JPH05190523A - Washing device - Google Patents

Abstract

PURPOSE:To cut down the time required for temperature adjustment for washing chemical liquid used for washing of semiconductor wafers, for example. CONSTITUTION:The feeding holes of a chemical solution feeding tube 3 and a pure water feeding tube 4 are arranged on the upper part of a washing treatment vessel 1 provided with a wafer retaining member 2 which can be freely moved vertically. A pure water tank 5 is connected to the inlet side of the pure water feeding tube 4. A heater 6 and an air feeding tube 7, with which nitrogen gas is fed, are provided in the tank 5, and at the same time, liquid level detecting parts 52 and 53, with which pure water is weighed, are arranged on the upper and the lower parts of the tank. After the prescribed quantity of pure water of room temperature has been introduced into the tank 5, the tank is heated up by a heater 6, bubbles are generated, and pure water is fed to a washing treatment vessel 1 after the set temperature is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductor devices,
Various films such as semiconductor layers, insulating layers, and electrode layers are laminated, but when other layers are formed on the surface of a certain layer, residues such as particles during film formation, unnecessary particles such as heavy metals, etc. intervene in a predetermined amount. Therefore, in order to prevent these particles from being incorporated into the device, the wafer is cleaned with a chemical solution during the film forming process, for example.

As an apparatus for performing such cleaning, for example, a holding member for holding a large number of wafers, a cleaning treatment tank provided with a heating means, and a chemical liquid tank storing an alkaline or acid chemical liquid. And a pure water tank for storing pure water for diluting the chemical liquid to set a predetermined concentration. Then, in order to clean the wafer, a predetermined amount of the chemical liquid is injected from the chemical liquid tank into the cleaning treatment tank, and a predetermined amount of pure water is injected from the pure water tank to mix the chemical liquid and the pure water in the cleaning treatment tank. The cleaning liquid is heated by a heating means while being circulated to adjust the temperature to a predetermined temperature, and then the wafer is held in a holding member and immersed in the cleaning liquid for cleaning. Here, the cleaning solution is heated from room temperature to,
Since it takes a long time to raise the temperature to about 90 ° C., one simple method is to previously heat pure water to a temperature slightly higher than the predetermined temperature of the cleaning liquid by the heater in the pure water tank. It has also been practiced to mix heated pure water and a chemical solution in a cleaning treatment tank so that the temperature of the cleaning solution rises faster.

[0004]

By the way, since a large number of processing stations and transfer systems are generally concentrated in a wafer manufacturing factory, it is necessary to make each processing station as compact as possible. In addition to such a situation, the cleaning device is usually provided with a plurality of cleaning treatment tanks to which different chemicals are respectively supplied, and a rinse tank is arranged between these cleaning treatment tanks. Various measures have been taken to reduce the area occupied by the unit. For example, the deionized water tank also has a structure with a small bottom area and a large height. In this case, even if the upper layer of the deionized water tank is heated to the set temperature when the heater is heated,
The temperature of the lower layer is much lower than the set temperature.Therefore, when the upper layer reaches the set temperature, even if the pure water is supplied to the cleaning treatment tank and mixed with the chemical solution, the temperature of the entire pure water rises and falls. Since there is a large temperature difference in
After all, it is not possible to sufficiently shorten the time for adjusting the temperature of the cleaning liquid in the cleaning treatment tank. In particular, as the wafer size increases from 6 inches to 8 inches in the future, the cleaning processing tank and the deionized water tank also increase in size, so the cleaning temperature adjustment time becomes longer and throughput increases. It will hinder improvement.

It is also possible to adopt a structure in which a pure water tank is provided with a circulation path equipped with a pump, but in this case, the structure of the pure water tank and its surroundings becomes complicated, and the structure described above is adopted. As described above, the purpose of shortening the temperature adjustment time of the cleaning liquid by a simple method is largely deviated.

The present invention has been made under such circumstances, and an object thereof is to provide a cleaning device which can shorten the temperature adjustment time of the cleaning liquid by a simple method.

[0007]

According to a first aspect of the present invention, there is provided a cleaning apparatus comprising a mixed solution of a chemical solution and a diluting solution, the cleaning solution having a temperature adjusted and brought into contact with an object to be cleaned,
A temperature adjusting means for adjusting the temperature of the diluent and a bubbling means for forming bubbles in the diluent are provided.

According to a second aspect of the present invention, there is provided a cleaning apparatus for contacting and cleaning an object to be treated with a temperature-controlled cleaning liquid consisting of a chemical liquid and a diluting liquid from a diluting liquid tank. A heating means is provided in the area, and the heating means forms a convective liquid flow between the partial area and the other area of the bottom surface portion where the heating means is not arranged.

[0009]

According to the first aspect of the invention, the diluent is supplied by supplying a predetermined amount of the diluent at room temperature into the diluent tank, heating the diluent by the temperature adjusting means such as the heating means and bubbling by the bubbling means. Is heated because it is stirred.

According to the second aspect of the present invention, when the heating means is turned on by supplying a predetermined amount of the diluent at room temperature into the diluent tank, the heated diluent rises, and the heating means is arranged. The diluting liquid in the diluting liquid tank is uniform because the diluting liquid having a low temperature flows from the region in which the heating means is not arranged to the heating means side while flowing laterally toward the unheated area, thereby forming convection. Is heated to. Therefore, for example, when the upper layer of the diluting liquid reaches the set temperature, the chemical liquid and the diluting liquid are supplied into the cleaning treatment tank and heated while being mixed,
Since the temperature of the entire diluting liquid is high, the temperature adjustment of the cleaning liquid in the cleaning treatment tank becomes short. After that, the object to be processed is immersed in the cleaning liquid for cleaning.

[0011]

EXAMPLE An example in which the present invention is applied to a semiconductor wafer cleaning apparatus will be described below.

(Embodiment 1) FIGS. 1 and 2 are a perspective view and a vertical sectional front view showing an outline of Embodiment 1 of the present invention, respectively. In the figure, reference numeral 1 denotes a cleaning tank for cleaning a semiconductor wafer as an object to be processed with a cleaning liquid composed of a mixed liquid of a chemical liquid and pure water, which will be described later, and an upper edge thereof overflows (overflow). An overflow tank 11 is provided outside the upper edge so as to surround the entire circumference. In the cleaning processing tank 1, a holding member 2 having three holding arms 21 is vertically movable by an elevating mechanism (not shown) so as to hold a large number of wafers W vertically arranged side by side. A heating means (not shown), which is a temperature adjusting means, is provided while being disposed. Between the bottom of the cleaning treatment tank 1 and the bottom of the overflow tank 11, a circulating water passage 12 including a quartz glass tube, a flexible resin tube, and the like and having a pump P is connected as shown in FIG. Therefore, the cleaning liquid is circulated by the circulating water passage 12.

At the upper part of the cleaning treatment tank 1, there are arranged supply ports for a chemical liquid supply pipe 3 and a pure water supply pipe 4 each made of, for example, a quartz glass pipe, and the inlet side of the chemical liquid supply pipe 3 is shown in FIG. As described above, the valve V1 is connected to the chemical liquid tank 31 for storing the chemical liquid consisting of hydrochloric acid and hydrogen peroxide solution, and the inlet side of the pure water supply pipe 4 is used as a diluting liquid via the valve V2. It is connected to a pure water tank 5 which constitutes a diluting liquid tank for storing pure water.

In the pure water tank 5, a heater 6 as a temperature adjusting means is formed by inserting a nichrome wire into a glass tube.
Is arranged near the bottom surface, and an air supply pipe 7 made of, for example, a quartz glass pipe is installed as a bubbling means in which the gas outlet is located near the bottom portion. The air supply pipe 7 is provided with, for example, nitrogen gas through a valve V3. It is connected to the supply source 71. Further, one end of a water supply pipe 51 for supplying pure water into the tank 5 is connected to the bottom of the pure water tank 5, and the other end of the water supply pipe 51 is connected to the inside of the factory via a valve V4. It is connected to the pure water supply system.

A temperature detector T for detecting the water temperature near the upper layer is provided in the pure water tank 5, and it is detected that a predetermined amount of pure water from the water supply pipe 51 is stored. In order to detect that the discharge amount from the pure water supply pipe 4 (supply amount to the cleaning treatment tank 1) has become constant,
Liquid level detectors 52 and 53 are provided on the upper and lower sides, respectively, thereby providing a weighing function. The temperature detection unit T and the liquid level detection units 52 and 53 are connected to a control unit C (see FIG. 2) for controlling the valves V2 to V4 and the like based on detection signals from these.

Next, the operation of the first embodiment will be described.
First, when the valve V4 is opened from the deionized water supply system in the factory and pure water at room temperature is introduced into the deionized water tank 5 through the water supply pipe 51, when the liquid level reaches the detection position of the upper liquid level detection unit 52. The valve V4 is closed and a predetermined amount of pure water is stored in the tank 5. The pure water is heated by the heater 6, and nitrogen gas is supplied from the nitrogen gas supply source 71 into the pure water through the air supply pipe 7 to form bubbles. As a result, the bubbles rise and circulate vertically. A liquid flow is generated, and the pure water is uniformly heated from the upper layer portion to the lower layer portion. When the temperature of the pure water becomes slightly higher than the set temperature of the cleaning liquid, for example, when the set temperature of the cleaning liquid is 80 ° C. and the temperature of the pure water reaches 85 ° C., the valve of the pure water supply pipe 4 V
Open 2 to wash pure water at 85 ℃ from tank 5
And the liquid level in the tank 5 is lower than the liquid level detection unit 53.
When the detection position is reached, the valve V2 is closed, so that a predetermined amount of pure water is supplied into the cleaning treatment tank 1.

In this embodiment, when a certain amount of pure water is introduced into the pure water tank and a certain amount of pure water is discharged, if bubbling is performed, the liquid level may fluctuate and the weighing accuracy may be deteriorated. As shown in FIG. 3, bubbling is stopped during weighing, and bubbling is performed only during temperature adjustment.

On the other hand, from the chemical solution tank 31, a cleaning solution tank 1 is supplied with a room temperature chemical solution, for example, a mixed solution of hydrochloric acid and hydrogen peroxide, and the pump P is driven to drive the pure water and the chemical solution. The mixed solution of and is overflowed from the upper edge into the overflow tank 11 and returned to the bottom of the cleaning treatment tank 1 through the circulation path 12. Thus, the pure water and the chemical solution are mixed and heated by a heater (not shown) to raise the temperature to a set temperature, for example, 80 ° C., and maintain this temperature. After that, when the cleaning liquid in the cleaning processing bath 1 reaches the set temperature, the holding member 2 is lowered at the upper limit position after receiving the wafer W from the transfer arm (not shown), and as a result, the wafer W is immersed in the cleaning liquid to form the cleaning liquid. Contacted and washed. Then, the wafer W is transferred from the holding member 2 to the transfer arm by the reverse operation, and rinsed with, for example, pure water. Then, the cleaning liquid in the cleaning processing tank 1 is replaced every time a predetermined number of wafers are cleaned, for example, several times a day. At the time of exchanging the cleaning liquid, the temperature of the cleaning liquid is adjusted in the same manner after cleaning the inside of the cleaning treatment tank 1 with pure water, for example.

Here, in the cleaning treatment tank 1, 3.9 l of hydrochloric acid,
In order to investigate the effect of the device of the present invention on the process of mixing 3.9 liters of hydrogen peroxide water and 19.3 liters of pure water and setting the temperature of the cleaning liquid, which is the mixture, to 80 ° C., the following model experiment was conducted. I went. That is, the room temperature (25
While injecting 7.8 liters of pure water (° C.) into the cleaning treatment tank 1,
When pure water at room temperature is stored in the pure water tank 5 and heated by the heater 6 to bring the temperature of the temperature detecting portion T to a set temperature, 19.3 l of pure water is washed from the pure water tank 5 to the cleaning treatment tank 1 The temperature of the pure water tank 5 and the temperature change of the cleaning treatment tank 1 were examined for each of the following conditions.

(Condition A) The set temperature of the pure water tank 5 is set to 80
No bubbling (conventional method).

(Condition B) The set temperature of the pure water tank 5 is set to 80.
℃, nitrogen gas flow rate and pressure 1Nl / min and 1
Bubbling is performed at atmospheric pressure.

(Condition C) The set temperature of the pure water tank 5 is set to 90.
℃, nitrogen gas flow rate and pressure 1Nl / min and 1
Bubbling is performed at atmospheric pressure.

(Condition D) The set temperature of the pure water tank 5 is set to 95.
℃, nitrogen gas flow rate and pressure 1Nl / min and 1
Bubbling is performed at atmospheric pressure.

FIGS. 4 and 5 are characteristic diagrams showing the temperature of the upper layer portion (solid line) and the temperature of the lower layer portion (dotted line) in the pure water tank 5 under the conditions A and B, respectively. As can be seen from this result, in the conventional device without bubbling, a temperature difference of about 40 ° C. occurs between the upper layer portion and the lower layer portion, whereas in the device of the present invention, there is almost no temperature difference.

FIG. 6 shows the water temperature in the cleaning treatment tank 1,
A to D are data corresponding to the conditions A to D, respectively. The time shown in the figure is the temperature rising time up to the allowable temperature when the temperature of the cleaning liquid is set to 80 ° C. Since both A and B set the temperature of the pure water tank 5 to 80 ° C., it can be understood that the temperature rising time can be shortened from 39 minutes to 23 minutes by bubbling. Further, it can be seen that the temperature rising time is shortened to 20 minutes and 18 minutes by increasing the set temperature in the pure water tank to 90 ° C and 95 ° C.
As described above, according to the first embodiment, the temperature of the pure water in the pure water tank 5 is uniformly adjusted by the bubbling, so that the time for adjusting the temperature of the cleaning liquid can be shortened and the technique of bubbling can be achieved. Since bubbles are applied to the pure water tank, no bubbles are generated in the cleaning treatment tank 1, and bubbles generated when bubbling is performed in the cleaning treatment tank 1 adhere to the wafer surface, and the bubbles locally cause the bubbles. It is extremely effective in that it does not adversely affect the cleaning process. For bubbling, other gas such as air may be used instead of nitrogen gas, and instead of using one air pipe, a diffuser plate having a large number of holes is arranged at the bottom of the diluting liquid tank. Good.

(Embodiment 2) FIG. 7 is a perspective view showing a deionized water tank used in Embodiment 2 of the present invention. This embodiment has substantially the same structure as that of Embodiment 1, but as a bubbling means. The difference is that a heater is arranged in a half region on one side of the pure water tank instead of installing the air supply pipe 7.
Reference numeral 5 in FIG. 7 denotes a pure water tank, and the bottom surface of the pure water tank 5 is bent so as to form an inclined surface that rises from near the central portion toward the left side surface in the drawing. A nichrome wire is inserted into a glass tube in the pure tank 5, and a heater 6 as a heating means formed in, for example, a U shape corresponds to a partial area of the bottom surface portion, for example, a horizontal bottom surface. A temperature detection unit T for detecting the water temperature near the upper layer is provided in the right half region, and a pure water supply pipe 4 is connected to the horizontal bottom surface. Next, the operation of the above-described second embodiment will be described. When pure water at room temperature is introduced into the pure water tank 5 and the heater 6 is turned on in the same manner as in Example 1, the pure water in the vicinity of the heater 6 is heated and rises to the upper layer portion. The upper layer portion is moved laterally toward the area where the heater 6 is not arranged, that is, the area above the inclined surface, and the pure water on the area where the heater 6 is not arranged, that is, the inclined surface is The pure water that has moved along the inclined surface to the vicinity of the heater 6 and has moved to the vicinity of the heater 6 is heated in the same manner as described above. Water convection occurs. Then, when the temperature of the pure water becomes slightly higher than the set temperature of the cleaning liquid, the pure water is washed by a predetermined amount by the same operation as in the first embodiment based on the detection signal from the temperature detection unit T.
Meanwhile, the chemical solution is supplied from the chemical solution tank 31 into the cleaning treatment tank 1, and the wafer W is cleaned in the same manner as in Example 1.

Here, the temperature distribution in the pure water tank 5 is examined for the case where the heater 6 is arranged in a partial area of the bottom surface of the pure water tank 5 and the case where the heater 6 is arranged over the entire area. Therefore, the following experiment was conducted.

First, as shown in FIG. 8A, in a pure water tank 5 according to the present embodiment, for example, the length (vertical direction to the paper surface) horizontal and height dimensions are about 25 cm, 38 cm and 37 cm, respectively. , The heater 6 is arranged such that the tip of the U-shaped portion is located at the lateral center of the pure water tank 5.
After introducing pure water at room temperature, the temperature is set to 80 ° C., the heater 6 is turned on, and the upper layer portions at the left and right ends in FIG.
The temperature change was examined at a total of four places in the lower layer. The experimental results are as shown in FIG. 9, and the temperature change at any of the above measurement points was within the zone indicated by the diagonal lines in FIG.

On the other hand, as shown in FIG. 8B, the length (vertical direction to the paper surface), the width, and the height are approximately 32 cm and 32, respectively.
In the pure water tank 5a of cm and 23 cm, the heater 6 was arranged over the entire bottom surface portion, and similarly, the temperature change was examined at two places of the upper layer portion and the lower layer portion. The experimental results are as shown in FIG. 10, and the solid line and the broken line in FIG. 10 are curves showing the temperature changes of the upper layer portion and the lower layer portion in the pure water tank 5a, respectively.

As can be seen from the results of these experiments, FIG.
When the pure water tank 5 of the cleaning apparatus according to the present embodiment shown in (a) is used, the pure water in the pure water tank 5 is heated uniformly, while the comparison shown in FIG. When the pure water tank 5a of the example is used, a large temperature difference of about 40 ° C. occurs between the upper and lower layers of pure water in the pure water tank 5a. This is as shown in FIG.
As shown in (a), a convection of pure water is smoothly formed in the direction of the arrow in the entire tank, but in the pure water tank 5a, the convection is pure.
It is considered that the pure water heated in the vicinity of the water 6 hardly moves in the lateral direction after rising, so that convection of pure water is less likely to be formed in the pure water tank 5a. In addition, the pure water tank 5
However, since the inclined surface is formed on the bottom surface of the area where the heater 6 is not arranged, pure water flows along the inclined surface from the area, so that convection is further smoothed. When the pure water in the pure water tank 5 is drained from the pure water supply pipe 4, the pool of water on the bottom surface of the pure water tank 5 is reduced. As described above, according to the pure water tank 5 according to the present embodiment, the temperature of the pure water in the pure water tank 5 is uniformly adjusted in a short time, so that the time for adjusting the temperature of the cleaning liquid can be shortened. it can.

The deionized water tank 5 according to the present embodiment is not limited to the shape shown in FIG. 7, and the heating means may be arranged in a partial area instead of being arranged over the entire bottom surface of the deionized water tank 5. The configuration may be such that sufficient convection is formed by, for example, FIG.
As shown in 1, the bottom surface of the pure water tank is formed with an inclined surface that inclines from the horizontal surface of the central part to both sides, and by installing a heater on the horizontal bottom surface of the central part, convection is formed on both left and right sides. It may have any configuration. Further, the shape of the heater is not limited to the U shape, and may be, for example, an M shape.

Further, the structure of the pure water tank according to this embodiment is not limited to that shown in FIGS. 7 and 11, but a bubbling means such as an air supply pipe for stirring the pure water in the pure water tank is provided. May be

Next, FIG. 12 shows an example of a part of a cleaning system to which the cleaning device of the present invention is applied. In this system, a carrier loading table 92 (in this figure, the carrier is placed on the loading table 92) of the carrier that stores the wafer and the wafer in the carrier are pushed up to the wafer loading section 91 and the transfer arm 93 is pushed.
A push-up unit 94 for delivering to the wafer, a cleaning processing tank 95 for cleaning with the above-described cleaning liquid, a rinse tank 96 for rinsing with pure water, and an underwater transfer unit 97 are provided, and the wafer transfer arm 93 is provided. Are successively transported to the cleaning treatment tank 95 and the rinse tank 96, and are further transported to another cleaning treatment tank (not shown) by the underwater transport unit 97. When the number of cleaning treatment tanks is large as described above, the application of the present invention is very effective.

In the above, the present invention is not limited to pure water as the diluting liquid, and the temperature may be adjusted by cooling instead of heating.

The object to be processed is not limited to a semiconductor wafer, but may be a glass substrate or LCD substrate.

[0036]

According to the first aspect of the invention, the temperature is adjusted while bubbling the diluting liquid in the diluting liquid tank, and according to the second aspect of the invention, the diluting liquid tank Since the diluting liquid forms a convection, the temperature of the diluting liquid is uniformly adjusted in any of these inventions. Therefore, it is possible to shorten the time required for the temperature adjustment of the mixed liquid of the diluting liquid and the chemical liquid by a simple method. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a main part of the first embodiment.

FIG. 3 is a flowchart showing the timing of bubbling in the first embodiment.

FIG. 4 is a characteristic diagram showing a temperature change in a pure water tank in the conventional example of the first embodiment.

FIG. 5 is a characteristic diagram showing a temperature change in the pure water tank according to the first embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a temperature change in the cleaning treatment tank for the conventional example and the first example.

FIG. 7 is a perspective view showing an example of a pure water tank according to a second embodiment of the present invention.

FIG. 8 is a vertical sectional view showing a pure water tank according to the second embodiment and a pure water tank according to a comparative example.

FIG. 9 is a characteristic diagram showing a temperature change in a pure water tank according to a second embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a temperature change in a pure water tank in the conventional example of the second embodiment.

FIG. 11 is a vertical cross-sectional view showing another example of the pure water tank according to the second embodiment of the present invention.

FIG. 12 is a plan view showing an example of a cleaning system to which the present invention is applied.

[Explanation of symbols]

 1 Cleaning Treatment Tank 2 Holding Member 3 Chemical Solution Supply Pipe 4 Pure Supply Pipe 5 Pure Tank 6 Heater 7 Air Pipe

Claims (2)

[Claims] 1. A cleaning apparatus comprising a mixed solution of a chemical solution and a diluting solution, wherein the object to be treated is brought into contact with a temperature-controlled cleaning solution, and a temperature adjusting means for adjusting the temperature of the diluting solution is provided, A cleaning device comprising bubbling means for forming bubbles in the diluent. 2. A cleaning apparatus for cleaning an object to be treated by contacting a temperature-controlled cleaning liquid comprising a chemical liquid and a diluent from a diluent tank with a heating means in a partial area of the bottom surface of the diluent tank. A cleaning apparatus, which is provided and forms a liquid flow by convection between the partial region and the other region of the bottom face portion where the heating unit is not provided by the heating unit.