WO2013054577A1 - Waste machining fluid circulation device and waste machining fluid circulation method - Google Patents

Abstract

Provided are a waste machining fluid circulation device and a waste machining fluid circulation method which are capable of maintaining the pH value of a machining fluid within a predetermined range. A waste machining fluid circulation device supplies a machining fluid to a machining device (1), circulates a used machining fluid, and supplies the used machining fluid again to the machining device (1). The waste machining fluid circulation device comprises a pH value measurement means (20) which measures the pH value of the used machining fluid, and is provided with a control means (30) which, according to the pH value measured by the pH value measurement means (20), controls whether or not a neutralizer is supplied to the used machining fluid. The control means (30) transmits, to a supply means (24), a supply instruction signal for supplying the neutralizer when the measured pH value is outside a predetermined range, and transmits, to the supply means (24), a supply stop signal for stopping the supply of the neutralizer when the measured pH value is within the predetermined range.

Description

Processing waste liquid circulation device and processing waste liquid circulation method

The present invention relates to a processing waste liquid circulation apparatus and a processing waste liquid circulation method for regenerating a processing waste liquid while circulating in the apparatus and reusing it as a processing liquid.

When manufacturing semiconductor devices, devices such as ICs and LSIs are formed in a plurality of regions on the surface of a substantially disk-shaped semiconductor wafer divided into a grid pattern by division lines. Each semiconductor device is manufactured by cutting the semiconductor wafer with a dicer or the like along the planned dividing line.

When cutting along the division line, supply the machining fluid to the machining blade. Cutting scraps are mixed into the machining fluid by the cutting process, and Li and the like of the semiconductor wafer are eluted as ions, and the pH value of the machining fluid varies. When the machining fluid whose pH value fluctuates high or low is reused, there is a risk that corrosion occurs on the electrode, pattern surface, etc. of the workpiece such as a semiconductor wafer, resulting in poor quality.

Thus, for example, Patent Document 1 discloses a dicing apparatus that monitors pH value and stores various cutting data at the time when the pH value is in an optimum state. The dicing apparatus disclosed in Patent Document 1 reproduces a state in which the pH value is optimal by using various stored cutting data.

Japanese Patent Application Laid-Open No. 07-169717

The dicing apparatus disclosed in Patent Document 1 tries to bring the pH value of the working fluid closer to the optimum state by using various cutting data when the stored pH value is in the optimum state. To do. Therefore, there is a problem that the pH value cannot be adjusted according to the pH value of the processing liquid at the present time, and in some cases, the pH value of the processing liquid may not be brought close to an optimum state.

Also, it is conceivable to always measure the pH value of the processing liquid, and to issue an alarm and stop the dicing device when the measured pH value is out of a predetermined range. However, it cannot be denied that the production efficiency decreases due to the dicing apparatus stopping.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a processing waste liquid circulation device and a processing waste liquid circulation method capable of maintaining the pH value of a processing liquid within a predetermined range.

In order to achieve the above object, a processing waste liquid circulation apparatus according to the present invention is a processing waste liquid circulation apparatus that supplies a processing liquid to a processing apparatus, circulates a used processing liquid, and supplies the processing liquid again to the processing apparatus. It has a pH value measuring means that measures the pH value of the used machining fluid, and controls whether or not to supply the neutralizing agent to the used machining fluid according to the pH value measured by the pH value measuring means. It is characterized by including a control means.

In the above configuration, the pH value of the used machining fluid is measured, and whether or not the neutralizing agent is supplied to the used machining fluid is controlled according to the measured pH value. Depending on the pH value, for example, when the pH value is high or low, by supplying a neutralizing agent, the pH value of the processing liquid can be adjusted to be close to the neutral value, and a workpiece such as a semiconductor wafer is cut. It is possible to prevent corrosion of the electrode, pattern surface, etc. from occurring.

Moreover, the processing waste liquid circulation apparatus according to the present invention is such that the processing apparatus is a dicing apparatus, a tank that stores used processing liquid, and a supply unit that supplies the neutralizing agent to the processing liquid in the tank. And when the measured pH value is outside the predetermined range, the control means transmits a supply instruction signal for supplying the neutralizing agent to the supply means, and the measured pH value is within the predetermined range. In this case, it is preferable that a supply stop signal for stopping the supply of the neutralizing agent is transmitted to the supply means.

In the above configuration, when the measured pH value is outside the predetermined range, a supply instruction signal for supplying the neutralizing agent is transmitted to the supply means, and when the measured pH value is within the predetermined range, A supply stop signal for stopping the supply of the neutralizing agent is transmitted to the supply means. Thereby, when the pH value is high or low, by supplying a neutralizing agent, the pH value of the machining liquid can be adjusted to be close to the neutral value. It is possible to prevent the surface from being corroded.

Further, in the processing waste liquid circulation apparatus according to the present invention, the neutralizing agent is preferably an aqueous solution containing inorganic phosphoric acid.

In the above configuration, since the neutralizing agent is an aqueous solution containing inorganic phosphoric acid, the pH value of the working fluid can be adjusted within a predetermined range without the pH value being biased to acidic or alkaline.

Moreover, it is preferable that the processing waste liquid circulating apparatus according to the present invention supplies the neutralizing agent to the processing liquid before use.

If the electrical conductivity of the processing liquid before use is approximately 0 μS / cm, the pH value may fluctuate rapidly during processing. In the above configuration, by supplying a neutralizing agent to the working fluid before use, rapid fluctuations in pH value can be suppressed, and corrosion of electrodes, pattern surfaces, etc. of workpieces such as semiconductor wafers can occur. Can be prevented in advance.

Next, in order to achieve the above object, a processing waste liquid circulation method according to the present invention is a processing waste liquid circulation method that supplies a processing liquid to a processing apparatus, circulates a used processing liquid, and supplies the processing liquid again to the processing apparatus. A step of measuring the pH value of the used processing liquid, and a step of controlling whether or not to supply a neutralizing agent to the used processing liquid according to the measured pH value. And

In the above configuration, the pH value of the used machining fluid is measured, and whether or not the neutralizing agent is supplied to the used machining fluid is controlled according to the measured pH value. Depending on the pH value, for example, when the pH value is high or low, by supplying a neutralizing agent, the pH value of the processing liquid can be adjusted to be close to the neutral value, and a workpiece such as a semiconductor wafer is cut. It is possible to prevent corrosion of the electrode, pattern surface, etc. from occurring.

Further, in the processing waste liquid circulation method according to the present invention, the processing device is a dicing device, a tank that stores used processing fluid, and a supply unit that supplies the neutralizing agent to the processing fluid in the tank. When the measured pH value is outside the predetermined range, a supply instruction signal for supplying the neutralizing agent is transmitted to the supply means, and when the measured pH value is within the predetermined range Preferably, a supply stop signal for stopping the supply of the neutralizing agent is transmitted to the supply means.

In the above configuration, when the measured pH value is outside the predetermined range, a supply instruction signal for supplying the neutralizing agent is transmitted to the supply means, and when the measured pH value is within the predetermined range, A supply stop signal for stopping the supply of the neutralizing agent is transmitted to the supply means. Thereby, when the pH value is high or low, by supplying a neutralizing agent, the pH value of the machining liquid can be adjusted to be close to the neutral value. It is possible to prevent the surface from being corroded.

In the processing waste liquid circulation method according to the present invention, the neutralizing agent is preferably an aqueous solution containing inorganic phosphoric acid.

In the above configuration, since the neutralizing agent is an aqueous solution containing inorganic phosphoric acid, the pH value of the working fluid can be adjusted within a predetermined range without the pH value being biased to acidic or alkaline.

Moreover, it is preferable that the processing waste liquid circulation method according to the present invention supplies the neutralizing agent to the processing liquid before use.

If the electrical conductivity of the processing liquid before use is approximately 0 μS / cm, the pH value may fluctuate rapidly during processing. In the above configuration, by supplying a neutralizing agent to the working fluid before use, rapid fluctuations in pH value can be suppressed, and corrosion of electrodes, pattern surfaces, etc. of workpieces such as semiconductor wafers can occur. Can be prevented in advance.

According to the above configuration, according to the pH value, for example, when the pH value is high or low, by supplying a neutralizing agent, the pH value of the processing liquid can be adjusted to be close to the neutral value. It is possible to prevent the occurrence of corrosion on the electrode of the workpiece such as a wafer, the pattern surface, and the like.

It is a schematic diagram which shows the structure of the processing waste liquid circulation apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the control apparatus of the processing waste liquid circulation apparatus which concerns on embodiment of this invention. It is a flowchart which shows the process sequence of CPU of the control apparatus of the processing waste liquid circulation apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the structure of the conventional process waste liquid circulation apparatus.

Hereinafter, the processing waste liquid circulation device in the embodiment of the present invention will be specifically described with reference to the drawings. The following embodiments do not limit the invention described in the claims, and all combinations of characteristic items described in the embodiments are not necessarily essential to the solution means. It goes without saying that there is nothing.

FIG. 4 is a schematic view showing a configuration of a conventional processing waste liquid circulation device. As shown in FIG. 4, the conventional processing waste liquid circulation device includes a supply path 11 and a supply pump 12 for supplying a processing liquid to a plurality of dicing devices (processing devices) 1. The working fluid is not particularly limited as long as the amount of heat generated during dicing can be reduced. For example, a solution obtained by adding an aliphatic polyhydric alcohol as a solvent to pure water may be used.

In the dicing apparatus 1, the semiconductor wafer is cut by a dicer or the like. The used machining fluid containing cutting waste and the like is stored in the raw water tank 14 through the discharge path 13. The used machining liquid stored in the raw water tank 14 may be discarded as it is, and a new machining liquid may be supplied from the supply tank 15 to the machining apparatus 1 or may be reused by a machining waste liquid circulation apparatus.

When the used machining fluid is reused, the used machining fluid stored in the raw water tank 14 is sucked up by the raw water pump 16 and sent out to the filter device 17. By using a filter such as a hollow fiber membrane as the filter device 17, impurities such as cutting waste contained in the used machining fluid can be eliminated.

The used machining fluid from which impurities have been removed by the filter device 17 passes through the ion exchange device 18 (ion exchange), whereby the conductivity decreases. This is because the electrical conductivity is high because Li or the like of a workpiece such as a semiconductor wafer is eluted as Li ⁺ ions in the working fluid during cutting.

The machining fluid after the ion exchange is temporarily stored in the buffer tank 19 and supplied to the supply tank 15 according to the remaining amount of the machining fluid in the supply tank 15.

When Li or the like of a workpiece such as a semiconductor wafer is eluted as Li ⁺ ions into the processing liquid, the pH value of the processing liquid also varies. However, the conventional processing waste liquid circulation device does not have a means for adjusting the pH value, and when the pH value of the used processing liquid is high or low, the electrode of the workpiece such as a semiconductor wafer, the pattern surface, etc. Corrosion may occur, resulting in poor quality.

Therefore, in the processing waste liquid circulation device according to the present embodiment, the pH value of the processing liquid is constantly measured, and whether or not the neutralizing agent is supplied according to the measured pH value can be controlled. FIG. 1 is a schematic diagram showing a configuration of a processing waste liquid circulating apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the processing waste liquid circulation device according to the present embodiment includes a supply path 11 and a supply pump 12 for supplying a processing liquid to a plurality of dicing devices (processing devices) 1.

In the dicing apparatus 1, the semiconductor wafer is cut by a dicer or the like. The used machining fluid containing cutting waste and the like is stored in the raw water tank 14 through the discharge path 13. The used machining fluid stored in the raw water tank 14 is sucked up by the raw water pump 16 and sent out to the filter device 17. By using a filter such as a hollow fiber membrane as the filter device 17, impurities such as cutting waste contained in the used machining fluid can be eliminated.

The used processing liquid from which impurities are removed by the filter device 17 is stored in the buffer tank 19. An ion exchange device 18 for adjusting the conductivity of the used machining fluid is connected to the buffer tank 19. The control device 30 opens and closes an electromagnetic on-off valve (valve) 32 in accordance with the measurement result of a conductivity meter (not shown) in the buffer tank 19 to drive / stop the pump 31 that supplies the machining liquid to the ion exchange device 18. .

The used working fluid adjusted so that the electric conductivity is within a predetermined range is guided to the mixing tank 21. The buffer tank 19 and the mixing tank 21 are provided with a pH meter (pH value measuring means) 20 for measuring the pH value of the stored machining liquid, and the pH value of the stored machining liquid is measured as needed. . In the present embodiment, the measured value of the pH meter 20 in the mixing tank 21 is used. Note that a conductivity meter may also be provided in the mixing tank 21. This is because when the neutralizing agent is supplied to the working fluid stored in the mixing tank 21, the conductivity of the working fluid mixed with the neutralizing agent can be measured.

The control device (control means) 30 acquires the measured value of the pH meter 20 as a detection signal, and determines whether or not the pH value of the used processing liquid is within a predetermined range. When the control device 30 determines that the pH value of the used machining fluid is outside the predetermined range, the control device 30 opens the electromagnetic open / close valve (supply means) 24 and stores it in the mixing tank 21 in order to adjust the pH value. The neutralizing agent is supplied from the neutralizing agent tank 23 to the working fluid.

By supplying the neutralizing agent, the pH value of the processing liquid in the mixing tank 21 is adjusted, and the pH value can be brought close to the neutral value “7”. Specifically, by supplying the neutralizing agent, the ratio of the neutralizing agent in the solvent of the processing liquid increases, so the degree of the influence of the acidic component or alkaline component eluted in the processing liquid on the entire solvent is reduced. The pH value approaches the neutral value. The neutralizing agent is preferably an aqueous solution containing inorganic phosphoric acid. This is because the pH value of the processing liquid can be adjusted within a predetermined range without biasing the pH value to acidity or alkalinity.

FIG. 2 is a block diagram showing the configuration of the control device 30 of the processing waste liquid circulation device according to the embodiment of the present invention. As shown in FIG. 2, the control device 30 is configured by a computer, and includes at least a CPU 301 that performs arithmetic processing according to a control program, a memory 302 that stores a control program, a storage device 303, an input interface 304, and an output interface 305. ing.

The detection signal and input signal from the pH meter 20, the input device 306, etc. are input to the input interface 304. From the output interface 305, in addition to the supply pump 12 and the raw water pump 16, the pump 31 that supplies the processing liquid to the ion exchange device 18, the electromagnetic on-off valve 32 that opens and closes the path to the ion exchange device 18, and the neutralizer tank 23 A control signal is output to an electromagnetic on-off valve (supply means) 24 that opens and closes a path for supplying the neutralizing agent.

FIG. 3 is a flowchart showing a processing procedure of the CPU 301 of the control device 30 of the processing waste liquid circulation device according to the embodiment of the present invention. In FIG. 3, the CPU 301 of the control device 30 acquires the measured pH value from the pH meter 20 (step S301), and determines whether or not the acquired pH value is within a predetermined range (step S302).

The predetermined range may be, for example, around 6 to 8 around the neutral value “7”. This is because a sufficient effect can be obtained by bringing the pH value close to '7'.

When the CPU 301 determines that the acquired pH value is outside the predetermined range (step S302: NO), the CPU 301 transmits a valve opening instruction signal for opening the electromagnetic opening / closing valve 24 (step S303), and the neutralizing agent Start supplying. When the CPU 301 determines that the acquired pH value is within the predetermined range (step S302: YES), the CPU 301 transmits a valve closing instruction signal for closing the electromagnetic on-off valve 24 (step S304), Stop supplying.

The CPU 301 determines whether or not the adjustment of the pH value has been completed (step S305). By adopting such a process, the pH value can be adjusted regardless of whether or not cutting by the dicing apparatus 1 is being performed.

When the CPU 301 determines that the adjustment of the pH value has not been completed (step S305: NO), the CPU 301 returns the process to step S301 and repeats the above-described process. When the CPU 301 determines that the adjustment has been completed (step S305: YES), the CPU 301 ends the process. For example, when it is determined that the acquired pH value is within a predetermined range and a valve closing instruction signal for closing the electromagnetic opening / closing valve 24 is transmitted, it may be determined in step S305 that the adjustment is completed. The processing procedure shown in FIG. 3 is executed at any time, and is controlled so that the pH value of the working fluid is within a predetermined range.

The machining liquid is stored while being stirred in the mixing tank 21, and is supplied to the supply tank 15 according to the remaining amount of the machining liquid in the supply tank 15.

As described above, according to the present embodiment, when the pH value of the processing liquid is high or low, the pH value of the processing liquid can be adjusted by supplying the neutralizing agent, and the semiconductor wafer or the like can be adjusted. It is possible to prevent the occurrence of corrosion on the electrode of the cut object, the pattern surface, and the like.

Note that a neutralizing agent may be supplied to the processing liquid before use. This is because pure water is mixed to produce a machining fluid, and thus the conductivity of the newly produced machining fluid is approximately 0 μS / cm. If the conductivity is approximately 0 μS / cm, the pH value may fluctuate rapidly during cutting. For example, the supply pump 12 and the raw water tank 14 are connected by a pipe (not shown), and the machining fluid path is opened and closed between the supply pump 12 and the raw water tank 14 (electromagnetic) on / off valve (not shown). )). By opening the on-off valve and circulating the processing liquid through the supply pump 12, the raw water tank 14, the raw water pump 16, the filter device 17, the buffer tank 19, the ion exchange device 18, and the supply tank 15, the processing liquid before use can be obtained. A neutralizing agent can be supplied.

If the neutralizing agent is supplied to the working fluid before use, the conductivity of the working fluid increases due to the influence of potassium ions and the like contained in the neutralizing agent. The electrical conductivity of the working fluid is preferably about 10 μS / cm. As a result, it is possible to suppress rapid fluctuations in the pH value, and it is possible to prevent the occurrence of corrosion on the electrode, pattern surface, etc. of the workpiece such as a semiconductor wafer.

In addition, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications and substitutions are possible within the scope of the present invention.

1 Dicing equipment (processing equipment)
14 Raw water tank 17 Filter device 18 Ion exchange device 20 pH meter (pH value measuring means)
21 Mixing tank (tank)
24 Electromagnetic on-off valve (supply means)
30 Control device (control means)

Claims (8)

A processing waste liquid circulating device that supplies a processing fluid to a processing device, circulates a used processing fluid, and supplies the processing fluid again to the processing device,
Having pH value measuring means for measuring the pH value of the used machining fluid,
A processing waste liquid circulating apparatus comprising a control means for controlling whether or not to supply a neutralizing agent to a used processing liquid according to a pH value measured by the pH value measuring means. The processing device is a dicing device,
A tank for storing used machining fluid;
Supply means for supplying the neutralizing agent to the processing liquid in the tank,
When the measured pH value is outside the predetermined range, the control means transmits a supply instruction signal for supplying the neutralizing agent to the supply means, and the measured pH value is within the predetermined range. The processing waste liquid circulation device according to claim 1, wherein a supply stop signal for stopping the supply of the neutralizing agent is transmitted to the supply means. The processing waste liquid circulation device according to claim 1 or 2, wherein the neutralizing agent is an aqueous solution containing inorganic phosphoric acid. The processing waste liquid circulation device according to any one of claims 1 to 3, wherein the neutralizing agent is supplied to the processing liquid before use. A processing liquid circulation method for supplying a processing liquid to a processing apparatus, circulating a used processing liquid and supplying the processing liquid again to the processing apparatus,
Measuring the pH value of the used machining fluid;
And a step of controlling whether or not to supply the neutralizing agent to the used processing liquid according to the measured pH value. The processing device is a dicing device,
A tank for storing used machining fluid;
Supply means for supplying the neutralizing agent to the processing liquid in the tank,
When the measured pH value is outside the predetermined range, a supply instruction signal for supplying the neutralizing agent is transmitted to the supply means, and when the measured pH value is within the predetermined range, 6. The processing waste liquid circulation method according to claim 5, wherein a supply stop signal for stopping the supply of the summing agent is transmitted to the supply means. The processing waste liquid circulation method according to claim 5 or 6, wherein the neutralizing agent is an aqueous solution containing inorganic phosphoric acid. The processing waste liquid circulation method according to any one of claims 5 to 7, wherein the neutralizing agent is supplied to the processing liquid before use.

Images