Device and method for removing local large particles on surface of polished section

Abstract

The invention relates to the technical field of semiconductor single crystal polished wafer substrate manufacturing, in particular to a device and method for removing local large particles on the surface of a polished wafer, and the device comprises dry cleaning equipment which comprises a polished wafer carrying table, and a vacuum adsorption pipeline is arranged in the polished wafer carrying table; a to-be-processed polishing piece is installed on the top of the polishing piece carrying table, and submicron particles are arranged on the surface of the polishing piece. And a cleaning system is arranged at the upper part of the to-be-processed polished wafer. According to the device and method for removing the local large particles on the surface of the polished wafer, local submicron particle contamination on the surface of the polished wafer can be accurately removed, and the problems that the roughness of the polished surface becomes poor and a back sealing film is thinned possibly due to whole wafer cleaning in the traditional wet cleaning process are solved. The dry cleaning technology is adopted, particles are removed through high-purity N2 and ultrasonic energy, corrosion and damage of a chemical solution to the surface of the polished wafer are avoided, and meanwhile the completeness of the back sealing film is kept.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor single crystal polishing wafer substrate manufacturing, and more specifically, to a device and method for removing local large particles on the surface of a polishing wafer. Background Art

[0002] The polishing wafer cleaning technology widely adopts the traditional RCA wet cleaning process. Its conventional process is solution immersion cleaning combined with cleaning auxiliary means such as megasonic cleaning, spray type, and fast discharge type to improve the surface particle removal ability. After wet cleaning, a spin dryer, IPA drying and other equipment are used for drying treatment. However, during the chemical mechanical polishing (CMP) process and the process of transfer and transportation after cleaning, the polishing may be contaminated by various sources of particles (micrometer-sized particles), such as polishing slurry, polishing pad, polishing equipment, cleaning equipment, storage containers, and the environment. The final particle level on the surface of the polishing wafer is crucial for the yield of subsequent processes. Therefore, there are extremely high requirements for the particle size and quantity on the surface. For example, for an 8-inch polishing wafer, the particle requirements are ф >= 0.16um, <= 40ea / pcs, ф >= 0.2um, <= 15ea / pcs, ф >= 0.3um, <= 9ea / pcs, ф >= 0.5um, <= 4ea / pcs. The particles on the surface of the polishing wafer can usually be removed to a certain number after one RCA cleaning to meet the cleanliness requirements of subsequent processes. However, some stubbornly attached particles and recontaminated particles will still cause a certain proportion (about 5% - 15%) of defects.

[0003] The current technology usually removes sub-micron particle contamination by repeated wet cleaning, but this technology will cause a decrease in the front surface accuracy of the polishing wafer and thinning of the back-sealing film, resulting in the scrapping of the polishing wafer. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for removing local large particles on the surface of a polishing wafer, so as to solve the problem that the current technology usually removes sub-micron particle contamination by repeated wet cleaning, but this technology will cause a decrease in the front surface accuracy of the polishing wafer and thinning of the back-sealing film, resulting in the scrapping of the polishing wafer as mentioned in the above background art.

[0005] To achieve the above purpose, the present invention provides a device and method for removing local large particles on the surface of a polishing wafer, including a dry cleaning device. The dry cleaning device includes a polishing wafer stage. A vacuum adsorption pipeline is arranged inside the polishing wafer stage. A polishing wafer to be processed is installed on the top of the polishing wafer stage. Sub-micron particles are carried on the surface of the polishing wafer. A cleaning system is arranged above the polishing wafer to be processed.

[0006] The cleaning system includes an upper integrated bin, a lower integrated bin is installed at the bottom of the upper integrated bin, a gas distribution bin is installed at the top of the upper integrated bin, an N2 intake pipe and an acidic gas intake pipe are connected to the top of the gas distribution bin, a high-frequency ultrasonic generator is installed in the middle of the bottom of the upper integrated bin, the top of the high-frequency ultrasonic generator passes through the upper integrated bin and is connected to the gas distribution bin, the bottom of the high-frequency ultrasonic generator is connected to a main intake cavity, and a main gas spray head is installed at the bottom of the main intake cavity;

[0007] High-purity side intake cavities are provided on both inner walls of the lower integrated bin, the top end of the high-purity side intake cavity is connected to the gas distribution bin, and a side gas spray head is installed at the bottom end of the high-purity side intake cavity;

[0008] A gas recovery cavity is arranged inside the lower integrated bin, the bottom end of the gas recovery cavity is located above the polishing pad, the top end of the gas recovery cavity is communicated with the upper integrated bin, exhaust pipes are communicated at both ends of the upper integrated bin, and an air extraction port is arranged at the outer end of the exhaust pipe.

[0009] As a preferred solution of the present invention, the spraying direction of the side gas spray head is the horizontal direction, and a baffle is installed below the side gas spray head.

[0010] As a preferred solution of the present invention, it further includes an integrated locator and a mechanical motion system. The cleaning system is driven by the mechanical motion system to move in the XYZ three-axis directions. The integrated locator receives the particle detector or the set particle position information and controls the operation of the mechanical motion system;

[0011] As a preferred solution of the present invention, the exhaust pipe is of an L-shaped structure. The vertical end of the exhaust pipe passes through the upper integrated bin and is communicated with the gas recovery cavity. The horizontal end of the exhaust pipe is connected to the air extraction port, and a dust collection tank is connected to the bottom of the bend of the exhaust pipe.

[0012] As a preferred solution of the present invention, valves are installed on both the N2 intake pipe and the acidic gas intake pipe, and a flow regulator is installed on the gas distribution bin.

[0013] As a preferred solution of the present invention, the distance between the main gas spray head and the side gas spray head from the surface of the polishing pad is 1-5 mm; the distance between the bottom end of the gas recovery cavity from the surface of the polishing pad is 0.5-4.5 mm; the caliber of the main gas spray head is 0.2-0.5 mm.

[0014] As a preferred solution of the present invention, the power of the high-frequency ultrasonic generator is 500-3000 W, and the frequency is 10-40 KHz.

[0015] The present invention also provides a method for removing local large particles on the surface of a polishing wafer, which is used for the device for removing local large particles on the surface of a polishing wafer according to any one of claims 1-7, and includes the following steps:

[0016] S1. Place the cleaned polishing wafer in a particle analyzer for detection, and transmit the position information of sub-micron particles therein to an integrated locator;

[0017] S2. Transfer the polishing wafer to be processed to a polishing wafer stage through a manipulator, and fix it on the polishing wafer stage through a vacuum adsorption pipeline;

[0018] S3. The integrated locator transmits the particle position information to a mechanical motion system, and the mechanical motion system drives a cleaning system to perform XYZ-axis motion and place the cleaning system above the position of the sub-micron particles;

[0019] S4. After the high-purity N2 introduced through the intake pipeline enters the gas distribution chamber, it is divided into two paths. One path forms tiny vibrating bubbles through a high-frequency ultrasonic generator. These bubbles pass through the main intake chamber and then reach the main nozzle to be sprayed onto the surface of the sub-micron particles and quickly burst, releasing huge energy. This energy can shake off the sub-micron particles on the surface of the object; the other path passes through the side intake chamber to the side gas nozzle and acts on the sub-micron particles. The baffle can effectively prevent the fallen contaminants from falling onto the surface of the polishing wafer again;

[0020] S5. The shaken-off sub-micron particles then enter the exhaust pipeline through the gas recovery chamber by high-purity N2. A dust collection tank is connected to the lower end of the exhaust pipeline to prevent the particles from flowing back with the gas. The exhaust pipeline is connected to a vacuum pump through an air extraction port;

[0021] S6. Keep the cleaning system and the position of the polishing wafer unchanged. The high-purity N2 carrying dilute acid vapor enters the gas distribution chamber through the intake pipeline and is divided into two paths. One path forms tiny vibrating bubbles through an ultrasonic generator. These bubbles pass through the main intake chamber and then reach the main nozzle to be sprayed onto the local surface of the polishing wafer to be processed and quickly burst to dissolve the metal contaminants into the gas; the other path passes through the side intake chamber to the side gas nozzle and acts on the local surface of the polishing wafer; then the gas enters the exhaust pipeline through the gas recovery chamber.

[0022] S7. Keep the cleaning system and the position of the polishing wafer unchanged, close the intake pipeline. After the high-purity N2 enters the gas distribution chamber through the air intake port, it passes through the side intake chamber to the side gas nozzle and acts on the local surface of the polishing wafer; the above gas enters the exhaust pipeline through the gas recovery chamber.

[0023] S8. After the cleaning is completed, close all intake and exhaust pipelines. The integrated locator then transmits a signal to the robotic arm to return the cleaning system to its initial position, and inspect and pack the processed polishing wafer.

[0024] As a preferred embodiment of the present invention, the submicron particles in step S1 are submicron-level organic substances and dust contaminants that are re-contaminated during operations such as transfer and inspection after cleaning, with a particle size of 0.2 - 10 μm and a quantity of 1 - 3 particles per wafer.

[0025] As a preferred embodiment of the present invention, the polishing wafer is positioned in step S2 by using the reference surface or Notch groove of the polishing wafer, with a vacuum adsorption pressure of -5 KPa to -90 KPa, and the diameter of the vacuum adsorption pipeline is 10 mm smaller than the diameter of the polishing wafer to be processed; the N2 in step S4 is high-purity N2 with a flow rate of 5 - 50 ml / s; the dilute acid in step S6 is HCl or HF with a concentration of 0.05% - 0.1%, which is generated by carrying it after introducing N2 into the acid solution of configured HCl or HF, and the pumping rate of the air pump in steps S5, S6, and S7 is 10 - 80 ml / s.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. In the device and method for removing local large particles on the surface of the polishing wafer, it can accurately remove local submicron-level particle contaminants on the surface of the polishing wafer, avoiding the problems of deteriorated surface roughness of the polishing surface and thinning of the back-sealing film that may occur during the whole-wafer cleaning process in the traditional wet cleaning method.

[0028] 2. In the device and method for removing local large particles on the surface of the polishing wafer, a dry cleaning technique is adopted, using high-purity N2 and ultrasonic energy to remove particles, avoiding corrosion and damage to the surface of the polishing wafer by chemical solutions, and at the same time maintaining the integrity of the back-sealing film.

[0029] 3. In the device and method for removing local large particles on the surface of the polishing wafer, it can not only remove physically adsorbed submicron-level particles, but also remove metal contaminants through high-purity N2 carrying dilute acid vapor, meeting the dual requirements of particle cleanliness and metal cleanliness of the polishing wafer. Moreover, it is designed with a side air inlet cavity, side nozzles, and baffles, effectively preventing the removed particles from falling back onto the surface of the polishing wafer again. At the same time, the dust collection tank connected to the lower end of the exhaust pipeline prevents particles from flowing back with the gas, ensuring the cleaning effect.

[0030] 4. In the device and method for removing local large particles on the surface of the polishing wafer, after cleaning, the surface of the polishing wafer is purged with high-purity N2 to reduce the contact between the polishing wafer and O2, avoiding the risk of possible contamination during the equipment operation process, keeping the surface of the polishing wafer clean. Through the local cleaning technique, unnecessary whole-wafer cleaning steps are reduced, improving production efficiency and the yield of the polishing wafer, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the device of the present invention;

[0032] Figure 2 Schematic diagram of the operation steps of the present invention;

[0033] Figure 3 Schematic diagram of Embodiment 1 of the present invention;

[0034] Figure 4 Schematic diagram of Embodiment 2 of the present invention;

[0035] Figure 5 Schematic diagram of the particles adsorbed on the surface of the polished wafer of the present invention;

[0036] Figure 6 Schematic diagram of the process of the airflow carrying microbubbles to reach the surface of the polished wafer and the particles and burst;

[0037] Figure 7 Schematic diagram of the process of the particles on the surface of the polished wafer being blown by the high-speed nitrogen purge force of the present invention;

[0038] Figure 8 Schematic diagram of the process of the removed particles being removed by the pumping force of the air pump of the present invention;

[0039] The meanings of the various reference numerals in the figure are as follows:

[0040] 1. Polished wafer stage; 2. Vacuum adsorption pipeline; 22. Chemical bond; 23. Microbubble; 3. Submicron particle; 4. Polished wafer; 5. Integrated locator; 6. Mechanical motion system; 7. High-purity N2 intake pipeline; 8. Acid gas intake pipeline; 9. Gas distribution chamber; 10. Upper integrated chamber; 11. High-frequency ultrasonic generator; 12. Main intake chamber; 13. Side intake chamber; 14. Main gas nozzle; 15. Side gas nozzle; 16. Baffle; 17. Gas recovery chamber; 18. Exhaust pipeline; 19. Dust collection tank; 20. Air extraction port; 21. Lower integrated chamber. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] The present invention provides a device for removing local large particles on the surface of a polished wafer, as Figure 1 shown, including a dry cleaning device, the dry cleaning device includes a polished wafer stage 1, a vacuum adsorption pipeline 2 is arranged inside the polished wafer stage 1, a polished wafer 4 to be processed is installed on the top of the polished wafer stage 1, and submicron particles 3 are carried on the surface of the polished wafer 4; a cleaning system is arranged above the polished wafer 4 to be processed;

[0043] The cleaning system includes an upper integrated bin 10. A lower integrated bin 21 is installed at the bottom of the upper integrated bin 10. A gas distribution bin 9 is installed at the top of the upper integrated bin 10. An N2 intake pipe 7 and an acidic gas intake pipe 8 are connected to the top of the gas distribution bin 9. A high-frequency ultrasonic generator 11 is installed in the middle at the bottom of the upper integrated bin 10. The top of the high-frequency ultrasonic generator 11 passes through the upper integrated bin 10 and is connected to the gas distribution bin 9. The bottom of the high-frequency ultrasonic generator 11 is connected to a main intake cavity 12. A main gas spray head 14 is installed at the bottom of the main intake cavity 12;

[0044] On both inner walls of the lower integrated bin 21, there are high-purity side intake cavities 13. The top end of the high-purity side intake cavity 13 is connected to the gas distribution bin 9. A side gas spray head 15 is installed at the bottom end of the high-purity side intake cavity 13;

[0045] A gas recovery cavity 17 is arranged inside the lower integrated bin 21. The bottom end of the gas recovery cavity 17 is located above the polishing pad 4. The top end of the gas recovery cavity 17 communicates with the upper integrated bin 10. Exhaust pipes 18 are connected to both ends of the upper integrated bin 10. An air extraction port 20 is arranged at the outer end of the exhaust pipe 18.

[0046] In this embodiment, the spraying direction of the side gas spray head 15 is the horizontal direction. A baffle 16 is installed below the side gas spray head 15.

[0047] Specifically, it further includes an integrated locator 5 and a mechanical motion system 6. The cleaning system is driven by the mechanical motion system 6 to move in the XYZ three-axis directions. The integrated locator 5 receives the particle detector or the set particle position information and controls the operation of the mechanical motion system 6;

[0048] Furthermore, the exhaust pipe 18 is of an L-shaped structure. The vertical end of the exhaust pipe 18 passes through the upper integrated bin 10 and communicates with the gas recovery cavity 17. The horizontal end of the exhaust pipe 18 is connected to the air extraction port 20. A dust collection tank 19 is connected to the bottom of the bend of the exhaust pipe 18.

[0049] Furthermore, valves are installed on both the N2 intake pipe 7 and the acidic gas intake pipe 8. A flow regulator is installed on the gas distribution bin 9.

[0050] Further, the distance between the main gas nozzle 14 and the side gas nozzle 15 from the surface of the polishing wafer 4 is 1 - 5 mm; the distance between the bottom end of the gas recovery chamber 17 from the surface of the polishing wafer 4 is 0.5 - 4.5 mm; by controlling the distance between the silicon wafer surface and the cleaning system, the removal efficiency of gas on particles can be effectively controlled. By controlling the distance between the bottom end of the recovery chamber and the silicon wafer surface, it can effectively prevent the particles stripped from the silicon wafer surface from falling back onto the silicon wafer surface again, and can also reduce the overflow of the recovered gas outside the recovery chamber. By controlling the nozzle diameter, the gas flow rate can be controlled to further affect the particle removal effect. The caliber of the main gas nozzle 14 is 0.2 - 0.5 mm.

[0051] Further, the power of the high-frequency ultrasonic generator 11 is 500 - 3000 W, and the frequency is 10 - 40 KHz. On the one hand, high-purity N2 will not introduce new particle contamination, and on the other hand, it can avoid the local surface color difference between the surface and the surrounding caused by the natural oxidation of the silicon wafer surface. The ultra-pure N2 forms microbubbles after passing through the ultrasonic generator. The microbubbles reach the surface of the silicon wafer and the surface particles and burst. The energy of the burst shakes the sub-micron particles on the surface off the silicon wafer surface. The high-purity N2 on the side acts on the contamination through the side air gun. The baffle plate prevents the particles from re-contaminating the silicon wafer after they fall, so as to achieve the effect of removing particles.

[0052] Example 1

[0053] As Figure 2 shown, the present invention also provides a method for removing local large particles on the surface of a polishing wafer, and a device for removing local large particles on the surface of a polishing wafer, including the following steps:

[0054] S1. Place the cleaned polishing wafer 4 in a particle analyzer for detection, and transfer the position information of the sub-micron particles 3 therein to the integrated locator 5;

[0055] S2. Transfer the polishing wafer 4 to be processed to the polishing wafer stage 1 through a manipulator, and fix it on the polishing wafer stage 1 through a vacuum adsorption pipeline 2;

[0056] S3. The integrated locator 5 transfers the particle position information to the mechanical motion system 6. The mechanical motion system 6 drives the cleaning system to perform XYZ three-axis motion, and places the cleaning system above the position of the sub-micron particles 3;

[0057] S4. The high-purity N2 introduced through the intake pipe 7 enters the gas distribution chamber 9 and is divided into two paths. One path forms tiny vibrating bubbles via the high-frequency ultrasonic generator 11. These bubbles pass through the main intake chamber 12 and then reach the main nozzle 14, where they are sprayed onto the surface of the submicron particles 3 and quickly burst, releasing a huge amount of energy. This energy can shake off the submicron particles 3 on the surface of the object. The other path passes through the side intake chamber 13 to the side gas nozzle 15 and acts on the submicron particles 3. The baffle 16 can effectively prevent the fallen contaminants from falling onto the polishing wafer 4 surface again.

[0058] S5. The shaken-off submicron particles 3 then enter the exhaust pipe 18 through the gas recovery chamber 17 by high-purity N2. A dust collection tank 19 is connected to the lower end of the exhaust pipe to prevent the particles from flowing back with the gas. The exhaust pipe 18 is connected to a vacuum pump through the air extraction port 20.

[0059] S6. Keeping the cleaning system and the polishing wafer 4 in place, the high-purity N2 carrying dilute acid vapor enters the gas distribution chamber 9 through the intake pipe 8 and is divided into two paths. One path forms tiny vibrating bubbles via the ultrasonic generator 11. These bubbles pass through the main intake chamber 12 and then reach the main nozzle 14, where they are sprayed onto the local surface of the polishing wafer 4 to be processed and quickly burst, dissolving the metal contaminants into the gas. The other path passes through the side intake chamber 13 to the side gas nozzle 15 and acts on the local surface of the polishing wafer 4. Then the gas enters the exhaust pipe 18 through the gas recovery chamber 17.

[0060] S7. Keeping the cleaning system and the polishing wafer 4 in place, closing the intake pipe 8, after the high-purity N2 enters the gas distribution chamber 9 through the intake port 7, it passes through the side intake chamber 13 to the side gas nozzle 15 and acts on the local surface of the polishing wafer. The above gas enters the exhaust pipe 18 through the gas recovery chamber 17.

[0061] S8. After the cleaning is completed, close all the intake and exhaust pipelines. The integrated locator 5 then transmits a signal to the robotic arm to restore the cleaning system to its initial position, and the processed polishing wafer 4 is inspected and boxed.

[0062] Further, the submicron particles 3 in step S1 are submicron organic matter and dust contaminants re-contaminated during operations such as transfer and inspection after cleaning. The particle size is 0.2 - 10 um, and the number is 1 - 3 particles per wafer. The present invention mainly aims at cleaning silicon wafers re-contaminated with submicron particles after cleaning. This type of particle has the characteristics of limited quantity but usually larger particle size. Targeted local removal of this type of particle can effectively avoid problems such as the deterioration of the surface roughness of the polishing surface and the thinning of the back seal film caused by whole-wafer re-cleaning.

[0063] Further, the polishing wafer is positioned by the reference surface or Notch groove of the polishing wafer during step S2. The vacuum adsorption pressure is -5Kpa to -90KPa, and the diameter of the vacuum adsorption pipeline 2 is 10mm less than the diameter of the polishing wafer 4 to be processed. Through positioning, the large particle information measured by the particle meter can be transmitted to the integrated system of the cleaning system of the present invention. After the integrated system obtains the particle position information, it is positioned through the silicon wafer reference surface or notch groove, which is conducive to the accurate transmission of particle information. The diameter of the vacuum adsorption pipeline is slightly smaller than the diameter of the silicon wafer. On the one hand, it is conducive to the adsorption of the silicon wafer, and on the other hand, it will not cause the deformation of the silicon wafer due to excessive suction force.

[0064] The N2 in step S4 is high-purity N2, and the flow rate is 5 - 50ml / s; the dilute acid in step S6 is HCl or HF, and its concentration is 0.05% - 0.1%. It is generated by carrying N2 into the acid solution of HCl or HF configured. The pumping rate of the air pump in steps S5, S6, and S7 is 10 - 80ml / s. Through the suction force of the external air pump, the incoming high-purity N2 returns to the exhaust pipeline along the recovery chamber. The high-purity nitrogen purging process fills the silicon wafer surface with passivating N2, reduces the contact between the silicon wafer and O2, and at the same time avoids the risk of possible contamination during the equipment operation, keeping the silicon wafer surface clean. Through the suction force of the external air pump, the incoming gas returns to the exhaust pipeline 18 along the gas recovery chamber 17, which can further prevent particles from overflowing out of the gas recovery chamber 17 with the gas. The high-purity N2 carrying the dilute acid vapor entering the pipeline will not introduce new particle contamination. The dilute acid can effectively remove metal contamination through chemical reactions. The high-purity N2 carrying the dilute acid vapor forms tiny vibrating bubbles through the ultrasonic generator. The tiny bubbles rapidly rupture on the surface of the main nozzle silicon wafer, and the rupture energy integrates the metal contamination into the gas, which is purged by the high-purity N2 carrying the dilute acid vapor through the side nozzle and enters the exhaust pipeline with the gas recovery gun, avoiding the leakage of acid gas and achieving the effect of effectively eliminating metal contamination.

[0065] Example 2

[0066] As Figure 3 shown, the present invention also provides a method for removing local large particles on the surface of a polishing wafer and a device for removing local large particles on the surface of a polishing wafer. The specific operation steps are as follows:

[0067] S1. Place the cleaned polishing wafer 4 in a particle meter for detection, and transmit the particle position information of 1 - 2 contaminated particles to the positioning integrated system, with a particle size of ≥1um and ≤10um;

[0068] S2. Transfer the polishing wafer 4 to be processed to the polishing wafer stage 1 through a manipulator. After positioning by the positioning edge or notch groove, it is fixed on the polishing wafer stage through a vacuum adsorption pipeline with a diameter less than 10 mm of the polishing wafer to be processed, and the vacuum adsorption pressure is -20 to -40 KPa.

[0069] S3. The integrated positioning system transmits the particle position information to the mechanical motion system. The mechanical motion system carries the cleaning system for X-Y-Z directional movement and places the cleaning system at a specific position. The cleaning system is 3.2 - 4.2 mm away from the polishing wafer, and the distance from the bottom end of the gas recovery chamber to the surface of the polishing wafer is 3.4 - 4.4 mm.

[0070] S4. High-purity N2 with a flow rate of 12 - 24 ml / s introduced through the intake pipeline enters the gas distribution chamber and is divided into two paths. One path forms tiny vibrating bubbles through an ultrasonic generator with a power of 1200 - 1600 W and a frequency of 15 - 20 KHz. These bubbles pass through the main intake chamber and are sprayed onto the solid contamination surface through the main nozzle with a diameter of 0.36 - 0.42 mm and then quickly burst, releasing a huge amount of energy. This energy can shake off the solid contamination on the object surface. The other path passes through the side intake chamber to the side nozzle with a diameter of 0.36 - 0.42 mm and acts on the contamination. The baffle can effectively prevent the fallen contamination from falling onto the polishing wafer surface again.

[0071] S5. The shaken-off solid contamination then enters the exhaust pipeline through high-purity N2 via the gas recovery chamber. A dust collection tank is connected to the lower end of the exhaust pipeline to prevent particles from flowing back with the gas. The exhaust pipeline is connected to a vacuum pump through an air extraction port, and its pumping rate is 15 - 25 ml / s.

[0072] S6. Keep the cleaning system and the polishing wafer in place. High-purity N2 carrying dilute acid vapor with a concentration of 0.08% - 0.1% enters the gas distribution chamber through the intake pipeline and is divided into two paths. One path forms tiny vibrating bubbles through an ultrasonic generator with a power of 800 - 1200 W and a frequency of 10 - 18 KHz. These bubbles pass through the main intake chamber and are sprayed onto the local surface of the polishing wafer to be processed through the main nozzle and quickly burst, dissolving the metal contamination into the gas. The other path passes through the side intake chamber to the side nozzle and acts on the local surface of the polishing wafer. The above gas enters the exhaust pipeline through the gas recovery chamber, and the pumping rate is 25 - 50 ml / s.

[0073] S7. Keep the cleaning system and the polishing wafer in place. Close the dilute acid intake pipeline. High-purity N2 enters the gas distribution chamber through the air intake port and then passes through the side intake chamber to the side nozzle and acts on the local surface of the polishing wafer. The above gas enters the exhaust pipeline through the gas recovery chamber, and the pumping rate is 28 - 36 ml / s.

[0074] Example 3

[0075] As Figure 4 shown, the present invention also provides a method for removing local large particles on the surface of a polishing wafer and a device for removing local large particles on the surface of a polishing wafer. The specific operation steps are as follows:

[0076] S1. Place the cleaned polishing wafer in a particle analyzer for detection, and transfer the position information of the particles contaminated with 2 - 3 particles to the positioning integration system. The particle size is ≥0.2um and <1um;

[0077] S2. Transfer the polishing wafer to be processed to the polishing wafer stage by a manipulator. After positioning through the positioning edge or notch groove, it is fixed on the stage by a vacuum adsorption pipe with a diameter 10mm smaller than the polishing wafer to be processed. The vacuum adsorption pressure is -45 to -65KPa;

[0078] S3. The integrated positioning system transfers the particle position information to the mechanical motion system. The mechanical motion system carries the cleaning system for X - Y - Z directional movement and places the cleaning system at a specific position. The cleaning system is 1.6 - 2.2mm away from the polishing wafer, and the distance from the bottom end of the recovery chamber to the surface of the polishing wafer is 1.8 - 2.4mm;

[0079] S4. High - purity N2 with a flow rate of 32 - 40ml / s introduced through the intake pipe enters the gas distribution chamber and is divided into two paths. One path forms tiny vibrating bubbles through an ultrasonic generator with a power of 1800 - 2400W and a frequency of 24 - 34KHz. These bubbles reach the main nozzle through the main intake chamber and are sprayed onto the solid contamination surface at 0.28 - 0.32mm and then quickly burst and release a huge amount of energy. This energy can shake off the solid contamination on the object surface; the other path reaches the side nozzle through the side intake chamber and acts on the contamination. The baffle can effectively prevent the fallen contamination from falling onto the polishing wafer surface again;

[0080] S5. The shaken - off solid contamination then enters the exhaust pipe through the high - purity N2 via the gas recovery chamber. A dust collection tank is connected to the lower end of the exhaust pipe to prevent particles from flowing back with the gas. The exhaust pipe is connected to a vacuum pump through an air extraction port, and its pumping rate is 35 - 42ml / s;

[0081] S6. Keep the cleaning system and the polishing wafer in place. High-purity N2 carrying dilute acid vapor with a concentration of 0.08% - 0.1% enters the gas distribution chamber through the intake pipe and is divided into two paths. One path forms tiny vibrating bubbles through an ultrasonic generator with a power of 1600 - 2000W and a frequency of 20 - 26KHz. These bubbles pass through the main intake chamber and then are sprayed onto the local surface of the polishing wafer to be processed by the main nozzle and quickly burst, dissolving the metal contamination into the gas. The other path passes through the side intake chamber to the side nozzle and acts on the local surface of the polishing wafer. The above gas enters the exhaust pipe through the gas recovery chamber, and the pumping rate is 36 - 55 ml / s.

[0082] S7. Keep the cleaning system and the polishing wafer in place and close the intake pipe. High-purity N2 enters the gas distribution chamber through the intake port and then passes through the side intake chamber to the side nozzle and acts on the local surface of the polishing wafer. The above gas enters the exhaust pipe through the gas recovery chamber, and the pumping rate is 40 - 50 ml / s.

[0083] As Figures 5-8 shown, the sub-micron particles 3 attached to the surface of the polishing wafer 4 can generally be divided into two adsorption methods. One is the physical adsorption force F1, and the other is the chemical adsorption F2. Physical adsorption means that the sub-micron particles 3 are attached to the surface of the polishing wafer 4 through van der Waals forces (intermolecular forces) and electronic forces. The chemical adsorption force F2 refers to the attachment of the sub-micron particles 3 to the clean and flat surface of the polishing wafer 4 through chemical bonds 22. Sub-micron particles 3 are generally present in the clothing, environment, various equipment, and materials used by personnel in the clean room, and will attach to the surface during the cleaning, storage, and handling of the polishing wafer 4.

[0084] For the particles attached through physical adsorption F1 and chemical adsorption force F2, the main nozzle forms a nitrogen gas flow carrying micro-bubbles 23 with high-purity nitrogen gas through an ultrasonic generator. The micro-bubbles carried in it burst instantaneously when reaching near the surface of the polishing wafer 4 and the surface of the sub-micron particles 3. The instantaneous burst releases huge energy in all directions, shaking off the sub-micron particles 3 on the surface. The high-speed gas flow blown out by the side nozzle will exert a blowing force F3 on the sub-micron particles 3 on the surface to promote the detachment of the sub-micron particles 3 from the surface of the polishing wafer 4, thus achieving the effect of removing the sub-micron particles 3. By controlling the distance between the surface of the polishing wafer 4 and the nozzle, the removal efficiency of the gas on the sub-micron particles 3 can be effectively controlled. By controlling the nozzle diameter, the size of the gas flow can be controlled to further affect the removal effect of the sub-micron particles 3.

[0085] By controlling the distance between the bottom end of the gas recovery chamber and the surface of the polishing wafer 4, it is possible to effectively prevent the particles peeled off from the surface of the polishing wafer 4 from falling onto the surface of the polishing wafer 4 again, and it is also possible to avoid the overflow of the recovered gas outside the recovery chamber. After the submicron particles 3 are detached from the surface, in order to prevent them from adhering to the surface of the polishing wafer 4 again, a suction force F4 is generated by using a suction pump to take the detached submicron particles 3 along with the gas into the exhaust pipe through the recovery chamber, so as to ensure that the submicron particles 3 that have been detached from the surface will not cause secondary adhesion. Subsequently, the N2 carrying dilute acid vapor dissolves the metal contamination brought by the particles into the gas and discharges it through the exhaust pipe to further purify the surface of the polishing wafer 4.

[0086] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for removing local large particles on the surface of a polishing sheet, comprising a dry cleaning device, characterized in that: The dry cleaning device comprises a polishing sheet carrier (1), a vacuum adsorption pipe (2) is arranged inside the polishing sheet carrier (1), a polishing sheet (4) to be processed is installed on the top of the polishing sheet carrier (1), and the surface of the polishing sheet (4) has submicron particles (3); a cleaning system is arranged on the upper part of the polishing sheet (4) to be processed; The cleaning system comprises an upper integrated chamber (10), a lower integrated chamber (21) is installed at the bottom of the upper integrated chamber (10), a gas diversion chamber (9) is installed at the top of the upper integrated chamber (10), the top of the gas diversion chamber (9) is connected to an N2 gas inlet pipeline (7) and an acid gas gas inlet pipeline (8), a high-frequency ultrasonic generator (11) is installed in the middle of the bottom of the upper integrated chamber (10), the top of the high-frequency ultrasonic generator (11) passes through the upper integrated chamber (10) and is connected to the gas diversion chamber (9), the bottom of the high-frequency ultrasonic generator (11) is connected to a main gas inlet chamber (12), and the bottom of the main gas inlet chamber (12) is installed with a main gas nozzle (14); The inner walls on both sides of the lower integrated chamber (21) are provided with high-purity side air inlet cavities (13), the top of the high-purity side air inlet cavity (13) is connected to the gas diversion chamber (9), and the bottom of the high-purity side air inlet cavity (13) is installed with a side gas nozzle (15); A gas recovery chamber (17) is provided inside the lower integrated chamber (21), the bottom end of the gas recovery chamber (17) is located above the polishing sheet (4), the top end of the gas recovery chamber (17) is connected to the upper integrated chamber (10), both ends of the upper integrated chamber (10) are connected to an exhaust pipe (18), and an exhaust port (20) is provided at the outer end of the exhaust pipe (18).

2. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: The spraying direction of the side gas nozzle (15) is horizontal, and a baffle (16) is installed at the bottom of the side gas nozzle (15).

3. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: It also includes an integrated positioner (5) and a mechanical motion system (6). The cleaning system is driven by the mechanical motion system (6) to move in the three-axis directions of X, Y and Z. The integrated positioner (5) receives information on the particle detector or the set particle position and controls the operation of the mechanical motion system (6).

4. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: The exhaust pipe (18) is an L-shaped structure, the vertical end of the exhaust pipe (18) passes through the upper integrated bin (10) and is connected to the gas recovery chamber (17), the horizontal end of the exhaust pipe (18) is connected to the air suction port (20), and the bent bottom of the exhaust pipe (18) is connected to a dust collecting tank (19).

5. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: Valves are installed on the N2 inlet pipeline (7) and the acid gas inlet pipeline (8), and a flow regulator is installed on the gas diversion chamber (9).

6. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: The distance between the main gas nozzle (14) and the side gas nozzle (15) and the surface of the polishing sheet (4) is 1-5 mm; the distance between the bottom end of the gas recovery chamber (17) and the surface of the polishing sheet (4) is 0.5-4.5 mm; the caliber of the main gas nozzle (14) is 0.2-0.5 mm.

7. The device for removing local large particles on the surface of a polishing sheet according to claim 1, characterized in that: The power of the high-frequency ultrasonic generator (11) is 500-3000W, and the frequency is 10-40KHz.

8. A method for removing local large particles on the surface of a polishing pad, used in the device for removing local large particles on the surface of a polishing pad as claimed in any one of claims 1 to 7, characterized in that: The steps include: S1, placing the clean polishing sheet (4) on a particle analyzer for detection, and transmitting the position information of the submicron particles (3) therein to an integrated locator (5); S2, transferring the polishing sheet (4) to be processed to the polishing sheet carrier (1) through a robot arm, and fixing it on the polishing sheet carrier (1) through a vacuum adsorption pipe (2); S3, the integrated positioner (5) transmits the particle position information to the mechanical motion system (6), the mechanical motion system (6) carries the cleaning system to perform XYZ three-axis motion, and places the cleaning system above the position of the submicron particle (3); S4, high-purity N2 introduced through the air inlet pipe (7) enters the gas diversion chamber (9) and is divided into two paths. One path is formed into tiny bubbles with vibrations through the high-frequency ultrasonic generator (11). These bubbles are sprayed onto the surface of the submicron particles (3) through the main air inlet cavity (12) and then to the main nozzle (14). They burst rapidly and release huge energy. This energy can shake off the submicron particles (3) on the surface of the object. The other path is passed through the side air inlet cavity (13) to the side gas nozzle (15) and acts on the submicron particles (3). The baffle (16) can effectively prevent the fallen contaminants from falling onto the surface of the polishing sheet (4) again. S5, the submicron particles (3) that have been shaken off then enter the exhaust pipe (18) through the high-purity N2 via the gas recovery chamber (17), the lower end of the exhaust pipe is connected to a dust collecting tank (19) to prevent the particles from flowing back with the gas, and the exhaust pipe (18) is connected to a vacuum pump via a gas extraction port (20); S6. The cleaning system and the polishing sheet (4) are kept in place. The high-purity N2 carrying the dilute acid vapor enters the gas diversion chamber (9) through the air intake pipe (8) and is divided into two paths. One path is formed by the ultrasonic generator (11) to form tiny bubbles with vibration. These bubbles pass through the main air intake chamber (12) and then to the main nozzle (14) to be sprayed onto the local surface of the polishing sheet (4) to be treated and quickly break up to dissolve the metal contamination into the gas; the other path passes through the side air intake chamber (13) to the side gas nozzle (15) and acts on the local surface of the polishing sheet (4); then the gas passes through the gas recovery chamber (17) and enters the exhaust pipe (18). S7. Keep the cleaning system and the polishing sheet (4) in place, close the air inlet pipe (8), and allow the high-purity N2 to enter the gas diversion chamber (9) through the air inlet (7), then pass through the side air inlet chamber (13) to the side gas nozzle (15) and act on the local surface of the polishing sheet; the above gas enters the exhaust pipe (18) through the gas recovery chamber (17). S8. After the cleaning is completed, all air inlet and exhaust pipes are closed, and the integrated positioner (5) transmits a signal to the robot arm to restore the cleaning system to the initial position, and the processed polishing sheet (4) is inspected and boxed.

9. The method for removing local large particles on the surface of a polishing sheet according to claim 8, characterized in that: The submicron particles (3) in step S1 are submicron organic matter and dust contaminated during the transfer and inspection process after cleaning, with a particle size of 0.2-10 um and a number of 1-3 particles per piece.

10. The method for removing local large particles on the surface of a polishing sheet according to claim 8, characterized in that: The polishing sheet in step S2 is positioned by a reference surface or a Notch groove of the polishing sheet, the vacuum adsorption pressure is -5KPa to -90KPa, and the diameter of the vacuum adsorption pipeline (2) is 10mm smaller than the diameter of the polishing sheet (4) to be processed; the N2 in step S4 is high-purity N2, and the flow rate is 5-50ml / s; the dilute acid in step S6 is HCl or HF, and its concentration is 0.05%-0.1%, which is produced by passing N2 into a configured HCl or HF acid solution and carrying it; the exhaust rate of the exhaust pump in steps S5, S6, and S7 is 10-80ml / s.

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