JP3077140B2 - Semiconductor device manufacturing equipment - Google Patents

Description

The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly to an apparatus for cleaning an etching solution in a liquid storage tank of a wet etching apparatus.

[Prior Art] Conventionally, as shown in FIG. 3, this type of wet etching apparatus draws out a piping system from a bottom portion of a liquid storage tank 1 for storing an etching solution 2 and supplies an electromagnetic valve 4a to the piping system. , A pump 5, a filter 6, and a solenoid valve 4f.
It had a structure to return to. Reference numeral 8 denotes a liquid replenishment line, 4d denotes an electromagnetic valve provided in the line 8, 7 denotes a processing tank liquid supply line, and 4e denotes an electromagnetic valve provided in the line 7.

[Problems to be solved by the invention]

In the above-described conventional wet etching apparatus, the etching solution is extracted and filtered only at one location of the liquid storage tank 1, but the etching liquid in the tank apart from the sampling portion is hardly filtered. Has the drawback that it is not possible to completely filter and clean all the etchants. In addition, since the fine particles cannot be completely removed by only one filtering of the etching solution, it is necessary to clean the etching solution by filtering a number of times, and the cleaning of the etching solution in the storage tank takes more than half a day. There is a disadvantage that filtering must be performed.

An object of the present invention is to provide a semiconductor device manufacturing apparatus which solves the above-mentioned problems.

[Differences of the Invention from the Prior Art]

In contrast to the conventional wet etching apparatus described above, the present invention agitates the etching solution in the storage tank,
There is a difference in that it is possible to prevent a locally contaminated etchant from accumulating, and to extract and filter the etchant at a plurality of locations to clean the etchant in the storage tank in a short time.

[Means for solving the problem]

In order to achieve the above object, a method for manufacturing a semiconductor device according to the present invention includes a stirrer for stirring an etchant in a liquid storage tank, and etching from a plurality of locations in the liquid storage tank while stirring the etchant with the stirrer. It has a mechanism for sequentially extracting the liquid, filtering the etching liquid and then returning it back to the liquid storage tank, and a mechanism for feeding the etching liquid in the liquid storage tank after the predetermined filtering to the etching processing tank. Things.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

In the figure, pipes are respectively led out from three places at the bottom of the liquid storage tank 1, and each pipe is provided with a solenoid valve 4a, 4b, 4c and connected to a pump 5 and a filter 6, and the discharge side of the filter 6 is connected to a solenoid valve. It is returned to the storage tank 1 via 4f. 8 is a liquid replenishing line, 4d is its solenoid valve, 7 is a processing tank liquid supply line, and 4e is its solenoid valve.

On the other hand, at the bottom of the liquid storage tank 1, stirrs 3, 3 for stirring the etching liquid are installed. The etching solution 2 is filled in the liquid storage tank 1. The stirrer 3 constantly operates to stir the etching liquid 2 in the liquid storage tank 1. The etching solution 2 is replenished from the solution replenishing line 8 and filtered by the filter 6 and then supplied to the storage tank 1. At the time of liquid supply, the operation is performed with the solenoid valves 4a, 4b, 4c, and 4e closed and the solenoid valves 4d and 4f opened. After the filtering is sufficiently performed and the etching solution 2 is cleaned, the solenoid valves 4a.4b.4
d. By closing 4f and opening the solenoid valves 4c and 4e, the etching liquid 2 is supplied from the processing tank liquid supply line 7 to the etching processing tank. The solenoid valves 4d and 4e are closed except when replenishing the supply liquid. First, filtering is performed for 10 minutes with the solenoid valves 4c and 4f opened and the solenoid valves 4a and 4b closed. Next, filtering is performed for 10 minutes with the solenoid valves 4b and 4f opened and the solenoid valves 4a and 4c closed. Next, filtering is performed for 10 minutes with the solenoid valves 4a and 4f opened and the solenoid valves 4b and 4c closed. Then again the solenoid valve
4c, 4f are opened and the solenoid valves 4a, 4b are closed, and so on. This makes it possible to completely and efficiently filter the etching liquid 2 in the liquid storage tank.

Embodiment 2 FIG. 2 is a configuration diagram showing Embodiment 2 of the present invention.

In the present embodiment, a liquid fine particle measuring device 9 is connected to the subsequent stage of the pump 5 to count particles in the etching solution 2 sent from the pump 5 in real time, and the electromagnetic valve controller 10 controls the electromagnetic valve according to the number of particles. The opening and closing of each of 4a, 4b, and 4c is controlled. First, the filtering with the solenoid valves 4c and 4f opened and the solenoid valves 4a and 4b closed is performed until the particle count becomes equal to or smaller than the standard value α. Next, open the solenoid valves 4b and 4f,
Filtering is performed with the solenoid valves 4a and 4c closed until the particle count becomes equal to or smaller than the standard value α. Next, while the solenoid valves 4a and 4f are opened and the solenoid valves 4b and 4c are closed, filtering is performed until the particle count becomes equal to or smaller than the standard value α. If the opening time of the solenoid valve 4a is 3 minutes or more, the above three states are repeated many times. When the time during which the solenoid valve 4a is open becomes less than three minutes, the solenoid valve controller 10 switches so as to repeat the above three states until the standard value β (β <α) is satisfied. However, if each of the three states lasts for 30 minutes or more, the state transitions to the next state without reaching the standard values α and β. Standard values α and β are 1 to 50
The number of particles is 0 / ml, and those having a particle size of 0.2 μm or more are counted. In this embodiment, since the filtering time of each part in the liquid storage tank 1 is determined by the degree of contamination of the liquid, the filtering is shifted to the next place when the filtering is sufficiently performed, and the most effective method is performed. There is an advantage that filtering can be performed in time.

FIG. 4 is a graph showing a change in the number of particles in the etching solution due to filtering of the liquid storage tank according to the second embodiment of the present invention and a conventional liquid storage tank. While it takes 10 hours for the number of particles in the conventional liquid storage tank to become 10 particles / ml or less, the number of particles in the liquid storage tank of the second embodiment of the present invention becomes 10 particles / ml or less. It took only 6 hours, and it was found that the time required for filtering could be reduced.

〔The invention's effect〕

As described above, the present invention stirs the etching liquid in the liquid storage tank by installing the stirrer in the liquid storage tank of the wet etching apparatus, and allows the local etching liquid 2 to be stirred.
It has the effect of preventing stagnation. Further, since the etching solution is extracted at a plurality of locations and filtering is performed, there is an effect that the etching solution in the storage tank can be efficiently and completely cleaned. Since the etchant can be cleaned in a short time, stable operation of the wet etching apparatus can be realized, and there is an effect that a stable semiconductor element can be manufactured.

[Brief description of the drawings]

1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment, FIG. 3 is a block diagram showing a conventional liquid storage tank, and FIG. 4 is an embodiment of the present invention. FIG. 2 is a diagram showing a change in the number of particles in an etching solution due to filtering of a liquid storage tank of No. 2 and a conventional liquid storage tank. DESCRIPTION OF SYMBOLS 1 ... Storage tank, 2 ... Etching liquid 3 ... Stirrer 4a, 4b, 4c, 4d, 4e, 4f ... Solenoid valve 5 ... Pump, 6 ... Filter 7 ... Processing tank liquid supply line, 8 …… Replenishment line 9 …… Liquid particle measuring instrument 10 …… Solenoid valve controller

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/306 H01L 21/3063 H01L 21/308

Claims (1)

(57) [Claims] 1. A stirrer for stirring an etching solution in a storage tank, and sequentially extracting the etching solution from a plurality of locations in the storage tank while stirring the etching solution with the stirrer, and filtering the etching solution. An apparatus for manufacturing a semiconductor device, comprising: a mechanism for returning to the inside of a liquid storage tank again; and a mechanism for feeding an etching solution in the liquid storage tank after the predetermined filtering to the etching processing tank.