JPH04196535A - Cleaning equipment - Google Patents

Abstract

PURPOSE:To exclude influence of dust and the like generated at the time of operating a pump upon an object to be processed, by installing a treatment liquid tank which is arranged at a position where a treatment liquid supply port is higher than a cleaning treatment tank, stores treatment liquid, and makes the treatment liquid drip into the cleaning treatment chamber by the effect of self-weight. CONSTITUTION:A constant amount of cleaning treatment liquid 68 is supplied from a treatment liquid tank 60 to a cleaning treatment tank 26, 30, in the manner in which the total amount of liquid in the treatment liquid tank 60 is supplied through a quartz tube 60C by self-weight drop caused by head difference. This supply is executed before a semiconductor wafer is dipped into the tank 26, 30. The temperature of the treatment liquid in the tank 26, 30 in controlled, and set at a specified value, and then the semiconductor wafer is dipped in the treatment liquid. A pump 62 is connected with a large storage tank 72 which contains the cleaning treatment liquid such as ammonia and hydrofluoric acid. From the storage tank 72, the cleaning treatment liquid is pressurized, sent, and supplied to the treatment liquid tank 60. The pump 62 and the storage tank 72 are arranged in positions distant from the cleaning treatment tank 26, 30, and in an isolated state from the cleaning equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a cleaning device, and particularly to an improvement in a method for supplying processing liquid to a cleaning processing tank.

(Prior Art) An example of this type of cleaning apparatus is a cleaning apparatus used in a semiconductor wafer manufacturing apparatus.

In this cleaning device in a semiconductor wafer manufacturing apparatus, an object to be processed is placed in a cleaning tank, and a processing liquid is supplied into the cleaning tank to perform the cleaning process.

In this case, if pure water is used as the cleaning treatment liquid, the factory is equipped with a pure water supply system, so the pure water supply system is used to supply pure water into the cleaning treatment tank. .

On the other hand, if a chemical solution such as hydrofluoric acid (HF) or ammonia that cannot be supplied at a factory is used as a cleaning treatment liquid, a pump to supply the chemical solution is installed near the cleaning treatment tank. A pump was used to pump the cleaning solution into the cleaning tank.

(Problems to be Solved by the Invention) Generally, in the manufacture of VLSIs, the manufacturing process must be performed in a clean atmosphere in order to improve product quality and product yield. If the above-mentioned in-factory supply system for pure water or the like can be used, it is possible to maintain a clean atmosphere.

On the other hand, if a chemical solution such as hydrofluoric acid (HF) or ammonia is used as a cleaning treatment liquid, for which the in-factory supply system as described above cannot be used, a pump is required to pressure-feed the cleaning treatment liquid. Moreover, this pump cannot be expected to be fully effective unless it is placed near the cleaning treatment tank.

However, when the pump is operated, dust is generated due to the operation of the pump, causing contamination of the above-mentioned clean atmosphere, resulting in a problem in that the quality of semiconductor wafers and the yield are lowered.

If the pump is moved away, the piping from the pump to the processing tank becomes long, resulting in increased pressure loss and reduced supply efficiency.

In addition, since the storage of the cleaning solution supplied to the cleaning treatment tank was dependent only on the pump, errors in the amount of cleaning solution supplied by the pump were likely to occur, and errors could accumulate, causing the cleaning There is a problem that processing liquid is wasted, and this problem becomes more pronounced as the pump is moved farther from the processing tank.

Therefore, the present invention prevents contamination of a clean atmosphere by a pump and accurately weighs the supplied processing liquid when using a chemical liquid as a processing liquid for which the supply system such as a processing liquid in a factory cannot be used. The problem to be solved is to provide a cleaning device that can do the following.

[Structure of the Invention] (Means for Solving the Problems) The cleaning apparatus of the present invention includes a cleaning treatment tank in which an object to be treated is provided and the object to be treated is treated with a chemical, and a treatment liquid supplied from the cleaning treatment tank. The present invention is characterized in that it is provided with a processing liquid tank whose opening is provided at a high position, and which stores the processing liquid and allows the processing liquid to drop under its own weight into the cleaning processing tank.

(Function) The cleaning device of the present invention having the above configuration uses a pump to supply the treatment liquid to the treatment liquid tank disposed at a higher position than the cleaning treatment tank, stores the treatment liquid in this treatment liquid tank, and stores the treatment liquid in the treatment liquid tank. When a predetermined amount has been reached, the treatment liquid is dropped from the treatment liquid tank into the cleaning treatment tank by its own weight.

In this case, the processing liquid is supplied to the cleaning processing tank from the processing liquid tank using its own weight, so the processing liquid is simply supplied from the pump to the processing liquid tank. It is only necessary to store the liquid, and therefore the pump can sufficiently supply the processing liquid even when the pump is located far from the processing liquid tank.This eliminates the influence of dust, etc. generated when the pump is operating on the object to be processed. It is possible to contribute to improving product quality and yield.

(Example) Hereinafter, an example in which the present invention is applied to a cleaning device in a semiconductor wafer manufacturing apparatus will be described with reference to the drawings.

In FIG. 1, the semiconductor wafer cleaning apparatus of this embodiment is constructed by combining three cleaning processing units 10.12.14. Further, a loader 16 is connected to the processing unit 10 on the carry-in side, an unloader 18 is connected to the processing unit 14 on the carry-out side, and further between the cleaning processing units 10 and 12 and between the cleaning processing units) 12 and 14. , an underwater loader 20 included in any of the three units is disposed.

The cleaning processing unit 10 on the carry-in side has a rotary conveyance arm 24 for conveying semiconductor wafers 22 disposed at the center position, and the front side of the loader 16 and the rotary conveyance arm 24 are arranged around it.
Two cleaning tanks 26 and 28 are arranged on the left side of each tank. In this embodiment, the cleaning process 1126
is used as a chemical treatment tank for ammonia treatment, and the cleaning treatment tank 28 is used as a quick dump rinse (QDR) treatment tank for water washing.

The central cleaning processing unit 12 has underwater loaders 20 positioned on both left and right sides around a rotary transfer arm 24 disposed at the center, and two cleaning processing tanks 3 each at the front and rear positions between them.
0.32 is set. In this embodiment, the cleaning treatment tank 30 is used as a chemical treatment tank for performing hydrofluoric acid treatment, and the cleaning treatment tank 32 is used as a water washing overflow treatment tank.

The cleaning processing unit 14 on the unloading side has a cleaning tank 34 disposed on the front side of the unloader 18 around the rotary transport arm 24 arranged at the center position, and
A drying treatment tank 36 is disposed on the right side of the drying tank 4.

In this embodiment, the cleaning treatment tank 34 is used as a final rinse tank. In addition, each processing tank 26.28.
30°, 32, 34, and 36 are arranged in independent cases, as shown in FIG. 2, for example.

When the 25 semiconductor wafers 22 placed on each of the two carriers 48 are transferred to the loader 16, the orientation flats of the semiconductor wafers 22 are aligned on the loader 16 by a so-called orientation flat alignment mechanism. The semiconductor wafer 22 is lifted and brought together by the pushing up mechanism.

Next, the rotary transfer arm 24 operates to take out only the semiconductor wafer 22 from the loader 16 and transfer it to the cleaning treatment tank 26.
After only the semiconductor wafers 22 are transferred to and subjected to cleaning processing, the semiconductor wafers 22 are received from the cleaning processing tank 26 and sent to the cleaning processing tank 28 and the underwater loader 20, where they are sequentially subjected to the cleaning processing.

Thereafter, the cleaning treatment tank 30,
32, underwater loader 2o cleaning treatment tank 34, drying treatment tank 36
The semiconductor wafers 22 are transferred to the unloader 18, where they are subjected to cleaning or drying processing, and then transferred to the unloader 18, where the semiconductor wafers 22 are
It is designed to be loaded and carried out in two carriers 48.

In addition, a cleaning treatment tank 28 that performs quick dump and rinse
．． The underwater loader 20, the washing overflow treatment tank 32, and the cleaning treatment tank 34 that performs the final rinse process use pure water as the cleaning liquid, and this pure water is supplied to a pure water supply installed in advance in the factory. It is supposed to use what is provided by the system.

Then, a cleaning treatment tank 26 for ammonia treatment using ammonia or hydrofluoric acid (HF) as a cleaning treatment liquid and a cleaning treatment for hydrofluoric acid treatment without using pure water using a pure water supply system installed in advance in the factory. As shown in FIG. 3, the tank 30 includes a processing liquid tank 6 which stores a cleaning processing liquid such as ammonia or hydrofluoric acid at a higher position than the cleaning processing tank 26.30.
0 is provided, and the cleaning treatment liquid is supplied to this tank 60 by a pump 62 that pumps and supplies it.

The processing liquid tank 60 is provided with a liquid level detection sensor 66 at an upper position inside thereof for detecting the liquid level position of the cleaning processing liquid 64 supplied into the processing liquid tank 60 by the pump 62. Of the liquid amount detected by the liquid level detection sensor 66 at the bottom of the cleaning processing tank 26
, 30, and includes a drain 68 having a valve 70 for discharging to the outside excess cleaning liquid 64 exceeding a predetermined amount of liquid required for processing in the sensor 6.
It is opened and closed based on the signal No. 6. That is, the drain 68
When the amount of liquid detected by the liquid amount detection sensor 66 exceeds a predetermined amount, the valve 70 is opened and the excess cleaning liquid 64 can be discharged.

Specifically, after the liquid level detection sensor 66 detects the cleaning liquid 64, the pump 62 stops pumping and supplying the cleaning liquid 64, for example, after about two seconds have elapsed.

Then, the valve 70 having a small-diameter orifice is opened to discharge the cleaning processing liquid 64 in the processing liquid tank 60 through the drain 68, and the discharging is stopped at the position where the liquid level detection sensor 66 no longer detects the liquid. By doing so, it is possible to accurately weigh the cleaning treatment liquid 64 in the treatment liquid tank 6°. The above discharge amount is, for example, usually the cleaning treatment liquid 64
The amount is approximately several tens of ml per 3 g, and the discharge frequency is approximately once per six batch processes.

That is, the entire amount of the accurately weighed cleaning treatment liquid 64 in the treatment liquid tank 6o is supplied to the cleaning treatment tank 26.30. After this supply, the cleaning treatment liquid 64 is supplied under pressure to the treatment liquid tank 60, but at this time, the above-mentioned accurate weighing does not need to be carried out.

Then, the semiconductor wafer 22 is immersed in the cleaning tanks 26 and 30 for cleaning treatment. As the cleaning process is repeated, the amount of the cleaning solution 64 in the cleaning tank 26, 30 gradually decreases, and when replenishment is required, the amount of processing liquid in the processing liquid tank 60 is increased by, for example, a metering pump (not shown). A portion of the water is appropriately supplied under pressure to the cleaning treatment tanks 26 and 30 to replenish it.

After repeating the above cleaning process, for example, six cycles (six batch processes), the cleaning solution in the cleaning tank 26.30 is discarded in order to be replaced with a new solution. At the time of this exchange, the discharge as described above is performed, and an accurately weighed new solution (cleaning treatment liquid 64) is supplied to the cleaning treatment tank 26.30.

Note that the liquid amount detection sensor 66 is composed of, for example, a capacitance sensor.

In addition, the ceiling of the processing liquid tank 60 is configured to be able to communicate with the outside via a filter 6OA, and prevents the inside of the processing liquid tank 60 from becoming negative pressure, for example, when the cleaning processing liquid 64 decreases. .

On the other hand, at the bottom of the processing liquid tank 60, there is a nozzle for supplying the cleaning processing liquid 64 to the cleaning processing tank 26.30 via a chemical-resistant, low-dust generation type air operated valve 60B, for example, a liquid is installed on the inner surface. A quartz tube 60C with a smooth surface that does not cause stagnation is attached.

Then, from the processing liquid tank 60 to the cleaning processing tank 26.3.
The cleaning processing liquid 64 is supplied as a fixed amount from the quartz tube 60C either by the entire amount in the processing liquid tank 60 or by falling under its own weight due to the water head difference of the liquid in the processing liquid tank 60.

This supply supplies the semiconductor wafer 22 to the cleaning treatment tank 26.30.
After that, the cleaning treatment tank 26.30
After controlling the temperature of the processing liquid therein and setting it at a set temperature, the semiconductor wafer 22 is immersed in the processing liquid.

The pump 62 is connected to a large storage tank 72 that accommodates a cleaning treatment liquid such as ammonia or hydrofluoric acid, and the storage tank 72 pumps and supplies the cleaning treatment liquid into the treatment liquid tank 60. .

Further, the pump 62 and the storage tank 72 are located apart from the cleaning treatment tank 26, 30, and are isolated from the cleaning device.

For example, the pump 62 and storage tank 72 can be placed in a completely isolated location by using cleaning treatment tanks 26, 30 made of highly chemical-resistant materials and by flowing clean downflow from above through HEPA filters. It is located.

Although not shown, pure water is also supplied to the tank by falling under its own weight after accurate weighing using a liquid amount detection sensor in the same manner as for supplying the processing liquid.

In this way, the cleaning treatment liquid in the storage tank 72 is pumped and supplied into the treatment liquid tank 60 by the pump 62, and the cleaning treatment liquid is temporarily stored in the treatment liquid tank 60, so that the pump 62 can be used accurately. There is no need to provide a storage detection function, and the pump 62 is used only for supplying the cleaning processing liquid, so that the pump 62 can be placed separately from the cleaning processing tank 26, 30, and the amount of water generated from the pump 62 during the washing processing can be removed. It is possible to prevent the clean atmosphere from being contaminated by dust and to prevent it from affecting the semiconductor wafer 22.

In addition, a liquid level detection sensor 66 provided in the processing liquid tank 60 detects the processing liquid level corresponding to the amount required for one cleaning operation, and the excess processing liquid is discharged from the drain 68. , it is possible to accurately set the storage of a predetermined processing liquid without depending on pump accuracy, and it is possible to eliminate waste of cleaning processing liquid.

Furthermore, by dropping the cleaning treatment liquid from the treatment liquid tank 60 under its own weight into the cleaning treatment tanks 26 and 30 after obtaining accurate storage, the cleaning treatment can be performed in a bombless state, and unnecessary dust generation can be avoided. This can be prevented.

Since the liquid level detection sensor detects the level position of the processing liquid equivalent to the amount required for one cleaning operation, accurate deposition of processing liquid can be obtained without depending on pump accuracy. This has the effect of eliminating waste of processing liquid.

[Effects of the Invention] As explained above, the cleaning device of the present invention uses a pump to supply the treatment liquid to the treatment liquid tank disposed at a higher position than the cleaning treatment tank, and the cleaning treatment is carried out from this treatment liquid tank. Because we decided to supply the processing liquid by dropping it into the tank under its own weight,
By installing the pump at a location separate from the cleaning treatment tank, the treatment liquid can be supplied from the treatment liquid tank to the cleaning treatment tank using a bomb press, and as a result, the treatment atmosphere can be maintained in a clean atmosphere. This has the effect of improving product quality and yield.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the overall configuration of a cleaning device according to an embodiment of the present invention, FIG. 2 is a perspective view showing the state of the cleaning treatment tank in FIG. 1, and FIG. 3 is a cleaning treatment tank and treatment It is a block diagram which shows the state of a liquid tank and a pump. 26.30...Cleaning treatment tank, 60...Processing liquid tank, 62...Pump, 64...
- Processing tank, 66...Liquid level detection sensor, 68...Drain. Agent Patent attorney Inoue - (1 other person) Figure 2

Claims (1)

[Scope of Claims] A cleaning treatment tank in which an object to be treated is provided and the object to be treated is treated with a chemical; a treatment liquid supply port is provided at a higher position than the cleaning treatment tank, and the treatment liquid is stored in the cleaning treatment tank and the treatment liquid is stored in the cleaning treatment tank. A cleaning device characterized in that the cleaning treatment tank is provided with a processing liquid tank that allows the processing liquid to fall under its own weight.