JPH03240977A - Liquid chemical treating device - Google Patents

Abstract

PURPOSE:To prevent the excess treatment of a liq. chemical by providing a liq. diluent supply line and a solenoid valve to be closed by the passage of electricity and opened in the event of power failure, supplying a liq. diluent to a liq. chemical treating tank in the event of power failure and stopping the treatment of a material with the liq. chemical. CONSTITUTION:A solenoid valve 10 is closed by the passage of electricity, and the liq. chemical 2 overflowing a reflux liq. chemical treating tank 1 into an outer tank 3 is filtered by a filter 6 and again refluxed to the tank 1. A body is dipped in the tank 1 and treated. Meanwhile, the valve 10 is opened in the event of power failure, a reflux pump 5 is stopped, and the liq. diluent (pure water) is supplied to the tank 1 through a supply line 9. Consequently, the chemical 2 overflows into an outer tank 7 and is discharged through a drainage line 8, the chemical 2 is diluted, and the treatment of the body with the chemical is stopped.

Description

[Detailed description of the invention] The present invention will be described in the following order.

A. Industrial field of application B0 Overview of the invention C1 Prior art 0 Problems to be solved by the invention E1 Means for solving the problems 10 Effects G. Examples [Figures 1 to 3] a. One embodiment [Fig. 1, Fig. 2] b. Other embodiment [Fig. 3] H0 Effect of the invention (A. Industrial application field) The present invention is a chemical processing device, especially a chemical processing tank. The present invention relates to a chemical liquid processing apparatus that performs chemical liquid treatment by immersing an object to be treated in a chemical liquid.

(B. Summary of the Invention) The present invention provides that, in the chemical processing apparatus described above, even if the object to be processed (for example, a semiconductor wafer) is placed in the chemical processing tank for 6 longer than a predetermined time due to a power outage, the chemical processing proceeds excessively. In order to prevent this from happening, a diluent supply route for supplying the diluent to the chemical treatment tank and a valve to open and close it are provided, and in the event of a power outage, the valve is opened to dilute the chemical in the chemical treatment tank with the diluent. This is how it was done.

(C, Prior Art) In the process of manufacturing semiconductor devices, it is necessary to chemically treat semiconductor wafers many times. One example of such chemical treatment is wet etching on the surface of a semiconductor wafer.

Such chemical processing is generally carried out using a chemical processing apparatus in which a semiconductor wafer is immersed overnight in a chemical processing tank in which a chemical solution is stored. There are two types of chemical processing apparatus: a manual type in which semiconductor wafers are immersed in a chemical by hand, and an automatic type in which a transfer robot automatically immerses the semiconductor wafer in the chemical.

(D. Problems to be Solved by the Invention) By the way, no measures against power outages have been taken in conventional chemical treatment tanks.

Therefore, when a power outage occurs, the following problems occur.

If the chemical processing equipment is an automatic type, the transport robot will stop, and if it is a manual type, the indoor lights will be completely turned off and it will be pitch black, making it impossible to continue manual work. It becomes dangerous and manual work has to be interrupted. Therefore, if a power outage occurs during chemical treatment of semiconductor wafers, the conductor wafer remains immersed in the chemical until the power is restored.

As a result, for example, if the chemical treatment is wet etching, the wet etching time becomes longer than the predetermined time, and the surface of the semiconductor wafer is excessively etched, resulting in the problem that all the semiconductor wafers are defective. obtain. That is, although the time for wet etching a semiconductor wafer varies depending on the material, depth, etc. of the film to be etched, it is generally carried out in the range of 30 seconds to 30 minutes, and in most cases the etching time is about 2 minutes. However, it is not known how long the power outage will last, and if the power outage is long, over-etching will inevitably occur, and in the worst case, all semiconductor wafers will be defective. And this results in very large losses.

Furthermore, such problems may also occur during resist peeling, chemical plating, and development. First, in the case of resist stripping, if the semiconductor wafer is immersed in the resist stripping solution for too long, the surface of the semiconductor wafer will be eroded by the resist stripping solution, which is not preferable. Furthermore, if the material is immersed in the chemical plating solution for too long, the plating film thickness will exceed the desired value. In the case of development, a problem arises in that the resist film that should remain after development thins due to excess development time, resulting in a decrease in the accuracy of the phosphor graph.

A possible solution would be to make all chemical processing equipment automatic and also provide a backup power source in case of a power outage. However, the power consumption of the system in which semiconductor wafers are transported between a pure water rinsing device and a chemical processing device using a transport robot is not small, and to back up this power consumption, it is necessary to install a non-negligible in-house power generation device. However, it is actually extremely difficult or impossible to realize this in terms of cost and space.

The present invention has been made to solve these problems, and even if the object to be processed (for example, a semiconductor wafer) is left in the chemical processing tank for longer than a predetermined time due to a power outage, the chemical processing will not proceed excessively. The purpose is to make it possible to achieve this without installing large-scale equipment.

(E. Means for Solving the Problems) In order to solve the above-mentioned problems, the chemical processing apparatus of the present invention is provided with a post-dilution supply path for supplying dilution to the chemical processing tank, and a valve for opening and closing the supply path. The present invention is characterized in that the valve is opened during a power outage to dilute the chemical solution in the chemical solution processing tank by diluting the chemical solution overnight.

(F Effect) According to the chemical processing device of the present invention, when a power outage occurs, the diluting liquid is supplied into the chemical processing tank through the diluting liquid supply path, and the drug is diluted with the diluting liquid.

Therefore, the progress of the drug treatment can be stopped, and it is possible to prevent the drug treatment from being performed excessively.

(G. Embodiment) [FIGS. 1 to 3] Hereinafter, the chemical liquid processing apparatus of the present invention will be described in detail according to the illustrated embodiment.

(a, one embodiment) [Fig. 1, Fig. 2] Fig. 1 (A)
, (B) are configuration diagrams showing one embodiment of the chemical processing apparatus of the present invention, in which (A) shows the state during normal times (during non-power outage), and (B) shows the state during power outage. shows.

In the drawings, l denotes a chemical treatment tank 3 storing a chemical liquid 2 for chemically treating an object (not shown), such as a semiconductor wafer.
is a first outer tank that stores the chemical solution 2 overflowing from the chemical solution processing tank 1, and the height of its upper edge is appropriately higher than that of the chemical solution processing tank 1. 4 is a reflux path for refluxing the chemical liquid 2 from the first outer tank 3 to the chemical liquid processing tank 1; 5 is a reflux pump provided in the reflux path 4; and 6 is a reflux filter; The chemical liquid 2 is returned to the chemical liquid processing tank 1. The reflux system 4.5.6 allows the inside of the chemical liquid processing tank 1 to be always filled with fresh chemical liquid 2 and to use the chemical liquid 2 without wasting it.

The above-mentioned components of the chemical processing device are also present in conventional chemical processing devices, but the components described below are characteristic components of the present chemical processing device.

A second outer tank 7 is provided further outside the first outer tank 3, and stores the chemical solution 2 overflowing from the first outer tank 3. The height of the upper edge of the second outer tank 7 is appropriately higher than that of the first outer tank 3. 8 is a drainage path for discharging the chemical solution stored in the second outer tank 7, 9 is a diluent supply path for diluting the chemical solution into the chemical processing tank, and IO is a normally closed channel provided in the supply path 9. It is a solenoid valve. Therefore, in normal times,
That is, during non-power outage, the solenoid valve 10 remains closed,
The diluent is not supplied into the chemical treatment tank l through the diluent supply path 9.

However, when a power outage occurs and as a result, the electromagnetic valve 10 is no longer energized, the electromagnetic valve 10 enters the oven state, and as a result, the diluted liquid flows from the diluted liquid storage tank (not shown) into the chemical processing tank 1 through the diluted liquid supply path 9. will be supplied.

In this chemical processing apparatus, as shown in FIG. 1(A), normally the solenoid valve 10 is closed and the reflux system chemical processing tank l
A reflux state continues in which the chemical solution 2 overflowing into the first outer tank 3 is filtered by the filter 6 and returned to the chemical solution processing tank 1 as a fresh chemical solution.

By immersing the semiconductor wafer in the chemical treatment tank 1 in this state for a predetermined period of time, a chemical treatment, for example, etching, is performed. For example, 5i formed on the surface of a semiconductor substrate
When etching the n2 film, the chemical solution 2 is an aqueous solution of hydrofluoric acid HF. Note that the diluent for this is pure water.

By the way, if a power outage occurs during operation of the chemical processing equipment, the solenoid valve 10 opens as shown in Fig. 1 (B).
The reflux pump 5 stops together with the oven). Therefore,
When the reflux of the chemical solution 2 is stopped and the electromagnetic valve 10 is opened, a diluted solution, for example, pure water, is supplied to the chemical solution processing tank 1 through the diluted solution supply path 9.

By supplying this diluent, the chemical solution 2 is diluted and the liquid level of the chemical solution 2 in the chemical solution processing tank l becomes high. be discharged. If this state continues, the concentration of the chemical solution 2 in the chemical solution treatment tank 1 decreases at a rate corresponding to the amount of diluted solution supplied per unit time, and the concentration eventually becomes negligible or zero. In other words, the chemical agent 2 in the chemical treatment tank l
This means that the diluent has replaced the diluent.

Therefore, the progress of the chemical treatment such as etching will be stopped soon after the power outage, and there is no possibility that the chemical treatment will become excessive even if the power outage is long. Therefore, it is possible to prevent all of the semiconductor wafers in the chemical treatment tank 1 from being defective and causing a large loss.

Figures 2 (A) and (B) show modified examples of the chemical processing equipment shown in Figure 1. Figure 2 (A) shows the state during normal (non-power outage), and ) indicates the status at the time of power outage.

This chemical processing device does not have a second outer tank in the chemical processing tank l (
It differs from the chemical processing device shown in Fig. 1 in that the first outer tank 3 is provided) and the chemical processing tank l is placed inside the sink 7a, but other than that, it is exactly the same. I won't give any particular explanation.

(b, Other Embodiments) [Fig. 3] Fig. 3 (A) and (B) are configuration diagrams showing other embodiments of the chemical liquid processing apparatus of the present invention, and (A) is a normal (non-normal) (B) shows the state in which it revs during a power outage.

This chemical liquid processing equipment has a power failure detection means and a valve control circuit that controls a solenoid valve according to the output of the power failure detection means.The valve control circuit etc. is powered by a battery different from the commercial 1 source. It's supposed to work.

Since the parts common to the chemical liquid processing apparatus shown in FIG. 1 of this embodiment have already been explained, the same reference numerals used in FIG. Only those parts will be explained in detail.

Reference numeral 11 denotes an electric wire 12 that supplies commercial power current to the chemical processing device.
A power outage sensor detects the presence or absence of a power outage by, for example, electromagnetically detecting whether or not current is flowing through the power outage sensor, and 13 is a valve that receives an output signal from the power outage sensor 12 and controls the solenoid valve 10 and a solenoid valve 15 to be described later. It is a control circuit.

Reference numeral 14 denotes a chemical liquid extraction path for removing the chemical liquid 2 from the chemical liquid processing tank 1; 15, a solenoid valve provided in the chemical liquid extraction path 14;
Reference numeral 6 denotes a chemical liquid reservoir for storing the chemical liquid 2 extracted through the chemical liquid draining path 14. The purpose of having this chemical solution extraction system 14, 15, and 16 is to first drain the chemical solution in the chemical solution processing tank 1 in the event of a power outage, and then supply the diluted solution into the chemical solution processing tank 1 to dilute the chemical solution more quickly. It's for a reason.

A battery 17 is a power source for driving the power outage sensor 11 and the valve control circuit 13. Since it must operate even during a power outage, it requires a commercial power source and a battery as a separate power source.

Next, the operation of this chemical liquid processing apparatus will be explained.

In the normal state shown in FIG. 3(A), both electromagnetic valves 9 and 15 are held in a closed state.

Chemical treatment tank 1 in this case. Chemical liquid reflux system 4.5.6
The state is the same as that shown in FIG. 1(A).

By the way, when a power outage occurs, the power outage sensor 11 detects the power outage. Then, the valve control circuit 13 starts measuring time using a built-in timer (not shown). Then, when the power is not restored even after a predetermined period of time, for example, one minute has passed, the solenoid valve 15 is first opened. Then, the chemical liquid 2 in the chemical liquid processing tank 1 is drained into the chemical liquid reservoir 16 through the chemical liquid drain path 14.

Next, the electromagnetic valve 15 is closed, and then the electromagnetic valve 10 is opened so that the diluent is supplied into the chemical treatment tank 1 from the diluent storage tank (not shown) through the diluent supply path 9.

As a result, the inside of the chemical treatment tank 1 is filled with the diluent, and the diluted liquid further overflows from the chemical treatment tank 1 and is discharged through the drain path 8. Through this operation, the inside of the chemical treatment tank 1 is cleaned with the diluent.

Then, when a predetermined period of time (set to a time sufficient to clean the inside of the chemical processing tank 1) has elapsed after starting supply of the diluted liquid into the chemical processing tank 1, the solenoid valve 10 is switched to the closed state. .

According to this chemical liquid processing device, first of all, even if a power outage starts, control of the solenoid valve 15.10 is not started immediately, so that it can be used to respond to a short power outage that does not interfere with chemical liquid processing. You can get away with not having to do any action.

In other words, when the chemical processing time is set to 30 minutes, for example, the chemical processing time may change from 1 to 30 minutes due to a power outage.
Normally, there is no problem after 2 minutes longer. However, according to the chemical liquid processing apparatus shown in FIGS. 1 and 2, once a power outage occurs, the chemical liquid in the chemical liquid processing tank l is diluted with a diluent. If such an operation is performed once, even if the power is restored, it will be a hassle to remove the semiconductor wafer from the chemical processing tank 1, add a new chemical into the chemical processing tank 1, reinsert the semiconductor wafer, and perform the chemical processing again. Will the work require diluted drugs? Since a is drained, a large amount of waste occurs.

Therefore, if the power outage lasts for a short time so that it does not pose a problem for chemical processing, it is preferable not to take action in response to the power outage. According to this chemical liquid processing device, when a power outage starts, it starts measuring time, and when the power outage continues even after a preset period of time has elapsed, the solenoid valve is controlled. It is possible to prevent operations in response to a power outage from taking place.
This allows you to avoid large amounts of unnecessary waste.

Second, when it is necessary to dilute the chemical solution in response to a power outage, first open the solenoid valve 15 and dilute the chemical solution.
Since the diluent is supplied by opening the electromagnetic valve lO which has been pulled out, it is possible to eliminate wastage of the chemical solution and to reduce the amount of diluent required for diluting the chemical solution 2.

That is, in the case of the chemical liquid processing apparatus shown in FIGS. 1 and 2, when a power outage occurs, the chemical liquid 2 in the chemical liquid processing tank 1 is diluted by the diluting liquid and becomes waste, and is wasted. Furthermore, the amount of diluting solution required to sufficiently dilute the concentration of the chemical solution becomes extremely large. Although the concentration of the chemical solution in the waste liquid gradually decreases, it is initially high, which increases the processing time required to render it harmless so that it can be disposed of, and the amount of chemicals required for the processing. However, according to this chemical solution processing device,
At the time of power outage, the chemical liquid 2 in the chemical liquid processing tank 1 is temporarily transferred into the chemical liquid 16, so that the chemical liquid 2 can be used later, and the waste of the chemical liquid 2 can be eliminated. Further, the consumption of chemicals required for detoxifying the product so that it can be disposed of is also small.

Furthermore, since the diluent is supplied after the chemical 2 is removed from the chemical treatment tank 1, the amount of diluted liquid required to clean the inside of the chemical treatment tank 1 can be significantly reduced. In this respect, it is also economical, and the concentration of the waste liquid is low, making it easy to treat.

Thirdly, the electromagnetic valve 10 is closed and the supply of the diluent is stopped after a certain period of time has elapsed after the start of the supply of the diluent.
It is possible to prevent the diluent from being wasted.

That is, once the inside of the chemical treatment tank 1 becomes clean to a certain extent, it is no longer necessary to supply the diluent. Therefore, the diluent is automatically stopped after a certain period of time has elapsed after the diluent was started to be supplied. Even if the diluting liquid is water, it must be subjected to deionization treatment, and it is by no means cheap and it is not preferable to waste it, but this chemical solution treatment device can eliminate such waste.

Note that the battery 17 is connected to the power outage sensor 2 and the valve control circuit 13.
Since it is sufficient to supply the power necessary for the operation of the solenoid valve 9.15 and the opening/closing of the solenoid valve 9.15, the power may be small. Also, it only needs to have a lifespan longer than the time normally expected for a power outage.

A lifespan of 100 or 200 hours is not required. Therefore, a large battery is not required.

The present invention is applicable not only to wet etching apparatuses but also to chemical processing apparatuses in general, such as chemical plating apparatuses, developing apparatuses, and resist film stripping apparatuses.

Incidentally, when the present invention is applied to a developing device, when the developer is aqueous, the diluent is pure water, and when the developer is organic solvent, the organic solvent is the diluent. Furthermore, in the case of resist stripping, an organic acid is generally used as a chemical solution, but the diluent for it is pure water.

(H, Effect of the invention) As stated above, the chemical liquid processing apparatus of claim (1):
The present invention is characterized by having a diluent supply path for supplying a diluted liquid to the chemical treatment tank, and a solenoid valve that closes when the diluent supply path is energized and opens when it is not energized.

Therefore, according to the chemical processing apparatus of claim (1), when a power outage occurs, the diluting liquid is supplied into the chemical processing tank through the diluting liquid supply path, and the chemical liquid is diluted by the diluting liquid. Therefore, the progress of the chemical liquid treatment can be stopped, and in turn, excessive chemical liquid treatment can be prevented.

The chemical processing apparatus according to claim (2) includes: a diluent supply path for supplying the diluted liquid in the chemical processing tank; a valve for opening and closing the diluent supply path; a power outage detection means for detecting the presence or absence of a power outage; The present invention is characterized by comprising a valve control circuit that receives an output signal from the detection means and controls the electromagnetic valve.

Therefore, according to the chemical processing device of claim (2), the valve control circuit appropriately controls the solenoid valve according to the detection result of the presence or absence of a power outage by the power outage detection means, so that, for example, a short power outage is ignored. It becomes possible to respond to power outages in a variety of ways, such as by limiting the supply time of diluent.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) are configuration diagrams showing one embodiment of the chemical liquid processing apparatus of the present invention. FIG. 1(A) shows the state during normal (non-power outage), and FIG. FIGS. 2(A) and 2(B) are configuration diagrams showing a modified example of the chemical liquid processing apparatus shown in FIG.
FIG. 3(B) shows the state during power outage (without power outage), and FIG. 3(A) and FIG. Diagram (A)
(B) shows the state during normal (non-power outage) times, and (B) shows the state during power outages. Explanation of symbols 1... Chemical solution processing tank, 2... Chemical solution, 9... Diluent supply path, 10... Solenoid valve, 11... Power outage detection means, 13... Valve control circuit. 0- (A) I is force, σ) Implementation Ishi figure 3 CB)

Claims (2)

[Claims] (1) In a chemical treatment device that performs chemical treatment by immersing an object in a chemical treatment tank, a diluent supply path that supplies diluted liquid to the chemical treatment tank; and energization of the diluted liquid supply path. A chemical liquid processing device comprising: a solenoid valve that closes when the power is turned off and opens when the power is not energized; (2) In a chemical treatment device that performs chemical treatment by immersing the object to be treated in a chemical solution in a chemical treatment tank, a diluent supply path that supplies diluted liquid to the chemical treatment tank; and opening/closing of the diluted liquid supply path. A chemical liquid processing device comprising: a valve that detects a power outage; a power outage detection device that detects the presence or absence of a power outage; and a valve control circuit that receives an output signal from the power outage detection device and controls the solenoid valve.