JP2018012178A - Inspection method for table top - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily inspect an upper surface shape of a holding table in a short time.SOLUTION: An inspection method of a table upper surface inspects an upper surface (32) shape of a holding table of a grinding device (30) including a holding table (31) for sucking and holding a plate-like workpiece (W), grinding means (41) which grinds the plate-like workpiece held on the holding table by a grinding wheel (46) with a grindstone (48) annularly arranged. The method includes: a placing process in which a block (B), having a flat surface having an area for covering the upper surface of the holding table, is placed and the upper surface is covered by the flat surface; and a measurement process in which the holding table is communicated with a suction source (51) and a suction pressure for sucking the block is measured. Suction pressure values (a1, a2, a3) measured in the measurement process are compared with a predetermined reference value (t), and it is determined that the upper surface shape is not normal when the suction pressure value does not reach the reference value.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a table top surface inspection method for inspecting a top surface shape of a holding table.

  In a grinding machine that holds a plate-like workpiece on a holding table and grinds with a grinding wheel, the upper surface of the holding table is formed in a conical shape, the grinding surface of the grinding wheel is positioned so as to be parallel to the conical slope, and the holding table A method of grinding a plate-like workpiece using a half region from the center toward the outer periphery is known (see, for example, Patent Document 1). The plate-like workpiece held in a conical shape on the holding table is ground by applying the grinding surface of the grinding wheel to the half region from the center of the plate-like workpiece toward the outer periphery in an arc shape. This grinding method is suitable for adjusting the thickness accuracy of the plate-shaped workpiece, but since the holding table is formed in a conical shape, the contact area of the grinding wheel with the plate-shaped workpiece is reduced, so that the plate-shaped workpiece can be ground. It may take time.

  When the upper surface of the holding table is formed into a flat surface and the plate-shaped workpiece is ground by bringing the grinding wheel into contact with the plate-shaped workpiece so that the grinding surface of the grinding wheel passes through the center of the upper surface of the holding table, It is possible to grind using a wide area extending from one end to the other end. Thereby, since the contact area with respect to the plate-shaped workpiece | work of a grinding stone can be enlarged, grinding time can be shortened.

JP 2014-030883 A

  When grinding a plate-like workpiece using a wide area that passes from one end of the outer periphery to the other end while passing through the center of the upper surface of the holding table, in order to maintain a large contact area of the grinding wheel with the plate-like workpiece, It is important that the shape of the upper surface of the holding table is good. In order to inspect the shape of the upper surface of the holding table, a method is conceivable in which a dial gauge is attached to the spindle shaft that rotates the grinding wheel, and the height of the upper surface is measured by moving the dial gauge on the upper surface of the holding table. Thereby, it can be determined whether the upper surface shape of the holding table is abnormal or normal. However, the installation and measurement work of the dial gauge is complicated and may take time.

  This invention is made | formed in view of this point, and it aims at providing the inspection method of the table upper surface which can test | inspect the upper surface shape of a holding table easily in a short time.

  The inspection method for the upper surface of the table according to one aspect of the present invention includes: a holding table that sucks and holds a plate-like workpiece; and a grinding unit that grinds the plate-like workpiece held by the holding table with a grinding wheel in which grinding wheels are arranged in an annular shape. A table top surface inspection method for inspecting the top surface shape of a holding table in a grinding apparatus comprising: a placing step of placing a block having a flat surface with an area covering the top surface of the holding table and covering the top surface with the flat surface; The measurement step of measuring the suction pressure when the holding table is connected to the suction source and sucking the block is compared with the reference value set in advance, and the suction pressure value reaches the reference value. A determination step of determining that the shape of the upper surface is not normal when not.

  According to this configuration, the block is sucked from the upper surface of the holding table, and the upper surface shape is determined using the suction pressure value obtained by measuring the suction pressure. Therefore, the measurement operation is easy and the measurement does not take time. . Therefore, the upper surface shape of the holding table can be easily inspected in a short time.

  According to the present invention, the upper surface shape of the holding table can be easily inspected in a short time.

It is a perspective view of the grinding device used for the grinding method concerning this embodiment. It is a figure which compares and demonstrates the change of the contact area of the grinding stone with respect to a plate-shaped workpiece. It is explanatory drawing of the shape of the upper surface of a holding table. It is explanatory drawing of the mounting process which concerns on this Embodiment. It is explanatory drawing of the measurement process which concerns on this Embodiment. It is explanatory drawing of the relationship between the mounting condition of the block which concerns on this Embodiment, and a suction pressure value, and a judgment process.

  Hereinafter, a table top surface inspection method according to the present embodiment will be described with reference to the accompanying drawings.

  First, the grinding apparatus used for the inspection method of the table upper surface which concerns on this Embodiment is demonstrated. FIG. 1 is a perspective view of a grinding apparatus used in the grinding method according to the present embodiment. FIG. 1A shows a state in which a plate-like workpiece is not placed on the grinding device according to the present embodiment, and FIG. 1B shows a state where the plate-like workpiece is placed on the grinding device according to the present embodiment and is ground. Indicates the state.

  As shown in FIGS. 1A and 1B, the grinding device 30 is provided with a holding table 31. Below the holding table 31, rotating means (not shown) for rotating the holding table 31 is provided. A holding surface 33 is formed on the upper surface 32 of the holding table 31 to attract the plate-like workpiece W (not shown in FIG. 1A) with a porous porous material. The holding surface 33 is connected to a suction source 51 (see FIG. 4) through a flow path 35 (see FIG. 4) in the holding table 31, and the plate-like workpiece W is sucked and held by the negative pressure generated on the holding surface 33. . The plate-like workpiece W may be a plate-like workpiece to be ground, and may be a semiconductor substrate such as silicon or gallium arsenide, an inorganic material substrate such as ceramic, glass, or sapphire, or a semiconductor product. The package substrate may be used.

  The grinding means 41 disposed above the holding table 31 is configured by providing a mount 44 at the lower end of a spindle 43 including a drive source such as a motor. On the lower surface of the mount 44, a grinding wheel 46 in which a plurality of grinding wheels 48 are arranged in a circular shape on a wheel base 47 is rotatably mounted. The diameter of the grinding wheel 46 is substantially the same as the diameter of the plate-like workpiece W. The grinding wheel 46 is rotated by driving the spindle 43. The plurality of grinding wheels 48 are constituted by, for example, segment grindstones in which diamond abrasive grains are hardened with a bonding agent such as metal bond. The plate-like workpiece W held on the holding table 31 is ground by the grinding wheel 48.

  When grinding the plate-like workpiece W, the plate-like workpiece W is placed on the holding surface 33 of the holding table 31 and is sucked and held by the holding table 31 by negative pressure. The plate-like workpiece W is rotated by the rotation of the holding table 31, and the rotating grinding wheel 46 is brought close to the upper surface 11 of the plate-like workpiece W. The plate-like workpiece W is ground by passing the grinding wheel 48 while contacting the plate-like workpiece W.

  Next, the contact area of the grinding wheel 48 with the plate-like workpiece W will be described with reference to FIG. FIGS. 2A and 2B are diagrams for comparing and explaining changes in the contact area of the grinding wheel with respect to the plate workpiece, FIG. 2A illustrates the contact area according to the present embodiment, and FIG. 2B illustrates the contact area according to the comparative example. Yes. Usually, the plate-like workpiece W is ground faster as the contact area with the grinding wheel 48 becomes larger. In this embodiment, in order to increase the contact area between the plate-like workpiece W and the grinding wheel 48, as shown in FIG. 2A, the other end C2 passes through the center O from one end C1 on the outer periphery of the upper surface 32 of the holding table 31. The plate-like workpiece W is ground so that the grinding wheel 48 passes through the entire region R1 that passes through. At this time, the grinding mark formed on the plate-like workpiece W becomes like an arc-shaped region R2, and the entire surface of the plate-like workpiece W is ground by the rotation of the holding table 31.

  On the other hand, when considering the case where the upper surface 72 of the holding table 71 is formed in a conical shape as a comparative example shown in FIG. 2B, the grinding wheel 78 contacts the plate-like workpiece W so as to be parallel to the conical slope. Is done. In this comparative example, as shown in FIG. 2B, the plate-like workpiece W is ground so that the grinding wheel 78 passes through the half region R3 from the center O of the holding table 31 toward the outer periphery. At this time, the grinding mark formed on the plate-like workpiece W becomes like a region R4 and is smaller than the region R2 shown in FIG. 2A. In other words, compared to the comparative example, in the present embodiment, the plate-like workpiece W can be ground in the region R2 to increase the contact area of the grinding wheel 48 with the plate-like workpiece W. The grinding time can be shortened. In the present embodiment, the contact area between the grinding wheel 48 and the plate-like workpiece W is adjusted by adjusting the inclination of the rotation shaft 31a of the holding table 31 or the inclination of the rotation shaft 43a of the spindle 43 (both see FIG. 1). Can be done.

  As in the present embodiment shown in FIG. 2A, in order for the plate-like workpiece W to be ground into the grinding wheel 48 in the region R <b> 2, the grinding wheel 48 passes through the entire region R <b> 1 of the holding table 31. The upper surface 32 needs to be formed. When the upper surface 32 of the holding table 31 is not well formed, the entire region R2 of the plate-like workpiece W is ground only by adjusting the inclination of the rotating shaft 31a of the holding table 31 or the inclination of the rotating shaft 43a of the spindle 43. The grindstone 48 cannot be brought into contact. That is, since the grinding wheel 48 grinds the plate-like workpiece W through only a part of the region R1 of the holding table 31, the contact area of the grinding wheel 48 with respect to the plate-like workpiece W is reduced and the plate-like workpiece W is reduced. The grinding time becomes longer. For this reason, when the shape of the upper surface 32 of the holding table 31 is inspected and the shape of the upper surface 32 of the holding table 31 is not good, self-grinding is performed in which the holding table 31 is ground with the grinding wheel 48.

  Here, a conventional method for inspecting the shape of the upper surface of the holding table will be described. A method for measuring the upper surface of the holding table with a dial gauge is known. In the conventional method, a dial gauge is attached to the spindle of the grinding means via a measuring jig. The dial gauge is attached to a position where the upper surface of the holding table moves along the same track as the grinding wheel when the spindle rotates with the lower end in contact with the upper surface of the holding table. Thereby, the height position of the upper surface is measured by the dial gauge, and the shape of the upper surface is determined from the measured value. However, the operation of attaching the dial gauge to the spindle using the measuring jig so as to be in a predetermined position is complicated, and it takes time from the operation of attaching the dial gauge to the measurement of the height position of the upper surface. Further, if the dial gauge is not properly attached, a measurement error may occur and the shape of the upper surface may not be accurately determined. Therefore, in the present embodiment, the shape of the upper surface 32 of the holding table 31 is inspected based on the measurement value of the suction pressure conventionally measured by the holding table 31.

  Here, the shape of the upper surface 32 of the holding table 31 will be described. FIG. 3 is an explanatory diagram of the shape of the upper surface of the holding table.

  FIG. 3A shows a case where the upper surface 32 of the holding table 31 has a flat shape. FIG. 3B shows a case where the vicinity of the center O of the upper surface 32 of the holding table 31 has a concave shape. FIG. 3C shows a case where the vicinity of the center O of the upper surface 32 of the holding table 31 has a convex shape. In the present embodiment, the upper surface 32 of the holding table 31 is inspected so that the shape of the upper surface 32 shown in FIGS. 3A to 3C can be determined.

  Next, a table top surface inspection method according to the present embodiment will be described in detail with reference to FIGS. The table top surface inspection method according to the present embodiment includes a placement process, a measurement process, and a determination process.

  First, the mounting process according to the present embodiment will be described. FIG. 4 is an explanatory diagram of the placing process according to the present embodiment. As shown in FIG. 4, in the grinding apparatus 30 used in the mounting process, the holding surface 33 is connected to a suction source 51 via a pipe 36, and a pressure gauge 52 is connected to the pipe 36. A determination unit 53 described later is connected to the pressure gauge 52. In the placing step, first, the block B is placed on the upper surface 32 of the holding table 31 to cover the upper surface 32. The block B is formed in a plate shape and includes a pair of main surfaces B1 and B2 on both sides in the thickness direction. These main surfaces B1 and B2 are formed as flat surfaces and have the same or larger area as the upper surface 32 of the holding table 31. The block B is placed so that one main surface B1, B2 (main surface B2 in the present embodiment) faces the upper surface 32 and covers the entire upper surface 32.

  Next, the measurement process according to the present embodiment will be described. FIG. 5 is an explanatory diagram of the measurement process according to the present embodiment. As shown in FIG. 5, the upper surface 32 of the holding table 31 is covered with the block B in the measurement process. By opening a valve (not shown) provided in the pipe 36, the suction source 51 and the holding surface 33 formed on the upper surface 32 are communicated, and the block B is sucked and held on the holding table 31 by the negative pressure generated on the holding surface 33. Is done. At this time, the suction pressure for the block B is measured by the pressure gauge 52. In general, when the plate-like workpiece W is held by the holding surface 33, the suction pressure value is measured by the pressure gauge 52, and when the block B is held by the holding surface 33, the suction pressure value is similarly measured by the pressure gauge 52. The

  Next, the mounting state of the block B and the suction pressure value in the measurement process will be described, and the determination process according to the present embodiment will be described. FIG. 6 is an explanatory diagram of the relationship between the placement status of the block and the suction pressure value and the determination process according to the present embodiment. 6A to 6C, the left diagram shows a state where the upper surface is self-ground, and the right diagram shows a state where the block according to the present embodiment is placed on the upper surface.

  In the determination step, the determination unit 53 compares the suction pressure value measured in the measurement step with a preset reference value t. When the suction pressure value does not reach the reference value t, it is determined that the shape of the upper surface 32 is not normal. A specific example will be described below. Here, the determination unit 53 includes a processor that executes various processes, a memory, and the like. The memory is composed of one or a plurality of storage media such as a ROM (Read Only Memory) and a RAM (Random Access Memory) depending on the application. The reference value t is a pressure value when the upper surface 32 is completely or almost completely blocked by the block B.

  6A, when the upper surface 32 of the holding table 31 and the grinding wheel 48 are brought into contact with each other so as to be parallel and the upper surface 32 is self-ground, the upper surface 32 is ground flat. 6A, when the block B is placed on the upper surface 32 of the holding table 31 (placement step), the upper surface 32 is covered with the block B without a gap. When the suction pressure is measured in this state (measuring step), the block B is sucked and held by the holding surface 33, so that the suction pressure value a1 is smaller than the reference value t (for example, a negative pressure is drawn to the negative pressure reference value t). When the pressure value a1 is reached), the determination unit 53 determines that the shape of the upper surface 32 is normal (determination step).

  In this case, when the plate-like workpiece W (not shown) is placed on the upper surface 32 after the inspection of the upper surface 32, the plate-like workpiece W is held along the flat shape of the upper surface 32. Therefore, as shown in FIG. 2A, the entire area of the plate-like workpiece W located in the area R <b> 1 of the holding table 31 contacts the grinding wheel 48. In other words, when the plate-like workpiece W is ground with the grinding wheel 48, there is no region in which the grinding wheel 48 and the plate-like workpiece W are separated from each other in the region R1, and the plate-like workpiece W is ground in the region R2. For this reason, the contact area between the plate-like workpiece W and the grinding wheel 48 is increased.

  As shown in the left diagram of FIG. 6B, when the upper surface 32 is self-ground so that the grinding wheel 48 strongly hits the vicinity of the center O of the upper surface 32 of the holding table 31, the upper surface 32 has a concave shape near the center O. To be ground. At this time, as shown in the right diagram of FIG. 6B, the upper surface 32 is covered with the block B so as to leave a gap in the vicinity of the center O and close in the vicinity of the outer periphery (placement step). When the suction pressure is measured in this state (measurement step), the block B is sucked and held by the holding surface 33, so the suction pressure value a2 is smaller than the reference value t, and the determination unit 53 has a normal shape of the upper surface 32. (Judgment process).

  In this case, when the plate-like workpiece W (not shown) is placed on the upper surface 32 after the inspection of the upper surface 32, the plate-like workpiece W is held along the concave shape of the upper surface 32. In the vicinity of the center O of the upper surface 32, the grinding wheel 48 is easily separated, and it is difficult to grind the plate-like workpiece W so that the grinding wheel 48 is not separated in the entire region R1 (see FIG. 2A). At this time, the inclination of the rotating shaft 31a of the holding table 31 or the inclination of the rotating shaft 43a of the spindle 43 is adjusted. Thereby, the whole area | region of the plate-shaped workpiece W located in area | region R1 including the center O vicinity can be made to contact the grinding stone 48, and the plate-shaped workpiece W is ground by area | region R2. For this reason, the contact area between the plate-like workpiece W and the grinding wheel 48 is increased.

  6C, when the upper surface 32 is self-ground so that the grinding wheel 48 is weakly applied to the vicinity of the center O of the upper surface 32 of the holding table 31, the upper surface 32 has a convex shape near the center O. So that it is ground. At this time, as shown in the right diagram of FIG. 6C, the upper surface 32 is covered with the block B so that a gap continuous with the outside is formed on the outer peripheral side (placement step). If the suction pressure is measured in this state (measurement process), the suction pressure value a3 becomes larger than the reference value t due to suction leakage (for example, the negative suction pressure value a3 does not reach the negative pressure reference value t). The part 53 determines that the shape of the upper surface 32 is not normal (determination step).

  In this case, when the plate-like workpiece W (not shown) is placed on the upper surface 32 after the inspection of the upper surface 32, the plate-like workpiece W is held along the convex shape of the upper surface 32. The grindstone 48 is easily separated in the vicinity of one end C1 and the other end C2 (see FIG. 2) on the outer periphery of the upper surface 32, and the plate-like workpiece W is ground so that the grinding wheel 48 is not separated in the entire region R1 (see FIG. 2A). I can't.

  When the vicinity of the center O of the upper surface 32 of the holding table 31 has a convex shape, the upper surface 32 may be formed in a conical shape or a truncated cone shape. Since the adjustment of the inclination of the rotating shaft 31a of the holding table 31 and the inclination of the rotating shaft 43a of the spindle 43 are different depending on which shape is formed, it is difficult to adjust the rotating shaft 31a and the rotating shaft 43a. For this reason, the whole area | region of the plate-shaped workpiece W located in area | region R1 cannot be made to contact the grinding stone 48, and the plate-shaped workpiece W may be unable to be ground in area | region R2. Therefore, the determination unit 53 controls the grinding means 41 so that the self-grounding of the upper surface 32 is performed again.

  As described above, in the determination step, the determination unit 53 determines whether the shape of the upper surface 32 of the holding table 31 is normal by comparing the suction pressure values a1, a2, and a3 measured in the measurement step with the reference value t. can do. As the pressure gauge 52, a conventional (existing) pressure gauge for confirming the suction holding state of the plate-like workpiece W can be used as it is. For this reason, in the measurement process, it is not necessary to connect the pressure gauge 52 to the pipe 36 for each measurement, and it is not necessary to attach a member such as a dial gauge to the grinding device 30. In addition, since a configuration in which the conventional plate-like workpiece W is sucked and held by the holding surface 33 can be used, the upper surface of the holding table 31 can be quickly formed with a simple configuration in which the upper surface 32 of the holding table 31 is covered with the block B. 32 shapes can be inspected.

  As described above, in the table top surface inspection method according to the present embodiment, the top surface 32 is sucked using the suction pressure values a1, a2, and a3 obtained by sucking the block B with the top surface 32 of the holding table 31 and measuring the suction pressure. Since the shape is determined, the operation for measurement is easy and the measurement does not take time. Therefore, the upper surface shape of the holding table can be easily inspected in a short time.

  In the above embodiment, the main surfaces B1 and B2 of the block B are configured to be flat surfaces. However, if the upper surface 32 of the holding table 31 can be covered, either the main surface B1 or the main surface B2 is used. Should be flat.

  The embodiments of the present invention are not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way by technological advancement or another derived technique, the method may be used. Accordingly, the claims cover all embodiments that can be included within the scope of the technical idea of the present invention.

  As described above, the present invention has an effect that the upper surface shape of the holding table can be easily inspected in a short time, and is particularly useful for a method for inspecting the upper surface shape of the holding table.

DESCRIPTION OF SYMBOLS 30 Grinding device 31 Holding table 32 (Top of holding table) 41 Grinding means 46 Grinding wheel 48 Grinding wheel 51 Suction source a1, a2, a3 Suction pressure value B block t Reference value W Plate workpiece

Claims (1)

Inspecting the shape of the upper surface of the holding table in a grinding apparatus comprising a holding table for sucking and holding a plate-like workpiece and a grinding means for grinding the plate-like workpiece held by the holding table with a grinding wheel in which a grinding wheel is annularly arranged. An inspection method for the upper surface of the table,
A placing step of placing a block having a flat surface covering the upper surface of the holding table and covering the upper surface with the flat surface;
A measuring step of measuring the suction pressure by which the holding table is communicated with a suction source and sucked the block;
A determination step of comparing the suction pressure value measured in the measurement step with a preset reference value and determining that the shape of the upper surface is not normal when the suction pressure value does not reach the reference value. Inspection method for the top surface of the table.

Images