JPH0557033B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a solvent cleaning tank that is most suitable for use in cleaning impurities from objects to be cleaned, such as silicon wafers.

Prior Art For example, silicon wafers and the like generally need to be cleaned with a solvent after mirror polishing to remove impurities such as organic matter and dust adhering to the surface.

Conventionally, when cleaning wafers with a solvent, the wafers are cleaned in batches for a certain amount of time or a certain number of times, and then the entire amount of the solvent contaminated with impurities in the cleaning tank is replaced with fresh solution.

In such conventional solvent cleaning tanks, soluble and insoluble impurities accumulate in the solvent, so if the solvent is not replaced frequently, the desired cleaning effect cannot be maintained, resulting in deterioration of wafer quality after cleaning and Value analysis due to the large amount of solvent used
I had the above problem.

In addition, Utility Model Application Publication No. 53-150063 discloses that in a solvent cleaning device for cleaning objects to be cleaned with a solvent, multiple stages of solvent cleaning tanks are arranged, and the solvent supplied to the upper solvent cleaning tank overflows to the bottom. This figure shows a multi-stage cleaning tank including a group of solvent cleaning tanks that sequentially fill the main accommodating part of the lower solvent cleaning tank through a part surrounded by a partition plate with an inlet opening.

In addition, Utility Model Application No. 59-166887 discloses that a water storage tank is provided, and the washing water supplied to the main storage part of the washing tank overflows in all directions, and the overflowing solvent is temporarily stored at the bottom of the water tank. This shows a cleaning device equipped with a filter that circulates cleaning water at the bottom of the cleaning tank and filters out impurities.

Problems to be Solved by the Invention In such conventional cleaning devices, impurities floating near the surface of the cleaning liquid cannot be flowed out without passing through the main storage section that accommodates the objects to be cleaned. However, there is a drawback that floating impurities contaminate the object to be cleaned before being discharged.

This invention was made to solve these problems, and in particular, it is possible to clean the object to be cleaned while maintaining a high level of cleaning effect without contaminating the object with impurities, and to reduce the amount of solvent used. The purpose of the present invention is to provide a solvent cleaning tank that can significantly reduce the amount of waste.

Means for Solving the Problems Therefore, in order to achieve this object, the present invention provides a solvent cleaning device for cleaning an object to be cleaned with a solvent, in which a plurality of solvent cleaning tanks are arranged, and a subsequent solvent is removed. The solvent supplied to the main storage part of the cleaning tank overflows in all directions, passes through the auxiliary storage part, and is sequentially supplied from the bottom of the main storage part of the previous solvent cleaning tank, filling the main storage part of the previous solvent cleaning tank. a group of solvent cleaning tanks, and a circulation filtration mechanism that circulates solvent from the bottom of each of the auxiliary storage parts that temporarily stores overflowing solvent to the bottom of the main storage part of each corresponding solvent cleaning tank to filter impurities. and an introduction part that introduces fluid into the bottom of the main storage part on the front stage side, and there is a difference in wall height between the introduction part and the main storage part on the front stage side. The gist of the present invention is a solvent cleaning device characterized in that an auxiliary storage section is provided to accommodate the solvent overflowing from both the introduction section and the introduction section.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

Embodiment 1 FIGS. 1 and 2 show a preferred embodiment 1 of the solvent cleaning apparatus of the present invention. Inside the outer tank 1 is a solvent cleaning tank group G consisting of a plurality of solvent cleaning tanks 2, 3, and 4.
is arranged. In this embodiment, the solvent cleaning tank group G has front, middle, and rear solvent cleaning tanks, but it may be more or less than that.

The solvent cleaning tanks 2, 3, and 4 to which the solvent 5 is supplied are as follows:
They are sequentially arranged along the forward direction of cleaning of the wafer W, which is the object to be cleaned (the order of immersion in the solvent, indicated by arrow A in FIG. 1).

The foremost solvent cleaning tank 2 has tank walls 6 surrounding it on all sides.
and partition walls 7, 8, and 9.

Main storage part 10 and partition wall 9 surrounded by tank wall 6
The introduction part 11 surrounded by the outer tank 1 and the outer tank 1 are connected through an opening 12 on the bottom side.

As shown in FIG. 1, the upper end of the partition wall 9 is higher than the upper end of the partition wall 8 by a predetermined height h1, and the upper end of the tank wall 6 is lower than the upper end of the partition wall 8 by a predetermined height h2. . In addition, the upper end of the partition wall 7 is connected to the tank wall 6
It is lower than the upper end by a predetermined height h3. The predetermined heights h1, h2, h3 are actually about 5 mm, for example.

The main storage portion 10 surrounded by the tank wall 6 is provided with a solvent inlet 13 and a solvent outlet 14 at the bottom of the tank. This solvent discharge port 14 is for returning the solvent 5 contaminated by cleaning the wafers W in the main storage section 10 to the solvent regeneration device 15 or for discharging it to the waste liquid treatment tank 16.

This solvent regenerating device 15 has a function of removing soluble impurities contained in the used solvent 5 by, for example, distillation, and making the solvent 5 a new regenerated liquid.

The auxiliary storage part 17 surrounded by the tank wall 6, the partition walls 7 and 8, and the outer tank 1 has a solvent outlet 18 and a solvent outlet 18 at the bottom of the tank.
18 are provided. The solvent outlets 18, 18 are
It is connected to the solvent inlet 13 via a circulation filtration mechanism 19 . This circulation filtration mechanism 19 includes a pump 20
a and a filter 20b.

Further, a discharge section 2 surrounded by a partition wall 7 and an outer tank 1 is provided.
1 is provided with a discharge port 22 at the bottom of the tank.
This discharge port 22 is connected to the solvent regeneration device 15.

Next, the middle stage solvent cleaning tank 3 has a tank wall 23 surrounding it on all sides and partition walls 24 and 25.

The main storage part 26 and the partition walls 24 and 25 surrounded by the tank wall 23 and the introduction part 27 surrounded by the outer tank 1 are connected through an opening 28 on the bottom side.

As shown in FIG. 1, the upper end of the partition wall 25 is higher than the upper end of the partition wall 24 by a predetermined height h4, and the upper end of the tank wall 23 is higher than the upper end of the partition wall 24 by a predetermined height h5.
It's getting lower. Moreover, the upper end of the tank wall 23 is
It is higher than the upper end of the partition wall 9 by a predetermined height h6. The predetermined heights h4, h5, and h6 are set to, for example, 5 mm.

The main storage section 26 has a solvent inlet 29 at the bottom of the tank.
and a solvent outlet 30 are provided. This solvent inlet 29 is used to remove the dirty solvent 5 in the main storage section 26.
This is for returning the liquid to the solvent regeneration device 15 or discharging it to the waste liquid treatment tank 16.

The auxiliary storage part 26a surrounded by the tank wall 23, the partition walls 9 and 24, and the outer tank 1 has a solvent outlet 31 for circulation at the bottom of the tank, as can be clearly seen when FIG. 1 and FIG. 2 are combined. , 31 are provided. The solvent outlets 31, 31 are connected to a solvent circulation pump 33a and a filter 33, which constitute the circulation filtration mechanism 32.
It is connected to the solvent inlet 29 via b.

The solvent discharge port 30 is used to return the dirty solvent 5 to the solvent regeneration device 15 or directly to the waste liquid treatment tank 1.
This is for discharging the solvent 5 at 6.

Next, the last stage solvent cleaning tank 4 has four tank walls 34.
The main housing part 35 is surrounded by a tank wall 34.
has a solvent injection port 36 and a solvent supply port 3 at the bottom of the tank.
7 and a solvent outlet 38 are provided.

The solvent outlet 38 is similar to the solvent outlet 30,
Returning the dirty solvent 5 to the solvent regeneration device 15,
Alternatively, it is for directly discharging into the waste liquid treatment tank 16.

The solvent supply port 37 is connected to a solvent supply tank 39 containing fresh solvent and preferably to the solvent regeneration device 15 containing a regenerated liquid. That is, the solvent supply port 37 is filled with fresh solvent 5 or
It is for supplying the solvent 5 of the regenerated liquid that has been regenerated by distillation.

The auxiliary storage part 40 surrounded by the tank wall 34, the partition wall 25, and the outer tank 1 has a solvent outlet 4 at the bottom of the tank.
1,41 are provided. This solvent outlet 41, 41
is connected to the solvent inlet 36 via a pump 43a and a filter 43b that constitute a circulation filtration mechanism 42.

Further, the upper end of the tank wall 5 is higher than the upper end of the partition wall 25 by a predetermined height h7, and the predetermined height h7 is, for example, about 5 mm.

Main housing portions 10, 26 of solvent cleaning tanks 2, 3, 4,
As shown in FIG. 1, 35 is adapted to be attached with a rocking device S for rocking the carrier C (in the figure, the rocking device S is shown only on the solvent tank 4 for simplicity. ). In this carrier C, a large number of wafers W are arranged side by side.

In addition, each solvent cleaning tank 2, 3, and 4 is equipped with an ultrasonic cleaning device, a quantitative sensor for the solvent, a lower limit sensor, a sensor for preventing heating and controlling the temperature, and a pipe for removing air from the filter and a pipe for steam inlet and outlet. Although it is attached, it is omitted to simplify the drawing.

Next, the operation of the above-mentioned configuration will be explained.

First, the flow of the solvent 5 during the cleaning operation of the wafer W will be explained.

Fresh solvent 5 is supplied from the solvent supply tank 39 to the main storage section 35 of the last stage solvent cleaning tank 4 through the solvent supply port 37. At this time, a regenerating liquid (solvent 5) from which soluble impurities have been removed is also supplied from the solvent regenerating device 15 as required. The supplied solvent 5 fills the main storage part 35 and flows from the tank wall 34 to the auxiliary storage part 4.
It overflows to the 0 side in all directions (in the direction of arrow B in Figures 1 and 2).

The solvent 5 that overflowed from the main storage section 35 and was temporarily accommodated in the auxiliary storage section 40 overflows to the introduction section 27 side. The bottom portion of the solvent 5 in the auxiliary storage section 40 is returned from the solvent outlet 41 into the storage section 35 through the solvent inlet 36 via the pump 43a and the filter 43b. At this time, insoluble impurities are removed from the solvent 5 by the filter 43b.

On the other hand, the solvent 5 overflowing from the auxiliary storage section 40
moves to the introduction section 27 side of the solvent cleaning tank 3 and enters from the bottom of the main storage section 26 via the opening 28 to fill the main storage section 26. The solvent 5 overflowing from the main storage part 26 in all directions (in the direction of arrow D in FIG. 2) fills the auxiliary storage part 26a.

The solvent 5 that overflowed from the main storage portion 26 is
The solvent exits from the outlet 31 and is connected to the pump 33a and the filter 3.
After removing insoluble impurities via 3b,
The solvent is returned into the main storage portion 26 through the solvent injection port 39 .

Furthermore, the solvent 5 overflowing the auxiliary storage part 26a
moves to the introduction part 11 and passes through the opening 12 to fill the main storage part 10. The solvent 5 overflowing from the main storage part 10 in all directions (in the direction of arrow E in FIG. 2) moves to the auxiliary storage part 17. The solvent 5 stored in the temporary auxiliary storage part 17 comes out from the solvent outlet 18 and is pumped into the pump 20a.
After passing through the filter 20b and being cleaned, it is returned to the main storage portion through the solvent inlet 13.

Furthermore, the solvent 5 overflowing from the auxiliary storage section 17
The solvent is transferred to the discharge section 21 and returned to the solvent regeneration device 15 through the discharge port 22 as a used solvent.

Incidentally, the solvent purified by removing soluble impurities by distillation or the like in the solvent regenerating device 15 can be supplied from the solvent supply port 37 of the solvent cleaning tank 4 as a regenerating liquid.

The solvent cleaning operation of the wafer W in the flow of the solvent 5 as described above will be explained.

First, the carrier C on which a large number of wafers W are placed is placed on a swinging device S (not shown for simplicity) in the main storage part 10 of the solvent cleaning tank 2, and is immersed in the solvent 5. Ru.

The wafer W is cleaned by the solvent 5 while being rocked and irradiated with ultrasonic waves, and insoluble and soluble impurities are removed. Among these, insoluble impurities can be removed by the filter 20b of the circulation filtration mechanism 19.

Next, the carrier C is pulled up and placed in the swinging device S in the main storage section 26 of the solvent cleaning tank 3, which is an intermediate tank.
(not shown for simplicity) and soaked in solvent 5.

In the solvent cleaning tank 3, each wafer W is cleaned with the solvent 5 while being oscillated and irradiated with ultrasonic waves, in the same way as in the solvent cleaning tank 2, so that insoluble and soluble impurities fall off. . Among these, insoluble impurities can be removed by the filter 33b.

Further, the carrier C is transferred to the swinging device S in the main storage portion 35 of the solvent cleaning tank 4 and immersed in the solvent 5. Each wafer W is supplied with the cleanest solvent 5 sent from the solvent supply tank 39 or the solvent regeneration device 15.
(new solution or regenerated solution) is used for final cleaning to remove any remaining insoluble and soluble impurities.

Among these, insoluble impurities are filtered through the filter 43b.
removed by

In this way, the wafer W is immersed in the solvent baths 2, 3, and 4 in the order shown by the arrow A in FIG. Impurities are washed away. Then, the solvent 5 continuously flows stepwise (cascade type) in a direction opposite to the forward direction of cleaning the wafer W. Among these, insoluble impurities contained in the solvent 5 are removed from each filter 20b, 33 as described above.
b, 43b.

In addition, the soluble impurities contained in the solvent 5 are
The solvent passes through the solvent outlet 22 and is distilled off and purified by the solvent regenerating device 15.

The dirtiest solvent 5 in the solvent tank 2 is cleaned by the solvent regenerating device 15 through the outlet 22 .

By the way, since the openings 12 and 28 are largely opened at the bottom of each solvent cleaning tank 2, 3, and 4, the main storage parts 10, 26, and 3 of each solvent cleaning tank 2, 3, and 4 are
5. Insoluble and soluble impurities do not accumulate at the bottom.

Further, in the solvent cleaning device of the present invention, each of the solvent tanks 2, 3, and 4 is always filled with fresh liquid or the solvent regenerating device 15.
The regenerated liquid is circulated and the flow prevents the accumulation of impurities.

The solvent regeneration device may be separate from the solvent cleaning device or may be directly connected to the solvent cleaning tank as in the above embodiment, and if it is included in the circulation cycle of the solvent cleaning device of the present invention. , the effect of reducing the amount of solvent used is significant.

Note that the solvent cleaning apparatus of the present invention can be used to clean not only wafers but also other things.

Example 2 In Example 1 described above, the introduction section 11 and the main accommodating section 10 were connected through the opening 12, and the introduction section 27 and the main accommodating section 26 were connected through the opening 28.

On the other hand, the second embodiment shown in FIG. 3 differs from the first embodiment in the following points. That is, each bottom of the introduction part 11 and the main storage part 10 of the solvent cleaning tank 3 is connected to the pipe 100.
At the same time, the introduction part 27 of the solvent cleaning tank 4
This is the point where each bottom of the main storage portion 26 is connected by a pipe 120.

Effects of the Invention The solvent 5 in the main storage portions 26, 35 of each solvent cleaning tank 3, 4 overflows in all directions and is supplied from the bottom of the main storage portion 10, 26 of the preceding solvent cleaning tank 2, 3. The solvent 5 in the main storage parts 10, 26, 35 of each solvent cleaning tank 2, 3, 4 is stored in the circulation filtration mechanism 1.
9, 32, and 42, impurities do not remain in the solvent cleaning tanks 2, 3, and 4, and the solvent 5
can significantly reduce usage.

Further, impurities floating on the surface of the cleaning liquid in the cleaning tank 3 overflow in the direction of arrow D when the object to be cleaned is immersed or when the cleaning liquid overflows from the cleaning tank 4. At this time, the floating substances also flow into the introduction section 9 together with the cleaning liquid. In this state, the floating objects that enter the introduction section 9 are floating and have no way to go anywhere, but with the configuration of the present invention, the introduction section 9
and the main storage parts 10, 26, and 35 are connected to each other, and there is an auxiliary storage part 17 between the introduction part 9 and the main storage part. The cleaning liquid can also overflow into the auxiliary storage section 17. At this time, the floating matter in the introduction section 11 moves to the auxiliary storage section 17, and finally overflows from the auxiliary storage section 17 to the discharge section 21 and is discharged. Therefore, it is possible to prevent floating impurities from entering the main cleaning tank.

That is, the main storage part and the introduction part 11 are connected so that the fluid can be introduced, and the cleaning liquid can also overflow from the introduction part 11 when the object to be cleaned is immersed.
Therefore, the floating impurities are discharged without staying in the introduction section 11 or the auxiliary storage section 17, and without flowing into the main storage section.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing Embodiment 1 of the solvent cleaning device of the present invention, FIG. 2 is a plan view of Embodiment 1 of FIG. 1, and FIG. 3 is a sectional view showing Embodiment 2 of the invention. . G...Solvent cleaning tank group, 2, 3, 4...Solvent cleaning tank,
5...Solvent, 10,26,35...Main storage part, 15...
Solvent regeneration device, 17, 26a, 40... Auxiliary storage section, 20b, 33b, 43b... Filter.

Claims (1)

[Claims] 1. In a solvent cleaning device that cleans objects to be cleaned with a solvent, a plurality of solvent cleaning tanks are arranged, and the solvent supplied to the main storage part of the subsequent solvent cleaning tank overflows in all directions and passes through the auxiliary storage part. A group of solvent cleaning tanks configured to be sequentially supplied from the bottom of the main storage part of the solvent cleaning tank in the previous stage to fill the main storage part of the solvent supply tank in the previous stage;
a circulation filtration mechanism that circulates the solvent from the bottom of each of the auxiliary storage parts that temporarily stores overflowing solvent to the bottom of the main storage part of each corresponding solvent cleaning tank to filter out impurities; and a main storage part on the previous stage side. An introduction part for introducing fluid into the bottom of the main storage part on the front stage side due to the difference in wall height between the introduction part and the main storage part on the front stage side. 1. A solvent cleaning device characterized in that an auxiliary storage section is arranged to store the discharged solvent.