A method and device for atomic level removal of hard and brittle materials based on the freeze-sticking effect

Abstract

The application discloses a kind of hard and brittle material atomic level removal method and device based on freeze sticking effect.First, surface pretreatment and termination state control are carried out on hard and brittle material sample, plasma treatment is used for hydrophilic modification for non-hydrophilic material, the sample is placed in low-temperature experimental cavity and the temperature of sample stage and interface region is controlled by liquid nitrogen passage, water medium is introduced between sample surface and hard alloy loading head by loading head internal microchannel, the thickness of interface water layer and the adhesion state of water molecules are controlled, quasi-liquid layer and freeze sticking layer are formed by gradient cooling, interface temperature, incubation time, water layer thickness and loading parameters are determined by local removal experiment, the determined parameters are introduced into low-temperature ultrasonic traveling wave field ultra-precision machining device, ultrasonic traveling wave excitation is applied, and hard alloy loading head is driven to implement atomic level removal on microconvex structure of sample surface under the mediation of freeze sticking layer.The application breaks through the problem that termination state construction under super-smooth condition is easily affected by ion bombardment and recontamination.

Description

Technical Field

[0001] This invention relates to the field of ultra-precision machining, specifically to a method and apparatus for atomic-level removal of hard and brittle materials based on the freeze-adhesion effect. This invention is applicable to atomic-level precision machining of semiconductor materials and high-hardness, brittle materials. Background Technology

[0002] Atomic-level manufacturing, as a crucial development direction in high-end manufacturing technology, is continuously driving technological advancements in fields such as information technology, aerospace, energy devices, and quantum technology. In semiconductor manufacturing, as chips approach the atomic scale, interface quality has become a key factor determining their performance. Compared to additive manufacturing technologies such as atomic layer deposition and cluster beam deposition, subtractive manufacturing of hard and brittle materials lags significantly behind, with removal amounts mostly remaining at the nanometer or submicron level. This makes it difficult to achieve truly precise atomic-level removal, becoming a critical weakness in atomic-level manufacturing systems.

[0003] For typical hard and brittle materials such as silicon and silicon carbide, existing atomic-level removal methods include chemical mechanical polishing (CMP), ion beam processing, and magnetorheological polishing (MRP). CMP achieves planarization by forming an easily removable reaction layer on the surface, but its processing effect depends on interfacial chemical reactions and mass transport processes, limiting its stability. While ion beam processing can achieve fine machining of micro- and nano-structures, it easily introduces surface damage and amorphization problems. MRP relies on flexible grinding heads to achieve sub-nanometer deterministic removal, but it is still a contact or semi-contact processing method involving abrasive particles, with complex interfacial interactions. Existing atomic-level removal methods for hard and brittle materials generally suffer from significant thermodynamic nonlinear effects and unavoidable byproducts. Their development lags behind additive manufacturing technologies such as atomic layer deposition (ALD) and cluster beam deposition, becoming a key factor restricting the achievement of the three essential elements of atomic-level manufacturing. Therefore, how to achieve low-temperature, clean, and precise removal of workpiece surfaces without introducing thermal damage and secondary contamination is a pressing technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing an atomic-level removal method and apparatus for hard and brittle materials based on the freeze-bonding effect. This method involves modifying the termination state and hydrophilicity of the surface of hard and brittle materials such as silicon and silicon carbide, and using an ultrasonic traveling wave excitation-driven cemented carbide loading head to remove the material from the sample surface at the atomic level with low damage.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] An atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect includes the following steps:

[0007] Step 1: Clean the surface of the hard and brittle material sample and pre-treat the sample surface.

[0008] Step 2: Modify the surface of the hard and brittle material sample by controlling the termination state and hydrophilicizing it according to the surface properties of the sample.

[0009] Step 3: Place the hard and brittle material sample into the low-temperature experimental chamber, and control the temperature of the sample stage and interface area through the liquid nitrogen cooling module.

[0010] Step 4: Introduce an aqueous medium between the sample surface and the loading head through a microchannel set inside the loading head, control the thickness of the interfacial water layer and the adhesion state of water molecules, and form a quasi-liquid layer and a freeze-bonded layer.

[0011] Step 5: Conduct localized removal experiments within the liquid nitrogen temperature range to control the thickness and distribution of the frozen layer.

[0012] Step 6: Adjust the interface temperature and holding time parameters to characterize the interface adhesion and surface lattice structure changes.

[0013] Step 7: Place the hard and brittle material sample in the low-temperature ultrasonic traveling wave field ultra-precision machining device and introduce the process parameters determined by the local removal experiment.

[0014] Step 8: Apply ultrasonic traveling wave excitation to drive the cemented carbide loading head to perform atomic-level material removal on the sample surface under the guidance of the frozen adhesive layer.

[0015] Furthermore, in step 1, the hard and brittle material sample is subjected to multi-stage chemical cleaning and ultrapure solvent treatment to remove contaminants from the sample surface.

[0016] Furthermore, in step 2, an ultra-smooth silicon carbide sample with non-hydrophilic properties that has undergone atomic-level polishing is selected as the modification substrate; the sample surface is subjected to termination state modulation and hydrophilic modification using downstream plasma treatment.

[0017] Furthermore, the plasma generation region is separated from the sample reaction region; a low-polarity hydrogen-terminated surface is constructed on the sample surface using downstream hydrogen and argon plasmas; a controlled thin oxide layer and hydroxylation structure are introduced on the sample surface using downstream oxygen plasmas; and the plasma processing power is adjusted. Processing time Parameters such as these are used to control the hydrogen termination state coverage of the sample surface. for:

[0018]

[0019] in, For saturation coverage, This is a rate constant related to the flow rate.

[0020] The oxide layer thickness on the sample surface Represented as:

[0021]

[0022] in, For adjustment coefficients, and The relevant processing power was determined experimentally. and processing time The exponential factor.

[0023] Hydroxyl site density on the sample surface Represented as:

[0024]

[0025] in, The number of hydroxyl sites on the sample surface. The surface area is the area of ​​action.

[0026] Furthermore, static water contact angle measurements were used to characterize the changes in hydrophilicity of the sample surface.

[0027] Furthermore, in step 3, the hard and brittle material sample is mounted on the sample stage, and the sample stage and interface area are cooled and controlled by the liquid nitrogen cooling module; a sealed structure is set in the low-temperature experimental chamber, and the temperature conditions in the interface area are adjusted by closed-loop control.

[0028] Furthermore, in step 4, an aqueous medium is introduced between the sample surface and the loading head through a microchannel set inside the cemented carbide loading head; the amount of aqueous medium introduced, the interface coverage range, and the thickness of the interface water layer are controlled; a gradient cooling method is used to allow the interface region to slowly cross the preset key temperature zone near the freezing point, forming a quasi-liquid layer and a frozen adhesive layer between the sample surface and the loading head, and the thickness, distribution state, and contact area of ​​the frozen adhesive layer are controlled.

[0029] Furthermore, the material of the cemented carbide loading head is selected and set according to the material type of the hard and brittle material sample. When the sample is a silicon sample, the loading head is a tungsten carbide loading head; when the sample is a silicon carbide sample, the loading head is a tungsten-cobalt cemented carbide loading head.

[0030] Furthermore, step 5 establishes low-temperature micro-area removal experimental conditions within the liquid nitrogen temperature range, and sets parameters for the uniformity of the frozen-adhesive layer thickness. Represented as:

[0031]

[0032] in, The average thickness of the frozen bond layer. This represents the standard deviation of the frozen bond layer thickness.

[0033] Furthermore, the loading direction is adjusted by a precision centering mechanism to make the loading direction consistent with the interface normal, and a normal load is applied to the sample surface by the loading head to carry out the local removal experiment.

[0034] Further, in step 6, the interface parameters and loading parameters are adjusted, the interface peeling force is measured and the interface adhesion work is calculated; the atomic structure of the sample surface is observed in situ to obtain the lattice constant and interatomic spacing distribution of the material surface, and the lattice structure changes in the clean surface and frozen-bonded interface state are compared.

[0035] Furthermore, step 7, the low-temperature ultrasonic traveling wave field ultra-precision machining device, includes a medium supply and temperature control module, an ultrasonic traveling wave machining module, a relative motion and loading module, and a negative pressure flow field control and chip removal module.

[0036] The medium supply and temperature control module supplies a fluid medium to the processing surface area of ​​the workpiece and applies a low temperature field to the processing surface area, causing the fluid medium to solidify in situ on the workpiece surface to form a solid frozen adhesive layer, which fills the micro-uneven structure of the workpiece surface.

[0037] The ultrasonic traveling wave processing module, disposed on one side of the workpiece surface, includes an elastomer stator and a piezoelectric excitation unit coupled to the elastomer stator. The piezoelectric excitation unit includes a piezoelectric ceramic array bonded to the surface of the elastomer stator via a coupling layer. The piezoelectric ceramic array is arranged according to a preset wavelength and phase distribution, used to excite the elastomer stator to generate a bending traveling wave under alternating electric field excitation. The piezoelectric excitation unit is configured to excite the elastomer stator to generate an ultrasonic traveling wave propagating along a preset direction on its surface, causing the surface particles of the elastomer stator to produce an elliptical motion including a tangential component.

[0038] The relative motion and loading module includes a precision motion platform for supporting the workpiece or the ultrasonic traveling wave machining module; and a closed-loop force control unit containing a force sensor and a force actuator for maintaining a constant frictional coupling force during machining. This module is used to adjust the relative position of the two and apply a predetermined pressure to maintain frictional driving contact between the elastomer stator and the frozen adhesive layer.

[0039] The negative pressure flow field control and chip removal module includes: a negative pressure generator connected to the chip removal interface of the ultrasonic traveling wave processing module to provide continuous suction power; and a gas-liquid-solid separator installed in the negative pressure pipeline. When a coaxial integrated jet structure is used, the negative pressure generator is connected to the central negative pressure channel via a pipeline, establishing a low-pressure zone at the center of the processing area, guiding the peripheral fluid medium to converge towards the center, and simultaneously sucking away the low-temperature solid debris after stripping.

[0040] Furthermore, when the ultrasonic traveling wave processing module is working, it drives the frozen adhesive layer to generate shear motion relative to the workpiece surface through frictional coupling between the elastomer stator and the frozen adhesive layer, thereby processing the workpiece surface by utilizing the removal effect of the frozen adhesive layer on the micro-protrusion structure of the workpiece surface.

[0041] Furthermore, the ultrasonic traveling wave processing module is configured in any of the following configurations based on the characteristics of the processing area:

[0042] Rotating traveling wave type: The elastomer stator has a ring or disk-shaped structure, and the piezoelectric excitation unit is configured to excite a traveling wave propagating tangentially in the circumferential direction of the elastomer stator to drive the frozen adhesive layer to generate rotational shear motion.

[0043] Linear traveling wave type: The elastomer stator has a rectangular beam or plate structure, and the piezoelectric excitation unit is configured to excite a traveling wave that propagates axially along the length of the elastomer stator, which is used to drive the frozen bond layer to generate translational shear motion.

[0044] Furthermore, the elastomer stator is made of a high-quality metallic elastic material, and its working surface in contact with the frozen adhesive layer is provided with micro-nano friction-increasing textures; the piezoelectric excitation unit includes a piezoelectric ceramic array bonded to the surface of the elastomer stator through a coupling layer, and the piezoelectric ceramic array is arranged according to a preset wavelength and phase distribution to excite the elastomer stator to generate bending traveling waves under alternating electric field excitation.

[0045] Furthermore, the temperature control unit in the medium supply and temperature control module adopts any of the following structural forms:

[0046] (1) Bottom conduction cooling type: includes a temperature-controlled stage with a refrigerant circulation channel or refrigeration device inside, and the workpiece is fixed on the surface of the temperature-controlled stage; (2) Coaxial integrated jet type: includes a cryogenic fluid channel integrated inside the ultrasonic traveling wave processing module, which is used to directly output low-temperature fluid medium to the processing area.

[0047] Furthermore, the medium supply and temperature control module also includes a medium supply unit, which includes a precision fluid delivery pump and a fluid injection terminal, for uniformly coating the fluid medium onto the workpiece surface in the form of droplets, jets or atomization.

[0048] Furthermore, when the coaxial integrated jet structure is adopted, the cryogenic ultrasonic traveling wave field ultra-precision machining device has a multi-layer coaxial nested structure, which includes, from the inside out: a central negative pressure channel, located on the innermost side of the structure, for absorbing debris and waste liquid from the machining area; an inner heat insulation shield layer, covering the outside of the central negative pressure channel; a cryogenic fluid channel, covering the outside of the inner heat insulation shield layer, for transporting cryogenic refrigerant; an outer heat insulation shield layer, covering the outside of the cryogenic fluid channel; a drive stator assembly, including the elastomer stator and piezoelectric excitation unit, sleeved on the outside of the outer heat insulation shield layer; and a medium supply channel, located on the outermost side of the structure, configured to spray the fluid medium into the machining area. The inner and outer heat insulation shield layers together constitute a dual thermal insulation system, respectively blocking the freezing effect of the cryogenic refrigerant on the central negative pressure channel and the temperature effect on the external drive stator assembly.

[0049] Furthermore, the low-temperature ultrasonic traveling wave field ultra-precision machining method in step 8 includes the following steps:

[0050] Step 8-1: Supply a fluid medium to the surface of the workpiece to be processed and apply a low temperature field to cause the fluid medium to solidify rapidly on the workpiece surface to form a freeze-adhesive layer;

[0051] Step 8-2: Control the ultrasonic traveling wave processing module to press the frozen adhesive layer;

[0052] Step 8-3: Excite the elastomer stator to generate ultrasonic traveling waves, drive the frozen adhesive layer to move tangentially, and use the frozen adhesive layer to remove the micro-protrusion structure on the surface of the workpiece;

[0053] Step 8-4: Remove the frozen adhesive residue containing workpiece material debris.

[0054] Furthermore, prior to step 1, the wettability of the workpiece area to be processed is adjusted and modified with hydrophilicity to improve the spreading ability of the fluid medium on the workpiece surface.

[0055] Furthermore, in steps 1 and 3, the supply rate of the fluid medium and the cooling power of the low-temperature field are controlled to reach a dynamic balance, so that new frozen layers are continuously generated in front of the moving path of the ultrasonic traveling wave processing module, while the frozen layers break or melt behind the processing. During the processing, the negative pressure flow field control and chip removal module is used to establish a negative pressure field in the center of the processing area, guide the fluid medium located on the periphery to converge towards the center, and simultaneously suck away the low-temperature solid debris after peeling, preventing the debris from being recast or remaining.

[0056] The beneficial effects of this invention are as follows:

[0057] 1. This invention modifies the termination state and hydrophilicizes the sample surface, making it suitable for high-hardness, non-hydrophilic hard and brittle materials such as silicon carbide. It overcomes the problem of termination state construction being susceptible to ion bombardment and recontamination under ultra-smooth conditions, enhances the freeze-adhesion ability of interfacial water molecules, improves interfacial stability and consistency during local removal, and reduces the risk of surface damage.

[0058] 2. This invention constructs a controllable quasi-liquid layer and a frozen adhesive layer under liquid nitrogen temperature conditions, adjusts the adhesion state of water molecules at the interface, the hydrogen bond network structure, and the interfacial bonding strength, thereby achieving active control of the interfacial adhesion behavior of hard and brittle materials. This establishes a traceable correlation between process parameters, chemical state, and adhesion performance, providing a stable and controllable basis for the removal of atomic-level materials.

[0059] 3. This invention transforms the interfacial water layer into a controllable tensile stress source through the freeze-bonding effect, and achieves mechanical peeling of the atomic layer by utilizing the directional perturbation of the ultrasonic traveling wave field. In principle, it avoids thermodynamic nonlinear effects and by-product contamination, transforming harmful low-temperature freeze-bonding into a favorable processing method, and providing a completely new pure physical removal path for atomic-level subtractive manufacturing. Attached Figure Description

[0060] Figure 1 This is a flowchart of the atomic-level removal method according to an embodiment of the present invention.

[0061] Figure 2 This is a schematic diagram illustrating the microscopic effects of water molecules on the surface of silicon carbide in different termination states according to an embodiment of the present invention.

[0062] Figure 3 This is a schematic diagram illustrating the principle of hydrophilic modification of silicon carbide surface in an embodiment of the present invention.

[0063] Figure 4 This is a static water contact angle characterization diagram of an embodiment of the present invention.

[0064] Figure 5 This is a schematic diagram of the experimental apparatus for the localized removal of cryogenic freeze-bonded silicon materials according to an embodiment of the present invention.

[0065] Figure 6 This is a schematic diagram of the experimental apparatus for the localized removal of cryogenic freeze-bonded silicon carbide materials according to an embodiment of the present invention.

[0066] Figure 7 This is a schematic diagram of the gradient cooling freeze-bond interface formation process according to an embodiment of the present invention.

[0067] Figure 8 This is a schematic diagram of the structure of the low-temperature ultrasonic traveling wave processing device according to an embodiment of the present invention.

[0068] Figure 9 This is a cross-sectional view of the low-temperature ultrasonic traveling wave processing device according to an embodiment of the present invention.

[0069] Figure 10 This is a flowchart of the low-temperature ultrasonic traveling wave processing method according to an embodiment of the present invention.

[0070] Figure 11 This is a schematic diagram of microscopic interface removal according to an embodiment of the present invention. Detailed Implementation

[0071] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0072] The embodiments of the present invention relate to an atomic-level removal method and apparatus for hard and brittle materials based on the freeze-bonding effect, which realizes the synergistic design from interface control, surface modification to low-temperature traveling wave processing, and provides technical support for atomic-level non-destructive processing of hard and brittle materials.

[0073] This invention discloses an atomic-level removal method and apparatus for hard and brittle materials based on the freeze-adhesion effect. First, the hard and brittle material sample undergoes surface pretreatment and termination state control. For non-hydrophilic materials, plasma treatment is used for hydrophilic modification. The sample is placed in a low-temperature experimental chamber, and the temperature of the sample stage and interface region is controlled via liquid nitrogen. A water medium is introduced between the sample surface and the cemented carbide loading head through a microfluidic channel inside the loading head, controlling the thickness of the interfacial water layer and the adhesion state of water molecules. Gradient cooling is used to form a quasi-liquid layer and a freeze-adhesion layer. Local removal experiments are conducted to determine the interface temperature, holding time, water layer thickness, and loading parameters. The determined process parameters are then imported into a low-temperature ultrasonic traveling wave field ultra-precision machining device. Ultrasonic traveling wave excitation is applied, driving the cemented carbide loading head to perform atomic-level removal of the microscopic protrusions on the sample surface under the guidance of the freeze-adhesion layer.

[0074] like Figure 1 As shown, an atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect is described, the method comprising the following steps:

[0075] S101: Surface cleaning and pretreatment of hard and brittle material samples. Specifically: Sample 1, made of hard and brittle material, undergoes multi-stage chemical cleaning and ultra-pure solvent treatment to remove contaminants from the sample surface.

[0076] S102: Based on the surface properties of hard and brittle materials, the termination state is controlled and hydrophilic modification is performed on the sample surface. Specifically, the termination state of sample 1 is controlled and hydrophilic modification is performed on the sample surface based on the surface properties of the hard and brittle materials. A sample of ultra-smooth silicon carbide hard and brittle materials with non-hydrophilic properties that has been atomically polished is selected as the modification substrate. Figure 2The microscopic effects of water molecules on the surface of silicon carbide in different termination states are shown. In this embodiment, the hydrogen termination layer 2, oxide layer 3, and hydroxylation layer 4 represent three representative termination states on the surface of the silicon carbide hard and brittle material sample 1, respectively. The number of hydrogen bonds 6 formed between water molecules 5 on the surface of the hydrogen termination layer 2 and the silicon carbide hard and brittle material sample 1 is the smallest; the number of hydrogen bonds 6 formed between water molecules 5 on the surface of the hydroxylation layer 4 and the silicon carbide hard and brittle material sample 1 is the largest.

[0077] Figure 3 This diagram illustrates the principle of hydrophilic modification of silicon carbide surfaces. In this embodiment, downstream plasma treatment is used to control the termination state and modify the hydrophilicity of the sample surface. Sample clamp 7 is used to hold sample 1, a hard and brittle silicon carbide material. Oxygen inlet 9, hydrogen inlet 10, and argon inlet 11 are used to introduce reaction gases into the device. High-energy ion bombardment zone 12 is used to excite the input gases. High-energy ion bombardment zone 12 and sample modification zone 8 are separated. Hydrogen and argon downstream plasma are used to construct a low-polarity hydrogen termination surface on the sample surface. Oxygen downstream plasma is used to introduce a controlled thin oxide layer and hydroxylation structure on the sample surface. The plasma treatment power is adjusted... Processing time Parameters such as these are used to control the hydrogen termination state coverage of the sample surface. for:

[0078]

[0079] in, For saturation coverage, The rate constant is related to the flow rate;

[0080] The oxide layer thickness on the sample surface Represented as:

[0081]

[0082] in, For adjustment coefficients, and The relevant processing power was determined experimentally. and processing time The exponential factor.

[0083] Hydroxyl site density on the sample surface Represented as:

[0084]

[0085] in, The number of hydroxyl sites on the sample surface. The surface area is the area of ​​action.

[0086] like Figure 4 As shown, in this embodiment, the change in hydrophilicity of the sample surface is characterized by static water contact angle measurement. The hard and brittle material sample 1 is placed horizontally on the contact angle measurement platform, and a predetermined volume of deionized water droplets is dropped onto the surface. After the droplet shape stabilizes, a side view image is acquired, and the static water contact angle formed between the droplet and the surface of the hard and brittle material sample 1 is measured.

[0087] S103: Place the hard and brittle material sample in the low-temperature experimental chamber and control the temperature interface area through liquid nitrogen cooling. Specifically: mount the hard and brittle material sample on the sample stage and control the temperature of the sample stage and interface area through the liquid nitrogen cooling path; set up a sealed structure in the low-temperature experimental chamber and adjust the temperature conditions in the interface area through closed-loop control.

[0088] S104: A water medium is introduced between the surface of the hard and brittle material sample and the loading head through a microchannel set inside the cemented carbide loading head; the amount of water medium introduced, the interface coverage range, and the thickness of the interface water layer are controlled; a gradient cooling method is used to make the interface region slowly cross the preset key temperature zone near the freezing point, forming a quasi-liquid layer and a frozen-bonded layer between the surface of the hard and brittle material sample and the loading head, and controlling the thickness, distribution state, and contact area of ​​the frozen-bonded layer.

[0089] The material of the cemented carbide loading head is selected and set according to the material type of the hard and brittle material sample. Figure 5 , 6 The schematic diagrams of the experimental apparatus for the localized removal of freezing adhesion of silicon and silicon carbide hard and brittle materials are shown respectively. In this embodiment, the sample stage 16 is located in the low-temperature experimental chamber 18, the microchannel 14 formed by the liquid nitrogen passage is built into the loading head, which is used to control the temperature of the interface area and cool it. The temperature detection unit 17 is used to detect the temperature of the interface area. The displacement mechanism 15 is used to drive the loading head to approach the sample 1 of hard and brittle material. The microchannel 14 is used to introduce water medium between the loading head and the sample 1 of hard and brittle material.

[0090] exist Figure 5 In this embodiment, a tungsten carbide loading head 13-1 is used in conjunction with a silicon hard and brittle material sample 1-1. Figure 6 In this embodiment, a tungsten-cobalt cemented carbide loading head 13-2 is used in conjunction with a silicon carbide hard and brittle material sample 1-2;

[0091] like Figure 7 As shown, in this embodiment, a water medium is introduced to spread a liquid water layer on the surface of the hard and brittle sample 1. When the interface temperature slowly crosses the vicinity of the freezing point, water molecules first form an adsorbed water layer on the surface, and then partially freeze to form an initial frozen layer. A quasi-liquid layer is retained on the sample surface, and a stable frozen layer is formed after further cooling.

[0092] S105: Conduct localized removal experiments within the liquid nitrogen temperature range, establish experimental conditions for low-temperature micro-area removal, and control the thickness, distribution, and contact area of ​​the frozen-bonded layer, as well as the uniformity parameters of the frozen-bonded layer thickness. Represented as:

[0093]

[0094] in, The average thickness of the frozen bond layer. This represents the standard deviation of the frozen bond layer thickness.

[0095] The loading direction is adjusted by a precision centering mechanism to make it consistent with the interface normal. The loading head applies a normal load to the sample surface to carry out local removal experiments.

[0096] S106: Adjust parameters such as interface temperature and holding time to characterize the interface adhesion work and surface lattice structure changes; measure the interface peeling force and calculate the interface adhesion work; conduct in-situ observation of the atomic structure of the surface of hard and brittle material samples to obtain the surface lattice constant and interatomic spacing distribution, and compare the lattice structure changes between the clean surface and the frozen-bonded interface state.

[0097] S107: Sample 1, made of hard and brittle material, is placed in a low-temperature ultrasonic traveling wave field ultra-precision machining device, and the process parameters are determined through a local removal experiment. The low-temperature ultrasonic traveling wave field ultra-precision machining device adopts a split configuration of bottom-conductive temperature control and top precision loading, including a medium supply nozzle 21, a temperature control base 22, a medium delivery pipe 23, a voice coil motor 24, a force sensor 25, a central negative pressure channel 26, an elastomer stator 29, vibration isolation pads 30, a connecting flange 31, a piezoelectric ceramic array 32, and a machining head housing 33, as shown below. Figure 8 , Figure 9 As shown:

[0098] In this embodiment, the ultrasonic traveling wave processing module 20 serves as the core execution component, including an elastomer stator 29, vibration isolation pads 30, a connecting flange 31, a piezoelectric ceramic array 32, and a processing head housing 33. The elastomer stator 29 is located at the bottom and is used to establish frictional contact with the frozen adhesive layer 28 on the surface of the workpiece 27.

[0099] In this embodiment, the relative motion and loading module is used to realize multi-degree-of-freedom spatial control and load application between the machining head and the workpiece. Normal loading is achieved by a voice coil motor 24 and a force sensor 25 arranged in series. The voice coil motor 24, as a precision electromagnetic actuator along the Z-axis, has its output connected to the ultrasonic traveling wave machining module 20 via the force sensor 25, forming a closed-loop force control unit. This unit applies a precise and controllable normal pressure F to the machining area to maintain a constant frictional coupling state between the elastomer stator and the frozen adhesive layer 28.

[0100] In this embodiment, the medium supply and temperature control module mainly provides a low temperature field through the temperature control base 22 below, so that the fluid medium solidifies in situ on the surface of the workpiece 27 to form a frozen layer 28. The fluid medium is transmitted through the medium delivery pipe 23 and sprayed to the processing area by the medium supply nozzles 21 symmetrically arranged around the processing head.

[0101] In this embodiment, the negative pressure flow field control and chip removal module uses a central negative pressure channel 26 at the top of the ultrasonic traveling wave field ultra-precision machining device to recover debris under negative pressure;

[0102] In this embodiment, the temperature control module in the medium supply and temperature control module adopts any of the following structural forms:

[0103] (1) Bottom conduction cooling type: includes a temperature-controlled stage with a refrigerant circulation channel or refrigeration device inside, and the workpiece 27 is fixed on the surface of the temperature-controlled stage; (2) Coaxial integrated jet type: includes a cryogenic fluid channel integrated inside the ultrasonic traveling wave processing module 20, which is used to directly output low-temperature fluid medium to the processing area.

[0104] In this embodiment, the XYZ coordinate system indicates the relative motion degrees of freedom between the modules, wherein the workpiece stage and the processing module can perform relative scanning motion along the XY plane; the ultrasonic traveling wave processing module 20 remains stationary in the horizontal direction, and the workpiece stage is driven to perform XY plane scanning by the drive mechanism connected to the bottom of the temperature control base; the workpiece stage remains stationary in the horizontal direction, and the entire processing head module is driven to perform XY plane scanning by the drive mechanism connected above the voice coil motor 24.

[0105] In this embodiment, the ultrasonic traveling wave processing module is configured according to the characteristics of the processing area as one of the following configurations: Rotating traveling wave type: The elastomer stator 29 has a ring or disk-shaped structure, and the piezoelectric ceramic array 32 is configured to excite traveling waves propagating tangentially in the circumferential direction of the elastomer stator to drive the frozen bonded layer 28 to generate rotational shear motion. Linear traveling wave type: The elastomer stator 29 has a rectangular beam or plate-shaped structure, and the piezoelectric ceramic array 32 is configured to excite traveling waves propagating axially in the length direction of the elastomer stator 29 to drive the frozen bonded layer 28 to generate translational shear motion.

[0106] like Figure 8 As shown, in this embodiment, the ultrasonic traveling wave processing module 20 exhibits a multi-layered coaxial nesting feature. The module has a central negative pressure channel 26 at its center, which extends upwards and connects to the top power loading mechanism. A connecting flange 31 is integrated into the outer wall of the central negative pressure channel 26 to bear the axial load from above.

[0107] In the power transmission link, the output force of the voice coil motor 24 is monitored in real time by the force sensor and acts on the processing head housing 33 through the connecting flange 31; the vibration isolation pad 30 is located between the connecting flange 31 and the processing head housing 33, and is made of an elastic material with high damping characteristics. It is designed to absorb the high-frequency ultrasonic vibration generated by the bottom piezoelectric ceramic array 32 and prevent mechanical vibration from being transmitted upward to the force sensor 25.

[0108] The core of the bottom of the processing module is the drive stator assembly, which includes an annular elastomer stator 29 and a piezoelectric ceramic array 32 bonded to the back of the stator through a coupling layer. The piezoelectric excitation unit is composed of a piezoelectric ceramic array 32 distributed according to a preset phase, which is used to drive the stator to generate ultrasonic traveling waves under alternating electric field excitation.

[0109] In terms of fluid transmission, the bottom port of the central negative pressure channel 26 is concave relative to the processing bottom surface of the elastomer stator 29, and a low-pressure zone is established in the center of the processing area. The outermost medium conveying pipe 23 transmits the fluid medium to the medium supply nozzle 21, and supplies the material evenly to the processing contact area through multi-point spraying.

[0110] S108: An ultrasonic traveling wave field is applied to excite and drive the cemented carbide loading head to perform atomic-level material removal on the surface of hard and brittle material samples under the guidance of a frozen-bonded layer. Figure 10 As shown, it includes the following steps:

[0111] S201: A fluid medium is supplied to the surface of the workpiece 27 to be processed and a low temperature field is applied, so that the fluid medium is rapidly solidified on the surface of the workpiece to form a freeze-adhesive layer 28.

[0112] S202: Control the ultrasonic traveling wave processing module 20 to press the frozen adhesive layer 28;

[0113] S203: Excite the elastomer stator 29 to generate ultrasonic traveling waves, drive the frozen adhesive layer 28 to move tangentially, and use the frozen adhesive layer 28 to remove the micro-protrusion structure on the surface of sample 1.

[0114] S204: Discharge the frozen adhesive layer 28 residue containing material debris from sample 1.

[0115] In this embodiment, before step 101, the wettability of the workpiece 27 to be processed is controlled and hydrophilicized to improve the spreading ability of the fluid medium on the workpiece surface. In steps 101 and 103, the supply rate of the fluid medium and the cooling power of the low temperature field are controlled to reach a dynamic balance, so that a new frozen layer 28 is continuously generated in front of the moving path of the sample 1 of the ultrasonic traveling wave processing module, while the frozen layer 28 is broken or melted after processing. During the processing, the negative pressure flow field control and chip removal module is used to establish a negative pressure field in the center of the processing area, guide the fluid medium located on the periphery to converge towards the center, and simultaneously suck away the low temperature solid debris after peeling to prevent the debris from being recast or remaining.

[0116] like Figure 11 The image shows the removal of the micro-interface. The frozen adhesive layer 28 forms an interface connection with the surface of sample 1 through hydrogen bonds 6, and a quasi-liquid layer 34 is retained between it and sample 1. Under the action of shear force, the frozen adhesive layer 28 causes the surface of sample 1 to be peeled off, and the removal depth is about 2 to 3 atomic layers.

[0117] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. An atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect, characterized in that, Includes the following steps: Step 1: Clean the surface of the hard and brittle material sample and pre-treat the sample surface; Step 2: Modify the surface of the sample by controlling the termination state and hydrophilicizing it according to the surface properties of the hard and brittle material sample; Step 3: Place the hard and brittle material sample into the low-temperature experimental chamber, and control the temperature of the sample stage and interface area through the liquid nitrogen cooling module; Step 4: Introduce an aqueous medium between the sample surface and the loading head through a microchannel set inside the loading head, control the thickness of the interfacial water layer and the adhesion state of water molecules, and form a quasi-liquid layer and a freeze-bonded layer. Step 5: Conduct localized removal experiments within the liquid nitrogen temperature range to control the thickness and distribution of the frozen layer; Step 6: Adjust the interface temperature and holding time parameters to characterize the interface adhesion and surface lattice structure changes; Step 7: Place the hard and brittle material sample in the low-temperature ultrasonic traveling wave field ultra-precision machining device and introduce the process parameters determined by the local removal experiment; Step 8: Apply ultrasonic traveling wave excitation to drive the cemented carbide loading head to perform atomic-level material removal on the sample surface under the guidance of the frozen adhesive layer.

2. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 1, characterized in that: In step 2, an ultra-smooth silicon carbide sample with non-hydrophilic properties that has undergone atomic-level polishing is selected as the modification substrate. Downstream plasma treatment was used to modulate the termination state and hydrophilicity of the sample surface; the plasma generation region and the sample reaction region were separated; a low-polarity hydrogen termination surface was constructed on the sample surface using hydrogen and argon downstream plasma; a controlled thin oxide layer and hydroxylation structure were introduced on the sample surface using oxygen downstream plasma; and the hydrogen termination state coverage of the sample surface was controlled by adjusting the plasma treatment power and treatment time.

3. The atomic-level removal method for hard and brittle materials based on the freeze-bonding effect as described in claim 1, characterized in that: Step 4 introduces a water medium between the sample surface and the loading head through a microchannel set inside the cemented carbide loading head; controls the amount of water medium introduced, the interface coverage range, and the thickness of the interface water layer; and achieves gradient cooling through a liquid nitrogen cooling module to form a quasi-liquid layer and a frozen adhesive layer between the sample surface and the loading head, controlling the thickness, distribution state, and contact area of ​​the frozen adhesive layer.

4. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 1 or 3, characterized in that: The material of the cemented carbide loading head is selected and set according to the material type of the hard and brittle material sample. When the sample is a silicon sample, the loading head is a tungsten carbide loading head; when the sample is a silicon carbide sample, the loading head is a tungsten-cobalt cemented carbide loading head.

5. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 1, characterized in that: The ultra-precision machining device for the low-temperature ultrasonic traveling wave field in step 7 includes a medium supply and temperature control module, an ultrasonic traveling wave machining module, a relative motion and loading module, and a negative pressure flow field control and chip removal module.

6. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 5, characterized in that, The ultrasonic traveling wave processing module includes an elastomer stator and a piezoelectric excitation unit, and is configured as either a rotating traveling wave or a linear traveling wave according to the characteristics of the processing area.

7. The atomic-level removal method for hard and brittle materials based on the freeze-bonding effect as described in claim 6, characterized in that: The elastomer stator is made of a high-quality metallic elastic material, and its working surface in contact with the frozen adhesive layer is provided with micro-nano friction-increasing textures; the piezoelectric excitation unit includes a piezoelectric ceramic array, which is bonded to the surface of the elastomer stator through a coupling layer; the piezoelectric ceramic array is arranged according to a preset wavelength and phase distribution, and is used to excite the elastomer stator to generate bending traveling waves under alternating electric field excitation.

8. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 5, characterized in that, The medium supply and temperature control module includes a temperature control unit and a medium supply unit. The temperature control unit adopts either a bottom conduction cooling type or a coaxial integrated spray type structure. The medium supply unit includes a precision fluid delivery pump and a fluid spray terminal, which are used to uniformly coat the fluid medium onto the workpiece surface in the form of droplets, jets or atomization.

9. The atomic-level removal method for hard and brittle materials based on the freeze-adhesion effect as described in claim 5, characterized in that: The negative pressure flow field control and chip removal module establishes a negative pressure field in the center of the processing area, guiding the fluid medium located on the periphery to converge towards the center, and simultaneously sucking away the solid debris after stripping.

10. The atomic-level removal method for hard and brittle materials based on the freeze-bonding effect as described in claim 1, characterized in that: The specific implementation steps of step 8 are as follows: Step 8-1: Supply water medium to the surface of the workpiece to be processed and apply a low temperature field to make the water medium solidify rapidly on the surface of the workpiece to form a freeze-adhesive layer; Step 8-2: Control the ultrasonic traveling wave processing module to press the frozen adhesive layer; Step 8-3: Excite the elastomer stator to generate ultrasonic traveling waves, drive the frozen adhesive layer to move tangentially, and use the frozen adhesive layer to remove the micro-protrusion structure on the surface of the workpiece; Step 8-4: Remove the frozen adhesive residue containing workpiece material debris.

Images