Wafer polishing system, wafer polishing method, and wafer polishing control system

Abstract

The application discloses a wafer polishing system, a wafer polishing method and a wafer polishing control system. The wafer polishing system comprises a wafer polishing device and a recovery device. The wafer polishing device comprises a polishing disc assembly, at least three polishing heads and a liquid supply assembly corresponding to the polishing heads. The polishing heads are used for polishing wafers on the polishing disc assembly, and the liquid supply assembly is used for supplying polishing liquid to the polishing heads. The polishing disc assembly further comprises a liquid return hole arranged at the center and used for communicating with the recovery device. The recovery device comprises a filter used for filtering the recovered polishing liquid and a conditioning barrel used for conditioning the filtered polishing liquid to transmit the polishing liquid to the liquid supply assembly again. The scheme provided by the application can reduce the polishing liquid accumulated in the center of the polishing disc assembly, improve the polishing precision and save the polishing liquid cost.

Description

Technical Field

[0001] This application belongs to the field of wafer processing technology, and more specifically, relates to a wafer polishing system, a wafer polishing method, and a wafer polishing control system. Background Technology

[0002] In the manufacturing of integrated circuits (ICs), the surface flatness of wafers is required to be extremely high. Therefore, chemical mechanical polishing (CMP) is used to polish the wafer surface.

[0003] Third-generation semiconductor materials, with their wider bandgap, high thermal conductivity, high breakdown field strength, high saturated electron drift velocity, and high bonding energy, can meet the new requirements of modern electronic technology for harsh conditions such as high temperature, high power, high voltage, high frequency, and radiation resistance. As a result, third-generation semiconductor materials have wide applications in industries such as radio frequency communication, radar, satellite, power management, automotive electronics, and industrial power electronics.

[0004] However, third-generation semiconductor materials such as gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), and diamond have extremely high hardness and are difficult to polish, resulting in low polishing efficiency of chemical mechanical polishing (CMP) processes and high costs for polishing slurries. Summary of the Invention

[0005] This application provides a wafer polishing system, a wafer polishing method, and a wafer polishing control system, which aims to at least solve one of the technical problems existing in the prior art.

[0006] A first aspect of this application provides a wafer polishing system, comprising: a wafer polishing apparatus and a recycling apparatus; the wafer polishing apparatus includes: a polishing disk assembly, at least three polishing heads, and a liquid supply assembly corresponding to each polishing head, wherein the polishing heads are used to polish wafers on the polishing disk assembly, and the liquid supply assembly is used to supply polishing fluid to the polishing heads, wherein the polishing disk assembly includes a return fluid hole disposed at the center; the recycling apparatus includes: a filter for communicating with the return fluid hole for recycling and filtering the polishing fluid; and a modulation tank for modulating the filtered polishing fluid to transfer the polishing fluid back to the liquid supply assembly.

[0007] In one embodiment, the filter includes: a centrifugal deposition filter for centrifugally depositing impurity particles in the polishing fluid, wherein the centrifugal deposition filter is connected to the return fluid hole via a recovery fluid path; and a fine filter for finely filtering the polishing fluid and conveying the finely filtered polishing fluid to the preparation tank.

[0008] In one embodiment, the recycling device further includes a temperature controller, disposed on the recycling liquid line, for adjusting the temperature of the recycled polishing liquid.

[0009] In one embodiment, the temperature controller includes a fluid passage disposed below the polishing disc assembly and is also used to cool the polishing disc assembly.

[0010] In one embodiment, the liquid supply assembly includes: a liquid supply arm, a liquid supply path communicating with the liquid supply arm, and a nozzle disposed on the liquid supply arm; the liquid supply arm is used to move the nozzle between two adjacent polishing heads to supply polishing liquid to the polishing heads; wherein, the liquid supply arm is provided with a plurality of nozzles, and the nozzles are disposed in the area of ​​the liquid supply arm corresponding to the polishing heads.

[0011] In one embodiment, the supply arm is provided with a scraper, which is disposed on the supply arm corresponding to the area from the polishing head to the edge of the polishing disc assembly.

[0012] In one embodiment, the position of the scraper near the return hole coincides with the position of the nozzle away from the return hole.

[0013] A second aspect of this application provides a wafer polishing method, comprising: fixing a wafer with at least three polishing heads and abutting the fixed wafer against a polishing disk assembly; controlling a liquid supply assembly corresponding to each polishing head to spray polishing fluid, and controlling the polishing heads and the polishing disk assembly to perform chemical mechanical polishing on the wafer; controlling a filter to recover polishing fluid from a connected return port and filtering the recovered polishing fluid, wherein the return port is located at the center of the polishing disk assembly; and controlling a modulation tank to modulate the filtered polishing fluid to re-transfer the polishing fluid to the liquid supply assembly.

[0014] In one embodiment, the control modulation tank modulates the filtered polishing fluid to re-transfer the polishing fluid to the supply assembly, comprising: centrifugally depositing impurity particles in the polishing fluid through a centrifugal deposition filter, wherein the centrifugal deposition filter is connected to the return fluid hole through a recovery fluid path; finely filtering the polishing fluid through a fine filter and conveying the finely filtered polishing fluid to the modulation tank; modulating the polishing fluid in the modulation tank and re-transferring the polishing fluid to the supply assembly.

[0015] In one embodiment, before centrifugally depositing impurity particles in the polishing fluid through a centrifugal deposition filter, the method further includes: controlling a temperature controller set on the recovery fluid line to adjust the temperature of the polishing fluid recovered from the return fluid hole.

[0016] In one embodiment, the temperature controller includes a fluid passage disposed below the polishing disc assembly and is also used to cool the polishing disc assembly.

[0017] In one embodiment, controlling the liquid supply assembly corresponding to each polishing head to spray polishing liquid and controlling the polishing head and the polishing disc assembly to rotate includes: controlling the at least three polishing heads to rotate around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; driving the liquid supply arm to swing to the clearance space, so that the nozzle on the liquid supply arm moves between two adjacent polishing heads to supply polishing liquid to the polishing head, wherein the liquid supply arm is provided with a plurality of nozzles, and the nozzles are located in the area on the liquid supply arm corresponding to the polishing head.

[0018] A third aspect of this application provides a wafer polishing control system, comprising: a wafer polishing apparatus, a recovery apparatus, and a controller; the wafer polishing apparatus includes: a polishing disk assembly, at least three polishing heads, and a liquid supply assembly corresponding to each polishing head, the polishing heads being used to polish wafers on the polishing disk assembly, the liquid supply assembly being used to supply polishing fluid to the polishing heads, wherein the polishing disk assembly includes a return fluid hole disposed at the center; the recovery apparatus includes: a filter for communicating with the return fluid hole to recover and filter the polishing fluid; a modulation tank for modulating the filtered polishing fluid to transfer the polishing fluid back to the liquid supply assembly; the controller is used to control at least three polishing heads to fix wafers respectively and to abut the fixed wafers against the polishing disk assembly, to control the liquid supply assemblies corresponding to each polishing head to spray polishing fluid, to control the polishing heads and the polishing disk assembly to perform chemical mechanical polishing on the wafers, to control the filter to recover polishing fluid from the communicating return fluid hole and to filter the recovered polishing fluid, and to control the modulation tank to modulate the filtered polishing fluid to transfer the polishing fluid back to the liquid supply assembly.

[0019] In one embodiment, the controller is further configured to: control a centrifugal deposition filter to centrifuge and deposit impurity particles in the polishing fluid, wherein the centrifugal deposition filter is connected to the return fluid hole via a recovery fluid path; control a fine filter to finely filter the polishing fluid and deliver the finely filtered polishing fluid to a conditioning tank; condition the polishing fluid in the conditioning tank and deliver the polishing fluid to the supply assembly again.

[0020] In one embodiment, the controller is further configured to: control a temperature controller disposed on the recovery fluid line to adjust the temperature of the polishing fluid recovered from the return fluid hole.

[0021] In one embodiment, the controller is specifically configured to: control the at least three polishing heads to rotate around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; drive the liquid supply arm to swing to the clearance space, so that the nozzles on the liquid supply arm move between two adjacent polishing heads to supply polishing liquid to the polishing heads, wherein the liquid supply arm is provided with a plurality of nozzles, and the nozzles are disposed in the area on the liquid supply arm corresponding to the polishing heads.

[0022] The beneficial effects of this application are as follows: When polishing on a polishing pad assembly using at least three polishing heads, a return hole is provided at the center of the polishing pad assembly. This return hole allows the polishing fluid accumulated in the center of the polishing pad assembly to be transferred to a recycling device for recovery, reducing the amount of polishing fluid accumulated at the center of the assembly and improving polishing accuracy. Furthermore, the rotation of the polishing pad assembly and the polishing heads causes impurity particles generated during the polishing process to accumulate towards the center of the assembly. The return hole allows these impurity particles to be transferred along with the polishing fluid to the recycling device, reducing the number of impurity particles on the polishing pad and improving polishing accuracy. Additionally, the recovered polishing fluid can be filtered using a filter, and the filtered polishing fluid can be prepared using a preparation tank before being transferred back to the supply assembly, achieving the recycling and reuse of the polishing fluid and saving on polishing fluid costs. Attached Figure Description

[0023] The advantages of this application will become clearer and easier to understand through the detailed description in conjunction with the following accompanying drawings, which are merely illustrative and do not limit the scope of protection of this application, wherein:

[0024] Figure 1 This is a schematic diagram of an existing wafer polishing apparatus;

[0025] Figure 2 This is a schematic diagram of a wafer polishing system provided in one embodiment of this application;

[0026] Figure 3 This is a top view schematic diagram of a wafer polishing apparatus provided in an embodiment of this application;

[0027] Figure 4 This is a schematic diagram of the state of polishing fluid accumulating towards the center according to an embodiment of this application;

[0028] Figure 5 This is a schematic diagram of another wafer polishing system provided in an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a recycling device provided in one embodiment of this application;

[0030] Figure 7 This is a schematic diagram of a wafer polishing system with rough polishing and fine polishing provided in an embodiment of this application;

[0031] Figure 8 This is a schematic diagram of the structure of a wafer polishing system with a wafer transfer device provided in an embodiment of this application;

[0032] Figure 9 This is a schematic flowchart of a polishing method provided in an embodiment of this application. Detailed Implementation

[0033] The technical solutions described in this application will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of this application, used to illustrate the concept of this application; these descriptions are illustrative and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of this application. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and description of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0034] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of this application and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of this application, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0035] In this application, "Chemical Mechanical Polishing (CMP)" is also referred to as "Chemical Mechanical Planarization (CMP)".

[0036] In this application, a wafer (W) is also referred to as a substrate, crystal plate, or wafer, etc., with the same meaning and practical function.

[0037] The embodiments disclosed in this application generally relate to polishing equipment used in the semiconductor device manufacturing industry.

[0038] It should be noted that the solution / equipment provided in this application is mainly used for chemical mechanical polishing of wafers made of third-generation semiconductor materials. Specifically, it can be used for 4-inch, 6-inch, or 8-inch wafers processed from third-generation semiconductor materials, such as 4-inch, 6-inch, or 8-inch GaN wafers, or 8-inch SiC wafers.

[0039] In addition, due to the high difficulty in growing third-generation semiconductor materials, there are problems such as difficulty in controlling the temperature field, slow growth rate, high requirements for yield parameters, and difficulty in crystal diameter expansion. As a result, the wafer size of third-generation semiconductor materials is mainly 6-8 inches. With the development of technology and the overcoming of growth problems, the wafer size of third-generation semiconductor materials may expand to 12 inches or even larger. The solutions / equipment provided in this application are also applicable and are all within the protection scope of this application.

[0040] like Figure 1 As shown, the chemical mechanical polishing equipment includes a polishing head 101 for holding and rotating the wafer w, a polishing disc 103 covered with a polishing pad 102, a dresser 104 for dressing the polishing pad 102, and a liquid supply unit 105 for spraying polishing liquid.

[0041] During chemical mechanical polishing (CMP), the polishing head 101 presses the wafer w onto the polishing pad 102 covering the surface of the polishing disk 103. The polishing head 101 rotates and reciprocates radially along the polishing disk 103, gradually removing impurities from the surface of the wafer w in contact with the polishing pad 102. Simultaneously, the polishing disk 103 rotates, and the liquid supply unit 105 sprays polishing slurry onto the surface of the polishing pad 102. Under the chemical action of the polishing slurry, the relative movement between the polishing head 101 and the polishing disk 103 causes the wafer w to rub against the polishing pad 102 for polishing. During polishing, a dresser 104 is used to trim and activate the surface morphology of the polishing pad 102. The dresser 104 can remove impurity particles remaining on the surface of the polishing pad 102, such as abrasive particles in the polishing slurry and waste material detached from the surface of the wafer w. It can also smooth out surface deformation of the polishing pad 102 caused by abrasion.

[0042] However, third-generation semiconductor materials such as gallium nitride (GaN) and silicon carbide (SiC) have extremely high hardness and are difficult to polish. When using the aforementioned chemical mechanical polishing equipment, the time required to polish a wafer increases dramatically, as does the amount of polishing fluid consumed and the wear on the polishing pad.

[0043] To improve polishing efficiency, the inventors designed at least three polishing heads to polish the wafer simultaneously, thereby shortening the polishing time.

[0044] However, polishing at least three wafers simultaneously increases the amount of polishing slurry used by at least three times, leading to a significant increase in slurry costs. Furthermore, limited space makes it extremely difficult to trim the polishing pads using a trimmer during polishing, resulting in a small area available for trimming. Additionally, polishing at least three wafers simultaneously generates at least three times more impurity particles; both of these factors contribute to excessively rapid wear and tear on the polishing pads.

[0045] Furthermore, the rotation of the polishing disc assembly 11 and the three polishing heads 121 generates a weak water vortex at the center of the polishing disc assembly 11. This makes it easy for polishing fluid, contaminants, etc., to accumulate and grow in the central circular area, which can easily scratch the wafer, accelerate the wear of the retaining ring, and increase the risk of slippage.

[0046] For example, the outer side of the polishing head includes a retaining ring for fixing the wafer. In order to prevent the wafer edge from being "over-polished", the retaining ring is used to press the polishing pads at the wafer edge and the polishing pads below the wafer to the same height. At this time, the height of the polishing pad where the retaining ring is located is lower than the height of the polishing pads outside the retaining ring, which makes it easy for impurity particles to accumulate on the outer side of the retaining ring and for it to be easily worn.

[0047] When the retaining ring is severely worn, the contact area between the retaining ring and the polishing pad on the wafer plane decreases. This leads to a poorer holding effect of the retaining ring on the wafer, which may result in wafer slippage; a poorer pressing effect of the retaining ring on the polishing pad, resulting in a poorer polishing effect; and a higher probability that the centrally grown crystal will enter and scratch the wafer, leading to a lower wafer yield.

[0048] When at least three polishing heads are used to polish a wafer simultaneously, polishing fluid, contaminants, etc. accumulate in the center of the polishing pad assembly. When the accumulation area slightly overlaps with the retaining ring, the polishing fluid and contaminants in this overlapping area will increase the wear of the retaining ring. If the accumulation is severe and crystal growth occurs, the service life of the retaining ring will drop precipitously, possibly reduced to 1 / 10 of its normal life.

[0049] To at least address some of the aforementioned problems, embodiments of this application provide a wafer polishing system. For example... Figures 2-8 As shown, the wafer polishing system 100 includes: a wafer polishing device 10 and a recycling device 20.

[0050] The wafer polishing apparatus 10 includes: a polishing disk assembly 11, at least three polishing heads 121, and a liquid supply assembly 13 corresponding to each polishing head. The polishing head 121 is used to polish the wafer on the polishing disk assembly 11, and the liquid supply assembly 13 is used to supply polishing liquid to the polishing head 121.

[0051] The polishing disc assembly 11 also includes a return hole 111 located in the center for communicating with the recycling device 20 to recycle the polishing fluid.

[0052] In this embodiment, a polishing pad may be covered above the polishing disk assembly 11. At least three polishing heads 121 press the wafer onto the polishing pad covering the surface of the polishing disk assembly 11. The at least three polishing heads 121 rotate and reciprocate radially along the polishing disk assembly 11, so that the wafer surface in contact with the polishing pad is gradually polished. At the same time, the polishing disk assembly 11 rotates, and the liquid supply components 13 corresponding to the polishing heads 121 spray polishing liquid onto the surface of the polishing pad, supplying polishing liquid to the corresponding polishing heads 121.

[0053] The inventors discovered that by spraying polishing liquid onto the polishing disk assembly 11 through at least three liquid supply components 13, the amount of polishing liquid is relatively large. Furthermore, due to the rotation of the polishing disk assembly 11 and at least three polishing heads 121, the polishing liquid accumulates towards the center of the polishing disk assembly 11. This greatly affects the flatness of the liquid surface at the center of the polishing disk assembly 11, thereby affecting the polishing effect near the center of the polishing disk assembly 11 and greatly affecting the lifespan of the retaining ring on the polishing head.

[0054] Therefore, in this embodiment, a return hole 111 is provided at the center of the polishing disk assembly 11. The polishing liquid accumulated in the middle of the polishing disk assembly 11 can be transferred to the recycling device 20 through the return hole 111 to recycle the polishing liquid and reduce the polishing liquid accumulated in the center of the polishing disk assembly 11, thereby improving the polishing accuracy.

[0055] In addition, due to the rotation of the polishing pad assembly 11 and the polishing head 121, the impurity particles generated during the polishing process also accumulate towards the center of the polishing pad assembly 11. The impurity particles can be transferred to the recycling device 20 along with the polishing liquid through the return hole 111, which reduces the impurity particles on the polishing pad and improves the polishing accuracy.

[0056] Furthermore, in this embodiment, after the polishing slurry is transferred from the return hole 111 at the center of the polishing disc assembly 11 to the recycling device 20, the recycling device 20 can recycle and reuse the polishing slurry.

[0057] The recovery device 20 includes: a filter 21 for filtering the recovered polishing slurry; and a conditioning tank 22 for conditioning the filtered polishing slurry to transfer it back to the supply assembly.

[0058] The solution provided in this embodiment allows for the recycling of polishing fluid accumulated in the center of the polishing pad assembly by setting a return hole at the center of the assembly. This return hole allows the polishing fluid to be transferred to a recycling device for recovery, reducing the amount of polishing fluid accumulated in the center of the assembly and improving polishing accuracy. Furthermore, the rotation of the polishing pad assembly and the polishing heads causes impurities generated during the polishing process to accumulate towards the center of the assembly. The return hole allows these impurities to be transferred along with the polishing fluid to the recycling device, reducing the number of impurities on the polishing pad and improving polishing accuracy. The recycled polishing fluid can be filtered, and the filtered fluid can be modulated using a mixing tank before being transferred back to the supply assembly, achieving the recycling and reuse of the polishing fluid and saving on its cost.

[0059] The specific structures of the wafer polishing apparatus 10 and the recycling apparatus 20 are described below. It should be noted that this application uses three polishing heads 121 as an example for illustrative purposes, and this is not intended to limit the scope of this application. Other numbers of polishing heads 121, such as four polishing heads 121, are also within the scope of protection of this application.

[0060] In this embodiment, the wafer polishing apparatus 10 may further include a polishing head driving assembly 12 for driving at least three polishing heads 121 to polish the wafer on the polishing disk assembly 11; the at least three polishing heads 121 are disposed below a polishing head driving assembly 12 and move and rotate under its drive.

[0061] See Figure 2 The polishing head drive assembly 12 comprises a polishing head exchange drive assembly 122, a polishing head rotation drive assembly 123, a swing assembly 124, a pneumatic rotary joint assembly 125, and a polishing drive base 126. The polishing head exchange drive assembly 122 can drive three polishing heads to rotate and exchange around the center line of the polishing head drive assembly 122. The polishing head rotation drive assembly 123 simultaneously drives three polishing heads 121 to rotate around the center of the polishing head. The polishing drive base 126 is used to fix the polishing head 121. The polishing drive assembly is mounted on the frame assembly via the swing assembly 124. The swing assembly 124 causes the polishing drive assembly to move linearly between the polishing disc assembly 11 and the loading / unloading station 32 (load cup). It can load the unpolished wafer from the loading / unloading station 32 onto the polishing head 121, or unload the polished assembly from the polishing head 121 onto the loading / unloading station 32. The pneumatic rotary joint assembly 125 is used to stably supply air to the polishing head.

[0062] At least three polishing heads 121 can be moved onto the polishing pad assembly 11 by the polishing head drive assembly 12 to polish the wafer; after polishing is completed, the polishing head drive assembly 12 can remove the at least three polishing heads 121 from above the polishing pad assembly 11, and the polishing pad can be trimmed by the trimming assembly 14.

[0063] When polishing the wafer, polishing slurry can be supplied through the slurry supply assembly 13, which corresponds one-to-one with the polishing head 121. The polishing slurry supplied by the slurry supply assembly 13 can be prepared from the original solution or provided by the recovery device 20.

[0064] Specifically, in this embodiment, see Figure 3 The liquid supply assembly 13 includes: a liquid supply arm 131, a liquid supply path connected to the liquid supply arm 131, and a nozzle 132 disposed on the liquid supply arm 131; the liquid supply arm 131 is used to drive the nozzle 132 to move between two adjacent polishing heads 121 to supply polishing liquid to the polishing head 121.

[0065] In this embodiment, multiple polishing heads 121 and multiple liquid supply arms 131 can be arranged at intervals and evenly distributed circumferentially.

[0066] The initial position of the liquid supply arm 131 can be outside the polishing disc assembly 11. After the polishing head 121 moves above the polishing disc assembly 11, the liquid supply arm 131 can swing inward, and at least three polishing heads 121 can rotate around the axis of the polishing disc assembly 11 to provide clearance space for the liquid supply arm 131. The liquid supply arm 131 can swing into the clearance space, causing the nozzle 132 on the liquid supply arm 131 to move between two adjacent polishing heads 121 to supply polishing fluid to the polishing heads 121. The polishing heads 121 continuously rotate around the axis of the polishing disc assembly 11, causing the position of the clearance space to continuously change, and the liquid supply arm 131 also continuously swings, thereby moving between two adjacent polishing heads 121 through the continuously changing clearance space.

[0067] The nozzle 132 in the figure is only used to illustrate the relative position. The nozzle 132 is actually located on the side of the liquid supply arm 131 near the polishing disc assembly 11. Multiple nozzles 132 are provided on the liquid supply arm 131, and the nozzles 132 are located in the area of ​​the liquid supply arm 131 corresponding to the polishing head 121.

[0068] Specifically, in this embodiment, the nozzle 132 closer to the outer periphery of the polishing head 121 sprays polishing fluid at a higher speed than the nozzle 132 farther from the outer periphery of the polishing head 121, and the nozzle 132 closer to the center of the polishing disc assembly 11 sprays polishing fluid at a lower speed than the nozzle 132 farther from the center of the polishing disc assembly 11. In this embodiment, the radius of the nozzle is used to indicate the speed of the sprayed polishing fluid and does not represent the actual size of the nozzle.

[0069] When the supply arm 131 is equipped with multiple nozzles 132, the sprayed polishing liquid can be illustrated as follows: Figure 4 As shown. When the polishing slurry is first sprayed, it flows to each polishing head 121. As the polishing slurry is continuously sprayed... Figure 4 As shown, the polishing fluid accumulates at the center of the polishing disc assembly 11 and is transferred to the recycling device 20 through the return fluid hole 111.

[0070] Optionally, in this embodiment, see Figure 3 A scraper 133 is provided on the liquid supply arm 131, and the scraper 133 is located on the liquid supply arm 131 corresponding to the area from the polishing head 121 to the edge of the polishing disc assembly 11. By providing the scraper 133, the polishing liquid can be guided to flow to the polishing head 121 and further accumulate towards the center of the polishing disc assembly 11, thereby improving the polishing effect.

[0071] Furthermore, the position of the scraper 133 near the return hole 111 coincides with the position of the nozzle away from the return hole 111. Since the polishing liquid moves outward under centrifugal force on the outside of the polishing disc assembly 11, the fact that one end of the scraper 133 coincides with the position of the nozzle on the outside allows the scraper 133 to guide most of the polishing liquid, increasing the efficiency of the scraper 133 in guiding the liquid, reducing the chance of the polishing liquid being thrown out of the polishing disc assembly 11, and further allowing the polishing liquid to accumulate towards the center of the polishing disc assembly 11. It can then be transferred to the recycling device 20 through the return hole 111, where the polishing liquid is recycled and reused through the filter 21 and the mixing tank 22 of the recycling device 20.

[0072] The recovery device 20 includes: a filter 21 for filtering the recovered polishing slurry; and a conditioning tank 22 for conditioning the filtered polishing slurry to transfer it back to the supply assembly.

[0073] In this embodiment, to improve the recovery efficiency of the polishing slurry, the temperature of the polishing slurry can be adjusted first. Optionally, in this embodiment, see... Figure 5 The recovery device 20 also includes a temperature controller 24, which is installed on the recovery liquid path 23 and is used to adjust the temperature of the recovered polishing liquid.

[0074] In this embodiment, the return liquid hole 111 can be located at the center of the polishing pad covering the polishing disk assembly 11 and connected to the rotating shaft of the polishing disk assembly 11. One end of the recovery liquid path 23 can be located inside the rotating shaft of the polishing disk assembly 11 and connected to the return liquid hole 111, and the other end can be connected to the recovery device.

[0075] The temperature controller 24 may include a fluid passage disposed in the rotating shaft of the polishing disc assembly 11 and a liquid pump connected to the fluid passage. The liquid pump can guide the coolant to flow in the fluid passage. The fluid passage can be arranged around the recovery liquid passage 23 to cool the polishing liquid.

[0076] In this embodiment, if the temperature controller 24 includes a fluid passage and the fluid passage is also disposed below the polishing disk assembly 11, it is also used to cool the polishing disk assembly 11.

[0077] Specifically, the main body of the polishing disc assembly 11 can be a hollow structure, and the fluid passage can be set inside the hollow structure. One end of the fluid passage is used for the flow of coolant, and the other end is arranged around the recovery fluid passage 23 and flows out of the coolant. Thus, the polishing disc assembly 11 and the polishing fluid are cooled simultaneously through one fluid passage, which reduces structural complexity and improves efficiency. Furthermore, by controlling a temperature controller, the polishing disc assembly and the recovered polishing fluid can be cooled simultaneously, which reduces structural complexity and improves efficiency.

[0078] A temperature sensor may also be provided on the polishing pad assembly 11 to detect the temperature of the polishing pad covering the polishing pad assembly 11. In this embodiment, the flow rate of the coolant in the fluid passage can also be controlled according to the temperature sensor to cool down the polishing pad assembly 11 and the recovered polishing fluid. The cooled polishing fluid can be transferred to the filter 21.

[0079] See Figure 5 The filter 21 includes: a centrifugal deposition filter 211, which is connected to the return liquid hole 111 through the recovery liquid path 23, and is used to centrifuge and deposit impurity particles in the polishing liquid; and a fine filter 212, which is connected to the centrifugal deposition filter 211, and is used to finely filter the polishing liquid.

[0080] In this embodiment, since the impurity particles present in the polishing slurry mainly include abrasive particles from chemical mechanical polishing and particles that fall off from the wafer during the polishing process, these particles may accumulate and grow, resulting in a large difference in the size of the impurity particles in the polishing slurry. The centrifugal deposition filter 211 can filter out the larger impurity particles in the polishing slurry, and the fine filter 212 can filter out the residual impurity particles in the polishing slurry. The finely filtered polishing slurry can be transferred to the mixing tank 22 for mixing to obtain a polishing slurry that meets the polishing requirements, and then transferred to the liquid supply assembly 13 to be sprayed again onto the surface of the polishing disc assembly 11 for polishing, which greatly reduces the cost of the polishing slurry.

[0081] The centrifugal sedimentation filter 211 may include an inlet located at the top for communication with a reflux port, an outlet located in the middle for directing the polishing fluid to the fine filter 212, and a waste outlet located at the bottom for discharging waste fluid mixed with a large number of impurity particles. The centrifugal sedimentation filter 211 may also include a level sensor and a stirrer, which can be controlled by a processor. When the level sensor detects a liquid level, indicating that the collected polishing fluid has reached a certain amount, the stirrer can be activated to agitate the polishing fluid in the centrifugal sedimentation filter 211, causing impurity particles to settle at the bottom, while the polishing fluid mixed with a small amount of impurity particles remains in the upper middle section. The polishing fluid in the middle section is then transferred to the fine filter 212 through the outlet, and the waste fluid mixed with a large number of impurity particles is discharged through the waste outlet at the bottom. The fine filter 212 can perform fine filtration on the polishing fluid mixed with a small amount of impurity particles. The level of fine filtration can be set according to the size of the impurity particles, which will not be elaborated in this embodiment. Specifically, the fine filter 212 can employ membrane filtration technology, specifically reverse osmosis, nanofiltration, ultrafiltration, and microfiltration, depending on the requirements.

[0082] To further reduce pollution, waste liquid from centrifugal sedimentation filter 211 and / or particulate matter from fine filter can be recovered.

[0083] Specifically, see Figure 6 The centrifugal sedimentation filter 211 may include an inlet, an outlet, and a waste liquid outlet. The waste liquid outlet can be connected to the inlet of the particulate matter recovery device 25 to discharge waste liquid into the particulate matter recovery device 25. Similarly, the fine filter 212 can be cleaned by rinsing or other methods, and the cleaned wastewater can also be input into the particulate matter recovery device 25 for particulate matter recovery treatment.

[0084] The finely filtered polishing slurry can be transferred to the mixing tank 22 for mixing. Specifically, the mixing tank 22 can transfer the polishing slurry to another mixing device for mixing, or it can transfer other mixing materials to the mixing tank 22 for mixing, all of which are within the scope of protection of this application.

[0085] The preparation tank can include multiple tanks, each used to deionize the finely filtered polishing solution, adjust its concentration, add buffer solution or polishing agent, add abrasive, etc., until a polishing solution that meets the polishing requirements is obtained.

[0086] Additionally, see Figure 7 Chemical mechanical polishing can be divided into two stages: rough polishing and fine polishing. The polishing liquid from both stages can be recycled, and the recycled polishing liquid can be reused in the rough polishing stage.

[0087] like Figure 8As shown, in this embodiment, the wafer polishing system 100 further includes a wafer transport device 30.

[0088] The wafer transfer device 30 includes: a buffer station 31 for buffering wafers; at least two loading / unloading stations 32 for loading / unloading wafers; a horizontal robot 33 for moving wafers between multiple buffer stations; and a swapping robot 34 for moving wafers between the loading / unloading stations 32 and the buffer station 31.

[0089] In this embodiment, taking the wafer polishing system 100 as an example, there are two sets of wafer polishing devices 10. Each set of wafer polishing devices 10 corresponds to two loading and unloading stations 32 and three buffer stations 31. A buffer station 31 is also provided between the two sets of wafer polishing devices 10.

[0090] During polishing, a horizontal robot arm 33 moves wafers to multiple buffer stations 31, and a swapping robot arm 34 moves the wafers from the buffer stations 31 to the loading / unloading station 32. The polishing head 111 can then load wafers from the loading / unloading station 32 for polishing. After polishing, the wafers can be unloaded to the loading / unloading station 32, and the swapping robot arm 34 moves the wafers from the loading / unloading station 32 to the buffer station 31, thus removing the wafers.

[0091] Another embodiment of this application provides a wafer polishing method using the above-described wafer polishing apparatus, such as... Figure 9 As shown, it includes:

[0092] S1. Fix the wafer with at least three polishing heads and bring the fixed wafer into contact with the polishing disk assembly.

[0093] S2. Control the liquid supply components corresponding to the polishing heads to spray polishing liquid, and control the polishing heads and the polishing disk components to perform chemical mechanical polishing on the wafers.

[0094] S3. Control the filter to recover polishing fluid from the connected return hole and filter the recovered polishing fluid, wherein the return hole is located at the center of the polishing disc assembly.

[0095] S4. Control the modulation tank to modulate the filtered polishing liquid so as to transfer the polishing liquid to the liquid supply component again.

[0096] In this embodiment, when polishing is performed on the polishing pad assembly using at least three polishing heads, a return hole is provided at the center of the polishing pad assembly. This return hole allows the polishing fluid accumulated in the center of the polishing pad assembly to be transferred to a recycling device for recovery, reducing the amount of polishing fluid accumulated at the center of the assembly and improving polishing accuracy. Furthermore, the rotation of the polishing pad assembly and the polishing heads causes impurity particles generated during the polishing process to accumulate towards the center of the assembly. The return hole allows these impurity particles to be transferred along with the polishing fluid to the recycling device, reducing the number of impurity particles on the polishing pad and improving polishing accuracy. Additionally, the recovered polishing fluid can be filtered using a filter, and the filtered polishing fluid can be modulated using a modulation tank before being transferred back to the supply assembly, achieving the recycling and reuse of the polishing fluid and saving on polishing fluid costs.

[0097] Optionally, in this embodiment of the application, the control modulation tank modulates the filtered polishing liquid to transmit the polishing liquid to the supply component again, including: centrifugally depositing impurity particles in the polishing liquid through a centrifugal deposition filter, wherein the centrifugal deposition filter is connected to the return liquid hole through a recovery liquid path; finely filtering the polishing liquid through a fine filter and conveying the finely filtered polishing liquid to the modulation tank; modulating the polishing liquid in the modulation tank and transmitting the polishing liquid to the supply component again.

[0098] Optionally, in this embodiment of the application, before centrifugally depositing impurity particles in the polishing fluid through a centrifugal deposition filter, the method further includes: controlling a temperature controller set on the recovery fluid line to adjust the temperature of the polishing fluid recovered from the return fluid hole.

[0099] Optionally, in this embodiment of the application, the temperature controller includes a fluid passage disposed below the polishing disc assembly and is also used to cool the polishing disc assembly.

[0100] Optionally, in this embodiment of the application, controlling the liquid supply assembly corresponding to each polishing head to spray polishing liquid and controlling the polishing head and the polishing disc assembly to rotate includes: controlling the at least three polishing heads to rotate around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; driving the liquid supply arm to swing to the clearance space, so that the nozzle on the liquid supply arm moves between two adjacent polishing heads to supply polishing liquid to the polishing head, wherein the liquid supply arm is provided with a plurality of nozzles, and the nozzles are disposed in the area on the liquid supply arm corresponding to the polishing head.

[0101] The structure of the wafer polishing apparatus and the recycling apparatus can be as described in the above embodiments, and the control logic for controlling the wafer polishing apparatus can also be as described in the above embodiments, which will not be repeated here.

[0102] Another embodiment of this application provides a wafer polishing control system, including: a wafer polishing apparatus, a recovery apparatus, and a controller; the wafer polishing apparatus includes: a polishing disk assembly, at least three polishing heads, and a liquid supply assembly corresponding to each polishing head, the polishing head being used to polish the wafer on the polishing disk assembly, the liquid supply assembly being used to supply polishing fluid to the polishing head, wherein the polishing disk assembly includes a return fluid hole disposed at the center; the recovery apparatus includes: a filter being used to communicate with the return fluid hole for recovering and filtering the polishing fluid; a modulation tank being used to modulate the filtered polishing fluid to transfer the polishing fluid back to the liquid supply assembly; the controller being used to control at least three polishing heads to fix wafers respectively and to abut the fixed wafers against the polishing disk assembly, to control the liquid supply assembly corresponding to each polishing head to spray polishing fluid, to control the polishing head and the polishing disk assembly to perform chemical mechanical polishing on the wafer, to control the filter to recover polishing fluid from the communicating return fluid hole and to filter the recovered polishing fluid, and to control the modulation tank to modulate the filtered polishing fluid to transfer the polishing fluid back to the liquid supply assembly.

[0103] In one embodiment, the controller is further configured to: control a centrifugal deposition filter to centrifuge and deposit impurity particles in the polishing fluid, wherein the centrifugal deposition filter is connected to the return fluid hole via a recovery fluid path; control a fine filter to finely filter the polishing fluid and deliver the finely filtered polishing fluid to a conditioning tank; condition the polishing fluid in the conditioning tank and deliver the polishing fluid to the supply assembly again.

[0104] In one embodiment, the controller is further configured to: control a temperature controller disposed on the recovery fluid line to adjust the temperature of the polishing fluid recovered from the return fluid hole.

[0105] In one embodiment, the controller is specifically configured to: control the at least three polishing heads to rotate around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; drive the liquid supply arm to swing to the clearance space, so that the nozzles on the liquid supply arm move between two adjacent polishing heads to supply polishing liquid to the polishing heads, wherein the liquid supply arm is provided with a plurality of nozzles, and the nozzles are disposed in the area on the liquid supply arm corresponding to the polishing heads.

[0106] The structure of the wafer polishing apparatus and the recycling apparatus can be as described in the above embodiments, and the control logic for controlling the wafer polishing apparatus can also be as described in the above embodiments, which will not be repeated here.

[0107] Another embodiment of this application provides a computer-readable storage medium having executable instructions stored thereon, which, when a processor executes the executable instructions, implement the method described above.

[0108] Another embodiment of this application provides a computer program product or computer program, which includes executable instructions stored in a computer-readable storage medium; the above method is implemented when the processor of an electronic device reads the executable instructions from the computer-readable storage medium and executes the executable instructions.

[0109] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A wafer polishing system, characterized in that, include: Wafer polishing equipment and recycling equipment; The wafer polishing apparatus includes: a polishing disk assembly, at least three polishing heads, and a liquid supply assembly corresponding to each polishing head. The polishing heads are used to polish wafers on the polishing disk assembly, and the liquid supply assemblies are used to supply polishing fluid to the polishing heads. The polishing disk assembly includes a centrally located return port. The liquid supply assembly includes a supply arm and a nozzle mounted on the supply arm. A scraper is mounted on the supply arm, with one end of the scraper near the return port coinciding with the end of the nozzle away from the return port. The recovery device includes: a centrifugal deposition filter. The system includes a centrifugal deposition filter for centrifuging and depositing impurity particles in the polishing slurry, wherein the centrifugal deposition filter is connected to the return hole via a recovery liquid path; a fine filter is used to finely filter the polishing slurry and transport the finely filtered polishing slurry to a conditioning tank; a conditioning tank is used to condition the filtered polishing slurry to transport it again to the supply assembly; and a temperature controller is located on the recovery liquid path to adjust the temperature of the recovered polishing slurry, the temperature controller including a fluid passage located below the polishing disc assembly and also used to cool the polishing disc assembly.

2. The wafer polishing system according to claim 1, characterized in that, The liquid supply assembly further includes a liquid supply path connected to the liquid supply arm; the liquid supply arm is used to move the nozzle between two adjacent polishing heads to supply polishing liquid to the polishing heads; wherein, the liquid supply arm is provided with a plurality of nozzles, and the nozzles are located in the area of ​​the liquid supply arm corresponding to the polishing heads.

3. The wafer polishing system according to claim 1, characterized in that, The scraper is positioned on the liquid supply arm corresponding to the area from the polishing head to the edge of the polishing disc assembly.

4. A wafer polishing method, characterized in that, include: A wafer is fixed by at least three polishing heads, and the fixed wafers abut against a polishing disk assembly. A liquid supply assembly corresponding to each polishing head sprays polishing fluid, and the polishing heads and the polishing disk assembly perform chemical mechanical polishing on the wafers. Impurities in the polishing fluid are centrifugally deposited through a centrifugal deposition filter, wherein the centrifugal deposition filter is connected to a return liquid port via a recovery liquid path, and the return liquid port is located at the center of the polishing disk assembly. The liquid supply assembly includes a supply arm and a nozzle mounted on the supply arm. A scraper is mounted on the supply arm, and one end of the scraper near the return liquid port is connected to... The nozzles are positioned so that the ends furthest from the return hole coincide; the polishing fluid is finely filtered through a fine filter and then transported to a mixing tank; the polishing fluid in the mixing tank is mixed and then transported back to the supply assembly; wherein, before the impurity particles in the polishing fluid are centrifugally deposited through a centrifugal deposition filter, the method further includes: controlling a temperature controller located on the recovery fluid path to adjust the temperature of the polishing fluid recovered from the return hole; the temperature controller includes a fluid passage located below the polishing disc assembly and is also used to cool the polishing disc assembly.

5. The method according to claim 4, characterized in that, The control of the liquid supply assembly corresponding to each polishing head to spray polishing liquid, and the control of the rotation of the polishing head and the polishing disc assembly, includes: controlling the rotation of at least three polishing heads around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; driving the liquid supply arm to swing to the clearance space, so that the nozzle on the liquid supply arm moves between two adjacent polishing heads to supply polishing liquid to the polishing head, wherein the liquid supply arm is provided with multiple nozzles, and the nozzles are located in the area on the liquid supply arm corresponding to the polishing head.

6. A wafer polishing control system, characterized in that, include: Wafer polishing equipment, recycling equipment, and controllers; The wafer polishing apparatus includes: a polishing disk assembly, at least three polishing heads, and a liquid supply assembly corresponding to each polishing head. The polishing heads are used to polish wafers on the polishing disk assembly, and the liquid supply assemblies supply polishing fluid to the polishing heads. The polishing disk assembly includes a centrally located return port. The liquid supply assembly includes a supply arm and a nozzle mounted on the supply arm. A scraper is mounted on the supply arm, with one end of the scraper near the return port coinciding with the end of the nozzle away from the return port. The recovery device includes: a centrifugal deposition filter for centrifugally depositing impurity particles in the polishing fluid, wherein the centrifugal deposition filter is connected to the return port via a recovery fluid path; a fine filter for finely filtering the polishing fluid and conveying the filtered polishing fluid to a conditioning tank; and a conditioning tank for conditioning the filtered polishing fluid for re-transferring the polishing fluid. The system includes a liquid supply assembly and a temperature controller, located on the recovery liquid path, for adjusting the temperature of the recovered polishing liquid. The temperature controller includes a fluid passage located below the polishing disc assembly and is also used to cool the polishing disc assembly. The controller controls at least three polishing heads to fix wafers and bring the fixed wafers into contact with the polishing disc assembly. It controls the liquid supply assembly corresponding to each polishing head to spray polishing liquid and controls the polishing heads and the polishing disc assembly to perform chemical mechanical polishing on the wafers. It controls a centrifugal deposition filter to centrifuge and deposit impurity particles in the polishing liquid. It controls a fine filter to finely filter the polishing liquid and transport the finely filtered polishing liquid to a conditioning tank. It also conditions the polishing liquid in the conditioning tank and transmits the polishing liquid back to the liquid supply assembly. Finally, it controls the temperature controller to adjust the temperature of the polishing liquid recovered from the return liquid hole.

7. The wafer polishing control system according to claim 6, characterized in that, The controller is specifically used to: control the at least three polishing heads to rotate around the axis of the polishing disc assembly to provide clearance space for the liquid supply arm; drive the liquid supply arm to swing to the clearance space, so that the nozzle on the liquid supply arm moves between two adjacent polishing heads to supply polishing liquid to the polishing heads, wherein the liquid supply arm is provided with multiple nozzles, and the nozzles are located in the area on the liquid supply arm corresponding to the polishing heads.

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