JP2010186863A - Aligning mechanism, working device and aligning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligning mechanism capable of accurately aligning a semiconductor wafer containing warpages, to a chuck table without damage, and to provide a working device and an alignment method. <P>SOLUTION: The aligning mechanism includes a temporary positioning table 23 being formed in a diameter larger than the outside diameter of the semiconductor wafer and including a suction surface 25, sucking at least the outer periphery of the semiconductor wafer: an imaging mechanism 24 imaging the outer periphery of the semiconductor wafer sucked to the suction surface 25; and a controller computing the positional data of the center of the semiconductor wafer, on the basis of the image data of the outer periphery of the semiconductor wafer. The aligning mechanism, further, includes a wafer supply 17 placing the semiconductor wafer on a holding surface 56, in a state of aligning the center of the semiconductor wafer at the center of the holding surface 56 of the chuck table 52 holding the semiconductor wafer, on the basis of the positional data of the center of the semiconductor wafer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alignment mechanism, a processing apparatus, and an alignment method for adjusting the position of a semiconductor wafer when the semiconductor wafer is ground and polished.

  Conventionally, as an alignment mechanism for aligning a semiconductor wafer with respect to a chuck table of a grinding apparatus, one that positions the center of a semiconductor wafer at the center of a temporary placement table and then transfers the semiconductor wafer to the chuck table (for example, , See Patent Document 1). This conventional alignment mechanism includes a temporary placement table having a smaller diameter than that of a semiconductor wafer, a plurality of pins movable in the radial direction around the temporary placement table, and a position after positioning on the temporary placement table. And a transfer unit that transfers the semiconductor wafer onto the chuck table.

  In this alignment mechanism, when the semiconductor wafer is placed on the temporary placement table, the plurality of pins move toward the center of the temporary placement table and abut against the outer peripheral surface of the semiconductor wafer. Positioned at the center of the temporary table. Then, the semiconductor wafer after positioning is sucked and held by the transfer unit, and is placed on the upper surface of the chuck table by the rotation of the transfer unit. At this time, since the center of the temporary placement table and the center of the chuck table are located on the turning locus of the transfer unit, the center of the transferred semiconductor wafer is aligned with the center of the chuck table.

JP 2003-133392 A

  However, in the above-described conventional alignment mechanism, when the semiconductor wafer includes a warp, when the plurality of pins hit the outer peripheral surface of the semiconductor wafer, the temporary placement table is displaced by the amount of the warp of the semiconductor wafer. Is positioned. Therefore, when the semiconductor wafer is transferred to the chuck table, there is a problem that the center of the semiconductor wafer cannot be accurately aligned with the center of the chuck table. In particular, many thin semiconductor wafers contain warpage and cannot be accurately aligned, and may be damaged when the pins are abutted.

  The present invention has been made in view of the above points, and provides an alignment mechanism, a processing apparatus, and an alignment method capable of accurately aligning with a chuck table without damaging a semiconductor wafer including warpage. For the purpose.

  The alignment mechanism of the present invention includes a workpiece support base that is formed to have a larger diameter than the outer diameter of the workpiece and has an adsorption surface that adsorbs at least an outer peripheral edge portion of the workpiece, A position data acquisition unit that acquires position data of a peripheral part; a position data calculation part that calculates position data of the center of the work based on position data of an outer peripheral part of the work; and position data of the center of the work And an alignment portion for placing the workpiece on the holding surface in a state where the center of the workpiece is aligned with the center of the holding surface of the holding table on which the workpiece is held. And

  The positioning method of the present invention includes a step of placing the workpiece on a workpiece support base that is formed to have a larger diameter than the outer diameter of the workpiece and has a suction surface that sucks at least the outer peripheral edge of the workpiece; Obtaining the position data of the outer peripheral edge of the work adsorbed on a table, calculating the position data of the center of the work indicating the center of the work based on the position data of the outer peripheral edge of the work; Placing the workpiece on the holding surface in a state where the center of the workpiece is aligned with the center of the holding surface of the holding table on which the workpiece is held based on the position data of the center of the workpiece; It is characterized by having.

  According to these configurations, even when the workpiece includes warpage, at least the outer peripheral edge portion of the workpiece is attracted to the suction surface, and the warpage of the workpiece is corrected. Therefore, since the position data of the outer peripheral edge is acquired in a state where the warp of the workpiece is corrected, the position data of the center of the workpiece can be accurately calculated, and the center of the workpiece is accurately positioned with respect to the center of the holding table. Can be combined. In addition, positioning by abutment of a plurality of pins on the workpiece support table is not necessary, and damage during alignment of a thin workpiece can be prevented.

  According to the present invention, in the above alignment mechanism, a mark portion indicating the orientation of the workpiece is formed on the outer peripheral edge portion of the workpiece, and the position data calculating portion is a position data of the outer peripheral edge portion of the workpiece. The position data of the center of the workpiece is calculated based on the angle, the angle data indicating the orientation of the workpiece is calculated based on the mark portion, and the alignment unit is configured to calculate the position data of the center of the workpiece and the angle Based on the data, the center of the workpiece is aligned with the center of the holding surface, and the orientation of the workpiece is aligned with the orientation of the chuck table.

  Further, the present invention provides the alignment mechanism, wherein the work support has a light transmitting portion that transmits at least light applied to the outer peripheral edge of the work, and is about an axis orthogonal to the suction surface. The position data acquisition unit is configured to be rotatable, and includes an irradiation unit that irradiates an outer peripheral edge of the work, and an imaging unit that reads transmitted light that has passed through the work through the light transmission unit. An imaging mechanism that acquires image data of the outer peripheral edge of the workpiece is configured.

  The processing apparatus of the present invention includes the above-described alignment mechanism and a processing mechanism that processes the workpiece in a state where the center of the workpiece is aligned with the center of the holding table.

  According to the present invention, the semiconductor wafer including warpage can be accurately aligned with the chuck table without damaging the semiconductor wafer.

It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is an external appearance perspective view of a grinding device. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is the elements on larger scale of a grinding device. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is explanatory drawing of the imaging process of a semiconductor wafer. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is a figure which shows the image data imaged by the imaging part. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is a figure which shows the center coordinate of the semiconductor wafer containing curvature. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is explanatory drawing of position alignment of the semiconductor wafer with respect to a chuck table. It is a figure which shows embodiment of the position alignment mechanism based on this invention, and is the whole operation | movement flow of the position alignment process by a processing apparatus. It is a figure which shows the modification of the position alignment mechanism which concerns on this invention. It is a figure which shows embodiment of the position alignment mechanism which concerns on this invention, and is an external appearance perspective view of a semiconductor wafer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The alignment mechanism according to the present embodiment accurately aligns the semiconductor wafer with the chuck table by correcting the warp of the semiconductor wafer and accurately calculating the center of the semiconductor wafer. First, before describing the alignment mechanism according to the embodiment of the present invention, a semiconductor wafer to be processed will be briefly described. FIG. 9 is an external perspective view of the semiconductor wafer according to the embodiment of the present invention. Note that FIG. 9 shows a state in which the back surface of the semiconductor wafer is directed upward.

  As shown in FIG. 9, the semiconductor wafer W is formed in a substantially disc shape, and is partitioned into a plurality of regions by unscheduled division lines (not shown) arranged on the surface in a lattice shape. A device 81 such as an IC or LSI is formed in the center of the semiconductor wafer W in each region partitioned by the division lines. Further, a notch 82 indicating a crystal orientation is formed on the outer peripheral edge of the semiconductor wafer W. A protective tape 83 is attached to the surface of the semiconductor wafer W, and the device 81 is protected by the protective tape 83 when the back surface of the semiconductor wafer W is processed. The semiconductor wafer W configured in this way is carried into the grinding apparatus 1 while being accommodated in the carry-in cassette 2 (see FIG. 1).

  In the present embodiment, a semiconductor wafer W such as a silicon wafer or GaAs will be described as an example of the workpiece. However, the present invention is not limited to this configuration, and ceramic, glass, sapphire inorganic substrate, The workpiece may be a plate metal or resin ductile material, or various processed materials that require a micron order flatness on the order of submicrons.

  Next, an example in which the alignment mechanism according to the embodiment of the present invention is applied to a grinding apparatus will be described with reference to FIGS. FIG. 1 is an external perspective view of a grinding apparatus according to an embodiment of the present invention. FIG. 2 is a partially enlarged view of the grinding apparatus according to the embodiment of the present invention. In the following description, an example in which the alignment mechanism is applied to a grinding apparatus will be described. However, the present invention can be applied not only to a grinding apparatus but also to a processing apparatus that aligns the center of a semiconductor wafer with the center of a chuck table. It is.

  As shown in FIG. 1, the grinding apparatus 1 carries in a semiconductor wafer W before processing, a loading / unloading unit 4 for unloading the processed semiconductor wafer W, and a semiconductor wafer W loaded from the loading / unloading unit 4. It comprises a wafer processing unit 5 for grinding the back surface. The carry-in / carry-out unit 4 has a rectangular parallelepiped base 11, and the base 11 is provided with a pair of cassette placement portions 12 and 13 on which the cassettes 2 and 3 are placed so as to protrude forward from the front surface 11a. It has been.

  The cassette mounting portion 12 functions as a carry-in entrance, and the carry-in cassette 2 in which the semiconductor wafer W before processing is accommodated is placed. The cassette mounting portion 13 functions as a carry-out port, and the carry-out cassette 3 in which the processed semiconductor wafer W is accommodated is placed. On the upper surface of the base 11, a loading / unloading arm 14 is provided so as to face the cassette mounting portions 12 and 13, and the temporary placing portion 15 is adjacent to the loading / unloading arm 14 at one corner on the wafer processing unit 5 side. Spinner cleaning units 16 are provided at the other corners. In addition, on the upper surface of the base 11, a wafer supply unit 17 and a wafer recovery unit 18 are provided between the temporary placement unit 15 and the spinner cleaning unit 16. Furthermore, a control unit 19 that performs overall control of the loading / unloading unit 4 is provided inside the base 11.

  The carry-in / carry-out arm 14 includes a multi-node link mechanism 21 having a wide driving area, and a suction holding unit 22 that is provided at the tip of the multi-node link mechanism 21 and holds the semiconductor wafer W by suction. The carry-in / carry-out arm 14 drives the multi-joint link mechanism 21 to place the semiconductor wafer W accommodated in the carry-in cassette 2 on the temporary placement unit 15 and from the spinner cleaning unit 16 into the carry-out cassette 3. The semiconductor wafer W is accommodated in

  As illustrated in FIG. 2, the temporary placement unit 15 includes a temporary placement table 23 on which the semiconductor wafer W is temporarily placed by the loading / unloading arm 14, and an imaging mechanism 24 that images the semiconductor wafer W temporarily placed on the temporary placement table 23. It consists of and. The temporary placement table 23 is formed in a disc shape with a light-transmitting material such as glass and has a larger diameter than the semiconductor wafer W. On the upper surface of the temporary placement table 23, a suction surface 25 for sucking the semiconductor wafer W is formed.

  On the suction surface 25, a plurality of annular grooves 25a arranged concentrically, a plurality of linear grooves 25b extending radially from the center of the suction surface 25, and intersections of the plurality of annular grooves 25a and the plurality of linear grooves 25b A plurality of suction holes (not shown) arranged in the are formed. The plurality of suction holes penetrate the temporary table 23 and are connected to a suction source (not shown), and the semiconductor wafer W is sucked to the suction surface 25 by suction of the suction source.

  Specifically, negative pressure is generated in the plurality of annular grooves 25a and the plurality of linear grooves 25b through the plurality of suction holes by suction of the suction source, and the semiconductor wafer W is attracted to the suction surface 25 by this negative pressure, The plurality of annular grooves 25a and the plurality of linear grooves 25b are sealed. At this time, since the suction surface 25 has a larger diameter than the semiconductor wafer W, the annular groove 25a and a part of the linear groove 25b are opened to the atmosphere. However, the suction is not problematic in correcting the warpage of the semiconductor wafer W. Have power. With such a groove configuration formed on the suction surface 25, the temporary placement table 23 can be used for general purposes on semiconductor wafers having different diameters.

  The temporary placement table 23 is connected to a rotation drive mechanism (not shown) and is configured to be rotatable by driving the rotation drive mechanism. The imaging position in the circumferential direction of the semiconductor wafer W is adjusted by driving the rotation driving mechanism.

  The imaging mechanism 24 includes an irradiation unit 27 that irradiates the semiconductor wafer W from the lower side of the temporary placement table 23, and an imaging unit 28 that reads transmitted light transmitted through the semiconductor wafer W above the temporary placement table 23. . The irradiation unit 27 is disposed below the temporary placement table 23 and is located on the radially outer side of the temporary placement table 23. The imaging unit 28 is provided above the temporary placement table 23 via the support member 29, and is configured to be movable in the radial direction of the temporary placement table 23. The movement of the imaging unit 28 adjusts the imaging position in the radial direction of the semiconductor wafer W.

  The position of the semiconductor wafer W temporarily placed on the temporary placement table 23 is adjusted so that a part of the outer peripheral edge is included in the imaging range, and is imaged by the imaging mechanism 24. This imaging operation is performed until the outer peripheral edge is imaged over the entire circumference of the semiconductor wafer W by the imaging mechanism 24, and the image data captured by the imaging mechanism 24 is output to the control unit 19.

  The wafer supply unit 17 is provided with a pivot shaft 31 extending in the vertical direction, an extendable arm 32 supported on the upper end of the pivot shaft 31, and a suction for holding the semiconductor wafer W by suction. Holding part 33. The rotation shaft 31 is configured to be movable up and down, back and forth, and rotatable, and the extendable arm 32 is configured to be extendable and contractable in the extending direction. The suction holding portion 33 is adjusted in position in the horizontal plane by the forward / backward movement and rotation of the rotation shaft 31 and the expansion / contraction of the telescopic arm 32, and is adjusted in the height direction by the vertical movement of the rotation shaft 31.

  The wafer supply unit 17 is driven and controlled by the control unit 19, and the control unit 19 adjusts the vertical movement amount, the front-rear movement amount, the rotation amount, and the expansion / contraction amount of the telescopic arm 32. Is done. Then, the wafer supply unit 17 is controlled by the control unit 19, sucks and holds the semiconductor wafer W from the temporary placement table 23, and supplies it to the chuck table 52. At this time, the center of the semiconductor wafer W is aligned with the center of the holding surface 56 of the chuck table 52 of the wafer processing unit 5, and the semiconductor wafer W is aligned with the direction of the chuck table 52.

  The wafer collection unit 18 has substantially the same configuration as the wafer supply unit 17 except that the suction holding unit 37 is formed to have a larger diameter than the suction holding unit 33 of the wafer supply unit 17. The wafer recovery unit 18 is controlled by the control unit 19 to suck and hold the semiconductor wafer W from the chuck table 52 and recover it, and places it on the spinner cleaning table 41 of the spinner cleaning unit 16. At this time, the center of the semiconductor wafer W is aligned with the center of the mounting surface 42 of the spinner cleaning table 41 of the spinner cleaning unit 16 and the orientation of the semiconductor wafer W is aligned with the direction of the spinner cleaning table 41. The

  Returning to FIG. 1, the spinner cleaning unit 16 has a spinner cleaning table 41 on which the processed semiconductor wafer W is placed. The spinner cleaning table 41 has a disk shape and has a mounting surface 42 on which the semiconductor wafer W is mounted. An adsorption surface 42 a is formed of a porous ceramic material at the center portion of the mounting surface 42. The suction surface 42 a is formed according to the outer shape of the semiconductor wafer W in plan view, and is formed in a circular shape except for a portion corresponding to the notch 82 of the semiconductor wafer W. The direction of the spinner cleaning table 41 is defined by the direction of the portion corresponding to the notch 82 of the semiconductor wafer W. The suction surface 42a is connected to a suction source (not shown) disposed in the base 11 and holds the semiconductor wafer W by suction.

  When the processed semiconductor wafer W is placed on the spinner cleaning table 41, the semiconductor wafer W is accommodated in the base 11 through the opening 43 by the lowering of the spinner cleaning table 41. The semiconductor wafer W accommodated in the base 11 is cleaned by being sprayed with cleaning water while being rotated at a high speed. Thereafter, the jet of cleaning water is stopped in a state where the semiconductor wafer W is rotated at a high speed, and the semiconductor wafer W is dried.

  The control unit 19 performs imaging processing of the semiconductor wafer W by the imaging mechanism 24, calculation processing of position data indicating the center of the semiconductor wafer W and angle data indicating the orientation of the semiconductor wafer W, and the semiconductor wafer for the chuck table 52 and the spinner cleaning table 41. Each process such as the W alignment process is executed. Further, the control unit 19 stores an orthogonal plane coordinate system (see FIG. 6) used for the alignment process together with a control program for each process.

  In addition, the control part 19 calculates the data in RAM (Random Access Memory) according to various programs, such as a control program in ROM (Read Only Memory), and CPU (Central Processing Unit) incorporated in the inside, and the carrying in / out unit 4 Each process is executed in cooperation with each part. Details of the calculation processing of the position data indicating the center of the semiconductor wafer W and the angle data indicating the direction of the semiconductor wafer W and the alignment processing of the semiconductor wafer W with respect to the chuck table 52 and the spinner cleaning table 41 will be described later.

  The wafer processing unit 5 is configured to process the semiconductor wafer W by relatively rotating the rough grinding unit 45 and the finish grinding unit 46 and the chuck table 52 holding the semiconductor wafer W. The wafer processing unit 5 has a rectangular parallelepiped base 51, and the loading / unloading unit 4 is connected to the front surface of the base 51. A turntable 53 on which three chuck tables 52 are arranged is provided on the upper surface of the base 51, and a column portion 54 is erected on the rear side of the turntable 53.

  The turntable 53 is formed in a large-diameter disk shape, and three chuck tables 52 are arranged on the upper surface at intervals of 120 degrees in the circumferential direction. The turntable 53 is connected to a rotation drive mechanism (not shown), and is intermittently rotated at intervals of 120 degrees in the D1 direction by the rotation drive mechanism. As a result, the three chuck tables 52 are provided at a transfer position where the semiconductor wafer W is transferred between the wafer supply unit 17 and the wafer recovery unit 18, a rough grinding position where the semiconductor wafer W is opposed to the rough grinding unit 45, and finish grinding. The unit 46 is moved between finish grinding positions where the semiconductor wafer W is opposed to the unit 46.

  The chuck table 52 has a disc shape and has a holding surface 56 on which the semiconductor wafer W is held (see FIG. 2). An adsorption surface 56 a is formed of a porous ceramic material at the central portion of the holding surface 56. The suction surface 56a is formed in accordance with the outer shape of the semiconductor wafer W in plan view, and is formed in a circular shape except for a portion corresponding to the notch 82 of the semiconductor wafer W. The orientation of the chuck table 52 is defined by the orientation of the portion corresponding to the notch 82 of the semiconductor wafer W.

  The chuck table 52 is connected to a suction source (not shown) arranged in the base 51 and holds the semiconductor wafer W by suction. The chuck table 52 is connected to a rotation driving mechanism (not shown), and is rotated while the semiconductor wafer W is held on the holding surface 56 by the rotation driving mechanism.

  On the upper surface of the base 51, a contact sensor 58 is provided in the vicinity of the rough grinding position and the finish grinding position of the turntable 53. The contact sensor 58 has two contacts 61 and 62, one contact 61 being in contact with the upper surface of the semiconductor wafer W, and the other contact 62 being in contact with the upper surface of the chuck table 52. The grinding depth is controlled from the difference in height between the two contactors 61 and 62.

  The support portion 54 is formed in a base shape with a pair of slopes as viewed from above, and grinding unit moving mechanisms 64 and 65 for moving the rough grinding unit 45 and the finish grinding unit 46 above the chuck table 52 on the pair of slopes. Is provided. The grinding unit moving mechanism 64 moves in the R1 direction with respect to the support 54 by a ball screw type moving mechanism, and moves in the vertical direction with respect to the R axis table 67 by means of a ball screw type moving mechanism. And a Z-axis table 71. A rough grinding unit 45 is supported on the Z-axis table 71 via a support portion 75 attached to the front surface. Further, the grinding unit moving mechanism 65 has the same configuration as the grinding unit moving mechanism 64, and the finish grinding unit 46 is supported.

  The rough grinding unit 45 has a grinding wheel 73 that is detachably attached to the lower end of a spindle (not shown). The grinding wheel 73 is constituted by a diamond grinding stone in which diamond abrasive grains are hardened with a binder such as a metal bond or a resin bond. The grinding wheel 73 is formed in a thin cylindrical shape and has a ring-shaped grinding surface. The finish grinding unit 46 has the same configuration as that of the rough grinding unit 45, but a grinding wheel 74 having a fine grain size is used.

  The rough grinding unit 45 is positioned in the radial direction of the grinding wheel 73 with respect to the semiconductor wafer W by the grinding unit moving mechanism 64 and is ground and fed in the Z-axis direction while monitoring the grinding amount by the contact sensor 58. Further, after rough grinding is performed in the rough grinding unit 45, finish grinding is performed in the finish grinding unit 46 by the same operation.

  With reference to FIG. 3, the imaging process of the semiconductor wafer by the imaging mechanism will be described. FIG. 3 is an explanatory diagram of the imaging process of the semiconductor wafer by the imaging mechanism. In the following description, for the convenience of description, it is assumed that the outer peripheral edge portion of the semiconductor wafer includes a warp.

As shown in FIG. 3A, in an initial state where the semiconductor wafer W is not temporarily placed on the temporary placement table 23, the imaging unit 28 is located at a retreat position on the radially outer side of the temporary placement table 23. From this state, as shown in FIG. 3B, the semiconductor wafer W held by the carry-in / carry-out arm 14 is temporarily placed on the upper surface of the temporary placement table 23. At this time, the wafer is temporarily placed in a state in which the warping of the outer peripheral edge of the semiconductor wafer W is corrected by the suction of the suction holding unit 22 of the loading / unloading arm 14. Next, when the loading / unloading arm 14 is retracted from the temporary placement table 23, the semiconductor wafer W is attracted to the suction surface 25 of the temporary placement table 23 as shown in FIG. At this time, the semiconductor wafer is sucked to the suction surface 25 at the same time as or before the suction of the suction holding unit 22 of the loading / unloading arm 14 is released, and the warpage of the outer peripheral edge of the semiconductor wafer W is corrected.

  When the warpage of the outer peripheral edge of the semiconductor wafer W is corrected, the imaging unit 28 moves to an imaging position for imaging the outer peripheral part of the semiconductor wafer W, and as shown in FIG. Are included in the imaging range of the imaging unit 28. Then, as shown in FIG. 3E, the irradiation unit 27 irradiates the semiconductor wafer W from below the temporary placement table 23, and the transmitted light transmitted through the temporary placement table 23 and the semiconductor wafer W is read by the imaging unit 28. It is. When the imaging of the outer peripheral edge of the semiconductor wafer W is completed at one location, the temporary placement table 23 is rotated, and imaging is performed over the entire circumference of the outer peripheral edge of the semiconductor wafer W. The image data captured by the imaging unit 28 is output to the control unit 19. When imaging by the imaging unit 28 is completed, the imaging unit 28 moves to the retracted position and is in an initial state.

  With reference to FIG. 4, the calculation processing of the position data indicating the center of the semiconductor wafer and the angle data indicating the direction of the semiconductor wafer by the control unit will be described. FIG. 4 is a diagram illustrating image data captured by the imaging unit.

  The image data output to the control unit 19 is subjected to edge detection processing by the control unit 19 to obtain a curve indicating the outer peripheral edge of the semiconductor wafer W. When the curve of the outer peripheral edge of the semiconductor wafer W is obtained, the coordinates of points A, B, and C are arbitrarily extracted from the curve of the outer peripheral edge. At this time, the coordinates of three points may be extracted from one image data obtained by one imaging operation, or the coordinates of three points are extracted from a plurality of image data obtained by a plurality of imaging operations. You may do it.

  The intersection of the bisector perpendicular to the line connecting point A and point B and the bisector perpendicular to the line connecting point B and point C is calculated as the center coordinate P1 of the semiconductor wafer W. Is done. When the center coordinate P1 of the semiconductor wafer W is calculated, an angle R formed by the reference axis L1 passing through the center coordinate P1 and the straight line L2 connecting the center coordinate P1 and the center of the notch 82 is calculated. At this time, the reference axis L1 corresponds to a reference direction when the chuck table 52 is transferred to the wafer, and the chuck table 52 is rotated on the chuck table 52 by rotating the chuck table 52 by an angle R from the reference direction. When placed, the orientation of the semiconductor wafer W can be matched with the orientation of the chuck table 52.

  Thus, since the center of the semiconductor wafer W is calculated in a state where the warp of the semiconductor wafer W is corrected in the imaging process, the center of the semiconductor wafer W can be accurately calculated. For example, in FIG. 5, the center coordinate P1 calculated from the image data of the semiconductor wafer W including the warp indicated by the solid line is the center coordinate P2 calculated from the image data of the semiconductor wafer W not including the warp indicated by the alternate long and short dash line. In comparison, a positional deviation occurs.

  In this embodiment, three points are detected after detecting the outer peripheral edge curve of the semiconductor wafer W, but three points are detected directly without detecting the outer peripheral edge curve of the semiconductor wafer W. It is good also as composition to do. Thereby, it is possible to reduce the detection processing amount and improve the calculation speed.

  With reference to FIG. 6, the alignment process of the semiconductor wafer with respect to the chuck table will be described. FIG. 6 is an explanatory diagram of the alignment of the semiconductor wafer with respect to the chuck table. In the initial state, it is assumed that the chuck table faces the positive Y-axis direction.

  As shown in FIG. 6, the control unit 19 has an orthogonal plane coordinate system composed of an X axis and a Y axis. In this orthogonal plane coordinate system, the center coordinates P3 of the chuck table 52 stored in advance are calculated. The center coordinate P1 of the semiconductor wafer W and the angle R indicating the direction of the semiconductor wafer W are set. First, based on the difference between the center coordinate P3 of the chuck table 52 and the center coordinate P1 of the semiconductor wafer W by the control unit 19, the amount of movement and rotation of the rotation axis 31 of the wafer supply unit 17 in the front-rear direction, the extendable arm 32, and so on. And the amount of rotation of the chuck table 52 is calculated based on the angle R indicating the direction of the semiconductor wafer W.

  Next, the wafer supply unit 17 moves upward by moving the rotation shaft 31 downward and sucking and holding the semiconductor wafer W by the suction holding unit 33 from a state of being positioned above the temporary placement table 23. Next, the wafer supply unit 17 drives the rotation shaft 31 according to the movement amount and the rotation amount of the rotation shaft 31 in the front-rear direction calculated by the control unit 19. Next, the wafer supply unit 17 drives the expansion / contraction arm 32 according to the expansion / contraction amount of the expansion / contraction arm 32 calculated by the control unit 19 to position the semiconductor wafer W above the chuck table 52. At this point, the center of the semiconductor wafer W coincides with the center of the holding surface 56 of the chuck table 52.

  Next, the chuck table 52 is rotated by an angle R from the initial state where the chuck table 52 is directed in the positive direction of the Y axis, and the orientation of the chuck table 52 is made to coincide with the orientation of the semiconductor wafer W. Next, the wafer supply unit 17 lowers the rotation shaft 31 to release the suction of the suction holding unit 33. In this manner, the center of the semiconductor wafer W is aligned with the center of the holding surface 56 of the chuck table 52, and the direction of the semiconductor wafer W is aligned with the direction of the chuck table 52. Further, the alignment process of the semiconductor wafer W with respect to the spinner cleaning table 41 is also performed by the same process as the alignment process described above.

  Thus, since the semiconductor wafer W is aligned with the chuck table 52 in a state where the orientation of the semiconductor wafer W is aligned with the orientation of the chuck table 52, the semiconductor wafer W matches the suction surface 56 a of the chuck table 52. Is placed as follows. Accordingly, the notch 82 formed on the semiconductor wafer W and the portion corresponding to the notch 82 in the suction surface 56a coincide with each other, and the suction force of the suction surface 56a is reduced due to the positional deviation between the semiconductor wafer W and the suction surface 56a. Is prevented.

  Next, with reference to FIG. 7, an overall operation flow of alignment by the processing apparatus will be described. FIG. 7 is an overall operation flow of alignment processing by the processing apparatus. The following operation flow is implemented by a control program that causes the machining apparatus to execute steps S01 to S04.

  As shown in FIG. 7, the semiconductor wafer W before processing is taken out from the cassette 2 by the loading / unloading arm 14 and temporarily placed on the temporary placement table 23 (step S01). At this time, the warpage of the outer peripheral edge of the semiconductor wafer W is corrected by the suction surface 25 of the temporary placement table 23. Next, the semiconductor wafer W is imaged by the imaging mechanism 24 with the warpage of the outer peripheral edge of the semiconductor wafer W corrected, and the captured image data is output to the control unit 19 (step S02). Next, based on the image data input by the control unit 19, the central coordinate P1 of the semiconductor wafer W and the angle R indicating the direction of the semiconductor wafer W are calculated (step S03). Next, based on the calculated center coordinate P1 and angle R of the semiconductor wafer W, the orientation of the semiconductor wafer W is aligned with the orientation of the chuck table 52, and the center of the semiconductor wafer W is aligned with the center of the chuck table 52. (Step S04).

  As described above, according to the alignment mechanism according to the present embodiment, even when the semiconductor wafer W includes a warp, at least the outer peripheral edge portion of the semiconductor wafer W is attracted to the suction surface 25 of the temporary placement table 23. Thus, the warp of the semiconductor wafer W is corrected. Therefore, since the image is taken with the warpage of the semiconductor wafer W corrected, the position data of the center of the semiconductor wafer W can be accurately calculated, and the center of the semiconductor wafer W is accurately positioned at the center of the chuck table 52. It becomes possible to match. In addition, positioning by abutment of a plurality of pins in the temporary placement table 23 is not necessary, and it is possible to prevent breakage during alignment of the thin semiconductor wafer W.

  In the above-described embodiment, the suction surface 25 of the temporary placement table 23 is configured to suck the semiconductor wafer W as a whole, but is not limited to this configuration. It is only necessary that the suction surface 25 is formed in a range where the warp of the semiconductor wafer W can be corrected in the temporary placement table 23. For example, the suction surface is formed only at a position where the outer peripheral edge of the semiconductor wafer W can be sucked. It may be configured.

  In the above-described embodiment, the notch 82 is exemplified and described as the mark portion that defines the direction of the semiconductor wafer W. However, the present invention is not limited to this configuration. It is only necessary that the direction of the semiconductor wafer W can be specified at the outer peripheral edge of the semiconductor wafer W, and an orientation flat may be used instead of the notch 82.

  In the above-described embodiment, the entire temporary placement table 23 is formed of a translucent material. However, the present invention is not limited to this configuration. Any structure capable of imaging at least the outer peripheral edge of the semiconductor wafer W placed on the temporary placement table 23 may be used. For example, the outer peripheral edge of the semiconductor wafer W is formed only at a position where it can be imaged with a translucent material. It is good also as composition to do.

  In the above-described embodiment, the temporary table 23 is formed of a light-transmitting material, and the imaging unit 28 reads the transmitted light that has passed through the temporary table 23 and the semiconductor wafer W. It is not limited. Any structure capable of imaging the semiconductor wafer W may be used. For example, as shown in FIG. 8A, a part of the temporary placement table 94 is opened, and the transmitted light transmitted through the semiconductor wafer W through the opening 95 is provided. 8 may be configured to be read by the imaging unit 93, or as illustrated in FIG. 8B, the temporary placement table 96 is mirror-finished and the reflected light reflected by the temporary placement table 96 is read by the imaging unit 97. It is good.

  In the above embodiment, the center of the semiconductor wafer W is aligned with the center of the chuck table 52 and the orientation of the semiconductor wafer W is aligned with the orientation of the chuck table 52. It is good also as a structure which performs only alignment with the center of the chuck table 52. FIG.

  In the above-described embodiment, the center of the semiconductor wafer W is calculated by image processing. However, the present invention is not limited to this configuration. Any configuration capable of detecting the outer peripheral edge of the semiconductor wafer W may be used. For example, the outer peripheral edge of the semiconductor wafer W may be detected using a reflective photosensor.

  In the above-described embodiment, the movement of the wafer supply unit 17 is controlled to align the center of the semiconductor wafer W with the center of the chuck table 52. However, the present invention is not limited to this configuration. Any configuration may be used as long as the center of the semiconductor wafer W is calculated and aligned with the center of the chuck table 52. For example, the alignment may be performed on the temporary placement table 23 or the chuck table 52.

  In the above-described embodiment, the rotation amount of the chuck table 52 is controlled at the time of alignment to adjust the orientation of the semiconductor wafer W and the orientation of the chuck table 52. However, the present invention is not limited to this configuration. . Any configuration is possible as long as the orientation of the semiconductor wafer W and the orientation of the chuck table 52 can be matched. For example, the orientation may be adjusted on the temporary placement table 23 or the wafer supply unit 33 side.

  In the above-described embodiment, the control unit 19 detects the arbitrary three points on the outer peripheral edge of the semiconductor wafer W and calculates the center of the semiconductor wafer W. However, the present invention is limited to this configuration. is not. Any calculation method may be used as long as the center of the semiconductor wafer W can be calculated. For example, it is also possible to detect two points from the curves of the outer peripheral edge obtained from the image data, and to set the intersection of the normals to each curve from these two points as the center of the semiconductor wafer W.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

  As described above, the present invention has an effect that the semiconductor wafer including warpage can be accurately aligned with the chuck table without damaging the semiconductor wafer, and particularly when the semiconductor wafer is ground. This is useful for an alignment mechanism, a processing apparatus, and an alignment method for performing the position adjustment.

1 Grinding equipment (processing equipment)
4 Loading / unloading unit (positioning mechanism)
5 Wafer processing unit (processing mechanism)
14 Loading / unloading arm 15 Temporary placement unit 16 Spinner cleaning unit 17 Wafer supply unit (positioning unit)
18 Wafer recovery unit 19 Control unit (position data calculation unit, alignment unit)
23, 94, 96 Temporary table (work support table)
24 Imaging mechanism (position data acquisition unit)
25 suction surface 25a annular groove 25b linear groove 27 irradiation unit 28, 93, 97 imaging unit 52 chuck table (holding table)
56 Holding surface 82 Notch 94 Opening W Semiconductor wafer

Claims (5)

A work support that is formed to have a larger diameter than the outer diameter of the work and has a suction surface that sucks at least the outer peripheral edge of the work;
A position data acquisition unit for acquiring position data of the outer peripheral edge of the workpiece adsorbed on the adsorption surface;
A position data calculation unit that calculates position data of the center of the workpiece based on position data of the outer peripheral edge of the workpiece;
An alignment unit that places the workpiece on the holding surface in a state in which the center of the workpiece is aligned with the center of the holding surface of the holding table that holds the workpiece based on the position data of the center of the workpiece. And an alignment mechanism characterized by comprising: The outer peripheral edge of the work is formed with a mark indicating the orientation of the work,
The position data calculation unit calculates the position data of the center of the workpiece based on the position data of the outer peripheral edge of the workpiece, and calculates angle data indicating the orientation of the workpiece based on the mark,
The alignment unit aligns the center of the workpiece with respect to the center of the holding surface based on the position data of the center of the workpiece and the angle data, and sets the orientation of the workpiece with respect to the orientation of the chuck table. The alignment mechanism according to claim 1, wherein the alignment mechanism is aligned. The work support has at least a light-transmitting part that transmits light applied to the outer peripheral edge of the work, and is configured to be rotatable about an axis orthogonal to the adsorption surface.
The position data acquisition unit includes an irradiating unit that irradiates an outer peripheral edge of the workpiece, and an imaging unit that reads transmitted light that has passed through the workpiece via the translucent unit. The alignment mechanism according to claim 1, wherein the alignment mechanism is an imaging mechanism that acquires image data.   A processing apparatus comprising: the alignment mechanism according to any one of claims 1 to 3; and a processing mechanism that processes the workpiece in a state where the center of the workpiece is aligned with the center of the holding table. Placing the workpiece on a workpiece support having a suction surface that is formed to have a larger diameter than the outer diameter of the workpiece and sucks at least the outer peripheral edge of the workpiece;
Obtaining position data of the outer peripheral edge of the workpiece adsorbed on the workpiece support;
Calculating the position data of the center of the work indicating the center of the work based on the position data of the outer peripheral edge of the work;
Placing the workpiece on the holding surface in a state where the center of the workpiece is aligned with the center of the holding surface of the holding table holding the workpiece based on the position data of the center of the workpiece. An alignment method characterized by comprising:

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