JP2003309091A - Polishing drain recycling method in semiconductor production and breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reproduce and recycle the polishing drain, curtail the sludge from the polishing drain, and reduce the cost in a semiconductor production. <P>SOLUTION: The slurry drain in a polishing device is sent to a breaker 21. The breaker 21 breaks cohesive particles in the solution. The slurry drain after the breaking processing is sent to a liquid quality adjusting device 22. The liquid quality adjusting device 22 regulates a specific gravity of the slurry drain and prepares a pH. The slurry drain after the liquid quality adjusting processing is sent to enriched film units 49, 50, to be separated to an enriched liquid and a permeated liquid. After the enriched liquid is roughly filtered with a microfilter 57, it is stored in an enriched liquid tank 26. On the other hand, after the permeated liquid is partially stored in backwash chambers 64, 65, it is stored in a permeated liquid tank 27. An enrichment of the enriched film units 49, 50 is controlled by regulating the temperature of a heat exchanger 52 based on a flow rate measured by a flow meter 71. The enriched liquid is used as a regenerant and the permeated liquid is used for diluting a stock solution when preparing a new liquid. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of recycling a polishing waste liquid and a crushing device for reusing a waste liquid such as a polishing liquid used in a manufacturing process of semiconductors or the like into a polishing liquid.

In recent years, a chemical mechanical polishing device (hereinafter, simply referred to as a CMP device) has been adopted for flattening a wafer surface in a semiconductor manufacturing process, and a large amount of the chemical mechanical polishing device is produced in proportion to the amount of manufactured products. A slurry polishing liquid is used. Since the usage amount after polishing affects the manufacturing cost, it is required to efficiently reuse the polishing waste liquid after the wafer polishing discharged from the manufacturing process.

[0003]

2. Description of the Related Art Conventionally, various waste liquids have been discharged in the semiconductor manufacturing process. For example, when flattening the surface of a wafer, a commercially available stock solution of about 25% by weight (wt%) is used up to about 13% by weight. It is diluted with pure water before use. The used polishing liquid is further diluted in the polishing apparatus, and when it is a waste liquid, its concentration becomes, for example, about 0.1 to 0.2 wt%. Further, the collected polishing waste liquid contains a film scraped off from the wafer and impurities generated from the polishing table (pad or the like) of the polishing apparatus. Then, generally, the recovered polishing waste liquid is neutralized and then discarded, or is treated as drainage and turned into sludge, which is delivered to an industrial waste treatment company.

[0004]

By the way, in the polishing waste liquid (slurry waste liquid), although fine particles of abrasive grains are agglomerated and enlarged, the particle size of each abrasive grain is almost the same as that before polishing. , It remains the size that can be polished. Further, the polishing liquid used for flattening the wafer occupies a considerable part of the processing cost of the wafer, but the polishing waste liquid is discarded without being reused. That is,
Even though usable abrasive grains remained, they were discarded without being reused.If the polishing waste liquid can be reused, the semiconductor manufacturing cost can be reduced. Therefore, the polishing waste liquid can be reused. It was required to work. Further, the sludge disposal cost handed over to the industrial waste treatment company has also been one of the reasons for increasing the semiconductor manufacturing cost.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to recycle and reuse polishing waste liquid, thereby reducing sludge generated from polishing waste liquid and semiconductor. It is an object of the present invention to provide a polishing waste liquid reuse method and a reuse device in semiconductor manufacturing, which can reduce the manufacturing cost.

[0006]

In order to achieve the above object, the invention according to claim 1 is a polishing waste liquid for regenerating a polishing slurry waste liquid discharged from a polishing apparatus used in semiconductor manufacturing as a polishing liquid. It is a reuse method of. The method includes a crushing step of crushing aggregated particles of abrasive grains in the slurry waste liquid after polishing, and a concentration step of concentrating the slurry waste liquid after the crushing step. In the concentrating step, the slurry waste liquid is separated into a concentrated liquid and a permeated liquid by using a concentrating membrane, and a temperature controller is controlled based on a detected value of a flow rate of the permeated liquid separated by the concentrating membrane. By controlling the temperature of the slurry waste liquid, the degree of concentration of the concentrated liquid separated by the concentrating membrane is controlled.

A second aspect of the present invention is a method of reusing a polishing waste liquid in which a slurry waste liquid after polishing discharged from a polishing apparatus used in semiconductor manufacturing is regenerated as a polishing liquid. A crushing step of crushing aggregated particles of abrasive grains in the slurry waste liquid after polishing, a liquid quality adjusting step of adjusting the liquid quality of the slurry waste liquid after the crushing step, and a slurry waste liquid after the liquid quality adjusting step is a concentration film And a concentration step of concentrating by separating into a permeate and a permeate. At the time of cleaning the concentrated film, the permeated liquid separated by the concentrated film is stored in the chamber, and the concentration becomes too low to maintain the specified value based on the detected value of the flow rate of the permeated liquid separated by the concentrated film. If it is determined that the gas is purged into the chamber, the concentrated membrane is backwashed with the permeate, and the permeate used for the backwash is returned to the slurry waste liquid in the liquid quality adjusting step.

The present invention as set forth in claim 3 is provided in a polishing waste liquid reuse device in semiconductor manufacturing for regenerating, as a polishing liquid, a slurry waste liquid after polishing discharged from a polishing device used in semiconductor manufacturing. This is a crushing device for crushing the agglomerated particles of the abrasive grains in the slurry waste liquid. The crushing device includes a pressure circulation device that crushes the slurry waste liquid by applying it to the inner wall of the crushing chamber.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 is a schematic configuration diagram of a polishing waste liquid regeneration plant.

A plurality of polishing waste liquid recycling plants (hereinafter, simply referred to as plants) 1 as recycling devices are provided (for example, 3 plants).
Supply system for supplying the polishing liquid to the polishing device 2 of the table),
Polishing waste liquid (slurry waste liquid) discharged from each polishing device 2
We are building a circulation system that has a reproduction system that reproduces. The plant 1 includes a stock solution drum cabinet 4 in which a stock solution drum 3 is housed, a slurry supply device 5,
And a slurry waste liquid regeneration device 6. The polishing apparatus 2 is a chemical mechanical polishing apparatus (CMP apparatus), and is used for polishing a metal layer such as aluminum formed on a semiconductor wafer (hereinafter, simply referred to as a wafer) or an oxide film.

A stock solution containing abrasive grains (eg, alumina fine particles) is stored in the stock solution drum 3. The concentration of the stock solution is, for example, about 25 wt%. The stock solution drum 3 is connected to the slurry supply device 5 by a pipe line 7 and connected to the slurry waste liquid regenerating device 6 by a pipe line 8. By opening the valves 9 and 10 provided on the conduits 7 and 8,
The stock solution is supplied to each of the devices 5 and 6.

The slurry supply device 5 is provided with a mixing tank, and a predetermined amount of the stock solution supplied from the stock solution drum 3 is diluted and mixed in the mix tank to prepare a slurry solution. Pure water (DIW (diionized water)) used for dilution is supplied to the slurry supply device 5. The concentration of the prepared slurry liquid is, for example, about 13 wt%. Also, two mixing tanks are provided, and for example, two mixing tanks are used alternately. The slurry liquid prepared by the slurry supply device 5 is supplied to each polishing device 2 through the supply pipe 11 by opening the valve 12 provided on the supply pipe 11 that connects the slurry supply device 5 and each polishing device 2. To be supplied to. The supply amount of the slurry liquid to each polishing device 2 is adjusted by the opening degree of the valve 12.

In each polishing apparatus 2, while the slurry liquid is supplied onto the polishing pad of the rotating table, the surface to be polished of the wafer is pressed against the polishing pad by a predetermined force to polish the wafer. The slurry liquid used for polishing is diluted with water that has been poured out to prevent clogging by abrasive grains around the table, and then discharged as a slurry waste liquid. The concentration of the slurry waste liquid is, for example, about 0.1 to 0.2 wt.
%. The slurry waste liquid is discharged from each polishing device 2 to the discharge pipe line 1
It is discharged to the slurry waste liquid regenerator 6 through 3.

The slurry waste liquid regenerator 6 is a device for regenerating the slurry waste liquid, and permeates a slurry recycle concentrated liquid (hereinafter referred to as a slurry regenerant liquid) obtained by concentrating the slurry waste liquid to the same specified concentration as the slurry liquid. Separate into liquid. The slurry reclaimed liquid joins the slurry waste liquid regenerator 6 through the circulation conduit 14 serving as a circulation supply path into the supply conduit 11, and is recirculated and supplied to each polishing device 2. The circulation line 14 is branched on the way and is also connected to the slurry supply device 5. The slurry regeneration liquid is
The valves 15 and 16 provided on the circulation pipeline 14 are supplied to each polishing device 2 by opening, and the valves 17 are supplied to the slurry supply device 5 by opening. That is, by selecting the valves 15 to 17 to be opened, it is possible to switch the supply destination of the slurry regenerant between the polishing device 2 and the slurry supply device 5. Further, the permeated liquid is supplied to the slurry supply device 5 through a pipe line 18 as a permeated liquid supply path.
Is used for diluting the stock solution when preparing the slurry solution. The valves 9, 10, 12, 15 to 17 are controlled to open and close by a control device (not shown).

Next, the structure of the slurry waste liquid regenerator 6 will be described in detail. FIG. 2 is a schematic configuration diagram showing the slurry waste liquid regeneration device 6. The slurry waste liquid regeneration device 6 includes a crushing device 21,
Liquid quality adjusting device 22, concentrating device 23, coarse filtering device 24, backwashing device 25, concentrating liquid tank 26 and permeating liquid tank 27.
Equipped with.

The crushing device 21 is a device for crushing the aggregated and enlarged aggregated particles in the slurry waste liquid supplied from each polishing device 2. FIG. 3 is a schematic configuration diagram showing the crushing device 21. The crushing device 21 includes a crushing tank 32 having a crushing chamber 31. The crushing tank 32 has a mill 33
A stirrer 34 as a stirrer, and an ultrasonic oscillator 35
A pressure pump 37 is provided on the circulation pipe 36 connected to the crushing chamber 31. Ultrasonic oscillator 3
8 vibrates the ultrasonic oscillation plate 35 in the crushing chamber 31 at high frequency. The circulation pipe 36 and the pressure pump 37 constitute a pressure circulation device, and the ultrasonic oscillator 35 and the ultrasonic oscillator 38 constitute an ultrasonic vibration device.

The slurry waste liquid from the discharge conduit 13 is first injected into the mill 33 through the injection port 39. The mill 33 crushes aggregated particles in the slurry waste liquid. Stirrer 34 is crushing chamber 3
The slurry waste liquid stored in 1 is stirred. The ultrasonic oscillator 38 ultrasonically vibrates the ultrasonic oscillation plate 35 to crush and disperse the aggregated particles in the slurry waste liquid. The pressurizing pump 37 vigorously injects the slurry waste liquid into the slurry waste liquid in the crushing chamber 31 through the circulation pipe 36, and applies the slurry waste liquid to the inner wall of the crushing chamber 31 to crush the aggregated particles.

It is not always necessary to use three mills 33, pressurizing pumps 37 and ultrasonic oscillators 38, and one of the three to be used is selected as required. In particular, the combined use of the pressurized circulation crushing method using the pressure pump 37 and the ultrasonic vibration crushing method using the ultrasonic oscillator 38 is effective. The slurry waste liquid after the crushing process is transferred from the discharge port 40 of the crushing tank 32 to the pipeline 41.
And is discharged to the raw material tank 42 (see FIG. 2) of the liquid quality adjusting device 22, which is the next step. The circulation pipe 3
6 and the pressure pump 37 constitute a pressure circulation pump.

As shown in FIG. 2, the liquid quality adjusting device 22 includes
This is a device for adjusting the quality of the slurry waste liquid crushed by the crushing device 21. The liquid quality adjustment process is a pre-process for efficiently performing the subsequent concentration process in the concentration device 23, and includes a specific gravity adjustment process and a pH adjustment process. The liquid quality adjusting device 22 includes a raw material tank 42, an agitator 43, a concentration / specific gravity meter 44, a pH meter 45, a specific gravity controller 46 and p.
An H controller 47 is provided. Two treatments are agitator 43
Is carried out while stirring the slurry waste liquid.

The specific gravity adjusting process is carried out by using the density and specific gravity meter 44 and the specific gravity controller 46. The specific gravity of the slurry waste liquid in the raw material tank 42 is measured by the concentration / specific gravity meter 44, and the specific gravity controller 46 determines whether or not the specific gravity (that is, the concentration) of the slurry waste liquid has reached a specified value based on the measured value of the specific gravity. . If it does not reach the specified value, a new slurry liquid or a slurry regeneration liquid is added to control the specific gravity (concentration) of the slurry waste liquid. That is, the slurry regenerant is adjusted to a certain concentration value in advance so as to obtain the desired concentration. The specific gravity adjusting means is composed of a concentration specific gravity meter 44 and a specific gravity controller 46.

The pH adjustment process is performed by using the pH meter 45 and the pH controller 47. The pH value of the slurry waste liquid in the raw material tank 42 is measured by the pH meter 45, and the pH controller 47 calculates the p value of the slurry waste liquid based on the pH value.
It is judged whether the H value has reached the specified value, and if it has not reached the specified value, the pH of the slurry waste liquid is controlled by adding an alkaline solution or an acid. The pH value of the slurry waste liquid when discharged from the polishing apparatus 2 is about pH 9, and this is adjusted to a specified value of about pH 10.5. By increasing the pH value of the slurry waste liquid to a specified value, aggregated particles that have not been crushed are likely to collapse and the dispersibility of particles (abrasive grains) in the slurry waste liquid is increased. The pH adjusting means is
It is composed of a pH meter 45 and a pH controller 47.

The raw material tank 42 is connected through a pipe 48 to two concentrated membrane units 49 and 50 as a concentrated membrane processing apparatus. A pump 51 and a heat exchanger 52 as a temperature controller are provided in the middle of the pipeline 48. The pump 51 discharges the slurry waste liquid in the raw material tank 42 through the conduit 48 to each of the concentration membrane units 49 and 50. Further, the temperature of the slurry waste liquid is adjusted in advance by the heat exchanger 52 before being sent to the concentrated membrane units 49, 50. The supply of the slurry waste liquid to the concentration membrane units 49, 50 is controlled by the valves 53, 54 provided on the conduit 48.

The concentration membrane units 49, 50 are devices for performing a concentration process for separating the slurry waste liquid after the liquid quality adjustment process by the liquid quality adjustment device 22 into a concentrated liquid and a permeated liquid. The concentrated liquid separated in the concentration membrane units 49, 50 is discharged from the pipes 55, 56, roughly filtered by a micro filter 57 as a filtering device provided in the discharge route, and then passed through the discharge pipe 58. And is discharged to the concentrated liquid tank 26. Micro filter 57 is 2
One of them is provided by the valves 59 to 62. A flow rate controller 63 is provided on the discharge conduit 58, and the flow rate controller 63 controls the flow rate of the concentrated liquid. Further, since the unfiltered particles and the like in the concentrated liquid are removed by the rough filtration by the micro filter 57, the wafer is not damaged when the concentrated liquid accumulated in the concentrated liquid tank 26 is used as the slurry regenerating liquid. The concentrated liquid discharged to the concentrated liquid tank 26 is adjusted to have a concentration when used in the polishing apparatus 2, and is used as it is as a slurry regenerating liquid.

The backwash device 25 comprises the concentration membrane units 49, 5
Each of the concentration membranes of the concentration membrane units 49, 50 is provided with two backwash chambers 64, 65 for temporarily storing the permeate separated by 0, and utilizing the permeate stored in the backwash chambers 64, 65. It is a device for cleaning. The permeate separated by the concentration membrane unit 49 is stored in the backwash chamber 64 through the pipe 66, and the permeate separated by the concentration membrane unit 50 is stored in the backwash chamber 65 through the pipe 67. Each backwash chamber 64, on each pipeline 66, 67
Valves 68 and 69 are provided on the downstream side of 65, and the valves 68 and 69 are closed when the permeate is stored in the backwash chambers 64 and 65. The permeate is discharged to the permeate tank 27 through the discharge conduit 70 when the valves 68 and 69 are opened.

The flow rate of the permeated liquid is measured by a flow meter 71 provided on the discharge pipe line 70 as a flow rate detecting means. The flow controller 63 is a flow meter 71.
The flow rate value of the permeated liquid measured by is managed, and the temperature control of the heat exchanger 52 is performed based on the flow rate value. When the temperature of the slurry waste liquid is raised, the linear velocity passing through the concentrated membrane increases,
When the temperature of the slurry waste liquid is lowered, the linear velocity passing through the concentrated membrane decreases. The flow rate controller 63 controls the temperature of the heat exchanger 52 so that the flow rate of the permeate maintains a specified value, and if the specified value cannot be maintained, for example, it is time to wash the concentrated membrane (backwash time). to decide. The enrichment control means is composed of the heat exchanger 52, the flow controller 63, and the flow meter 71.

Each of the backwash chambers 64, 65 has a line 72, 7
Gas purging device 7 as a gas purging means
6 and 77 are connected. Then, by opening the control valves 74 and 75 provided on the pipes 72 and 73, high-pressure inert gas (nitrogen or argon) from the gas purge devices 76 and 77 enters the backwash chambers 64 and 65. It is being sent. Backwash chamber 64,65
By supplying gas into the backwash chamber 6,
The permeated liquid in 4, 65 flows backward through the pipelines 66, 67 and is strongly ejected to the concentrated membranes in the concentrated membrane units 49, 50 to wash the concentrated membranes. A return pipe 78 that is connected to the raw material tank 42 is connected to the pipes 55 and 56. When backwashing the concentration membranes of the concentration membrane units 49, 50, the valves 53, 5 located upstream of the concentration membrane units 49, 50 are used.
4 and the valve 7 on the pipelines 55 and 56 located on the downstream side
9 and 80 are closed, and the valve 8 on the return line 78 is closed.
This is performed by opening valves 1, 82. Therefore, the permeated liquid used for backwashing is returned to the raw material tank 42 through the return pipe line 78. The backwashing of the washing membranes of the concentration membrane units 49 and 50 is performed one by one.

The concentrated liquid in the concentrated liquid tank 26 is circulated in the circulation line 14.
And is supplied to the polishing device 2 or the slurry supply device 5. In addition, the permeated liquid in the permeated liquid tank 27 is the conduit 1
It is discharged from 8 and supplied to the slurry supply device 5. The concentrating device 23 is composed of the concentrating membrane units 49 and 50, the heat exchanger 52 used for controlling the degree of concentration thereof, the flow rate controller 63, the flow meter 71, and the like. Further, the backwash device 25 includes the backwash chambers 64, 6
5, control valves 74 and 75 and gas purging devices 76 and 77
Etc.

Next, the operation of the plant 1 will be described. The slurry waste liquid used for polishing in each polishing device 2 and discharged is
It is injected into the crushing chamber 31 of the crushing device 21. In the slurry waste liquid, there are agglomerated particles in which abrasive grains are agglomerated and enlarged. The size of the aggregated particles is about 500 nm in diameter.
The diameter of the particles (abrasive grains) when using a new solution is about 10
Since it is 0 nm, about 125 particles are aggregated. There is a possibility that various film pieces scraped from the wafer and impurities such as peeled substances from the polishing pad are mixed in the agglomerated particles, but the amount is negligible in comparison with the amount of the abrasive grains.

The slurry waste liquid containing agglomerated particles is received in the crushing chamber 31 through the inlet 39 in FIG. Aggregated particles in the slurry waste liquid received in the crushing chamber 31 are crushed by the mill 33. The aggregated particles remaining in the slurry waste liquid after the crushing process by the mill 33 are crushed and dispersed by the ultrasonic vibration generated from the ultrasonic oscillating plate 35 by the operation of the ultrasonic oscillator 38. Furthermore, the slurry waste liquid is pressurized and circulated through the circulation pipe 36 by the operation of the pressure pump 37, and the agglomerated particles hit the inner wall of the crushing chamber 31, whereby the crushing proceeds. In addition, it is not necessary to always operate the three mills 33, the pressurizing pump 37, and the ultrasonic oscillator 38, and it is possible to use only two effective combinations.

Here, the crushed particles are uniformly suspended and dispersed (dispersed) in the slurry waste liquid by stirring by the stirrer 34, and discharged from the discharge port 40. The slurry waste liquid discharged from the discharge port 40 is sent to the raw material tank 42 in FIG.

The specific gravity and pH of the slurry waste liquid in the raw material tank 42 are measured by the concentration specific gravity meter 44 and the pH meter 45, and the specific gravity controller 46 is based on the measurement result.
And the pH controller 47 controls the liquid quality.
The slurry waste liquid of which the liquid quality is controlled passes through the heat exchanger 52 by the pump 51 to the respective concentration membrane units 49, 5
Supplied to zero.

The slurry waste liquid supplied to each concentration membrane unit 49, 50 is separated into a permeate and a concentration liquid by the concentration membrane. The concentrated liquid is sent from the pipes 55 and 56 to the micro filter 57 and roughly filtered, and then the flow rate controller 6
It is discharged from the discharge pipe line 58 via 3 and is stored in the concentrated liquid tank 26. Further, the permeated liquid is temporarily stored in the backwash chambers 64 and 65 through the pipes 66 and 67, and thereafter,
It is discharged from the backwash chambers 64 and 65 while the flow rate is measured by the flow meter 71 and is stored in the permeated liquid tank 27.

The permeated liquid stored in the backwash chambers 64 and 65 is used for washing the concentrated membranes of the concentrated membrane units 49 and 50. In FIG. 2, in order to wash the concentrated film of the concentrated film unit 49, the valves 53 and 79 are closed, the valve 81 is opened, and then the control valve 74 is opened to reverse the inert gas such as nitrogen from the gas purging device 76. Blow into the wash chamber 64. The nitrogen gas is blown from the gas purging device 76 until the permeated liquid in the backwash chamber 64 is completely exhausted.
Similarly, for cleaning the concentrated film of the concentrated film unit 50, the permeated liquid stored in the backwash chamber 65 is used, and the gas purge device 7 is used.
The same is done using 7. Concentration membrane unit 49, 50
Will be used at the same time. When one of the concentration membrane units 49, 50 is being washed (backwashed),
Since the concentration work is performed using the other concentration film, the concentration work is not interrupted. That is, continuous operation can be performed by the two concentrated membrane units 49 and 50. Also, two micro filters 57 are provided, and by using the other one during the replacement work, the concentration work is not interrupted and continuous operation is possible.

In FIG. 1, the concentration of the concentrated liquid stored in the concentrated liquid tank 26 depends on the temperature of the slurry waste liquid and the heat exchanger 52.
It is adjusted by controlling the linear velocity when the slurry waste liquid passes through each of the concentration membranes of the concentration membrane units 49 and 50. In order to increase the concentration of the concentrated liquid, the temperature setting of the heat exchanger 52 is raised to increase the linear velocity of the liquid passing through the concentrated membrane. Further, in order to reduce the concentration of the concentrated liquid, the heat exchanger 5
Lower the set temperature of 2 to lower the linear velocity of the liquid passing through the concentration membrane. The linear velocity is controlled by the flow rate controller 63 based on the flow rate of the permeated liquid measured by the flow meter 71. The permeated liquid stored in the permeated liquid tank 27 is used in the slurry supply device 5 for diluting the stock solution when preparing a new slurry liquid.

As described above, according to this embodiment, the following effects can be obtained. (1) The slurry waste liquid used for polishing the semiconductor wafer is crushed by a crushing process to crush aggregated particles in the waste liquid, and then separated into a concentrated liquid and a permeated liquid, and the concentrated liquid is used as a slurry reclaiming liquid for the semiconductor wafer. Since it is reused for polishing, the amount of stock solution used for polishing can be significantly reduced and the amount of sludge generated can be reduced. Therefore, the manufacturing cost of a semiconductor device such as an LSI can be kept low.

(2) Since the crushing step of crushing the agglomerated particles in the slurry waste liquid is adopted, the abrasive grains in the regenerated liquid can be restored to the same particle size as the single particles in the new slurry liquid. (3) Since it is crushed by the mill 33, the effect of crushing aggregated particles is high. Further, in addition to the mill 33, the pressure circulation process by the pressure pump 37 and the ultrasonic vibration process using the ultrasonic oscillator 38 are used together, so that the aggregated particles can be crushed more reliably.

(4) Even if the concentration (specific gravity) of the slurry waste liquid in the polishing waste liquid is different, the specific gravity is adjusted in advance, so that a concentrated liquid having a desired constant concentration can be obtained. In addition, p
Since H is adjusted, the aggregated particles that have not been completely crushed in the crushing step can be easily broken, and the remaining aggregated particles in the process of being sent to the concentration membrane units 49, 50 can be broken apart even a little. The dispersibility of the abrasive grains can be increased.

(5) Since the stirring is performed by the stirrer 34,
The crushed particles can be uniformly dispersed in the liquid. (6) The concentrated liquid separated by the concentrating membrane is used as the microfilter 57.
Since coarse filtration is performed by using, it is difficult to damage a semiconductor wafer or the like when polishing with a slurry regenerating liquid.

(7) Since the permeated liquid is used for diluting the stock solution, a new slurry liquid having a high dispersibility of abrasive grains can be supplied. Further, since the permeated liquid is stored in the chambers 64 and 65 and the concentrated film is backwashed at a predetermined time when the contamination becomes severe, the concentrated film can be easily washed. Therefore, the permeated liquid can be effectively used.

(8) The flow rate of the permeated liquid separated in the concentration process is detected by the flow meter 71, and the set temperature of the heat exchanger 52 is controlled by the flow rate controller 63 based on the flow rate value to control the slurry before the concentration process. Since the temperature of the waste liquid is adjusted and the linear velocity of the concentration process is controlled, a concentrated liquid having a desired constant concentration can be obtained.

(9) A plurality (two) of concentration membrane units 49, 50 are prepared and each concentration membrane unit 49, 5
Since the backwash chambers 64 and 65 are individually prepared for each 0,
Even when one of the concentration membrane units 49 and 50 is being washed, the other one can be continuously operated without stopping the regeneration process by using the other.

(10) Since the two micro filters 57 are provided, the regeneration process can be continuously operated by using the other micro filter when replacing the micro filter. (11) Since the concentrated liquid having the same concentration as that used in the polishing device 2 is controlled, the concentrated liquid can be directly supplied to the polishing device 2 as a slurry regenerating liquid, and the concentration degree in the concentration treatment can be increased. The minimum value is enough.

(12) Since the finally regenerated concentrated liquid can be supplied to the polishing apparatus 2 through the circulation line 14, a regenerated supply circulation system can be constructed fully automatically. The above embodiment is not limited to the above, and may be implemented in the following modes.

The crushing device does not need to have three of the mill method, the ultrasonic vibration method, and the pressurized circulation method. It suffices if at least one of the mill 33, the ultrasonic wave oscillating devices 35 and 38, and the pressurizing and circulating devices 36 and 37 is provided. Further, it may include any two of these three. For example, a configuration in which an ultrasonic wave oscillating device and a pressure circulating device are provided side by side may be used.

A dispersant may be used in the crushing step to accelerate the crushing of the aggregated particles. The concentration treatment is not limited to the method of separating the concentrated liquid and the permeated liquid. For example, water may be evaporated to be concentrated. Further, the separation method is not limited to the method using a concentration membrane. For example, the circle-center separation method may be used. It is also possible to employ a method of obtaining a concentrated liquid by performing aggregation separation (precipitation or the like) and removing the upper liquid.

The concentrated liquid may have a higher concentration than that used in the polishing apparatus 2. For example, a method may be employed in which the concentrated liquid is supplied to the slurry supply device, and the permeated liquid is used in the slurry supply device to dilute the concentrated liquid to use as the slurry regenerant liquid.

A treatment for controlling the grain size of the abrasive grains may be added. Abrasive particles with a particle size less than a certain value, which has been reused a lot, may be disposed of as sludge. With this configuration, the polishing ability of the slurry liquid can be kept high forever.

The time for performing backwashing may be the time when the concentration treatment is performed a certain number of times. For example, counting the number of concentration processing,
When the count value reaches a preset set value, the backwash process is executed. Further, when the worker manages the degree of contamination of the concentrated film, and when it is determined from the value of the instrument or the like that it is time to wash, the backwashing process can be performed manually.

The concentration membrane unit is not limited to two units. It may be three or more. Of course, continuous operation cannot be performed at the time of cleaning, but only one unit may be used. ○ The number of micro filters is not limited to two. There may be three or more. Of course, continuous operation cannot be performed when replacing the microfilter, but only one may be used.

The abrasive grains in the slurry liquid (polishing liquid) are not limited to alumina. Other materials may be used. For example, corrodyl silica or diamond may be abrasive grains. ○ It is also possible to adopt a method in which the concentrated solution in the concentrated solution tank is transferred to the supply tank and then supplied to the polishing apparatus without constructing a circulation supply system.

The polishing apparatus is not limited to the CMP apparatus. Other polishing apparatus using a polishing liquid (slurry liquid) may be used. The polishing waste liquid used by the polishing waste liquid recycling method and the polishing waste liquid recycling device is not limited to the polishing waste liquid of the semiconductor wafer. It can be adopted for the purpose of reusing all the polishing waste liquid generated in the polishing step in semiconductor manufacturing. For example, the polishing waste liquid used for polishing the package can be regenerated.

[0052]

As described above in detail, according to the inventions described in claims 1 to 3, since the aggregating particles in the polishing waste liquid are crushed after use in the polishing apparatus, the polishing liquid is required. The particles can be restored to the particle size, and the polishing waste liquid can be regenerated.
Therefore, the polishing waste liquid can be regenerated and reused, and the sludge generated from the polishing waste liquid can be reduced and the cost in the semiconductor manufacturing can be reduced.

According to the first aspect of the present invention, when the concentration membrane used for concentrating the slurry waste liquid is contaminated for a long period of time, the concentration membrane can be easily washed by backwashing using the permeate. it can.

According to the second aspect of the present invention, by concentrating the slurry waste liquid after the crushing treatment, it is possible to obtain a regenerated liquid having a predetermined concentration that is easy to reuse. In addition, since the quality of the slurry waste liquid is adjusted in advance before the concentration, it is possible to obtain a concentrated liquid having a desired concentration no matter how the concentration of the slurry waste liquid changes.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a polishing waste liquid regeneration plant according to an embodiment.

FIG. 2 is a schematic configuration diagram of a slurry waste liquid recycling device.

FIG. 3 is a schematic configuration diagram of a crushing device.

[Explanation of symbols]

1 Polishing Waste Liquid Recycling Plant as Polishing Waste Liquid Reusing Device 2 Polishing Device 3 Raw Liquid Drum 5 Slurry Supply Device 14 Circulation Pipeline as Circulation Supply Line 18 Pipeline as Permeate Supply Line 21 Crushing Device 22 Liquid Quality Adjusting Device 25 Reverse Washing device 26 Concentrated liquid tank 27 Permeate liquid tank 33 Mill 34 Stirrer 35 as stirring means Ultrasonic vibrating plate constituting ultrasonic vibrating device 36 Circulating pipe 37 constituting pressurizing circulation device 37 Constituting pressurizing circulation device Pressurizing pump 38 as a pressurizing circulation pump Ultrasonic vibrator 44 constituting an ultrasonic vibrating device 44 Liquid quality adjusting device, concentration and specific gravity meter 45 constituting specific gravity adjusting means 45 pH meter constituting liquid quality adjusting device, pH adjusting means 46 Liquid Quality Adjusting Device, Specific Gravity Controller Constituting Specific Gravity Adjusting Means 47 Liquid Quality Adjusting Device, pH Controllers 49, 50 Constituting pH Adjusting Means Concentration film unit 52 as concentration device and concentration film processing device Concentration degree control means and heat exchanger 57 as temperature controller 57 Micro filter 63 as filtration device Flow rate controllers 64, 65 reversely as concentration degree control means Backwash chamber 71 as a chamber constituting a washing device Concentration control means and flowmeters 76, 77 as flow rate detecting means Gas purging device as gas purging means

Continued front page    (72) Inventor             1844-2 Kozoji-cho, Kasugai-shi, Aichi             Within Fujitsu VIS Ltd. (72) Inventor Masataka Fukuizumi             1844-2 Kozoji-cho, Kasugai-shi, Aichi             Within Fujitsu VIS Ltd. F term (reference) 3C047 FF08 GG17                 4D006 GA02 KA67 KC13 KC14 KE03P                       KE16Q PA02 PB08 PC01                 4D059 AA30 BE42 BE51 BF14 BF15                       BK11 BK22 CC10 EA01 EA05                       EA20 EB01 EB05 EB06

Claims (3)

[Claims] 1. A method for recycling a polishing waste liquid, which is a slurry waste liquid after polishing discharged from a polishing apparatus used in semiconductor manufacturing, as a polishing liquid, which is an aggregate particle of abrasive grains in the slurry waste liquid after polishing. And a concentration step of concentrating the slurry waste liquid after the crushing step, wherein in the concentration step, the slurry waste liquid is separated into a concentrate and a permeate using a concentration membrane, and the concentration is performed. In semiconductor manufacturing, the temperature controller controls the temperature of the slurry waste liquid based on the detected value of the flow rate of the permeated liquid separated by the membrane to control the concentration of the concentrated liquid separated by the concentrated membrane. Method of reusing polishing waste liquid. 2. A method for reusing a polishing waste liquid, which is discharged from a polishing apparatus used in semiconductor manufacturing, after polishing as a polishing liquid, which is an agglomerated particle of abrasive grains in the slurry waste liquid after polishing. A crushing step for crushing the liquid, a liquid quality adjusting step for adjusting the liquid quality of the slurry waste liquid after the crushing step, and a slurry waste liquid after the liquid quality adjusting step is separated into a concentrated liquid and a permeated liquid using a concentration membrane. And a concentration step for concentrating, wherein the permeate separated by the concentration membrane is stored in a chamber, and the degree of concentration is a specified value based on a detection value of the flow rate of the permeate separated by the concentration membrane. When it is determined that it is time to wash the concentrated membrane that cannot be maintained, the concentrated membrane is backwashed with the permeate by gas purging the chamber, and the permeate used for the backwash is the slurry of the liquid quality adjusting step. To waste liquid Polishing waste recycling method in to semiconductor manufacturing. 3. A polishing waste liquid reuse device in semiconductor manufacturing, which regenerates a polishing slurry waste liquid discharged from a polishing device used in semiconductor manufacturing as a polishing liquid, and is provided for polishing particles in the slurry waste liquid after polishing. A crushing device for crushing agglomerated particles, which is provided with a pressure circulation device for crushing the slurry waste liquid by hitting the inner wall of the crushing chamber.