Brush Cleaning Device

Abstract

To provide a brush cleaning device capable of lengthening an exchange period of a cleaning brush by effectively emitting a jet of cleaning fluid to an outer peripheral surface of the cleaning brush and efficiently removing foreign matter remaining on a surface of the cleaning brush.SOLUTION: A brush cleaning device comprises a cleaning brush 15 for cleaning a wafer while rotating, and a nozzle 21 that sprays a cleaning mist 22 linearly in a view from a side face direction, toward an outer peripheral surface of the cleaning brush 15.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a brush cleaning device, and more particularly to a brush cleaning device for cleaning brushes that clean substrates such as semiconductor wafers after processing such as chemical mechanical polishing (CMP). [Background technology]

[0002] On the surface of a wafer processed by chemical mechanical polishing (CMP) or the like, particles from the abrasives used, metal impurities contained in chemicals, ions and fine particles of the metals used in the metal wiring on the wafer, etc. adhere in large quantities. Because these particles have a negative effect on the finished product, such as semiconductor devices, the wafer surface after polishing is usually cleaned using a cleaning brush and cleaning solution (see, for example, Patent Document 1).

[0003] The cleaning device described in Patent Document 1 discloses a technology in which a cleaning liquid is sprayed onto the surface of a rotating wafer and the wafer surface is scrubbed with a rotating brush to remove foreign matter from the wafer surface and protrusions formed in other processes.

[0004] In a technique in which a rotating brush is used to scrub the wafer surface to remove foreign particles and protrusions, the removed foreign particles and protrusions can remain inside the brush and have a negative effect (secondary contamination) on the wafer surface.

[0005] To address this issue, a brush cleaning device is known that sprays a cleaning liquid onto the outer peripheral surface of a rotating brush to remove foreign matter from the brush surface (no patent document).

[0006] Figures 8 and 9 show the main components of a conventional brush cleaning device. The conventional brush cleaning device shown in Figures 8 and 9 sprays cleaning liquid 104 in a straight line from multiple cleaning ports 102 arranged in a line on a pipe material 101 toward the outer circumferential surface of a rotating cleaning brush 103, and removes foreign matter remaining on the brush surface of the cleaning brush 103 with the cleaning liquid 104. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 59-193029 Summary of the Invention [Problem to be solved by the invention]

[0008] In the structure of a conventional brush cleaning device shown in Figures 8 and 9, which removes foreign matter by spraying cleaning liquid 104 linearly onto the brush surface of cleaning brush 103 from multiple cleaning ports 102 arranged in a line on pipe material 101, there was a problem that the cleaning brush 103 deteriorates and becomes contaminated in proportion to the length of use, losing its cleaning effect and making it impossible to sufficiently remove foreign matter, which is a contaminant.

[0009] Therefore, a technical problem arises that must be solved in order to create a structure that can effectively spray cleaning liquid onto the outer surface of the cleaning brush, efficiently remove foreign matter remaining on the surface of the cleaning brush, and extend the replacement cycle of the cleaning brush.The present invention aims to solve this problem. [Means for solving the problem]

[0010] The present invention has been proposed to achieve the above-mentioned object, and the invention described in claim 1 provides a brush cleaning device comprising a cleaning brush that rotates to clean a substrate, and a nozzle that sprays cleaning mist in a straight line, as viewed from the side, toward the outer periphery of the cleaning brush.

[0011] According to this configuration, the nozzle sprays cleaning mist onto the outer circumferential surface of the cleaning brush. Therefore, when cleaning water is converted into cleaning mist and sprayed onto the outer circumferential surface of the cleaning brush, the droplets produced by the cleaning water become very small, and the flow rate and impact force of the droplets increase. Then, by directly hitting the foreign matter in the pores of the cleaning brush with the small droplets with high flow rate and impact force, the foreign matter can be efficiently removed from the pores. In addition, as the droplets of the cleaning mist intermittently collide with foreign matter inside the pores of the cleaning brush, both the cleaning brush and the foreign matter vibrate, loosening the bond and causing the foreign matter to fall to the outside along with the droplets, thereby enabling the foreign matter to be removed efficiently. Furthermore, by spraying the cleaning water in the form of cleaning mist, a film of cleaning water hits a wide area of ​​the cleaning brush, allowing foreign matter to be removed more efficiently.

[0012] A second aspect of the present invention provides the brush cleaning device according to the first aspect, wherein the nozzle sprays the cleaning mist that spreads in a fan shape in plan view.

[0013] According to this configuration, by spraying the cleaning mist in a fan-shaped manner in a plan view, the droplets can be sprayed with the same strength over a wide area of ​​the cleaning brush, and foreign matter caught in the cleaning brush can be removed evenly.

[0014] The invention described in claim 3 provides a brush cleaning device having the configuration described in claim 1 or 2, wherein the nozzle sprays the cleaning mist in a direction tangent to the outer periphery of the cleaning brush when viewed from the side.

[0015] With this configuration, the spray is directed in a direction that contacts the outer periphery of the cleaning brush, so that droplets that hit foreign matter on the cleaning brush fall down along with the foreign matter under the influence of gravity and are efficiently removed together with the foreign matter.

[0016] The invention described in claim 4 provides a brush cleaning device in the configuration described in claim 1, 2 or 3, wherein the nozzle sprays the cleaning mist in a direction that contacts the lower outer periphery of the cleaning brush when viewed from the side.

[0017] With this configuration, the nozzle sprays the cleaning mist in a direction that contacts the lower outer periphery of the cleaning brush, so that droplets that hit foreign matter on the cleaning brush are immediately dropped from the lower outer periphery of the cleaning brush together with the foreign matter by gravity, and are efficiently removed together with the foreign matter.

[0018] The invention as set forth in claim 5 provides a brush cleaning device according to the configuration set forth in claim 1, 2, 3 or 4, further comprising a scraper that scrapes off dust adhering to the outer circumferential surface of the cleaning brush.

[0019] According to this configuration, dust can be efficiently removed by electrically attaching the dust charged by the cleaning mist to the scraper. [Effects of the Invention]

[0020] According to the invention, the nozzle sprays the cleaning mist onto the outer peripheral surface of the cleaning brush, so the droplets of cleaning water sprayed onto the outer peripheral surface of the cleaning brush become small in size and have high flow rate and impact force.These small droplets with high flow rate and impact force directly hit the foreign matter in the pores of the cleaning brush to clean it, so the foreign matter in the pores can be removed efficiently. In addition, the droplets of the cleaning mist intermittently collide with the foreign matter in the pores of the cleaning brush, causing both the cleaning brush and the foreign matter to vibrate and loosen the bond, causing the foreign matter to fall to the outside along with the droplets, thereby enabling the foreign matter to be removed efficiently. Furthermore, by changing the cleaning water into cleaning mist and spraying it, the droplets hit a wide area of ​​the cleaning brush, making it possible to remove foreign matter more efficiently. In this way, foreign matter on the surface of the cleaning brush can be removed efficiently, making it possible to extend the replacement cycle of the brush. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view schematically showing the overall structure of a substrate cleaning device in a semiconductor manufacturing apparatus to which the present invention is applied; [Figure 2] FIG. 2 is a plan perspective view showing the arrangement of main components of a brush cleaning device in the substrate cleaning apparatus. [Figure 3] FIG. 3 is a side view of the arrangement of main components of the brush cleaning device shown in FIG. 2. [Figure 4] 2 is a perspective view showing a main configuration of an upper brush unit in the brush cleaning device of the present invention. FIG. [Figure 5] 5 is a perspective view showing the main configuration of the upper brush unit of the same as viewed from a rear side different from that of FIG. 4. FIG. [Figure 6] 4A and 4B are diagrams showing an example of cleaning mist sprayed from a nozzle in the brush cleaning device, in which FIG. 4A is a diagram showing the cleaning mist as seen from the side, and FIG. 4B is a diagram showing the cleaning mist as seen from above. [Figure 7] FIG. 10 shows the results of checking the brush performance in the case of the structure of the brush cleaning device of the present invention (a), the brush performance in the case of the structure of the brush cleaning device of the present invention (b), and the brush performance in the case of a conventional brush cleaning device (c). [Figure 8] FIG. 10 is a perspective view showing an example of a main configuration of a conventional brush cleaning device. [Figure 9] FIG. 8 is a perspective view showing the main configuration of a conventional brush cleaning device, as viewed from a rear side different from that shown in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0022] To achieve the object of the present invention of providing a brush cleaning device that can effectively spray cleaning liquid onto the outer peripheral surface of a cleaning brush, efficiently remove foreign matter remaining on the surface of the cleaning brush, and extend the replacement cycle of the cleaning brush, the device is configured to include a cleaning brush that rotates to clean substrates, and a nozzle that sprays cleaning mist in a straight line, as viewed from the side, toward the outer periphery of the cleaning brush. [Example]

[0023] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the following embodiment, when the number, value, amount, range, etc. of components is mentioned, the number is not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited to a specific number in principle.

[0024] Furthermore, when referring to the shape or positional relationship of components, etc., it includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or when it is clearly considered otherwise in principle.

[0025] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional proportions of the components may not be the same as in reality. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0026] In the following description, expressions indicating directions such as up, down, left, and right are not absolute, but are appropriate when each part of the wafer polishing apparatus of the present invention is in the posture shown in the drawing, but if the posture changes, they should be interpreted accordingly. Furthermore, the same elements are given the same symbols throughout the description of the embodiments.

[0027] Figure 1 is a perspective view showing a schematic overall structure of a substrate cleaning apparatus 10 to which the present invention is applied. As shown in Figure 1, the substrate cleaning apparatus 10 is installed in a cleaning tank (not shown) of a semiconductor manufacturing apparatus. The substrate cleaning apparatus 10 installed in the cleaning tank includes a plurality of rotation drive rollers 11 that hold a wafer (substrate) W and horizontally rotate the wafer W, an upper brush unit 12A disposed above the rotating wafer W, a lower brush unit 12B disposed below the wafer W, and motors 14A and 14B as drive sources that apply rotational drive forces to the rotation drive rollers 11, the upper brush unit 12A, and the lower brush unit 12B, respectively.

[0028] The upper brush unit 12A has both ends held by the upper unit frame 13A, and the lower brush unit 12B has both ends held by the lower unit frame 13B.

[0029] As shown in FIGS. 1 to 3, the upper brush unit 12A and the lower brush unit 12B are disposed above and below the position where the wafer W is disposed. The upper brush unit 12A and the lower brush unit 12B are movable between a cleaning position where they come into contact with the wafer W and a load / unload position that is vertically spaced apart from the wafer W to enable loading and unloading of the wafer W. When loading and unloading the wafer W, the upper unit frame 13A and the lower unit frame 13B are disposed at the load / unload positions that are vertically spaced apart from each other, enabling loading and unloading of the wafer W. On the other hand, when cleaning the wafer W, the upper brush unit 12A and the lower brush unit 12B are disposed close to each other and at the cleaning position where they come into contact with the upper and lower surfaces of the wafer W.

[0030] The upper brush unit 12A and the lower brush unit 12B are formed to be approximately symmetrical in the vertical direction. The configurations of the upper brush unit 12A and the lower brush unit 12B will be explained using the upper brush unit 12A as a representative, with reference to Figures 1, 2, 3, 4, and 5. Therefore, the configuration of the lower brush unit 12B can be understood by reading it in the vertical direction opposite to the upper brush unit 12A.

[0031] 4 and 5 show the main configuration of the upper brush unit 12A, with Fig. 4 being a perspective view of the upper brush unit 12A seen from diagonally above the front, and Fig. 5 being a perspective view of the upper brush unit 12A seen from diagonally above the rear. As shown in Figs. 4 and 5, the upper brush unit 12A is provided with a cleaning brush 15, a cleaning water supply unit 16, a scraper 17, etc. The cleaning water supply unit 16 and the scraper 17 constitute a brush cleaning device 20 according to the present invention for cleaning the outer peripheral surface of the cleaning brush 15 within the upper brush unit 12A.

[0032] As shown in Fig. 1, both left and right end sides of the cleaning brush 15 are rotatably supported by the upper unit frame 13A (the cleaning brush 15 of the lower brush unit 12B is supported by the lower unit frame 13B) via pivots 18. The cleaning brush 15 rotates by receiving a driving force from a motor 14A also shown in Fig. 1, and is capable of cleaning the surface of the wafer W during this rotation. Almost the entire outer periphery of the cleaning brush 15 is covered with a porous sponge made from PVA (polyvinyl alcohol), and a large number of holes are formed in the surface portion.

[0033] The cleaning water supply unit 16 has both ends supported by the upper unit frame 13A (the cleaning water supply unit 16 of the lower brush unit 12B is supported by the lower unit frame 13B) and is provided with a pivot 18 arranged parallel to the cleaning brush 15, a cleaning water supply pipe 19 attached to the upper unit frame 13A (or the lower unit frame 13B), and two nozzles 21 connected to the cleaning water supply pipe 19 and arranged parallel to and spaced apart from the cleaning brush 15.

[0034] Washing water is supplied to the washing water supply pipe 19, and the nozzle 21 changes the washing water supplied into the washing water supply pipe 19 into atomized washing mist 22 and sprays it toward the peripheral surface of the washing brush 15.

[0035] 6, the cleaning mist 22 sprayed from the nozzle 21 appears linear in side view as shown in (a) and fan-shaped in plan view as shown in (b), and appears to be spread out in a substantially horizontal direction (the longitudinal direction of the cleaning brush 15). The direction of the spray is set so that the cleaning mist 22 is sprayed in the tangent direction to the outer periphery of the cleaning brush 15 and in the tangent direction to the lower part of the outer periphery when viewed from the side (one end side of the cleaning brush 15).

[0036] The scraper 17 is a brush or spatula made of an elastic material that scrapes off foreign matter remaining on the outer peripheral surface of the cleaning brush 15. The scraper 17 has both left and right ends fixed to the upper unit frame 13A (the scraper 17 of the lower brush unit 12B is fixed to the lower unit frame 13B), is parallel to the cleaning brush 15, and its tongue-shaped tip elastically deforms and slides against the outer peripheral surface of the rotating cleaning brush 15 to scrape off the foreign matter.

[0037] Next, we will explain an example of the operation of the thus configured substrate cleaning apparatus 10. First, with the upper brush unit 12A and the lower brush unit 12B in the retracted position, vertically spaced apart from each other, and with the rotation of the rotation drive rollers 11 stopped, a wafer W is transported by a transport means (not shown) to a cleaning position surrounded by the plurality of rotation drive rollers 11 and set thereon.

[0038] Next, motors 14A and 14B are driven, and the driving forces of motors 14A and 14B rotate the rotation drive roller 11 and the cleaning brushes 15 of the upper brush unit 12A and the cleaning brushes 15 of the lower brush unit 12B, respectively. Note that the cleaning brushes 15 of the upper brush unit 12A and the cleaning brushes 15 of the lower brush unit 12B rotate in opposite directions. Also, cleaning nozzles (not shown) supply cleaning liquid to the top and bottom surfaces of the wafer W, respectively.

[0039] Furthermore, the upper brush unit 12A and the lower brush unit 12B are placed in the cleaning position, and the cleaning brushes 15 of the upper brush unit 12A and the cleaning brushes 15 of the lower brush unit 12B are pressed against the front and back surfaces of the opposing wafer W with the required pressure while rotating.

[0040] In this way, the cleaning brushes 15 of the upper brush unit 12A and the cleaning brushes 15 of the lower brush unit 12B, which rotate in opposite directions, are pressed against the front and back surfaces of the wafer W with the required pressure, thereby cleaning both the front and back surfaces of the wafer W.

[0041] When the required cleaning process for the wafer W is completed, the rotation of the upper brush unit 12A and the lower brush unit 12B is stopped and they are moved from the cleaning position to the carry-in / carry-out position. In addition, the rotation drive roller 11 is stopped, and the wafer W is discharged by the transport means and transported to the next process.

[0042] The above is the action of cleaning the wafer W. During the cleaning process of the wafer W, foreign matter or protrusions generated in other processes may remain on the surface of the cleaning brush 15, and it is necessary to clean and remove the foreign matter from the surface of the cleaning brush 15. This removal process may be performed after each cleaning process of a wafer W or after each cleaning process of multiple wafers W.

[0043] When cleaning the cleaning brushes 15, after the wafer W has been transported and removed, the cleaning brushes 15 of the upper brush unit 12A and the cleaning brushes 15 of the lower brush unit 12B are rotated by the driving force of the motor 14A at the retracted position, and cleaning water is supplied to the cleaning water supply pipe 19, and cleaning mist 22 is sprayed from each nozzle 21 toward the circumferential surface of the corresponding cleaning brush 15, cleaning the circumferential surface of the cleaning brush 15 with the sprayed cleaning mist 22.

[0044] Therefore, in the brush cleaning device 20 of this embodiment, the cleaning water is converted into a mist of cleaning mist 22 by the nozzle 21, and this cleaning mist 22 is sprayed onto the outer circumferential surface of the cleaning brush 15. When the cleaning water is sprayed as a mist of cleaning mist 22 onto the outer circumferential surface of the cleaning brush 15 in this way, the droplets of the cleaning water become smaller and the flow rate and impact force of the droplets increase. Then, the droplets (cleaning mist 22) that are smaller in shape and have a higher flow rate and impact force directly hit the foreign matter in the pores of the cleaning brush 15 to clean it, so the foreign matter in the pores can be efficiently removed.

[0045] In addition, the splashes of the cleaning mist 22 intermittently collide with the foreign matter in the pores of the cleaning brush 15, causing both the cleaning brush 15 and the foreign matter to vibrate and loosen the bond, causing the foreign matter to fall to the outside together with the splashes, thereby enabling the foreign matter to be removed efficiently.

[0046] Furthermore, by changing the cleaning water into cleaning mist 22 and spraying it, the droplets of cleaning water hit the cleaning brush 15 over a wide range, so that foreign matter can be removed more efficiently.

[0047] Furthermore, by spraying the cleaning water from the nozzle 21 as a cleaning mist 22 that spreads in a fan shape in plan view, the droplets can be sprayed with the same strength over a wide range of the cleaning brush 15, and foreign matter taken into the cleaning brush can be removed evenly.

[0048] Moreover, since the cleaning mist 22 is sprayed from the nozzle 21 in a direction tangent to the outer periphery of the cleaning brush 15 when viewed from the side, droplets that hit foreign matter on the cleaning brush 15 fall by gravity together with the foreign matter, and the foreign matter is removed efficiently. Moreover, since the cleaning mist 22 is sprayed in a direction tangent to the lower outer periphery of the cleaning brush 15 when viewed from the side, droplets that hit foreign matter on the cleaning brush 15 fall by gravity immediately from the lower end of the outer periphery of the cleaning brush 15 together with the foreign matter, and are removed even more efficiently together with the foreign matter.

[0049] Furthermore, a scraper 17 is provided to scrape off dust adhering to the outer peripheral surface of the cleaning brush 15, so that the dust charged by the cleaning mist 22 can be electrically attached to the scraper 17 and efficiently removed.

[0050] 7 shows the results of an experiment verifying the effects of the brush cleaning device 20 according to the present invention. In this verification, a comparison was made between a case in which cleaning water (cleaning liquid) was sprayed onto the cleaning brush only while one workpiece was cleaned, a case in which cleaning water (cleaning liquid) was sprayed onto the cleaning brush while ten workpieces were cleaned, and a case in which cleaning water (cleaning liquid) was sprayed onto the cleaning brush while twenty workpieces were cleaned.

[0051] In the case of the present invention shown in (a) in Figure 7, in which cleaning water is converted into cleaning mist and sprayed, and a scraper is used, the amount of dust remaining after the first pass was 732, after the 10th pass was 26, and after the 20th pass was 7.

[0052] When cleaning water was replaced with cleaning mist and sprayed as in the present invention shown in (b) of Figure 7, the amount of dust remaining after the first spray was 15,557 particles, after the 10th spray was 39 particles, and after the 20th spray was 32 particles.

[0053] In contrast, in the case of the conventional structure shown in (c) of Figure 7, in which cleaning water is sprayed directly onto the cleaning brush and a scraper is used, the amount of dust remaining after the first pass was 2,896 particles, after the 10th pass was 286 particles, and after the 20th pass was 106 particles.

[0054] Therefore, it was found that the structure (a) of the present invention significantly reduced the amount of dust residue compared to the conventional structure (c) when cleaning 1, 10, or 20 sheets, and improved brush cleaning performance.

[0055] Furthermore, in the structure of the present invention (b), in which the cleaning water is mist sprayed, no significant effect is seen when cleaning one sheet, but when cleaning 10 and 20 sheets, the amount of remaining dust is drastically reduced compared to the conventional structure (c). It was confirmed that mist spray has a significant effect when cleaning is repeated.

[0056] The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention also covers such modifications. [Explanation of symbols]

[0057] 10: Substrate cleaning equipment 11: Rotation drive roller 12A: Upper brush unit 12B: Lower brush unit 13A: Upper unit frame 13B: Lower unit frame 14A: Motor 14B: Motor 15: Cleaning brush 16: Cleaning water supply unit 17: Scraper 18: Axis 19: Cleaning water supply pipe 20: Brush cleaning device 21: Nozzle 22: Cleaning mist W: Wafer

Claims

1. a cleaning brush that rotates to clean the substrate; a nozzle that sprays cleaning mist linearly toward the outer periphery of the cleaning brush when viewed from the side; A brush cleaning device comprising:

2. 2. The brush cleaning device according to claim 1, wherein the nozzle sprays the cleaning mist in a fan shape when viewed from above.

3. 3. The brush cleaning device according to claim 1, wherein the nozzle sprays the cleaning mist in a direction tangent to an outer periphery of the cleaning brush when viewed from the side.

4. 3. The brush cleaning device according to claim 1, wherein the nozzle sprays the cleaning mist in a direction that contacts a lower outer periphery of the cleaning brush when viewed from the side.

5. 5. The brush cleaning device according to claim 1, further comprising a scraper for scraping off dust adhering to the outer peripheral surface of the cleaning brush.

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