JPH09167752A - Method and device for chemical solution treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent recontamination of substrate surface by the impurities in a chemical solution by a method wherein an impurity removing device is separated from a chemical solution circulating system, the impurities attracted to an attraction plate are desorved and they are regenerated by the impurity removing device. SOLUTION: First, a washing fluid 2 is poured into an impurity removing device 9a provided in parallel with an impurity removing device 9b, a substrate 1 is washed by circulating the washing fluid 2, and at the same time, the impurities in the washing fluid 2 are removed. On the other hand, the impurity removing device 9a is regenerated. Then, a washing fluid 2 is poured into the impurity removing device 9b, the substrate 1 is washed by circulating the washing fluid 2, and at the same time, the impurities in the washing fluid 2 are removed. On the other hand, the other impurity removing device 9a is regenerated. The impurities in the washing fluid 2 are continuously removed by repeating the above-mentioned operations. As a result, the function of the impurity removing devices 9a and 9b can be maintained, the impurity density of the washing fluid 2 can be lessened, and the adhesion of impurities to the surface of the substrate can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for chemical treatment of a semiconductor substrate in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductors, fine elements are formed on the surface of a semiconductor substrate (hereinafter referred to as a substrate), so that a clean substrate surface is required. Therefore, in the substrate cleaning step, cleaning is performed using various highly pure acid / alkali solutions. In a conventional cleaning apparatus, for example, as shown in FIG. 3, a processing tank 3 for cleaning a substrate 1 by immersing the substrate 1 in a cleaning liquid 2 composed of an alkaline solution such as a mixed solution of ammonia water / hydrogen peroxide solution is called an inner tank 3a. Double structure with outer tank 3b, inner tank 3
The cleaning liquid 2 overflowing from a to the outer tub 3b is circulated by the air-driven pump 4 and the resin filter 5 (hereinafter,
A device is known in which the inner tank 3a is caused to flow back through a filter 5). The filter 5 removes particulate impurities contained in the cleaning liquid 2 and having a particle size of 0.05 to 0.1 μm or more.

Further, due to recent miniaturization of semiconductor devices,
A cleaning device that can form a cleaner substrate surface is required,
A cleaning device provided with an impurity removing device capable of removing fine particulate impurities (hereinafter referred to as fine particle impurities) and metal impurities having a pore diameter of the filter 5 or less, for example, a particle diameter of 0.05 μm or less, has also been devised. FIG. 4 shows, for example, Japanese Patent Laid-Open No. 4-6132.
It is a block diagram which shows the impurity removal apparatus 6 of the 9th publication.
As shown in the figure, a potential is applied to the adsorption plate 7 made of a conductive material, and the charged impurities 8 in the cleaning liquid 2 are adsorbed by the adsorption plate 7 and captured.

By providing such an impurity removing device 6 in the circulation system of the cleaning liquid 2 in the cleaning device as shown in FIG. 3, fine particle impurities and metal impurities can also be removed. Here, a layer having a charge is formed on the surface of the particulate impurities in the cleaning liquid 2, and various metal impurities such as Al, Fe, and Cu also have a positive or negative charge, and thus pass through the filter 5. The formed fine particle impurities and metal impurities are removed as charged impurities 8.

[0005]

Since the conventional cleaning device is configured as described above, while the cleaning liquid 2 flows through the impurity removing device 6, the particulate plate 7 and the metal impurities in the cleaning liquid 2 are adsorbed on the adsorption plate 7. It is adsorbed on and captured. It is difficult for the impurity removing device 6 to capture the impurities completely unlike the filter 5 in which the impurities are captured by a mesh like the filter 5,
Some passed. Further, by repeating the cleaning of the substrate 1, the amount of impurities adsorbed on the adsorption plate 7 increases, but the impurities are further trapped in this state, and the trapping ratio gradually decreases. . Therefore, there is a problem that impurities such as fine particle impurities and metal impurities are accumulated in the cleaning liquid 2, and the impurities adhere to the surface of the substrate 1 to recontaminate the substrate 1.

FIG. 5 is a graph showing the correlation between the concentration of various metal impurities in the cleaning liquid 2 and the amount of the metal impurities deposited on the substrate 1. In order to prevent such recontamination of the substrate 1, it has conventionally been necessary to frequently replace the cleaning liquid 2 with a new one or replace the impurity removing device 6.

The present invention has been made to solve the above problems, and in a chemical treatment apparatus such as a substrate cleaning apparatus, the cleanliness of the chemical can be easily maintained at a low cost, The purpose is to effectively prevent recontamination of the substrate surface due to impurities therein.

[0008]

According to a first aspect of the present invention, there is provided a chemical solution treating apparatus, wherein a mechanism for circulating a chemical solution and a circulation system for the chemical solution are provided to apply an electric potential to an adsorption plate made of a conductive material. The impurity removing device for removing impurities in the chemical liquid by adsorbing the impurities by disconnecting the impurity removing device from the circulation system of the chemical liquid, and desorbing the impurities adsorbed on the adsorption plate to remove the impurities. And a mechanism for reproducing.

The chemical solution treating apparatus according to a second aspect of the present invention is provided with a filter for removing particulate impurities in the chemical solution on the inlet side of the impurity removing apparatus of the chemical solution circulating system.

A chemical treatment apparatus according to a third aspect of the present invention is provided with a plurality of impurity removing devices in parallel, and the plurality of impurity removing devices are alternately used in a chemical liquid circulation system to remove impurities in the chemical liquid. However, the removal of impurities in the chemical liquid and the regeneration of the impurity removal device can be performed simultaneously.

According to a fourth aspect of the present invention, there is provided a chemical liquid treatment device, wherein a mechanism for regenerating the impurity removing device has a regenerator supply device for desorbing impurities adsorbed by the adsorption plate into the liquid, and the used regenerating device. A device for supplying pure water or air for replacing the liquid is provided.

The chemical solution treating apparatus according to a fifth aspect of the present invention uses an acidic solution as a regenerating solution or a solution obtained by mixing the acidic solution with an oxidizing agent.

In the chemical liquid processing apparatus according to claim 6 of the present invention, the impurity processing apparatus comprises a chemical-resistant cylindrical wall surface, and a voltage is applied to the cylindrical wall surface made of a conductive material.
A plurality of comb-shaped suction plates opposed to each other, and a plurality of plates corresponding to comb teeth of the two comb-shaped suction plates are alternately arranged.

According to a seventh aspect of the present invention, in the chemical solution treating apparatus, the impurity removing apparatus comprises a chemical-resistant cylindrical wall surface and an adsorption plate made of a conductive material and capable of applying a voltage in the cylindrical wall surface. In addition, the surface of the suction plate is uneven.

In the chemical treatment method according to the eighth aspect of the present invention, when the regenerant is supplied, the adsorbing plate of the impurity removing device is applied with a positive and negative electric potential opposite to that at the time of adsorbing the impurities to adsorb the adsorbed impurities into the regenerant. It is to be detached inside.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Embodiment 1 of the present invention will be described below with reference to the drawings. Note that the description of the same parts as those of the conventional technique will be appropriately omitted. 1 is a configuration diagram showing a cleaning device as a chemical liquid processing device according to a first embodiment of the present invention. In the figure, 1 to 5 are the same as the conventional ones, particularly 2 is a cleaning liquid as a chemical liquid, and 9a and 9b are provided in parallel in the circulation system of the cleaning liquid 2 and are charged with charges such as fine particle impurities and metal impurities. Impurity removing device for removing impurities, 10 is a controller connected to the impurity removing devices 9a, 9b for adjusting the potential, 11 is a regenerant supply device for regenerating the impurity removing devices 9a, 9b, 12
Is a pure water supply device used when regenerating the impurity removing devices 9a and 9b, and 13 is a purge air supply device. 14 to 18 are valves provided in the pipe,
4a and 14b are valves provided before and after the impurity removing devices 9a and 9b of the pipe through which the cleaning liquid 2 passes, and 15a and
Reference numeral 15b is a valve provided in front of and behind the impurity removing devices 9a and 9b of the pipe for the regenerating process, 16 is a valve for controlling the supply of the regenerant, 17 is a valve for controlling the supply of pure water, and 18 is for purging. A valve that controls the supply of air, and 19 is a waste liquid port for the regenerating liquid and pure water used in the regenerating process.

FIG. 2 is a sectional view showing the structure of the impurity removing devices 9a and 9b. FIG. 2 (a) is a longitudinal sectional view of the whole, and FIG.
2B is a sectional view taken along the line AA in FIG. 2A, and FIG. 2C is a sectional view taken along the line BB in FIG. 2A. In the figure, 20 is a cylindrical wall made of a chemical resistant resin (hereinafter referred to as a resin cylinder), and 21a and 21b are installed inside the resin cylinder 20 and are made of a conductive material such as silicon or a silicon compound. Each of the suction plates is connected to the controller 10 (see FIG. 1) to adsorb a charged impurity by applying a voltage.
As shown in FIG. 2, two comb-shaped suction plates 21 a and 21 b face each other inside the resin cylinder 20.
A plurality of plates corresponding to the teeth of the combs 1a and 21b are alternately arranged.

The operation of the cleaning apparatus constructed as above will be described below. First, the cleaning liquid 2 is passed through one of the impurity removing devices 9a provided in parallel and circulated to clean the substrate 1, and at the same time, the impurities in the cleaning liquid 2 are removed. During this period, the other impurity removing device 9b is regenerated. This process is called process A. Next, the cleaning liquid 2 is passed through the impurity removing device 9b that has completed the regeneration treatment and circulated to clean the substrate 1, and at the same time, the impurities in the cleaning liquid 2 are removed. During this period, the other impurity removing device 9a is regenerated. This step is called Step B. Impurities in the cleaning liquid 2 are continuously removed by alternately repeating the steps A and B for a predetermined time.

The above step A will be described in detail below. First, open the valve 14a and close the valve 14b,
A controller 10 applies a positive and negative electric potential to the two adsorption plates 21a and 21b of the impurity removing device 9a, for example, ± 5 to 50.
Give with V. In this state, the cleaning liquid 2 overflowing from the inner tank 3a of the processing tank 3 to the outer tank 3b is sucked by the air-driven pump 4, and the filter 5 and the impurity removing device 9a.
The cleaning liquid 2 is continuously circulated by being refluxed to the inner tank 3a via the. At this time, particulate impurities having a particle size of 0.05 to 0.1 μm or more contained in the cleaning liquid 2 are filtered by the filter 5.
The fine particle impurities having a particle size of 0.05 μm or less and various metal impurities such as Al, Fe, and Cu which have been removed by the filter 5 and have a positive or negative charge in the cleaning liquid 2 are stored in the impurity removing device 9a. It is captured by the adsorption plates 21a and 21b by electroadsorption.

The suction plates 21a, 21 according to this embodiment
As shown in FIG. 2, two suction plates 21a and 21b are comb-shaped, and a plurality of plates corresponding to the teeth of the comb are alternately arranged.
The contact area between the a and 21b facing each other is increased, and the charged impurities in the cleaning liquid 2 can be effectively captured.

The other impurity removing device 9 is operated simultaneously with the circulation of the cleaning liquid 2 through the one impurity removing device 9a.
The reproduction process of b will be described below. First, the valve 15a is closed, the valve 15b is opened, the valve 17 is opened, and pure water is introduced from the pure water supply device 12 into the impurity removing device 9b. As a result, the cleaning liquid 2 remaining in the pure water supply device 12 is replaced with pure water. Next, the valve 17 is closed and the valve 16 is opened to introduce the regenerant from the regenerant supply device 11 into the impurity removing device 9b. As the regenerating liquid, for example, an acidic solution such as dilute hydrochloric acid or dilute hydrofluoric acid or a solution obtained by mixing an oxidizing agent such as hydrogen peroxide solution with these acidic solutions is used. At the time of introducing the regenerant, the controller 10 gives the positive and negative potentials opposite to those when the impurities in the cleaning liquid 2 are adsorbed to the adsorption plates 21a and 21b in the impurity removing device 9b.
As a result, the impurities electrically adsorbed on the adsorption plates 21a and 21b are desorbed in the regenerant. Of these, various metal impurities are dissolved in the regeneration solution, which is an acidic solution.

Next, the valve 16 is closed and the valve 17 is opened, and pure water is again introduced from the pure water supply device 12 into the impurity removing device 9b to wash it, whereby the adsorption plates 21a,
Impurities desorbed from 21b, together with the regenerant, are drained 19
Discharged from Further, the valve 17 is closed and the valve 18 is opened to introduce air from the air supply device 13 into the impurity removing device 9b for purging. The regeneration liquid and the pure water used for the regeneration treatment are all discharged from the waste liquid port 19. Then, the valve 18 is closed to complete the regeneration process of the impurity removing device 9b.

After the processing by the step A as described above, the processing by the step B is performed. In step B, the valve 14a is closed,
14b is opened, the valve 15a is opened, and the valve 15b is closed, and the impurity removing device 9b regenerated in the step A is used for the circulation system of the cleaning liquid 2, and the impurities removal used for the circulation system of the cleaning liquid 2 in the step A is performed. The device 9a is separated from the circulation system and regenerated. The method of treatment is the same as in step A.

In this embodiment, the impurity removing device 9
Since the cleaning device is provided with a mechanism for regenerating a and 9b, even if the trapping rate of impurities by the adsorbing plates 21a and 21b is reduced, the adsorbed impurities are desorbed from the adsorbing plates 21a and 21b to regenerate the impurities. Removal device 9a, 9b
The function of can be maintained. Therefore, the concentration of impurities in the cleaning liquid 2 can be reduced, and the adhesion of impurities to the surface of the substrate 1 can be effectively prevented. Further, since the cleaning liquid 2 once prepared can be used for a long time without increasing the impurity concentration, it is almost unnecessary to replace the cleaning liquid 2, and the cost can be reduced.

When the impurity removing devices 9a and 9b are regenerated, the adsorbing plate 21 is supplied by supplying a regenerating liquid.
The impurities adsorbed on a and 21b are desorbed into the regenerant. At this time, since positive and negative electric potentials are applied to the adsorption plates 21a and 21b, which are opposite to those when the impurities are adsorbed, the adsorption plates 21a and 21b
Detachment from b can be reliably performed. Further, since an acidic solution such as dilute hydrochloric acid or dilute hydrofluoric acid or a solution obtained by mixing an oxidizing agent such as hydrogen peroxide solution into the acidic solution is used as the regenerating solution, metal impurities are dissolved in the regenerating solution and the impurity adsorbing plate 21a is used. ,
The desorption from 21b to the regeneration liquid can be effectively performed.

Further, in this embodiment, two impurity removing devices 9a and 9b are provided in parallel, and in step A, one impurity removing device 9a removes impurities, and at the same time, the other impurity removing device 9b is regenerated. Perform processing. Next, in step B, impurities are removed by the impurity removing device 9b,
At the same time, the other impurity removing device 9a is regenerated. The process A and the process B are alternately performed. That is, by alternately using the two impurity removing devices 9a and 9b in the circulation system of the cleaning liquid, the cleaning liquid 2 can be circulated during the regeneration treatment to continuously remove impurities, and the cleanliness of the cleaning liquid 2 can be improved. The cleaning device can be held and used continuously for a long time.

In the first embodiment, the cleaning device is provided with the two impurity removing devices 9a and 9b, but the cleaning device may be provided with three or more impurity removing devices and may be alternately used for the impurity removal. .

Further, although the suction plates 21a and 21b of the impurity removing devices 9a and 9b are formed in a comb shape, the suction plates 21a and 21b.
Even if the surface is made uneven to increase the contact area with the cleaning liquid 2, it is effective for removing impurities.

Further, in the above-described embodiment, the cleaning apparatus for cleaning the substrate 1 is used as the chemical processing apparatus, but a wet etching apparatus using an etching solution as the chemical also produces the same effect.

[0030]

As described above, according to the present invention, the chemical treatment device is provided with the mechanism for regenerating the impurity removing device.
It is possible to maintain the function of the impurity removing device, reduce the impurity concentration in the chemical liquid, and effectively prevent impurities from adhering to and contaminating the surface of the substrate to be processed such as the semiconductor substrate. Further, the chemical solution can be used for a long time, and the cost can be reduced.

Further, according to the present invention, since the filter is provided, it is possible to regenerate fine particulate impurities and metal impurities by removing particulate impurities having a particle diameter larger than the pore diameter of the filter from impurities in the chemical liquid. Since it is removed by a simple impurity removing device, impurities in the chemical solution can be removed efficiently.

Further, according to the present invention, a plurality of impurity removing devices are provided in parallel, and these are alternately used for the circulation system of the chemical liquid to remove impurities in the chemical liquid to remove the impurities in the chemical liquid and regenerate the impurity removing device. Since it is possible to process simultaneously with and, impurities can be continuously removed during the regeneration process, the cleanliness of the chemical liquid can be maintained, and the chemical liquid processing device can be continuously used for a long time.

Further, according to the present invention, since the mechanism for regenerating the impurity removing device is provided with the regenerating liquid supplying device and the pure water or air supplying device, the impurities adsorbed on the adsorption plate of the impurity removing device are regenerated liquid. Since it can be desorbed inside and the regeneration liquid can be replaced with pure water or air, regeneration treatment can be easily performed.

Further, according to the present invention, since an acidic solution or a solution obtained by mixing an acidic solution with an oxidizing agent is used as the regenerating liquid, the metal impurities can be dissolved in the regenerating liquid and the impurities adsorbed on the adsorption plate can be dissolved. It can be effectively released into the regenerating liquid,
Regeneration of the impurity removing device can be performed more reliably.

Further, according to the present invention, the impurity removing device is made of a conductive material and has two facing comb-shaped suction plates to which a voltage can be applied, and the comb teeth of the two comb-shaped suction plates. Since the plurality of plates corresponding to the contact part are alternately arranged, the contact area between the chemical solution and the part where the adsorption plate faces is increased, and the impurities can be effectively captured and removed.

Further, according to the present invention, since the surface of the adsorption plate is made uneven, the contact area between the chemical solution and the portion facing the adsorption plate is increased, and the impurities can be effectively captured and removed.

Further, in the chemical treatment method according to the present invention, when the regenerant is supplied, the adsorption plate of the impurity removing device is applied with a positive and negative electric potential opposite to that at the time of adsorbing the impurities. Therefore, desorption can be surely performed, and the regeneration treatment of the impurity removing device can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a chemical liquid processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of the impurity removing apparatus according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing a conventional cleaning device.

FIG. 4 is a configuration diagram showing a conventional impurity removing apparatus.

FIG. 5 is a graph illustrating a problem of a conventional cleaning device.

[Explanation of symbols]

2 Cleaning solution as chemical solution, 5 filters, 9a, 9b
Impurity remover, 10 Potential adjustment controller, 11
Regeneration liquid supply device, 12 pure water supply device, 13 air supply device, 20 cylindrical wall surface, 21a, 21b adsorption plate.

Claims (8)

[Claims] 1. An impurity for removing impurities in the chemical liquid by providing a mechanism for circulating the chemical liquid and a circulation system for the chemical liquid, and applying an electric potential to an adsorption plate made of a conductive material to adsorb the impurities. And a mechanism for separating the impurity removing device from the circulation system for the chemical liquid and desorbing the impurities adsorbed by the adsorption plate to regenerate the impurity removing device. . 2. The chemical liquid treatment apparatus according to claim 1, wherein a filter for removing particulate impurities in the chemical liquid is provided on the inlet side of the impurity removal device in the chemical liquid circulation system. 3. A plurality of impurity removing devices are provided in parallel, and the plurality of impurity removing devices are alternately used for a circulation system of the chemical liquid to remove impurities in the chemical liquid, and to remove impurities in the chemical liquid and the impurities. The chemical liquid treatment apparatus according to claim 1 or 2, wherein the removal apparatus can be regenerated at the same time. 4. A mechanism for regenerating the impurity removing device, a regenerator supply device for desorbing impurities adsorbed on the adsorption plate into the liquid, and a pure water or air supply device for replacing the used regenerant liquid. And 1 are provided.
3. The chemical treatment device according to any one of 3. 5. The chemical treatment apparatus according to claim 4, wherein an acidic solution or a solution obtained by mixing an oxidizing agent with the acidic solution is used as the regenerating liquid. 6. A chemical solution treating apparatus comprising a mechanism for circulating a chemical solution and an impurity removing apparatus for electrically adsorbing and removing impurities in the chemical solution, wherein the impurity treating apparatus comprises:
A chemical-resistant cylindrical wall surface and two opposing comb-shaped suction plates made of a conductive material and capable of applying a voltage are provided in the cylindrical wall surface. A chemical treatment apparatus, wherein a plurality of plates corresponding to the teeth of a comb of the plates are alternately arranged. 7. A chemical solution treating apparatus comprising a mechanism for circulating a chemical solution and an impurity removing apparatus for electrically adsorbing and removing impurities in the chemical solution, wherein the impurity removing apparatus is a chemical-resistant tubular shape. A chemical treatment apparatus having a wall surface and an adsorption plate made of a conductive material and capable of applying a voltage in the cylindrical wall surface, wherein the adsorption plate surface is uneven. 8. The chemical treatment method using the chemical treatment apparatus according to claim 4 or 5, wherein when the regenerant is supplied, the adsorption plate of the impurity removal apparatus is applied with an electric potential that is opposite to that at the time of adsorbing the impurities to adsorb them. The chemical treatment method is characterized in that the impurities that have been used are desorbed into the regenerant.