper is multimode, the first lens focuses the laser light around the laser beam at the center. It is characterized by being refracted.
[0026]
According to the fifth aspect of the present invention, when the laser beam oscillated from the laser oscillator is in the multimode, the laser beam in the peripheral portion is condensed so that the beam intensity in the central portion is increased, so that the cone is changed from the multimode to the cone. It can be easily transformed into a mode.
[0027]
The invention described in claim 6 is characterized in that the second lens synthesizes the laser beam emitted from the first lens into a conical beam mode.
[0028]
According to the sixth aspect of the present invention, the conical mode can be easily formed by using the laser beam emitted from the first lens.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
The present invention uses a condensing optical system to form a conical mode laser beam having the advantages of both single mode and multimode, and irradiates the object to be processed to improve the processing quality by laser processing. The main object is to provide a laser processing apparatus capable of performing the above.
[0030]
Here, embodiments of the present invention will be described with reference to the drawings.
[0031]
FIG. 4 is a diagram showing a configuration example of the laser processing apparatus according to the present invention.
[0032]
The laser processing apparatus of FIG. 4 is configured to include a laser oscillator 10, a venting mirror 11, a processing lens 12, and a beam shaper 31.
[0033]
In FIG. 4, first, when a laser beam is oscillated from the laser oscillator 10, the beam shaper 31 deforms the beam mode into a conical shape. The beam mode input to the beam shaper 31 may be either a single mode or a multi-mode, and the beam shaper 31 changes the optical system (lens) inside the beam shaper according to each beam mode.
[0034]
The laser beam transformed into the conical mode by the beam shaper 31 is incident on the machining lens 12 via the bending mirror 11, and the machining object 12 is irradiated with the laser beam imaged by the machining lens 12, and the machining is performed. .
[0035]
As described above, the laser oscillator 10 can form a conical mode beam mode having both single mode and multimode characteristics while using a conventional apparatus.
[0036]
Note that the position of the beam shaper 31 in the laser processing apparatus of the present invention may be set anywhere on the optical path until the laser beam emitted from the laser oscillator 10 reaches the workpiece 13. The configuration of the laser processing apparatus in the present invention is not limited to this. For example, the laser processing apparatus may have a mask portion, and the masked laser beam may be input to the beam shaper 31.
[0037]
Next, a configuration example of the condensing optical system in the beam mode 31 will be described with reference to the drawings.
[0038]
FIG. 5 is a diagram showing a configuration example of a beam shaper in the present invention. Here, FIG. 5A is a configuration example of the beam shaper (31-1) for deforming from the single mode to the cone mode, and FIG. 5B is a beam shaper for deforming from the multi mode to the cone mode. It is an example of a structure of (31-2).
[0039]
The beam shaper 31-1 in FIG. 5A is configured to include a diffusion lens 41 (first lens) and a synthesis lens 42 (second lens). Further, the beam shaper 31-2 in FIG. 5B is configured to include a condenser lens 43 (first lens) and a synthetic lens 42 (second lens).
[0040]
In FIG. 5A, when a single mode laser beam 44 is input to the beam shaper 31-1, the diffusing lens 41 is refracted by the lens so as to widen the center of the laser beam, and the peripheral portion of the laser beam is Each is output in the incident direction. That is, the portion having a high beam intensity at the central portion of the laser beam is refracted so as to diffuse around. Accordingly, laser beams having different traveling directions as shown in FIG. The outputted laser beam becomes a laser beam having a stronger energy at the periphery than the inputted single mode, and is synthesized by the synthesizing lens 42, and a laser beam forming a conical beam mode is outputted.
[0041]
On the other hand, in FIG. 5B, when the multimode laser beam 45 is input to the beam shaper 31-2, the condensing lens 43 refracts the laser beam so as to condense the peripheral portion of the laser beam, and also the laser beam. The central part of each is output in the incident direction as it is. That is, the laser beam peripheral portion is refracted so that the center portion has a flat beam intensity and the center portion becomes strong. Therefore, the output laser beam becomes a laser beam having a stronger energy in the center than the input multi-mode, and is synthesized by the synthesis lens 42 to output a laser beam forming a conical mode.
[0042]
In this embodiment, the beam shaper 31 is divided into a single mode 31-1 and a multimode 31-2 for ease of explanation. However, the beam shaper in the present invention is not limited to this. For example, a diffuser lens, a condensing lens, and a combining lens are included in one beam shaper, and a lens switching unit is provided, so that the diffuser lens 41 and the condensing lens 43 are set according to the input beam mode. And may be switched. Further, a control unit that controls the laser oscillator and the beam shaper may be provided, and may have a function of automatically switching between the diffusing lens and the condensing lens in accordance with the laser mode of the laser beam oscillated by the laser oscillator.
[0043]
The number of lenses in the beam shaper is not limited to this, and any configuration that outputs a conical mode laser beam may be used, and a mirror or a prism may be used instead of the lens.
[0044]
Next, a processing shape when laser processing is actually performed with a laser beam that is actually transformed into a conical mode using a beam shaper will be described with reference to the drawings.
[0045]
FIG. 6 is a diagram illustrating an example of a machining shape in the conical mode according to the present embodiment.
[0046]
In FIG. 6, in order to easily understand the effect of the present invention, FIG. 6A shows a cross section of a workpiece processed with a single mode laser beam without using a beam shaper, and FIG. The processing cross section of the workpiece by the conical mode laser beam using the beam shaper in the present invention is shown.
[0047]
Further, acrylic is used for the object to be processed, the pulse energy is 14.7 mJ, and the mask diameter when using the mask is Φ4.0.
[0048]
In the case of FIG. 6A, the depth from the surface (upper part of the figure) to the tip (lower part of the figure) reaches 195 μm. In addition, a step can be seen on the side surface of the processed hole. On the other hand, in the case of FIG. 6B, since the depth from the surface to the tip is 115 μm, the hole diameter is small without causing damage to the conductor on the tip surface of the blind hole (hole not penetrating). Processing can be performed. In addition, the side surface of the processed hole can be processed smoothly.
[0049]
As described above, according to the present invention, the quality of processing can be improved by using a conical mode laser beam. Further, by performing mode conversion from a beam mode such as a single mode or a multimode to a conical mode using a beam shaper, the conical mode can be formed at low cost without changing a conventionally expensive laser oscillator.
[0050]
Further, by providing the beam shaper with a lens corresponding to a beam mode such as a single mode or a multimode, it is possible to cope with various laser beams oscillated from a laser oscillator.
[0051]
In addition, as an object to be processed, it is possible to use an object that requires fine and accurate processing such as a printed board or an electronic component.
[0052]
【The invention's effect】
According to the present invention, laser beam processing such as welding, drilling, and cutting is performed by transforming the beam mode of a laser beam oscillated from a laser oscillator into a conical mode and irradiating the workpiece with the laser beam. The laser processing apparatus which can improve the quality of can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a conventional laser processing apparatus.
FIG. 2 is a diagram showing a beam mode of a conventional laser beam.
FIG. 3 is a diagram showing an example of a conical beam mode in the present invention.
FIG. 4 is a diagram of a configuration example of a laser processing apparatus according to the present invention.
FIG. 5 is a diagram illustrating a configuration example of a beam shaper according to the present invention.
FIG. 6 is a diagram illustrating an example of a machining shape in a conical mode according to the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Laser oscillator 11 Bending mirror 12 Processing lens 13 Processing object 31 Beam shaper 41 Diffusing lens 42 Synthetic lens 43 Condensing lens 44 Laser beam (single mode)
45 Laser beam (multimode)

Claims (6)

A laser processing apparatus comprising: a laser oscillator that oscillates a single-mode or multi-mode laser beam; and a beam shaper that deforms a beam mode of the laser beam,
The beam shaper refracts and combines the laser beam to transform the beam mode into a conical beam mode. The beam shaper is
The laser processing apparatus according to claim 1, wherein the laser processing apparatus is a condensing optical system. The beam shaper is
A first lens that refracts the laser beam so that the incident laser beam is diffused or condensed, and a second lens that synthesizes the laser beam emitted from the first lens. The laser processing apparatus according to claim 1. The first lens is
4. The laser processing apparatus according to claim 3, wherein when the laser beam incident on the beam shaper is in a single mode, the laser beam at the center of the laser beam is refracted so as to spread outward. The first lens is
4. The laser processing apparatus according to claim 3, wherein when the laser beam incident on the beam shaper is multimode, the laser beam around the laser beam is refracted so as to be focused at the center. 5. The second lens is
The laser processing apparatus according to claim 3, wherein the laser beam emitted from the first lens is combined into a conical beam mode.

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