TW202019601A - Incident radiation induced subsurface damage for controlled crack propagation in material cleavage - Google Patents

Abstract

A cleaving system employs a shaper, a positioner, an internal preparation system, an external preparation system, a cleaver, and a cropper to cleave a workpiece into cleaved pieces. The shaper shapes a workpiece into a defined geometric shape. The positioner then positions the workpiece such that the internal preparation system can generate a separation layer at the cleaving plane. The internal preparation system focuses a laser beam internal to the workpiece at a focal point and scans the focal point across the cleaving plane to create the separation layer. The external preparation system scores the external surface of the workpiece at a location coplanar to the separation layer. The cleaver cleaves the workpiece by propagating the crack on the external surface along the separation layer. The cropper shapes the cleaved piece into a geometric shape as needed.

Description

Subsurface damage caused by incident radiation used for controlled crack propagation in material cracking

The present invention relates generally to material handling and more specifically to the use of incident radiation to prepare workpieces for cracking and for cracking workpieces.

Semiconductors are one of the important and valuable materials in the electronics and photovoltaic industry due to their unique properties, multi-purpose applications, and now widely used. Semiconductors are usually used in wafer form. However, current wafer fabrication methods are wasteful and can cause up to 50% material loss. It is an industry standard to saw a large semiconductor ingot/block mechanical wire into a thin wafer form, but the loss of incision caused by the saw wire is inevitable. Sawing also damages the surface of the resulting wafer, resulting in the need for damaged material removal and subsequent surface processing to achieve the advanced wafers required for many applications. Polishing and mechanical grinding are commonly used to process the surface of the wafer, and these post-processing steps remove even more material from the wafer, thereby further increasing the overall material loss. The high material loss during manufacturing of semiconductor wafers results in fewer semiconductor materials available for applications and higher cost per wafer. A similar argument can be made for advanced insulators used in a wide range of industries for diverse applications (for example, such as silicon oxide, aluminum oxide, zirconium oxide, magnesium oxide, etc.).

Expansion of cracked material workpieces through cracks is one of the promising alternatives to current wafer processing methods because it results in very little material loss. In addition, it is seen that this type of cracking results in a higher quality wafer surface, which may reduce or eliminate the need for post-processing steps to achieve a high quality surface finish. However, it is challenging to efficiently produce wafer systems through these cracking methods.

The present invention describes a cracking system that uses a reduced amount of force to accurately crack a workpiece into one or more cracking pieces compared to conventional techniques. The cracking system includes a shaper, a positioner, an internal preparation system, an external preparation system, a cracker and a truncator.

The cracking system can use various methods to produce cracking parts. For example, the shaper shapes a workpiece into a defined geometry (such as a cylinder). In this way, any one of the cracking pieces produced by the cracking system can be a cross-section (eg, a circle) of the defined geometry. The cracking system determines a position of a cracking plane inside the workpiece. Next, the positioner positions the workpiece so that the internal preparation system can create a separation layer at the cracking plane.

To create the separation layer, the internal preparation system focuses a laser beam to a focal point inside the workpiece to produce a local area in the workpiece where the mechanical properties have changed ("coverage area"). The internal preparation system scans the laser beam across the cleavage plane to create the separation layer by creating many coverage areas. The separation layer is a layer of material within the workpiece that is structurally different from the material surrounding the separation layer. The structural difference between the separation layer and the surrounding materials facilitates the cracking of the workpiece into cracked parts. More than one separation layer can be produced inside the workpiece.

The external preparation system scores the external surface of the workpiece at a position coplanar with the separation layer. Next, the cracker cracks the workpiece by expanding cracks on the outer surface along the separation layer. More specifically, the cracking system exerts a pulling force on the opposite ends of the workpiece to expand the crack along different materials of the separation layer and thereby produce a cracking element. The truncator shapes the cracking member into any geometric shape as needed.

Cross-reference of related applications

This application claims the rights of US Provisional Application No. 62/703,642 filed on July 26, 2018, the entire contents of which are hereby incorporated by reference. System Overview

FIG. 1 illustrates a system environment 100 for cracking a workpiece 130 according to an embodiment. The environment 100 includes a system controller 120, a cracking system 110, and a workpiece 130. Within the environment 100, the system controller 120 determines a cleavage plane 160 for one of the workpieces 130. The system controller 120 controls the cracking system 110 to produce a separation layer 140 along the cracking plane 160 within the workpiece 130. To this end, the cracking system 110 creates a footprint 150 within the workpiece 130 to facilitate the cracking of the workpiece 130 by the cracking system 110. Next, the system controller 120 controls the cracking system 110 to crack the workpiece along the separation layer 140. Cracking system

FIG. 2 shows a cracking system 110 in the environment 100. The cracking system 110 splits a workpiece 130 into two or more pieces. When the workpiece 130 is a semiconductor ingot, the cracking system 110 can crack the semiconductor ingot into one or more semiconductor wafers.

The cracking system 110 includes a shaper 210, a positioner 220, an internal preparation system 230, an external preparation system 240, a cracker 250 and a truncator 260.

The shaper 210 shapes the workpiece 130 so that the workpiece 130 can be cracked by the cracking system 110. Shaping the workpiece 130 may include shaping the workpiece 130 into a known geometry, such as a cylinder, a rectangular prism, or some other shape. In some examples, shaping the workpiece 130 may include adding material or removing material from the workpiece 130. Removal of material from the workpiece 130 can be accomplished by a saw, a grinder, an etching procedure, or some other instrument or procedure that can remove material from the workpiece 130. Adding material to the workpiece 130 can be accomplished by chemical vapor deposition, thermal oxidation, atomic layer deposition, or any other method of adding material to the workpiece. In some cases, the shaped workpiece 130 may be received from an external source or supplier. In any case, the shaped workpiece 130 has a shape that can be cracked by the cracking system 110.

The shape of the workpiece 130 is selected based on the desired shape of the cracking part. Some examples include a workpiece 130 having a circular, rectangular, square, or pseudo-square cross-sectional area to produce pieces having the same shape. In other examples, the shape of the workpiece 130 is not the shape of the resulting piece. To form commercially viable parts (eg, wafers), compliance with industry standards may be preferred. For example, a 4-inch round wafer is a standardized, commonly used type of wafer, so the workpiece 130 used to form the wafers will have a cross-sectional area of a circle with a diameter of 4 inches (or 100 mm) Cylindrical. Other standard diameters for round wafers include 1 inch (25 mm), 2 inch (51 mm), 3 inch (76 mm), 5.9 inch (150 mm), 7.9 inch (200 mm), and 11.8 inch (300 mm) And 17.7 inches (450 mm). The standard side lengths of quasi-square wafers include 125 mm and 156 mm, which are made by initial cylindrical pieces with diameters of 165 mm and 210 mm, respectively. In addition, according to industry standards, the workpiece 130 may include a notch or a flat portion. These characteristics can indicate the orientation of the crystal structure of the material (if it is monocrystalline). For example, an n-doped (100) silicon wafer has two flat portions parallel to each other, and may be made of a cylindrical workpiece 130 having two parallel flat portions cut on opposite sides of the length of the cylinder .

In addition, a truncator 260 can accurately truncate the cracking member to the desired geometry after the cracker 250 has cracked the workpiece 130. This allows the cracking system 110 to crack the workpiece 130 in a shape but produces a cracked piece of final geometry. For example, the cracker 250 is configured to crack the square workpiece 130. Thus, the shaper 210 shapes the workpiece 130 into a square shape and splits the workpiece 130 into square wafers. However, in this case, the desired shape of the wafer is a circle. Therefore, the truncator 260 truncates the square wafer into a round wafer of the desired geometry. The interceptor 260 performs its function by any method of removing material from the wafer (including but not limited to laser cutting, wafer sawing, chemical etching, waterjet cutting, etc.).

In addition, the workpiece 130 may be shaped so that the two surfaces of the workpiece 130 are parallel to a cracking plane 160. The cracking plane 160 is the plane of the workpiece 130 (the cracker 250 cracks along this plane) that is predefined by the separation layer 140 and determined by the system controller 120. The two surfaces may be parallel to the cracking plane 160 so that the cracker 250 can crack the workpiece 130 more efficiently. An example of this procedure is described in more detail with respect to FIGS. 7A to 8C. Generally speaking, the two surfaces or faces are on opposite ends of the workpiece 130. For example, for a workpiece 130 that is a cylindrical, single crystal silicon ingot (where the long axis of the ingot is perpendicular to the (100) crystal plane), the shaper 210 can shape the workpiece 130 so that it has opposite ends on the ingot Two planes with the same (100) crystal orientation.

The outer surface of the shaped workpiece 130 may include residual surface roughness. Therefore, in some configurations, the shaper 210 prepares the surface of the workpiece 130 for cracking by reducing the surface roughness. In various embodiments, the shaper 210 uses a mechanical polishing, a chemical mechanical polishing, a wet etching process (eg, a chemical etching process), a dry etching process (eg, reactive ion etching), and a hot surface reflow The procedure or any other procedure that can prepare the surface of the workpiece 130 for cracking to prepare the surface.

The positioner 220 positions the workpiece 130 and/or the cracking system 110 during the cracking process. In one example, the positioner 220 positions the workpiece 130 while the cracking system 110 remains stationary. Alternatively, the positioner 220 positions the cracking system 110 while the workpiece 130 remains stationary. In some cases, the positioner 220 positions both the cracking system 110 and the workpiece 130 simultaneously. More generally, the positioner 220 facilitates cracking of the workpiece 130 by properly aligning the cracking system 110 and the workpiece 130. The positioner 220 may be any number of elements capable of positioning the workpiece 130 or the cracking system 110. For example, the positioner 220 may include components such as motors, positioning platforms, piezoelectric devices, and mounting accessories, together with appropriate sensing elements for detecting the position of the workpiece 130 and the cracking system 110, as well as accurately positioning the workpiece 130 and the cracking system 110 In order to carry out the subsequent processing control system.

The internal preparation system 230 prepares the workpiece 130 for cracking by creating a separation layer 140. A separation layer 140 is a layer of material in the workpiece 130 that is different from the surrounding materials and facilitates cracking along the plane of the separation layer 140. Generally speaking, the separation layer 140 is coplanar with the cleavage plane 160. To create the separation layer 140, the internal preparation system 230 generates a laser beam and focuses the laser beam at a focal point (ie, a coverage area 150) inside the workpiece 130. In other configurations, the internal preparation system can generate any other type of incident radiation that can generate a coverage area 150 within a workpiece 130. In general, the laser changes the structure of the workpiece 130 at the coverage area 150 to locally weaken the material, thereby creating a preferred location for crack propagation. The structure of the workpiece 130 is not substantially modified at any place except the coverage area 150. As an example, the internal preparation system 230 may generate a certain amount of thermal energy at the footprint 150 that melts the material of the workpiece 130 in that area.

The internal preparation system 230 cooperates with the positioner 220 to create a coverage area 150 along the cracking plane 160 within the workpiece 130. Thus, the footprint 150 generally changes the structure of the workpiece 130 in the cleavage plane 160 to create a separation layer 140. Because the structure of the workpiece 130 in the separation layer 140 is different from the structure around the separation layer 140, the workpiece 130 is more likely to crack along the plane of the separation layer 140. The procedure for generating a separation layer 140 is described in more detail with respect to FIG.

FIG. 3 shows the internal preparation system 230 in more detail. The internal preparation system 230 includes a laser source 310, a beam shaper 320, a coverage area positioning element 330, and a workpiece geometry compensation optics 340.

The laser source 310 generates pulses of radiation at a repetition rate. The laser pulse forms a collimated symmetric laser beam. The laser beam has a wavelength longer than the electronic band gap of the material of the workpiece 130, so that when the laser enters the workpiece 130, the material of the workpiece 130 is not excited by electrons. In general, the laser source 310 has a wavelength between, for example, 0.2 µm and 20 µm. This allows the internal preparation system 230 to create a separation layer 140 for the workpiece 130 having an electronic band gap between, for example, 0.1 eV and 10 eV.

In one embodiment, a beam shaper 320 generates an asymmetric laser beam. The optics of the beam shaper 320 are operable as a cylindrical telescope that produces an asymmetric laser beam. The asymmetric laser beam allows a larger coverage area 150 when focused in the workpiece 130. Generating a larger coverage area 150 from a single pulse allows the separation layer 140 to be made faster for the same laser repetition rate. The asymmetric light beam can also produce a thin separation layer 140. The thinner separation layer 140 allows the cracker 250 to use a lower force to crack a workpiece 130 and provide a smaller roughness on the resulting separation surface. In one embodiment, the main axis of the asymmetric laser beam is parallel to the long axis of the workpiece 130. In another embodiment, the main axis of the laser beam is perpendicular to the long axis of the workpiece 130. The laser beam can be re-collimated after the beam shaper 320. For some workpiece shapes, an asymmetric laser beam may not be necessary.

A coverage area positioning element 330 focuses the laser beam onto a coverage area 150 inside the workpiece 130. Generally speaking, the geometry of the coverage area 150 in the cleavage plane 160 is configurable, and the thickness of the coverage area 150 that determines the thickness of the separation layer 140 is less than, for example, 20 μm but can be any other size. In one embodiment, the coverage area positioning element 330 is a rotationally symmetric, positive focal length optic. The coverage area positioning element 330 can move along the propagation axis of the laser beam. The movement of the footprint positioning element 330 along this axis allows the depth of the footprint 150 in the workpiece 130 to vary along the same axis.

In an embodiment, the workpiece 130 and the workpiece geometry compensation optics 340 can move uniformly relative to the coverage area positioning element 330 to also change the depth of the coverage area 150 in the workpiece 130. In some cases, the depth of the coverage area 150 within the workpiece 130 may far exceed, for example, 1 mm. The depth of the coverage area 150 within the workpiece 130 is only limited by the optical transmission of the material of the workpiece 130 and the laser parameters (such as average power, peak power, and wavelength). The material properties of the workpiece 130 affect the laser parameters (ie, wavelength, peak power, average power) that can produce a coverage area 150 in the workpiece 130. For example, a laser with a first wavelength can be used to create a coverage area in a workpiece of a first material, and a laser with a second wavelength can be used to generate a coverage in a workpiece of a second material Similar coverage area. Other examples are also possible.

A workpiece geometry compensation optics 340 compensates for the shape of the surface of the workpiece 130 and reduces the effects of aberrations (such as astigmatism) to change the position of the coverage area positioning element 330 and maintain the flux required to produce a coverage area 150 in the workpiece 130 . Workpiece geometry compensation optics 340 may contain more than one element that compensates for a single aberration or many aberrations. For some workpiece shapes, this optic may not be necessary.

In summary, the internal preparation system 230 and the positioner 220 are configured to create a coverage area 150 at any location within the workpiece 130. In addition, the configuration of the internal preparation system 230 controls the shape and size of the coverage area 150. For example, one configuration of the internal preparation system 230 produces a coverage area 150 in the separation layer 140 that is a 4-μm×20-μm ellipse, while the other configuration produces a 20-μm diameter circle in the separation layer 140 One of the coverage area 150. As previously discussed, the thickness of the coverage area 150 will mainly be determined by the configuration of the beam shaper 320 and the coverage area positioning element 330, but will generally be less than 20 μm.

The internal preparation system 230 may have several other optical device combinations that function similarly. For example, refractive optical elements can be replaced by reflective optics (curved mirrors). The beam shaper 320 may be a deformed pair, rather than a cylindrical telescope. Workpiece geometry compensation optics 340 can be replaced by a free-form optic that will help compensate for any aberrations caused by previous optics in addition to the shape of workpiece 130.

The external preparation system 240 prepares the workpiece 130 for lysis by scoring the outer surface of the workpiece 130. The outer surface of the workpiece 130 is scored to introduce a crack into the workpiece 130. The cracker 250 expands the crack along the separation layer 140 throughout the workpiece 130 to crack the workpiece 130 into multiple pieces. In general, the external preparation system 240 scores the workpiece 130 at the same location as the separation layer 140 (desirably along the crack), but may scribble the workpiece 130 in other locations as needed. In one embodiment, the functions of the external preparation system 240 are performed by some or all components of the internal preparation system 230.

The external preparation system 240 can score the workpiece 130 in several ways. For example, the external preparation system 240 can ablate the material of the workpiece 130 with a laser, physically remove the material of the workpiece 130 (using a mechanical scribing, sawing, chiseling, etc.), and etch the workpiece 130 (using a gas , Chemicals, plasma, etc.) or any other procedure that can scribe the workpiece 130 to scribe the workpiece 130.

In an example in which the external preparation system 240 scores the workpiece 130 at the same position as the separation layer 140, scoring the surface may cause a crack to partially expand at the periphery of the separation layer 140. The partially expanded crack further spreads throughout the separation layer 140 when the workpiece 130 is cracked. For example, the internal preparation system 230 creates a separation layer 140 on one (100) plane of the silicon workpiece 130. The external preparation system 240 scores the silicon workpiece 130 along the periphery of the separation layer 140 and introduces a crack in the (100) plane. Therefore, when the cracker 250 cracks the silicon workpiece 130, the cracks extend along the (100) plane throughout the separation layer 140. The extent to which cracks extend along the separation layer 140 depends on the characteristics of the separation layer 140 (eg, thickness, uniformity, etc.), the method of scoring the workpiece 130 (eg, ablation, physical removal, etc.) and the material of the workpiece 130 And orientation (eg, crystal orientation, composition, etc.).

The cracker 250 splits the workpiece 130 into one or more pieces. In one example, the cracker 250 applies a mechanical pull 440 normal to one of the separation layers 140 to crack the workpiece 130. In one embodiment, the mechanical pulling force 440 is applied to the workpiece 130 through an electrostatic clamp 410 attached to the opposite end of the workpiece 130. A voltage 416 between the electrostatic clamp 410 and the workpiece 130 is applied so that they are firmly attached together. When a mechanical pulling force 440 is applied to pull the electrostatic clamp 410 apart in a controlled manner, the workpiece 130 is cracked.

FIG. 4 illustrates an exemplary procedure for cracking a workpiece 130 using a cracker 250 (eg, a capacitive clamp 410). A capacitive clamp 410 includes a non-conductive layer 414 and a conductive body 412. The non-conductive layer 414 is close to one surface of the conductive body 412. In some embodiments, the non-conductive layer 414 is deposited directly onto the face of the conductive body 412 so that it is chemically adhered. In many embodiments, the other side of the conductive body 412 is fixed to some kind of support 430. This can be done by any suitable means for mechanically or chemically fastening or attaching the two materials. If the support 430 is made of metal or another conductive material, a non-conductive attachment method is used to prevent the voltage 416 applied to the conductive body 412 from being applied to the support 430 and may cause a short circuit or some other hazards. In one embodiment, the workpiece 130 may be attached to the clamp 420 using epoxy or other types of adhesives, and the clamp 420 will remain permanent when the clamp 410 cracks multiple pieces from the workpiece 130 in a repeated manner贴贴至WORK130. In some embodiments, the shape of the capacitive clamp 410 matches the cross-sectional geometry of the workpiece 130.

The capacitive clamp 410 fixes the workpiece 130 by generating an electrostatic force such as that experienced by a plate of a parallel plate capacitor. A voltage supply 416 is used to energize the conductive body 412 to a high voltage, and the workpiece 130 is energized to the opposite polarity or to ground. In addition, the non-conductive layer 414 prevents any charge from being transferred from the conductive body 412 to the workpiece 130, and vice versa. Therefore, charges are accumulated at the closest surface of both the conductive body 412 and the workpiece 130. Because these charges are opposite and therefore attractive, an electric field is generated within the non-conductive layer 414 and an associated electrostatic force is also generated.

Although the workpiece 130 is fixed to the capacitive clamp 410 of the power required for the static strength may vary, but the compressive stress is applied is usually about 10 ⁶ Pa to 10 ⁸ Pa. This stress is usually generated by applying a voltage 416 from (including but not limited to) a range of 100 V to 500 kV (which depends on the thickness and dielectric properties of the non-conductive layer 414). For example, a 100-nm ₂ across the non-conductive layer thick HfO 414 100-V bias voltage is applied to produce about one-one 10 ⁸ Pa compressive stress. Similarly, applying a 500-kV bias across a 500-µm thick quartz non-conductive layer 414 will produce a compressive stress of approximately 10 ⁷ Pa. Fracture mechanics analysis indicates that the stress required to propagate the crack 404 depends mainly on the initial crack depth and the sharpness of the crack tip. For example, if the crack 404 partially spreads along the separation layer 140 generated by the internal preparation system 230, the amount of force required to crack the workpiece 130 will decrease. The flexibility of the depth of the initial crack 404 results in the electrostatic force required for expansion and therefore the flexibility of the voltage 416 required.

The surface finish of the capacitive clamp 410 can affect the strength and uniformity of the electrostatic force between the capacitive clamp 410 and the workpiece 130. Because air has a lower dielectric constant than the material used for the non-conductive layer 414, the air gap between the workpiece 130 and the non-conductive layer 414 can reduce the electric field existing between the workpiece 130 and the conductive body 412 and thus reduce Small electrostatic force. In addition, the random placement of the air gap can affect the uniformity of the electric field between the conductive body 412 and the workpiece 130, resulting in a less uniform electrostatic force. To reduce these effects, the contact surface of the non-conductive layer 414 may be as atomically flat as possible (eg, using a method such as polishing) to reduce the presence of air between the capacitive clamp 410 and the workpiece 130. If the material used for the non-conductive layer 414 is harder than the workpiece 130, polishing can also be used to prevent damage to the workpiece 130. In some embodiments, the surface finish depends on the materials used for conductive body 412 and non-conductive layer 414. In some embodiments, the conductive body 412 is made of a semi-conductive material.

The material used for the non-conductive layer 414 can affect the operation of the capacitive clamp 410 due to the amount of electrostatic force required to crack the workpiece 130. For a capacitive clamp 410 to function as a capacitor, the non-conductive layer 414 must be a dielectric material. The magnitude of the electric field where these materials decompose or lose their insulating properties is called dielectric strength. Since the electric field experienced by the non-conductive layer 414 is proportional to the electrostatic force generated by the capacitive clamp, it is advantageous to use a material with a high dielectric strength. Materials that have been found to withstand the necessary electric field size are diamond, cubic boron nitride, aluminum nitride, hafnium oxide, silicon oxide, silicon nitride, niobium oxide, barium titanate, strontium titanate, lithium niobate, aluminum oxide, Calcium fluoride, silicon carbide and any combination of these. However, this list is not restrictive, as other materials with similar high dielectric strength can also be used for this purpose. Once the dielectric material is considered, the dielectric constant is considered. Higher dielectric constant values result in lower voltages and therefore electric fields that need to be applied to achieve the same magnitude of electrostatic force. Therefore, the ideal material for the non-conductive layer 414 is a material having both high dielectric strength and high dielectric constant.

In some embodiments, the dielectric material used for the non-conductive layer 414 is coated with a thin layer of a different material. If the dielectric material is too hard and causes damage to the workpiece 130 during clamping, the thin layer coating may be one of the softer dielectric materials that does not damage the workpiece 130. If the dielectric is too soft and suffers damage during the clamp, the thin layer coating may be a harder dielectric material that better withstands the forces associated with the clamp. Artifact

Although this system is particularly suitable for semiconductor manufacturing, the workpiece 130 may be made of materials other than half of the conductive material. In various embodiments, the workpiece 130 should be conductive or semi-conductive so that charge can flow to the surface of the workpiece 130 that is mated with the capacitive clamp 410 when a voltage 416 is applied between the workpiece 130 and the conductive body 412 . Examples of workpiece 130 materials that meet these requirements include many semiconductors, such as silicon, silicon carbide, indium phosphide, gallium phosphide, germanium, gallium arsenide, and gallium nitride. If the material used for the workpiece 130 is not sufficiently conductive to meet these requirements, a small electrostatic force will be generated, and the capacitive clamp 410 may not be able to secure the workpiece 130 as strongly as required by the cracking process. However, these properties can still be achieved with a workpiece 130 made of an insulating material such as silicon oxide, aluminum oxide, zirconium oxide, and magnesium oxide. For example, in one embodiment, the shaper 210 may apply a thin conductive coating that is strongly bonded to the surface of the insulating material. To be considered as a strong bond, the thin conductive coating must be able to remain bonded to the surface of the insulating material during the application of the electrostatic and tensile forces used in the cracking procedure.

Positioning the separation layer 140 in the workpiece 130 can determine the crystal orientation of the resulting wafer. In many embodiments, the separation layer 140 is aligned with a specific crystal plane within the workpiece 130. Therefore, the crystal orientation of the resulting wafer is the same as the selected crystal plane. The standard crystal orientation of crystalline silicon includes (100), (111) and (110). System controller

In various embodiments, the system controller 120 controls various components of the cracking system 110 to crack the workpiece 130.

The system controller 120 determines a shape of the workpiece 130 based on the desired shape of the cracking part. For example, if the desired shape of the cracking member is circular, the controller 120 controls the shaper 210 to shape the workpiece 130 into a cylindrical shape. In one embodiment, the system controller 120 additionally controls an optional truncator 260 subsystem to truncate a cracking member to a final desired geometry. Generally speaking, controlling the shaper 210 includes: generating electrical signals to control various elements of the shaper 210 that can shape the workpiece 130. Similarly, the control truncator 260 includes various components that generate electrical signals to control the truncator 260 that can truncate the cracking member into a specified, final geometry.

The system controller 120 determines the positions of the workpiece 130, the external preparation system 240, and the internal preparation system 230 when the workpiece 130 is ready to be cracked and is cracked. Determining the location may include determining the spatial location of the workpiece 130 or the components of the cracking system 110 so that the cracking plane 160 of the workpiece 130 is irradiated by the internal preparation system 230. Once the position is determined, the system controller 120 can generate a control signal for the positioner 220 to locate the workpiece 130 or the components of the cracking system 110. Similarly, the system controller 120 may generate a control signal to cause the positioner 220 to position any other element or workpiece 130 of the cracking system 110.

The system controller 120 determines and adjusts the operating characteristics of the internal preparation system 230. In one example, the system controller 120 determines and adjusts the characteristics of the laser beam emitted by the laser source 310. The one or more laser beam characteristics may be determined based on, for example, the characteristics of the workpiece 130, the position of the separation layer 140, and the like. The characteristics of the laser source 310 and the laser beam may include wavelength, power, pulse rate, and so on. In addition, the system controller 120 can determine and adjust the appropriate positions of various optical elements to generate a coverage area 150 and a separation layer 140 inside the workpiece 130. The optical element can be further configured to control the size, shape, and position of the coverage area 150.

The system controller 120 determines and adjusts the operating characteristics of the external preparation system 240. In one example, when scoring the exterior of the workpiece 130, the system controller 120 determines and adjusts the positions of the workpiece 130 and the external preparation system 240. The system controller 120 can also determine and adjust the depth, width, and overall shape of the introduced crack.

The system controller 120 controls the operation of the cracker 250. That is, the system controller generates the voltage and signal required to cause the cracker 250 to crack the workpiece 130. In one embodiment, the system controller 120 controls a cracker 250 based on the capacitive clamp design shown in FIG. 4. Cracking procedure

FIG. 5 is a flow chart of a process 500 for cracking a workpiece 130 using a cracking system 110.

The system controller 120 determines a shape of the workpiece 130 based on the desired shape of the cracking part. Based on the determined shape, the shaper 210 shapes 510 the workpiece 130 into a desired shape. For example, if the shaped workpiece 130 will be square, the shaper 210 shapes 510 the workpiece 130 into a square prism with the necessary geometric specifications and tolerances required to successfully complete the rest of the cracking process.

The system controller 120 determines a position of a cleavage plane 160 in the workpiece 130. The internal preparation system 230 prepares 520 the workpiece 130 internally by creating a separation layer 140 at the desired cleavage plane 160 within the workpiece 130. In some cases, the internal preparation system 230 creates multiple separation layers 140 within the workpiece 130. These procedures are described in more detail with respect to FIG.

The system controller 120 determines a position to introduce a crack to the workpiece 130. The external preparation system 240 prepares 530 the workpiece 130 externally by creating a crack 404 on an outer surface that will spread along the separation layer 140 throughout the workpiece 130 when the workpiece 130 is cracked. In general, the crack 404 is along the periphery or a portion of the periphery of the separation layer 140 prepared by the internal preparation system 230. In some cases, the external preparation system 240 introduces several cracks 404 along the outer surface of the workpiece 130.

The system controller 120 generates a signal that causes the cracker 250 to crack 540 the workpiece 130. In one embodiment, the cracked workpiece 130 spreads the crack 404 along the separation layer 140 by generating a mechanical pulling force 440 on the opposite end of the workpiece 130. That is, the workpiece 130 is cracked by pulling the workpiece 130 into two pieces at the separation layer 140. In general, the cracked workpiece 130 is such that the cracked surface is orthogonal to the long axis of the workpiece 130. In another embodiment, the cracked workpiece 130 generates a stress inside the workpiece 130 by applying a controlled shear force to the workpiece so that the crack 404 preferentially expands along the separation layer 140 to cause the crack 404 to expand. In yet another embodiment, the cracked workpiece 130 generates cracks within the workpiece 130 by generating a general mechanical stress composed of a variable combination of compressive stress, tensile stress, shear stress, bending stress, torsional stress, or fatigue stress. 404 preferentially expands along the separation layer 140 to expand the crack 404. In yet another embodiment, cracking 540 the workpiece 130 spreads the crack 404 along the separation layer 140 by applying a thermal stress that can be achieved by rapidly heating or cooling the workpiece 130. In yet another embodiment, cracking 540 the workpiece 130 by applying a powerful vibration that can be achieved by a piezoelectric actuator, magnetostrictive actuator, or similar device that generates a strong acoustic wave in the workpiece 130 causes the crack 404 to follow The separation layer 140 is expanded. In yet another embodiment, cracking 540 the workpiece 130 can be achieved by any combination of the above methods.

The system can crack 540 workpieces 130 any number of times. In various embodiments, this may include preparing 520 the workpiece 130 internally, preparing 530 the workpiece externally, and cracking 540 the workpiece 130 any number of times. These steps may occur in different arrangements based on the configuration of the cracking system 110 and repeat any number of times. Internal preparation

FIG. 6 is a flowchart of a procedure 600 for internally preparing a workpiece 130 using an internal preparation system 230.

Here, the system controller 120 has decided to use one of the cleavage planes 160 of the workpiece 130. Therefore, the system controller 120 configures 610 the internal preparation system 230 to produce a separation layer 140 at the desired cleavage plane 160 within the workpiece 130. Configuring the internal preparation system 230 may include positioning optics, positioning the workpiece 130, configuring laser source 310 parameters, etc., so that the internal preparation system 230 generates an appropriate coverage area 150 within the workpiece 130.

Next, the system controller 120 controls the laser source 310 to project 620 a laser beam toward the workpiece 130. The laser beam is focused into the workpiece 130 by various optical devices of the internal preparation system 230. The laser beam generates 630 inside the workpiece 130 along the desired split plane 160 a coverage area 150 that changes the structure of the workpiece 130 in that area.

7A and 7B show an example of preparing a workpiece 130 for cracking by generating 630 a coverage area 150 inside. 7A is an isometric view of one of the workpieces 130 during internal preparation, and FIG. 7B is a cross-sectional view of one of the workpieces 130 during internal preparation.

In this example, because the cracking member will be circular, the workpiece 130 is a cylindrical ingot. The cracking plane 160 is orthogonal to the long axis of the workpiece 130. The laser beam 710 is incident on the surface of the workpiece 130 and is focused on a coverage area 150. The footprint 150 is coplanar with the cracking plane 160.

Returning to FIG. 6, the system controller 120 configures 610 the internal preparation system 230 again. In this example, the internal preparation system 230 is configured to reposition the optics so that the coverage area 150 inside the workpiece 130 is at a different location on the cleavage plane 160. After configuring the internal preparation system 230 again, the system controller 120 projects 620 a beam of light that is focused to produce 630 a new coverage area 150. This procedure is shown in Figures 7C and 7D.

In particular, FIGS. 7A to 7D illustrate an example in which the main axis of the laser beam used to prepare a workpiece 130 is perpendicular to the long axis of the workpiece 130, but other examples of laser beam orientation are also feasible. For example, the laser beam can be perpendicular to the long axis of the workpiece. In this case, the laser beam will enter the workpiece from the top surface of the workpiece instead of one of the side surfaces of the workpiece.

The process of generating the coverage area 150 continues iteratively until the coverage area 150 generally produces a separation layer 140. FIG. 8A shows an example of a coverage area 150 where a separation layer 140 is formed on a cleavage plane 160 of a workpiece 130. The crack plane 160 is the plane of the page. In other embodiments, the separation layer 140 may have various coverage area 150 densities. That is, in some examples, the coverage area 150 may have some overlap or may have additional spacing between the coverage areas 150. In addition, the system controller 120 can generate the separation layer 140 using a specific coverage area 150 pattern. For example, the system controller 120 may use a raster pattern from one side to the other side, a pattern that starts at the center and spirals outward, a pattern that forms a concentric ring of the coverage area 150, and the like to generate the coverage area 150. Regardless of the pattern and density, a separation layer 140 is generated in the coverage area 150. 8B and 8C show an isometric representation and a cross-sectional representation of the separation layer 140.

Returning to FIG. 6, the system controller 120 determines the position of another separation layer 140. Thus, the system controller 120 causes the positioner 220 to reposition the workpiece 130 and/or the internal preparation system 230 to create another separation layer 140. Generally speaking, the positioner 220 positions 640 the workpiece 130 by moving the workpiece 130 along its long axis to create another separation layer 140 parallel to the first separation layer 140. Once the workpiece 130 and the internal preparation system 230 are properly positioned, the internal preparation system 230 generates another separation layer 140. FIG. 9 shows an example of a workpiece 130 after generating a plurality of separation layers 140. The distance between the separation layers 140 specifies the thickness of the cracked pieces produced after cracking. The distance between the separation layers may be limited by the thickness of a separation layer 140. For example, the separation layer may have a minimum thickness t ' , and the distance between two adjacent separation layers in the workpiece is greater than, for example, t '/2 . In general, the thickness of the resulting wafer is greater than 10 µm but can be less than 10 µm. In another embodiment, the plurality of separation layers 140 are made in parallel in such a way that the previous coverage area 150 does not cause interference when the new coverage area 150 is generated.

FIG. 10A shows an example of a workpiece 130 that has been cracked along a separation layer 140. The workpiece 130 is split into a top part 1010 and a bottom part 1030 along the separation layer 140 (in this example, it is coplanar with the cracking plane 160). Here, the bottom surface 1020 of the top member 1010 is at the separation layer 140, and similarly, the top surface 1040 of the bottom member 1030 is at the separation layer 140.

FIG. 10B shows an example of a workpiece 130 that has been cracked along several separation layers 140. In this example, the workpiece is split into a top part 1050, an intermediate piece 1060, and a bottom part 1070. The previously joined surface is the location of the cleavage plane 160 and the coplanar separation layer 140. In various embodiments, the cracking system 110 may crack the workpiece 130 into any number of pieces. Each piece may have any desired thickness based on the proximity of the separation layer 140 and the cleavage plane 160.

The previous descriptions of embodiments of the invention have been presented for purposes of illustration; they are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Those skilled in the relevant art can understand that many modifications and changes are feasible in view of the above disclosure.

Finally, the language used in this specification has been selected primarily for readability and instructional purposes, and it may not be selected to depict or limit the subject matter of the present invention. Therefore, the scope of the present invention is not intended to be limited by this [embodiment], but by the scope of patent applications for any invention based on one of the applications discussed. Therefore, the disclosure of the embodiments of the present invention is intended to clarify rather than limit the scope of the present invention described in the following patent application scope.

100: system environment 110: Cracking system 120: System controller 130: Workpiece 140: Separation layer 150: coverage area 160: cracking plane 210: Former 220: locator 230: Internal preparation system 240: External preparation system 250: cracker 260: Truncator 310: Laser source 320: beam shaper 330: coverage area positioning element 340: Workpiece geometry compensation optics 404: Crack 410: Electrostatic clamp/capacitive clamp 412: conductive body 414: Non-conductive layer 416: voltage/voltage supply 420: clamp 440: Mechanical pull 500: program 510: Forming 520: Preparation 530: Preparation 540: Crack 600: program 610: Configuration 620: projection 630: Generate 640: positioning 710: Laser beam 1010: Top part 1020: bottom surface 1030: bottom part 1040: top surface 1050: top part 1060: Middleware 1070: bottom part

FIG. 1 illustrates a system for cracking a workpiece according to an example embodiment.

FIG. 2 illustrates a cracking system for cracking a workpiece according to an example embodiment.

FIG. 3 illustrates an internal preparation system according to an example embodiment.

FIG. 4 illustrates a cracker according to an example embodiment.

FIG. 5 is a program flow for cracking a workpiece according to an example embodiment.

6 is a program flow for generating a separation layer within a workpiece according to an example embodiment.

7A to 7D illustrate a separation layer generated inside a workpiece according to an example embodiment.

FIG. 8A illustrates a footprint that creates a separation layer in a workpiece according to an example embodiment.

8B and 8C illustrate a separation layer inside a workpiece according to an example embodiment.

9 illustrates a workpiece with multiple separation layers according to an example embodiment.

10A-10B illustrate an example of a work piece cracked along one or more separation layers 140. FIG.

The drawings depict various embodiments of the present invention for purposes of illustration only. Those skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein can be employed without departing from the principles of the invention described herein.

100: system environment

110: Cracking system

120: System controller

130: Workpiece

140: Separation layer

150: coverage area

160: cracking plane

Claims (21)

A method for cracking a work piece of a material, including: Using a pulsed laser generated by an internal preparation system to produce a separation layer in the workpiece with material properties different from the rest of the workpiece; Scoring the workpiece using an external preparation system to produce a crack on a surface of the workpiece that is coplanar with and overlaps the separation layer; A cracker is used to crack the workpiece to produce a cracking element by generating a pulling force on the workpiece that is substantially perpendicular to the separation layer to cause the crack to expand along the separation layer. The method of claim 1 further includes: A forming system is used to shape the workpiece into a defined geometry such that the cracking element has a perimeter as a cross section of the defined geometry. The method of claim 1 further includes: Using a controller to determine a position of a cleavage plane in the workpiece orthogonal to a first axis of the workpiece; and A positioner is used to position the workpiece so that the cleavage plane is coplanar with the separation layer. The method of claim 1, wherein generating the separation layer further comprises: Focusing the pulsed laser to a coverage area inside the workpiece, wherein the pulses of the pulsed laser locally change the material properties of the workpiece at the coverage area. The method of claim 1, wherein generating the separation layer further comprises: A focal point of the pulsed laser is moved within the workpiece to produce the separation layer, and the separation layer is formed as a focus of the focal point when the focal point moves within the workpiece. The method of claim 1, wherein cracking the workpiece further comprises: Attach the cracker to the opposite end of the workpiece; and The pulling force that causes the crack to expand along the separation layer is generated, and the pulling force is generated between the opposite ends of the workpiece and is perpendicular to the separation layer. The method of claim 6, wherein the cracker is electrostatically attached to the opposite end of the workpiece. The method of claim 1 further includes: A cleaver is used to truncate the cracking element to a specific geometry. The method of claim 1 further includes: The pulsed laser is used to create another separation layer with different material properties within the workpiece. The method of claim 8 further includes: The cracker is used to crack the workpiece along the other separation layer to produce another cracking piece. As in the method of claim 1, where: This material is a semiconductor, And the cracking element is a semiconductor wafer. A system for cracking a workpiece of a material, including: An internal preparation system configured to generate a pulsed laser beam for generating a separation layer within the workpiece, the separation layer having material properties different from the remaining materials of the workpiece; An external preparation system configured to scribe the workpiece to produce a crack on the surface of the workpiece coplanar with and overlapping the separation layer; and A cracker configured to generate a cracking part of the workpiece by generating a pulling force on the workpiece perpendicular to the separation layer to spread the crack along the separation layer. If the system of claim 12, it further includes: A shaper configured to shape the workpiece into a defined geometry before and/or after the generation of a separation layer, such that the cracking member has a perimeter as a cross-section of the defined geometry. If the system of claim 12, it further includes: A controller configured to determine a position of a plane to be cracked within a workpiece orthogonal to a first axis of the workpiece; and A positioner configured to position the workpiece before and when the separation layer is generated so that the desired cleavage plane will be coplanar with the separation layer. The system of claim 12, wherein the internal preparation system further includes: A focusing system configured to focus a pulsed laser to a coverage area inside the workpiece, wherein each focused laser pulse locally changes the material properties of the workpiece at the coverage area; and The same focusing system, which is configured to move the focal point of the pulsed laser within the workpiece to produce the separation layer through the generation of many coverage areas. The system of claim 12, wherein the internal preparation system further includes: A focusing system configured to move the focal point of the laser pulses within the workpiece to generate the separation layer through the generation of many coverage areas. If the system of claim 12, it further includes: The cracker, which is further configured to be attached to the opposite end of the workpiece, then generates the pulling force on the workpiece perpendicular to the separation layer to expand the crack along the separation layer. If the system of claim 12, it further includes: A truncator configured to truncate the cracking member into a specific geometry. The system of claim 12, wherein the internal preparation system is further configured to use the pulsed laser to create another separation layer with different material properties within the workpiece. The system of claim 19, wherein the cracker is further configured to crack the workpiece along the another separation layer to produce another cracking member. As in the system of claim 12, where: This material is a semiconductor, And the cracking element is a semiconductor wafer.

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