JP2022176545A - Cleaning processing device - Google Patents

Abstract

To provide a cleaning processing device that has high cleaning effect and can suppress occurrence of reattachment of foreign substances once removed.SOLUTION: A cleaning processing device has a cleaning liquid supply mechanism for supplying a cleaning liquid to a surface to be cleaned of a wafer and a rotatable cleaning brush that is arranged opposite the surface to be cleaned and cleans the surface to be cleaned with a brush. The cleaning brush has a rotatable brush head, and a plurality of brush bodies arranged on a brush mounting surface of the brush head facing the surface to be cleaned of the wafer. A material of the plurality of brush bodies is fluororesin, each cross-sectional shape being any of a semicircular shape, L-shaped, a rectangular shape, a triangular shape, and heart-shaped. They are arranged in a radial or a spiral shape with respect to a center of the brush mounting surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cleaning processing apparatus that supplies a cleaning liquid to a surface of a wafer to be cleaned and performs brush cleaning.

2. Description of the Related Art During the manufacturing process of semiconductor wafers and the like, brush cleaning is performed using a cleaning brush in order to remove foreign matter adhering to the surface of the wafer (Patent Document 1). For example, when brush cleaning a wafer immediately after polishing, it is common to treat the wafer with ozone water to form an oxide film, and then perform brush cleaning with pure water or SC1 solution using a cleaning apparatus.

As shown in FIG. 11, the conventional cleaning processing apparatus 101 includes a cleaning liquid supply mechanism 102 for supplying the above cleaning liquid to the surface of the wafer W to be cleaned, and a cleaning liquid supply mechanism 102 arranged opposite to the surface of the wafer W to be cleaned. and a cleaning brush 103 for cleaning the surface to be cleaned.
The cleaning brush 103 has a brush head 105 and a brush body 106 fixed to the brush head 105 . On the wafer W, the brush head 105 rotates (rotates on its own axis) and can be moved in parallel in any left or right direction.

12 and 13 show examples of brush bodies in conventional cleaning brushes. There are cases where only one brush body is provided for the brush head as shown in FIG. 12, and there are cases where a plurality of brush bodies are provided as shown in FIG. It is cylindrical. That is, the cross-sectional shape of the brush body is circular.
Also, the material of the brush body is generally PVA.

When the surface of the wafer to be cleaned is brush-cleaned, the wafer is rotated and the rotating brush head is moved to bring the brush body of the cleaning brush into contact with the wafer while supplying the cleaning liquid onto the wafer. Remove any foreign matter that may be present. The cleaning is performed while moving the wafer and the brush head so that the brush body of the cleaning brush comes into contact with the entire surface of the wafer to be cleaned.

JP-A-10-92780

In the conventional cleaning apparatus as described above, when brush cleaning is performed using hydrofluoric acid (HF) or ozone water to improve the cleaning performance, ozone water is used to re-form the oxide film after the HF process. processing is required. If PVA is used as the brush body of the cleaning brush, the brush body may be damaged by the ozone water, resulting in breakage.
Further, there is a problem that the brush body made of PVA has a low cleaning ability (ability to remove foreign matters).

In addition, as described above, conventional cleaning brushes have a single brush body with no arrangement pattern on the brush head. ). In this case, there is a problem that the foreign matters removed by the brush body are not smoothly removed from the wafer and reattached to the wafer.
FIG. 14 is an explanatory view showing the positions of a range in which foreign matter can be removed (removal effect range) and a range in which reattachment of the removed foreign matter occurs (reattachment range) in the cylindrical brush body of the cleaning brush. be. The cleaning effect (foreign matter removal effect) is only near the edge on the front side with respect to the direction of movement (the direction of rotation of the brush head). Due to the shortage of the cleaning liquid, foreign matter reattaches to the wafer.

In addition, if the arrangement pattern of the brushes is not appropriate, the cleaning liquid cannot be drained efficiently, and the cleaning liquid stays around the brushes. I have a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cleaning apparatus which has a high cleaning effect and can suppress re-adhesion of foreign matter once removed.

In order to achieve the above object, the present invention provides a cleaning liquid supply mechanism that supplies a cleaning liquid to a surface to be cleaned of a wafer, and a rotatable cleaning device that is arranged opposite to the surface to be cleaned and performs brush cleaning of the surface to be cleaned. A cleaning treatment apparatus comprising a brush,
The cleaning brush has a rotatable brush head and a plurality of brush bodies arranged on a brush arrangement surface of the brush head facing the surface to be cleaned of the wafer,
The plurality of brush bodies are
The material is fluororesin,
each having a semicircular, L-shaped, rectangular, triangular, or heart-shaped cross-sectional shape;
The cleaning apparatus is characterized in that the brushes are arranged radially or spirally with respect to the center of the brush arrangement surface.

As described above, in the cleaning apparatus, if the material of the brush body of the cleaning brush is fluororesin, the brush body can be prevented from being damaged and broken even when the cleaning liquid is ozone water. Brush cleaning can be performed even under water. For example, brush cleaning with HF and brush cleaning with ozone water can be alternately performed, and the cleaning performance can be improved.
In addition, if the cross-sectional shape of the brush body is as described above, unlike the conventional brush body with a circular cross-sectional shape, it is possible to prevent the redeposition range from occurring due to lack of cleaning liquid, and substantially It can only have a removal effect range. Therefore, it is possible to suppress reattachment of the foreign matter once removed.
Further, since the arrangement pattern of the brush bodies is as described above, the cleaning liquid taken in under the cleaning brushes can be drained smoothly. Therefore, it is possible to prevent the cleaning liquid from stagnation under the cleaning brush, and it is possible to suppress reattachment of the removed foreign matter caused by the stagnation.

Also, the plurality of brush bodies may be made of any one of PTFE, PCTFE, PVDF, PVF, PFA, FEP, ETFE, and ECTFE.

With such a material, it is possible to more reliably clean the brush under ozone water without damaging the brush body.

Further, each of the plurality of brush bodies may be a bundle of hollow fibers or a foam.

With such a structure, the ability to remove foreign matter can be further improved.

Further, the cleaning liquid can be any one of pure water, SC1 liquid, hydrofluoric acid, and ozone water.

In this way, pure water and SC1 liquid can be used in the same manner as in the prior art, and hydrofluoric acid and ozone water can also be used in addition to these, so that the cleaning performance can be further improved.

Also, the wafer may be a polished silicon wafer.

Thus, the cleaning apparatus of the present invention is particularly effective for cleaning polished silicon wafers.

Further, each of the plurality of brush bodies may be disposed in such a direction that the cross-sectional shape thereof is oblong when the rotational direction of the rotatable brush head is the vertical direction.

With such a configuration, it is possible to more reliably have only a foreign matter removal effective range, and it is possible to further effectively suppress reattachment of foreign matter.

As described above, with the cleaning apparatus of the present invention, it is possible to improve the cleaning effect and suppress the occurrence of reattachment of removed foreign matter.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of the cleaning processing apparatus of this invention. It is explanatory drawing which shows an example of the semi-circular cross-sectional shape of a brush body. It is explanatory drawing which shows an example of the L-shaped cross-sectional shape of a brush body. It is explanatory drawing which shows an example of the rectangular cross-sectional shape of a brush body. It is explanatory drawing which shows an example of the triangular cross-sectional shape of a brush body. It is explanatory drawing which shows an example of the heart-shaped cross-sectional shape of a brush body. FIG. 5 is an explanatory diagram showing an example of a removal effect range in the case of a brush body having a semicircular cross-sectional shape; FIG. 4 is an explanatory diagram showing an example of a radial arrangement pattern; FIG. 4 is an explanatory diagram showing an example of a spiral arrangement pattern; FIG. 4 is an explanatory diagram in plan view showing an example of the arrangement direction of the brush body with respect to the rotation direction (rotation direction) of the brush head when the cross-sectional shape of the brush body is rectangular. It is a schematic diagram showing an example of a conventional cleaning treatment apparatus. It is a schematic diagram showing an example of the shape of a brush body in a conventional cleaning brush. FIG. 5 is a schematic diagram showing another example of the shape of a brush body in a conventional cleaning brush; FIG. 5 is an explanatory diagram showing an example of positions of a foreign matter removal effect range and a foreign matter reattachment range in a cylindrical brush body. The left side shows the position of the cleaning brush when viewed from the side, and the right side shows the position of the brush body in plan view.

As described above, in the wafer cleaning apparatus that uses a cleaning brush for brush cleaning, there have been problems of low cleaning performance and reattachment of foreign matter. Therefore, the present inventors conducted extensive research, and found that the plurality of brush bodies in the cleaning brush are made of fluororesin, and each has a semicircular, L-shaped, rectangular, triangular, or heart-shaped cross section. If it is arranged radially or spirally with respect to the center of the brush arrangement surface, it is possible to wash the brush under ozone water and improve the washing ability. In addition, the inventors have found that it is possible to suppress re-adhesion of foreign matter, and completed the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 shows an example of the cleaning apparatus of the present invention. A cleaning processing apparatus 1 is a single-wafer type apparatus, and includes a cleaning liquid supply mechanism 2 and a cleaning brush 3 . It also has a wafer holder 4 for holding a wafer W to be cleaned.

Wafers to be cleaned by the cleaning apparatus 1 of the present invention are not particularly limited, and include various semiconductor wafers such as semiconductor silicon wafers and compound semiconductor wafers, and particularly polished silicon wafers. In addition, the apparatus can also clean various wafer-like objects such as glass substrates.

The wafer holder 4 is rotatable by a drive source (not shown), and the rotation of the wafer holder 4 allows the held wafer W to rotate. For example, the same one as conventional can be used.
Also, the cleaning liquid supply mechanism 2 can be, for example, a nozzle as shown in FIG. This nozzle supplies a cleaning liquid to the surface to be cleaned S of the wafer W held by the wafer holder 4 . Examples of the cleaning liquid include pure water and SC1 liquid, which have been generally used for cleaning. Furthermore, it is also capable of supplying HF and ozone water. As will be described later, the cleaning brush 3 of the present invention is particularly resistant to ozone water, and HF and ozone water may be supplied alternately during cleaning of the brush in order to improve the cleaning performance and to re-form the oxide film. can.
Although an example of nozzles has been described as the cleaning liquid supply mechanism 2 , it may be integrated with the cleaning brush 3 so that the cleaning liquid can be discharged from the lower center of the cleaning brush 3 .

The cleaning brush 3 is positioned above the wafer W and arranged to face the surface S of the wafer W to be cleaned. A brush head 5 having a brush arrangement surface B facing the surface S to be cleaned and a plurality of brush bodies 6 arranged on the brush arrangement surface B are provided. Then, the brush body 6 is brought into contact with the surface S to be cleaned to perform brush cleaning.

The brush head 5 is rotatable by a driving source (not shown), and when the brush head 5 rotates, the brush body 6 fixedly arranged on the brush installation surface B rotates together.

The material of the brush body 6 is fluororesin. A conventional PVA brush body may be damaged and broken under ozone water. However, the brush body 6 made of fluororesin as in the present invention is resistant to ozone water and is not damaged or broken unlike conventional products. Therefore, it is also possible to perform brush cleaning using HF and ozone water alternately. In this case, for example, PTFE, PCTFE, PVDF, PVF, PFA, FEP, ETFE, ECTFE, etc. are selected so that the brush can be washed more reliably under ozone water without damaging the brush body 6. be able to.
In addition, compared with PVA, fluororesin has a higher cleaning ability.

Moreover, each of the brush bodies 6 can be made of, for example, a bundle of hollow fibers. Although the number of wires per bundle is not particularly limited, it can be, for example, several tens to several hundred. A foam can also be used instead of the bundle of hollow fibers. If it is something like these, it is possible to further improve the ability to remove foreign matter.

The shape of the brush body 6 is also characteristic. The brush body 6 of the present invention has a semicircular, L-shaped, rectangular, triangular, or heart-shaped cross section, whereas the conventional device has a cylindrical shape, that is, a circular cross section. It is. Examples of these shapes are shown in FIGS. 2-6.
Here, in the case where the cross-sectional shape is circular as in the conventional art, as shown in FIG. However, due to the shortage of the cleaning liquid, a redeposition range is generated in which the removed foreign matter is re-adhered.
On the other hand, in the case of the present invention, since the shape is not circular but semicircular or the like, as shown in FIG. 7, the shape substantially has only the removal effect range, and the generation of the reattachment range can be suppressed. Therefore, it is possible to suppress re-adhesion of the once-removed foreign matter, which is a problem in the conventional cleaning apparatus.
Although FIG. 7 shows an example of a semicircular shape, other shapes (L-shaped, rectangular, triangular, and heart-shaped) also have only a removal effect range.

A plurality of brush bodies 6 as described above are arranged side by side on the brush arrangement surface B of the brush head 5, and the arrangement pattern thereof is radial or spiral with respect to the center of the brush arrangement surface B. It's becoming FIG. 8 shows a radial arrangement pattern, and FIG. 9 shows a spiral arrangement pattern (top left corner, respectively). An example in which the cross-sectional shape of the brush body 6 shown in FIG. 2-6 is provided is also shown.
Due to the radial or spiral arrangement pattern, the cleaning liquid trapped between the cleaning brush 3 (brush head 5) and the wafer W during cleaning can be efficiently discharged. That is, the foreign matter removed by brush cleaning using the cleaning brush 3 can be smoothly discharged together with the cleaning liquid. Therefore, it is possible to prevent the cleaning liquid from staying between the cleaning brush and the wafer W. FIG. Therefore, it is possible to prevent the removed foreign matter from adhering again due to the retention of the cleaning liquid.

The number of brush bodies 6 arranged on the brush arrangement surface B is not particularly limited as long as it is plural. It can be appropriately determined depending on the size of the brush arrangement surface B, the size of each brush body 6, the type of wafer W to be cleaned, the type of cleaning liquid, and the like.

Also, the method of arranging the brush body 6 on the brush arranging surface B is not particularly limited. It is preferable that they are arranged in different directions. Here, as an example, FIG. 10 shows the arrangement direction of the brush body 6 with respect to the rotation direction (rotation direction) of the brush head 5 when the cross-sectional shape of the brush body 6 is rectangular. As shown in the plan view of FIG. 10, when the rotation direction of the brush head 5 is the vertical direction (upward direction in the drawing), the long side of the rectangle (cross-sectional shape) is in the horizontal direction (left-right direction in the drawing). In addition, the brush body 6 is arranged so that the cross-sectional shape as a whole becomes horizontally long. Although an example in which the long sides are arranged perpendicularly to the direction of rotation of the brush head 5 has been shown, the angle may of course be shifted and the brush head 5 may be slanted. Similarly, in the case of other cross-sectional shapes, each brush body 6 can be arranged in a laterally long direction. With such an orientation, it is possible to more reliably have only the removal effect range and not to have the reattachment range, so that the reattachment of foreign matter can be more effectively suppressed.

An example of a cleaning process including brush cleaning of a wafer using the cleaning apparatus 1 of the present invention as described above will be described.
First, for example, a wafer W (silicon wafer, etc.) is prepared which has been subjected to polishing treatment, and then subjected to ozone water treatment to decompose and remove the organic matter of the abrasive adhering to the surface and to form an oxide film. It is held by the wafer holder 4 .

While supplying HF as a cleaning liquid to the surface S to be cleaned from the nozzles of the cleaning liquid supply mechanism 2, the brush body 6 of the cleaning brush 3 is brought into contact with the surface S to be cleaned to perform brush cleaning. At this time, by rotating the cleaning brush 3 and moving it parallel on the wafer W, the entire surface S to be cleaned is brush-cleaned.
The concentration of HF to be supplied can be, for example, 1.0% by mass or less, but is not particularly limited.
The cleaning treatment time is preferably set to a time during which the oxide film is removed and the bare surface is not exposed. For example, it can be 5 seconds or more and 60 seconds or less.
The HF flow rate can be, for example, 0.8 L/min or more and 4.0 L/min or less.
Although the number of rotations of the cleaning brush 3 is not particularly limited, it can be, for example, 5 rpm or more and 200 rpm or less.

During this brush cleaning, the wafer W itself may be rotated or may not be rotated. When rotating, the spin rotation speed of the wafer W can be, for example, 5 rpm or more and 60 rpm or less. The rotation direction of the wafer W is not particularly limited. The rotating direction of the cleaning brush 3 is not particularly limited. For example, the spin direction of the wafer W can be CCW (counterclockwise), and the rotation direction of the cleaning brush 3 can be CW (clockwise). Alternatively, both can be clockwise or counterclockwise.

Next, brush cleaning is performed by supplying ozone water instead of HF.
The concentration of the supplied ozone water can be, for example, 10 ppm or more and 50 ppm or less.
The washing time can be, for example, 10 seconds or more and 180 seconds or less.
The ozone water flow rate can be 0.8 L/min or more and 4.0 L/min or less.
Although the number of rotations of the cleaning brush 3 is not particularly limited, it can be, for example, 5 rpm or more and 200 rpm or less.
The rotation of the wafer W itself can be performed in the same manner as in the brush cleaning with HF, for example.
It is preferable that the oxide film thickness formed in this step be 0.8 nm or more and 1.5 nm or less.

Such brush cleaning with HF and brush cleaning with ozone water can be alternately repeated as necessary. The washing conditions for each cycle may be the same, or may be different from each other.

It should be noted that brush cleaning may be performed using pure water or SC1 liquid at an appropriate timing as necessary. After performing brush cleaning using the cleaning apparatus 1 of the present invention as described above, for example, spin cleaning or batch cleaning can be performed as finish cleaning. During these cleanings, especially after the oxide film is removed using HF, the re-oxidized film can be formed using ozone water.

By the cleaning treatment process as described above, the foreign matter is efficiently removed, the re-adhesion of the foreign matter is suppressed, and the wafer W with high cleanliness can be obtained.

It should be noted that the present invention is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present invention and produces similar effects is the present invention. It is included in the technical scope of the invention.

DESCRIPTION OF SYMBOLS 1... Cleaning processing apparatus of this invention, 2... Cleaning liquid supply mechanism, 3... Cleaning brush,
4 Wafer holder 5 Brush head 6 Brush body
B... brush arrangement surface, S... surface to be cleaned, W... wafer.

Claims (6)

A cleaning processing apparatus comprising: a cleaning liquid supply mechanism for supplying a cleaning liquid to a surface to be cleaned of a wafer;
The cleaning brush has a rotatable brush head and a plurality of brush bodies arranged on a brush arrangement surface of the brush head facing the surface to be cleaned of the wafer,
The plurality of brush bodies are
The material is fluororesin,
each having a semicircular, L-shaped, rectangular, triangular, or heart-shaped cross-sectional shape;
The cleaning apparatus, wherein the brushes are arranged radially or spirally with respect to the center of the brush arrangement surface. 2. The cleaning apparatus according to claim 1, wherein said plurality of brush bodies are made of any one of PTFE, PCTFE, PVDF, PVF, PFA, FEP, ETFE and ECTFE. 3. The cleaning apparatus according to claim 1, wherein each of said plurality of brush bodies is a bundle of hollow fibers or a foam. 4. The cleaning apparatus according to claim 1, wherein the cleaning liquid is pure water, SC1 liquid, hydrofluoric acid, or ozone water. 5. The cleaning apparatus according to claim 1, wherein said wafer is a polished silicon wafer. 3. The plurality of brush bodies are arranged such that the cross-sectional shape is horizontally long when the direction of rotation of the rotatable brush head is the vertical direction. The cleaning processing apparatus according to any one of claims 1 to 5.

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