JP7174850B2 - Method and system for shearing a workpiece of material - Google Patents

Description

The present invention relates generally to material processing, and more particularly to preparing workpieces for shearing and shearing of workpieces using incident radiation.

Semiconductors are important and valuable materials in the electronics and photovoltaic industries because of their unique properties, many applications, and their current widespread use. Semiconductors are often used in wafer form.

However, current wafer fabrication methods are wasteful and can result in material loss of up to 50%. Mechanical wire sawing of large semiconductor ingots/blocks into thin wafers is an industry standard, but kerf loss from the saw wire is inevitable. Sawing also leaves damage on the surface of the resulting wafer, requiring removal of the damaged material and subsequent surface finishing to achieve the high quality wafers required for many applications. Polishing and mechanical grinding are often used to finish the surface of the wafer, but these post-processing steps remove even more material from the wafer, further increasing overall material loss. Greater material loss during the manufacture of semiconductor wafers results in less semiconductor material being available for the intended application and higher cost per wafer. Similar arguments can be applied to high quality insulators (eg, silicon oxide, aluminum oxide, zirconium oxide, magnesium oxide, etc.) used in a wide variety of industries for various applications.

Shearing of material workpieces by crack propagation is a promising alternative to current wafer processing methods because there is little material loss. Additionally, this type of shear has been found to result in a higher quality wafer surface, potentially reducing or eliminating the need for post-processing steps to achieve a high quality surface finish. However, it is very difficult to efficiently manufacture wafers by such shearing methods.

A shearing system is described for precisely shearing a workpiece into one or more sheared pieces with less force than conventional techniques. Shearing systems include shapers, positioners, internal preparation systems, external preparation systems, shears, and croppers.

A shear system may employ a variety of methods for generating shear pieces. For example, a shaper shapes a workpiece into a defined geometric shape, such as a cylinder. Any sheared piece produced by the shearing system in this manner may have a cross-section of a defined geometric shape (eg, circular). A shear system determines the location of the shear plane within the workpiece. A positioner then positions the workpiece such that an internal preparation system can create a separation layer at the shear plane.

To create the separation layer, the internal preparation system focuses a laser beam inside the workpiece at a focal point to create a localized area (footprint) within the workpiece with altered mechanical properties. An internal preparation system scans the laser beam across the shear plane and creates a number of footprints to create the separation layer. An isolation layer is a layer of material within the workpiece that is structurally different from the material surrounding the isolation layer. Structural differences between the separating layer and the surrounding material facilitate shearing the workpiece into shear pieces. Multiple separation layers may be created within the workpiece.

An external preparation system cuts the outer surface of the workpiece at locations coinciding with the separation layer. The shears then shear the workpiece by propagating cracks in its outer surface along the separating layer. More specifically, the shear system applies a tensile force to both ends of the workpiece, which causes cracks to propagate along the dissimilar materials of the separation layer, thereby creating shear fragments. The cropper shapes the sheared pieces into any geometric shape as needed.

1 illustrates a system for shearing a workpiece, according to one embodiment; 1 illustrates a shearing system for shearing a workpiece, according to one embodiment. 1 illustrates an internal provisioning system, according to one embodiment. 1 illustrates a shears, according to one embodiment. 1 is a process flow for shearing a workpiece, according to one embodiment; 4 is a process flow for creating a separation layer within a workpiece, according to one embodiment. 4 illustrates the creation of a separation layer inside a workpiece, according to one embodiment. 4 illustrates the creation of a separation layer inside a workpiece, according to one embodiment. 4 illustrates the creation of a separation layer inside a workpiece, according to one embodiment. 4 illustrates the creation of a separation layer inside a workpiece, according to one embodiment. 4 illustrates a footprint for creating a separation layer within a workpiece, according to one embodiment. 1 illustrates a separation layer inside a workpiece, according to one embodiment. 1 illustrates a separation layer inside a workpiece, according to one embodiment. 1 illustrates a workpiece having multiple separation layers, according to one embodiment. An example of a workpiece sheared along one or more separation layers 140 is shown. An example of a workpiece sheared along one or more separation layers 140 is shown.

These figures are for illustrative purposes only and depict various embodiments of the present invention. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods shown herein can be employed without departing from the inventive principles described herein. be.

System Overview FIG. 1 illustrates a system environment 100 for shearing a workpiece 130, according to one embodiment. Environment 100 includes system controller 120 , shear system 110 , and workpiece 130 . Within environment 100 , system controller 120 determines shear plane 160 of workpiece 130 . System controller 120 controls shear system 110 to create separation layer 140 within workpiece 130 along shear plane 160 . To that end, shearing system 110 creates footprint 150 within workpiece 130 , thereby facilitating operation of shearing system 110 to shear workpiece 130 . System controller 120 then controls shear system 110 to shear the workpiece along separation layer 140 .

Shear System FIG. 2 shows a shear system 110 within environment 100 . Shearing system 110 shears workpiece 130 into two or more pieces. If workpiece 130 is a semiconductor ingot, shear system 110 can shear the semiconductor ingot into one or more semiconductor wafers.

Shearing system 110 includes shaper 210 , positioner 220 , internal preparation system 230 , external preparation system 240 , shears 250 and cropper 260 .
Shaper 210 shapes workpiece 130 so that workpiece 130 can be sheared by shearing system 110 . Shaping the workpiece 130 may include forming the workpiece 130 into a known geometric shape, such as a cylindrical shape, a rectangular prism, or some other shape. In some examples, shaping the workpiece 130 may include either adding or removing material from the workpiece 130 . Removal of material from workpiece 130 may be accomplished by a saw, grinder, etching process, or any other instrument or process capable of removing material from 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 vendor. In any event, the formed workpiece 130 has a shape that can be sheared by the shearing system 110 .

The shape of the workpiece 130 is selected based on the desired shape of the shear piece. Some examples include workpieces 130 having circular, rectangular, square, or quasi-square cross-sectional areas to produce pieces of the same shape. In other examples, the shape of workpiece 130 is different than the shape of the generated pieces. In forming commercially viable pieces (eg, wafers), it may be preferable to adhere to industry standards. For example, a 4 inch (100 mm) circular wafer is a standardized and commonly used type of wafer, so the workpiece 130 used to form such a wafer may be 4 inch (100 mm) ) will be cylindrical with a cross-sectional area of a circle of diameter . Other standard diameters for circular wafers include 1 inch (25 millimeters), 2 inches (51 millimeters), 3 inches (76 millimeters), 5.9 inches (150 millimeters), and 7.9 inches (200 millimeters). , 11.8 inches (300 millimeters), and 17.7 inches (450 millimeters). Standard side lengths for quasi-square wafers include 125 millimeters and 156 millimeters and are produced from cylindrical pieces with diameters of 165 millimeters and 210 millimeters, respectively. Additionally, workpiece 130 may include notches or flats according to industry standards. These features can indicate the orientation of the crystal structure of the material if it is single crystal. For example, an n-doped (100) silicon wafer has two flats parallel to each other, resulting from a cylindrical workpiece 130 cut with two parallel flats on either side of the cylindrical length. can do.

Additionally, the cropper 260 can precisely cut the sheared pieces into a desired geometric shape after the shears 250 shear the workpiece 130 . This allows the shearing system 110 to shear a workpiece 130 in a shape to produce a sheared piece of final geometric shape. For example, shears 250 are configured to shear square workpieces 130 . Thus, the shaper 210 shapes the workpiece 130 into squares and shears the workpiece 130 into square wafers. However, in this case the desired shape of the wafer is circular. Thus, the cropper 260 cuts the square wafer into circular wafers of the desired geometric shape. Cropper 260 accomplishes its function through any method of removing material from a wafer, including but not limited to laser cutting, wafer sawing, chemical etching, water jet cutting, and the like.

Additionally, the workpiece 130 can be shaped such that two surfaces of the workpiece 130 are parallel to the shear plane 160 . Shear plane 160 is the plane of workpiece 130 , predefined by separation layer 140 and determined by system controller 120 , along which shears 250 shear. In various embodiments, the shear plane can be a topological plane other than a two-dimensional plane. The two surfaces can be parallel to the shear plane 160 so that the shears 250 can shear the workpiece 130 more efficiently. An example of this process is described in more detail in connection with FIGS. 7A-8C. Generally, these two surfaces or faces are at opposite ends of workpiece 130 . For example, for a workpiece 130 that is a cylindrical monocrystalline silicon ingot in which the long axis of the ingot is perpendicular to the (100) crystallographic plane, the shaper 210 will place the workpiece 130 into the same (100) crystallographic plane at both ends of the ingot. It can be molded to have two oriented faces.

The outer surface of the molded workpiece 130 may have residual surface roughness. Thus, in some configurations, shaper 210 prepares the surface of workpiece 130 for shearing by reducing the roughness of the surface. In various embodiments, the shaper 210 is subjected to mechanical polishing, chemical-mechanical polishing, wet etching processes (eg, chemical etching processes), dry etching processes (eg, reactive ion etching), thermal surface reflow processes, or shearing. Prepare the surface using any other process capable of preparing the surface of the workpiece 130 for the purpose.

Positioner 220 positions workpiece 130 and/or shear system 110 during the shearing process. In one example, positioner 220 positions workpiece 130 while shearing system 110 remains stationary. Alternatively, positioner 220 positions shear system 110 while workpiece 130 remains stationary. In some cases, positioner 220 positions both shear system 110 and workpiece 130 simultaneously. Most generally, positioner 220 facilitates shearing of workpiece 130 by properly aligning shear system 110 and workpiece 130 . Positioner 220 may be any number of elements capable of positioning workpiece 130 or shear system 110 . For example, positioner 220 includes motors, positioning stages, along with suitable sensing elements for detecting the positions of workpiece 130 and shear system 110, and the control systems necessary to accurately position them for subsequent processing. , piezoelectric elements, and mounting fixtures.

Internal preparation system 230 prepares workpiece 130 for shearing by creating separation layer 140 . Separation layer 140 is a layer of material within workpiece 130 that is different from the surrounding material that facilitates shearing along the plane of separation layer 140 . Generally, separation layer 140 is coplanar with shear plane 160 or has the same orientation. To produce separation layer 140, internal preparation system 230 generates a laser beam and focuses the laser beam to a focal point (ie, footprint 150) inside workpiece 130. FIG. In other configurations, internal preparation system can generate any other type of incident radiation that can generate footprint 150 within workpiece 130 . Generally, the laser changes the structure of the workpiece 130 at the footprint 150 to locally weaken the material and thereby create favorable locations for crack propagation. The structure of workpiece 130 is substantially unchanged at any location other than footprint 150 . As an example, the internal preparation system 230 can generate an amount of thermal energy at the footprint 150 that melts the material of the workpiece 130 in that area.

An internal preparation system 230 working in conjunction with the positioner 220 creates a footprint 150 within the workpiece 130 along the shear plane 160 . Thus, footprint 150 generally alters the structure of workpiece 130 within shear plane 160 to produce separation layer 140 . Because the structure of the workpiece 130 within the separation layer 140 is different than the structure surrounding the separation layer 140 , the workpiece 130 tends to shear along the plane of the separation layer 140 . The process of producing isolation layer 140 is described in more detail in connection with FIG.

FIG. 3 shows the internal preparation system 230 in more detail. Internal preparation system 230 includes laser source 310 , beam shaper 320 , footprint positioning element 330 , and workpiece shape correction optics 340 .

A laser source 310 produces pulses of radiation at a certain repetition rate. The repetition rate is typically at least 100 kHz, although lower repetition rates are possible. The laser pulses form a collimated symmetrical laser beam. The laser beam has a wavelength longer than the electronic bandgap of the workpiece 130 material so that the workpiece 130 material is not electronically excited when the laser enters the workpiece 130 . Generally, the laser light source 310 has a wavelength, eg, between 0.2 and 20 μm. This allows internal preparation system 230 to produce separation layer 140 for workpiece 130 having an electronic bandgap between, for example, 0.1-10 eV.

In one embodiment, beam shaper 320 produces an asymmetric laser beam. The optics of beam shaper 320 can operate as a cylindrical telescope that produces an asymmetric laser beam. An asymmetric laser beam allows a larger footprint 150 to be produced when focused on the workpiece 130 . Generating a larger footprint 150 from a single pulse allows faster fabrication of the isolation layer 140 with the same laser repetition rate. Asymmetric beams may also allow the creation of thinner separation layers 140 . A thinner separation layer 140 allows shears 250 to shear workpiece 130 using less force, resulting in less roughness on the separated surface. In one embodiment, the long axis of the asymmetric laser beam is parallel to the long axis of workpiece 130 . In another embodiment, the long axis of the asymmetric laser beam is perpendicular to the long axis of workpiece 130 . The laser beam can be re-collimated after beam shaper 320 . For some workpiece geometries, an asymmetric laser beam may not be necessary.

Footprint positioning element 330 focuses the laser beam onto footprint 150 within workpiece 130 . Generally, the geometry of the footprint 150 within the shear plane 160 is configurable, and the thickness of the footprint 150 that determines the thickness of the separation layer 140 is, for example, less than 20 μm, but any other can be the size of In one embodiment, footprint positioning element 330 is a rotationally symmetric, positive focal length optical system. Footprint positioning element 330 is movable along the propagation axis of the laser beam. Movement of footprint positioning element 330 along this axis allows the depth of footprint 150 within workpiece 130 to vary along the same axis.

In one embodiment, workpiece 130 and workpiece shape correction optics 340 can be moved in unison with respect to footprint positioning element 330 to change the depth of footprint 150 within workpiece 130 as well. . In some cases, the depth of footprint 150 within workpiece 130 can be much greater than, for example, 1 mm. The depth of footprint 150 within workpiece 130 is limited only by the optical transmissivity of the workpiece 130 material and laser parameters such as average power, peak power, and wavelength. The material properties of workpiece 130 affect the laser parameters (ie, wavelength, peak power, average power) that enable creation of footprint 150 within workpiece 130 . For example, a laser having a first wavelength is used to create a footprint on a workpiece of a first material, and a laser having a second wavelength is used to create a similar footprint on a workpiece of a second material. can be generated. Other examples are possible.

Workpiece shape correction optics 340 corrects the shape of the surface of workpiece 130 to reduce the effects of aberrations, such as astigmatism, for various positions of footprint positioning element 330 so that footprints 150 in workpiece 130 are aligned. maintain the fluence required to generate Workpiece shape correction optics 340 may include multiple elements to correct a single aberration or many aberrations. This optical system may not be necessary depending on the shape of the workpiece.

Overall, internal preparation system 230 and positioner 220 are configured to create footprint 150 at any location within workpiece 130 . Additionally, the configuration of internal preparation system 230 controls the shape and dimensions of footprint 150 . For example, one configuration of internal preparation system 230 produces footprints 150 that are 4 μm×20 μm ellipses in isolation layer 140 , while another configuration produces footprints 150 that are 20 μm diameter circles in isolation layer 140 . . As mentioned above, the thickness of footprint 150 is determined primarily by the configuration of beam shaper 320 and footprint positioning element 330, but is generally less than 20 μm.

Internal preparation system 230 may have several other optical combinations that function similarly. For example, refractive optics can be replaced by reflective optics (curved mirrors). Beam shaper 320 can be an anamorphic prism pair instead of a cylindrical telescope. Workpiece shape correction optics 340 can replace freeform optics that, in addition to correcting the shape of workpiece 130, help correct for aberrations caused by previous optics.

The external preparation system 240 prepares the workpiece 130 for shearing by scoring the outer surface of the workpiece 130 . Cutting the outer surface of the workpiece 130 causes the workpiece 130 to crack. Shears 250 propagate cracks through workpiece 130 along separation layer 140 to shear workpiece 130 into multiple pieces. Generally, the external preparation system 240 cuts the workpiece 130 at the same location (e.g., coplanar location, coincident location, etc.) as the separation layer 140 where cutting is desired, but at other locations as desired. A notch may be made in the workpiece 130 . The location of the cuts can be a single point, multiple points, a single line, or multiple lines as desired. For example, the cut locations are approximately circumferential scribes along the outer surface of the workpiece 130 . In one embodiment, the functions of external preparation system 240 are performed by some or all of the components of internal preparation system 230 .

External preparation system 240 can cut workpiece 130 in several ways. For example, the external preparation system 240 may laser ablate material from the workpiece 130, physically remove material from the workpiece 130 (with a mechanical scribe, saw, chisel, etc.), The workpiece 130 may be scored by etching the workpiece 130 (such as with a plasma) or any other process capable of scoring the workpiece 130 .

If the external preparation system 240 cuts the workpiece 130 at the same location as the separation layer 140 , the crack can partially propagate around the separation layer 140 by cutting the surface. Partially propagated cracks are further propagated through separation layer 140 when workpiece 130 is sheared. For example, internal preparation system 230 creates separation layer 140 on the (100) plane of silicon workpiece 130 . The external preparation system 240 cuts the silicon workpiece 130 along the perimeter of the separation layer 140 and cracks the (100) plane. Thus, when shears 250 shear silicon workpiece 130, cracks propagate through separation layer 140 along the (100) plane. The extent to which cracks propagate along isolation layer 140 depends on the characteristics of isolation layer 140 (eg, thickness, uniformity, etc.), the method of cutting workpiece 130 (eg, ablation, physical removal, etc.), and the work piece. It depends on the material and orientation (eg, crystallographic direction, composition, etc.) of piece 130 .

Shears 250 shear workpiece 130 into one or more pieces. In one example, shears 250 apply a mechanical pulling force 440 perpendicular to separation layer 140 to shear workpiece 130 . In one embodiment, mechanical pulling force 440 is applied to workpiece 130 via electrostatic clamps 410 attached to opposite ends of workpiece 130 . A voltage 416 is applied between the electrostatic clamp 410 and the workpiece 130 to firmly clamp them. Workpiece 130 is sheared when mechanical pulling force 440 is applied and electrostatic clamp 410 is pulled apart in a controlled manner.

FIG. 4 illustrates an exemplary process of shearing workpiece 130 using shears 250 (eg, capacitive clamp 410). Capacitive clamp 410 includes non-conductive layer 414 and conductive body 412 . A non-conductive layer 414 is positioned proximate to one side of the conductive body 412 . In some embodiments, non-conductive layer 414 is deposited directly on the surface of conductive body 412 such that they are chemically adhered. In many embodiments, the other side of conductive body 412 is secured to some type of support 430 . This can be done by any suitable means for mechanically or chemically fixing or attaching the two materials. If the support 430 is made of metal or other conductive material, by using a non-conductive mounting method, the voltage 416 applied to the conductive body 412 is also applied to the support 430, potentially causing a short circuit. or prevent it from causing other harm. In one embodiment, workpiece 130 may be secured to clamp 420 using epoxy or other type of adhesive, clamp 420 holding the workpiece 130 while clamp 410 repeatedly cuts multiple pieces from workpiece 130 . It can remain permanently fixed to piece 130 . In some embodiments, the shape of capacitive clamp 410 matches the cross-sectional shape of workpiece 130 .

Capacitive clamp 410 secures workpiece 130 by creating an electrostatic force such as that experienced by the plates of a parallel plate capacitor. A voltage supply 416 is used to energize the conductive body 412 to a high voltage while the workpiece 130 is energized to the opposite polarity or grounded. Additionally, the non-conductive layer 414 prevents electrical charges from passing from the conductive body 412 to the workpiece 130 or vice versa. The charge thus collects on the nearest surfaces of both the conductive body 412 and the workpiece 130 . Since these charges are opposite and therefore attracted, an electric field is generated within the non-conductive layer 414 and an associated electrostatic force is also generated.

The strength of the electrostatic force required to secure the workpiece 130 to the capacitive clamp 410 may vary, but the applied compressive stress is typically on the order of 10 ⁶ -10 ⁸ Pa. This stress is typically produced by applying voltage 416 in the range including, but not limited to, 100V to 500 kV, depending on the thickness and dielectric properties of non-conductive layer 414 . For example, a 100 V bias applied to a 100 nm thick HfO ₂ non-conductive layer 414 produces a compressive stress of approximately 10 ⁸ Pa. FIG. Similarly, a 500 kV bias on a 500 μm thick quartz non-conductive layer 414 produces a compressive stress of about 10 ⁷ Pa. FIG. Fracture mechanics analysis indicates that the stress required to propagate crack 404 depends primarily on the initial crack depth and the sharpness of the crack tip. For example, if the crack 404 were partially propagated along the separation layer 140 created by the internal preparation system 230, less force would be required to shear the workpiece 130. FIG. Flexibility in the depth of the initial crack 404 provides flexibility in the required electrostatic force and thus the voltage 416 required for propagation.

The surface finish of capacitive clamp 410 can affect the strength and uniformity of the electrostatic force between capacitive clamp 410 and workpiece 130 . Because air has a lower dielectric constant than the material used for non-conductive layer 414, the air gap between workpiece 130 and non-conductive layer 414 is a It can reduce the electric field present and reduce the resulting electrostatic force. In addition, randomly positioned air gaps can affect the uniformity of the electric field between the conductive body 412 and the workpiece 130, resulting in reduced electrostatic force uniformity. To reduce such effects, the contact surface of non-conductive layer 414 is made as atomically flat as possible (eg, using methods such as polishing) so that capacitive clamp 410 and workpiece 130 are in contact with each other. can reduce the presence of air between Polishing may also prevent damage to the workpiece 130 if the material used for the non-conductive layer 414 is harder than 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, conductive body 412 is composed of a semiconductor material.

The material used for non-conductive layer 414 can affect the operation of capacitive clamp 410 due to the amount of electrostatic force required to shear workpiece 130 . In order for capacitive clamp 410 to function like a capacitor, non-conductive layer 414 should be a dielectric material. The magnitude of the electric field at which these materials break down or lose their insulating properties is known as the dielectric strength. Using materials with high dielectric strength is advantageous because the electric field experienced by the non-conductive layer 414 is proportional to the electrostatic force generated by the capacitive clamp. Materials known to withstand electric fields of the required magnitude include diamond, cubic boron nitride, aluminum nitride, hafnium oxide, silicon oxide, silicon nitride, niobium oxide, barium titanate, strontium titanate, and niobate. Lithium, aluminum oxide, calcium fluoride, silicon carbide, and any combination thereof. However, this list is not meant to be limiting, as other materials with similarly high dielectric strength may also work for this purpose. A secondary dielectric material consideration is the dielectric constant. Higher values of dielectric constant require lower voltages, and thus reduce the electric field that needs to be applied to achieve the same amount of electrostatic force. Therefore, the ideal material to use for non-conductive layer 414 is one that has both high dielectric strength and high dielectric constant.

In some embodiments, the dielectric material used for non-conductive layer 414 is coated with thin layers of different materials. If the dielectric material is too hard to damage the workpiece 130 during clamping, the thin coating can be a softer dielectric material that does not damage the workpiece 130 . If the dielectric is too soft and is damaged during clamping, the thin coating can be a harder dielectric material that will withstand the forces associated with clamping.

Workpiece Although the system is particularly applicable to semiconductor manufacturing, the workpiece 130 may be made of materials other than semiconductor materials. In various embodiments, the workpiece 130 is such that when a voltage 416 is applied between the workpiece 130 and the conductive body 412 charge can flow to the surface of the workpiece 130 mating with the capacitive clamp 410 . It should be conductive or semi-conductive as possible. Examples of workpiece 130 materials that meet these requirements include many semiconductors such as silicon, silicon carbide, indium phosphide, gallium phosphide, germanium, gallium arsenide, gallium nitride, and the like. If the material used for workpiece 130 is not sufficiently conductive to meet these requirements, less electrostatic force will be generated and capacitive clamp 410 will clamp workpiece 130 as strongly as necessary for the shearing process. It may not be fixed. However, these properties can still be achieved with workpieces 130 made of insulating materials such as silicon oxide, aluminum oxide, zirconium oxide, and magnesium oxide. For example, in one embodiment, the shaper 210 can apply a thin conductive coating strongly bonded to the surface of the insulating material. To be considered strongly bonded, a thin conductive coating must remain bonded to the surface of the insulating material during the application of the electrostatic and tensile forces used in the shearing process.

The placement of isolation layer 140 within workpiece 130 can determine the crystallographic orientation of the resulting wafer. In many embodiments, isolation layer 140 is aligned with a particular crystallographic plane within workpiece 130 . Thus, the crystallographic orientation of the resulting wafer will match the selected crystallographic plane. Standard crystal orientations of crystalline silicon include (100), (111), and (110).

System Controller In various embodiments, system controller 120 controls various elements of shearing system 110 to shear workpiece 130 .

System controller 120 determines the shape of workpiece 130 based on the desired shape of the sheared piece. For example, if the desired shape of the sheared piece is circular, controller 120 controls shaper 210 to shape workpiece 130 into a cylindrical shape. In one embodiment, the system controller 120 further controls the optional cropper 260 subsystem to crop the sheared pieces to the final desired geometric shape. In general, controlling shaper 210 involves generating electrical signals to control various elements of shaper 210 capable of shaping workpiece 130 . Similarly, controlling the cropper 260 includes generating electrical signals to control various elements of the cropper 260 that are capable of cutting the sheared pieces into a particular final geometric shape.

System controller 120 determines the positions of workpiece 130, external preparation system 240, and internal preparation system 230 while workpiece 130 is being prepared for shearing and being sheared. Determining the position may include determining the spatial position of the workpiece 130 or elements of the shearing system 110 such that the shearing surface 160 of the workpiece 130 is illuminated by the internal preparation system 230 . Once the positions are determined, system controller 120 can generate control signals for positioners 220 that position workpiece 130 or elements of shear system 110 . Similarly, system controller 120 can generate control signals to cause positioner 220 to position shear system 110 or any other element of workpiece 130 .

System controller 120 determines and regulates the operating characteristics of internal provisioning system 230 . In one example, system controller 120 determines and adjusts the characteristics of the laser beam emitted by laser source 310 . One or more of the laser beam properties can be determined based on, for example, the properties of the workpiece 130, the position of the separation layer 140, and the like. Laser light source 310 and laser beam characteristics may include wavelength, power, pulse rate, and the like. Additionally, system controller 120 can determine and adjust the appropriate positions of various optical elements to produce footprint 150 and isolation layer 140 within workpiece 130 . The optics can be further configured to control the size, shape, and position of footprint 150 .

System controller 120 determines and regulates the operating characteristics of external provisioning system 240 . In one example, the system controller 120 determines and adjusts the positions of the workpiece 130 and the external preparation system 240 when cutting the outside of the workpiece 130 . System controller 120 can also determine and adjust the depth, width, and overall shape of cracks to be introduced.

System controller 120 controls the operation of shears 250 . That is, the system controller generates the voltages and signals necessary for shears 250 to shear workpiece 130 . In one embodiment, system controller 120 controls shears 250 based on the capacitive clamp design shown in FIG.

Shearing Process FIG. 5 is a flow diagram of a process 500 for shearing workpiece 130 using shearing system 110 .

System controller 120 determines the shape of workpiece 130 based on the desired shape of the sheared piece. Based on the determined shape, shaper 210 shapes 510 workpiece 130 into the desired shape. For example, if shaped workpiece 130 is expected to be square, shaper 210 may shape workpiece 130 into a square shape with the geometric specifications and tolerances necessary to successfully complete the remainder of the shearing process. Mold into a prism (510).

System controller 120 determines the position of shear plane 160 within workpiece 130 . Internal preparation system 230 internally prepares workpiece 130 by creating separation layer 140 at a desired shear plane 160 within workpiece 130 (520). In some cases, internal preparation system 230 creates multiple separation layers 140 within workpiece 130 . These processes are described in more detail in connection with FIG.

System controller 120 determines where to crack workpiece 130 . External preparation system 140 externally prepares workpiece 130 by creating an outer surface crack 404 that propagates through workpiece 130 along separation layer 140 when sheared (530). Generally, cracks 404 are along the perimeter or part of the boundary of separation layer 140 prepared by internal preparation system 230 . In some cases, external preparation system 140 introduces several cracks 404 along the outer surface of workpiece 130 .

System controller 120 generates a signal for shears 250 to shear 540 workpiece 130 . In one embodiment, shearing the workpiece 130 includes propagating a crack 404 along the separation layer 140 by creating a mechanical pulling force 440 across the workpiece 130 . That is, the workpiece 130 is sheared by separating the workpiece 130 into two pieces at the separating layer 140 . Generally, the workpiece 130 is sheared so that the shear plane is perpendicular to the long axis of the workpiece 130 . In another embodiment, shearing of the workpiece 130 is achieved by applying a controlled shear force to the workpiece such that cracks 404 are preferentially propagated along the separation layer 140 . to propagate crack 404 . In yet another embodiment, the shearing of the workpiece 130 includes compressing, tensioning, shearing, bending, twisting, or compressing the interior of the workpiece 130 such that cracks 404 preferentially propagate along the separation layer 140 . Propagating the crack 404 by creating a general mechanical stress consisting of a variable combination of fatigue stresses is included. In yet another embodiment, the shearing (540) of the workpiece 130 includes applying a thermal stress that can be achieved by rapidly heating or cooling the workpiece 130, thereby propagating the crack 404 along the separation layer 140. is included. In yet another embodiment, the workpiece 130 is sheared (540) by applying a powerful vibration that can be achieved through a piezoelectric actuator, magnetostrictive actuator, or similar device that produces a powerful sound wave within the workpiece 130. , propagating the crack 404 along the isolation layer 140 . In yet another embodiment, shearing (540) of workpiece 130 can be accomplished by any combination of the above methods.

The system can shear 540 the workpiece 130 multiple times. In various embodiments, this may include internal preparation (520) of the workpiece 130, external preparation (530) of the workpiece, and shearing (540) of the workpiece 130 any number of times. These steps may occur in different orders and may be repeated multiple times based on the configuration of shear system 110 .

Internal Preparation FIG. 6 is a flow diagram of a process 600 for preparing workpiece 130 internally using internal preparation system 230 .

Here, system controller 120 has determined shear plane 160 of workpiece 130 . Thus, system controller 120 configures 610 internal preparation system 230 to produce separation layer 140 at desired shear plane 160 within workpiece 130 . The configuration of the internal preparation system 230 includes positioning the optics, positioning the workpiece 130, parameters of the laser source 310 so that the internal preparation system 230 produces the appropriate footprint 150 in the workpiece 130 and the like.

System controller 120 then controls laser source 310 to project a laser beam toward workpiece 130 (620). The laser beam is focused into workpiece 130 by various optics of internal preparation system 230 . The laser beam creates 630 a footprint 150 within the workpiece 130 along the desired shear plane 160, altering the structure of the workpiece 130 in that area.

An example of internally preparing a workpiece 130 for shearing by creating 630 a footprint 150 is shown in FIGS. 7A and 7B. 7A is an isometric view of workpiece 130 during internal preparation, and FIG. 7B is a cross-sectional view of workpiece 130 during internal preparation.

In this example, the workpiece 130 is a cylindrical ingot because the cut pieces are expected to be circular. Shear plane 160 is perpendicular to the longitudinal axis of workpiece 130 . Laser beam 710 is incident on the surface of workpiece 130 and focused onto footprint 150 . Footprint 150 is coplanar with shear plane 160 or oriented similarly to shear plane 160 .

Returning to FIG. 6, system controller 120 reconfigures internal provisioning system 230 (610). In this example, configuring the internal preparation system 230 includes repositioning the optics such that the footprint 150 in the workpiece 130 is at a different location on the shear plane 160 . Once the internal preparation system 230 is reconfigured, the system controller 120 projects a focused beam (620) to generate a new footprint 150 (630). This process is illustrated in Figures 7C and 7D.

In particular, although FIGS. 7A-7D show an example in which the direction of propagation of the laser beam used to internally prepare the workpiece 130 is perpendicular to the long axis of the workpiece 130, the direction of the laser beam Other examples of are also possible. For example, the direction of propagation of the laser beam can be parallel to the long axis of the workpiece. In this case, the laser beam is incident on the workpiece from the top surface of the workpiece instead of from the side of the workpiece.

The process of creating footprint 150 continues iteratively until footprint 150 as a whole creates isolation layer 140 . FIG. 8A shows an example footprint 150 forming a separation layer 140 on a sheared surface 160 of a workpiece 130. FIG. Shear plane 160 is equal to the plane of the page. In other embodiments, the isolation layer 140 can have different footprint 150 densities. That is, in some examples, footprints 150 may have some overlap or additional spacing between footprints 150 . In addition, the system controller 120 can use a particular pattern of footprints 150 to generate the isolation layer 140 . For example, system controller 120 may map footprints 150 using a raster pattern from one side to the other, a pattern that starts in the center and spirals outward, a pattern that forms concentric rings of footprints 150, and the like. can be generated. Whatever the pattern and density, footprint 150 creates isolation layer 140 . 8B and 8C show isometric cross-sectional views of isolation layer 140. FIG.

Returning to FIG. 6, system controller 120 determines the position of another separation layer 140 . As such, system controller 120 causes positioner 220 to reposition workpiece 130 and/or internal preparation system 230 to create another separation layer 140 . In general, positioner 250 moves workpiece 130 along its longitudinal axis to position workpiece 130 to produce another separation layer 140 parallel to first separation layer 140 (640). Once workpiece 130 and internal preparation system 230 are properly positioned, internal preparation system 230 produces another separation layer 140 . An example of a workpiece 130 after producing multiple separation layers 140 is shown in FIG. The distance between the separating layers 140 indicates the thickness of the shear strip produced after shearing. The distance between separation layers may be limited by the thickness of separation layer 140 . For example, the separating layer may have a thickness t', and the distance between the centers of two adjacent separating layers in the workpiece is, for example, greater than t'. Typically, the thickness of the wafers produced is greater than 10 μm, but may be less than 10 μm. In another embodiment, multiple isolation layers 140 are fabricated in parallel in such a way that previous footprints 150 do not interfere in the creation of new footprints 150 .

FIG. 10A shows an example of workpiece 130 sheared along separating layer 140 . Workpiece 130 is sheared into upper piece 1010 and lower piece 1030 along separation layer 140 , which in this example is coplanar with shear plane 160 . Here, the bottom surface 1020 of the top piece 1010 was on the isolation layer 140 . Similarly, top surface 1040 of bottom piece 1030 was on isolation layer 140 .

FIG. 10B shows an example of a workpiece 130 that has been sheared along several separation layers 140. FIG. In this example, the workpiece is sheared into top piece 1050 , middle piece 1060 and bottom piece 1070 . The previously bonded surfaces were at the shear plane 160 and the coplanar separation layer 140 . In various embodiments, shearing system 110 can shear workpiece 130 into any number of pieces. Each segment can have any desired thickness based on the proximity of separation layer 140 and shear surface 160 .

The foregoing description of embodiments of the invention has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Those skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

Finally, the terminology used herein has been chosen primarily for readability and instructional purposes and may not be chosen to describe or limit the subject matter of the present invention. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of embodiments of the invention is intended to illustrate, but not limit, the scope of the invention, which is set forth in the following claims.

Claims (20)

A method for shearing a workpiece of material, said method comprising:
using a laser generated by an internal preparation system to create a separation layer within the workpiece having different material properties than the rest of the workpiece;
determining a position of a shear plane within the workpiece using a controller;
using a positioner to position the workpiece so that the shear plane and the separation layer are coincident;
using an external preparation system to score the workpiece to create a crack in the outer surface of the workpiece at at least one point coinciding with the separation layer;
shearing the workpiece using a shear to create a sheared piece by creating a tensile force in the workpiece perpendicular to at least a portion of the separating layer that propagates the crack along the separating layer; a method comprising generating; 2. The method of claim 1, wherein the method comprises:
The method further comprising forming the workpiece into the defined geometric shape using a forming system such that the shear strip has a boundary equal to a cross-section of the defined geometric shape. 2. The method of claim 1, wherein creating the separating layer comprises:
A method further comprising focusing the laser onto a footprint within the workpiece, wherein the pulses of the laser locally alter material properties of the workpiece at the footprint. 2. The method of claim 1, wherein creating the separating layer comprises:
moving the focal point of the laser within the workpiece to produce the decoupling layer, the decoupling layer being a locally altered layer of material at the focal point as it moves within the workpiece; The method further comprising forming as an aggregate. 2. The method of claim 1, wherein shearing the workpiece comprises:
attaching the shears to both ends of the workpiece;
generating a tensile force that propagates the crack along the separation layer, the tensile force being generated perpendicular to at least a portion of the separation layer across the workpiece; How to include. 6. The method of claim 5 , wherein the shears are electrostatically attached to opposite ends of the workpiece. 2. The method of claim 1, wherein the method comprises:
The method further comprising using a cropper to cut said shear strip into a particular geometric shape. 2. The method of claim 1, wherein the method comprises:
The method further comprising using the laser to create another separation layer with different material properties in the workpiece. 9. The method of claim 8 , wherein the method comprises:
The method further comprising using the shears to shear the workpiece along the separate separation layer to produce another sheared piece. 2. The method of claim 1, wherein the laser is a pulsed laser and the internal preparation system produces laser pulses at a repetition rate of at least 100 kHz. A system for shearing a workpiece of material, said system comprising:
An internal preparation system configured to generate a laser beam to create a separation layer within the workpiece, the separation layer having different material properties than the rest of the workpiece. When,
a controller configured to determine the position of a shear plane within the workpiece;
a positioner configured to position the workpiece such that the shear plane and the separation layer are coincident;
an external preparation system configured to score the workpiece so as to create a crack in the surface of the workpiece at at least one point coinciding with the separation layer;
Shears configured to generate a sheared piece of the workpiece by applying a tensile force to the workpiece perpendicular to at least a portion of the separating layer that propagates the crack along the separating layer. and a system comprising: 12. The system of claim 11 , wherein the system comprises:
The system further comprising a shaper configured to shape the workpiece into the defined geometric shape such that the sheared piece has a boundary equal to a cross-section of the defined geometric shape. 12. The system of Claim 11 , wherein the internal provisioning system comprises:
The system further comprising a focusing system configured to focus a laser onto a footprint within the workpiece, wherein pulses of the laser locally alter material properties of the workpiece at the footprint. 12. The system of Claim 11 , wherein the internal provisioning system comprises:
further comprising a focusing system configured to move a focal point of a laser within the workpiece to produce the separation layer, the separation layer being locally displaced at the focal point as it is moved within the workpiece; A system formed as an aggregate of altered materials. 12. The system of claim 11 , wherein the shears are further attached to opposite ends of the workpiece and configured to generate a tensile force that propagates the crack along the separating layer, wherein the A system in which a tensile force is generated perpendicular to at least a portion of the separation layer across the workpiece. 16. The system of Claims 1-5 , wherein the shears are configured to be electrostatically attached to opposite ends of the workpiece. 12. The system of claim 11 , wherein the system comprises:
The system further comprising a cropper configured to cut the sheared pieces into a particular geometric shape. 12. The system of Claim 11 , wherein the internal preparation system is further configured to use a laser to create another separation layer having different material properties within the workpiece. 19. The system of claim 18 , wherein the shears are further configured to shear the workpiece along the separate separation layer to produce another sheared piece. 12. The system of claim 11 , wherein the laser beam produced by the internal preparation system is a pulsed laser beam having pulses produced at a repetition rate of at least 100 kHz.

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