JP2014110270A - Cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable scrub cleaning to be performed on a cleaned surface of a wafer in a spinner table and prevent rear surface contamination caused by contaminants coming around to a rear surface of the wafer.SOLUTION: An outer periphery holding means 20 comprises: a liquid reservoir part 21 which stores a liquid on an upper surface 21a and forms a liquid layer 6; a liquid supply port 22 which supplies the liquid to the upper surface 21a of the liquid reservoir part 21; and a lifting part 23 which selectively positions the liquid reservoir part 21 between an action position P1 and a non action position P2. Thus, when the wafer W is cleaned, the liquid reservoir part 21 is positioned at the action position P1, and an upper surface 7 of the liquid layer 6 formed at the liquid reservoir part 21 is located at a level equivalent to an upper surface 3 of the spinner table 2. Then, the liquid layer 6 holds an outer peripheral part Wc of the wafer W, and a surface Wa of the wafer W is cleaned by cleaning means 10. Further, a rear surface Wb of the wafer W is sealed by the liquid layer 6. The structure prevents contaminants from coming around to the rear surface Wb and reduces rear surface contamination of the wafer W.

Description

  The present invention relates to a cleaning apparatus for cleaning a surface of a wafer.

  Grinding debris (contamination) on the wafer when grinding both sides of the wafer cut from the ingot and the wafer with waviness on both sides and the back side of the wafer that is partitioned by the street and formed with multiple devices on the surface. Because of adhesion, it is necessary to clean the wafer after grinding. In addition, even when the wafer is divided into individual devices by separating the streets with a laser processing device or a dicing device after the back surface of the wafer on which the device is formed, cutting waste or the like (contamination) adheres to the wafer. Therefore, it is necessary to clean the wafer after dividing.

  In general grinding equipment and dicing equipment, a processing means for grinding or cutting a wafer held on a chuck table and a spin-type cleaning in which a wafer contaminated by grinding or cutting is cleaned with cleaning water while rotating. At least an apparatus and a transfer apparatus for transferring a wafer are provided. Such a cleaning apparatus has a spinner table that holds and rotates a wafer.

  When cleaning the ground or divided wafer by the cleaning device, the cleaning device transports the cleaning water to the wafer while rotating the spinner table in a state where the wafer is transferred to the spinner table by the transfer device and positioned at the work position. Grinding debris, cutting debris, and the like are removed by supplying to the surface (surface to be cleaned) (see, for example, Patent Document 1 below).

  Further, in order to hold the wafer by the transfer pad from the back side held by the spinner table, the spinner table is often formed smaller than the outer diameter of the wafer. In such a spinner table, since only the center portion of the wafer is held on the spinner table, for example, in Patent Document 2 below, holding of a wafer in which the center portion is held on the spinner table and the outer peripheral portion is not held. There has been proposed a cleaning apparatus provided with brush means for supporting an outer peripheral portion which is not formed. In this cleaning apparatus, the surface of the wafer can be cleaned in a state where the entire back surface of the wafer is supported.

JP 2004-322168 A JP 2000-260740 A

  However, in a cleaning device configured to support the outer periphery of the wafer with a brush, contamination on the wafer surface wraps around the back side of the wafer, and the force applied by the brush in contact with the back surface also adds contamination to the wafer. It may adhere to the outer periphery of the back surface and cannot be removed. Therefore, processing of the wafer is continued without removing the contamination, and the contamination adhered to the outer periphery of the back surface of the wafer cannot be removed even in another cleaning process, resulting in a problem that adversely affects the quality of the device. .

  The present invention has been made in view of the above circumstances, and even with a spinner table having an outer diameter smaller than the size of the wafer, the surface of the wafer can be contacted (scrubbed) and cleaned. There is a problem to be solved by the present invention to prevent back surface contamination caused by contamination around the back surface.

  The present invention provides a spinner table that is formed with a diameter smaller than the outer diameter of the wafer and that can rotate at a high speed while holding the wafer on the upper surface, and supplying cleaning water to the surface to be cleaned held on the upper surface of the spinner table. Cleaning means for cleaning the surface to be cleaned of the wafer, and outer periphery holding means formed by surrounding the spinner table and supporting the outer peripheral portion of the wafer by a liquid layer. A liquid storage section that stores and forms a liquid layer, a liquid supply port that supplies liquid to the upper surface of the liquid storage section, and an elevating section that selectively positions the liquid storage section at an operating position and a non-operating position. The upper surface of the liquid layer formed in the liquid storage portion is positioned at a height position equivalent to the upper surface of the spinner table, and the upper surface of the liquid storage portion is the upper surface of the spinner table in the non-operation position. The liquid storage unit is positioned below the upper surface of the inner table, and at the time of wafer cleaning, the liquid storage unit is positioned at the working position, and liquid is supplied from the liquid supply port to the upper surface of the liquid storage unit. The outer peripheral portion of the wafer held on the upper surface of the wafer is held by the liquid layer formed in the liquid storage portion, and the wafer is rotated by the rotation of the spinner table, and the cleaning surface of the wafer is cleaned by the cleaning means. In the cleaning of the wafer, the liquid storage portion is positioned at the non-operating position, and the surface to be cleaned of the wafer is dried by rotating the spinner table at a high speed. .

The cleaning device according to the present invention includes an outer periphery holding unit that surrounds the spinner table, and the outer periphery holding unit supplies a liquid to the upper surface of the liquid storing unit that stores the liquid on the upper surface and forms a liquid layer. A liquid supply port and an elevating part that selectively positions the liquid storage part at the action position and the non-action position, and when the wafer is cleaned, the liquid storage part is positioned at the action position. Since the upper surface of the liquid layer formed in the liquid storage portion is at the same height as the upper surface of the spinner table and can hold the outer periphery of the wafer, the surface of the wafer can be cleaned by the cleaning means in that state. .
Further, since the liquid layer holds the outer peripheral portion of the wafer, the back surface on the outer peripheral portion side of the wafer is sealed by the liquid layer, so that contamination on the front surface of the wafer can be prevented from entering the back surface. Therefore, the backside contamination of the wafer can be reduced, and adverse effects on device quality can be suppressed.

It is a perspective view which shows the structure of a washing | cleaning apparatus. It is sectional drawing which shows the structure of a spinner table and an outer periphery holding means. It is a perspective view which shows an example of the grinding device carrying a washing | cleaning apparatus. It is sectional drawing which shows a washing | cleaning process. It is sectional drawing which shows a drying process.

  With reference to FIGS. 1 and 2, the configuration of the cleaning apparatus 1 for cleaning the wafer W, which is a workpiece, will be described. The cleaning apparatus 1 holds a workpiece and can rotate at a high speed, a cleaning means 10 for cleaning the workpiece, and a peripheral portion of the workpiece formed around the spinner table 2. Outer peripheral holding means 20 and is configured to be accommodated in a space formed in the central portion of the container 8.

  As shown in FIGS. 1 and 2, the spinner table 2 is formed with a smaller diameter than the outer diameter of the workpiece. The spinner table 2 has a porous member 4, and the surface side thereof is an upper surface 3 for sucking and holding a workpiece. A rotating shaft 5 that rotates the spinner table 2 at a high speed is connected to the lower end of the spinner table 2. The spinner table 2 is configured to be movable up and down in the Z-axis direction, and is movable between the workpiece conveyance area 9a and the cleaning area 9b.

  The cleaning means 10 includes a scrub cleaning member 11 (see FIG. 4) for cleaning (scrubbing) the workpiece. The scrub cleaning member 11 is supported above the spinner table 2 by a support column 12 so as to be rotatable about a horizontal rotation axis. As the scrub cleaning member 11, for example, a sponge can be used, but it is not particularly limited.

  The cleaning means 10 includes a cleaning water supply nozzle 13 for supplying cleaning water to the workpiece held on the spinner table 2 during wafer cleaning, and a workpiece held on the spinner table 2 during wafer drying. And a compressed air supply nozzle 15 for supplying compressed air. The cleaning water supply nozzle 13 and the compressed air supply nozzle 15 are connected to a support portion 17 that rotates the upper portion of the spinner table 2 in the radial direction. The cleaning water supply nozzle 13 is connected to a cleaning water supply source 14, and the compressed air supply nozzle 15 is connected to an air supply source 16.

  As shown in FIG. 1, the outer periphery holding | maintenance means 20 is provided with the liquid storage part 21 which has the upper surface 21a which can store a liquid. Further, the outer periphery holding means 20 includes a ring-shaped liquid supply port 22 that supplies a liquid toward the upper surface 21a of the liquid storage unit 21, and as shown in FIG. 21 communicates with a supply pipe 24 disposed in the interior. The supply pipe 24 is connected to a supply source 26 via an opening / closing valve 25. When the opening / closing valve 25 is opened, the liquid can be supplied from the liquid supply port 22 toward the upper surface 21a of the liquid storage unit 21.

  Furthermore, the outer periphery holding means 20 includes an elevating unit 23 that elevates and lowers the liquid storage unit 21. The elevating part 23 raises and lowers the liquid storage part 21 in the Z-axis direction by raising and lowering the piston 23a, and selectively positions the liquid storage part 21 at the action position P1 and the non-action position P2, as shown in FIG. be able to.

  As shown in FIG. 2, the action position P <b> 1 is the height of the liquid reservoir 21 when the upper surface of the liquid layer 6 stored on the upper surface 21 a of the liquid reservoir 21 is equivalent to the upper surface 3 of the spinner table 2. It refers to the position, and means the height position of the liquid reservoir 21 that can hold the outer periphery of the workpiece by the liquid layer 6. Therefore, if the workpiece can be held by the liquid layer 6, it is not necessary that the height of the upper surface of the liquid layer 6 and the height of the upper surface 3 of the spinner table 2 coincide completely. Further, the operation position varies depending on the thickness of the liquid layer 6. On the other hand, the non-operation position P2 refers to a position when the upper surface 21a of the liquid storage unit 21 is below the upper surface 3 of the spinner table 2, and the liquid storage in the case where the workpiece is not retained by the liquid layer 6. This means the height position of the part 21.

  The cleaning apparatus 1 can be applied to, for example, the grinding apparatus 30 shown in FIG. The grinding device 30 includes a base 31 extending in the Y-axis direction and a column 32 erected on the rear side of the base 31.

  A stage 33 a and a stage 33 b are formed at the front portion of the base 31 in the Y-axis direction. A cassette 34a that accommodates the workpiece before grinding is placed on the stage 33a, and a cassette 34b that accommodates the workpiece after grinding is placed on the stage 33b. In the vicinity of the cassette 34a and the cassette 34b, there is disposed a conveying means 35 for carrying out the workpiece before grinding from the cassette 34a and carrying the workpiece after grinding into the cassette 34b. In the movable region of the conveying means 35, a temporary placement means 36 for temporarily placing the work piece and a cleaning device 1 for cleaning the work piece after grinding are disposed.

  A rotatable turntable 37 is disposed on the upper surface of the base 31, and the turntable 37 supports a chuck table 38 that holds a workpiece and can rotate. On the side of the column 32, a grinding means 39 for grinding the workpiece is supported by the grinding feed means 40 so as to be movable up and down. The grinding means 39 can be moved up and down, and the grinding means 39 is provided with a grinding wheel 390 that is disposed in an annular shape and is rotatable.

  In the vicinity of the temporary placement means 36, a first transfer arm 41 for transferring the workpiece before grinding from the temporary placement means 36 to the chuck table 38 is disposed, and after the grinding, adjacent to the first transfer arm 41. A second transfer arm 42 for transferring the workpiece to the cleaning apparatus 1 is provided.

  The operation of the grinding device 30 when grinding the wafer W shown in FIGS. 1 and 2 in the grinding device 30 configured as described above will be described. The wafer W has a surface Wa to be ground, and a surface opposite to the surface Wa is a back surface Wb to be placed on the upper surface 3 of the spinner table 2. Furthermore, when the wafer W is placed on the upper surface 3 of the spinner table 2, the outer peripheral portion of the wafer W that protrudes from the upper surface 3 is the outer peripheral portion Wc.

  The wafer W before grinding is accommodated in the cassette 34 a and is transferred to the chuck table 38 by the transfer means 35. Then, after the wafer W is moved below the grinding means 39 by the rotation of the turntable 37, the chuck table 38 is rotated, the grinding means 39 is lowered while the grinding wheel 390 is rotated, and the grinding wheel 390 is moved to the wafer W. Grinding is performed in contact with the surface Wa.

  After the grinding of the surface Wa, the turntable 37 rotates and the wafer W is positioned in the vicinity of the cleaning apparatus 1. At this time, contaminants such as grinding dust adhere to the surface Wa of the wafer W.

  The wafer Wa after grinding is held on the surface Wa side by the second transfer arm 42 shown in FIG. 3, and transferred from the chuck table 38 to the spinner table 2 waiting in the transfer area 9a of the container 8, and the surface Wa is exposed. Held in a state. Then, the spinner table 2 descends in the Z-axis direction while holding the wafer W, and moves to the cleaning area 9b of the container 8 shown in FIG.

  As shown in FIG. 4, the outer peripheral portion Wc of the wafer W protruding from the spinner table 2 is held by the outer peripheral holding means 20. Specifically, the raising / lowering part 23 raises the piston 23a, and positions the liquid storage part 21 in the action position P1.

  After the liquid storage unit 21 is positioned at the operation position P <b> 1, the opening / closing valve 25 is opened to supply liquid to the supply pipe 24. As shown in FIG. 4, when the liquid is supplied from the liquid supply port 22 toward the upper surface 21a of the liquid storage unit 21 through the supply pipe 24, the liquid layer 6 is formed on the upper surface 21a. For example, pure water can be used as the liquid.

  At this time, since the liquid reservoir 21 is positioned at the action position P1, the upper surface 7 of the liquid layer 6 is positioned at substantially the same height as the upper surface 3 of the spinner table 2, and the outer periphery of the wafer W is surrounded by the liquid layer 6. The part Wc is held.

  Next, while the outer peripheral portion Wc of the wafer W is held by the liquid layer 6, the rotating shaft 5 rotates the spinner table 2 in the direction of arrow B, for example, to clean the surface Wa of the wafer W. Specifically, the sponge 11 is brought into contact with the front surface Wa of the wafer W and, for example, rotated in the direction of arrow A to perform scrub cleaning. During the cleaning of the wafer W, the cleaning water is continuously supplied from the cleaning water supply nozzle 13 to the surface Wa of the wafer W. In this way, the liquid layer 6 performs cleaning while holding the outer peripheral portion Wc of the wafer W, so that the entire surface of the wafer W can be cleaned even when the spinner table 2 has a smaller diameter than the wafer W. Moreover, since the back surface Wb on the outer peripheral portion Wc side of the wafer W is sealed by the liquid layer 6, the contamination on the front surface Wa of the wafer W does not go around the back surface Wb.

  After cleaning the surface Wa of the wafer W in this way, a drying step of the surface Wa of the wafer W is performed as shown in FIG. First, the piston 23a is lowered to position the liquid reservoir 21 at the non-operation position P2.

  Next, the rotating shaft 5 rotates, and the spinner table 2 is rotated at a high speed, for example, at a speed of 3000 rpm or more. At this time, the liquid adhering to the surface Wa is scattered using the centrifugal force generated on the surface Wa of the wafer W as the spinner table 2 rotates at a high speed. At the same time, compressed air is supplied from the compressed air supply nozzle 15 toward the surface Wa of the wafer W rotating at high speed. These operations are continued until the surface Wa of the wafer W is dried. When the wafer W is dried, the spinner table 2 rotates at a high speed, so that a centrifugal force is applied to the wafer W. Therefore, even if the liquid layer 6 is not formed, the outer peripheral portion Wc does not hang down.

As described above, the cleaning apparatus 1 includes the outer peripheral holding means 20 surrounding the spinner table 2, and the outer peripheral holding means 20 stores the liquid on the upper surface 21 a and forms the liquid layer 6, and the liquid Since the liquid supply port 22 for supplying the liquid to the upper surface 21a of the storage unit 21 and the elevating unit 23 for selectively positioning the liquid storage unit 21 at the operation position P1 and the non-operation position P2, the wafer cleaning is performed. In this case, the upper surface 7 of the liquid layer 6 formed in the liquid storage portion 21 becomes the same height as the upper surface 3 of the spinner table 2 by positioning the liquid storage portion 21 at the operation position P1. The portion Wc can be held, and the surface Wa of the wafer W can be scrubbed with the sponge 11.
Further, since the liquid layer 6 holds the outer peripheral portion Wc of the wafer W, the back surface Wb on the outer peripheral portion Wc side of the wafer W is sealed by the liquid layer 6, so that contamination on the front surface Wa of the wafer W wraps around the back surface. Can be prevented. Thereby, the back surface contamination of a wafer can be reduced.

1: Cleaning device 2: Spinner table 3: Upper surface 4: Porous member 5: Rotating shaft 6: Liquid layer 7: Upper surface 8: Container 9a: Transport area 9b: Cleaning area 10: Cleaning means 11: Scrub cleaning member 12: Support column 13: Wash water supply nozzle 14: Wash water supply source 15: Compressed air supply nozzle 16: Air supply source 17: Support unit 20: Peripheral holding means 21: Liquid storage unit 21a: Upper surface 22: Liquid supply port 23: Elevation Part 23a: Piston 24: Supply pipe 25: Open / close valve 26: Supply source 30: Grinding device 31: Base 32: Column 33a, 33b: Stages 34a, 34b: Cassette 35: Transfer means 36: Temporary placement means 37: Turntable 38: Chuck table 39: Grinding means
40: grinding feed means 41: first transfer arm 42: second transfer arm P1: working position P2: non-working position W: wafer Wa: front surface (surface to be cleaned) Wb: back surface Wc: outer periphery

Claims (1)

A spinner table that is formed smaller than the outer diameter of the wafer and that can rotate while holding the wafer on the upper surface,
Cleaning means for supplying cleaning water to the surface to be cleaned held on the upper surface of the spinner table to clean the surface to be cleaned;
An outer periphery holding means formed around the spinner table and supporting the outer periphery of the wafer with a liquid layer;
The outer periphery holding means stores a liquid on the upper surface and forms a liquid layer;
A liquid supply port for supplying liquid to the upper surface of the liquid storage section;
An elevating part that selectively positions the liquid storage part at the action position and the non-action position, and
In the working position, the upper surface of the liquid layer formed in the liquid reservoir is positioned at a height position equivalent to the upper surface of the spinner table,
In the non-operating position, the upper surface of the liquid reservoir is positioned below the upper surface of the spinner table,
During wafer cleaning, the liquid reservoir is positioned at the working position, liquid is supplied from the liquid supply port to the upper surface of the liquid reservoir, and the outer periphery of the wafer held on the upper surface of the spinner table is The wafer is rotated by the rotation of the spinner table and held by the liquid layer formed in the liquid reservoir, and the cleaning surface of the wafer is cleaned by the cleaning means,
A cleaning apparatus characterized in that when the wafer is dried, the liquid storage portion is positioned at the non-operation position, and the surface to be cleaned of the wafer is dried by rotating the spinner table at a high speed.

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