Automatic grinding fluid mixing and supplying system

Abstract

The invention relates to an automatic mixing and supplying system for grinding fluid. The system comprises a mixing mechanism, a supplying mechanism, a wet nitrogen generating mechanism and a PLC control system. The mixing mechanism is provided with a mixing barrel, a mixing pump arranged at the bottom of the mixing barrel and at least two stirring nozzles arranged in the mixing barrel, and the stirring nozzles are matched with the mixing pump to circularly mix the grinding stock solution and the ultrapure water. The supply mechanism is provided with a supply barrel connected with the output end of the mixing pump and a supply pump arranged at the bottom of the supply barrel and used for supplying the grinding liquid to the client side. The wet nitrogen generating mechanism is provided with a generating tank, a wet nitrogen generator arranged in the generating tank and a generating joint which is connected with the wet nitrogen generator and is used for introducing ultrapure water and high-purity nitrogen, and a nitrogen filter is arranged at the generating joint; an outlet of the generation tank is respectively connected with inlets of the mixing barrel and the supply barrel and is provided with a flow meter and a pressure sensor which are used for monitoring the output flow and the output pressure of wet nitrogen generated by the generation tank.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to an automatic mixing and supplying system for a grinding liquid. Background Art

[0002] Chemical mechanical polishing (CMP) is an important process step in the manufacturing of integrated circuits (ICs). CMP uses the physical and chemical effects of slurry to perform micro-cutting on the surface of silicon wafers. Slurry is also called chemical mechanical polishing. Its principle is a processing technology that combines chemical corrosion and mechanical removal. It is the only technology in mechanical processing that can achieve global surface flatness.

[0003] Existing equipment for mixing and supplying grinding liquid all uses manual and semi-automatic mechanical stirring to mix the grinding liquid. However, manual participation in the mixing of grinding liquid is costly, and stability and safety cannot be guaranteed. In addition, mechanical stirring has a cutting effect on the molecular components of the grinding liquid in the grinding liquid, which will affect the performance of the grinding liquid and cause grinding failure. At the same time, the traditional mixing method requires manual participation, and the mixing environment is generally semi-open, resulting in low cleanliness of the mixing environment and easy contamination of the grinding liquid.

[0004] At the same time, the grinding fluid must not produce crystallization, precipitation, flocculation, stratification and other problems during pre-mixing and use, so wet nitrogen needs to be introduced into the supply system to eliminate the risk of crystallization of the grinding fluid. However, most of the traditional wet nitrogen generation is not filtered and flow controlled, and is generally generated through a simple pipeline through liquid. Except for the humidity meeting the standard, other properties cannot meet the requirements. In addition, this kind of wet nitrogen passing into the grinding fluid has a high risk of contamination, which directly affects the supply demand and quality of the grinding fluid. Summary of the invention

[0005] The purpose of the present invention is to provide an automatic mixing and supply system for grinding liquid, which can ensure a closed environment for mixing and supplying to ensure cleanliness and avoid pollution risks by setting up a closed mixing barrel and a supply barrel, and a stirring nozzle is set in the mixing barrel to cooperate with a mixing pump to form an irregular flow field in the barrel in a jet manner, so as to circulate and mix the grinding stock solution and ultrapure water without destroying the performance of the grinding liquid; by setting a nitrogen filter, a flow meter and a pressure sensor in a wet nitrogen generating mechanism, and cooperating with a PLC control system to control the purity of high-purity nitrogen, the output flow rate and output pressure of the wet nitrogen generated by the generating tank, it is ensured that the wet nitrogen meets the grinding liquid mixing use standard.

[0006] To achieve the above object, the present invention provides an automatic mixing and supplying system for abrasive liquid, comprising:

[0007] A mixing mechanism, comprising a mixing barrel, a mixing pump disposed at the bottom of the mixing barrel, and at least two stirring nozzles disposed in the mixing barrel, wherein the stirring nozzles cooperate with the mixing pump to circulate and mix the grinding stock solution and ultrapure water in the mixing barrel;

[0008] A supply mechanism, provided with a supply barrel connected to the output end of the mixing pump, and a supply pump provided at the bottom of the supply barrel and used for supplying the grinding liquid to the client;

[0009] A wet nitrogen generating mechanism is provided with a generating tank, a wet nitrogen generator arranged in the generating tank, and a generating joint connected to the wet nitrogen generator and used to access ultrapure water and high-purity nitrogen, wherein a nitrogen filter is provided at the generating joint, the generating tank outlet is respectively connected to the mixing barrel and the supply barrel inlet, and the generating tank outlet is provided with a flow meter and a pressure sensor, and the flow meter and the pressure sensor cooperate to control the output flow and output pressure of the wet nitrogen generated by the generating tank;

[0010] A PLC control system is connected to the mixing mechanism, the supply mechanism and the wet nitrogen generating mechanism, and is used to monitor the automatic operation of the grinding liquid automatic mixing and supply system.

[0011] Optionally, a circulation branch is provided at the output end of the mixing pump, and the circulation branch extends into the mixing barrel and is respectively connected to at least two of the stirring nozzles.

[0012] Optionally, at least two of the stirring nozzles are evenly distributed in the mixing barrel along the circumferential direction and staggeredly distributed vertically.

[0013] Optionally, the mixing pump and the supply pump are magnetic levitation pumps.

[0014] Optionally, a vortex breaker is provided on the inner side of the bottom of the mixing barrel, and the vortex breaker is connected to the input end of the mixing pump.

[0015] Optionally, rotatable cleaning nozzles are provided in the mixing barrel and the supply barrel, and the cleaning nozzles are externally connected to an ultrapure water cleaning source, a high-purity nitrogen pressure source, and a potassium hydroxide cleaning source.

[0016] Optionally, the mixing barrel is provided with an electronic scale connected to the PLC control system, and the electronic scale is used to cooperate with the PLC control system to control the precise quantitative input of grinding stock solution and ultrapure water to ensure the accuracy of the grinding solution mixing ratio.

[0017] Optionally, output ends of the mixing pump and the supply pump are provided with measuring instruments, and the measuring instruments are used to measure parameters of the output grinding fluid.

[0018] Optionally, the mixing barrel and the supply barrel are respectively provided with a plurality of liquid level sensors for monitoring the liquid level in the barrels, and the mixing pump and the supply pump are provided with leakage sensors for monitoring pump body leakage.

[0019] The beneficial effects of the present invention are as follows: by setting a closed mixing barrel and a supply barrel, a closed environment for mixed supply is ensured to ensure cleanliness and avoid pollution risks, and a stirring nozzle is set in the mixing barrel to cooperate with a mixing pump to form an irregular flow field in the barrel in a jet manner, so that the grinding stock solution and ultrapure water are circulated and mixed without destroying the performance of the grinding liquid; by setting a nitrogen filter, a flow meter and a pressure sensor in the wet nitrogen generating mechanism, and cooperating with a PLC control system to control the purity of high-purity nitrogen, the output flow rate and output pressure of the wet nitrogen generated by the generating tank, it is ensured that the wet nitrogen meets the grinding liquid mixing use standard.

[0020] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of an automatic mixing and supplying system for abrasive liquid according to an embodiment of the present invention;

[0022] Figure 2 A schematic structural diagram of a mixing mechanism of an automatic mixing and supplying system according to an embodiment of the present invention;

[0023] Figure 3 A schematic structural diagram of a supply mechanism of an automatic mixing supply system according to an embodiment of the present invention;

[0024] Figure 4 It is a schematic structural diagram of a wet nitrogen generating mechanism of an automatic mixing and supplying system shown in one embodiment of the present invention;

[0025] In the figure: 1. mixing mechanism; 11. mixing barrel; 12. mixing pump; 13. stirring nozzle; 2. supply mechanism; 21. supply barrel; 22. supply pump; 3. wet nitrogen generating mechanism; 31. generating tank; 32. wet nitrogen generator; 33. generating joint; 34. pressure sensor; 4. PLC control system; 5. circulation branch; 6. cleaning nozzle; 7. electronic scale; 71. electronic scale head; 8. measuring instrument; 9. liquid level sensor; 10. leakage sensor. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] See also Figures 1 to 4The automatic mixing and supplying system of the grinding liquid shown in a preferred embodiment of the present application comprises a mixing mechanism 1, a supply mechanism 2, a wet nitrogen generating mechanism 3 and a PLC control system 4. The mixing mechanism 1 is provided with a mixing barrel 11, a mixing pump 12 arranged at the bottom of the mixing barrel 11 and at least two stirring nozzles 13 arranged in the mixing barrel 11, and the stirring nozzles 13 cooperate with the mixing pump 12 to circulate and mix the grinding stock solution and ultrapure water in the mixing barrel 11. The supply mechanism 2 is provided with a supply barrel 21 connected to the output end of the mixing pump 12, and a supply pump 22 arranged at the bottom of the supply barrel 21 and used to supply the grinding liquid to the client. The wet nitrogen generating mechanism 3 is provided with a generating tank 31, a wet nitrogen generator 32 arranged in the generating tank 31, and a generating joint 33 connected to the wet nitrogen generator 32 and used to access ultrapure water and high-purity nitrogen. A nitrogen filter is provided at the generating joint 33. The outlet of the generating tank 31 is respectively connected to the inlet of the mixing barrel 11 and the supply barrel 21, and a flow meter and a pressure sensor 34 are provided at the outlet of the generating tank 31. The flow meter and the pressure sensor 34 cooperate to monitor the output flow and output pressure of the wet nitrogen generated by the generating tank 31. The PLC control system 4 is connected to the mixing mechanism 1, the supply mechanism 2 and the wet nitrogen generating mechanism 3, and is used to control the automatic operation of the grinding liquid automatic mixing and supply system.

[0030] According to the scheme of the embodiment of the present invention, by setting up a closed mixing barrel 11 and a supply barrel 21, a closed environment for mixed supply is ensured to ensure cleanliness and avoid contamination risks, and a stirring nozzle 13 is set in the mixing barrel 11 to cooperate with the mixing pump 12 to form an irregular flow field in the barrel in a jet manner, so that the grinding stock solution and ultrapure water are circulated and mixed without destroying the performance of the grinding liquid; by setting a nitrogen filter, a flow meter and a pressure sensor 34 in the wet nitrogen generating mechanism 3, and cooperating with the PLC control system 4 to control the purity of high-purity nitrogen, the output flow rate and output pressure of the wet nitrogen generated by the generating tank 31, it is ensured that the wet nitrogen meets the grinding liquid mixed use standard. It should be noted here that the configuration of the mixing mechanism 1 and the supply mechanism 2 is the same. The purpose of setting up the supply mechanism 2 separately is to enable the mixing mechanism 1 to continue to mix the eye mask stock solution and the ultrapure water when the client input is blocked and suspended, and the supply mechanism 2 can stir the mixed grinding liquid to maintain the state of the grinding liquid to avoid crystallization.

[0031] The following is a detailed description with specific embodiments:

[0032] See also Figure 2, a circulation branch 5 is provided at the output end of the mixing pump 12, and the circulation branch 5 extends into the mixing barrel 11 and is respectively connected to at least two stirring nozzles 13. At least two stirring nozzles 13 are evenly distributed along the circumference in the mixing barrel 11 and staggered along the vertical direction. In the present embodiment, there are two stirring nozzles 13 provided in the mixing barrel 11, and the two stirring nozzles 13 are horizontally arranged along the vertical plane in the mixing barrel 11 at a clockwise 180° offset, and the stirring nozzles 13 are arranged at a 60° installation angle (the installation angle refers to the angle between the horizontal line at the end of the stirring nozzle 13 perpendicular to the central axis of the mixing barrel 11 and the central axis of the stirring nozzle 13). The circulation branch 5 is a PFA pipeline. Further, in the present embodiment, the connecting pipelines involved are all PFA pipelines to ensure the cleanliness of the grinding liquid transportation. After the mixing pump 12 sucks the solution in the mixing barrel 11, the solution returns to the mixing barrel 11 through the circulation branch 5 and is sprayed out through the stirring nozzle 13. The two stirring nozzles 13 are arranged to be installed clockwise and can drive the solution at the bottom of the mixing barrel 11 to roll and circulate, thereby achieving the mixing function. At the same time, the two stirring nozzles 13 maintain an installation angle of 60°, which can ensure that the flow direction of the solution will collide with the circulation loop at the bottom of the barrel, so as to achieve a more uniform and lasting mixing flow field so that the grinding stock solution and ultrapure water are evenly mixed. Specifically, the stirring nozzle 13 is machined from polytetrafluoroethylene (PTFE) rods to ensure that no metal ions are precipitated.

[0033] See also Figure 4 In this embodiment, the wet nitrogen generator 32 is manufactured by PTFE one-piece molding process, and the internal design has dense micro-holes to ensure the density of the bubbles. At the same time, it is combined with a PFA pneumatic valve, and the opening of the valve is automatically controlled by the PLC control system 4. In addition, a nitrogen filter is provided to provide the wet nitrogen system with a purity of 99.9999% high-purity nitrogen. The nitrogen and ultrapure water after purging at a nitrogen pressure of 0.1Mpa-0.3Mpa are mixed into a micro-mist "water mist". By using a hygrometer to measure, the humidity can reach 98% RH, which can fully meet the grinding liquid's demand for nitrogen humidification.

[0034] In this embodiment, the mixing barrel 11 and the supply barrel 21 are made of HDPE material through an integrated molding process, and the barrel interface and the barrel cover supporting connection device are processed and customized accordingly. The barrel body is sealed by an interference seal ring and a threaded connection to form a closed environment, which ensures the cleanliness of the grinding liquid mixing environment. At the same time, an observation window is set on the barrel cover, which can intuitively understand the mixing state of the grinding liquid in the barrel, and consider the safety of the operator to a greater extent. At the same time, the supply system is designed to add a sampling interface on the barrel body, which can sample and analyze the grinding liquid while conveying the grinding liquid, ensuring the quality of each batch of grinding liquid supplied.

[0035] The mixing pump 12 and the supply pump 22 are magnetic suspension pumps. A vortex breaker is provided on the inner side of the bottom of the mixing barrel 11, and the vortex breaker is connected to the input end of the mixing pump 12. Similarly, a vortex breaker is provided on the inner side of the bottom of the supply barrel 21, and the vortex breaker is connected to the input end of the supply pump 22. The vortex breaker can not only play the function of vortex destruction when the pump is pumping liquid, but also can satisfy the bottom circulation of the barrel when the pump is pumping liquid.

[0036] See also Figure 2 and Figure 3 A rotatable cleaning nozzle 6 is provided in the mixing barrel 11 and the supply barrel 21. The cleaning nozzle 6 is externally connected to an ultrapure water cleaning source, a high-purity nitrogen pressure source, and a potassium hydroxide cleaning source. Under the combined effect of water and gas pressure, the mixing barrel 11 and the supply barrel 21 are automatically cleaned and purged through the PLC control system 4 to improve the quality of the grinding liquid supply. The high-purity polytetrafluoroethylene (PTFE) rod used in the cleaning nozzle 6 is processed by a one-time molding method of a 6-axis high-precision machine tool. The cleaning nozzle 6 is divided into two parts: a rotating device and a connecting device. The rotating device is designed with a regular 360° hole with a diameter of 0.8mm. It can rotate under a micro-pressure condition through an interference fit, so that ultrapure water can be thrown out with a pressure of 1Kg to achieve a cleaning effect inside the barrel.

[0037] See also Figure 2 The mixing barrel 11 is provided with an electronic scale 7 connected to the PLC control system 4. The electronic scale 7 is used to cooperate with the PLC control system 4 to control the precise quantitative input of the grinding stock solution and ultrapure water to ensure the accuracy of the grinding liquid mixing ratio. In this embodiment, the electronic scale is coated with a polypropylene PP plate to prevent corrosion of the grinding liquid and gas. At the same time, an electronic scale head 71 is installed to connect to the PLC control system 4 to monitor the amount of grinding stock solution and ultrapure water in the mixing process and the condition of the grinding residual liquid in the supply process in real time to ensure the reliability of the grinding liquid mixing.

[0038] See also Figure 2 and Figure 3 The output ends of the mixing pump 12 and the supply pump 22 are provided with a measuring instrument 8, which is used to measure the parameters of the outputted grinding liquid. In this embodiment, the measuring instrument 8 measures various parameters of the grinding liquid, such as specific gravity, conductivity, pH value, temperature, concentration and other parameters, to ensure the supply quality of the grinding liquid.

[0039] See also Figure 2 and Figure 3, the mixing barrel 11 and the supply barrel 21 are respectively provided with a number of liquid level sensors 9 for monitoring the liquid level in the barrel, and the mixing pump 12 and the supply pump 22 are provided with leakage sensors 10 for monitoring the leakage of the pump body. The leakage sensor 10 can ensure the monitoring of the pump operation process. If any leakage accident occurs, the operation and emergency disposal of the pump can be controlled in time, which can ensure the safe and stable operation of the system. The installation of the liquid level sensor 9 can ensure that the liquid level in the barrel will not exceed the high level or even overflow when the electronic scale 7 fails. At the same time, the installation of the liquid level sensor 9 at the bottom of the barrel to monitor the liquid level in the barrel can ensure that there is no risk of idling of the pump. At the same time, with the cooperation of the electronic scale 7 and the PLC control system 4, the residual grinding liquid in the mixing barrel 11 and the supply barrel 21 can be reduced as much as possible.

[0040] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. Automatic mixing and supply system for grinding liquid, characterized in that: include: A mixing mechanism, comprising a mixing barrel, a mixing pump disposed at the bottom of the mixing barrel, and at least two stirring nozzles disposed in the mixing barrel, wherein the stirring nozzles cooperate with the mixing pump to circulate and mix the grinding stock solution and ultrapure water in the mixing barrel; A supply mechanism, provided with a supply barrel connected to the output end of the mixing pump, and a supply pump provided at the bottom of the supply barrel and used for supplying the grinding liquid to the client; A wet nitrogen generating mechanism is provided with a generating tank, a wet nitrogen generator arranged in the generating tank, and a generating joint connected to the wet nitrogen generator and used to access ultrapure water and high-purity nitrogen, wherein a nitrogen filter is provided at the generating joint, the generating tank outlet is respectively connected to the mixing barrel and the supply barrel inlet, and the generating tank outlet is provided with a flow meter and a pressure sensor, wherein the flow meter and the pressure sensor cooperate to monitor the output flow and output pressure of the wet nitrogen generated by the generating tank; A PLC control system is connected to the mixing mechanism, the supply mechanism and the wet nitrogen generating mechanism, and is used to control the automatic operation of the grinding liquid automatic mixing and supply system.

2. The automatic mixing and supplying system for grinding liquid according to claim 1, characterized in that: The output end of the mixing pump is provided with a circulation branch, which extends into the mixing barrel and is respectively connected to at least two of the stirring nozzles.

3. The automatic mixing and supplying system for grinding liquid according to claim 2, characterized in that: At least two of the stirring nozzles are evenly distributed in the mixing barrel along the circumferential direction and staggeredly distributed along the vertical direction.

4. The automatic mixing and supplying system for grinding liquid according to claim 1, characterized in that: The mixing pump and the supply pump are magnetic levitation pumps.

5. The automatic mixing and supplying system for grinding liquid according to claim 4, characterized in that: A vortex breaker is arranged on the inner side of the bottom of the mixing barrel, and the vortex breaker is connected to the input end of the mixing pump.

6. The automatic mixing and supplying system for grinding liquid according to claim 1, characterized in that: Rotatable cleaning nozzles are arranged in the mixing barrel and the supply barrel, and the cleaning nozzles are externally connected to an ultrapure water cleaning source, a high-purity nitrogen pressure source and a potassium hydroxide cleaning source.

7. The automatic mixing and supplying system for grinding liquid according to claim 6, characterized in that: The mixing barrel is provided with an electronic scale connected to the PLC control system, and the electronic scale is used to cooperate with the PLC control system to control the precise quantitative input of grinding stock solution and ultrapure water to ensure the accuracy of the grinding solution mixing ratio.

8. The automatic mixing and supplying system for grinding liquid according to claim 1, characterized in that: The output ends of the mixing pump and the supply pump are provided with measuring instruments, which are used to measure parameters of the outputted grinding fluid.

9. The automatic mixing and supplying system for grinding liquid according to claim 1, characterized in that: The mixing barrel and the supply barrel are respectively provided with a plurality of liquid level sensors for monitoring the liquid level in the barrels, and the mixing pump and the supply pump are provided with leakage sensors for monitoring the leakage of the pump body.

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