Substrate cutting method and method of manufacturing semiconductor device

Abstract

A substrate cutting method and a method of manufacturing a semiconductor device are provided. The substrate cutting method can include forming a modification pattern in a substrate using a laser beam, grinding a bottom surface of the substrate to thin the substrate, and stretching the substrate to divide the substrate into a plurality of semiconductor chips. The forming of the modification pattern can include forming a first modification pattern in the substrate and providing an edge-focused light beam to an area intersecting the first modification pattern to form a second modification pattern in contact with the first modification pattern.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a method of manufacturing a semiconductor device, and in particular, to a substrate dicing method, a method of manufacturing a semiconductor device using the substrate dicing method, and / or a semiconductor chip manufactured by the methods. BACKGROUND

[0002] Generally, a semiconductor manufacturing process includes front-end-of-line processes and back-end-of-line processes, which are respectively referred to as wafer-level processes and assembly processes. Between the front-end-of-line processes and the back-end-of-line processes, a substrate dicing process is performed to separate a substrate into semiconductor chips or dies. For example, the substrate is cut along a scribe lane by using a dicing machine or a laser beam. In this case, the substrate is divided into semiconductor chips or dies that are separated from each other. SUMMARY

[0003] Embodiments of the inventive concept provide a substrate dicing method and / or a method of manufacturing a semiconductor device using the substrate dicing method, which can limit and / or prevent a dicing crack from being damaged.

[0004] According to an embodiment of the inventive concept, a substrate dicing method can include forming a modification pattern in a substrate using a laser beam, grinding a bottom surface of the substrate to thin the substrate, and stretching the substrate to divide the substrate into a plurality of dies. Forming the modification pattern can include forming a first modification pattern in the substrate, and providing an edge-focused light beam to an area intersecting the first modification pattern to form a second modification pattern in contact with the first modification pattern.

[0005] According to an embodiment of the inventive concept, a substrate dicing method can include forming a modification pattern in a substrate using a laser device, and stretching the substrate to divide the substrate into semiconductor chips. The laser device can include a light source, an objective lens, a first axicon lens, and a second axicon lens. The light source can be configured to generate a laser beam. The objective lens can be between the light source and the substrate. The first axicon lens and the second axicon lens can be between the objective lens and the light source. The first axicon lens and the second axicon lens can be configured to generate an edge-focused light beam from the laser beam. The first axicon lens and the second axicon lens can respectively include a first tilted surface and a second tilted surface tilted at a tilt angle of 51.3° with respect to an optical axis of the laser beam.

[0006] According to an embodiment of the inventive concepts, a method of manufacturing a semiconductor device can include forming a thin film on a substrate, and dicing the substrate to separate the substrate into a plurality of semiconductor chips. Dicing the substrate can include forming a modification pattern in the substrate using a laser beam, grinding a bottom surface of the substrate to thin the substrate, and stretching the substrate to separate the substrate into the plurality of semiconductor chips. Forming the modification pattern can include forming a first modification pattern in the substrate, and providing an edge focused beam to an area intersecting the first modification pattern to form a second modification pattern in contact with the first modification pattern.

[0007] According to an embodiment of the inventive concepts, a semiconductor chip can include a substrate and a thin film on the substrate. The substrate can have a first side surface, a second side surface, and a corner between the first side surface and the second side surface. The substrate can include a first modification pattern on the first side surface and a second modification pattern on the second side surface. The first modification pattern and the second modification pattern can be in contact with each other at the corner. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a flowchart illustrating a method of manufacturing a semiconductor device according to an embodiment of the inventive concepts.

[0009] Figure 2 is a plan view illustrating an example of a thin film formed on a substrate.

[0010] Figure 3 is a flowchart illustrating example operations of dicing Figure 2 a substrate to separate the substrate into semiconductor chips spaced apart from each other.

[0011] Figure 4 and Figure 5 are enlarged plan views each illustrating Figure 2 part A of

[0012] Figure 6 is a cross-sectional view corresponding to line I-I' of Figure 4

[0013] Figures 7 to 9 is a cross-sectional view corresponding to line II-II' of Figure 5

[0014] Figure 10 is a flowchart illustrating example operations of forming a modification pattern in a substrate of Figure 2

[0015] Figure 11 is a diagram illustrating an example of a center focused beam of Figure 6

[0016] Figure 12 is a diagram illustrating an example of an edge focused beam of Figure 7 ​​​​An example illustration of an edge-focused beam.

[0017] Figure 13 It displays the energy of the edge-focused beam provided to the second focal point relative to... Figure 7 The curves of the first and second tilt angles.

[0018] Figure 14 It is displayed to Figure 7 The graph shows the first power of the center-focused beam and the second power of the edge-focused beam at the second focal point.

[0019] Figure 15 It is shown by Figure 6 A planar diagram of a typical modified pattern formed by a centrally focused beam.

[0020] Figure 16 It is shown Figure 9 A perspective view of an example semiconductor chip.

[0021] Figure 17 It shows the cutting Figure 2 A flowchart of another example operation of the substrate. Detailed Implementation

[0022] Figure 1 A method for manufacturing a semiconductor device according to one embodiment of the inventive concept is shown. Figure 2 A thin film 10 formed on a substrate W is shown.

[0023] Reference Figure 1 and Figure 2 The manufacturing process system can be configured to form a thin film 10 on a substrate W (in S100). The manufacturing process system may include a thin film deposition apparatus, a photolithography apparatus, an etching apparatus, and a cleaning apparatus, but the inventive concept is not limited to these examples. The substrate W may include a single-crystal silicon wafer. The thin film 10 may be formed on the top surface of the substrate W. In one embodiment, the thin film 10 may include an active region 12 and an active region 14.

[0024] Most of the active region 12 may be disposed near the central region of the substrate W. For example, each active region 12 may have a rectangular shape. Each active region 12 may be a device region or a chip region. Semiconductor devices may be formed in the active regions 12. Semiconductor devices may include volatile memory devices (e.g., DRAM devices), non-volatile memory devices (e.g., 3D NAND flash memory devices), or logic devices, but the inventive concept is not limited to this example. Each active region 12 may be defined by a dicing groove 20. For example, the dicing groove 20 may be provided to surround each active region 12.

[0025] The non-active region 14 can be disposed in the edge region of the substrate W. The non-active region 14 can be disposed outside the active region 12 to surround the active region 12. For example, each non-active region 14 can have a fan shape or a sector shape. Each non-active region 14 can be a non-device region.

[0026] Reference Figure 1 The substrate W can be cut into pieces using a cutting device. Figure 9 The semiconductor chip C (in S200). The cutting device may include a sawing device, Figure 6 First laser device 100 Figure 7 The second laser device 200 Figure 8 The polishing apparatus 300 and the stretcher are included, but the inventive concept is not limited to this example. The substrate W can be cut or diced along the dicing groove 20. For example, the substrate W can be cut or diced by a laser beam exposure and polishing (GAL) process. The substrate W can have a thickness of about 0.775 mm, but is not limited thereto. The thickness of the substrate W can be increased proportionally to the thickness of the pattern formed on the substrate W.

[0027] Figure 3 The cut was shown Figure 2 An example of operation S200 of dividing a substrate W into semiconductor chips C spaced apart from each other. Figure 4 and Figure 5 It is an enlarged plan view, in which each shows Figure 2 Part A. Figure 6 Is with Figure 4 The cross-sectional view corresponding to line I-I'. Figures 7 to 9 Is with Figure 5 The cross-sectional view corresponding to line II-II'.

[0028] Reference Figures 3 to 9The first laser device 100 and the second laser device 200 can form the modification pattern 30 in the scribe groove 20 of the substrate W using the first laser beam 102 and the second laser beam 202 (S210). The modification pattern 30 can be regularly formed (e.g., at a constant distance) in the scribe groove 20 of the substrate W. For example, the modification pattern 30 can be formed to be uniformly spaced apart from each other by a first center-to-center distance D1 in the first direction X and uniformly spaced apart from each other by a second center-to-center distance D2 in the second direction Y. The first center-to-center distance D1 can be equal to the second center-to-center distance D2. For example, each of the first center-to-center distance D1 and the second center-to-center distance D2 can be in a range of about 6 μm to about 10 μm. When viewed in a plan view, the modification pattern 30 can be spaced apart from each other by a distance of about 2 μm or less, or can be in contact with each other. Each modification pattern 30 can have an ellipsoidal shape elongated in a third direction Z. Each modification pattern 30 can have a width WD (e.g., see Figure 16 ) of about 1.5 μm to about 5 μm and a thickness T (e.g., see Figure 16 ) of about 20 μm.

[0029] The modification pattern 30 can have a material property different from that of the substrate W. For example, when the substrate W is formed of single crystalline silicon, each modification pattern 30 can include amorphous silicon or polycrystalline silicon. In an embodiment, the modification pattern 30 can include a first modification pattern 32 and a second modification pattern 34. For example, the first modification pattern 32 can be formed to be arranged in the first direction X. The second modification pattern 34 can be formed to be arranged in the second direction Y.

[0030] Figure 10 An example of the operation S210 of forming the modification pattern 30 in the substrate W of Figure 2 is illustrated.

[0031] Referring to Figure 4 , Figure 6 and Figure 10 , the first laser device 100 can provide the center focused beam 106 to an upper portion of the substrate W proximate to the thin film 10 in the first direction X, as a result, the first modification pattern 32 can be formed in the substrate W (in S212). The first laser device 100 can generate the center focused beam 106 using the first laser beam 102. In an embodiment, the first laser device 100 can include a first light source 110 and a first objective lens 120.

[0032] The first light source 110 can generate the first laser beam 102 and can provide the first laser beam 102 to the first objective lens 120. For example, the first light source 110 can include a laser diode. The first laser beam 102 can have a power and / or energy in a range of about 0.5 W to about 2.5 W. The first laser beam 102 can be provided in the form of first pulses 104. For example, the first pulses 104 can have a pulse frequency of about 100 kHz. The first laser beam 102 can pass through the substrate W. In an embodiment, the first laser beam 102 can have a first wavelength of, for example, about 1100 nm.

[0033] The first objective lens 120 can be disposed between the first light source 110 and the substrate W. The first objective lens 120 can include, for example, a convex lens. The first objective lens 120 can have a numerical aperture (NA) of about 0.8. The first objective lens 120 can convert the first laser beam 102 into a central focused beam 106. The first laser beam 102 can be a collimated beam, and the central focused beam 106 can be focused on a first focal point 122. The central focused beam 106 can pass through the bottom surface of the substrate W and can be focused on the first focal point 122. The central focused beam 106 can be used to form the first modified pattern 32 in the vicinity of the first focal point 122 located in the substrate W. The first modified pattern 32 can be formed in a portion of the substrate W located between the first objective lens 120 and the first focal point 122. For example, the first modified pattern 32 can be formed to have a first height h1 spaced apart from the thin film 10 by about 5 μm to about 10 μm. The first focal point 122 can be disposed between the first modified pattern 32 and the thin film 10. The first focal point 122 can be adjusted to be located at a second height h2 of about 2 μm to about 3 μm from the thin film 10.

[0034] Figure 11 An example of the central focused beam 106 is shown. Figure 6

[0035] Referring to Figure 6 and Figure 11 , the central focused beam 106 can have an energy that increases inwardly. In an embodiment, the central focused beam 106 can have a first energy portion 105 and a second energy portion 107.

[0036] The first energy portion 105 can be provided around the second energy portion 107. The first energy portion 105 can have a ring-shaped cross-section. The first energy portion 105 can have a lower energy density than the energy density of the second energy portion 107. The first energy portion 105 of the central focused beam 106 can be provided to an edge portion of the first modified pattern 32.

[0037] ​The second energy portion 107 can be within the first energy portion 105. The second energy portion 107 can have a circular cross-section. The diameter of the second energy portion 107 can be smaller than the diameter of the first energy portion 105. The second energy portion 107 can have a higher energy density than the energy density of the first energy portion 105. The second energy portion 107 of the central focused beam 106 can be provided to a central portion of the first modification pattern 32. The second energy portion 107 of the central focused beam 106 can be provided into the substrate W in the third direction Z perpendicular to the substrate W.

[0038] The first energy portion 105 and the second energy portion 107 of the central focused beam 106 can heat the substrate W at the first focal point 122 to form the first modification pattern 32 in a portion of the substrate W located near the first focal point 122.

[0039] Referring back to Figure 4 and Figure 6 , the first modification pattern 32 can be formed to be arranged in the first direction X. The first modification pattern 32 can be uniformly spaced apart from each other by a first center-to-center distance Dl of about 6 μm to about 10 μm. The first modification pattern 32 can be spaced apart from each other by a distance of about 2 μm or can be in contact with each other.

[0040] Referring to Figure 5 , Figure 7 and Figure 10 , the second laser device 200 can provide the edge focused beam 206 to an upper portion of the substrate W proximate to the thin film 10 along the second direction Y, as a result, the second modification pattern 34 can be formed in the substrate W (in S214). The second laser device 200 can generate the edge focused beam 206 from the second laser beam 202. In an embodiment, the second laser device 200 can include a second light source 210, a plurality of axicon lenses 230, and a second objective lens 220.

[0041] The second light source 210 can generate the second laser beam 202. The second light source 210 can include, for example, a laser diode. The second laser beam 202 can be the same as the first laser beam 102. The second laser beam 202 can have a power in a range of about 0.5 W to about 2.5 W and / or a corresponding energy. The second laser beam 202 can be a collimated beam. The second laser beam 202 can be provided in the form of the second pulse 204. The second pulse 204 can have a pulse frequency of about 100 KHz. The second laser beam 202 can pass through the substrate W. The second laser beam 202 can have a wavelength of about 1100 nm.

[0042] An axicon lens 230 can be disposed between the second light source 210 and the second objective lens 220. The axicon lens 230 can generate the edge-focused beam 206 from the second laser beam 202. In an embodiment, the axicon lens 230 can include a first axicon lens 232 and a second axicon lens 234. The first axicon lens 232 and the second axicon lens 234 can be disposed to face each other. Alternatively, the first axicon lens 232 and the second axicon lens 234 can be disposed to face away from each other.

[0043] The first axicon lens 232 can be disposed between the second light source 210 and the second axicon lens 234. The first axicon lens 232 can be transparent to the second laser beam 202, and thus the second laser beam 202 can be provided to the second axicon lens 234 through the first axicon lens 232. In an embodiment, the first axicon lens 232 can have a first flat surface 231 and a first inclined surface 233. The first flat surface 231 can be perpendicular to the optical axis 208 of the second laser beam 202. The first flat surface 231 can have a diameter Dl of about 14 mm. The first inclined surface 233 can be disposed between the first flat surface 231 and the second axicon lens 234. The first inclined surface 233 can have a first inclined angle θ1 with respect to the optical axis 208 of the second laser beam 202. The first inclined surface 233 can be configured to refract the second laser beam 202 to the second axicon lens 234.

[0044] The second axicon lens 234 can be disposed between the first axicon lens 232 and the second objective lens 220. The second axicon lens 234 can be disposed between a focal point of the first axicon lens 232 and the second objective lens 220. The second axicon lens 234 can be placed outside the focal point of the first axicon lens 232. The second laser beam 202 passing through the second axicon lens 234 can serve as the edge-focused beam 206. The second axicon lens 234 can have a second flat surface 235 and a second inclined surface 237. The second flat surface 235 can be perpendicular to the optical axis 208 of the second laser beam 202. The second flat surface 235 can be parallel to the first flat surface 231 and have the same diameter Dl as the first flat surface 231. The second flat surface 235 can have a diameter Dl of about 14 mm. The second inclined surface 237 can have a second inclined angle θ2 with respect to the optical axis 208 of the second laser beam 202. The second inclined angle θ2 can be equal to the first inclined angle θ1. For example, the first flat surface 231 can be spaced apart from the second flat surface 235 by a third distance D3 of about 15 mm.

[0045] Figure 12 An example of the edge-focused beam 206 is illustrated. Figure 7

[0046] Referring to Figure 12 ​The edge-focused light beam 206 can have a ring shape. An empty area 209 having negligible light energy can be formed in the edge-focused light beam 206. The size or area of the edge-focused light beam 206 and the empty area 209 can change depending on the first tilt angle θ1 and / or the second tilt angle θ2.

[0047] Referring back to Figure 7 The second objective lens 220 can be disposed between the second axicon lens 234 and the substrate W. The second objective lens 220 can be configured to have substantially the same features as the first objective lens 120. The second objective lens 220 can have a numerical aperture (NA) of about 0.8. The second objective lens 220 can be used to provide the edge-focused light beam 206 to the bottom surface of the substrate W. The second objective lens 220 can focus the edge-focused light beam 206 in the substrate W. The second objective lens 220 can have a second focal point 222. The edge-focused light beam 206 can heat the substrate W at the second focal point 222 to form a second modification pattern 34 in the vicinity of the second focal point 222.

[0048] Referring to Figure 5 and Figure 7 The second modification pattern 34 can be formed between the second objective lens 220 and the second focal point 222. The second modification pattern 34 can be formed to have a third height h3 spaced apart from the thin film 10 by about 5 μm to about 10 μm. The second focal point 222 can be adjusted to a position having a fourth height h4 spaced apart from the thin film 10 by about 2 μm to about 3 μm. When viewed in a plan view, the first modification pattern 32 and the second modification pattern 34 can contact each other at a position adjacent to a corner of the active area 12.

[0049] In an embodiment, the edge-focused light beam 206 can be provided to an area around the first modification pattern 32 to form the second modification pattern 34 in contact with the first modification pattern 32. If the first tilt angle θ1 of the first axicon lens 232 and the second tilt angle θ2 of the second axicon lens 234 are adjusted, the edge-focused light beam 206 can be irradiated to an area outside the first modification pattern 32 and can be provided to the second focal point 222. The second focal point 222 can be located below the first modification pattern 32. The edge-focused light beam 206 can be provided to an area intersecting the first modification pattern 32, for example, an area extending in the second direction Y, to form the second modification pattern 34 in contact with the first modification pattern 32 at a position adjacent to a corner of the active area 12.

[0050] Figure 13 The energy of the edge-focused light beam 206 provided to the second focal point 222 is shown with respect to Figure 7 the first tilt angle θ1 and the second tilt angle θ2.

[0051] Referring to Figure 13The energy of the edge-focused beam 206 provided to the second focal point 222 can vary depending on the first tilt angle θ1 and the second tilt angle θ2. For example, in the case where the first tilt angle θ1 and the second tilt angle θ2 are about 51.3°, the edge-focused beam 206 can have the highest energy. In other words, when the axicon lens 230 is provided to have the first tilt angle θ1 and the second tilt angle θ2 of about 51.3°, the second modification pattern 34 in contact with the first modification pattern 32 can be efficiently formed.

[0052] Referring back to Figure 5 , the second modification pattern 34 can be formed to be spaced apart from each other by a constant distance (e.g., a second center-to-center distance D2). In an embodiment, the second center-to-center distance D2 can be in a range of about 6 μm to about 10 μm. The second modification pattern 34 can be spaced apart from each other by a distance of about 2 μm or can be in contact with each other.

[0053] By contrast, when the second modification pattern 34 is formed by the first laser device 100 instead of the second laser device 200, the second modification pattern 34 can not be regularly formed at the second center-to-center distance D2. If the center-focused beam 106 is provided to the second focal point 222, the second energy portion 107 of the center-focused beam 106 can be absorbed by the first modification pattern 32, and thus, the second modification pattern 34 can not be formed in a desired manner. That is, it can be difficult to form the second modification pattern 34 in contact with the first modification pattern 32.

[0054] Figure 14 The first energy 140 of the center-focused beam 106 and the second energy 240 of the edge-focused beam 206 provided to the second focal point 222 of the second laser device 200 are shown. Figure 7 The horizontal axis represents a moving distance of the second focal point 222 in the second direction Y, and the vertical axis represents the normalized energy.

[0055] Referring to Figure 14 The second energy 240 of the edge-focused beam 206 provided to the second focal point 222 can be higher than the first energy 140 of the center-focused beam 106. For example, the second energy 240 can be about 40% or more higher than the first energy 140. The first energy 140 can correspond to the energy of the second energy portion 107 of the center-focused beam 106. The second energy portion 107 of the center-focused beam 106 can be absorbed by the first modification pattern 32 and can be lost. The edge-focused beam 206 can be provided to the second focal point 222 without loss due to absorption by the first modification pattern 32. Thus, the edge-focused beam 206 can heat the substrate W at the second focal point 222, and the second modification pattern 34 can be formed in the vicinity of the second focal point 222. The second modification pattern 34 can be in contact with the first modification pattern 32.

[0056] Figure 15 A typical modification pattern 36 formed by the center-focused light beam 106 is shown. Figure 6 A typical modification pattern 36 formed by the center-focused light beam 106 is shown.

[0057] Referring to Figure 15 A typical modification pattern 36 formed by the center-focused light beam 106 can not be in contact with the first modification pattern 32. The typical modification pattern 36 can be formed at an irregular distance without being in contact with the first modification pattern 32. Due to the irregular distance between the typical modification patterns 36, the typical modification patterns 36 can cause a dicing crack damage 38 when the substrate W is stretched. In addition, the dicing crack damage 38 can cause damage to the active area 12.

[0058] Referring back to Figure 7 The edge-focused light beam 206 can be used to form the second modification pattern 34 without interfering with the first modification pattern 32. The edge-focused light beam 206 can be used to regularly form the second modification pattern 34 at the corners of the active area 12, in which case the dicing crack damage 38 can be limited and / or prevented.

[0059] Referring to Figure 3 and Figure 8 The polishing apparatus 300 can be configured to grind a bottom surface of the substrate W and thin the substrate W (in S220). The polishing apparatus 300 can include a grinder or a chemical mechanical polishing apparatus. The thinned substrate W can have a thickness in a range of about 50 pm to about 250 pm.

[0060] Referring to Figure 3 and Figure 9 The stretcher can stretch the substrate W to separate the semiconductor chips C from each other (in S230). The stretcher can stretch the substrate W using the tape film 40. The tape film 40 can be adhered to the bottom surface of the substrate W. The stretcher can stretch the tape film 40 in the first direction X and the second direction Y to separate the semiconductor chips C from each other. The semiconductor chips C can be singulated along the first modification pattern 32 and the second modification pattern 34 in the dicing street 20. Thereafter, the semiconductor chips C can be separated from the tape film 40 using a pick-up.

[0061] Figure 16 An example of the semiconductor chip C of Figure 9 is shown.

[0062] Referring to Figure 16 The semiconductor chip C can have a rectangular box shape. In an embodiment, the semiconductor chip C can include the substrate W and the thin film 10.

[0063] The substrate W can be formed of or include single-crystal silicon. The substrate W can have a first side surface 52 and a second side surface 54 between a top surface and a bottom surface thereof, and a corner 56. The first side surface 52 can be parallel to the first direction X. The second side surface 54 can be parallel to a direction intersecting the first side surface 52. For example, the second side surface 54 can be parallel to the second direction Y. The corner 56 can be between the first side surface 52 and the second side surface 54, and can be parallel to the third direction Z. The corner 56 can be an intersection line of the first side surface 52 and the second side surface 54. As an example, the substrate W can have a modification pattern 30. The modification pattern 30 can be disposed in the substrate W. The modification pattern 30 can have an ellipsoidal shape elongated in the third direction Z. The modification pattern 30 can have a thickness T of about 20 pm and a width WD of about 1.5 pm to 5 pm. In an embodiment, the modification pattern 30 can include a first modification pattern 32 and a second modification pattern 34.

[0064] The first modification pattern 32 can be formed in the first side surface 52 parallel to the first direction X and in the corner 56. The first modification pattern 32 can be spaced apart from each other by a distance of about 2 pm or less in the first direction X, or can be in contact with each other.

[0065] The second modification pattern 34 can be formed in the second side surface 54 parallel to the second direction Y and in the corner 56. The second modification pattern 34 can be spaced apart from each other by a distance of about 2 pm or less in the second direction Y, or can be in contact with each other. In an embodiment, the first modification pattern 32 and the second modification pattern 34 can be in contact with each other at the corner 56.

[0066] The thin film 10 can be disposed on the substrate W. The thin film 10 can be disposed on the top surface of the substrate W. The thin film 10 can be a remaining portion of a semiconductor device other than the substrate W. For example, the thin film 10 can include a volatile memory device such as a DRAM chip, a non-volatile memory device such as a 3D NAND FLASH memory chip, or a semiconductor device such as a logic device.

[0067] Figure 17 Another example of the operation S200 of cutting the substrate W is illustrated. Figure 2

[0068] Referring to Figure 17 , the cutting of the substrate W (in S200) can include polishing a bottom surface of the substrate W (in S220), forming the modification pattern 30 (in S210), and stretching the substrate W to form the semiconductor chip C (in S230). In an embodiment, the polishing of the bottom surface of the substrate W (in S220) can be performed before the forming of the modification pattern 30 (in S210). The stretching of the substrate W to form the semiconductor chip C (in S230) can be performed in the same manner as the cutting of the substrate W (in S200) with reference to​Figure 3 is performed in the same manner as described.

[0069] According to an embodiment of the inventive concept, the substrate cutting method can include regularly forming a modification pattern at a corner of the active area using an edge-focused light beam provided to an area intersecting a part of the modification pattern that has already been formed, which makes it possible to limit and / or prevent a cutting crack from being damaged.

[0070] While example embodiments of the inventive concept have been particularly shown and described, those of ordinary skill in the art will understand that changes can be made in form and detail without departing from the spirit and scope of the appended claims.

[0071] This application claims priority to Korean Patent Application No. 10-2019-0151826, filed on November 25, 2019, in the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

Claims

1. A method for cutting a substrate, comprising: A modified pattern is formed in a scribe line of a substrate using a laser beam, the scribe line extending in a first direction and a second direction intersecting the first direction. Forming the modified pattern includes: forming a plurality of first modified patterns at a first depth within the substrate by intermittently providing a centrally focused beam along a portion of the scribe line in the first direction; and forming a plurality of second modified patterns at a second depth within the substrate at the same depth as the first depth by intermittently providing an edge-focused beam along another portion of the scribe line in the second direction. The plurality of first modified patterns have a regular first spacing, a first circular shape in a first plane defined by the first and second directions, and a first ellipsoidal shape in a third direction intersecting the first and second directions. The plurality of second modified patterns have a regular second spacing, a second circular shape in the first plane identical to the first circular shape, and a second ellipsoidal shape in the third direction identical to the first ellipsoidal shape. Wherein, at the position where the first direction and the second direction intersect, the second modified pattern contacts the first modified pattern; Grinding the bottom surface of the substrate to thin the substrate; and Extend the substrate to divide it into multiple dies. The focal point of the edge-focused beam is located within the substrate.

2. The method of claim 1, wherein the edge-focused beam is generated by a plurality of axial conical lenses.

3. The method according to claim 2, wherein Forming the modified pattern includes focusing the edge-focused beam at a location on the substrate using an objective lens, and The plurality of axial cone lenses includes a first axial cone lens and a second axial cone lens. The first axial cone lens has a first flat surface and a first inclined surface on the first flat surface. The second axial-cone lens is provided between the first axial-cone lens and the objective lens, and The second axial cone lens has a second flat surface and a second inclined surface on the second flat surface.

4. The method according to claim 3, wherein the first inclined surface and the second inclined surface have an inclination angle of 51.3°.

5. The method of claim 3, wherein the first inclined surface and the second inclined surface face each other.

6. The method according to claim 3, wherein the first flat surface and the second flat surface are spaced apart by a distance of 15 mm.

7. The method of claim 3, wherein each of the first flat surface and the second flat surface has a diameter of 14 mm.

8. The method according to claim 1, wherein Forming the second modified pattern involves setting the focal point of the edge-focused beam at a lower height than the bottom of the first modified pattern.

9. The method of claim 1, wherein the first modified pattern and the second modified pattern are formed as elongated spheres.

10. A method for cutting a substrate, comprising: A plurality of first modified patterns are formed at a first depth in a portion of the scribe groove of the substrate using a centrally focused beam intermittently provided by a first laser device in a first direction of the scribe groove. Using an edge-focused beam intermittently provided by a second laser device in a second direction intersecting the first direction of the scribe groove, a plurality of second modified patterns are formed in another portion of the scribe groove on the substrate at a second depth equal to the first depth. The plurality of first modified patterns have a regular first spacing, a first circular shape in a first plane defined by the first and second directions, and a first ellipsoidal shape in a third direction intersecting the first and second directions. The plurality of second modified patterns have a regular second spacing, a second circular shape in the first plane identical to the first circular shape, and a second ellipsoidal shape in the third direction identical to the first ellipsoidal shape. Where the second modified pattern comes into contact with the first modified pattern at the position where the first direction and the second direction intersect. The second laser device includes a light source, an objective lens, a first axial cone lens, and a second axial cone lens. The light source is configured to generate a laser beam. The objective lens is located between the light source and the substrate. The first axial-cone lens and the second axial-cone lens are located between the objective lens and the light source. The first and second axial-cone lenses are configured to generate the edge-focused beam from the laser beam, wherein the focal point of the edge-focused beam is within the substrate. The first axial cone lens and the second axial cone lens each include a first inclined surface and a second inclined surface, and the first inclined surface and the second inclined surface are inclined at an angle of 51.3° relative to the optical axis of the laser beam; as well as Extend the substrate to divide it into semiconductor chips.

11. The method of claim 10, wherein The first axial cone lens and the second axial cone lens further include a first flat surface and a second flat surface, respectively, the first flat surface and the second flat surface being located on the first inclined surface and the second inclined surface, respectively. Each of the first flat surface and the second flat surface has a diameter of 14 mm.

12. The method of claim 11, wherein The first inclined surface and the second inclined surface face each other, and The first flat surface and the second flat surface are spaced 15 mm apart.

13. The method of claim 10, wherein the light source is configured to generate a laser beam having a pulse frequency of 100 kHz and a wavelength of 1100 nm.

14. The method of claim 10, further comprising: The substrate is ground to reduce its thickness.

15. A method for manufacturing a semiconductor device, comprising: A thin film is formed on the substrate; as well as The substrate is cut to divide it into multiple semiconductor chips. The dicing of the substrate includes forming a modified pattern in scribe lines on the substrate using a laser beam, grinding the bottom surface of the substrate to thin it, and stretching the substrate to divide it into the plurality of semiconductor chips. The scribe lines extend in a first direction and in a second direction intersecting the first direction. Forming the modified pattern includes: forming a plurality of first modified patterns in the substrate at a first depth by intermittently providing a centrally focused beam along a portion of the scribe line in the first direction; and forming a plurality of second modified patterns in the substrate at a second depth equal to the first depth by intermittently providing an edge-focused beam along another portion of the scribe line in the second direction. The plurality of first modified patterns have a regular first spacing, a first circular shape in a first plane defined by the first and second directions, and a first ellipsoidal shape in a third direction intersecting the first and second directions. The plurality of second modified patterns have a regular second spacing, a second circular shape in the first plane identical to the first circular shape, and a second ellipsoidal shape in the third direction identical to the first ellipsoidal shape. The second modified patterns contact the first modified patterns at the locations where the first and second directions intersect. The focal point of the edge-focused beam is located within the substrate.

16. The method of claim 15, wherein The thin film includes active and non-active regions. The active region is located near the central region of the substrate. The non-active region is located in the edge region of the substrate and outside the active region.

17. The method of claim 16, wherein the active region comprises a semiconductor device.

18. The method of claim 15, wherein the focal point of the edge-focused beam is set at a lower height than the bottom of the first modified pattern.

19. The method of claim 15, wherein the first modified pattern and the second modified pattern are formed as elongated spheres.

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