CN119098828A - Ultrasonic cavitation magnetorheological mechanical polishing device and GaN efficient polishing method - Google Patents
Ultrasonic cavitation magnetorheological mechanical polishing device and GaN efficient polishing method Download PDFInfo
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- CN119098828A CN119098828A CN202411348407.3A CN202411348407A CN119098828A CN 119098828 A CN119098828 A CN 119098828A CN 202411348407 A CN202411348407 A CN 202411348407A CN 119098828 A CN119098828 A CN 119098828A
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- 238000005498 polishing Methods 0.000 title claims abstract description 191
- 238000000034 method Methods 0.000 title claims abstract description 31
- 239000007788 liquid Substances 0.000 claims abstract description 56
- 239000000919 ceramic Substances 0.000 claims abstract description 11
- 239000000696 magnetic material Substances 0.000 claims abstract description 4
- 239000002245 particle Substances 0.000 claims description 30
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 13
- 239000006061 abrasive grain Substances 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 6
- 230000005855 radiation Effects 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 238000009423 ventilation Methods 0.000 claims description 4
- 239000003822 epoxy resin Substances 0.000 claims description 3
- 229920000647 polyepoxide Polymers 0.000 claims description 3
- 239000003381 stabilizer Substances 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 10
- 230000007547 defect Effects 0.000 abstract description 4
- 239000000126 substance Substances 0.000 description 23
- 239000000243 solution Substances 0.000 description 7
- 230000003746 surface roughness Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 6
- 239000011553 magnetic fluid Substances 0.000 description 6
- 238000007517 polishing process Methods 0.000 description 6
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 229910002604 Ga-H Inorganic materials 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- SZVJSHCCFOBDDC-UHFFFAOYSA-N ferrosoferric oxide Chemical compound O=[Fe]O[Fe]O[Fe]=O SZVJSHCCFOBDDC-UHFFFAOYSA-N 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
- B24B1/005—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes using a magnetic polishing agent
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
- B24B31/10—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor involving other means for tumbling of work
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
- B24B31/12—Accessories; Protective equipment or safety devices; Installations for exhaustion of dust or for sound absorption specially adapted for machines covered by group B24B31/00
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B31/00—Machines or devices designed for polishing or abrading surfaces on work by means of tumbling apparatus or other apparatus in which the work and/or the abrasive material is loose; Accessories therefor
- B24B31/12—Accessories; Protective equipment or safety devices; Installations for exhaustion of dust or for sound absorption specially adapted for machines covered by group B24B31/00
- B24B31/14—Abrading-bodies specially designed for tumbling apparatus, e.g. abrading-balls
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
- Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)
Abstract
The invention discloses an ultrasonic cavitation magneto-rheological mechanical polishing device which comprises an operation table, wherein a polishing groove is formed in the top of the operation table and used for containing magneto-rheological polishing liquid, a clamping driving mechanism is arranged in the polishing groove and used for clamping a workpiece to be polished and driving the workpiece to rotate, an ultrasonic transducer is arranged in the polishing groove and above the clamping driving mechanism, the ultrasonic transducer comprises a rear cover plate, a piezoelectric ceramic plate and a front cover plate which are sequentially arranged, the rear cover plate and the front cover plate are locked through pre-tightening bolts, the front cover plate is made of magnetic materials and faces the clamping driving mechanism, and the clamping driving mechanism and the ultrasonic transducer are respectively and electrically connected with a controller. Correspondingly, the invention also provides a GaN efficient polishing method, which uses the ultrasonic cavitation magneto-rheological mechanical polishing device to polish GaN, has high material removal efficiency, can avoid stress defects on the surface of the GaN, and has good polishing quality.
Description
Technical Field
The invention relates to the technical field of GaN polishing, in particular to an ultrasonic cavitation magneto-rheological mechanical polishing device and a GaN efficient polishing method.
Background
As the first generation of semiconductor materials reached their theoretical limit, researchers began to explore new semiconductor materials in order to improve the performance of semiconductor devices in high-voltage, high-temperature conditions. Among them, gaN has been sought after by virtue of its excellent mechanical, electrical, thermal, optical, etc. properties. With the continuous development of GaN devices, the requirements for the GaN devices are increasing, and in particular, in some applications in the field of ultra-precise processing, the surface precision of the GaN devices is required to reach the nanometer level. Therefore, the efficient atomic scale control of the GaN surface is a key to the large-scale popularization and application of the GaN surface.
The ultra-precise polishing technology is an effective way to obtain GaN nanoscale surfaces and nondestructive subsurface. For polishing of GaN, chemical mechanical polishing is a mature processing technology at present, and combines two methods of chemistry and machinery to remove uneven parts of the surface of a material so as to enable the surface to be highly flat. During polishing, the chemical reagent in the polishing liquid reacts chemically with the surface of the material to be polished to form a reaction product layer which is easy to abrade away and then is removed by the polishing pad. However, in the conventional chemical mechanical polishing, the abrasive grains are pressed against the workpiece under the action of the polishing pad to remove the raised portions on the surface of the material, and stresses and defects may be introduced during the polishing process, which affect the performance of the workpiece, and it is difficult to ensure uniform pressing force for each portion for a complex structure. In addition, the conventional chemical mechanical polishing liquid has too low viscosity to control the entire polishing area, so that the polishing efficiency is limited.
Disclosure of Invention
The application provides an ultrasonic cavitation magneto-rheological mechanical polishing device which is used for overcoming the problems in the prior art. The ultrasonic cavitation magneto-rheological mechanical polishing device adopts magneto-rheological polishing liquid to replace the traditional chemical mechanical polishing liquid, plays a role of a polishing pad, is used for carrying out high-frequency vibration in the polishing process to generate cavitation effect and drive abrasive particles in the polishing liquid to impact the surface of a workpiece to carry out chemical mechanical reaction so as to polish the workpiece, combines three technologies of ultrasonic cavitation, magneto-rheological polishing and chemical mechanical polishing, improves the polishing efficiency, reduces the mechanical damage of the workpiece during polishing, and is suitable for polishing the workpiece with a complex structure. Correspondingly, the application also provides a GaN efficient polishing method, the ultrasonic cavitation magneto-rheological mechanical polishing device is used for polishing GaN, the material removal efficiency is high, the stress defect on the surface of the GaN can be avoided, and the polishing quality is good.
For the polishing device, the technical scheme of the application is as follows:
The ultrasonic cavitation magneto-rheological mechanical polishing device comprises an operation table, wherein a polishing groove is formed in the top of the operation table and used for containing magneto-rheological polishing liquid, a clamping driving mechanism is arranged in the polishing groove and used for clamping a workpiece to be polished and driving the workpiece to rotate, an ultrasonic transducer is arranged in the polishing groove and above the clamping driving mechanism, the ultrasonic transducer comprises a rear cover plate, a piezoelectric ceramic plate and a front cover plate which are sequentially arranged, the rear cover plate and the front cover plate are locked through pre-tightening bolts, the front cover plate is made of magnetic materials and faces the clamping driving mechanism, and the clamping driving mechanism and the ultrasonic transducer are respectively and electrically connected with a controller.
Compared with the prior art, the ultrasonic cavitation magneto-rheological mechanical polishing device combines three technologies of ultrasonic cavitation, magneto-rheological polishing and chemical mechanical polishing, improves polishing efficiency, reduces mechanical damage of workpieces during polishing, and is suitable for polishing workpieces with complex structures. The method comprises the following steps:
(1) The magnetorheological polishing solution is adopted to replace the traditional chemical mechanical polishing solution, so that the effect of a polishing pad is achieved, and magnetic fluid can correct different shapes within a certain range, so that chemical mechanical polishing is not limited to plane polishing, flexible polishing of complex structures and micro-groove workpieces can be realized, and the application range is wide;
(2) By arranging the ultrasonic transducer, high-frequency vibration is continuously carried out in the polishing process so as to generate cavitation effect, normal force in the polishing process is provided, abrasive particles in the magnetorheological polishing liquid are driven to impact the surface of the workpiece so as to generate chemical mechanical reaction, and the polishing of the workpiece is realized, so that the stress defect generated by continuously extruding local bulges when the traditional polishing pad is used can be effectively avoided;
(3) When polishing a complex curved surface, magnetically sensitive particles in magnetorheological polishing liquid are close to the front cover plate due to the constraint of a magnetic field to generate magnetic buoyancy, nonmagnetic abrasive particles are close to the surface of a workpiece under the action of ultrasonic cavitation and chemically react with the workpiece in an OH-environment to generate chemical products which are easier to remove on the surface of the workpiece, and then an oxide layer is removed by using the abrasive, so that the material is easier to remove;
(4) The ultrasonic transducer continuously performs high-frequency vibration in the polishing process, the magnetic fluid is subjected to acceleration of gravity 10 times and is separated from the front cover plate, so that the phenomenon that the magnetic fluid is solidified at the front end of the front cover plate due to moisture evaporation in long-time use can be effectively avoided, the update of the magnetic fluid is convenient to realize, and the ultrasonic cavitation can decompose the water in the magnetorheological polishing liquid to generate more OH-, so that the chemical mechanical reaction is promoted, and the polishing efficiency is improved.
In the ultrasonic cavitation magneto-rheological mechanical polishing device, a polishing liquid conveying pipe is further arranged above the clamping driving mechanism, and the polishing liquid conveying pipe is connected with a polishing liquid supply system. At the moment, the magnetorheological polishing liquid is more convenient to fill, and environmental pollution caused by splashing of the magnetorheological polishing liquid in the filling process can be avoided.
In the ultrasonic cavitation magneto-rheological mechanical polishing device, the clamping driving mechanism comprises a vacuum chuck, a group of ventilation grooves are formed in the vacuum chuck along the circumferential direction, a rotating shaft connected with a driving motor is arranged at the bottom of the vacuum chuck, an extraction opening is further formed in the vacuum chuck, a rotary joint is arranged at the extraction opening, and the rotary joint is communicated with a vacuum pump through a vacuum pipeline. Compared with the method that the workpiece is directly pressed or extruded, the workpiece is fixed in a vacuum adsorption mode, so that the workpiece is not easy to damage, and the integrity and safety of the workpiece can be guaranteed to the greatest extent.
In the ultrasonic cavitation magneto-rheological mechanical polishing device, the ultrasonic transducer is clamped and fixed through the clamp, and the clamp is fixed at the bottom of the polishing groove. At this time, the structure is simple, the assembly is convenient, and the implementation is easy.
In the ultrasonic cavitation magneto-rheological mechanical polishing device, the radiation surface of the front cover plate is an arc-shaped surface, and the radius of curvature of the radiation surface is 75-85 mm. At this time, the axial sound pressure of the ultrasonic transducer in the magnetorheological polishing liquid is high overall.
As optimization, in the ultrasonic cavitation magneto-rheological mechanical polishing device, the piezoelectric ceramic plate is a PZT-4 annular piezoelectric ceramic plate, has stable piezoelectric property and low price, and is beneficial to controlling the manufacturing cost.
As optimization, in the ultrasonic cavitation magneto-rheological mechanical polishing device, the polishing liquid supply system and the controller are integrally arranged in the operation table, so that the occupied space is reduced.
For the polishing method, the technical scheme of the application is as follows:
The method for polishing GaN efficiently uses the ultrasonic cavitation magneto-rheological mechanical polishing device to polish GaN, and comprises the following specific steps:
S1, placing GaN to be processed on a vacuum chuck, starting a vacuum pump to adsorb the GaN, inputting magnetorheological polishing liquid into a polishing groove through a polishing liquid conveying pipe, wherein the magnetorheological polishing liquid comprises H 2O2 solution, magnetorheological liquid and abrasive particles, the magnetorheological liquid comprises water base, magnetosensitive particles and a stabilizer, the abrasive particles are alumina, S2, starting a driving motor to drive the vacuum chuck to rotate so as to drive the GaN to rotate, and simultaneously starting an ultrasonic transducer, wherein the magnetosensitive particles in the polishing liquid can generate magnetic buoyancy under the magnetic action of a front cover plate of the ultrasonic transducer, and the nonmagnetic alumina abrasive particles impact the GaN surface under the cavitation action of the ultrasonic transducer to generate chemical mechanical reaction to polish the GaN.
Compared with the prior art, the GaN high-efficiency polishing method combines three technologies of ultrasonic cavitation, magnetorheological polishing and chemical mechanical polishing to polish GaN, has high polishing efficiency and good quality, adopts the magnetorheological polishing liquid to replace the traditional magnetic fluid polishing hard polishing mode, selects aluminum oxide with lower hardness as abrasive particles at the same time, and drives the abrasive particles to contact with the GaN surface by virtue of the impact force generated by the ultrasonic cavitation effect, and chemically reacts with the GaN in an OH-environment to generate softer chemical products, so that the polished GaN surface cannot leave processing stress, has good polishing quality, and in addition, the ultrasonic cavitation can decompose moisture to generate more OH-, thereby promoting the progress of chemical mechanical reaction and improving the polishing efficiency.
In the optimized GaN efficient polishing method, the surface of the magnetosensitive particles is coated with epoxy resin, the concentration of H 2O2 is 20% -30%, the rotating speed of the vacuum chuck is 300 rpm in the step S2, and the alumina abrasive particles impact the GaN surface at the speed of 60 m/S.
Drawings
FIG. 1 is a schematic structural view of an ultrasonic cavitation magnetorheological mechanical polishing device of the present application;
FIG. 2 is a schematic diagram of the structure of an ultrasonic transducer in an embodiment of the application;
FIG. 3 is an equivalent circuit diagram of an ultrasonic transducer in an embodiment of the application;
FIG. 4 is a vibration pattern of an ultrasonic transducer in an embodiment of the application;
FIG. 5 is a schematic view of polishing performed by the polishing method of the present application;
FIG. 6 is a graph showing the relationship between polishing time and workpiece surface roughness when polishing is performed by the polishing method of the present application;
fig. 7 is a graph showing the comparison of the surface topography of a GaN workpiece polished by the conventional chemical mechanical polishing method and the polishing method of the present application.
The drawing comprises a 1-operating table, a 101-polishing groove, a 2-clamping driving mechanism, a 3-ultrasonic transducer, a 31-rear cover plate, a 32-piezoelectric ceramic plate, a 33-front cover plate, a 4-polishing liquid conveying pipe and a 5-clamp.
Detailed Description
The application is further illustrated by the following figures and examples, which are not intended to be limiting.
Examples (fig. 1-4):
Referring to fig. 1 and 2, the ultrasonic cavitation magneto-rheological mechanical polishing device in the embodiment comprises an operation table 1, a polishing groove 101 is formed in the top of the operation table 1 and used for containing magneto-rheological polishing liquid, a clamping driving mechanism 2 is arranged in the polishing groove 101 and used for clamping a workpiece to be polished and driving the workpiece to rotate, an ultrasonic transducer 3 is arranged in the polishing groove 101 and above the clamping driving mechanism 2, the ultrasonic transducer 3 comprises a rear cover plate 31, a piezoelectric ceramic plate 32 and a front cover plate 33 which are sequentially arranged, the rear cover plate 31 and the front cover plate 33 are locked through pre-tightening bolts, the front cover plate 33 is made of magnetic materials and faces the clamping driving mechanism 2, the clamping driving mechanism 2 and the ultrasonic transducer 3 are respectively and electrically connected with a controller, a polishing liquid conveying pipe 4 is further arranged above the clamping driving mechanism 2, and the polishing liquid conveying pipe 4 is connected with a polishing liquid supply system. Through setting up polish conveyer pipe 4 for it is more convenient when filling magnetorheological polishing liquid, avoided the magnetorheological polishing liquid to splash in the filling in-process moreover, cause the pollution of environment.
The ultrasonic cavitation magneto-rheological mechanical polishing device combines three technologies of ultrasonic cavitation, magneto-rheological polishing and chemical mechanical polishing, adopts magneto-rheological polishing liquid to play a role of a polishing pad, and generates cavitation effect by arranging an ultrasonic transducer to vibrate at high frequency in the polishing process so as to drive abrasive particles in the polishing liquid to impact the surface of a workpiece to perform chemical mechanical reaction, thereby realizing polishing of the workpiece with high polishing efficiency and good quality. In addition, the cavitation of the ultrasonic transducer 3 can decompose water to generate more OH-, so as to promote the chemical mechanical reaction and further improve the polishing efficiency.
In this embodiment, the clamping driving mechanism 2 includes an annular vacuum chuck, a set of ventilation grooves are circumferentially arranged on the vacuum chuck (a workpiece is placed above the ventilation grooves), a rotating shaft (integrally formed by the rotating shaft and the vacuum chuck) connected with a driving motor is arranged at the bottom of the vacuum chuck, an extraction opening is further arranged on the vacuum chuck, a rotary joint (a rotary joint with a bearing, an outer ring and a fixed inner ring rotate) is arranged at the extraction opening, and the rotary joint is communicated with a vacuum pump through a vacuum pipeline. Compared with the method that the workpiece is directly pressed or extruded, the workpiece is fixed in a vacuum adsorption mode, so that the workpiece is not easy to damage, and the integrity and safety of the workpiece can be guaranteed to the greatest extent. Further, the flatness of the vacuum chuck is controlled within 10 mu m, so that rotation deviation caused by machining errors is reduced, and the maximum rotating speed of the vacuum chuck is 800rpm.
In the embodiment, the ultrasonic transducer 3 is clamped and fixed by a clamp 5, and the clamp 5 is fixed at the bottom of the polishing groove 101. The ultrasonic transducer 3 adopts a longitudinal bending vibration multi-frequency transducer with the frequency of 23-41kHz, wherein a piezoelectric ceramic sheet 32 adopts a PZT-4 annular piezoelectric ceramic sheet with the thickness of 5mm, the inner diameter of 15mm and the outer diameter of 40mm, a rear cover plate 31 has the length of 18mm, M10 is selected to be 1.0-6H, the diameter of an internal thread round head is 10.4mm and the height is 10mm, a front cover plate 33 has the length of 21mm, the radiation surface is an arc-shaped surface, and the curvature radius of the radiation surface is 80mm (the front cover plate 33 is a rectangular thin plate with radian, and the front cover plate 33 is similar to the bending vibration of a thin plate during vibration). An equivalent circuit diagram of the entire ultrasonic transducer 3 is shown in fig. 3, and the vibration principle is shown in fig. 4. The applicant tests the processed ultrasonic transducer 3 through an impedance analyzer (new precision Co., ltd.) of model ZX70A-500K, and detects that the resonance frequencies of the ultrasonic transducer 3 are 24.565kHz, 33.205kHz and 35.815kHz, and the axial sound pressure of the ultrasonic transducer 3 in the magnetorheological polishing liquid at the frequency of 25.322kHz is high as a whole, and the sound pressure value at the position 1mm close to the surface of the front cover plate 33 is the highest, which is 5.3bar.
In this embodiment, the polishing solution supply system and the controller are integrally disposed in the console 1, which is beneficial to reducing the occupied space.
Implementation case:
The ultrasonic cavitation magneto-rheological mechanical polishing device is used for polishing GaN, and the method for efficiently polishing GaN comprises the following specific steps.
S1, placing GaN to be processed on a vacuum chuck, wherein the distance between the GaN to be processed and the bottom of an ultrasonic transducer 3 is 1mm, starting a vacuum pump to adsorb the GaN, inputting magnetorheological polishing liquid into a polishing groove 101 through a polishing liquid conveying pipe 4 (a polishing liquid supply system supplies polishing liquid containing OH-to a polishing area at the speed of 100mm 3/min) and immersing the GaN, wherein the magnetorheological polishing liquid comprises base liquid and abrasive particles, the abrasive particles are 1000-mesh aluminum oxide abrasive particles, the concentration is 30%, the base liquid is a mixed solution of H 2O 2 solution and magnetorheological liquid in a ratio of 1:4, the concentration of H 2O2 is 20%, the magnetorheological liquid comprises water base, magnetosensitive particles and a stabilizer, and the surface of the magnetosensitive particles is coated with epoxy resin (in the embodiment, the magnetosensitive particles are ferroferric oxide, and are easy to corrode in an acidic environment generated by hydrogen peroxide, so that the magnetosensitive particles are required to be coated and treated firstly to isolate the magnetosensitive particles from contacting with the acidic environment).
S2, starting a driving motor to drive a vacuum chuck to rotate so as to drive GaN to rotate, wherein the rotating speed is 300rpm, simultaneously starting an ultrasonic transducer 3, wherein at the moment, magnetically sensitive particles in magnetorheological polishing liquid can generate magnetic buoyancy under the magnetic action of a front cover plate 33 of the ultrasonic transducer, non-magnetic alumina abrasive particles impact the surface of GaN under the cavitation action of the ultrasonic transducer 3 (the impact speed is 60 m/S), the ultrasonic cavitation effect adds hydroxyl groups to Al atoms and Ga atoms under the OH-environment to form bond bridges Al-O-Ga-N, the bond bridges can be broken under the shearing stress action of magnetic fluid to form Al-O-Ga-OH and Al-O-Ga-H (see figure 5), the strength of the bond bridges is far lower than that of GaN, and the strength of alumina is lower than that of GaN, and is higher than that of mechanochemical products Al-O-Ga-OH and Al-O-Ga-H, so that during each polishing, the alumina only removes mechanochemical products (realizes polishing the surface of a workpiece) and cannot be damaged, and the surface of the workpiece has residual stress.
The influence of the polishing time on the surface roughness of the GaN workpiece is shown in fig. 6, the longer the polishing time is, the lower the surface roughness is, the trend of the reduction of the surface roughness tends to be gentle along with the increase of the polishing time, and in the embodiment, the surface roughness of the GaN workpiece reaches 1.047nm after the GaN with the initial roughness of 10nm is polished for 60min.
In order to verify that the polishing method of the present application has higher material removal efficiency and processing uniformity, the applicant polished GaN with an initial roughness of 10nm using a conventional chemical mechanical polishing method as a comparison.
The polishing method comprises the steps of polishing liquid comprising H 2O2 solution and 1000-mesh alumina abrasive grains, polishing under the conditions that the pressure is 12X 10 4 Pa, the rotation speed of a polishing disc is 100 r/min, the concentration of H 2O2 is 20%, and the concentration of the alumina abrasive grains is 30%, wherein the polishing principle is that the alumina abrasive grains chemically react with the GaN surface in a hydrogen peroxide environment to soften high-hardness GaN to generate reactants, and then the reactants are removed by the alumina abrasive grains under the pressure of a polishing pad to realize polishing.
Then, by white light interferometry, after polishing for 1h by the conventional chemical mechanical polishing method, gaN has a surface roughness of 1.166nm (see FIG. 7 a), while after polishing for 1h by the polishing method of the present application, gaN has a surface roughness of 1.047nm (see FIG. 7 b), and it can be seen that the polishing method of the present application has a better material removal rate, and furthermore, as can be seen from FIG. 7, the surface of the GaN workpiece polished by the chemical mechanical polishing method is a deeper scratch before residual polishing, while the surface uniformity of the GaN workpiece polished by the polishing method of the present application is higher, so that it can be demonstrated that the polishing method of the present application has higher efficiency and better quality when polishing the workpiece.
The above general description of the application and the description of specific embodiments thereof in relation to the present application should not be construed as limiting the scope of the application. Those skilled in the art can add, subtract or combine the features disclosed in the foregoing general description and/or the detailed description (including examples) to form other technical solutions within the scope of the application without departing from the disclosure of the application.
Claims (10)
1. The ultrasonic cavitation magneto-rheological mechanical polishing device is characterized by comprising an operation table (1), wherein a polishing groove (101) is formed in the top of the operation table (1) and is used for containing magneto-rheological polishing liquid, a clamping driving mechanism (2) is arranged in the polishing groove (101) and is used for clamping a workpiece to be polished and driving the workpiece to rotate, an ultrasonic transducer (3) is arranged in the polishing groove (101) and above the clamping driving mechanism (2), the ultrasonic transducer (3) comprises a rear cover plate (31), a piezoelectric ceramic plate (32) and a front cover plate (33) which are sequentially arranged, the rear cover plate (31) and the front cover plate (33) are locked through pre-tightening bolts, the front cover plate (33) is made of magnetic materials and faces the clamping driving mechanism (2), and the clamping driving mechanism (2) and the ultrasonic transducer (3) are electrically connected with a controller respectively.
2. The ultrasonic cavitation magneto-rheological mechanical polishing device according to claim 1 is characterized in that a polishing liquid conveying pipe (4) is further arranged above the clamping driving mechanism (2), and the polishing liquid conveying pipe (4) is connected with a polishing liquid supply system.
3. The ultrasonic cavitation magneto-rheological mechanical polishing device is characterized in that the clamping driving mechanism (2) comprises a vacuum chuck, a group of ventilation grooves are formed in the vacuum chuck along the circumferential direction, a rotating shaft connected with a driving motor is arranged at the bottom of the vacuum chuck, an air extraction opening is further formed in the vacuum chuck, a rotary joint is arranged at the air extraction opening, and the rotary joint is communicated with a vacuum pump through a vacuum pipeline.
4. The ultrasonic cavitation magneto-rheological mechanical polishing device according to claim 1, wherein the radiation surface of the front cover plate (33) is an arc surface, and the radius of curvature of the radiation surface is 75-85 mm.
5. The ultrasonic cavitation magneto-rheological mechanical polishing device according to claim 1, wherein the ultrasonic transducer (3) is clamped and fixed by a clamp (5), and the clamp (5) is fixed at the bottom of the polishing groove (101).
6. The ultrasonic cavitation magneto-rheological mechanical polishing device according to claim 1, wherein the piezoelectric ceramic plate (32) is a PZT-4 ring-shaped piezoelectric ceramic plate.
7. The ultrasonic cavitation magneto-rheological mechanical polishing device according to claim 2, wherein the polishing liquid supply system and the controller are integrally arranged in the operation table (1).
The method for efficiently polishing GaN is characterized by using the ultrasonic cavitation magneto-rheological mechanical polishing device of claim 3 to polish GaN, and comprises the following specific steps:
S1, placing GaN to be processed on a vacuum chuck, starting a vacuum pump to adsorb the GaN, and then inputting magnetorheological polishing liquid into a polishing groove (101) through a polishing liquid conveying pipe (4), wherein the magnetorheological polishing liquid comprises H 2O2 solution, magnetorheological liquid and abrasive particles, the magnetorheological liquid comprises water base, magnetosensitive particles and a stabilizer, and the abrasive particles are alumina;
S2, starting a driving motor to drive the vacuum chuck to rotate so as to drive GaN to rotate, and simultaneously starting an ultrasonic transducer (3), wherein at the moment, magnetically sensitive particles in the magnetorheological polishing liquid can generate magnetic force under the magnetic action of a front cover plate (33) of the ultrasonic transducer, and non-magnetic alumina abrasive particles impact the surface of the GaN under the cavitation action of the ultrasonic transducer (3) so as to realize the polishing of the GaN.
9. The GaN efficient polishing method of claim 8, wherein the surface of the magnetosensitive particles is coated with epoxy resin, and the concentration of H 2O2 is 20% -30%.
10. The method of high-efficiency polishing of GaN according to claim 8, wherein in said step S2, the rotation speed of the vacuum chuck is 300 rpm, and the alumina abrasive grains impact the GaN surface at a speed of 60 m/S.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411348407.3A CN119098828A (en) | 2024-09-26 | 2024-09-26 | Ultrasonic cavitation magnetorheological mechanical polishing device and GaN efficient polishing method |
Applications Claiming Priority (1)
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119526251A (en) * | 2024-12-12 | 2025-02-28 | 东营展宇制动系统有限责任公司 | A grinding device for brake production |
| CN119772668A (en) * | 2025-02-18 | 2025-04-08 | 揭阳市庆财五金塑胶有限公司 | Surface polishing method for hardware tableware |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN119526251A (en) * | 2024-12-12 | 2025-02-28 | 东营展宇制动系统有限责任公司 | A grinding device for brake production |
| CN119772668A (en) * | 2025-02-18 | 2025-04-08 | 揭阳市庆财五金塑胶有限公司 | Surface polishing method for hardware tableware |
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