JP6135626B2 - Non-contact holding device for workpieces - Google Patents

Description

  The present invention relates to a workpiece non-contact holding device.

A non-contact holding device for a work that floats and holds a plate-like work in a non-contact manner above a vibration plate that vibrates when the vibration of a vibrator is transmitted is known (for example, Patent Document 1).
Patent Document 1 discloses a technique for matching the outer dimension of a diaphragm with the outer dimension of a wafer.

As disclosed in Patent Document 1, the present inventor makes a plate-like workpiece above a vibration plate that vibrates when vibrations of a vibrator are transmitted by matching the outer dimensions of the vibration plate and the outer dimensions of the wafer. We made a prototype of a non-contact holding device for a workpiece that floats and holds it in a non-contact manner, and evaluated its performance.
In the apparatus described in Patent Document 1, when the work is disposed above the diaphragm, the work continued to swing in parallel to the diaphragm. Thereafter, the swing of the workpiece was settled, and the workpiece was positioned with respect to the diaphragm. However, it was confirmed that it took about 3 minutes for the workpiece to swing. Thereby, for example, when applied to a non-contact aligner of a semiconductor wafer, satisfactory performance cannot be obtained.

JP 2004-63984 A

  The present invention provides a non-contact holding device for a work that can shorten the time required for positioning the work above a diaphragm.

The first invention is
An ultrasonic levitation device that floats a plate-like workpiece at a target position and holds it in a non-contact manner above a vibration plate that vibrates when the vibration of the vibrator is transmitted;
A suction device that arranges an intake port below the work and performs suction from the intake port so that a suction force that attracts the intake port is applied to the work that directly covers the intake port; and Prepared,
An area coinciding with the diaphragm facing surface of the workpiece when the workpiece is held at a target position is a workpiece holding area,
A plurality of the air inlets are provided, and are arranged at a predetermined interval along the outer peripheral edge of the work holding region as viewed from above.

In the second invention,
The surface of the workpiece facing the vibration plate coincides with or substantially coincides with the upper surface of the vibration plate, or has a shape included in the upper surface of the vibration plate.

In the third invention,
The upper surface of the diaphragm has a perfect circle shape, and the vibration of the vibrator is transmitted to the center of the diaphragm to generate a concentric vibration abdominal node on the upper surface.
When viewed from above, the outer peripheral edge of the workpiece has a shape that substantially coincides with any one of the nodes generated on the upper surface of the diaphragm.

In the fourth invention,
The intake port is installed at a position where the inner wall surface is inscribed or substantially circumscribed with respect to the outer peripheral edge of the work holding region as viewed from above, and is separated from the work by a predetermined distance.

In the fifth invention,
Eight or sixteen intake ports are provided, and are arranged at equal intervals along the outer peripheral edge of the work holding region as viewed from above.

In the sixth invention,
The inlet has a diameter of 1.2 mm.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, when viewed from above, an annular boundary line surrounding all the intake ports is defined, and when the workpiece tries to escape outside the boundary line, the workpiece is moved against the diaphragm by the suction force. By tilting, the workpiece can be returned to the inside of the boundary line. Thereby, it can prevent that a workpiece | work escapes to the outer side of a boundary line, and can restrict | limit the rocking | fluctuation range of a workpiece | work. As a result, the time required for positioning the workpiece above the diaphragm can be shortened.

  According to the second invention, it is possible to position the workpiece in a non-contact manner by floating the workpiece above the upper surface of the diaphragm.

  According to the third invention, the work is held in a non-contact manner at a position where the outer peripheral edge thereof overlaps with a node (a node having the same shape as the outer peripheral edge) generated in the diaphragm as viewed from above.

  According to the fourth invention, the work is held without contacting the air inlet in the work holding area.

  According to the fifth aspect of the invention, the time required for positioning the workpiece above the diaphragm can be shortened, and the positioning accuracy of the workpiece can be improved.

  According to the sixth aspect of the invention, the time required for positioning the workpiece above the diaphragm can be shortened, and the positioning accuracy of the workpiece can be improved.

The schematic block diagram which shows the non-contact holding | maintenance apparatus of a workpiece | work. (A) The figure which looked at the workpiece | work and diaphragm of FIG. 1 from upper direction, (b) The top view which compared the shape of the outer periphery of a workpiece | work and the node produced in a diaphragm. (A)-(c) The top view which shows an example of the arrangement | positioning location of an inlet port. (A)-(c) Side surface sectional drawing which shows the principle in which the rocking | fluctuation range of a workpiece | work is controlled. (A)-(c) Side surface sectional drawing which shows the principle in which the rocking | fluctuation range of a workpiece | work is controlled. (A)-(c) Side surface sectional drawing which shows the principle in which the rocking | fluctuation range of a workpiece | work is controlled. The top view which shows the boundary line surrounding an inlet port. The top view which shows the boundary line surrounding an inlet port. The top view which shows the boundary line surrounding an inlet port. The top view which shows the space | interval of an inlet port. The top view which shows the modification of an inlet port. (A)-(d) The figure which shows an experimental result. (A)-(c) Side surface sectional drawing which shows the workpiece | work and diaphragm used for experiment.

  As shown in FIG. 1, the workpiece non-contact holding device 1 includes an ultrasonic levitation device 10 and a suction device 20.

  First, the ultrasonic levitation apparatus 10 will be described.

  As shown in FIG. 1, the ultrasonic levitation apparatus 10 is a plurality of (three in the present embodiment) stacked ring-shaped piezoelectric elements (piezo elements) 11 and bolted from both sides of the piezoelectric elements 11. And a so-called bolted Langevin type ultrasonic transducer 13 having a cylindrical metal block 12. Each piezoelectric element 11 is connected to a high-frequency power source, and the piezoelectric element 11 generates ultrasonic vibration when a high-frequency voltage is applied from the high-frequency power source. That is, the vibrator 13 functions as the vibrator described in the claims.

  A stepped composite horn (hereinafter simply referred to as “horn”) 16 that is a metallic member that amplifies and transmits ultrasonic vibration generated by the vibrator 13 is connected to one end of the vibrator 13. The horn 16 has a cylindrical portion 14 whose one end is joined to the vibrator 13 and a solid substantially conical (exponential) amplifying portion 15 that is integrally formed with the cylindrical portion 14 and amplifies ultrasonic vibration. It is comprised including. A metallic disk-like diaphragm 17 that vibrates in conjunction with the horn 16 is connected to the tip of the amplifying unit 15 of the horn 16 by welding or a screw. In addition, the vibrator | oscillator 13, the horn 16, and the diaphragm 17 are connected so that each center axis may correspond.

The ultrasonic levitation device 10 is a device that floats a plate-shaped workpiece 80 above the upper surface 17a of the diaphragm 17 by ultrasonic vibration and holds the workpiece 80 in a non-contact manner. The upper surface 17 a of the vibration plate 17 is a surface that faces the work 80 when the work 80 is floated above the vibration plate 17 by the ultrasonic levitation apparatus 10.
The workpiece 80 is a disk-shaped plate, and one plate surface (vibrating plate facing surface) 80a faces the upper surface 17a of the vibrating plate 17, and the other plate surface 80b faces upward. The workpiece 80 is, for example, a semiconductor wafer, a solar cell wafer, or the like. In addition, although the workpiece | work 80 of this embodiment is a disk shaped board, this invention is not limited to this, A polygonal board and the board containing R shape may be sufficient. Here, when the work 80 is stationary at the target position P, an area where the board surface (diaphragm facing surface) 80a exists is defined as a work holding area.

As shown in FIGS. 1 and 2A, the diaphragm facing surface 80 a of the workpiece 80 is smaller than the upper surface 17 a of the diaphragm 17 and has a shape included in the upper surface 17 a of the diaphragm 17.
As shown in FIG. 2B, the vibration plate 17 has an upper surface 17a having a perfect circle shape, and the vibration of the vibrator 13 is transmitted to the center of the vibration plate 17 so that concentric vibration antinodes are formed on the upper surface 17a. A knot occurs. In FIG. 2B, the solid thick circle is an antinode and the dotted thick circle is a node.
When viewed from above, the outer peripheral edge 81 of the workpiece 80 has a shape that coincides with any one of the nodes N generated on the upper surface 17a of the diaphragm 17 (work = node).

  Note that the diaphragm-facing surface 80a of the workpiece 80 may be configured to have a shape that coincides with (including substantially coincides with) the upper surface 17a of the diaphragm 17 (work = the outer shape of the diaphragm). In this case, when it is determined whether or not the diaphragm facing surface 80a of the workpiece 80 is coincident with the upper surface 17a of the diaphragm 17, the presence of the inlet 21 described later is not taken into consideration. Therefore, the diaphragm facing surface 80a of the workpiece 80 and the upper surface 17a of the diaphragm 17 are compared, and only the location of the intake port 21 (the location processed for installing the intake port 21) is different. Are matched (or substantially matched), the diaphragm facing surface 80 a of the workpiece 80 is matched with the upper surface 17 a of the diaphragm 17.

The operation of the ultrasonic levitation apparatus 10 will be described.
As shown in FIG. 1, when a high frequency voltage is applied to the piezoelectric element 11 constituting the vibrator 13, ultrasonic vibration having a frequency corresponding to the frequency of the applied voltage is generated. The ultrasonic vibration is input to the horn 16 and propagates in the horn 16 in the axial direction and is amplified by the amplifying unit 15. The amplified ultrasonic vibration is input to the vibration plate 17 and causes the vibration plate 17 to generate ultrasonic vibration. At this time, a concentric vibration abdominal node is formed on the upper surface 17a of the diaphragm 17. When the diaphragm 17 is ultrasonically vibrated, a squeezed air film is generated between the diaphragm 17 and the workpiece 80. As a result, an ultrasonic squeeze effect is generated, and a levitation force with respect to the workpiece 80 (a force that separates the workpiece 80 from the upper surface 17a of the diaphragm 17) is generated. As a result, the workpiece 80 floats above the upper surface 17a of the diaphragm 17.
The workpiece 80 swings in parallel with the upper surface 17 a of the diaphragm 17 in a state of floating with respect to the diaphragm 17. Then, the workpiece 80 gradually narrows the swing range, and finally stops at the predetermined position P (or a position slightly deviated from the predetermined position P). As a result, the workpiece 80 is held in a non-contact manner with respect to the diaphragm 17 (positioned state).

  With respect to the shape of the workpiece 80, when the workpiece is a node, the predetermined position (the target position) P is such that the outer peripheral edge 81 of the workpiece 80 overlaps the node N having the same shape as the outer peripheral edge 81 when viewed from above. Position (see FIG. 2B).

  Further, regarding the shape of the workpiece 80, when the workpiece is the outer shape of the diaphragm, the predetermined position P is such that the diaphragm facing surface 80a of the workpiece 80 coincides with the upper surface 17a of the diaphragm 17 when viewed from above. It is a position that overlaps.

  Next, the suction device 20 will be described.

  As shown in FIG. 1, the suction device 20 has an intake port 21 and a main body 22.

A through hole 23 is formed in the diaphragm 17 so as to penetrate in the plate thickness direction (vertical direction). The through hole 23 is opened at the upper surface 17 a of the diaphragm 17 to form an intake port 21. That is, the air inlet 21 is formed on the upper surface 17 a of the diaphragm 17.
The air inlet 21 is disposed below the workpiece 80 held in a non-contact manner by the ultrasonic levitation apparatus 10.
Although the inlet 21 of this embodiment is circular shape seeing from the upper direction, this invention is not limited to this, For example, polygonal shapes, such as a rectangle, may be sufficient. Further, it may be an arc-shaped long hole along the outer shape of the workpiece 80.

  The air inlet 21 is connected to the main body 22 through a through hole 23 and a hose 24. The main body 22 sucks air from the air inlet 21 through the through hole 23 and the hose 24 and exhausts the air to the outside.

The air inlet 21 is provided upward and sucks the air immediately above the air inlet 21. As a result, when the work 80 covers just above the air inlet 21, a suction force X attracted to the air inlet 21 acts on the work 80. Specifically, the suction force X attracted to the intake port 21 acts on a portion of the work 80 that is directly above the intake port 21.
The air inlet 21 is installed at a position separated from the work 80 by a predetermined distance. The predetermined distance is a distance such that the diaphragm facing surface 80a of the workpiece 80 does not come into contact with the air inlet 21 when it exists in the workpiece holding region.

The air inlet 21 is arranged at the edge of the work 80 existing at the predetermined position P (the edge of the work holding area) when viewed from above.
The edge of the workpiece 80 is as viewed from above (i) a position where the air inlet 21 is divided at the outer peripheral edge 81 of the workpiece 80 (the outer peripheral edge of the workpiece holding region) (see FIG. 3A), (Ii) a position where the inner wall surface of the intake port 21 circumscribes the outer peripheral edge 81 of the work 80 (the outer peripheral edge of the work holding region) (see FIG. 3B), and (iii) the inner wall surface of the intake port 21 is , A position (see FIG. 3C) inscribed in the outer peripheral edge 81 of the work 80 (the outer peripheral edge of the work holding area).
Note that (i) the state in which the intake port 21 is divided by the outer peripheral edge 81 of the work 80 is a part of the intake port 21 outside the outer peripheral edge 81 of the work 80 at a predetermined position P when viewed from above. In this state, the remaining portion of the air inlet 21 exists inside the outer peripheral edge 81 of the workpiece 80 at the predetermined position P (see FIG. 3A). Further, in this embodiment, when viewed from above, the outer peripheral edge 81 of the workpiece 80 existing at the predetermined position P and the outer peripheral edge of the workpiece holding region are coincident.

  Below, the principle by which the rocking | fluctuation range of the workpiece | work 80 is controlled is demonstrated.

First, (i) the case where the intake port 21 is divided by the outer peripheral edge 81 of the workpiece 80 will be described.
As shown in FIG. 4A, when the work 80 is arranged at the center of the left and right intake ports 21 and 21, the work 80 is in a stable state, and the work 80 is placed on the upper surface 17 a of the diaphragm 17. It becomes a parallel state.
When the workpiece 80 moves to the left from the state of FIG. 4A and the workpiece 80 is covered directly above the left intake port 21, the left end of the workpiece 80 has the suction force X. As a result, the workpiece 80 is attracted to the left air inlet 21 and the workpiece 80 is inclined with respect to the upper surface 17a of the diaphragm 17 (see FIG. 4B). As a result, the air pressure between the left air inlet 21 and the left end of the work 80 is increased, and a pressure difference is generated between the work 80 and the diaphragm 17 on the left and right.
As a result, the workpiece 80 receives the force Y toward the lower pressure side (right side) and returns to the right side (see FIG. 4B). When the workpiece 80 is returned to the right and the pressure difference is eliminated, the workpiece 80 returns to a state parallel to the diaphragm 17 (see FIG. 4C).
The same principle holds when the workpiece 80 moves to the right from the state shown in FIG. Accordingly, when the workpiece 80 moves to the right and covers right above the left intake port 21, the workpiece 80 is inclined with respect to the diaphragm 17 by the suction force from the left intake port 21, and to the left. Returned. When the workpiece 80 is returned to the left and the pressure difference is eliminated, the workpiece 80 returns to a state parallel to the diaphragm 17.
As described above, the workpiece 80 is inclined with respect to the diaphragm 17 by the suction force from the intake ports 21 and 21 when trying to escape to the outside of the intake ports 21 and 21 on both the left and right sides. • Returned to the inside of 21. As a result, the swing range of the workpiece 80 in the left-right direction is defined as a range S1 between both ends of the left and right intake ports 21 and 21 (see FIG. 4C).

  (Ii) Even when the inner wall surface of the air inlet 21 circumscribes the outer peripheral edge 81 of the workpiece 80, the same principle as in the above (i) holds (see FIGS. 5A to 5C). Therefore, the swinging range of the workpiece 80 in the left-right direction is defined as a range S2 between both end portions of the left and right intake ports 21 and 21 (see FIG. 5C).

(Iii) In the case where the inner wall surface of the intake port 21 is inscribed in the outer peripheral edge 81 of the workpiece 80, the same principle as in the above (i) is established (see FIGS. 6A to 6C). Therefore, the swinging range of the workpiece 80 in the left-right direction is defined as a range S3 between both end portions of the left and right intake ports 21 and 21 (see FIG. 6C).
In the case of (iii) above, when the workpiece 80 is shifted to the left or right even a little, it is tilted with respect to the diaphragm 17 and returned to its original position. As a result, the swing range of the workpiece 80 becomes narrower than in the cases (i) and (ii) (see FIGS. 4C, 5C, and 6C).

  Below, arrangement | positioning of the inlet 21 is demonstrated.

  A plurality of (preferably three or more) intake ports 21 are provided. In the present embodiment, eight intake ports 21 are provided.

FIG. 7 shows the arrangement of the intake ports 21 when (i) the intake ports 21 are provided at positions separated by the outer peripheral edge 81 of the work 80.
FIG. 8 shows the arrangement of the intake port 21 when (ii) the inner wall surface (inner peripheral surface) of the intake port 21 is provided at a position that circumscribes the outer peripheral edge 81 of the workpiece 80.
FIG. 9 shows the arrangement of the intake port 21 when (iii) the inner wall surface (inner peripheral surface) of the intake port 21 is provided at a position inscribed in the outer peripheral edge 81 of the workpiece 80.

  7 to 9 show annular boundary lines L1, L2, and L3 that surround all the intake ports 21 when viewed from above. The inner wall surfaces of all the intake ports 21 are inscribed in the boundary lines L1, L2, and L3 when viewed from above. Further, the boundary lines L1, L2, and L3 are virtually set above the upper surface 17a of the diaphragm 17. The suction device 20 tilts the workpiece 80 with respect to the diaphragm 17 by the suction force when the workpiece 80 swings and tries to escape to the outside of the boundary lines L1, L2, and L3. A pressure difference is generated between the workpiece 80 and the work 80 is returned to the inside of the boundary lines L1, L2, and L3. At this time, based on the principle shown in FIGS. 4A to 6C, the workpiece 80 is returned to the inside of the boundary lines L1, L2, and L3. Thereby, it can prevent that the workpiece | work 80 escapes to the outer side of boundary line L1, L2, and L3, and the rocking | fluctuation range of the workpiece | work 80 can be restrict | limited.

As shown in FIG. 10, the air inlets 21, 21... Are viewed along the outer peripheral edge 81 of the work 80 existing at the predetermined position P (along the outer peripheral edge of the work holding region). They are arranged with a predetermined interval d1, d2,.
The predetermined intervals d1, d2,... Are set from the viewpoint of defining the boundary lines L1, L2, L3 and limiting the swing range of the workpiece 80.
The predetermined distances d1, d2,... Are also set from the viewpoint of stably holding the workpiece 80 at the predetermined position P. For example, if the intake ports 21... Are arranged in one place, the air flow toward the intake ports 21. End up. This is because the workpiece 80 becomes unstable.
Therefore, the intervals d1, d2,... Between the intake ports 21, 21... Are arranged so that the intake ports 21, 21. Is set.
In the present embodiment, the intervals d1, d2,... Are equal to each other. .. Are arranged at equal intervals along the outer peripheral edge of the work holding area as viewed from above (d1 = d2 = d3...).

As described above, the air inlets 21, 21... Are arranged at predetermined intervals d 1, d 2, and so on along the outer peripheral edge of the work holding area as viewed from above.
As a result, the suction device 20 defines annular boundary lines L1, L2, and L3 that surround all the intake ports 21, 21,... As viewed from above, and the workpiece 80 is outside the boundary lines L1, L2, and L3. When the workpiece 80 is tilted with respect to the diaphragm 17 by the suction force, the workpiece 80 can be returned to the inside of the boundary lines L1, L2, and L3 (see FIGS. 7 to 9). . Thereby, it can prevent that the workpiece | work 80 escapes to the outer side of boundary line L1, L2, and L3, and the rocking | fluctuation range of the workpiece | work 80 can be restrict | limited. As a result, the time required to position the workpiece 80 above the diaphragm 17 can be shortened.

  In the present embodiment, the through hole 23 is formed in the diaphragm 17 and the air inlet 21 is formed in the upper surface 17a of the diaphragm 17. However, the present invention is not limited to this, and the outer peripheral portion of the diaphragm 17 is formed. The nozzle 25 may be depressed inside and the nozzle 25 may be disposed at the depressed portion, and the air inlet 21 may be formed at the tip of the nozzle 25 (see FIG. 11). That is, the air inlet 21 may be formed of a member different from the diaphragm 17.

  Below, the experimental result using the real machine of the non-contact holding | maintenance apparatus 1 is demonstrated.

The inventors of the present invention performed positioning of the workpiece 80 using the non-contact holding device 1, and measured (α) positioning accuracy and (β) settling time.
(Α) is a positional deviation amount of the workpiece 80 with respect to the predetermined position P when the workpiece 80 is positioned in a non-contact manner with respect to the diaphragm 17 by the non-contact holding device 1. This positional shift amount is a shift amount from the target position P in the direction parallel to the upper surface 17a of the diaphragm 17 (horizontal direction).
(Β) is a time (a settling time) required for the work 80 to be substantially stationary from the start of positioning and to be within the positional deviation amount. Here, the positioning start position was set at a position 5 mm away from the target position P.

First, the present inventor conducted an experiment using only the ultrasonic levitation device 10 without using the suction device 20. That is, the present inventor conducted an experiment using the diaphragm 17 in which the air inlet 21 and the through hole 23 are not formed. Therefore, in this experiment, the workpiece 80 is positioned only by the ultrasonic vibration of the ultrasonic levitation apparatus 10.
The inventor of the present invention (a) a configuration in which the diaphragm facing surface 80a of the workpiece 80 coincides with the upper surface 17a of the diaphragm 17 (work = outer shape of the diaphragm), and (b) the outside of the workpiece 80 when viewed from above. An experiment was performed with respect to a configuration in which the peripheral edge 81 coincides with any one of the nodes generated on the upper surface 17a of the diaphragm 17 (work = node).
As shown in FIG. 12A, in the case of the configuration of FIG. 12A (workpiece = external shape of the diaphragm), (α) was ± 0.5 mm, and (β) was about 3 minutes.
As shown in FIG. 12A, in the case of the configuration (b) (work = node), the work 80 continued to swing because the holding force of the work 80 by the ultrasonic vibration was weak. As a result, since the workpiece 80 was not easily positioned, the measurement of (α) and (β) was stopped.

  Next, the present inventor conducted an experiment for positioning the workpiece 80 using the ultrasonic levitation device 10 and the suction device 20. In addition, about the workpiece | work 80, the thing of the structure of said (b) was used.

First, the inventor conducted an experiment for optimizing the position of the air inlet 21. In this experiment, instead of changing the position of the air inlet 21, the diameter of the workpiece 80 was changed.
The present inventor, as viewed from above, (c) a configuration in which the intake port 21 is divided by the outer peripheral edge 81 of the workpiece 80 (see FIGS. 3A and 13A), and (d) the intake port 21. A configuration in which the inner wall surface is inscribed in the outer peripheral edge 81 of the workpiece 80 (see FIGS. 3C and 13B), and a configuration in which the air inlet 21 exists further inside than the configurations in FIGS. (See FIG. 13 (c)).
Eight intake ports 21 are provided, and are arranged at equal intervals along the outer peripheral edge of the work holding region as viewed from above. The diameter of the air inlet 21 is 1.2 mm.
As shown in FIG. 12B, in the case of the configuration of (c) (workpiece diameter = 139 mm), when the surface of the work 80 is opposed to the diaphragm 17, (α) is ± 2.0 mm, (Β) was 0.5 seconds. When the back surface of the workpiece 80 was opposed to the diaphragm 17, (α) was ± 2.8 mm, and (β) was 0.2 seconds.
As shown in FIG. 12B, in the case of the configuration of (d) (workpiece diameter = 141 mm), when the surface of the work 80 is opposed to the diaphragm 17, (α) is ± 0.8 mm, (Β) was 0.4 seconds. Further, when the back surface of the workpiece 80 was opposed to the diaphragm 17, (α) was ± 1.1 mm, and (β) was 0.3 seconds.
As shown in FIG. 12B, in the case of the configuration (e) (workpiece diameter = 141.5 mm), the work 80 is close to the diaphragm 17 and blocks all the intake ports 21. Thereby, (α) and (β) could not be measured.
According to the above experimental results, there was a difference in positioning accuracy between the front and back of the workpiece 80. Further, the configuration (d) had the highest positioning accuracy.
Moreover, it was confirmed that the configuration of (c) and (d) can significantly reduce the settling time compared to the configuration of (a).

Next, the present inventor conducted an experiment for optimizing the number of intake ports 21.
The inventor conducted experiments on the configuration (d) described above and the configuration in which the number of intake ports 21 in (f) and (d) was changed to sixteen. Note that the experiment was performed only when the surface of the workpiece 80 was opposed to the diaphragm 17.
As shown in FIG. 12C, in the case of the configuration of (d) (workpiece diameter = 141 mm, intake port: 8), (α) is ± 0.8 mm and (β) is 0.4 seconds. there were.
As shown in FIG. 12C, in the configuration of (f) (workpiece diameter = 141 mm, intake port: 16), (α) is ± 0.07 mm and (β) is 0.4 seconds. Met.
From the above experimental results, it was confirmed that the positioning accuracy was further improved by increasing the number of intake ports 21 to sixteen.

Next, the inventor conducted an experiment for optimizing the diameter of the air inlet 21.
The inventor conducted experiments on the configuration (f) and the configuration (g) (f) in which the diameter of the intake port 21 was changed to 0.5 mm.
As shown in FIG. 12D, in the case of the configuration (f) (intake port diameter = 1.2 mm), (α) was ± 0.07 mm and (β) was 0.4 seconds.
As shown in FIG. 12D, in the case of the configuration (g) (intake port diameter = 0.5 mm), (α) was ± 0.37 mm and (β) was 0.6 seconds.
From the above experimental results, it was confirmed that better results with respect to positioning accuracy and settling time can be obtained when the diameter of the air inlet 21 is 1.2 mm.

DESCRIPTION OF SYMBOLS 1 Non-contact holding | maintenance apparatus of a workpiece | work 10 Ultrasonic levitation apparatus 13 Vibrator 20 Suction apparatus 21 Inlet 80 Workpiece 81 Outer periphery

Claims (6)

An ultrasonic levitation device that floats a plate-like workpiece at a target position and holds it in a non-contact manner above a vibration plate that vibrates when the vibration of the vibrator is transmitted;
A suction device that arranges an intake port below the work and performs suction from the intake port so that a suction force that attracts the intake port is applied to the work that directly covers the intake port; and Prepared,
An area coinciding with the diaphragm facing surface of the workpiece when the workpiece is held at a target position is a workpiece holding area,
A plurality of the air inlets are provided, and are arranged at predetermined intervals along the outer peripheral edge of the work holding region as viewed from above.
Non-contact holding device for workpieces. The diaphragm-facing surface of the workpiece is coincident with or substantially coincides with the upper surface of the diaphragm, or has a shape included in the upper surface of the diaphragm.
The non-contact holding | maintenance apparatus of the workpiece | work of Claim 1. The upper surface of the diaphragm has a perfect circle shape, and the vibration of the vibrator is transmitted to the center of the diaphragm to generate a concentric vibration abdominal node on the upper surface.
The outer peripheral edge of the workpiece when viewed from above has a shape that substantially matches one of the nodes generated on the upper surface of the diaphragm,
The non-contact holding | maintenance apparatus of the workpiece | work of Claim 1 or Claim 2. The intake port is installed at a position where the inner wall surface is inscribed or substantially circumscribed on the outer peripheral edge of the workpiece holding region as viewed from above and separated from the workpiece by a predetermined distance. ,
The non-contact holding | maintenance apparatus of the workpiece | work as described in any one of Claims 1-3. Eight or sixteen intake ports are provided, and are arranged at equal intervals along the outer peripheral edge of the work holding region as viewed from above.
The non-contact holding | maintenance apparatus of the workpiece | work as described in any one of Claims 1-4. The intake port has a diameter of 1.2 mm,
The non-contact holding | maintenance apparatus of the workpiece | work as described in any one of Claims 1-5.

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