Processing device

Abstract

To form a protective member of uniform thickness into a wafer without tilting a processing unit.SOLUTION: A processing device 1 includes three vertical moving mechanisms 4 arranged at the apex of a triangle formed in a horizontal direction having, as a center, a center of gravity of a processing unit 6, coupling a lower base 32 and an upper base 53 that support a work-piece holding table, and vertically moving the processing unit 6 together with a support base 50 supporting the processing unit 6; wherein the vertical moving mechanism 4 includes: a ball screw 41 that spirally engages with a nut 40 of the support base 50; a ball-screw rotating motor 42; and a scale that measures a height of a nut, using a table upper surface as a reference; and wherein control means 9 includes: a setting unit 92 that sets a movement distance for the nut 40; and a correction unit 94 that calculates a corrected rotation angle for the motor 42 so that the measured height of the height of the nut 40 moved under motor control by a rotation control unit 91 is equal to a set height of the nut 40 when the nut 40 is moved by a set movement and that moves the nut 40 by a corrected value corresponding to the corrected rotation angle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a processing device that processes a workpiece by applying a load to the workpiece. [Background technology]

[0002] For example, a grinding device such as that disclosed in Patent Document 1 includes a holding means for rotatably holding a wafer on a holding surface, a grinding means having a spindle on which a grinding wheel with grinding stones arranged in a ring is rotatably mounted, and a grinding feed means for moving the grinding means in a direction perpendicular to the holding surface.

[0003] When grinding a wafer, the grinding means is moved toward the holding means by the grinding feed means, and the entire upper surface of the rotating wafer is ground by the holding means while the lower surfaces of the annular grinding wheels of the grinding means are brought into contact with the radial area of the wafer. The grinding feed means is configured to rotate a ball screw using a motor, converting the rotational motion of the ball screw into vertical linear motion of the grinding means. In other words, during grinding, the lower surfaces of the annularly arranged grinding wheels contact the radial area of the wafer in an arc-shaped manner in a plan view. Therefore, a load is applied only to the portions of the annularly arranged grinding wheels that are in contact with the wafer, which can cause the grinding means to tilt relative to the direction perpendicular to the holding surface.

[0004] As a countermeasure to this problem, for example, the technology disclosed in Patent Document 2 arranges two guide rails that guide the movement of the grinding means in the grinding feed direction so that they extend perpendicular to the holding surface, sandwiching the grinding means, thereby reducing the tilt that occurs in the grinding means due to the reaction force against the load applied to the wafer when the grinding wheel comes into contact with the wafer. Furthermore, for example, Patent Document 3 discloses a technology in which guide rails are arranged at the vertices of a triangle centered on the center of the grinding means in a plan view, thereby reducing the tilt of the grinding means caused by the reaction force against the load applied to the wafer when the grinding wheel comes into contact with the wafer.

[0005] For example, Patent Document 4 discloses a protective member forming device that spreads and hardens a liquid resin on one surface of an as-sliced wafer sliced from a silicon ingot to form a protective member before grinding the as-sliced wafer with a grinding wheel to remove warpage of the as-sliced wafer and waviness of the cut-out surface. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-200545 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-014877 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-040620 [Patent Document 4] Japanese Patent Application Publication No. 2017-168565 Summary of the Invention [Problem to be solved by the invention]

[0007] However, even if the grinding device uses the configuration disclosed in Patent Document 2 or Patent Document 3, tilting of the grinding means may occur. In addition, tilting of the grinding means may also occur due to, for example, individual differences in the pitch intervals of the ball screws of the multiple grinding feed means. Therefore, there is a problem to be solved to prevent the grinding means from tilting when the grinding wheel comes into contact with the wafer, so that the wafer can be ground to a uniform thickness.

[0008] In addition, a protective member forming apparatus as disclosed in Patent Document 4 supplies a predetermined amount of liquid resin to a film sheet held on a glass stage, presses and spreads the liquid resin from above with a wafer held by holding means, and then cures it by irradiating ultraviolet rays or the like to form a protective member. When spreading the liquid resin, a load is applied to the holding means and the glass stage. If the holding means for sucking and holding the wafer is tilted by this load, there is a problem that a protective member with a uniform thickness cannot be formed on the wafer. Further, the tilt of the holding means can also be caused by, for example, an individual difference in the pitch interval of each ball screw constituting a plurality of holding means elevating mechanisms for moving the holding means up and down. Therefore, there is a problem to be solved in that a protective member with a uniform thickness is to be formed on the wafer without tilting the holding means.

Means for Solving the Problems

[0009] The present invention for solving the above problems includes a table for holding a workpiece on its upper surface, and a processing unit having a lower surface facing the upper surface of the table, and applies a load to the workpiece between the upper surface of the table and the lower surface of the processing unit to grind the workpiece with a grinding wheel or apply a load to supply the liquid resin to one surface side of the workpiece and spread it on the one surface to cure the liquid resin to form a protective member for protecting the one surface. The processing apparatus is a lower base that supports the table from below, a support base that supports the processing unit from above, an upper base that is disposed opposite to the lower base so as to sandwich the support base between the lower base and the upper base, and is disposed at the apex of a triangle formed horizontally around the center of gravity of the processing unit, connects the lower base and the upper base, and moves the support base in a direction perpendicular to the upper surface of the table between the upper base and the lower base to move the processing unit in the vertical direction. Three vertical movement mechanisms, and control means for controlling each of the three vertical movement mechanisms. The vertical movement mechanism includes a nut disposed on the support base, a ball screw that is screwed into the nut and extends in the vertical direction, a fixed-side bearing that is fixed to the lower surface of the upper base and is connected to the upper end side of the Ball screw and a fixed-side bearing fixed to the upper surface of the lower base and the Ball screwA support-side bearing that supports the lower end side thereof, and the fixed-side bearing is interposed therebetween and the Ball screw A motor that is connected to the upper end side of the ball screw and rotates the ball screw, a guide rail that is arranged in parallel with the ball screw and guides the vertical movement of the support base, an upper end side that is removably fixed to the side surface of the fixed-side bearing and a lower end side that is removably fixed to the upper surface of the support-side bearing, and a scale that measures the height of the nut based on the upper surface of the table, and a counterbalance that connects the upper base and the support base and reduces and offsets the self-weights of the processing unit and the support base. The counterbalance, the guide rail, and the ball screw are arranged outward from the center side of the triangle in this order. The control means includes a rotation control unit that rotates the motor to move the nut, a setting unit that sets the movement distance of the nut by the rotation control unit, and the height of the nut arranged on the support base that has moved by rotating the ball screw under the control of the motor by the rotation control unit is measured by the scale, and a correction unit that calculates a correction rotation angle of the motor so that the measured height matches the set height of the nut when the nut is moved by the movement distance set by the setting unit, and further moves the nut by an amount corresponding to the correction value corresponding to the correction rotation angle. It is a processing apparatus provided with.

[0010] The control means includes a storage means for storing the correction value in the correction unit. After storing the correction value in the correction unit, control may be performed to match the height of the nut with the set height using the stored correction value without measuring the height of the nut with the scale.

[0011] In the processing apparatus according to the present invention, the correction unit includes a plurality of correction data tables corresponding to the set height. The correction data table includes the set height, which is the height of each nut from the upper surface of the table for raising the processing unit by the moving distance set in the setting unit from the height position closest to the upper surface of the table, and the measured actual height, which is the height of each nut from the upper surface of the table measured by the scale when the motor is rotated by a predetermined angle to raise the nut by the moving distance set in the setting unit from the height position closest to the upper surface of the table, and a correction value for making the difference between the measured actual height and the set height zero. It is preferable that the correction unit is provided with these components.

[0012] In the processing apparatus according to the present invention, it is preferable that the correction unit calculates the correction value between another correction value adjacent to the correction value by linear interpolation or curve interpolation.

Effects of the Invention

[0013] It should be noted that there seems to be a typo in the original text where "<O000066>" should probably be " ". This has been left as is in the translation to maintain consistency with the original.The processing apparatus according to the present invention for processing a workpiece by applying a load to the workpiece between the upper surface of a table that holds the workpiece and the lower surface facing the upper surface of the table includes a lower base that supports the table from below, a support base that supports the processing unit, an upper base that is disposed opposite to the lower base so as to sandwich the support base between the lower base, and three vertical movement mechanisms that are disposed at the vertices of a triangle formed horizontally around the center of gravity of the processing unit, connect the lower base and the upper base, and move the support base in the vertical direction with respect to the upper surface of the table and move the processing unit in the vertical direction, and control means for controlling each of the three vertical movement mechanisms. The vertical movement mechanism includes a nut disposed on the support base, a ball screw that is screwed into the nut and extends in the vertical direction, a motor that is connected to the ball screw and rotates the ball screw, a guide rail that is disposed in parallel with the ball screw and guides the vertical movement of the support base, and a scale that measures the height of the nut with reference to the upper surface of the table. The control means includes a rotation control unit that rotates the motor to move the nut, a setting unit that sets the movement distance of the nut by the rotation control unit, and a correction unit that calculates a correction rotation angle of the motor so that the measured height of the nut disposed on the support base that has been rotated and moved by rotating the ball screw under the control of the rotation control unit matches the set height of the nut when the nut is moved by the movement distance set by the setting unit, and further moves the nut by a correction value corresponding to the correction rotation angle. By providing this, tilt correction of the processing unit is performed so that the tilt of the processing unit does not change even when the processing unit receives a load (reaction force from the table side) during processing of the workpiece, and thus it becomes possible to form a protective member having a uniform thickness on the workpiece or grind the workpiece to a uniform thickness.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0015] FIG. 1 shows a processing apparatus 1 that includes a table 30 that holds a workpiece 80 on an upper surface 3000 facing the +Z direction side, and a processing unit 6 that has a lower surface 601 facing the upper surface 3000 of the table 30, and that applies a load to the workpiece 80 between the upper surface 3000 of the table 30 and the lower surface 601 of the processing unit 6 to process the workpiece 80.

[0016] Specifically, the processing apparatus 1 is an apparatus that spreads a liquid ultraviolet curable resin over the entire lower surface 800 of the workpiece 80 and then irradiates it with ultraviolet rays to cure it, forming a protective member on the lower surface 800. The processing unit 6 is a unit that sucks and holds the upper surface 801 of the workpiece 80 and lowers it to perform a process of spreading a liquid resin that becomes a protective member on the lower surface 800. Note that the processing apparatus 1 may be a grinding apparatus that contacts a rotating grinding wheel of a grinding means, which is the processing unit 6, with the upper surface 801 of the workpiece 80 sucked and held on the table 30 from above to thin the workpiece 80 to a desired thickness.

[0017] The workpiece 80 shown in FIG. 1 is, for example, a circular az slice wafer formed by thinly cutting a cylindrical silicon ingot with a wire saw or the like, but is not limited thereto. For example, the workpiece 80 may be a semiconductor wafer in which devices are formed in regions partitioned by a planned division line on the lower surface 800.

[0018] The table 30 shown in FIG. 1 has an outer shape that is circular in plan view, and includes, for example, a glass stage 300 such as quartz glass and a frame body 301 having a circular recess for supporting the glass stage 300. A sheet 82 is placed on the flat upper surface 3000 of the glass stage 300, and a liquid resin is stored on the sheet 82. For example, the upper surface 3000 of the glass stage 300 is set to be larger than the lower surface 800 of the workpiece 80.

[0019] For example, the upper surface of the frame body 301 is set to be slightly higher than the upper surface 3000 of the glass stage 300 so that the liquid resin stored on the upper surface 3000 of the glass stage 300 does not overflow outside the table 30.

[0020] For example, the table 30 is fixed to a table base 31 that is circular in plan view by bolts or the like (not shown), and is supported from below (-Z direction side) by the lower base 32 shown in FIGS. 1 and 2 via the table base 31. The lower base 32 is formed, for example, in a substantially regular triangular ring shape in plan view, and has an opening 320 for accommodating the table 30 and the table base 31. As shown in FIG. 3, mounting portions 323 that protrude toward the plane center side of the lower base 32 are formed at three locations in the circumferential direction of the inner surface of the lower base 32 within the opening 320 at 120-degree intervals. Then, the table base 31 is supported by the three mounting portions 323.

[0021] For example, the table base 31 and the frame 301 are made of a material that transmits ultraviolet rays, and an ultraviolet irradiation lamp (not shown) may be disposed at a position below the table base 31 within the opening 320 of the lower base 32. Then, the ultraviolet rays irradiated upward from the ultraviolet irradiation lamp and transmitted through the glass stage 300 cure the ultraviolet curable resin that is stored via the sheet 82 on the upper surface 3000 of the table 30, pressed by the workpiece 80 from above, and spread over the entire lower surface 800 of the workpiece 80.

[0022] When the processing apparatus 1 is a grinding apparatus, the table 30 is a chuck table made of a porous member or the like and having a holding surface that is an extremely gentle conical slope with the rotation center as the apex and cannot be judged by the naked eye, and can suck and hold the workpiece 80. In this case, the chuck table supported by the lower base 32 can have the inclination of the holding surface adjusted by inclination adjusting means such as a plurality of ball screw mechanisms arranged at equal intervals in the circumferential direction of the chuck table below the chuck table. By adjusting the inclination of the chuck table, it becomes possible to make the holding surface parallel to the lower surface of the grinding wheel of the grinding means, which is the processing unit 6.

[0023] In the present embodiment, the processing unit 6 shown in FIGS. 1, 2, and 3 includes, for example, a wheel 60 having a circular shape in plan view, and a holding portion (not shown) made of a porous member or the like and supported by the wheel 60 for sucking and holding the workpiece 80. The circular plate-shaped holding portion (not shown) is, for example, fitted on the lower surface side of the wheel 60, communicates with a suction source such as a vacuum generator, and the suction force generated by the suction of the suction source is transmitted to the flat lower surface 601 of the holding portion parallel to the horizontal plane (X-axis Y-axis plane) of the holding portion, so that the processing unit 6 can suck and hold the workpiece 80 on the lower surface 601.

[0024] As shown in FIG. 3, on the upper surface of the wheel 60 of the processing unit 6, for example, when the workpiece 80 held (see FIGS. 1 and 2) is pressed against the liquid ultraviolet curable resin on the table 30 from the +Z direction side, a plurality of load sensors 61 for measuring the load (reaction force) applied to the workpiece 80 from the table 30 side are arranged. The load sensors 61 are arranged, for example, six on the upper surface of the wheel 60 at intervals of 60 degrees in the circumferential direction of the wheel 60. In this embodiment, the six load sensors 61 are respectively sandwiched from above and below by the wheel 60 and a unit coupler 66 shown in FIGS. 2 and 4 described later, and are arranged so as to be the acting point portions where the load in the +Z direction applied to the workpiece 80 from the table 30 side acts. The load sensor 61 is composed of, for example, a thin force sensor manufactured by Kistler using a piezoelectric element such as lead zirconate titanate (PZT).

[0025] When the processing apparatus 1 is a grinding apparatus for grinding and thinning the workpiece 80, the processing unit 6 is, for example, a grinding means including a grinding wheel rotatable by a spindle connected to a motor as disclosed in Patent Document 2, and the lower surface of the processing unit as the grinding means is the lower surface of the grinding wheel that contacts while applying a load to the upper surface 801 that becomes the surface to be ground of the workpiece 80.

[0026] The processing unit 6 is supported by a support base 50 shown in FIGS. 1 and 2. The support base 50 has, for example, an outer shape formed in a substantially equilateral triangle shape in plan view, and supports the processing unit 6 in the central region of its lower surface via an annular plate-shaped unit coupler 66 shown in FIGS. 2 and 4 and fixing bolts (not shown).

[0027] As shown in FIG. 1, for example, counterbalances 55 are connected to the regions on the vertex side of the support base 50 respectively. The counterbalance 55 is a mechanism for reducing and offsetting the large load due to the self-weights of the processing unit 6 and the support base 50 applied to the vertical movement mechanism 4.

[0028] The counterbalance 55 will be specifically described with reference to FIGS. 2 and 4. The counterbalance 55 is composed of, for example, an air cylinder, and includes a bottomed cylindrical cylinder case 550, a piston (not shown) disposed inside the cylinder case 550 and sliding in the Z-axis direction, and a piston rod 552 inserted into the cylinder case 550 and having an upper end attached to the piston (not shown).

[0029] A lifting block 553 is formed on the lower end side of each piston rod 552. The lower surface of the support base 50 abuts on the upper surface of the lifting block 553 protruding downward from the support base 50, and the lower surface is supported by the lifting block 553 so as to be lifted. Also, the upper end side of the cylinder case 550 is fixed to the upper base 53 shown in FIGS. 1 and 2 described later. An air supply port (not shown) is formed in the side wall of the cylinder case 550, and each air supply port (not shown) communicates with an air supply source composed of a compressor or the like. By adjusting the pressure of the air supplied by the air supply source into the cylinder case 550, it is possible to continuously adjust the force for lifting the support base 50 and the processing unit 6 by the counterbalance 55.

[0030] <H As shown in FIGS. 1 and 2, an upper base 53 is disposed above the support base 50 so as to sandwich the support base 50 from above and below with the lower base 32. The outer shape of the upper base 53 is formed, for example, in a substantially equilateral triangle shape similar to the support base 50 in plan view, and supports the counterbalance 55 in the three vertex-side regions. Note that the centers of the lower base 32, the upper surface 3000 of the table 30, the lower surface 601 of the processing unit 6, the support base 50, and the upper base 53 coincide.

[0031] The processing device 1 is arranged at each vertex of a virtual equilateral triangle formed in the horizontal direction (X-axis and Y-axis directions) with the center of gravity of the processing unit 6 as the center, connects the lower base 32 and the upper base 53, and has three vertical movement mechanisms 4 that move the support base 50 in the vertical direction (Z-axis direction) between the upper base 53 and the lower base 32 to move the processing unit 6 vertically with respect to the upper surface 3000 of the table 30.

[0032] The vertical movement mechanism 4 shown in FIGS. 1, 2, and 4 includes a nut 40 arranged on the support base 50, a ball screw 41 screwed into the nut 40 and extending in the vertical direction, a motor 42 connected to the ball screw 41 to rotate the ball screw 41, a guide rail 44 arranged in parallel with the ball screw 41 to guide the vertical movement of the support base 50 in the Z-axis direction, and a scale for measuring the height of the nut 40 based on the upper surface 3000 of the table 30.

[0033] Each nut 40 is connected, for example, to the outer surface on the vertex side of the support base 50 having a substantially equilateral triangular shape by bolts or the like (not shown). The upper end side of the ball screw 41 into which the nut 40 is screwed and extends in the Z-axis direction is connected to the motor 42 via a fixed-side bearing 420 or a coupling (not shown), and the ball screw 41 is rotatable. The fixed-side bearing 420 is fixed to the lower surface of the upper base 53. Also, the lower end side of the ball screw 41 is supported by a support-side bearing 416, and the support-side bearing 416 is fixed to the upper surface of the lower base 32.

[0034] For example, each guide rail 44 extending in the Z-axis direction at a position closer to the center of the support base 50 than each ball screw 41 has its upper end side fixed to the upper base 53 by a guide rail fixing nut 442. Also, each guide rail 44 passes through an insertion hole provided on each vertex side of the support base 50, and its lower end is fixed to the lower base 32 by a guide rail fixing nut 445.

[0035] In the present embodiment, the first scale 451, the second scale 452, and the third scale 453, which are scales extending in the Z-axis direction along each ball screw 41, are removably fixed, for example, with their upper ends fixed to the side surfaces of the fixed-side bearings 420 and their lower ends fixed to the upper surfaces of the support-side bearings 416. For example, the graduations of the first scale 451 to the third scale 453 are set to 0 μm with reference to the upper surface 3000 of the glass stage 300 of the table 30. The graduations of the first scale 451, the second scale 452, and the third scale 453 are read, for example, by first reading units 456, 457, and 458 such as optical sensors fixed to the side surfaces of the nuts 40 and moving together with the respective nuts 40 along the first scale 451, the second scale 452, and the third scale 453. Note that the first scale 451, the second scale 452, and the third scale 453 may be configured such that a light projecting unit and a light receiving unit are arranged side by side on the upper surface of the frame 301 of the table 30 or the upper surface of the lower base 32 to irradiate the lower surface of the support base 50 with measurement light to measure the distance, or may be an optical length measuring sensor in which the light projecting unit and the light receiving unit face each other vertically in the Z-axis direction, or may be a capacitance displacement sensor, an ultrasonic displacement sensor, or the like.

[0036] The processing apparatus 1 includes control means 9 for controlling at least three vertical movement mechanisms 4 respectively. The control means 9 includes a CPU that performs arithmetic processing according to various control programs and a storage medium such as a memory, and is electrically connected, for example, to the motor 42 of the vertical movement mechanism 4 via wiring. Also, the measurement information from the first reading unit 456 to the third reading unit 458 is received via a wired or wireless communication path.

[0037] [[ID=I1]] The control means 9 is composed of, for example, a microcomputer and a motor driver, etc., and includes a rotation control unit 91 that supplies a predetermined amount of operation signal to rotate the motor 42 to move the nut 40, a setting unit 92 that sets the moving distance of the nut 40 by the rotation control unit 91, and a measurement unit that measures the heights of the nuts 40 arranged on the support base 50 that are rotated and moved by the respective ball screws 41 under the control of the rotation control unit 91 using the first scale 451, the second scale 452, and the third scale 453. A correction unit 94 calculates a correction rotation angle of the motor 42 so that the measured height matches the set height of the nut 40 theoretically predicted when the nut 40 is moved by the moving distance set by the setting unit 92, and further moves the nut 40 by a correction value (correction distance) corresponding to the correction rotation angle. Note that the correction unit 94 may be a storage medium that stores correction values. And the control means 9 may be provided with storage means for storing the correction value in the correction unit 94. Further, after storing the correction value, the first scale 451, the second scale 452, and the third scale 453 become unnecessary. That is, the scale may be mounted only when storing the correction value in the correction unit 94 which is a storage medium.

[0038] Hereinafter, the operation of the processing apparatus 1 when forming a protective member on the workpiece 80 shown in FIGS. 1 and 2 using the above-described processing apparatus 1 will be described. [[ID=~]] First, as shown in FIG. 2, the processing unit 6 sucks and holds the upper surface 801 of the workpiece 80 so that the center of the lower surface 601 substantially coincides with the center of the workpiece 80.

[0039] In parallel with the suction and holding of the workpiece 80 by the processing unit 6, the sheet 82 is placed on the upper surface 3000 of the table 30. Further, a predetermined amount of the liquid resin 89 whose temperature is controlled to the reference temperature is stored in the center of the sheet 82.

[0040] In this embodiment, the setting unit 92 is set in an area of the storage medium of the control means 9. For example, when an operator inputs a desired moving distance of the nut 40 (e.g., the moving distance L1) due to the rotation of the motor 42 of the rotation control unit 91 into an input means (not shown) of the processing apparatus 1, the moving distance L1 is set (stored) in the setting unit 92. The desired moving distance L1 is a moving distance for forming a film of a liquid resin with a desired uniform thickness on the lower surface 800 of the workpiece 80 sucked and held on the lower surface 601 of the processing unit 6 that descends together with the descent of the nut 40. The moving distance L1 of the nut 40 is also the moving distance L1 of the processing unit 6 and the support base 50.

[0041] Next, when an operation signal is supplied from the rotation control unit 91 to each of the motors 42 of the three vertical movement mechanisms 4 and the motor 42 rotates the ball screw 41 in the normal direction at a predetermined rotation speed, the rotational movement of the ball screw 41 is converted into a linear movement in the Z-axis direction of the nut 40 screwed onto the ball screw 41. Along with this, for example, the support base 50 and the processing unit 6 that holds the workpiece 80, which are connected to each nut 40 positioned at the highest position on the ball screw 41, are guided by the three guide rails 44 and descend in the -Z direction. Note that the position where the nut 40 starts to descend is not limited to the highest position on the ball screw 41 as long as it is a position recognized in advance by the control means 9. At this stage, since no load from the table 30 is applied to the processing unit 6, the processing unit 6 is not tilted, and the lower surface 601 parallel to the horizontal plane and the upper surface 3000 of the table 30 are parallel.

[0042] In parallel with the start of the lowering of the support base 50 and the processing unit 6, a force (lifting force) for biasing the support base 50 in the +Z direction is applied by three counterbalances 55. That is, air having a pressure that can generate a force sufficient to cancel out the self-weights of the support base 50 and the processing unit 6, for example, is supplied into the cylinder case 550 from an air supply source (not shown). Since a piston (not shown) in the cylinder case 550 attempts to rise in the +Z direction by the air supplied into the cylinder case 550, a predetermined force for attempting to lift the support base 50 in the +Z direction is applied to the support base 50.

[0043] In this state, the support base 50 and the processing unit 6 descend, and the lower surface 800 of the workpiece 80 held by suction on the processing unit 6 contacts, for example, the liquid resin 89 pooled on the water droplet at the center of the sheet 82. When the processing unit 6 further descends, the liquid resin 89 pressed downward by the lower surface 800 of the workpiece 80 is spread in the radial direction of the lower surface 800 of the workpiece 80. As a result, as shown in FIG. 5, a film of the liquid resin 89 is formed on the lower surface 800 of the workpiece 80.

[0044] Then, after the rotation control unit 91 performs rotation angle control of the motor 42 to supply a predetermined supply amount of an operation signal (for example, a pulse signal) for lowering each nut 40 by a moving distance L1 preset in the setting unit 92 to the motor 42, the lowering of the nut 40, the processing unit 6, and the support base 50 is stopped, and in this state, the spreading of the film of the liquid resin 89 against the lower surface 800 of the workpiece 80 is continued.

[0045] Due to individual differences in the pitch intervals of the ball screws 41 of the three vertical movement mechanisms 4, when the nuts 40 do not move down the same distance L1 even though an operating signal for a predetermined supply amount is supplied to each motor 42, the processing unit 6 tilts. Since this tilt of the processing unit 6 prevents the formation of a protective member made of liquid resin 89 or the like with a uniform thickness on the underside 800 of the workpiece 80, the control means 9 of the processing device 1 according to the present invention performs the control described below.

[0046] First, under the control of the three motors 42 by the rotation control unit 91, the three ball screws 41 are rotated to lower the support base 50, and the height of each nut 40 placed on the support base 50 is measured by the first reading unit 456 to the third reading unit 458, reading the scales of the first scale 451 to the third scale 453, with the top surface 3000 of the table 30, which is a horizontal plane, set as 0 μm, and the measurement information is transmitted to the control means 9.

[0047] For example, in this embodiment, the set height of each nut 40 when the three nuts 40 are moved by the movement distance L1 set in the setting section 92 is a height that is theoretically recognized in advance by the control means 9, and is the height of the nut 40 when it is assumed that no load is applied to the processing unit 6 from the table 30 and the nut 40 is lowered by the rotation control of the motor 42, and is, for example, 750 μm.

[0048] For example, consider a case where the measured value of the third scale 453 shown in FIG. 5 sent to the control means 9 is 775 μm, and the measured values of the first scale 451 and the second scale 452 are 750 μm. In this case, due to factors such as the load applied to the processing unit 6 from the table 30, or the individual difference in the pitch intervals between the ball screw 41 on the first scale 451 side, the ball screw 41 on the second scale 452 side, and the ball screw 41 on the third scale 453 side, the nut 40 on the third scale 453 side has a downward displacement that is 25 μm less than the other two nuts 40, and there is a possibility that the processing unit 6 and the support base 50 will tilt such that the portion on the third scale 453 side (the +X direction side portion, which is the back side of the paper in FIG. 1) is higher than the others.

[0049] Therefore, in the present embodiment, the correction unit 94 integrated with the rotation control unit 91 corrects the rotation angle of the motor 42 on the third scale 453 side so that only the nut 40 on the third scale 453 side further descends by 25 μm in the -Z direction. That is, in the present embodiment, the correction unit 94 calculates the correction rotation angle of the corresponding motor 42 required for the nut 40 on the third scale 453 side to further descend by 25 μm, and the rotation control unit 91 rotates the corresponding motor 42 by the calculated correction rotation angle, and the nut 40 on the third scale 453 side is further lowered by the correction value 25 μm corresponding to the correction rotation angle, so that the nut 40 on the third scale 453 side is positioned at the set height of 750 μm when it is moved by the moving distance L1 set in the setting unit 92. In addition, when the correction unit 94 serves as a storage medium and the correction value of 25 μm obtained by preliminary test machining is stored in the correction unit 94, without actually measuring the height of the nut 40 by the first scale 451 to the third scale 453, the control means 9 may perform control to make the height of the nut 40 match the set height using the correction value of 25 μm stored in the correction unit 94.

[0050] As a result, the inclination of the processing unit 6 and the support base 50 does not occur, and the lower surface 601 becomes a surface parallel to the horizontal direction. This state is maintained, and the expansion of the liquid resin 89 on the lower surface 800 of the workpiece 80 further proceeds for a predetermined time, and a film of the liquid resin 89 is formed on the entire lower surface 800 of the workpiece 80. The film of the liquid resin 89 is corrected for the lowering distance of the nut 40 under the control of the three vertical movement mechanisms 4 by the control means 9 even when the processing unit 6 receives a load (reaction force from the table 30 side), so that the inclination of the processing unit 6 is corrected and the lower surface 601 becomes a surface parallel to the horizontal direction. That is, since a state where the inclination of the processing unit 6 does not change is formed, the thickness is uniform. In addition, for example, even when the processing unit 6 is a grinding means and the workpiece 80 is subjected to grinding, under the control of the three vertical movement mechanisms 4 by the control means 9, even when the processing unit 6 receives a load (reaction force from the table 30 side), the inclination of the processing unit 6 is corrected by correcting the lowering distance of the nut 40, and the lower surface of the grinding wheel of the processing unit is parallel to the upper surface 801 of the workpiece 80 held by the table. That is, since grinding is performed in a state where the inclination of the processing unit 6 does not change, it is possible to grind the workpiece 80 to a uniform thickness.

[0051] Next, an ultraviolet irradiation lamp (not shown) irradiates ultraviolet rays, which are an external stimulus, toward the film of the liquid resin 89 having a uniform thickness. As a result, the film of the liquid resin 89 hardens and is formed as a protective member having a uniform thickness on the lower surface 800 of the workpiece 80.

[0052] For example, in the graph G1 shown in FIG. 6, the vertical axis represents the set height of the nut 40 when the nut 40 on the third scale 453 side is moved by the moving distance set in the setting unit 92, and the horizontal axis represents the descending time of the nut 40. And the graph G2 in FIG. 6 represents the measured height (actual measured value of the height) of the nut 40 on the third scale 453 side measured by the third scale 453. For example, when the set height of the nut 40 shown in FIG. 5 set in the setting unit 92 is 800 μm, the graph G1 and the graph G2 coincide and the correction value is 0 μm. And when the set height of the nut 40 shown in FIG. 5 set in the setting unit 92 is 750 μm, as described above, the correction value is 25 μm.

[0053] And, for example, the correction unit 94 may calculate the correction value L3 between the correction value 25 μm when the set height of the nut 40 is 750 μm and the correction value 0 μm when the set height of the nut 40 is 800 μm, which is another correction value adjacent to the correction value 25 μm, by linear interpolation (or, curve interpolation).

[0054] It should be noted that the processing apparatus 1 according to the present invention is not limited to this embodiment, and it goes without saying that it may be implemented in various different forms within the scope of its technical idea. Hereinafter, another form of the correction performed by the correction unit 94 will be described.

[0055] For example, as shown in FIGS. 1 and 2, the correction unit 94 may include a plurality of correction data tables 940, correction data tables 941, etc. corresponding to the set height of the nut 40. FIG. 7 shows a state where the processing unit 6 is positioned at the height position closest to the upper surface 3000 of the table 30 in the processing apparatus 1. That is, it shows a state where the lower surface 601 of the processing unit 6 is in contact with the upper surface 3000 of the table 30.

[0056] For example, when an operator inputs, to an input means (not shown) of the processing apparatus 1, a moving distance (for example, a moving distance L6) which is a desired ascending distance of the nut 40 by the rotation control unit 91, the moving distance L6 is set (stored) in the setting unit 92. The desired moving distance L6 is the desired moving distance of the nut 40 and also the desired ascending distance of the processing unit 6 and the support base 50.

[0057] In this state, when an operation signal is supplied from the rotation control unit 91 to each motor 42 of the three vertical movement mechanisms 4 and the motor 42 rotates the ball screw 41 in the reverse direction at a predetermined rotational speed, the support base 50 and the processing unit 6 connected to each nut 40 are guided by the three guide rails 44 and ascend in the +Z direction. Then, under the control of the rotation control unit 91, after rotating the motor 42 by a predetermined angle so as to raise the nut 40 by the moving distance L6 set in the setting unit 92 from the height position where the processing unit 6 is closest to the upper surface 3000 of the table 30, the rotation of the motor 42 is stopped, and accordingly, the ascent of the processing unit 6 and the nut 40 is stopped.

[0058] Then, with the upper surface 3000 of the table 30 which is a horizontal plane being set as 0 μm as a reference, the scales of the first scale 451 to the third scale 453 are read and measured by the first reading unit 456 to the third reading unit 458, and the three pieces of measurement information are transmitted to the control means 9.

[0059] The plurality of correction data tables 940, 941, etc. provided in the correction unit 94 each include a set height which is the height of each nut 40 from the upper surface 3000 of the table 30 for raising the processing unit 6 by the moving distance set in the setting unit 92 from the height position closest to the upper surface 3000 of the table 30, and a correction value for making zero the difference between the measured height, which is the height of each nut 40 from the upper surface 3000 of the table 30 measured by the first scale 451 to the third scale 453 when the motor 42 is rotated by a predetermined angle to raise the nut 40 by the moving distance. For example, the set height and the correction value correspond one-to-one and have different values in the correction data table 940 and the correction data table 941. For example, the set height shown in the correction data table 940 is 750 μm and the correction value is 25 μm. Also, the set height shown in the correction data table 941 is 800 μm and the correction value is 0 μm. Note that when the lower surface 601 of the processing unit 6 comes into contact with the upper surface 3000 of the table 30, the moving distance is set to zero in the setting unit 92.

[0060] For example, consider a case where the measured height of the third scale 453 shown in FIG. 8 sent to the control means 9 is 725 μm, and the measured heights of the first scale 451 and the second scale 452 are the same as the set height of 750 μm. In this case, due to factors such as individual differences in the pitch intervals of the ball screw 41 on the first scale 451 side, the ball screw 41 on the second scale 452 side, and the ball screw 41 on the third scale 453 side, the nut 40 on the third scale 453 side has a lift amount 25 μm less than the other two nuts 40. Therefore, the correction unit 94 selects the correction value of 25 μm shown in the correction data table 940 and determines that the correction value for making zero the difference between the measured height of 725 μm, which is the height of the nut 40 on the third scale 453 side from the upper surface 3000 of the table 30 measured by the third scale 453, and the set height of 750 μm is 25 μm.

[0061] In this embodiment, the correction unit 94 integrated with the rotation control unit 91 corrects the rotation angle of the motor 42 on the third scale 453 side so that only the nut 40 on the third scale 453 side is raised by an additional 25 μm. That is, in this embodiment, the correction unit 94 calculates the corrected rotation angle of the corresponding motor 42 required to lower the nut 40 on the third scale 453 side by an additional 25 μm, and the rotation control unit 91 rotates the corresponding motor 42 by the calculated rotation angle to raise the nut 40 on the third scale 453 side by 25 μm, thereby eliminating the tilt of the machining unit 6 and the support base 50. [Explanation of symbols]

[0062] 80: Workpiece 800: Bottom surface of workpiece 801: Top surface of workpiece 1: Processing equipment 30: Table 300: Glass stage 3000: Table top surface 301: Frame 31: Table base 32: Lower base 320: Opening 323: Placement section 6: Processing unit 60: Wheel 601: Underside of processing unit 61: Load sensor 66: Unit connector 50: Support base 55: Counterbalance 550: Cylinder case 552: Piston rod 553: Lifting block 53: Upper base 4: Vertical movement mechanism 40: Nut 41: Ball screw 416: Support side bearing 42: Motor 420: Fixed side bearing 44: Guide rail 451~453: 1st scale~3rd scale 456-458: First reading unit to third reading unit 9: Control means 91: Rotation control section 92: Setting section 94: Correction section

Claims

【Claim 1】 A processing apparatus comprising a table for holding a workpiece on an upper surface thereof, and a processing unit having a lower surface facing the upper surface of the table, wherein a load is applied to the workpiece between the upper surface of the table and the lower surface of the processing unit to grind the workpiece with a grinding wheel or to supply a liquid resin to one surface side of the workpiece under a load and spread the liquid resin on the one surface to cure the liquid resin to form a protective member for protecting the one surface. The processing apparatus further comprises: a lower base for supporting the table from below; a support base for supporting the processing unit from above; an upper base disposed opposite to the lower base so as to sandwich the support base between the lower base; three vertical movement mechanisms disposed at the vertices of a triangle formed horizontally about the center of gravity of the processing unit for vertically moving the support base between the upper base and the lower base; and control means for controlling each of the three vertical movement mechanisms. The vertical movement mechanism comprises: a nut disposed on the support base; a ball screw screwed into the nut and extending in the vertical direction; a fixed-side bearing fixed to the lower surface of the upper base and connected to the upper end side of the ball screw; a support-side bearing fixed to the upper surface of the lower base and supporting the lower end side of the ball screw; a motor connected to the upper end side of the ball screw via the fixed-side bearing for rotating the ball screw; a guide rail disposed in parallel with the ball screw for guiding the vertical movement of the support base; a scale having an upper end side removably fixed to a side surface of the fixed-side bearing and a lower end side removably fixed to the upper surface of the support-side bearing for measuring the height of the nut with reference to the upper surface of the table; and a counterbalance for connecting the upper base and the support base to reduce and offset the self-weights of the processing unit and the support base. The counterbalance, the guide rail, and the ball screw are arranged outward from the center side of the triangle in this order. The control means comprises: a rotation control unit for rotating the motor; a setting unit for setting a moving distance of the nut by the rotation control unit; and a correction unit for calculating a correction rotation angle of the motor so that a measured height measured by the scale of the height of the nut that has moved by rotating the ball screw under the control of the motor by the rotation control unit matches a set height of the nut when the nut is moved by the moving distance set by the setting unit, and further moving the nut by an amount corresponding to a correction value corresponding to the correction rotation angle. A processing apparatus.

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