JPH06295896A - Cleaning equipment - Google Patents

Abstract

PURPOSE:To provide a cleaning equipment where the capacity of a cleaning tank itself is reduced by inclining the bottom of the tank and a straightener. CONSTITUTION:In a cleaning equipment wherein cleaning liquid is introduced into a cleaning tank 42 containing an object W to be treated from the bottom 52 thereof and straightened through a straightener 48 before cleaning the object W, the bottom part of the cleaning tank is inclined upward on the opposite sides thereof to form an inclining bottom part 60 while a corresponding horizontal straightening part 48A is formed in the center of the straightener and straightening parts 48B inclining upward are provided on the opposite sides. This structure allows reduction of the capacity of the cleaning tank 42 without causing any turbulence at the time of cleaning.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cleaning device.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing process, in order to remove a contaminant such as particles, organic contaminants, metal impurities, etc. adhered to the surface of an object to be processed, for example, a natural oxide film formed on the surface. Cleaning equipment is used in. This type of cleaning device is used for ammonia treatment, water washing treatment, hydrofluoric acid treatment,
For example, a chemical solution treatment and a water washing treatment such as a sulfuric acid treatment, a hydrochloric acid treatment, and a water washing treatment are alternately performed in sequence.

A cleaning device for treating a chemical liquid and a cleaning device for rinsing are generally of the same structure. For example, a chemical liquid or cleaning water is contained in a cleaning tank having a substantially flat bottom and a generally rectangular shape. Is satisfied, and a large number of wafers are arranged side by side, for example, 25
One wafer or 50 wafers were stored, and the chemical solution was supplied from the bottom to circulate the overflow liquid, or in the case of cleaning water, the contamination of the wafer surface was removed without circulating the overflowing cleaning water. In this case, in order to efficiently remove the contamination from the wafer surface and prevent it from adhering to the wafer surface again, the chemical solution and the cleaning water introduced into the tank are in a laminar flow state without causing turbulent flow. Therefore, it is necessary to flow upward between the wafers. For this reason, a flat plate-shaped straightening plate having a large number of through holes is provided at the bottom of the cleaning tank so as to be spaced slightly above the cleaning tank, so that efficient cleaning can be performed.

[0004]

However, in the above-described cleaning apparatus, the cleaning tank itself is formed in a substantially rectangular shape while the semiconductor wafer which is the object to be processed has a circular shape. Therefore, there is a problem that, for example, a dead space is generated on the side of the bottom, and the volume of the cleaning tank itself becomes larger than necessary. Further, for example, in the case of cleaning with a chemical solution, this chemical solution is relatively expensive, so the chemical solution overflowing from the tank is circulated and used, and if it becomes dirty to a certain extent, it is discarded. When the capacity is increased, the amount of chemical liquid to be used is increased, which causes a problem that operating cost is significantly increased.

Further, when cleaning a wafer treated with a chemical solution with cleaning water such as pure water, the introduced cleaning water is discarded when it overflows without being circulated.
This cleaning operation removes most of the chemical liquid adhering to the wafer surface when the specific resistance value of the cleaning water in the tank becomes more than a predetermined value due to the small number of ions mixed in it in the final rinse. It is carried out until it is considered that it has been eliminated. Therefore, as described above, when the capacity of the tank itself is large, the rate at which the cleaning water in the tank is replaced becomes slow, and the time required to reach the predetermined specific resistance value becomes long. There was also the problem that water had to be used.

In particular, as the mainstream of semiconductor wafers shifts from 6-inch size to 8-inch size and increases in diameter,
Since the capacity of the tank itself is increased, it is strongly desired to solve the above problems. The present invention has been made to pay attention to the above problems and to solve them effectively. An object of the present invention is to provide a cleaning device in which the bottom of the cleaning tank and the straightening vane are inclined to reduce the capacity of the tank itself without causing turbulent flow during cleaning.

[0007]

In order to solve the above problems, the present invention has a cleaning tank having an inlet for introducing a cleaning liquid at the bottom and containing an object to be cleaned, and the cleaning tank. In a cleaning device having a plurality of flow holes that are provided apart from the bottom of the cleaning liquid and through which the cleaning liquid passes, and a flow straightening plate that flows the cleaning liquid introduced from the inlet to the object side while rectifying the cleaning liquid, Both sides of the bottom portion of the cleaning tank have a bottom inclined portion that is inclined upward, and the straightening plate is a horizontal straightening portion that is horizontally corresponding to the central portion of the bottom portion and both sides of the horizontal straightening portion. It is configured to have an inclined rectifying portion which is provided and is inclined upward corresponding to the bottom inclined portion.

[0008]

Since the present invention is constructed as described above, both sides of the bottom portion of the cleaning tank are inclined upward to form inclined bottom portions, and the corresponding straightening plate portions are also inclined upwardly. Composed as a part. Therefore, the entire volume of the cleaning tank is reduced by the amount of inclination, and the amount of the chemical solution used for cleaning the object to be treated or the amount of pure water used for the cleaning can be significantly suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cleaning apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. 1 is a cross-sectional view showing an embodiment of the cleaning device of the present invention, FIG. 2 is a partially cutaway perspective view showing the cleaning device of the present invention, FIG. 3 is a plan view showing a current plate used in the device shown in FIG. 4 is a schematic side sectional view of the apparatus shown in FIG. 2, and FIG. 5 is a perspective view showing a cleaning apparatus collecting unit in which a plurality of the cleaning apparatuses shown in FIG. 2 are collected.

In this embodiment, the case where the cleaning device is applied to a chemical cleaning device or a water cleaning device will be described. First, a cleaning device collecting unit formed by collecting cleaning devices according to the present invention will be described with reference to FIG. As shown in FIG. 5, the cleaning device assembly unit 2 includes an input buffer mechanism 4 for receiving an object to be processed before cleaning, for example, a semiconductor wafer W in a cassette unit and storing the cassette C, and an input buffer mechanism 4 from the input buffer mechanism 4. A loader mechanism 6 that receives the semiconductor wafers W in cassette units, a cleaning processing mechanism 10 that performs cleaning processing such as chemical treatment and water cleaning on the semiconductor wafers W transferred from the loader mechanism 6 by the wafer transfer device 8, and this cleaning. Processing mechanism 10
The unloader mechanism 12 for unloading the semiconductor wafer W processed by the unloader mechanism 12 and the output buffer mechanism 14 for receiving and storing the semiconductor wafer W in cassette units from the unloader mechanism 12.

A cassette cleaning / drying line 18 for cleaning and drying an empty cassette C after the semiconductor wafer W is taken out by the wafer transfer device 8 is provided above the cleaning processing mechanism 10. It is arranged along 10. Then, the cassette cleaning / drying line 18 is configured to lift and supply an empty cassette C from the loader mechanism 6 via an elevating mechanism 20. Further, a similar lifting mechanism (not shown) is also provided on the unloader mechanism 12 side, and washing and cleaning are performed via this lifting mechanism.
The cassette C after drying is configured to be supplied to the unloader mechanism 12.

The input buffer mechanism 4
Is a mounting portion 2 for mounting the cassette C supplied from the outside.
2 and a cassette storage unit 26 for temporarily storing the cassette C that cannot be processed immediately by transferring the cassette C of the mounting unit 22 by the cassette transport mechanism 24. Further, the cassette carrying mechanism 24 transfers the cassette C from the placing unit 22 to the loader mechanism 6 when processing the semiconductor wafer W in the cassette C placed on the placing unit 22. Is configured. And
The loader mechanism 6 is provided with a position adjusting mechanism (not shown) for aligning the orientation flat of the semiconductor wafer W to the upper side or the lower side, for example. The output buffer mechanism 14 is also constructed similarly to the input buffer mechanism 4.

The cleaning processing mechanism 10 is, for example,
The wafer transfer device 8, a chuck cleaning / drying treatment tank 28 for cleaning and drying the wafer chuck 8A of the wafer transfer device 8, and a semiconductor wafer W which is sequentially arranged on the downstream side of the chuck cleaning / drying treatment tank 28. The chemical cleaning device 30 for removing unnecessary substances such as organic contaminants on the surface, metal impurities or particles by cleaning, the two cleaning cleaning devices 32, 32 for cleaning the semiconductor wafer W after the chemical processing, and the chemical cleaning device 30. A chemical cleaning device 34 for performing another chemical liquid processing, two water cleaning / cleaning devices 36, 36, and a chuck cleaning / drying treatment tank 3 for cleaning and drying the wafer chuck 8A.
8 and a semiconductor wafer W from which impurities have been removed are vapor-dried with, for example, isopropyl alcohol (IPA) or the like, and a drying treatment tank 40 is provided. The chemical cleaning devices 30, 34 and the water cleaning devices 32, 34 are
Each processing liquid overflows, and the overflowed processing liquid is discharged or circulated to remove accumulated impurities and is circulated for reuse. Also, as shown in FIG. The current plate is tilted upward.

As shown in FIG. 5, three wafer transfer devices 8 are arranged so as not to be affected by the chemical cleaning devices 30 and 34. Each of the wafer transfer devices 8 includes, for example, a pair of left and right wafer chucks 8A that collectively hold 50 semiconductor wafers W, and a drive mechanism (not shown) that moves the wafer chucks 8A up and down and moves the wafer chucks 8A back and forth. ) And a transfer base 8B arranged along the processing tanks 28 to 40, and is configured to reciprocate along the transfer base 8B.

Further, as shown in FIG. 4, the cleaning device, for example, the chemical cleaning device 30, has a rectangular cleaning tank 42 for storing a treatment liquid such as ammonia water heated to a high temperature,
A wafer holder 44 is provided in the cleaning tank 42 for vertically holding, for example, 50 semiconductor wafers W, and a plurality of through holes 46 are provided slightly below the wafer holder 44, that is, slightly above the bottom. And a supply pipe 50 for supplying a cleaning liquid such as a chemical liquid to the rectifying plate 48 from below. Further, the supply pipe 50 is provided at two inlets 5 of the bottom portion 52 of the cleaning tank 42.
4, 54 is configured to supply the cleaning liquid, and
Dispersion plates 56, 56 are disposed slightly above the respective inlets 54, 54, and the cleaning liquid is dispersed by the dispersion plates 56, 56 toward the entire surface of the straightening plate 48. Further, the rectifying plate 48 is supported by being separated from the bottom portion 52 by a support column 58 standing upright from the bottom portion 52.

More specifically, as shown in FIGS. 1 and 2, both sides of the bottom portion 52 of the cleaning tank 42 face upward at an angle θ1 along the width direction of the cleaning tank 42, that is, the surface expansion direction of the wafer W. It is inclined to form the bottom inclined portion 60. In the illustrated example, the central portion of the bottom portion is horizontal, but the bottom portion may be formed without being formed so as to be directly inclined upward from the center portion of the bottom portion. And this bottom 5
The rectifying plate 48 located at a distance L1 smaller than 2, for example, 20 mm above is also deformed in the same manner as the bottom portion 52, and the portion corresponding to the center of the bottom portion 52 is formed as a horizontal rectifying portion 48A which is horizontal, The both sides are the above-mentioned bottom sloped part 6
The tilt rectifying portion 48B is also tilted upward at an angle θ2 in correspondence with 0. In this case, the respective inclination angles θ1 and θ2 are preferably set to the same angle, for example, 30 degrees so as to be parallel to each other so that the flow passage area becomes constant. By thus tilting both sides of the bottom portion 52 and the current plate 48 upward, it is possible to reduce the dead space in the tank and reduce the internal volume of the tank.

Then, as shown in FIG.
In the horizontal rectifying section 48 of the
For example, 31 rows are formed in the tank length direction, and in each of the tilt rectification sections 48B, 48B, 11 inclined section flow holes 46B are formed, for example, in 3 rows in the horizontal direction. In this case, the diameter D1 of the horizontal portion circulation hole 46A is, for example, 5.6 m.
m, and the diameter D2 of the inclined portion circulation hole 46B is set to, for example, 3.4 mm. Therefore, the area of all the horizontal portion circulation holes 46A of the horizontal flow passage portion 48A of the flow regulating plate 48 and one of the inclined rectification portions The ratio of the areas of all the inclined portion circulation holes 46B of 48B is set to about 10: 1. Here, the area ratio of all the circulation holes, the total number of circulation holes, and the inclination angles θ1 and θ2 of the bottom inclined portion 60 and the inclination rectifying portion 48B of the cleaning tank 42.
Needless to say, is not limited to the above value.

The materials of the cleaning tank 42 and the rectifying plate 48 depend on the type of cleaning liquid used. For example, in the case of a chemical cleaning device that uses highly reactive sulfuric acid or ammonia water, both are corrosion resistant. In the case of a washing and washing apparatus using strong quartz or the like and pure water, polyvinyl chloride or the like can be used. In particular, when quartz is used as the material, the workability is very poor, so that dimensioning and the like are difficult, and it is difficult to bring the inner wall 42A of the cleaning tank 42 and the end surface of the detachable rectifying plate 48 into close contact with each other. This cannot be done, and a slight gap S having a distance of, for example, about 1 mm is unavoidable between them.

Further, the drilling direction Y of the inclined portion flow holes 46B formed in the inclined rectifying portions 18B, 18B is not the height direction of the cleaning tank 42 but a direction substantially orthogonal to the surface direction of the inclined rectifying portion 18B. It is preferable to set it so that the flow in the flow hole 46B can be smoothed. Reference numeral 62 in FIG. 4 is an overflow tank provided at the upper peripheral edge of the cleaning tank 42. The overflowed cleaning liquid may or may not be circulated as necessary, and a final rinse with pure water is performed. At times, the specific resistance value of this overflow liquid will be measured.

Next, the operation of this embodiment will be described.
First, when the semiconductor wafers W stored in the cassette C in units of 25 sheets are supplied to the mounting portion 22 of the input buffer mechanism 4, the cassette transfer mechanism 24 is driven to supply the supplied cassettes C in units of two and the loader mechanism 6 is supplied. Transfer to. And
The cassette C supplied thereafter is transferred to the storage unit 26 by the cassette transfer mechanism 24, and the semiconductor wafer W of the subsequent cassette C is temporarily stored in the storage unit 26.

When two cassettes C are supplied to the loader mechanism 6, the loader mechanism 6 is driven to drive the two cassettes C.
While aligning the orientation flats of the semiconductor wafers W in one direction in one direction to position the 50 semiconductor wafers W, the wafer transfer device 8 is driven to move the wafer chuck 8A into the chuck cleaning / drying processing tank 28 to move the wafers. The chuck 8A is washed and dried, and the loader mechanism 6 is ready to receive the semiconductor wafer W. Thereafter, the loader mechanism 6 is driven to bring the semiconductor wafers W of the two cassettes C together to bring the semiconductor wafers W of the respective cassettes C closer together, and the wafer transfer device 8 is driven to drive the wafer chuck 8A.
50 semiconductor wafers W are gripped. Semiconductor wafer W
The wafer chuck 8A that grips the wafer cleaning device 30 is driven by the wafer transfer device 8 to move along the transfer base 8B.
After that, the wafer chuck 8A is lowered at that position, and 50 semiconductor wafers W are handed over to a wafer holder (not shown) in the chemical cleaning device 30 and immersed in the processing liquid. In this chemical liquid cleaning device 30, since the cleaning liquid is supplied from the supply pipe 50, the supplied cleaning liquid is dispersed over the entire surface of the rectifying plate 48 by the distribution plates 56, 56 of the two inlets 54, 54. From each of the circulation holes 46 to flow into the semiconductor wafer W side substantially evenly.

At this time, the cleaning liquid dispersed by the dispersion plate 56 reaches the horizontal rectifying portion 48A of the rectifying plate 48 and passes upward through the horizontal portion flow hole 46A, while the bottom inclined portion 60 inclined upward and the inclined rectification. The wafer W flows through the flow path between the wafer W and the inclined portion circulation hole 46B.
Pass in the direction. The cleaning liquid that has passed through the flow holes flows between the wafers in a laminar flow state, and cleans and removes impurities such as various particles adhering to the wafer surface. When the cleaning liquid overflowing from the cleaning tank 42 is treated with a chemical solution as in the present embodiment, after cleaning, it is guided to the bottom supply pipe 50 and circulated for use. When cleaning with pure water as in a water cleaning cleaning device, overflow occurs. Discard the washed water as it is.

Here, in this embodiment, both sides of the bottom portion 52 of the cleaning tank 42 are tilted upward to form the bottom inclined portion 60, and correspondingly, both sides of the straightening plate 48 are also inclined upward to incline the straightening portion. Cleaning tank 4 because 48B was formed
It is possible to reduce the total volume of 2 itself by that amount, and therefore it is possible to significantly reduce the amount of the cleaning liquid such as the chemical liquid or pure water used. Taking an 8-inch wafer cleaning apparatus as an example, the apparatus of the present invention can reduce its capacity by about 10% as compared with the conventional apparatus.

Further, the time for replacing the cleaning liquid is shortened, so that efficient cleaning can be performed. For example, when the present embodiment is applied to a water washing / cleaning apparatus, the specific resistance value of overflow washing water for inspecting the degree of wafer washing reaches a predetermined value, for example, 15 MΩ in a short time, and the water washing is performed efficiently. You can This state is shown in FIG.
In the figure, a curve A shows a little characteristic when the device according to the present invention is used, and a curve B shows a characteristic when the conventional device is used. It can be seen that the time required to reach a specific resistance value of 15 MΩ indicating the completion of the final rinse with pure water is considerably faster in the case of the device of the present invention shown in the curve A than in the case of the curve B of the conventional device.

It is also conceivable to form the current plate 48 in a flat plane shape without inclining it.
In this case, since the flow passage area formed between the straightening vane 48 and the bottom inclined portion 60 becomes gradually narrower, it passes through the gap S formed between the end of the straightening vane and the tank inner wall 42A. The flow rate of the cleaning liquid flowing relatively increases, and turbulent flow easily occurs in the cleaning liquid rising in the tank, which is not preferable. On the other hand, in the present embodiment, as described above, the bottom sloped portion 60
Since the inclination rectifying section 48B and the rectifying section 48B are inclined at the same angles θ1 and θ2, the flow passage areas in the liquid flow direction are the same, and as a result, the cleaning liquid smoothly passes through the inclined portion flow holes 46B in the wafer W direction, The amount of liquid flowing through the gap S between the inner wall 42A and the end of the current plate can be greatly suppressed, and the generation of turbulence can be significantly suppressed. At this time, the drilling direction Y of the inclined portion circulation hole 46B is set not at the tank height direction but at a substantially right angle to the surface of the current plate, so that the cleaning liquid is passed through the circulation hole 46B.
B can flow more smoothly to B, and the occurrence of turbulence can be further suppressed. In addition, this inclined portion flow hole 46B
If the hole diameter is set to be excessively large, the cleaning liquid is often entrained inside the wafer, and normal cleaning cannot be performed, which is not preferable, and the area of the entire horizontal portion flow holes 46A and the entire inclined portion of one inclined rectifying portion 48B are not achieved. The area ratio of the circulation holes 46B is
It is preferably set to about 30: 1 or less.

When the processing of the semiconductor wafer W in the chemical cleaning device 30 is completed as described above, the wafer chuck 8A of the wafer transfer device 8 batches the semiconductor wafers W from the wafer holder 44 by the operation reverse to that described above. And then receive
Then, the wafer is transferred to the wafer holder of the next washing / cleaning device 32, and the washing process is performed by the same operation as described above. Further, the same washing process is performed by the next washing / cleaning device 44 to complete the washing process. Thereafter, the chemical solution treatment and the water washing treatment are repeatedly performed as needed, and the wafer W after the washing treatment is discharged to the next process via the output buffer mechanism 14 in a cassette unit. In the above embodiments, the chemical cleaning device was mainly described, but it goes without saying that the same can be applied to a water cleaning device.

[0027]

As described above, according to the cleaning apparatus of the present invention, the following excellent operational effects can be exhibited. Since the bottom of the cleaning tank is tilted and the rectifying plate is also tilted correspondingly, the capacity of the cleaning tank can be reduced without causing turbulence in the cleaning liquid during cleaning. Therefore, it is possible to reduce the amount of the cleaning liquid such as the chemical liquid or pure water used, and it is possible to significantly reduce the running cost. Further, since the replacement speed of the cleaning liquid in the cleaning tank is high, rapid cleaning can be performed, and particularly in the case of cleaning with pure water, the recovery of the specific resistance value can be accelerated.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a cleaning apparatus of the present invention.

FIG. 2 is a partially cutaway perspective view showing a cleaning device of the present invention.

FIG. 3 is a plan view showing a current plate used in the apparatus shown in FIG.

FIG. 4 is a schematic side sectional view of the device shown in FIG.

5 is a perspective view showing a cleaning device assembly unit in which a plurality of cleaning devices shown in FIG. 2 are assembled.

FIG. 6 is a graph showing changes in the specific resistance value during cleaning by the device of the present invention and the conventional device.

[Explanation of symbols]

 30, 34 Chemical cleaning device 32, 36 Water cleaning device 42 Cleaning tank 46 Flow hole 46A Horizontal part flow hole 46B Slope flow hole 48 Straightening plate 48A Horizontal straightening plate 48B Sloping straightening plate 52 Bottom 54 Inlet 56 Dispersing plate 60 Bottom slanting Part W Semiconductor wafer (Processing object)

Claims (2)

[Claims] 1. A cleaning tank having an inlet for introducing a cleaning liquid at its bottom and containing an object to be cleaned, and a large number of through holes provided separately from the bottom of said cleaning tank and through which said cleaning liquid passes. In the cleaning device having a rectifying plate that flows toward the object to be processed while rectifying the cleaning liquid introduced from the inlet, both sides of the bottom of the cleaning tank have a bottom inclined portion inclined upward. The straightening plate has a horizontal straightening portion horizontally arranged corresponding to a central portion of the bottom portion, and inclined straightening slants provided on both sides of the horizontal straightening portion and inclined upward corresponding to the bottom slanting portion. A cleaning device having a portion. 2. The cleaning apparatus according to claim 1, wherein the bottom sloped portion is parallel to the slope rectification portion.