JPH0736399B2 - Cleaning rinse tank for semiconductor wafers - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning rinse tank for semiconductor wafers used when cleaning wafers with pure water.

[0002]

2. Description of the Related Art In semiconductor manufacturing, dust contained in air,
In addition to impurities such as impurities brought in by workers and various equipment from adhering to the wafer, deposits such as raw materials used in the etching process, and even cleaning with a chemical solution cause the chemical solution itself to adhere, so that they can be removed. The step of washing with running pure water is essential. Usually, for example, a chemical bath containing a chemical such as a high temperature mixture of sulfuric acid and hydrogen peroxide and a cleaning rinse bath for flushing with the supplied pure water are prepared, and the wafer is transferred from the chemical bath to the cleaning rinse bath. And sequentially move to wash. Strictly speaking, pure water has the ability to dissolve all substances, albeit in trace amounts, and running water cleaning using this not only replaces and removes the chemicals used in chemical cleaning, but also uses pure water itself as the final finishing cleaning. It is also a precision cleaning process that expects the ability. As a basic structure of a conventional cleaning rinse tank, as shown in FIGS. 4 and 5, a supply pipe b having a discharge port toward the wafer c is arranged at the bottom or the inner wall of the tank a, and a single supply pipe b is provided. Alternatively, in many cases, pure water is discharged from a plurality of discharge ports to wash the wafer c with running water and overflow excess water from the upper part of the tank a.

[0003]

In the conventional structure, the pure water discharged from the discharge port of the supply pipe b is the wafer c.
Although it flows to the upper part after flowing in the direction of, the flow mainly follows the side wall near the upper part of the tank a, and excess water overflows from the upper end of the side wall. Therefore, in the central part of the water surface of the tank a, the stagnation is hardly generated due to the influence of the flow, and the impurities floating in the stagnation are gathered, so that the stagnation cannot be escaped forever.
However, the loading / unloading of the wafer c into / from the bath a is performed through such a stagnation portion. The impurities gathered in the stagnation may be attached when the wafer c is taken out, and may be attached again when the cleaned wafer c is taken out from the bath, thus contaminating the wafer.

Further, the pure water supplied flows upward from the lower part of the tank a, but such a flow does not necessarily make the water quality in the tank uniform, and especially stays at the corner near the bottom of the tank a. The area e is generated, the water quality of the pure water in the tank itself is deteriorated, the replacement characteristic of the wafer for contaminants is impaired, and not only cleaning takes a long time, but also the cleaning quality as designed cannot be maintained. In order to maintain good displacement characteristics or cleaning ability of pure water, it may be possible to devise the arrangement and shape of the discharge port to create a flow that stirs the inside of the tank thoroughly. However, in such a method, air is dissolved in pure water to increase the concentration of dissolved oxygen in pure water, which causes a problem such as formation of a natural oxide film. In addition, it is difficult to create a flow that stirs the inside of the tank thoroughly, and it is not effective to form a stagnant portion in the tank or to wind up impurities accumulated at the bottom.

The present invention solves the problems of the prior art as described above, makes it possible to efficiently maintain the replacement characteristic of pure water or the cleaning ability by eliminating the occurrence of stagnation and stagnant flow regions, and improve the cleaning quality. An object is to provide a cleaning rinse tank for semiconductor wafers.

[0006]

In order to achieve the above object, the present invention provides a process of cleaning and rinsing a semiconductor wafer with pure water.
In the cleaning rinse tank for semiconductor wafers used in
It is installed on one side of the upper part of the tank, and it discharges pure water horizontally.
It is provided on the other side of the water supply part and the upper part of the tank to supply the pure water.
A part of the pure water supplied from the supply part is used as the surface water flow.
-Overflow frame part drained by flow and pure water inside the tank
The drainage port that guides the
The gist of the present invention is to have a drainage amount control unit for controlling the amount of drainage drained .

[0007]

According to the above construction, the deionized water supply unit forms an overflow surface water flow in one direction on the tank water surface, and this surface water flow pushes away the stagnation that tends to occur on the tank water surface as in the conventional case, and Structurally prevent the occurrence. In addition, the deionized water in the tank is guided downward in the course of drainage by the drainage port at the lower portion of the tank to drain the pure water, and the downward flow of the drainage structurally prevents the generation of a retention area inside the tank.

[0008]

1 and 2 show a first embodiment of the present invention. The semiconductor wafer cleaning rinsing tank 1 shown in FIG. 1 is provided with an overflow frame portion 3 which is integrally provided on the upper portion of the tank 2 and a pure water supply portion which is provided on one side of the tank 1 and horizontally discharges pure water. 4 and
The tank is provided with a punching plate 5 installed on the lower side of the tank and a drainage port 6 provided on the bottom of the tank.

The overflow frame portion 3 is formed by an inclined wall 2b having an intermediate portion located between both side walls 3a and inclined obliquely upward, and overflows excess water in the tank through the tip of the inclined wall 2b. The pure water supply unit 4 has a discharge pipe 7 installed along the upper side of one side of the tank 1, and an introduction pipe 8 connected to an intermediate portion of the discharge pipe 7 in a T-shape. The discharge pipe 7 has a plurality of discharge ports (not shown) provided on the side facing the inclined wall 2b, and these discharge ports are installed at a height substantially horizontal to the tip of the inclined wall 2b. The introduction pipe 8 is connected to a pure water supply facility. The pure water supply amount can be appropriately adjusted by the needle valve 9 of the supply water amount control unit 10, and the pure water of the pure water tank 11 which is a storage tank is discharged from the discharge port of the discharge pipe 7 at a predetermined flow rate. .

The punching plate 5 has a plurality of pores 5a penetrating in the vertical direction and is horizontally held near the bottom of the tank on the side wall. A drain port 6 is provided at the bottom of the tank located below the punching plate 5. An end portion of the drain pipe portion 13 extending from the drain port 6 is connected to a water flow pump or a needle valve 15 capable of adjusting a suction water amount by a drainage amount control unit 14.

Next, the above-mentioned cleaning and rinsing tank will be described in more detail together with its function and effect. When cleaning the wafer c, the needle valve 9 is adjusted to pump pure water from the overflow frame 3 until it overflows. Supply water amount control unit 10
The supplied pure water overflows a part thereof and is partly discharged together with the pure water in the tank through the pores 5a of the punching plate 5 and drained from the drainage port 6 To do so. That is, in this embodiment, the discharge pipe 7
Since the amount of water supplied from the discharge port and the amount of water discharged from the drainage port 6 can be adjusted by the supply water amount control unit 10 and the drainage amount control unit 14, a water flow in two directions indicated by arrows is formed in the tank. Then, the wafer c is cleaned in this state.

The water flow from the discharge pipe 7 to the inclined wall 2b is
A one-way overflow surface water flow is formed on the water surface of the tank to push away the stagnation that tends to occur on the water surface of the tank as in the past. In this case, since the inclined wall 2b has a gentle slope, a uniform flow is created on the water surface without generating a vortex in the tank. In addition, such a surface water flow acts as a lid of the cleaning rinse tank, and impurities such as dust are mixed from the outside into the lower water area of the surface water flow in the cleaning rinse tank, and it is possible for the air and the air to melt. The generation of a natural oxide film on the wafer c due to this is also prevented. Since the water flow toward the drainage port 6 is resistant to the water flow of the punching plate 5, the amount of water passing through the pores 5a of the punching plate 5 becomes uniform in each part and creates a uniform downward flow in the tank. Therefore, there is no generation of a stagnant portion in the tank as in the conventional case, and the impurities accumulated in the tank are also quickly discharged through the punching plate 5 and the drainage port 6, so that the pure water in the tank has its replacement characteristic or Efficiently maintain cleaning ability. In addition, although the tank 2, the overflow frame portion 3, and the punching plate 5 are made of quartz and the respective parts are integrally formed in the embodiment, the material and the molding of the respective parts are not limited to this, and similar accuracy is obtained. As long as the above can be obtained.

FIG. 3 shows a second embodiment of the present invention.
The same reference numerals are used for technically the same parts as those of the cleaning rinse tank, and the description thereof is omitted, and different technical configurations are described in detail. The cleaning rinse tank 1 of the same drawing is different from the running water cleaning method of the above-described embodiment in that the second pure water supply units 21, 22, 23, 24 are additionally provided in the tank. These pure water supply parts are cylindrical pipes that are piped on the inner wall of the tank. A plurality of pores are opened in each cylindrical tube toward the center of the tank, and pure water is showered from each pore toward the wafer c. It was designed to be exhaled. In the overflow frame portion 30, the inclined wall 12b is formed in the same manner as in the above-described embodiment, and the backflow prevention plate 2 is formed on the base side of the inclined wall 12b and rises in the diagonally upper direction opposite to the inclined wall 12b.
Has 0.

In the cleaning rinse tank 1 described above, the following points are added to the operational effects of the first embodiment. First, since pure water is discharged from the pure water supply units 21, 22, 23, and 24 toward the wafer c in a shower shape, a stirring flow is generated in the tank, and the wafer c can be washed more quickly and efficiently. Moreover, the punching plate 5 and the drainage port 6 allow the water to be uniformly drained in a state where no stagnant portion is generated in the tank. Pure water supply unit 2
By adjusting the amount of pure water discharged from 1, 22, 23, 24, the amount of water discharged from the drain port 6, and the amount of pure water discharged from the pure water supply unit 4, the pure water supplied from the pure water supply unit 4 is adjusted. It is also possible to use the water exclusively as an overflow water flow that pushes the stagnation, and such an overflow water flow acts as a lid of the cleaning rinse tank as described above. In addition, the backflow prevention plate 20 includes the inclined wall 12b.
However, the reverse flow of the overflow liquid pushed from one side to the other side by the pure water discharged from the pure water supply unit 4 is reliably prevented, and the reliability is improved.
Thus, the cleaning rinse tank of the present invention can be variously modified or developed within the scope of the claims.

[0015]

As described above, in the cleaning rinse tank of the present invention, since the unidirectional overflow surface water flow can be formed on the tank water surface by the deionized water supply unit, the stagnation on the tank water surface as in the conventional case can be prevented. Further, since the surface water flow serves as a tank lid, it is possible to prevent dust from being mixed in from the outside and increase in the dissolved oxygen concentration of the pure water in the tank due to contact with air. Further, since a uniform water flow downward can be formed by the drainage port, a retention flow area is not generated in the tank. Therefore, according to the present invention, the problems of the conventional structure can be eliminated by a relatively simple structure, the generation of stagnation and retention basin can be eliminated, and the displacement characteristics or cleaning capacity of pure water can be efficiently maintained, and the quality of pure water cleaning can be improved. And reliability can be improved.

[Brief description of drawings]

FIG. 1 is a side sectional view of a semiconductor wafer cleaning rinse tank shown as a first embodiment of the present invention.

FIG. 2 is a plan view of the cleaning rinse tank as viewed from above.

FIG. 3 is a side sectional view of a semiconductor wafer cleaning rinse tank shown as a second embodiment of the present invention.

FIG. 4 is a side sectional view of a semiconductor wafer cleaning rinse tank shown as a conventional example.

FIG. 5 is a side cross-sectional view of a semiconductor wafer cleaning rinse tank shown as another conventional example.

[Explanation of symbols]

 1 Rinse cleaning tank 2 Tank 3,30 Overflow frame part 4 Pure water supply part 5 Punching plate 6 Drain port 7 Discharge pipe 13 Drain pipe part c Wafer

Claims (1)

[Claims] 1. A cleaning rinsing tank for a semiconductor wafer to be used in the step of cleaning rinsing the semiconductor wafer with pure water, and pure water supply unit for discharging the pure water provided on one side of the tank top in the horizontal direction, the The blunt water provided on the other side of the tank
A part of the pure water supplied from the supply unit is used as a surface water stream.
And overflow frame portion for draining the bars flow, a water outlet for draining leading the pure water inside the tank to the lower direction, from the exhaust Minakuchi
A cleaning rinsing tank for semiconductor wafers, comprising: a drainage control unit for controlling the amount of drainage .