KR101425492B1 - Laser machining apparatus and method thereof - Google Patents

Abstract

A laser processing apparatus and method are disclosed. The laser processing apparatus includes a beam combining unit for causing a plurality of laser beams to travel in the same direction with a predetermined angle so that a plurality of light converging points spaced from each other at a predetermined interval can be formed on the object to be processed; And a condenser lens for condensing a plurality of laser beams deflected by the scanner onto the object to be processed.

Description

Technical Field [0001] The present invention relates to a laser machining apparatus and method,

The present invention relates to a laser processing apparatus and method, and more particularly, to a laser processing apparatus and method that can simultaneously process two beams.

A laser processing apparatus irradiates an object to be processed with a laser beam emitted from a laser oscillator through a scanner. Thus, laser processing such as marking, exposure, etching, punching, and scribing on one plane of the object can be performed.

In the laser machining, there is a case where a machining interval has a constant pattern (interval) depending on the type of the substrate. When the scanner system is mounted on both of the two laser beams as in the current system, it is difficult to control due to the complicated equipment structure, and precision in repeated processing may be lowered.

Provided is a laser processing apparatus and method capable of 2-beam machining that can be applied to processing of the same pattern substrate having a narrow interval.

A laser beam machining apparatus according to an embodiment of the present invention includes a beam combining unit for causing a plurality of laser beams to travel in the same direction at a predetermined angle so that a plurality of light converging points spaced from each other at a predetermined interval can be formed on the object to be machined; A scanner for deflecting the plurality of laser beams incident from the beam combining unit; And a condenser lens for condensing a plurality of laser beams deflected by the scanner onto an object to be processed.

The beam combining unit includes: a first reflecting mirror for reflecting the first laser beam; A second reflection mirror for reflecting the second laser beam; One of the first laser beam reflected by the first reflecting mirror and the second laser beam reflected by the second reflecting mirror is reflected and the other is transmitted so that the first laser beam and the second laser beam travel in the same direction Wherein one of the first and second reflecting mirrors and the beam combiner are parallel and the other reflecting mirror and the beam combiner are arranged so as not to be parallel to each other, Two laser beams may be provided so as to proceed in the same direction with each other at a predetermined angle.

The beam combining unit may further include a beam splitter for branching the incident laser beam to form the first laser beam and the second laser beam.

The beam splitter may divide a laser beam incident from a single light source into a first laser beam and a second laser beam.

Wherein the beam splitter is a polarizing beam splitter for splitting an incident laser beam into a first laser beam and a second laser beam according to a polarization, and wherein a path of the first laser beam between the beam splitter and the beam combiner, And a wave plate for changing the polarization of the laser beam passing through any one of the plurality of laser beams.

The wavelength plate may be a half wave plate.

The beam combiner may be a polarization-dependent beam combiner that reflects and transmits the incident first laser beam and the second laser beam according to polarization.

A first light source for providing the first laser beam; And a second light source for providing the second laser beam.

The condensing lens may be a telecentric lens.

A laser machining method according to an embodiment of the present invention includes the steps of forming a plurality of light-converging points spaced apart from each other at a predetermined interval on an object to be processed so that a plurality of laser beams proceed in the same direction with a predetermined angle; A step of relatively moving the object and a plurality of light-converging points along a virtual line along which the object is to be cut; Wherein a plurality of modified regions are formed in the object to be processed by relatively moving the light-converging point of the plurality of laser beams and the object along the line along which the object is intended to be cut, And forming a line.

The step of forming the plurality of light-converging points at the predetermined intervals includes: a beam combining step of causing a plurality of laser beams to travel in the same direction with a predetermined angle; Deflecting the plurality of laser beams to a scanner; And converging a plurality of laser beams deflected by the scanner onto an object to be processed.

The beam combining step may include reflecting the first and second laser beams to the first and second reflection mirrors, respectively; Wherein one of the first laser beam reflected by the first reflecting mirror and the second laser beam reflected by the second reflecting mirror is reflected and the other is transmitted through the first reflecting mirror and the second reflecting mirror is parallel to any one of the first and second reflecting mirrors And combining the first laser beam and the second laser beam by a beam combiner disposed so as not to be parallel to the other reflection mirrors and advancing the first laser beam and the second laser beam in the same direction at a predetermined angle with each other.

And dividing the laser beam incident by the beam splitter into a first laser beam and a second laser beam to provide the laser beam to the first and second reflection mirrors.

The laser beam incident on the beam splitter may be a laser beam emitted from a single light source.

According to the laser machining apparatus according to various embodiments of the present invention, a multi-beam, for example, two-beam system can be implemented with a simple optical system configuration and can be used without a separate correction and control device. Such a laser machining apparatus is easy to control and ensures the precision of repetitive machining when used for processing a substrate having a narrow interval of the same pattern.

1 schematically shows a laser processing apparatus according to an embodiment of the present invention.
Figure 2 shows the optical path in the coupling unit of Figure 1;
3 schematically shows a laser processing apparatus according to another embodiment of the present invention.
Fig. 4 schematically shows a plurality of light-converging points formed so as to be spaced apart from the object to be processed by the laser processing apparatus according to the embodiment of the present invention.
5 to 8 show a process of cutting an object to be processed by using the laser processing apparatus according to the embodiment of the present invention.
Fig. 9 is a plan view showing a wafer on which a plurality of circuit boards are formed as an example of an object to be processed. Fig.

Hereinafter, a laser processing apparatus and method according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size or thickness of each element may be exaggerated for clarity of explanation.

1 schematically shows a laser processing apparatus according to an embodiment of the present invention. Figure 2 shows the optical path in the coupling unit of Figure 1;

Referring to FIGS. 1 and 2, a laser processing apparatus according to an embodiment of the present invention includes a plurality of laser beams, for example, first and second laser beams L1 and L2, A plurality of laser beams deflected by the scanner 200 to the object to be processed W; a plurality of laser beams deflected by the scanner 200; And a condensing lens 300 for condensing the light. The object W to be processed can be mounted on the stage 1. The laser processing apparatus includes a laser light source 10 and a beam splitter for splitting the laser beam L emitted from the laser light source 10 into a plurality of laser beams, for example, first and second laser beams L1 and L2 And may further include a divider 110. The laser light source 10 and the beam splitter 110 may correspond to a plurality of laser beams. The beam splitter 110 may be included in the configuration of the beam combining unit 100.

The beam combining unit 100 includes a first reflecting mirror 120 for reflecting the first laser beam L1, a second reflecting mirror 130 for reflecting the second laser beam L2, A beam combiner 150 for combining the first laser beam L1 and the second laser beam L2 reflected by the first and second reflecting mirrors 120 and 130 and advancing in the same direction with a predetermined angle, ).

The beam combiner 150 reflects one of the first laser beam L1 reflected by the first reflecting mirror 120 and the second laser beam L2 reflected by the second reflecting mirror 130, Thereby allowing the first laser beam L1 and the second laser beam L2 to travel in the same direction. 1 and 2 show an example in which the first laser beam L1 is reflected by the beam combiner 150 and the second laser beam L2 is transmitted.

The beam combiner 150 may include a polarization dependent beam combiner. For example, the beam combiner 150 may be provided to transmit the laser beam of the P polarization component and reflect the laser beam of the S polarization component. Alternatively, the beam combiner 150 may be provided to reflect the laser beam of the P polarization component and transmit the laser beam of the S polarization component. As another example, the beam combiner 150 may be provided to partially transmit an incident beam and partially reflect the incident beam.

In the beam combining unit 100, the beam combiner 150 and the first and second reflection mirrors 120 and 130 may be disposed on one of the first and second reflection mirrors 120 and 130, The mirror and beam combiner 150 may be parallel and the beam combiner 150 may not be parallel to the other one. For example, as illustrated in FIGS. 1 and 2, the beam combiner 150 and the first reflection mirror 120 are parallel, and the beam combiner 150 and the second reflection mirror 130 are not parallel to each other And may be arranged to form a predetermined angle. 1 and 2, when the first and second laser beams L1 and L2 are incident on the first and second reflection mirrors 120 and 130, respectively, the first reflection mirror 120 may be disposed such that the first laser beam L1 is incident at an incident angle larger than 45 degrees and the second reflecting mirror 130 is incident at an incident angle of approximately 45 degrees with respect to the second laser beam L2. In Fig. 1, the A1, A2, and A3 planes are parallel to each other, and the B plane is at an angle to the A3 plane. The A1 plane and the A2 plane correspond to the incident plane of the first reflection mirror 120 and the beam combiner 150 respectively and the B plane corresponds to the incident plane of the second reflection mirror 130. [

The first and second laser beams L1 and L2 combined by the beam combiner 150 are incident on the first and second reflecting mirrors 120 and 130 and the beam combiner 150, Direction.

The scanner 200 can deflect the incident first and second laser beams L1 and L2 and irradiate the laser beam L1 to a desired position of the object W. [

The condensing lens 300 is moved in the same direction at a predetermined angle by the beam combining unit 100 and the first and second laser beams L1 and L2 deflected by the scanner 200 are processed And is condensed at a predetermined position spaced apart from the object W by a predetermined distance d. The condensing lens 300 may include, for example, a telecentric lens. When the converging lens 300 is provided with the telecentric lens as described above, the first and second laser beams L1 and L2, which are incident within a predetermined angle range, can be vertically incident on the object W. Here, the condenser lens 300 may be an F-theta-telecentric lens whose position of the light-converging point is linearly determined according to the incident angle.

The distance between the first and second laser beams L1 and L2 irradiated on the object W is determined by the angles of the first and second laser beams L1 and L2 entering the condenser lens 300. [ That is, when the focal length of the condensing lens 300 is f and the angle formed by the first and second laser beams L1 and L2 is?, The first and second laser beams L1, L2) can be obtained by? H = f *?.

In this embodiment, the laser light source 10 emits a laser beam L as a single light source. The first and second laser beams L1 and L2 emitted from the laser light source 10 and branched by the beam splitter 110 may have a wavelength band that is transmissive to the object W. [ Also, the laser beams L1 and L2 may be ultra-short pulse laser beams having a pulse width of 1 μs or less, preferably a picosecond order or a pulse width of a femtosecond order. The peak power density of the laser beams L1 and L2 may be 1 10 ⁸ (W / cm 2) or more. The laser beams L1 and L2 have a very high light-condensing property and can converge to the diffraction limit.

The beam splitter 110 divides a laser beam L incident from a laser light source 10 which is a single light source into a first laser beam L1 and a second laser beam L2.

The beam splitter 110 may be a polarization beam splitter that splits the incident laser beam L into a first laser beam L1 and a second laser beam L2 according to the polarization. In addition, the beam splitter 110 may be provided to partially transmit the incident laser beam L and partially reflect the incident laser beam L.

When the beam splitter 110 has a polarization beam splitter and the beam combiner 150 includes a polarization dependent beam combiner, the first laser beam L1 directed toward the object W through the beam combining unit 100, A path of the first laser beam L 1 between the beam splitter 110 and the beam combiner 150 or a path of the second laser beam L 2 passing through the path of the second laser beam L 2, For example, a half-wave plate, which changes the polarization of the laser beam. 1 and 2 show an example in which the wave plate 140 is provided on the path of the second laser beam L2.

The beam splitter 110 is a polarization dependent beam splitter which transmits and reflects a laser beam L incident from a laser light source 10 according to polarization and transmits P polarized light components to form a second laser beam L2), and the S polarized light component is reflected so as to be the first laser beam L1. In this case, the beam combiner 150 of the beam combining unit 100 transmits the second laser beam L2 of the P polarization component, reflects the first laser beam L1 of the S polarization component, And may be provided to advance the laser beams L1 and L2 in the same direction. 1 and 2, the wave plate 140 is disposed on the path of the second laser beam L2 of the P polarization component so that the polarization of the second laser beam L2 is changed to include some S polarization component The light amount of the P polarization component of the second laser beam L2 transmitted through the beam combiner 150 is reduced so that the first laser beam L1 and the second laser beam L1, which travel in the same direction by the beam combiner 150, The relative amount of light of the laser beam L2 can be adjusted. As another example, when the wavelength plate 140 is disposed on the path of the S polarized light component of the first laser beam L1 instead of being disposed on the path of the P polarized light component of the second laser beam L2, The amount of light of the S polarized light component of the first laser beam L1 reflected by the beam combiner 150 is reduced so that the first laser beam L1 and the second laser beam L1, which travel in the same direction by the beam combiner 150, L2 can be adjusted. Here, the laser processing apparatus can be provided so as to rotate the wave plate 140. In this case, if the angle formed between the optical axis of the wave plate 140 and the polarization direction of the incident laser beam L1 or L2 is relatively adjusted, the amount of polarization change of the laser beam passing through the wave plate 140 can be changed The relative amount of the first laser beam L1 and the second laser beam L2 traveling in the same direction can be adjusted by the beam combiner 150 as desired.

1 and 2 show an example in which the laser beam L emitted from the laser light source 10 is incident on the beam splitter 110 through the one surface 110a of the beam splitter 110, 10 may be arranged such that the laser beam L emitted therefrom is incident on the beam splitter 110 through the other surface 110b of the beam splitter 110. [ In this case, the laser beam transmitted through the beam splitter 110 follows the optical path of L1 in Figs. 1 and 2, and the laser beam reflected by the beam splitter 110 passes through the optical path of L2 in Fig. 1 and Fig. The laser beam along the optical path of L1 is transmitted through the beam combiner 150 and the laser beam along the optical path of L2 is reflected by the beam combiner 150 so that the two laser beams proceed in the same direction.

In the above description, the beam splitter 110 and the beam combiner 150 are arranged to reflect the S polarized light component of the incident laser beam and to transmit the P polarized light component, but the embodiment of the present invention is not limited thereto And the beam splitter 110 and the beam combiner 150 may be arranged to reflect the P polarization component of the incident laser beam and transmit the S polarization component. The beam splitter 110 reflects the S polarized light component of the incident laser beam and transmits the P polarized light component. The beam combiner 150 reflects the P polarized light component of the incident laser beam and the S polarized light component May be provided. The beam splitter 110 reflects the P polarized light component of the incident laser beam and transmits the S polarized light component, and the beam combiner 150 reflects the S polarized light component of the incident laser beam and the P polarized light component May be provided. Since the propagation path of the laser beam in various cases can be sufficiently inferred from the above description, the description of the various modifications and the detailed description thereof will be omitted here.

1 and 2, the beam splitter 110 is a cubic type and the beam combiner 150 is a plate type, which is illustrated by way of example, and the embodiment of the present invention is not limited to such a shape. For example, the beam splitter 110 may be a plate type, the beam combiner 150 may be cubic type, and both the beam splitter 110 and the beam combiner 150 may be plate type or cubic type.

FIG. 3 is a schematic view of a laser processing apparatus according to another embodiment of the present invention. As compared with FIGS. 1 and 2, in place of using a single laser light source 10 for providing a plurality of laser beams, For example, the first and second laser light sources 50a and 50b. That is, the laser machining apparatus of this embodiment may include a first laser light source 50a for providing a first laser beam L1 and a second laser light source 50b for providing a second laser beam L2 . In this case, the first and second laser light sources 50a and 50b emit the first and second laser beams L1 and L2 toward the first reflection mirror 120 and the second reflection mirror 130, respectively . At this time, the beam splitter 110 as shown in FIGS. 1 and 2 may be omitted. Here, the first and second laser light sources 50a and 50b are arranged side by side so that the laser light emitted from one of the first and second laser light sources 50a and 50b is bent at a right angle The first laser beam L1 and the second laser beam L2 emitted from the first and second laser light sources 50a and 50b are reflected by the first reflection mirror 120 And the second reflection mirror 130, as shown in FIG. The first and second laser light sources 50a and 50b are arranged so as to emit laser beams in directions orthogonal to each other, transmit a part of a laser beam incident on a position where the laser beam is crossed, A beam splitter for reflecting the beam can be arranged. In this case, the beam directed to the first reflecting mirror 120 through the beam splitter 110 becomes the first laser beam L1, and the beam directed toward the second reflecting mirror 130 becomes the second laser beam L2.

Although a few modified examples of the plurality of laser beam providing units have been described above, various modifications and other equivalent embodiments are possible.

According to the laser machining apparatus according to various embodiments of the present invention as described above, a plurality of laser beams are caused to travel in the same direction with a predetermined angle, and a plurality of light-converging points And a plurality of modified regions are formed inside the object W by relatively moving the object W and the plurality of light-converging points along a virtual line along which the object is intended to be cut. This modified region forms a plurality of cutting lines serving as a reference for cutting.

The plurality of light-converging points are formed at predetermined intervals on the object W by combining the beams so that the plurality of laser beams travel in the same direction with a predetermined angle, deflecting the laser beams to the scanner 200, .

The beam combining is performed by, for example, reflecting the first and second laser beams L1 and L2 to the first and second reflecting mirrors 120 and 130 and reflecting the first and second laser beams L1 and L2 to the first and second reflecting mirrors 120 and 130, One of the first laser beam L1 and the second laser beam L2 reflected by the second reflection mirror 130 is reflected and the other is transmitted through the first and second reflection mirrors 120 And the second laser beam L2 is coupled by a beam combiner 150 arranged parallel to any one of the first and second reflecting mirrors 130 and 130 so as not to be parallel to each other. Accordingly, the first laser beam L1 and the second laser beam L2 can travel in the same direction at a predetermined angle with respect to each other.

According to the laser processing apparatus according to various embodiments of the present invention as described above, a reflection mirror parallel to the beam combiner 150, for example, a first laser beam L 1 reflected from the first reflection mirror 120, A reflection mirror not parallel to the beam combiner 150 such as a second laser beam L2 reflected from the second reflection mirror 130 is tilted with respect to the reference beam so that the first laser beam L2 on the object W And the light-converging point F1 (F2) of the second laser beams L1 and L2 are focused on the surface of the object W or at a predetermined depth at a predetermined interval d as shown in FIG. As the first and second laser beams L1 and L2 are deflected by the scanner 200, for example, the first and second laser beams L1, The light-converging points F1 and F2 of the beams L1 and L2 move as shown in Fig.

5 to 8 show a process of cutting the object W using the laser processing apparatus according to the embodiment of the present invention.

5 to 8, a plurality of laser beams L1 and L2 spaced apart from each other by a predetermined distance d are formed along a plurality of imaginary lines along which the material is to be divided A1 and A2, And is condensed on the inside of the object W to be processed, the multiphoton absorption which occurs near the light-converging point F1 (F2) or the physical and optical phenomenon equivalent thereto, Regions C1 and C2 are formed. The modified regions C1 and C2 form a plurality of cutting lines B1 and B2 for cutting in the thickness direction inside the object W to be processed.

When the laser beams L1 and L2 are condensed in the object W, the laser beams L1 and L2 are temporally and spatially compressed in the vicinity of the light-converging point F1 and F2, thereby locally forming extremely dense peak powers. Then, the laser beams L1 (L2) having transmittance with respect to the object W exhibit very high absorption characteristics locally due to multiphoton absorption or a nonlinear absorption effect equivalent thereto. The modified regions C1 and C2 in which the physical properties of the material are changed are formed inside the object W and the cutting lines B1 and C2 are formed in the object W by the modified regions C1 and C2, ) (B2) can be formed. After the cutting lines B1 and B2 are formed, a physical impact such as mechanical or thermal stress is exerted from the outside on the object to be processed W, or by a natural fracture, as shown in Figs. 7 and 8, The object W can be cut along the lines B1, B2. Since the local nonlinear absorption effect is exhibited only in the vicinity of the light-converging point F1 (F2) in the object W, the heat influence on the surface or the back surface of the object W can be reduced.

As described above, by using the laser processing apparatus according to the embodiment of the present invention, it is possible to form a plurality of cutting lines B1 and B2 by one machining using a plurality of laser beams L1 and L2 Therefore, the machining speed can be improved. For example, as shown in Fig. 9, when it is desired to cut the object W in the form of a wafer on which a plurality of circuit elements 11 are formed, Thereby reducing the time required for processing a single wafer.

Although the method of using the two laser beams L1 and L2 has been described above, the scope of the present invention is not limited thereto, and three or more laser beams may be moved in the same direction It is possible to simultaneously form three or more cutting lines by forming light-converging points on the object W at regular intervals.

According to the laser processing apparatus according to various embodiments of the present invention as described above, it is possible to realize a multiple beam, for example, a two beam system in a simple optical system configuration, and can be used without a separate correction and control device.

As described above, the laser processing apparatus according to various embodiments of the present invention can easily control and secure the precision of repeated processing when used for processing a substrate having a narrow interval of the same pattern.

10a, 50a, 50b, ..., a laser light source 100, a beam combining unit
110 ... beam splitter 120, 130 ... first and second reflection mirrors
140 ... wave plate 150 ... beam combiner
200 ... scanner 300 ... condenser lens
W ... object to be processed

Claims (14)

A beam combining unit for causing a plurality of laser beams to travel in the same direction with a predetermined angle so that a plurality of light converging points spaced from each other at a predetermined interval can be formed on the object to be processed;
A scanner for deflecting the plurality of laser beams incident from the beam combining unit;
And a condensing lens for condensing a plurality of laser beams deflected by the scanner onto an object to be processed,
The beam combining unit includes:
A first reflection mirror for reflecting the first laser beam;
A second reflection mirror for reflecting the second laser beam;
One of the first laser beam reflected by the first reflecting mirror and the second laser beam reflected by the second reflecting mirror is reflected and the other is transmitted so that the first laser beam and the second laser beam travel in the same direction And a beam combiner,
Wherein the first and second reflecting mirrors and the beam combiner are parallel and the remaining reflecting mirror and the beam combiner are disposed so as not to be parallel to each other so that the first and second laser beams coupled by the beam combiner And a laser processing device which moves in the same direction. delete The apparatus of claim 1, wherein the beam combining unit comprises:
And a beam splitter for branching the incident laser beam to form the first laser beam and the second laser beam. 4. The laser processing apparatus according to claim 3, wherein the beam splitter divides a laser beam incident from a single light source into a first laser beam and a second laser beam. 5. The apparatus of claim 4, wherein the beam splitter is a polarization beam splitter for splitting an incident laser beam into a first laser beam and a second laser beam according to a polarization,
And a wave plate for changing the polarization of the laser beam passing on any one of the path of the first laser beam between the beam splitter and the beam combiner and the case of the second laser beam. The laser processing apparatus according to claim 5, wherein the wave plate is a half wave plate. The laser processing apparatus according to claim 5, wherein the beam combiner is a polarization-dependent beam combiner that reflects and transmits the incident first laser beam and the second laser beam according to polarization. 2. The apparatus of claim 1, further comprising: a first light source for providing the first laser beam;
And a second light source for providing the second laser beam. 9. The laser processing apparatus according to any one of claims 1 to 8, wherein the focusing lens is a telecentric lens. A step of forming a plurality of light-converging points spaced apart from each other at a predetermined interval on the object to be processed so that the plurality of laser beams proceed in the same direction with a predetermined angle;
A step of relatively moving the object and a plurality of light-converging points along a virtual line along which the object is to be cut;
Wherein a plurality of modified regions are formed in the object to be processed by relatively moving the light-converging point of the plurality of laser beams and the object along the line along which the object is intended to be cut, And forming a line,
Wherein forming the plurality of light-converging points at the predetermined intervals comprises:
A beam combining step of causing a plurality of laser beams to travel in the same direction with a predetermined angle;
Deflecting the plurality of laser beams to a scanner;
And converging a plurality of laser beams deflected by the scanner onto an object to be processed,
The beam combining step includes:
Reflecting the first and second laser beams to the first and second reflection mirrors, respectively;
Wherein one of the first laser beam reflected by the first reflecting mirror and the second laser beam reflected by the second reflecting mirror is reflected and the other is transmitted through the first reflecting mirror and the second reflecting mirror is parallel to any one of the first and second reflecting mirrors And combining the first laser beam and the second laser beam by a beam combiner arranged so as not to be parallel to the other reflecting mirror, and advancing the first laser beam and the second laser beam in the same direction at a predetermined angle with each other. delete delete 11. The method of claim 10, further comprising branching a laser beam incident by the beam splitter into a first laser beam and a second laser beam to provide the laser beam to the first and second reflecting mirrors. 14. The method of claim 13, wherein the laser beam incident on the beam splitter is a laser beam emitted from a single light source.

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