TWI504573B - Method and apparatus for recycling and processing of silicon wafer cutting and grinding waste - Google Patents

Description

矽 wafer cutting and grinding waste recycling method and equipment thereof

The present invention relates to a method and a device for processing silicon wafer waste, and particularly relates to a method for recycling and processing a silicon wafer cutting and polishing waste which can increase the added value of the product and can effectively solve the environmental pollution problem. Its equipment.

In the industry of manufacturing semiconductor wafers and solar panels, the cutting of wafers into thin and uniform wafers (sheets) is one of the standard processes, usually using a special wire saw (Wire Saw) as the cutting tool, and Using high hardness tantalum carbide (SiC, gold steel sand) as abrasive, supplemented with mineral oil esters such as polyethylene glycol (PEG), diethylene glycol (DEG), propylene glycol (PG) as cutting coolant Therefore, when the wire saw is reciprocating at high speed, the cutting ability of the wire saw can be improved by using the tantalum carbide as a medium to form a cutting action on the tantalum wafer, and at the same time, the polyethylene glycol is mainly composed. The cutting fluid is sprayed against the cutting part. On the one hand, in addition to being used for cooling and lubrication purposes, on the other hand, the tantalum powder and impurities generated during cutting can be taken out of the cutting channel, so that the wafer cutting process can be smoothly and smoothly. To carry out the follow-up process.

During the process of cutting and grinding the silicon wafer, the cutting fluid sprayed on the cutting zone and used after cutting will carry out the cutting area continuously with the smashing debris, impurities and the worn carbonized ruthenium generated during cutting. In addition, it has become a slurry-like waste sludge with extremely high particle concentration and turbidity. In the past, most of the domestic silicon wafer cutting manufacturers could only treat these waste sludges as waste, or burn them with heavy oil. The slag is buried, but it still needs to be paid for by the waste industry. If the waste sludge is treated by incineration, it will also generate a lot of carbon dioxide, which is quite environmentally friendly. Therefore, the waste generated after the cutting and polishing of the silicon wafer Sludge, incineration or landfill are not ideal treatment methods.

At present, foreign companies have tried to use filtration equipment to recover cutting oil in waste sludge, which usually uses thin film technology for solid-liquid separation. Although this method can obtain partial liquid reclaimed oil, it can be recycled when the wafer is cut and ground. It is used, but this method also produces a large amount of sludge (filter cake). These sludges still contain reusable niobium carbide, niobium and polyethylene glycol, but they are not recycled. The same waste causes burial, which also causes serious environmental problems. The recovery of reclaimed oil is only carried out by solid-liquid separation. The economic benefits are not satisfactory. The main reason is that the waste sludge does not obtain good pretreatment. The membrane pores are easily fouled, resulting in a decrease in the operating cycle of the membrane and an increase in cost.

In addition, in recent years, under the strong driving force of the solar energy industry, the carbonized bismuth originally used as a consumable has been seriously in short supply, and the polyethylene glycol used for lubrication and cooling has also been greatly increased in usage, and has become a considerable High expenditures, therefore, based on the consideration of cost and environmental factors, in addition to the recovery of reclaimed oil from waste sludge, the industry must also consider the use of carbonized niobium and tantalum powder, which is still of value. Separate and recycle to reduce the generation and total amount of waste, and reduce environmental pollution and disposal costs.

Therefore, how to strike a balance between recycling costs and environmental protection, there is still no efficient and cost-effective treatment method, which makes the wafer cutting industry more and more high in environmental protection and cost load, so how to actively improve Production quality and pollution prevention technologies to balance economic and environmental protection, reduce production costs, and improve industrial competitiveness have become the urgent goals of relevant industries.

The object of the present invention is to provide a tantalum wafer capable of reducing waste generation, relatively low recovery cost, and not only effectively solving environmental problems, but also separating waste products such as recyclable reclaimed oil and niobium carbide from waste. Recycling method for cutting and grinding waste.

A secondary object of the present invention is to provide a recycling processing apparatus for cutting and polishing waste of a silicon wafer which can reduce film clogging, prolong the operation life of the film, and increase the recovery processing efficiency.

According to the present invention, a method for recycling a crucible wafer cutting abrasive waste comprises the following steps: Step (A): placing a pre-dehydrated filter cake into a treatment tank, the filter cake being self-crystallized The slurry waste sludge produced after the circular cutting and grinding is produced by pressure filtration, and contains at least tantalum powder (Si), tantalum carbide (SiC), and residual cutting fluid composed mainly of polyethylene glycol (PEG).

Step (B): adding a reactant in the treatment tank, the filter cake is mixed and diluted into a working liquid, and the ruthenium in the working liquid is caused to react with the reactant to form a solid cerium oxide. (SiO ₂ ) and gaseous hydrogen (H).

Step (C): pumping the hydrogen in the treatment tank into a gas collection tank for compression storage.

Step (D): Separating the ruthenium and ruthenium carbide in the working liquid after the diluted sludge concentration by the specific gravity separation method for sorting and recycling.

Step (E): The working liquid of the crucible and the niobium carbide is selected, and the solid-liquid separation is performed by the membrane filtration method, so that the working liquid can be separated into solid ceria and liquid water, polyethylene glycol, etc. liquid.

Step (F): The liquid water and the polyethylene glycol are further subjected to reverse osmosis treatment to obtain reusable water and a recycled cutting fluid containing polyethylene glycol as a main component.

According to the above method of the present invention, there is provided a process for the recovery of a silicon wafer cutting abrasive waste, wherein, in the step (B), the reactant added may be water.

According to the above method of the present invention, there is provided a process for recovering a waste cutting waste of a wafer, wherein in the step (E), the solid-liquid separation used is performed by using a round flat UF film.

According to the above method of the present invention, the method for recovering and processing the silicon wafer cutting and polishing waste, wherein, after the step (F), the water recovered by the reverse osmosis can be returned to the treatment tank for the step (B). ) The catalyst is used.

According to the above method of the present invention, the method for recycling and processing the waste cutting waste of the wafer, wherein, after the step (F), the liquid polyethylene glycol can be further removed by distillation to remove residual moisture and waste oil to form Recycled oil for reuse.

According to the above method of the present invention, there is provided a method for recovering and processing a silicon wafer cutting and polishing waste, wherein in the step (F), the reverse osmosis treatment is performed by a RO or NF membrane.

According to the above method of the present invention, there is provided a method for recovering and processing a wafer-cutting and polishing waste, wherein, in the step (B), a pressurized gas is introduced into the treatment tank to be mixed into the working liquid.

According to the above method of the present invention, there is provided a method for recycling and processing a silicon wafer cutting abrasive waste, wherein after the step (D), the selected tantalum and tantalum carbide are further subjected to a drying treatment for packaging recovery.

According to the above method of the present invention, there is provided a method for recovering and processing a silicon wafer cutting and polishing waste, wherein in the step (E), water and polyethylene glycol in the working water body are extracted by a vacuum suction method.

Therefore, the present invention firstly mixes the filter cake with a water-based catalyst, so that the filter cake is diluted into a working liquid, thereby catalyzing the formation of cerium oxide and hydrogen with the cerium powder, and then extracting and recovering the hydrogen gas, and then, The specific gravity is separated by water to select the niobium carbide and the remaining niobium particles, and then the solid-liquid separation is performed to separate the working liquid into solid ceria and liquid water and polydiethanol. Finally, To further separate water and polyethylene glycol, so that the waste sludge produced in the original recycling process can be recycled with useful cerium particles, tantalum carbide, cerium oxide and polyethylene glycol to reduce waste. The total amount, reducing the waste to bury the way, and more with the production of hydrogen with commercial value, so that the invention can enhance the added value of utilization, and achieve the purpose of energy saving and waste reduction.

Referring to FIGS. 1 to 3, a first embodiment of the method for recovering a silicon wafer cutting and polishing waste according to the present invention comprises the following steps: Step (A): a filter cake 100 which has been subjected to pressure filtration dewatering treatment in advance (Filter Cake) is placed in a processing tank 200 by a feeding port 210, and the processing tank 200 is sealed. The filter cake 100 is Wafer Cutting Waste which is produced after cutting and grinding from the wafer. It is produced after preliminary pressure filtration, and contains at least a residual cutting fluid composed mainly of tantalum powder (Si), tantalum carbide (SiC), and polyethylene glycol (PEG).

In this embodiment, the slurry waste sludge is dehydrated by a plate-frame filter press (or a sludge dewatering machine), and the filter cloth of the filter press is used to intercept most of the waste sludge. The solid matter is further compressed by high pressure air to form a sludge-like filter cake. In addition to the powdered silicon (Si), tantalum carbide (SiC) and impurities, the filter cake still has a small amount of polyethylene. The diol (PEG) is mainly a cutting oil ester, and the present invention reprocesses and recycles the package in the filter cake 100.

Step (B): pumping a reactant in the treatment tank 200. In the present embodiment, the reactant is preferably a liquid containing a water component, and further, the liquid has a small amount The fine bubbles, so that the filter cake 100 originally in the form of sludge can be diluted into a working liquid 300 with bubbles and solids, and the aforementioned fine bubbles can be pre-treated by the venturi principle. After mixing, it is driven into the treatment tank 200, on the one hand, the mixing of the water body and the filter cake 100 can be accelerated to generate a chemical reaction, and on the other hand, the oil quality of the light-weight residual polyethylene glycol in the filter cake 100 can be improved. And impurities, by the buoyancy of the bubble lifted to the upper surface of the liquid to facilitate subsequent separation. Therefore, after a predetermined time, the reactant in the working liquid 300 forms a catalytic reaction with the tantalum powder, and gradually forms solid cerium oxide (SiO ₂ , glass sand) and gaseous hydrogen (H), and the chemical reaction formula is :Si+2H ₂ O → SiO ₂ (solid state) + 2H ₂ (gaseous state)

In this embodiment, the reactant is pumped by an aeration hole 220 near the bottom of the treatment tank 200, and the ratio of the liquid to the amount of bubbles contained in the reactant is preferably 3:1. And the liquid level of the working liquid 300 is slightly lower than the feeding port 210 to provide a hydrogen temporary storage space.

Step (C): After a predetermined time, the hydrogen in the upper layer of the treatment tank 200 is pumped from a gas outlet 230 into a gas collection tank 400 for compression storage, and the hydrogen gas generated may be separately distributed for sale to generate a heat source. use.

Step (D): Since the specific gravity of the cerium particles and the cerium carbide is higher than that of water (the specific gravity is 2.3 and the specific gravity of the cerium carbide is 3.2), after the hydrogen (H) is extracted from the treatment tank 200, the specific gravity can be separated. In the embodiment, the residual cerium particles and the cerium carbide are further separated in the working liquid 300. In the embodiment, the solid cerium carbide and the cerium particles which are sequentially settled at the bottom of the processing tank 200 can be further removed from the bottom. The blanking port 240 is discharged into a sieve drum 250 and subjected to a drying process for respective sorting recovery.

Step (E): The working liquid 300 which is selected from the granules and the cerium carbide is pumped into a filter tank 500 for solid-liquid separation. In the embodiment, the filter tank 500 has a telescopic tube 510, and the telescopic tube 510 The bottom end is connected to the processing tank 200, and a conical nozzle 520 is connected to the bottom end. The nozzle 520 can move up and down according to the liquid level of the working liquid 300, and the bottom end of the nozzle 520 is opened. The hole system is provided with a fine mesh (not shown) for pumping liquid such as water, cerium oxide and polyethylene glycol in the working liquid 300 into the filter tank 500.

Moreover, the filter tank 500 is provided with a semi-settling type solid-liquid separation unit 600. The solid-liquid separation unit 600 preferably uses a round flat UF film, as shown in FIG. 4, the overall structure of which will be A plurality of UF membranes 610 are grouped on a horizontal and pivotable collecting pipe 620, and a UF membrane 610 is driven by the motor 630 outside the filtering tank 500 to rotate around the collecting pipe 620, and the other side Then, using a pump 640, the liquid that has passed through the UF membrane 610 and collected in the header 620 is sucked by the suction of the pump 630 to make the liquid in the working liquid 300 liquid. The cutting fluid such as polyethylene glycol can be pumped out of the filter tank 500 by filtration of the UF membrane 610, and the solid matter such as solid cerium oxide or the like is trapped in the filter tank 500, and As the concentration of solid particles in the filter tank 500 is continuously increased, the cerium oxide and impurities can be subjected to evaporative drying treatment for recycling as a secondary building material (for example, as a brick, a building partition material or a paving floor tile, etc.) ) whereby the original working liquid 300 can be separated into a solid state A cutting fluid such as cerium oxide and liquid water or polyethylene glycol.

In this step, in order to extend the operation period of the UF film, a scraping member 650 may be suspended between each UF film 610, and the scraping member 650 may form an automatic scraping film on the film surface when the UF film 610 rotates. The role of to prevent membrane surface scale, blockage, and thus reduce the water filtration rate.

Step (F): the liquid water and the polyethylene glycol are further subjected to a reverse osmosis treatment of a reverse osmosis treatment unit 700, and the reverse osmosis treatment unit 700 may be performed by using a NF (Nano Filtration) membrane or an RO (Reverse Osmosis) membrane. In this embodiment, the RO membrane is used, and the RO membrane is only allowed to dialyze the pores of the water molecules to further separate the water and the concentrated polyethylene glycol, thereby obtaining recyclable water and polyethylene glycol. An oil ester as a main component, wherein the recovered water can be pumped to the treatment tank 200 of the step (B) in a return water line 710 to provide a catalytic reactant for use with the tantalum powder to reduce the amount of water required for the treatment tank 200. .

Step (G): the liquid polyethylene glycol can be further removed by distillation to remove residual water and waste oil, and the concentrated polyethylene glycol can be detected by a turbidimeter to form a recyclable product. The used reclaimed oil is sent to an oil storage tank 800, and the reclaimed oil can be separately packaged for use in a wafer cutting and polishing process.

Therefore, the present invention first uses a catalyst containing water as a main component to mix the filter cake 100 (waste sludge) which has been subjected to pressure filtration dewatering treatment, so that the filter cake 100 is diluted into a working liquid 300 having a low sludge concentration, and further The tantalum powder catalyzes the formation of solid cerium oxide and gaseous hydrogen, and then the hydrogen is extracted and recovered, and then the specific gravity is separated by water to select the cerium carbide and the remaining cerium in the working liquid 300. Then, the UF membrane 61 is used for solid-liquid separation, so that the working liquid 300 is separated into solid cerium oxide and liquid water and polydiethanol, and finally, the RO membrane is further separated into water and polyethylene. Alcohol, so that the waste sludge produced in the original recycling process can be recycled with useful niobium grains, tantalum carbide, cerium oxide and polyethylene glycol to reduce the total amount of waste and reduce waste for burial. The dilemma of the method, and more with the production of hydrogen with commercial value, enables the invention to enhance the added value of utilization, and achieve the purpose of energy saving and waste reduction.

As described above, the present invention has the following effects and advantages over the conventional wafer cutting and rubbing waste disposal method:

1. The present invention removes the waste filter cake 100 (sludge) which can not be processed any more, first by adding water to catalyze the hydrogen gas, and then separating and separating the cerium carbide and the cerium particles by the specific gravity, and by using the UF film 61 and the RO membrane. Provided to further separate cerium oxide, water and polyethylene glycol in the working liquid 300, and finally to produce hydrogen, cerium particles, cerium carbide, cerium oxide, water and polyethylene glycol for recycling. The invention can increase the added value of recycling, and the amount of waste such as sludge remaining after the treatment is relatively small, so as to achieve energy saving and waste reduction.

2. Before the solid-liquid separation process is carried out, the solid carbonized niobium and tantalum particles are selected by the specific gravity separation method to reduce the proportion of the solid matter in the working liquid 300, and the UF can be effectively delayed after the subsequent solid-liquid separation. The fouling of the membrane 610 and the concentration polarization of the working liquid 300 increase the life cycle of the membrane and reduce the cost.

3. In addition, the circular flat UF film 610 used for solid-liquid separation can greatly reduce the fouling of the membrane surface and the formation of the filter cake by utilizing the effect of synchronously being scraped when the membrane is rotated, so that the efficiency of the overall recycling treatment can be improved. And prolonging the operational life of the membrane, the invention can balance the recovery efficiency and cost.

However, the above is only one embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are all It should remain within the scope of this invention.

100. . . Filter cake

200. . . Processing tank

210. . . Feeding port

220. . . Aeration hole

230. . . exhaust vent

240. . . Drop opening

250. . . Sieve bucket

300. . . Working fluid

400. . . Gas collecting tank

500. . . Filter tank

510. . . flexible tube

520. . . Nozzle

600. . . Solid-liquid separation unit

610. . . UF film

620. . . Liquid collection tube

630. . . motor

640. . . Pump

650. . . Swing element

700. . . Reverse osmosis treatment unit

710. . . Return water pipeline

800. . . Oil storage tank

Fig. 1 is a block flow diagram showing the processing flow of the recycling processing method of the wafer cutting and grinding waste of the present invention.

Fig. 2 is a system structural diagram showing the overall arrangement of the recovery system for treating the filter cake of the present invention.

Figure 3 is a partial cross-sectional view showing the internal structure of the filter tank of the present invention.

Figure 4 is a partial cross-sectional view showing the cross-sectional structure of the circular flat UF membrane filtration device of the present invention.

100. . . Filter cake

200. . . Processing tank

250. . . Sieve bucket

400. . . Gas collecting tank

500. . . Filter tank

600. . . Solid-liquid separation unit

620. . . Liquid collection tube

630. . . motor

640. . . Pump

700. . . Reverse osmosis treatment unit

710. . . Return water pipeline

800. . . Oil storage tank

Claims (9)

The invention relates to a method for recycling and processing a silicon wafer cutting and polishing waste, comprising the following steps: Step (A): placing a pre-dehydrated filter cake into a processing tank, the filter cake is cut and ground from the silicon wafer. The generated slurry waste sludge is produced by pressure filtration, and contains at least tantalum powder (Si), tantalum carbide (SiC) and residual cutting fluid composed mainly of polyethylene glycol (PEG); step (B): Adding a reactant in the treatment tank, the filter cake is mixed and diluted into a working liquid, and the ruthenium in the working liquid is caused to react with the reactant to generate solid cerium oxide (SiO ₂ ) and Gaseous hydrogen (H), the reactant may be water; Step (C): pumping the hydrogen in the treatment tank into a gas collection tank for compression storage; Step (D): using the specific gravity separation method in the diluted sludge In the working liquid after the concentration, the ruthenium and niobium carbide in the separation liquid are further separated for sorting and recovery; step (E): the working liquid of the niobium and tantalum carbide is selected, and the solid-liquid separation is carried out by membrane filtration. To promote the separation of the working liquid into a solid dioxide矽 and liquid water, polyethylene glycol; and step (F): liquid water and polyethylene glycol are subjected to reverse osmosis treatment to obtain reusable water and polyethylene glycol as main component Recycle the cutting fluid. Wafer cutting and grinding waste as described in item 1 of the patent application scope The method for recovering the substance, wherein, in the step (E), the solid-liquid separation used is carried out by using a round flat UF film. The method for recovering and processing the wafer cutting and grinding waste according to the first aspect of the patent application, wherein after the step (F), the water recovered by the reverse osmosis can be returned to the processing tank for supply. The catalyst of step (B) is used. The method for recycling and processing the wafer cutting waste according to the first aspect of the patent application, wherein after the step (F), the liquid polyethylene glycol can be further removed by distillation to remove residual water and waste oil. To form a reclaimed oil that can be reused. The method for recovering and processing a wafer-cutting and polishing waste according to the first aspect of the invention, wherein, in the step (F), the reverse osmosis treatment is performed by using a RO or an NF membrane. The method for recovering and processing a wafer-cutting and polishing waste according to the first aspect of the invention, wherein, in the step (B), the pressurized gas is injected into the treatment tank to be mixed into the work. liquid. The method for recycling and processing the silicon wafer cutting and grinding waste according to the first aspect of the patent application, wherein after the step (D), the selected tantalum and the tantalum carbide are dried to be packaged and recovered. The method for recovering and processing a wafer-cutting and polishing waste according to the first aspect of the invention, wherein, in the step (E), water and polyethylene glycol in the working water body are extracted by a vacuum suction. The utility model relates to a recycling processing device for cutting a grinding waste of a wafer, comprising: a processing tank, which is a closed container for accommodating a waste filter cake and a working liquid mixed with water and liquid, and having a liquid level higher than a liquid level a port, a feeding port for drawing hydrogen gas, and a gas liquid pumping port adjacent to the bottom; a gas collecting groove for recovering hydrogen gas generated in the processing tank; and a filter tank having a telescopic tube; The telescopic tube extends from the outside into the treatment tank, and has a movable nozzle at the bottom end thereof for pumping liquid such as water, cerium oxide and polyethylene glycol in the working liquid into the filter tank; The separation unit is a circular flat UF membrane group and is disposed in the filter tank, and has a plurality of UF membranes, a cluster of the UF membrane and a horizontally pivotable liquid collection tube, and a plurality of liquid collection tubes are disposed outside the filter tank. a motor that drives the UF film to rotate around the collecting pipe, and a pump for picking up the liquid that is transmitted through the UF film and collected into the liquid collecting pipe; and a reverse osmosis filtering unit connected to the water of the pump End for further separation of water and concentrated aggregates Ethylene glycol, which is obtained by recyclable water and regenerated oil mainly composed of polyethylene glycol. The reverse osmosis filtration device has a return water pipeline through which the recovered water can be drawn back. Inside the treatment tank.