KR20200001968A - Laser dicing device for suppressing scattering - Google Patents

Abstract

The present invention relates to a laser cutting apparatus for suppressing scattering. The laser cutting apparatus for suppressing scattering according to an embodiment of the present invention comprises: a Gaussian laser light irradiation part; an optical modulation part modulating a shape of Gaussian laser light by reducing the intensity of irradiated Gaussian laser light around the direction parallel to a laser processing direction of the irradiated Gaussian laser light; a condensing lens part condensing the modulated laser light; and a semiconductor substrate mounting part to be mounted with a semiconductor substrate to be cut, wherein the modulated laser light is focused inside the semiconductor substrate mounted on the semiconductor substrate mounting part.

Description

Laser dicing device for suppressing scattering

The technical idea of the present disclosure relates to a laser device for cutting, and more particularly, to a cutting laser device that suppresses scattering of laser light in a substrate to prevent optical damage of a semiconductor element formed in the substrate.

Conventionally, in order to divide the board | substrate with which the semiconductor device, the electronic component, etc. were formed into individual chips, the cutting device which cuts the board | substrate by putting the thin cutting blade in which the fine diamond was formed into the grinding groove of the board | substrate was cut. In the case of a substrate cutting process by a conventional cutting blade, chipping occurs on the surface or the back surface of the substrate, and this chipping has become a factor that degrades the performance of the divided chips.

Due to this problem, instead of cutting by a conventional cutting blade, a laser light having a focusing point is incident on the inside of the substrate, and modified regions and cracks are formed inside the substrate by multiphoton absorption to divide the chips into individual chips. A laser device for cutting has been proposed.

The first problem to be solved by the technical idea of the present disclosure is to provide a laser light modulation method for preventing the scattering of the laser light incident on the substrate because the laser light focused on the inside of the substrate does not spatially overlap with the previously formed modified region and cracks will be.

The second problem to be solved by the technical idea of the present disclosure is to provide a laser device for cutting to prevent scattering of the laser light incident on the substrate because the laser light focused on the inside of the substrate does not spatially overlap with the previously formed modified region and cracks will be.

A third problem to be solved by the technical idea of the present disclosure is to provide a substrate cutting method for preventing scattering of laser light incident on the substrate because the laser light focused on the inside of the substrate does not spatially overlap with the previously formed modified region and cracks. .

An emission step of emitting a Gaussian laser light according to an embodiment of the present disclosure to achieve the above object; And a modulating step of modulating the shape of the Gaussian laser light by reducing the intensity in the vicinity of a direction parallel to the processing direction of the Gaussian laser light emitted in the emitting step.

Another embodiment of the present disclosure is a Gaussian laser light emitting unit; An optical modulator for modulating the shape of the Gaussian laser light by reducing an intensity in the vicinity of a direction parallel to the laser processing direction of the emitted Gaussian laser light; A condenser lens unit for condensing the modulated laser light; And a semiconductor substrate mounting portion on which the semiconductor substrate to be cut is to be mounted, wherein the modulated laser light is focused to the inside of the semiconductor substrate seated on the semiconductor substrate mounting portion. .

In another embodiment of the present disclosure, a light emitting step of emitting a Gaussian laser light; A light modulation step of modulating the shape of the Gaussian laser light by reducing the intensity in the vicinity of the direction parallel to the laser processing direction of the emitted Gaussian laser light; A light condensing step of condensing the modulated laser light; A crack forming step of focusing the focused laser light into a substrate to form a modified region and a crack; An apparatus driving step for relatively moving the laser apparatus and the substrate in a cutting direction; And a cutting step of cutting the substrate individually by expanding the formed crack by applying an external force to the substrate.

Cutting laser device according to the technical idea of the present disclosure modulates the shape of the Gaussian laser light by reducing the intensity of the vicinity of the direction parallel to the laser processing direction of the Gaussian laser light, the modulated laser light is incident on the substrate As a result, the spatial overlap between the modulated laser light focused in the substrate and the preformed modified regions and cracks can be minimized. Therefore, since laser light is not scattered in the substrate, optical damage of the semiconductor device formed in the substrate may be prevented, and flexibility of the cutting process of the semiconductor substrate may be increased.

1A to 1C are conceptual views illustrating that laser light emitted from a cutting laser device is focused near a light collection point inside a substrate to form a modified region and a crack.
2A and 2B are conceptual views illustrating that laser light emitted from a conventional cutting laser device is focused near a light collecting point inside a substrate to form a modified region and a crack.
3A and 3B are conceptual views illustrating that laser light emitted from a cutting laser device according to an exemplary embodiment of the present disclosure is focused near a focusing point inside a substrate to form a modified region and a crack.
4A and 4B are diagrams and graphs illustrating the shape and intensity of a Gaussian laser light according to an exemplary embodiment of the present disclosure.
4C-4E illustrate shapes of an 8-shaped laser light in accordance with exemplary embodiments of the present disclosure.
4F is a graph showing the intensity of light according to the azimuth angle of the 8-shaped laser light shown in FIG. 4E according to an embodiment of the present disclosure.
4G-4I illustrate shapes of modulated laser light according to exemplary embodiments of the present disclosure.
5 is a diagram illustrating a laser light modulator for modulating a Gaussian laser light into an 8-shaped laser light according to an exemplary embodiment of the present disclosure.
6A to 6D are diagrams illustrating a laser light modulator using a slit according to an exemplary embodiment of the present disclosure.
7 is a diagram illustrating a laser light modulator using a spatial light modulator according to an exemplary embodiment of the present disclosure.
8 is a view illustrating a laser light modulator using a birefringent lens according to an exemplary embodiment of the present disclosure.
9 is a view showing a modulation aspect of the laser light according to FIG. 8 according to an exemplary embodiment of the present disclosure.
10 is a diagram illustrating the shapes of radial and azimuth CVBs in accordance with an exemplary embodiment of the present disclosure and a graph showing the intensity of light in the CVBs.
FIG. 11 is a diagram illustrating a laser light modulator for modulating Gaussian laser light into CVB and then modulating back into 8-shaped laser light according to an exemplary embodiment of the present disclosure.
12 illustrates CVB modulation using a spiral element according to an exemplary embodiment of the present disclosure.
13 illustrates CVB modulation using multiple spatial light modulators in accordance with an exemplary embodiment of the present disclosure.
14 illustrates CVB modulation using an optical fiber polarization controller according to an exemplary embodiment of the present disclosure.
15 illustrates CVB modulation using a spatially divided half-wave plate according to an exemplary embodiment of the present disclosure.
16 is a diagram illustrating a polarization filter as an example of an eight-shaped light modulation module according to an exemplary embodiment of the present disclosure.
17A is a diagram illustrating a shape in which a radial CVB is modulated into 8-shaped light by a vertical polarization filter according to an exemplary embodiment of the present disclosure.
FIG. 17B is a diagram illustrating a shape in which azimuth CVB is modulated into 8-shaped light by a horizontal polarization filter according to an exemplary embodiment of the present disclosure.
18 is a graph showing intensity according to angles of CVB and 8-shaped light according to an exemplary embodiment of the present disclosure.
19 is a configuration diagram showing an outline of cutting processing of a cutting laser device according to an exemplary embodiment of the present disclosure.
20 is a configuration diagram illustrating an outline of distance measurement of a cutting laser device according to an exemplary embodiment of the present disclosure.
21 is a diagram illustrating division into individual semiconductor substrates through an external force according to an exemplary embodiment of the present disclosure.
22 is a flowchart illustrating a flow of a method of cutting a semiconductor substrate and a flow of an optical modulation method, according to an exemplary embodiment of the present disclosure.
23 is a flowchart illustrating a flow of a method of cutting a semiconductor substrate and a flow of a distance measurement according to an exemplary embodiment of the present disclosure.

FIG. 1A is a side of the substrate S illustrating the formation of the modified region P and the crack C by concentrating the laser light L1 emitted from the cutting laser device near the condensing point inside the substrate S. FIG. It is a cross section.

Referring to FIG. 1A, the laser light L1 of the cutting laser device that has passed through the surface of the substrate S concentrates energy in the vicinity of the focusing point. The laser light L1 condensed near the condensing point in the substrate S may form a modified region P and a crack C. FIG.

The cutting laser device may be a stealth dicing (SD) laser device. The stealth dicing laser device may focus a laser beam for cutting at a wavelength that may penetrate the semiconductor substrate by a lens to focus at a point inside the semiconductor substrate. The focused cutting laser light may be composed of short pulses oscillating at a high repetition rate, and the cutting laser light may be highly condensed to a critical level of diffraction. In the substrate, the cutting laser light may be focused at a very high peak power density near the focusing point and may be spatially compressed. When the cutting laser light passing through the semiconductor substrate is condensed, when the peak power density is exceeded, an extremely high nonlinear multiphoton absorption phenomenon may occur near the light collecting point. Due to the high nonlinear multi-photon absorption phenomenon occurring near the light collection point, the crystal of the substrate S absorbs the energy of the light condensed in the substrate S, causing thermal melting, resulting in a modified region P and cracks. (C) can be formed. The stealth dicing laser device can be used to selectively process only local points within the substrate without damaging the front and rear surfaces of the semiconductor substrate. The cutting laser device may also include a mechanism for moving the relative position of the laser light and the substrate to cut the substrate at high speed according to the cutting pattern.

FIG. 1B shows that after the laser device forms the modified region P and the crack C at a portion of the substrate S, the laser apparatus moves relatively in the processing direction so that the plurality of modified regions P, P, ...) and the side cross-sectional view of the board | substrate S which conceptually shows the state which formed the crack C, C, .... By forming the plurality of modified regions P and the cracks C, the balance of the intermolecular force may be destroyed in the substrate S. When the external force is applied to the substrate S, the substrate S may be modified region ( It can be naturally divided based on P) and crack (C).

FIG. 1C is a side sectional view of the substrate S showing a state in which the modified region P and the crack C are formed in multiple layers inside the substrate S. FIG. By adjusting the location of the light collecting point of the laser light L1, the modified region P and the crack C may be formed at various heights in the substrate S. FIG. Due to the modified region P and the crack C of various heights, flexibility of the cutting process of the substrate S may be increased.

2A and 2B show a state in which the laser light L2 emitted from the conventional cutting laser device forms the modified region P and the crack C in the semiconductor substrate. Specifically, FIG. 2A is a side cross-sectional view of the substrate S illustrating the conventional laser light L2 focusing near the condensing point inside the substrate S to form the modified region P and the crack C. FIG. FIG. 2B is a plan view of the substrate S illustrating that the conventional laser light L2 is focused near the condensing point inside the substrate S to form the modified region P and the crack C. FIG.

2A and 2B, a spatial overlap D may occur between the laser light L2 emitted from the conventional cutting laser device and the preformed modified region P and / or the crack C. FIG. . Due to the spatial overlap D, a part of the laser light L2 incident into the substrate may be scattered in the semiconductor substrate S, and the scattered light L2 'is a semiconductor device formed in the semiconductor substrate S. Can cause optical damage. In addition, in the conventional cutting laser device, when the laser light L2 is closely incident to improve the cutting force of the semiconductor substrate S, the space between the laser light L2 and the preformed modified region P and / or the crack C may be reduced. There is a risk that the damage of the substrate due to scattering of the laser light L2 is increased by increasing the overlap D. Embodiments of the present disclosure described below may solve the above problems of the conventional cutting laser device.

3A and 3B illustrate a state in which the laser light L3 emitted from the cutting laser device according to the embodiment of the present disclosure forms the modified region P and the crack C in the semiconductor substrate. Specifically, FIG. 3A illustrates that the cutting laser light L3 according to an embodiment of the present disclosure is focused near the light collecting point inside the substrate S to form the modified region P and the crack C. FIG. 3 is a side cross-sectional view of the substrate S, and FIG. 3B is a plan view of the substrate S according to the embodiment of the present disclosure.

3A and 3B, unlike the conventional cutting laser device, the laser light L3 emitted from the cutting laser device of the present disclosure and incident on the substrate S is viewed from above when viewed from above. The light may be absent in the vicinity of the direction parallel to the direction. Substantially, light may be absent in a direction parallel to the processing direction of the laser light L3. However, the present invention is not limited thereto, and the light may exist at a relatively weak intensity in the vicinity of the direction parallel to the processing direction of the laser light L3 than the light in the vicinity of the direction perpendicular to the processing direction.

In one embodiment, the laser light L3 incident on the substrate S may have an 8-shaped shape in which light is absent in the vicinity of a direction parallel to the laser processing direction when viewed from above. . Due to the shape of the absence of light in the vicinity of the direction parallel to the processing direction of the cutting laser light L3, spatial overlap between the preformed modified region P and the crack C and the laser light L3 is prevented. Can be prevented or minimized. Therefore, it is possible to prevent or reduce the scattering of the laser light (L3) to prevent optical damage of the semiconductor elements formed on the semiconductor substrate (S).

In the following description of the invention, a method of reducing the intensity of light in the vicinity of a direction parallel to the processing direction of the laser light, for example, a method of modulating the laser light into an 8-shaped laser light will be described in more detail. do. 4A and 4B illustrate the shape and intensity of the laser light in a Gaussian distribution. FIG. 4A shows the shape of a circular Gaussian laser light, and FIG. 4B is a graph showing the intensity distribution of the laser light along an arbitrary diameter of the Gaussian laser light of FIG. 4A.

The Gaussian distribution means a distribution in which the frequency distribution curve is symmetrical about the mean value. Referring to the graph of FIG. 4B, the intensity of the circular Gaussian laser light is symmetrical, is the strongest in the center, and weakens the farther from the center. In addition, the Gaussian laser light may have a spatially homogeneous polarization (eg, linear or circular).

The present disclosure discloses that the circular Gaussian laser light (FIG. 4A) is absent in the vicinity of the direction parallel to the laser processing direction in order to prevent or reduce scattering of laser light in the semiconductor substrate to protect semiconductor devices formed in the semiconductor substrate. The light may be modulated into a shape of light and incident on the substrate.

4C to 4I illustrate modulated laser light in a shape without light in the vicinity of a direction parallel to a laser processing direction according to an embodiment of the present disclosure.

4C-4E, the shape of the modulated laser light incident on the substrate in accordance with one embodiment of the present disclosure may be eight-shaped. Although the 8-shaped laser lights shown in FIGS. 4C to 4E may differ in shape from each other, in general, there is no light or intensity of light in the vicinity of a direction parallel to the laser processing direction at the center of the light. It may be relatively weak, and the intensity of light in the vicinity of the direction perpendicular to the laser processing direction at the center of the light may be counted relative to the light in the vicinity of the direction parallel to the laser processing direction. The following describes the shape and characteristics of 8-shaped laser lights in more detail.

Referring to FIG. 4C, in some embodiments of the present invention, the 8-shaped laser light L4c may be shaped generally in the shape of an hourglass. The eight-shaped laser light L4c may be absent or relatively weak in intensity near the direction parallel to the laser processing direction at the center of the light. However, the intensity of light in the vicinity of the direction perpendicular to the laser machining direction at the center of the light can be counted relative to the light in the vicinity of the direction parallel to the laser machining direction at the center of the light.

The hourglass-shaped eight-shaped laser light L4c draws a straight line c passing through the center of the light in a direction perpendicular to the laser processing direction. As the distance near the center of the light along the straight line c, the intensity of the light may be weakened. In addition, the intensity of the hourglass-shaped eight-shaped laser light L4c may be uniform along the straight line c. The hourglass-shaped eight-shaped laser light L4c may have polarization that is not symmetrical with respect to the central axis. The hourglass shaped eight-shaped laser light L4c may be made by modulating a Gaussian laser light through an optical modulation module such as a slit, a spatial light modulator, and the like. When the Gaussian laser light is modulated by the 8-type laser light L4c through the slit, the intensity of the light can be counted in the vicinity of the center, and the Gaussian laser light is 8-type laser light through the spatial light modulator. In the case of modulation with L4c), the intensity of light may be counted near the center, and the intensity may be uniform along the straight line c.

Referring to FIG. 4D, the illustrated 8-shaped laser light L4d may have a shape in which the light is empty in a part of the hourglass shape that is spaced apart from the center by a predetermined distance d. The eight-shaped laser light L4d may be absent or weak from the center of the light to a portion away from the center by a predetermined distance d. In addition, the eight-shaped laser light L4d may be absent or relatively weak in intensity near the direction parallel to the laser processing direction at the center of the light. However, the intensity of light in the vicinity of the direction perpendicular to the laser machining direction at the center of the light can be counted relative to the light in the vicinity of the direction parallel to the laser machining direction at the center of the light.

The 8-shaped laser light L4d of FIG. 4D may be made by modulating a Gaussian laser light through a combination of a birefringent lens and a slit described later.

Referring to FIG. 4E, the portion of the illustrated 8-shaped laser light L4e spaced apart by the first distance t from the center in the shape of the hourglass may be an empty shape. As shown in FIG. 4E, the light is different in the ring-shaped region R farther from the center than the first distance t and closer than the second distance t 'according to the 360 degree rotation of the azimuth angle theta. May exist in strength. The intensity of light in the ring-shaped region R is relatively high in the vicinity where the azimuth angle is 90 degrees or 270 degrees (ie, in the vicinity of the direction perpendicular to the laser processing direction at the center of the light), and the azimuth angle is 0 degrees, 180 degrees. It may be relatively weak in the vicinity of the island (ie near the direction parallel to the laser processing direction at the center of the light).

FIG. 4F shows a graph of the intensity of light in a ring-shaped region R with a 360 degree rotation of the azimuth angle Θ of the 8-shaped laser light L4e shown in FIG. 4E. . Referring to FIG. 4F, the intensity of light in the ring-shaped region R may form an absolute value sine curve according to the rotation of the azimuth. When the azimuth angle is 90 degrees or 270 degrees, the intensity of the laser light has a maximum value M, and when the azimuth angle is 0 degrees or 180 degrees, the laser light may be absent. In the graph of FIG. 4F, 1 / SQRT (2) (SQRT (A) represents the square root of A.) of the maximum value M of the intensity of the 8-shaped laser light L4e. The part which has the light intensity of the following is shown with the hatched. More specifically, referring to FIG. 4F, the intensity of the 8-shaped laser light L4e in the section where the azimuth angle is 45 degrees to 135 degrees and 225 degrees to 315 degrees is 1 / SQRT (the maximum value M). 2) It may have an intensity less than or equal to the maximum value (M).

Laser processing of substrate cutting in which the intensity of light at a portion (i.e., 45 degrees to 135 degrees and 225 degrees to 315 degrees) having an intensity greater than or equal to 1 / SQRT (2) of the maximum value M or less is less than or equal to the maximum value M Can be the main light intensity. Therefore, if the light of the portion having the intensity of 1 / SQRT (2) or more than the maximum value (M) of the maximum value (M) can be represented by the shape (L4e) of the 8-shaped laser light of Figure 4e.

The 8-shaped laser light of FIG. 4E may be formed by modulating a ring-shaped cylindrical vector beam (CVB) having polarization symmetrical about a central axis while passing through a polarization filter. Is described in detail later.

The 8-shaped laser light shown in FIGS. 4C to 4F focuses the light in the semiconductor substrate and cuts the substrate, wherein the 8-side side portion having no light or the light intensity is relatively low. The upper and lower portions of the eight characters which are in contact with the cutting process line of the image and having a relatively strong light intensity may be spaced apart from the cutting process line on the substrate. Accordingly, the cutting 8-shaped laser light incident in the substrate and relatively moved in the cutting processing direction does not overlap with the pre-formed modified regions and cracks so that it is not scattered in the substrate so that the optical elements of the semiconductor elements formed inside the substrate are not scattered. Damage can be prevented.

4G-4I illustrate shapes of modulated laser light according to an exemplary embodiment of the present disclosure. The modulated laser lights described with reference to FIGS. 4G to 4I are different in shape from the eight-shaped laser lights described with reference to FIGS. 4C to 4F, but the light is absent in the vicinity of the direction parallel to the laser processing direction. The light intensity is similar to the aforementioned eight-type laser light in that the light is weak.

Referring to FIG. 4G, the modulated laser light L4g of the present disclosure may have a shape in which the light is absent from a circular laser light to a portion vertically spaced apart by a predetermined distance f from a processing line passing through the center of the circle. have.

The modulated laser light L4g of FIG. 4G may be made while circular Gaussian laser light passes through a slit (601b in FIG. 6B) which will be described later. When the Gaussian laser light is modulated with the modulated laser light L4g through the slit 601b, the intensity of the modulated laser light L4g can be counted relatively near the center and relatively near the edge. May be weak.

Referring to FIG. 4H, the modulated laser light L4h of the present disclosure has a shape in which the light is absent up to a portion spaced vertically by a predetermined distance f from the processing line passing through the center of the circle in the circular laser light. Can be.

More specifically, when a straight line c passing through the center of the modulated laser light L4h in a direction perpendicular to the laser processing direction at the center of the modulated laser light L4h is drawn, the straight line c is referred to. As a result, the light L4h in the direction opposite to the laser processing direction may be absent or weakly intensified to a portion spaced apart from the processing line vertically by a predetermined distance f. The light L4h in the laser processing direction of the modulated laser light L4h based on the straight line c may have an incomplete semicircular shape because light is not modulated. The modulated laser light L4h of FIG. 4H may be made while circular laser light passes through the slit 601c of FIG. 6C to be described later. When the Gaussian laser light is modulated with the modulated laser light L4h through the slit 601b, the intensity of the modulated laser light L4h can be counted relatively near the center and relatively weak near the edge. Can be.

Referring to FIG. 4I, the modulated laser light L4i may have a shape in which light is absent at a portion formed by an azimuth angle θ that rotates with respect to the center of the circular laser light.

More specifically, when a straight line c passing through the center of the modulated laser light L4i in a direction perpendicular to the laser processing direction at the center of the modulated laser light L4i is drawn, the straight line c is referred to. As a result, the light L4i in the direction opposite to the laser processing direction may be absent or the intensity of the light may be absent at the fan-shaped portion formed by the azimuth angle Θ. The light L4i in the laser processing direction of the modulated laser light L4i based on the straight line c may have an incomplete semicircular shape because light is not modulated.

The azimuth angle Θ may be about 30 degrees to about 60 degrees with respect to the processing line. More specifically, the azimuth angle Θ may be about 45 degrees with respect to the processing line.

The modulated laser light (L4g, L4h, L4i) according to FIGS. 4G-4I may be absent or relatively weak in intensity in the vicinity of the direction parallel to the laser processing direction and perpendicular to the laser processing direction at the center of the light. The intensity of light in the vicinity of the phosphorus direction can be counted relative to the light in the vicinity of the direction parallel to the laser processing direction. Accordingly, the modulated laser light L4g, L4h, L4i incident in the substrate and relatively moved in the cutting direction does not overlap with the previously formed modified regions and cracks and thus does not scatter in the substrate, thereby forming a semiconductor device formed inside the substrate. Can prevent their optical damage.

FIG. 5 is a diagram illustrating a laser light modulator 500 for modulating a shape of a Gaussian laser light by reducing an intensity in the vicinity of a direction parallel to a laser processing direction of a Gaussian laser light according to an exemplary embodiment of the present disclosure. to be.

Referring to FIG. 5, in one embodiment, the Gaussian laser light L5 emitted from the laser light emitter 50 is an eight-shaped laser light L5 ′ through the laser light modulator 500. Can be modulated by When the modulated 8-shaped laser light L5 'is incident on the substrate, the incident 8-shaped laser light L5' does not spatially overlap with the previously formed modified regions and cracks as described above. The scattering of the light L5 ′ in the substrate may be prevented to prevent optical damage of the semiconductor devices formed in the substrate.

Hereinafter, a method of modulating a Gaussian laser light into laser light having a relatively low intensity of light in the vicinity of a direction parallel to the laser processing direction will be described in detail as embodiments of the present disclosure.

6A to 6D are diagrams illustrating a laser light modulator 600 using slits according to exemplary embodiments of the present disclosure, respectively.

Referring to FIG. 6A, the laser light modulator 600 uses an slit 601a to convert an Gaussian laser light L6 emitted from the laser light emitter 60 into an eight-shaped laser. Modulation can be made with light L6a '.

The slit 601a refers to a device for restricting and passing light. The slit 601a, which is an embodiment of the laser light modulator 600, may block a portion of the Gaussian laser light L6 without passing the other portion of the Gaussian laser light L6.

As shown in Figure 6a, the slit 601a may be formed in the shape of an eight-shaped or infinity (∞) rotated 90 degrees. In addition, the slit 601a may be formed of a plurality of slits. The side portion of the Gaussian laser light L6 emitted from the laser light output unit 60 may be blocked by the slit 601a, and the upper and lower portions of the Gaussian laser light L6 are the slit 601a. May not block the light beam. Thus, a portion of the Gaussian laser light L6 is blocked by the slit 601a so that the Gaussian laser light L6 may be modulated into an 8-shaped laser light L6a '. Since the modulated 8-shaped laser light L6a 'has no change in the optical mode of the Gaussian laser light L6, like the Gaussian laser light, the intensity of light is relatively high at the center and relative to the side. May be weak.

6B to 6D, the slits 601b to 601d, which are embodiments of the present disclosure, may have various shapes, thereby allowing the Gaussian laser light L6 to be in the vicinity of a direction parallel to the laser processing direction. The light can be modulated into light L6b 'and L6c' L6d 'having various shapes. Referring to FIG. 6B, the slit 601b has a plate shape in which two semicircular cavities are formed at the top and the bottom thereof. Can be. More specifically, the semicircular cavities may be formed as an upper semicircle cavity and a lower semicircle cavity by a lane that transverses the center of the circle in a circular cavity.

The circular Gaussian laser light L6 emitted from the laser light output part 60 has a shape in which the light is absent from the line passing horizontally through the center of the circle horizontally by a slit 601b to a portion spaced vertically by a predetermined distance. Can be modulated with the laser light L6b '. Since the modulated laser light L6b 'has no change in the optical mode of the Gaussian laser light L6, like the Gaussian laser light L6, the light intensity may be relatively strong at the center and relatively weak at the side. .

The modulated laser light L6b 'may have substantially the same technical details as those described with reference to FIG. 4G. Thus, the modulated laser light L6b 'may be absent or relatively weak in intensity in the vicinity of the direction parallel to the laser processing direction. Therefore, the modulated laser light L6b 'does not overlap with the modified regions and cracks previously formed in the substrate, so that the modulated laser light L6b' is not scattered in the substrate, thereby preventing optical damage of the semiconductor devices formed in the substrate.

Referring to FIG. 6C, the cavity of the slit 601c may be formed by a lane extending horizontally from the edge of the circle to the center in the circular cavity.

The circular Gaussian laser light L6 emitted from the laser light output unit 60 has no light to a predetermined portion vertically spaced apart from the processing line passing horizontally through the center of the circle by the slit 601c. It can be modulated by the laser light (L6c ') of the shape. More specifically, the modulated laser light L6c 'in a direction opposite to the laser processing direction with respect to the center of the modulated laser light L6c' is light up to a portion vertically spaced apart from the processing line. It may be absent or the light intensity may be weak. The modulated laser light L6'c in the laser processing direction based on the center of the modulated laser light L6c 'may have an incomplete semicircular shape since light is not modulated.

The modulated laser light L6c ′ may have substantially the same technical details as those described with reference to FIG. 4H. Since the modulated laser light L6c 'has no change in the optical mode of the Gaussian laser light L6, the light intensity may be relatively strong at the center and relatively weak at the side like the Gaussian laser light L6. Accordingly, the modulated laser light L6′c may not overlap with the modified regions and cracks previously formed in the substrate and thus may not be scattered in the substrate, thereby preventing optical damage of the semiconductor elements formed in the substrate.

Referring to FIG. 6D, the cavity of the slit 601d may be formed by a fan-shaped plate formed in a direction opposite to the machining direction with respect to the center of the circle in the circular cavity.

The circular Gaussian laser light L6 emitted from the laser light output unit 60 may be modulated by the slit 601d into laser light L6d 'having no light in the sector. .

The modulated laser light L6d 'in the direction opposite to the laser processing direction may be absent or relatively weak in intensity in the sector shape. The modulated laser light L6d ′ in the laser processing direction may be in an intact semicircular shape because light is not modulated.

The modulated laser light L6d 'may have substantially the same technical details as those described with reference to FIG. 4I. The modulated laser light L6'd may be absent or relatively weak in intensity at a predetermined vicinity in a direction parallel to the laser processing direction. Therefore, the modulated laser light L6'd may not overlap with the modified regions and cracks formed in the substrate and may not be scattered in the substrate, thereby preventing optical damage of the semiconductor devices formed in the substrate.

7 illustrates a laser light modulator 700 using a spatial light modulator (SLM) according to an exemplary embodiment of the present disclosure. Referring to FIG. 7, the laser light modulator 700 may modulate the shape of the Gaussian laser light L7 using a spatial light modulator (SLM) 701. More specifically, the spatial light modulator 701 may modulate the shape of the Gaussian laser light L7 by reducing the intensity of the Gaussian laser light L7 in the vicinity of the direction parallel to the laser processing direction. In one embodiment, the spatial light modulator 701 may modulate the Gaussian laser light L7 into an 8-shaped laser light L7 '.

The spatial light modulator 701 is a device that modulates incident light incident from the light source into the spatial light modulator 701 into an external electric signal to change and output light information. The spatial light modulator 701 may modulate the intensity of the circular circular Gaussian laser light L7 by controlling the rotation direction of the polarization plane of the light incident on the medium by changing the voltage.

In addition, the spatial light modulator 701 is composed of a plurality of pixels (pixels, 702), the spatial light modulator 701 is a circular Gaussian laser input for each pixel (702) by the voltage applied from the outside The intensity and phase of the light L7 can be modulated.

Accordingly, the Gaussian laser light L7 emitted from the laser light output part 70 may be in a direction parallel to the laser processing direction by the intensity and phase change of each pixel (pixel) 702 of the spatial light modulator 701. Nearby light can be modulated into an absent shape, for example an 8-shaped laser light L7 '. At this time, unlike when the slit 601 is used, the modulation of the intensity and phase of light is possible for each pixel in the spatial light modulator 701, so that the modulated eight-character (8-) shaped) The intensity of the center portion of the laser light L7 'may be relatively strong and the intensity of the side portions may be relatively weak, and the intensity may be even throughout. Compared to using the slits 601a to 601d of FIGS. 6A to 6D, the spatial light modulator 701 of FIG. 7 can freely adjust the intensity and phase of incident light.

8 is a diagram illustrating a laser light modulator 800 using a birefringent lens according to an exemplary embodiment of the present disclosure. 9 is a view showing a modulation aspect of the laser light according to FIG. 8 according to an exemplary embodiment of the present disclosure.

Referring to FIG. 8, the laser light modulator 800 uses a birefringent lens 801, an objective lens 802, and a plurality of slits 803 and 804 to perform circular Gaussian laser light L8. It can be modulated with an 8-shaped laser light (FIG. 9C).

The laser light modulator 800 of FIG. 8 includes a birefringent lens 801, an objective lens 802, a center slit 803, and a side slit 804. The birefringent lens 801 may be configured by combining a glass body 81 having a concave surface 81a and a crystal body 82 having a convex surface 82a. The birefringent lens 801 separates the circular Gaussian laser light L8 into the first split light L8 'indicated by the solid line and the second split light L8' indicated by the dotted line. The first split light L8 'is linearly polarized light in which the vibration direction is orthogonal to the machining progress direction, and the second split light L8 " is linearly polarized light in which the vibration direction is parallel to the machining progress direction. The birefringent lens 801 passes through the first split light L8 'without refracting, and passes the second split light L8' to the outside by refracting the crystal 82.

8 and 9, when the circular Gaussian laser light L8 passes through the birefringent lens 801, the laser is shaped into a shape with a small circle in the circular ring in cross section a of FIG. 8 (FIG. 9A). Light can be modulated.

The objective lens 802 of FIG. 8 serves to condense the separated lights L8 ′, L8 ″ separated by the birefringent lens 801. The split light L8 ″ refracted through the birefringent lens 801 may form a condensing point at a position deeper than the split light L8 ′ which is not refracted and passed through as it is.

Separation lights L8 ′ and L8 ″ passing through the objective lens 802 are laser light having a small circle in the circular ring by a center slit 803 (FIG. 9A). ), Light of a small circle in a ring formed by the split light L8 'may be filtered. Therefore, the laser light passing through the center slit 803 may be modulated into a ring-shaped laser light (FIG. 9B).

The ring-shaped laser light (FIG. 9B) that has passed through the center slit 803 is part of the side of the ring-shaped laser light of the ring-shaped (FIG. 9B) by the side slits 804. Can be filtered. Therefore, the laser light passing through the side slit 804 can be modulated into an 8-shaped laser light (FIG. 9C).

Accordingly, the circular Gaussian laser light may be converted into an eight-character shape through the laser light modulator 800 including the birefringent lens 801, the objective lens 802, and the plurality of slits 803 and 804 of FIG. 8. It can modulate with 8-shaped laser light (FIG. 9C). The 8-shaped laser light modulated by the optical modulator 800 (FIG. 9C) is an 8-shaped modulated by the optical modulator 600 using the slit of FIG. 6. Compared with (8-shaped) laser light, the light at the center can be blocked and the intensity of the light at the center can be relatively weak. In addition, when compared to the spatial light modulator 700 of FIG. 7, external power may not be required. Hereinafter, a mode of a circular Gaussian laser light is changed to a cylindrical vector beam (CVB). An embodiment of modulating and finally modulating the modulated cylindrical vector beam (CVB) with an 8-shaped laser light will be described in more detail with reference to the drawings.

Cylindrical Vector Beam (CVB) is a vector beam solution of Maxwell's equation that satisfies symmetry about an axis in both amplitude and phase of light. CVB can have radial and azimuthal polarization.

FIG. 10A illustrates CVB having radial polarization, and FIG. 10B illustrates CVB having azimuthal polarization. The CVB has a ring shape as shown in FIG. 10. When referring to FIG. 10C, the light intensity decreases toward the center of the CVB, and the light intensity increases toward the side of the CVB. It becomes In FIG. 8, the shape and shape of the ring-shaped light (FIG. 9B) produced by the birefringence phenomenon may be substantially similar. However, CVB has a difference compared to the ring-shaped light of FIG. 9 (b) in which the direction of polarization is symmetric about an axis and the polarization direction is not symmetric about the central axis.

FIG. 11 is a diagram illustrating a laser light modulator 1100 modulating a Gaussian laser light into a CVB and then modulating it again into an 8-shaped laser light according to an exemplary embodiment of the present disclosure. Referring to FIG. 11, the laser light modulator 1100 may include a CVB modulation module 1110 and an eight-shaped light modulation module 1120.

The CVB modulation module 1110 shown in FIG. 11 is a circular Gaussian laser light L11 emitted from the laser light output unit 110, and has a high-dimensional cylindrical vector beam in which the amplitude and phase of the light are symmetrical to the central axis. Modulation is performed using Cylindrical Vector Beam (CVB) (L11 '). In this case, the modulated CVB (L11 ') may be a radial CVB (FIG. 10 (a)) or an azimuth CVB (FIG. 10B) in which the direction of polarization is symmetric about an axis. The method of modulating the Gaussian laser light L11 to CVB will be described in detail later.

The CVB modulation module 1100 may be classified into two types according to the location where the CVB modulation module 1100 is included.

First, the CVB modulation module 1100 may be combined with the laser light emitting unit 110 to exist together in one system. In this case, CVB (L11 ') may be dominantly oscillated, and modes other than the high-level CVB (L11') mode may be suppressed in the modulation system. In the CVB modulation module 1100, the CVB L11 ′ may be oscillated dominantly, thereby enabling structural miniaturization of the modulation system. However, the difficulty of implementing the CVB modulation module 1100 may be somewhat high. The CVB modulation module 1100 may include a conical Brewster Prism (CBP), a Sagna Interferometer, an optical fiber polarization controller, a special optical fiber, a fiber grating, and the like.

Secondly, the CVB modulation module 1100 may exist in another system from the outside spaced apart from the laser light output unit 110. The CVB modulation module 1100, which is spaced apart from the laser light emitting unit 110 and is present as another system from the outside, modulates the Gaussian light L11 emitted from the laser light emitting unit 110 to the CVB L11 ′. Can be. Since the modulation system may be spaced apart from the laser light output unit 110, the modulation system may be effectively applied to a conventional semiconductor cutting facility using the conventional Gaussian laser light L11. However, the complexity of the optical system of the CVB modulation module 1100 may increase, so that the management difficulty may be somewhat high. The CVB modulation module 1100 may include, for example, an acoustic waver, a microstructure grating, a spatial light modulator, and the like.

 An eight-shaped light modulation module 1120 shown in FIG. 11 has a shape of an eight-shaped light L11 ″ that will focus a CVB L11 ′ modulated by the CVB modulation module 1100 onto a semiconductor substrate. Can be modulated by When the modulated 8-shaped light L11 ″ is incident on the substrate, the incident 8-shaped laser light L 11 ″ does not spatially overlap with the previously formed modified regions and cracks so that the light is inside the substrate. The scattering of (L11 ”) can be prevented to prevent optical damage to the substrate.

12 to 15 illustrate various embodiments of modulating a circular Gaussian laser light emitted from the laser light output unit 110 into CVB. The method of modulating Gaussian laser light into CVB itself has been studied in various ways since 1972. CVB modulation embodiments to be described below are described in Q. Zhan, Advances In Optics and Photonics, Vol. 1, 2009 and R. Zheng, C. Gu, A. Wang, L. Xu, H. Ming, An all-fiber laser generating cylindrical vector beam, Opt. Express 18, 2010, which are hereby incorporated by reference in their entirety.

12 illustrates a CVB modulation module 1210 using spiral elements in accordance with an exemplary embodiment of the present disclosure. Referring to FIG. 12, the CVB modulation module 1210 using the spiral element may include a radial analyzer 121, a spiral phase element (SPE) 122, and half-wave plates 123. have.

The CVB modulation module 1210 generally modulates a Gaussian light L12 having spatially homogeneous polarization emitted from the laser light emitting unit 110 into a CVB having spatially heterogeneous polarization. The radial analyzer 121 is a device in which the polarization transmission axis is aligned along either radial or azimuth. The light L12 before being incident on the radial analyzer 121 may be a Gaussian laser light having generally homogeneously polarized light. For example, the Gaussian laser light L12 before being incident may have linear or circular homogeneous polarization. When the light L12 passes through the radial analyzer 121, the light L12 may be polarized radially or azimuthally according to the direction of the polarization transmission axis of the radial analyzer.

Spiral element (SPE) 122 of FIG. 12 may have opposite helicity to compensate for the geometrical phase, in order to make the light L12 into CVB (L12 '). The helical element 122 may be generated in a variety of ways, such as by electro-optical lithography or spatial light modulators.

The half-wave plates 123 connected in series in FIG. 12 may function to rotate the polarization of the light passing through the spiral element SPE in a desired pattern.

Thus, referring to FIG. 12, a Gaussian laser light L12 having a spatially homogeneous polarization is generated by the radial analyzer 121, the spiral phase element (SPE) 122, and the CVB modulation module 1210. It can be modulated into a radially or azimuthally polarized CVB (L12 ') via half-wave plates 123.

13 illustrates CVB modulation using multiple spatial light modulators in accordance with an exemplary embodiment of the present disclosure. Referring to FIG. 13, the CVB modulation module 1310 using the plurality of spatial light modulators includes a pair of spatial light modulators 131a and 131b, a quarter wave plate 132, and a plurality of optical lenses. 133). The laser light L13 having a Gaussian distribution incident on the CVB modulation module 1310 using the spatial light modulator is incident on the first spatial light modulator 131a by the plurality of optical lenses 133, and the first space. The light modulator 131a modulates the incident light L13 into the phase pattern of CVB. The light of which the phase pattern is modulated may be incident to the second spatial light modulator 131b through the quarter wavelength plate 132 through the plurality of optical lenses 133. The incident light may be modulated into a ring-shaped CVB (L13 ') having polarized light symmetric about a central axis through the quarter wavelength plate 132 and the second spatial light modulator 131b.

Accordingly, the Gaussian distribution laser light L13 may be modulated into a radial or azimuth CVB L13 'after passing through the CVB modulation module 1310 of FIG.

14 is a diagram of a CVB modulation module 1410 using an optical fiber polarization controller according to an exemplary embodiment of the present disclosure. Referring to FIG. 14, the optical fiber polarization controller 1410 includes a loop mirror 141, a wavelength division multiplexer 142, an ytterbium fiber 143, a fiber collimator 144, and a polarization controller 145. It may include. The process of generating CVB through the optical fiber polarization controller 1410 is R. Zheng, C. Gu, A. Wang, L. Xu, H. Ming, An all-fiber laser generating cylindrical vector beam, Opt. Express 18, 2010, which is incorporated in more detail and is incorporated herein in its entirety. The laser light generated by the optical fiber polarization controller 1410 may be a CVB with radial or azimuthal polarization, the CVB may be dominantly oscillated within the CVB modulation module 1410, and may be other than a high-level CVB mode. Modes may be suppressed in the CVB modulation module 1410.

15 illustrates a CVB modulation module using a spatially divided half-wave plate according to an exemplary embodiment of the present disclosure. Referring to FIG. 15, the CVB modulation module may be composed of a half wavelength plate 1500 that is spatially divided into various parts. When circular Gaussian light L15 having spatially homogeneous polarization emitted from the laser light output unit 110 is input to the spatially divided half-wave plate 1500, the spatially different axial direction has a different axial direction. Through the half-wave plate, the spatially homogeneous Gaussian light L15 may be modulated into CVB L15 'having polarized light symmetric about an axis. This can be achieved by gluing several segmented half-wave plates with different crystal angles into one plate. Therefore, by using the spatially divided half-wave plate 1500, it is possible to modulate the Gaussian light (L15) to CVB (L15 ').

The Gaussian laser light emitted from the laser light emitting unit may be modulated into the CVB through the CVB modulation modules of the various embodiments of FIGS. 12 to 15. The CVB is not limited to the embodiment of the present disclosure and may be generated in more various ways.

For example, an embodiment of a CVB modulation module coupled with a laser light exit to dominantly oscillate CVB in a system, such as Conical Brewster Prism (CBP), Sagnal Interferometer, Fiber Optic Polarization Controller , Special optical fibers, fiber gratings, and the like. In addition, examples of a CVB modulation module that is spaced apart from the laser light emitting unit and oscillates CVBs include acoustic wavers, microstructures gratings, and spatial light modulations. Can be.

The CVB modulation module of the present disclosure may include all of the CVB modulation modules exemplarily disclosed above, and may include a CVB modulation module configured with more various devices without being limited to the above-described embodiment of the present invention. The CVB modulated through the CVB modulation module may have radial polarization (FIG. 10A) or azimuth polarization (FIG. 10B).

16 is a diagram illustrating a polarization filter as an example of an eight-shaped light modulation module according to an exemplary embodiment of the present disclosure. Referring to FIG. 16, the CVB L16 having the radial polarization modulated by the CVB modulation module 1110 or the CVB L16 ′ having the azimuth polarization may be incident to the eight-shaped light modulation module 1600. The modulated CVB may pass through the eight-shaped light modulation module 1600 to be modulated into eight-shaped light. The eight-shaped light modulation module 1600 may be configured as a polarization filter, and may include a vertical polarization filter 1601 or a horizontal polarization filter 1602 in one embodiment.

A polarizing filter is a kind of filter used to produce linear polarization of light. After applying a needle-like iodide quinine sulfate crystal to a thin film made of cellulose nitrate, the crystal is evenly aligned by applying an electric or magnetic field to the film. Can be made. The light in which the polarization direction is parallel to the acicular crystal is absorbed well, and the light in the vertical direction passes through as it is. Therefore, the polarization direction of the light passing through the polarization filter is orthogonal to the needle crystal direction, and the light passing through may be linearly polarized light.

 17A and 17B are diagrams illustrating shapes in which radial and azimuth CVBs are modulated into 8-shaped light by vertical and horizontal polarizing filters according to exemplary embodiments of the present disclosure, respectively.

Referring to FIG. 17A, the CVB L17a having radial polarization may be modulated into an eight-shaped light L17a 'through the vertical polarization filter 1701. The vertical polarization filter 1701 passes only the CVB having the polarization of the vector component in the vertical direction, and does not pass the CVB having the polarization of the vector component in the horizontal direction. Therefore, when the horizontal axis and the vertical axis are drawn based on the ring-shaped center in the radial CVB, since the polarization direction of the CVB is orthogonal to the polarization filter on the horizontal axis, light may be blocked by the polarization filter and absent. In the vertical axis, since the polarization direction of CVB is parallel to the polarization filter, light can be passed without being blocked by the polarization filter. When the CVB having the polarization vector in the diagonal direction is decomposed along the horizontal and vertical axes of the CVB, the polarization vector of the horizontal axis component is blocked by the vertical polarization filter 1701, and the polarization vector of the vertical axis component is vertical polarization. It can pass through the filter without being blocked by the filter 1701. Therefore, the CVB L17a having radial polarization may be modulated into 8-shaped light by the vertical polarization filter 1701. The 8-shaped light L17a 'modulated by the radial CVB L17a may have a polarization vector having a vertical axis component parallel to the direction of the vertical polarization filter as shown in FIG. 17A. Referring to FIG. 17A, the arrows represented inside the eight-shaped light L17a 'describe the intensity and polarization direction of the modulated eight-shaped light L17a'. The arrow represented inside the 8-shaped light L17a 'of FIG. 17A is parallel to the direction of the vertical polarization filter 1701 and is closer to the vertical axis (ie, 90 degrees, near 270 degrees). The polarization vector of the modulated eight-shaped light L17a 'is parallel to the direction of the vertical polarization filter 1701, and the intensity of the light is relatively high near the longitudinal axis (i.e., around 90 degrees and 270 degrees). Means that.

Likewise, referring to FIG. 17B, the CVB L17b having the azimuth polarization may be modulated into an eight-shaped light L17b ′ through the horizontal polarization filter 1702. The horizontal polarization filter 1702 passes only the CVB having the polarization of the vector component in the horizontal direction, and does not pass the CVB having the polarization of the vector component in the vertical direction. Therefore, when the horizontal axis and the vertical axis are drawn based on the ring-shaped center in the azimuth-type CVB, since the polarization direction of the CVB is orthogonal to the polarization filter on the horizontal axis, light may be blocked by the polarization filter and absent. In the vertical axis, since the polarization direction of CVB is parallel to the polarization filter, light can be passed without being blocked by the polarization filter. When a CVB having a polarization vector in the diagonal direction is decomposed along the horizontal and vertical axes of the CVB, the polarization vector of the vertical component is blocked by the horizontal polarization filter 1702, and the polarization vector of the horizontal component is horizontal polarization. It may pass through the filter without being blocked by the filter 1702. Therefore, the CVB L17b having the azimuth polarization by the horizontal polarization filter 1702 can be modulated into 8-shaped light. The 8-shaped light L17b 'modulated by the azimuth CVB L17b may have a polarization vector having a horizontal axis component parallel to the direction of the horizontal polarization filter as shown in FIG. 17B. Referring to FIG. 17B, the arrows represented inside the eight-shaped light L17b 'describe the intensity and polarization direction of the modulated eight-shaped light L17b'. The arrow represented inside the 8-shaped light L17b 'of FIG. 17B is parallel to the direction of the horizontal polarization filter 1702 and is closer to the vertical axis (ie, 90 degrees, near 270 degrees). Long, which means that the polarization vector of the modulated eight-shaped light L17b 'is parallel to the direction of the horizontal polarization filter 1702, and the intensity of the light is relatively high near the longitudinal axis (i.e., around 90 degrees and 270 degrees). Means that.

18 is a graph showing intensity according to angles of CVB and 8-shaped light according to an exemplary embodiment of the present disclosure. Referring to FIG. 18, it can be seen that the radial CVB L18 modulated by the CVB modulation module is modulated by the vertical polarization filter 1800 into 8-shaped light L18 '. The radial CVB L18 modulated by the CVB modulation module may have a constant intensity of light according to the rotational direction (0 to 360 degrees) of the azimuth angle Θ. The radial CVB L18 having the constant light intensity may be modulated into the eight-shaped light L18 'by the vertical polarization filter 1800, and the intensity of the modulated eight-shaped light L18' is the direction of rotation of the azimuth angle. The absolute value sine curve can be made according to (0 to 360 degrees). When the azimuth angle is 0 degrees and 180 degrees, the intensity of the modulated eight-shaped light L18 'is ideally zero, and when the azimuth angle is 90 degrees and 270 degrees, the intensity of the modulated eight-shaped light L18' is ideally radial CVB. May be equal to and have a maximum value (M).

In the graph shown in FIG. 18, portions having an intensity of light equal to or greater than 1 / SQRT (2) or more than the maximum value M of the maximum intensity M of the modulated eight-shaped light L18 'are indicated by hatching. More specifically, the hatched portion may be 45 degrees to 135 degrees and 225 to 315 degrees of the azimuth angle. The intensity of the modulated eight-shaped light L18 'having a maximum value M greater than or equal to 1 / SQRT (2) of the maximum value M of the modulated eight-shaped light L18' is determined by the substrate cutting. It can be the main light intensity in laser processing. If the portion having the light intensity of 1 / SQRT (2) or more and the maximum value (M) of the maximum value (M) is shown, the shape of the 8-shaped laser light L18 'as shown in FIG. It can be expressed as.

The description of the embodiment of the present disclosure of FIG. 18 may be similarly applied when the azimuth CVB modulated by the CVB modulation module is modulated into 8-shaped light by the horizontal polarization filter and the principle is substantially the same as above.

In the foregoing descriptions of FIGS. 6 to 18 and the embodiment of the present disclosure, it has been described that the Gaussian laser light is finally modulated into 8-shaped light through the light modulator. In more detail, various embodiments of modulating Gaussian laser light into 8-shaped laser light without modulating Gaussian laser light through CVB are described with reference to FIGS. 6 to 9, and various embodiments of modulating Gaussian laser light into CVB through FIGS. 10 to 15. An example is described, and an embodiment in which CVB modulated in Gaussian laser light is modulated into 8-shaped laser light is described with reference to FIGS. 16 to 18.

 Hereinafter, a cutting laser device including the light modulator and a method of cutting a substrate using the cutting laser device will be described in detail with reference to FIGS. 19 to 23.

19 is a configuration diagram showing an outline of cutting processing of a cutting laser device according to an exemplary embodiment of the present disclosure. Referring to FIG. 19, the cutting laser device 1900 may include a laser cutting part 1901, a distance measuring part 1902, and a substrate mounting part 1904. The laser cutting processing unit 1901 and the distance measuring unit 1902 of the cutting laser device 1900 may be connected to a control unit 1903 that controls the driving of the cutting laser device.

The laser cutting processing unit 1901 of the cutting laser device 1900 includes a light output unit 191, a light modulation unit 192, a transmission optical unit 193, a condenser lens unit 194, and a condenser driving unit 195. , And the position driving unit 196.

The light output unit 191 emits laser light for processing for forming a modified region and a crack in the substrate S. As shown in FIG. For example, the laser light L19 emitted from the light output unit 191 may be Gaussian light having a Gaussian distribution of light intensity, have a pulse width of 1 dB or less, and a peak power density at the converging point. May be about 1 × 108 (W / cm 2).

The light modulator 192, the transfer optical unit 193, and the condenser lens unit 194 may be sequentially disposed on the optical path of the processing laser light L19 emitted from the light output unit 191.

6A to 18, the light modulating unit 192 has a relatively high intensity of light in the vicinity of a processing Gaussian laser light L19 emitted from the light output unit 191 in a direction parallel to the laser processing direction. Modulate with reduced laser light. In one embodiment, the light modulator 192 may modulate the emitted Gaussian laser light L19 into an 8-shaped laser light.

The method for modulating the Gaussian laser light L19 of the light modulator 192 into an 8-shaped laser light may be, for example, by the method according to various embodiments of the present disclosure of FIGS. Can be.

The eight-shaped laser light L19 ′ modulated by the light modulator 192 may reach the condenser lens unit 194 through the transmission optical unit 193. The transmission optical unit 193 may be a dichroic mirror. The dichroic mirror is a reflector composed of many thin layers of materials having different refractive indices. The dichroic mirror reflects light of a predetermined wavelength and transmits light of a predetermined wavelength. The transmission optical unit 193 may transmit the laser light L19 'to the condensing lens unit 194 by transmitting the modulated eight-shaped laser light L19'. In addition, the transmission optical unit 193 may reflect the laser light for distance measurement emitted from the distance measuring unit 1902, which will be described later.

The condenser lens unit 194 condenses the modulated eight-shaped laser light L19 'such that the modulated eight-shaped laser light L19' is condensed inside the substrate S to form a modified region and a crack. . The condenser driver 195 may be coupled to the condenser lens unit 194 in order to control the position of the condensing point of the modulated eight-shaped laser light L19 ′ condensed by the condenser lens unit 194. The condensing driver 195 is driven by a command signal from the controller 1903 which has received the distance between the substrate S measured by the distance measuring unit 1902 and the condensing lens unit 194, which will be described later. The location of 194 may be controlled. Therefore, in the substrates S of various thicknesses, the laser light may be collected in the vicinity of the height which is most effective for cutting the substrate to form modified regions and cracks.

In addition, when the laser cutting part 1901 forms a reformed region and a crack in one region of the substrate S, the position driving unit 196 may control the laser cutting part 1901 by a control command of the controller 1903. Can be moved in the direction of the cutting line.

In addition, although not shown in FIG. 19, the position driving unit may be coupled to the substrate seating unit 1903 instead of the laser cutting processing unit 1901. The position driver may move the substrate S along the substrate seating portion 1904 in the cutting line direction by a control command of the controller 1903.

Therefore, the position driving unit may be coupled to the laser cutting processing unit 1901 or the substrate mounting unit 1904 to adjust the relative positions of the substrate S and the laser cutting processing unit 1901.

The eight-shaped laser light focused on the semiconductor substrate seated on the substrate seating portion 1904 through the cutting processing portion 1901 is absent in the eight-shaped shape or the intensity of light is relatively high. As a result, the weak 8-sided side portion may contact the cutting processing line formed on the semiconductor substrate, and the upper and lower surface portions of the 8-character strong light intensity may fall on the cutting processing line on the semiconductor substrate. Therefore, the 8-shaped laser light incident in the substrate S and relatively moved in the cutting direction does not overlap the modified regions and cracks formed by the 8-shaped laser light in advance. It is not scattered within. Accordingly, it is possible to prevent optical damage of the semiconductor elements formed on the semiconductor substrate.

20 is a configuration diagram illustrating an outline of distance measurement of a cutting laser device according to an exemplary embodiment of the present disclosure. The distance measuring unit 2000 may include a distance measuring light output unit 21, a condenser lens 22, a pinhole 23, a knife edge 24, an illumination system lens 25, a half mirror 26, and a focus lens ( 27, an imaging lens 28, a detector 29, and a signal processor 30.

Referring to FIG. 20, the distance measuring laser light L20 emitted from the distance measuring light output part 21 passes through the condensing lens 32 and the pinhole 23, by the knife edge 24. Some may be blocked. The laser light L20 for distance measurement not blocked by the knife edge 24 is reflected by the half mirror 26 after passing through the illumination system lens 25, and is transmitted to the transmission optical unit through the focus lens 27. 193). The transmission optical unit 193 may be a dichroic mirror, and the dichroic mirror is a reflector made of many thin layers of materials having different refractive indices and may reflect light of a certain wavelength and transmit light of a certain wavelength. Can be. The dichroic mirror may reflect the laser light L20 for distance measurement. The reflected distance measuring laser light L20 travels along a shared optical path of the processing laser light, is collected by the condenser lens 194, and is irradiated onto the substrate S. The reflected light of the distance-measuring laser light L20 irradiated onto the substrate S returns to the condenser lens 194 and travels along a shared optical path, and is reflected by the transmission optical unit 193 to focus the lens 27. The half mirror 26 may be sequentially passed and collected by the imaging lens 28, and may be irradiated onto the detector 29. The detector 29 transmits an output signal according to the amount of light of the detected distance measuring laser light L20 to the signal processor 30. The control unit 2100 receiving the output signal may adjust the focusing point of the laser light L20 for distance measurement by adjusting the position of the focus lens 27 through the driving unit 210.

In addition, by transmitting a signal to the control unit 2100 driver 211 receiving the signal transmitted from the distance measuring unit 2000 to adjust the position of the condenser lens 194, the laser light for processing is collected at a predetermined depth in the substrate It can be done.

Through the laser cutting part 2200, the distance measuring part 2000, and the control part 2100 of FIG. 20, the modified region and the crack may be continuously formed on the cutting line of the semiconductor substrate S. FIG.

As shown in FIG. 21, when the formation of the reformed region and the crack is continuously completed in the substrate S along the cutting line, an external force is applied to the semiconductor substrate S to expand the crack to cut the individual semiconductor substrate.

22 and 23 are flowcharts illustrating a flow of a method of cutting a semiconductor substrate, according to an exemplary embodiment of the present disclosure. Referring to FIG. 22, in a method of cutting a semiconductor using a cutting laser device, an embodiment of the present disclosure includes a light emitting step 2210 in which laser light is emitted. In the light output step 2210, a laser beam for processing for forming a modified region and a crack is emitted to the inside of the substrate S. For example, the laser light emitted in the light exiting step 2210 may be Gaussian light having a Gaussian distribution of light intensity, a pulse width of 1 ㎲ or less, and a peak power density at the converging point is 1 ×. It may be about 108 (W / ㎠).

The laser light for processing emitted in the light output step 2210 may go through a light modulation step 2220, a light transmission step 2230, and a light condensing step 2240 in order.

The light modulation step 2220 is the intensity in the vicinity of the direction parallel to the laser processing direction of the processing Gaussian laser light (L22) emitted in the light output step 2210, as in the salping embodiments in FIGS. The relative shape of the Gaussian laser light L22 may be modulated by relatively decreasing. In an embodiment, the light modulation step 2220 may modulate the Gaussian laser light L22 into an 8-shaped laser light L22 ″.

The light modulation step 2220 may be performed using an 8-shaped light without modulating the Gaussian laser light L22 into the high-dimensional CVB as in the embodiments of the present invention disclosed in FIGS. 5 to 8. L22 ”).

In addition, the light modulation step 2220 modulates the Gaussian laser light L22 to a high-dimensional CVB (L22 ') as in the embodiments of the present invention disclosed in FIGS. L22 ') may be modulated into 8-shaped light L22'.

The modulated eight-shaped laser light L22 'may be transmitted through a light transmission step 2230, and the light transmission step 2230 may include at least one lens and / or a mirror. In one embodiment, the light transmission step 2230 may use a dichroic mirror. The light transmitting step 2230 transmits the laser light L22 'to the light condensing step 2240 by transmitting the modulated eight-shaped laser light L22 ″.

The transmitted modulated eight-shaped laser light L22 ′ may be collected inside the semiconductor substrate S through the light condensing step 2240. The light condensing step 224 may include a light collecting lens. More specifically, in the light condensing step 2240, the processing eight-shaped laser light L22 ″ may be condensed inside the substrate S by using a condenser lens to form a modified region and a crack in the substrate S. FIG. A driving step (not shown) may be added to control the location of the focusing point of the modulated eight-shaped laser light L22 ″ condensed by the light condensing step 2240. The driving step (not shown) may control the position of the condenser lens of the light condensing step 2240 by driving by the command signal of the control unit 1903 receiving the signal by the distance measuring step to be described later.

When formation of the reformed region and the crack is completed in one region inside the substrate S, the driving step (not shown) may be performed by the control command of the controller in the direction of the cutting line or the cutting portion of the cutting laser device. Can be moved relatively. Therefore, continuous modification regions and cracks may be formed in the semiconductor substrate S. FIG. In this case, the laser light focused in the semiconductor substrate S may not be spatially overlapped with the modified regions and cracks previously formed in the shape of an 8 shape, so that the laser light may not be scattered in the substrate, thereby preventing optical damage of the substrate.

The light emitting step 2210, the light modulating step 2220, the light transmitting step 2230, the light collecting step 2240, and the moving step 2250 of the cutting laser device are continuously performed on the semiconductor substrate S. The modified regions and cracks generated are subjected to an external force on the semiconductor substrate to expand the cracks and cut them into semiconductor chips (2260), thereby completing the cutting of the semiconductor substrate.

Referring to FIG. 23, the laser light transmitting step 2230 may further include a distance measuring step 2301. The distance measuring step 2301 is a step 2310 of measuring a distance between the condenser lens and the substrate S, and after the signal of the measured distance is transmitted to the controller, the controller transmitting a command signal to the driver 2320. In operation 2330, the driving unit receiving the command signal drives the lens. The principle and operation method of the distance measuring step 2301 are the same as the embodiment disclosed in FIG. 20.

As described above, exemplary embodiments have been disclosed in the drawings and the specification. Although embodiments have been described using specific terms in this specification, they are used only for the purpose of describing the technical spirit of the present disclosure and are not used to limit the scope of the present disclosure as defined in the meaning or claims. . Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present disclosure will be defined by the technical spirit of the appended claims.

Claims (20)

An emission step of emitting a Gaussian laser light; And
And a modulating step of modulating the shape of the Gaussian laser light by reducing the intensity in the vicinity of the direction parallel to the laser processing direction of the Gaussian laser light emitted in the emitting step. The method of claim 1,
And wherein said modulating step comprises modulating said Gaussian laser light into an 8-shaped laser light. The method of claim 2,
The modulating step includes modulating the Gaussian laser light into an 8-shaped laser light using at least one of a spatial light modulator (SLM) and a slit. Laser light modulation method. The method of claim 2,
The modulation step,
A division step of dividing a Gaussian laser light emitted in the exiting step through birefringence;
A center filtering step of filtering the centers of the light split in the dividing step; And
A side filtering step of filtering the side of the light filtered in the center filtering step;
Laser light modulation method comprising a. The method of claim 2,
The modulation step,
A CVB modulation step of modulating a Gaussian laser light emitted in the emitting step into a cylindrical vector beam (CVB); And
An eight-dimensional light modulation step of modulating the CVB modulated in the CVB modulation step into an eight-shaped laser light;
Laser light modulation method comprising a. The method of claim 5,
And said CVB modulation step comprises at least one of a spiral element, a plurality of spatial light modulators, an optical fiber polarization controller, and a spatially divided half-wave plate. The method of claim 6,
The eight-character light modulation step is characterized in that using a polarizing filter. Gaussian laser light emitting unit;
An optical modulator for modulating the shape of the Gaussian laser light by reducing an intensity in the vicinity of a direction parallel to the laser processing direction of the emitted Gaussian laser light;
A transmission optical unit for optically moving the modulated laser light;
A condenser lens unit configured to condense the modulated laser light; And
A semiconductor substrate mounting portion on which the semiconductor substrate to be cut is mounted;
Including,
And the modulated laser light is focused to the inside of the semiconductor substrate seated on the semiconductor substrate mounting portion. The method of claim 8,
The light modulator
And a laser device for modulating the emitted Gaussian laser light into an 8-shaped laser light. The method of claim 9,
And the optical modulator comprises at least one of a spatial light modulator (SLM) and a slit. The method of claim 9,
The optical modulator may include a birefringent lens that splits the Gaussian laser light;
A center slit for filtering a center of laser light split from the birefringent lens; And
A side slit for filtering the side of the laser light whose center is filtered by the center slit;
Laser device for cutting, comprising a. The method of claim 9,
The optical modulator may include: a CVB modulation module configured to modulate the Gaussian laser light into a CVB (Cylindrical Vector Beam); And
An eight-character optical modulation module configured to modulate the CVB modulated by the CVB modulation module with eight-shaped laser light;
Laser device for cutting, comprising a. The method of claim 12,
And said CVB modulation module comprises at least one of a spiral element, a plurality of spatial light modulators, an optical fiber polarization controller, and a spatially divided half-wave plate. The method of claim 13,
The eight-way optical modulation module for cutting laser device characterized in that it comprises a polarizing filter. In the substrate cutting method using a laser device for cutting,
A light emission step of emitting a Gaussian laser light;
A light modulation step of modulating the shape of the Gaussian laser light by reducing the intensity in the vicinity of the direction parallel to the laser processing direction of the emitted Gaussian laser light;
A light transfer step of optically shifting the modulated laser light;
A light condensing step of condensing the modulated laser light;
A crack forming step of focusing the focused laser light into a substrate to form a modified region and a crack;
An apparatus driving step for relatively moving the laser apparatus and the substrate in a cutting direction; And
And cutting the substrate by cutting the substrate by applying an external force to the substrate to expand the formed cracks. The method of claim 15,
And the optical modulation step modulates the emitted Gaussian laser light into an 8-shaped laser light. The method of claim 16,
And said optical modulation step comprises at least one of a spatial light modulator and a slit. The method of claim 16,
The light modulation step may include: a light splitting step of splitting the emitted Gaussian laser light through a birefringent lens;
A center filtering step of filtering the centers of the laser light split in the light splitting step; And
A side filtering step of filtering side surfaces of the laser light filtered in the center filtering step;
Substrate cutting method comprising a. The method of claim 16,
The optical modulation step may include: a CVB modulation step of modulating a Gaussian laser light emitted in the light output step into a CVB (Cylindrical Vector Beam);
An eight-shaped light modulation step of modulating the modulated CVB into eight-shaped light;
Substrate cutting method comprising a. The method of claim 19,
The CVB modulation step includes at least one of a spiral element, a plurality of spatial light modulators, an optical fiber polarization controller, and a spatially divided half-wave plate,
And said eight-shaped light modulation step comprises a polarizing filter.

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