JP2007287787A - Method and equipment for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deterioration of the in-plane uniformity of a polished wafer caused by the abrasion of a retainer ring in a polishing device of a semiconductor wafer. <P>SOLUTION: The deterioration of the in-plane uniformity of a polished semiconductor wafer caused by a variation in the profile of the footprint of a retainer ring is compensated by measuring the amount of abrasion of the retainer ring at predetermined timing and changing the height or polishing conditions of the retainer ring more than reduction in the thickness of the retainer ring. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for manufacturing a semiconductor device, and more particularly to improvement of a technique for polishing a semiconductor wafer using a polishing apparatus.

  In the manufacturing process of a semiconductor device, the level of flatness of the surface of the semiconductor device required when processing a pattern becomes strict as the semiconductor device becomes finer. Conventionally, the required flatness level has been dealt with by improving the buried film such as a coating film such as SOG (spin on glass) or reflow for annealing the BPSG film at a high temperature. Since the processing rules of semiconductor devices have become finer than 0.35 μm, a means for directly polishing semiconductor devices, called CMP (chemical mechanical polishing), has been generally used. Although this CMP is effective in eliminating the level difference on the surface of the semiconductor device, there is a problem that the in-plane uniformity of the polished film after polishing varies. Particularly in recent years, semiconductor devices have been processed on large-diameter wafers such as 300 mm wafers, and it has become important to improve the uniformity of the film to be polished. For this reason, it is difficult to ensure the required uniformity in the configuration of existing polishing apparatuses that are generally sold.

  As a general polishing operation in the prior art, after a retainer ring of a head holding a semiconductor wafer on a polishing pad is grounded at a predetermined pressure, pressure is applied to the semiconductor wafer via an air bag. At that time, the polishing pad is given a rotational motion, and the abrasive is supplied from the abrasive nozzle. The semiconductor wafer surface is polished by basic operations such as application of pressure, rotational movement, and supply of an abrasive. The periphery of the semiconductor wafer is in contact with the boundary where the action on the polishing pad extends. It is generally known that in the peripheral region of the semiconductor wafer within several mm from this boundary, the pressing force becomes non-uniform as a reaction of the downward deformation of the polishing pad. This non-uniform region can be shifted from the lower peripheral surface of the semiconductor wafer to the lower surface of the retainer ring by retainer ring. Further, by changing the pressure of the retainer ring, it is possible to change the profile of the polishing rate at the peripheral edge of the semiconductor wafer.

  The problem with polishing of semiconductor wafers is that when a large number of wafers are polished, the wear of retainer rings, which are generally made of resin, progresses, and the polishing rate profile at the periphery of the semiconductor wafer is the same. Even if the conditions are adopted, it is to change. Variations in polishing characteristics due to the wear of the retainer will be described with reference to the drawings.

  FIG. 5 shows a schematic diagram of a head portion of a general polishing apparatus. The head 1 of the CMP apparatus is a main part that brings a polishing action by pressing the semiconductor wafer 19 against the polishing pad 20. The retainer ring 10 may not be grounded depending on the polishing apparatus manufactured before the early 1990s and the type of the object to be polished. However, generally, a method in which the retainer ring 10 is actively grounded to the polishing pad 20 is the mainstream. The retainer ring 10 has a function of adjusting the uniformity in the vicinity of the periphery of the semiconductor wafer 19 as well as merely guiding the semiconductor wafer 19 that is not polished.

  As a general polishing operation, after the retainer ring 10 of the head 1 holding the semiconductor wafer 19 on the polishing pad 20 is grounded at a predetermined pressure, the air pressure is applied to the semiconductor wafer 19 through elastic membranes 18a to 18c. Apply pressure at. At that time, the polishing pad 20 is given a rotational motion, and the abrasive is supplied from the abrasive nozzle 21. The surface of the semiconductor wafer 19 is polished by basic operations such as pressure application, rotational movement, and supply of abrasive.

  FIG. 16 shows a schematic diagram in which the retainer ring 10 acts during the polishing operation. A certain pressure acts on the semiconductor wafer 19 through the membranes 18a to 18c. At this time, the peripheral edge of the semiconductor wafer 19 is in contact with a boundary portion that acts on the polishing pad 20. It is generally known that in the peripheral region of the semiconductor wafer within a few millimeters from this boundary portion, the pressing force becomes non-uniform as a reaction of the downward deformation of the polishing pad 20, as shown in FIG. . This non-uniform region can be shifted from the lower surface of the peripheral edge of the semiconductor wafer 19 to the lower surface of the retainer ring 10 by the retainer ring 10. Further, by changing the pressure of the retainer ring 10, it is possible to change the profile of the polishing rate at the peripheral portion of the semiconductor wafer 19.

  Variations in the polishing characteristics due to wear of the retainer ring 10 are described in several patent documents as follows. About this prior art, the outline | summary of the technique and the relationship of characteristic fluctuation | variation are demonstrated.

  Patent Document 1 describes a technique for easily and efficiently detecting the replacement timing because a desired polishing characteristic cannot be obtained when the retainer ring is worn. However, the invention described in this publication does not have an object or configuration for controlling the polishing characteristics.

  Patent Document 2 describes that there is a mechanism for adjusting the height of the retainer ring. However, this publication does not clearly describe how to adjust the height of the retainer ring with what standard.

  Patent Document 3 describes a polishing apparatus having a means for measuring the height of the retainer ring, a means for correcting the height, and a means for correcting one-side scraping of the retainer ring. However, in the invention described in this publication, since the polishing for correcting the half-cut is added, the wear rate of the retainer ring is increased. However, the life of the retainer ring is not extended by the height adjustment.

JP 2001-25962 A JP 2003-25217 A Japanese Patent Laid-Open No. 2003-273047

  Hereinafter, problems caused by retainer ring wear will be described. FIG. 17 shows the main part of the head for holding the wafer 19 in the polishing apparatus. There are several types of head structures. Here, a structure having a support body (membrane support) 22 supporting the membrane 18 fixed to the head is shown as an example. When the retainer ring 10 is worn and the relative distance to the membrane support 22 changes, the periphery of the semiconductor wafer 19 is supported in the vicinity of the periphery, so the reaction force of the elastic body is supported. The closer the position is, the more the pressure changes, and the effective pressure applied to the wafer 19 tends to change. FIG. 18 shows the data actually obtained with respect to the relationship between the depth of the groove formed in the retainer ring and the uniformity within the wafer surface generated on the wafer after polishing, which shows the amount of wear of the retainer ring, as a solid line. The vertical axis indicates the variation in the height of the wafer surface. It can be seen that as the wear of the retainer ring 10 progresses, the in-plane uniformity of the polished film deteriorates in the polished semiconductor wafer.

  The retainer ring has a wear amount of about 0.1 mm to 0.5 mm after polishing 1000 wafers, depending on the material. Conventionally, it has been common to discard the retainer ring when the retainer ring shows a wear amount of about 0.5 to 1.5 mm. In this case, there is a trade-off relationship that if the suppression of the change in the polishing characteristics is important, the replacement must be performed at a high frequency, and if the reduction in the replacement frequency is important, the change in the polishing characteristics must be allowed.

  Based on the above phenomenon, an experiment was performed to correct polishing conditions such as changing the height of the retainer ring based on the amount of wear of the retainer. However, although this correction works in the direction of suppressing the change in uniformity, as shown by the dotted line in FIG. 18, the in-plane uniformity cannot be returned to the initial state. When the cause of this difference was analyzed, it was found that the shape change of the retainer ring had an effect. In the retainer ring, as the polishing progresses, the amount of wear increases and the shape of the bottom surface of the ring is curved, and the effective pressure on the wafer near the retainer ring is caused by the increased amount of wear and the shape change. Changes. The two factors of increased wear and change in shape act in the same direction and work synergistically with respect to the effective pressure on the wafer. That is, as the polishing progresses, even under the same polishing conditions, the pressure on the wafer peripheral portion changes in a direction in which it effectively acts strongly due to these two factors. For this reason, when the polishing conditions are optimized when the retainer ring is new, the in-plane uniformity of the semiconductor wafer gradually deteriorates as the polishing time elapses.

  In view of the above, the present invention suppresses fluctuations in polishing characteristics caused by the amount of wear of the retainer ring and the shape change of the bottom surface. Another object of the present invention is to provide a semiconductor device manufacturing method and apparatus capable of extending the life of the retainer ring.

In order to achieve the above object, a manufacturing method of a semiconductor device according to a first aspect of the present invention includes a retainer ring that guides the periphery of a semiconductor wafer to be polished in a wafer in-plane direction, and a back surface of the semiconductor wafer in a thickness direction. In a method for manufacturing a semiconductor device, a semiconductor wafer is polished using a polishing apparatus having a wafer pressing portion that presses the wafer and a polishing pad that polishes the surface of the semiconductor wafer.
Obtaining the wear amount of the retainer ring at a predetermined timing;
Calculating a polishing condition correction amount based on the acquired wear amount;
And polishing the semiconductor wafer using a polishing condition obtained by adding the calculated polishing condition correction amount to the polishing condition employed before the wear amount acquisition step.

In addition, the semiconductor device manufacturing method according to the second aspect of the present invention includes a retainer ring that guides the periphery of a semiconductor wafer to be polished in the wafer surface direction, and a wafer pressing portion that presses the back surface of the semiconductor wafer in the thickness direction. And polishing the semiconductor wafer using a polishing apparatus having a polishing pad for polishing the surface of the semiconductor wafer,
Obtaining the wear amount of the retainer ring at a predetermined timing;
Calculating a retainer ring height correction value equal to or greater than a change in the thickness of the retainer ring corresponding to the acquired wear amount;
And polishing the semiconductor wafer by using the height of the retainer ring obtained by adding the calculated height correction value to the height of the retainer ring adopted before the wear amount acquisition step. .

Furthermore, the semiconductor device manufacturing apparatus according to the third aspect of the present invention includes a retainer ring that guides the periphery of a semiconductor wafer to be polished in the wafer surface direction, and a wafer pressing portion that presses the back surface of the semiconductor wafer in the thickness direction. And a semiconductor device manufacturing apparatus comprising a polishing apparatus having a polishing pad for polishing the surface of a semiconductor wafer,
Wear amount acquisition means for acquiring the wear amount of the retainer ring at a predetermined timing;
A calculating means for calculating a polishing condition correction amount based on the acquired wear amount;
Polishing condition setting means for setting a polishing condition obtained by adding the polishing condition correction amount calculated by the calculation means to the polishing condition adopted before the wear amount acquisition means acquires the wear amount;
The semiconductor wafer is polished using the set polishing conditions.

Further, the semiconductor device manufacturing apparatus according to the fourth aspect of the present invention includes a retainer ring that guides the periphery of the semiconductor wafer to be polished in the wafer surface direction, and a wafer pressing portion that presses the back surface of the semiconductor wafer in the thickness direction. And a semiconductor device manufacturing apparatus comprising a polishing apparatus having a polishing pad for polishing the surface of a semiconductor wafer,
Wear amount acquisition means for acquiring the wear amount of the retainer ring at a predetermined timing;
Calculating means for calculating a height correction value of the retainer ring equal to or greater than a change in the thickness of the retainer ring corresponding to the acquired wear amount;
The semiconductor wafer is polished by using the height of the retainer ring obtained by adding the calculated height correction value to the height of the retainer ring adopted before the wear amount acquisition step.

  In the semiconductor device manufacturing method according to the first aspect of the present invention and the semiconductor device manufacturing apparatus according to the third aspect, the polishing condition correction amount is calculated based on the wear amount of the retainer ring, and the calculated correction amount is calculated. Polishing conditions are set in addition to the previous polishing conditions, and polishing is performed using these polishing conditions. Further, in the semiconductor device manufacturing method according to the second aspect of the present invention and the semiconductor device manufacturing apparatus according to the fourth aspect of the present invention, the height correction value of the retainer ring equal to or greater than the change in thickness corresponding to the wear amount of the retainer ring. Use to adjust the height of the retainer ring. With these configurations, unlike conventional manufacturing methods and apparatuses that simply perform height correction of the retainer ring based on a change in thickness corresponding to the amount of wear of the retainer ring, polishing with high in-plane uniformity is performed for semiconductor wafer polishing. In addition, the life of the retainer ring can be extended. For this reason, at the time of polishing the semiconductor wafer, it is possible to both reduce the operating cost of the manufacturing apparatus and improve the quality of the product.

  In the method for manufacturing a semiconductor device according to the first aspect of the present invention, the calculated polishing condition correction amount includes a polishing condition correction amount corresponding to the acquired wear amount and a polishing corresponding to the shape change of the retainer ring. It is preferable to include a condition correction amount. By correcting the polishing condition by adding the polishing condition correction amount corresponding to the change in the shape of the retainer ring to the polishing condition correction amount corresponding to the wear amount, the in-plane uniformity of the wafer after polishing is improved. Instead of this, the calculation step further calculates a height correction value of the retainer ring based on the acquired wear amount, and the polishing step is further adopted before the wear amount acquisition step. The object of the present invention can also be achieved by using the height of the retainer ring obtained by adding the calculated height correction value to the height of the retainer ring. In this case, it is preferable that the height correction value of the retainer ring is equal to the change in the thickness of the retainer ring corresponding to the acquired amount of wear, and calculation for calculation is facilitated.

  In the semiconductor device manufacturing method according to the first and second aspects of the present invention, it is preferable that the calculation step calculates the polishing condition correction amount using a predetermined approximate expression. Calculation is simplified and real-time control of the polishing apparatus is facilitated.

  In the wear amount acquisition step, the thickness of the retainer ring may be actually measured. In this case, it is preferable to measure the depth of the groove formed on the surface of the retainer ring that contacts the polishing pad. Further, instead of actually measuring, the wear amount of the retainer ring may be estimated based on the accumulated time of polishing the semiconductor wafer and the polishing conditions employed in the polishing. In this case, the wear amount can be easily obtained.

  In the semiconductor device manufacturing apparatus according to the third aspect of the present invention, the calculating means further calculates a height correction value of the retainer ring based on the acquired wear amount, and the wear amount acquiring means is the wear amount. It is also a preferred aspect to polish the semiconductor wafer by adding the retainer ring height correction value calculated by the calculating means to the height of the retainer ring adopted before acquiring the above.

  Next, a semiconductor device manufacturing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a top view showing a main part of a semiconductor wafer polishing apparatus. The polishing apparatus includes a head 1 that holds and pressurizes a semiconductor wafer, a cloth 2 that imparts a turning motion to the head 1, a platen 3 that has a polishing pad and that provides a rotational motion for polishing, and a dresser 8 that adjusts the surface state of the polishing pad. And a general mechanism such as a load / unload unit 4 for attaching / detaching a semiconductor wafer to / from the head 1, a robot 5 constituting a transfer mechanism for transferring the semiconductor wafer into or out of the apparatus, and a cleaning mechanism 6. . In addition to these general mechanisms, based on the present invention, a measuring mechanism for measuring a groove step formed on the lower surface of the retainer ring on a trajectory 1a through which the head 1 pivots and passes, for example, a laser displacement meter And a sensor 7. The sensor 7 is installed between the platens 3 when a plurality of platens 3 are provided. Alternatively, it may be in the load / unload unit 4 for removing and attaching the wafer. Note that a mechanism for protecting the displacement gauge and sensor 7 from slurry or pure water may be provided on the laser displacement gauge and sensor 7 as necessary. Further, instead of the laser displacement meter and the sensor 7, a measuring device that directly measures the thickness or height of the retainer ring 10 may be disposed in the polishing device.

  FIG. 2 is a side view showing the main part of the measurement mechanism in the semiconductor device manufacturing apparatus of the embodiment. A laser displacement meter and sensor 7 are provided on the lower surface of the retainer ring 10 for guiding the wafer, and the laser displacement meter and sensor 7 can measure the depth of the retainer ring groove 11. As a means for grasping the amount of wear of the retainer ring 10, instead of these, a CCD camera may be installed on the side of the head in the apparatus, and a change in thickness or height may be measured by image recognition. The polishing apparatus further calculates the amount of change in the retainer ring 10 thickness from the measured value of the retainer ring 10 with the operation control unit 12 that controls the head operation when measuring the retainer ring as shown in FIG. A calculation unit 13 that calculates an optimum polishing condition by a preset approximate expression, a storage unit 14 that holds the calculation value, and a pressure control unit 15 that reflects the calculation value in the pressure condition of the polishing apparatus and switches the pressure to the optimum condition. And an instruction unit 17 that controls these and gives instructions to the polishing mechanism 16. Note that the approximate expression applied by the calculation unit 13 is obtained by obtaining in advance a polishing condition that is optimal for each amount of wear during retainer ring wear.

  As described above, the polishing apparatus of the above embodiment includes a mechanism 7a that detects a change in the thickness of the retainer ring, a mechanism 13 that calculates optimum polishing conditions based on the thickness, and the calculated value of the polishing apparatus. And a mechanism 12 that performs the capture and execution as a condition. Therefore, the influence of the wear condition of the retainer ring is removed, and a polishing apparatus having stable polishing characteristics can be obtained.

  Next, with reference to FIGS. 1-5, the manufacturing method of the semiconductor device implemented with the grinding | polishing apparatus which concerns on the said embodiment is demonstrated. FIG. 4 shows a flowchart showing processing in this polishing apparatus. When instructed to start the polishing process, the polishing apparatus first checks a flag indicating whether or not the head or the retainer ring is immediately after replacement (step S1). If it is just after replacement | exchange, the wear amount of a retainer ring will be measured by measuring the height or groove | channel level | step difference of a retainer ring (step S3). If it is not immediately after replacement, it is checked whether or not the number of processed sheets exceeds a certain number (step S2), and the process proceeds to step S3. The measured value obtained in step S3 is transferred (step S4), and calculation processing is performed using an approximate expression for obtaining an optimum condition based on the retaining ring height or the groove step (step S5). The optimum condition obtained by the calculation is input, set in the storage unit as the optimum condition (step S6), and polishing is performed (step S7). Thereafter, it is determined whether or not the polishing is completed (step S8), and if not completed, the process returns to step S2, and the optimum number obtained by the calculation unit and stored in the storage unit is obtained up to the preset number (N). The conditions are read (step S9), and polishing is performed using them as the optimum conditions (steps S6 to S8).

  When the number of polishing processes reaches a predetermined number or more and is determined to be a lot end (step S2), the measuring mechanism 7 again measures the amount of wear of the retainer ring (step S3), and an optimum condition calculation unit 13 (step S4). The optimum condition is calculated by the optimum condition calculation unit 13 (step S8), and the calculated condition is input to the polishing condition. For example, the retainer ring pressure is changed from 10 PSI to 9.8 PSI (step S6). Thereafter, from the next lot, polishing is performed under new polishing conditions in which the conventional conditions are corrected by a correction amount calculated corresponding to the amount of retainer ring wear. When the processing is finished in a state where the number of processed sheets is less than a predetermined value and polishing is performed again, after the start, a flag check (step S1) of the retainer ring is performed and the process is performed in the same flow as described above. .

  Hereinafter, details of the operations of the polishing and the retainer ring wear amount measurement in the method of manufacturing a semiconductor device according to the embodiment will be described. The top view which shows the principal part of the grinding | polishing apparatus of FIG. 1 is referred. The semiconductor wafer is transferred by the robot 5 from the interface 9 and is sucked and held by the head 1 by the load / unload unit 4. After that, it moves onto the platen 3 and is brought into contact with the polishing pad on the platen 3 to which the abrasive is supplied and given the rotational movement. Here, reference is made to a side view showing a main part of the general polishing apparatus of FIG. A predetermined pressure is applied to the retainer ring 10, and the wafer 19 is pressurized through the inner membranes 18 a to 18 c. At this time, the membranes 18a to 18c are divided into a plurality of regions, and the pressures at the respective portions 18a to 18c can be controlled by respective set values.

  In general, the polishing surface is treated to adjust the surface state by a dresser 8 that adjusts the surface state of the polishing pad 20 simultaneously with polishing. When the polishing is completed, the polishing pad 20, the head 1, and the wafer 19 are rinsed with pure water. Thereafter, the wafer 19 is peeled off from the surface of the polishing pad 20, moved to the load / unload section, moved by the robot, cleaned by the cleaning mechanism, and stored in the FOUP or the like of the apparatus interface section. The above is a general flow. In this embodiment, after the semiconductor wafer 19 is collected, a process of measuring the wear amount of the retainer ring is included. Prior to measurement, the head 1 in an idle state is rotated at a high speed to temporarily remove water adhering to the retainer ring 10. Furthermore, you may attach the unit which performs an air blow.

  As shown in FIG. 2, the retainer ring 10 moves so as to be positioned above the sensor 7, and the height of the retainer ring 10 from the reference position is measured by the sensor 7 of the laser displacement meter. When the retainer ring 10 has a groove, the groove depth is measured while rotating the head at a low speed. In addition, the thickness of the retainer ring 10 and the depth of the groove are manufactured with a predetermined processing accuracy, and individual differences are suppressed within a predetermined range. Further, the change of the polishing condition from the wear amount of the retainer ring 10 is not limited to only one condition.

  The pressure of the retainer ring 10 as shown in FIG. 5 and the pressure in the vicinity of the edge of the semiconductor wafer 19 such as the membrane 18a can be variously changed and combined. As described above, the data of the actual retainer ring pressure dependency at the time of retainer ring wear and the pressure dependency in the vicinity of the wafer edge are acquired in advance by a plurality of wear amounts, and an approximate expression of the optimum condition is prepared. The pressure is changed by this approximate expression.

  As described above, in the semiconductor device manufacturing apparatus and the semiconductor device manufacturing method according to the above embodiments, the amount of wear of the retainer ring is detected, and the characteristic change in the wear process caused by the wear of the retainer ring is predicted. By having the means and means for compensating for the characteristic change based on this prediction, here, the means for changing the polishing conditions, it is possible to suppress the change in the polishing characteristics caused by the wear of the retainer ring.

  In the above-described embodiment, it is possible to suppress the fluctuation of the polishing characteristics accompanying the wear of the retainer ring, which is a problem in the polishing apparatus, and to suppress the yield reduction of the semiconductor device product. At the same time, it is possible to improve production efficiency and reduce costs as compared with the prior art. FIG. 6 shows a state of improvement obtained by the semiconductor device manufacturing apparatus according to the above-described embodiment in comparison with a case where correction based on the wear amount is not performed. The horizontal axis indicates the amount of wear of the retainer ring, and the vertical axis indicates the difference in the in-plane height of the semiconductor wafer after polishing. In the above embodiment, it is shown that a uniform height is obtained in the wafer surface and the in-plane uniformity is improved almost without depending on the thickness of the retainer ring.

  A second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram illustrating a configuration of a semiconductor manufacturing apparatus according to the second embodiment. In this embodiment, as a general mechanism, a retainer ring measurement mechanism 7a that measures the amount of wear of the retainer ring, a calculation unit 13 that performs calculation of optimization of the retainer ring height, a storage unit 14 that stores the calculation, and a polishing mechanism 16 The apparatus operation control unit 12, the pressure control unit 15, and the instruction unit 17 that controls the whole are provided. In this embodiment, in addition to these general mechanisms, a retainer height control unit 25 that controls the retainer height to an optimum value and a change mechanism 24 that changes the height of the retainer ring are provided.

  In the retainer height control unit 25, the correlation data between the retainer ring wear amount and the correction value is actually acquired, and the optimum correction amount is calculated by an approximate expression to control the polishing conditions. For example, when investigating the optimum height correction value, if the retainer ring is worn by 0.5 mm, the correction of 0.6 mm is performed, if the wear of 1.0 mm is worn, the correction of 1.3 mm is corrected, and if the wear of 1.5 mm is worn, the correction is 2.0. The polishing characteristic can be approximated to the initial state of the retainer ring by adding a correction equal to or greater than the correction amount corresponding to the wear amount so that the mm correction is necessary. A value calculated by this approximate expression is input to the control unit 12.

  FIG. 8 shows an example of a mechanism for changing the height of the retainer ring, and is a schematic diagram of a main part when the head is viewed from the side. Between the retainer ring 10 and the carrier 29 that connects it, there is a pulse motor 26 that drives a precision ball screw at the slide part 28 and the center of the slide part. The rotation of the pulse motor 26 drives the retainer ring 10 up and down. It is a mechanism to do. A retainer fixing membrane 27 is provided between the carrier 29 and the retainer ring 10 to fix the position of the retainer ring 10 during polishing.

  FIG. 9 is a flowchart showing processing in the semiconductor device manufacturing apparatus of the present embodiment. When the instructing unit instructs to start the polishing process, first, a flag is checked as to whether or not the head or the retainer ring is immediately after replacement (step S11). If it is immediately after the replacement, it is confirmed that the number of polishing treatments is N or less (step S12), and the height of the retainer ring or the groove step is measured (step S13). The measured value is transferred from the sensor (step S14), and the optimum value for the retainer ring height correction is calculated by an approximate expression based on the retainer ring height or the groove step and stored (step S15). Subsequently, the height of the retainer ring 10 is controlled so as to be the optimum height correction value (step S16). In general, in a retainer ring that is unused and manufactured with a predetermined accuracy, there is almost no correction and the performance condition is used.

  Thereafter, up to the set number of sheets, the polishing is repeatedly performed based on the previously stored optimum height correction value (step S17). It is confirmed that the polishing is not finished (step S18), and the process returns to step S12. If the number of processed sheets is N or less in step S12, the previously stored correction value is input, polishing is performed based on the correction value (steps S19, S16 to S18), and the process returns to step S12. In step S12, when the number of polishing processes reaches a certain number or more and it is determined that the lot is at the end, the correction from the next lot is performed with a correction amount equal to or greater than the correction amount corresponding to the wear amount of the retainer ring 10. Polish. That is, the wear amount of the retainer ring is measured (step S13) and transferred to the optimum height correction calculation unit (step S14). Thereafter, the height of the retainer ring 10 is adjusted so as to be the optimum height (step S16). When the processing is finished in a state where the number of processed sheets is less than a certain value and polishing is performed again, after the start, the flag of the retainer ring 10 is checked and the processing is performed in the same flow as described above.

  FIG. 10 plots the in-plane uniformity obtained in the second embodiment by the thickness of the retainer ring during polishing. For comparison, a case where correction is not performed using the wear amount, a case where correction is performed using a correction amount corresponding to the wear amount, and a case where correction is performed according to the present embodiment are shown. As can be understood from the figure, in the present embodiment, characteristic compensation that cannot be compensated by the correction amount corresponding to the wear amount of the retainer ring was obtained.

  A third embodiment of the present invention will be described. In this embodiment, instead of directly monitoring the wear amount of the retainer ring, the wear amount is calculated and estimated from the polishing condition and the accumulated value of the polishing time. In this case, correlation data between the accumulated value of the polishing time and the amount of wear under specific polishing conditions is acquired in advance, and the calculation is performed based on the approximate expression, and the polishing conditions are changed as in the first embodiment. In addition, when there are a plurality of conditions with different polishing conditions such as polishing pressure and platen rotation speed, a coefficient under each condition is obtained, and aX + bY + cZ (x, y, z: time, a, The amount of wear is estimated by adding (b, c: wear coefficient).

  FIG. 11 shows a configuration of a polishing apparatus in a semiconductor device manufacturing apparatus according to the third embodiment of the present invention, and FIG. 12 shows a processing state in the polishing apparatus in a flowchart. When the instructing unit 17 instructs the start of the polishing process, first, a flag is checked as to whether the head or the retainer ring 10 has just been replaced (step S21). If it is just after replacement | exchange, grinding | polishing will be performed according to the basic conditions set initially (steps S29 and S27). Thereafter, until the set estimated wear amount value is reached (step S22), the basic condition set from the storage unit is input (step S30), and the polishing is repeatedly performed using it as the optimum condition (steps S26 to S27). . In step S22, when the wear amount cumulative value reaches a predetermined value or more and it is determined that the lot end is reached, the estimated value of the retaining ring wear amount is transferred to the optimum condition calculation unit 13. The optimum condition calculation unit 13 calculates the optimum condition based on the estimated wear amount (step S25), and the calculated condition is set as the optimum polishing condition (step S26). From the next lot, polishing is performed under new conditions corresponding to the wear amount of the retainer ring 11 (step S27). In the case where the processing is finished in a state where the number of processed sheets is less than a predetermined value and polishing is performed again, after the start, the flag is checked for the retainer ring, and processing is performed in the same flow as described above.

  In the present embodiment, no special hardware such as a sensor or a mechanism for adjusting the retainer ring height is required, and the effect of the present invention can be obtained by changing only the software, thereby improving the cost efficiency.

  The semiconductor device manufacturing apparatus according to the fourth embodiment of the present invention approximates the wear amount of the retainer ring as in the third embodiment. However, unlike the third embodiment, the height of the retainer ring 10 is changed as in the second embodiment. FIG. 13 is a block diagram showing the configuration of the polishing apparatus in the semiconductor device manufacturing apparatus according to this embodiment. FIG. 14 is a flowchart showing the state of processing in the polishing apparatus. In FIG. 14, the height correction of the retainer ring 10 is employed instead of the polishing conditions in step S29 and step S26 of FIG. Otherwise, FIG. 14 has the same steps as FIG. In the present embodiment, the effects of the present invention can be obtained while adopting a simpler configuration than in the second embodiment.

  FIG. 15 is a flowchart showing the processing of the polishing apparatus in the semiconductor device manufacturing apparatus according to the fifth embodiment of the present invention. This embodiment employs a configuration in which the first embodiment and the second embodiment are combined. In the present embodiment, the wear amount of the retainer ring is measured at a predetermined timing (step S43), the height of the retainer ring is corrected, and the polishing condition is further corrected (step S46). When correcting the retainer ring, for example, when correcting to match the initial thickness, correction of polishing conditions such as polishing pressure is applied to the shape change of the retainer ring.

  A sixth embodiment of the present invention will be described. The polishing apparatus in the semiconductor device manufacturing apparatus according to the present embodiment has the same configuration as the conventional polishing apparatus, and the thickness of the retainer ring 10 is measured by periodically removing the head from the polishing apparatus. Measure the amount of wear. Prepare shims of different thicknesses, insert shims with different thicknesses according to the amount of wear, give a correction greater than the correction amount corresponding to the decrease in the height of the retainer ring 10, and retainer ring Compensates for wear and shape changes. That is, a shim thicker than the wear amount is inserted. For example, a 0.6 mm thick shim is inserted when the retainer ring is worn by 0.5 mm, a 1.3 mm thick shim is inserted when the retainer ring is worn by 1.0 mm, and a 2.0 mm thick shim is inserted when the retainer ring is worn by 1.5 mm. . In this embodiment, the polishing apparatus itself is the same as the conventional polishing apparatus, but the polishing characteristics are stabilized by changing only the polishing method.

  Although the present invention has been described based on the preferred embodiments, the method and apparatus for providing a semiconductor device according to the present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made from the configuration of the above-described embodiment. Those modified and changed as described above are also included in the scope of the present invention.

The top view which shows the grinding | polishing apparatus in the manufacturing apparatus of the semiconductor device which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the thickness measurement part of the retainer ring in the grinding | polishing apparatus of FIG. The block diagram of the polisher of FIG. The flowchart which shows the process of the grinding | polishing apparatus of FIG. A general sectional view of a polisher. The graph which shows the relationship between the thickness of a retainer ring and the in-plane uniformity in the wafer after grinding | polishing obtained by 1st Embodiment. The block diagram of the grinding | polishing apparatus in the manufacturing apparatus of the semiconductor device which concerns on the 2nd Embodiment of this invention. Sectional drawing of the principal part of the grinding | polishing apparatus of FIG. The flowchart which shows the process of the grinding | polishing apparatus of FIG. The graph which shows the thickness of the retainer ring obtained in 2nd Embodiment, and the in-plane uniformity in the wafer after grinding | polishing. The block diagram of the polisher in the manufacturing apparatus of the semiconductor device which concerns on the 3rd Embodiment of this invention. The flowchart which shows the process in the grinding | polishing apparatus of FIG. The block diagram of the polisher in the manufacturing apparatus of the semiconductor device which concerns on the 3rd Embodiment of this invention. 14 is a flowchart showing processing of the polishing apparatus of FIG. 9 is a flowchart showing processing of a polishing apparatus in a semiconductor device manufacturing apparatus according to a fifth embodiment of the present invention. Sectional drawing of the principal part of the conventional grinding | polishing apparatus, and the graph which shows the pressure distribution in a grinding | polishing apparatus. The principal part sectional drawing of the polish device which shows the problem in the conventional polish device. The graph which shows the relationship between the abrasion amount of the retainer ring in the conventional grinding | polishing apparatus, and the in-plane uniformity in the wafer after grinding | polishing.

Explanation of symbols

1: Head 1a: Head rotation locus 2: Cross 3: Platen 4: Load / unload unit 5: Robot 6: Cleaning mechanism 7: Sensor 8: Dresser 7a: Retainer ring measuring mechanism 9: Interface 10: Retainer ring 11: Retainer Ring groove 12: device operation control unit 13: calculation unit 14: storage unit 15: pressure control unit 16: polishing mechanism 17: instruction units 18a, 18b, 18c: membrane 19: semiconductor wafer 20: polishing pad 22: membrane support 23: Spindle 24: Retainer ring height changing mechanism 25: Retainer ring height control section 26: Pulse motor 27: Retainer fixing membrane 28: Slide section

Claims (11)

A polishing apparatus having a retainer ring that guides the periphery of a semiconductor wafer to be polished in a wafer in-plane direction, a wafer pressing portion that presses the back surface of the semiconductor wafer in a thickness direction, and a polishing pad that polishes the surface of the semiconductor wafer is used. In a manufacturing method of a semiconductor device for polishing a semiconductor wafer,
Obtaining the wear amount of the retainer ring at a predetermined timing;
Calculating a polishing condition correction amount based on the acquired wear amount;
And a step of polishing the semiconductor wafer using a polishing condition obtained by adding the calculated polishing condition correction amount to the polishing condition employed before the wear amount acquisition step.   2. The semiconductor device according to claim 1, wherein the calculated polishing condition correction amount includes a polishing condition correction amount corresponding to the acquired wear amount and a polishing condition correction amount corresponding to a shape change of the retainer ring. Production method. The calculating step further calculates a height correction value of the retainer ring based on the acquired wear amount,
The semiconductor device according to claim 1, wherein the polishing step further uses a height of the retainer ring obtained by adding the calculated height correction value to a height of the retainer ring adopted before the wear amount acquisition step. Manufacturing method.   The method of manufacturing a semiconductor device according to claim 3, wherein the height correction value of the retainer ring is equal to a change in thickness of the retainer ring corresponding to the acquired amount of wear. A polishing apparatus having a retainer ring that guides the periphery of a semiconductor wafer to be polished in a wafer in-plane direction, a wafer pressing portion that presses the back surface of the semiconductor wafer in a thickness direction, and a polishing pad that polishes the surface of the semiconductor wafer is used. In a manufacturing method of a semiconductor device for polishing a semiconductor wafer,
Obtaining the wear amount of the retainer ring at a predetermined timing;
Calculating a retainer ring height correction value equal to or greater than a change in the thickness of the retainer ring corresponding to the acquired wear amount;
And polishing the semiconductor wafer by using the height of the retainer ring obtained by adding the calculated height correction value to the height of the retainer ring adopted before the wear amount acquisition step. A method for manufacturing a semiconductor device.   The method of manufacturing a semiconductor device according to claim 1, wherein the calculating step calculates the polishing condition correction amount using a predetermined approximate expression.   The method of manufacturing a semiconductor device according to claim 1, wherein the wear amount acquisition step includes a step of measuring a depth of a groove formed on a surface of the retainer ring that contacts the polishing pad.   The wear amount acquisition step includes a step of estimating the wear amount of the retainer ring based on an accumulated time of polishing the semiconductor wafer and a polishing condition employed in the polishing. The manufacturing method of the semiconductor device as described in any one of Claims 1-3. A polishing apparatus having a retainer ring that guides the periphery of a semiconductor wafer to be polished in a wafer in-plane direction, a wafer pressing portion that presses the back surface of the semiconductor wafer in a thickness direction, and a polishing pad that polishes the surface of the semiconductor wafer. In semiconductor device manufacturing equipment,
Wear amount acquisition means for acquiring the wear amount of the retainer ring at a predetermined timing;
A calculating means for calculating a polishing condition correction amount based on the acquired wear amount;
Polishing condition setting means for setting a polishing condition obtained by adding the polishing condition correction amount calculated by the calculation means to the polishing condition adopted before the wear amount acquisition means acquires the wear amount;
A semiconductor device manufacturing apparatus, wherein a semiconductor wafer is polished using the set polishing conditions. The calculation means further calculates a height correction value of the retainer ring based on the acquired wear amount,
The semiconductor wafer is polished by adding a retainer ring height correction value calculated by the calculation means to a retainer ring height adopted before the wear amount acquisition means acquires the wear amount. Semiconductor device manufacturing equipment. A polishing apparatus having a retainer ring that guides the periphery of a semiconductor wafer to be polished in a wafer in-plane direction, a wafer pressing portion that presses the back surface of the semiconductor wafer in a thickness direction, and a polishing pad that polishes the surface of the semiconductor wafer. In semiconductor device manufacturing equipment,
Wear amount acquisition means for acquiring the wear amount of the retainer ring at a predetermined timing;
A calculating means for calculating a height correction value of the retainer ring equal to or more than a change in the thickness of the retainer ring corresponding to the acquired amount of wear;
A semiconductor device is manufactured by polishing a semiconductor wafer by using the height of the retainer ring obtained by adding the calculated height correction value to the height of the retainer ring adopted before the wear amount acquisition step. apparatus.

Images