Gallium nitride wafer chemical mechanical planarization device and process

Abstract

The invention provides a gallium nitride wafer chemical mechanical planarization device and process, and belongs to the technical field of wafer polishing, the gallium nitride wafer chemical mechanical planarization device comprises a front end unit, a transfer unit, a polishing unit and a drying unit which are sequentially distributed along a transfer path, the transfer unit is used for transferring the wafer among the front end unit, the polishing unit and the drying unit; the drying unit comprises a rolling cleaning module and a drying module, the rolling cleaning module comprises rolling cleaning parts located on the upper side and the lower side of the wafer, and the rolling cleaning parts are used for cleaning the upper surface and the lower surface of the wafer at the same time; and the drying module comprises a cleaning assembly and a drying assembly, the cleaning assembly is used for cleaning residual stains on the wafer, and the drying assembly is used for drying the wafer subjected to residual cleaning. The invention provides a gallium nitride wafer chemical mechanical planarization device and process, and aims to solve the problems that the existing gallium nitride wafer is not thoroughly cleaned and dried, the problems of uneven drying, water stain residue and the like are easily caused, and the surface quality of the wafer is influenced.

Description

Technical Field

[0001] The present invention belongs to the technical field of wafer polishing, and more specifically, relates to a chemical mechanical planarization device and process for gallium nitride wafers. Background Art

[0002] Chemical Mechanical Planarization (CMP) is a precision material processing technology that combines chemical etching and mechanical grinding. It is widely used in semiconductor manufacturing, optical devices, and precision machining. This technology forms a softened layer through a chemical reaction between the polishing slurry and the wafer surface. Abrasive particles on the polishing pad enable controlled material removal, thereby achieving high-precision surface planarization. However, due to the high hardness (Mohs hardness >9) and strong chemical inertness of gallium nitride (GaN), traditional CMP processes suffer from low material removal rates, severe surface damage, and low polishing efficiency. Furthermore, after CMP processing, residual polishing slurry, abrasive particles, and reaction products often remain on the wafer surface. If not thoroughly cleaned, this can affect the yield of subsequent processes.

[0003] Existing CMP equipment typically uses a multi-step cleaning and drying process. However, traditional cleaning methods (such as spray or ultrasonic cleaning) struggle to completely remove tiny particles and chemical residues from the wafer surface. GaN wafers, in particular, are susceptible to adsorption of hard abrasives (such as diamond particles) from the polishing slurry, increasing the risk of scratches. Furthermore, traditional drying methods (such as nitrogen purge or spin drying) can lead to uneven drying and residual water stains, compromising wafer surface quality. Therefore, an efficient, low-damage cleaning and drying solution is urgently needed to ensure the cleanliness and flatness of the GaN wafer surface after chemical mechanical planarization (CMP) while improving overall processing efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a chemical mechanical planarization device and process for gallium nitride wafers, aiming to solve the problem that the existing gallium nitride wafer cleaning and drying are not thorough, which easily leads to uneven drying, residual water stains and other problems, affecting the surface quality of the wafer.

[0005] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect, a chemical mechanical planarization apparatus for gallium nitride wafers is provided, comprising a front-end unit, a transfer unit, a polishing unit, and a drying unit sequentially distributed along a transfer path, wherein the transfer unit is used to transfer the wafer between the front-end unit, the polishing unit, and the drying unit; and the drying unit comprises: A rolling cleaning module, comprising rolling cleaning parts located on the upper and lower sides of the wafer, the rolling cleaning parts being used to clean the upper and lower surfaces of the wafer simultaneously; and The drying module comprises a cleaning component and a drying component. The cleaning component is used to clean the residual stains on the wafer, and the drying component is used to dry the wafer after the residual stains are cleaned.

[0006] In conjunction with the first aspect, in a possible implementation, the rolling cleaning module includes: A first drive assembly includes a first driver and a plurality of rollers connected to the first driver, wherein the plurality of rollers enclose a rotation space for accommodating a wafer, and the first driver is configured to drive the plurality of rollers to rotate about their own axes. The rollers drive the wafer to rotate about their own axes under the action of friction; a rolling cleaning assembly comprising a rolling driver and a rolling cleaning brush connected to the rolling driver, wherein the rolling cleaning brushes are respectively located on both sides of the wafer in the upper and lower directions, and the axis of the rolling cleaning brush is perpendicular to the axis of the roller, and the rolling driver is used to drive the rolling cleaning brush to rotate around its own axis to simultaneously clean the upper and lower surfaces of the wafer, and the rolling cleaning brushes form the rolling cleaning portion; and The first spray assembly includes a first storage box and a first spray pipe connected to the first storage box. The first spray pipe is used to spray the cleaning medium in the first storage box toward the wafer.

[0007] In combination with the first aspect, in a possible implementation, the drying unit further includes a deep cleaning module, and the deep cleaning module includes: A second drive assembly includes a second driver and a plurality of drive wheels connected to the second driver, wherein the plurality of drive wheels enclose a rotation space for accommodating the wafer, and the second driver is used to drive the plurality of drive wheels to rotate around their own axes. The drive wheels drive the wafer to rotate around their own axes under the action of friction; A rotary cleaning assembly comprising a rotary drive and a rotary cleaning brush connected to the rotary drive, wherein the rotary cleaning brush is located above the wafer, and the axis of the rotary cleaning brush is parallel to the axis of the driving wheel, and the rotary drive is used to drive the rotary cleaning brush to rotate around its own axis to simultaneously clean the upper surface of the wafer; and The second spray assembly includes a second storage box and a second spray pipe connected to the second storage box. The second spray pipe is used to spray the cleaning medium in the second storage box toward the wafer.

[0008] In combination with the first aspect, in a possible implementation, the polishing unit includes: A rotary robot arm comprising a rotary shaft and a plurality of rotary arms radially connected to the rotary shaft; and Multiple groups of polishing components are arranged in one-to-one correspondence with the multiple rotating arms. The polishing components include a polishing head connected to the rotating arm and a polishing disk arranged below the polishing head, and also include a guide pipe arranged on one side of the polishing disk.

[0009] In combination with the first aspect, in a possible implementation, the polishing unit further includes a loading platform, the rotary robot arm has the rotary arm corresponding to the loading platform, and the loading platform is used to carry the wafer.

[0010] In conjunction with the first aspect, in a possible implementation, the transfer unit includes: A first transmission component is provided at one side of the front-end unit, the first transmission component includes a first guide rail and a first manipulator slidably connected to the first guide rail, and the first manipulator is used to grab the wafer; a second transport assembly disposed between the front-end unit and the polishing unit, the second transport assembly comprising a second guide rail and a second robot slidably connected to the second guide rail, and further comprising a transfer tray disposed between the first transport assembly and the second transport assembly, the transfer tray being used to receive wafers transferred by the first robot or the second robot; and The third transmission component is arranged between the second transmission component and the polishing component. The third transmission component includes a first transmission platform, a second transmission platform and a third robot. The third robot grabs and transmits the wafer on the first transmission platform or the second transmission platform.

[0011] In combination with the first aspect, in a possible implementation, the polishing unit further includes a photocatalytic device disposed above the polishing disk, and the photocatalytic device is used to project ultraviolet rays toward the polishing disk.

[0012] In combination with the first aspect, in a possible implementation, an ultraviolet light projection lamp is provided in the polishing disc, and the ultraviolet light projection lamp is used to project ultraviolet light above the polishing disc.

[0013] In combination with the first aspect, in a possible implementation, an ultraviolet lamp is provided in the guide tube, and the ultraviolet lamp is used to maintain the reaction concentration of the polishing liquid.

[0014] The beneficial effects of the gallium nitride wafer chemical mechanical planarization device provided by the present invention are as follows: compared with the existing technology, the rolling cleaning parts located on the upper and lower sides of the wafer in the rolling cleaning module can clean the upper and lower surfaces of the wafer at the same time, which greatly improves the comprehensiveness and efficiency of cleaning compared to traditional spray or ultrasonic cleaning methods, and can effectively remove the polishing liquid, abrasive particles and reaction products remaining on the wafer surface, reducing the risk of subsequent process yield reduction due to incomplete cleaning. The cleaning component and the drying component in the drying module cooperate with each other, and the cleaning component further performs targeted cleaning on the residual stains on the wafer, avoiding the problem that traditional cleaning methods are difficult to remove tiny particles and chemical residues, effectively reducing the hard abrasives adsorbed on the surface of the gallium nitride wafer, and reducing the risk of scratches. The drying component realizes uniform drying of the wafer, solving the problems of uneven drying and water stains in traditional drying methods, thereby ensuring the cleanliness and flatness of the wafer surface after gallium nitride chemical mechanical planarization. The various units of the device work together to significantly improve overall processing efficiency by optimizing the cleaning and drying processes, providing an efficient and low-damage solution for the processing of gallium nitride materials in fields such as semiconductor manufacturing, optical devices and precision machining.

[0015] In a second aspect, an embodiment of the present invention further provides a gallium nitride wafer chemical mechanical planarization process, comprising: S100, placing the wafer to be cleaned into a wafer box; S200, the transfer unit transfers the wafers in the wafer box to the polishing unit, and the polishing unit sequentially performs rough polishing, intermediate polishing, and fine polishing on the wafers, wherein the material removal rate of the rough polishing is 3-6 μm / h, and the surface roughness Ra of the wafer after the rough polishing is completed is less than 1 nm; the material removal rate of the intermediate polishing is 1-1.5 μm / h, and the surface roughness Ra of the wafer after the rough polishing is completed is less than 0.7 nm; the material removal rate of the fine polishing is 0.5-0.7 μm / h, and the surface roughness Ra of the wafer after the rough polishing is completed is less than 0.5 nm; S300 , transferring the polished wafer to a drying unit, wherein the drying unit first cleans the residual dirt on the surface of the wafer and then dries the wafer.

[0016] The chemical mechanical planarization process for gallium nitride wafers provided by the present invention has the following beneficial effects: compared with the existing technology, in the polishing stage, the wafer is precisely transported to the polishing unit via a transfer unit, and rough polishing, intermediate polishing, and fine polishing are carried out in sequence. The material removal rate and surface roughness standards are set specifically for each stage. Rough polishing quickly removes a large amount of material at a rate of 3-6 μm / h and achieves a surface roughness Ra <1 nm. Intermediate polishing and fine polishing are gradually refined, further reducing the surface roughness to Ra <0.7 nm and Ra <0.5 nm, respectively. This step-by-step polishing method ensures that the wafer achieves extremely high surface flatness and precision, overcoming the problems of low processing efficiency and severe surface damage of traditional CMP processes for gallium nitride materials. In the cleaning and drying stage, the polished wafer is transferred to the drying unit, where residual stains are first thoroughly cleaned to effectively remove polishing liquid, abrasive particles, and reaction products, reducing the risk of scratches caused by adsorption of hard abrasives on the surface. Drying treatment then avoids problems such as uneven drying and residual water stains, thereby ensuring the cleanliness and flatness of the wafer surface. The various steps of this process are closely connected and coordinated, which significantly improves the processing quality and overall production efficiency of gallium nitride wafers, and provides a reliable technical solution for the processing of high-quality gallium nitride materials in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A top view of a gallium nitride wafer chemical mechanical planarization apparatus provided by an embodiment of the present invention; Figure 2 This is a schematic structural diagram of a rolling cleaning module used in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a deep cleaning module used in an embodiment of the present invention; Figure 4 A schematic structural diagram of a polishing assembly used in an embodiment of the present invention; Figure 5 This is a schematic structural diagram of the flow guide tube used in an embodiment of the present invention.

[0019] In the figure: 1. Front end unit; 2. Transfer unit; 201. First transfer assembly; 2011. First guide rail; 2012. First manipulator; 202. Second transfer assembly; 2021. Second guide rail; 2022. Second manipulator; 2023. Transfer tray; 203. Third transfer assembly; 2031. Third manipulator; 2032. First transfer platform; 2033. Second transfer platform; 3. Polishing unit; 301. Rotating manipulator; 3011. Rotating axis; 3012. Rotating arm; 30 2. Polishing assembly; 3021. Polishing disc; 3022. Guide tube; 3023. Polishing head; 303. Load platform; 304. Dresser; 305. Photocatalytic device; 306. UV lamp; 4. Drying unit; 401. Rolling cleaning module; 4011. Roller; 4012. Rolling cleaning brush; 4013. First spray pipe; 402. Deep cleaning module; 4021. Rotating cleaning brush; 4022. Drive wheel; 4023. Second spray pipe; 403. Drying module; 5. Wafer. DETAILED DESCRIPTION In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly limited, the terms "first", "second" or "third" are used to distinguish different objects, rather than to describe a specific order. Unless otherwise specified, other directional words, such as "vertical", "clockwise", "counterclockwise" and the like, indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the specific scope of protection of the present invention. In the claims, specification and the above-mentioned drawings of the present invention, unless otherwise expressly limited, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without a displacement relationship or relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements. In the claims, specification and the above-mentioned drawings of the present invention, the terms "including", "having" and their variations are intended to mean "including but not limited to".

[0021] Please also refer to Figures 1 to 5The gallium nitride wafer chemical mechanical planarization device and process provided by the present invention are now described. The gallium nitride wafer chemical mechanical planarization device includes a front-end unit 1, a transfer unit 2, a polishing unit 3, and a drying unit 4, which are sequentially arranged along a transfer path. The transfer unit 2 is used to transfer wafers 5 between the front-end unit 1, the polishing unit 3, and the drying unit 4. The drying unit 4 includes a rolling cleaning module 401 and a drying module 403. The rolling cleaning module 401 includes rolling cleaning sections located on the upper and lower sides of the wafer 5, and the rolling cleaning sections are used to simultaneously clean the upper and lower surfaces of the wafer 5. The drying module 403 includes a cleaning component and a drying component. The cleaning component is used to clean residual stains on the wafer 5, and the drying component is used to dry the wafer 5 after the residual stains have been cleaned.

[0022] Compared to the prior art, the gallium nitride wafer chemical mechanical planarization device provided by the present invention features rolling cleaning sections located on the upper and lower sides of wafer 5 within rolling cleaning module 401, capable of simultaneously cleaning the upper and lower surfaces of wafer 5. This significantly improves the comprehensiveness and efficiency of cleaning compared to traditional spray or ultrasonic cleaning methods, effectively removing residual polishing fluid, abrasive particles, and reaction products from the surface of wafer 5, and reducing the risk of subsequent process yield reduction due to incomplete cleaning. The cleaning and drying components within drying module 403 cooperate with each other, with the cleaning component further specifically cleaning residual contaminants on wafer 5, avoiding the difficulty of removing tiny particles and chemical residues encountered by traditional cleaning methods. This effectively reduces the amount of hard abrasive adsorbed on the surface of gallium nitride wafer 5 and reduces the risk of scratches. The drying component achieves uniform drying of wafer 5, resolving the problems of uneven drying and residual water stains associated with traditional drying methods, thereby ensuring the surface cleanliness and flatness of wafer 5 after gallium nitride chemical mechanical planarization. The various units of the device work together to significantly improve overall processing efficiency by optimizing the cleaning and drying processes, providing an efficient and low-damage solution for the processing of gallium nitride materials in fields such as semiconductor manufacturing, optical devices and precision machining.

[0023] In some embodiments, see Figure 2The rolling cleaning module 401 includes a first driving component, a rolling cleaning component and a first spraying component. The first driving component includes a first driver and a plurality of rollers 4011 connected to the first driver. The plurality of rollers 4011 enclose a rotating space for accommodating the wafer 5. The first driver is used to drive the plurality of rollers 4011 to rotate around their own axes. The rollers 4011 drive the wafer 5 to rotate around their own axes under the action of friction; the rolling cleaning component includes a rolling driver and a rolling cleaning brush 4012 connected to the rolling driver. The rolling cleaning brush 4012 is located on both sides of the wafer 5 in the upper and lower directions, and the axis of the rolling cleaning brush 4012 is perpendicular to the axis of the roller 4011. The rolling driver is used to drive the rolling cleaning brush 4012 to rotate around its own axis to simultaneously clean the upper and lower surfaces of the wafer 5. The rolling cleaning brush 4012 forms a rolling cleaning portion; the first spraying component includes a first storage box and a first spray pipe 4013 connected to the first storage box. The first spray pipe 4013 is used to spray the cleaning medium in the first storage box onto the wafer 5.

[0024] In this embodiment, the first drive assembly, through a first driver, rotates multiple rollers 4011. Rollers 4011 apply friction to the outer surface of wafer 5, causing wafer 5 to rotate about its own axis. This frictional force allows wafer 5 to be fully exposed during the cleaning process, significantly increasing the contact area and frequency between the surface of wafer 5 and the cleaning medium compared to traditional fixed-position cleaning methods. In the rolling cleaning assembly, a rolling driver drives rolling cleaning brushes 4012 located on the upper and lower sides of wafer 5 to rotate about their own axes. The axes are perpendicular to the axes of rollers 4011, increasing the contact area between rolling cleaning brushes 4012 and wafer 5. Combined with the rotation of wafer 5, this effectively removes stubborn polishing liquid residue, abrasive particles, and reaction products, significantly improving cleaning efficiency and quality. The first spray assembly evenly sprays the cleaning medium from the first storage tank onto the surface of wafer 5 through a first spray pipe 4013, continuously providing sufficient cleaning fluid for the cleaning process, further enhancing the cleaning effect and diluting stubborn stains, making them easier for rolling cleaning brushes 4012 to remove.

[0025] In some embodiments, see Figure 3The drying unit 4 also includes a deep cleaning module 402, which includes a second driving assembly, a rotating cleaning assembly and a second spray assembly. The second driving assembly includes a second driver and a plurality of driving wheels 4022 connected to the second driver. The plurality of driving wheels 4022 enclose a rotating space for accommodating the wafer 5. The second driver is used to drive the plurality of driving wheels 4022 to rotate around their own axes. The driving wheels 4022 drive the wafer 5 to rotate around its own axis under the action of friction; the rotating cleaning assembly includes a rotating driver and a rotating cleaning brush 4021 connected to the rotating driver. The rotating cleaning brush 4021 is located above the wafer 5, and the axis of the rotating cleaning brush 4021 is parallel to the axis of the driving wheel 4022. The rotating driver is used to drive the rotating cleaning brush 4021 to rotate around its own axis to clean the upper surface of the wafer 5 at the same time; the second spray assembly includes a second storage box and a second spray pipe 4023 connected to the second storage box. The second spray pipe 4023 is used to spray the cleaning medium in the second storage box onto the wafer 5. The second drive assembly rotates the multiple drive wheels 4022 via a second driver. Driven by friction, the wafer 5 continuously rotates around its own axis, expanding the cleaning coverage and ensuring that there are no blind spots on the surface of the wafer 5. In the rotary cleaning assembly, the rotating cleaning brush 4021, whose axis is parallel to the drive wheel 4022, is driven by the rotary driver to accurately and targetedly scrub the upper surface of the wafer 5, thoroughly removing stubborn chemical residues, tiny abrasive particles, and other impurities. It has a particularly strong stripping ability for hard particles that are easily adsorbed on the surface of the gallium nitride wafer 5. The second spray assembly evenly sprays the cleaning medium in the second storage tank onto the wafer 5 via the second spray pipe 4023. This not only dilutes the stains in a timely manner and reduces their adhesion strength, but also provides the necessary lubrication and flushing force for the cleaning process. Combined with the high-frequency scrubbing of the rotating cleaning brush 4021, it significantly improves cleaning efficiency and cleaning results.

[0026] Optionally, the rotating cleaning brush 4021 moves radially along the wafer 5 while rotating, so as to thoroughly clean the surface of the wafer 5.

[0027] It should be noted that the end of the rotating cleaning brush 4021 cleans the surface of the wafer 5, i.e., adopts a surface contact method. The circumference of the rolling cleaning brush 4012 cleans the surface of the wafer 5, using a line contact method. Of course, the end of the rotating cleaning brush 4021 can also form a tip, i.e., adopt a point contact method.

[0028] In some embodiments, see Figure 1The polishing unit 3 includes a rotating robotic arm 301 and multiple sets of polishing components 302. The rotating robotic arm 301 includes a rotating shaft 3011 and multiple rotating arms 3012 radially connected to the rotating shaft 3011; the multiple sets of polishing components 302 are arranged in a one-to-one correspondence with the multiple rotating arms 3012. The polishing component 302 includes a polishing head 3023 connected to the rotating arm 3012 and a polishing disk 3021 arranged below the polishing head 3023, and also includes a guide pipe 3022 arranged on one side of the polishing disk 3021.

[0029] The rotating robotic arm 301, through the combination of a rotating axis 3011 and radial rotating arms 3012, achieves the synchronized rotation of multiple polishing assemblies 302, significantly improving the efficiency of wafer 5 polishing. Compared to traditional single-piece polishing equipment, more wafers 5 can be processed in the same timeframe, effectively shortening production cycles. Of course, as needed, multiple polishing assemblies 302 can be used to perform multiple polishing operations on the same wafer 5, achieving high-precision surface planarization and effectively addressing the low material removal rates and severe surface damage associated with traditional CMP processes. The provision of the flow conduit 3022 precisely delivers the polishing liquid to the contact area between the polishing plate 3021 and the wafer 5. This not only ensures uniform distribution of the polishing liquid and improves chemical reaction consistency, but also allows for timely replenishment of polishing liquid consumed during the polishing process, preventing degradation of polishing quality due to insufficient polishing liquid, thereby reducing material waste and production costs.

[0030] Optionally, the polishing assembly 302 further includes a dresser 304 disposed on one side of the polishing disc 3021 , and the dresser 304 is used to dress the polishing pad of the polishing disc 3021 .

[0031] In some embodiments, see Figure 1 The polishing unit 3 further includes a loading platform 303 . The rotary robot arm 301 has a rotating arm 3012 corresponding to the loading platform 303 . The loading platform 303 is used to carry the wafer 5 . Transfer unit 2 transfers wafer 5 to loading platform 303. Rotating robotic arm 301 picks up wafer 5 and transfers it to a designated polishing plate 3021. Driven by a motor, the polishing pad of polishing plate 3021 and gallium nitride wafer 5 move relative to each other. Polishing head 3023 applies pressure to the surface of the polishing pad. A flow tube 3022 sprays polishing fluid onto the polishing pad, ensuring that the space between the polishing pad and gallium nitride wafer 5 is immersed in the polishing fluid during polishing. The combined effects of chemical oxidation and mechanical abrasive removal achieve efficient polishing of the wafer. After polishing is complete, polishing head 3023 rotates above loading platform 303 and removes gallium nitride wafer 5, which is then transferred to drying unit 4 via transfer unit 2. Loading platform 303 provides a stable and precise support platform for wafer 5, effectively preventing displacement or shaking of wafer 5 due to uneven force during polishing. This significantly enhances the stability of the polishing operation and ensures consistent polishing quality.

[0032] In some embodiments, see Figure 1 The transfer unit 2 includes a first transmission component 201, a second transmission component 202 and a third transmission component 203. The first transmission component 201 is correspondingly arranged on one side of the front end unit 1. The first transmission component 201 includes a first guide rail 2011 and a first manipulator 2012 slidably connected to the first guide rail 2011. The first manipulator 2012 is used to grab the wafer 5; the second transmission component 202 is arranged between the front end unit 1 and the polishing unit 3. The second transmission component 202 includes a second guide rail 2021 and a second manipulator 2012 slidably connected to the second guide rail 2021. 022, also includes a transfer tray 2023 arranged between the first transmission component 201 and the second transmission component 202, the transfer tray 2023 is used to receive the wafer 5 transferred by the first robot 2012 or the second robot 2022; the third transmission component 203 is arranged between the second transmission component 202 and the polishing component 302, the third transmission component 203 includes a first transmission platform 2032, a second transmission platform 2033 and a third robot 2031, the third robot 2031 grabs and transmits the wafer 5 on the first transmission platform 2032 or the second transmission platform 2033.

[0033] The first robot 2012 grabs the wafer 5 in the front-end unit 1 and slides along the first guide rail 2011, placing the wafer 5 on the transfer tray 2023. The second robot 2022 grabs the wafer 5 on the transfer tray 2023 and slides along the second guide rail 2021, placing the wafer 5 on the first transfer table 2032. The third robot 2031 grabs the wafer 5 on the first transfer table 2032 and transfers it to the polishing unit 3. After the wafer 5 is polished, the third robot 2031 grabs the wafer 5 and places it on the second transfer table 2033. The second robot 2022 grabs the wafer 5 on the second transfer table 2033 and flips it over. The second robot 2022 transfers the wafer 5 to the drying unit 4. The first manipulator 2012 of the first transmission component 201 cooperates with the first guide rail 2011 to quickly and accurately grab the wafer 5 from the front-end unit 1, and place it stably on the transfer plate 2023 along a predetermined path, ensuring the safety and accuracy of the wafer 5 in the initial transfer stage; the second manipulator 2022 and the second guide rail 2021 of the second transmission component 202 work in relay mode, and cooperate with the transfer plate 2023 to realize the transition transfer of the wafer 5 between the front-end unit 1 and the polishing unit 3. The transfer plate 2023 serves as an intermediate receiving platform, which effectively buffers the connection error between different transmission components and avoids collision or deviation of the wafer 5 due to frequent switching of transmission paths; the third manipulator 2031 of the third transmission component 203 cooperates with the first and second transmission platforms 2033, not only smoothly transferring the wafer 5 to the polishing unit 3, but also after the polishing of the wafer 5 is completed, through the flipping operation of the second manipulator 2022, accurately delivering the wafer 5 to the drying unit 4, ensuring the orderly flow of the wafer 5 between each processing step. This phased, multi-component coordinated transport mode significantly reduces time loss and human intervention during the transport of wafer 5, effectively avoiding damage to the surface of wafer 5 due to improper transport. At the same time, it improves the automation level and production efficiency of the entire gallium nitride wafer chemical mechanical planarization device, providing a solid transport foundation for ensuring the processing quality and yield of wafer 5.

[0034] Optionally, the first track and the second track may be parallel or perpendicular, or may be at any angle, which may be determined according to the actual positional relationship.

[0035] In some embodiments, see Figure 4 The polishing unit 3 further includes a photocatalytic device 305 disposed above the polishing disc 3021 , and the photocatalytic device 305 is used to project ultraviolet rays toward the polishing disc 3021 . By projecting ultraviolet light onto the polishing plate 3021 to maintain the OH⁻ concentration generated during the polishing slurry's outflow, this technology brings significant technological innovation and practical value to the polishing process of gallium nitride wafers 5. A stable and optimal OH⁻ concentration continuously intensifies the chemical reaction between the polishing slurry and the wafer 5 surface, accelerating the formation of a softened layer on the material surface and effectively improving material removal efficiency. This overcomes the low efficiency of traditional CMP processes for high-hardness, chemically inert materials like gallium nitride. A consistently stable OH⁻ concentration ensures consistent chemical reactions during polishing, enabling uniform material removal across the wafer 5 surface. This improves surface planarization accuracy, reduces surface roughness, and avoids surface damage caused by intense localized reactions. The photocatalytic device 305 precisely regulates the OH⁻ concentration, minimizing side reactions caused by unstable chemical reactions during polishing and reducing the generation of impurities in the polishing slurry. This not only extends the slurry's lifespan but also reduces the difficulty and stress of subsequent cleaning processes, ensuring fewer impurities remain on the wafer 5 surface, paving the way for subsequent drying and cleaning processes.

[0036] In some embodiments, a UV light projector is provided inside the polishing disc 3021 , and the UV light projector is used to project ultraviolet light onto the top of the polishing disc 3021 . During the polishing process, traditional methods have difficulty maintaining a consistent OH⁻ concentration, which can easily lead to a decrease in chemical reaction efficiency. However, this UV light projector, through continuous irradiation, stimulates the relevant components in the polishing liquid in real time, ensuring that the OH⁻ concentration remains at a stable and efficient level throughout the entire contact phase between wafer 5 and the polishing liquid. This strengthens the polishing liquid's corrosive and softening effects on the surface of gallium nitride wafer 5 and improves material removal efficiency. A stable OH⁻ concentration allows chemical reactions on the surface of wafer 5 to proceed evenly, avoiding local reactions that are too strong or too weak due to concentration fluctuations. This effectively prevents defects such as pits and scratches on the surface of wafer 5, significantly improving the accuracy and quality of surface flattening. In addition, maintaining a stable OH⁻ concentration reduces complex side reactions caused by concentration changes, reduces the generation of impurities in the polishing liquid, and prevents impurities from remaining on the surface of wafer 5. This not only reduces the pressure on subsequent cleaning processes, but also extends the life cycle of the polishing liquid, reducing production costs.

[0037] In some embodiments, see Figure 5 An ultraviolet lamp 306 is provided in the guide tube 3022, and the ultraviolet lamp 306 is used to maintain the reaction concentration of the polishing liquid. During the polishing slurry delivery phase, UV lamp 306 stimulates the relevant components in the polishing slurry, prompting the early generation of OH⁻. Compared to conventional processes, this allows the polishing slurry to possess greater chemical reactivity before contacting wafer 5. When the polishing slurry reaches polishing plate 3021 and contacts wafer 5, it rapidly reacts with the gallium nitride surface, accelerating the formation of a softened layer on the material surface, significantly increasing the material removal rate, effectively shortening polishing time, and improving production efficiency. A consistently stable OH⁻ concentration ensures consistent and uniform chemical reactions during the polishing process, avoiding localized excessive corrosion or insufficient reaction on the wafer 5 surface caused by fluctuations in reaction concentration. This effectively prevents surface defects such as scratches and pits, significantly improving the accuracy and quality of the wafer 5 surface planarization. Furthermore, a stable reaction concentration reduces unnecessary side reactions and impurity generation during the polishing process. This not only extends the lifespan of the polishing slurry, reduces the frequency of slurry replacement, and lowers production costs, but also reduces impurity residue on the wafer 5 surface, making subsequent cleaning easier and providing a better foundation for subsequent processes such as drying.

[0038] Based on the same inventive concept, the present invention also provides a gallium nitride wafer chemical mechanical planarization process. The gallium nitride wafer chemical mechanical planarization process includes: S100, placing the wafer 5 to be cleaned into a wafer 5 box; S200, the transfer unit 2 transfers the wafer 5 in the wafer 5 box to the polishing unit 3, and the polishing unit 3 performs rough polishing, intermediate polishing and fine polishing on the wafer 5 in sequence, wherein the material removal rate of the rough polishing is 3-6 μm / h, and the surface roughness Ra of the wafer 5 after the rough polishing is completed is less than 1 nm; the material removal rate of the intermediate polishing is 1-1.5 μm / h, and the surface roughness Ra of the wafer 5 after the intermediate polishing is completed is less than 0.7 nm; the material removal rate of the fine polishing is 0.5~0.7 μm / h, and the surface roughness Ra of the wafer 5 after the fine polishing is completed is less than 0.5 nm; S300 , transferring the polished wafer 5 to the drying unit 4 , where the drying unit 4 first cleans the dirt remaining on the surface of the wafer 5 and then dries the wafer 5 .

[0039] The chemical mechanical planarization process for gallium nitride wafers provided by the present invention has the following beneficial effects: compared with the prior art, in the polishing stage, the wafer 5 is precisely delivered to the polishing unit 3 via the transfer unit 2, and rough polishing, intermediate polishing, and fine polishing are carried out in sequence. The material removal rate and surface roughness standards are set specifically for each stage. The rough polishing quickly removes a large amount of material at a rate of 3-6 μm / h and achieves a surface roughness Ra <1 nm. The intermediate polishing and fine polishing are gradually refined, further reducing the surface roughness to Ra <0.7 nm and Ra <0.5 nm, respectively. This stepped polishing method ensures that the wafer 5 achieves extremely high surface flatness and precision, overcoming the problems of low processing efficiency and severe surface damage of traditional CMP processes for gallium nitride materials. In the cleaning and drying stage, the polished wafer 5 is transferred to the drying unit 4, where residual stains are first thoroughly cleaned to effectively remove polishing liquid, abrasive particles, and reaction products, reducing the risk of scratches caused by adsorption of hard abrasives on the surface. Drying is then performed to avoid problems such as uneven drying and residual water stains, thereby ensuring the cleanliness and flatness of the surface of the wafer 5. The various steps of this process are closely connected and coordinated, which significantly improves the processing quality and overall production efficiency of the gallium nitride wafer 5, and provides a reliable technical solution for the processing of high-quality gallium nitride materials in related fields.

[0040] Optionally, diamond is used as the abrasive for rough polishing, aluminum oxide sheets are used as the abrasive for medium polishing, and silicon dioxide is used as the abrasive for fine polishing to achieve host repair of gallium nitride wafers.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A chemical mechanical planarization device for gallium nitride wafers, characterized in that: The invention comprises a front-end unit, a transfer unit, a polishing unit and a drying unit sequentially distributed along a transfer path, wherein the transfer unit is used to transfer wafers between the front-end unit, the polishing unit and the drying unit; the drying unit comprises: A rolling cleaning module, comprising rolling cleaning parts located on the upper and lower sides of the wafer, the rolling cleaning parts being used to clean the upper and lower surfaces of the wafer simultaneously; and The drying module comprises a cleaning component and a drying component. The cleaning component is used to clean the residual stains on the wafer, and the drying component is used to dry the wafer after the residual stains are cleaned.

2. The gallium nitride wafer chemical mechanical planarization device according to claim 1, wherein: The rolling cleaning module includes: A first drive assembly includes a first driver and a plurality of rollers connected to the first driver, wherein the plurality of rollers enclose a rotation space for accommodating a wafer, and the first driver is configured to drive the plurality of rollers to rotate about their own axes. The rollers drive the wafer to rotate about their own axes under the action of friction; a rolling cleaning assembly comprising a rolling driver and a rolling cleaning brush connected to the rolling driver, wherein the rolling cleaning brushes are respectively located on both sides of the wafer in the upper and lower directions, and the axis of the rolling cleaning brush is perpendicular to the axis of the roller, and the rolling driver is used to drive the rolling cleaning brush to rotate around its own axis to simultaneously clean the upper and lower surfaces of the wafer, and the rolling cleaning brushes form the rolling cleaning portion; and The first spray assembly includes a first storage box and a first spray pipe connected to the first storage box. The first spray pipe is used to spray the cleaning medium in the first storage box toward the wafer.

3. The gallium nitride wafer chemical mechanical planarization device according to claim 1, wherein: The drying unit further includes a deep cleaning module, which includes: A second drive assembly includes a second driver and a plurality of drive wheels connected to the second driver, wherein the plurality of drive wheels enclose a rotation space for accommodating the wafer, and the second driver is used to drive the plurality of drive wheels to rotate around their own axes. The drive wheels drive the wafer to rotate around their own axes under the action of friction; A rotary cleaning assembly comprising a rotary drive and a rotary cleaning brush connected to the rotary drive, wherein the rotary cleaning brush is located above the wafer, and the axis of the rotary cleaning brush is parallel to the axis of the driving wheel, and the rotary drive is used to drive the rotary cleaning brush to rotate around its own axis to simultaneously clean the upper surface of the wafer; and The second spray assembly includes a second storage box and a second spray pipe connected to the second storage box. The second spray pipe is used to spray the cleaning medium in the second storage box toward the wafer.

4. The gallium nitride wafer chemical mechanical planarization device according to claim 1, wherein: The polishing unit comprises: A rotary robot arm comprising a rotary shaft and a plurality of rotary arms radially connected to the rotary shaft; and Multiple groups of polishing components are arranged in one-to-one correspondence with the multiple rotating arms. The polishing components include a polishing head connected to the rotating arm and a polishing disk arranged below the polishing head, and also include a guide pipe arranged on one side of the polishing disk.

5. The gallium nitride wafer chemical mechanical planarization device according to claim 4, wherein: The polishing unit further includes a loading platform, the rotary robot arm has the rotary arm corresponding to the loading platform, and the loading platform is used to carry a wafer.

6. The gallium nitride wafer chemical mechanical planarization device according to claim 4, wherein: The transfer unit comprises: A first transmission component is provided at one side of the front-end unit, the first transmission component includes a first guide rail and a first manipulator slidably connected to the first guide rail, and the first manipulator is used to grab the wafer; a second transport assembly disposed between the front-end unit and the polishing unit, the second transport assembly comprising a second guide rail and a second robot slidably connected to the second guide rail, and further comprising a transfer tray disposed between the first transport assembly and the second transport assembly, the transfer tray being used to receive wafers transferred by the first robot or the second robot; and The third transmission component is arranged between the second transmission component and the polishing component. The third transmission component includes a first transmission platform, a second transmission platform and a third robot. The third robot grabs and transmits the wafer on the first transmission platform or the second transmission platform.

7. The gallium nitride wafer chemical mechanical planarization device according to claim 4, wherein: The polishing unit further comprises a photocatalytic device disposed above the polishing disc, and the photocatalytic device is used for projecting ultraviolet rays toward the polishing disc.

8. The gallium nitride wafer chemical mechanical planarization device according to claim 4, wherein: An ultraviolet light projection lamp is provided in the polishing disc, and the ultraviolet light projection lamp is used to project ultraviolet light above the polishing disc.

9. The gallium nitride wafer chemical mechanical planarization device according to claim 4, wherein: An ultraviolet lamp is provided in the guide tube, and the ultraviolet lamp is used to maintain the reaction concentration of the polishing liquid.

10. A gallium nitride wafer chemical mechanical planarization process, characterized in that: include: S100, placing the wafer to be cleaned into a wafer box; S200: The transfer unit transfers the wafers in the wafer box to the polishing unit, and the polishing unit sequentially performs rough polishing, intermediate polishing, and fine polishing on the wafers, wherein the material removal rate for rough polishing is 3-6 μm / h, and the surface roughness Ra of the wafers after rough polishing is less than 1 nm; the material removal rate for intermediate polishing is 1-1.5 μm / h, and the surface roughness Ra of the wafers after rough polishing is less than 0.7 nm; the material removal rate for fine polishing is 0.5-0.7 μm / h, and the surface roughness Ra of the wafers after rough polishing is less than 0.5 nm; S300 , transferring the polished wafer to a drying unit, wherein the drying unit first cleans the residual dirt on the surface of the wafer and then dries the wafer.

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