JP5353541B2 - Chemical mechanical polishing apparatus and operation method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for operating a chemical-mechanical polishing apparatus capable of contributing to stabilization of processing conditions in chemical-mechanical polishing. <P>SOLUTION: The method for operating the chemical-mechanical polishing apparatus including a head for rotating a wafer while holding it, in which the wafer is polished by being brought into contact with a rotating pad while being rotated, and the position of the wafer in a circumferential direction of the pad relatively moves during polishing the wafer associated with the rotation of the pad, includes the steps of: measuring physical quantities corresponding to the running torque of the head at a plurality of positions in circumferential directions on the pad; and specifying an abnormal part on the pad based on the physical quantities corresponding to the running torque of the head, measured at the plurality of positions on the pad. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a chemical mechanical polishing apparatus and an operation method thereof.

  In CMP (Chemical Mechanical Polishing), a polishing slurry (slurry: a mixture of powdered solid and liquid) is dropped on a rotating polishing pad with a polishing cloth affixed to the surface, In this method, the wafer surface is polished by pressing a separately fixed wafer against the polishing pad. CMP is used, for example, for forming an element isolation insulating film by STI (shallow trench isolation), forming a tungsten plug, and forming a copper wiring by damascene.

  Since it is important to obtain a flat surface in the manufacturing process of a semiconductor device, CMP is frequently used as described above. Therefore, a technique for performing CMP while stabilizing the processing conditions is desired.

JP 2001-514092 A JP-A-11-99467

  Since it is important to obtain a flat surface in the manufacturing process of a semiconductor device, CMP is frequently used as described above. Therefore, a technique for performing CMP while stabilizing the processing conditions is desired. In order to stabilize the processing conditions, it is important to easily identify abnormal points on the polishing pad. An object of the present invention is to provide a chemical mechanical polishing apparatus that contributes to stabilization of processing conditions in chemical mechanical polishing and an operation method thereof.

  According to one aspect of the present invention, the rotating wafer comes into contact with the rotating pad to polish the wafer, and the position of the wafer in the circumferential direction of the pad relatively moves with the rotation of the pad during polishing. A method of operating a chemical mechanical polishing apparatus having a head for holding and rotating the wafer, the step of measuring physical quantities corresponding to the rotational torque of the head at a plurality of circumferential positions on the pad; There is provided a method of operating a chemical mechanical polishing apparatus comprising a step of identifying an abnormal location on the pad based on a physical quantity corresponding to the rotational torque of the head measured at a plurality of positions on the pad.

  An abnormal location on the pad is identified based on a physical quantity corresponding to the rotational torque of the head measured at a plurality of circumferential positions on the pad. Thereby, it can be detected that an in-plane distribution is generated in the pad state.

FIG. 1 is a schematic perspective view showing a CMP apparatus according to a first embodiment of the present invention. FIG. 2 is a flowchart schematically showing a method of operating the CMP apparatus of the first (and second) embodiment. FIG. 3 is a table summarizing measurement time, torque values, measurement points, determination results, and the like for the operation method of the CMP apparatus of the first (and second) embodiment. FIG. 4A and FIG. 4B are schematic perspective views showing wafer trajectories for avoiding abnormal portions in the operation method of the CMP apparatus of the first (and second) embodiment. FIG. 5 is a schematic perspective view showing a CMP apparatus according to the second embodiment. FIG. 6 is a schematic perspective view showing the CMP apparatus used for the preliminary study. FIG. 7 is a timing chart showing the flow of the entire polishing step. FIG. 8 is a schematic cross-sectional view of a wafer on which an element isolation insulating film is formed by STI. FIG. 9 is a graph showing how the head rotational torque and the dishing amount change with respect to the number of CMP processed wafers. FIG. 10 is a box-and-whisker plot in which all the head rotation torque data is plotted at three levels when the average head rotation torque (per wafer) is small, medium, and large. FIG. 11 is a schematic plan view showing the head rotational torque measurement points on the pad. 12A and 12B are graphs in which cumulative probabilities are plotted with respect to the head rotation torque at each measurement point A to C at times when the average head rotation torque is small and large.

  Prior to a description of a chemical mechanical polishing (CMP) apparatus according to an embodiment of the present invention and an operation method thereof, a preliminary study performed by the present inventor will be described.

  FIG. 6 is a schematic perspective view showing a CMP apparatus in advance examination. A pad (polishing cloth) 1 is attached to the upper surface of a disk-shaped platen (surface plate) 2. When the platen 2 is rotated via the platen drive shaft 3, the pad 1 is rotated. The rotation direction of the pad 1 is, for example, counterclockwise when viewed from above the pad 1, and the rotation speeds of the platen 2 and the pad 1 are 50 rpm to 200 rpm (for example, 100 rpm).

  A wafer 11 that is an object to be polished is held on the lower surface of a disk-shaped head (mount plate) 12. When the head 12 is rotated by the head rotation motor 14 via the head drive shaft 13, the wafer 11 rotates. The rotation direction of the wafer 11 is aligned with the rotation direction of the pad 1, for example, counterclockwise when viewed from above the pad 1. The rotational speeds of the head 12 and the wafer 11 are 50 rpm to 200 rpm (for example, 150 rpm).

  The drive current of the head rotation motor 14 is controlled so that the head 12 is rotated at a desired number of rotations. As the head rotation motor 14, a rotation motor or a drive motor in which the drive current and the rotation torque are proportional can be used.

  The driving current of the head rotating motor 14 corresponds to the rotating torque of the head 12, and the rotating torque of the head 12 can be measured based on the driving current of the head rotating motor 14. A circuit for measuring the rotational torque of the head 12 is collectively referred to as a head rotational torque measuring device 17.

  A head support arm 15 attached to the support shaft 16 moves the head 12 in the vertical direction. A slurry (polishing liquid) supply nozzle 21 supplies the slurry onto the pad 1. The surface of the wafer 11 is polished by pressing the rotating wafer 11 against the pad 1 while rotating the pad 1 supplied with the slurry. As the pad 1 rotates, the relative position of the wafer 11 on the pad 1 moves in the pad circumferential direction.

  The diameter of the wafer 11 is, for example, 12 inches, and the diameter of the pad 1 is slightly larger than twice the wafer diameter, for example, 30 inches. With respect to the radial direction of the pad 1, the wafer 11 is disposed between the center and the edge of the pad 1 and polishing is performed.

  The wafer holding surface of the head 12 is about the same size as the wafer 11 and has a diameter of about 12 inches, for example. The pad holding surface of the platen 2 is about the same size as the pad 1 and has a diameter of about 30 inches, for example.

  Next, a polishing step for one wafer will be described with reference to FIG. FIG. 7 is a timing chart showing the flow of the entire polishing step, where the horizontal axis indicates the polishing time and the vertical axis indicates the process step. The polishing step for one wafer is roughly divided into four steps: pad conditioning, ramp-up, main polishing, and pure water rinsing.

  The ramp-up step subsequent to the pad conditioning step includes a wafer loading operation, a wafer rotation starting operation, and the like. In the main polishing step, polishing is performed in a state where the rotation number of the pad and the wafer is steady. The main polishing time is about 80 seconds, for example.

  Process data during the polishing step (head rotation speed, platen rotation speed, head rotation torque, polishing pressure, slurry flow rate, etc.) is acquired at predetermined measurement intervals. In this preliminary study, data was acquired at 1-second intervals. The number of acquired data in the main polishing step per wafer is about 80 pieces.

  Next, dishing will be described with reference to FIG. FIG. 8 is a schematic cross-sectional view of a wafer on which an element isolation insulating film STI is formed by shallow trench isolation (STI). When CMP is performed on the element isolation insulating film STI, the central portion is polished more than the end portion, and dishing occurs in which the central portion sinks. It has been found that dishing affects transistor characteristics. The dishing amount is defined by the amount of subsidence at the center with respect to the edge. Note that the dishing amount tends to increase as the width of the element isolation insulating film increases.

  Next, with reference to FIG. 9, a description will be given of a study examining the relationship between the head rotation torque and the dishing amount. FIG. 9 is a graph showing how the head rotational torque and the dishing amount change with respect to the number of CMP processed wafers.

  The lot number is shown on the horizontal axis. Each lot includes about 10 to 20 wafers. The lot on the right side of the horizontal axis is processed later. During the processing of all lots of wafers, three pad changes are performed (ie, four pads are used). The processing period in each pad is referred to as processing period T1 to processing period T4. In principle, the pad is replaced every time a certain number of wafers are processed. However, if any trouble occurs, the pad is replaced without waiting for the replacement cycle.

  The head rotation torque can be evaluated by the drive current of the head rotation motor. The left vertical axis indicates the current corresponding to the head rotational torque in A units. The average value of the head rotation motor current in the main polishing step for each wafer is shown by a rhombus plot. Hereinafter, the current corresponding to the head rotation torque may be simply referred to as head rotation torque.

  The right vertical axis shows the dishing amount in nm. Although different types of semiconductor integrated circuits are formed on a wafer depending on the lot, an element isolation insulating film having a common shape by STI is formed as a test pattern on every wafer, and an STI test pattern (40 μm × 40 μm square shape) ) Is measured. The dishing amount for each wafer is shown as a square plot.

  The inventor of the present application has found a tendency that the head rotation torque increases and the dishing amount increases as the number of accumulated processing wafers increases when polishing with the same pad. It is thought that an increase in the head rotation torque is causing an increase in dishing amount. Such a tendency is seen in the processing periods T1 to T3 of the first to third pads.

  In order to suppress variations in transistor characteristics, it is desirable to suppress variations in dishing amount. For this purpose, it is considered effective to suppress fluctuations in the head rotation torque during CMP.

  Next, the reason for the increase in head rotation torque will be considered.

  FIG. 10 shows the total head rotation torque for several wafers in a lot at each of the three levels (initial, intermediate, and late) when the average head rotation torque is small, medium, and large in the processing period T1 of FIG. It is a box-and-whisker plot in which data is plotted.

  From this, it can be seen that the increase in the average head rotation torque is due to an increase in the variation of data toward the larger torque as the cumulative processing number increases.

  In this preliminary study, the pad is rotated at 100 rpm, and the measurement interval of the head rotational torque is 1 second. Since the rotation period of the pad is 0.6 seconds, the head rotation torque is measured every (1 + 2/3) rotation.

  FIG. 11 is a schematic plan view showing the head rotational torque measurement points on the pad 1. An example in which the pad 1 rotates counterclockwise is shown. Since the head rotational torque is measured every (1 + 2/3) rotation, the three measurement points A, B, and C are located at positions that equally divide the pad 1 into three in the circumferential direction (that is, every azimuth angle of 120 °). Be placed.

  After measurement at point A, rotate (1 + 2/3) to measure point B, after measurement at point B, rotate (1 + 2/3) to measure point C, and after measurement at point C, ( 1 + 2/3) Rotate and measure point A again. Thus, the measurement at the three points A to C is repeated.

  12A and 12B are graphs in which cumulative probabilities are plotted with respect to the head rotation torque at each measurement point A to C at the time when the average head rotation torque is small and large, respectively.

  As shown in FIG. 12A, when the average head rotation torque is small, the distribution shape of the cumulative probability varies little between the measurement points A to C.

  On the other hand, as shown in FIG. 12B, when the average head rotational torque is large, the variation in the distribution shape of the cumulative probability is large between the measurement points A to C. In particular, the head rotation torque at the measurement points B and C is shifted to a higher value than that at the measurement point A.

  From this, it is considered that the increase in the average head rotation torque is caused by the increase in the head rotation torque at some measurement points (points B and C in this example).

  To summarize the above considerations, as the cumulative number of processes increases, an abnormality (deterioration) in which resistance increases in a part of the area on the pad (in-plane distribution occurs in the state of the pad), and a desired area is detected at the abnormal part. It is considered that the head rotation torque is increasing in order to maintain the head rotation speed.

  Based on the above-described prior examination, the CMP apparatus and its operation method according to the first embodiment of the present invention will be described next.

  FIG. 1 is a schematic perspective view showing a CMP apparatus according to the first embodiment. The basic structure of the CMP apparatus is the same as that of the CMP apparatus described with reference to FIG. 6 in the preliminary study, and the difference from the CMP apparatus of the preliminary study will be described below.

  In the CMP apparatus according to the first embodiment, the diameters of the pad 1a and the platen 2a are larger than the diameters of the pad 1 and the platen 2 of the apparatus studied in advance. The diameter of the wafer 11 is, for example, 12 inches as in the previous study. The diameter of the pad 1a of the first embodiment is, for example, 60 inches, which is slightly larger than four times the wafer diameter. Corresponding to the pad 1a, the diameter of the platen 2a is also about 60 inches, for example. That is, the radius of the pad 1a (or the pad holding surface of the platen 2a) is ensured to be at least twice the diameter of the wafer 11 (or the wafer holding surface of the head 12).

  In the CMP apparatus of the first embodiment, the head support arm 31 is movable in the radial direction of the pad 1a, and the head 12 is moved in this direction. A head moving motor 32 moves the head support arm 31. A head moving mechanism 33 in the pad radial direction is formed including the head support arm 31 and the head moving motor 32.

  As discussed in the preliminary study, an abnormal location on the pad can be detected based on the increase in head rotation torque. As will be described in detail below, in the CMP apparatus of the first embodiment, an abnormal location on the pad is identified based on the head rotational torque, and the head 12 is moved in the pad radial direction so as to avoid the abnormal location on the pad. Move.

  The control device 100 performs data processing necessary for such an operation, control of the head moving mechanism 33, and the like. As described in the preliminary examination, the drive current of the head rotation motor 14 can be measured as a physical quantity corresponding to the head rotation torque, but a head rotation torque measuring device that estimates the head rotation torque by other methods is used. It is also possible.

  Next, a method for operating the CMP apparatus according to the first embodiment will be described.

  FIG. 2 is a flowchart schematically showing a method of operating the CMP apparatus according to the first embodiment. The main polishing step will be described. Other process steps (pad conditioning, ramp-up, pure water rinsing) are not particularly different from the operation method of the CMP apparatus studied in advance. First, in step S1, main polishing is started.

  Next, in step S2, the head rotational torque is measured. Here, a method for measuring the head rotation torque, which is desirable for specifying an abnormal portion on the pad, will be considered. The pad rotation speed is set to 100 rpm as in the previous study. The rotation period of the pad is 0.6 seconds. The time of the main polishing step is about 80 seconds, for example.

  In order to detect the in-plane distribution of the state of the pad, it is desired to measure the head rotation torque at a plurality of circumferential positions on the pad. However, if the pad rotation period (and its integral multiple) is taken as the measurement interval, the measurement point becomes one place on the pad. Therefore, it is not desirable to set the pad rotation period (and its integral multiple) as the measurement interval.

  For example, in the case of measuring at two locations, the measurement interval may be set to 1/2 rotation period (or (1 + 1/2) rotation period obtained by adding an integral multiple of the rotation period, (2 + 1/2) rotation period, etc.). If the pad rotation period is 0.6 seconds, the measurement interval is 0.3 seconds, 0.9 seconds, 1.5 seconds, or the like.

  Also, for example, when measuring at three locations, 1/3 rotation period (or (1 + 1/3) rotation period, (2 + 1/3) rotation period, etc. added to integer multiple of rotation period) or 2/3 rotation) A cycle (or (1 + 2/3) rotation cycle, (2 + 2/3) rotation cycle, etc. added to an integral multiple of the rotation cycle) may be set as the measurement interval. If the pad rotation period is 0.6 seconds, the measurement interval is 0.2 seconds, 0.8 seconds, 1.4 seconds, or 0.4 seconds, 1 second, 1.6 seconds, or the like.

  If there are too many measurement points, the number of data becomes too large, or it becomes difficult to secure a sufficient number of data per measurement point. For example, the number of measurement points may be about 2 to 5 points.

  If the measurement interval is too long, it is difficult to secure a sufficient number of data per measurement point. On the other hand, even if the measurement interval is too short, it is not preferable because the number of data becomes too large. The measurement interval may be about 0.5 seconds to 2.0 seconds, for example.

  Note that the measurement interval is not limited to a constant interval, but if the measurement interval is constant, the measurement points are arranged at a constant interval (that is, with a constant azimuth angle difference) in the circumferential direction of the pad. Is easy. It is easy to suppress the measurement points from being biased to a specific portion in the pad circumferential direction.

  In the present embodiment, as in the preliminary examination, the measurement interval is 1 second, and the measurement locations are 3 locations. During the main polishing step, a total of about 80 head rotation torque data (about 27 per measurement point) is acquired.

  In step S3, based on the head rotational torque measured in step S2, it is determined whether or not the head rotational torque has changed. If it is determined in step S3 that the head rotational torque varies, the process proceeds to step S4.

  In step S4, an abnormal portion of the pad is specified.

  In step S5, the wafer trajectory is corrected to a trajectory that avoids an abnormal portion of the pad by moving the head.

  If it is determined in step S3 that the head rotational torque does not vary, the measurement point is determined to be normal, and the wafer trajectory is not corrected.

  The procedure for determining the presence or absence of fluctuations in the head rotation torque, specifying an abnormal portion of the pad, and correcting the wafer trajectory will be further described.

  First, prior to the CMP process of the embodiment, an upper limit reference value and a lower limit reference value that determine the range of allowable head rotation torque are prepared. The CMP process is performed in a state where the pad is most stable, for example, a period of 10% of the initial period of the replacement cycle (for example, when the replacement cycle is 2000 sheets, a period in which 200 sheets are processed after replacement), The maximum value and the minimum value of the rotational torque are set as the upper limit reference value and the lower limit reference value, respectively.

  The measured value of the head rotation torque tends to vary greatly. Therefore, for example, the variation can be leveled by taking a moving average every three data. Therefore, it is considered desirable to use the maximum and minimum values of moving average data.

  In FIG. 3, from the left side, lot number, wafer number, measurement time, current value corresponding to head rotation torque (simply called torque value), measurement point, moving average torque ("torque value" on the left) (Moving average), determination results, and head operation. An example of data for 30 seconds is shown.

  In step S2 of FIG. 2, the torque value is measured. The torque value is measured every measurement interval of 1 second, and the measurement point is cyclically moved from point A, point B, point C, and point A again for each measurement. For each measurement point, the moving average torque for every three data is calculated. The moving average torque is compared with the upper limit reference value and the lower limit reference value to determine whether the moving average torque is within an allowable range. For example, the upper limit reference value is 59.7 and the lower limit reference value is 26.2.

  In the example illustrated in FIG. 3, the moving average torque at the measurement time 11:01:25 (measurement time 11:01:19, 11:01:22, 11:01:25 averaged data is moved at the measurement point C. The average torque) is 60.83, which exceeds the upper reference value and is determined to be outside the allowable range. That is, it is determined that there is a fluctuation in the head rotation torque (step S3), and the torque measurement point C is specified as an abnormal location (step S4).

  Further, based on this, after the next measurement time 11:01:28 related to the measurement point C, the head is operated when passing through the point C so that the wafer trajectory avoids the point C (step S5).

  4A and 4B are schematic perspective views showing the trajectory T1 of the wafer 11 on the pad 1a to avoid the point C in which an abnormality has occurred. When no abnormality occurs in the pad (referred to as normal), the center of the wafer 11 passes through the circular trajectory T0. The radius of the track T0 at the normal time is, for example, a radius of 24 inches. The distance from the center of the pad 1a to the edge closest to the pad center of the wafer 11 moving on the normal trajectory T0 is ensured to be equal to or larger than the diameter of the wafer 11.

  As shown in FIG. 4A, when the wafer 11 approaches the abnormal point C (PC) in the pad circumferential direction with the rotation of the pad 1a, the wafer 1 is (at least) inwardly in the pad radial direction so as to approach the pad center. Move one sheet (one head). In this way, the trajectory of the wafer 11 is corrected to the trajectory T1 that avoids the abnormal point C and is shifted from the normal trajectory T0.

  Thereby, it is possible to polish the pad area inside the abnormal point C that is unused and not deteriorated. Since the radius of the pad 1a is at least twice the diameter of the wafer 11, polishing can be performed by placing the wafer 11 between the center and the edge of the pad 1a even with the corrected trajectory T1. .

  As shown in FIG. 4B, when the wafer 11 passes the abnormal point C (PC) in the pad circumferential direction, the wafer 11 is moved outward in the pad radial direction so as to move away from the center of the pad, and the wafer 11 is moved to the normal trajectory T0. Return to the top.

  In the example of data shown in FIG. 3, no abnormality has occurred at points A and B. Accordingly, it is determined that there is no fluctuation in the head rotational torque at the points A and B (step S3). For point A and point B, correction from the normal trajectory T0 is not performed.

  As shown in FIG. 3, the moving average torque at point C returns to within the allowable range at the measurement time 11:01:34, etc., but once it is determined that it is out of the allowable range, the moving average torque is thereafter allowed. Even after returning to the range, the head operation to avoid the abnormal point C is continued. This is because it is considered that the pad area in which an abnormality has occurred is unlikely to return to a normal state thereafter.

  Returning to FIG. 2, the description will be continued. In step S6, it is determined whether the remaining time of the main polishing step is sufficient. As long as the remaining time is sufficient (for example, a few seconds or more), the process returns to step S2, and the wafer trajectory is corrected in step S5 as necessary. When the remaining time is short (for example, less than 2 or 3 seconds), the process returns to step S2 and proceeds to step S7 without correcting the wafer trajectory in step S5, and the main polishing is completed.

  As described above, when the CMP apparatus of the first embodiment is used, the head rotation torque measured at a plurality of locations in the pad circumferential direction (not only the head rotation torque itself, but also a physical quantity corresponding widely to the head rotation torque). The abnormal location on the pad is identified based on It can be detected that an in-plane distribution occurs in the pad state.

  The CMP apparatus of the first embodiment further performs CMP processing on a wafer trajectory that avoids an abnormal point on the pad. Thereby, variation in CMP process conditions can be reduced. For example, variations in the shape of the element isolation insulating film due to STI from wafer to wafer are suppressed. It should be noted that the effect of reducing variations in CMP process conditions is useful not only in element isolation insulating film formation but also in CMP process used for tungsten plug formation, copper wiring formation, and the like.

  In the above embodiment, the wafer trajectory is corrected from the normal trajectory only in the vicinity of the abnormal point C, that is, the normal trajectory is returned in the vicinity of the point A and the point B where no abnormality is detected. It is possible to perform the CMP process avoiding the abnormal point C even if the wafer is kept in the pad radial direction inner position avoiding the abnormal point C without returning to the normal wafer trajectory near the point B. it can. In the vicinity of points A and B where no abnormality is detected, a larger pad area can be used by returning to the normal wafer trajectory, that is, the trajectory passing through the outer side in the pad radial direction.

  Next, a CMP apparatus according to the second embodiment and its operating method will be described. The CMP apparatus according to the first embodiment has a structure in which the head and the wafer are moved in order to obtain a wafer trajectory that avoids an abnormal point on the pad. Is also possible. In the second embodiment, a mechanism for moving the platen and the pad is employed.

  FIG. 5 is a schematic perspective view showing a CMP apparatus according to the second embodiment. Differences from the CMP apparatus of the first embodiment will be described. In the second embodiment, since the head side is not moved (in the pad radial direction), the head support arm 15 and its support shaft 16 are the same as those in the CMP apparatus studied in advance.

  The platen moving arm 35 moves the platen 2 a via the platen drive shaft 3. The platen guide member 34 guides the moving direction of the platen 2a in a direction connecting the center of the pad 1a and the center of the wafer 11 so that the wafer 11 can move in the pad radial direction relative to the pad 1a. A platen movement motor 36 moves the platen movement arm 35. A platen moving mechanism 37 is formed including the platen guide member 34, the platen moving arm 35, and the platen moving motor 36. The control device 100 controls the platen moving mechanism 37.

  Next, a method for operating the CMP apparatus of the second embodiment will be described. The operation method of the second embodiment is also shown in the flowchart shown in FIG. 2, as in the first embodiment. However, the platen and the pad are moved in order to correct the wafer trajectory in step S5.

  The movement of the relative position of the wafer 11 with respect to the pad 1a when the wafer trajectory avoiding the abnormal portion on the pad is shown in FIGS. 4A and 4B, as in the first embodiment. However, the platen and the pad are moved to make such a trajectory.

  Even in the CMP apparatus of the second embodiment, the CMP process can be performed on the wafer trajectory avoiding the abnormal part on the pad, and the variation in the CMP process condition can be reduced.

  As described above in the first and second embodiments, in order to obtain a wafer trajectory that avoids an abnormal point on the pad, the relative position of the wafer with respect to the pad (the relative position of the head with respect to the platen) is set. To move in the radial direction, either a method of moving the head and the wafer held by the head or a method of moving the platen and the pad held by the platen can be used. Since the head is smaller and lighter than the platen, it is considered easier to move the head and wafer than to move the platen and pad.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

The following additional notes are further disclosed with respect to the embodiment including the first and second examples described above.
(Appendix 1)
The rotating wafer is brought into contact with the rotating pad to polish the wafer, and the position of the wafer in the circumferential direction of the pad relatively moves with the rotation of the pad during polishing to hold and rotate the head. A method of operating a chemical mechanical polishing apparatus having:
Measuring a physical quantity corresponding to the rotational torque of the head at a plurality of circumferential positions on the pad;
A method of operating a chemical mechanical polishing apparatus, comprising: identifying an abnormal location on the pad based on a physical quantity corresponding to the rotational torque of the head measured at a plurality of positions on the pad.
(Appendix 2)
The step of identifying an abnormal location on the pad includes the step of identifying the measurement position where the physical quantity corresponding to the rotational torque of the head is outside a predetermined range as the abnormal location on the pad. Operation method of chemical mechanical polishing equipment.
(Appendix 3)
The operation method of the chemical mechanical polishing apparatus according to appendix 1 or 2, wherein the head is rotated by a head rotation motor, and a drive current of the head rotation motor is measured as a physical quantity corresponding to the rotation torque of the head.
(Appendix 4)
further,
Any one of Supplementary notes 1 to 3 including a step of moving a relative position of the wafer with respect to the pad with respect to a radial direction of the pad so as to be a trajectory of the wafer avoiding the specified abnormal portion on the pad. A method for operating the chemical mechanical polishing apparatus according to claim 1.
(Appendix 5)
The step of moving the relative position of the wafer with respect to the pad with respect to the radial direction of the pad moves the relative position of the wafer with respect to the pad to the inside of one or more wafers with respect to the radial direction of the pad. A method for operating the chemical mechanical polishing apparatus according to claim 1.
(Appendix 6)
The step of moving the relative position of the wafer with respect to the pad with respect to the radial direction of the pad is performed by moving the relative position of the wafer with respect to the pad inward of the pad in the radial direction of the pad. The operation method of the chemical mechanical polishing apparatus according to appendix 4 or 5, wherein when the abnormal portion passes in the circumferential direction, the relative position of the wafer to the pad is moved outward in the pad radial direction.
(Appendix 7)
The step of moving the relative position of the wafer with respect to the pad with respect to the radial direction of the pad is the chemical mechanical polishing apparatus according to any one of appendices 4 to 6, wherein the head and the wafer held by the head are moved. how to drive.
(Appendix 8)
A platen that holds and rotates the pad;
A head that holds and rotates the wafer so that the rotating wafer contacts the rotating pad and is polished;
A torque measuring device that measures physical quantities corresponding to the rotational torque of the head at a plurality of circumferential positions on the pad;
A chemical mechanical polishing apparatus comprising: a control device that identifies an abnormal location on the pad based on the measured physical quantity.
(Appendix 9)
9. The chemical mechanical polishing apparatus according to appendix 8, wherein the control device identifies a measurement position where a physical quantity corresponding to the rotational torque of the head is outside a predetermined range as an abnormal location on the pad.
(Appendix 10)
And a head rotation motor for rotating the head.
The chemical mechanical polishing apparatus according to appendix 8 or 9, wherein the torque measuring device measures the drive current of the head rotation motor as a physical quantity corresponding to the rotation torque of the head.
(Appendix 11)
further,
A moving mechanism for moving the relative position of the head with respect to the platen with respect to the radial direction of the pad;
The control device moves the relative position of the head with respect to the platen by controlling the moving mechanism so that the trajectory of the wafer avoiding the abnormal portion on the specified pad is determined. The chemical mechanical polishing apparatus according to any one of the above.
(Appendix 12)
The chemical mechanical polishing apparatus according to appendix 11, wherein the control device controls the moving mechanism to move the relative position of the wafer with respect to the pad inward by one or more wafers with respect to the radial direction of the pad.
(Appendix 13)
The control device controls the moving mechanism to move the relative position of the wafer to the pad in the pad radial direction in front of the abnormal location in the pad circumferential direction, and to detect the abnormal location in the pad circumferential direction. 13. The chemical mechanical polishing apparatus according to appendix 11 or 12, wherein if it has passed, the relative position of the wafer to the pad is moved outward in the pad radial direction.

DESCRIPTION OF SYMBOLS 1a Pad 2a Platen 3 Platen drive shaft 11 Wafer 12 Head 13 Head drive shaft 14 Head rotation motor 16 Support shaft 17 (Measurement head) Torque measuring device 21 Slurry supply nozzle 31 Head support arm 32 Head movement motor 33 Head movement mechanism 100 Control device

Claims (5)

The rotating wafer is brought into contact with the rotating pad to polish the wafer, and the position of the wafer in the circumferential direction of the pad relatively moves with the rotation of the pad during polishing to hold and rotate the head. A method of operating a chemical mechanical polishing apparatus having:
Measuring a physical quantity corresponding to the rotational torque of the head at a plurality of circumferential positions on the pad;
A method of operating a chemical mechanical polishing apparatus, comprising: identifying an abnormal location on the pad based on a physical quantity corresponding to the rotational torque of the head measured at a plurality of positions on the pad. further,
The chemical machine according to claim 1, further comprising a step of moving a relative position of the wafer with respect to the pad with respect to a radial direction of the pad so as to be a trajectory of the wafer avoiding the specified abnormal portion on the pad. Operation method of polishing apparatus.   The method of operating a chemical mechanical polishing apparatus according to claim 1, wherein in the step of moving the relative position of the wafer with respect to the pad with respect to the radial direction of the pad, the head and the wafer held by the head are moved. A platen that holds and rotates the pad;
A head that holds and rotates the wafer so that the rotating wafer contacts the rotating pad and is polished;
A torque measuring device that measures physical quantities corresponding to the rotational torque of the head at a plurality of circumferential positions on the pad;
A chemical mechanical polishing apparatus comprising: a control device that identifies an abnormal location on the pad based on the measured physical quantity. further,
A moving mechanism for moving the relative position of the head with respect to the platen with respect to the radial direction of the pad;
5. The control device according to claim 4, wherein the control device moves the relative position of the head with respect to the platen so as to be a trajectory of the wafer avoiding an abnormal point on the identified pad. Chemical mechanical polishing equipment.

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