KR102143187B1 - Laser processing apparatus and laser processing method using the same - Google Patents

Abstract

A laser processing apparatus according to an embodiment of the present invention includes a laser light source for processing; A first beam splitter disposed in a path of the processing laser beam emitted from the processing laser light source; A first light focusing unit focusing the processing laser beam transmitted through the first beam splitter onto an object to be processed; And a focus measurement module configured to measure a focus position of the processing laser beam by detecting an image of light reflected from the processing object; wherein the focus measurement module includes a measurement for emitting a measurement laser beam to be reflected from the processing object Dragon laser light source; A mask disposed on a path of the measuring laser beam toward the object to be processed, and blocking a part of the measuring laser beam to transform a single beam shape into two split beam shapes; And an image sensor configured to detect images of the two split beams reflected from the object to be processed through the mask.

Description

Laser processing device and laser processing method using the same {LASER PROCESSING APPARATUS AND LASER PROCESSING METHOD USING THE SAME}

The present invention relates to a laser processing apparatus and a laser processing method using the same.

Laser processing technology uses various methods such as forming a groove on the surface of the object to be processed by irradiating a laser to the object to be processed, forming a deteriorated layer inside the object to be processed, or changing material properties by applying heat to the object to be processed. It is being applied.

In recent years, as the trend of high density, high integration, and high precision has become clear in the semiconductor and display fields, the need for ultra-precise ultra-high-speed laser processing technology is expanding.

Ultra-precision ultra-fast laser processing technology has many application possibilities in scientific and industrial fields such as nano optics, nano photons, plasmons, nano electrons, and nano magnetism through the ability to produce high-resolution nano-scale 3D patterns.

However, since the work must be performed at an ultra-high speed, laser processing has a limit in focusing conditions. Due to the limitation of the focusing condition, there are problems that result in a decrease in processing quality, destruction of an object to be processed, a decrease in resolution, and low productivity.

Particularly, in a field requiring ultra-precise workability, it is very important to accurately position the object to be processed at the focus (focus) position of the laser beam where the highest light energy and the smallest beam spot size are obtained.

An aspect of the present invention is to provide a laser processing apparatus capable of measuring focus.

Another aspect of the present invention is to provide a laser processing method capable of laser processing at a focus position by using a laser processing device capable of measuring focus.

A laser processing apparatus according to an embodiment of the present invention includes a laser light source for processing; A first beam splitter disposed in a path of the processing laser beam emitted from the processing laser light source; A first light focusing unit focusing the processing laser beam transmitted through the first beam splitter onto an object to be processed; And a focus measurement module configured to measure a focus position of the processing laser beam by detecting an image of light reflected from the processing object; wherein the focus measurement module includes a measurement for emitting a measurement laser beam to be reflected from the processing object Dragon laser light source; A mask disposed on a path of the measuring laser beam toward the object to be processed, and blocking a part of the measuring laser beam to transform a single beam shape into two split beam shapes; And an image sensor configured to detect images of the two split beams reflected from the object to be processed through the mask.

In the mask, a first through-hole and a second through-hole penetrating the mask along a traveling direction of the measuring laser beam are formed, and the first through-hole is disposed at a center based on a cross section of the measuring laser beam. , The second through-hole may be disposed to be spaced apart from the first through-hole by a predetermined distance within the cross-section of the measuring laser beam.

The focus measurement module may include a second beam splitter disposed in a path of a measurement laser beam that has passed through the mask; And a second light focusing unit disposed between the second beam splitter and the image sensor, wherein the first beam splitter receives a measurement laser beam reflected from the object to be processed and is directed toward the second beam splitter. The second beam splitter may be disposed to be reflected, and the second beam splitter may be disposed such that the measuring laser beam reflected from the first beam splitter is incident and reflected toward the image sensor.

In the image sensed by the image sensor, a control unit for adjusting the position of the object to be processed so that a distance value between the two split beams becomes a set reference value.

The focus measurement module may further include a light emission unit disposed between the measurement laser light source and the mask to adjust a divergence angle of the measurement laser beam.

The light emitting unit may include a first lens to emit light and a second lens to focus light.

A stage for supporting the object to be processed may be further included, and the stage may be moved along a direction in which the processing laser beam travels by the control unit.

The focus measurement module may further include an optical filter disposed between the second beam splitter and the second optical focusing unit to pass only the measurement laser beam.

A laser processing method according to an embodiment of the present invention is a laser processing method using the laser processing device, comprising: finding a focus position of the processing laser beam by placing a measurement specimen instead of the processing object; Setting a measurement value in the reflected image as a reference value by irradiating the measurement laser beam onto the measurement specimen positioned at a focus position of the processing laser beam; Arranging the object to be processed instead of the specimen for measurement, and irradiating the laser beam for measurement from the object to adjust the position of the object to be processed so that the measured value in the reflected image matches the reference value; And processing the object to be processed by irradiating the laser beam for processing.

In the step of finding the focus position, while moving the measurement specimen along the traveling direction of the processing laser beam, a point at which the line width processed on the measurement specimen becomes a minimum value may be found.

In the mask, a first through hole disposed in the center based on a cross section through which the measurement laser beam passes, and a second through hole disposed spaced apart from the first through hole by a predetermined distance are formed, and set as the reference value. The step includes transforming the single beam shape into the two split beam shapes and irradiating the measurement specimen at the focus position; Sensing, by the image sensor, a first image of two split beams reflected from the measurement specimen; And setting a first measurement value obtained by measuring a distance between the two split beams in the first image as a reference value.

In the irradiating step, it is possible to adjust the divergence angle of the measuring laser beam.

Adjusting the position of the object to be processed may include placing the object to be processed instead of the specimen for measurement; Transforming the measuring laser beam into the two split beams and irradiating the object to be processed; Sensing, by the image sensor, second images of two split beams reflected from the object to be processed; Comparing a second measurement value obtained by measuring a distance between the two split beams in the second image with the reference value; And adjusting the position of the object to be processed so that the second measured value matches the reference value.

In the step of detecting the second image by the image sensor, the position of the image sensor may be adjusted.

According to an embodiment of the present invention, it is possible to easily and accurately measure a focus position of a laser beam for processing by using an image of two split beams.

In addition, according to an embodiment of the present invention, by positioning the object to be processed at the focus position of the laser beam for processing, the object to be processed can be processed more precisely.

1 is a perspective view schematically showing a laser processing apparatus according to an embodiment of the present invention.
2 is a schematic diagram showing a laser processing apparatus according to an embodiment of the present invention in two dimensions.
3 is a view showing a mask in the laser processing apparatus shown in FIGS. 1 and 2.
4 is a diagram illustrating an exemplary image detected by an image sensor among the laser processing apparatuses shown in FIGS. 1 and 2.
FIG. 5 is a diagram illustrating an embodiment of a light emitting unit of the laser processing apparatus shown in FIGS. 1 and 2.
6 is a flowchart illustrating a laser processing method according to an embodiment of the present invention.
7 is a diagram illustrating a process of finding a focus position in a laser processing method according to an embodiment of the present invention.
8 is a graph showing a change in a processed line width according to a position change of a specimen for measurement in the process shown in FIG. 7.
9 is a diagram illustrating a process of setting a reference value using a laser beam for measurement in a laser processing method according to an embodiment of the present invention.
10 is a diagram illustrating a process of positioning an object to be processed at a focus position in a laser processing method according to an embodiment of the present invention.
11 is a diagram illustrating an exemplary image of a laser beam for measurement detected by an image sensor in the process shown in FIG. 10.
12 is a diagram illustrating a state in which the measurement range of an image is expanded by moving an image sensor during the process illustrated in FIG. 10.
13 is a diagram illustrating a process of processing an object to be processed at a focus position with a laser beam for processing in a laser processing method according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented in many different forms and is not limited to the embodiments described herein.

In the drawings, parts not related to the description are omitted in order to clearly describe the present invention, and the same reference numerals are attached to the same or similar elements throughout the specification.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, so the present invention is not necessarily limited to the illustrated bar.

Throughout the specification, when a part is said to be "connected" with another part, this includes not only the case of being "directly connected", but also "indirectly connected" with another member therebetween. Also, when a part is said to “include” a certain component, this means that other components may be further included rather than excluding other components, unless otherwise stated.

In addition, in the present specification, "forward" and "rear" in the path of the laser beam mean "a position further advanced in the direction in which the laser beam travels" and "a position further advanced in the opposite direction in which the laser beam travels".

1 is a perspective view schematically showing a laser processing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a laser processing apparatus according to an embodiment of the present invention in two dimensions.

1 and 2, the laser processing apparatus 100 according to an embodiment of the present invention includes a processing laser light source 120, a first beam splitter 141, a first light focusing part 131, and a processing And a focus measurement module for measuring the focus position of the laser beam L2.

The processing laser light source 120 is a configuration that emits a processing laser beam L2 for processing the object 10, and generates a processing laser beam having a nanosecond laser, a picosecond laser, or a femtosecond laser pulse for ultra-precision processing. I can. For example, the processing laser beam L2 may have a wavelength of 1064 nm.

The first beam splitter 141 is disposed in the path of the processing laser beam L2 to reflect and transmit a part of the processing laser beam L2.

The first light focusing part 131 is disposed behind the first beam splitter 141 in the path of the processing laser beam L2 toward the object 10 to be processed, and transmitted through the first beam splitter 141. The processing laser beam L2 is focused on the object 10 to be processed.

The processing laser beam L2, which is focused on the object 10 in the form of a fine spot, processes the object 10 to be processed by forming a groove on the surface of the object 10. For processing, the focus of the processing laser beam L2 needs to be accurately positioned at the processing position of the processing object 10. For example, the object to be processed 10 may be fixed to a first stage (not shown) capable of multi-axis movement so that the position relative to the laser beam L2 for processing may be adjusted. When processing the surface of the object to be processed 10 , It is necessary to adjust the position of the processing object 10 by moving the first stage through a control unit (not shown) so that the focus of the processing laser beam L2 can be positioned on the surface of the processing object 10. That is, in order to position the object 10 to be processed at the focus position of the processing laser beam L2, it is an important task to be preceded by the laser processing operation to find the correct focus position of the processing laser beam L2. The laser processing apparatus 100 according to an embodiment of the present invention includes a focus measurement module for finding an accurate focus position of the processing laser beam L2, which will be described in detail below.

3 is a diagram illustrating a mask among the laser processing apparatuses shown in FIGS. 1 and 2, and FIG. 4 is a diagram illustrating an exemplary image detected by an image sensor among the laser processing apparatuses shown in FIGS. 1 and 2. .

The focus measurement module consists of components for measuring the focus position of the processing laser beam L2, and referring to FIGS. 1 and 2, the measurement laser light source 110, the mask 150, and the image sensor 190 Includes. That is, the measurement laser beam L1 emitted from the measurement laser light source 110 is transformed into two split beams through the mask 150, and the two split beams are reflected by irradiation on the object to be processed 10. By sensing the image of the image sensor 190, it is possible to measure the focus position.

In more detail, according to an embodiment of the present invention, in the image detected by the image sensor 190, the current object 10 is processed by comparing the measured value of the position between the two split beams with a preset reference value. It is possible to check whether the beam is positioned at the focus position of the beam L2, and by adjusting the position of the object to be processed 10 so that the above-described measured value matches the reference value, the laser beam for processing the object 10 is accurately processed. Can be placed at the focus position of

The measurement laser light source 110 is configured to emit a measurement laser beam L1 for measuring the focus position of the processing laser beam L2, and may be, for example, a diode laser, and a measurement laser The beam L1 may have a wavelength of 655 nm.

The mask 150 is arranged in the path of the measuring laser beam L1 toward the object 10 to be processed, and blocks a part of the measuring laser beam L1 to transform a single beam form into two split beam forms. to be. As shown in FIG. 3, according to an embodiment of the present invention, the mask 150 includes a first through hole 151 and a second through hole 151 penetrating the mask 150 along the traveling direction of the measurement laser beam L1. Since the through hole 152 is formed, the measuring laser beam L1 in the form of a single beam passing through the mask 150 can be transformed into the form of two split beams.

According to an embodiment of the present invention, the first through hole 151 is disposed in the center based on the cross-section through which the measuring laser beam L1 passes (a region indicated by a dotted line in FIG. 3), and the second through hole The 152 may be disposed to be spaced apart from the first through hole 151 by a predetermined distance d _m within the cross section of the measuring laser beam L1.

The image sensor 190 is a component that detects an image of the laser beam L1 for measurement in the form of two split beams emitted by irradiation on the object 10 and reflected, and may be composed of various image sensors. have. For example, it may be configured as a CCD, but is not limited thereto.

Referring to FIG. 4, it can be seen that the image sensor 190 detects images I ₁ and I ₂ for two split beams. In this way, by transforming the measurement laser beam L1 from a single beam form to two split beam forms through the mask 150, an image of two split beams, not a single beam, can be detected.

According to an embodiment of the present invention, the image sensor 190 is fixed to a second stage (not shown) that can move on the xy plane in FIGS. 1 and 2, and adjusts its position on the xy plane through a control unit (not shown). This may be possible, which will be described again later in the related content.

1 and 2, the focus measurement module further includes a light divergence unit 170, a second beam splitter 142, an optical filter 180, a second light focusing unit 132, and a control unit (not shown). Can include.

The light diffusion unit 170 is configured to adjust the divergence angle of the measurement laser beam L1 and may be disposed between the measurement laser light source 110 and the mask 150. FIG. 5 is a diagram illustrating an embodiment of a light emitting unit of the laser processing apparatus shown in FIGS. 1 and 2.

Referring to FIG. 5, the light emission unit 170 may allow the measurement laser beam L1 emitted from the measurement laser light source 110 to be diverged by a predetermined angle θ to proceed. This is to facilitate setting the reference value at the focus position of the processing laser beam L2.

In more detail, in the absence of the light emitting unit 170, the measurement laser beam L1 transformed into two split beams through the mask 150 is detected by the image sensor 190, and in the image detected by the image sensor 190, two split beams Since the distance between the two is substantially very close, the measurement resolution for the distance between the two split beams on the image may be poor. However, when the two split beams are emitted at a predetermined angle through the light emitting unit 170, the distance between the two split beams may be further increased in the image of the two split beams detected by the image sensor. Therefore, it is possible to improve the measurement resolution for the distance between the two split beams on the image.

Referring to FIG. 5, the light emitting unit 170 may include a first lens 171 that emits light and a second lens 172 that focuses light. The first lens 171 and the second lens 172 may be sequentially disposed on the path of the measuring laser beam L1, and may be spaced apart by a predetermined distance D.

At this time, by adjusting the distance D between the first lens 171 and the second lens 172, the divergence angle θ of the measuring laser beam L1 may be adjusted. For example, based on the sum of the focal lengths of the first lens 171 and the second lens 172, the divergence angle θ increases as the distance D spaced apart from that value is increased. To this end, at least one of the first lens 171 and the second lens 172 is fixed to a third stage (not shown) movable in the y-axis direction based on FIG. The divergence angle θ can be adjusted through the control of the stage.

Referring to FIGS. 1 and 2, the second beam splitter 142 is a configuration that transmits and reflects a part of light, and may be disposed in the path of the measurement laser beam L1 that has passed through the mask 150. . That is, the second beam splitter 142 may be disposed behind the mask 150 based on the path of the measuring laser beam. Accordingly, a part of the measurement laser beam L1 in the form of two split beams may be transmitted.

According to an embodiment of the present invention, the second beam splitter 142 may be disposed in parallel with the first beam splitter 141. That is, referring to FIGS. 1 and 2, the first beam splitter 141 is disposed so that the measuring laser beam L1 reflected from the object 10 is incident and reflected toward the second beam splitter 142. , The second beam splitter 142 may be disposed so that the measuring laser beam L1 reflected from the first beam splitter 141 is incident and reflected toward the image sensor 190.

The second light focusing unit 132 is disposed between the second beam splitter 142 and the image sensor 190 to focus light reflected through the second beam splitter 142 to the image sensor 190 .

The optical filter 180 is configured to pass only light of a predetermined wavelength band, and may be disposed between the second beam splitter 142 and the second light focusing unit 132. In this case, the optical filter 180 may be configured to pass only the measurement laser beam L1 among the incident measurement laser beam L1 and processing laser beam L2.

1 and 2, the laser processing apparatus 100 according to an embodiment of the present invention includes the reflected light of the laser beam L2 for processing reflected from the object 10 and the reflected light of the laser beam L1 for measurement. All are configured to proceed toward the image sensor 190. In this case, when the high-power processing laser light source 120 is used for precise processing, the processing laser beam L2 may cover the measurement laser beam L1 having a lower output. In this case, since it is difficult for the image sensor 190 to properly measure the image of the relatively low-power measurement laser beam L1, it can be configured so that only the measurement laser beam L1 is transmitted through the optical filter 180. have.

Hereinafter, a laser processing method using the above-described laser processing apparatus 100 will be described.

6 is a flowchart illustrating a laser processing method according to an embodiment of the present invention.

6, in the laser processing method according to an embodiment of the present invention, a focus position checking step of finding a focus position of a processing laser beam using a measurement specimen (S601), of a measurement laser beam at a focus position A reference value setting step (S602) of setting a reference value using an image, a position adjustment step (S603) of adjusting the position of the object to be processed by comparing the image of the laser beam for measurement on the object to be processed (S603), and a processing step. .

First, the step of confirming the focus position (S601) will be described. 7 is a view showing a process of finding a focus position in a laser processing method according to an embodiment of the present invention, and FIG. 8 is a view showing a change in a processed line width according to a change in the position of a specimen for measurement in the process shown in FIG. 7. This is the graph shown.

Referring to FIG. 7, instead of the object to be processed, the measurement specimen 11 is fixed to the first stage (not shown), and the processing laser light source 120 is operated to measure the processing laser beam L2. Investigate in. At this time, the processing laser beam L2 is irradiated to the measurement specimen 11 through the first beam splitter 141 and the first light focusing unit 131, and the measurement specimen 11 is a processing laser beam L2. Is processed by For example, suppose that a processing operation of forming a line on the surface of the measurement specimen 11 is in progress, as shown in FIG. 8, the line width processed on the measurement specimen 11 is of the processing laser beam L2. It is formed finest at the focus position. Therefore, referring to FIGS. 7 and 8, when processing is performed while moving the measurement specimen 11 in the traveling direction of the processing laser beam L2, that is, in the z-axis direction in FIG. 7, the finest line width appears. The focus position of the processing laser beam L2 can be checked. Accordingly, when the position of the measurement specimen 11 is fixed at the focus position, the processing position of the measurement specimen 11 becomes the focus position of the processing laser beam L2 at that time.

Through the above process, the focus position (hereinafter, the focus position) of the processing laser beam L2 is checked, the specimen for measurement is fixed to the focus position, and then the reference value setting step (S602) proceeds. The reference value setting step (S602) ) Will be described in detail.

9 is a diagram illustrating a process of setting a reference value using a laser beam for measurement in a laser processing method according to an embodiment of the present invention.

Referring to FIG. 9, the image sensor 190 detects reflected light by irradiating a measurement laser beam L1 onto a measurement specimen 11 positioned at a focus position.

In more detail, the measurement laser beam L1 emitted from the measurement laser light source 110 is emitted at a predetermined angle θ through the light emission unit 170, and the first through hole 151 (see FIG. 3) and the first 2 While passing through the mask 150 in which the through hole 152 (refer to FIG. 3) is formed, it is transformed into two split beams and proceeds. The measuring laser beam L1 in the form of two split beams passes through the second beam splitter 142 and is reflected by the first beam splitter 141, and is then focused by the first light focusing unit 131 to measure the specimen It is investigated in (11). At this time, since the measurement laser beam L1 is radiated through the light diverging unit 170 and proceeded, the measurement specimen 11 is irradiated with a distance between the two split beams through. The irradiated measuring laser beam L1 in the form of two split beams is reflected from the measurement specimen 11 and passes through the first light focusing unit 131 to the first beam splitter 141 and the second beam splitter 142. Each is reflected from and proceeds toward the image sensor 190. After being reflected by the second beam splitter 142, only the measurement laser beam L2 passes through the optical filter 180, passes through the second optical focusing unit 132, and is focused on the image sensor 190. As a result, since the measurement laser beam L1 is emitted and proceeds through the light emitting unit 170, light may be received by the image sensor 190 in a state where the distance between the two split beams is spaced apart.

In this case, the images detected by the image sensor 190 are detected in the form of two split beams spaced apart from each other. Referring to FIG. 3, an image I ₁ of a split beam passing through the first through hole 151 and an image I ₂ of a split beam passing through the second through hole 152 can be detected by the image sensor. There are two images (I ₁ , The distance between I ₂ ) is the distance (d _f ) from the focus position, and this is set as a reference value. That is, in the image of the measurement laser beam L1 in the form of two split beams reflected from the measurement specimen 11 (hereinafter, referred to as the first image), the distance d _f between the two split beams is set as a reference value. .

At this time, according to an embodiment of the present invention, in order to increase the measurement resolution of the distance d _f between the two split beams in the first image, the divergence angle of the measuring laser beam L1 through the light diverging unit 170 Can be greatly adjusted. In addition, when the distance d _f between the two split beams in the first image is too large, the divergence angle of the measuring laser beam L1 may be adjusted to be small through the light diverging unit 170.

After setting the reference value by the above-described method, a position adjustment step (S603) of adjusting the position of the object to be processed proceeds, and the position adjustment step (S603) will be described below.

FIG. 10 is a view showing a process of placing a target object at a focus position in a laser processing method according to an embodiment of the present invention, and FIG. 11 is a view of a laser beam for measurement detected by an image sensor in the process shown in FIG. FIG. 12 is a diagram illustrating an exemplary image, and FIG. 12 is a diagram illustrating a state in which a measurement range of an image is expanded by moving an image sensor during the process illustrated in FIG. 10. 13 is a diagram illustrating a process of processing an object to be processed at a focus position with a laser beam for processing in a laser processing method according to an embodiment of the present invention.

Referring to FIG. 10, instead of the specimen 11 for measurement, the object 10 to be actually processed is disposed, and then the laser beam L1 for measurement is irradiated. For example, after the measurement specimen 11 is removed from the first stage where the measurement specimen 11 is fixed, the object 10 is fixed to the first stage.

At this time, the first stage is positioned to correspond to the focus position of the processing laser beam L2, that is, the first stage is positioned so that the measurement specimen is in the focus position when the measurement specimen is fixed to the first stage. Since the measurement specimen 11 and the object to be processed 10 are not completely identical in size or thickness, etc., if the object to be processed 10 is fixed to the first stage corresponding to the focus position, the object to be processed 10 is positioned at the correct focus position. Not, and a position error occurs. Therefore, by moving the position of the object 10 to be processed, the object 10 must be accurately positioned at the focus position before processing.

As shown in FIG. 10, in the position adjustment step (S603), after replacing the measurement specimen 11 with the object 10 at the focus position, the measurement laser as in the previous reference value setting step (S602) by reflecting the beam (L1) from the object (10), the image (I ₁ 'for the two split beams spaced from each other a distance (d _r) as shown in Figure 11 haebomyeon sensing a second image from the image sensor, I ₂ ') can be identified.

However, since the object 10 cannot have the same size or thickness as the specimen 11 for measurement, the surface of the object 10 is out of focus. For example, the object to be processed 10 is fixed to the first stage while the first stage that has fixed the specimen 11 for measurement at the focus position is fixed to the first stage, if the object 10 is the specimen for measurement 11 If the thickness is thicker than ), the surface of the object 10 in FIG. 10 is moved in the (-)z-axis direction rather than the focus position to be positioned.

In this case, the measurement laser beam L1 in the form of two split beams reflected from the surface of the object to be processed 10 is compared with the first image at the focus position detected in the previous reference value setting step S602, the image sensor The separation distance d _r between the images I ₁ ′ and I ₂ ′ for the two split beams in the second image detected in FIG.

At this time, a set value that is a separation distance (d _f , see FIG. 4) in the first image and a measured value that is a separation distance (d _r ) in the second image are compared to match the measured value to the set value. . To this end, by moving the position of the object 10 to be processed and fixing the position of the object 10 to be processed at a position where the measured value coincides with the set value, the object 10 is positioned at the focus position. For example, through the position adjustment step S603, the surface of the object to be processed 10 is positioned at the focus position.

Thereafter, through the processing step, as shown in FIG. 13, the surface of the object 10 located at the focus position is processed with a laser beam L2 for processing, and the surface of the object 10 is positioned at the correct focus position. Therefore, very precise processing is possible.

On the other hand, as shown in FIG. 11, when the measured value dr is large, the image measurement range may be out of the range. In this case, by adjusting the position of the image sensor 190, the measurement range may be extended.

For example, as shown in FIG. 10, the position of the image I1 ′ of the split beam located at the center of the image may be moved to the edge of the image as shown in FIG. 12 to extend the measurement range of the measured value dr. In this case, the image sensor 190 can be horizontally moved on the xy plane in FIG. 10, and for example, by moving the second stage on which the image sensor 190 is mounted on the xy plane, measurement as in FIG. 12 described above. You can expand the scope.

As described above, the laser processing apparatus 100 according to an embodiment of the present invention includes a focus measurement module including a measurement laser light source that emits a measurement laser beam L1, so that the laser beam for processing ( It is possible to find out the exact focus position of L2). In addition, by using the mask 150 having two through holes provided in the focus measurement module, the measuring laser beam L1 can be transformed into two split beams, through which the processing laser beam L2 is Focus position can be measured easily and precisely.

In addition, in the laser processing method according to an embodiment of the present invention, by moving the object 10 to be positioned at the focus position of the laser beam L2 for processing, and then performing the processing, the object to be processed can be processed more precisely. have. In addition, by adjusting the divergence angle of the measurement laser beam L1 through the light divergence unit 170, the measurement resolution of the image detected by the image sensor 190 may be adjusted. In addition, by adjusting the position of the image sensor 190, the measurement range of the image can be adjusted.

Although the preferred embodiments of the present invention have been described through the above, the present invention is not limited thereto, and it is possible to carry out various modifications within the scope of the claims and detailed description of the invention and the accompanying drawings. Naturally, it is within the scope of the invention.

10 Object to be processed 11 Specimen for measurement
100 Laser processing unit 110 Measuring laser light source
120 Processing laser light source 131 1st light focusing unit
132 Second light focusing unit 141 First beam splitter
142 2nd beam splitter 150 mask
170 light emission part 180 light filter
190 image sensor

Claims (14)

Processing laser light source;
A first beam splitter disposed in the path of the processing laser beam emitted from the processing laser light source;
A first light focusing unit focusing the processing laser beam transmitted through the first beam splitter onto an object to be processed; And
A focus measurement module configured to detect an image of light reflected from the object to be processed and measure a focus position of the laser beam for processing;
Including,
The focus measurement module,
A measurement laser light source for emitting a measurement laser beam to be reflected from the object to be processed;
A mask disposed on a path of the measuring laser beam toward the object to be processed, and blocking a part of the measuring laser beam to transform a single beam shape into two split beam shapes; And
An image sensor that passes through the mask and detects an image of the two split beams reflected from the object to be processed;
It includes,
A first through hole and a second through hole penetrating the mask along the traveling direction of the measuring laser beam are formed in the mask,
The first through-hole is disposed in the center based on the cross-section of the measuring laser beam, and the second through-hole is disposed to be spaced apart from the first through-hole by a predetermined distance within the cross-section of the measuring laser beam. Processing device. delete The method of claim 1,
The focus measurement module,
A second beam splitter disposed in a path of the measuring laser beam passing through the mask;
A second light focusing unit disposed between the second beam splitter and the image sensor;
It further includes,
The first beam splitter is disposed so that the measuring laser beam reflected from the object to be processed is incident and reflected toward the second beam splitter,
The second beam splitter is disposed so that the measuring laser beam reflected from the first beam splitter is incident and reflected toward the image sensor. The method of claim 1,
A control unit for adjusting a position of the object to be processed so that a distance value between the two split beams becomes a set reference value in the image detected by the image sensor;
The laser processing apparatus further comprising a. The method of claim 3,
The focus measurement module,
A light diffusion unit disposed between the measurement laser light source and the mask to adjust a divergence angle of the measurement laser beam;
The laser processing apparatus further comprising a. The method of claim 5,
The light diverging part
A laser processing apparatus comprising a first lens to emit light, and a second lens to focus light. The method of claim 4,
Further comprising a stage for supporting the object to be processed,
The stage is moved along a direction in which the processing laser beam travels by the control unit. The method of claim 3,
The focus measurement module,
An optical filter disposed between the second beam splitter and the second optical focusing unit to pass only the measurement laser beam;
The laser processing apparatus further comprising a. As a laser processing method using the laser processing device according to claim 1,
Placing a specimen for measurement in place of the object to be processed to find a focus position of the laser beam for processing;
Setting a measurement value in the reflected image as a reference value by irradiating the measurement laser beam onto the measurement specimen positioned at the focus position;
Arranging the object to be processed in place of the specimen for measurement, and irradiating the laser beam for measurement to the object to adjust the position of the object to be processed so that the measured value in the reflected image matches the reference value; And
Processing the object to be processed by irradiating the laser beam for processing;
Containing, laser processing method. The method of claim 9,
The step of finding the focus position,
While moving the measurement specimen along the traveling direction of the processing laser beam, finding a point where the line width processed on the measurement specimen becomes the minimum value. The method of claim 9,
In the mask
A first through hole disposed in the center based on the cross-section of the measuring laser beam, and a second through hole disposed at a predetermined distance apart from the first through hole within the cross-section,
The step of setting as the reference value,
Transforming the single beam shape into the two split beam shapes and irradiating the measurement specimen at the focus position;
Sensing, by the image sensor, a first image of two split beams reflected from the measurement specimen; And
Setting a first measurement value obtained by measuring a distance between the two split beams in the first image as a reference value;
Containing, laser processing method. The method of claim 11,
In the irradiating step, adjusting a divergence angle of the measuring laser beam. The method of claim 11,
Adjusting the position of the object to be processed,
Placing the object to be processed instead of the specimen for measurement;
Transforming the measuring laser beam into the two split beams and irradiating the object to be processed;
Sensing, by the image sensor, second images of two split beams reflected from the object to be processed;
Comparing a second measurement value obtained by measuring a distance between the two split beams in the second image with the reference value; And
Adjusting the position of the object to be processed so that the second measured value matches the reference value;
Containing, laser processing method. The method of claim 13,
In the step of detecting the second image by the image sensor, the position of the image sensor is adjusted.

Images