Wafer chamfering method and processing device

Abstract

A wafer chamfering method and device, the wafer chamfering method comprising: providing a wafer to be processed; generating a laser beam by a laser; forming the incident laser beam into a central low-energy region and a high-energy region located at the periphery of the central low-energy region by a beam shaping device; adjusting the size of the high-energy region by the beam shaping device according to the thickness of the wafer to be processed and the target chamfering profile; and rotating the wafer to be processed and the laser beam relative to each other around a rotation axis to synchronously remove material from the corner regions of the upper surface edge and the lower surface edge of the wafer to be processed, thereby forming a continuous chamfering profile on the entire periphery of the wafer to be processed. The present application forms a specific light field with a central low-energy region and a peripheral high-energy region, and rotates the wafer to be processed and the laser beam relative to each other to synchronously remove material from the upper and lower surface edges of the wafer, thereby achieving one-step forming, non-contact, high efficiency and low damage processing of the hard and brittle wafer periphery chamfering.

Description

Technical Field

[0001] This application relates to the field of wafer processing technology, specifically to a wafer chamfering processing method and processing apparatus. Background Technology

[0002] In the semiconductor manufacturing field, the chamfering of the outer periphery of hard and brittle wafer materials such as silicon carbide, diamond, and sapphire, which are wide or ultra-wide bandgap semiconductors, is a key step in ensuring device reliability.

[0003] In related technologies, wafer chamfering primarily relies on diamond wheel contact grinding. The grinding wheel wears rapidly during continuous processing, making it difficult to maintain a stable wheel profile. This leads to a significant deterioration in the consistency of chamfer radius, angle, and edge roughness. Meanwhile, existing laser chamfering technology, as an alternative, typically employs complex operations such as oscillating the laser incident angle, tilting the wafer orientation, five-axis linkage control, layered scanning strategies, multiple laser cutting sequences, or laser roughing followed by wheel finishing to achieve chamfering. These methods fail to provide a highly efficient, stable, and scalable one-step wafer chamfering process. Summary of the Invention

[0004] The purpose of this application is to provide a wafer chamfering processing method and apparatus to solve the problems of poor wafer chamfering contour consistency and low processing efficiency.

[0005] To achieve the objectives of this application, the following technical solution is provided: In a first aspect, this application provides a wafer chamfering process, comprising: Provide wafers to be processed; A laser beam is generated by using a laser. The incident laser beam is formed into a central low-energy region and a high-energy region surrounding the central low-energy region by a beam shaping device, such that the energy density of the central low-energy region is lower than the material removal threshold of the wafer to be processed, and the energy density of the high-energy region is higher than the material removal threshold of the wafer to be processed. Based on the thickness of the wafer to be processed and the target chamfer profile, the size of the high-energy region is adjusted by the beam shaping device so that the high-energy region matches the target chamfer region of the wafer to be processed. The wafer to be processed is rotated relative to the laser beam about a rotation axis, and the optical axis of the laser beam forms an angle with the surface of the wafer to be processed, so that the high-energy region forms a continuous processing band on the entire outer periphery of the wafer to be processed, so as to simultaneously remove material from the corner areas of the upper and lower surface edges of the wafer to be processed, thereby forming a continuous chamfer profile on the entire outer periphery of the wafer to be processed.

[0006] In one embodiment, the wavelength, pulse width, repetition frequency, and single-pulse energy of the laser beam are configured such that the energy density of the high-energy region is higher than the material removal threshold of the wafer to be processed.

[0007] In one embodiment, the beam shaping device employs at least one of a spatial light modulator, a diffractive optical element, a digital micromirror device, an axonocone, a vortex phase plate, an annular aperture, and a compound lens group.

[0008] In one embodiment, the high-energy region is in the shape of a complete circular ring, an elliptical ring, multiple rings, or a semi-ring.

[0009] In one embodiment, the incident laser beam is formed into an annular flat-top beam comprising a central low-energy region and a high-energy region located around the central low-energy region by the beam shaping device, so that the high-energy region is a complete ring. The inner diameter, outer diameter and radial width of the high-energy region are adjusted according to the thickness of the wafer to be processed and the target chamfer profile.

[0010] In one embodiment, the outer diameter of the high-energy region corresponds to the thickness of the wafer to be processed, and the inner diameter and radial width of the high-energy region are positively correlated with the target chamfer profile of the wafer to be processed.

[0011] In one embodiment, the beam shaping device can adjust the size, position, and energy density of the high-energy region in real time according to the thickness and edge runout of the wafer to be processed.

[0012] In one embodiment, the wafer chamfering method further includes: Clean gas is sprayed onto the outer periphery of the wafer to be processed by a blowing mechanism to blow away molten material, particles or dust from the wafer, and then collected by negative pressure pumping.

[0013] Secondly, this application also provides a wafer chamfering processing apparatus, applied to the wafer chamfering processing method according to any one of the various embodiments of the first aspect, the wafer chamfering processing apparatus comprising: The support mechanism includes a support platform, a rotating shaft, and a driving component. One end of the rotating shaft is connected to the output end of the driving component, and the other end of the rotating shaft is connected to the support platform. The support platform is used to support the wafer to be processed. Laser, used to generate laser beams; A beam shaping device is disposed between the support stage and the laser, and the beam shaping device forms the incident laser beam into a central low-energy region and a high-energy region located around the central low-energy region; An air blowing mechanism, comprising an air supply component and a nozzle connected to the air supply component, wherein the nozzle is disposed above the support platform and the nozzle is inclined from the center of the support platform to the edge from top to bottom; The main controller is electrically connected to the drive unit, laser, beam shaping device and gas supply unit.

[0014] In one embodiment, the wafer chamfering processing apparatus further includes a beam expanding and collimating mechanism, a focusing mechanism, and a processing head. The beam expanding and collimating mechanism is disposed between the laser and the beam shaping device. The beam shaping device, the focusing mechanism, and the processing head are arranged sequentially. The center of the processing head is aligned with the center of the wafer to be processed on the support stage in the thickness direction.

[0015] Compared with the prior art, this application has at least the following beneficial effects: 1. In this application, the incident laser beam can be formed into a specific optical field with a central low-energy region and a high-energy region located around the central low-energy region by a beam shaping device. The energy density of the central low-energy region is lower than the material removal threshold of the wafer to be processed, and the energy density of the high-energy region is higher than the material removal threshold of the wafer to be processed. That is, the high-energy region at the edge of the laser beam is used to simultaneously remove material from the corner regions of the upper and lower surface edges of the wafer, while the central low-energy region is used to avoid effective material removal from the middle of the outer periphery of the wafer. This achieves one-time forming, non-contact, high-efficiency and low-damage processing of the outer periphery chamfer of hard and brittle wafers. 2. In this application, the size of the high-energy region can be adjusted as needed by the beam shaping device to accurately match the target chamfer profile of wafers of different thicknesses, avoiding the positioning deviation that is easy to occur in traditional mechanical grinding and improving the wafer chamfer accuracy; 3. In this application, the wafer to be processed and the laser beam are rotated relative to each other around a rotation axis, and the optical axis of the laser beam forms an angle with the surface of the wafer to be processed, so that the high-energy region forms a continuous processing band on the entire outer periphery of the wafer to be processed, thereby forming a continuous chamfer profile on the entire outer periphery of the wafer to be processed. The continuous and unbroken chamfer profile can significantly reduce microcracks at the wafer edge, avoid thermal stress defects from diffusing into the wafer interior during subsequent high-temperature processes, and improve the uniformity of the distribution of epitaxial layer and photoresist at the wafer edge. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart of a wafer chamfering process according to one embodiment of this application; Figure 2 This is a schematic diagram of the structure of a wafer chamfering processing apparatus according to one embodiment of this application; Figure 3 This is a characteristic curve of the distribution of laser beam energy density along the laser beam diameter according to one embodiment of this application; Figure 4 This is a schematic diagram of the laser beam energy distribution according to one embodiment of this application; Figure 5 This is a schematic diagram of the structure of the wafer to be processed and the laser beam according to one embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 100. Wafer to be processed; 200. Support mechanism; 210. Support stage; 220. Rotating shaft; 300. Laser; 310. Laser beam; 311. Central low-energy region; 312. High-energy region; 400. Beam shaping device; 500. Nozzle; 600. Main controller; 700. Beam expanding and collimating mechanism; 800. Focusing mechanism; 900. Processing head. Detailed Implementation

[0019] The following are specific embodiments of this application, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of this application. However, this application is not limited to these embodiments.

[0020] refer to Figures 1-5 This application provides a wafer chamfering process, comprising: Step S100: Provide the wafer 100 to be processed; Step S200: A laser beam 310 is generated by laser 300; In step S300, the incident laser beam 310 is formed into a central low-energy region 311 and a high-energy region 312 located around the central low-energy region 311 by the beam shaping device 400, and the energy density of the central low-energy region 311 is lower than the material removal threshold of the wafer 100 to be processed, and the energy density of the high-energy region 312 is higher than the material removal threshold of the wafer 100 to be processed. In step S400, based on the thickness of the wafer 100 to be processed and the target chamfer profile, the size of the high-energy region 312 is adjusted by the beam shaping device 400 so that the high-energy region 312 matches the target chamfer region of the wafer 100 to be processed. In step S500, the wafer 100 to be processed and the laser beam 310 are rotated relative to each other around a rotation axis, and the optical axis of the laser beam 310 is made at an angle with the surface of the wafer 100 to be processed, so that the high-energy region 312 forms a continuous processing band on the entire outer periphery of the wafer 100 to be processed, so as to simultaneously remove material from the corner areas of the upper and lower surface edges of the wafer 100 to be processed, thereby forming a continuous chamfer profile on the entire outer periphery of the wafer 100 to be processed.

[0021] The beam shaping device 400 optically processes the original laser beam 310 generated by the laser 300, altering its energy distribution to meet specific processing requirements. The beam shaping device 400 reshapes the incident laser beam 310 into a shape with a specific energy distribution. The central low-energy region 311 refers to the area where, after processing by the beam shaping device 400, the energy density of the central portion of the laser beam 310 is lower than the material removal threshold of the wafer 100 to be processed. In other words, the laser energy in the central low-energy region 311 is insufficient to effectively remove the wafer material, thus protecting the central area of ​​the wafer from processing. The high-energy region 312 refers to the area where, after processing by the beam shaping device 400, the energy density of the peripheral portion of the laser beam 310 is higher than the material removal threshold of the wafer 100 to be processed. The laser energy in this high-energy region 312 is sufficient to effectively remove the wafer material, making it the effective area for actual chamfering processing.

[0022] Wafer materials may include 4H-SiC, 6H-SiC, 3C-SiC, diamond, sapphire, GaN, AlN, Ga2O3, AlGaN, glass ceramics, and oxide crystals.

[0023] The material removal threshold refers to the minimum energy density required for effective removal of 100% of the material from the wafer under laser irradiation. When the laser energy density is below this threshold, the material will not be removed; when it is above this threshold, the material begins to be removed.

[0024] The target chamfer profile refers to the desired edge geometry of the wafer after chamfering, including parameters such as chamfer radius, angle, and depth. This profile is the design target during the processing, guiding the beam shaping device 400 to adjust the size of the high-energy region 312. The continuous processing zone refers to a ring-shaped or strip-shaped processing area formed by the high-energy region 312 on the outer periphery of the wafer. Through the relative rotation of the wafer and the laser beam 310, this processing zone can cover the entire outer periphery of the wafer, achieving continuous material removal. This allows the high-energy region 312 to simultaneously remove material from the corner areas of both the upper and lower surface edges of the wafer in a single laser strike, improving wafer processing efficiency and ensuring the consistency of the chamfer profile.

[0025] In the wafer chamfering method of this embodiment, firstly, step S100 requires providing a wafer 100 to be processed. The wafer can be placed on a support stage 210 and fixed by vacuum adsorption or mechanical clamping to ensure stability during the processing.

[0026] Subsequently, step S200 generates a laser beam 310 using laser 300. This laser 300 can be a pulsed laser 300, such as a femtosecond, picosecond, nanosecond, quasi-continuous, or continuous laser 300. Its wavelength, pulse width, repetition frequency, and single-pulse energy can be initially set according to the material properties of the wafer 100 to be processed and the processing efficiency requirements. The wavelength can be selected from the ultraviolet, visible, near-infrared, or mid-infrared bands depending on the material.

[0027] Next, in step S300, the incident laser beam 310 is processed using a beam shaping device 400. This beam shaping device 400 can reshape the energy distribution of the original laser beam 310, forming a central low-energy region 311 and a high-energy region 312 surrounding the central low-energy region 311. For example, this specific energy distribution can be generated by incorporating a combination of optical elements with specific transmission or reflection characteristics in the optical path, such as a combination of a ring aperture and a lens group. During this process, it is necessary to ensure that the energy density of the central low-energy region 311 is below the material removal threshold of the wafer 100 to be processed, while the energy density of the high-energy region 312 is above this material removal threshold. That is, the laser energy in the central region is insufficient to damage the wafer, while the laser energy in the peripheral region is sufficient to effectively remove the wafer material.

[0028] Furthermore, in step S400, the size of the high-energy region 312 is adjusted by the beam shaping device 400 according to the thickness of the wafer 100 to be processed and the target chamfer profile. For example, the radial width or diameter of the high-energy region 312 can be changed by replacing optical elements of different sizes or by manually adjusting the relative positions between optical elements, so that it can be geometrically matched with the target chamfer area of ​​the wafer 100 to be processed, ensuring that the laser energy can be precisely applied to the area that needs to be chamfered.

[0029] Finally, in step S500, the wafer 100 to be processed and the laser beam 310 are rotated relative to each other around a rotation axis. Simultaneously, the optical axis of the laser beam 310 forms an angle with the surface of the wafer 100 to be processed, which can be 0 degrees. For example, the wafer can be fixed on a rotating stage and rotated, while the incident direction of the laser beam 310 can be radial side incident, near-radial oblique incident, end-face projection incident, or spatial folding incident achieved through a mirror / prism, as long as the high-energy region 312 matches the target chamfer region. Through the relative rotation of the wafer 100 to be processed and the laser beam 310 and the fixed incident angle of the laser beam 310, the high-energy region 312 can form a continuous processing band on the entire outer periphery of the wafer 100 to be processed. Thus, the high-energy region 312 can simultaneously act on the corner regions of the upper and lower surface edges of the wafer 100 to be processed, achieving synchronous material removal, thereby forming a continuous chamfer profile on the entire outer periphery of the wafer in one operation.

[0030] The wafer chamfering method of this embodiment employs a special laser beam 310 with a central low-energy region 311 and a peripheral high-energy region 312. By precisely adjusting the size of the high-energy region 312 according to the wafer thickness and the target chamfer profile, simultaneous material removal is achieved from the edge corners of the upper and lower surfaces of the wafer. This method avoids the damage and contamination introduced by traditional grinding wheels, simplifies the complex motion control and multi-step processing of existing laser chamfering schemes, and enables one-time, non-contact, high-efficiency, and low-damage chamfering of the outer periphery of hard and brittle wafers without relying on multi-axis linkage and frequent adjustments, forming a continuous chamfer profile.

[0031] Furthermore, the wavelength, pulse width, repetition frequency, and single-pulse energy of the laser beam 310 are configured such that the energy density of the high-energy region 312 is higher than the material removal threshold of the wafer 100 to be processed.

[0032] Specifically, different wafer materials (such as silicon, silicon carbide, gallium arsenide, etc.) have different absorption characteristics for laser beams of different wavelengths 310. Selecting a wavelength that matches the absorption peak of the material in the wafer to be processed 100 can maximize the absorption efficiency of the laser energy, thereby reaching the material removal threshold at a lower single-pulse energy and reducing energy waste and thermal damage. For example, for silicon wafers, near-infrared or ultraviolet lasers are selected. The pulse width determines the timescale of the laser-material interaction. Ultrashort pulses (such as picosecond or femtosecond lasers) have extremely high peak power, enabling energy deposition into the material in a very short time, leading to direct vaporization or sublimation of the material with a minimal heat-affected zone in the surrounding area. In contrast, nanosecond or microsecond pulsed lasers produce more significant thermal effects. The repetition rate refers to the number of laser pulses emitted per unit time. A higher repetition rate can provide more energy input in the same amount of time, thereby improving processing efficiency and material removal rate. Single-pulse energy is the energy carried by a single laser pulse. By precisely controlling the single-pulse energy, it can be ensured that each pulse achieves effective material ablation or vaporization in the target area, while avoiding unnecessary damage to non-processed areas. The ultimate goal of configuring the above laser parameters is to ensure that the energy density of the high-energy region 312 is higher than the material removal threshold of the wafer 100 to be processed. The material removal threshold is the minimum energy density required for a specific material to begin permanent removal (such as ablation or vaporization) at a specific laser wavelength and pulse width.

[0033] By precisely configuring the wavelength, pulse width, repetition frequency, and single-pulse energy of the laser beam 310, it can be ensured that the energy density of the high-energy region 312 formed by the beam shaping device 400 is stably and effectively higher than the material removal threshold of the wafer 100 to be processed. This ensures that the material removal process is stable and uniform when a continuous processing band is formed on the entire outer periphery of the wafer, avoiding incomplete processing due to insufficient energy or wafer damage due to excessive energy, thereby significantly improving the quality and efficiency of wafer chamfering.

[0034] The beam shaping device 400 employs at least one of the following: spatial light modulator (SLM), diffractive optical element (DOE), digital micromirror device (DMD), axial cone, vortex phase plate, annular aperture, and compound lens group.

[0035] Specifically, a spatial light modulator is a device capable of real-time modulation of the spatial phase, amplitude, or polarization state of a light beam. By loading a specific hologram or phase map onto the spatial light modulator, the incident laser beam 310 can be flexibly shaped into a specific spot with a central low-energy region 311 and a peripheral high-energy region 312. Furthermore, the size, shape, and energy distribution of the high-energy region 312 can be dynamically adjusted to adapt to different chamfering requirements. A diffractive optical element is an optical element that uses the principle of light diffraction to change the characteristics of a light beam. By etching microstructures on a substrate, a diffractive optical element can reshape the incident laser beam 310 into a preset complex optical field, such as a ring-shaped spot. A digital micromirror device (DMD) is a semiconductor device composed of a large array of independently flippable micromirrors. The high-speed flipping of the micromirror array achieves spatial amplitude modulation of the incident beam; when combined with a specific diffractive optical path, equivalent phase or complex amplitude modulation can also be achieved, thereby forming the desired laser spot. DMDs are characterized by high speed and programmability, enabling rapid switching between different spot modes and providing dynamic adaptability for chamfering processes.

[0036] An axial cone is a conical lens whose main function is to convert a Gaussian beam into a nearly diffraction-free Bessel beam. This beam has a long focal line in its propagation direction, and its cross-section is typically annular. By adjusting the parameters of the axial cone or combining it with other optical elements, the diameter and thickness of the annular spot can be controlled, thereby forming a laser beam 310 with a central low-energy region 311 and a peripheral high-energy region 312. A vortex phase plate is an optical element that can introduce a helical phase into the incident beam, thereby generating a vortex beam with orbital angular momentum. A vortex beam is characterized by a region with zero intensity at its center (optical vortex), while the energy is concentrated in the outer annular region. By selecting vortex phase plates with different topological charges, the size and energy distribution of the annular spot can be controlled to achieve the desired structure of low energy at the center and high energy at the periphery. An annular aperture is a physical aperture with an annular light-passing region. When the laser beam 310 passes through the annular aperture, its central part is blocked, and only the outer annular part passes through, thus directly forming an annular spot. A compound lens group is an optical system composed of multiple lenses of different types and focal lengths. By carefully designing the arrangement and parameters of the lenses, a compound lens group can achieve complex beam shaping of a laser beam 310, including converting a Gaussian beam into a ring beam with a specific energy distribution. This combination method provides a high degree of design freedom, enabling high-precision and high-efficiency beam shaping.

[0037] These devices provide diverse beam shaping capabilities, enabling the laser beam 310 to precisely form a specific spot with a central low-energy region 311 and a peripheral high-energy region 312. Specifically, programmable or tunable devices, such as spatial light modulators and digital micromirrors, can dynamically adjust the size, shape, and energy distribution of the high-energy region 312 in real time according to the thickness of the wafer 100 and the target chamfer profile. This ensures that the high-energy region 312 precisely matches the target chamfer region of the wafer 100, avoiding problems such as uneven processing or insufficient / excessive material removal caused by spot mismatch. Diffractive optical elements, axial cones, vortex phase plates, and compound lens groups provide efficient and stable specific annular spot generation schemes, meeting the requirements of spot stability and efficiency in different processing scenarios. This flexibility and precision significantly improve the adaptability and processing quality of wafer chamfering, ensuring the formation of a continuous and uniform chamfer profile across the entire wafer periphery, effectively avoiding wafer edge chipping and defects, and improving wafer yield and reliability.

[0038] The high-energy region 312 can be a complete circular ring, an elliptical ring, a multi-ring, or a semi-ring. Specifically, when the high-energy region 312 is a complete circular ring, it can be achieved using various beam shaping devices 400, such as using an axonocone combined with a lens system, a specific diffractive optical element (DOE), or a spatial light modulator (SLM). When the high-energy region 312 is an elliptical ring, it can be generated by adjusting the phase or amplitude distribution on the spatial light modulator, or by designing a diffractive optical element with elliptical symmetry. When the high-energy region 312 is a multi-ring, it can consist of multiple concentric or non-concentric ring regions, each with a different energy density or width. This multi-ring structure enables more complex chamfer profiles, such as forming multi-level chamfers at once, or achieving fine energy distribution control within the chamfered region. The multi-ring shape can be achieved by superimposing multiple ring beams, using complex diffractive optical elements, or by programming the spatial light modulator. When the high-energy region 312 is in the shape of a semi-ring, it is suitable for chamfering a local area of ​​the wafer. The semi-ring shape can be achieved by introducing an obstruction in the optical path, or by precisely generating a semi-ring spot through a spatial light modulator or diffractive optical element.

[0039] By providing high-energy regions 312 in various shapes such as complete rings, elliptical rings, multi-rings, or semi-rings, the processing method can flexibly select and adjust the energy distribution shape of the laser beam 310 according to the specific geometric features, material properties, and complexity of the target chamfer profile of the wafer 100 to be processed. This makes laser chamfering no longer limited to a single spot shape, thus enabling more precise and efficient fulfillment of various complex chamfering requirements. It effectively overcomes the limitations of traditional methods in dealing with diverse chamfering needs, improving processing quality and production efficiency.

[0040] In this regard, this application further proposes to form an annular flat-top beam including a central low-energy region 311 and a high-energy region 312 located around the central low-energy region 311 by using a beam shaping device 400 to shape the incident laser beam 310 into an annular flat-top beam, so that the high-energy region 312 is a complete ring. The inner diameter, outer diameter and radial width of the high-energy region 312 are adjusted according to the thickness of the wafer 100 to be processed and the target chamfer profile.

[0041] Specifically, the annular flat-top beam refers to a laser beam 310 whose energy distribution on the radial cross-section exhibits a central low-energy region 311 and an outer high-energy region 312, with the energy density of the high-energy region 312 remaining relatively uniform within a certain range (i.e., "flat-top" characteristic). This beam is achieved through a beam shaping device 400, such as a spatial light modulator, diffractive optical element, or axial cone, to convert the Gaussian-distributed laser beam 310 into a beam with a specific annular flat-top profile. This ensures uniform energy input within the processing area, avoiding processing quality differences caused by uneven energy distribution, thereby achieving a smoother and more consistent material removal effect. Setting the shape of the high-energy region 312 as a complete annulus ensures continuous and uniform chamfering at the corners of the upper and lower surface edges of the wafer, avoiding processing blind spots or discontinuous chamfer profiles, thus guaranteeing chamfer quality and wafer mechanical strength. The inner diameter refers to the inner boundary diameter of the annular high-energy region 312, the outer diameter refers to its outer boundary diameter, and the radial width refers to the radial thickness of the annular high-energy region 312. By precisely adjusting these parameters, the contact area between the laser beam 310 and the wafer 100 to be processed can be finely controlled. For example, by adjusting the inner and outer diameters, the position of the chamfer can be directly controlled; by adjusting the radial width, the width of the chamfer in the wafer thickness direction can be directly controlled.

[0042] In this application, the outer diameter of the high-energy region 312 corresponds to the thickness of the wafer 100 to be processed, and the inner diameter and radial width of the high-energy region 312 are positively correlated with the target chamfer profile of the wafer 100 to be processed.

[0043] Specifically, the outer diameter of the high-energy region 312 corresponds to the thickness of the wafer 100 to be processed, aiming to ensure that the laser energy can effectively cover the entire edge thickness of the wafer 100, thereby achieving simultaneous material removal from the upper and lower surface edges of the wafer. For example, for a specific wafer material and laser processing parameters, an optimal ratio of outer diameter to wafer thickness can be determined, or a parameter lookup table can be constructed. When the wafer thickness changes, the beam shaping device 400 can precisely adjust the outer diameter of the high-energy region 312 according to this correspondence to ensure that the laser's effective range always completely covers the entire side of the wafer, avoiding processing defects caused by insufficient or excessive coverage. This correspondence can be linear or a nonlinear relationship determined according to actual processing requirements and material properties.

[0044] Meanwhile, the inner diameter and radial width of the high-energy region 312 are positively correlated with the target chamfer profile of the wafer 100 to be processed, used to precisely control the shape and size of the chamfer profile. The inner diameter primarily determines the position of the chamfer initiation point relative to the wafer edge, while the radial width directly affects the chamfer's slope, depth, or width. This positive correlation means that when the target chamfer profile requires a wider, deeper, or specific curvature, the inner diameter of the high-energy region 312 may decrease accordingly (to be closer to the wafer center), while the radial width will increase accordingly to provide sufficient energy to form the desired chamfer shape. For example, if the target chamfer profile is a large arc chamfer, a larger radial width and a relatively smaller inner diameter may be required. The beam shaping device 400 can dynamically or pre-set the inner diameter and radial width of the high-energy region 312 according to preset chamfer profile parameters (such as chamfer radius, chamfer angle, chamfer depth, etc.) to achieve precise matching for different chamfer designs.

[0045] Furthermore, the beam shaping device 400 can adjust the size, position, and energy density of the high-energy region 312 in real time according to the thickness and edge runout of the wafer 100 to be processed.

[0046] Specifically, the beam shaping device 400 is a key component for altering the spatial energy distribution of the laser beam 310. In this embodiment, it not only shapes the incident laser beam 310 into a specific spot with a central low-energy region 311 and a peripheral high-energy region 312, but also possesses dynamic tunability. The beam shaping device 400 can rapidly and precisely change its shaping effect on the laser beam 310 based on external feedback signals. The beam shaping device 400 that achieves this dynamic adjustment can include, but is not limited to, deformable mirrors based on microelectromechanical systems (MEMS), spatial light modulators (SLMs), programmable diffractive optical elements (DOEs), or composite optical systems incorporating fast-scanning mirrors. For example, a spatial light modulator can control the phase or amplitude distribution of its liquid crystal pixel array via electrical signals, thereby changing the energy distribution, size, and position of the emitted laser beam 310 in real time.

[0047] The thickness of the wafer 100 to be processed is a key parameter affecting the chamfering geometry. Even minute changes in wafer thickness directly influence the relative position and angle of the laser beam 310 with the wafer edge. For example, if the wafer thickness increases while the laser beam 310's position remains unchanged, the high-energy region 312 may not completely cover the target chamfer area, or it may act on a non-target area. Therefore, accurately sensing and responding to changes in wafer thickness in real time is a prerequisite for ensuring consistent chamfer contours. Wafer thickness can be monitored in real time using online measurement sensors (such as laser displacement sensors or capacitive sensors).

[0048] Edge runout refers to the radial or axial deviation of the wafer's edge relative to its ideal rotation trajectory during rotation. This runout can be caused by geometric defects in the wafer itself, the mounting accuracy of the wafer 100 to be processed, or vibrations during rotation. Edge runout causes a momentary shift in the relative point of action between the laser beam 310 and the wafer edge. Without compensation, this will result in uneven processing strip width, discontinuous chamfer profiles, or local overcutting / undercutting. Edge runout can be detected in real time using non-contact sensors such as high-speed vision systems, laser rangefinders, or eddy current sensors.

[0049] During wafer fabrication, laser processing parameters are dynamically changed based on real-time data fed back by sensors. Sensors (such as thickness sensors and edge runout sensors) acquire real-time data, and controllers (such as main controller 600) calculate the required adjustment amount according to a preset algorithm and send instructions to beam shaping device 400 to change the size, position, and energy density of high-energy region 312 in a very short time (e.g., multiple adjustments within one rotation of the wafer).

[0050] The dimensional adjustment of the high-energy region 312 addresses changes in wafer thickness or target chamfer profile. This is achieved by altering the radial width or inner / outer diameter (e.g., annular spot) of the high-energy region 312 to ensure it consistently matches the geometry of the target chamfer area. For example, as wafer thickness increases, the radial width of the high-energy region 312 may need to be increased to cover a wider chamfer area. The positional adjustment of the high-energy region 312 addresses wafer edge runout. This is achieved by fine-tuning the center position of the high-energy region 312 radially or axially to ensure the laser beam 310 is always precisely aligned with the actual edge of the wafer. For example, when the wafer edge runs outward, the high-energy region 312 needs to be moved outward to maintain alignment. The energy density adjustment of the high-energy region 312 addresses minute changes in material removal efficiency or wafer material properties. This is achieved by altering the laser power or energy distribution of the high-energy region 312 to ensure the stability of material removal rate and quality. For example, when the wafer material removal threshold changes slightly, the energy density can be fine-tuned to maintain optimal processing results.

[0051] Therefore, this application can significantly improve the accuracy and stability of wafer chamfering, ensuring the formation of a highly uniform and continuous chamfer profile that meets design requirements on the entire outer periphery of the wafer, thereby improving the yield and reliability of the wafer.

[0052] In this regard, this application further proposes that the wafer chamfering processing method also includes: step S600, spraying clean gas onto the outer periphery of the wafer 100 to be processed through a blowing mechanism to blow away the molten material, particles or dust from the wafer 100 to be processed, and collecting them through negative pressure pumping.

[0053] Specifically, an air blowing mechanism is a device used to generate and guide airflow, its core function being to provide a stream of clean gas with a certain pressure and velocity. This mechanism typically includes an air source, a flow and pressure control unit, and one or more nozzles 500. The air source provides a stable gas supply, the control unit ensures the gas is output with preset parameters, and the nozzles 500 are responsible for precisely guiding the gas to the target area, forming a concentrated airflow. In wafer chamfering, the air blowing mechanism should be configured to ensure that its ejected airflow effectively covers the laser processing area and its vicinity, in order to promptly remove contaminants generated during the processing.

[0054] The clean gas can be air, nitrogen, argon, helium, oxygen, or a reactive auxiliary gas, and can be used in conjunction with negative pressure suction, water mist cooling, or local inert protection.

[0055] The system sprays clean gas onto the periphery of the wafer 100 to be processed, using the kinetic energy of the airflow to blow away processing residues from the wafer surface. Nozzles 500 are angled to the processing edge of the wafer to maximize the purging effect. Negative pressure suction is used to ensure that the blown-away contaminants do not diffuse into the environment or redeposit on other areas of the wafer. The system consists of a suction port, connecting pipes, a filter, and a negative pressure pump.

[0056] During wafer chamfering, the air blowing mechanism continuously sprays clean gas onto the periphery of the wafer 100 to be processed. This clean airflow effectively and promptly removes molten material, particles, or fumes generated during laser processing from the wafer surface, preventing the redeposition of these processing residues on the wafer surface or processed areas, thus significantly reducing the risk of surface contamination. Simultaneously, in conjunction with a negative pressure suction collection system, the blown-off contaminants are rapidly captured and removed, preventing their diffusion into the processing environment, further ensuring the cleanliness of the processing area and maintaining the stability and precision of laser processing.

[0057] Optionally, depending on the wafer material and application requirements, low-energy laser cleaning, plasma cleaning, wet cleaning, chemical mechanical polishing, or light edge polishing steps can be added, mainly to remove small amounts of redeposited material, reduce surface roughness, or meet specific device-level surface quality requirements.

[0058] This application uses a one-step chamfering process for a 4H-SiC wafer as an example for illustration: A 4H-SiC wafer with a thickness of 350–800 μm is selected, and sharp edges exist on the outer periphery after slicing or grinding. The wafer is adsorbed and fixed on an air bearing rotating spindle, and the radial runout of the outer circumference of the wafer is controlled within 10–30 μm. A nanosecond pulsed laser 300 with a wavelength of 532 nm and a pulse width of 1–10 ns is used. After beam expansion, collimation, and SLM phase modulation, the laser beam 310 forms a ring-shaped flat-top beam with a central low-energy region 311 and an outer ring high-energy region 312.

[0059] The repetition frequency of the laser beam 310 is set to 20–100 kHz, and the single-pulse energy is set to 20–150 μJ. Based on the wafer thickness and target chamfer size, the outer diameter of the high-energy region 312 is adjusted to 400–900 μm, the inner diameter to 300–750 μm, and the ring width to 30–80 μm. The energy density of the high-energy region 312 is higher than the effective removal threshold of 4H-SiC, while the energy density of the central low-energy region 311 is lower than the effective removal threshold. The energy of the laser beam 310 is adjusted according to the size of the high-energy region 312, the beam shaping efficiency, and the material removal status at the wafer edge.

[0060] During processing, a laser beam 310 is fixedly irradiated around the outer periphery of the wafer in a radial or near-radial direction, with the center of the laser beam 310 located near the center of the wafer thickness. Upper and lower high-energy rings cover the edge corners of the upper and lower surfaces of the wafer, respectively, while the central low-energy region 311 corresponds to the center of the wafer's side surface. The wafer rotates continuously at a constant speed, with the outer periphery linear velocity set to 20–100 mm / s. The high-energy region 312 simultaneously removes material from the upper and lower edges of the wafer, forming a chamfered profile that is approximately R-shaped or has a bevel-arc transition. During processing, nitrogen gas or clean, dry air at a pressure of 0.1–0.3 MPa is used to purge the laser-affected area to reduce the redeposition of processing debris and molten material. The wafer rotates 1–5 times to complete a full chamfer, and the amount of material removed is controlled by adjusting the single-pulse energy, repetition frequency, ring spot size, rotational linear velocity, and number of rotations. Using the above parameters, double chamfers with a width of 30 to 100 μm can be formed simultaneously on the entire outer periphery of the wafer, while keeping the middle part of the wafer side basically intact.

[0061] Furthermore, for chamfering of diamond wafers, an ultraviolet or short-pulse laser beam 310 can be used, and a ring-shaped high-energy region 312 can be generated through DOE or SLM. Due to the high hardness of diamond and severe wear of the grinding wheel, this method utilizes the non-contact ring-shaped high-energy region 312 to directly process the wafer edge, reducing chamfer morphology drift caused by grinding wheel contour wear. By reducing the single-pulse heat input, increasing the repetition frequency, and using inert gas purging, edge thermal impact and graphitization deposition can be reduced. If necessary, low-energy purging or short-time chemical cleaning can be performed after one-time chamfering to remove the surface deposited layer.

[0062] This application embodiment also provides a wafer chamfering processing apparatus, applied to the above-described wafer chamfering processing method. The wafer chamfering processing apparatus includes a support mechanism 200, a laser 300, a beam shaping device 400, an air blowing mechanism, and a main controller 600.

[0063] The support mechanism 200 includes a support platform 210, a rotating shaft 220, and a driving component. One end of the rotating shaft 220 is connected to the output end of the driving component, and the other end of the rotating shaft 220 is connected to the support platform 210. The support platform 210 is used to support the wafer 100 to be processed. The laser 300 generates a laser beam 310. The beam shaping device 400 is disposed between the support platform 210 and the laser 300. The beam shaping device 400 forms a central low-energy region 311 and a high-energy region 312 located around the central low-energy region 311 from the incident laser beam 310. The air blowing mechanism includes an air supply component and a nozzle 500 connected to the air supply component. The nozzle 500 is disposed above the support platform 210 and is inclined from the center of the support platform 210 to the edge from top to bottom. The main controller 600 is electrically connected to the driving component, the laser 300, the beam shaping device 400, and the air supply component.

[0064] Specifically, the stage 210 is connected to the drive unit via the rotating shaft 220, enabling the wafer 100 to be processed to rotate stably around the rotating shaft 220. The beam shaping device 400 is configured to reshape the incident laser beam 310 into a specific energy distribution with a central low-energy region 311 and a peripheral high-energy region 312, wherein the energy density of the central low-energy region 311 is lower than the material removal threshold of the wafer 100 to be processed, while the energy density of the high-energy region 312 is higher than the threshold, thereby ensuring that only the target chamfered area is accurately removed.

[0065] In practical applications, the laser beam 310 generated by the laser 300 is processed by the beam shaping device 400. The size of the high-energy region 312 is adjusted according to the thickness of the wafer 100 to be processed and the target chamfer profile, so that it is geometrically matched with the target chamfer region. At the same time, the optical axis of the laser beam 310 forms a fixed angle with the surface of the wafer 100 to be processed. Combined with the rotational movement of the support stage 210, the high-energy region 312 forms a continuous processing band on the outer periphery of the wafer, realizing synchronous material removal at the upper and lower surface edges. Furthermore, the nozzle 500 of the air blowing mechanism is inclined from the center of the support stage 210 to the edge from top to bottom. Clean gas is sprayed onto the outer periphery of the wafer through the air supply component, effectively blowing away molten material, particles, or dust from the processing area. The dust is then absorbed and collected by negative pressure to avoid secondary contamination.

[0066] The main controller 600 coordinates the control of the drive unit, laser 300, beam shaping device 400, and gas supply components to ensure the accuracy and stability of the processing. Compared with traditional solutions, this embodiment eliminates the need for five-axis linkage, laser angle oscillation, or wafer attitude adjustment, simplifying the equipment structure and control logic. Simultaneously, the central low-energy region 311 avoids damage to the wafer's central area, the precise matching of the high-energy region 312 ensures the consistency of the chamfer profile, and the air-blowing design of the tilting nozzle 500 significantly reduces the risk of heat-affected zones and particle residue. Overall, this wafer chamfering processing device achieves efficient, stable, and scalable one-step chamfering of the outer periphery of hard and brittle wafers, effectively solving the problems of low processing efficiency, difficult damage control, and high process complexity in existing technologies.

[0067] In one embodiment, the wafer chamfering apparatus further includes a beam expanding and collimating mechanism 700, a focusing mechanism 800, and a processing head 900. The beam expanding and collimating mechanism 700 is disposed between the laser 300 and the beam shaping device 400. The beam shaping device 400, the focusing mechanism 800, and the processing head 900 are arranged sequentially, and the center of the processing head 900 is aligned with the center of the wafer 100 to be processed on the support stage 210 in the thickness direction.

[0068] Specifically, the beam expanding and collimating mechanism 700 is used to expand the diameter of the laser beam 310 and collimate it, i.e., reduce the beam divergence angle and keep the beam parallel during transmission. This mechanism typically consists of one or more lenses, such as a combination of a diverging lens and a converging lens. Its function is to ensure that the laser beam 310 has a stable spot size and good collimation before entering the beam shaping device 400, providing high-quality incident light for subsequent beam shaping and focusing. This helps to improve the utilization rate of laser energy and the stability of processing. The focusing mechanism 800 is used to focus the beam-shaped laser beam 310 onto a specific area of ​​the wafer 100 to be processed. This mechanism typically consists of one or more lenses, such as an F-theta lens or a flat-field scanning lens. Its function is to precisely focus the shaped laser beam 310 onto the edge area of ​​the wafer 100 to achieve the required energy density and realize effective material removal. The accuracy of the focusing mechanism 800 directly affects the fineness of the processing and the accuracy of the chamfer profile. The processing head 900 is the end effector of an integrated optical component (such as the focusing mechanism 800) in a laser processing system. The processing head 900 includes a focusing lens and can integrate a fine-tuning mechanism for adjusting the focal length and beam position. Its function is to accurately guide the processed laser beam 310 to the processing point on the wafer 100 to be processed, maintaining a stable working distance and angle.

[0069] The beam expanding and collimating mechanism 700 is positioned between the laser 300 and the beam shaping device 400, ensuring that the original laser beam 310 emitted from the laser 300 is pre-aligned to ideal size and collimation before entering the beam shaping device 400. Pre-collimation ensures that the beam shaping device 400 can stably generate the required central low-energy region 311 and high-energy region 312. The shaped beam is then precisely focused by the focusing mechanism 800 and finally guided to the processing area by the processing head 900, ensuring precise control and transmission of laser energy, thereby achieving efficient and high-precision chamfering.

[0070] By aligning the center of the processing head 900 with the center of the wafer 100 to be processed on the stage 210 in the thickness direction, this application can ensure that the laser beam 310 removes material simultaneously and symmetrically at the upper and lower edges of the wafer, thereby forming a continuous, uniform and high-quality chamfer profile on the entire outer periphery, significantly improving the accuracy and consistency of wafer chamfering.

[0071] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0072] Furthermore, the use of terms such as "first," "second," and "a" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0073] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0074] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

Claims

1. A wafer chamfering process, characterized in that, include: Provide wafers to be processed; A laser beam is generated by using a laser. The incident laser beam is formed into a central low-energy region and a high-energy region surrounding the central low-energy region by a beam shaping device, such that the energy density of the central low-energy region is lower than the material removal threshold of the wafer to be processed, and the energy density of the high-energy region is higher than the material removal threshold of the wafer to be processed. Based on the thickness of the wafer to be processed and the target chamfer profile, the size of the high-energy region is adjusted by the beam shaping device so that the high-energy region matches the target chamfer region of the wafer to be processed. The wafer to be processed is rotated relative to the laser beam about a rotation axis, and the optical axis of the laser beam forms an angle with the surface of the wafer to be processed, so that the high-energy region forms a continuous processing band on the entire outer periphery of the wafer to be processed, so as to simultaneously remove material from the corner areas of the upper and lower surface edges of the wafer to be processed, thereby forming a continuous chamfer profile on the entire outer periphery of the wafer to be processed.

2. The wafer chamfering method according to claim 1, characterized in that, The wavelength, pulse width, repetition frequency, and single-pulse energy of the laser beam are configured such that the energy density of the high-energy region is higher than the material removal threshold of the wafer to be processed.

3. The wafer chamfering method according to claim 1, characterized in that, The beam shaping device employs at least one of the following: a spatial light modulator, a diffractive optical element, a digital micromirror device, an axial cone, a vortex phase plate, an annular aperture, and a compound lens group.

4. The wafer chamfering method according to claim 1, characterized in that, The high-energy region can be a complete circular ring, an elliptical ring, a multi-ring, or a semi-ring.

5. The wafer chamfering method according to claim 4, characterized in that, The incident laser beam is formed into a ring-shaped flat-top beam by the beam shaping device, which includes a central low-energy region and a high-energy region located around the central low-energy region. The high-energy region is shaped into a complete ring. The inner diameter, outer diameter and radial width of the high-energy region are adjusted according to the thickness of the wafer to be processed and the target chamfer profile.

6. The wafer chamfering method according to claim 5, characterized in that, The outer diameter of the high-energy region corresponds to the thickness of the wafer to be processed, and the inner diameter and radial width of the high-energy region are positively correlated with the target chamfer profile of the wafer to be processed.

7. The wafer chamfering method according to claim 1, characterized in that, The beam shaping device can adjust the size, position, and energy density of the high-energy region in real time according to the thickness and edge runout of the wafer to be processed.

8. The wafer chamfering method according to claim 1, characterized in that, The wafer chamfering process further includes: Clean gas is sprayed onto the outer periphery of the wafer to be processed by a blowing mechanism to blow away molten material, particles or dust from the wafer, and then collected by negative pressure pumping.

9. A wafer chamfering processing apparatus, characterized in that, The wafer chamfering process method according to any one of claims 1 to 8, wherein the wafer chamfering apparatus comprises: The support mechanism includes a support platform, a rotating shaft, and a driving component. One end of the rotating shaft is connected to the output end of the driving component, and the other end of the rotating shaft is connected to the support platform. The support platform is used to support the wafer to be processed. Laser, used to generate laser beams; A beam shaping device is disposed between the support stage and the laser, and the beam shaping device forms the incident laser beam into a central low-energy region and a high-energy region located around the central low-energy region; An air blowing mechanism, comprising an air supply component and a nozzle connected to the air supply component, wherein the nozzle is disposed above the support platform and the nozzle is inclined from the center of the support platform to the edge from top to bottom; The main controller is electrically connected to the drive unit, laser, beam shaping device and gas supply unit.

10. The wafer chamfering apparatus according to claim 9, characterized in that, The wafer chamfering processing apparatus further includes a beam expanding and collimating mechanism, a focusing mechanism, and a processing head. The beam expanding and collimating mechanism is located between the laser and the beam shaping device. The beam shaping device, the focusing mechanism, and the processing head are arranged in sequence. The center of the processing head is aligned with the center of the wafer to be processed on the support stage in the thickness direction.

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