TWI632971B - Laser processing apparatus and laser processing method - Google Patents

Abstract

The invention discloses a laser processing device and a laser processing method. A laser processing apparatus according to the present invention includes: a light beam generating unit that emits a plurality of laser beams; a plurality of scanners that adjust paths of a plurality of laser beams emitted from the light beam generating unit; and a telecentric lens unit, The laser beam reflected from the scanner is incident to converge the laser beam in such a manner that the incident laser beam is incident perpendicularly to the workpiece.

Description

Laser processing device and laser processing method

The present invention discloses a laser processing apparatus and discloses a laser processing apparatus that can adjust the position and angle of a laser beam irradiated to a workpiece.

Generally, a laser processing process is a process of processing a laser beam toward a surface of a workpiece to process a shape or a physical property of the surface of the workpiece. Such a workpiece may have a plurality of examples, and its shape may be a two-dimensional planar shape. As an example of the laser processing process, a process of forming a polysilicone film by crystallizing an amorphous silicon film by scanning a laser beam on a germanium wafer is exemplified.

The quality of the product of such a processing depends on the position, direction, time, etc. of the laser beam irradiated to the workpiece. In the laser processing process, the light beam emitted from the light source is divided into a plurality of beams while being irradiated, or the laser beam emitted from the light source is moved to the position of the workpiece by operating the scanner. However, in this case, the angle at which the laser beam is irradiated to the workpiece changes depending on the path of the laser beam. Further, as a result, the processed shape of the workpiece formed by the laser beam changes, which adversely affects the laser processing quality.

Therefore, even if a plurality of laser beams are irradiated at the same time or the irradiation position of the laser beam is changed, it is necessary to fixedly maintain the angle at which the laser beam is irradiated to the workpiece. Moreover, in order to accurately control the machining position, an observation technique that can observe the process of the laser processing process is required.

[Problem to be Solved by the Invention] The present invention provides a laser beam processing process for dividing a laser beam emitted from a laser light source into a measuring beam and a processing beam, and then measuring the optical characteristics of the measuring beam. A laser measuring device, a laser processing system, and a laser measuring method that are defective in the laser beam. [Means for solving the problem]

In one aspect, a laser processing apparatus includes: a beam generating portion that emits a plurality of laser beams; and a plurality of scanners that adjust paths of a plurality of laser beams emitted from the beam generating portion; The telecentric lens portion is incident on a laser beam reflected from the scanner to condense the laser beam so that the incident laser beam is incident perpendicularly to the workpiece.

The laser beam reflected from the scanner can pass through the center of the aperture of the telecentric lens portion.

The above laser processing apparatus may further include a scanner driving unit that adjusts the position and angle of the scanner.

The scanner driving unit can adjust the position and angle of the scanner such that the laser beam reflected from the scanner passes through the center of the aperture of the telecentric lens unit.

The laser processing apparatus may further include an imaging unit that captures a case where a laser beam emitted from the telecentric lens unit is irradiated onto the processed object.

The above laser processing apparatus may further include a dichroic mirror provided on the aperture of the telecentric lens portion.

The above laser processing apparatus may further include an illumination source that illuminates the dichroic mirror with illumination light.

The dichroic mirror can be formed by transmitting light for the wavelength of the laser beam and reflecting the light for the wavelength of the illumination light.

In another aspect, a laser processing apparatus is provided, comprising: a light source; a diffractive optical element (DOE) that divides a light beam emitted from the light source into at least two light beams; and a telecentric lens portion The light beam split by the above-described diffractive optical element is incident perpendicularly to the workpiece.

The above laser processing apparatus may further include a rotary table that controls a rotation angle of the first diffractive optical element.

In another aspect, a laser processing method is provided, comprising the steps of: emitting a beam of light from a plurality of laser beams; and causing a plurality of laser beams emitted from the beam exiting step to be incident on the telecentric lens portion a step of adjusting a light path of the laser beam; and a step of concentrating the laser beam by the telecentric lens portion to vertically inject the laser beam into a workpiece.

The laser processing method may include the steps of: irradiating illumination light to a dichroic mirror provided on the aperture of the telecentric lens portion; and capturing the laser beam by measuring the illumination light reflected by the processed object; The step of irradiating to the above-mentioned processed object. [Effect of the invention]

According to the embodiment, there is provided a concentrating point detecting device capable of accurately and stably detecting the position of a condensing point of a processing beam even if the concentrating optical system fluctuates and the thickness of the workpiece changes.

In the following drawings, the same reference numerals are given to the same components, and the size of each component may be exaggerated in the drawing for clarity and convenience of description. On the other hand, the embodiments described below are merely examples, and various modifications can be made according to the embodiments.

Terms such as the first and second terms can be used to describe various constituent elements, but the constituent elements should not be limited by the terms. The term is used only for the purpose of distinguishing one component from other components.

As long as the other meanings are not explicitly indicated in the text, the singular expression includes the plural expression. In addition, when a part is "included" as a certain component, unless otherwise indicated, it means that it may include other components, and does not mean that other components are excluded.

Further, terms such as "parts" and "modules" described in the specification refer to units that process at least one function or operation.

FIG. 1 is a view showing a state in which a laser beam is collected by a normal focus lens unit 10. In FIG. 1, an example in which the lens portion 10 includes the first lens 12, the second lens 14, the third lens 16, and the fourth lens 18 is shown, but the above is merely an example, and the lens included in the lens portion 10 can be changed. Number and shape.

Referring to Fig. 1, a light beam passing through an aperture of the lens portion 10 can form light collecting points P0, P1, and P2 on the light collecting surface via the lens portion 10. The center light of the light beam incident in parallel with the optical axis of the lens portion 10 can be vertically irradiated to the light collecting surface. That is, the angle θ0 between the center light and the condensing surface can be close to 90 degrees. However, the center light of the light beam that is not incident parallel to the optical axis of the lens portion 10 is not perpendicularly irradiated to the light collecting surface. For example, the angle θ1 between the center light of the light beam forming the light collecting point P1 and the condensing surface may become less than 90 degrees. Further, the angle θ2 between the center light of the light beam forming the light collecting point P2 and the condensing surface may become smaller than θ1. That is, the farther the distance between the optical axis of the lens portion 10 and the light collecting point is, the smaller the angle between the center light of the light beam and the light collecting surface is.

As shown in FIG. 1, even if a light beam is irradiated to the inside of the aperture of the lens portion 10, the shape and incident angle of the laser beam collected on the condensing surface change depending on the incident angle.

2A and 2B are views schematically showing a laser processed shape formed by a laser beam passing through the lens portion 10 shown in Fig. 1. FIG. 2A shows a case where laser processing is performed in the vicinity of the optical axis of the lens unit 10, that is, in the vicinity of the condensing point P0. 2B shows a case where laser processing is performed at a position away from the optical axis of the lens unit 10, that is, in the vicinity of the light collecting points P1 and P2.

Referring to FIG. 2A, in the vicinity of the optical axis of the lens portion 10, the center light of the laser beam is vertically irradiated to the workpiece, and thus the laser processed shape may have a symmetrical shape. Conversely, referring to FIG. 2B, at the position of the optical axis of the lens portion 10, the center light of the laser beam is obliquely irradiated to the workpiece, and thus the laser processing shape is changed. If the shape of the laser processing changes as described above, it will adversely affect the laser processing quality.

FIG. 3 is a view showing a state in which a laser beam is irradiated to the telecentric lens portion 20 of the exemplary embodiment.

Referring to Fig. 3, the light passing through the center C of the aperture of the telecentric lens portion 20 can be uniformly irradiated to the incident surface at all times regardless of the incident angle. Since the exit pupil of the telecentric lens portion 20 is close to infinity, the light irradiated to the aperture can be collected in the same shape regardless of the incident angle. However, the position of the condensed spot changes depending on the incident angle of the incident beam irradiated to the aperture. As an example, the incident angle of the incident beam, the distance between the condensed spot and the optical axis may satisfy the relationship as in [Formula 1].

[Formula 1] h=f×θ

In Formula 1, h represents the distance between the condensed point and the optical axis of the telecentric lens portion 20, f represents the effective focal length of the telecentric lens portion 20, and θ represents the angle between the optical axis of the telecentric lens portion 20 and the incident beam. Referring to [Formula 1], it is understood that the larger the angle between the optical axis of the telecentric lens portion 20 and the incident beam, the larger the distance between the light collecting point and the optical axis of the telecentric lens portion 20. Therefore, the position of the condensed spot can be adjusted by adjusting the incident direction of the incident beam. For example, in FIG. 3, a light beam incident at an angle of α1 with respect to the optical axis may form a light collecting point at a position away from the optical axis h1=f*α1. Further, the light beam incident at an angle of α2 with respect to the optical axis can form a light collecting point at a position away from the optical axis h2=f*α2.

In FIG. 3, the telecentric lens portion 20 is shown to include a concave lens 22, two convex lenses 26, 28, and a lens 24 that is recessed on the left side and protruded on the right side. However, the telecentric lens portion 20 may be any other lens arrangement that allows light incident on the center C of the aperture to be emitted in parallel. In the present invention, the aperture 29 is illustrated to facilitate understanding of the invention, but the aperture is a position and a range for indicating the characteristics of the lens, and may not be a member actually present. As described above, the exit pupil of the light beam passing through the aperture of the telecentric lens can be infinite, and the light incident to the aperture can be condensed in the same shape as the incident angle without light. Fig. 4 is a view schematically showing a laser processing apparatus of an exemplary embodiment. The laser processing apparatus shown in FIG. 4 may include the telecentric lens portion 20 shown in FIG. For convenience, the telecentric lens portion 20 is simply shown as a square in FIG.

Referring to FIG. 4, the laser processing apparatus of the exemplary embodiment may include a beam generating portion (not shown) that emits a plurality of laser beams, and a plurality of scanners 32, 34, 36, 38 for the self-beam generating portion. The path of the plurality of laser beams (not shown) is adjusted; and the telecentric lens portion 20 is irradiated with laser beams reflected from the plurality of scanners 32, 34, 36, 38 to cause the incident laser The above-described laser beam is condensed in such a manner that the beam is irradiated perpendicularly to the workpiece.

As shown in FIG. 4, the light beam generating portion (not shown) may cause the first to fourth light beams L1, L2, L3, L4 to be incident on the first to fourth scanners 32, 34, 36, 38, respectively. The configuration of the light beam generating portion can be variously changed. For example, the light beam generating portion may include a plurality of light sources. As another example, the light beam generating unit may further include: a light source; and a spectroscopic optical system that splits the light beam emitted from the one light source into the plurality of light beams L1, L2, L3, and L4 and transmits the first to fourth scans to the fourth scan Instruments 32, 34, 36, 38.

The first to fourth scanners 32, 34, 36, 38 may pass the first to fourth light beams L1, L2, L3, L4 through the center C of the aperture 29 of the telecentric lens portion 20. Here, the opening position and size of the diaphragm 29 of the telecentric lens portion 20 can be changed according to the size of the telecentric lens portion 20 and the lens characteristics. Therefore, the positions and arrangement angles of the first to fourth scanners 32, 34, 36, 38 may also vary depending on the size of the telecentric lens portion 20 and the lens characteristics.

If the first to fourth beams L1, L2, L3, L4 pass through the center C of the aperture 29 of the telecentric lens portion 20 by the first to fourth scanners 32, 34, 36, 38, the first The light beam to the fourth light beams L1, L2, L3, L4 may pass through the telecentric lens portion 20 and be irradiated to the workpiece 5 in parallel with each other. That is, the first to fourth light beams L1, L2, L3, and L4 can be irradiated to the workpiece 5 at the same angle. Thereby, the plurality of laser beams L1, L2, L3, and L4 can be irradiated to the workpiece 5 in the same direction and the same beam shape. By irradiating the plurality of laser beams L1, L2, L3, and L4 with the same characteristics to the workpiece 5 at a time, the laser processing speed can be improved and the laser processing quality can be improved.

4, an example in which the positions and angles of the first to fourth scanners 32, 34, 36, and 38 are fixed so that the laser beams L1, L2, L3, and L4 having the same characteristics are incident on the workpiece 5 at a time are shown. . However, the embodiment is not limited to this.

Fig. 5 is a view schematically showing a laser processing apparatus according to another exemplary embodiment. When the embodiment of FIG. 5 is described, the content overlapping with FIG. 4 is omitted.

Referring to FIG. 5, the laser processing apparatus of the exemplary embodiment may include: a light beam generating portion (not shown) that emits the first laser beam L1 and the second laser beam L2; and the first scanner 31 and the second The scanner 33 illuminates the first light beam L1 and the second light beam L2, respectively. Here, the number of laser beams emitted from the light beam generating unit (not shown) and the number of scanners are merely examples, and are not limited thereto. In the embodiment shown in FIG. 5, the positions and angles of the first scanner 31 and the second scanner 33 may vary. Therefore, the positions at which the first light beam L1 and the second light beam L2 form the light collecting point in the workpiece 5 may be changed according to the positions and angles of the first scanner 31 and the second scanner 33.

Although not shown, the laser processing apparatus of the exemplary embodiment may include a scanner driving unit (not shown) that adjusts the position and angle of the first scanner 31 and the second scanner 33. The scanner driving section can adjust the position and arrangement angle of the scanners 31, 33. The scanner driving unit can adjust the positions and angles of the scanners 31 and 33 so that the light beams L1 and L2 reflected from the scanners 31 and 33 pass through the center of the diaphragm 29 of the telecentric lens unit 20.

Fig. 6 is a view showing an example in which the scanner driving unit adjusts the position and angle of the scanner.

Referring to FIG. 6, when the scanner forms an angle of β1 with the light beam emitted from the light source 50, the light beam L1 reflected from the scanner can pass vertically along the optical axis of the telecentric lens portion 20 through the center of the aperture 29 of the telecentric lens portion 20 Irradiation to the workpiece 5. Here, in order to change the position where the light beam is condensed to the workpiece 5, the angle between the traveling direction of the light beam reflected from the scanner and the optical axis of the telecentric lens portion 20 can be changed as described with reference to [Formula 1]. However, if the angle of the light beam reflected from the scanner is adjusted, the light beam L21 reflected from the scanner will not pass through the center C of the aperture 29 of the telecentric lens portion 20. Then, even if the light beam L21 passes through the telecentric lens portion 20, it is obliquely irradiated to the workpiece 5.

Therefore, the position of the scanner can be changed such that the light beam reflected from the scanner passes through the center C of the diaphragm 29 of the telecentric lens portion 20. That is, by changing the angle of the scanner from β1 to β2, the position of the scanner can be changed from P1 to P2. Thereby, the light beam L22 reflected from the scanner is irradiated perpendicularly to the workpiece 5, and the position where the light beam L22 is irradiated to the workpiece 5 can be changed.

In order to accurately control the operation of the scanner driving unit shown in Fig. 6, it is necessary to measure the course of the laser processing process at any time. For this reason, the laser processing apparatus of the exemplary embodiment shown in FIG. 4 and FIG. 5 may further include an imaging unit for capturing the case where the laser beam emitted from the telecentric lens unit 20 is irradiated to the workpiece 5 . . Hereinafter, an example in which the laser processing apparatus of the embodiment shown in FIG. 5 further includes an imaging unit will be described with reference to the drawings.

Fig. 7 is a view showing a laser processing apparatus of another exemplary embodiment.

Referring to FIG. 7, the laser processing apparatus of the embodiment may further include an imaging unit 90. The imaging unit 90 is a device for capturing illumination light reflected from the surface of the workpiece 5, and may include a charge coupled device (CCD) camera 92 and a collecting lens 94. The CCD camera 92 is merely an example, and may be replaced by other components that can perform light sensing. The illumination light reflected from the surface of the workpiece 5 may also use the reflected light of the laboratory internal illumination, but an illumination source 70 may be additionally provided. In the case where the laser processing apparatus includes another illumination light source 70, the imaging unit 90 may further include a beam splitter 96 for transmitting a part of the light emitted from the illumination light source 70 to self-process A part of the illumination light reflected by the object 5 is reflected toward the CCD camera 92 side.

Normally, the processing laser beams L1 and L2 are also reflected by the workpiece 5, and if the reflected processing laser beams L1 and L2 are irradiated to the CCD camera 92 of the imaging unit, it not only adversely affects the captured image but also causes the device. Damaged. In order to prevent the above, the laser processing apparatus of the embodiment may include a dichroic mirror 39 provided to the diaphragm 29 of the telecentric lens portion 20. The dichroic mirror 39 can transmit or reflect light according to the wavelength. For example, the dichroic mirror 39 can transmit most of the light without reflection for the wavelength of the processing laser beam. Thereby, it is possible to prevent the processing laser beams L1 and L2 from being irradiated onto the imaging unit 90. Conversely, the dichroic mirror 39 can reflect most of the light for the wavelength of the illumination light emitted from the illumination light source 70. Thereby, most of the illumination light reflected from the workpiece 5 can be transmitted to the imaging unit 90. The position of the dichroic mirror 39 is merely an example, and may vary depending on the configuration of the optical system and the requirements of the product.

The CCD camera 92 of the imaging unit 90 can capture the illumination light reflected from the workpiece 5 to provide a captured image. The laser processing process can be checked at any time based on the above captured images.

In the above embodiment, an embodiment in which a plurality of light beams are incident on the telecentric lens portion 20 by the scanner has been described. Hereinafter, an example in which a plurality of light beams are incident on the telecentric lens unit 20 by a diffractive optical element (DOE) will be described.

Fig. 8 is a view schematically showing a laser processing apparatus according to another exemplary embodiment.

Referring to FIG. 8, the laser processing apparatus of the exemplary embodiment may include: a light source (not shown) for illuminating the laser beam; and a diffractive optical element 62 for dividing the light beam emitted from the light source into at least two beams; The telecentric lens unit 20 irradiates the light beam divided by the diffractive optical element 62 perpendicularly to the workpiece.

The diffractive optical element 62 can split the irradiated one laser beam into a plurality of light beams by using a diffraction phenomenon of the laser beam. When the laser beam is divided by the diffractive optical element 62, an effect of simultaneously adjusting the laser beam at a plurality of positions of the workpiece can be obtained. Moreover, the processing form of the workpiece is determined by the design of the diffractive optical element 62. The light beam emitted from the light source can be split into a plurality of light beams via the diffractive optical element 62. Further, the light beam split by the diffractive optical element 62 can be vertically irradiated to the workpiece 5 through the telecentric lens portion 20.

In FIG. 8, the laser beam obtained by the division is irradiated onto one processing line D1 on the workpiece 5. When the state is such that the rotation angle θ of the diffractive optical element 62 is 0°, the position at which the laser beam is irradiated onto the workpiece 5 can be changed by changing the rotation angle θ of the diffractive optical element 62.

FIG. 9 is a view showing an example in which the diffractive optical element 62 shown in FIG. 8 is rotated.

Referring to Figure 9, the diffractive optical element 62 can be rotated by a specified angle (0 < θ < 90 °). In order to rotate the diffractive optical element 62, the laser processing apparatus can include a rotating stage. When the diffractive optical element 62 is rotated by the turntable, the divided laser beams can be irradiated to different processing lines D1 and D2, respectively. That is, two processes can be simultaneously performed on the workpiece 5.

In the above description, a plurality of items are specifically described, but these matters are not intended to limit the scope of the invention, but should be construed as an example of a preferred embodiment. Therefore, the scope of the invention should not be limited by the illustrated embodiments, but should be defined by the technical idea recited in the claims.

5‧‧‧Processing

10‧‧‧Lens Department

12‧‧‧ first lens

14‧‧‧second lens

16‧‧‧ third lens

18‧‧‧Fourth lens

20‧‧‧ Telecentric lens section

22‧‧‧ concave lens

24‧‧‧Lens with the left side recessed and the right side protruding

26, 28‧‧ ‧ convex lens

29‧‧‧Aperture of the telecentric lens

31‧‧‧First Scanner

33‧‧‧Second scanner

32, 34, 36, 38‧‧ ‧ scanner

39‧‧‧ dichroic mirror

50‧‧‧Light source

62‧‧‧Diffractive optical components

70‧‧‧Light source for illumination

90‧‧‧Photography Department

92‧‧‧CCD camera

94‧‧‧ Concentrating lens

96‧‧‧beam splitter

C‧‧‧ Aperture Center

D1, D2‧‧‧ processing line

H1, h2‧‧‧ distance

L1, L2‧‧‧Laser beam/beam

L21, L22‧‧‧ beams

L3, L4‧‧‧Laser beam/beam

P0, P1, P2‧‧‧ spotlights

Α1, α2, β1, β2, θ0, θ1, θ2‧‧‧ angle

FIG. 1 is a view showing a state in which a laser beam is collected by a general focus lens unit. 2A and 2B are views schematically showing a laser processed shape formed by a laser beam passing through the lens portion shown in Fig. 1. Fig. 3 is a view showing a state in which a laser beam is irradiated to a telecentric lens portion of an exemplary embodiment. Fig. 4 is a view schematically showing a laser processing apparatus of an exemplary embodiment. Fig. 5 is a view schematically showing a laser processing apparatus according to another exemplary embodiment. Fig. 6 is a view showing an example in which the scanner driving unit adjusts the position and angle of the scanner. Fig. 7 is a view showing a laser processing apparatus of another exemplary embodiment. Fig. 8 is a view schematically showing a laser processing apparatus according to another exemplary embodiment. Fig. 9 is a view showing an example in which the diffractive optical element shown in Fig. 8 is rotated.

Claims (8)

A laser processing apparatus comprising: a beam generating portion that emits a plurality of laser beams; a plurality of scanners that adjust paths of the plurality of laser beams emitted from the beam generating portion; and a telecentric a lens portion that is incident on the laser beam reflected from the scanner to condense the laser beam in such a manner that the incident laser beam is incident perpendicularly to a workpiece, wherein The laser processing apparatus further includes a scanner driving portion that adjusts a position and an angle of the scanner, the scanner driving portion passing the laser beam reflected from the scanner through the telecentric lens portion The manner of the center of the aperture adjusts the position and angle of the scanner. The laser processing apparatus according to claim 1, further comprising an imaging unit configured to capture a situation in which the laser beam emitted from the telecentric lens unit is irradiated to the workpiece. The laser processing apparatus according to claim 2, further comprising a dichroic mirror disposed in the aperture of the telecentric lens portion. The laser processing apparatus of claim 3, further comprising an illumination source that illuminates the dichroic mirror with illumination light. The laser processing apparatus according to claim 4, wherein the dichroic mirror is configured to transmit light of a wavelength of the laser beam to reflect light of a wavelength of the illumination light. A laser processing apparatus comprising: a light source; a diffractive optical element that splits the light beam emitted from the light source into at least two beams by a diffraction phenomenon of a light beam emitted from the light source; and a telecentric lens a portion that vertically injects the at least two light beams obtained by dividing the diffractive optical element into a workpiece, wherein the laser processing apparatus further includes a rotation that controls a rotation angle of the diffractive optical element station. A laser processing method comprising the steps of: emitting a beam exiting a plurality of laser beams; and causing the plurality of laser beams emitted in the beam exiting step to be incident on the telecentric lens portion a step of adjusting a light path of the laser beam; a step of concentrating the laser beam by the telecentric lens portion to vertically inject the laser beam into a workpiece; and The dichroic mirror of the aperture of the telecentric lens portion illuminates the illumination light. The laser processing method of claim 7, comprising the steps of: photographing the laser beam to the workpiece by measuring the illumination light reflected by the workpiece The steps of the situation.