Combined filtering system for simultaneously filtering silicon slag by multiple devices and treatment method

Abstract

The invention discloses a combined filtering system for simultaneously filtering silicon slag by multiple devices and a treatment method. The combined filtering system comprises a plurality of machine tool dirty liquid tanks, a centralized water tank, a centrifugal machine and a bag machine, each machine tool dirty liquid tank is used for collecting dirty liquid containing silicon slag, a plurality of partition cavities are formed in the centralized water tank and comprise a dirty liquid cavity, a primary filtering liquid cavity and a clear liquid cavity which are arranged in sequence, every two adjacent cavities are separated through a partition plate, and the centrifugal machine is used for collecting the dirty liquid containing the silicon slag. The height difference of the partition plates is set to only realize one-way overflow of liquid from the clear liquid cavity to the primary filtering clear liquid cavity and finally to the dirty liquid cavity; dirty liquid from dirty liquid tanks of all the machine tools is conveyed to the dirty liquid cavity, sewage in the dirty liquid cavity is conveyed to the centrifugal machine to be filtered and then conveyed to the primary filtrate cavity, the primary filtrate is conveyed to the cloth bag machine to be filtered and then returns to the clear liquid cavity, and clear liquid in the clear liquid cavity is conveyed to all the machine tools. In the circulation process of the cutting fluid, overflow among cavities in the centralized water tank keeps liquid level balance, and the flow of each water pump is controlled to ensure that the flow of each machine table is uniformly distributed.

Description

Technical Field

[0001] The invention relates to a combined filtering system and a processing method for simultaneously filtering silicon slag using multiple devices, belonging to the technical field of semiconductor silicon material processing. Background Art

[0002] Integrated circuit chips with line widths below 28 nm, especially 7 nm, not only place increasingly high demands on the performance of large silicon wafers, but also place stricter demands on silicon components used in etching machines, such as the uniformity of the silicon ring surface, mechanical damage to the inner wall of the silicon electrode micropores, and the surface morphology of the micropores. During the processing of silicon components, the cutting fluid of the machine tool is in direct contact with the workpiece. If the silicon slag and other particles in the cutting fluid are not separated and filtered in time, it is very easy to cause surface scratches and poor flatness of the product.

[0003] In traditional production, most of the filtration of silicon slag is done by centrifugal equipment for one-to-one processing of the machine. However, the filtration method of a single device requires a lot of supporting equipment, a large amount of cutting fluid loss, and a large area, which is not suitable for a more efficient and energy-saving production method. At present, when processing multiple devices at the same time, various liquid level sensors need to be added to ensure liquid level balance, but the sensors are expensive and easy to damage. The combined separation and filtration system for simultaneous processing of multiple devices has always been a problem that plagues production.

[0004] Therefore, achieving efficient filtration of silicon slag by multiple devices at the same time and reducing the cost of supporting centrifuge equipment, cutting fluid and other consumables are crucial to reducing costs and improving processing yields. Summary of the invention

[0005] The purpose of the present invention is to provide a combined filtering system for simultaneously filtering out silicon slag with multiple devices, solve the problem of combined treatment of cutting fluid in the process of silicon component processing, reduce the number of supporting centrifuge equipment and the amount of cutting fluid used, so as to reduce production costs and improve filtering efficiency.

[0006] Another object of the present invention is to provide a method for treating cutting fluid using the combined filtration system, which can simultaneously achieve efficient filtration of silicon slag in the cutting fluid of multiple processing machine tools.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A combined filtering system for filtering silicon slag with multiple devices at the same time, the combined filtering system comprises: a plurality of machine tool dirty liquid tanks, a centralized water tank, a centrifuge, and a bag filter, each machine tool dirty liquid tank is used to collect dirty liquid containing silicon slag, the centralized water tank contains a plurality of partition chambers, including a dirty liquid chamber, a primary filtration liquid chamber and a clear liquid chamber arranged in sequence, two adjacent chambers are separated by a partition, and the height difference of each partition is set to only realize one-way overflow of liquid from the clear liquid chamber to the primary filtration clear liquid chamber and finally to the dirty liquid chamber; dirty liquid from each machine tool dirty liquid tank is transported to the dirty liquid chamber, the sewage in the dirty liquid chamber is transported to the centrifuge for filtration and then to the primary filtration liquid chamber, the primary filtration liquid is transported to the bag filter for filtration and then returns to the clear liquid chamber, and the clear liquid in the clear liquid chamber is transported to each machine tool.

[0008] Preferably, in the combined filtration system, except for the bag filter where the liquid is discharged by gravity, the liquid in other parts is transported by a water pump to perform a reciprocating cycle.

[0009] Preferably, the machine sewage tank, centralized water tank, centrifuge, and bag machine are all connected by steel wire hoses.

[0010] Among them, the connecting pipe from the centrifuge liquid outlet to the primary filtration liquid chamber adopts a three-inch steel wire hose, the connecting pipe from the bag filter to the clear liquid chamber adopts a two-inch and above steel wire hose, and other connecting pipes in the filtration system all adopt one-inch steel wire hose.

[0011] A method for treating cutting fluid using the combined filtration system, during the entire circulation process of the cutting fluid, the liquid level balance is maintained by concentrating the overflow between the cavities inside the water tank; the flow rates of the bag machine, the centrifuge and the water pumps are controlled to ensure that the clear liquid after filtration matches the flow rates required by multiple machines operating simultaneously.

[0012] The advantages of the present invention are: The combined filtration system and treatment method of the present invention utilize a centralized water tank to realize the centralized treatment of cutting fluids of each independent machine. Through centrifugal filtration of the concentrated dirty liquid and secondary filtration by a bag filter, the clear liquid is again diverted and transferred through independent water pumps of each machine. The centralized treatment and diversion transportation method enables the filtration system to greatly reduce the number of supporting centrifuge equipment and the amount of cutting fluid, reduce the separation and filtration cost of silicon slag, reduce the failure rate, and improve the filtration efficiency through centralized treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the combined filtering system of the present invention for simultaneously filtering out silicon slag using multiple devices. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but this does not mean to limit the protection scope of the present invention.

[0015] like Figure 1 As shown, the combined filtering system for simultaneously filtering out silicon slag with multiple devices of the present invention comprises: a plurality of machine tool dirty liquid tanks, a centralized water tank, a centrifuge, and a bag filter. Each machine tool dirty liquid tank is used to collect dirty liquid containing silicon slag. The centralized water tank contains a plurality of partition chambers, including a dirty liquid chamber, a primary filtration liquid chamber, and a clear liquid chamber. The dirty liquid is transported to the dirty liquid chamber of the centralized water tank by a pump. The sewage in the dirty liquid chamber is pumped to the centrifuge for filtration and then returned to the primary filtration liquid chamber of the centralized water tank. The primary filtration liquid is pumped to the bag filter for filtration and then returned to the clear liquid chamber of the centralized water tank. The clear liquid in the clear liquid chamber is pumped to each machine tool by the water suction pump of each machine tool.

[0016] In this filtration system, the method of driving liquid circulation is as follows: the machine tool sprays clear liquid for processing, and the generated dirty liquid flows into the dirty liquid tank at the bottom of the machine tool by gravity. The dirty liquid in each dirty liquid tank is pumped to the dirty liquid chamber of the centralized water tank by a water pump, and the dirty liquid chamber is pumped to the centrifuge for filtration and then enters the primary filtration liquid chamber. The liquid in the primary filtration liquid chamber is pumped to the bag machine by a water pump for secondary separation and filtration. The liquid in the bag machine enters the clear liquid chamber of the centralized water tank by gravity, and the clear liquid in the clear liquid chamber is pumped to the liquid spray pipe of each machine by the water pump of each machine tool, thereby realizing the cutting fluid separation and filtration cycle of the entire combined filtration system.

[0017] According to the overflow direction between different cavities, by designing the height difference of the cavity partition plate, only one-way overflow from the clean liquid cavity to the primary filtered clean liquid cavity and finally to the dirty liquid cavity can be achieved, and overflow in the irreversible direction is irreversible. During the entire cutting fluid circulation process, the overflow between the cavities inside the water tank is concentrated to maintain the liquid level balance, and the flow distribution of each machine is guaranteed by controlling the flow of each water pump.

[0018] In the combined filtration system of the present invention, the volume of the machine tool dirty liquid tank is about 200L, and the total volume of the centralized water tank is 600L, including 300L of dirty liquid chamber, 180L of primary filtration liquid chamber, and 120L of clear liquid chamber. The total volume of the entire filtration circulation system is about 1m³, which ensures the supply of clear liquid and can effectively dissipate heat.

[0019] The connecting pipes in this combined filtration system are all made of steel wire hoses. The connecting pipe from the centrifuge liquid outlet to the primary filtration liquid chamber is connected by a three-inch steel wire hose, the connecting pipe from the bag filter to the clear liquid chamber is connected by a two-inch or above steel wire hose, and the other connecting pipes in the filtration system are all made of one-inch steel wire hoses.

[0020] In this combined filtration system, except for the bag filter which discharges liquid by gravity, the liquid in other parts is transported by a water pump for reciprocating circulation. The specifications of the water pump are: voltage 220V / 380V, speed 2800-3000r / min, flow rate 180-220L / min, output power 800-1200W, and head 18-20m.

[0021] The centrifuge speed in the combined filtration system is 2600-3200r / min, the hub silicon slag volume is 10-12kg, the centrifugal time is set to 300-800min, the scraping time is 3-5min, and the cleaning time is 1-2min. The silicon slag bucket at the bottom is used to clean the silicon slag separated by the system in time.

[0022] The bag machine in this combined filtration system adopts a multi-bag filter. The bag machine contains 5-6 bags. The spacing between each bag is 100-200mm. The overall size of the bag is: 800-100mm long and 300-500mm wide. The filtration accuracy is controlled at 1-200μm.

[0023] The combined filtration system of the present invention can ensure that the silicon slag of the cutting fluid is filtered out simultaneously when multiple processing machine tools are operating, and achieves efficient operation and reduces the cost of supporting equipment in a cycle of convergence-separation filtration-diversion. The combined filtration system of the present invention is easy to assemble and connect in terms of structure, convenient and fast during installation, easy to operate, and the centralized treatment of silicon slag of multiple equipment is efficient and convenient, which is welcomed by operators.

Claims

1. A combined filtration system for simultaneously filtering out silicon slag using multiple devices, characterized in that: The combined filtration system includes: multiple machine tool dirty liquid tanks, a centralized water tank, a centrifuge, and a bag filter. Each machine tool dirty liquid tank is used to collect dirty liquid containing silicon slag. The centralized water tank contains multiple partition chambers, including a dirty liquid chamber, a primary filtration liquid chamber, and a clear liquid chamber arranged in sequence. Two adjacent chambers are separated by a partition. The height difference of each partition is set to only achieve one-way overflow of liquid from the clear liquid chamber to the primary filtration clear liquid chamber and finally to the dirty liquid chamber; the dirty liquid from each machine tool dirty liquid tank is transported to the dirty liquid chamber, the sewage in the dirty liquid chamber is transported to the centrifuge for filtration and then to the primary filtration liquid chamber, the primary filtration liquid is transported to the bag filter for filtration and then returns to the clear liquid chamber, and the clear liquid in the clear liquid chamber is transported to each machine tool.

2. The combined filtration system for simultaneously filtering out silicon slag by multiple devices according to claim 1 is characterized in that: In the combined filtration system, except for the bag filter where the liquid is discharged by gravity, the liquid in other parts is transported by a water pump to perform a reciprocating cycle.

3. The combined filtering system for simultaneously filtering out silicon slag by multiple devices according to claim 1 or 2, characterized in that: The machine sewage tank, centralized water tank, centrifuge and bag machine are all connected with steel wire hoses.

4. The combined filtration system for simultaneously filtering out silicon slag by multiple devices according to claim 3 is characterized in that: The connecting pipe from the centrifuge liquid outlet to the primary filtration liquid chamber uses a three-inch steel wire hose, the connecting pipe from the bag filter to the clear liquid chamber uses a two-inch or above steel wire hose, and other connecting pipes in the filtration system use one-inch steel wire hoses.

5. The combined filtering system for simultaneously filtering out silicon slag by multiple devices according to claim 2 is characterized in that: The specifications of the water pump are: voltage 220V / 380V, speed 2800-3000r / min, flow rate 180-220L / min, output power 800-1200W, and lift 18-20m.

6. The combined filtering system for simultaneously filtering out silicon slag by multiple devices according to claim 1 is characterized in that: The centrifuge speed is 2600-3200r / min, the hub silicon slag volume is 10-12kg, the centrifugal time is set to 300-800min, the slag scraping time is 3-5min, and the cleaning time is 1-2min.

7. The combined filtering system for simultaneously filtering out silicon slag by multiple devices according to claim 1 is characterized in that: The bag machine adopts a multi-bag filter. The bag machine contains 5-6 bags. The spacing between the bags is 100-200mm. The overall size of the bags is: 800-100mm long and 300-500mm wide. The filtration accuracy is controlled at 1-200μm.

8. A method for treating cutting fluid using the combined filtration system according to any one of claims 1 to 7, characterized in that: During the entire circulation process of the cutting fluid, the liquid level balance is maintained by concentrating the overflow between the cavities inside the water tank; the flow rates of the bag machine, centrifuge and each water pump are controlled to ensure that the filtered clear liquid matches the flow required by multiple machines operating simultaneously.

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