JP2016184604A - Grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device which can shorten the grinding time by reducing the amount of movement of a grindstone for grinding a work-piece.SOLUTION: A sensor 15 is moved on the work-piece surface of a portion (Wb) on one side which is located opposite, across a rotation axis O of a work-piece W, to a portion (Wa) of the work-piece W facing a grindstone 12. The sensor 15 is moved from a work-piece outer periphery position P1 to a position P2 just before the rotation axis O where there is no interference with the grindstone 12. Then, the present invention predicts a surface shape from the position P2 just before the rotation axis O of the rest of the work-piece W to the rotation axis O. In this way, a main control unit 21 controls tilt adjustment by a tilt mechanism 14.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grinding apparatus.

  Generally, in a manufacturing process of a semiconductor wafer such as a silicon wafer (hereinafter simply referred to as “wafer”), the wafer is attached on a protective tape of a frame and moved between the processes. In the grinding process for processing the surface of the wafer to obtain surface accuracy and thickness, rough grinding and fine grinding are sequentially performed on different chuck tables. For this reason, an error between lots caused by the bonding state of the protective tape or an error between chucks caused by variations in chuck shape occurs in an apparatus having a plurality of work chucks. These errors cause variations in accuracy and thickness of the processed wafer. However, in recent years, there has been a demand for further thinning of the wafer, and with the creation of through electrodes on the front and back of the wafer, there has been an increasing demand for uniformity of the wafer thickness.

  In order to solve this problem, in the wafer manufacturing process, the thickness and shape of the wafer are measured before grinding, and the tilt amount of the work chuck and the tilt angle of the grindstone are adjusted according to the shape of the existing wafer to achieve the desired grinding accuracy. A technique is also known in which thinning and variation between wafers are suppressed by finishing (see, for example, Patent Document 1).

  6 and 7 are diagrams schematically showing a configuration example of a grinding apparatus in a conventional wafer grinding process. FIG. 6 is a plan view of the grinding machine, and FIG. 7 is a side view thereof. FIG. 7 schematically shows a grinding process and a shape measurement procedure.

  6 and 7, the grinding machine 50 includes a chuck table 51, a grindstone 52, a grindstone base 53, a tilt mechanism 54, a sensor 55, and the like.

  The chuck table 51 is disposed so as to be rotatable about the rotation axis O through the tilt mechanism 54, and the tilt mechanism 54 is formed so that the inclination of the rotation axis O can be adjusted. A substantially disk-shaped wafer (work) W mounted on the chuck table 51 by affixing with a tape (not shown) on a frame (not shown) is aligned with the axis of rotation O along with the frame. And air chucked by the chuck table 51.

  The grindstone 52 is formed in a disc shape. The grindstone 52 is rotatably supported on the grindstone base 53. The grindstone 52 is disposed on one side of the rotational axis O so as to face the one-side semicircle portion Wa in a state of covering the range of the one-side semicircle portion Wa of the wafer W as shown in FIG. It can move together with the grinding wheel base 53 in the vertical direction (direction perpendicular to the paper surface).

  The sensor 54 is an optical sensor that can be detected without contact, and is attached to an arm-shaped sensor moving mechanism 58. As shown in FIG. 6, the sensor moving mechanism 58 has one end side attached to the grinding machine 50 so as to be rotatable along a horizontal plane with a drive shaft 59 as a fulcrum, and the sensor 54 is attached to the other end side. As shown in FIG. 6, the sensor moving mechanism 58 is turned around the drive shaft 59 as a fulcrum, and the sensor 55 is positioned on the opposite side of the semicircular portion Wa of the wafer W facing the grindstone 52 by the turning. It moves on the range of the semicircular part Wb on one side from the workpiece outer peripheral position P1 to the rotation axis O, scans the shape of the wafer W, and can measure the shape of the wafer W by the scan. Yes.

Next, the operation of the grinding machine 50 configured as described above will be described in the order of (a) to (e) of FIG.
(a) First, the shape of the chuck table 51 before the wafer W is placed is measured, and the measurement result is stored in a control unit (not shown).
(b) Subsequently, in a state where the grindstone 52 is moved upward together with the grindstone base 53, the wafer W before grinding is mounted on the chuck table 51 by air chucking. Next, the chuck table 51 rotates integrally with the wafer W. Further, while the grindstone 52 rotates, the grindstone 52 is lowered together with the grindstone base 53 until it comes into contact with the surface of the wafer W, and the wafer W is roughly ground.
(c) When the rough grinding of the wafer W is finished, the grindstone 52 moves to an upper position where it does not interfere with the sensor 55 together with the grindstone table 53, and then the shape of the wafer W is measured by the sensor 55. In the measurement of this shape, the sensor 55 rotates horizontally along with the sensor moving mechanism 58 with the drive shaft 59 as a fulcrum, moves from the workpiece outer peripheral position P1 to the rotation axis O, and scans the shape of the wafer W. Data measured by the sensor 55 is sent to a control unit (not shown), and the control unit calculates measurement data. Further, after the measurement, the sensor 55 moves together with the sensor 55 to a position where it does not interfere with the grindstone 52.
(d) Further, the control unit controls the tilt mechanism 54 in accordance with the existing wafer shape from the calculation result, and controls the tilt of the rotation axis O of the chuck table 51 via the tilt mechanism 54. That is, the relative positional relationship between the wafer W and the grindstone 52 is adjusted by controlling the inclination of the rotation axis O.
(e) Next, the chuck table 51 is rotated integrally with the wafer W, and is lowered together with the grindstone table 53 until the grindstone 52 comes into contact with the surface of the wafer W while rotating, and the wafer W is precisely ground. Thereby, the thickness of the wafer W is uniformly ground, and the processing from the rough grinding to the fine grinding of the wafer W is completed. In this grinding procedure, variations between the wafers W are suppressed, and high accuracy and thickness uniformity can be obtained.

JP2003-25197A.

  In the method of adjusting the relative positional relationship between the wafer W and the grindstone 52 in the conventional grinding apparatus described above, when the rough grinding of the wafer W is finished and then the shape of the wafer W is measured by the sensor 55, the sensor 55 is a sensor. The workpiece moves from the workpiece outer peripheral position P1 to a position on the rotation axis O together with the moving mechanism 58, and the measurement is performed on the rotation axis O by scanning the sensor 55 across the wafer W and the grindstone 52. Therefore, the grindstone 52 largely moves to an upper position together with the grindstone base 53a in order to avoid interference with the sensor 55, and measurement is performed after a large gap is formed between the grindstone 52 and the wafer W. Therefore, since the amount of vertical movement of the grindstone 52 increases, the grinding processing time also increases, causing a problem. In the conventional grinding apparatus, the stroke of the grindstone 52 moving in the vertical direction is 100 mm, the moving speed is 10 mm / sec, and the retreat operation time is 20 sec.

  Therefore, there is a technical problem to be solved in order to provide a grinding apparatus capable of reducing the grinding processing time by reducing the moving amount of the grindstone for grinding the workpiece. The purpose is to solve.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a workpiece holding portion capable of rotatably supporting a substantially disk-shaped workpiece, and a part of the workpiece. And a grindstone that grinds the surface of the workpiece, a grindstone support mechanism that can rotatably support the grindstone, and a tilt that can adjust the tilt of the rotation axis of the workpiece by tilting the workpiece holding portion. A mechanism, a sensor capable of measuring the shape of the workpiece, a part of the workpiece facing the grindstone, and a portion of the workpiece located on the opposite side across the rotation axis of the workpiece, from the workpiece outer peripheral position, A sensor moving mechanism that can move integrally with the sensor to a position before the rotation axis that does not interfere with the grindstone, and a shape from the position before the rotation axis of the workpiece to the position of the rotation axis based on the measurement result of the sensor Predict, to provide a grinding apparatus and a control means for controlling the tilt adjustment by the tilt mechanism to calculate the tilt correction amount.

  According to this configuration, the sensor for measuring the shape of the workpiece moves from the outer peripheral position of the workpiece to a position before the rotation axis that does not interfere with the grindstone, and the measurement of the shape from the position before the remaining rotation axis to the rotation axis is Prediction is performed based on the result of the shape data of the existing wafer, and measurement is not performed by actually moving (scanning). Therefore, the sensor does not scan and measure between the wafer and the grindstone. Therefore, unlike the conventional device, it is not necessary to move the grindstone to the upper retreat position and make a gap for scanning each time measurement is performed. From machining to precision grinding, machining can be performed almost continuously. Thereby, the grinding processing time can be shortened.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the control unit stores in advance a data map including data for predicting a shape from a position before the rotation axis of the workpiece to a position of the rotation axis. A grinding apparatus is provided.

  According to this configuration, the prediction of the shape from the position before the rotation axis to the remaining rotation axis is a data map including a data pattern created based on the shape data of the existing wafer W stored in advance in the control means. This can be easily done with reference to FIG.

  According to a third aspect of the present invention, there is provided the grinding apparatus according to the first or second aspect, wherein the sensor is a scanning non-contact thickness measuring sensor.

  According to this configuration, the shape of the wafer can be measured in a non-contact state by using a scanning non-contact type thickness measuring sensor.

  According to a fourth aspect of the present invention, in the configuration of the first, second, or third aspect, in the rotation direction of the workpiece, the sensor is disposed on the downstream side of the grindstone, and grinding water is disposed on the upstream side of the grindstone. Provided is a grinding apparatus provided with a slurry supply mechanism for supplying

  According to this configuration, the slurry supply mechanism for supplying the grinding water is disposed on the upstream side of the grindstone, and the sensor is provided on the downstream side of the grindstone. Therefore, most of the grinding water supplied from the slurry supply mechanism is wiped off at the portion of the grindstone, and the grinding water hardly affects the measurement of the downstream sensor.

  A fifth aspect of the invention provides a grinding apparatus according to the first, second, third, or fourth aspect, wherein the workpiece is a semiconductor wafer.

  According to this configuration, the semiconductor wafer can be easily ground and a semiconductor wafer having high accuracy and uniform thickness can be easily obtained.

  According to the grinding apparatus of the present invention, the amount of movement of the grindstone for grinding the workpiece can be reduced, the grinding processing time can be shortened, and the productivity can be improved. In addition, the workpiece can be ground with high accuracy, and a workpiece having a uniform thickness can be easily obtained, contributing to the improvement of quality.

It is a top view of the grinding-work apparatus in the semiconductor manufacturing process shown as embodiment of this invention. It is a schematic diagram of the grinding apparatus shown in FIG. It is sectional drawing of the same grinding processing apparatus cut | disconnected in the AA position in FIG. It is a block diagram which shows an example of the control system which controls the drive of a grinding processing apparatus same as the above. It is a figure explaining the control procedure of a grinding apparatus same as the above. It is a top view of the grinding-work apparatus shown as an example of the past. It is a side view which shows the conventional grinding processing apparatus typically.

  In order to achieve an object of the present invention, which is to provide a grinding apparatus capable of shortening a grinding processing time by reducing a moving amount of a grindstone for grinding a wafer, a substantially disk-shaped workpiece can be rotated. A workpiece holding portion that can be supported; a grindstone that is disposed to face a part of the workpiece and that grinds the surface of the workpiece; a grindstone support mechanism that can rotatably support the grindstone; and the workpiece holding portion is tilted. A tilt mechanism that can adjust the tilt of the rotation axis of the workpiece, a sensor that can measure the shape of the workpiece, a part of the workpiece that faces the grindstone, and a position on the opposite side across the rotation axis of the workpiece A sensor moving mechanism capable of moving integrally with the sensor from a work outer peripheral position to a position before the rotation axis that does not interfere with the grindstone, and based on a measurement result of the sensor. It predicts the shape from the axis of rotation before the position of the click to the position of the axis of rotation, was achieved by calculate the tilt correction amount and a control means for controlling the tilt adjustment by the tilt mechanism.

  Hereinafter, a grinding apparatus according to an embodiment of the present invention will be described when applied to the case of manufacturing a wafer in a semiconductor manufacturing apparatus.

  1 to 3 show a grinding apparatus in a semiconductor manufacturing process as an embodiment of the present invention. FIG. 1 is a plan view of the grinding apparatus, and FIG. 2 is a schematic view of a main part of the grinding apparatus. FIG. 3 is a schematic cross-sectional view of the grinding apparatus cut at the position AA in FIG.

1 and 2, the grinding apparatus 10 includes a chuck table 11 and a grindstone 1.
2, a grindstone base 13, a tilt mechanism 14, a sensor 15, a coolant supply mechanism 17 as a slurry supply mechanism, and the like.

  The chuck table 11 is disposed so as to be able to rotate in the clockwise direction (the direction of the arrow 31 in FIG. 1) about the rotation axis O via the tilt mechanism 14. Is formed so that it can be adjusted in the XY direction. On the chuck table 11, as shown in FIG. 1, a substantially disk-shaped wafer (work) W mounted by sticking with a tape (not shown) on the substrate 16 rotates around its center. It is placed together with the substrate 16 in accordance with the axis O, and air chucked by the chuck table 11.

  The grindstone 12 is formed in a disc shape. The grindstone 12 is supported on the grindstone base 13 so as to be rotatable in the clockwise direction (the direction of the arrow 32 in FIG. 1). As shown in FIGS. 1 and 2, the grindstone 12 covers a part of the wafer W, that is, the range of the semicircular portion Wa on one side (the upper side of the position of the line AA in FIG. 2). It is arranged on one side so as to face the one-side semicircular portion Wa, and is movable together with the grindstone table 13 in the vertical direction (direction perpendicular to the paper surface).

  The sensor 15 is an optical sensor that can be detected without contact, and is attached to an arm-shaped sensor moving mechanism 18. As shown in FIGS. 1 and 2, the sensor moving mechanism 18 has one end side rotatably attached to the drive shaft 19 of the apparatus main body 10 a with the drive shaft 19 as a fulcrum, and the sensor 15 on the other end side. Is attached. The sensor moving mechanism 18 is turned along a horizontal plane (the upper surface of the apparatus main body 10a) with the drive shaft 19 as a fulcrum, and the sensor 15 is opposite to the semicircular portion Wa of the wafer W facing the grindstone 12 by the turning. A position on the one side of the semicircular portion Wb, which is a portion located at the front, from the workpiece outer peripheral position P1 (a position indicated by a solid line in FIG. 1) toward the rotational axis O, a position in front of not interfering with the grindstone 12 It moves to P2 (position indicated by a dotted line in FIG. 1), scans the shape of the wafer W, and can measure the shape of the wafer W by the scan.

  The coolant supply mechanism 17 is for supplying grinding water (cooling water) from the nozzle between the grindstone 12 and the wafer W. The coolant supply mechanism 17 is disposed on the upstream side of the grindstone 12 in the rotation direction of the wafer W (rotation direction of the chuck table 11), and the sensor 15 is disposed on the downstream side of the grindstone 12. Therefore, since most of the grinding water supplied from the coolant supply mechanism 17 is wiped off at the portion of the grindstone 12, even if the sensor 15 performs measurement in an online state where grinding is performed, the grinding water is on the downstream side. The influence on the measurement of the sensor 15 is reduced.

  FIG. 4 is a configuration block diagram of a control system that controls driving of the grinding apparatus 10. In the figure, the control system of the grinding apparatus 10 includes a main control unit 21 as a control means for controlling the entire grinding apparatus 10 according to a predetermined procedure, and the rotation of the chuck table 11 and the opening / closing operation of the chuck. A chuck table control unit 22 for controlling, a grindstone rotation drive control unit 23 for controlling the rotation of the grindstone 12, a sensor moving mechanism drive control unit 24 for controlling the turning operation of the sensor moving mechanism 18, and a tilt for controlling the tilt mechanism 14 A mechanism control unit 25 and the like are provided.

  The main control unit 21 is a main control unit, for example, a computer. The main control unit 21 includes a memory 21a having a control system program for controlling the entire grinding apparatus 10 according to a predetermined procedure, and the shape data of the existing wafer W is digitized and stored in advance as a data pattern. A memory 21b that stores various data including a map that can be read and written, a CPU (arithmetic processing unit) 21c that performs arithmetic processing on data input from the memories 21a and 21b and the sensor 15, and the like.

  Further, in the main control unit 21, the result obtained by scanning the shape of the wafer W by moving the sensor 15 from the workpiece outer peripheral position P1 to the position P2 before the interference with the grindstone 12, and the existing wafer W Referring to the data pattern in the map 22b stored in advance by converting the shape of the data into, for example, it is determined which pattern obtained from the current scan corresponds to the pattern obtained from the existing wafer W The shape in the range from the remaining position P2 on the wafer W to the central axis O can be calculated and predicted. The main controller 21 can adjust the tilt of the chuck table 11 by controlling the tilt mechanism 14 via the tilt mechanism controller 25 based on the prediction.

FIG. 5 is a diagram illustrating an example of an operation procedure of the grinding apparatus 10. The operation of the grinding apparatus 10 will be described in the order of (a) to (f) in FIG.
(a) First, the shape of the chuck table 11 before the wafer W is placed is measured, and the measurement result is stored in advance in the memory 21 b of the main control unit 21.
(b) Next, in a state where the grindstone 12 is moved upward together with the grindstone table 13, the wafer W before grinding is mounted on the chuck table 11 by air chucking. In addition, the chuck table 11 rotates integrally with the wafer W, and while the grindstone 12 rotates, the chuck table 11 descends with the grindstone table 13 until it contacts the surface of the wafer W, while supplying grinding water from the coolant supply mechanism 17. Perform rough grinding. After the rough grinding of the wafer W, supply of the grinding water by the coolant supply mechanism 17 is stopped, and the grindstone 12 is moved upward to a position that does not interfere with the tilt control of the chuck table 11, that is, the tilt control of the chuck table 11 by the tilt mechanism 14. It is moved together with the grindstone table 13.
(c) Thereafter, the shape of the wafer W is measured by the sensor 15. In the measurement of this shape, the sensor 15 rotates horizontally with the sensor moving mechanism 18 using the drive shaft 19 as a fulcrum, and moves from the workpiece outer peripheral position P1 shown in FIGS. 1 and 2 to a position P2 that does not interfere with the grindstone 12. The shape of the wafer W is scanned and the shape of the wafer W is measured. Then, the measurement result of the sensor 15 is input to the main controller 21 as data.
(d) The main control unit 21 refers to the data measured by the sensor 15 and the data pattern stored in advance in the data map 22b to determine which data pattern corresponds to the remaining data on the wafer W. The shape in the range from the position P2 to the central axis O is calculated and predicted.
(e) The main control unit 21 controls the tilt mechanism 14 via the tilt mechanism control unit 25 based on the predicted value, and adjusts the tilt of the rotation axis O of the chuck table 11. That is, the relative positional relationship between the wafer W and the grindstone 52 is adjusted.
(f) Next, the chuck table 51 is rotated together with the wafer W, and is lowered together with the grindstone table 53 until the grindstone 52 contacts the surface of the wafer W while rotating, and the grinding water is supplied from the coolant supply mechanism 17. However, precise grinding of the wafer W is performed. Thereby, the wafer W is finely ground so that the thickness is uniform, and a series of processes from rough grinding to fine grinding of the wafer W is completed. In this grinding procedure, variations between the wafers W are suppressed, and high accuracy and thickness uniformity can be obtained.

  Therefore, according to the grinding apparatus 10 according to the present embodiment, the sensor 15 that measures the shape of the wafer (work) W moves from the work outer peripheral position P1 to the position P2 before the rotation axis O that does not interfere with the grindstone 12. The shape from the position P2 before the remaining rotation axis O to the rotation axis O (the shape in the range S2 shown in FIG. 2) refers to the data pattern in the data map 22b measured in advance on the existing wafer W. Predict, and do not actually scan. As a result, the sensor 15 does not scan and measure between the wafer W and the grindstone 12, so the conventional apparatus that has moved the sensor to the position of the rotation axis O performs the measurement. Each time, it has been necessary to move the grindstone to the upper retreat position to create a gap, but this is not necessary in the grinding apparatus 10 of the present embodiment. For this reason, the vertical movement amount of the grindstone is reduced, and since the machining can be performed almost continuously from the rough grinding process to the fine grinding process, the grinding process time can be shortened. Furthermore, the wafer W can be ground with high accuracy, and a workpiece having a uniform thickness can be easily obtained, thereby contributing to improvement in quality.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

  As described above, the present invention has been described by taking the grinding apparatus in the semiconductor manufacturing process as an example. However, the present invention can be applied not only to the semiconductor manufacturing process but also to a general grinding apparatus.

DESCRIPTION OF SYMBOLS 10 Grinding apparatus 10a Apparatus main body 11 Chuck table (work holding part)
12 Grinding wheel 13 Grinding wheel base 14 Tilt mechanism 15 Sensor 16 Substrate 17 Coolant supply mechanism 18 Sensor moving mechanism 19 Drive shaft 21 Main control section (control means)
21a Memory (program)
21b Memory (data map)
21c CPU (arithmetic processing unit)
22 Chuck table control unit 23 Grinding wheel rotation drive control unit 24 Sensor movement mechanism drive control unit 25 Tilt mechanism control unit W Wafer (workpiece)
Wa, Wb Semicircular part O Rotation axis P11 Workpiece outer peripheral position P2 Position on work

Claims (5)

A workpiece holding part capable of rotatably supporting a generally disk-shaped workpiece;
A grindstone disposed opposite to a part of the workpiece and grinding the workpiece surface;
A grindstone support mechanism capable of rotatably supporting the grindstone;
A tilt mechanism capable of adjusting the tilt of the rotation axis of the workpiece by tilting the workpiece holding portion;
A sensor capable of measuring the shape of the workpiece;
The sensor and the part of the workpiece facing the grindstone and the workpiece surface of the portion located on the opposite side across the rotation axis of the workpiece from the outer peripheral position of the workpiece to a position just before the rotation axis that does not interfere with the grindstone. A sensor moving mechanism that can move together;
Control means for predicting the shape of the workpiece from the position in front of the rotation axis to the position of the rotation axis based on the measurement result of the sensor, calculating a tilt correction amount, and controlling tilt adjustment by the tilt mechanism;
A grinding apparatus comprising:   2. The grinding process according to claim 1, wherein the control means stores in advance a data map including data for predicting a shape from a position before the rotation axis of the workpiece to a position of the rotation axis. 3. apparatus.   The grinding apparatus according to claim 1, wherein the sensor is a scanning non-contact type thickness measuring sensor.   The said sensor is arrange | positioned in the rotation direction of the said workpiece | work at the downstream of the said grindstone, The slurry supply mechanism which supplies grinding water to the upstream of the said grindstone is arrange | positioned, The grinding apparatus according to 2 or 3.   The grinding apparatus according to claim 1, 2, 3, or 4, wherein the workpiece is a semiconductor wafer.

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