Dicing method

Abstract

To provide an improved cutting and breaking method suitable for scribing hard materials such as SiC, even at relatively large thicknesses, and particularly for breaking materials with a metallized layer, especially one having a metallized layer with a thickness between approximately 0.5 and 5 μm. [Solution] A method for breaking a substantially planar workpiece having first and second main surfaces, with a metallized layer on the first main surface, i) A step of forming a groove in a workpiece that extends parallel to a plane, the groove being open on the upper surface of the workpiece, and subsequently ii) Applying a workpiece breaking force to the first main surface of the workpiece to split the workpiece along a fracture line that coincides with a groove, and then iii) A step of applying a metallic fracture force to the second main surface of the workpiece to fracture the metallized layer along the fracture line, Includes.

Description

Technical Field

[0001] The present invention relates to a method for breaking a substantially planar workpiece having first and second major surfaces and provided with a metallization layer on the first major surface, and a method for scribing a substantially planar workpiece.

Background Art

[0002] Singulation and scribing are well-known processes in the semiconductor industry, and, for example, but not limited to this, a cutting machine is used to process workpieces or substrates such as semiconductor wafers, which may include silicon, or metal and / or ceramic wafers. Throughout this specification, the term "wafer" is used to encompass all these products. In the singulation process (also called, for example, dicing, sawing, scribing), the wafer is completely cut to individualize, for example, the wafer into individual dies or chips. In the scribing process (also called, for example, grooving, scoring, gouging or channeling), channels or grooves are cut into the wafer. Other processes, for example, by using a physical saw along the cut channels, can subsequently be applied for complete singulation.

[0003] Silicon carbide (SiC) is an emerging substrate material replacing silicon for high-power electronics applications. For many applications, SiC offers excellent performance due to its high-temperature and high-voltage performance compared to standard silicon devices.

[0004] Because SiC is almost as hard as diamond, separating wafers into individual chips is a difficult process. Currently, mechanical blade dicing is the most widely used method for dicing SiC wafers. However, such blade dicing suffers from very low feed rates, poor edge quality, and rapid wear of the dicing blades. As the use of 150mm or even 200mm SiC wafers becomes more standard, blade dicing will likely reach its limits due to these drawbacks.

[0005] For thin SiC wafers (less than approximately 150 micrometers thick), laser ablation is a good alternative to mechanical blades because it can achieve sufficient quality and significantly improve throughput. In the laser ablation process, the removal of semiconductor material occurs because the rapid temperature rise of a relatively small area where the laser beam is concentrated causes the localized material to melt, explosively boil, evaporate, and be removed. Laser singulation has challenging requirements, including a delicate balance between process throughput and workpiece (die) quality. Process quality and throughput are determined by laser parameters such as fluence, pulse width, repetition rate, and wavelength.

[0006] However, for thicker SiC wafers (approximately 150-350 micrometers thick), there is still no good alternative to mechanical blades, especially for applications where the mechanical die strength of individual chips is critical. Laser ablation for such wafers also suffers from very low throughput and increasingly poor quality. In addition, the mechanical die strength that can be obtained with laser ablation is limited and difficult to meet current requirements.

[0007] The laser scribe-and-break approach is well known. In this process, a laser is used to create weak lines in the wafer, and then a mechanical fracturing action is applied to break the wafer along these weak lines. This process is schematically shown in Figures 1 and 2.

[0008] Figure 1 schematically shows, from top to bottom, a substantially planar wafer 1 scribable using a laser scribing process. As shown in the figure, the wafer 1 contains a plurality of electronic devices 2, which are arranged in a regular array such that straight channels extend between the devices 2. An incident laser directed towards the top surface of the wafer is used to form scribe lines 3 along these channels, so that each device 2 is separated from its adjacent devices 2 by the scribe lines 3.

[0009] Figure 2 schematically shows wafer 1 from a side view, which is to be mechanically fractured in a manner known in the art. For clarity, device 2 is omitted. In this figure, it can be seen that wafer 1 is bonded on its underside to a flexible sheet 4 known as a dicing tape. Wafer 1 and flexible sheet 4 are held within a frame (not shown for clarity). The assembly of wafer 1 and sheet 4 is supported on a rigid support assembly or anvil 5. This support assembly 5 can be used to support wafer 1 during scribing, or wafer 1 can be placed on a chuck (not shown) during scribing and then moved to such a support assembly 5 following completion of scribing.

[0010] In Figure 2, wafer 1 is fractured by mechanically pressing down on the top surface of wafer 1 using, for example, a blade or chisel 6 as shown, and splitting wafer 1 along a scribe line 3 that is weaker than the surrounding wafer material.

[0011] However, these processes also have drawbacks with SiC, particularly in that the mechanical die strength is relatively weak.

[0012] Furthermore, current laser scribe-and-break methods are not suitable for breaking substrates that have a metallized layer on one of their main surfaces. For such substrates, it is generally required to cut the metallized layer mechanically or by laser. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] U.S. Patent No. 9120178B2 [Overview of the project] [Problems that the invention aims to solve]

[0014] The present invention seeks to provide an improved cutting and breaking method suitable for scribing hard materials such as SiC, even at relatively large thicknesses, and particularly for breaking materials having a metallized layer, especially one having a metallized layer with a thickness between approximately 0.5 and 5 μm.

[0015] According to the present invention, this objective is achieved by using a laser scribing device to scribe a specially formed scribe line or groove into a workpiece, the scribe line forming a weak line in the workpiece, thereby enabling subsequent fracture of the workpiece.

[0016] In one embodiment, scribe lines or grooves are produced using a combination of different scribing modes, particularly a first mode that creates relatively deep and narrow grooves, and a second mode that removes heat-affected material from areas of the workpiece adjacent to the top of the grooves. In another embodiment, a workpiece with a metallized layer can be fractured by applying a series of mechanical fracture steps to each major surface of the workpiece following the application of the scribing process. [Means for solving the problem]

[0017] According to a first aspect of the present invention, there is provided a method for breaking a substantially planar workpiece having first and second major surfaces and provided with a metallization layer on the first major surface, which comprises: i) forming a groove extending parallel to the plane in the workpiece, the groove being open at the upper surface of the workpiece; and subsequently ii) applying a workpiece breaking force to the first major surface of the workpiece to split the workpiece along a breaking line coinciding with the groove; and then iii) applying a metal breaking force to the second major surface of the workpiece to break the metallization layer along the breaking line. The method includes the above steps.

[0018] According to a second aspect of the present invention, there is provided a method for scribing a substantially planar workpiece, which comprises: i) moving the workpiece relative to an incident laser beam while irradiating the workpiece with a first irradiation pattern of the incident laser beam to form a groove extending parallel to the plane in the workpiece, the groove being open at the upper surface of the workpiece and having a first cross-sectional shape with a first depth d1; and subsequently ii) moving the workpiece relative to the incident laser beam while irradiating the workpiece with a second irradiation pattern of the incident laser beam to modify the upper portion of the groove, the upper portion having a depth d2 where d2 < d1, and creating a modified groove having a second cross-sectional shape different from the first cross-sectional shape. The method includes the above steps.

[0019] Other specific aspects and features of the present invention are defined in the appended claims.

[0020] Next, the present invention will be described with reference to the accompanying drawings (not to scale).

Brief Description of the Drawings

[0021] [Figure 1] Schematically shows a wafer scribed using a laser from above. [Figure 2] Schematically shows the wafer of FIG. 1 from the side, with the preparation for the breaking step being ready. [Figure 3] Schematically shows an exemplary laser scribing apparatus for performing the laser scribing method according to the present invention from the side. [Figure 4] Schematically shows a part of the wafer when it is first being scribed according to an embodiment of the present invention from above. [Figure 5] Schematically shows a part of the wafer when it is first being scribed according to an alternative embodiment of the present invention from above. [Figure 6] Schematically shows the groove created according to the first scribing in a cross-sectional side view. [Figure 7] Schematically shows a part of the wafer when it is subsequently being scribed according to an embodiment of the present invention from above. [Figure 8] Schematically shows the scribe line created according to the subsequent scribing from the side. [Figure 9] Schematically shows a part of the wafer being scribed according to an embodiment of the present invention from above. [Figure 10] Schematically shows a part of the wafer being scribed according to an alternative embodiment of the present invention from above. [Figure 11] Schematically shows a wafer with a composite metallization layer in a cross-sectional side view. [Figure 12] Schematically shows the scribing sub-process of the breaking method according to the present invention. [Figure 13] Schematically shows the breaking sub-process of the breaking method. [Figure 14] Schematically shows an apparatus configured to break the wafer during the breaking sub-process from the side. [Figure 15] Schematically shows an apparatus configured to break the metallization layer during the breaking sub-process from the side.

Embodiments for Carrying Out the Invention

[0022] A first embodiment of the present invention relating to a scribing process suitable for SiC workpieces with or without a metallized layer is described below with reference to Figures 3 to 10. When scribing according to the present invention, the workpiece will look from above similar to that shown in Figure 1 and can be mechanically fractured using a process similar to that shown in Figure 2. Therefore, reference figures are retained from these figures as far as possible.

[0023] According to this embodiment of the present invention, when the wafer 1 is subjected to the mechanical fracture process as described above, a scribe line 3 that acts as a weak line to preferentially fracture is formed by a two-part scribing process. In the first part of the process, a relatively narrow and deep groove (18, see Figure 6) is formed, while in the second part of the process, the first groove 18 is modified to remove heat-affected material from around the upper region of the groove 18.

[0024] Figure 3 schematically shows an exemplary laser scribing apparatus used when performing the laser scribing method of the present invention, viewed from the side.

[0025] A laser source 11 is configured to output a laser beam 12, which is directed towards the wafer 1 via first and second mirrors 13, 14 along the optical path. A beam shaper 15, such as a diffractive optical element (DOE) or spatial light modulator, is placed in the optical path to create an irradiation pattern of incident laser light, including a sub-beam 16 on the wafer 1, as will be described in more detail below. The laser source 11 is selected such that the resulting laser beam 12 is capable of cutting through the material of the wafer 1. For example, a suitable laser source 11 can generate a laser beam with a wavelength in the range of approximately 300 to 380 nm, optionally in the range of approximately 330 to 370 nm, with a pulse duration of approximately 10 ns to 250 ns at approximately 10 to 100 kHz, or approximately 0.1 ps to 10 ps at approximately 100 to 2000 kHz, and an output power in the range of approximately 0.1 W to 10 W. In this embodiment, the wafer 1 and the flexible sheet 4 are supported on a chuck 10 that is drivable in the horizontal (XY) plane, as indicated by the large arrows. The laser assembly, i.e., the laser source 11, mirrors 13, 14 and beam shaper 15, is held stationary, while the chuck 10 moves the wafer 1 relative to the incident laser beam. This relative movement in the translational direction while the wafer 1 is irradiated by the incident laser beam acts to cut the wafer material along a line on the upper surface 19 of the wafer 1 parallel to the translational direction.

[0026] In other embodiments (not shown), the wafer 1 can be held stationary while the laser beam is translated, or both the wafer 1 and the laser beam are translated.

[0027] Scribing techniques that use irradiation patterns obtained from beam shapers such as DOEs are known, for example, from Patent Document 1.

[0028] The first part of the process, namely the initial scribing which creates a relatively deep and narrow groove 18 on the upper surface 19 of the wafer 1, will now be described with reference to Figures 4 to 6.

[0029] More specifically, this first part of the process involves irradiating the wafer 1 with a first irradiation pattern of incident laser light while moving the wafer 1 in a translational direction relative to the incident laser light to form a groove 18 (see Figure 6) in the wafer 1 that extends parallel to its plane, the groove 18 opening on the upper surface 19 of the wafer 1 and having a first cross-sectional shape with a first depth d1.

[0030] Figure 4 schematically shows, from top to bottom, a portion of wafer 1 as it is being initially scribed according to one embodiment of the present invention. As shown, the beam shaper 15 (see Figure 3) is configured to create a first irradiation pattern in which a linear array of spatially separated laser subbeams, separated from the laser beam 12, irradiates a plurality of spots 17 onto the upper surface of wafer 1. In this regard, the term “linear array” is used to describe a pattern in which the maximum number of spots 17 irradiating wafer 1 does not change along the length of the direction of relative motion between wafer 1 and the laser assembly, as indicated by the large arrows in Figure 4, and the positions of these spots in a direction perpendicular to this direction also do not change. In the example shown in Figure 4, the linear array has a single subbeam in a direction perpendicular to the translational direction (i.e., creating a single spot 17) and four subbeams extending along a line parallel to the translational direction (i.e., creating four corresponding spots 17). This irradiation pattern cuts a relatively narrow area of ​​the wafer material, creating a relatively narrow and deep groove 18 on the upper surface 19 of wafer 1.

[0031] Figure 5 shows a first irradiation pattern according to an alternative embodiment of the present invention, in which the linear arrangement of laser subbeams has two subbeams in a direction perpendicular to the translational direction (i.e., creating two spots 17) and four subbeams extending along a line parallel to the translational direction (i.e., creating four spots 17).

[0032] Other forms of the first irradiation pattern are also possible.

[0033] FIG. 6 is a cross-sectional side view schematically showing the groove 18 generated during this initial scribing process. By using a linear array of sub-beams, a groove 18 having a substantially V-shaped profile that opens at the upper surface 19 is created. As shown, the groove 18 has a cross-sectional shape with a maximum depth d1. The maximum width w1 of the groove 18 is at the upper surface 19. When the wafer 1 has a thickness in the range of 100 to 350 μm, the groove 18 can advantageously have a depth in the range of 5 to 60 μm. Optionally, the wafer 1 has a thickness in the range of 100 to 200 μm, the groove 18 has a depth in the range of 5 to 15 μm, and optionally, the wafer 1 has a thickness in the range of 200 to 350 μm, and the groove 18 has a depth in the range of 40 to 60 μm.

[0034] According to this aspect of the invention, when the groove 18 is formed, while irradiating the wafer 1 with a second irradiation pattern of incident laser light, the wafer 1 is moved with respect to the incident laser light in a direction parallel to the translational direction to modify the upper part of the groove 18, the upper part having a depth d2, where d2 < d1, and a subsequent process is performed that includes creating a modified groove 20 having a second cross-sectional shape different from the first cross-sectional shape. This modification acts to remove a portion of the wafer 1 near the upper part of the groove 18 that is susceptible to thermal damage during the initial scribing process. This preferably includes the so-called "heat-affected zone" (HAZ) of the wafer 1.

[0035] FIG. 7 schematically shows a part of the wafer 1 when it is subsequently being scribed according to an embodiment of the invention from above, while FIG. 8 schematically shows the modified groove 20 created by this subsequent scribing from the side.

[0036] In this embodiment, the second irradiation pattern is arranged in a V-shaped pattern such that the width of the pattern, which is orthogonal to the translation direction, increases in the translation direction (the translation direction is indicated by the large arrow), and includes a plurality of sub-beams (i.e., creating corresponding spots 21). This V-shape has its base on the leading side of the second irradiation pattern. The second irradiation pattern includes a plurality of pairs of sub-beams spaced parallel to the translation direction (i.e., spaced parallel to the X direction shown in the figure), and each pair includes a first and a second sub-beam spaced in a horizontal direction orthogonal to the translation direction (i.e., spaced parallel to the Y direction shown in the figure). It can also be seen that the spacing (parallel to the Y direction) between the first and second sub-beams of each pair increases in the translation direction.

[0037] This V-shaped profile acts on a relatively wide and shallow region of the wafer 1 to create the composite modified groove profile schematically shown in FIG. 8. Here, the original groove 18 created by the first process is modified, and more specifically, the upper part of the groove 18 is modified such that the upper part has a depth d2, where d2 < d1, and it can be seen that a modified groove 20 with a second cross-sectional shape different from the cross-sectional shape of the groove 18 is generated. The maximum width of the modified groove 20 disposed on the upper surface of the wafer 1 is w2, where w2 > w1 (see FIG. 7). As described above, this modification affects the upper part of the groove 18 but leaves the lower part of the groove 18 unaffected, and a relatively deep and narrow valley 22 extends downward into the body of the wafer 1 as shown in FIG. 8. This valley 22 is beneficial in subsequent mechanical breaking processes to create a distinct weak line.

[0038] In a preferred embodiment, the same laser scribing apparatus (such as that shown in FIG. 3) can be used to perform both the first and second parts of the process outlined above. In this case, there are two main possibilities. i) Using a first beam shaper to generate a first irradiation pattern and create grooves 18 in wafer 1 in a first part of the process, then replacing beam shaper 15 with a different beam shaper positioned in the optical path to create a second irradiation pattern, and translating wafer 1 again relative to the laser assembly so that the second irradiation pattern modifies the grooves 18, or ii) A single beam shaper 15 is provided that operates to split the laser beam into first and second laterally spaced irradiation patterns (i.e., to create a relatively complex composite irradiation pattern), the first irradiation pattern forming grooves 18 in the wafer 1, and immediately afterward correcting the grooves 18 with the second irradiation pattern.

[0039] However, two separate laser scribing devices can be used equally, each performing one of the first and second parts of the process, with each laser scribing device equipped with a dedicated beam shaper for performing each part of the process. By physically placing the wafer 1, on which the groove 18 has been formed using the first laser scribing device, into the second laser scribing device, the groove 18 can be modified.

[0040] Figure 9 schematically shows, from top to bottom, a portion of wafer 1 being scribbled according to one embodiment of the present invention using separate scribing operations for each of the first and second parts of the process. As described above, this can be achieved by using the same laser scribing apparatus but with different beam shapers, or by using two separate laser scribing apparatuses.

[0041] Figure 10 schematically shows, from top to bottom, a portion of a wafer being scribbled according to an alternative embodiment of the present invention, in which the modified groove 20 is formed in a single scribing operation within a single laser scribing apparatus. In this case, a single, more complex beam shaper is used, which can create a composite irradiation pattern 23 of subbeams, including a V-shaped subbeam contour, following a linear arrangement of subbeams.

[0042] Following the creation of all required modified grooves 20, the wafer 1 can be mechanically fractured using the method described with respect to Figure 2 or a similar alternative.

[0043] A second embodiment of the present invention relating to a fracture process suitable for a SiC workpiece or wafer having a metallized layer is now described with reference to Figures 11 to 15. It is important to note that this fracture process utilizes laser scribing, while the two-step process described above with reference to the first embodiment is more beneficial, but does not necessarily require such a scribing process. Where possible, similar reference figures are maintained from the previous figures.

[0044] Various forms of metallized layers 60 can be provided on the wafer 1, including composite metallized layers comprising multiple layers of different metallic materials. Figure 11 schematically shows a wafer 1 with an exemplary composite metallized layer 60 in a cross-sectional side view. In this exemplary case, the composite metallized layer 60 includes a Ti layer 70 adjacent to the substrate having a thickness in the range of about 0.01 to 0.1 μm, a Ni or NiV layer 72 adjacent to layer 70 having a thickness in the range of about 0.1 to 0.5 μm, and an Au or Ag layer 74 adjacent to layer 72 having a thickness in the range of about 0.5 to 5 μm. In general, the present invention is not limited thereto, but is particularly applicable to fracturing a metallized layer 60 having a thickness between about 0.5 and 5 μm.

[0045] Figures 12 and 13 illustrate the fracture process as flowcharts, with Figure 12 showing the first part of the process related to the laser scribing subprocess and Figure 13 showing the second part of the process related to the fracture subprocess.

[0046] This process begins at 30, where an unscribed wafer 1, including a metallized layer, a first or lower main surface, is held within a frame 62 (see Figure 14) by layers of dicing tape 64 (see Figure 14), as is well known in the art. Multiple devices 2 are provided on the upper or second main surface. The wafer 1 may, for example, contain silicon carbide (SiC).

[0047] In step 32, the unscribed wafer 1 is covered on its second main surface with a coating, such as a thin layer (on the order of microns) of polymer material, as is commonly known in the art, which acts to prevent the material to be excised during the subsequent step 34 from coming into contact with the wafer 1.

[0048] In step 34, the wafer 1 is scribed using a laser to create at least one groove 18 between the devices 2. This step can be performed using the same or identical apparatus as shown, for example, in Figure 3. More specifically, this step may include forming the groove 18 by moving the wafer 1 in a translational direction relative to the incident laser beam while irradiating the second main surface of the wafer 1 with the incident laser beam. Although not essential, it is particularly effective to create a groove 18 having a contour as described in the previous embodiments with reference to Figures 4 to 10, i.e., first forming a groove with a first cross-sectional shape, and then modifying the top of the groove to generate a modified groove 20 having a second cross-sectional shape different from the first cross-sectional shape. Regardless of the cross-sectional shape of the groove 18, advantageously, if wafer 1 has a thickness in the range of 100 to 350 μm, the groove 18 can have a depth in the range of 5 to 60 μm; optionally, if wafer 1 has a thickness in the range of 100 to 200 μm, the groove 18 can have a depth in the range of 5 to 15 μm; optionally, if wafer 1 has a thickness in the range of 200 to 350 μm, the groove 18 can have a depth in the range of 40 to 60 μm. The incident laser light can advantageously have a wavelength in the range of 300 to 380 nm, optionally in the range of 330 to 350 nm. The incident laser light can advantageously include a pulsed beam with a frequency in the range of 10 to 100 kHz and a pulse duration in the range of 10 to 250 ns. The incident laser light can advantageously include a pulsed beam with a frequency in the range of 100 to 2000 kHz and a pulse duration in the range of 0.1 to 10 ps. The incident laser beam can preferably have an output in the range of 0.1 to 10 W.

[0049] In step 36, the scribed wafer 1 is cleaned to remove any debris resulting from the coating and scribing process performed in step 32. This can be achieved, for example, by rotating the wafer 1 and spraying it with water at high pressure, as is known in the art itself.

[0050] The laser scribing subprocess is completed here, and in step 38, this process moves on to the fracture subprocess, which begins in step 40 (see Figure 13).

[0051] In step 42, a protective film 66 (see Figure 14) is applied to the second main surface of wafer 1. This can be applied in a moderately thin layer, for example less than about 100 μm (such as PVC, PET, PO, or Mylar®), and may include, for example, a non-adhesive, (semi-)transparent plastic film. The protective film 66 is applied for two main reasons. i) To protect the area of ​​action on the wafer that would otherwise come into contact with the support 5, ii) To prevent the adhesive dicing tape 64 from adhering to the support 5 or the blade or chisel 6.

[0052] In step 44, wafer 1 is fractured. More specifically, a wafer fracture force is applied to the first main surface of wafer 1 to break wafer 1 along a fracture line coinciding with the groove 18. More specifically, this step can be performed by placing wafer 1 on the support 5 with the first main surface covered by the metallized layer 60 facing upward, and then applying a wafer fracture force to the first main surface. This fracture step can be advantageously performed as schematically shown, for example, in Figure 14, which shows wafer 1 being supported by the support device 5. A device 2 is provided, and the groove 18 has been scribed according to step 34, the second main surface of wafer 1 is facing downward and protected by a protective film 66. Wafer 1 is thus held within the frame 62, and it can be seen that wafer 1 is covered by the protective film 66 in close proximity to its second main surface and covered by the dicing tape 64 on its first main surface. At this position, wafer 1 is fractured by applying a wafer-fracturing force downward, for example, using a blade or chisel 6, at a location directly overlapping each groove 18. The applied wafer-fracturing force is sufficient to fracture wafer 1, but generally not sufficient to fracture the metallized layer 60. After the wafer 1 is fractured in this manner, fracture lines 68 (see Figure 15) are formed that extend along the entire thickness of wafer 1, following the lines of the corresponding grooves 18. This step can be repeated as required until wafer 1 is fractured along all scribe lines.

[0053] In step 46, the frame 62 containing the wafer 1 is inverted so that the second main surface faces upward, and then in step 48, a metallic breaking force is applied to the second main surface to break the metallized layer 60 as schematically shown in Figure 15. Conveniently, step 48 can be performed using the same apparatus as in step 44. The blade or chisel 6 is aligned with the fracture line 68 and breaks the metallized layer 60 along the line directly adjacent to the fracture line 68. This step is repeated to continuously break the region of the metallized layer 60 adjacent to each fracture line 68.

[0054] In step 50, the protective film 66 applied in step 42 is removed, which can be achieved simply by, for example, pulling it off wafer 1.

[0055] This process can then be terminated in step 52. The wafer 1 is removed from the frame 62 and the dicing tape 64 and can be further used or processed as required.

[0056] The embodiments described above are merely illustrative, and other possibilities and alternatives within the scope of the present invention will be obvious to those skilled in the art. [Explanation of Symbols]

[0057] 1 wafer 2 devices 3 scribelines 4. Flexible Sheet 5. Support Assembly 6 Chisels 10 Chuck 11 Laser source 12 laser beams 13, 14 Miller 15 Beam Shaper 16 Subbeam 17 spots 18 Groove 19 Top side 20 Modified grooves 21 spots 22 Valley 23 irradiation patterns d1 Groove depth w1 Groove width d2 Depth of the modification area w2 Width of the correction area 30 to 52 steps in the flowchart 60 metallization layer 62 frames 64 Dicing Tapes 66 Protective Films 68 Broken line 70 Ti layer 72 Ni / NiV layer 74 Au / Ag layer

Claims

1. A method for breaking a substantially planar workpiece having first and second main surfaces, wherein the first main surface is provided with a metallized layer, i) A step of forming a groove in the workpiece that extends parallel to a plane, wherein the groove is open on the upper surface of the workpiece, and subsequently ii) Applying a workpiece breaking force to the first main surface of the workpiece to break the workpiece along a fracture line that coincides with the groove, and then iii) A step of applying a metal breaking force to the second main surface of the workpiece to break the metallized layer along the fracture line, Methods that include...

2. The method according to claim 1, step i) comprising the step of moving the workpiece in a translational direction with respect to the incident laser beam while irradiating the second main surface of the workpiece with the incident laser beam to form the groove.

3. Step i) is a) A step of irradiating the workpiece with a first irradiation pattern of incident laser light while moving the workpiece in a translational direction relative to the incident laser light to form a groove in the workpiece that extends parallel to a plane, wherein the groove opens on the upper surface of the workpiece and has a first cross-sectional shape with a first depth d1, and subsequently b) While irradiating the workpiece with a second irradiation pattern of incident laser light, move the workpiece relative to the incident laser light in a direction parallel to the translation direction to modify the upper part of the groove, the upper part having a depth d2 where d2 < d1, and a modified groove having a second cross-sectional shape different from the first cross-sectional shape, The method according to claim 1, including the method described in claim 1.

4. The method according to claim 1, step i) is performed by using a laser source to generate a laser beam directed toward the workpiece along an optical path, wherein a beam shaper is positioned in the optical path to create an irradiation pattern on the workpiece.

5. The method according to claim 1, wherein the workpiece has a thickness in the range of 100 μm to 350 μm, the groove has a depth in the range of 5 μm to 60 μm, optionally the workpiece has a thickness in the range of 100 μm to 200 μm, the groove has a depth in the range of 5 μm to 15 μm, optionally the workpiece has a thickness in the range of 200 μm to 350 μm, and the groove has a depth in the range of 40 μm to 60 μm.

6. The method according to claim 2, wherein the incident laser light has a wavelength in the range of 300 nm to 380 nm, and optionally in the range of 330 nm to 350 nm.

7. The method according to claim 2, wherein the incident laser light comprises a pulsed beam having a frequency in the range of 10 kHz to 100 kHz and a pulse duration in the range of 10 ns to 250 ns.

8. The method according to claim 2, wherein the incident laser light comprises a pulsed beam having a frequency in the range of 100 kHz to 2000 kHz and a pulse duration in the range of 0.1 ps to 10 ps.

9. The method according to claim 2, wherein the incident laser light has an output in the range of 0.1 W to 10 W.

10. The method according to claim 1, wherein step ii) includes the step of applying a protective film to the second main surface and then applying the workpiece breaking force to the first main surface.

11. The method according to claim 1, step ii) includes placing the workpiece on a support with the first main surface facing upward and then applying a workpiece breaking force to the first main surface, and step iii) includes inverting the workpiece with the second main surface facing upward and applying the metal breaking force to the second main surface.

12. The method according to claim 1, wherein the workpiece contains silicon carbide.

13. A method for scribing a substantially planar workpiece, i) A step of irradiating the workpiece with a first irradiation pattern of incident laser light while moving the workpiece in a translational direction relative to the incident laser light to form a groove in the workpiece that extends parallel to a plane, wherein the groove opens on the upper surface of the workpiece and has a first cross-sectional shape with a first depth d1, and subsequently ii) While irradiating the workpiece with a second irradiation pattern of incident laser light, move the workpiece relative to the incident laser light in a direction parallel to the translation direction to modify the upper part of the groove, the upper part having a depth d2 where d2 < d1, and a modified groove having a second cross-sectional shape different from the first cross-sectional shape, Methods that include...

14. The method according to claim 13, wherein each of steps i) and ii) is performed by using a laser source to generate a laser beam directed toward the workpiece along an optical path, and a beam shaper is positioned in the optical path to create the respective first or second irradiation pattern on the workpiece.

15. The method according to claim 13, further comprising step ii) removing heat-affected material of the workpiece adjacent to the upper part of the groove.

16. The method according to claim 14, wherein the first irradiation pattern includes a linear arrangement of spatially separated laser subbeams separated from each of the laser beams.

17. The method according to claim 14, wherein the second irradiation pattern includes a plurality of sub-beams arranged in a V-shape, perpendicular to the translational direction, such that the width of the pattern increases in the translational direction.

18. The method according to claim 13, wherein the second irradiation pattern includes a plurality of pairs of sub-beams spaced apart parallel to the translational direction, each pair including first and second sub-beams spaced apart horizontally perpendicular to the translational direction, and the spacing between the first and second sub-beams of each pair increases in the translational direction.

19. The method according to claim 13, wherein the substantially planar workpiece comprises silicon carbide.

20. A method for dicing a substantially planar workpiece, comprising the step of scribing the workpiece using the method of claim 13 to create at least one modified groove in the workpiece, iii) Mechanically breaking the scribing workpiece along the at least one modified groove. The method that follows.

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