JP2010099637A - Apparatus and method for cleaning substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for cleaning a substrate, in each of which dust or the like stuck to the surface of the substrate can be removed efficiently and the removed dust is prevented from being stuck again to the surface of the substrate after the substrate is cleaned. <P>SOLUTION: The substrate W is cleaned by immersing a substrate W-held holder 50 in a cleaning liquid L in an immersion tank 2 while making the cleaning liquid L flow horizontally in a laminar flow state in the immersion tank 2. In other words, the substrate W is cleaned by arranging the holder 50 in the immersion tank 2 so that the main surface of the substrate W becomes parallel to the flow direction of the cleaning liquid L while forcing a part of the cleaning liquid L flowing on the upstream side of the holder 50 to form a turbulent flow. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a substrate cleaning apparatus and a substrate cleaning method for cleaning a substrate such as a magnetic recording medium substrate.

  For example, as a substrate for a magnetic recording medium used for a hard disk drive or the like, a disk-shaped aluminum substrate or a glass substrate having a central hole is used. Since such a magnetic recording medium substrate is manufactured through various surface treatment processes such as polishing on the surface, a substrate cleaning process for removing dust and the like adhering to the surface of the substrate after the surface treatment process and the like. Has been done.

  In addition, with the demand for higher recording density of magnetic recording media, high flatness of magnetic recording media is required, while advanced cleaning technology for removing dust and the like adhering to the surface of the substrate is required. It has been.

  In cleaning such a magnetic recording medium substrate, a cleaning liquid is supplied from the bottom of the immersion tank, and the holder holding the substrate is immersed in the cleaning liquid in the immersion tank while overflowing the cleaning liquid from the top of the immersion tank. In general, a substrate cleaning apparatus that cleans a substrate is used in the field of precision cleaning (see, for example, Patent Document 1).

  However, in the substrate cleaning apparatus that flows the cleaning liquid from the bottom to the top of the immersion tank, the dust, including dust that has peeled off the surface of the substrate, is not discharged from the upper part of the immersion tank together with the cleaning liquid, but a part of the dust stays in the immersion tank. In some cases, stagnation of the cleaning liquid may occur in the immersion bath. In this case, when the holder is pulled up from the immersion tank, dust staying in the cleaning liquid may reattach to the surface of the substrate.

  On the other hand, there has been proposed a substrate cleaning apparatus for cleaning a substrate by immersing a holder holding a substrate in the cleaning liquid in the immersion tank while flowing the cleaning liquid in a laminar flow in a horizontal direction in the immersion tank. (See, for example, Patent Document 2).

  In such a substrate cleaning apparatus that allows the cleaning liquid to flow in the horizontal direction in a laminar state, the cleaning liquid containing dust can be quickly discharged out of the immersion tank, so that the dust reattaches to the surface of the substrate. Can be prevented.

However, when using a substrate cleaning apparatus that flows the cleaning liquid in a laminar flow state to clean a flat object to be cleaned such as a magnetic recording medium substrate, the cleaning liquid hits the surface of the substrate too smoothly, There is a disadvantage that the cleaning ability is lowered.
JP 2008-135109 A JP 11-76956 A

  Therefore, the present invention has been proposed in view of such conventional circumstances, and efficiently removes dust and the like adhering to the surface of the substrate and reattaches them to the surface of the substrate after cleaning. An object of the present invention is to provide a substrate cleaning apparatus and a substrate cleaning method which are prevented.

The present invention provides the following means.
(1) an immersion tank in which a holder holding a substrate is immersed in a cleaning solution;
A laminar flow generating mechanism for flowing a cleaning solution in a laminar flow in the horizontal direction in the immersion tank;
A turbulent flow generating mechanism for generating turbulent flow in a part of the cleaning liquid flowing in the laminar flow state,
The holder is disposed in the immersion tank so that the main surface of the substrate is parallel to the direction in which the cleaning liquid flows, and the turbulent flow generation mechanism is disposed upstream of the holder. Substrate cleaning device.
(2) The substrate cleaning apparatus according to (1), wherein the turbulent flow generation mechanism includes a pole that is reciprocated while being immersed in the cleaning liquid in the immersion tank.
(3) The substrate cleaning apparatus according to (2), wherein the pole is reciprocated at least in a direction crossing a direction in which the cleaning liquid flows.
(4) The substrate cleaning apparatus according to (2) or (3), wherein a plurality of the poles are arranged side by side in a direction intersecting with a direction in which the cleaning liquid flows and are operated in synchronization with each other. .
(5) The substrate cleaning apparatus according to any one of claims 1 to 4, wherein a plurality of the substrates are held side by side in the holder in parallel with each other.
(6) The substrate cleaning apparatus according to any one of (1) to (5), wherein the substrate is a substrate for a magnetic recording medium.
(7) A substrate cleaning method for cleaning the substrate by immersing a holder holding the substrate in the cleaning liquid in the immersion tank while flowing the cleaning liquid horizontally in a laminar flow in the immersion tank. ,
The substrate is disposed in the immersion tank so that the main surface of the substrate is parallel to the flow direction of the cleaning liquid, and turbulence is generated in a part of the cleaning liquid flowing upstream from the holder, while the substrate is A method for cleaning a substrate, comprising:
(8) The substrate cleaning method according to (7), wherein a turbulent flow is generated in a part of the cleaning liquid by reciprocating a pole immersed in the cleaning liquid in the immersion tank.
(9) The substrate cleaning method according to (8), wherein the pole is reciprocated at least in a direction intersecting with a direction in which the cleaning liquid flows.
(10) The substrate cleaning method according to (8) or (9) above, wherein a plurality of the poles are arranged side by side in a direction intersecting with the direction in which the cleaning liquid flows, and are operated in synchronization with each other.
(11) The substrate cleaning method according to any one of (7) to (10) above, wherein cleaning is performed on a plurality of substrates held side by side in parallel with the holder.
(12) The substrate cleaning method according to any one of (7) to (11), wherein a magnetic recording medium substrate is cleaned as the substrate.

  As described above, according to the present invention, it is possible to efficiently remove dust and the like adhering to the surface of the substrate, and to perform advanced substrate cleaning that prevents them from reattaching to the surface of the substrate after cleaning. It is.

  Hereinafter, a substrate cleaning apparatus and a substrate cleaning method to which the present invention is applied will be described in detail with reference to the drawings. In the drawings used in the following description, in order to make the features easy to understand, the portions that become the features may be schematically shown for convenience, and the dimensional ratios of the portions are not always the same as the actual ones.

  In the present embodiment, for example, a case where a substrate W for a magnetic recording medium mounted on a hard disk drive is cleaned using a substrate cleaning apparatus 1 to which the present invention is applied as shown in FIGS. explain.

  In addition, as the cleaning liquid L for cleaning the substrate W, pure water is basically used, but other than that, treated water subjected to chemical treatment or the like can be used. Can be appropriately selected and used according to the substrate W to be cleaned.

  As shown in FIGS. 1 and 2, the substrate cleaning apparatus 1 to which the present invention is applied includes an immersion tank 2 in which a holder 50 holding a substrate W is immersed in the cleaning liquid L, and a laminar flow of the cleaning liquid L in the immersion tank 2. A laminar flow generating mechanism 3 that flows horizontally in a state, and a turbulent flow generating mechanism 4 that generates turbulent flow in a part of the cleaning liquid L that flows in a laminar state.

  The holder 50 holds a plurality of disk-shaped substrates W formed with a center hole in parallel with each other. In addition, each substrate W is supported by a pair of support plates 51 a and 51 b provided on the holder 50 at outer peripheral portions on both sides across a vertical center line passing through the center hole. The pair of support plates 51a and 51b are provided with V-shaped grooves (not shown) with which the outer peripheral portions of the respective substrates W are engaged.

  Each substrate W is supported by the pair of support plates 51a and 51b, and is held by the holder 50 in a vertically placed state (a state where the main surface of the substrate W is parallel to the vertical direction). And this holder 50 is arrange | positioned on the bottom face of the immersion tank 2 so that the main surface of each board | substrate W may become parallel to the direction through which the washing | cleaning liquid L flows. In this example, about 50 substrates W having a diameter of 2.5 inches are arranged in a row at intervals of about 5 mm and held in the holder 50.

  The immersion tank 2 has a rectangular bottom wall 2a, four side walls 2b, 2c, 2d, and 2e that rise from the periphery of the bottom wall 2a, and an opening 2f on the upper surface that faces the bottom wall 2a. Is formed in a substantially rectangular parallelepiped shape. The bottom wall 2a of the immersion tank 2 is provided with a supply port 5a for supplying the cleaning liquid L and a discharge port 5b for discharging the cleaning liquid L. Among these, a plurality of supply ports 5a are provided side by side along the vicinity of the upstream side wall 2b in the longitudinal direction in which the cleaning liquid L flows. On the other hand, a plurality of discharge ports 5b are provided side by side along the vicinity of the side wall 2d on the downstream side in the longitudinal direction in which the cleaning liquid L flows.

  Further, on the upstream side of the immersion tank 2, a laminar flow generating mechanism 3 described later includes a storage space S1 in which the cleaning liquid L supplied from the supply port 5a is stored, and an immersion space S2 in which the holder 50 is immersed. It is provided so as to partition the space. On the other hand, on the downstream side of the immersion tank 2, a partition wall 6 is provided that partitions the immersion space S2 and the discharge space S3 from which the cleaning liquid L is discharged from the discharge port 5b. The partition wall 6 is provided with a plurality of through holes 6a through which the cleaning liquid L that has cleaned the substrate W passes. The height of the partition wall 6 is set lower than the four side walls 2b, 2c, 2d, and 2e so that a part of the cleaning liquid L overflows from the upper part.

  The laminar flow generating mechanism 3 rectifies the flow of the cleaning liquid L flowing from the storage space S1 toward the immersion space S2 using a buffer material having water flow resistance such as a porous plate or a nonwoven fabric, for example, and the immersion space S2 This is for flowing the cleaning liquid L in the horizontal direction in a laminar flow state.

  In addition, a laminar flow means the state in which the flow line of a flow flows orderly. In this example, the laminar flow cleaning liquid L is flowed in the horizontal direction at a constant flow rate (for example, about 10 mm / sec). The configuration of the laminar flow generating mechanism 3 is not particularly limited as long as the cleaning liquid L can flow in the horizontal direction in a laminar flow state, and can be appropriately changed and implemented. is there.

  The turbulent flow generation mechanism 4 has a plurality of poles 7 that are reciprocated in a direction crossing the direction in which the cleaning liquid L flows while being immersed in the cleaning liquid L in the immersion space S2. Specifically, a plurality of poles 7 are arranged in the immersion space S <b> 2 upstream of the holder 50 in a direction perpendicular to the direction in which the cleaning liquid L flows at regular intervals.

  The plurality of poles 7 are connected to a drive mechanism (not shown), and are reciprocated (vibrated) with a constant stroke in a direction orthogonal to the direction in which the cleaning liquid L flows while being synchronized with each other by the drive of the drive mechanism. Is done. Thereby, in the turbulent flow generation mechanism 4, turbulent flow can be generated in a part of the cleaning liquid L that flows in a laminar flow in the immersion space S2. The turbulent flow refers to a state in which the flow line of the flow is disturbed and flows while mixing.

  In this example, the thickness of the pole 7 is about 2 to 3 mm, and one pole 7 is arranged for one substrate W, and the stroke of each pole 7 is about 10 mm, and each pole 7 is Although the reciprocating operation is performed with a period of about 0.5 seconds, when the stroke of the pole 7 is increased, a configuration in which one pole 7 is arranged for two to three substrates W is also possible. .

  In the substrate cleaning apparatus 1, since the cleaning liquid L flowing in the immersion tank 2 is reused cyclically, the cleaning liquid L discharged from the discharge port 5 b is stored in the reservoir tank 8 and the reservoir tank 8. A pump 9 for pumping the cleaning liquid L to the supply port 5a and a filter 10 for purifying the cleaning liquid L pumped by the pump 9 are provided.

  In the substrate cleaning method to which the present invention is applied, the plurality of substrates W held by the holder 50 are cleaned using the substrate cleaning apparatus 1 having the above structure. Specifically, in the substrate cleaning method using the substrate cleaning apparatus 1, a plurality of cleaning liquids L in the immersion space S <b> 2 are supplied to the cleaning liquid L in the immersion space S <b> 2 while flowing the cleaning liquid L in the laminar flow in the horizontal direction. The holder 50 holding the substrate W is immersed.

  At this time, in the immersion tank 2, the main surface of each substrate W held by the holder 50 is parallel to the flowing direction of the cleaning liquid L, and the laminar cleaning liquid L flows between the substrates W. Become. Furthermore, in this immersion tank 2, turbulent cleaning liquid L flows between the substrates W by generating turbulent flow in a part of the cleaning liquid L flowing upstream from the holder 50. Accordingly, in the present invention, dust such as dust attached to the surface of each substrate W can be efficiently removed as compared with the case where only the laminar cleaning liquid L flows between the substrates W.

  Further, in the substrate cleaning apparatus 1, the cleaning liquid L containing dust can be quickly discharged out of the immersion tank 2 by flowing the cleaning liquid L in the horizontal direction. Therefore, in the present invention, dust can be prevented from reattaching to the surface of the substrate W when the holder 50 is pulled up from the immersion bath 2.

  As described above, according to the present invention, it is possible to efficiently remove dust and the like adhering to the surface of the substrate, and to perform advanced substrate cleaning that prevents them from reattaching to the surface of the substrate after cleaning. It is.

  In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

  For example, the turbulent flow generation mechanism 4 is configured to move the pole 7 in a direction crossing the direction in which the cleaning liquid L flows in order to generate turbulent flow in a part of the cleaning liquid L that flows in a laminar state. However, in addition to this operation direction, for example, the pole 7 can be reciprocated in the direction in which the cleaning liquid L flows, or the pole 7 can be reciprocated in the vertical direction (axial direction). Further, these operations can be combined.

  Further, the shape, number, arrangement, and the like of the pole 7 can be appropriately changed according to the substrate W to be cleaned.

  Furthermore, in the present invention, in order to enhance the cleaning ability for the substrate W, it is also possible to apply ultrasonic vibration (for example, about 500 W at 200 kHz) to the cleaning liquid L in the immersion space S2.

  Further, the holder 50 is configured to support the outer peripheral portion of each substrate W at two points by the pair of support plates 51a and 51b. However, the configuration is not limited to this configuration, and the outer peripheral portion supporting each substrate W. The position, the number of points, and the like can be appropriately changed and implemented. For example, the outer peripheral portion of each substrate W can be supported at three points or supported at four points.

  Further, the members that support the outer peripheral portion of each substrate W are not limited to the support plates 51a and 51b as long as they do not disturb the flow of the cleaning liquid L flowing in the immersion bath 2. The shape and the like can be changed as appropriate.

  Further, the present invention provides a lubricant for the magnetic recording medium substrate W described above, for example, after forming a magnetic film or the like separately from the step of removing dust and the like adhering to the surface after the surface treatment step or the like. The present invention can also be applied to cleaning of a magnetic recording medium before coating. Furthermore, the present invention is not limited to the case of cleaning the above-described magnetic recording medium substrate W, but can be suitably used for cleaning a flat object to be cleaned.

  Hereinafter, the effects of the present invention will be made clearer by examples. In addition, this invention is not limited to a following example, In the range which does not change the summary, it can change suitably and can implement.

Example 1
In Example 1, the substrate W was actually cleaned using the substrate cleaning apparatus 1 shown in FIGS. The immersion tank 2 has a length of about 300 mm, a depth of about 200 mm, and a height of about 200 mm. Pure water was used as the cleaning liquid L, and the laminar flow rate of the cleaning liquid L was 5 cm / second. The substrate W is a disk-shaped glass substrate having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.8 mm. On the holder 50, 25 substrates W were arranged in parallel at intervals of 7 mm. Then, the holder 50 was immersed in the vicinity of the center in the immersion laminate 2 and arranged so that the main surface of each substrate W was parallel to the direction in which each cleaning liquid L flows. At a position 20 mm away from the holder 50 in the immersion layer 2, 25 poles 7 having a thickness of 3 mm were arranged side by side at intervals of 7 mm in a direction orthogonal to the direction in which the cleaning liquid L flows. During cleaning, these poles 7 were reciprocated at a cycle of 1 second while moving within a range of ± 5 mm in a direction orthogonal to the direction in which the cleaning liquid L flows. During the cleaning, ultrasonic vibration of 200 kHz and 500 W was applied to the cleaning liquid L from the bottom of the immersion tank 2. The cleaning time was 2 minutes, and after cleaning, the substrate W was spin-dried. Such cleaning was performed on 1000 substrates W.

  And about each board | substrate W of Example 1, the dust which remains on the surface was investigated using the laser light scattering type surface inspection machine. As a result, no dust was detected from the 1000 washed substrates W.

(Comparative Example 1)
In Comparative Example 1, 1000 substrates W were cleaned in the same manner as in Example 1 except that the pole 7 that generates turbulent flow in the immersion tank 2 was not provided. Then, when the dust remaining on the surface of each substrate W in Comparative Example 1 was examined, dust having a size of about 1 to 5 μm was detected from five of the 1000 substrates W that were cleaned. It was.

  As described above, according to the present invention, it is possible to efficiently remove dust and the like adhering to the surface of the substrate, and to perform advanced substrate cleaning that prevents them from reattaching to the surface of the substrate after cleaning. It is.

FIG. 1 is a cross-sectional view showing a configuration of a substrate cleaning apparatus to which the present invention is applied. FIG. 2 is a plan view showing the configuration of the substrate cleaning apparatus to which the present invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Substrate cleaning apparatus 2 ... Immersion tank 3 ... Laminar flow generation mechanism 4 ... Turbulence generation mechanism 5a ... Supply port 5b ... Discharge port 6 ... Partition wall 6a ... Through-hole 7 ... Pole 8 ... Reservoir tank 9 ... Pump 10 ... Filter 50 ... Holder W ... Substrate L ... Cleaning liquid

Claims (12)

An immersion tank for immersing the holder holding the substrate in the cleaning liquid;
A laminar flow generating mechanism for flowing a cleaning solution in a laminar flow in the horizontal direction in the immersion tank;
A turbulent flow generating mechanism for generating turbulent flow in a part of the cleaning liquid flowing in the laminar flow state,
The holder is disposed in the immersion tank so that the main surface of the substrate is parallel to the direction in which the cleaning liquid flows, and the turbulent flow generation mechanism is disposed upstream of the holder. Substrate cleaning device.   The substrate cleaning apparatus according to claim 1, wherein the turbulent flow generation mechanism includes a pole that is reciprocated while being immersed in a cleaning liquid in the immersion tank.   The substrate cleaning apparatus according to claim 2, wherein the pole is reciprocated at least in a direction intersecting a direction in which the cleaning liquid flows.   4. The substrate cleaning apparatus according to claim 2, wherein a plurality of the poles are arranged side by side in a direction intersecting with a direction in which the cleaning liquid flows, and are operated in synchronization with each other.   5. The substrate cleaning apparatus according to claim 1, wherein a plurality of the substrates are held in parallel in the holder in a state parallel to each other.   The substrate cleaning apparatus according to claim 1, wherein the substrate is a magnetic recording medium substrate. A substrate cleaning method for cleaning the substrate by immersing a holder holding the substrate in the cleaning liquid in the immersion tank while flowing the cleaning liquid horizontally in a laminar flow state in the immersion tank,
The substrate is disposed in the immersion tank so that the main surface of the substrate is parallel to the flow direction of the cleaning liquid, and turbulence is generated in a part of the cleaning liquid flowing upstream from the holder, while the substrate is A method for cleaning a substrate, comprising:   The substrate cleaning method according to claim 7, wherein a turbulent flow is generated in a part of the cleaning liquid by reciprocating a pole immersed in the cleaning liquid in the immersion tank.   The substrate cleaning method according to claim 8, wherein the pole is reciprocated at least in a direction intersecting a direction in which the cleaning liquid flows.   10. The substrate cleaning method according to claim 8, wherein a plurality of the poles are arranged side by side in a direction crossing a direction in which the cleaning liquid flows, and are operated in synchronization with each other.   The substrate cleaning method according to claim 7, wherein cleaning is performed on a plurality of substrates held side by side in parallel to the holder.   The substrate cleaning method according to claim 7, wherein a substrate for a magnetic recording medium is cleaned as the substrate.

Images