JP2994288B2 - Chemical liquid filter processing method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a chemical liquid filter (hereinafter, referred to as a filter) and an apparatus therefor. In particular, in the manufacture of a semiconductor device, a semiconductor substrate is placed in a chemical tank and the semiconductor substrate is cleaned. TECHNICAL FIELD The present invention relates to a method and an apparatus for purifying a filter used in a semiconductor device manufacturing apparatus for performing chemical liquid processing such as etching.

[0002]

2. Description of the Related Art It is necessary to reduce the circulating pressure by making a filter for cleaning a chemical solution, that is, a real solution, used for processing a semiconductor substrate hydrophilic. For this purpose, the newly replaced filter is made hydrophobic by alcohol, especially since it is hydrophobic, and then the alcohol is replaced with pure water in order to prevent the components of the alcohol from being mixed into the actual liquid.

Referring to FIG. 4, Japanese Patent Application Laid-Open No. 63-248414
A conventional method for purifying a chemical liquid filter with pure water disclosed in Japanese Patent Application Laid-Open Publication No. H10-209,878 will be described. In FIG. 4, from the chemical solution tank 10, the valve 18c → the pump 12 → the filter 14 → the valve 18b →
In addition to the circulation path returning to the chemical solution tank 10 and the drainage path for draining the liquid between the chemical solution filter 14 and the valve 18b through the valve 18a, the valve 18c and the pump 12 are connected to the second chemical solution tank 20 through the valve 18d. Has a path connected between them.

[0004] Then, alcohol is put into the second chemical liquid layer 20, the filter element of the filter 14 is subjected to a hydrophilic treatment through the pump 12, and then the alcohol in the filter is washed with pure water and used in a normal circulation line. I do. The Teflon (trade name) membrane filter is hydrophobic, so in a circulation line using inorganic chemicals, etc., the contact resistance to the filter is high and the flow of the chemical solution is poor, so the above-mentioned hydrophilic treatment is necessary. Becomes

[0005]

A first problem of the prior art is that there is no means for quantitatively confirming whether the filter element has been sufficiently substituted and has become hydrophilic.

The reason for this is that the filter replacement line for performing the hydrophilic treatment with alcohol is not controlled by a pressure gauge.

A second problem of the prior art is that there is no means for quantitatively confirming whether or not the replacement with pure water after performing the hydrophilicity-imparting treatment with alcohol has been reliably performed.

[0008] The reason is that the filter pure water replacement line is not managed by an alcohol concentration meter.

Accordingly, the present invention relates to Teflon (trade name)
An object of the present invention is to improve the reliability of substitution when replacing a filter in the order of alcohol and pure water before using the membrane filter in a semiconductor substrate manufacturing apparatus using an inorganic chemical.

[0010]

A feature of the present invention is to provide a treatment method for making a chemical solution filter used in a chemical solution circulation system from hydrophobic to hydrophilic, and comprising a Teflon (trademark) membrane filter which is hydrophobic with alcohol. The method for treating a chemical liquid filter comprises detecting a degree of hydrophilization with a pressure gauge while hydrophilizing, and then adding pure water and detecting with an alcohol concentration meter that the alcohol has been replaced by pure water.

Another feature of the present invention is that a first step of introducing the alcohol stored in the mixing tank into the chemical tank and the following step:
, The second circulating the alcohol from the chemical tank pressure gauge, a through chemical filter circulation system to return to the chemical tank
Yes and second step, then a third step of replacing the alcohol with a chemical filter for hydrophobic predetermined hydrophilic in pure water by going adding pure water to the chemical tank
In the method for treating a chemical liquid filter, the primary pressure of the chemical liquid filter and the alcohol concentration meter installed in the chemical liquid tank are managed during the second and third steps . Here, after the pressure gauge detects that the filter has become a predetermined hydrophilic property, the alcohol in the chemical tank is drained, and the mixed liquid of alcohol and pure water stored in the mixing tank is drained. The mixed solution is circulated by being introduced into the chemical tank, and pure water can be introduced into the chemical tank from a pure water pipe. Alternatively, when the pressure temporarily increases after the circulation of the mixture, alcohol can be introduced into the chemical solution tank from an alcohol pipe.

Another feature of the present invention is to provide a chemical solution filter used in a chemical solution circulating system for making the filter from hydrophobic to hydrophilic.
Treatment device for chemical liquid filter with alcohol circulation device
In order to control the primary pressure and the alcohol concentration of the chemical liquid filter, the chemical liquid filter processing device is provided with a pressure gauge and a concentration meter.

Another feature of the present invention is that an alcohol supply line, a pure water supply line, and the alcohol supply line are provided.
Alcohol is supplied from the line and the pure water supply line
A chemical solution tank to which pure water is supplied, and provided in the chemical solution tank.
Alcohol concentration meter, pressure gauge from the chemical tank,
A circulation system that returns to the chemical solution tank through a filter;
In order to perform pure water replacement while controlling the alcohol concentration in the chemical liquid tank and the primary pressure of the filter, a chemical liquid filter processing device equipped with a feedback function to change the alcohol concentration with the primary pressure change of the chemical liquid filter It is in.

According to the present invention, the change in the primary pressure of the filter can be quantitatively confirmed, and the alcohol concentration in the substitution line can be quantitatively confirmed. That is, in order to control the film quality state of the filter, a pressure gauge is attached, and the alcohol concentration is controlled by pressure fluctuation. For this reason, the replacement characteristics of the filter become uniform, and a larger circulation flow rate can be secured. For this reason, the reliability of the hydrophilicity of the filter is improved, and the circulation flow rate is stabilized. Also, the replacement of pure water can be ensured with an alcohol concentration meter.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a first embodiment of the present invention. The chemical solution tank 1 for performing a chemical solution treatment such as cleaning and etching of a semiconductor substrate is provided with an air sensor 6a including a sensor for detecting a low level liquid level LL and a sensor for detecting a high level liquid level H. An alcohol concentration meter 7a for measuring the concentration of the alcohol is provided.

There is a circulation path from the chemical tank 1 to the pump 2 → valve 8 g → filter 4 → valve 8 f → chemical tank 1, and a drain path from the pump 2 to the valve 8 g for draining through the valve 8 h. In the circulation path, a pressure gauge 3 for quantitatively confirming a change in the primary pressure of the filter 4 is provided between the valve 8g and the filter 4.

Further, a mixing tank 5 for storing alcohol or a mixture of alcohol and pure water is provided with a sensor for detecting a low level liquid level LL, a sensor for detecting an intermediate level liquid level L, and a high level An air sensor 6b comprising a sensor for detecting the liquid level H is provided, and an alcohol concentration meter 7b for measuring the concentration of alcohol is provided. 1 can be supplied through a valve 8e. Since the mixing tank 5 is located above the chemical tank 1, the liquid from the mixing tank 5 can be introduced into the chemical tank 1 only by its own weight.

Also, the piping for alcohol IPA allows
The alcohol can be supplied to the mixing tank 5 through the valve 8a, and can be supplied to the chemical tank 1 through the valve 8d.

In addition, pure water DIW piping allows pure water to be supplied to the mixing tank 5 through a valve 8b and to the chemical tank 1 through a valve 8c.

Next, the operation of the first embodiment of the present invention for making the newly replaced filter 4 hydrophilic will be described.
This will be described in detail with reference to FIG.

First, the valve 8a is opened, and the valves 8b and 8
After closing d and 8e, the alcohol is stored in the mixing tank 5 to a high level H.

When the air sensor 6b detects that the level of alcohol has reached a high level H, the valve 8a is closed,
The valve 8e is opened, and alcohol is introduced into the chemical tank 1 . The air sensor 6a recognizes the alcohol level H charged into the chemical tank 1, and when the alcohol level H reaches a fixed high level H,
The pump 2 operates and the circulation of alcohol is started. Here, "abnormal" means that the alcohol in the mixing tank 5 is at a low level L.
This is the case where the alcohol level in the chemical liquid tank 1 does not reach the high level H forever even when the level becomes L. Since this is the occurrence of a trouble in the equipment, measures are taken.

Although the indication of the pressure gauge 3 immediately after the start of circulation shows a high value, it gradually decreases as the filter 4 becomes hydrophilic. When the decrease in the circulation pressure is settled, it is determined that the filter element has become a predetermined hydrophilic property, the valve 8g is closed, the valve 8h is opened, and the alcohol in the chemical solution tank 1 is reduced to a low level L by the pump 2 at a time. Drain the alcohol.

In the meantime, the valve 8a is opened, the valves 8b, 8d and 8e are closed and the intermediate level L
Then, the valve 8b is opened, the valves 8a, 8c and 8e are closed, and pure water is introduced into the mixing tank 5 until the mixed liquid reaches a high level H. Make a 1: 1 mixture.

Next, the valve 8b is closed, and the valve 8b is closed.
e is opened and the mixed solution is introduced into the chemical tank 1 to start circulation. Also in this case, even when the mixed liquid in the mixing tank 5 becomes the low level LL, the mixed liquid in the chemical liquid tank 1 does not become the high level H forever, and it is “abnormal” when trouble occurs in the equipment.
The countermeasure is taken from.

Thereafter, in order to reduce the alcohol concentration, the pure water valve 8c is opened, and pure water is injected into the chemical solution tank 1 from a pure water DIW pipe.

At this time, if the ratio of pure water is too large and the surface energy for the filter element is slightly increased, and the circulation pressure is temporarily increased, the valve 8d is opened and the alcohol IPA pipe is opened. Alcohol is introduced into the chemical tank to increase the alcohol concentration in the chemical tank 1, thereby suppressing an increase in circulation pressure.

Thereafter, pure water is supplied again to bring the concentration of alcohol detected by the alcohol concentration meter 7a closer to zero, thereby determining that 100% pure water replacement has been performed.

The reason why the mixing tank 5 is provided is to drain all the alcohol in the alcohol-substituted filter once and to circulate it again with a mixed liquid of 1: 1 = pure water: alcohol. The time required for introducing the chemical solution can be reduced by the tank. Then, after the circulation using 100% alcohol, a mixture of alcohol and pure water (1: 1) is used without circulating pure water alone.
Pure water replacement can be performed gradually without applying extra pressure to the filter element, and the replacement efficiency can be increased.

After the predetermined processing of the filter is completed in this way, pure water is drained, and a chemical solution for processing the semiconductor substrate, that is, an actual solution is stored in the chemical solution tank 1 and the actual solution is circulated through the circulation path. The processing of the semiconductor substrate is performed in the chemical solution tank 1.

Next, a second embodiment of the present invention will be described.
This will be described with reference to FIG. Note that, in FIG. 3, the same or similar portions as those in FIG. 1 are denoted by the same reference numerals, and thus the duplicated description will be omitted.

In the second embodiment of the present invention shown in FIG. 3, the chemical tank 1 passes through the filter 4 via the pump 2 from the chemical tank 1.
In addition to the circulation line for returning to the above, a mixing tank 5 for mixing pure water and alcohol, a second chemical liquid tank 9 for storing an actual liquid is provided.

The second chemical tank 9 is provided with an air sensor 6c composed of a sensor for detecting the low level liquid level LL of the actual liquid and a sensor for detecting the high level liquid level H. 8i, the real liquid is introduced into the second chemical liquid tank 9, and the real liquid accumulated in the second chemical liquid tank 9 is supplied to the valve 8.
The first chemical solution tank 1 is fed through i.

Also, like the mixing tank 5, the second chemical tank 9 is also located above the first chemical tank 1, so that the actual liquid from the second chemical tank 9 can be used only by its own weight. Can be introduced.

When the hydrophilicity of the filter 4 and the replacement with pure water are completed as in the first embodiment, the liquid is drained from the first chemical liquid tank 1 via the pump 2.

During this time, the valve 8i is opened and the actual liquid is put into the second chemical liquid tank 9, and the valve 8i is closed by the quantitative detection of the air sensor 6c. After that, the valve 8j is opened to put the actual liquid into the first chemical liquid tank 1, and when the amount is recognized by the air sensor 6a, the valve 8j is closed and the pump 2 is started to start circulation.

[0038]

According to the present invention, since the substitution of alcohol is performed while controlling the properties of the filter element with a pressure gauge, the reliability of the hydrophilicity of the filter is improved.

Further, in the present invention, since the pure water replacement is performed while controlling the alcohol concentration in the filter circulation line, the accuracy of the filter for pure water replacement is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the first exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chemical tank, 1st chemical tank 2 Pump 3 Pressure gauge 4 Filter 5 Mixing tank 6a, 6b, 6c Air sensor 7a, 7b Densitometer 8a-8j Valve 9 Second chemical tank 10 Chemical tank 12 Pump 14 Filter 18a-18d Valve

Claims (6)

(57) [Claims] In a treatment method for making a chemical filter used in a chemical circulation system from hydrophobic to hydrophilic, a hydrophilic Teflon (trade name) membrane filter is hydrophilized with an alcohol and the degree of hydrophilization is increased. A method for treating a chemical liquid filter, comprising: detecting with a meter, and then adding pure water and detecting that the alcohol has been replaced by pure water with an alcohol concentration meter. 2. A first step of introducing the alcohol stored in the mixing tank into the chemical tank, and then transferring the alcohol to the circulation system returning from the chemical tank to the chemical tank through a pressure gauge and a chemical filter. A second step of circulating , and then
A third step in which pure water is added to the chemical solution tank to replace alcohol having a hydrophobic chemical solution filter with a predetermined hydrophilicity by pure water , wherein the second and third steps are performed.
A method for treating a chemical liquid filter, comprising: managing a primary pressure of the chemical liquid filter and an alcohol concentration meter installed in the chemical liquid tank during a step . 3. After detecting that the chemical liquid filter has become predetermined hydrophilicity by the pressure gauge, the alcohol in the chemical liquid tank is drained, and the alcohol and pure water stored in the mixing tank are mixed. The method according to claim 2, wherein the mixed solution is introduced into the chemical solution tank, the mixed solution is circulated, and pure water is introduced into the chemical solution tank from a pure water pipe. 4. The treatment of a chemical liquid filter according to claim 3 , wherein when the pressure temporarily rises after the circulation of the liquid mixture, alcohol is introduced into the chemical liquid tank from an alcohol pipe. Method. 5. An alcohol circulating device for changing a chemical solution filter used in a chemical solution circulation system from hydrophobic to hydrophilic.
A chemical liquid filter processing device , comprising: a pressure gauge and a concentration meter for controlling a primary pressure and an alcohol concentration of the chemical liquid filter. 6. An alcohol supply line, a pure water supply line, and alcohol supplied from the alcohol supply line.
And a chemical tank to which pure water is supplied from the pure water supply line.
And an alcohol concentration meter provided in the chemical solution tank,
From the chemical storage tank through a pressure gauge and a chemical filter, the chemical
With a circulation system returning to the tank, in order to perform pure water replacement while managing the alcohol concentration and the filter primary pressure in the chemical tank, with the change in the primary pressure of the chemical liquid filter,
An apparatus for treating a chemical liquid filter, comprising a feedback function for changing an alcohol concentration.