JP2005111571A - Processing method and processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method and a processing apparatus capable of reducing a correction plate having a small diameter and reducing deformation due to its own weight.
For example, when the surface of the workpiece 3 is a convex surface, the tilt mechanism 5 is slightly rotated in the direction of arrow D to incline the surface of the lapping surface plate 1. As a result, the contact pressure distribution between the lap surface plate 1 and the correction plate 2 changes so as to increase at a portion away from the rotation axis of the lap surface plate 1, so that the surface shape of the lap surface plate 1 can be corrected to a convex surface. it can. On the contrary, when the surface of the workpiece 3 is concave, the contact pressure distribution between the lapping platen 1 and the correction plate 2 is made to be the rotation axis of the lapping platen 1 by inclining in the direction opposite to the arrow D. Since it changes so that it may become large in the near part, the surface shape of the lap surface plate 1 can be corrected to a concave surface. Therefore, the convex and concave workpieces 3 can each be processed into a flat surface.
[Selection] Figure 2

Description

  The present invention relates to a method for lapping (polishing) and a polishing apparatus used therefor.

  High flatness is often required for optical components and structural members used in semiconductor-related precision equipment. Lapping and polishing are applied to the processing of these high precision parts. In these processing methods, a smooth surface is obtained by interposing loose abrasive grains between a workpiece and a processing surface plate (lapping surface plate) and sliding the workpiece and the processing surface plate while rotating them. It is a processing method.

  If the shape of the work piece is flat, the polishing process proceeds by rotating the flat lapping plate and sliding the lapping plate while rotating the work piece on the lapping plate. The method of making it is common. With the progress of removal of the non-workpiece surface by sliding with the lapping plate via the abrasive grains, the lapping plate shape can be transferred to the work piece to create a planar shape.

  For example, since a high running accuracy is required for the scanning portion of the exposure apparatus, the members constituting them must have high flatness. For the processing of such parts, the lapping or polishing described above is performed to obtain a smooth and flat surface.

  An example of such a method will be described with reference to FIG. First, the surface of the lapping surface plate 21 is flattened. The correction plate 22 is placed on the lap surface plate 21 that rotates in the direction of arrow I at the upper part of the apparatus main body 26, and is slid by being pressed against the lap surface plate 21 while being held by the rollers 25 and rotating in the direction of arrow J. Then, the processing of the lap surface plate 21 is advanced.

  At that time, a polishing liquid mixed with abrasive grains is interposed between the lapping platen 21 and the correction plate 22, and the surface of the lapping platen 21 is polished little by little with the abrasive particles, whereby the lapping platen is polished. 21 is created in a desired shape.

  After making the lap surface plate 21 into a desired shape, the workpiece is placed on the lap surface plate 21 and pressed against the lap surface plate 21 while rotating and sliding in the same manner as the correction plate 22. The surface is processed to obtain a desired flatness.

  Processing the lap surface plate 21 into a desired shape by the correction plate 22 is performed by moving the arm 23 attached with the roller 25 in the direction of arrow K using the linear stage 24 or the like, and the lap surface plate 21 and the correction plate. This was done by changing the position of 22 contact. Generally, when the distance between the rotation axis of the wrap surface plate 21 and the rotation axis of the correction plate 22 is reduced, the surface shape of the lap surface plate 21 becomes concave, and when the distance is increased, the surface shape becomes convex. Thus, the correction processing of the shape of the lap surface plate 21 is performed by adjusting the horizontal position of the correction plate 22.

  An example of a method for processing the surface shape of the lapping plate 21 will be described in more detail with reference to FIG. 7 is a schematic plan view and a schematic elevation view of the processing apparatus shown in FIG.

  A correction plate 22 and a workpiece 27 are arranged on the lap surface plate 21. In FIG. 7, the lapping platen 21, the correction plate 22, and the workpiece 27 are rotated in the directions of arrows E, F, and G, respectively, to perform processing. The figure shows a method of using a zonal portion by providing reliefs composed of recesses 28 and 29 in the center of the lap surface plate 21 and the correction plate 22, respectively. Processing is performed at the same time.

  For example, when the surface of the work piece 27 has a convex shape, the surface shape of the lapping surface plate 21 must also be corrected to a convex shape, and the convex portion of the surface of the work piece 27 must be removed. In such a case, as shown by an arrow H in FIG. 7, the correction plate 22 is moved so that the rotation axis of the correction plate 22 and the rotation axis of the lap surface plate 21 become far from each other. Thereby, the surface of the lapping surface plate 21 becomes a convex surface.

  On the contrary, when the surface of the workpiece 27 has a concave shape, the surface shape of the lapping surface plate 21 is also corrected to be concave, and the concave portion on the surface of the workpiece 27 must be removed. In such a case, the correction plate 22 is moved in the direction opposite to the direction indicated by the arrow H in FIG. 7 so that the rotation axis of the correction plate 22 and the rotation axis of the lap surface plate 21 are close to each other. Thereby, the surface of the lapping surface plate 21 becomes a concave surface.

  By using the method as described above, lapping and polishing were performed to obtain the accuracy of the workpiece.

  However, in the method of correcting the surface shape of the lap surface plate by changing the position of the correction plate as described above, the correction plate having a large diameter that can contact the ring zone portion of the lap surface plate at any position that moves with the correction. Was necessary. Further, when the portion where the correction plate does not come into contact with the ring zone portion of the lap surface plate becomes large, the correction plate undergoes its own weight deformation, and it is difficult to obtain the accuracy of the lap surface plate to be corrected.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a processing method and a processing apparatus that can reduce a correction plate having a small diameter and reduce deformation due to its own weight.

  The first means for solving the above-described problem is that the rotating processing platen and the processing surface of the rotating workpiece are slid relative to each other, and the removal of the surface (processing surface) of the processing object proceeds. In addition, in the lapping (polishing) for correcting the surface shape of the processing surface plate by sliding the processing surface plate and the rotating correction plate relative to each other, the processing surface plate is inclined with respect to a horizontal plane. It is a processing method (Claim 1) characterized by having the process of performing.

  In this means, the lap surface plate is inclined with respect to the horizontal plane for processing. As a result, the contact pressure distribution between the correction plate and the lapping platen can be changed as will be described in detail later in the section “Best Mode for Carrying Out the Invention”. The shape can be controlled. Therefore, since there is no need to move the correction plate as in the prior art, the correction plate can be made smaller by that amount, and the portion that does not come into contact with the wrap surface plate is reduced, so that the weight of the correction plate is not easily deformed. . Therefore, the surface processing accuracy of the lapping surface plate can be improved.

  The second means for solving the above-mentioned problem includes a rotating processing platen, a mechanism for holding and rotating the non-workpiece, and contacting the processing platen and the non-workpiece and applying pressure between them. And a mechanism for holding and rotating the correction plate, and a mechanism for bringing the processing platen and the correction plate into contact with each other and generating pressure therebetween, and further, a rotating shaft of the processing platen It is a processing apparatus (Claim 2) which performs the lapping process (polishing process) characterized by having a mechanism which inclines from the vertical direction.

  According to this means, since the mechanism has a mechanism for tilting the rotation axis of the processing surface plate from the vertical direction, the processing surface plate can be inclined with respect to the horizontal surface, and the processing method as the first means can be performed. Can be implemented.

  As described above, according to the present invention, it is possible to provide a processing method and a processing apparatus capable of reducing a correction plate having a small diameter and reducing deformation due to its own weight in lapping (polishing). Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are a schematic plan view and a schematic elevation view showing an outline of a processing apparatus as a first example of an embodiment of the present invention. A correction plate 2 is arranged on one side of the upper surface of the lapping surface plate 1, and a workpiece 3 is arranged on the other side. The lapping surface plate 1, the correction plate 2 and the workpiece 3 rotate in the directions of arrows A, B and C, respectively. To do. The correction plate 2 and the workpiece 3 are pressed against the lapping surface plate 1. A polishing liquid is supplied onto the lapping platen 1, whereby the correction plate 2 and the workpiece 3 slide with each other through the polishing liquid. In the central portion of the lapping platen 1, a relief formed by the concave portion 7 is provided, and in the central portion of the correction plate 2, a relief formed by the concave portion 8 is provided.

  A rotating shaft 4 that rotates in the direction of arrow A together with the lap surface plate 1 is fixed to a tilt mechanism 5 that can tilt the lap surface plate 1 with respect to a horizontal plane, and the tilt mechanism 5 is attached to the apparatus body 6. Yes. Usually, as shown in FIG. 1, processing is performed with the upper surface of the lapping platen 1 being horizontal.

  For example, when the surface of the workpiece 3 is convex, the tilt mechanism 5 is slightly rotated in the direction of arrow D as shown in FIG. As a result, the contact pressure distribution between the lap surface plate 1 and the correction plate 2 changes so as to increase at a portion away from the rotation axis of the lap surface plate 1, so that the surface shape of the lap surface plate 1 can be corrected to a convex surface. it can.

  On the contrary, when the surface of the workpiece 3 is concave, the contact pressure distribution between the lapping platen 1 and the correction plate 2 is made to be the rotation axis of the lapping platen 1 by inclining in the direction opposite to the arrow D. Since it changes so that it may become large in the near part, the surface shape of the lap surface plate 1 can be corrected to a concave surface. Therefore, the convex and concave workpieces 3 can each be processed into a flat surface.

  Since the pressure distribution can be changed by inclining the lapping platen 1, there is no need to move the correction plate 2, and the correction can be made with the correction plate 2 having a smaller diameter than the conventional one. Further, by reducing the diameter of the correction plate 2, the area where the correction plate 2 and the lap surface plate 1 do not contact with each other is reduced. Thereby, the deformation | transformation by the dead weight of the correction plate 2 can be made small, and it becomes possible to correct the surface of the lapping surface plate 1 with high precision.

  The effect of reducing the diameter of the correction plate as compared with the conventional case is particularly effective in a large apparatus. However, it is difficult to realize a large apparatus with the structure shown in FIGS. The example of the processing apparatus which is the 2nd Embodiment of this invention corresponding to this is shown in FIG.3, FIG.4, FIG.5. In these drawings, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In the apparatus shown in FIGS. 3 to 5, the lap platen 1 is inclined using hydraulic jacks 11 and 12. As described above, the correction plate 2 is placed on the lap surface plate 1, and the rotational motion (arrow M) can be given by the joint 13 capable of forced rotation. The joint 13 gives only rotation M, and the correction plate 2 can move freely following the lapping platen 1 in the horizontal direction. The correction plate 2 may be supported by a roller or the like and rotated by a frictional force with the lap platen 1.

  The lap platen 1 rotates in the direction of arrow L by rotating the rotating shaft 14 below the lap platen 1 with a motor 15. The lap surface plate 1 is rotatably supported by a bearing 16, and the lap surface plate 1 is inclined by raising and lowering the base of the bearing with hydraulic jacks 11 and 12.

  If the hydraulic jack 11 is raised in the N direction as shown in FIG. 4 and the hydraulic jack 12 is lowered in the O direction, the lap surface plate 1 is corrected to a convex surface, and the hydraulic jack 11 is moved in the P direction as shown in FIG. If the hydraulic jack 12 is lowered and the hydraulic jack 12 is raised in the Q direction, the lap platen 1 is corrected to the concave surface. Although two jacks are shown in the cross-sectional view, in practice, a plurality of jacks may be provided to adjust the inclination of the lap surface plate 1.

  By correcting and processing the lapping plate by the above method, the accuracy of the lapping plate can be maintained and corrected stably and easily, and the workpiece can be lapped and polished with high accuracy. it can.

Using the apparatus shown in FIGS. 3 to 5, processing was actually performed using the method of the present invention.
Cast iron was used as the material for the lapping surface plate 1 and the correction plate 2, and the workpiece was ceramic. A workpiece 3 of 80 × 30 mm was machined using a lapping platen 1 having a diameter of 300 mm and a width of the annular zone of 100 mm (that is, the diameter of the concave portion 7 at the center is 100 mm). The diameter of the correction plate 2 was 120 mm, and the lapping liquid used was a mixture of fine particles of GC abrasive grains in water. The lapping plate 1 rotating at 20 rpm while supplying the lapping solution and the workpiece 3 were slid to perform lapping. The surface shape of the lap surface plate 2 was corrected by inclining the lap surface plate 1 ± 3 degrees. As a result, the desired accuracy could be obtained in a short time even if the diameter and thickness of the correction plate 2 were reduced by 15 to 20% of the conventional product.

It is a schematic diagram showing an outline of a processing device which is a first example of an embodiment of the present invention. It is a schematic diagram showing an outline of a processing device which is a first example of an embodiment of the present invention. It is a schematic diagram which shows the outline | summary of the processing apparatus which is the 2nd example of embodiment of this invention. It is a schematic diagram which shows the outline | summary of the processing apparatus which is the 2nd example of embodiment of this invention. It is a schematic diagram which shows the outline | summary of the processing apparatus which is the 2nd example of embodiment of this invention. It is a figure which shows the outline | summary of the conventional lapping (polishing) processing apparatus. FIG. 7 is a schematic plan view and an elevation view of the processing apparatus shown in FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lap surface plate, 2 ... Correction plate, 3 ... Workpiece, 4 ... Rotating shaft, 5 ... Tilt mechanism, 6 ... Apparatus main body, 7 ... Recessed part, 8 ... Recessed part, 11 ... Hydraulic jack, 12 ... Hydraulic jack, 13 ... Joint, 14 ... Rotating shaft, 15 ... Motor, 16 ... Bearing

Claims (2)

A rotating processing platen and a processing surface of the rotating workpiece are slid relative to each other to advance the removal of the surface of the workpiece (processing surface), and the processing platen and a rotating correction plate; In a lapping process (polishing process) for correcting the surface shape of the processing surface plate, the processing method includes a step of performing processing by inclining the processing surface plate with respect to a horizontal plane. A rotating processing surface plate, a mechanism for holding and rotating a non-workpiece, a mechanism for causing the processing surface plate and the non-workpiece to contact each other and generating pressure between them, and holding and rotating a correction plate And a mechanism for causing the processing platen and the correction plate to contact each other and generating pressure therebetween, and further, a mechanism for tilting the rotation axis of the processing platen from the vertical direction. Processing equipment that performs lapping (polishing).

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